Part 5C: Specific Vessel Types (Chapters 1-6)

RULES FOR BUILDING AND CLASSING

STEEL VESSELS
2012

PART 5C
SPECIFIC VESSEL TYPES (CHAPTERS 1-6)

American Bureau of Shipping

Incorporated by Act of Legislature of
the State of New York 1862

Copyright © 2011
American Bureau of Shipping
ABS Plaza
16855 Northchase Drive
Houston, TX 77060 USA
F o r e w o r d

Foreword
In association with the introduction of the Common Structural Rules for Double Hull Oil Tankers and Bulk
Carriers, respectively, on 1 April 2006, Part 5 of the Rules for Building and Classing Steel Vessels, 2007 was
divided into three Sub-parts, 5A, 5B and 5C. The contents and application of each Part are as follows:

Contents
Part 5A: Common Structural Rules for Double Hull Oil Tankers
Part 5B: Common Structural Rules for Bulk Carriers
Part 5C: This Part is divided into two separate booklets as follows:
Chapters 1 to 6: Tankers not covered by Part 5A, Bulk Carriers not covered by
Part 5B and Container Carriers
Chapters 7 to 10: Passenger Vessels, Liquefied Gas Carriers, Chemical Carriers
and Vessels Intended to Carry Vehicles.

Application – Oil Tankers

The structural requirements in Part 5A of the Rules are applicable for double hull oil tankers of 150 m in
length and upward, with structural arrangements as specified in Part 5A, Section 2.
For oil tankers with structural arrangements not covered by Part 5A, the requirements in Part 5C, Chapters
1 or 2, are to be complied with.

Application – Bulk Carriers

The structural requirements in Part 5B of the Rules are applicable for single side skin and double side skin
bulk carriers of 90m in length and upward, with structural arrangements as specified in Part 5B, Chapter 1,
Section 1.
For vessels intended to carry ore or bulk cargoes, other than the single side skin or double side skin bulk
carriers of 90 m in length and upward with structural arrangements as specified in Part 5B, Chapter 1,
Section 1, the requirements in Part 5C, Chapters 3 or 4 are to be complied with.

Application – ABS Construction Monitoring Program

These compulsory requirements for CSR notation are specified in Part 5C, Appendix 2.

Application – Onboard Systems for Oil Tankers and Bulk Carriers

The onboard systems for all tankers are to comply with the requirements of Part 5C, Chapter 1, Section 7,
and for all bulk carriers are to comply with the requirements of Part 5C, Chapter 3, Section 7 of the Rules.

The following flow chart indicates the application of the Rules and typical Class Notations for tanker and bulk
carrier vessels, of which arrangements and scantlings are in full compliance with the Rules:

ii ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

 Vessels Intended to Carry Oil in Bulk Vessels Intended to Carry Ore or Bulk Cargoes

L ≥ 150 m? L ≥ 90 m?

Yes Yes

No Arrangement and No
Arrangement and
layout comply with
layout comply with
5A-1-2/3.1.2 and
5B-1-1/1.1.2?
5A-1-2/Fig 2.3.1?

Yes Yes

Part 5A, Chapter 1: Part 5B, Chapters 1 through 13:

Common Structural Rules for Common Structural Rules for
Double Hull Oil Tankers, Bulk Carriers,
and and
Part 5C, Appendix 2 Part 5C, Appendix 2
Part 5C, Chapter 1, Section 7 Part 5C, Chapter 3, Section 7

À A1 Oil Carrier, CSR, AB-CM À A1 Bulk Carrier, CSR, AB-CM

plus plus
appropriate notations for oil carriers appropriate notations for bulk carriers

Part 5C, Chapter 1, Part 5C, Chapter 3,

Appendix 1 to Part 5C Appendix 1 to Part 5C
(L ≥ 150 m) (L ≥ 150 m)
Or

À A1 Oil Carrier, SH, SHCM À A1 Bulk Carrier, SH, SHCM

plus plus
appropriate notations for oil carriers appropriate notations for bulk carriers

Part 5C, Chapter 2 Part 5C, Chapter 4

(L < 150 m) (L < 150 m)

À A1 Oil Carrier À A1 Bulk Carrier

plus plus
appropriate notations for oil carriers appropriate notations for bulk carriers

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 iii
R u l e C h a n g e N o t i c e ( 2 0 1 2 )

Rule Change Notice (2012)

The effective date of each technical change since 1993 is shown in parenthesis at the end of the
subsection/paragraph titles within the text of each Part. Unless a particular date and month are shown, the
years in parentheses refer to the following effective dates:
(2000) and after 1 January 2000 (and subsequent years) (1996) 9 May 1996
(1999) 12 May 1999 (1995) 15 May 1995
(1998) 13 May 1998 (1994) 9 May 1994
(1997) 19 May 1997 (1993) 11 May 1993

Listing by Effective Dates of Changes from the 2011 Rules

EFFECTIVE DATE 1 January 2012 – shown as (2012)

(based on the contract date for new construction between builder and Owner)
Part/Para. No. Title/Subject Status/Remarks
5C-1-7/1.7.2 Spaces Adjacent to Cargo Tanks To provide for special consideration of cases where short lengths of
piping serving the segregated ballast tanks pass through the bow
thruster room.
5C-1-7/5.3.2(b) Hazards To provide for special consideration of cases where short lengths of
piping serving the segregated ballast tanks pass through the bow
thruster room.
5C-1-7/7.7iv) <No Title> To provide for alternative arrangements of stop-check valves to
facilitate access by the crew t for closure as well as maintenance.
5C-1-7/17.1.4 Gas Detection System To align the Rules with the Fire Safety Systems Code (Introduction
of new Chapter 16 for FSS Code) per Resolution MSC.292(87)
adopted on 21 May 2010.
5C-1-7/19.5.5 Gas Sampling System for Oil Carriers To align the requirements with IMO Resolution MSC.291(87)
(New) 20,00 DWT and Above
5C-1-7/19.5.6 Oil Tankers Provided with Constantly To align the requirements with IMO Resolution MSC.291(87)
(New) Operating Inerting Systems
5C-1-7/19.5.7 Cargo Pump-rooms To align the requirements with IMO Resolution MSC.291(87)
(New)
5C-1-7/20 Gas Detection System To align the Rules with the Fire Safety Systems Code (Introduction
(New) of new Chapter 16 for FSS Code) per Resolution MSC.292(87)
adopted on 21 May 2010.
5C-3-73.3 Vessels Carrying Low Fire Risk To update the Rules in accordance with IMO MSC/Circ.1146.
Cargoes

iv ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

PART Table of Contents

5C
Specific Vessel Types

CONTENTS
CHAPTER 1 Vessels Intended to Carry Oil in Bulk (150 meters (492 feet)
or more in Length) ................................................................................. 1
Section 1 Introduction ..........................................................................13
Section 2 Design Considerations and General Requirements ............20
Section 3 Load Criteria ........................................................................24
Section 4 Initial Scantling Criteria ........................................................65
Section 5 Total Strength Assessment................................................120
Section 6 Hull Structure Beyond 0.4L Amidships ..............................134
Section 7 Cargo Oil and Associated Systems ...................................148

Appendix 1 Guide for Fatigue Strength Assessment of Tankers..........190

Appendix 2 Calculation of Critical Buckling Stresses ...........................219
Appendix 3 Application to Single Hull Tankers .....................................230
Appendix 4 Application to Mid-deck Tankers........................................241
Appendix 5 Guide for Hull Girder Ultimate Strength Assessment of
Oil Carriers.........................................................................245

CHAPTER 2 Vessels Intended to Carry Oil in Bulk (Under 150 meters

(492 feet) in Length) ........................................................................... 256
Section 1 Introduction ........................................................................259
Section 2 Hull Structure .....................................................................265
Section 3 Cargo Oil and Associated Systems ...................................281

Appendix 1 Guide for Hull Girder Shear Strength for Tankers .............282

CHAPTER 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 meters

(492 feet) or more in Length)............................................................. 286
Section 1 Introduction ........................................................................299
Section 2 Design Considerations and General Requirements ..........306
Section 3 Load Criteria ......................................................................310
Section 4 Initial Scantling Criteria ......................................................348
Section 5 Total Strength Assessment................................................430
Section 6 Hull Structure Beyond 0.4L Amidships ..............................444
Section 7 Cargo Safety and Vessel Systems ....................................467

Appendix 1 Guide for Fatigue Strength Assessment of Bulk Carriers......473

Appendix 2 Calculation of Critical Buckling Stresses ...........................510
Appendix 3 The Design and Evaluation of Ore and Ore/Oil Carriers .....521

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 v

 Appendix 4 Load Cases for Structural Analysis with Respect to
Slamming ...........................................................................526
Appendix 5a Longitudinal Strength of Bulk Carriers in Flooded
Conditions ..........................................................................529
Appendix 5b Bulk Carriers in Flooded Conditions – Corrugated
Transverse Watertight Bulkheads......................................531
Appendix 5c Bulk Carriers in Flooded Conditions – Permissible
Cargo Loads in Holds ........................................................543
Appendix 6 Harmonized System of Notations and Corresponding
Design Loading Conditions for Bulk Carriers.....................549
Appendix 7 Guide for Hull Girder Ultimate Strength Assessment of
Bulk Carriers ......................................................................558

CHAPTER 4 Vessels Intended to Carry Ore or Bulk Cargoes (Under

150 meters (492 feet) in Length)........................................................ 569
Section 1 Introduction ........................................................................571
Section 2 Hull Structure .....................................................................574
Section 3 Cargo Safety and Vessel Systems ....................................584

CHAPTER 5 Vessels Intended to Carry Containers (130 meters (427 feet)

to 450 meters (1476 feet) in Length) ................................................. 585
Section 1 Introduction ........................................................................594
Section 2 Design Considerations and General Requirements ..........597
Section 3 Load Criteria ......................................................................601
Section 4 Initial Scantling Criteria ......................................................644
Section 5 Total Strength Assessment................................................711
Section 6 Hull Structure Beyond 0.4L Amidships ..............................724
Section 7 Cargo Safety ......................................................................774

Appendix 1 Guide for Fatigue Strength Assessment of Container

Carriers ..............................................................................777
Appendix 2 Calculation of Critical Buckling Stresses ...........................826
Appendix 3 Definition of Hull Girder Torsional Properties ....................840
Appendix 4 Guide for Hull Girder Ultimate Strength Assessment of
Container Carriers..............................................................842

CHAPTER 6 Vessels Intended to Carry Containers (Under 130 meters

(427 feet) in Length) ........................................................................... 853
Section 1 Introduction ........................................................................854
Section 2 Hull Structure .....................................................................855
Section 3 Cargo Safety ......................................................................856

Appendix 1 Guide for Strength Assessment of Container Carriers –

Vessels Under 130 meters (427 feet) in Length ................857

APPENDIX 1 Guide for SafeHull Construction Monitoring Program.................... 863

APPENDIX 2 Guide for ABS Construction Monitoring Program........................... 865

vi ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

PART Chapter 1: Vessels Intended to Carry Oil in Bulk (150 meters (492 feet) or more in Length)

5C
CHAPTER 1 Vessels Intended to Carry Oil in Bulk (150 meters
(492 feet) or more in Length)

CONTENTS
SECTION 1 Introduction .......................................................................................... 13
1 General .............................................................................................13
1.1 Classification ................................................................................. 13
1.2 Optional Class Notation for Design Fatigue Life............................ 13
1.3 Application..................................................................................... 13
1.5 Internal Members .......................................................................... 14
1.7 Breaks ........................................................................................... 15
1.9 Variations ...................................................................................... 15
1.11 Loading Guidance ......................................................................... 15
1.13 Pressure-Vacuum Valve Setting.................................................... 15
1.15 Protection of Structure................................................................... 16
1.17 Aluminum Paint ............................................................................. 16
3 Special Requirements for Deep Loading ..........................................16
3.1 General.......................................................................................... 16
3.3 Machinery Casings ........................................................................ 16
3.5 Access........................................................................................... 16
3.7 Hatchways..................................................................................... 16
3.9 Freeing Arrangements................................................................... 16
3.11 Flooding......................................................................................... 16
3.13 Ventilators ..................................................................................... 16
5 Arrangement .....................................................................................17
5.1 General.......................................................................................... 17
5.3 Subdivision .................................................................................... 17
5.5 Cofferdams.................................................................................... 17
5.7 Gastight Bulkheads ....................................................................... 17
5.9 Cathodic Protection ....................................................................... 17
5.11 Ports in Pump Room Bulkheads.................................................... 18
5.13 Location of Cargo Oil Tank Openings ........................................... 18
5.15 Structural Fire Protection............................................................... 18
5.17 Allocation of Spaces ...................................................................... 18
5.19 Access to Upper Parts of Ballast Tanks on Double Hull
Tankers ......................................................................................... 18
5.21 Access to All Spaces in the Cargo Area ........................................ 19
5.23 Duct Keels or Pipe Tunnels in Double Bottom............................... 19
5.25 Ventilation...................................................................................... 19
5.27 Pumping Arrangements................................................................. 19
5.29 Electrical Equipment...................................................................... 19

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 1

 5.31 Testing...........................................................................................19
5.33 Machinery Spaces .........................................................................19

FIGURE 1.......................................................................................................15

SECTION 2 Design Considerations and General Requirements .......................... 20

1 General Requirements......................................................................20
1.1 General..........................................................................................20
1.3 Initial Scantling Requirements .......................................................20
1.5 Strength Assessment – Failure Modes ..........................................20
1.7 Structural Redundancy and Residual Strength..............................20
3 Nominal Design Corrosion Values (NDCV) ......................................21
3.1 General..........................................................................................21

TABLE 1 Nominal Design Corrosion Values (NDCV) ............................23

FIGURE 1 Nominal Design Corrosion Values (NDCV) ............................22

SECTION 3 Load Criteria ......................................................................................... 24

1 General .............................................................................................24
1.1 Load Components .........................................................................24
3 Static Loads ......................................................................................24
3.1 Still-water Bending Moment ...........................................................24
5 Wave-induced Loads ........................................................................26
5.1 General..........................................................................................26
5.3 Horizontal Wave Bending Moment and Shear Force.....................26
5.5 External Pressures ........................................................................26
5.7 Internal Pressures – Inertia Forces and Added Pressure
Heads ............................................................................................28
7 Nominal Design Loads......................................................................45
7.1 General..........................................................................................45
7.3 Hull Girder Loads – Longitudinal Bending Moments and Shear
Forces............................................................................................45
7.5 Local Loads for Design of Supporting Structures ..........................45
7.7 Local Pressures for Design of Plating and Longitudinals...............46
9 Combined Load Cases .....................................................................46
9.1 Combined Load Cases for Structural Analysis ..............................46
9.3 Combined Load Cases for Failure Assessment.............................46
11 Sloshing Loads .................................................................................47
11.1 General..........................................................................................47
11.3 Strength Assessment of Tank Boundary Structures ......................47
11.5 Sloshing Pressures........................................................................48
13 Impact Loads ....................................................................................57
13.1 Impact Loads on Bow ....................................................................57
13.3 Bottom Slamming ..........................................................................58
13.5 Bowflare Slamming........................................................................60

2 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

 TABLE 1A Combined Load Cases for Yielding and Buckling Strength
Formulation .............................................................................38
TABLE 1B Combined Load Cases for Fatigue Strength Formulation ......39
TABLE 2 Load Cases for Sloshing.........................................................40
TABLE 3 Design Pressure for Local and Supporting Members .............41
TABLE 4 Values of α ..............................................................................59
TABLE 5 Values of Ai and Bi ..................................................................62

FIGURE 1 Loading Pattern.......................................................................25

FIGURE 2 Distribution Factor mh ..............................................................33
FIGURE 3 Distribution Factor fh ................................................................33
FIGURE 4 Distribution of hdi .....................................................................34
FIGURE 5 Pressure Distribution Function klo ...........................................34
FIGURE 6 Illustration of Determining Total External Pressure ................35
FIGURE 7 Definition of Tank Geometry ...................................................36
FIGURE 8 Location of Tank for Nominal Pressure Calculation................37
FIGURE 9 Vertical Distribution of Equivalent Slosh Pressure
Head, he ...................................................................................52
FIGURE 10 Horizontal Distribution of Simultaneous Slosh Pressure
Heads, hc (φs θs) or ht (φs θs)......................................................53
FIGURE 11 Definitions for Opening Ratio, α ..............................................54
FIGURE 12 Opening Ratios .......................................................................54
FIGURE 13 Dimensions of Internal Structures...........................................55
FIGURE 14 Loading Patterns for Sloshing Loads Cases...........................56
FIGURE 15 Definition of Bow Geometry ....................................................58
FIGURE 16 Distribution of Bottom Slamming Pressure Along the
Section Girth ...........................................................................60
FIGURE 17 Definition of Bowflare Geometry for Bowflare Shape
Parameter ...............................................................................63
FIGURE 18 Ship Stem Angle, γ..................................................................64

SECTION 4 Initial Scantling Criteria ....................................................................... 65

1 General .............................................................................................65
1.1 Strength Requirement ................................................................... 65
1.3 Calculation of Load Effects............................................................ 65
1.5 Structural Details ........................................................................... 65
1.7 Evaluation of Grouped Stiffeners................................................... 65
3 Hull Girder Strength ..........................................................................69
3.1 Hull Girder Section Modulus.......................................................... 69
3.3 Hull Girder Moment of Inertia ........................................................ 69
5 Shearing Strength .............................................................................69
5.1 General.......................................................................................... 69
5.3 Net Thickness of Side Shell Plating............................................... 70
5.5 Thickness of Longitudinal Bulkheads ............................................ 70
5.7 Calculation of Local Loads ............................................................ 72
5.9 Three Dimensional Analysis .......................................................... 74

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 3

 7 Double Bottom Structures.................................................................75
7.1 General..........................................................................................75
7.3 Bottom Shell and Inner Bottom Plating ..........................................75
7.5 Bottom and Inner Bottom Longitudinals.........................................78
7.7 Bottom Girders/Floors....................................................................79
9 Side Shell and Deck – Plating and Longitudinals .............................86
9.1 Side Shell Plating...........................................................................86
9.3 Deck Plating ..................................................................................88
9.5 Deck and Side Longitudinals .........................................................90
11 Side Shell and Deck – Main Supporting Members ...........................92
11.1 General..........................................................................................92
11.3 Deck Transverses..........................................................................92
11.5 Deck Girders..................................................................................95
11.7 Web Sectional Area of Side Transverses ......................................96
11.9 Minimum Thickness for Web Portion of Main Supporting
Members........................................................................................97
11.11 Proportions ....................................................................................97
11.13 Brackets.........................................................................................98
11.15 Web Stiffeners and Tripping Brackets ...........................................98
11.17 Slots and Lightening Holes ............................................................99
13 Longitudinal and Transverse Bulkheads.........................................100
13.1 Longitudinal Bulkhead Plating .....................................................100
13.3 Transverse Bulkhead Plating.......................................................102
13.5 Longitudinals and Vertical/Horizontal Stiffeners ..........................103
15 Bulkheads – Main Supporting Members.........................................105
15.1 General........................................................................................105
15.3 Vertical Web on Longitudinal Bulkhead .......................................105
15.5 Horizontal Girder on Transverse Bulkhead..................................107
15.7 Vertical Web on Transverse Bulkhead.........................................109
15.9 Minimum Web Thickness, Proportions, Brackets, Stiffeners,
Tripping Brackets, Slots and Lightening Holes ............................110
15.11 Cross Ties ...................................................................................110
15.13 Nontight Bulkheads......................................................................111
17 Corrugated Bulkheads ....................................................................111
17.1 General........................................................................................111
17.3 Plating..........................................................................................111
17.5 Stiffness of Corrugation ...............................................................112
17.7 Bulkhead Stools...........................................................................115
17.9 End Connections .........................................................................116

TABLE 1 Coefficient c2 For Deck Transverses.....................................100

TABLE 2 Coefficients KU and KL for Side Transverses ........................100
TABLE 3 Coefficient c for Vertical Web on Longitudinal Bulkheads ....107
TABLE 4 Coefficients KU and KL for Vertical Web on Longitudinal
Bulkhead ...............................................................................107

FIGURE 1 Scantling Requirement Reference by Subsection ..................66

FIGURE 2A Definitions of Spans (A) ..........................................................67

4 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

 FIGURE 2B Definitions of Spans (B) ..........................................................68
FIGURE 3 Center Tank Region................................................................74
FIGURE 4.......................................................................................................75
FIGURE 5 Unsupported Span of Longitudinal .........................................83
FIGURE 6 Effective Breadth of Plating be .................................................84
FIGURE 7 Definitions of α3, ls and bs ........................................................85
FIGURE 8 Effectiveness of Brackets........................................................99
FIGURE 9 Definition of Parameters for Corrugated Bulkhead
(Tankers without Longitudinal Bulkhead at Centerline) ........117
FIGURE 10 Definition of Parameters for Corrugated Bulkhead
(Tankers with Longitudinal Bulkhead at Centerline) .............118
FIGURE 11 Corrugated Bulkhead End Connections ...............................119

SECTION 5 Total Strength Assessment............................................................... 120

1 General Requirements....................................................................120
1.1 General........................................................................................ 120
1.3 Loads and Load Cases ............................................................... 120
1.5 Stress Components ..................................................................... 120
3 Failure Criteria – Yielding................................................................121
3.1 General........................................................................................ 121
3.3 Structural Members and Elements .............................................. 121
3.5 Plating ......................................................................................... 122
5 Failure Criteria – Buckling and Ultimate Strength...........................122
5.1 General........................................................................................ 122
5.3 Plate Panels ................................................................................ 123
5.5 Longitudinals and Stiffeners ........................................................ 125
5.7 Stiffened Panels .......................................................................... 126
5.9 Deep Girders and Webs .............................................................. 126
5.11 Corrugated Bulkheads................................................................. 127
5.13 Hull Girder Ultimate Strength....................................................... 128
7 Fatigue Life .....................................................................................130
7.1 General........................................................................................ 130
7.3 Procedures .................................................................................. 130
7.5 Spectral Analysis......................................................................... 131
9 Calculation of Structural Responses...............................................131
9.1 Methods of Approach and Analysis Procedures.......................... 131
9.3 3D Finite Element Models ........................................................... 132
9.5 2D Finite Element Models ........................................................... 132
9.7 Local Structural Models ............................................................... 132
9.9 Load Cases ................................................................................. 132
11 Critical Areas...................................................................................132

FIGURE 1.....................................................................................................129
FIGURE 2 Critical Areas in Transverse Web Frame..............................133
FIGURE 3 Critical Areas in Horizontal Girder on Transverse
Bulkhead ...............................................................................133
FIGURE 4 Critical Areas of Buttress Structure.......................................133

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 5

 SECTION 6 Hull Structure Beyond 0.4L Amidships .............................................. 134
1 General Requirements....................................................................134
1.1 General........................................................................................134
1.3 Structures within the Cargo Space Length ..................................134
3 Forebody Side Shell Structure ........................................................134
3.1 Side shell Plating .........................................................................134
3.3 Side Frames and Longitudinals ...................................................136
3.5 Side Transverses and Stringers in Forebody...............................137
5 Transition Zone ...............................................................................144
7 Forebody Strengthening for Slamming ...........................................145
7.1 Bottom Slamming ........................................................................145
7.3 Bowflare Slamming......................................................................146

FIGURE 1 Transverse Distribution of pd .................................................137

FIGURE 2 Definition of Spans ................................................................144

SECTION 7 Cargo Oil and Associated Systems .................................................. 148

1 General ...........................................................................................148
1.1 Application ...................................................................................148
1.3 Definitions....................................................................................148
1.5 Plans and Data to be Submitted ..................................................149
1.7 Some General Principles .............................................................150
1.9 Cargo Oil Having a Flash Point Exceeding 60°C.........................151
3 Cargo Oil, Stripping and Crude Oil Washing Systems ...................152
3.1 General........................................................................................152
3.3 Cargo Oil System.........................................................................152
3.5 Remotely Operated Valves..........................................................155
5 Ballast System and Oily Water Handling ........................................155
5.1 Segregated Ballast ......................................................................155
5.3 Ballast System .............................................................................155
7 Bilge System ...................................................................................157
7.1 General........................................................................................157
7.3 Pump Room and Cofferdams Bilge System ................................157
7.5 Bilge Alarms ................................................................................157
7.7 Discharge of Machinery Space Bilges into Slop Tank .................157
9 Cargo Heating Systems ..................................................................158
9.1 Temperature ................................................................................158
9.3 Steam Heating System ................................................................158
9.5 Thermal Oil Heating System ........................................................158
11 Cargo Tank Venting ........................................................................159
11.1 General Principles .......................................................................159
11.3 Venting Capacity..........................................................................159
11.5 Vent Piping ..................................................................................159
11.7 Self-draining of Vent Piping .........................................................159
11.9 Flame Arresting Devices..............................................................160
11.11 Protection for Tank Overpressurization and Vacuum ..................160

6 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

 11.13 Position of Pressure/Vacuum Valves .......................................... 160
11.15 Pressure/Vacuum Valve By-pass ................................................ 161
11.17 Vent Outlets for Large Flow Volumes .......................................... 161
11.19 Arrangement for Combination Carriers........................................ 161
13 Cargo Tank Level Gauging .............................................................161
13.1 Cargo Tanks Fitted with Inert Gas System .................................. 161
13.3 Cargo Tanks not Fitted with Inert Gas System ............................ 161
15 Cargo Tank Purging and/or Gas-freeing.........................................161
15.1 General........................................................................................ 161
15.3 Vessels Fitted with Inert Gas System .......................................... 162
15.5 Vessels without Inert Gas System............................................... 162
17 Ventilation and Gas Detection ........................................................162
17.1 Cargo Pump Room Ventilation .................................................... 162
17.3 Precautions for Ventilation of Accommodation and Machinery
Spaces ........................................................................................ 163
17.5 Pipe Tunnel or Duct Keel Ventilation........................................... 163
17.7 Portable Gas Detectors ............................................................... 164
17.9 Gas Sampling System Installation............................................... 164
17.11 Ventilation for Combination Carriers............................................ 164
19 Double Hull Space Inerting, Ventilation and Gas Measurement ....164
19.1 Air Supply .................................................................................... 164
19.3 Vessels Fitted with Inert Gas System .......................................... 164
19.5 Provisions for Gas Measurement ................................................ 165
20 Fixed Hydrocarbon Gas Detection System.....................................165
20.1 Application................................................................................... 165
20.3 Engineering Specification ............................................................ 165
20.5 Component Requirements........................................................... 166
21 Cargo Vapor Emission Control Systems ........................................167
21.1 Application................................................................................... 167
21.3 Plans and Data to be Submitted.................................................. 167
21.5 Cargo Transfer Rate.................................................................... 167
21.7 Vapor Collection Piping ............................................................... 169
21.9 Ship Side Vapor Connection ....................................................... 169
21.11 Pressure/Vacuum Protection of Cargo Tanks ............................. 169
21.13 Gauging Systems ........................................................................ 170
21.15 Tank Overfill Protection ............................................................... 170
21.17 Electrical Installations .................................................................. 171
21.19 Vapor Collection for Lightering Operations.................................. 171
21.21 Instruction Manual ....................................................................... 171
23 Cargo Tank Protection ....................................................................172
23.1 Inert Gas System and Deck Foam System.................................. 172
23.3 Crude Oil Washing ...................................................................... 172
23.5 Fire Main Isolation Valve ............................................................. 172
23.7 Fireman’s Outfits ......................................................................... 172
25 Inert Gas System ............................................................................172
25.1 General........................................................................................ 172
25.3 Basic Requirements .................................................................... 173
25.5 System Capacity and Oxygen Content........................................ 173

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 7

 25.7 Source of Inert Gas......................................................................173
25.9 Flue Gas Isolating Valves ............................................................173
25.11 Flue Gas Scrubber.......................................................................174
25.13 Blowers........................................................................................174
25.15 Flue Gas Leakage .......................................................................175
25.17 Gas Regulating Valve ..................................................................175
25.19 Non-return Devices......................................................................175
25.21 Branching of Inert Gas Main ........................................................176
25.23 Venting for Large Gas Volumes...................................................176
25.25 Inerting, Purging or Gas-freeing of Empty Tanks.........................176
25.27 Pressure/Vacuum-breaking Devices............................................177
25.29 Instrumentation at Gas Blower Outlets ........................................178
25.31 Monitoring of Inert Gas ................................................................178
25.33 Portable Detectors .......................................................................178
25.35 Calibration of Instruments............................................................178
25.37 Alarms and Shutdowns................................................................178
25.39 Instruction Manuals......................................................................179
25.41 Nitrogen Generator Inert Gas Systems........................................180
27 Fixed Deck Foam System...............................................................182
27.1 General........................................................................................182
27.3 Foam Solution Supply Rate .........................................................182
27.5 Foam Concentrate Quantity.........................................................182
27.7 Required Foam Monitor and Foam Applicator Capacities ...........182
27.9 Minimum Foam Monitor Capacity ................................................182
27.11 Installation at Poop Front.............................................................183
27.13 Use and Minimum Capacity of Foam Applicators ........................183
27.15 Foam Main and Fire Main Isolation Valves..................................183
27.17 Simultaneous Operation ..............................................................183
27.19 Bow or Stern Loading and Unloading ..........................................183
29 Cargo Pump Room Protection ........................................................183
29.1 Fixed Fire Extinguishing System..................................................183
29.3 Required Quantity of Fire-extinguishing Medium .........................183
31 Electrical Installations .....................................................................184
31.1 Application ...................................................................................184
31.3 Limited Use of Earthed Distribution Systems...............................184
31.5 Hazardous Areas .........................................................................184
31.7 Air Locks......................................................................................186
31.9 Electrical Equipment Permitted in Hazardous Areas ...................187
31.11 Cable Installation in Hazardous Areas.........................................187
31.13 Echo Sounder; Speed Log; Impressed Current System ..............188
31.15 Cargo Oil Pump Room.................................................................188
31.17 Pipe Tunnel or Duct Keel.............................................................189
33 Integrated Cargo and Ballast Systems ...........................................189
33.1 Application ...................................................................................189
33.3 Functional Requirements.............................................................189
33.5 Design Features ..........................................................................189

8 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

 TABLE 1 Electrical Equipment in Hazardous Areas of Oil Carriers .....187

FIGURE 1 Connection between Inert Gas Main and Cargo Piping .......177
FIGURE 2 Hazardous Areas on Open Deck ..........................................186

APPENDIX 1 Guide for Fatigue Strength Assessment of Tankers....................... 190

1 General ...........................................................................................190
1.1 Note............................................................................................. 190
1.3 Applicability ................................................................................. 190
1.5 Loadings...................................................................................... 190
1.7 Effects of Corrosion..................................................................... 190
1.9 Format of the Criteria .................................................................. 191
3 Connections to be Considered for the Fatigue Strength
Assessment ....................................................................................191
3.1 General........................................................................................ 191
3.3 Guidance on Locations................................................................ 191
5 Permissible Stress Range...............................................................198
5.1 Assumptions................................................................................ 198
5.3 Criteria......................................................................................... 198
5.5 Long Term Stress Distribution Parameter, γ ................................ 198
5.7 Permissible Stress Range ........................................................... 199
7 Fatigue Inducing Loads and Determination of Total Stress
Ranges............................................................................................202
7.1 General........................................................................................ 202
7.3 Wave-induced Loads – Load Components.................................. 202
7.5 Fatigue Assessment Zones and Controlling Load
Combination ................................................................................ 202
7.7 Primary Stress fd1 ........................................................................ 203
7.9 Secondary Stress fd2 .................................................................... 203
7.11 Additional Secondary Stresses f*d2 and Tertiary Stresses fd3 ...... 203
9 Resulting Stress Ranges ................................................................206
9.1 Definitions.................................................................................... 206
11 Determination of Stress Concentration Factors (SCFs) .................207
11.1 General........................................................................................ 207
11.3 Sample Stress Concentration Factors (SCFs)............................. 207
13 Stress Concentration Factors Determined From Finite Element
Analysis...........................................................................................214
13.1 Introduction.................................................................................. 214
13.3 S-N Data...................................................................................... 214
13.5 S-N Data and SCFs..................................................................... 214
13.7 Calculation of Hot Spot Stress for Fatigue Analysis of Ship
Structures .................................................................................... 217

TABLE 1 Fatigue Classification for Structural Details ..........................193

TABLE 1A Coefficient, C.........................................................................199
TABLE 2 Ks (SCF) Values ....................................................................207

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 9

 FIGURE 1 Basic Design S-N Curves .....................................................200
FIGURE 2 Cn = Cn (ψ) .............................................................................205
FIGURE 3 Cut-outs (Slots) For Longitudinal ..........................................209
FIGURE 4 Fatigue Classification for Longitudinals in way of Flat Bar
Stiffener.................................................................................211
FIGURE 5.....................................................................................................211
FIGURE 6.....................................................................................................212
FIGURE 7.....................................................................................................212
FIGURE 8.....................................................................................................213
FIGURE 9 Doublers and Non-load Carrying Members on Deck or
Shell Plating ..........................................................................213
FIGURE 10...................................................................................................216
FIGURE 11...................................................................................................216
FIGURE 12...................................................................................................216
FIGURE 13...................................................................................................218

APPENDIX 2 Calculation of Critical Buckling Stresses......................................... 219

1 General ...........................................................................................219
3 Rectangular Plates..........................................................................219
5 Longitudinals and Stiffeners............................................................222
5.1 Axial Compression.......................................................................222
5.3 Torsional/Flexural Buckling..........................................................222
5.5 Buckling Criteria for Unit Corrugation of Transverse
Bulkhead......................................................................................223
7 Stiffened Panels..............................................................................225
7.1 Large Stiffened Panels ................................................................225
7.3 Corrugated Transverse Bulkheads ..............................................226
9 Deep Girders, Webs and Stiffened Brackets ..................................227
9.1 Critical Buckling Stresses of Web Plates and Large Brackets .....227
9.3 Effects of Cut-outs .......................................................................227
9.5 Tripping........................................................................................227
11 Stiffness and Proportions................................................................228
11.1 Stiffness of Longitudinals.............................................................228
11.3 Stiffness of Web Stiffeners ..........................................................229
11.5 Stiffness of Supporting Members.................................................229
11.7 Proportions of Flanges and Face Plates......................................229
11.9 Proportions of Webs of Longitudinals and Stiffeners ...................229

TABLE 1 Buckling Coefficient, Ki .........................................................220

FIGURE 1 Net Dimensions and Properties of Stiffeners........................224

FIGURE 2.....................................................................................................226

10 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

 APPENDIX 3 Application to Single Hull Tankers ................................................... 230
1 General ...........................................................................................230
1.1 Nominal Design Corrosion Values............................................... 230
1.3 Load Criteria................................................................................ 230
1.5 Strength Criteria .......................................................................... 230
3 Main Supporting Structures ............................................................231
3.1 Bottom Transverses .................................................................... 231
3.3 Bottom Girders ............................................................................ 232
3.5 Side Transverses ........................................................................ 235
3.7 Deck Transverses ....................................................................... 236
3.9 Longitudinal Bulkhead Vertical Webs .......................................... 238
3.11 Other Main Supporting Members ................................................ 240
3.13 Proportions .................................................................................. 240
5 Strength Assessment......................................................................240
5.1 General........................................................................................ 240
5.3 Special Considerations................................................................ 240

TABLE 1 Design Pressure for Local and Supporting Structures..........233

TABLE 2 Coefficient c for Side Transverse ..........................................235
TABLE 3 Coefficients KU and KL for Side Transverses ........................236
TABLE 4 Coefficient c2 For Deck Transverse.......................................238
TABLE 5 Coefficient c for Vertical Web on Longitudinal Bulkhead ......239
TABLE 6 Coefficients KU and KL for Vertical Web on Longitudinal
Bulkhead ...............................................................................240

FIGURE 1 Spans of Transverses and Girders .......................................234

APPENDIX 4 Application to Mid-deck Tankers ...................................................... 241

1 General ...........................................................................................241
1.1 Design Concepts ......................................................................... 241
1.3 Design and Strength of Hull Structures ....................................... 241
3 Load Criteria ...................................................................................242
3.1 Loading Patterns and Load Cases .............................................. 242
3.3 Determination of Loads and Scantlings ....................................... 243
5 Strength Criteria..............................................................................244
5.1 Hull Girder and Structural Elements ............................................ 244
5.3 Mid-deck Structures .................................................................... 244
7 Strength Assessment......................................................................244
7.1 Failure Criteria............................................................................. 244
7.3 Special Considerations................................................................ 244

FIGURE 1 Typical Cross Section for Mid-deck Tankers ........................242

FIGURE 2 Loading Pattern.....................................................................243

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 11

 APPENDIX 5 Guide for Hull Girder Ultimate Strength Assessment of Oil
Carriers................................................................................................ 245
1 General ...........................................................................................245
3 Vertical Hull Girder Ultimate Limit State .........................................245
5 Hull Girder Ultimate Bending Moment Capacity .............................246
5.1 General........................................................................................246
5.3 Physical Parameters....................................................................247
5.5 Calculation Procedure .................................................................248
5.7 Assumptions and Modeling of the Hull Girder Cross-section.......249
5.9 Stress-strain Curves σ-ε (or Load-end Shortening Curves) .........251

FIGURE 1 Bending Moment – Curvature Curve M-κ .............................246

FIGURE 2 Dimensions and Properties of Stiffeners ..............................248
FIGURE 3 Example of Defining Structural Elements .............................250
FIGURE 4 Example of Stress Strain Curves σ-ε ....................................251

12 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

PART Section 1: Introduction

5C
CHAPTER 1 Vessels Intended to Carry Oil in Bulk (150 meters
(492 feet) or more in Length)

SECTION 1 Introduction

1 General

1.1 Classification (1 July 2001)

In accordance with 1-1-3/3 and 1-1-3/25, the classification notation À A1 Oil Carrier, SH, SHCM is to
be assigned to vessels designed for the carriage of oil cargoes in bulk, and built to the requirements of this
Chapter and other relevant sections of the Rules. As used in the Rules, the term ‘‘oil’’ refers to petroleum
products having flash points at or below 60°C (140°F), closed cup test, and specific gravity of not over
1.05. Vessels intended to carry fuel oil having a flash point above 60°C (140°F), closed cup test, and to
receive classification À A1 Fuel Oil Carrier, SH, SHCM are to comply with the requirements of this
Chapter and other relevant sections of the Rules, with the exception that the requirements for cofferdams,
gastight bulkheads and aluminum paint may be modified.

1.2 Optional Class Notation for Design Fatigue Life (2003)

Vessels designed and built to the requirements in this Chapter are intended to have a structural fatigue life
of not less than 20 years. Where a vessel’s design calls for a fatigue life in excess of the minimum design
fatigue life of 20 years, the optional class notation FL (year) will be assigned at the request of the
applicant. This optional notation is eligible, provided the excess design fatigue life is verified to be in
compliance with the criteria in Appendix 1 of this Chapter, “Guide for Fatigue Strength Assessment of
Tankers.” Only one design fatigue life value is published for the entire structural system. Where differing
design fatigue life values are intended for different structural elements within the vessel, the (year) refers
to the least of the varying target lives. The ‘design fatigue life’ refers to the target value set by the
applicant, not the value calculated in the analysis.
The notation FL (year) denotes that the design fatigue life assessed according to Appendix 1 of this
Chapter is greater than the minimum design fatigue life of 20 years. The (year) refers to the fatigue life
equal to 25 years or more (in 5-year increments) as specified by the applicant. The fatigue life will be
identified in the Record by the notation FL (year); e.g., FL(30) if the minimum design fatigue life
assessed is 30 years.

1.3 Application
1.3.1 Size and Proportion (1997)
The requirements contained in this Chapter are applicable to double hull tankers intended for
unrestricted service, having lengths of 150 meters (492 feet) or more, and having parameters
within the range as specified in 3-2-1/1.
1.3.2 Vessel Types
The equations and formulae for determining design load and strength requirements, as specified in
Section 5C-1-3 and Section 5C-1-4, are applicable to double hull tankers. For mid-deck or single
hull tankers, the parameters used in the equations are to be adjusted according to the structural
configurations and loading patterns outlined in Appendix 5C-1-A3 or Appendix 5C-1-A4. The
strength assessment procedures and the failure criteria, as specified in Section 5C-1-5, are applicable
to all types of tankers.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 13

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 1 Introduction 5C-1-1

Double hull tanker is a tank vessel having full depth wing water ballast tanks or other non-cargo
spaces, and full breadth double bottom water ballast tanks or other non-cargo spaces throughout
the cargo area, intended to prevent or at least reduce the liquid cargo outflow in an accidental
stranding or collision. The size and capacity of these wing/double bottom tanks or spaces are to
comply with MARPOL 73/78 and national Regulations, as applicable.
Mid-deck tanker: Refer to 5C-1-A4/1.1, “Design Concepts”.
Single hull tanker is a tank vessel that does not fit the above definitions of Double hull tanker or
Mid-deck tanker.
1.3.3 Direct Calculations
Direct calculations with respect to the determination of design loads and the establishment of
alternative strength criteria based on first principles will be accepted for consideration, provided
that all the supporting data, analysis procedures and calculated results are fully documented and
submitted for review. In this regard, due consideration is to be given to the environmental
conditions, probability of occurrence, uncertainties in load and response predictions and reliability
of the structure in service. For long term prediction of wave loads, realistic wave spectra covering
the North Atlantic Ocean and a probability level of 10-8 are to be employed.
1.3.4 SafeHull Construction Monitoring Program (1 July 2001)
For the class notation SH, SHCM, a Construction Monitoring Plan for critical areas, prepared in
accordance with the requirements of Part 5C, Appendix 1, is to be submitted for approval prior to
commencement of fabrication. See Part 5C, Appendix 1 “Guide for SafeHull Construction Monitoring
Program”.

1.5 Internal Members (2002)

1.5.1 Section Properties of Structural Members (1 July 2008)
The geometric properties of structural members may be calculated directly from the dimensions of
the section and the associated effective plating (see 3-1-2/13.3 or 5C-1-4/Figure 6, as applicable).
For structural member with angle θ (see 5C-1-1/Figure 1) between web and associated plating not
less than 75 degrees, the section modulus, web sectional area and moment of inertia of the
“standard” (θ = 90 degrees) section may be used without modification. Where the angle θ is less
than 75 degrees, the sectional properties are to be directly calculated about an axis parallel to the
associated plating (see 5C-1-1/Figure 1).
For longitudinals, frames and stiffeners, the section modulus may be obtained by the following
equation:
SM = αθSM90
where
αθ = 1.45 – 40.5/θ
SM90 = the section modulus at θ = 90 degrees
The effective section area may be obtained from the following equation:
A = A90 sin θ
where
A90 = effective shear area at θ = 90 degrees

1.5.2 Detailed Design

The detailed design of internals is to follow the guidance given in 3-1-2/15 and 5C-1-4/1.5.
See also Appendix 5C-1-A1 “Guide for Fatigue Strength Assessment of Tankers”.

14 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 1 Introduction 5C-1-1

FIGURE 1

dw

θ = 90°

Standard

dw

1.7 Breaks
Special care is to be taken to provide against local stresses at the ends of the cargo oil spaces, superstructures,
etc., and throughout the structure in general. The main longitudinal bulkheads are to be suitably tapered at
their ends, and effective longitudinal bulkheads in the poop are to be located such as to provide effective
continuity between the structure in way of and beyond the main cargo spaces. Where the break of a
superstructure lies within the midship 0.5L, the required shell and deck scantlings for the amidship 0.4L
may be required to be extended to effect a gradual taper of the structure, and the deck stringer plate and
sheer strake are to be increased. See 5C-1-4/9.1 and 5C-1-4/9.3. Where the breaks of the forecastle or poop
are appreciably beyond the amidship 0.5L, the requirements for the deck stringer plate and sheer strake, as
specified in 5C-1-4/9.1 and 5C-1-4/9.3, may be modified.

1.9 Variations
Tankers of a special type or design, differing from those described in these Rules, will be specially considered
on the basis of equivalent strength.

1.11 Loading Guidance (1997)

Loading guidance is to be as required by 3-2-1/7, except that 5C-1-4/5 will apply for allowable shear stresses.

1.13 Pressure-Vacuum Valve Setting (1993)

Where pressure-vacuum valves of cargo oil tanks are set at a pressure in excess of the pressure appropriate
to the length of the vessel (see 5C-1-7/11.11.2), the tank scantlings will be specially considered.
Particular attention is to be given to a higher pressure setting of pressure-vacuum valves as may be required
for the efficient operation of cargo vapor emission control systems, where installed.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 15

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 1 Introduction 5C-1-1

1.15 Protection of Structure

For the protection of structure, see 3-2-18/5.

1.17 Aluminum Paint

Paint containing aluminum is not to be used in cargo tanks, on tank decks in way of cargo tanks, and in
pump rooms and cofferdams, nor in any other area where cargo vapor may accumulate, unless it has been
shown by appropriate tests that the paint to be used does not increase the fire hazard.

3 Special Requirements for Deep Loading

3.1 General (2003)

Where a vessel is intended to operate at the minimum freeboard allowed by the International Convention
on Load Lines, 1966 for Type-A vessels, the conditions in 5C-1-1/3.3 through 5C-1-1/3.11 are to be
complied with.

3.3 Machinery Casings

Machinery casings are normally to be protected by an enclosed poop or bridge, or by a deckhouse of
equivalent strength. The height of such structure is to be not less than 2.3 m (7.5 ft). The bulkheads at the
forward ends of these structures are to have scantlings not less than required for bridge-front bulkheads
(See 3-2-11/3). Machinery casings may be exposed, provided that they are specially stiffened and there are
no openings giving direct access from the freeboard deck to the machinery space. A door complying with
the requirements of 3-2-11/5.3 may, however, be permitted in the exposed machinery casing, provided that
it leads to a space or passageway which is as strongly constructed as the casing and is separated from the
engine room by a second door complying with 3-2-11/5.3. The sill of the exterior door is not to be less than
600 mm (23.5 in.), and the sill of the second door is not to be less than 230 mm (9 in.).

3.5 Access (1998)

Satisfactory arrangements are to be provided to safeguard the crew in reaching all areas used in the
necessary work of the vessel. See 3-2-17/3.

3.7 Hatchways
Exposed hatchways on the freeboard and forecastle decks or on the tops of expansion trunks are to be
provided with efficient steel watertight covers. The use of material other than steel will be subject to
special consideration.

3.9 Freeing Arrangements

Tankers with bulwarks are to have open rails fitted for at least half the length of the exposed parts of the
freeboard and superstructure decks, or other effective freeing arrangements are to be provided. The upper
edge of the sheer strake is to be kept as low as practicable. Where superstructures are connected by trunks,
open rails are to be fitted for the entire length of the exposed parts of the freeboard deck.

3.11 Flooding (2003)

Attention is called to the requirement of the International Convention on Load Lines, 1966, that tankers
over 150 m (492 ft) in freeboard length (see 3-1-1/3.3), to which freeboards less than those based solely on
Table B are assigned, must be able to withstand the flooding of certain compartments.

3.13 Ventilators (2003)

Ventilators to spaces below the freeboard deck are to be specially stiffened or protected by superstructures
or other efficient means. See also 3-2-17/9.

16 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 1 Introduction 5C-1-1

5 Arrangement (1994)

5.1 General
The arrangements of the vessel are to comply with the requirements in Annex 1 to the International
Convention for the Prevention of Pollution from Ships with regard to segregated ballast tanks (Regulation 13),
their protective locations (Regulation 13E – where the option in Regulation 13F (4) or (5) is exercised),
collision or stranding considerations (Regulation 13F), hypothetical outflow of oil (Regulation 23), limitations
of size and arrangement of cargo tanks (Regulation 24) and slop tanks [Regulation 15 (2) (c)]. A valid
International Oil Pollution Prevention Certificate issued by the flag administration may be accepted as
evidence of compliance with these requirements.

5.3 Subdivision
The length of tanks, the location of expansion trunks and the position of longitudinal bulkheads are to be
arranged to avoid excessive dynamic stresses in the hull structure.

5.5 Cofferdams
Cofferdams, thoroughly oiltight and vented, and having widths as required for ready access, are to be
provided in order to separate all cargo tanks from galleys and living quarters, general cargo spaces which
are below the uppermost continuous deck, boiler rooms and spaces containing propulsion machinery or
other machinery where sources of ignition are normally present. Pump rooms, compartments arranged
solely for ballast and fuel oil tanks may be considered as cofferdams for the purpose of this requirement.

5.7 Gastight Bulkheads

Gastight bulkheads are to be provided in order to isolate all cargo pumps and piping from spaces
containing stoves, boilers, propelling machinery, electric apparatus or machinery where sources of ignition
are normally present. These bulkheads are to comply with the requirements of Section 3-2-9.

5.9 Cathodic Protection (1996)

5.9.1 Anode Installation Plan
Where sacrificial anodes are fitted in cargo or adjacent ballast tanks, their material, their disposition
and details of their attachment are to be submitted for approval.
5.9.2 Magnesium and Magnesium Alloy Anodes
Magnesium and magnesium alloy anodes are not to be used.
5.9.3 Aluminum Anodes (2006)
Aluminum anodes may be used in the cargo tanks and tanks adjacent to the cargo tanks of tankers
in locations where the potential energy does not exceed 275 N-m (28 kgf-m, 200 ft-lb). The height
of the anode is to be measured from the bottom of the tank to the center of the anode, and the
weight is to be taken as the weight of the anode as fitted, including the fitting devices and inserts.
Where aluminum anodes are located on horizontal surfaces, such as bulkhead girders and stringers,
which are not less than 1 m (39 in.) wide and fitted with an upstanding flange or face flat projecting
not less than 75 mm (3 in.) above the horizontal surface, the height of the anode may be measured
from this surface.
Aluminum anodes are not to be located under tank hatches or Butterworth openings unless
protected from falling metal objects by adjacent tank structure.
5.9.4 Zinc Anodes (2006)
There is no restriction on the positioning of zinc anodes.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 17

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 1 Introduction 5C-1-1

5.9.5 Anode Attachment

Anodes are to have steel cores sufficiently rigid to avoid resonance in the anode support, and the
cores are to be designed to retain the anode even when it is wasted.
The steel cores are to be attached to the structure by means of continuous welds at least 75 mm
(3 in.) in length. Alternatively, they may be attached to separate supports by bolting. A minimum
of two bolts with locknuts is to be used.
The supports at each end of an anode are not to be attached to items of structure that are likely to
move independently.
Anode inserts and supports welded directly to the structure are to be arranged so that the welds are
clear of stress raisers.

5.11 Ports in Pump Room Bulkheads

Where fixed ports are fitted in the bulkheads between a pump room and the machinery or other safe space,
they are to maintain the gastight and watertight integrity of the bulkhead. The ports are to be effectively
protected against the possibility of mechanical damage and are to be fire resistant. Hinged port covers of
steel, having non-corrosive hinge pins and secured from the safe space side, are to be provided. The covers
are to provide strength and integrity equivalent to the unpierced bulkhead. Except where it may interfere
with the function of the ports, the covers are to be secured in the closed position. The use of material other
than steel for the covers will be subject to special consideration. Lighting fixtures providing strength and
integrity equivalent to that of the port covers will be accepted as an alternative.

5.13 Location of Cargo Oil Tank Openings

Cargo oil tank openings, including those for tank cleaning, which are not intended to be secured gastight at
all times during the normal operation of the vessel, are not to be located in enclosed spaces. For the purpose
of this requirement, spaces open on one side only are to be considered enclosed. See also 5C-1-1/5.23.

5.15 Structural Fire Protection

The applicable requirements of Section 3-4-1 are to be complied with.

5.17 Allocation of Spaces (1994)

5.17.1 Tanks Forward of the Collision Bulkhead
Tanks forward of the collision bulkhead are not to be arranged for the carriage of oil or other
liquid substances that are flammable.
5.17.2 Double Bottom Spaces and Wing Tank Spaces
For vessels of 5000 metric tons (4921 long tons) deadweight and above, double bottom spaces or
wing tanks adjacent to cargo oil tanks are to be allocated for water ballast or spaces other than
cargo and fuel oil tanks.

5.19 Access to Upper Parts of Ballast Tanks on Double Hull Tankers (1993)
Where the structural configuration within ballast tanks is such that it will prevent access to upper parts of
the tanks for required close-up examination (see 7-3-2/5.13.4) by conventional means, such as a raft on
partly filled tank, permanent means of safe access is to be provided. Details of the access are to be submitted
for review.
Where horizontal girders or diaphragm plates are fitted, they may be considered as forming part of a permanent
access. Alternative arrangements to the above may be considered upon submission.

18 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 1 Introduction 5C-1-1

5.21 Access to All Spaces in the Cargo Area (1 October 1994)

Access to cofferdams, ballast tanks, cargo tanks and other spaces in the cargo area is to be direct and from
the open deck. Access to double bottom spaces may be through a cargo pump room, deep cofferdam, pipe
tunnel or similar space, provided ventilation is suitable.
For access through horizontal openings, hatches or manholes, the access is to be of a size such as to allow a
person wearing a self-contained, air-breathing apparatus and protective equipment (see 4-7-3/15.5) to ascend
or descend any ladder without obstruction and also to provide a clear opening to facilitate the hoisting of
an injured person from the bottom of the space. In general, the minimum clear opening is not to be less
than 600 mm (24 in.) by 600 mm (24 in.).
For access through vertical openings or manholes providing passage through the length and breadth of the
space, the minimum clear opening is not to be less than 600 mm (24 in.) by 800 mm (32 in.) at a height of
not more than 600 mm (24 in.) from the bottom shell plating unless gratings or other footholds are provided.

5.23 Duct Keels or Pipe Tunnels in Double Bottom (2000)

Duct keels or pipe tunnels are not to pass into machinery spaces. Provision is to be made for at least two
exits to the open deck, arranged at a maximum distance from each other. One of these exits may lead to
the cargo pump room, provided that it is watertight and fitted with a watertight door complying with the
requirements of 3-2-9/9.1 and in addition complying with the following:
i) In addition to bridge operation, the watertight door is to be capable of being closed from outside
the main pump room entrance; and
ii) A notice is to be affixed at each operating position to the effect that the watertight door is to be
kept closed during normal operations of the vessel, except when access to the pipe tunnel is required.
For the requirements of ventilation and gas detection in duct keels or pipe tunnels, see 5C-1-7/31.17.1.

5.25 Ventilation (1996)

Holes are to be cut in every part of the structure where otherwise there might be a chance of gases being
“pocketed”. Special attention is to be paid to the effective ventilation of pump rooms and other working
spaces adjacent to oil tanks. In general, floor plating is to be of an open type not to restrict the flow of air,
see 5C-1-7/17.1 and 5C-1-7/17.5. Efficient means are to be provided for clearing the oil spaces of dangerous
vapors by means of artificial ventilation or steam. For cargo tank venting, see 5C-1-7/11 and 5C-1-7/21.

5.27 Pumping Arrangements

See applicable requirements in Section 5C-1-7.

5.29 Electrical Equipment

See 5C-1-7/31.

5.31 Testing
Requirements for testing are contained in Part 3, Chapter 7.

5.33 Machinery Spaces

Machinery spaces aft are to be specially stiffened transversely. Longitudinal material at the break is also to
be specially considered to reduce concentrated stresses in this region. Longitudinal wing bulkheads are to
be incorporated with the machinery casings or with substantial accommodation bulkheads in the tween
decks and within the poop.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 19

PART Section 2: Design Considerations and General Requirements

5C
CHAPTER 1 Vessels Intended to Carry Oil in Bulk (150 meters
(492 feet) or more in Length)

SECTION 2 Design Considerations and General Requirements

1 General Requirements (1995)

1.1 General (1995)

The strength requirements specified in this Chapter are based on a “net” ship approach. In determining the
required scantlings and performing structural analyses and strength assessments, the nominal design
corrosion values given in 5C-1-2/Table 1 are to be deducted.

1.3 Initial Scantling Requirements (1995)

The initial thickness of plating, the section modulus of longitudinals/stiffeners, and the scantlings of the
main supporting structures are to be determined in accordance with Section 5C-1-4 for the “net” ship.
These “net” ship values are to be used for further assessment as required in the following paragraph. The
relevant nominal design corrosion values are then added to obtain the full scantling requirements.

1.5 Strength Assessment – Failure Modes (1995)

A total assessment of the structures, determined on the basis of the initial strength criteria in Section 5C-1-
4 is to be carried out against the following three failure modes.
1.5.1 Material Yielding
The calculated stress intensities are not to be greater than the yielding state limit given in 5C-1-5/3.1
for all load cases specified in 5C-1-3/9.
1.5.2 Buckling and Ultimate Strength
For each individual member, plate or stiffened panel, the buckling and ultimate strength is to be in
compliance with the requirements specified in 5C-1-5/5. In addition, the hull girder ultimate strength
is to be in accordance with 5C-1-5/5.11.
1.5.3 Fatigue
The fatigue strength of structural details and welded joints in highly stressed regions is to be
analyzed in accordance with 5C-1-5/7.

1.7 Structural Redundancy and Residual Strength (1995)

Consideration should be given to structural redundancy and hull girder residual strength in the early design
stages.
In addition to other requirements of these Rules, vessels which have been built in accordance with the
procedure and criteria for calculating and evaluating the residual strength of hull structures, as outlined in
the ABS Guide for Assessing Hull Girder Residual Strength, will be classed and distinguished in the
Record by the symbol RES placed after the appropriate hull classification notation.

20 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 2 Design Considerations and General Requirements 5C-1-2

3 Nominal Design Corrosion Values (NDCV) (1995)

3.1 General
As indicated in 5C-1-2/1.1, the strength criteria specified in this Chapter are based on a “net” ship approach,
wherein the nominal design corrosion values are deducted.
The “net” thickness or scantlings correspond to the minimum strength requirements acceptable for
classification, regardless of the design service life of the vessel. In addition to the coating protection
specified in the Rules for all ballast tanks, minimum corrosion values for plating and structural members as
given in 5C-1-2/Table 1 and 5C-1-2/Figure 1 are to be applied. These minimum values are being
introduced solely for the above purpose, and are not to be construed as renewal standards.
In view of the anticipated higher corrosion rates for structural members in some regions, such as highly
stressed areas, additional design margins should be considered for the primary and critical structural
members to minimize repairs and maintenance costs. The beneficial effects of these design margins on
reduction of stresses and increase of the effective hull girder section modulus can be appropriately
accounted for in the design evaluation.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 21

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 2 Design Considerations and General Requirements 5C-1-2

FIGURE 1
Nominal Design Corrosion Values (NDCV) (1995)
E
FLANG
WEB &
2.0mm 2.0mm
SPLASH ZONE
1.5m BELOW TANK

1.0mm
1.5mm
2.0mm WEB GE 1.5mm
FLAN
WE
FLANB 1.5mm
TOP

GE 1.5
mm
1.0mm

m
1.5m m
WEB E 1.5m
A NG
F L
WEB WEB
2.0mm FLAN 1.0mm
GE 1
m .0mm
2.0m
FLANGE
1.0mm

1.5m
m 1.5mm WEB
FLAN 1.5mm
GE 1
.0mm
WEB
1.0m FLAN 1.0mm
m GE 1
.0mm

m
1.5m
m
1 .5 m

m
1.5m
m
1.0m

2.0m
m m
2 .0 m

m
1.0m

WE
B2
FLA .0m
NG m
E2
.0m
m

22 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 2 Design Considerations and General Requirements 5C-1-2

TABLE 1
Nominal Design Corrosion Values (NDCV) (1995)
Nominal Design Corrosion Values
in mm (in.)
Ballast Tank
Structural Element/Location Cargo Tank Effectively Coated
Deck Plating 1.0 (0.04) 2.0 (0.08)
Side Shell Plating NA 1.5 (0.06)
Bottom Plating NA 1.0 (0.04)
Inner Bottom Plating 1.5 (0.06)
Longitudinal Bulkhead Plating Between cargo tanks 1.0 (0.04) N.A.
Other Plating 1.5 (0.06)
Transverse Bulkhead Plating Between cargo tanks 1.0 (0.04) N.A.
Other Plating 1.5 (0.06)
Transverse & Longitudinal Deck Supporting Members 1.5 (0.06) 2.0 (0.08)
Double Bottom Tanks Internals (Stiffeners, Floors and Girders) N.A. 2.0 (0.08)
Vertical Stiffeners and Supporting Members Elsewhere 1.0 (0.04) 1.0 (0.04)
Non-vertical Longitudinals/Stiffeners and Supporting Members Elsewhere 1.5 (0.06) 2.0 (0.08)
Notes
1 It is recognized that corrosion depends on many factors including coating properties, cargo composition, inert gas
properties and temperature of carriage, and that actual wastage rates observed may be appreciably different from
those given here.
2 Pitting and grooving are regarded as localized phenomena and are not covered in this table.
3 For nominal design corrosion values for single hull and mid-deck type tankers, see Appendix 5C-1-A3 and
Appendix 5C-1-A4.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 23

PART Section 3: Load Criteria

5C
CHAPTER 1 Vessels Intended to Carry Oil in Bulk (150 meters
(492 feet) or more in Length)

SECTION 3 Load Criteria

1 General

1.1 Load Components (1995)

In the design of the hull structure of tankers, all load components with respect to the hull girder and local
structure as specified in this Chapter and Section 3-2-1 are to be taken into account. These include static
loads in still water, wave-induced motions and loads, sloshing, slamming, dynamic, thermal and ice loads,
where applicable.

3 Static Loads (1995)

3.1 Still-water Bending Moment

For still-water bending moment calculations, see 3-2-1/3.3.
When a direct calculation of wave-induced loads [i.e., longitudinal bending moments and shear forces,
hydrodynamic pressures (external) and inertial forces and added pressure heads (internal)] is not submitted,
envelope curves of the still-water bending moments (hogging and sagging) and shear forces (positive and
negative) are to be provided.
Except for special loading cases, the loading patterns shown in 5C-1-3/Figure 1 are to be considered in
determining local static loads.

24 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

FIGURE 1
Loading Pattern (1 July 2005)

a. Load Cases No. 1 and 3 b. Load Cases No. 2 and 4

2/3 Design Draft 0.9 Design Draft

c. Load Case No. 5 g. Load Case No. 9 * d. Load Case No. 6 h. Load Case No. 10 *
2/3 Design Draft 1/4 Design Draft 2/3 Design Draft 1/4 Design Draft

e. Load Case No. 7 f. Load Case No. 8

2/3 Design Draft Design Draft

For detailed loading information see 5C-1-3/Table 1A and 5C-1-3/Table 1B.

* For L.C. 9 and 10, where static conditions, such as tank testing, that have the same load pattern as the center row of tanks
resulting in a draft less than 1/4 Design Draft, the actual static condition draft is to be used. For vessels with two outer
longitudinal bulkheads only (inner skin), the minimum actual static condition or tank test draft is to be used. The value of
ks = 1.0 is to be used in all tanks. The tanks are to be loaded considering the actual height of the overflow pipe, which is not
to be taken less than 2.44 m (8 feet) above the deck at side.
(1 July 2005) For a hull structure with the main supporting members that are asymmetric forward and after the mid-tank
transverse bulkheads, the above load cases are to be evaluated by turning the finite element model by 180 degrees with
respect to the vertical axis.
(1 July 2005) For a hull structure that is asymmetric with respect to the centerline plane, the additional load cases mirroring
the above asymmetric load case are to be evaluated.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 25

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

5 Wave-induced Loads (1995)

5.1 General
Where a direct calculation of the wave-induced loads is not available, the approximation equations given
below and specified in 3-2-1/3.5 may be used to calculate the design loads.
When a direct calculation of the wave-induced loads is performed, envelope curves of the combined wave
and still-water bending moments and shear forces, covering all the anticipated loading conditions, are to be
submitted for review.

5.3 Horizontal Wave Bending Moment and Shear Force (1995)

5.3.1 Horizontal Wave Bending Moment
The horizontal wave bending moment, positive (tension port) or negative (tension starboard), may
be obtained from the following equation:
MH = ± mhK3C1L2DCb × 10-3 kN-m (tf-m, Ltf-ft)
where
mh = distribution factor, as given by 5C-1-3/Figure 2
K3 = 180 (18.34, 1.68)
D = depth of vessel, as defined in 3-1-1/7, in m (ft)
C1, L, and Cb are as given in 3-2-1/3.5.

5.3.2 Horizontal Wave Shear Force

The envelope of horizontal wave shearing force, FH, positive (toward port forward) or negative
(toward starboard aft), may be obtained from the following equation:
FH = ± fh kC1LD(Cb + 0.7) × 10-2 kN (tf, Ltf)
where
fh = distribution factor, as given in 5C-1-3/Figure 3
k = 36 (3.67, 0.34)
C1, L, D and Cb are as defined in 5C-1-3/5.3.1 above.

5.5 External Pressures

5.5.1 Pressure Distribution
The external pressures, pe , (positive toward inboard), imposed on the hull in seaways can be
expressed by the following equation at a given location:
pe = ρ g(hs + ku hde) ≥ 0 N/cm2 (kgf/cm2, lbf/in2)
where
ρg = specific weight of sea water
= 1.005 N/cm2-m (0.1025 kgf/cm2-m, 0.4444 lbf/in2-ft)
hs = hydrostatic pressure head in still water, in m (ft)
ku = load factor, and may be taken as unity unless otherwise specified.
hde = hydrodynamic pressure head induced by the wave, in m (ft), may be
calculated as follows:
= kc hdi

26 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

where
kc = correlation factor for a specific combined load case, as given in 5C-1-3/7.1
and 5C-1-3/9
hdi = hydrodynamic pressure head, in m (ft), at location i (i =1, 2, 3, 4 or 5; see
5C-1-3/Figure 4)
= klαi hdo in m (ft)
kl = distribution factor along the length of the vessel
= 1 + (klo − 1) cos μ, klo is as given in 5C-1-3/Figure 5
= 1.0 amidships
hdo = 1.36 kC1 in m (ft)
C1 = as defined in 3-2-1/3.5
k = 1 (1, 3.281)
αi = distribution factor around the girth of vessel at location i.

= 1.00 − 0.25 cos μ for i = 1, at WL, starboard

= 0.40 − 0.10 cos μ for i = 2, at bilge, starboard
= 0.30 − 0.20 sin μ for i = 3, at bottom centerline
= 2α3 − α2 for i = 4, at bilge, port

= 0.75 − 1.25 sin μ for i = 5, at WL, port

αi at intermediate locations of i may be obtained by linear interpolation.
μ = wave heading angle, to be taken from 0° to 90° (0° for head sea, 90° for
beam sea for wave coming from starboard)
The distribution of the total external pressure including static and hydrodynamic pressure is illustrated
in 5C-1-3/Figure 6.
5.5.2 Extreme Pressures
In determining the required scantlings of local structural members, the extreme external pressure,
pe , to be used, is as defined in 5C-1-3/5.5.1 with ku as given in 5C-1-3/7 and 5C-1-3/9.

5.5.3 Simultaneous Pressures

When performing 3D structural analysis, the simultaneous pressure along any portion of the hull
girder may be obtained from:
pes = ρ g(hs + kf ku hde) ≥ 0 N/cm2 (kgf/cm2, lbf/in2)
where
kf is a factor denoting the phase relationship between the reference station and adjacent stations
considered along the vessel’s length, and may be determined as follows:
2π ( x − x o )
kf = kfo { 1 − [ 1 − cos ] cos μ }
L
where
x = distance from A.P. to the station considered, in m (ft)
xo = distance from A.P. to the reference station*, in m (ft).
L = the vessel length, as defined in 3-1-1/3, in m (ft)

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 27

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

μ = the wave heading angle, to be taken from 0° to 90°

kfo = ±1.0, as specified in 5C-1-3/Table 1.
* The reference station is the point along the vessel’s length where the wave trough or
crest is located and may be taken as the mid-point of the mid-hold of the three hold
model.
The simultaneous pressure distribution around the girth of the vessel is to be determined based on
the wave heading angles specified in 5C-1-3/7 and 5C-1-3/9.

5.7 Internal Pressures – Inertia Forces and Added Pressure Heads (1995)
5.7.1 Ship Motions and Accelerations
To determine the inertial forces and added pressure heads for a completely filled cargo or ballast
tank, the dominating ship motions, pitch and roll, and the resultant accelerations induced by the wave
are required. When a direct calculation is not available, the equations given below may be used.
5.7.1(a) Pitch (1 July 2005). The pitch amplitude: (positive bow up)
φ = k1(V/Cb)1/4/L, in deg., but need not to be taken more than 10 deg.
The pitch natural period:

Tp = k2 C b d i seconds.

where
k1 = 1030 (3378) for L in m (ft)
k2 = 3.5 (1.932) for di in m (ft)
V = 75% of the design speed Vd, in knots for the purpose of calculating pitch and
roll amplitudes for both strength and fatigue strength formulation. V is not to
be taken less than 10 knots. Vd is defined in 3-2-14/3.
di = draft amidships for the relevant loading conditions.
L and Cb are defined in 3-1-1/3.1 and 3-1-1/11.3, respectively.
5.7.1(b) Roll (1 July 2005). The roll amplitude: (positive starboard down)
θ = CR (35 − kθ Cdi Δ/1000) if Tr > 20 seconds.

θ = CR (35 − kθ Cdi Δ/1000) (1.5375 − 0.027Tr) if 12.5 ≤ Tr ≤ 20 seconds

θ = CR (35 − kθ Cdi Δ/1000) (0.8625 + 0.027Tr) if Tr ≤ 12.5 seconds

where
θ is in degrees, but need not to be taken greater than 30°.
kθ = 0.005 (0.05, 0.051)
CR = 1.3 − 0.025V

Cdi = 1.06 (di/df) − 0.06

di = draft amidships for the relevant loading conditions, m (ft)
df = draft, as defined in 3-1-1/9, m (ft)

Δ = kd LBdf Cb kN (tf, Ltf)

kd = 10.05 (1.025, 0.0286)
L and B are as defined in Section 3-1-1.

28 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

The roll natural motion period:

Tr = k4 kr /GM1/2 seconds
where
k4 = 2 (1.104) for kr, GM in m (ft)
kr = roll radius of gyration, in m (ft), and may be taken as 0.35B for full load
conditions and 0.45B for ballast conditions.
GM = metacentric height, to be taken as:
= GM (full) for full draft
= 1.1 GM (full) for 9/10 df
= 1.5 GM (full) for 2/3 df
= 2.0 GM (full) for 1/2 df
GM (full) = metacentric height for fully loaded condition
If GM (full) is not available, GM (full) may be taken as 0.12B for the
purpose of estimation.
5.7.1(c) Accelerations (1 July 2005). The vertical, longitudinal and transverse accelerations of
tank contents (cargo or ballast), av, al and at may be obtained from the following formulae:

av = Cv kv ao g m/sec2 (ft/sec2) positive downward

al = Cl kl ao g m/sec2 (ft/sec2) positive forward

at = Ct kt ao g m/sec2 (ft/sec2) positive starboard

where
ao = ko (2.4/L1/2 + 34/L − 600/L2) for L in m

= ko (4.347/L1/2 + 111.55/L − 6458/L2) for L in ft

ko = 1.3 – 0.47Cb for strength formulation and assessment of local structural
elements and members in Section 5C-1-4, 5C-1-5/1, 5C-1-3/3 and 5C-1-5/5.
= 0.86 + 0.048V − 0.47Cb for fatigue strength formulation in 5C-1-5/7 and
Appendix 5C-1-A1
Cv = cos μ + (1 + 2.4 z/B) (sin μ)/kv

μ = wave heading angle in degrees, 0° for head sea, and 90° for beam sea for
wave coming from starboard
kv = [1 + 0.65(5.3 − 45/L)2 (x/L − 0.45)2]1/2 for L in m

= [1 + 0.65(5.3 − 147.6/L)2 (x/L − 0.45)2]1/2 for L in ft

Cl = 0.35 − 0.0005(L − 200) for L in m

= 0.35 − 0.00015 (L − 656) for L in ft

kl = 0.5 + 8y/L
Ct = 1.27[1 + 1.52(x/L − 0.45)2]1/2
kt = 0.35 + y/B
L and B are the length and breadth of the vessel respectively, as defined in Section 3-1-1, in m (ft).

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 29

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

x = longitudinal distance from the A.P. to the station considered, in m (ft)

y = vertical distance from the waterline to the point considered, in m (ft),
positive upward
z = transverse distance from the centerline to the point considered, in m (ft),
positive starboard
g = acceleration of gravity = 9.8 m/sec2 (32.2 ft/sec2)
5.7.2 Internal Pressures
5.7.2(a) Distribution of Internal Pressures. (1 July 2000) The internal pressure, Pi (positive
toward tank boundaries), for a completely filled tank may be obtained from the following formula:
pi = ksρ g(η + ku hd) + po ≥ 0 in N/cm2 (kgf/cm2, lbf/in2)

po = (pvp − pn) ≥ 0 in N/cm2 (kgf/cm2, lbf/in2)

where
pvp = pressure setting on pressure/vacuum relief valve ≤ 6.90 N/cm2 (0.71 kgf/cm2,
10.00 lbf/in2) for integral-gravity tanks
pn = 2.06 N/cm2 (0.21 kgf/cm2, 3.00 lbf/in2)

ρg = specific weight of the liquid, not to be taken less than 1.005 N/cm2-m
(0.1025 kgf/cm2-m, 0.4444 lbf/in2-ft)
η = local coordinate in vertical direction for tank boundaries measuring from the
top of the tanks, as shown 5C-1-3/Figure 7, in m (ft)
For lower ballast tanks, a distance equivalent to 2/3 of the distance from the top of the tank to the
top of the overflow [minimum 760 mm (30 in.) above deck] is to be added to η.
ks = load factor – see also 5C-1-3/5.7.2(c)
= 1.0 for structural members 1 through 10 in 5C-1-3/Table 3, and for all loads
from ballast tanks
= 0.878 for ρ g of 1.005 N/cm2-m (0.1025 kgf/cm2-m, 0.4444 lbf/in2-ft) and
1.0 for ρ g of 1.118 N/cm2-m (0.114 kgf/cm2-m, 0.4942 lbf/in2-ft) and above
for structural members 11 through 17 in 5C-1-3/Table 3
For cargo ρ g between 1.005 N/cm2-m (0.1025 kgf/cm2-m, 0.4444 lbf/in2-ft)
and 1.118 N/cm2-m (0.114 kgf/cm2-m, 0.4942 lbf/in2-ft), the factor ks may be
determined by interpolation
ku = load factor and may be taken as unity unless otherwise specified
hd = wave-induced internal pressure head, including inertial force and added
pressure head.
= kc(η ai /g + Δhi ) in m (ft)
kc = correlation factor and may be taken as unity unless otherwise specified
ai = effective resultant acceleration, in m/sec2 (ft/sec2), at the point considered
and may be approximated by
= 0.71Cdp[wv av + wl(l/h)al + wt(b/h)at]
Cdp is as specified in 5C-1-3/5.7.2(d).
av, al and at are as given in 5C-1-3/5.7.1(c).
wv, wl and wt are weighted coefficients, showing directions, as specified in 5C-1-3/Table 1 and
5C-1-3/Table 3.

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

Δhi = added pressure head due to pitch and roll motions at the point considered, in
m (ft), may be calculated as follows
i) for bow down and starboard down (φe < 0, θe > 0)

Δhi = ξ sin(–φe) + Cru (ζe sin θe cos φe + ηe cos θe cos φe − η)

ζe = b−ζ

ηe = η
ii) for bow up and starboard up (φe > 0, θe < 0)

Δhi = (l − ξ) sin φe + Cru (ζe sin(–θe) cos φe + ηe cos θe cos φe − η)

ζe = ζ − δb
ηe = η − δh
ξ, ζ, η are the local coordinates, in m (ft), for the point considered with respect to the origin in
5C-1-3/Figure 7.
Cru is as specified in 5C-1-3/5.7.2(d).
δb and δh are local coordinates adjustments, in m (ft), for the point considered with respect to the
origin shown in 5C-1-3/Figure 7.
where
θe = 0.71 Cθ θ

φe = 0.71 Cφ φ

l = length of the tank, in m (ft)

h = depth of the tank, in m (ft)
b = breadth of the tank considered, in m (ft)
φ and θ are pitch and roll amplitudes, as given in 5C-1-3/5.7.1(a) and 5C-1-3/5.7.1(b)
Cφ and Cθ are weighted coefficients, showing directions as given in 5C-1-3/Table 1 and 5C-1-3/Table 3
Where pressure-vacuum valves of cargo tanks are set at greater than 2.06 N/cm2 (0.21 kgf/cm2,
3 lbf/in2), the value of Pi is to be increased appropriately.
5.7.2(b) Extreme Internal Pressure. For assessing local structures at a tank boundary, the extreme
internal pressure with ku, as specified in 5C-1-3/7, is to be considered.
5.7.2(c) Simultaneous Internal Pressures (1 July 2000). In performing a 3D structural analysis,
the internal pressures may be calculated in accordance with 5C-1-3/5.7.2(a) and 5C-1-3/5.7.2(b)
above for tanks in the mid-body. For tanks in the fore or aft body, the pressures should be
determined based on linear distributions of accelerations and ship motions along the length of the
vessel.
Note: In performing a 3D structural analysis, ks in 5C-1-3/5.7.2(a) is to be taken as:
ks = 1.0 for all loads from ballast tanks
= 0.878 for ρ g of 1.005 N/cm2-m (0.1025 kgf/cm2-m, 0.4444 lbf/in2-ft) and
1.0 for ρ g of 1.118 N/cm2-m (0.114 kgf/cm2-m, 0.4942 lbf/in2-ft) and above
for all loads from cargo tanks
For cargo ρ g between 1.005 N/cm2-m (0.1025 kgf/cm2-m, 0.4444 lbf/in2-ft)
and 1.118 N/cm2-m (0.114 kgf/cm2-m, 0.4942 lbf/in2-ft), the factor ks may be
determined by interpolation

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 31

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

5.7.2(d) Definition of Tank Shape and Associated Coefficients

i) J-shaped Tank
A tank having the following configurations is considered as a “J-shaped” tank.
b/b1 ≥ 5.0 and h/h1 ≥ 5.0
where
b = extreme breadth at the tank top of the tank considered
b1 = least breadth of wing tank part of the tank considered
h = extreme height of the tank considered
h1 = least height of double bottom part of the tank considered
as shown in 5C-1-3/Figure 7.
The coefficients Cdp and Cru are as follows:
Cdp = 0.7
Cru = 1.0
ii) Rectangular Tank
The following tank is considered as a rectangular tank:
b/b1 ≤ 3.0 or h/h1 ≤ 3.0
The coefficients Cdp and Cru of the tank are as follows:
Cdp = 1.0
Cru = 1.0
iii) U-shaped Tank
A half of a “U-shaped” tank, divided at the centerline, should satisfy the condition of a “J-shaped” tank.
The coefficients Cdp and Cru are as follows:
Cdp = 0.5
Cru = 0.7
iv) In a case where the minimum tank ratio of b/b1 or h/h1 whichever is lesser, is greater than
3.0 but less than 5.0, the coefficients Cdp and Cru of the tank are to be determined by the
following interpolation:
J-shaped Tank in head and non-head seas, U-shaped Tank in head seas:
Cdp = 1.0 − 0.3 (the min. tank ratio - 3.0) / 2.0
U-shaped Tank in non-head seas:
Cdp = 1.0 − 0.5 (the min. tank ratio - 3.0) / 2.0
U-shaped Tank:
Cru = 1.0 − 0.3 (the min. tank ratio - 3.0) / 2.0
v) For non-prismatic tanks mentioned above, b1, h and h1 are to be determined based on the
extreme section.

32 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

FIGURE 2
Distribution Factor mh (1995)

1.0
Distribution m h

0.0
0.0 0.4 0.6 1.0
Aft Forward
end of L end of L
Distance from the aft end of L in terms of L

FIGURE 3
Distribution Factor fh (1995)

1.0
fh

0.7
Distribution

0.0
0.0 0.2 0.3 0.4 0.60 0.7 0.8 1.0
Aft Forward
end of L end of L
Distance from the aft end of L in terms of L

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 33

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

FIGURE 4
Distribution of hdi (1995)
h = freeboard to W.L.
Freeboard Deck

hd5 hd1 W.L.

h or h*
whichever is lesser

h hd2
hd4 d3
View from the Stern

Note: h* = ku kc hd1 for nominal pressure

h* = kf ku hd1 for simultaneous pressure

FIGURE 5
Pressure Distribution Function klo (1995)

2.5
Distribution klo

1.5

1.0

0.0
0.0 0.2 0.7 1.0
Aft Forward
end of L end of L
Distance from the aft end of L in terms of L

34 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

FIGURE 6
Illustration of Determining Total External Pressure (1997)

h
hd1

h or h*
whichever is lesser

hd : Hydrodynamic Pressure Head (indicates negative)

hs : Hydrostatic Pressure Head in Still Water

: Total External Pressure Head

Note: h* = ku kc hd1 for nominal pressure

h* = kf ku hd1 for simultaneous pressure

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 35

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

FIGURE 7
Definition of Tank Geometry (1995)

ξ
F.P.

b1

h l

h1

Tank Shape Parameters ζ O

b

B/2
L
C
Plan View
δb ξ

δb δh
l δh
O
ζ

ζ O

b
η
B/2 Elevation
L
C

η
Isometric View

For lower ballast tanks, η is to be measured from a point located at 2/3 the distance from the top of the tank
to the top of the overflow (minimum 760 mm above deck).

36 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

FIGURE 8
Location of Tank for Nominal Pressure Calculation (1997)

Tanks Considered

5 4 3 2 1

AP
FP

0.4L

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 37

 Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

TABLE 1A
Combined Load Cases for Yielding and Buckling Strength Formulation (1)
(1 July 2005)
L.C. 1 L.C. 2 L.C. 3 (3) L.C. 4 (3) L.C. 5 L.C. 6 L.C. 7 L.C. 8 L.C. 9 L.C. 10
A. Hull Girder Loads (See 5C-1-3/5)
Vertical B.M. Sag (–) Hog (+) Sag (–) Hog (+) Sag (–) Hog (+) Sag (–) Hog (+) — —
kc 1.0 1.0 0.7 0.7 0.3 0.3 0.4 0.4 0.0 0.0
Vertical S.F. (2) (+) (–) (+) (–) (+) (–) (+) (–) — —
kc 0.5 0.5 1.0 1.0 0.3 0.3 0.4 0.4 0.0 0.0
Horizontal B.M. (–) (+) (–) (+)
kc 0.0 0.0 0.0 0.0 0.3 0.3 1.0 1.0 0.0 0.0
Horizontal S.F. (+) (–) (+) (–)
kc 0.0 0.0 0.0 0.0 0.3 0.3 0.5 0.5 0.0 0.0
B. External Pressure (See 5C-1-3/5.5)
kc 0.5 0.5 0.5 1.0 0.5 1.0 0.5 1.0 0.0 0.0
kf0 -1.0 1.0 -1.0 1.0 -1.0 1.0 -1.0 1.0 0.0 0.0
C. Internal Tank Pressure (See 5C-1-3/5.7)
kc 0.4 0.4 1.0 0.5 1.0 0.5 1.0 0.5 0.0 0.0
wv 0.75 -0.75 0.75 -0.75 0.25 -0.25 0.4 -0.4 0.0 0.0
wl Fwd Bhd Fwd Bhd Fwd Bhd Fwd Bhd — — Fwd Bhd Fwd Bhd — —
0.25 -0.25 0.25 -0.25 0.2 -0.2
Aft Bhd Aft Bhd Aft Bhd Aft Bhd — — Aft Bhd Aft Bhd — —
-0.25 0.25 -0.25 0.25 -0.2 0.2
wt — — — — Port Bhd Port Bhd Port Bhd Port Bhd — —
-0.75 0.75 -0.4 0.4
— — — — Stbd Bhd Stbd Bhd Stbd Bhd Stbd Bhd — —
0.75 -0.75 0.4 -0.4
cφ, Pitch -0.35 0.35 -0.7 0.7 0.0 0.0 -0.3 0.3 0.0 0.0
cθ, Roll 0.0 0.0 0.0 0.0 1.0 -1.0 0.3 -0.3 0.0 0.0
D. Reference Wave Heading and Motion of Vessel
Heading Angle 0 0 0 0 90 90 60 60 — —
Heave Down Up Down Up Down Up Down Up — —
Pitch Bow Bow Up Bow Bow Up — — Bow Bow Up — —
Down Down Down
Roll — — — — Stbd Stbd Up Stbd Stbd Up — —
Down Down
Notes:
1 ku = 1.0 for all load components.
2 (1 July 2005) The sign convention for the shear force corresponds to the forward end of the middle hold.
3 (1 July 2005) Load cases 3 & 4 are to be analyzed for the structural model that is fully balanced under the
boundary forces to achieve the specified hull girder vertical bending moment at the middle of the model. These
load cases are also to be analyzed for the structural model that is fully balanced under the boundary forces to
achieve the specified hull girder vertical shear force s at the mid-tank transverse bulkheads.

38 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

 Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

TABLE 1B
Combined Load Cases for Fatigue Strength Formulation (1) (1 July 2005)
L.C. 1 L.C. 2 L.C. 3 L.C. 4 L.C. 5 L.C. 6 L.C. 7 L.C. 8 L.C. 9 L.C. 10
A. Hull Girder Loads (See 5C-1-3/5)
Vertical B.M. Sag (–) Hog (+) Sag (–) Hog (+) Sag (–) Hog (+) Sag (–) Hog (+) — —
kc 1.0 1.0 0.7 0.7 0.3 0.3 0.4 0.4 0.0 0.0
Vertical S.F. (2) (+) (–) (+) (–) (+) (–) (+) (–) — —
kc 0.5 0.5 1.0 1.0 0.3 0.3 0.4 0.4 0.0 0.0
Horizontal B.M. (–) (+) (–) (+)
kc 0.0 0.0 0.0 0.0 0.3 0.3 1.0 1.0 0.0 0.0
Horizontal S.F. (+) (–) (+) (–)
kc 0.0 0.0 0.0 0.0 0.3 0.3 0.5 0.5 0.0 0.0
B. External Pressure (See 5C-1-3/5.5)
kc 0.5 0.5 0.5 1.0 0.5 1.0 0.5 1.0 0.0 0.0
kf0 -1.0 1.0 -1.0 1.0 -1.0 1.0 -1.0 1.0 0.0 0.0
C. Internal Tank Pressure (See 5C-1-3/5.7)
kc 0.4 0.4 1.0 0.5 1.0 0.5 1.0 0.5 0.0 0.0
wv 0.75 -0.75 0.75 -0.75 0.25 -0.25 0.4 -0.4 0.0 0.0
wl Fwd Bhd Fwd Bhd Fwd Bhd Fwd Bhd — — Fwd Bhd Fwd Bhd — —
0.25 -0.25 0.25 -0.25 0.2 -0.2
Aft Bhd Aft Bhd Aft Bhd Aft Bhd — — Aft Bhd Aft Bhd — —
-0.25 0.25 -0.25 0.25 -0.2 0.2
wt — — — — Port Bhd Port Bhd Port Bhd Port Bhd — —
-0.75 0.75 -0.4 0.4
— — — — Stbd Bhd Stbd Bhd Stbd Bhd Stbd Bhd — —
0.75 -0.75 0.4 -0.4
cφ, Pitch -1.0 1.0 -1.0 1.0 0.0 0.0 -0.7 0.7 0.0 0.0
cθ, Roll 0.0 0.0 0.0 0.0 1.0 -1.0 0.7 -0.7 0.0 0.0
D. Reference Wave Heading and Motion of Vessel
Heading Angle 0 0 0 0 90 90 60 60 — —
Heave Down Up Down Up Down Up Down Up — —
Pitch Bow Bow Up Bow Bow Up — — Bow Bow Up — —
Down Down Down
Roll — — — — Stbd Stbd Up Stbd Stbd Up — —
Down Down
Notes:
1 ku = 1.0 for all load components.
2 The sign convention for the shear force corresponds to the forward end of the middle hold.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 39

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

TABLE 2
Load Cases for Sloshing (1 July 2005)
Type A: For Horizontal Girder on the Aft Side of Transverse Bulkhead
Sloshing
Hull girder Loads (1) External Pressures Pressures (2) Reference Wave Heading and Motions
V.B.M. V.S.F. ku, kc Heading
[H.B.M. H.S.F. ku, kc ] ku kc kfo ku kc Angle Heave Pitch Roll
LC S - 1 (–) (+) 1.0 0.4 1.0 0.5 -1.0 1.0 1.0 60° Down Bow Stbd
Down Down
[(–) (+) 1.0 0.7] -0.9 0.9
LC S - 2 (+) (–) 1.0 0.4 1.0 1.0 1.0 1.0 1.0 60° Up Bow Up Stbd Up
[(+) (–) 1.0 0.7] 0.9 -0.9

Type B: For Horizontal Girder on the Forward Side of Transverse Bulkhead

Sloshing
Hull girder Loads (1) External Pressures Pressures (2) Reference Wave Heading and Motions
V.B.M. V.S.F. ku, kc Heading
[H.B.M. H.S.F. ku, kc ] ku kc kfo ku kc Angle Heave Pitch Roll
LC S - 1 (–) (+) 1.0 0.4 1.0 0.5 1.0 1.0 1.0 60° Up Bow Up Stbd Up
[(–) (+) 1.0 0.7] 0.9 -0.9
LC S - 2 (+) (–) 1.0 0.4 1.0 1.0 -1.0 1.0 1.0 60° Down Bow Stbd
Down Down
[(+) (–) 1.0 0.7] -0.9 0.9
Notes:
1 For determining the total vertical bending moment for the above two load cases, 70% of the maximum designed
still water bending moment may be used at the specified wave vertical bending moment station.
where:
V.B.M. is vertical wave bending moment
V.S.F. is vertical wave shear force
H.B.M. is horizontal wave bending moment
H.S.F. is horizontal wave shear force
2 The vertical distribution of the sloshing pressure Pis is shown in 5C-1-3/Figure 9.

40 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

TABLE 3
Design Pressure for Local and Supporting Members
A. Plating & Longitudinals/Stiffeners. (1997)
The nominal pressure, p = |pi − pe|, is to be determined from load cases
“a” & “b” below, whichever is greater, with ku = 1.10 and kc = 1.0 unless otherwise specified in the table
Case “a” – At fwd end of the tank Case “b” – At mid tank/fwd end of tank
Coefficients Draft/Wave Coefficients
Structural Members/ Draft/Wave Location and Heading Location and
Components Heading Angle Loading Pattern pi pe Angle Loading Pattern pi pe

1. Bottom Plating 2/3 design Full ballast tank Ai Ae design Midtank of — Be

& Long’l draft/0° draft/0° empty ballast
tanks
2. Inner Bottom 2/3 design Full ballast tank, Ai — design Fwd end of full Ai —
Plating & draft/0° cargo tanks empty draft/0° cargo tank,
Long’l ballast tanks
empty
3. Side Shell 2/3 design Starboard side of Bi Ae design Midtank of — Be
Plating & draft/60° full ballast tank draft/60° empty ballast
Long’l tanks
4. * Deck Plating & design draft/0° Full cargo tank Di —
Long’l (Cargo
Tank)
5. Deck Plating & 2/3 design Full ballast tank Di —
Long’l (Ballast draft/0°
Tank)
6. * Inner Skin design draft/ Starboard side of Bi — 2/3 design Fwd. end and Bi —
Long’l Bhd. 60° full cargo tank, draft/60° starboard side of
Plating & ballast tank empty full ballast tank,
Long’l cargo tank
empty
7. * Centerline design draft/ Full starboard Ei —
Long’l Bhd. 60° cargo and ballast
Plating & tanks, adjacent
Long’l tank empty
8. * Other Long’l design draft/ Starboard side of Bi — design Fwd. end and Bi —
Bhd. Plating & 60° full inward cargo draft/60° starboard side of
Long’l tanks, adjacent (1997) full outboard
tank empty cargo tanks,
adjacent tank
empty
9. * Trans. Bhd. design draft/0° Fwd. bhd. of full Ai —
Plating & cargo tank,
Stiffener adjacent tanks
(Cargo Tank) empty
10. * Trans. Bhd. 2/3 design Fwd. bhd. of full Ai —
Plating & draft/0° ballast tank,
Stiffener adjacent tanks
(Ballast Tank) empty
* See note 4

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 41

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

TABLE 3 (continued)
Design Pressure for Local and Supporting Members
B. Main Supporting Members
The nominal pressure, p = |pi − pe|, is to be determined at the mid-span of the structural member at starboard side of vessel from
load cases “a” & “b” below, whichever is greater, with ku = 1.0 and kc = 1.0 unless otherwise specified in the table
Case “a” – Mid-tank for Transverses Case “b” – Mid-tank for Transverses
Coefficients Draft/Wave Coefficients
Structural Members/ Draft/Wave Location and pi pe Heading Location and pi pe
Components Heading Angle Loading Pattern Angle Loading Pattern
11. Double Bottom 2/3 design Full cargo tank, Ai Ae design Mid-tank, cargo — Be
Floor & Girder draft/0° ballast tanks empty draft/0° and ballast tanks
empty
12. Side Transverse 2/3 design Wing cargo tanks Bi — design Center cargo — Be
draft/60° full draft/60° tank full, wing
cargo tanks
empty
13. Transverse on
Long’l. Bhd.:
Tanker with C.L. 2/3 design Starboard cargo Fi —
Long’l, Bhd., draft/60° tank full, port-
without cross empty
ties, (5C-1-4/
Figure 2A-b,
5C-1-4/Figure
2A-c):
Tanker with four
Long’l. Bhds.
with cross ties:
Cross Ties in 2/3 design Center cargo tank Ci — 2/3 design Center cargo Gi —
wing cargo draft/90° full, wing cargo draft/90° tank empty,
tanks (5C-1-4/ tanks empty wing cargo
Figure 2A-d) tanks full
Cross Tie in 2/3 design Wing cargo tanks Fi — 2/3 design Center cargo Bi —
center cargo draft/60° full, center cargo draft/60° tank full, wing
tank, (5C-1-4/ tank empty cargo tanks
Figure 2A-e) empty
Tanker with four 2/3 design Wing cargo tanks Fi — 2/3 design Center cargo Ci —
Long’l. Bhds. draft/60° full, center cargo draft/60° tank full, wing
without cross tank empty cargo tanks
ties, (5C-1-4/ empty
Figure 2A-f)
14. Horizontal 2/3 design Fwd Bhd. of full Bi —
Girder and draft/60° cargo tank,
Vertical Web on adjacent tanks
Transverse empty
Bulkhead
15. Cross Ties: 2/3 design Center cargo tank Ci — design Wing cargo — Be
Cross Ties in draft/90° full, wing cargo draft/60° tanks empty,
wing cargo tanks tanks empty center cargo
(5C-1-4/Figure tank full
2A-d) (starboard)
Cross tie in 2/3 design Wing cargo tanks Fi —
center cargo tank draft/60° full, center cargo
(5C-1-4/Figure tank empty
2A-e)

42 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

TABLE 3 (continued)
Design Pressure for Local and Supporting Members
B. Main Supporting Members
The nominal pressure, p = |pi − pe|, is to be determined at the mid-span of the structural member at starboard side of vessel from
load cases “a” & “b” below, whichever is greater, with ku = 1.0 and kc = 1.0 unless otherwise specified in the table
Case “a” – Mid-tank for Transverses Case “b” – Mid-tank for Transverses
Location and Coefficients Draft/Wave Coefficients
Structural Members/ Draft/Wave Loading Heading Location and
Components Heading Angle Pattern pi pe Angle Loading Pattern pi pe

16. Deck 2/3 design Cargo tank full, Bi —

Transverses: draft/60° adjacent tanks
Tanker without empty
cross ties
(5C-1-4/Figure
2A-a, 5C-1-4/
Figure 2A-b,
5C-1-4/Figure
2A-c & 5C-1-4/
Figure 2A-f)
and, tankers with
cross tie in
center cargo
tanks, (5C-1-4/
Figure 2A-e)
Tanker with 2/3 design Cargo tank full, Ci —
cross ties in draft/90° adjacent tanks
wing cargo empty
tanks
(5C-1-4/
Figure 2A-d)
17. Deck girders 2/3 design Cargo tank full, Ai — 2/3 design Cargo tank full, Bi —
draft/0° adjacent tanks draft/60° adjacent tanks
empty empty

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 43

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

TABLE 3 (continued)
Design Pressure for Local and Supporting Members (2001)
Notes
1 (1 July 2005) For calculating pi and pe, the necessary coefficients are to be determined based on the
following designated groups:
a) For pi

Ai: wv = 0.75, wl(fwd bhd) = 0.25, wl(aft bhd) = −0.25, wt = 0.0, cφ= −0.35, cθ = 0.0

Bi: wv = 0.4, wl(fwd bhd) = 0.2, wl(aft bhd) = −0.2, wt (starboard) = 0.4, wt (port) = −0.4, cφ=
−0.3, cθ = 0.3
Ci : wv = 0.25, wl = 0, wt (starboard) = 0.75, wt (port) = −0.75, cφ= 0.0, cθ = 1.0

Di: wv = −0.75, wl (fwd bhd) = 0.25, wt = 0.0, cφ = −0.35, cθ = 0.0

Ei: wv = 0.4, wl (fwd bhd) = 0.2, wt (centerline) = 0.4, cφ= −0.3, cθ = −0.3

Fi: wv = 0.4, wl (fwd bhd) = 0.2, wl (aft bhd) = −0.2, wt (starboard) = −0.4, wt (port) = 0.4, cφ =
−0.3, cθ = −0.3
Gi: wv = 0.25, wl = 0, wt (starboard) = −0.75, wt (port) = 0.75, cφ = 0.0, cθ = −1.0
b) For pe

Ae: klo = 1.0, ku = 1.0, kc = −0.5

Be: klo = 1.0
2 (1997) For structures within 0.4L amidships, the nominal pressure is to be calculated for a tank located
amidships. Each cargo tank or ballast tank in the region should be considered as located amidships, as
shown in 5C-1-3/Figure 8.
3 (1 July 2000) In calculation of the nominal pressure, ρ g of the fluid cargoes is not to be taken less than
1.005 N/cm2-m (0.1025 kgf/cm2-m, 0.4444 lbf/in2-ft).
4 For structural members 4 and 6 to 10, sloshing pressures are to be considered in accordance with
5C-1-3/11.3. For calculation of sloshing pressures, refer to 5C-1-3/11.5 with ρ g not less than
1.005 N/cm2-m (0.1025 kgf/cm2-m, 0.4444 lbf/in2-ft).

44 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

7 Nominal Design Loads (1995)

7.1 General
The nominal design loads specified below are to be used for determining the required scantlings of hull
structures in conjunction with the specified permissible stresses given in Section 5C-1-4.

7.3 Hull Girder Loads – Longitudinal Bending Moments and Shear Forces (1995)
7.3.1 Total Vertical Bending Moment and Shear Force
The total longitudinal vertical bending moments and shear forces may be obtained from the following
equations:
Mt = Msw + ku kcMw kN-m (tf-m, Ltf-ft)
Ft = Fsw + ku kcFw kN (tf, Ltf)
where
Msw and Mw are the still-water bending moment and wave-induced bending moment, respectively,
as specified in 3-2-1/3.7 for either hogging or sagging conditions.
Fsw and Fw are the still-water and wave-induced shear forces, respectively, as specified in 3-2-1/3.9
for either positive or negative shears.
ku is a load factor and may be taken as unity unless otherwise specified.
kc is a correlation factor and may be taken as unity unless otherwise specified.
For determining the hull girder section modulus for 0.4L amidships, as specified in 5C-1-4/3, the
maximum still-water bending moments, either hogging or sagging, are to be added to the hogging
or sagging wave bending moments, respectively. Elsewhere, the total bending moment may be
directly obtained based on the envelope curves, as specified in 5C-1-3/3.1 and 5C-1-3/5.1.
For this purpose, ku = 1.0, and kc = 1.0

7.3.2 Horizontal Wave Bending Moment and Shear Force

For non-head sea conditions, the horizontal wave bending moment and the horizontal shear force,
as specified in 5C-1-3/5.3, are to be considered as additional hull girder loads, especially for the
design of the side shell and inner skin structures. The effective horizontal bending moment and
shear force, MHE and FHE, may be determined by the following equations:
MHE = k u k c MH kN-m (tf-m, Ltf-ft)
FHE = ku kc FH kN (tf, Ltf)
where ku and kc are a load factor and a correlation factor, respectively, which may be taken as
unity unless otherwise specified.

7.5 Local Loads for Design of Supporting Structures (1 July 2000)

In determining the required scantlings of the main supporting structures, such as girders, transverses,
stringers, floors and deep webs, the nominal loads induced by the liquid pressures distributed over both
sides of the structural panel within the tank boundaries should be considered for the worst possible load
combinations. In general, considerations should be given to the following two loading cases accounting for
the worst effects of the dynamic load components.
i) Maximum internal pressures for a fully filled tank with the adjacent tanks empty and minimum
external pressures, where applicable.
ii) Empty tank with the surrounding tanks full and maximum external pressures, where applicable.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 45

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

Taking the side shell supporting structure as an example, the nominal loads may be determined from either:
i) pi = ksρ g (η + ku hd) max. and
pe = ρ g (hs + ku hde) min.
ii) pi = 0 and
pe = ρ g (hs + ku hde) max.
where
ku = 1.0

ρ g, η, hd, hs, hde, ks are as defined in 5C-1-3/5.5 and 5C-1-3/5.7.

Specific information required for calculating the nominal loads are given in 5C-1-3/Table 3 for various
structural members and configurations.

7.7 Local Pressures for Design of Plating and Longitudinals (1995)

In calculating the required scantlings of plating, longitudinals and stiffeners, the nominal pressures should
be considered for the two load cases given in 5C-1-3/7.5, using ku = 1.1 for pi and pe instead of ku = 1.0 as
shown above.
The necessary details for calculating pi and pe are given in 5C-1-3/Table 3.

9 Combined Load Cases

9.1 Combined Load Cases for Structural Analysis (2001)

For assessing the strength of the hull girder structure and in performing a structural analysis as outlined in
Section 5C-1-5, the eight combined load cases specified in 5C-1-3/Table 1 are to be considered. Additional
combined load cases may be required as warranted. The loading patterns are shown in 5C-1-3/Figure 1 for
three cargo tank lengths. The necessary correlation factors and relevant coefficients for the loaded tanks
are also given in 5C-1-3/Table 1. The total external pressure distribution including static and hydrodynamic
pressure is illustrated in 5C-1-3/Figure 6.

9.3 Combined Load Cases for Failure Assessment (1995)

For assessing the failure modes with respect to material yielding, buckling and ultimate strength, the following
combined load cases shall be considered.
9.3.1 Ultimate Strength of Hull Girder
For assessing ultimate strength of the hull girder, the combined effects of the following primary
and local loads are to be considered.
9.3.1(a) Primary Loads, Longitudinal Bending Moments in Head Sea Conditions. (MH = 0, FH = 0)
Mt = Ms + kukc Mw, ku = 1.15, kc = 1.0 hogging and sagging
Ft = Fs + ku kc Fw, ku = 1.15, kc = 1.0 positive and negative
9.3.1(b) Local Loads for Large Stiffened Panels. Internal and external pressure loads as given for
L.C. No. 1 and L.C. No. 2 in 5C-1-3/Table 1.
9.3.2 Yielding, Buckling and Ultimate Strength of Local Structures
For assessing the yielding, buckling and ultimate strength of local structures, the eight combined
load cases as given in 5C-1-3/Table 1 are to be considered.
9.3.3 Fatigue Strength
For assessing the fatigue strength of structural joints, the eight combined load cases given in 5C-1-3/9.1
are to be used for a first level fatigue strength assessment as outlined in Appendix 5C-1-A1
“Guide for the Fatigue Assessment of Tankers.”

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

11 Sloshing Loads

11.1 General (1995)

11.1.1 (2002)
Except for tanks that are situated wholly within the double side or double bottom, the natural
periods of liquid motions and sloshing loads are to be examined in assessing the strength of
boundary structures for all cargo or ballast tanks which will be partially filled between 20% and
90% of tank capacity. The sloshing pressure heads given in this subsection may be used for
determining the strength requirements for the tank structures. Alternatively, sloshing loads may be
determined by model experiments or by numerical simulation using three dimensional flow
analysis. Methodology and procedures of tests and measurements or analysis methods are to be
fully documented and referenced. They are to be submitted for review.
11.1.2
The effects of impulsive sloshing pressures on the design of the main supporting structures of tank
transverse and longitudinal bulkheads will be subject to special consideration.

11.3 Strength Assessment of Tank Boundary Structures

11.3.1 Tank Length and Pitch Induced Sloshing Loads (2002)
Tanks of length 54 m (177 ft) or greater are to satisfy requirements of either of the preventative
measures given in 5C-1-3/11.3.3 or 5C-1-3/11.3.4. Where the tank has smooth surfaces, one or
more swash bulkheads are to be fitted. Structural reinforcement is to be provided to the tank ends,
when the calculated pressure is higher than the pressure, pi, as specified in 5C-1-4/13.
Tanks of length 54 m (177 ft) or greater that have ring webs are to have a partial non-tight
bulkhead (i.e. non-full depth swash bulkhead) to eliminate the possibility of resonance at all filling
levels. The partial non-tight bulkhead may be waived if it can be demonstrated through the
application of model experiments or numerical simulation using three-dimensional flow analysis
that sloshing impacts do not occur. The height of the swash bulkhead is to be determined on the
basis of calculation using three-dimensional flow analysis as described in 5C-1-3/11.1.1
Where the tank length is less than 54 m (177 ft), and if either of the preventative measures given
in 5C-1-3/11.3.3 or 5C-1-3/11.3.4 is not satisfied, the tank boundary structures are to be designed
in accordance with 5C-1-4/13 to withstand the sloshing pressures specified in 5C-1-3/11.5.
11.3.2 Roll Induced Sloshing Loads (2002)
Tanks that do not satisfy either of the preventative measures given in 5C-1-3/11.3.3 or 5C-1-3/11.3.4,
with respect of roll resonance, are to have their tank boundary structures designed in accordance
with 5C-1-4/13 to withstand the sloshing pressures specified in 5C-1-3/11.5.
11.3.3 (1997)
For long or wide cargo tanks, non-tight bulkheads or ring webs or both are to be designed and
fitted to eliminate the possibility of resonance at all filling levels.
Long tanks have length, l, exceeding 0.1L. Wide tanks have width, b, exceeding 0.6B.
11.3.4
For each of the anticipated loading conditions, the “critical” filling levels of the tank should be
avoided so that the natural periods of fluid motions in the longitudinal and transverse directions
will not synchronize with the natural periods of the vessel’s pitch and roll motions, respectively. It
is further recommended that the natural periods of the fluid motions in the tank, for each of the
anticipated filling levels, be at least 20% greater or smaller than that of the relevant ship’s motion.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 47

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

The natural period of the fluid motion, in seconds, may be approximated by the following equations:
Tx = (βT le)1/2/k in the longitudinal direction

Ty = (βL be)1/2/k in the transverse direction

where
le = effective length of the tank, as defined in 5C-1-3/11.5.1, in m (ft)
be = effective breadth of the tank, as defined in 5C-1-3/11.5.1 in m (ft)

k = [(tanh H1)/(4π/g)]1/2

H1 = π dl/le or π db /be
βT, βL, dl and db are as defined in 5C-1-3/11.5.1. The natural periods given in 5C-1-3/5.7 for pitch
and roll of the vessel, Tp and Tr, using the actual GM value, if available, may be used for this
purpose.

11.5 Sloshing Pressures (1995)

11.5.1 Nominal Sloshing Pressure (1 July 2005)
For cargo tanks with filling levels within the critical range specified in 5C-1-3/11.3.2, the internal
pressures pis, including static and sloshing pressures, positive toward tank boundaries, may be
expressed in terms of equivalent liquid pressure head, he, as given below:
pis = ksρ ghe ≥ 0 in N/cm2 (kgf/cm2, lbf/in2)
where
ks = load factor as defined in 5C-1-3/5.7.2(a)
he = cmhm + ku hc for y below filling level dm (cmhm need not exceed h and he
need not exceed he calculated at y = 0.15 for y below 0.15h)
= ku[hc + (ht − hc)(y − dm)/(h − dm)] for y above dm
cm = coefficient in accordance with 5C-1-3/Figure 10
hm = static head, taken as the vertical distance, in m (ft), measured from the filling
level, dm, down to the point considered. dm, the filling level for maximum hc
calculated with Cφs and Cθs equal to 1.0, should not be taken less than 0.55h.
dm = filling level, in m (ft), as shown in 5C-1-3/Figure 9
ku = load factor, and may be taken as unity unless otherwise specified.
hc = maximum average sloshing pressure heads, in m (ft), to be obtained from
calculations as specified below for at least two filling levels, 0.55h and the
one closest to the resonant period of ship’s motions, between 0.2h and 0.9h.
hc may be taken as constant over the tank depth, h (See 5C-1-3/Figure 9)
ht = sloshing pressure heads for upper bulkhead, in m (ft), to be obtained from
calculation below
h = depth of tank, in m (ft)
y = distance, in m (ft), measured from the tank bottom to the point considered
ρ g is as defined in 5C-1-3/5.7.2.

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

The values of hc and ht may be obtained from the following equations:

hc = kc (Cφs hl2 + Cθs h b2 )1/2 in m (ft)

ht = kc (Cφs h t2l + Cθs h tb2 )1/2 in m (ft)

where
kc = correlation factor for combined load cases, and may be taken as unity unless
otherwise specified.
hl = φesle CtlβT [0.018 + Cfl (1.0 − dl/Hl)/φes]dl/Hl m (ft)

hb = θesbe CtbβL [0.016 + Cfb (1.0 − db/Hb)/ θes]db/Hb m (ft)

Cφs and Cθs are the weighted coefficients as given in 5C-1-3/Figure 10.
where
βT represents β for transverse bulkheads and βL represents β for the longitudinal bulkheads.
φes = 0.71 cφ φ

θes = 0.71 cθ θ

φ and θ are as defined in 5C-1-3/5.7.1.

le = effective tank length that accounts for the effect of deep ring-web frames, in
m (ft)

= β T* 2 l
be = effective tank width that accounts for the effect of deep ring-web frames, in
m (ft)

= β L* 2 b
β* = 1.0 for tanks without deep ring webs,
= 0.25[4.0 − (1 − α*) − (1 − α*)2] for α* to be determined at do,

β T* represents β* for transverse bulkheads.

β L* represents β* for longitudinal bulkheads.

β = (βo)(βs) ≥ 0.5
βT represents β for transverse bulkheads.
βL represents β for longitudinal bulkheads.
βo = 1.0 for tanks without a swash bulkhead
= 0.25[4.0 − (1 − αo) − (1 − αo)2] for tanks with a swash bulkhead
βs = 1.0 for boundary bulkheads that:
i) do not contain any deep horizontal girder; or
ii) do contain deep horizontal girders but with an opening ratio, αs, less
than 0.2 or greater than 0.4
= 0.25[4.0 − (1 − αs) − (1 − αs)2] for bulkheads with deep horizontal girders
having an opening ratio, αs, between 0.2 and 0.4
α = opening ratio (see 5C-1-3/Figure 11)

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 49

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

For αo 5C-1-3/Figure 12(1), opening ratios of swash bulkheads, shall be used for all filling levels
considered. Also, 5C-1-3/Figure 12(2), local opening ratio for do = 0.7h, bounded by the range
between 0.6h and 0.9h, shall be considered for openings within the range. The smaller of the two
opening ratios calculated, based on 5C-1-3/Figure 12(1) and 5C-1-3/Figure 12(2) for this filling
level, shall be used as the opening ratio.
For α*, 5C-1-3/Figure 12(3), opening ratio of deep ring-webs, filling level do shall be used.
For αs, 5C-1-3/Figure 12(4), opening ratio of a deep horizontal girder on a boundary bulkhead, is
applicable to a filling level just above the horizontal girder in the zones illustrated in the figure.
Not to be considered for do = 0.7h, unless a sizable girder is installed between 0.7h and h. Also not
to be considered if opening area in the girder is less than 20% or greater than 40% of the area of
the girder (i.e., αs = 1)
Cfl = 0.792[dl/(βT le)]1/2 + 1.98

Cfb = 0.704[db/(βL be)]1/2 + 1.76

Ctl = 0.9 xo1/[1 + 9(1 − xo)2] ≥ 0.25

xo = Tx /Tp

xo1 = xo if xo ≤ 1.0
= 1/xo if xo > 1.0

Ctb = 0.9 yo1/[1 + 9(1 − yo)2] ≥ 0.25

yo = Ty /Tr If roll radius of gyration is not known, 0.39B may be used in the
calculation of Tr
yo1 = yo if yo ≤ 1.0
= 1/yo if yo > 1.0
Tx and Ty are as defined in 5C-1-3/11.3.4.
Tp and Tr are as defined in 5C-1-3/5.7.
do = filling depth, in m (ft)

dl = do − dl1[(n/(n + 4)]1/2 − 0.45dl2, and ≥ 0.0

db = do − db1[m/(m + 4)]1/2 − 0.45db2, and ≥ 0.0

Hl = h − dl1[n/(n + 4)]1/2 − 0.45dl2

Hb = h − db1[m/(m + 4)]1/2 − 0.45db2

dl1 = height of deep bottom transverses measured from the tank bottom,
(5C-1-3/Figure 13), in m (ft)
dl2 = bottom height of the lowest openings in non-tight transverse bulkhead measured
above the tank bottom or top of bottom transverses (5C-1-3/Figure 13), in m (ft)
n = number of deep bottom transverses in the tank
db1 = height of deep bottom longitudinal girders measured from the tank bottom
(5C-1-3/Figure 13), in m (ft)
db2 = bottom height of the lowest openings in non-tight longitudinal bulkhead
measured above the tank bottom, or top of bottom longitudinal girders
(5C-1-3/Figure 13), in m (ft)
m = number of deep bottom longitudinal girders in the tank

50 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

ls (bs) shall be used in place of le (be) for a filling level below the completely solid portion of the
nontight bulkhead, i.e., the region below the lowest opening, (5C-1-3/Figure 13), where ls (bs) is
taken as the distance bounded by the solid portion of the nontight bulkhead below the lowest
opening and the tight bulkhead. dl, Hl and db, Hb need not consider the effect of dl2 and db2,
respectively.
htl = 0.0068 β T′ l e C t′l (φes + 40) (φes)1/2 m (ft)

htb = 0.0055 β L′ be C tb′ (θes + 35) (θes)1/2 m (ft)

where
Ct′l and C tb′ are Ctl and Ctb for hm = 0.70h; β T′ and β L′ correspond to β for do = 0.7h; φes and θes
are as defined previously.
Cφs and Cθs are weighted coefficients, as given in 5C-1-3/Figure 10.
htl shall not be less than hp; htb shall not be less than hr

hp = l sin (φes)

hr = b sin (θes)

11.5.2 Sloshing Loads for Assessing Strength of Structures at Tank Boundaries

11.5.2(a) In assessing the strength of tank boundary supporting structures, the two combined load
cases with loading pattern shown in 5C-1-3/Figure 14, with the specified sloshing loads shown in
5C-1-3/Table 2 for the respective side on which the horizontal girder is located, are to be
considered when performing a 3D structural analysis.
11.5.2(b) In assessing the strength of plating and stiffeners at tank boundaries, local bending of
the plating and stiffeners with respect to the local sloshing pressures for structural members/elements
is to be considered in addition to the nominal loadings specified for the 3D analysis in 5C-1-3/11.5.2(a)
above. In this regard, ku should be taken as 1.15 instead of 1.0, shown in 5C-1-3/11.5.2(a) above
for the combined load cases, to account for the maximum pressures due to possible non-uniform
distribution.
11.5.3 Sloshing Loads Normal to the Web Plates of Horizontal and Vertical Girders
In addition to the sloshing loads acting on the bulkhead plating, the sloshing loads normal to the
web plates of horizontal and vertical girders are to be also considered for assessing the strength of
the girders. The magnitude of the normal sloshing loads may be approximated by taking 25% of hc
or ht for ku = 1.0, whichever is greater, at the location considered.

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

FIGURE 9
Vertical Distribution of Equivalent
Slosh Pressure Head, he (1995)

kuht

kuhc +
[ ku (ht - hc) (y - dm) / (h - dm) ]

dm he y

kuhc Cmhm

52 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

FIGURE 10
Horizontal Distribution of Simultaneous Slosh Pressure
Heads, hc (φs θs) or ht (φs θs) (1995)

Cφ s = 0.0
Cm = 0.5 Cm = 1.0 Cθ s = 0.0

AFT BHD Cφ s = 1.0

Cm = 1.25
Cθ s = 0.0
Cφ s = 0.0
Cθ s = 1.0
Cm = 1.0 Cm = 1.25 Cm = 1.5
Cφ s = 0.0 Cφ s = 1.0
Cθ s = 0.0 Cθ s = 1.0
L.C. S-1

Cφ s = 1.0 Cφ s = 0.0
Cθ s = 1.0 Cθ s = 0.0
Cm = 1.5 Cm = 1.25 Cm = 1.0
Cφ s = 0.0
Cθ s = 1.0
FWD BHD

Cφ s = 1.0 Cm = 1.25
Cθ s = 0.0

Cm = 1.0 Cm = 0.5
Cφ s = 0.0
L.C. S-2
Cθ s = 0.0

Note: hc may be taken as zero for the deck and inner bottom

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 53

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

FIGURE 11
Definitions for Opening Ratio, α (1995)

α = A1 + A2 α = A1 + A2 + A3
A1 + A2 + B A1 + A2 + A3 + B
A3 A4

A3
A1 A2
do

A1 A2
B B
B: wetted portion of swash bulkhead

FIGURE 12
Opening Ratios (1995)

h
do

Deep Horizontal Grider

L - Type Full Swash

(1) dw
A
affected zones
45°

0.6h - 0.9h Deep Ring-Web Frame

B
dw
C

A+B
αs =
A+B+C dw
0.7h do

(2) (3)

(1) – (3) Opening Ratios of Nontight Bulkheads (4) Opening Ratio of Deep Horizontal Girders Boundary
and Deep Ring-Webs Bulkheads

54 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

FIGURE 13
Dimensions of Internal Structures (1995)

h
dl 2
dl1
ls

h
db2

db1
bs

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

FIGURE 14
Loading Patterns for Sloshing Loads Cases (1997)
Type A: Where the Horizontal Girder is on the Aft Side of Transverse Bulkhead

a. Load Case S-1; 1/2 Design Draft b. Load Case S-2; 1/2 Design Draft

Type B: Where the Horizontal Girder is on the Forward Side of Transverse Bulkhead

a. Load Case S-1; 1/2 Design Draft b. Load Case S-2; 1/2 Design Draft

56 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

13 Impact Loads (2000)

13.1 Impact Loads on Bow (2000)

For tankers possessing significant bowflare or with a heavy ballast draft forward less than 0.04L, the
bowflare and/or bottom slamming loads are to be considered for assessing the strength of the side and
bottom plating and associated stiffening system in the forebody region.
13.1.1 Bow Pressure
When experimental data or direct calculation are not available, nominal wave-induced bow pressures
above LWL in the region from the forward end to the collision bulkhead may be obtained from the
following equation:

Pbij = kCkCij Vij2 sin γij kN/m2 (tf/m2, Ltf/ft2)

where
k = 1.025 (0.1045, 0.000888)
Cij = {1 + cos2 [90(Fbi – 2aij)/Fbi]}1/2

Vij = ω1V sin αij + ω2(L)1/2

ω1 = 0.515 (1.68) for m (ft)

ω2 = 1.0 (1.8)
V = 75% of the design speed, Vd, in knots. V is not to be taken less than 10
knots. Vd is defined in 3-2-14/3.1.
γij = local bow angle measured from the horizontal, not to be taken less than 50°

= tan-1 (tan βij/cos αij)

αij = local waterline angle measured from the centerline, see 5C-1-3/Figure 15,
not to be taken less than 35°
βij = local body plan angle measure from the horizontal, see 5C-1-3/Figure 15, not
to be taken less than 35°
Fbi = freeboard from the highest deck at side to the load waterline (LWL) at station
i, see 5C-1-3/Figure 15
aij = vertical distance from the LWL to WLj, see 5C-1-3/Figure 15
Ck = 0.7 at collision bulkhead and 0.9 at 0.0125L, linear interpolation for in
between
= 0.9 between 0.0125L and the FP
= 1.0 at and forward of the FP
i, j = station and waterline, to be taken to correspond to the locations as required
by 5C-1-6/3.1.1

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

FIGURE 15
Definition of Bow Geometry (1 July 2008)

WLj A B

α
waterline angle tangent line

B A

CL

CL CL

highest deck

tangent line tangent line

s normal
body plan
body plan
angle
β angle β'
WLj
Fbi
aij

LWL
A-A B-B

13.3 Bottom Slamming (2002)

For tankers with heavy ballast draft forward less than 0.04L but greater than 0.025L, bottom slamming
loads are to be considered for assessing strength of the flat of bottom plating forward and the associated
stiffening system in the fore body region. For this assessment, the heavy ballast draft forward is to be
determined by using segregated ballast tanks only.
13.3.1 Bottom Slamming Pressure
The equivalent bottom slamming pressure for strength formulation and assessment should be
determined based on well-documented experimental data or analytical studies. When these direct
calculations are not available, nominal bottom slamming pressures may be determined by the
following equations:

Psi = kki [ vo2 + MViEni]Ef kN/m2 (tf/m2, Ltf/ft2)

where
Psi = equivalent bottom slamming pressure for section i
k = 1.025 (0.1045, 0.000888)
ki = 2.2 b*/do + α ≤ 40
b* = half width of flat of bottom at the i-th ship station, see 5C-1-3/Figure 16
do = 1/
10 of the section draft at the heavy ballast condition, see 5C-1-3/Figure 16
α = a constant as given in 5C-1-3/Table 4
Ef = f1 ω1 (L)1/2
f1 = 0.004 (0.0022) for m (ft)
where b represents the half breadth at the 1/10 draft of the section, see 5C-1-3/Figure 16. Linear
interpolation may be used for intermediate values.

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

V = 75% of the design speed Vd in knots. V is not to be taken less than 10 knots

vo = co(L)1/2, in m/s (ft/s)

co = 0.29 (0.525) for m (ft)
L = vessel’s length as defined in 3-1-1/3.1
MRi = c1Ai(VL/Cb)1/2
c1 = 0.44 (2.615) for m (ft)
MVi = BiMRi
Ai and Bi are as given in 5C-1-3/Table 5.
2 2
Gei = e[ − (vo / MVi + di / M Ri )]

di = local section draft, in m (ft)

Eni = natural log of ni
ni = 5730(MVi/MRi)1/2 Gei, if ni < 1 then Psi = 0
ω1 = natural angular frequency of the hull girder 2-node vertical vibration of the
vessel in the wet mode and the heavy ballast draft condition, in rad/second. If
not known, the following equation may be used:

= μ [B D3/(ΔS Cb3 L3)]1/2 + co ≥ 3.7

where
μ = 23400 (7475, 4094)
ΔS = Δb[1.2 +B/(3db)]
Δb = vessel displacement at the heavy ballast condition, in kN (tf, Ltf)
db = mean draft of vessel at the heavy ballast condition, in m (ft)
co = 1.0 for heavy ballast draft
L, B and D are as defined in Section 3-1-1.
Cb is as defined in 3-2-1/3.5.

TABLE 4
Values of α (2000)
b/do α b/do α
1.00 0.00 4.00 20.25
1.50 9.00 5.00 22.00
2.00 11.75 6.00 23.75
2.50 14.25 7.00 24.50
3.00 16.50 7.50 24.75
3.50 18.50 25.0 24.75

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

FIGURE 16
Distribution of Bottom Slamming Pressure Along the Section Girth (2000)

centerline

b* do (1/10 draft)

Ps

13.5 Bowflare Slamming (2000)

For vessels possessing bowflare and having a shape parameter Ar greater than 21 m (68.9 ft), in the
forebody region, bowflare slamming loads are to be considered for assessing the strength of the side
plating and the associated stiffening system in the forebody region of the vessel at its scantling draft.
Ar = the maximum value of Ari in the forebody region
Ari = bowflare shape parameter at a station i forward of the quarter length, up to the FP of
the vessel, to be determined between the load waterline (LWL) and the upper
deck/forecastle, as follows:
= (bT/H)2 ∑bj[1 + (sj /bj)2]1/2, j = 1, n; n ≥ 3
where
n = number of segments

bT = ∑b j

H = ∑s j

bj = local change (increase) in beam for the j-th segment at station i (see 5C-1-3/Figure 17)
sj = local change (increase) in freeboard up to the highest deck for the j-th segment at
station i forward (see 5C-1-3/Figure 17).
13.5.1 Nominal Bowflare Slamming (1 July 2008)
When experimental data or direct calculation is not available, nominal bowflare slamming pressures
may be determined by the following equations:
Pij = Poij or Pbij as defined below, whichever is greater

Poij = k1(9MRi – hij2 )1/2 kN/m2 (tf/m2, Ltf/ft2)

Pbij = k2 k3 [C2 + KijMVi(1 + Eni)] kN/m2 (tf/m2, Ltf/ft2)

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

where
k1 = 9.807 (1, 0.0278)
k2 = 1.025 (0.1045, 0.000888)

k3 = 1 for hij ≤ hb*

= 1 + (hij/ hb* – 1)2 for hb* < hij < 2 hb*

= 2 for hij ≥ 2 hb*

hij = vertical distance measured from the load waterline (LWL) at station i to WLj
on the bowflare. The value of hij is not to be taken less than hb* . Pbij at a
location between LWL and hb* above LWL need not be taken greater than
*
pbij .

hb* = 0.005(L – 130) + 3.0 (m) for L < 230 m

= 0.005(L – 426.4) + 9.84 (ft) for L < 754 ft
= 7.143 × 10-3(L – 230) + 3.5 (m) for 230 m ≤ L < 300 m
= 7.143 × 10-3(L – 754.4) +11.48 (ft) for 754 ft ≤ L< 984 ft
= 4.0 m (13.12 ft) for L ≥ 300 m (984 ft)
*
pbij = Pbi* β i* β ij′

Pbi* = Pbij at hb* above LWL

C2 = 39.2 m (422.46 ft)
Eni = natural log of nij

nij = 5730(MVi/MRi)1/2 Gij ≥ 1.0

Gij = e
(−hij2 / M Ri )

MVi = BiMRi, where Bi is given in 5C-1-3/Table 5.

MRi = c1 Ai (VL/Cb)1/2, where Ai is given in 5C-1-3/Table 5, if 9MRi < hij2 , then Poij
=0
c1 = 0.44 (2.615) for m (ft)
V = as defined in 5C-5-3/11.1
L = as defined in 3-1-1/3.1, in m (ft)
Cb = as defined in 3-2-1/3.5.1 and not to be less than 0.6

Kij = fij [rj/(bbij + 0.5hij)]3/2 [lij/rj] [1.09 + 0.029V − 0.47Cb]2

fij = [90/ β ij′ – 1]2 [tan2 ( β ij′ )/9.86] cos γ

β ij′ = normal local body plan angle

βij = local body plan angle measured from the horizontal, in degrees, need not be
taken greater than 75 degrees, see 5C-1-3/Figure 15

β i* = β ij′ at hb* above LWL

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

rj = (MRi)1/2

bbij = bij − bi0 > 2.0 m (6.56 ft)

bij = local half beam of location j at station i
bi0 = load waterline half beam at station i
lij = longitudinal distance of WLj at station i measured from amidships, based on
the scantling length
γ = ship stem angle at the centerline measured from the horizontal,
5C-1-3/Figure 18, in degrees, not to be taken greater than 75 degrees

TABLE 5
Values of Ai and Bi * (2000)
Ai Bi
-0.05L 1.25 0.3600
FP 1.00 0.4000
0.05L 0.80 0.4375
0.10L 0.62 0.4838
0.15L 0.47 0.5532
0.20L 0.33 0.6666
0.25L 0.22 0.8182
0.30L 0.22 0.8182
* Linear interpolation may be used for intermediate values.

62 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

FIGURE 17
Definition of Bowflare Geometry for Bowflare Shape Parameter (2000)

highest deck b4

s4

s3
b3
s2
βij
(body plan angle)

b2

s1

b1
LWL
centerline

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 63

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 3 Load Criteria 5C-1-3

FIGURE 18
Ship Stem Angle, γ (2000)
F.P.

Stem Angle γ

13.5.2 Simultaneous Bowflare Slamming Pressure

For performing structural analyses to determine overall responses of the hull structures, the spatial
distribution of instantaneous bowflare slamming pressures on the forebody region of the hull may
be expressed by multiplying the calculated maximum bowflare slamming pressures, Pij, at forward
ship stations by a factor of 0.71 for the region between the stem and 0.3L from the FP.

64 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

PART Section 4: Initial Scantling Criteria

5C
CHAPTER 1 Vessels Intended to Carry Oil in Bulk (150 meters
(492 feet) or more in Length)

SECTION 4 Initial Scantling Criteria

1 General

1.1 Strength Requirement (1995)

This section specifies the minimum strength requirements for hull structure with respect to the determination
of initial scantlings, including the hull girder, shell and bulkhead plating, longitudinals/ stiffeners and main
supporting members. Once the minimum scantlings are determined, the strength of the resulting design is
to be assessed in accordance with Section 5C-1-5. The assessment is to be carried out by means of an
appropriate structural analysis as per 5C-1-5/9, in order to establish compliance with the failure criteria in
5C-1-5/3. Structural details are to comply with 5C-1-4/1.5.
The requirements for hull girder strength are specified in 5C-1-4/3. The required scantlings of double
bottom structures, side shell and deck, and longitudinal and transverse bulkheads are specified in 5C-1-4/7
through 5C-1-4/17 below. 5C-1-4/Figure 1 shows the appropriate subsections giving scantling requirements
for the various structural components of typical double hull tankers. For hull structures beyond 0.4L amidships,
the initial scantlings are determined in accordance with Section 5C-1-6.

1.3 Calculation of Load Effects (1995)

Equations giving approximate requirements are given in 5C-1-4/7 through 5C-1-4/13 for calculating the
maximum bending moments and shear forces for main supporting members clear of the end brackets, and
axial loads for cross ties for typical structural arrangements and configurations (5C-1-4/Figure 2A and
5C 1-4/Figure 2B). For designs with different structural configurations, these local load effects may be
determined from a 3D structural analysis at the early design stages, as outlined in 5C-1-5/9, for the
combined load cases specified in 5C-1-3/9, excluding the hull girder load components. In this regard, the
detailed analysis results are to be submitted for review.

1.5 Structural Details (1995)

The strength criteria specified in this Section and Section 5C-1-6 are based on assumptions that all
structural joints and welded details are properly designed and fabricated and are compatible with the
anticipated working stress levels at the locations considered. It is critical to closely examine the loading
patterns, stress concentrations and potential failure modes of structural joints and details during the design
of highly stressed regions. In this exercise, failure criteria specified in 5C-1-5/3 may be used to assess the
adequacy of structural details.

1.7 Evaluation of Grouped Stiffeners (1 July 2005)

Where several members in a group with some variation in requirement are selected as equal, the section
modulus requirement may be taken as the average of each individual requirement in the group. However,
the section modulus requirement for the group is not to be taken less than 90% of the largest section
modulus required for individual stiffeners within the group. Sequentially positioned stiffeners of equal
scantlings may be considered a group.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 65

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

FIGURE 1
Scantling Requirement Reference by Subsection (1995)
5C-1-4/3.1 5C-1-4/11.3.1 & 5C-1-4/11.5.2
5C-1-4/9.5
5C-1-4/9.3

L
C

5C-1-4/11.5.1 & 5C-1-4/11.5.2

5C-1-4/11.7

5C-1-4/5.3
5C-1-4/9.1
5C-1-4/13.3 (plate)
5C-1-4/17 (corrugated)

5C-1-4/15.7.1
5C-1-4/15.5.1
5C-1-4/11.9

5C-1-4/13.5

5C-1-4/9.5 5C-1-4/13.5

5C-1-4/5.5 5C-1-4/13.3
5C-1-4/13.1 5C-1-4/7.3.2

5C-1-4/7.7.4
5C-1-4/7.7.2 L
C

5C-1-4/7.5

5C-1-4/7.3.1 5C-1-4/7.7.3 & 5C-1-4/7.7.4

5C-1-4/7.7.3
For main supporting members, also see
5C-1-4/11.9 & 5C-1-4/11.11 for minimum
web depth and thickness requirements.

66 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

FIGURE 2A
Definitions of Spans (A) (1995)

= = = =
= =

sg sg
lt ls lb lt ls
l
l

L
C
L
C

a. b.

l l
lt
he

lt he
lt lb
lb ls ls
l

L
C L
C
c. d.

l l l lt
lt l

lb lt lt
ls lb ls

L
C L
C

e. f

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 67

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

FIGURE 2B
Definitions of Spans (B) (1995)

hU
hU

lb
l l

hL
hL

L
C
a. Side Transverve and Vertical
Web on Longitudinal Bulkhead

l
lb

he

L
C

b. Horizontal Girder on
Transverse Bulkhead

he

hU

ha
lg
lst l
l

hL

c. Deck Girder and Vertical Web

on Transverse Bulkhead

68 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

3 Hull Girder Strength

3.1 Hull Girder Section Modulus (1995)

3.1.1 Hull Girder Section Modulus Amidships
The required hull girder section modulus amidships is to be calculated in accordance with 3-2-1/3.7,
3-2-1/5 and 3-2-1/9. For the assessment of ultimate strength as specified in Section 5C-1-5 and the
determination of initial net structural scantlings, the net hull girder section modulus amidships,
SMn, is to be calculated in accordance with 5C-1-4/3.1.2 below.

3.1.2 Effective Longitudinal Members

The hull girder section modulus calculation is to be carried out in accordance with 3-2-1/9, as
modified below. To suit the strength criteria based on a “net” ship concept, the nominal design
corrosion values specified in 5C-1-2/Table 1 are to be deducted in calculating the net section
modulus, SMn.

3.3 Hull Girder Moment of Inertia (1995)

The hull girder moment of inertia is to be not less than required by 3-2-1/3.7.2.

5 Shearing Strength (1997)

5.1 General
The net thickness of the side shell and longitudinal bulkhead plating is to be determined based on the total
vertical shear force, Ft, and the permissible shear stress, fs, given below, where the outer longitudinal
bulkheads (inner skin) are located no further than 0.075B from the side shell.
The nominal design corrosion values as given in 5C-1-2/Table 1 for the side shell and longitudinal bulkhead
plating are to be added to the “net” thickness thus obtained.
Ft = FS + FW kN (tf, Ltf)
t = Fm/I fs cm (in.)
where
FS = still-water shear force based on the still-water shear force envelope curve for all
anticipated loading conditions in accordance with 3-2-1/3.3, at location considered, in
kN (tf, Ltf).
FW = vertical wave shear force, as given in 3-2-1/3.5.3, in kN (tf, Ltf). FW for in-port
condition may be taken as zero.
t = ts or ti (see 5C-1-4/5.3 and 5C-1-4/5.5)
F = FtDs or (Ft + Ri)Di (see 5C-1-4/5.3 and 5C-1-4/5.5 below)

m = first moment of the “net” hull girder section, in cm3 (in3), about the neutral axis, of
the area between the vertical level at which the shear stress is being determined and
the vertical extremity of the section under consideration
I = moment of inertia of the “net” hull girder section at the position considered, in cm4 (in4)
fs = 11.96/Q kN/cm2 (1.220/Q tf/cm2, 7.741/Q Ltf/in2) at sea

= 10.87/Q kN/cm2 (1.114/Q tf/cm2, 7.065/Q Ltf/in2) in port

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

Q = material conversion factor

= 1.0 for ordinary strength steel
= 0.78 for Grade H32 steel
= 0.72 for Grade H36 steel
= 0.68 for Grade H40 steel
For the purpose of calculating required thickness for hull girder shear, the sign of Ft may be disregarded
unless algebraic sum with other shear forces, such as local load components, is appropriate.

5.3 Net Thickness of Side Shell Plating

ts ≥ Ft Ds m/I fs cm (in.)
where
Ds = shear distribution factor for side shell, as defined in 5C-1-4/5.3.1, 5C-1-4/5.3.2 or
5C-1-4/5.3.3 below.
Ft, m, I and fs are as defined in 5C-1-4/5.1 above.

5.3.1 Shear Distribution Factor for Tankers with Two Outer Longitudinal Bulkheads (inner skin only)
Ds = 0.384 − 0.167Aob/As − 0.190 bs/B
where
Aob = total projected area of the net outer longitudinal bulkhead (inner skin) plating
above inner bottom (one side), in cm2 (in2)
As = total projected area of the net side shell plating (one side), in cm2 (in2)
bs = distance between outer side longitudinal bulkhead (inner skin) and side shell,
in m (ft)
B = breadth of the vessel, in m (ft), as defined in 3-1-1/5.
5.3.2 Shear Distribution Factor for Tankers with Two Outer Longitudinal Bulkheads and a
Centerline Swash or Oil-tight Longitudinal Bulkhead
Ds = 0.347 − 0.057Acb /As − 0.137 Aob /As − 0.070bs /B
where
Acb = total area of the net centerline longitudinal bulkhead plating above inner
bottom, in cm2 (in2)
As, Aob, bs and B are as defined in 5C-1-4/5.3.1 above.

5.3.3 Shear Distribution Factor for Tankers with Two Outer and Two Inner Longitudinal Bulkheads
Ds = 0.330 − 0.218Aob /As − 0.043bs /B
where
As, Aob, bs and B are as defined in 5C-1-4/5.3.1 above.

5.5 Thickness of Longitudinal Bulkheads

ti ≥ (Ft + Ri)Di m/I fs cm (in.)
where
Di = shear distribution factor
Ri = local load correction

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

i = ob for outer longitudinal bulkhead (inner skin)

= ib for inner longitudinal bulkhead
= cb for centerline longitudinal bulkhead
Ft, I, m and fs are as defined above.
The other parameters, depending on the configuration of the tanker, are defined in 5C-1-4/5.5.1, 5C-1-4/5.5.2
and 5C-1-4/5.5.3 below.
5.5.1 Tankers with Two Outer Longitudinal Bulkheads (Inner Skin Only)
The net thickness of the outer longitudinal bulkhead plating at the position considered:
tob ≥ FtDobm/I fs cm (in.)
where
Dob = 0.105 + 0.156Aob/As + 0.190bs/B
As, Aob, bs, B, Ft, I, m and fs are defined above.

5.5.2 Tankers with Two Outer Longitudinal Bulkheads and a Centerline Swash or Oil-tight
Longitudinal Bulkhead
5.5.2(a) (1999) The net thickness of the centerline longitudinal bulkhead plating at the position
considered:
tcb ≥ (Ft + Rcb)Dcbm/I fs cm (in.)
where
Rcb = Wc[(2Nwcb kcbI/3Hcb Dcbm) − 1] ≥ 0
*
kcb = 1 + Acb /Acb ≤ 1.9

Dcb = 0.229 + 0.152Acb/As − 0.10Aob/As − 0.198 bs/B

Wc = local load, in kN (tf, Ltf), calculated according to 5C-1-4/5.7 and
5C-1-4/Figure 3a
Nwcb = local load distribution factor for the centerline longitudinal bulkhead

= (0.66Dcb + 0.25) (n − 1)/n

n = total number of transverse frame spaces in the center tank
Hcb = depth of the centerline longitudinal bulkhead above inner bottom, in cm (in.)
*
Acb = total area of the net centerline longitudinal bulkhead plating above the lower
edge of the strake under consideration, in cm2 (in2)
All other parameters are as defined in 5C-1-4/5.3.
5.5.2(b) The net thickness of the outer longitudinal bulkhead plating at the position considered:
tob ≥ Ft Dobm/I fs cm (in.)
where
Dob = 0.106 − 0.093Acb/As + 0.164Aob/As + 0.202bs/B
All other parameters are as defined in 5C-1-4/5.3 and 5C-1-4/5.5.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 71

Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

5.5.3 Tankers with Two Outer and Two Inner Longitudinal Bulkheads
5.5.3(a) The net thickness of the inner longitudinal bulkhead plating at the position considered:
tib ≥ (Ft + Rib)Dibm/I fs cm (in.)
where
Rib = Wc1[(2Nwib1kibI/3HibDibm) − 1] + Wc2[(2Nwib2kibI/3HibDibm) − 1] ≥ 0

kib = 1 + Aib* /Aib ≤ 1.9

Dib = 0.058 + 0.173Aib/As − 0.043bs/B

Wc1, Wc2 = local load, in kN (tf, Ltf), calculated according to 5C-1-4/5.7 and
5C-1-4/Figure 3b
Aib = total area of the net inner longitudinal bulkhead plating above inner bottom,
in cm2 (in2)
Aib* = total area of the net inner longitudinal bulkhead plating above the lower edge
of the strake under consideration, in cm2 (in2)
Nwib1, Nwib2 = local load distribution factor for inner longitudinal bulkhead

Nwib1 = (0.49Dib + 0.18)(n − 1)/n for local load Wc1

Nwib2 = (0.60Dib + 0.10)(n − 1)/n for local load Wc2

Hib = depth of the inner longitudinal bulkhead above inner bottom, in cm (in.)
All other parameters are as defined above.
5.5.3(b) The net thickness of the outer longitudinal bulkhead plating at the position considered:
tob ≥ Ft Dobm/I fs cm (in.)
where
Dob = 0.013 + 0.153Aob/As + 0.172 bs/B
All other parameters are as defined above.

5.7 Calculation of Local Loads (1995)

In determining the shear forces at the ends of cargo tanks, the local loads are to be calculated as shown in
the following example. The tank arrangement for this example is as shown in 5C-1-4/Figure 3. The ballast
tanks within double bottom and double side are to be considered as being empty in calculating excess
liquid head.
5.7.1 Tankers with Two Outer Longitudinal Bulkheads and a Centerline Swash or Oil-tight
Longitudinal Bulkhead (1 July 2000)
Local load Wc may be denoted by Wc(f) and Wc(a) at the fore and aft ends of the center tank,
respectively, in kN (tf, Ltf ).
Wc(f) = Wc (a) = 0.5ρ gbclc[ksHc + 0.71ks (av/g)Hc + 0.47kslcsin φ – 0.55(ρo/ρ)df +
0.2(ρo/ρ)C1] ≥ 0

but need not be taken greater than 0.5ksρ gbclcHc

where

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

ks = load factor
= 1.0 for all loads from ballast tanks
= 0.878 for ρ g of 10.05 kN/m3 (1.025 tf/m3, 0.0286 Ltf/ft3) and 1.0 for ρ g of
11.18 kN/m3 (1.14 tf/m3, 0.0318 Ltf/ft3) and above for all loads from cargo
tanks.
For cargo ρ g between 10.05 kN/m3 (1.025 tf/m3, 0.0286 Ltf/ft3) and 11.18
kN/m3 (1.14 tf/m3, 0.0318 Ltf/ft3), the factor ks may be determined by
interpolation
ρg = specific weight of the liquid, not to be taken less than 10.05 kN/m3 (1.025
tf/m3, 0.0286 Ltf/ft3)
ρog = specific weight of sea water, 10.05 kN/m3 (1.025 tf/m3, 0.0286 Ltf/ft3)
lc, bc = length and breadth, respectively, of the center tanks, in m (ft), as shown in
5C-1-4/Figure 3a
Hc = liquid head in the center tank, in m (ft)
av = vertical acceleration amidships with a wave heading angle of 0 degrees, in
m/sec2 (ft/sec2), as defined in 5C-1-3/5.7.1(c)
g = acceleration of gravity = 9.8 m/sec2 (32.2 ft/sec2)
φ = pitch amplitude in degrees, as defined in 5C-1-3/5.7.1(a)
df = draft, as defined in 3-1-1/9, in m (ft)
C1 = as defined in 3-2-1/3.5

5.7.2 Tankers with Two Outer and Two Inner Longitudinal Bulkheads (1 July 2000)
Local loads Wc1, Wc2 may be denoted by Wc1(f), Wc2(f) and, Wc1(a), Wc2(a) at the fore and aft ends
of the center tank, respectively, in kN (tf, Ltf).
k s ρ gbc1 l l2
Wc1( f ) = [hc1l1 (l2 + 1 ) + hc2 2 ]
lc 2 2

k s ρ gbc1 l2 l
Wc1(a) = [hc1 1 + hc2l2 (l1+ 2 )]
lc 2 2

k s ρ gbc 2 l l2
Wc2( f ) = [hc3l1 (l2 + 1 ) + hc4 2 ]
lc 2 2

k s ρ gbc 2 l2 l
Wc2(a) = [hc3 1 + hc4l2 (l1+ 2 )]
lc 2 2
where
ks = load factor, as defined in 5C-1-4/5.7.1

ρg = specific weight of the liquid, not to be taken less than 10.05 kN/m3
(1.025 tf/m3, 0.0286 Ltf/ft3)
lc = length of the center tank, in m (ft), as shown in 5C-1-4/Figure 3b
l1, l2 = longitudinal distances from the respective center tank ends to the
intermediate wing tank transverse bulkheads, in m (ft), as shown in
5C-1-4/Figure 3b
bc1 = breadth of the center tank, in m (ft), as shown in 5C-1-4/Figure 3b

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

bc2 = breadth of the center and wing tanks, in m (ft), as shown in 5C-1-4/Figure 3b
H1, H2 = liquid heads in the wing tanks, in m (ft), as shown in 5C-1-4/Figure 3b
hc1 = Hc − H1, but not to be taken less than zero
hc2 = Hc − H2, but not to be taken less than zero
hc3 = Hc or H1, whichever is lesser
hc4 = Hc or H2, whichever is lesser
Where adjacent tanks are loaded with cargoes of different densities, the heads are to be adjusted to
account for the difference in density. For locations away from the ends of the tanks, Rcb and Rib
may be determined using the calculated values of Wc at the locations considered.

5.9 Three Dimensional Analysis (1995)

The total shear stresses in the side shell and longitudinal bulkhead plating (net thickness) may be
calculated using a 3D structural analysis to determine the general shear distribution and local load effects
for the critical shear strength conditions among all of the anticipated loading conditions.

FIGURE 3
Center Tank Region (1995)

a Tankers with Double Hull and Centerlilne Swash or Oil-tight Longitudinal Bulkhead.
lc

bs

Hc
bc

Hc
bs

b Tankers with Four Longitudinal Bulkheads

lc
l1 l2

H2 H1

bc2 bc1 Hc

H2 H1

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

7 Double Bottom Structures

7.1 General (1995)

7.1.1 Arrangement
The depth of the double bottom and arrangement of access openings are to be in compliance with
5C-1-1/5. Centerline and side girders are to be fitted, as necessary, to provide sufficient stiffness
and strength for docking loads as well as those specified in Section 5C-1-3.
Struts connecting the bottom and inner bottom longitudinals are not to be fitted.
7.1.2 Keel Plate
The net thickness of the flat plate keel is to be not less than that required for the bottom shell
plating at that location by 5C-1-4/7.3.1 increased by 1.5 mm (0.06 in.), except where the submitted
docking plan (see 3-1-2/11) specifies all docking blocks be arranged away from the keel.
7.1.3 Bottom Shell Plating – Definition
The term “bottom shell plating” refers to the plating from the keel to the upper turn of the bilge for
0.4L amidships.
7.1.4 Bilge Longitudinals (2004)
Longitudinals around the bilge are to be graded in size from that required for the lowest side
longitudinal to that required for the bottom longitudinals. Where longitudinals are omitted in way
of the bilge, the bottom and side longitudinals are to be arranged so that the distance between the
nearest longitudinal and the turn of the bilge is not more than 0.4s (s is the spacing of bottom or
side longitudinals), as applicable (see-5C-1-4/Figure 4).

FIGURE 4

Ss

Ss
b
R. End
R
b ≤ Ss(2/5)

Sb Sb a

a ≤ Sb(2/5)
R. End

7.3 Bottom Shell and Inner Bottom Plating (1997)

The thickness of the bottom shell and inner bottom plating over the midship 0.4L is to satisfy the hull
girder section modulus requirements in 3-2-1/3.7. The buckling and ultimate strength are to be in
accordance with the requirements in 5C-1-5/5. In addition, the net thickness of the bottom shell and inner
bottom plating is to be not less than the following.

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

7.3.1 Bottom Shell Plating (1999)

The net thickness of the bottom shell plating, tn, is to be not less than t1, t2 and t3, specified as follows:
t1 = 0.73s(k1p/f1)1/2 mm (in.)

t2 = 0.73s(k2 p/f2)1/2 mm (in.)

t3 = cs(Sm fy /E)1/2 mm (in.)

where
s = spacing of bottom longitudinals, in mm (in.)
k1 = 0.342
k2 = 0.500
p = pa – puh or pb, whichever is greater, in N/cm2 (kgf/cm2, lbf/in2)

puh = 0.12γ(hlwttan φe)1/2 where lwt ≥ 0.20L

= 0 where lwt ≤ 0.15L
Linear interpolation is to be used for intermediate values of lwt.
pa and pb are nominal pressures, in N/cm2 (kgf/cm2, lbf/in2), as defined in load case “a” and “b” in
5C-1-3/Table 3 for bottom plating, respectively.
γ = specific weight of the ballast water, 1.005 N/cm2-m (0.1025 kgf/cm2-m,
0.4444 lbf/in2-ft)
h = height of double side ballast tank at vessel’s side, in m (ft)
lwt = length at tank top of double side ballast tank, in m (ft)
L = vessel length, as defined in 3-1-1/3.1, in m (ft)
φe = effective pitch amplitude, as defined in 5C-1-3/5.7.2 with Cφ = 1.0
f1 = permissible bending stress in the longitudinal direction, in N/cm2 (kgf/cm2,
lbf/in2)
= (1 − 0.70α1SMRB/SMB)Sm fy ≤ 0.40Sm fy

= (1 − 0.70α1SMRB/SMB)Sm fy ≤ (0.40 + 0.1(190 − L)/40) Sm fy for L < 190 m

α1 = Sm1fy1/Sm fy
SMRB = reference net hull girder section modulus based on the material factor of the
bottom flange of the hull girder, in cm2-m (in2-ft)
= 0.92SM
SM = required gross hull girder section modulus at the location under consideration,
in accordance with 3-2-1/3.7 and 3-2-1/5.5, based on the material factor of
the bottom flange of the hull girder, in cm2-m (in2-ft)
SMB = design (actual) net hull girder section modulus to the bottom, in cm2-m (in2-ft),
at the location under consideration
f2 = permissible bending stress in the transverse direction, in N/cm2 (kgf/cm2,
lbf/in2)
= 0.80 Sm fy

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

Sm = strength reduction factor

= 1 for Ordinary Strength Steel, as specified in 2-1-2/Table 2
= 0.95 for Grade H32, as specified in 2-1-3/Table 2
= 0.908 for Grade H36, as specified in 2-1-3/Table 2
= 0.875 for Grade H40, as specified in 2-1-3/Table 2
Sm1 = strength reduction factor for the bottom flange of the hull girder
fy = minimum specified yield point of the material, in N/cm2 (kgf/cm2, lbf/in2)
fy1 = minimum specified yield point of the bottom flange of the hull girder, in
N/cm2 (kgf/cm2, lbf/in2)
E = modulus of elasticity of the material, may be taken as 2.06 × 107 N/cm2
(2.1 × 106 kgf/cm2, 30 × 106 lbf/in2) for steel
c = 0.7N2 − 0.2, not to be less than 0.4Q1/2
N = Rb(Q/Qb)1/2

Rb = (SMRBH /SMB)1/2
SMRBH = reference net hull girder section modulus for hogging bending moment based
on the material factor of the bottom flange of the hull girder, in cm2-m (in2-ft)
= 0.92SMH
SMH = required gross hull girder section modulus, in accordance with 3-2-1/3.7.1
and 3-2-1/5.5, for hogging total bending moment at the location under
consideration, based on the material factor of the bottom flange of the hull
girder, in cm2-m (in2-ft)
Q, Qb = material conversion factor in 5C-1-4/5.1 for the bottom shell plating under
consideration and the bottom flange of the hull girder, respectively.
The net thickness, t3, may be determined based on Sm and fy of the hull girder strength material
required at the location under consideration.
In addition to the foregoing, the net thickness of the bottom shell plating, outboard of 0.3B from
the centerline of the vessel, is to be not less than that of the lowest side shell plating required by
5C-1-4/9.1 adjusted for the spacing of the longitudinals and the material factors.
7.3.2 Inner Bottom Plating (1999)
The net thickness of the inner bottom plating, tn, is to be not less than t1, t2 and t3, specified as follows:

t1 = 0.73s(k1 p/f1)1/2 mm (in.)

t2 = 0.73s(k2 p/f2)1/2 mm (in.)

t3 = cs(Sm fy /E)1/2 mm (in.)

where
s = spacing of inner bottom longitudinals, in mm (in.)
k1 = 0.342
k2 = 0.50

p = pa – puh or pb, whichever is greater, in N/cm2 (kgf/cm2, lbf/in2)

pa and pb are nominal pressures, in N/cm2 (kgf/cm2, lbf/in2), as defined in load case “a” and “b” in
5C-1-3/Table 3 for inner bottom plating, respectively.

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

puh is defined in 5C-1-4/7.3.1.

The net thickness, t3, may be determined based on Sm and fy of the hull girder strength material
required at the location under consideration.
f1 = permissible bending stress in the longitudinal direction, in N/cm2 (kgf/cm2,
lbf/in2)
= (1 − 0.52α1SMRB /SMB)Sm fy ≤ 0.57Sm fy, where SMB /SMRB is not to be taken
more than 1.4
f2 = permissible bending stress in the transverse direction, in N/cm2 (kgf/cm2, lbf/in2)
= 0.85 Sm fy

α1 = Sm1 fy1/Sm fy
Sm = strength reduction factor obtained from 5C-1-4/7.3.1 for the steel grade of
inner bottom material
Sm1 = strength reduction factor obtained from 5C-1-4/7.3.1 for the steel grade of
bottom flange material.
fy = minimum specified yield point of the inner bottom material, in N/cm2
(kgf/cm2, lbf/in2)
fy1 = minimum specified yield point of the bottom flange material, in N/cm2
(kgf/cm2, lbf/in2)
c = 0.7N 2 − 0.2, not to be less than 0.4Q1/2
N = Rb [(Q/Qb)(y/yn)] 1/2
Q = material conversion factor in 5C-1-4/5.1 for the inner bottom plating
y = vertical distance, in m (ft), measured from the inner bottom to the neutral
axis of the hull girder section
yn = vertical distance, in m (ft), measured from the bottom to the neutral axis of
the hull girder section
SMRB, SMB, Rb, Qb and E are as defined in 5C-1-4/7.3.1.
Where the breadth of the center tank exceeds 0.6B, or the wing ballast tanks are U-shaped, the net
thickness of the inner bottom plating in the center tank, outboard of 0.3B from the centerline of the
tank, is also to be not less than that of the adjacent strake on the outer longitudinal bulkhead (inner
skin) required by 5C-1-4/13.1, adjusted for the spacing of the longitudinals and the material factors.

7.5 Bottom and Inner Bottom Longitudinals (1 July 2005)

The net section modulus of each bottom or inner bottom longitudinal, in association with the effective
plating to which it is attached, is to be not less than obtained from the following equations:
SM = M / fb cm3 (in3)
where
M = 1000 psl2/k N-cm (kgf-cm, lbf-in.)
k = 12 (12, 83.33)
s = spacing of longitudinals, in mm (in.)
l = span of the longitudinal between effective supports, as shown in 5C-1-4/Figure 5, in
m (ft)
p = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), as specified in 5C-1-4/7.3.1 and
5C-1-4/7.3.2 for bottom and inner bottom longitudinals, respectively

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

fb = permissible bending stresses, in N/cm2 (kgf/cm2, lbf/in2)

= (1.0 − 0.65α1SMRB/SMB)Sm fy ≤ 0.55Sm fy for bottom longitudinals

= (1.0 − 0.50α1SMRB/SMB)Sm fy ≤ 0.65Sm fy for inner bottom longitudinals

α1 = Sm1 fy1/Sm fy
Sm = strength reduction factor, as defined in 5C-1-4/7.3.1, for the material of longitudinals
considered
Sm1 = strength reduction factor, as defined in 5C-1-4/7.3.1, for the bottom flange material
fy = minimum specified yield point for the material of longitudinals considered, in N/cm2
(kgf/cm2, lbf/in2)
fy1 = minimum specified yield point of the bottom flange material, in N/cm2 (kgf/cm2, lbf/in2)
SMRB and SMB are as defined in 5C-1-4/7.3.1.
The net section modulus of the bottom longitudinals, outboard of 0.3B from the centerline of the vessel, is
also to be not less than that of the lowest side longitudinal required by 5C-1-4/9.5, adjusted for the span
and spacing of the longitudinals and the material factors.
Where the breadth of center tank exceeds 0.6B, or the wing ballast tanks are U-shaped, the net section
modulus of the inner bottom longitudinals in the center tank, outboard of 0.3B from the centerline of the
tank, is also to be not less than that of the lowest outer longitudinal bulkhead longitudinal required by
5C-1-4/13.5, adjusted for the span and spacing of the longitudinals and the material factors.
In determining compliance with the foregoing, an effective breadth, be, of attached plating is to be used in
calculation of the section modulus of the design longitudinal. be is to be obtained from line a) of
5C-1-4/Figure 6.

7.7 Bottom Girders/Floors (1997)

The minimum scantlings for bottom girders/floors are to be determined from 5C-1-4/7.7.1, 5C-1-4/7.7.2,
5C-1-4/7.7.3 and 5C-1-4/7.7.4, as follows:
7.7.1 Bottom Centerline Girder (1999)
The net thickness of the centerline girder amidships, where no centerline bulkhead is fitted, is to
be not less than t1 and t2, as defined below:
t1 = (0.045L + 4.5)R mm
= (0.00054L + 0.177)R in.
t2 = 10F1/(db fs) mm
= F1/(db fs) in.
The net thickness, t3, may be determined based on Sm and fy of the hull girder strength material
required at the location under consideration.
t3 = cs(Sm fy /E)1/2 mm (in.)
where F1 is the maximum shear force in the center girder, as obtained from the equations given
below (see also 5C-1-4/1.3). Alternatively, F1 may be determined from finite element analyses, as
specified in 5C-1-5/9, with the combined load cases in 5C-1-5/9.9. However, in no case should F1
be taken less than 85% of that determined from the equations below:
F1 = 1000kα1γ n1n2 plss1 N (kgf, lbf), for λ ≤ 1.5

F1 = 414kγ n1n2 pbs s1 N (kgf, lbf), for λ > 1.5

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

where
k = 1.0 (1.0, 2.24)
α1 = 0.606 − 0.22λ

λ = ls/bs

γ = 2x/(ls − s3), ≤ 1.0

n1 = 0.0374(s1/s3)2 − 0.326(s1/s3) + 1.289

n2 = 1.3 − (s3/12) for SI or MKS Units

= 1.3 − (s3/39.37) for U.S. Units

ls = unsupported length of the double bottom structures under consideration, in m
(ft), as shown in 5C-1-4/Figure 7
bs = unsupported width of the double bottom structures under consideration, in m
(ft), as shown in 5C-1-4/Figure 7.
s1 = sum of one-half of girder spacing on each side of the center girder, in m (ft)
s3 = spacing of floors, in m (ft)
x = longitudinal distance from the mid-span of unsupported length (ls) of the
double bottom to the section of the girder under consideration, in m (ft).
p = nominal pressure, in kN/m2 (tf/m2, Ltf/ft2), as specified in 5C-1-3/Table 3
db = depth of double bottom, in cm (in.)

fs = permissible shear stresses, in N/cm2 (kgf/cm2, lbf/in2)

= 0.45 Sm fy

c = 0.7N2 − 0.2, not to be less than 0.4Q1/2 but need not be greater than
0.45(Q/Qb)1/2

N = Rb (Q/Qb)1/2
Q = material conversion factor in 5C-1-4/5.1 for the bottom girder
s = spacing of longitudinal stiffeners on the girder, in mm (in.)
R = 1.0 for ordinary mild steel
= fym/Sm fyh for higher strength material
fym = specified minimum yield point for ordinary strength steel, in N/cm2 (kgf/cm2,
lbf/in2)
fyh = specified minimum yield point for higher tensile steel, in N/cm2 (kgf/cm2,
lbf/in2)
L = length of vessel, in m (ft), as defined in 3-1-1/3.1.
Sm, E, Rb, Qb and fy are as defined in 5C-1-4/7.3.1.

7.7.2 Bottom Side Girder (1999)

The net thickness of the bottom side girders is to be not less than t1 and t2, as defined below:
t1 = (0.026L + 4.5)R mm
= (0.00031L + 0.177)R in.

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

t2 = 10 F2/(db fs) mm
= F2/(db fs) in.
The net thickness, t3, may be determined based on Sm and fy of the hull girder strength material
required at the location under consideration.
t3 = cs(Sm fy/E)1/2 mm (in.)
where F2 is the maximum shear force in the side girders under consideration, as obtained from the
equations given below (see also 5C-1-4/1.3). Alternatively, F2 may be determined from finite
element analyses, as specified in 5C-1-5/9, with the combined load cases in 5C-1-5/9.9. However,
in no case should F2 be taken less than 85% of that determined from the equations below:
F2 = 1000 kα2β1γ n3n4 plss2 N (kgf, lbf), for λ ≤ 1.5

F2 = 285kβ1γ n3n4 pbss2 N (kgf, lbf), for λ > 1.5

where
k = 1.0 (1.0, 2.24)
α2 = 0.445 − 0.17λ

β1 = 1.25 − (2z1/bs) for tankers with inner skin only [5C-1-4/Figure 7(d)]
= 1.0 for all other tankers
n3 = 1.072 − 0.0715(s2/s3)

n4 = 1.2 − (s3/18) for SI or MKS Units

= 1.2 − (s3/59.1) for U.S. Units

s2 = sum of one-half of girder spacings on both sides of the side girders, in m (ft)
z1 = transverse distance from the centerline of the unsupported width bs of the
double bottom to the girder under consideration, in m (ft)
c = 0.7N2 − 0.2, not to be less than 0.4Q1/2, but need not be greater than
0.45(Q/Qb)1/2
N = Rb (Q/Qb)1/2
Q = material conversion factor in 5C-1-4/5.1 for the bottom girder
s = spacing of longitudinal stiffeners on the girder, in mm (in.)
γ, ls, bs, λ, s3, p, db, fs, L, R, Sm and fy are as defined above.

7.7.3 Floors (1997)

The net thickness of the floors is to be not less than t1 and t2, as specified below:
t1 = (0.026L + 4.50)R mm
= (0.00031L + 0.177)R in.
t2 = 10F3/(db fs) mm
= F3/(db fs) in.
where F3 is the maximum shear force in the floors under consideration, as obtained from the
equation given below (see also 5C-1-4/1.3). Alternatively, F3 may be determined from finite
element analyses, as specified in 5C-1-5/9, with the combined load cases in 5C-1-5/9.9. However,
in no case should F3 be taken less than 85% of that determined from the equation below.

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

F3 = 1000kα3β2 pbs s3 N (kgf, lbf)

where
k = 1.0 (1.0, 2.24)
α3 as shown in 5C-1-4/Figure 7.
ρ0 = η(0.66 − 0.08η), for η ≤ 2.0

= 1.0, for η > 2.0, or for structures without longitudinal girders

β2 = 1.05(2z2/bs) ≤ 1.0
2
for tankers with inner skin only [5C-1-4/Figure 7(d)]
= 2z2/bs for all other tankers

η = (ls/bs)(s0/s3)1/4
s0 = average spacing of girders, in m (ft)
z2 = transverse distance from the centerline of the unsupported width bs of the
double bottom to the section of the floor under consideration, in m (ft)
fs = 0.45 Sm fy in N/cm2 (kgf/cm2, lbf/in2)

ls, bs, s3, R, p, db, L, Sm and fy are as defined above.

7.7.4 Bottom Girders under Longitudinal Bulkhead (1 July 2005)

The net thickness of the bottom centerline and side girders under longitudinal bulkheads is to be
not less than t1 and t2, as defined below:
t1 = (0.045L + 3.5)R mm
= (0.00054L + 0.138)R in.
The net thickness, t2, may be determined based on Sm and fy of the hull girder strength material
required at the location under consideration.
t2 = cs(Sm fy/E)1/2 mm (in.)
where
c = 0.7N 2 − 0.2, not to be less than 0.4Q1/2
N = Rb (Q/Qb)1/2
Q = material conversion factor in 5C-1-4/5.1 for the bottom girder
s = spacing of longitudinal stiffeners on the girder, in mm (in.)
L, R, Sm and fy are as defined above.
E, Rb and Qb are as defined in 5C-1-4/7.3.1.

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

FIGURE 5
Unsupported Span of Longitudinal (1995)

Trans Trans
a) Supported by transverses

F.B. F.B.

Trans Trans
b) Supported by transverses
and flat bar stiffeners

F.B. F.B.

d/2

Trans Trans

c) Supported by transverses,
flat bar stiffeners
and brackets

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

FIGURE 6
Effective Breadth of Plating be (1995)

lw
l

Longitudinal

Mx
M

c l c lo
For bending For bending
at ends at midspan s = spacing of longitudinals

a) For bending at midspan

clo/s 1.5 2 2.5 3 3.5 4 4.5 and greater
be/s 0.58 0.73 0.83 0.90 0.95 0.98 1.0

b) For bending at ends [be/s = (0.124cl/s – 0.062)1/2]

cl/s 1 1.5 2 2.5 3 3.5 4.0

be/s 0.25 0.35 0.43 0.5 0.55 0.6 0.67

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

FIGURE 7
Definitions of α3, ls and bs (1995)

ls

T. Bhd T. Bhd
(a)

bs
bs bs

α3 = 0.35 po α3 = 0.55 po
α3 = 0.5 po α3 = 0.65 po L
C (inboard)
(outboard)
L
C (outboard)
α3 = 0.5 po
(inboard)

(b) (c)

bs

α3 = 0.5 po
(d) L
C

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

9 Side Shell and Deck – Plating and Longitudinals

9.1 Side Shell Plating (1 July 2005)

The net thickness of the side shell plating, in addition to compliance with 5C-1-4/5.3, is to be not less than
t1, t2 and t3, as specified below for the midship 0.4L:

t1 = 0.73s(k1p/f1)1/2 mm (in.)

t2 = 0.73s(k2 p/f2)1/2 mm (in.)

t3 = cs(Sm fy /E)1/2 mm (in.)
where
s = spacing of side longitudinals, in mm (in.)
k1 = 0.342
k2 = 0.50

p = pa – puo or pb, whichever is greater, in N/cm2 (kgf/cm2, lbf/in2)

puo = 0.24γ(hlwtbwt tan φe tan θe)1/3 where lwt ≥ 0.20L

= 0 where lwt ≤ 0.15L
Linear interpolation is to be used for intermediate values of lwt.
pa and pb are nominal pressures at the lower edge of each plate strake, in N/cm2 (kgf/cm2, lbf/in2), as
defined in load case “a” and “b” 5C-1-3/Table 3 for side shell plating. t1 and t2 as calculated for each plate
need not to be taken in excess of those calculated at the upper turn of the bilge. Where the wing ballast
tanks are U-shaped, the nominal pressure may be taken at the lower edge of each plate, but is not to be less
than that calculated at upper turn of bilge for J-shaped ballast tanks.
bwt = breadth at tank top of double side ballast tank, in m (ft)

φe = effective pitch amplitude, as defined in 5C-1-3/5.7.2, with Cφ = 0.7

θe = effective roll amplitude, as defined in 5C-1-3/5.7.2, with Cθ = 0.7

L is vessel length, as defined in 3-1-1/3.1, in m (ft).
γ, h and lwt are also defined in 5C-1-4-/7.3.1.
The net thickness, t3, may be determined based on Sm and fy of the hull girder strength material required at
the location under consideration.
f1 = permissible bending stress, in the longitudinal direction, in N/cm2 (kgf/cm2, lbf/in2)

= [0.86 − 0.50α1(SMRB/SMB)(y/yb)]Sm fy

≤ 0.43 Sm fy, for L ≥ 190 m (623 ft), below neutral axis

≤ [0.43 + 0.17(190 − L)/40]Sm fy, for L < 190 m (623 ft), below neutral axis.
SMB/SMRB is not to be taken more than 1.4.

= 0.43 Sm fy, for L ≥ 190 m (623 ft), above neutral axis

= [0.43 + 0.17 (190 − L)/40]Sm fy for L < 190 m (623 ft), above neutral axis

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

f2 = permissible bending stress in the vertical direction, in N/cm2 (kgf/cm2, lbf/in2)

= 0.80 Sm fy

α1 = Sm1 fy1/Sm fy
Sm = strength reduction factor obtained from 5C-1-4/7.3.1 for the steel grade of side shell
plating material
Sm1 = strength reduction factor obtained from 5C-1-4/7.3.1 for the steel grade of bottom
flange material
fy = minimum specified yield point of the side shell material, in N/cm2 (kgf/cm2, lbf/in2)
fy1 = minimum specified yield point of the bottom flange material, in N/cm2 (kgf/cm2,
lbf/in2)
yb = vertical distance, in m (ft), measured from the upper turn of bilge to the neutral axis
of the section
c = 0.7N2 − 0.2, not to be less than 0.4Q 1/2
N = Rd (Q/Qd)1/2 for the sheer strake

= Rd [(Q/Qd)(y/yn)]1/2 for other locations above neutral axis

= Rb [(Q/Qb)(y/yn)]1/2 for locations below neutral axis

Rd = (SMRDS/SMD)1/2
y = vertical distance, in m (ft), measured from the neutral axis of the hull girder transverse
section to the lower edge (upper edge) of the side shell strake, when the strake under
consideration is below (above) the neutral axis for N.
= vertical distance, in m (ft), measured from the neutral axis of the hull girder transverse
section to the lower edge of the side shell strake under consideration for f1.
SMRDS = reference net hull girder section modulus for sagging bending moment, based on the
material factor of the deck flange of the hull girder, in cm2-m (in2-ft)
= 0.92SMS
SMS = required gross hull girder section modulus, in accordance with 3-2-1/3.7.1 and 3-2-1/5.5,
for sagging total bending moment at the location under consideration, based on the
material factor of the deck flange of the hull girder, in cm2-m (in2-ft)
Q, Qd = material conversion factor in 5C-1-4/5.1 for the side shell plating under consideration
and the deck flange of the hull girder, respectively.
yn = vertical distance, in m (ft), measured from the bottom (deck) to the neutral axis of the
section, when the strake under consideration is below (above) the neutral axis.
SMRB, SMB, Rb, Qb and E are as defined in 5C-1-4/7.3.1. SMD is as defined in 5C-1-4/9.5.
However, for plate panels above the neutral axis, t3 need not be taken greater than the value that satisfies
the following buckling requirement.
Mt
≤ fc
SM R

fc = fE for fE ≤ Pr fy

⎡ fy ⎤
fc = fy ⎢1 − Pr (1 − Pr ) ⎥ for fE > Pr fy
⎣ fE ⎦

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

where
2
c1π 2 E ⎛ t 3 ⎞
⎜ ⎟
fE =
(
3 1 −ν 2 ⎝ s ⎠)
c1 = 1.0 for plate panels between flat bars or bulb plates
= 1.1 for plate panels between angles or tee stiffeners
Pr = proportional linear elastic limit of the structure, may be taken as 0.6 for steel
ν = Poisson’s ratio, may be taken as 0.3 for steel
Mt = total sagging bending moment
SMR = section modulus at the center of the plate panel under consideration.
The minimum width of the sheer strake for the midship 0.4L is to be in accordance with 3-2-2/3.11.
The thickness of the sheer strake is to be increased 25% in way of breaks of superstructures, but this
increase need not exceed 6.5 mm (0.26 in.).
In addition, the net thickness of the side shell plating is not to be taken less than t4 obtained from the
following equation:
t4 = 90(s/1000 + 0.7) [B d /(Sm fy)2]1/4 +0.5 mm
where
s = spacing of side longitudinal stiffeners, in mm
B = breadth of vessel, as defined in 3-1-1/5, in m
d = molded draft, as defined in 3-1-1/9, in m
All other parameters are as defined above.
The net thickness, t4, is to be applied to the following extent of the side shell plating:

• Longitudinal extent. Between a section aft of amidships where the breadth at the waterline exceed
0.9B, and a section forward of amidships where the breadth at the waterline exceeds 0.6B.
• Vertical extent. Between 300 mm below the lowest ballast waterline to 0.25d or 2.2 m, whichever is
greater, above the summer load line.

9.3 Deck Plating (1 July 2005)

The thickness of the strength deck plating is to be not less than that needed to meet the hull girder section
modulus requirement in 3-2-1/3.7. The buckling and ultimate strength are to be in accordance with the
requirements in 5C-1-5/5. In addition, the net thickness of deck plating is to be not less than t1, t2 and t3, as
specified below for the midship 0.4L:
t1 = 0.73s(k1p/f1)1/2 mm (in.)
1/2
t2 = 0.73s(k2 p/f2) mm (in.)
1/2
t3 = cs(Sm fy/E) mm (in.)
where
s = spacing of deck longitudinals, in mm (in.)
k1 = 0.342
k2 = 0.50
p = pn in cargo tank, in N/cm2 (kgf/cm2, lbf/in2)
= pn – puh in ballast tank, in N/cm2 (kgf/cm2, lbf/in2)
In no case is p to be taken less than 2.06 N/cm2 (0.21 kgf/cm2, 2.987 lbf/in2).

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

pn is nominal pressure, in N/cm2 (kgf/cm2 lbf/in2), as defined in 5C-1-3/Table 3 for deck plating.
puh is defined in 5C-1-4/7.3.1.
The net thickness, t3, may be determined based on Sm and fy of the hull girder strength material required at
the location under consideration.
f1 = permissible bending stress in the longitudinal direction, in N/cm2 (kgf/cm2, lbf/in2)
= 0.15 Sm fy

f2 = permissible bending stress in the transverse direction, in N/cm2 (kgf/cm2, lbf/in2)

= 0.80 Sm fy
c = 0.5 (0.6 + 0.0015L) for SI or MKS Units
= 0.5 (0.6 + 0.00046L) for U.S. Units
c is not to be taken less than (0.7N − 0.2) for vessels having length less than 267 m (876 ft)
2

L = length of vessel, in m (ft), as defined in 3-1-1/3.1

N = Rd (Q/Qd)1/2
Rd = (SMRDS/SMD)1/2
Q = material conversion factor in 5C-1-4/5.1 for the deck plating
Sm, fy and E are as defined in 5C-1-4/7.3.1.
SMRDS and Qd are as defined in 5C-1-4/9.1.
SMD is as defined in 5C-1-4/9.5.
t3 need not be taken greater than the value that satisfies the following buckling requirement.

Mt
≤ fc
SM D

fc = fE for fE ≤ Pr fy

⎡ fy ⎤
fc = fy ⎢1 − Pr (1 − Pr ) ⎥ for fE > Pr fy
⎣ fE ⎦

where
2
c1c 2 π 2 E ⎛ t 3 ⎞
⎜⎜ ⎟⎟
fE =
( )
3 1 −ν 2 ⎝ s ⎠
c1 = 1.0 for plate panels between flat bars or bulb plates
= 1.1 for plate panels between angles or tee stiffeners
c2 = 1.0 for plate panels within the cargo tank space
= 1.1 for plate panels within the side ballast tank space
Pr = proportional linear elastic limit of the structure, may be taken as 0.6 for steel

ν = Poisson’s ratio, may be taken as 0.3 for steel

Mt = total sagging bending moment

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

The thickness of the stringer plate is to be increased 25% in way of breaks of superstructures, but this
increase need not exceed 6.5 mm (0.25 in.). The required deck area is to be maintained throughout the
midship 0.4L of the vessel or beyond the end of a superstructure at or near the midship 0.4L point. From
these locations to the ends of the vessel, the deck area may be gradually reduced in accordance with
3-2-1/11.3. Where bending moment envelope curves are used to determine the required hull girder section
modulus, the foregoing requirements for strength deck area may be modified in accordance with
3-2-1/11.3. Where so modified, the strength deck area is to be maintained a suitable distance from
superstructure breaks and is to be extended into the superstructure to provide adequate structural continuity.
The structural drawings for major on-deck outfitting members are to be submitted. Special attention is to
be paid to the attachments of deck fittings to deck plate so that harmful stress concentration or any failure
due to cyclic loads can be avoided. If any structural reinforcement is not allowed due to a specific
structural arrangement, the fatigue strength calculations of the attachment may be required for review.

9.5 Deck and Side Longitudinals (1 July 2005)

The net section modulus of each individual side or deck longitudinal, in association with the effective
plating to which it is attached, is to be not less than obtained from the following equation:
SM = M/fb cm3 (in3)

M = 1000psl2/k N-cm (kgf-cm, lbf-in)

where
k = 12 (12, 83.33)
p = pai – puo or pb, whichever is greater, for side longitudinals, in N/cm2 (kgf/cm2, lbf/in2)

= pn for deck longitudinals in cargo tank, in N/cm2 (kgf/cm2, lbf/in2)

= pn – puh for deck longitudinals in ballast tank, N/cm2 (kgf/cm2, lbf/in2)

In no case is p to be taken less than 2.06 N/cm2 (0.21 kgf/cm2, 2.987 lbf/in2).
pa and pb are nominal pressures, in N/cm2 (kgf/cm2, lbf/in2), as defined in load case “a” and “b”, at the side
longitudinal considered, in 5C-1-3/Table 3 for side longitudinals, respectively.
pn is nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), as defined in 5C-1-3/Table 3 for deck longitudinals.
puoand puh are defined in 5C-1-4/9.1 and 5C-1-4/7.3.1, respectively.

s and l are as defined in 5C-1-4/7.5.

fb = permissible bending stresses, in N/cm2 (kgf/cm2, lbf/in2)

= (1.0 − 0.60α2SMRD/SMD)Sm fy for deck longitudinals

= 1.0[0.86 − 0.52α1(SMRB/SMB)(y/yn)] Sm fy ≤ 0.75Sm fy

for side longitudinals below neutral axis
= 2.0[0.86 − 0.52α2(SMRD/SMD)(y/yn)] Sm fy ≤ 0.75Sm fy
for side longitudinals above neutral axis
α2 = Sm2 fy2/Sm fy

Sm, fy and α1 are as defined in 5C-1-4/7.5.

Sm2 = strength reduction factor, as obtained from 5C-1-4/7.3.1, for the steel grade of top
flange material of the hull girder.
fy2 = minimum specified yield point of the top flange material of the hull girder, in N/cm2
(kgf/cm2, lbf/in2)

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

SMRD = reference net hull girder section modulus based on the material factor of the top
flange of the hull girder, in cm2-m (in2-ft)
= 0.92 SM
SM = required gross hull girder section modulus at the location under consideration, in
accordance with 3-2-1/3.7 and 3-2-1/5.5, based on the material factor of the top
flange of the hull girder, in cm2-m (in2-ft)
SMD = design (actual) net hull girder section modulus at the deck, in cm2-m (in2-ft), at the
location under consideration
SMRB and SMB are as defined in 5C-1-4/7.3.1.
y = vertical distance in m (ft) measured from the neutral axis of the section to the
longitudinal under consideration at its connection to the associated plate
yn = vertical distance, in m (ft), measured from the deck (bottom) to the neutral axis of the
section, when the longitudinal under consideration is above (below) the neutral axis.
Where the wing ballast tanks are U-shaped, the net section modulus of deck longitudinals in the wing
ballast tanks is to be not less than that of the uppermost side longitudinal, adjusted for the span and spacing
of the longitudinal and the material factors.
Where the breadth of center tank exceeds 0.6B, the net section modulus of deck longitudinals in the center
tank, located outboard of 0.3B from the centerline of the tank, is also to be not less than that of the
uppermost boundary longitudinal bulkhead longitudinal required by 5C-1-4/13.5 of this Section, adjusted
for the span and spacing of the longitudinal and the material factors.
In determining compliance with the foregoing, an effective breadth, be, of attached plating is to be used in
the calculation of the section modulus of the design longitudinal. be is to be obtained from line a) of
5C-1-4/Figure 6.
The net moment of inertia about the neutral axis of deck longitudinals and side longitudinals within the
region of 0.1D from the deck, in association with the effective plating (bwLtn), is to be not less than
obtained from the following equation:
io = kAel2fy/E cm4 (in4)
where
k = 1220 (1220, 17.57)
Ae = net sectional area of the longitudinal with the associated effective plating bwL tn, in
cm2 (in2)
bwL = cs

c = 2.25/β − 1.25β2 for β ≥ 1.25

= 1.0 for β < 1.25
β = (fy /E)1/2 s/tn
tn = net thickness of the plate, in mm (in.)
D = depth of vessel, in m (ft), as defined in 3-1-1/7.
l, s and fy are as defined in 5C-1-4/7.5.
E is as defined in 5C-1-4/7.3.1.

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

11 Side Shell and Deck – Main Supporting Members (1995)

11.1 General (1997)

The main supporting members, such as transverses and girders, are to be arranged and designed with
sufficient stiffness to provide support to the vessel’s hull structures. In general, the deck transverses, side
transverses and bottom floors are to be arranged in one plane to form continuous transverse rings. Deck
girders, where fitted, are to extend throughout the cargo tank spaces and are to be effectively supported at
the transverse bulkheads.
Generous transitions are to be provided at the intersections of main supporting members to provide smooth
transmission of loads and to minimize the stress concentrations. Abrupt changes in sectional properties and
sharp re-entrant corners are to be avoided. It is recommended that the intersection of the inner skin and
inner bottom be accomplished by using generous sloping or large radiused bulkheads. Stool structures,
where fitted, are to have sloping bulkheads on both sides.
The net section modulus and sectional area of the main supporting members required by Part 5C, Chapter 1
apply to those portions of the member clear of the end brackets. They are considered as the requirements of
initial scantlings for deck transverses, side transverses, vertical webs on longitudinal bulkheads and
horizontal girders and vertical webs on transverse bulkheads, and may be reduced, provided that the
strength of the resultant design is verified with the subsequent total strength assessment in Section 5C-1-5.
However, in no case should they be taken less than 85% of those determined from 5C-1-4/11 or 5C-1-4/15.
(See also 5C-1-5/9.1). The structural properties of the main supporting members and end brackets are to
comply with the failure criteria specified in 5C-1-5/3.
The section modulus of the main supporting members is to be determined in association with the effective
plating to which they are attached, as specified in 3-1-2/13.
(1 July 2000) In calculation of the nominal pressure, ρ g of the liquid cargoes is not to be taken less than
0.1025 kgf/cm2-m (0.4444 lbf/in2-ft) for main supporting members.

11.3 Deck Transverses

11.3.1 Section Modulus of Deck Transverses (1 July 2005)
The net section modulus of deck transverses is to be not less than obtained from the following
equation (see also 5C-1-4/1.3):
SM = M/fb cm3 (in3)
For deck transverses in wing cargo tanks (See 5C-1-4/Figure 2A-a, b, c, d, e, and f):

M = k(10,000 c1ϕ ps l 2t + βs Ms) ≥ Mo N-cm (kgf-cm, lbf-in)

For deck transverses in center cargo tanks (see 5C-1-4/Figure 2A-d, e and f)

M = k(10,000 c1ϕ ps l 2t + βb Mb) ≥ Mo N-cm (kgf-cm, lbf-in)

where

Ms = 10,000c2 ps s l 2s

Mb = 10,000c2 pb s l 2b

Mo = 10,000kc3 ps l 2t
k = 1.0 (1.0, 0.269)
p = nominal pressure, in kN/m2 (tf/m2, Ltf/ft2), at the mid span of the deck
transverse under consideration, as specified in 5C-1-3/Table 3, item 16. In
no case is p to be taken less than 2.06 N/cm2 (0.21 kgf/cm2, 2.987 lbf/in2).
ps = corresponding nominal pressure, in kN/m2 (tf/m2, Ltf/ft2), at the mid-span of
the side transverse (5C-1-3/Table 3, item 12)

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

pb = corresponding nominal pressure, in kN/m2 (tf/m2, Ltf/ft2), at the mid-span of

the vertical web on longitudinal bulkhead (5C-1-3/Table 3, item 13)
c1 for tanks without deck girders:
= 0.30 for 5C-1-4/Figure 2A-c with non-tight centerline bulkhead
= 0.42 for all other cases
c1 for tanks with deck girders:

= 0.30α2 for 5C-1-4/Figure 2A-b with a non-tight centerline bulkhead, 0.05

min. and 0.30 max.
= 0.42α2 for 5C-1-4/Figure 2A-a or 5C-1-4/Figure 2A-b with an oil-tight
centerline bulkhead, 0.05 min. and 0.42 max.
α = (lg/lt)[(sg/s)(It /Ig)]1/4

lg = span of the deck girder, in m (ft), as indicated in 5C-1-4/Figure 2B-c

lt = span of the deck transverse, in m (ft), as indicated in 5C-1-4/Figure 2A, but
is not to be taken as less than 60% of the breadth of the tank, except for tankers
with a non-tight centerline bulkhead (5C-1-4/Figure 2A-b), for which the
span is not to be taken as less than 30% of the breadth of the tank.
Ig, It = moments of inertia, in cm4 (in4), of the deck girder and deck transverse, clear
of the brackets, respectively
sg = spacing of the deck girder, in m (ft)
s = spacing of the deck transverses, in m (ft)
When calculating α, if more than one deck girder is fitted, average values of sg, lg and Ig are to be
used when the girders are not identical.
ϕ = 1 − [5(ha/αlt)], for cargo tanks with deck girders, 0.6 minimum

= 1 − 5(ha/lt), for cargo tanks without deck girders, 0.6 minimum

ha = distance, in m (ft), from the end of the span to the toe of the end bracket of
the deck transverse, as indicated in 5C-1-4/Figure 8
βs = 0.9[(ls /lt)(It /Is)], 0.10 min. and 0.65 max.

βb = 0.9[(lb /lt)(It /Ib)], 0.10 min. and 0.50 max.

ls and lb = spans, in m (ft), of side transverse and vertical web on longitudinal bulkhead,
respectively, as indicated in 5C-1-4/Figure 2A. Where a cross tie is fitted and
is located at a distance greater than 0.7ls or 0.7lb from the deck transverse,
the effective span of the side transverse or the vertical web may be taken as
that measured from the deck transverse to the cross tie and all coefficients
determined as if there were no cross tie.
Is and Ib = moments of inertia, in cm4 (in4), clear of the brackets, of side transverse and
vertical web on longitudinal bulkhead, respectively
fb = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.70 Sm fy
Sm and fy, as defined in 5C-1-4/7.3.1.
c2 is given in 5C-1-4/Table 1.

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

c3 = 2.0c1 for tankers with oil-tight longitudinal bulkheads and without deck
girders (5C-1-4/Figure 2A-c, d, e and f)
= 1.6c1 for tankers with non-tight centerline longitudinal bulkhead and without
deck girders (5C-1-4/Figure 2A-c)
= 1.1c1 for cargo tanks with deck girders
The section modulus of the deck transverse in the wing cargo tank is to be not less than that of the
deck transverse in the center tank.
11.3.2 Sectional Area of Deck Transverses
The net sectional area of the web portion of deck transverses is to be not less than obtained from
the following equation:
A = F/fs cm2 (in2)

F = 1000k[c1ps(0.50l − he) + c2DBc s] N (kgf, lbf)

where
k = 1.0 (1.0, 2.24)
c2 = 0.05 for wing cargo tanks of tankers with four longitudinal bulkheads
(5C-1-4/Figure 2A-d, e and f)
= 0 for other tanks (5C-1-4/Figure 2A-a, b, c, d, e and f)
c1 for tanks with deck girders:

= 0.90α1/2 for 5C-1-4/Figure 2A-a without longitudinal bulkhead and for

5C-1-4/Figure 2A-b with an oil-tight centerline bulkhead, 0.50 min. and
1.0 max.
= 0.60α1/2 for 5C-1-4/Figure 2A-b with a non-tight centerline bulkhead,
0.45 min. and 0.85 max.
c1 for tanks without deck girders:
= 1.10 for 5C-1-4/Figure 2A-c, with a nontight centerline longitudinal
bulkhead
= 1.30 for all other cases (5C-1-4/Figure 2A-c, d, e and f)
l = span of the deck transverse, in m (ft), as indicated in 5C-1-4/Figure 2A
he = length of the bracket, in m (ft), as indicated in 5C-1-4/Figure 2A-c and
5C-1-4/Figure 2A-d and 5C-1-4/Figure 8
D = depth of the vessel, in m (ft), as defined in 3-1-1/7
Bc = breadth of the center tank, in m (ft)

p, s and α, as defined in 5C-1-4/11.3.1

fs = permissible shear stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.45 Sm fy
Sm and fy, as defined in 5C-1-4/7.3.1.

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

11.5 Deck Girders

11.5.1 Section Modulus of Deck Girders (1 July 2005)
The net section modulus of deck girders is to be not less than obtained from the following equation
(see also 5C-1-4/1.3):
SM = M /fb cm3 (in3)
M equals M1 or M2, whichever is greater, as given below:

M1 = 4200kpsg l 2g N-cm (kgf-cm, lbf-in)

M2 = k(3000ϕpsg l 2g + 0.15Mb) N-cm (kgf-cm, lbf-in)

Mb = 10,000pst sg l 2st N-cm (kgf-cm, lbf-in)

where
k = 1.0 (1.0, 0.269)
lg = span, in m (ft), of the deck girder, as indicated in 5C-1-4/Figure 2B-c
lst = span, in m (ft), of the vertical web on transverse bulkhead, as indicated in
5C-1-4/Figure 2B-c
sg = spacing, in m (ft), of the deck girder considered, as indicated in
5C-1-4/Figure 2A
ϕ = 1 − 5(ha/lg), 0.6 min.
ha = distance, in m (ft), from the end of the span to the toe of the end bracket of
the deck girder, as indicated in 5C-1-4/Figure 2B-c and 5C-1-4/Figure 8
p = nominal pressure, in kN/m2 (tf/m2, Ltf/ft2), as specified in 5C-1-3/Table 3,
item 17 for the girder considered. Where three or more deck girders are fitted
in the cargo tank, p is to be not less than its value determined for the
outermost girder clear of the end bracket of the deck transverse. In no case is
p to be taken less than 2.06 N/cm2 (0.21 kgf/cm2, 2.987 lbf/in2).
pst = corresponding nominal pressure, in kN/m2 (tf/m2, Ltf/ft2), at the mid-span of
the vertical web on the forward transverse bulkhead of cargo tank under
consideration (5C-1-3/Table 3, item 17)
fb = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.45 Sm fy
= (1.0 − 0.55α2SMRD/SMD)Sm fy ≤ 0.52Sm fy for L < 190 m
Sm and fy, as defined in 5C-1-4/7.3.1.

11.5.2 Sectional Area of Deck Girder

The net sectional area of the web portion of deck girders is to be not less than obtained from the
following equation:
A = F /fs cm2 (in2)

F = 1000kcpsg(0.5l − he) N (kgf, lbf)

where
k = 1.0 (1.0, 2.24)
c = 0.55 for one or two girders in the tank
= 0.67 for three or more girders in the tank

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

l = span of the deck girder, in m (ft), as indicated in 5C-1-4/Figure 2B-c

he = length of the bracket, in m (ft), as indicated in 5C-1-4/Figure 2B-c and
5C-1-4/Figure 8.
p and sg are defined in 5C-1-4/11.5.1.
fs = permissible shear stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.30 Sm fy
Sm and fy, as defined in 5C-1-4/7.3.1.

11.7 Web Sectional Area of Side Transverses

The net sectional area of the web portion of side transverses is to be not less than obtained from the
following equation:
A = F /fs cm2 (in2)
The shear force F, in N (kgf, lbf), for the side transverse can be obtained from the following equations (see
also 5C-1-4/1.3):
F = 1000ks[KU l(PU + PL) − hUPU] for upper part of transverse
F = 1000ks[KL l(PU + PL) − hLPL] or 350ksKL l(PU + PL) whichever is greater
for lower part of transverse
In no case is the shear force for the lower part of the transverse to be less than 120% of that for the upper
part of the transverse.
where
k = 1.0 (1.0, 2.24)
l = span, in m (ft), of the side transverse, as indicated in 5C-1-4/Figure 2B-a. Where one
cross tie is fitted in the wing tank and is located at a distance of more than 0.7l from
the deck transverse, the effective span of the side transverse may be measured from
the deck transverse to the cross tie and all coefficients determined as if there were no
cross tie.
s = spacing, in m (ft), of the side transverses
PU = nominal pressure, p, in kN/m2 (tf/m2, Ltf/ft2), at the mid-length of upper bracket, as
specified in 5C-1-3/Table 3
PL = nominal pressure, p, in kN/m2 (tf/m2, Ltf/ft2), at the mid-length of lower bracket, as
specified in 5C-1-3/Table 3.
hU = length of the upper bracket, in m (ft), as indicated in 5C-1-4/Figure 2B-a
hL = length of the lower bracket, in m (ft), as indicated in 5C-1-4/Figure 2B-a
fs = permissible shear stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.45 Sm fy
KU and KL are given in 5C-1-4/Table 2.
Sm and fy, as defined in 5C-1-4/7.3.1.
For tankers without cross ties in the wing cargo tank, the required sectional area of the lower side
transverse is to extend to 0.15l from the toe of the lower bracket or 0.33l from the lower end of the span,
whichever is greater.
For tankers with one cross tie, the sectional area required for the lower portion of the transverse is to be
maintained up to the cross tie.

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

11.9 Minimum Thickness for Web Portion of Main Supporting Members (1997)
In general, the net thickness of the web plate of the main supporting members, except stringers in double
side structures, is to be not less than t, as obtained below:
t = 0.012L + 7.7 mm
= 0.144L × 10-3 + 0.303 in.
but t need not be taken greater than 11.0 mm (0.433 in.)
The net thickness of side stringers in double side structures is not to be less than t1 and t2, as specified
below:
t1 = 0.012L + 6.7 mm

= 0.144L × 10-3 + 0.264 in.

but t1 need not be taken greater than 10.0 mm (0.394 in.)

t2 = cs(Sm fy /E)1/2 mm (in.)

where
L = the length of the vessel, in m (ft), as defined in 3-1-1/3.1
c = 0.7N2 − 0.2, not to be less than 0.33
s = spacing of longitudinals, in mm (in.)
Sm = strength reduction factor, obtained from 5C-1-4/7.3.1 for the steel grade of the side
stringer
fy = minimum specified yield point of the side stringer material, in N/cm2 (kgf/cm2, lbf/in2)
N = Rd [(Q/Qd)(y/yn)]1/2 for side stringers above neutral axis
= Rb [(Q/Qb)(y/yn)]1/2 for side stringers below neutral axis
Q = material conversion factor 5C-1-4/5.1 for the side stringer under consideration
y = vertical distance, in m (ft), measured from the neutral axis of the hull girder
transverse section to the side stringer under consideration
E, Rb and Qb are as defined in 5C-1-4/7.3.1. Rd, Qd and yn are as defined in 5C-1-4/9.1.

11.11 Proportions
In general, webs, girders and transverses are not to be less in depth than specified below, as a percentage of
the span, lt, lb or lg, where applicable (see 5C-1-4/Figure 2A and 5C-1-4/Figure 2B). Alternative designs
with stiffness equivalent to the specified depth/length ratio and the required section modulus may be
considered, provided that the calculated results are submitted for review.
11.11.1 Deck Transverse
23% for deck transverses in wing cargo tanks of tankers with four side longitudinal bulkheads
where no deck girders are fitted (see 5C-1-4/Figure 2A-d, e and f).
12.5% for deck transverses in center cargo tanks of tankers with four side longitudinal bulkheads
where no deck girders are fitted (see 5C-1-4/Figure 2A-d, e and f). In this case, the depth
is also to be not less than that of the transverse in the wing tank.
12.5% for deck transverses without deck girders for tankers with centerline longitudinal
bulkhead (See 5C-1-4/Figure 2A-c).
8.5% for deck transverses in cargo tanks with one deck girder.
5.5% for deck transverses in cargo tanks with two deck girders.
3.5% for deck transverse in cargo tanks with three or more deck girders.

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

11.11.2 Deck Girder

20% for deck girders where only one is fitted in a tank.
12.5% for deck girders where two are fitted in a tank.
9.0% for deck girders where three or more are fitted in a tank.

11.11.3 Longitudinal Bulkhead Webs/Girders (2005)

14% for vertical webs of longitudinal bulkheads without strut and horizontal girders of
longituditudinal bulkheads.
9.0% for vertical webs of longitudinal bulkheads with one or more struts
11.11.4 Transverse Bulkhead Webs/Girders
20.0% for vertical webs of transverse bulkheads where only one is fitted in a tank.
12.5% for vertical webs of transverse bulkheads where two are fitted in a tank.
9.0% for vertical webs of transverse bulkheads where three or more are fitted in a tank.
28% for horizontal girders of transverse bulkheads in wing tanks for tankers with four side
longitudinal bulkheads (See 5C-1-4/Figure 2A-d, e and f).
20% for horizontal girders of transverse bulkheads in center tanks for tankers with four side
longitudinal bulkheads (See 5C-1-4/Figure 2A-d, e and f), but not less in depth than
horizontal girders in wing tanks
20% for horizontal girders of transverse bulkheads without vertical webs for tankers with
centerline longitudinal bulkhead (See 5C-1-4/Figure 2A-c)
10% for horizontal girders of transverse bulkhead with one vertical web in the cargo tank
7% for horizontal girders of transverse bulkhead with two or more vertical webs in the cargo
tank, except in the case where more than two vertical webs are fitted for tankers with
centerline longitudinal bulkheads (See 5C-1-4/Figure 2A-b), or more than five vertical
webs are fitted for tankers with outer longitudinal bulkheads only (See 5C-1-4/Figure 2A-
a). In that case, horizontal girders are not to be less in depth than 15% of the maximum
distance between two adjacent vertical webs or the end of span lb of the horizontal girder
and next vertical web.
In no case are the depths of supporting members to be less than three times the depth of the slots
for longitudinals. The thickness of the webs is to be not less than required by 5C-1-4/11.9.

11.13 Brackets
Generally, brackets are to have a thickness not less than that of the member supported, are to have flanges
or face plates at their edges and are to be suitably stiffened.

11.15 Web Stiffeners and Tripping Brackets

11.15.1 Web Stiffeners
Stiffeners are to be fitted for the full depth of the webs of the main supporting member at the
following intervals:
Floor every longitudinal
Side every longitudinal
Bulkhead every second stiffener
Deck every third longitudinal
Special attention is to be given to the stiffening of web plate panels close to change in contour of
the web or where higher strength steel is used.

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

Web stiffener attachment to the deep webs, longitudinals and stiffeners is to be effected by continuous
welds.
Where depth/thickness ratio of the web plating exceeds 200, a stiffener is to be fitted parallel to
the flange or face plate at approximately one-quarter depth of the web from the flange or face plate.
Alternative system of web-stiffening of the main supporting members may be considered based on
the structural stability of the web and satisfactory levels of the shear stresses in the welds of the
longitudinals to the web plates.
11.15.2 Tripping Bracket
Tripping brackets, arranged to support the flanges, are to be fitted at intervals of about 3 m (9.84
ft), close to any changes of section, and in line with the flanges of struts.

11.17 Slots and Lightening Holes

When slots and lightening holes are cut in transverses, webs, floors, stringers and girders, they are to be
kept well clear of other openings. The slots are to be neatly cut and well rounded. Lightening holes are to
be located midway between the slots and at about one-third of the depth of the web from the shell, deck or
bulkhead. Their diameters are not to exceed one-third the depth of the web. In general, lightening holes are
not to be cut in those areas of webs, floors, stringers, girders and transverses where the shear stresses are
high. Similarly, slots for longitudinals are to be provided with filler plates or other reinforcement in these
same areas. Where it is necessary to cut openings in highly stressed areas, they are to be effectively
compensated. Continuous fillet welds are to be provided at the connection of the filler plates to the web
and at the connection of the filler plate to the longitudinals.

FIGURE 8
Effectiveness of Brackets (1995)

Span
Span

d/2
d/4

ha ha

d d length
length
of bracket of bracket

Where face plate on the member is carried Where face plate on the member is not carried
along the face of the bracket. along the face of the bracket, and where the
face plate area on the bracket is at least one-half
the face plate area on the member.

Brackets are not to be considered effective beyond the point where the arm of the girder or web is 1.5 times the arm on
the bulkhead or base.

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

TABLE 1
Coefficient c2 For Deck Transverses (1995)
No cross ties Cross ties in wing cargo tank Cross ties in center cargo
Structural Arrangement (5C-1-4/Figure 2A-a, b, c and (5C-1-4/Figure 2A-d) tank
f) (5C-1-4/Figure 2A-e)
Location of Deck Transverse All cargo tanks Wing tank Center tank Wing tank Center tank
(1)
c2 0.40 0.37 0.13 0.40 0.14
Note
1 c2 = 0.50 for tankers with an oil-tight centerline bulkhead which will be loaded from one side only.

TABLE 2
Coefficients KU and KL for Side Transverses (1995)

Arrangement of Cross Ties KU (1) KL (1)

No cross ties
(5C-1-4/Figure 2A-a, b, c and f)
0.13 0.30
One cross tie in center cargo tank
(5C-1-4/Figure 2A-e)
One cross tie in wing cargo tank
(5C-1-4/Figure 2A-d) 0.09 0.21

Note:
1 For tankers without cross ties in wing cargo tank (5C-1-4/Figure 2A-a, b, c, e
and f) and having three or more side stringers, KU = 0.10 and KL = 0.22

13 Longitudinal and Transverse Bulkheads

13.1 Longitudinal Bulkhead Plating (1 July 2005)

The net thickness of the longitudinal bulkhead plating, in addition to complying with 5C-1-4/5.5, is to be
not less than t1, t2 and t3, as specified below:
t1 = 0.73s(k1 p/f1)1/2 mm (in.)

t2 = 0.73s(k2 p/f2)1/2 mm (in.)

t3 = cs(Sm fy /E)1/2 mm (in.)

but not less than 9.5 mm (0.37 in.) where
s = spacing of longitudinal bulkhead longitudinals, in mm (in.)
k1 = 0.342
k2 = 0.5
p = pressure at the lower edge of each plate, pi, or maximum slosh pressure, ps,
whichever is greater, in N/cm2 (kgf/cm2, lbf/in2).
In no case is p to be taken less than 2.06 N/cm2 (0.21kgf/cm2, 2.987 lbf/in2).
pi = pn in cargo tank, in N/cm2 (kgf/cm2, lbf/in2)

= pn – puo in ballast tank, in N/cm2 (kgf/cm2, lbf/in2)

pn is nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), at the lower edge of each plate, as defined in 5C-1-3/Table 3
for longitudinal bulkhead plating.

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

puo is also defined in 5C-1-4/9.1.

The net thickness, t3, may be determined based on Sm and fy of the hull girder strength material required at
the location under consideration.
ps = ks pis, not to be taken less than ks pis(mid)
pis = nominal slosh pressure, as specified in 5C-1-3/11.5.1
pis(mid) = nominal slosh pressure at the mid-tank of the bulkhead at the same height as the point
under consideration
ks = bt /lt, 0.9 ≥ ks ≥ 0.65 (ks = 0.9 for pis(mid))

f1 = permissible bending stress, in the longitudinal direction, in N/cm2 (kgf/cm2, lbf/in2)

= [1 − 0.28z/B − 0.52α1(SMRB /SMB)(y/yn)]Sm fy, below neutral axis

= [1 − 0.28z/B − 0.52α2(SMRD /SMD)(y/yn)]Sm fy, above neutral axis

bt and lt are the width and length, respectively, of the cargo tank being considered.

SMB/SMRB is not to be taken more than 1.2α1 or 1.4, whichever is lesser.

α1 = Sm1 fy1/Sm fy

α2 = Sm2 fy2/Sm fy
Sm = strength reduction factor of the steel grade for the longitudinal bulkhead plating
obtained from 5C-1-4/7.3.1
fy = minimum specified yield point of the longitudinal bulkhead plating, in N/cm2
(kgf/cm2, lbf/in2)
z = transverse distance, in m (ft), measured from the centerline of the section to the
bulkhead strake under consideration
yn = vertical distance, in m (ft), measured from the deck (bottom) to the neutral axis of the
section, when the strake under consideration is above (below) the neutral axis.
f2 = permissible bending stress, in the vertical direction, in N/cm2 (kgf/cm2, lbf/in2)
= Sm fy

c = 0.7N 2 − 0.2
c for the top strake is not to be taken less than 0.4Q1/2, but need not be greater than
0.45.
c for other strakes is not to be taken less than 0.33, but need not be greater than
0.45(Q/Qd)1/2 for strakes above the neutral axis nor greater than 0.45(Q/Qb)1/2 for
strakes below the neutral axis.
N = Rd[(Q/Qd)(y/yn)]1/2, for strake above the neutral axis
= Rb[(Q/Qb)(y/yn)]1/2, for strake below the neutral axis
y = vertical distance, in m (ft), measured from the neutral axis of the hull girder transverse
section to the upper edge (lower edge) of the bulkhead strake, when the strake under
consideration is above (below) the neutral axis for N
= vertical distance, in m (ft), measured from the neutral axis of the hull girder transverse
section to the lower edge of the bulkhead strake under consideration for f1
Q = material conversion factor in 5C-1-4/5.1 for the longitudinal bulkhead plating
B = vessel’s breadth, in m (ft), as defined in 3-1-1/5.

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

SMRB, SMB, Rb, Qb and E are as defined in 5C-1-4/7.3.1.

Sm1 and fy1 are as defined in 5C-1-4/7.5.
Rd and Qd are as defined in 5C-1-4/9.1.
SMRD, SMD, Sm2 and fy2 are as defined in 5C-1-4/9.5.
For plate panels above the neutral axis, t3 need not be taken greater than the value that satisfies the
following buckling requirement.
Mt
≤ fc
SM R

fc = fE for fE ≤ Prfy

⎡ fy ⎤
fc = fy ⎢1 − Pr (1 − Pr ) ⎥ for fE > Prfy
⎣ fE ⎦

where
2
c1π 2 E ⎛ t 3 ⎞
⎜ ⎟
fE =
( )
3 1 −ν 2 ⎝ s ⎠
c1 = 1.0 for plate panels between flat bars or bulb plates
= 1.1 for plate panels between angles or tee stiffeners
Pr = proportional linear elastic limit of the structure, may be taken as 0.6 for steel

ν = Poisson’s ratio, may be taken as 0.3 for steel

Mt = total sagging bending moment
SMR = section modulus at the center of the plate panel under consideration.
The minimum width of the top strake for the midship 0.4L is to be obtained from the following equation:
b = 5L + 800 mm for L ≤ 200 m
= 1800 mm for 200 < L ≤ 500 m
b = 0.06L + 31.5 in. for L ≤ 656 ft
= 70.87 in. for 656 < L ≤ 1640 ft
L = length of vessel, as defined in 3-1-1/3.1, in m (ft)
b = width of top strake, in mm (in.)

13.3 Transverse Bulkhead Plating (1999)

The net thickness of transverse bulkhead plating is to be not less than t, as specified below:
t = 0.73s(k2 p/f2)1/2 mm (in.)
but not less than 9.5 mm (0.37 in.)
where
s = spacing of transverse bulkhead stiffeners, in mm (in.)
k2 = 0.50

p = pi or maximum slosh pressure, ps, whichever is greater, in N/cm2 (kgf/cm2, lbf/in2)

In no case is p to be taken less than 2.06 N/cm2 (0.21 kgf/cm2, 2.987 lbf/in2).

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

pi = pn in cargo tank, in N/cm2 (kgf/cm2, lbf/in2)

= pn – puh in ballast tank, in N/cm2 (kgf/cm2, lbf/in2)

pn is nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), at the lower edge of each plate, as defined in
5C-1-3/Table 3 for transverse bulkhead plating.
puh is also defined in 5C-1-4/7.3.1.
ps = ks pis, not to be taken less than ks pis(mid)
pis = nominal slosh pressure, as specified in 5C-1-3/11.5.1
pis(mid) = nominal slosh pressure at the mid-tank of the bulkhead at the same height as the point
under consideration.
ks = lt/bt, 0.9 ≥ ks ≥ 0.65 (ks = 0.9 for pis(mid))

f2 = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)

= 0.85 Sm fy
Sm and fy are as defined in 5C-1-4/7.3.1.

lt, bt are defined in 5C-1-4/13.1.

Where the wing ballast tanks are U-shaped, the net thickness of transverse bulkhead plating in the wing
ballast tanks is also to be not less than as obtained from the above equation with the following substituted
for p and f2.
where
p = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), as specified for side shell structure
(item 3 case a) in 5C-1-3/Table 3, at the lower edge level of each transverse bulkhead
plate.
f2 = Sm fy, in N/cm2 (kgf/cm2, lbf/in2)
where the breadth of center tank exceeds 0.6B, the net thickness of transverse bulkhead plating in the
center tank ,outboard of 0.3B from the centerline of the tank, is also to be not less than as obtained from the
above equation with the following substituted for p and f2:

p = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), as specified for inner skin longitudinal
bulkhead structure (item 6 case a) in 5C-1-3/Table 3, at the lower edge level of each
transverse bulkhead plate.
f2 = Sm fy, in N/cm2 (kgf/cm2, lbf/in2)

13.5 Longitudinals and Vertical/Horizontal Stiffeners (1 July 2005)

The net section modulus of each individual longitudinal or vertical/horizontal stiffener on longitudinal and
transverse bulkheads, in association with the effective plating to which it is attached, is to be not less than
obtained from the following equation:
SM = M/fb cm3 (in3)

M = 1000c1 psl2/k N-cm (kgf-cm, lbf-in.)

where
k = 12 (12, 83.33)
c1 = 1.0 for longitudinals and horizontal stiffeners

= 1 + γl/10p for vertical stiffeners

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Section 4 Initial Scantling Criteria 5C-1-4

γ = specific weight of the liquid, ≥ 1.005 N/cm2-m (0.1025 kgf/cm2-m, 0.4444 lbf/in2-ft).
s = spacing of longitudinals or vertical/horizontal stiffeners, in mm (in.)
l = span of longitudinals or stiffeners between effective supports, in m (ft)
p = pressure, pi, in N/cm2 (kgf/cm2, lbf/in2), at the longitudinal or stiffener considered, as
specified in 5C-1-4/13.1 and 5C-1-4/13.3, or maximum slosh pressure, ps, whichever
is greater. For vertical stiffeners, pressure is to be taken at the middle of span of each
stiffener.
ps = c3 pis, not to be taken less than c3 pis(mid)
pis(mid) = nominal slosh pressure at the mid-tank of the bulkhead at the same height as the point
under consideration
pis = nominal slosh pressure, as specified in 5C-1-3/11.5.1
c3 = as specified below:
for transverse bulkheads
0.60 for angle or T-bar, 0.68 for bulb plate or flat bar, and 0.73 for corrugation, if tank length lt is
greater than 1.4 times tank width bt and no transverse swash bulkheads in the tank.
Otherwise, c3 = cst (cst = 1.0 for pis(mid))

cst = lt/bt, 1.0 ≥ cst ≥ 0.71

for longitudinal bulkheads
0.60 for angle or T-bar, 0.68 for bulb plate or flat bar and 0.73 for corrugation, if tank width bt is
greater than 1.4 times tank length lt and no longitudinal swash bulkheads in the tank.
Otherwise c3 = csl (csl = 1.0 for pis(mid))

csl = bt /lt, 1.0 ≥ csl ≥ 0.71

fb = permissible bending stresses, in N/cm2 (kgf/cm2, lbf/in2).

= 0.70 Sm fy for transverse bulkhead stiffeners
= 1.4[1.0 − 0.28(z/B) − 0.52α1(SMRB/SMB)(y/yn)]Sm fy ≤ 0.90Sm fy for longitudinal
bulkhead longitudinals below neutral axis
= 2.2[1.0 − 0.28(z/B) − 0.52α2(SMRD/SMD)(y/yn)]Sm fb ≤ 0.90Sm fy for longitudinal
bulkhead longitudinals above neutral axis
z = transverse distance, in m (ft), measured from the centerline of the vessel to the
longitudinal under consideration at its connection to the associated plate
h = vertical distance, in m (ft), measured from the tank bottom to the longitudinal under
consideration
H = depth of the tank, in m (ft)
B = vessel’s breadth, in m (ft), as defined in 3-1-1/5.
Sm, fy and α1 are as defined in 5C-1-4/7.5.

α2, y, yn, SMRD and SMD are as defined in 5C-1-4/9.5.

SMRB and SMB are as defined in 5C-1-4/7.3.1.
The effective breadth of plating, be, is as defined in line a) of 5C-1-4/Figure 6.

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

Where the wing ballast tanks are U-shaped, the net section modulus of transverse bulkhead stiffeners in the
wing ballast tanks is also to be not less than as obtained from the above equation with the following
substituted for p and fb:

p = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), as specified for side shell structure
(item 3 case a) in 5C-1-3/Table 3 at each transverse bulkhead stiffener level.
fb = Sm fy, in N/cm2 (kgf/cm2, lbf/in2)
Where the breadth of center tank exceeds 0.6B, the net section modulus of transverse bulkhead stiffeners in
the center tank, located outboard of 0.3B from the centerline of the tank, is also to be not less than as
obtained from the above equation with the following substituted for p and fb:

p = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), as specified for inner skin longitudinal
bulkhead structure (item 6 case a) in 5C-1-3/Table 3 at each transverse bulkhead
stiffener level.
fb = Sm fy, in N/cm2 (kgf/cm2, lbf/in2)
The net moment of inertia of longitudinals on the longitudinal bulkhead, with the associated effective
plating, within the region of 0.1D from the deck is to be not less than io, as specified in 5C-1-4/9.5.

15 Bulkheads – Main Supporting Members (1995)

15.1 General
The main supporting members of longitudinal and transverse bulkheads are to be arranged and designed, as
indicated in 5C-1-4/11.1.

15.3 Vertical Web on Longitudinal Bulkhead

15.3.1 Section Modulus of Vertical Web on Longitudinal Bulkhead (1997)
The net section modulus of the vertical web is to be not less than obtained from the following
equation (see also 5C-1-4/1.3).
SM = M/fb cm3 (in3)

M = 10,000kcps l 2b N-cm (kgf-m, lbf-in.)

where
k = 1.0 (1.0, 0.269)
lb = span of member, in m (ft), as indicated in 5C-1-4/Figure 2B-a. Where a cross
tie (in wing or center tank) is fitted and is located at a distance greater than
0.7lb from the deck transverse, the effective span of the vertical web may be
measured from the deck transverse to the cross tie and all coefficients
determined as if there were no cross ties. Where both the lower and upper
ends of the vertical web are fitted with a bracket of the same or larger size on
the opposite side, the span lb may be taken between the toes of the effective
lower and upper brackets.
s = spacing of vertical webs, in m (ft)
p = nominal pressure, in kN/m2 (tf/m2, Ltf/ft2), at the mid-span of the vertical
web, as specified in 5C-1-3/Table 3.
fb = permissible bending stress, in N/cm2 (kgf/cm2 lbf/in2)
= 0.70 Sm fy
Sm and fy are as defined in 5C-1-4/7.3.1.

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Section 4 Initial Scantling Criteria 5C-1-4

c is given in 5C-1-4/Table 3.
For tankers without cross ties, and fitted with an oil-tight centerline bulkhead, the required section
modulus of the web is to be maintained for 0.6lb, measured from the lower end of the web. The
value of the bending moment, M, used for calculation of the required section modulus of the
remainder of the web may be appropriately reduced, but by not more than 20%. Where the
centerline bulkhead is non-tight, the required section modulus is to be maintained throughout.
15.3.2 Web Sectional Area of Vertical Webs on Longitudinal Bulkheads
The net sectional area of the web portion of vertical members is to be not less than obtained from
the following equation:
A = F/fs cm2 (in2)
The shear force F, in N (kgf, lbf), may be obtained from the following equations (see also 5C-1-4/1.3).
F = 1000ks[KU l(PU + PL) − hUPU] for upper part of vertical web

= 1000ks[KL l(PU + PL) − hLPL] for lower part of vertical web

but F for lower part of vertical web is not to be less than
= 1000γ ksKL l(PU + PL)
where
k = 1.0 (1.0, 2.24)
PU = nominal pressure, p, in kN/m2 (tf/m2, Ltf/ft2), at the mid-length of upper
bracket, as specified in 5C-1-3/Table 3.
PL = nominal pressure, p, in kN/m2 (tf/m2, Ltf/ft2), at the mid-length of lower
bracket, as specified in 5C-1-3/Table 3.
l = span of the vertical web, in m (ft), as indicated in 5C-1-4/Figure 2B-a. Where
a cross tie (in wing or center tank) is fitted and is located at a distance greater
than 0.7l from the deck transverse, the effective span of the vertical web
may be measured from the deck transverse to the cross tie and all
coefficients determined as if there were no cross ties.
s = spacing of the vertical webs, in m (ft)
hU = length, in m (ft), of the upper bracket of the vertical web, as indicated in
5C-1-4/Figure 2B-a and 5C-1-4/Figure 8
hL = length, in m (ft), of the lower bracket of the vertical web, as indicated in
5C-1-4/Figure 2B-a and 5C-1-4/Figure 8
γ = 0.57 for tankers without cross ties, (5C-1-4/Figure 2A-b, c and f)
= 0.50 for tankers with one cross tie, (5C-1-4/Figure 2A-d and e)
fs = permissible shear stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.45 Sm fy
Sm and fy are as defined in 5C-1-4/7.3.1.
Coefficients KU and KL are given in 5C-1-4/Table 4.
For tankers without cross ties, the required sectional area of the lower part of the web is to be
maintained for 0.6l measured from the lower end of the web.
For tankers with one cross tie, the required sectional area of the lower part of the web is to be
maintained up to the cross tie.
In no case is the shear force for the lower part of the vertical web to be taken less than 120% of
that for the upper part of the vertical web.

106 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

TABLE 3
Coefficient c for Vertical Web on Longitudinal Bulkheads (2001)
Arrangement of Cross Ties For Upper Part For Lower Part
No Cross Ties
(5C-1-4/Figure 2A-b, c & f) 0.80
1) Tight Bhd
2) Non-tight Centerline Bhd 0.28
One Cross Tie in Center Tank,
0.14 0.31
(5C-1-4/Figure 2A-e)
One Cross Tie in Wing Cargo Tank,
0.18 0.36
(5C-1-4/Figure 2A-d)

TABLE 4
Coefficients KU and KL for Vertical Web on Longitudinal Bulkhead (2001)
Arrangement of Cross Ties KU KL
No Cross Ties
(5C-1-4/Figure 2A-b, c & f) 0.18 0.28
1) Tight Bhd
2) Non-tight Centerline Bhd. 0.09 0.14
One Cross Tie in Center or Wing Cargo Tank, 0.08 0.18
(5C-1-4/Figure 2A-d & e)

15.5 Horizontal Girder on Transverse Bulkhead

15.5.1 Section Modulus of Horizontal Girder on Transverse Bulkhead
The net section modulus of the horizontal girder is to be not less than obtained from the following
equation (see also 5C-1-4/1.3).
SM = M/fb cm3 (in3)

M = 10,000kcps l 2b N-cm (kgf-cm, lbf-in)

where
k = 1.0 (1.0, 0.269)
lb = span of the horizontal girders, in m (ft), as indicated in 5C-1-4/Figure 2B-b.
For tankers with four longitudinal bulkheads, (5C-1-4/Figure 2A-d, e and f), lb is to be taken not
less than 60% of the breadth of the wing cargo tanks.
s = sum of the half lengths, in m (ft), of the frames supported on each side of the
horizontal girder.
p = nominal pressure, in kN/m2 (tf/m2, Ltf/ft2), calculated at the mid-span of the
horizontal girder under consideration, as specified in 5C-1-3/Table 3.
fb = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.70 Sm fy
Sm and fy, as defined in 5C-1-4/7.3.1.

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

c for transverse bulkheads without vertical webs

= 0.73 for tankers with an oil-tight centerline bulkhead (5C-1-4/Figure 2A-c)
= 0.55 for tankers with a non-tight centerline bulkhead (5C-1-4/Figure 2A-c)
= 0.83 in wing cargo tanks of vessels with four longitudinal bulkheads
(5C-1-4/Figure 2A-d, e and f)
= 0.63 in the center tanks of vessels with four longitudinal bulkheads
(5C-1-4/Figure 2A-d, e and f)
c for transverse bulkheads with vertical webs
For 5C-1-4/Figure 2A-b, tankers with oil-tight centerline bulkhead and 5C-1-4/Figure 2A-a
= 0.73α2 for α < 0.5
= 0.467α + 0.0657
2
for 0.5 ≤ α ≤ 1.0
= 0.1973α + 0.3354 for α > 1.0
c is not to be taken less than 0.013 and need not be greater than 0.73.
For 5C-1-4/Figure 2A-b, tankers with a non-tight centerline bulkhead
= 0.55α2 for α < 0.5
= 0.35α + 0.05
2
for 0.5 ≤ α ≤ 1.0
= 0.15α + 0.25 for α > 1.0
c is not to be taken less than 0.013 and need not to be greater than 0.55.
α = 0.9(lst /lb)[(I/Iv)(sv/s)]1/ 4
if more than one vertical web is fitted on the bulkhead, average values of lst,
sv and Iv are to be used when these values are not the same for each web.
lst = span of the vertical web, in m (ft) (5C-1-4/Figure 2B-c)
sv = spacing of the vertical webs, in m (ft)
I, Iv = moments of inertia, in cm4 (in4), of the horizontal girder and the vertical web
clear of the end brackets.
15.5.2 Web Sectional Area of the Horizontal Girder on Transverse Bulkhead
The net sectional area of the web portion of the horizontal girder is to be not less than obtained
from the following equation:
A = F/fs cm2 (in2)
F = 1000 kscp(0.5l − he) N (kgf, lbf)
where
k = 1.0 (1.0, 2.24)
c = 0.80 for transverse bulkheads without vertical webs
= 0.72α 1/2
for transverse bulkheads with vertical webs for α ≥ 0.70
= 0.887α – 0.02 for transverse bulkheads with vertical webs for α < 0.7,
0.1 min. and 0.8 max.
l = distance, in m (ft), between longitudinal bulkheads, as indicated in
5C-1-4/Figure 2B-b
s = sum of the half lengths, in m (ft), on each side of the horizontal girder, of the
frames supported
he = length of the bracket, in m (ft), as indicated in 5C-1-4/Figure 2B-b

108 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

p and α are as defined in 5C-1-4/15.5.1.

fs = permissible shear stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.45 Sm fy
Sm and fy are as defined in 5C-1-4/7.3.1.

15.7 Vertical Web on Transverse Bulkhead

15.7.1 Section Modulus of Vertical Web on Transverse Bulkhead
The net section modulus of the vertical web is to be not less than obtained from the following
equation (see also 5C-1-4/1.3):
SM = M/fb cm3 (in3)

M = 10,000kcps l 2st N-cm (kgf-cm, lbf-in)

where
k = 1.0 (1.0, 0.269)
c = 0.83 for bulkheads without horizontal girders
= 0.83 − 0.52α (but not less than 0.3) for transverse bulkheads with horizontal
girders.
lst = span of the vertical web, in m (ft), (5C-1-4/Figure 2B-c )
s = spacing of vertical webs, in m (ft)
p = nominal pressure, in kN/m2 (tf/m2, Ltf/ft2), at the mid-span of the vertical
web, as specified in 5C-1-3/Table 3.
α = as defined in 5C-1-4/15.5.1, except that the values of s, lb and I are to be
averaged in the case that more than one horizontal girder is fitted on the
bulkhead.
fb = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.70 Sm fy
Sm and fy, as defined in 5C-1-4/7.3.1.
The required section modulus for the web is to be maintained for a distance of 0.60lst from the
lower end of the span. Above that point, the value of the bending moment, M, used for the
calculation of the required section modulus may be reduced by not more than 20%.
15.7.2 Web Sectional Area of Vertical Web on Transverse Bulkheads
The net sectional area of the web portion of vertical members is to be not less than obtained from
the following equation:
A = F/fs cm2 (in2)
The shear force F in N (kgf, lbf) may be obtained from the following equations (see also
5C-1-4/1.3).
F = 1000ks[0.18cl(PU + PL) − hUPU] for upper part of vertical web

F = 1000ks[0.30cl(PU + PL) − hLPL] or

120kscl(PU + PL) whichever is greater, for lower
part of vertical web

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

where
k = 1.0 (1.0, 2.24)
c = 1.0 for transverse bulkheads without horizontal girders
= 1.13 − 0.6α for transverse bulkheads with horizontal girders, 0.6 min.
and 1.0 max.
PU = nominal pressure, p, in kN/m2 (tf/m2, Ltf/ft2), at the mid-length of upper
bracket, as specified in 5C-1-3/Table 3
PL = nominal pressure, p, in kN/m2 (tf/m2, Ltf/ft2), at the mid-length of lower
bracket, as specified in 5C-1-3/Table 3
l = span of the vertical web, in m (ft), as indicated in 5C-1-4/Figure 2B-c
s = spacing of the vertical webs, in m (ft)
hU = length, in m (ft), of the upper bracket, as indicated in 5C-1-4/Figure 2B-c and
5C-1-4/Figure 8
hL = length, in m (ft), of the lower bracket, as indicated in 5C-1-4/Figure 2B-c and
5C-1-4/Figure 8
α is as defined in 5C-1-4/15.7.1.
fs = permissible shear stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.45 Sm fy
Sm and fy are as defined in 5C-1-4/7.3.1.
The required sectional area of the lower portion of the web is to be maintained for a distance of
0.15l from the toe of the lower bracket or 0.33l measured from the lower end of the span,
whichever is greater.
In no case is the shear force for the lower part of the vertical web to be taken less than 120% of
that for the upper part of the vertical web.

15.9 Minimum Web Thickness, Proportions, Brackets, Stiffeners, Tripping Brackets, Slots
and Lightening Holes
Requirements for these items are given in 5C-1-4/11.9, 5C-1-4/11.11, 5C-1-4/11.13, 5C-1-4/11.15 and
5C-1-4/11.17.

15.11 Cross Ties (1 July 2005)

Where cross ties are fitted as effective supports for the tank structural members, they are to be spaced so as
to divide the supported members into spans of approximately equal length. The axial load imposed on cross
ties, W, is to be not greater than the permissible load, Wa, both are as specified below (see also 5C-1-4/1.3).
Alternatively, W may be determined from finite element analyses, as specified in 5C-1-5/9, with the
combined load cases in 5C-1-3/9. However, in no case should W be taken less than 85% of that determined
from the approximate equation below. For this purpose, an additional load case is also to be investigated,
modifying load case 5 (of 5C-1-3/Table 1) with a full design draft and Kf0 = 1.0 for external pressure where
cross ties are located in wing cargo tanks. (See also 5C-1-5/9.1).
W = pbs kN (tf, Ltf)
Wa = 0.55fcAs kN (tf, Ltf)

fc = fE for fE ≤ Prfy

⎡ fy ⎤
fc = fy ⎢1 − Pr (1 − Pr ) ⎥ for fE > Prfy
⎣ fE ⎦

fE = π2E/(l/r)2

110 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

where
b = mean breadth of the area supported, in m (ft)
s = spacing of transverses, in m (ft)
p = nominal pressure, in kN/m2 (tf/m2, Ltf/ft2), at the center of the area supported by the
cross tie, as specified in 5C-1-3/Table 3, item 15
l = unsupported span of the cross tie, in cm (in.)
r = least radius of gyration of the cross tie, in cm (in.)
As = net cross section area of the cross tie, in cm2 (in2)
fy = minimum specified yield point of the material, in kN/cm2 (tf/cm2, Ltf/in2)
Pr = proportional linear elastic limit of the structure, may be taken as 0.6 for steel
E = 2.06 × 104 kN/cm2 (2.1 × 103 tf/cm2, 13.4 × 103 Ltf/in2)
Special attention is to be paid to the adequacy of the welded connections for transmission of the tensile
forces and also to the stiffening arrangements at the ends, in order to provide effective means for
transmission of the compressive forces into the webs. In addition, horizontal stiffeners are to be located in
line with and attached to the first longitudinal above and below the ends of the cross ties.

15.13 Nontight Bulkheads (1 July 2005)

Nontight bulkheads referred to in 5C-1-3/11.3.1 are to be fitted in line with transverse webs, bulkheads or
other structures with equivalent rigidity. They are to be suitably stiffened. Openings in the nontight bulkhead
are to have generous radii and their aggregate area is not to exceed 33%, nor to be less than 10% of the
area of the nontight bulkhead. The net thickness of nontight bulkheads is to be not less than 11.0 mm
(0.433 in.) for oil carriers with L less or equal to 300 meters and 12.0 mm (0.472 in.) for L over 300
meters. Section moduli of stiffeners and webs may be half of those required for watertight bulkheads in
3-2-9/5.3 and 3-2-9/5.7. In addition, the scantlings of the nontight bulkhead are to comply with the requirements
of 5C-1-5/3.3 and 5C-1-5/5.3.3 using a finite element model in conjunction with the combined load cases
in 5C-1-3/Table 1a.
Alternatively, the opening ratio and scantlings may be determined by an acceptable method of engineering
analysis.

17 Corrugated Bulkheads (1997)

17.1 General
All vertically corrugated transverse and longitudinal bulkheads in cargo tanks are to be designed in
compliance with the requirements specified in this subsection and the strength assessment criteria with
respect to yielding, buckling and ultimate strength, and fatigue, as specified in Section 5C-1-5.
In general, the approximation equations given below are applicable to vertical corrugations with corrugation
angles, φ (5C-1-4/Figure 10 or 5C-1-4/Figure 9), within the range between 60 and 90 degrees. For corrugation
angles less than 60 degrees and corrugation in the horizontal direction, direct calculations may be required.

17.3 Plating (1999)

The net thickness of the vertically corrugated plating is not to be less than t1, t2, t3 and t4, obtained from the
following equations:
t1 = 0.516k1a(pl/f1)1/2 in mm (in.) for flange and web plating
1/2
t2 = 0.42k2a(fy /E) in mm (in.) for flange plating
t3 = k(a/k3) (f3)1/2 10–3 in mm (in.) for flange plating
t4= 100F/(df4) in mm (in.) for web plating
but not less than 9.5 mm (0.37 in.)

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

where
k = 0.728 (2.28, 0.605)
a = width of flange plating, in mm (in.) (5C-1-4/Figure 9 or 5C-1-4/Figure 10)
c = width of web plating, in mm (in.) (5C-1-4/Figure 9 or 5C-1-4/Figure 10)
d = depth of corrugation, in mm (in.) (5C-1-4/Figure 9 or 5C-1-4/Figure 10)
φ = corrugation angle, (5C-1-4/Figure 9 or 5C-1-4/Figure 10)
k1 = (1 − c/a + c2/a2)1/2
k2 = f2/(0.73fy)

k3 = 7.65 − 0.26(c/a)2
F = shear force, in N (kgf, lbf), imposed on the web plating at the lower end of
corrugation span
= k4sl(0.375pl + 0.125pu)
k4 = 10 (10, 12)
s = spacing of corrugation, in mm (in.), i.e., a + ccos φ, (5C-1-4/Figure 9 or
5C-1-4/Figure 10)
l = span of corrugation, in m (ft), taken as the distance between lower and upper stools at
centerline
pl, pu = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), at the lower and upper ends of span,
respectively, as specified in 5C-1-3/Table 3
f1 = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.90 Sm fy
f2 = maximum vertical bending stress in the flange at the mid-depth of corrugation span to
be calculated from 5C-1-4/17.5 below, in N/cm2 (kgf/cm2, lbf/in2)
f3 = maximum vertical bending stress in the flange at the lower end of corrugation span to
be calculated from 5C-1-4/17.5 below, in N/cm2 (kgf/cm2, lbf/in2)
f4 = permissible shear stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.40 Sm fy
E, Sm and fy are as defined in 5C-1-4/7.3.1.
The plate thickness, as determined above based on the maximum anticipated pressures, is to be generally
maintained throughout the entire corrugated bulkhead, except that the net thickness of plating above 2/3 of
span, l, from the top of the lower stool may be reduced by 20%.

17.5 Stiffness of Corrugation (1999)

17.5.1 Depth/Length Ratio
The depth/length ratio (d/l) of the corrugation is not to be less than 1/15, where d and l are as
defined in 5C-1-4/17.3 above.
17.5.2 Section Modulus
The net section modulus for any unit corrugation is not to be less than obtained from the following
equation for all anticipated service loading conditions.
SM = M/fb cm3 (in3)

M = 1000(Ci/Cj)ps l o2 /k N-cm (kgf-cm, lbf-in)

112 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

where
k = 12 (12, 83.33)
lo = nominal length of the corrugation, in m (ft), measured from the mid-depth of
the lower stool to the mid-depth of the upper stool
p = (pu + pl)/2, N/cm2 (kgf/cm2, lbf/in2)

fb = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)

= 0.90 Sm fy, for lower end of corrugation span l

= ce fy ≤ 0.90Sm fy for the mid l/3 region of the corrugation

ce = 2.25/β − 1.25/β2 for β ≥ 1.25

= 1.0 for β < 1.25

β = (fy /E)1/2 a/tf
tf = net thickness of the corrugation flange, in mm (in.)
Ci = the bending moment coefficients, as given below

Values of Ci (All Bulkheads with Lower and Upper Stools)

Bulkhead Lower End of Mid-depth Upper End of
Span l Span l
Trans. Bhd:
(w/Long’l Bhd) C1 Cm1 0.80Cm1
(w/out Long’l Bhd) C2 Cm2 0.65Cm2
Long’l. Bhd. C3 Cm3 0.65Cm3

C1 = a1 + b1(kAdt /Bd)1/2 ≥ 0.6

where a1 = 0.95 − 0.26/Rb, b1 = −0.20 + 0.05/Rb

Cm1 = am1 + bm1(kAdt /Bd)1/2 ≥ 0.55

where am1 = 0.63 + 0.16/Rb, bm1 = –0.25 – 0.07/Rb

C2 = a2 + b2(kAdt /Bd)1/2 ≥ 0.6

where a2 = 0.84 – 0.07/Rb, b2 = –0.24 + 0.02/Rb

Cm2 = am2 + bm2(kAdt /Bd)1/2 ≥ 0.55

where am2 = 0.56 + 0.05/Rb, bm2 = –0.34 – 0.03/Rb

C3 = a3 + b3(kAdl/Ld)1/2 ≥ 0.6
where a3 = 1.07 – 0.21/Rb, b3 = –0.21 + 0.04/Rb

Cm3 = am3 + bm3(kAdl/Ld)1/2 ≥ 0.55

where am3 = 0.30 + 0.07/Rb, bm3 = –0.12 – 0.03/Rb
Cj = the bending moment factors due to sloshing effect

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

Values of Cj (All Bulkheads with Lower and Upper Stools)

Bulkhead Mid-depth Upper End of
Span l
Trans. Bhd: Cmj1 Cmj2
Long’l. Bhd. Cmj3 Cmj4

P P
Cmj1 = 1.83 – 0.74 ≥ 0.40 if < 0.95
Ps Ps

P
= 1.0 if ≥ 0.95
Ps

P Pn
Cmj2 = 3.73 – 2.36 ≥ 0.62 if < 0.90
Ps Ps

P
= 1.0 if ≥ 0.90
Ps

P P
Cmj3 = 4.14 – 3.14 ≥ 0.75 if < 1.00
Ps Ps

P
= 1.0 if ≥ 1.00
Ps

P P
Cmj4 = 2.36 – 1.71 ≥ 0.72 if < 1.15
Ps Ps

P
= 1.0 if ≥ 1.15
Ps

Ps = (psu + psl)/2 N/cm2 (kgf/cm2, lbf/in2)

P = (pu + pl)/2 N/cm2 (kgf/cm2, lbf/in2)

psl, psu = sloshing pressure, in N/cm2 (kgf/cm2, lbf/in2), at the lower and upper ends of
span, respectively, as specified in 5C-1-3/11.5, calculated at the same
locations indicated for pl and pu.
pl, pu = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), at the lower and upper ends of
span, respectively, as specified in 5C-1-3/Table 3, to be calculated at a
section located B/4 from the C.L. when the vessel has one or no longitudinal
bulkheads. For vessels with two longitudinal bulkheads, the nominal
pressure is to be calculated at a section located b/4 from the outboard
boundary of the center or the wing tank.
Rb = kHst(Bct + Bst)(1 + Lb/Bb + 0.5Hb/Lb)/(2Bb) for transverse bulkheads
= Hsl (Bcl + Bsl)(1 + Bb/Lb + 0.5Hb/Bb)/(2Lb) for longitudinal bulkheads
Adt = cross sectional area, in m2 (ft2), enclosed by the outside lines of upper stool
of transverse bulkhead
Adl = cross sectional area, in m2 (ft2), enclosed by the outside lines of upper stool
of longitudinal bulkheads
Bct = width of the bottom stool of transverse bulkhead, in m (ft), at the top
(5C-1-4/Figure 10 or 5C-1-4/Figure 9)
Bcl = width of the bottom stool of longitudinal bulkhead, in m (ft), at the top
(5C-1-4/Figure 10)

114 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

Bst = width of the bottom stool of transverse bulkhead, in m (ft), at the inner
bottom level (5C-1-4/Figure 10)
Bsl = width of the bottom stool of longitudinal bulkhead, in m (ft), at the inner
bottom level (5C-1-4/Figure 10)
Hb = double bottom height, in m (ft)
Hst = height of the bottom stool of transverse bulkhead, in m (ft), from the inner
bottom to the top (5C-1-4/Figure 10 or 5C-1-4/Figure 9)
Hsl = height of the bottom stool of longitudinal bulkhead, in m (ft), from the inner
bottom to the top (5C-1-4/Figure 10)
Bb = transverse distance, in m (ft), between hopper tanks at the inner bottom level
(5C-1-4/Figure 10 or 5C-1-4/Figure 9)
Bd = transverse distance, in m (ft), between upper wing tanks or between upper wing
tank and centerline deck structure, at the deck level (see 5C-1-4/Figure 10 or
5C-1-4/Figure 9).
Lb = longitudinal distance, in m (ft), between bottom stools in the loaded tanks at
the inner bottom level (5C-1-4/Figure 10 or 5C-1-4/Figure 9)
Ld = longitudinal distance, in m (ft), between upper stools in the loaded tanks at
the deck level (5C-1-4/Figure 10)
k = 1 (1, 3.2808)
B = breadth of vessel, as defined in 3-1-1/5, in m (ft)
b = width of tank under consideration, in m (ft)
a, l, s, pu and pl are as defined in 5C-1-4/17.3 above.
E is as defined in 5C-1-4/7.3.
Sm and fy are as defined in 5C-1-4/7.5.
The developed net section modulus SM may be obtained from the following equation, where a, c,
d, tf (net), and tw(net), all in cm (in.), are as indicated in 5C-1-4/Figure 9.
SM = d(3atf + ctw)/6 cm3 (in3)

17.7 Bulkhead Stools

17.7.1 Lower Stool (2004)
The height of the lower stool is to be not less than three times the minimum depth of corrugation
required by 5C-1-4/17.5.1 above. The net thickness and material of the stool top plate is not to be
less than that required for the bulkhead plating in 5C-1-4/17.3 above. The net thickness and
material of the upper portion of vertical or sloping stool side plate within the region of one meter
from the stool top is not to be less than the required flange plate thickness to meet the bulkhead
stiffness requirement at the lower end of the corrugation in 5C-1-4/17.5 above. The net thickness
of the stool side plating and the net section modulus of the stool side stiffeners are not to be less
than those required for plane transverse or longitudinal bulkhead plating and stiffeners in
5C-1-4/13.1, 5C-1-4/13.3 and 5C-1-4/13.5, with the corresponding tank pressure specified in
5C-1-3/Table 3. The ends of stool side vertical stiffeners are to be attached to brackets at the upper
and lower ends of the stool.
The extension of the top plate beyond the corrugation is not to be less than the as-built flange
thickness of the corrugation. The stool bottom is to be installed in line with double bottom floors
or girders, fitted with proper brackets, and diaphragms are to be provided in the stool to effectively
support the panels of the corrugated bulkhead. The width of the stool at the inner bottom is to be
not less than 2.5 times the mean depth of the corrugation. Scallops in the brackets and diaphragms
in way of the top and bottom connections to the plates and in the double bottom floors or girders
are to be avoided.

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

17.7.2 Upper Stool

The upper stool is to have a depth generally not less than twice the minimum depth of corrugation,
as specified in 5C-1-4/17.5, and is to be properly supported by girders or deep brackets.
The width of the stool bottom plate should generally be the same as that of the lower stool top
plate. The net thickness of the stool bottom plate should generally be the same as that of the
bulkhead plating, and the net thickness of the lower portion of the stool side plate is not to be less
than 80% of that required for the bulkhead plating in 5C-1-4/17.3 above for the upper one-third
portion of the bulkhead. The net thickness of the stool side plating and the net section modulus of
the stool side stiffeners are not to be less than those required for plane transverse bulkhead plating
and stiffeners in 5C-1-4/13.1, 5C-1-4/13.3 and 5C-1-4/13.5, with the corresponding tank pressure
specified in 5C-1-3/Table 3. The ends of stool side stiffeners are to be attached to brackets at the
upper and lower ends of the stool. Brackets or diaphragms are to be fitted to effectively support
the web panels of the corrugated bulkhead. Scallops in the brackets and diaphragms in way of the
connection to the stool bottom plate are to be avoided.
17.7.3 Alignment (2001)
Stool side vertical stiffeners and their brackets in the lower stool of the transverse bulkhead should
align with the inner bottom longitudinal to provide appropriate load transmission between the
stiffening members.

17.9 End Connections (1 July 2001)

The structural arrangements and size of the welding at the ends of corrugations are to be designed to
develop the required strength of the corrugated bulkhead. Where shedder plates (slanting plates) are fitted
at the end connection of the corrugation to the lower stool, appropriate means are to be provided to prevent
the possibility of gas pockets being formed in way of these plates within the cargo tanks.
Welding for all connections and joints is to be in compliance with the Rules. The welded connection of the
bulkhead to the stools within 10% of the depth of the corrugation from the outer surface of the corrugation,
d1, is to be double continuous with fillet size not less than 0.7 times the thickness of bulkhead plating or
penetration welds of equal strength (see 5C-1-4/Figure 11).

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

FIGURE 9
Definition of Parameters for Corrugated Bulkhead (1997)
(Tankers without Longitudinal Bulkhead at Centerline)
Bd

Bb

L
C

Adt

lo l

Bct

Hst

Hb Bst Lb

c
d tw
φ (NET)

s tf (NET)

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

FIGURE 10
Definition of Parameters for Corrugated Bulkhead (1997)
(Tankers with Longitudinal Bulkhead at Centerline)
Ad l
Bd

lo l
Bc l

Hs l
Bb
Bs l

L
C
Adt

Ld

lo l

Bct

Hst

Hb Bst Lb

c
d tw
φ (NET)

s tf (NET)

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-1-4

FIGURE 11
Corrugated Bulkhead End Connections
t (ACTUAL)

0.1d1
d1

0.7t (t = ACTUAL)

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PART Section 5: Total Strength Assessment

5C
CHAPTER 1 Vessels Intended to Carry Oil in Bulk (150 meters
(492 feet) or more in Length)

SECTION 5 Total Strength Assessment

1 General Requirements

1.1 General (1995)

In assessing the adequacy of the structural configuration and the initially selected scantlings, the strength
of the hull girder and the individual structural member or element is to be in compliance with the failure
criteria specified in 5C-1-5/3 below. In this regard, the structural response is to be calculated by performing a
structural analysis, as specified in 5C-1-5/9, or by other equivalent and effective means. Due consideration
is to be given to structural details, as specified in 5C-1-4/1.5.

1.3 Loads and Load Cases (1995)

In determination of the structural response, the combined load cases given in 5C-1-3/9.3 are to be considered
together with sloshing loads specified in 5C-1-3/11. Bowflare/bottom slamming and other loads, as specified
in 5C-1-3/13, are also to be considered as necessary.

1.5 Stress Components (1995)

The total stress in stiffened plate panels are divided into the following three categories:
1.5.1 Primary
Primary stresses are those resulting from hull girder bending. The primary bending stresses may
be determined by simple beam method using the specified total vertical and horizontal bending
moments and the effective net hull girder section modulus at the section considered. These
primary stresses, designated by fL1 (fL1V, fL1H for vertical and horizontal bending, respectively),
may be regarded as uniformly distributed across the thickness of plate elements, at the same level
measuring from the relevant neutral axis of the hull girder.
1.5.2 Secondary
Secondary stresses are those resulting from bending of large stiffened panels between longitudinal
and transverse bulkheads, due to local loads in an individual cargo or ballast tank.
The secondary bending stresses, designated by fL2 or fT2, are to be determined by performing a 3D
FEM analysis, as outlined in this section.
For stiffened hull structures, there is another secondary stress due to the bending of longitudinals
or stiffeners with the associated plating between deep supporting members or floors. The latter
secondary stresses are designated by f L*2 or f T*2 , and may be approximated by simple beam
theory.
The secondary stresses, fL2, fT2, f L*2 or f T*2 , may be regarded as uniformly distributed in the
flange plating and face plates.
1.5.3 Tertiary
Tertiary stresses are those resulting from the local bending of plate panels between stiffeners. The
tertiary stresses, designated by fL3 or fT3, can be calculated from classic plate theory. These stresses
are referred to as point stresses at the surface of the plate.

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 5 Total Strength Assessment 5C-1-5

3 Failure Criteria – Yielding

3.1 General
The calculated stresses in the hull structure are to be within the limits given below for the entire combined
load cases specified in 5C-1-3/9.3.

3.3 Structural Members and Elements (1999)

For all structural members and elements, such as longitudinals/stiffeners, web plates and flanges, the
combined effects of all of the calculated stress components are to satisfy the following limits:
fi ≤ Sm fy
where
fi = stress intensity

= ( f L2 + f T2 − fL fT + 3 f LT
2 1/2
) N/cm2 (kgf/cm2, lbf/in2)
fL = calculated total in-plane stress in the longitudinal direction including primary and
secondary stresses

= fL1 + fL2 + f L*2 N/cm2 (kgf/cm2, lbf/in2)

fL1 = direct stress due to the primary (hull girder) bending, N/cm2 (kgf/cm2, lbf/in2)
fL2 = direct stress due to the secondary bending between bulkheads in the longitudinal
direction, N/cm2 (kgf/cm2, lbf/in2)
f L*2 = direct stress due to local bending of longitudinal between transverses in the
longitudinal direction, N/cm2 (kgf/cm2, lbf/in2)
fT = calculated total direct stress in the transverse/vertical direction, including secondary
stresses

= fT1 + fT2 + f T*2 N/cm2 (kgf/cm2, lbf/in2)

fLT = calculated total in-plane shear stress, N/cm2 (kgf/cm2, lbf/in2)
fT1 = direct stress due to sea and cargo load in the transverse/vertical direction, N/cm2
(kgf/cm2, lbf/in2)
fT2 = direct stress due to the secondary bending between bulkheads in the
transverse/vertical direction, N/cm2 (kgf/cm2, lbf/in2)
f T*2 = direct stress due to local bending of stiffeners in the transverse/vertical direction,
N/cm2 (kgf/cm2, lbf/in2)
fy = specified minimum yield point, N/cm2 (kgf/cm2, lbf/in2)
Sm = strength reduction factor, as defined in 5C-1-4/7.3.1
For this purpose, f L*2 and f T*2 in the flanges of longitudinal and stiffener at the ends of span may be
obtained from the following equation:

f L*2 ( f T*2 ) = 0.071spl2/SML(SMT) N/cm2 (kgf/cm2, lbf/in2)

where
s = spacing of longitudinals (stiffeners), in cm (in.)
l = unsupported span of the longitudinal (stiffener), in cm (in.)
p = net pressure load, in N/cm2 (kgf/cm2, lbf/in2), for the longitudinal (stiffener)
SML (SMT) = net section modulus, in cm3 (in3), of the longitudinal (stiffener)

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 5 Total Strength Assessment 5C-1-5

3.5 Plating (1 July 2005)

For plating away from knuckle or cruciform connections of high stress concentrations and subject to both
in-plane and lateral loads, the combined effects of all of the calculated stress components are to satisfy the
limits specified in 5C-1-5/3.3 with fL and fT modified as follows:

fL = fL1 + fL2 + f L*2 + fL3 N/cm2 (kgf/cm2, lbf/in2)

fT = fT1 + fT2 + f T*2 + fT3 N/cm2 (kgf/cm2, lbf/in2)

where
fL3, fT3 = plate bending stresses between stiffeners in the longitudinal and transverse directions,
respectively, and may be approximated as follows.
fL3 = 0.182p(s/tn)2 N/cm2 (kgf/cm2, lbf/in2)
fT3 = 0.266p(s/tn)2 N/cm2 (kgf/cm2, lbf/in2)
p = lateral pressures for the combined load case considered (see 5C-1-3/9), in N/cm2
(kgf/cm2, lbf/in2)
s = spacing of longitudinals or stiffeners, in mm (in.)
tn = net plate thickness, in mm (in.)
For plating within two longitudinals or stiffeners from knuckle or cruciform connections of high stress
concentrations, the combined effects of the calculated stress components are to satisfy the following stress
limit:
fi ≤ 0.80 Sm fy
where
fi = stress intensity

= ( f L2 + f T2 − fL fT + 3 f LT
2 1/2
) N/cm2 (kgf/cm2, lbf/in2)
fL = calculated total in-plane stress in the longitudinal direction including primary and
secondary stresses
= fL1 + fL2 N/cm2 (kgf/cm2, lbf/in2)
fT = calculated total direct stress in the transverse/vertical direction, including secondary
stresses
= fT1 + fT2 N/cm2 (kgf/cm2, lbf/in2)
In addition, the failure criteria for knuckle or cruciform connections in 5C-1-5/11 are to be complied with.

fL1, fL2, f L*2 , fT1, fT2 and f T*2 are as defined in 5C-1-5/3.3.

5 Failure Criteria – Buckling and Ultimate Strength (1995)

5.1 General
5.1.1 Approach
The strength criteria given here correspond to either serviceability (buckling) state limits or
ultimate state limits for structural members and panels, according to the intended functions and
buckling resistance capability of the structure. For plate panels between stiffeners, buckling in the
elastic range is acceptable, provided that the ultimate strength of the structure satisfies the specified
design limits. The critical buckling stresses and ultimate strength of structures may be determined
based on either well-documented experimental data or a calibrated analytical approach. When a
detailed analysis is not available, the equations given in Appendix 5C-1-A2 may be used to assess
the buckling strength.

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 5 Total Strength Assessment 5C-1-5

5.1.2 Buckling Control Concepts

The strength criteria in 5C-1-5/5.3 through 5C-1-5/5.11 are based on the following assumptions
and limitations with respect to buckling control in design.
5.1.2(a) The buckling strength of longitudinals and stiffeners is generally greater than that of the
plate panels they support.
5.1.2(b) All longitudinals with their associated effective plating are to have moments of inertia
not less than io given in 5C-1-A2/11.1.
5.1.2(c) The main supporting members, including transverses, girders and floors, with their
associated effective plating are to have the moments of inertia not less than Is given in 5C-1-A2/11.5.
In addition, tripping (e.g., torsional instability) is to be prevented, as specified in 5C-1-A2/9.5.
5.1.2(d) Face plates and flanges of girders, longitudinals and stiffeners are proportioned such that
local instability is prevented. (See 5C-1-A2/11.7)
5.1.2(e) Webs of longitudinals and stiffeners are proportioned such that local instability is
prevented. (See 5C-1-A2/11.9).
5.1.2(f) Webs of girders, floors and transverses are designed with proper proportions and stiffening
systems to prevent local instability. Critical buckling stresses of the webs may be calculated from
equations given in 5C-1-A2/3.
For structures which do not satisfy these assumptions, a detailed analysis of buckling strength
using an acceptable method is to be submitted for review.

5.3 Plate Panels

5.3.1 Buckling State Limit (1 July 2005)
The buckling state limit for plate panels between stiffeners is defined by the following equation:
(fLb/fcL)2 + (fTb/fcT)2 + (fLT/fcLT)2 ≤ 1.0
where
fLb = fL1 + fL2 = calculated total compressive stress in the longitudinal direction for the plate,
in N/cm2 (kgf/cm2, lbf/in2), induced by bending of the hull girder and large
stiffened panels between bulkheads
fTb = fT1 + fT2 = calculated total compressive stress in the transverse/vertical direction, in
N/cm2 (kgf/cm2, lbf/in2)
fLT = calculated total in-plane shear stress, in N/cm2 (kgf/cm2, lbf/in2)
fcL, fcT and fcLT are the critical buckling stresses corresponding to uniaxial compression in the
longitudinal, transverse/vertical directions and edge shear, respectively, in N/cm2 (kgf/cm2, lbf/in2),
and may be determined from the equations given in 5C-1-A2/3.
fL, fT and fLT are to be determined for the panel in question under the load cases specified in 5C-1-3/9
including the primary and secondary stresses, as defined in 5C-1-5/3.1.
5.3.2 Effective Width
When the buckling state limit specified in 5C-1-5/5.3.1 above is not satisfied, the effective width
bwL or bwT of the plating given below is to be used instead of the full width between longitudinals,
s, for determining the effective hull girder section modulus, SMe, specified in 5C-1-5/5.13, and
also for verifying the ultimate strength, as specified in 5C-1-5/5.3.3 below. When the buckling
state limit in 5C-1-5/5.3.1 above is satisfied, the full width between longitudinals, s, may be used
as the effective width, bwL, for verifying the ultimate strength of longitudinals and stiffeners specified
in 5C-1-5/5.5, and for determining the effective hull girder section modulus SMe specified in
5C-1-5/5.13 below.

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Section 5 Total Strength Assessment 5C-1-5

5.3.2(a) For long plate:

bwL /s = C

C = 2.25/β − 1.25/β2 for β ≥ 1.25

= 1.0 for β < 1.25
β = (fy/E)1/2s/tn
s, tn and E are as defined in 5C-1-5/5.3.1 above.
fy = specified minimum yield point of the material, in N/cm2 (kgf/cm2, lbf/in2)
5.3.2(b) (1999) For wide plate (compression in transverse direction):
bwT /l = Cs/l + 0.115(1 − s/l)(1 + 1/β2)2 ≤ 1.0
where
l = spacing of transverses, in cm (in.)
s = longitudinal spacing, in cm (in.)
C, β are as defined in 5C-1-5/5.3.2(a) above.
5.3.3 Ultimate Strength (1 July 2005)
The ultimate strength of a plate panel between stiffeners is to satisfy all of the following equations:
(fLb/fuL)2 + (fLT /fuLT)2 ≤ Sm

(fTb/fuT)2 + (fLT /fuLT)2 ≤ Sm

(fLb/fuL)2 + (fTb/fuT)2 − η(fLb/fuL) (fTb/fuT) + (fLT /fuLT)2 ≤ Sm

where
fLb, fTb and fLT are as defined in 5C-1-5/5.3.1 above.
Sm is as defined in 5C-1-4/7.3.1.

η = 1.5 − β/2 ≥ 0
β is as defined in 5C-1-5/5.3.2 above.
fuL, fuT and fuLT are the ultimate strengths with respect to uniaxial compression and edge shear,
respectively, and may be obtained from the following equations, except that they need not be
taken less than the corresponding critical buckling stresses specified in 5C-1-5/5.3.1 above.
fuL = fybwL /s

fuT = fybwT /l

fuLT = fcLT + 0.5(fy − 3 fcLT)/(1 + α + α2)1/2

where
α = l/s
fy, bwL, bwT, s, l and fcLT are as defined above.
For assessing the ultimate strength of plate panels between stiffeners, special attention is to be
paid to the longitudinal bulkhead plating in the regions of high hull girder shear forces and the
bottom and inner bottom plating in the mid portion of cargo tanks subject to bi-axial compression.

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Section 5 Total Strength Assessment 5C-1-5

5.5 Longitudinals and Stiffeners

5.5.1 Beam-Column Buckling State Limits and Ultimate Strength (2002)
The buckling state limits for longitudinals and stiffeners are considered as the ultimate state limits
for these members and are to be determined as follows:
fa/(fcaAe/A) + mfb/fy ≤ Sm
where
fa = nominal calculated compressive stress

= P/A, N/cm2 (kgf/cm2, lbf/in2)

P = total compressive load, N (kgf, lbf)
fca = critical buckling stress, as given in 5C-1-A2/5.1, N/cm2 (kgf/cm2, lbf/in2)

A = total net sectional area, cm2 (in2)

= As + stn
As = net sectional area of the longitudinal, excluding the associated plating, cm2 (in2)

Ae = effective net sectional area, cm2 (in2)

= AS + bwLtn
bwL = effective width, as specified in 5C-1-5/5.3.2 above

E = Young’s modulus, 2.06 × 107 N/cm2 (2.1 × 106 kgf/cm2, 30 × 106 lbf/in2) for
steel
fy = minmum specified yield point of the longitudinal or stiffener under
consideration, N/cm2 (kgf/cm2, lbf/in2)
fb = bending stress, N/cm2 (kgf/cm2, lbf/in2)
= M/SMe
M = maximum bending moment induced by lateral loads
= cm psl2/12 N-cm (kgf-cm, lbf-in)
cm = moment adjustment coefficient, and may be taken as 0.75

p = lateral pressure for the region considered, N/cm2 (kgf/cm2, lbf/in2)

s = spacing of the longitudinals, cm (in.)
SMe = effective section modulus of the longitudinal at flange, accounting for the
effective breadth, be, cm3 (in3)
be = effective breadth, as specified in 5C-1-4/Figure 6, line b
m = amplification factor
= 1/[1 − fa/π2E(r/l)2] ≥ 1.0
Sm is as defined in 5C-1-4/7.3.1.

r and l are as defined in 5C-1-A2/5.1.

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Section 5 Total Strength Assessment 5C-1-5

5.5.2 Torsional-Flexural Buckling State Limit (2002)

In general, the torsional-flexural buckling state limit of longitudinals and stiffeners is to satisfy the
ultimate state limits given below:
fa /( fct Ae /A) ≤ Sm
where
fa = nominal calculated compressive stress in N/cm2 (kgf/cm2, lbf/in2), as defined
in 5C-1-5/5.5.1 above
fct = critical torsional-flexural buckling stress in N/cm2 (kgf/cm2, lbf/in2), and
may be determined by equations given in 5C-1-A2/5.3.
Ae and A are as defined in 5C-1-5/5.5.1 above and Sm is as defined in 5C-1-4/7.3.1.

5.7 Stiffened Panels

5.7.1 Large Stiffened Panels between Bulkheads
For a double hull tanker, assessment of buckling state limit is not required for the large stiffened
panels of the bottom and inner bottom structures, side shell and inner skin. Assessments of the
buckling state limits are to be performed for large stiffened panels of the deck structure and other
longitudinal bulkheads. In this regard, the buckling strength is to satisfy the following condition
for uniaxially or orthogonally stiffened panels.
(fL1/fcL)2 + (fT1/fcT)2 ≤ Sm
where
fL1, fT1 = the calculated average compressive stresses in the longitudinal and
transverse/vertical directions, respectively, as defined in 5C-1-5/3.3 above
fcL, fcT = the critical buckling stresses for uniaxial compression in the longitudinal and
transverse direction, respectively, and may be determined in accordance with
5C-1-A2/7, in N/cm2 (kgf/cm2, lbf/in2)
Sm = strength reduction factor, as defined in 5C-1-4/7.3.1

5.7.2 Uniaxially Stiffened Panels between Transverses and Girders

The bucking strength of uniaxially stiffened panels between deep transverses and girders is also to
be examined in accordance with the specifications given in 5C-1-5/5.7.1 above by replacing fL1
and fT1 with fLb and fTb, respectively. fLb and fTb are as defined in 5C-1-5/5.3.1 above.

5.9 Deep Girders and Webs

5.9.1 Buckling Criteria
In general, the stiffness of the web stiffeners along the depth of the web plating is to be in
compliance with the requirements of 5C-1-A2/11.3. Web stiffeners which are oriented parallel to
and near the face plate, and thus subject to axial compression, are also to satisfy the limits
specified in 5C-1-5/5.5, considering the combined effect of the compressive and bending stresses
in the web. In this case, the unsupported span of these parallel stiffeners may be taken between
tripping brackets, as applicable.
The buckling strength of the web plate between stiffeners and flange/face plate is to satisfy the
limits specified below.

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 5 Total Strength Assessment 5C-1-5

5.9.1(a) For web plate:

(fLb/fcL)2 + (fb/fcb)2 + (fLT /fcLT)2 ≤ Sm
where
fLb = calculated uniform compressive stress along the length of the girder, N/cm2
(kgf/cm2, lbf/in2)
fb = calculated ideal bending stresses, in N/cm2 (kgf/cm2, lbf/in2)
fLT = calculated total in-plane shear stress, in N/cm2 (kgf/cm2, lbf/in2)
Sm = strength reduction factor, as defined in 5C-1-4/7.3.1
fLb, fb and fLT are to be calculated for the panel in question under the combined load cases specified
in 5C-1-3/9.3.
fcLb, fcb and fcLT are critical buckling stresses with respect to uniform compression, ideal bending
and shear, respectively, and may be determined in accordance with Appendix 5C-1-A2.
In the determination of fcL and fcLT, the effects of openings are to be considered.
5.9.1(b) For face plate and flange. The breadth to thickness ratio of face plate and flange is to
satisfy the limits given in 5C-1-A2/11.
5.9.1(c) For large brackets and sloping webs. The buckling strength is to satisfy the limits
specified in 5C-1-5/5.9.1(a) above for web plate.
5.9.2 Tripping
Tripping brackets are to be provided in accordance with 5C-1-A2/9.5.

5.11 Corrugated Bulkheads (1997)

5.11.1 Local Plate Panels
5.11.1(a) Buckling criteria. The buckling strength of the flange and web plate panels is not to be
less than that specified below.
(fLb/Rl fcL)2 + (fTb/Rt fcT)2 + (fLT /fcLT)2 ≤ Sm for flange panels

(fLb/Rl fcL)2 + (fb/fcb)2 + (fLT /fcLT)2 ≤ Sm for web panels

All of the parameter definitions and calculations are as specified in 5C-1-5/5.3.1 and 5C-1-5/5.9.1(a),
except that fLb is the average compressive stress at the upper and lower ends of the corrugation,
and an average value of fTb, fLT and fb, calculated along the entire length of the panel, should be
used in the above equation.
5.11.1(b) Ultimate strength. The ultimate strength of flange panels in the middle one-third of the
depth are to satisfy the following criteria, considering a portion of flange panel having a length of
three times the panel width, a, with the worst bending moments in the mid-depth region for all
load cases.
(fLb/fuL)2 + (fTb/fuT)2 ≤ Sm
where
fLb = the calculated average compressive bending stress in the region within 3a in
length, N/cm2 (kgf/cm2, lbf/in2)
fTb = horizontal compressive stresses, as specified in 5C-1-5/5.11.1(a) above
fuL and fuT may be calculated in accordance with 5C-1-5/5.3.3 above.

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 5 Total Strength Assessment 5C-1-5

5.11.2 Unit Corrugation

Any unit corrugation of the bulkhead may be treated as a beam column and is to satisfy the
buckling criteria (same as the ultimate strength) specified in 5C-1-5/5.5.1. The ultimate bending
stress is to be determined in accordance with 5C-1-A2/5.5.
5.11.3 Overall Buckling
The buckling strength of the entire corrugation is to satisfy the equation given in 5C-1-5/5.7.1
with respect to the biaxial compression by replacing the subscripts “L” and “T” with “V” and “H”
for the vertical and horizontal directions, respectively.

5.13 Hull Girder Ultimate Strength

In addition to the strength requirements specified in 5C-1-4/3.1, the maximum longitudinal bending stresses
in the deck and bottom plating for the combined load cases given in 5C-1-3/9.3 are to be not greater than
that given in 5C-1-5/5.13.1 below.
5.13.1
fL ≤ Sm fy
where
fL = total direct stress in the longitudinal direction, N/cm2 (kgf/cm2, lbf/in2)
= fb1 + fb2

fb1 = effective longitudinal bending stress, N/cm2 (kgf/cm2, lbf/in2)

= Mt /SMe
Mt = Ms + ku kc Mw, ku = 1.15, kc = 1.0, N-cm (kgf-cm, lbf-in)

SMe = effective section modulus, as obtained from 5C-1-5/5.13.2 below, cm3 (in3)
Sm = strength reduction factor, as defined in 5C-1-4/7.3.1
fy = minimum specified yield point of the material, N/cm2 (kgf/cm2, lbf/in2)
fb2 = secondary bending stress of large stiffened panel between longitudinal
bulkheads and transverse bulkheads, N/cm2 (kgf/cm2, lbf/in2)
5.13.2 Calculation of SMe (2010)
For assessing the hull girder ultimate strength, the effective section modulus is to be calculated,
accounting for the buckling of plate panels and shear lag effects, as applicable.
5.13.2(a) Effective width. The effective widths of the side, bottom shell, inner bottom plating and
longitudinal bulkhead plating are to be used instead of the full width between longitudinals. The
effective width, bwL is given in 5C-1-5/5.3 above.
5.13.2(b) Shear lag. For double hull tankers without longitudinal bulkheads (except the inner
skins), the effective breadths, Be, of the deck and inner and outer bottom plating, are to be
determined based on the cL/b ratio as defined below.
cL/b = 12 10 9 8 7 6 5 4
2Be/B = 0.98 0.96 0.95 0.93 0.91 0.88 0.84 0.78
where
cL is the length between two points of zero bending moment, away from the midship, and may be
taken as 60% of the vessel length.
b is the distance from the centerline of the vessel to the center of the side ballast tank, as shown in
5C-1-5/Figure 1.

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 5 Total Strength Assessment 5C-1-5

For tankers with a centerline swash or oil tight longitudinal bulkhead, b may be taken as 2/3 of that
indicated in 5C-1-5/Figure 1.
For cL/b > 12, no shear lag effects need to be considered.
The effective sectional areas of deck, inner bottom and bottom longitudinals are to be reduced by
the same ratio, 2Be/B, for calculating SMe.
Alternatively, the hull girder ultimate strength can be determined in accordance with Appendix
5C-1-A5 “Guide for Hull Girder Ultimate Strength Assessment of Oil Carriers”.

FIGURE 1
(1995)

B/2

A.P. cL F.P.

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 5 Total Strength Assessment 5C-1-5

7 Fatigue Life (1995)

7.1 General
An analysis is to be made of the fatigue strength of welded joints and details in highly stressed areas,
especially where higher strength steel is used. Special attention is to be given to structural notches, cutouts
and bracket toes, and also to abrupt changes of structural sections. A simplified assessment of the fatigue
strength of structural details may be accepted when carried out in accordance with Appendix 5C-1-A1.
The following subparagraphs are intended to emphasize the main points and to outline procedures where
refined spectral analysis techniques are used to establish fatigue strength.
7.1.1 Workmanship
As most fatigue data available were experimentally developed under controlled laboratory conditions,
consideration is to be given to the workmanship expected during construction.
7.1.2 Fatigue Data
In the selection of S-N curves and the associated stress concentration factors, attention is to be
paid to the background of all design data and its validity for the details being considered. In this regard,
recognized design data, such as those by AWS (American Welding Society), API (American
Petroleum Institute), and DEN (Department of Energy), should be considered. Sample fatigue data
and their applications are shown in Appendix 5C-1-A1 “Guide for Fatigue Strength Assessment of
Tankers”.
If other fatigue data are to be used, the background and supporting data are to be submitted for review.
In this regard, clarification is required whether or not the stress concentration due to the weld
profile, certain structural configurations and also the heat effects are accounted for in the proposed
S-N curve. Consideration is also to be given to the additional stress concentrations.
7.1.3 Total Stress Range
For determining total stress ranges, the fluctuating stress components resulting from the load
combinations specified in 5C-1-A1/7.5 are to be considered.
7.1.4 Design Consideration
In design, consideration is to be given to the minimization of structural notches and stress
concentrations. Areas subject to highly concentrated forces are to be properly configured and
stiffened to dissipate the concentrated loads. See also 5C-1-4/1.5.

7.3 Procedures
The analysis of fatigue strength for a welded structural joint/detail may be performed in accordance with
the following procedures.
7.3.1 Step 1 – Classification of Various Critical Locations
The class designations and associated load patterns are given in 5C-1-A1/Table 1
7.3.2 Step 2 – Permissible Stress Range Approach
Where deemed appropriate, the total applied stress range of the structural details classified in Step
1 may be checked against the permissible stress ranges as shown in Appendix 5C-1-A1.
7.3.3 Step 3 – Refined Analysis
Refined analyses are to be performed, as outlined in 5C-1-5/7.3.3(a) or 5C-1-5/7.3.3(b) below, for
the structural details for which the total applied stress ranges obtained from Step 2 are greater than
the permissible stress ranges, or for which the fatigue characteristics are not covered by the
classified details and the associated S-N curves.
The fatigue life of structures is generally not to be less than 20 years, unless otherwise specified.
7.3.3(a) Spectral analysis. Alternatively, a spectral analysis may be performed, as outlined in
5C-1-5/7.5 below, to directly calculate fatigue lives for the structural details in question.

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 5 Total Strength Assessment 5C-1-5

7.3.3(b) Refined fatigue data. For structural details which are not covered by the detail
classifications, proposed S-N curves and the associated SCFs, when applicable, may be submitted
for consideration. In this regard, sufficient supporting data and background are also to be submitted
for review. The refined SCFs may be determined by finite element analyses.

7.5 Spectral Analysis

Where the option in 5C-1-5/7.3.3(a) is exercised, a spectral analysis is to be performed in accordance with
the following guidelines.
7.5.1 Representative Loading Patterns
Several representative loading patterns are to be considered to cover the worst scenarios anticipated
for the design service life of the vessel with respect to hull girder local loads.
7.5.2 Environmental Representation
Instead of the design wave loads specified in Section 5C-1-3, a wave scatter diagram (such as
Walden’s Data) is to be employed to simulate a representative distribution of all of the wave
conditions expected for the design service life of the vessel. In general, the wave data is to cover a
time period of not less than 20 years. The probability of occurrence for each combination of
significant wave height and mean period of the representative wave scatter diagram is to be
weighted, based on the transit time of the vessel at each wave environment within anticipated
shipping routes. The representative environment (the wave scatter diagram) is not to be taken less
severe than North Atlantic Ocean in terms of fatigue damage.
7.5.3 Calculation of Wave Load RAOs
The wave load RAOs with respect to the wave-induced bending moments, shear forces, motions,
accelerations and hydrodynamic pressures can then be predicted by ship motion calculation for a
selected representative loading condition.
7.5.4 Generation of Stress Spectrum
The stress spectrum for each critical structural detail (spot) may be generated by performing a
structural analysis, accounting for all of the wave loads separately for each individual wave group.
For this purpose, the 3D structural model and 2D models specified in 5C-1-5/9 may be used for
determining structural responses. The additional secondary and tertiary stresses are also to be
considered.
7.5.5 Cumulative Fatigue Damage and Fatigue Life
Based on the stress spectrum and wave scatter diagram established above, the cumulative fatigue
damage and the corresponding fatigue life can be estimated by the Palmgren-Miner linear damage rule.

9 Calculation of Structural Responses (1995)

9.1 Methods of Approach and Analysis Procedures (1997)

Maximum stresses in the structure are to be determined by performing structural analyses, as outlined
below. Guidelines on structural idealization, load application and structural analysis are given in ABS
Guidance for Finite Element Analysis of Tanker Structures.
In general, the strength assessment is to be focused on the results obtained from structures in the mid hold
of a three hold length model. However, the deck transverse, the side transverse, the vertical web on
longitudinal bulkheads, the horizontal girder and the vertical web on transverse bulkheads and the cross tie
are to be assessed using the end holds of a three hold length model as well.

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 5 Total Strength Assessment 5C-1-5

9.3 3D Finite Element Models (1995)

A simplified three-dimensional finite element model, representing usually three bays of tanks within 0.4L
amidships, is required to determine the load distribution in the structure.
The same 3D model may be used for hull structures beyond 0.4L amidships with modifications to the
structural properties and the applied loads, provided that the structural configurations are considered as
representative of the location under consideration.

9.5 2D Finite Element Models (1995)

Two-dimensional fine mesh finite element models are required to determine the stress distribution in major
supporting structures, particularly at intersections of two or more structural members.

9.7 Local Structural Models (1995)

A 3D fine mesh model is to be used to examine stress concentrations, such as at intersections of longitudinals
with transverses and at cut outs.

9.9 Load Cases (1995)

When performing structural analysis, the eight combined load cases specified in 5C-1-3/9.1 are to be
considered. In general, the structural responses for the still-water conditions are to be calculated separately
to establish reference points for assessing the wave-induced responses. Additional load cases may be
required for special loading patterns and unusual design functions, such as sloshing loads, as specified in
5C-1-3/11. Additional load cases may also be required for hull structures beyond the region of 0.4L
amidships.

11 Critical Areas (1 July 2005)

The fatigue strength of the following critical areas is to be verified by fine mesh finite element models built
in accordance with Appendix 5C-1-A1:
• Typical deck longitudinal connection at transverse bulkhead
• Typical bottom and inner bottom longitudinal connections at transverse bulkhead and the 1st web
frames adjacent to transverse bulkhead
• Typical side shell longitudinal connections at transverse bulkhead and the 1st web frames adjacent to
transverse bulkhead
• Critical areas of transverse web frames in 5C-1-5/Figure 2
• Critical areas of horizontal girders on transverse bulkhead in 5C-1-5/Figure 3
• Critical areas of buttress structure in 5C-1-5/Figure 4
The mesh size in way of high stress concentration is to be of plate thickness dimension (t). The element
stress intensity at half plate thickness dimension (t/2) away from the weld toe is to satisfy the following
stress limit:
fi ≤ fu
where
fi = stress intensity

= ( f L2 + f T2 − fL fT + 3 f LT
2 1/2
) N/cm2 (kgf/cm2, lbf/in2)
fL = calculated total in-plane element stress in the longitudinal direction
fT = calculated total in-plane element stress in the transverse/vertical direction
fLT = calculated total in-plane element shear stress
fu = the minimum tensile strength of the material

132 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 5 Total Strength Assessment 5C-1-5

FIGURE 2
Critical Areas in Transverse Web Frame (1 July 2005)

FIGURE 3
Critical Areas in Horizontal Girder on Transverse Bulkhead (1 July 2005)

FIGURE 4
Critical Areas of Buttress Structure (1 July 2005)

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 133
PART Section 6: Hull Structure Beyond 0.4L Amidships

5C
CHAPTER 1 Vessels Intended to Carry Oil in Bulk (150 meters
(492 feet) or more in Length)

SECTION 6 Hull Structure Beyond 0.4L Amidships

1 General Requirements

1.1 General
The structural configurations, stiffening systems and design scantlings of the hull structures located beyond
0.4L amidships, including the forebody, aft end and machinery spaces, are to be in compliance with
5C-2-2/17 and this Section of the Rules.

1.3 Structures within the Cargo Space Length (2002)

The scantlings of longitudinal structural members and elements in way of cargo spaces beyond the 0.4L
amidships may be gradually reduced toward 0.125L from the ends, provided that the hull girder section
modulus complies with 3-2-1/3.7.1 and that the strength of the structure satisfies the material yielding,
buckling and ultimate strength criteria specified in 5C-1-5/3 and 5C-1-5/5.
The scantlings of main supporting members in way of the cargo space length beyond 0.4L amidships are to
comply with the requirements of 5C-1-4/11. Where the structural configuration is different from that
amidships due to the hull form of the vessel, additional evaluation is to be performed. The structural
evaluation using the actual configuration is to be carried out to ensure that the arrangement of openings
necessary for access (5C-1-1/5.21), ventilation (5C-1-1/5.25), fabrication, etc. is satisfactory.

3 Forebody Side Shell Structure (2000)

In addition to the requirements specified in other relevant sections of the Rules, the scantlings of the
structure forward of 0.4L amidships are also to satisfy the requirements in 5C-1-6/3.1, 5C-1-6/3.3 and
5C-1-6/3.5 below.
The nominal design corrosion values in the forepeak tank may be taken as 1.5 mm in determining design
scantlings.

3.1 Side shell Plating (2002)

3.1.1 Plating Forward of Forepeak Bulkhead
The net thickness of the side shell plating forward of the forepeak bulkhead is to be not less than
t1, t2 and t3, specified below.

t1 = 0.73s(k1 p/f1)1/2 in mm (in.)

t2 = 0.73s(k2 p/f2)1/2 in mm (in.)
t3 = 0.73sk(k3k4 pb /f3)1/2 in mm (in.) for side shell and bow plating above
LWL in the region from the forward
end to the forepeak bulkhead

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 6 Hull Structure Beyond 0.4L Amidships 5C-1-6

where
s = spacing of stiffeners, in mm (in.)
k1 = 0.342 for longitudinally and 0.50k2 for transversely stiffened plating

k2 = 0.50k2 for longitudinally and 0.342 for transversely stiffened plating

k3 = 0.50
k4 = 0.74

k = (3.075(α)1/2 – 2.077)/(α + 0.272), (1 ≤ α ≤ 2)

= 1.0 (α > 2)
α = aspect ratio of the panel (longer edge/shorter edge)
f1 = 0.65 Sm fy, in N/cm2 (kgf/cm2, lbf/in2) in the longitudinal direction

f2 = 0.85 Sm fy, in N/cm2 (kgf/cm2, lbf/in2) in the transverse (vertical) direction

f3 = 0.85 Sm fy, in N/cm2 (kgf/cm2, lbf/in2)

p = nominal pressure |pi – pe|, in N/cm2 (kgf/cm2, lbf/in2), as specified in

5C-1-3/Table 3, at the upper turn of bilge level amidships with the following
modifications:
i) Ati is to be calculated at the forward or aft end of the tank, whichever
is greater
ii) Ae is to be calculated at the center of the panel in accordance with
5C-1-3/5.5.3, using L.C.7 with kfo = 1.0 and xo located amidships
iii) Be is to be calculated at 0.05L from the FP in accordance with
5C-1-3/5.5 (ps + ku pd, full draft, heading angle = 0, ku = 1.1)
pb = the maximum bow pressure = kupbij
ku = 1.1
pbij = nominal bow pressure, as specified in 5C-1-3/13.1.1, at the lowest point of
the panel, in N/cm2 (kgf/cm2, lbf/in2)
Sm and fy, as defined in 5C-1-4/7.3.1.

3.1.2 Plating between Forepeak Bulkhead and 0.125L from FP

Aft of the forepeak bulkhead and forward of 0.125L from the FP, the side shell plating is to be not
less than as given in 5C-1-6/3.1.1 with Be calculated at 0.125L and the following permissible stress.
f1 = permissible bending stress in the longitudinal direction, in N/cm2 (kgf/cm2,
lbf/in2)
= 0.50Sm fy , for L ≥ 190 m (623 ft)
= [0.50 + 0.10(190 – L)/40] Sm fy , for L < 190 m (623 ft)
2 2 2
f2 = 0.80Sm fy , in N/cm (kgf/cm , lbf/in ), in the transverse (vertical) direction
3.1.3 Plating between 0.3L and 0.125L from FP
The net thickness of the side shell plating between 0.3L and 0.125L from the FP is to be determined
from the equations in 5C-1-4/5.3 and 5C-1-6/3.1.2 above with Be calculated at the longitudinal
location under consideration. Between 0.3L and 0.25L from the FP, the internal pressure need not
be greater than that obtained amidships. The permissible stress f1 between 0.3L and 0.2L from the
FP is to be obtained by linear interpolation between midship region (5C-1-4/9.1) and the permissible
stress f1, as specified in 5C-1-6/3.1.2.

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 6 Hull Structure Beyond 0.4L Amidships 5C-1-6

3.3 Side Frames and Longitudinals

3.3.1 Side Frames and Longitudinals Forward of 0.3L from FP
The net section modulus of side longitudinals and frames in association with the effective plating
to which they are attached is to be not less than that obtained from the following equation:
SM = M/fbi in cm3 (in3)

M = 1000psl2/k in N-cm (kgf-cm, lbf-in)

where
k = 12 (12, 83.33)
p = nominal pressure |pi – pe|, in N/cm2 (kgf/cm2, lbf/in2), as specified in
5C-1-3/Table 3 with the following modifications:
i) Ati is to be calculated at the forward or aft end of the tank, whichever
is greater. Between 0.3L and 0.25L aft of the FP, the internal
pressure need not be greater than that obtained amidships.
ii) Ae is to be calculated at the center of the panel in accordance with
5C-1-3/5.5.3 using L.C.7 with kfo = 1.0 and xo located amidships.
iii) Be is to be calculated at the center of the panel in accordance with
5C-1-3/5.5 (ps + ku pd , full draft, heading angle = 0, ku = 1.1), with
the distribution of pd, as shown in 5C-1-6/Figure 1, at the side
longitudinal and frame under consideration.
Longitudinal distribution of pd may be taken as constant from the FP to forepeak bulkhead as per
5C-1-6/3.1.1 and from 0.125L to the forepeak bulkhead as per 5C-1-6/3.1.2. pd is to be calculated
in accordance with 5C-1-3/5.5 between 0.3L and 0.125L from the FP as per 5C-1-6/3.1.3.
fbi = 0.80 Sm fy in N/cm2 (kgf/cm2, lbf/in2), for longitudinals between 0.125L and
0.2L from the FP
= 0.85 Sm fy in N/cm2 (kgf/cm2, lbf/in2), for longitudinals forward 0.125L from
the FP
= 0.85 Sm fy in N/cm2 (kgf/cm2, lbf/in2), for vertical frames (other than hold
frames)
Between 0.3L and 0.2L from the FP, the permissible stress is to be obtained by linear interpolation
between midship region and 0.80 Sm fy
Sm and fy are as defined in 5C-1-4/7.3.1.

s and l are as defined in 5C-1-4/7.5.

For side longitudinal/stiffener in the region forward of 0.0125L from the FP and above LWL, the
section modulus is not to be less than obtained from the above equation based on p = pb , fb = 0.95
Sm fy and k = 16 (16, 111.1), where pb is as defined in 5C-1-6/3.1 above.

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 6 Hull Structure Beyond 0.4L Amidships 5C-1-6

FIGURE 1
Transverse Distribution of pd (2000)

Freeboard Deck

Pd1 LWL

Bilge Radius
Amidships

Pd2

L
C

3.5 Side Transverses and Stringers in Forebody (2002)

The requirements of the subparagraphs below apply to the region forward of the cargo spaces where single
side skin construction is used.
3.5.1 Section Modulus
The net section modulus of side transverse and stringer in association with the effective side shell
plating is not to be less than obtained from the following equation:
SM = M/fb in cm3 (in3)
3.5.1(a) Longitudinally Framed Side Shell
For side stringer
M = 1000c1c2 pslt ls /k in N-cm (kgf-cm, lbf-in)
For side transverse, M is not to be less than M1 or M2, whichever is greater

M1 = 1000c3 ps l 2t (1.0 – c4φ)/k in N-cm (kgf-cm, lbf-in)

M2 = 850p1s l 2t1 /k in N-cm (kgf-cm, lbf-in)

where
k = 0.12 (0.12, 0.446)
c1 = 0.125 + 0.875φ, but not less than 0.3
Coefficients c2, c3 and c4 are given in the tables below.

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 6 Hull Structure Beyond 0.4L Amidships 5C-1-6

Coefficient c2
Number of Side Stringers No Stringer One Stringer More than one
Between Platforms (flats) Stringer
Top Stringer 0.70
Stringers Between Top and 0.0 0.90 0.75
Lowest Stringers
Lowest Stringer 0.80

Coefficient c3
Number of Side Stringers No Stringer One Stringer More than one
Between Platforms (flats) Stringer
Transverse above Top 0.55 0.55
Stringer
Transverse Between Top 0.85 — 0.64
and Lowest Stringers
Transverse Below Lowest 0.68 0.68
Stringer

Coefficient c4
Number of Side Stringers No Stringer One Stringer More than one
Between Platforms (flats) Stringer

Transverses 0.0 0.75 0.80

p = nominal pressure, |pi – pe|, in kN/m2 (tf/m2, Ltf/ft2), over the side transverses
using the same load cases as specified in 5C-1-3/Table 3 for side transverses
with the following modifications.
i) Ae is to be considered for case “a” and calculated in accordance with
5C-1-3/5.5.3 using L.C.7 with kfo = 1.0 and xo located amidships
ii) Be is to be calculated in accordance with 5C-1-3/5.5 (ps + ku pd , full
draft, heading angle = 0, ku = 1) with the distribution of pd as shown
in 5C-1-6/Figure 1.
Bi, Ae and Be may be taken at the center of the side shell panel under
consideration.
p1 = nominal pressure, |pi – pe|, in kN/m2 (tf/m2, Ltf/ft2), using the same load
cases as specified in 5C-1-3/Table 3 for side transverses with the following
modifications.
i) Ae is to be considered for case “a” and calculated in accordance with
5C-1-3/5.5.3 using L.C.7 with kfo = 1.0 and xo located amidships
ii) Be is to be calculated in accordance with 5C-1-3/5.5 (ps + ku pd , full
draft, heading angle = 0, ku = 1) with the distribution of pd as shown
in 5C-1-6/Figure 1.
Bi, Ae and Be, calculated at the midspan ls1 (between side stringers or
between side stringer and platform, flat as shown in 5C-1-6/Figure 2) of the
side transverse under consideration.
For side transverses
s = sum of half distances, in m (ft), between side transverse under consideration
and adjacent side transverses or transverse bulkhead

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 6 Hull Structure Beyond 0.4L Amidships 5C-1-6

For side stringers

s = 0.45ls

φ = 1/(1 + α)
α = 1.33(It /Is)(ls/lt)3
It = moment of inertia, in cm4 (in4) (with effective side plating), of side transverse.
It is to be taken as an average of those at the middle of each span lt1 between
side stringers or side stringer and platform (flat), clear of the bracket
Is = moment of inertia, in cm4 (in4) (with effective side plating), of side stringer
at the middle of the span ls, clear of the bracket
lt, ls = spans, in m (ft), of the side transverse (lt) and side girder (ls) under
consideration, as shown in 5C-1-6/Figure 2
lt1 = span, in m (ft), of side transverse under consideration between stringers, or
stringer and platform (flat), as shown in 5C-1-6/Figure 2b
When calculating α, if more than one side transverse or stringer is fitted and they are not identical,
average values of It and Is within side shell panel (panel between transverse bulkheads and platforms,
flats) are to be used.
fb = permissible bending stress in N/cm2 (kgf/cm2, lbf/in2)
= 0.75 Sm fy
Sm and fy are as defined in 5C-1-4/7.3.1.
The bending moment for side transverse below stringer (or below the platform if no stringer is
fitted) is not to be less than 80% of that for side transverse above stringer (or above platform if no
stringer is fitted).
3.5.1(b) Transversely Framed Side Shell
For side transverse
M = 1000c1psltls /k in N-cm (kgf-cm, lbf-in)
For side stringer, M is not to be less than M1 or M2, whichever is greater

M1 = 1000c2 ps l 2s (1.0 – c3φ1)/k in N-cm (kgf-cm, lbf-in)

M2 = 1100p1sls1/k in N-cm (kgf-cm, lbf-in)

where
k = 0.12 (0.12, 0.446)
c1 = 0.10 + 0.7φ1, but not to be taken less than 0.085
If no side transverses are fitted between transverse bulkheads
c2 = 1.1
c3 = 0
If side transverses are fitted between transverse bulkheads
c2 = 0.8
c3 = 0.8

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 6 Hull Structure Beyond 0.4L Amidships 5C-1-6

p = nominal pressure, |pi – pe|, in kN/m2 (tf/m2, Ltf/ft2), over the side stringers
using the same load cases as specified in 5C-1-3/Table 3 for side transverses
in lower wing tank. Ati, Ae and Be may be taken at the center of the side shell
panel under consideration with the following modifications:
i) Ae is to be calculated in accordance with 5C-1-3/5.5.3 using L.C.7
with kfo = 1.0 and xo located amidships
ii) Be is to be calculated in accordance with 5C-1-3/5.5 (ps + ku pd , full
draft, heading angle = 0, ku = 1) with the distribution of pd as shown
in 5C-1-6/Figure 1.
p1 = nominal pressure, |pi – pe|, in kN/m2 (tf/m2, Ltf/ft2), using the same load
cases as specified in 5C-1-3/Table 3 for side transverses in lower wing tank,
with Ati, Ae and Be calculated at the midspan ls1 (between side transverses or
between side transverse and transverse bulkhead, as shown in 5C-1-6/Figure
2a) of the side stringer under consideration, with the following
modifications:
i) Ae is to be calculated in accordance with 5C-1-3/5.5.3 using L.C.7
with kfo = 1.0 and xo located amidships
ii) Be is to be calculated in accordance with 5C-1-3/5.5 (ps + ku pd , full
draft, heading angle = 0, ku = 1) with the distribution of pd as shown
in 5C-1-6/Figure 1.
For side stringers
s = sum of half distances, in m (ft), between side stringer under consideration
and adjacent side stringers or platforms (flats)
For side transverses
s = 0.45lt

φ1 = α/(1 + α)
ls1 = span, in m (ft), of the side stringer under consideration between side
transverses or side transverse and transverse bulkhead, as shown in
5C-1-6/Figure 2a
fb = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.75 Sm fy
Sm and fy are as defined in 5C-1-4/7.3.1.

lt, ls and α are as defined in 5C-1-6/3.5.1(a) above.

3.5.2 Sectional Area of Web

The net sectional area of the web portion of the side transverse and side stringer is not to be less
than obtained from the following equation:
A = F/fs
3.5.2(a) Longitudinally Framed Side Shell
For side stringer
F = 1000kc1pls in N (kgf, lbf)

140 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 6 Hull Structure Beyond 0.4L Amidships 5C-1-6

For side transverse, F is not to be less than F1 or F2, whichever is greater

F1 = 850kc2pls(1.0 – c3φ – 2he /l) N (kgf, lbf)

F2 = 1700kc2p1s(0.5l1 – he) N (kgf, lbf)

where
k = 0.5 (0.5, 1.12)
Coefficients c1, c2 and c3 are given in the tables below.

Coefficient c1
Number of Side Stringers No Stringer One Stringer More than one
Between Platforms (flats) Stringer
Stringers 0.0 0.52 0.40

Coefficient c2
Number of Side Stringers No Stringer One Stringer More than one
Between Platforms (flats) Stringer
Transverses Above Top 0.9 0.9
Stringer
Transverse Between Top 1.0 — 0.95
and Lowest Stringers
Transverse Below Lowest 1.0 1.0
Stringer

Coefficient c3
Number of Side Stringers No Stringer One Stringer More than one
Between Platforms (flats) Stringer
Transverses 0.0 0.5 0.6

l = span, in m (ft), of the side transverse under consideration between platforms

(flats), as shown in 5C-1-6/Figure 2b
l1 = span, in m (ft), of the side transverse under consideration between side
stringers or side stringer and platform (flat), as shown in 5C-1-6/Figure 2b
he = length, in m (ft), of the end bracket of the side transverse, as shown in
5C-1-6/Figure 2b
To obtain F1, he is equal to the length of the end bracket at the end of span l of side transverse, as
shown in 5C-1-6/Figure 2b.
To obtain F2, he is equal to the length of the end bracket at the end of span l1 of side transverse, as
shown in 5C-1-6/Figure 2b.
fs = permissible shear stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.45 Sm fy
Sm and fy are as defined in 5C-1-4/7.3.1.

p, p1, φ and s are as defined in 5C-1-6/3.5.1(a) above.

The shear force for the side transverse below the lowest stringer (or below the platform if no
stringer is fitted), is not to be less than 110% of that for the side transverse above the top stringer
(or above the platform if no stringer is fitted).

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 6 Hull Structure Beyond 0.4L Amidships 5C-1-6

3.5.2(b) Transversely Framed Side Shell

For side transverse
F = 850kc1pls in N (kgf, lbf)
For side stringer, F is not to be less than F1 or F2, whichever is greater.

F1 = 1000kpls(1.0 – 0.6φ1 – 2he /l) in N (kgf, lbf)

F2 = 2000kp1s(0.5l1 – he) in N (kgf, lbf)

where
k = 0.5 (0.5, 1.12)
c1 = 0.1 + 0.7φ1, but not to be taken less than 0.2

l = span, in m (ft), of the side stringer under consideration between transverse

bulkheads, as shown in 5C-1-6/Figure 2a
l1 = span, in m (ft), of the side stringer under consideration between side
transverses or side transverse and bulkhead, as shown in 5C-1-6/Figure 2a
he = length, in m (ft), of the end bracket of the side stringer under consideration,
as shown in 5C-1-6/Figure 2a
To obtain F1, he is equal to the length of the end bracket at the end of span l of the side stringer, as
shown in 5C-1-6/Figure 2a.
To obtain F2, he is equal to the length of the end bracket at the end of span l1 of the side stringer,
as shown in 5C-1-6/Figure 2a.
fs = permissible shear stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.45 Sm fy
Sm and fy are as defined in 5C-1-4/7.3.1.

p, p1, φ1 and s are as defined in 5C-1-6/3.5.1(a) above.

3.5.3 Depth of Transverse/Stringer

The depths of side transverses and stringers, dw, are neither to be less than obtained from the
following equations nor to be less than 2.5 times the depth of the slots, respectively.
3.5.3(a) Longitudinally Framed Shell
For side transverse
If side stringer is fitted between platforms (flats)
dw = (0.08 + 0.80α)lt for α ≤ 0.05

= (0.116 + 0.084α)lt for α > 0.05

and need not be greater than 0.2lt

If no side stringer is fitted between platforms (flats), dw is not to be less than 0.2lt or 0.06D,
whichever is greater.
For side stringer
dw = (0.42 – 0.9α)ls for α ≤ 0.2

= (0.244 – 0.0207α)ls for α > 0.2

α is not to be taken greater than 8.0 to determine the depth of the side stringer.

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 6 Hull Structure Beyond 0.4L Amidships 5C-1-6

lt, ls and α are as defined in 5C-1-6/3.5.1(a) above.

D is as defined in 3-1-1/7.
3.5.3(b) Transversely Framed Side Shell
For side stringer
If side transverse is fitted between transverse bulkheads
dw = (0.08 + 0.80α1)ls for α1 ≤ 0.05

= (0.116 + 0.084α1)ls for α1 > 0.05

and need not be greater than 0.2ls

If no side transverse is fitted between transverse bulkheads
dw = 0.2ls
For side transverse
dw = (0.277 – 0.385α1)lt for α1 ≤ 0.2

= (0.204 – 0.205α1)lt for α1 > 0.2

α1 is not to be taken greater than 7.5 to determine the depth of the side transverse
where
α1 = 1/α
lt, ls and α are as defined in 5C-1-6/3.5.1(a) above.

3.5.4 Thickness
The net thickness of side transverse and stringer is not to be less than 9.5 mm (0.374 in.)

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 6 Hull Structure Beyond 0.4L Amidships 5C-1-6

FIGURE 2
Definition of Spans (2000)

he

he h
e SIDE
SHEL
L
he
ls1
ls

ls1

l1

TRANSV. BHD
TRANSV. BHD

a. Stringer

PLATFORM FLAT

he

l1
lt1
he

he lt l

lt1
SIDE SHELL

l1

he
PLATFORM FLAT

b. Transverse

5 Transition Zone (2000)

In the transition zone between the forepeak and the No. 1 cargo tank region, due consideration is to be
given to the proper tapering of major longitudinal members within the forepeak such as flats, decks,
horizontal ring frames or side stringers aft into the cargo hold. Where such structure is in line with
longitudinal members aft of the forward cargo tank bulkhead, this may be effected by fitting of large
tapering brackets. These brackets are to have a taper of 4:1.

144 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 6 Hull Structure Beyond 0.4L Amidships 5C-1-6

7 Forebody Strengthening for Slamming (2000)

Where the hull structure is subject to slamming, as specified in 5C-1-3/13, proper strengthening will be
required as outlined below. For strengthening to account for bottom slamming, the requirements of this
subsection apply to vessels with a heavy ballast draft forward of less than 0.04L and greater than 0.025L.
Vessels with heavy ballast draft forward equal to or less than 0.025L will be subject to special consideration.

7.1 Bottom Slamming

7.1.1 Bottom Plating
When bottom slamming, as specified in 5C-1-3/13, is considered, the bottom structure in the
region of the flat of bottom forward of 0.25L measured from the FP is to be in compliance with the
following requirement.
The net thickness of the flat of bottom plating forward of 0.25L measured from the FP is not to be
less than t obtained from the following equation:
t = 0.73s(k2 k3 ps/f)1/2 in mm (in.)
where
s = spacing of longitudinal or transverse stiffeners, in mm (in.)
k2 = 0.5 k2 for longitudinally stiffened plating
k3 = 0.74

k = (3.075 (α)1/2 – 2.077)/(α + 0.272), (1 ≤ α ≤ 2)

= 1.0 (α > 2)
α = aspect ratio of the panel (longer edge/shorter edge)
ps = the design slamming pressure = ku psi
For determination of t, the pressure ps is to be taken at the center of the supported panel.
psi = nominal bottom slamming pressure, as specified in 5C-1-3/13.3.1, in N/cm2
(kgf/cm2, lbf/in2)
ku = slamming load factor = 1.1
The maximum nominal bottom slamming pressure occurring along the vessel is to be applied to
the bottom plating between the foremost extent of the flat of bottom and 0.125L from the FP. The
pressure beyond this region may be gradually tapered to the longitudinal location where the
nominal slamming pressure is calculated as zero.
f = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.85 Sm fy
Sm and fy are as defined in 5C-1-4/7.3.1.

7.1.2 Bottom Longitudinals and Stiffeners

The section modulus of the stiffener, including the associated effective plating on the flat of bottom
forward of 0.25L measured from the FP, is not to be less than obtained from the following equation:
SM = M/fb in cm3 (in3)

M = 1000pssl2/k in N-cm (kgf-cm, lbf-in)

where
k = 16 (16, 111.1)
ps = the design slamming pressure = ku psi

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 6 Hull Structure Beyond 0.4L Amidships 5C-1-6

For determination of M, the pressure ps is to be taken at the midpoint of the span l.

psi = nominal bottom slamming pressure, as specified in 5C-1-3/13.3.1, in N/cm2
(kgf/cm2, lbf/in2)
ku = slamming load factor = 1.1
The maximum nominal bottom slamming pressure occurring along the vessel is to be applied to
the bottom stiffeners between the foremost extent of the flat of bottom and 0.125L from the FP.
The pressure beyond this region may be gradually tapered to the longitudinal location where the
nominal slamming pressure is calculated as zero.
s = spacing of longitudinal or transverse stiffeners, in mm (in.)
l = the unsupported span of the stiffener, in m (ft)
fb = 0.9Sm fy for transverse and longitudinal stiffeners in the region forward of
0.125L measured from the FP
= 0.8Sm fy for longitudinal stiffeners in the region between 0.125L and 0.25L
measured from the FP
The effective breadth of plating be is as defined in 5C-1-4/7.5.
Struts connecting the bottom and inner bottom longitudinals are not to be fitted.
7.1.3 Bottom Floors
The arrangements and scantlings of floors are to be adequate for bottom slamming loads, as
specified in 5C-1-3/13.
The spacing of floors forward of amidships need not be less than the spacing amidships.

7.3 Bowflare Slamming

When bowflare slamming, as specified in 5C-1-3/13.5, is considered, the side shell structure above the
waterline in the region between 0.0125L and 0.25L from the FP is to be in compliance with the following
requirements.
7.3.1 Side Shell Plating
The net thickness of the side shell plating between 0.0125L and 0.25L from the FP is not to be less
than t1 or t2, whichever is greater, obtained from the following equations:
t1= 0.73s(k1 ps/f1)1/2 in mm (in.)

t2 = 0.73s(k2 ps/f2)1/2 in mm (in.)

where
ps = the maximum slamming pressure = ku pij
pij = nominal bowflare slamming pressure, as specified in 5C-1-3/13.5.1, at the
lowest point of the panel, in N/cm2 (kgf/cm2, lbf/in2)
ku = slamming load factor = 1.1
f1 = 0.85 Sm fy for side shell plating forward of 0.125L from the FP, in N/cm2
(kgf/cm2, lbf/in2)
= 0.75 Sm fy for side shell plating in the region between 0.125L and 0.25L from
the FP, in N/cm2 (kgf/cm2, lbf/in2)
f2 = 0.85 Sm fy , in N/cm2 (kgf/cm2, lbf/in2)
k1 = 0.342 for longitudinally stiffened plating
= 0.5 for transversely stiffened plating

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 6 Hull Structure Beyond 0.4L Amidships 5C-1-6

k2 = 0.5 for longitudinally stiffened plating

= 0.342 for transversely stiffened plating
s, Sm and fy are as defined in 5C-1-6/7.1.1 above.

7.3.2 Side Longitudinals and Stiffeners

The section modulus of the stiffener, including the associated effective plating, is not to be less
than obtained from the following equation:
SM = M/fb in cm3 (in3)

M = 1000pssl2/k in N-cm (kgf-cm, lbf-in)

where
k = 16 (16, 111.1)
l = unsupported span of the stiffener, in m (ft)
ps = the maximum slamming pressure, in N/cm2 (kgf/cm2, lbf/in2), as defined in
5C-1-6/7.3.1, at the midpoint of the span l
s and fb are as defined in 5C-1-6/7.1 above.
The effective breadth of plating, be, is as defined in 5C-1-4/7.5.

7.3.3 Side Transverses and Side Stringers (1 July 2008)

For the region between 0.0125L and 0.25L from the FP, the net section modulus and sectional area
requirements for side transverses and side stringers in 5C-1-6/3.5 are to be met with the bow flare
slamming pressure as specified in 5C-1-3/13.5.1 and with the permissible bending stress of fb =
0.64Sm fy and the permissible shear stress of fs = 0.38Sm fy.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 147
PART Section 7: Cargo Oil and Associated Systems

5C
CHAPTER 1 Vessels Intended to Carry Oil in Bulk (150 meters
(492 feet) or more in Length)

SECTION 7 Cargo Oil and Associated Systems

1 General

1.1 Application
1.1.1 Flash Point
The provisions of Part 5C, Chapter 1, Section 7 (referred to as Section 5C-1-7) apply primarily to
vessels intended to carry in bulk oil or petroleum products having a flash point of 60°C (140°F),
closed cup test, or below. Vessels intended to carry in bulk only oil or petroleum products having
a flash point exceeding 60°C (140°F) may comply with the provisions of 5C-1-7/1.9 hereunder.
1.1.2 Class Notations
The provisions of Section 5C-1-7 form a part of the necessary condition for assigning the classification
notation Oil Carrier. For vessels intended to carry in bulk only oil or petroleum products having a
flash point exceeding 60°C (140°), the notation Fuel Oil Carrier is to be assigned. See 5C-1-1/1.1
and 5C-2-1/1.1.
Where requested by the owner, vessels in which all cargo piping and valve control piping are
located above the double bottom will be assigned the notation CPP (Cargo Piping Protected).
CPP is not a condition of classification. See 5C-1-7/3.3.4.
Where a cargo vapor emission control system is installed, the provisions of 5C-1-7/21 are applicable.
Systems satisfying these provisions will be assigned with the notation VEC. Systems satisfying
the additional provisions of 5C-1-7/21.19 for lightering operation will be assigned with the notation
VEC-L.
1.1.3 AMS Notation
The provisions of Part 4, pertaining to assigning the machinery class notation AMS, are applicable
to oil carriers and fuel oil carriers in addition to the provisions of this section. See 4-1-1/1.5.
1.1.4 Combination Carriers
Combination carriers when engaged in the carriage of oil are to comply with these requirements.
In general, combination carriers are not permitted to carry oil and bulk cargoes simultaneously.

1.3 Definitions
1.3.1 Crude Oil Carrier
Crude Oil Carrier is a vessel engaged in the trade of carrying crude oil. Crude oil means any
liquid hydrocarbon mixture occurring naturally in the earth whether or not treated to render it
suitable for transportation and includes:
• Crude oil from which certain distillate fractions may have been removed; and
• Crude oil to which certain distillate fractions may have been added.
1.3.2 Product Carrier
Product Carrier is a vessel engaged in the trade of carrying oil other than crude oil.

148 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 7 Cargo Oil and Associated Systems 5C-1-7

1.3.3 Oil Carrier

As used throughout the Rules, Oil Carrier means any vessel engaged in the trade of carrying
crude oil or other oil products having a flash point of 60°C (140°F) or less.
1.3.4 Fuel Oil Carrier
As used throughout the Rules, Fuel Oil Carrier means any vessel engaged in the trade of carrying
oil or oil products having a flash point above 60°C (140°F).
1.3.5 Combination Carrier
Combination Carrier is a vessel designed to carry either oil or solid cargoes in bulk.
1.3.6 Segregated Ballast
Segregated Ballast is the ballast water introduced into a tank which is completely separated from
the cargo oil and fuel oil systems and which is permanently allocated to the carriage of ballast or
cargoes other than oil.
1.3.7 Cargo Area
Cargo Area is that part of the vessel that contains cargo tanks, slop tanks and cargo pump rooms
including pump rooms, cofferdams, ballast and void spaces adjacent to cargo tanks and also deck
areas throughout the entire length and breadth of the part of the vessel over the above mentioned
spaces.
1.3.8 Hazardous Areas
Areas where flammable or explosive gases or vapors are normally present or likely to be present
are known as Hazardous Areas. The flammable or explosive atmosphere may be expected to exist
continuously or intermittently. Typically, the cargo area, spaces around cargo tank openings,
spaces around disconnectable cargo oil pipe joints, etc. are to be regarded as hazardous areas. The
word ‘hazardous’, where used in this section, means the presence of a flammable atmosphere. See
5C-1-7/31.5.

1.5 Plans and Data to be Submitted

The following plans and data specific to oil carriers are to be submitted:
Booklet showing standard construction details for piping, see 4-6-1/9.5.
General arrangement showing the location of the cargo pump room, cargo pumps and cargo tanks.
Cargo oil pumping and tank stripping system.
Cargo oil heating system.
Arrangement of cargo pumps, including drives and drive shaft bulkhead gland arrangements.
Cargo pump room ventilation.
Pipe tunnel/duct keel ventilation.
Gas detection systems for cargo pump room and pipe tunnel/duct keel.
Bilge pumping arrangements for cargo pump rooms and cofferdams.
Segregated ballast or ballast system, as applicable.
Cargo tanks venting and gas freeing systems including details of the pressure/vacuum valves.
Inert gas system, including inert gas generating plant, all control and monitoring devices, and inert
gas distribution piping.
Cargo vapor emission control system, see further details in 5C-1-7/21.3.
Crude oil washing system and operational manual.
Oil discharge monitoring and control system and operational manual.

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 7 Cargo Oil and Associated Systems 5C-1-7

Fixed deck foam fire extinguishing system.

Fixed fire extinguishing system for cargo pump room.
Hazardous area plan and electrical equipment data, see 4-8-1/5.3.2.
Other electrical systems and installation, see 4-8-1/5.

1.7 Some General Principles

1.7.1 Basic Requirements
The provisions of Section 5C-1-7 are intended to address flammable and pollution hazards of
cargo oil and are to be read in conjunction with the requirements in Part 5C, Chapter 1 and Part
5C, Chapter 2.
With respect to flammability hazards, these provisions (following the intent of SOLAS) seek to:
• Segregate cargo oil from its ignition sources;
• Reduce the flammability of cargo oil vapor and air mixtures by means of:
Cargo tank inerting,
Effective dispersion of vapor released to the atmosphere, and
Forced ventilation of enclosed spaces such as cargo pump room;
• Observe the safety of electrical equipment in hazardous areas; and
• Provide effective means of extinguishing fires should they break out.
With respect to pollution hazards, these requirements (following the intent of MARPOL Annex I)
seek to:
• Provide segregated ballast;
• Separation of ballast piping from cargo piping, ballast piping from cargo tank and cargo
piping from ballast tanks;
• Provide effective means for cargo tank cleaning;
• Provide means for processing and discharging contaminated waters.
1.7.2 Spaces Adjacent to Cargo Tanks (2012)
Tanks and spaces separated from cargo tanks by a single deck or bulkhead may be contaminated
by cargo oil or vapor due to possible impairment of the common boundary. These tanks and
spaces are therefore, in principle, to be regarded as hazardous spaces. Piping serving or having an
opening into these tanks or spaces is likewise to be regarded as contaminated and, therefore, is not
permitted to enter machinery and other spaces normally containing sources of ignition except that
short lengths of all welded steel pipe may be specially considered. The pipe is to be adequately
secured and is to have minimum wall thickness according to Column E of 4-6-2/Table 4. Fuel oil
bunker tanks adjacent to cargo oil tanks and associated bunker fuel oil piping are specifically
excluded from this consideration.
1.7.3 Piping Passing Through Cargo Tanks
Piping passes through cargo oil tanks, due to possible deterioration or leakage in the pipe or pipe
joints, may lead to contamination of liquid within the piping by cargo oil or vapor. Such piping is
therefore, in principle, not permitted to enter machinery and other spaces normally containing
sources of ignition. Steam systems used for heating cargo oil tanks, and hydraulic systems used
for operating valves located in cargo tanks are specifically excluded from this consideration. See
5C-1-7/9.3 and 5C-1-7/3.5, respectively.

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 7 Cargo Oil and Associated Systems 5C-1-7

1.9 Cargo Oil Having a Flash Point Exceeding 60°C (2004)

1.9.1
For vessels intended to carry in bulk only oil or petroleum products having a flash point exceeding
60°C (140°F), the provisions of Section 5C-1-7 apply only where appropriate. In general, the
provisions addressing flammable hazards of oil and vapor, such as that described in principle in
5C-1-7/1.7, do not apply; only the provisions for oil pollution prevention apply. The following
may be used as guidance for applicability:
i) Cargo oil piping, tank level gauging, venting and heating systems: the provisions of
4-6-4/13 for fuel oil storage and transfer systems may apply in lieu of the provisions in
Section 5C-1-7; however, pollution prevention measures in Section 5C-1-7 are applicable.
Specifically, the following provisions of Section 5C-1-7 are applicable:
• 5C-1-7/3.3.1, except 5C-1-7/3.3.1(c), 5C-1-7/3.3.1(d) and 5C-1-7/3.3.1(e), for cargo
pumps;
• 5C-1-7/3.3.4, except 5C-1-7/3.3.4(e) for cargo piping – pollution prevention measures;
• 5C-1-7/3.5, for remotely operated valves;
• 5C-1-7/11, cargo tank venting, only if pressure/vacuum valve controlled venting is
provided;
• 5C-1-7/11.9, vent outlets from cofferdams and ballast tanks adjacent to cargo tanks;
• 5C-1-7/21, cargo vapor emission control system, where provided.
ii) Bilge and ballast systems: the provisions of 4-6-4/5 and 4-6-4/7 may apply in lieu of the
provisions of Section 5C-1-7; however, pollution prevention measures in Section 5C-1-7
are applicable. Specifically, the following provisions of Section 5C-1-7 are applicable:
• 5C-1-7/5.3.1, except 5C-1-7/5.3.1(b), for ballast pumps;
• 5C-1-7/5.3.2(a) and 5C-1-7/5.3.2(d) for ballast pipe routing;
• 5C-1-7/5.3.3 and 5C-1-7/5.3.4 for discharge of segregated ballast water, dirty ballast
water, etc.,
• 5C-1-7/7.1, 5C-1-7/7.3.3 and 5C-1-7/7.5 for bilge system of pump room, where a
pump room is provided.
iii) Cargo tank protection: a fixed deck foam system complying with 5C-1-7/27 is to be provided.
iv) Electrical systems: provisions of Part 4, Chapter 8 will suffice; provisions of 5C-1-7/31
need not apply.
v) (2007) Electrical systems: Vessels subject to SOLAS are to comply with the requirements
of Clause 4.3.1 of IEC 60092-502 (1999) “Electrical Installations in Ships – Tankers –
Special Features” in accordance with Chapter II-1, Regulation 45.11 of the 2004 Amendments
to SOLAS.
vi) (2007) Electrical systems: Vessels subject to SOLAS are to comply with the requirements
of Clause 4.3.2 of IEC 60092-502 (1999) “Electrical Installations in Ships – Tankers –
Special Features” when cargoes are heated to a temperature within 15°C of their flashpoint
in accordance with Chapter II-1, Regulation 45.11 of the 2004 Amendments to SOLAS.
1.9.2 (2004)
For integrated cargo and ballast system requirements, see 5C-1-7/33.

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 7 Cargo Oil and Associated Systems 5C-1-7

3 Cargo Oil, Stripping and Crude Oil Washing Systems

3.1 General
The following requirements are specific to cargo oil handling, cargo oil stripping and crude oil washing
systems. Requirements not specifically addressed in this section, such as piping material, piping design,
fabrication, testing, general installation details and component certification, as given in Section 4-6-1,
Section 4-6-2 and Section 4-6-3, are to be complied with, as applicable.

3.3 Cargo Oil System

3.3.1 Cargo Pumps
3.3.1(a) Certification. Cargo pumps are to be certified in accordance with 4-6-1/7.3.
3.3.1(b) Alternative means of pumping. In general, should a cargo pump be inoperable, there is
to be an alternative means of pumping from the cargo tanks. This requirement may be met by the
provision of at least two cargo pumps. Where a single deep well or submerged pump is installed
in each cargo tank, an emergency means for pumping out the tank is to be provided. For this
purpose, a portable pump, which can be used safely, may be accepted.
3.3.1(c) Prime movers. Cargo and stripping pump prime movers that contain a source of vapor
ignition are not to be installed in the same space as the pumps and piping. Such prime movers are
to be separated from the pumps by a gastight bulkhead.
3.3.1(d) Cargo and stripping pump drive shaft. Where the pump prime mover is separated from
the pump by a gastight bulkhead, a flexible coupling is to be fitted in the drive shaft passing
through this gastight bulkhead. A stuffing box or a bulkhead gland is to be provided in way of the
shaft penetration at the gastight bulkhead.
Such stuffing box or bulkhead gland is to be gas tight and is to be designed to prevent any leakage
of gas from the pump room into the machinery space.
Means are to be provided for lubricating the stuffing boxes or bulkhead glands from outside the
pump room. The sealing part of these stuffing boxes or bulkhead glands is to be of non-sparking
construction. If a bellows piece is incorporated in the design, it is to be pressure tested before
being fitted.
3.3.1(e) Temperature alarm (1 July 2002). Temperature sensing devices are to be provided for
pump bulkhead shaft glands, pump bearings and pump casings for pumps located in pump room
(see 5C-1-7/3.3.1(c), 5C-1-7/5.3.1(b) and 5C-1-7/7.3.1). High temperature audible and visual
alarms are to be provided at the cargo control room or at the pump control station.
3.3.1(f) Relief valve. A relief valve is to be installed in the discharge of each cargo and stripping
pump. The outlet from the relief valve is to be led to the suction side of the pump. This relief valve
need not be fitted in the case where centrifugal pumps are installed and the piping is designed to
withstand the shut-off head of the pumps.
3.3.1(g) Cargo pump bypass. A by-pass is to be fitted around the cargo pump where cargo
loading is arranged through the riser or suction piping. The bypass may be omitted if the cargo
pump is of a type designed to allow flow through.
3.3.1(h) Pressure gauges. One pressure gauge for each pump is to be located at the pump
discharge. Where pumps are operated by prime movers external to the pump room, additional
pressure gauges are to be installed at either the cargo control room or at the pump prime mover
operating station.
3.3.2 Cargo Oil Piping – Safety Measures
3.3.2(a) Independence of cargo piping. Cargo piping systems are to be independent of all other
piping systems, except for emergency connection to the ballast system, see 5C-1-7/5.3.1(c), and
approved connection to the inert gas main, see 5C-1-7/25.25.4.

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 7 Cargo Oil and Associated Systems 5C-1-7

3.3.2(b) Routing. Cargo piping is not to be led outside of the cargo area, except where permitted
for bow or stern loading and unloading in 5C-1-7/3.3.3. Cargo piping is not to pass through fuel-
oil tanks or spaces containing machinery where sources of ignition are normally present. See also
5C-1-7/3.3.4(a).
3.3.2(c) Provision for expansion. Provisions are to be made for the expansion of cargo piping.
This may be achieved by the use of expansion bellows, slip joints or pipe bends.
3.3.2(d) Static electricity. Cargo piping is be grounded in accordance with the requirements of 4-
6-2/9.15. Cargo loading lines inside the tanks are to be led as low as practicable to reduce the risk
of generating static electricity due to free fall of oil in the tank.
3.3.2(e) Ordinary cast iron. Ordinary cast iron may be used in cargo piping, except that in cargo
piping on weather decks it may be accepted for pressures up to 16 bar (16.3 kgf/cm2, 232 psi)
only. Ordinary cast iron is not to be used for cargo manifolds and associated valves and fittings for
connection to cargo handling hoses. See also 4-6-2/3.1.3 for other limitations for use of ordinary
cast iron.
3.3.3 Bow or Stern Loading and Unloading
Where bow or stern loading and unloading connections are provided, the arrangements are to be as
follows:
i) Cargo lines outside of the cargo area are to be installed outside accommodation spaces,
service spaces, machinery spaces and control stations.
ii) Pipe joints outside of the cargo area are to be welded, except for connections to the
manifold or the loading and unloading equipment.
iii) The cargo loading and unloading lines are to be clearly identified and provided with
means to segregate them from the cargo main line when not in use. The separation is to be
achieved by:
• Two valves, located in the cargo area, which can be locked in the closed position, and
fitted with means to detect leakage past the valves; or
• One valve together with another closing device providing an equivalent standard of
segregation, such as a removable spool piece or spectacle flange.
iv) The loading and unloading connection is to be fitted with a shut-off valve and a blank
flange. The blank flange may be omitted if an equivalent means of closing is incorporated
in the connection to the hose coupling.
v) Arrangements are to be provided for cargo lines outside of the cargo area for easy
draining to a slop tank or cargo tank and for cleaning and inerting. Spill containment is to
be provided under the loading and unloading manifold. The space within 3 m (10 ft) from
the oil spill containment boundary and the manifold is considered to be hazardous.
Accordingly, there is to be no source of ignition present within this space. Electrical
equipment, if installed in this space, is to be of the certified safe type, see 5C-1-7/31.9.
vi) Means of communication (e.g., telephones, two-way portable radios, etc.) are to be provided
onboard between the cargo control station and the location of the cargo shore connection.
See also 5C-1-7/11.11.1 for measures for preventing liquid rising in the vent pipes.
vii) (2003) Fixed deck fire extinguishing system complying with the requirements of
5C-1-7/27.19.
viii) (2010) See 3-4-1/5.3.1 for requirements applicable to the exterior boundaries of
superstructures and deckhouses which face the cargo shore connection, and spill containment.

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 7 Cargo Oil and Associated Systems 5C-1-7

3.3.4 Cargo Piping – Pollution Prevention Measures

3.3.4(a) Routing. For oil carriers and fuel oil carriers of 5,000 tonnes deadweight and above,
cargo piping, including cargo tank vent and sounding pipes, is not to pass through ballast tanks.
Short runs of such pipes may be permitted, provided they have all joints welded and are of wall
thickness not less than that in Column E of 4-6-2/Table 4 or equivalent construction. See also
5C-1-7/5.3.2(a) for ballast pipe routing.
For vessels less than 5,000 tonnes deadweight, cargo piping passing through ballast tanks is to be
steel with a minimum thickness according to Column E of 4-6-2/Table 4, or equivalent construction.
In such cargo piping, all joints are to be welded or have extra heavy flanges; no gland-type
expansion joint is permitted. The number of flanged joints is to be kept to a minimum.
Where at the request of the owner, cargo piping and the valve control piping are located above the
double bottom, the vessel will be assigned with the notation CPP (Cargo Piping Protected). This
applies also to cargo piping and valve control piping installed in pipe tunnel or duct keel.
3.3.4(b) Stripping and small diameter lines. For crude oil carriers of 20,000 tonnes deadweight
and above and product carriers of 30,000 tonnes and above, means are to be provided to drain all
cargo tanks and all oil lines at completion of cargo discharge, where necessary by connection to a
stripping device. The line and pump drainings are to be capable of being discharged either ashore
and to a cargo tank or a slop tank. For discharge ashore, a special small diameter line is to be
provided and is to be connected to the vessel’s deck discharge manifold outboard of the manifold
valves on both sides of the vessel. The cross sectional area of the small diameter line is not to
exceed 10% of that of the main cargo discharge line
3.3.4(c) Sea chests. Where it is necessary to provide a sea connection to the cargo oil pumps to
enable ballasting of cargo tanks during severe weather conditions, tank cleaning, etc., a means of
isolating the pumps from the sea chests when they are not being used for this operation is to be
provided. This is to be achieved by a blank flange or a removable spool piece. The spool piece, if
used, is to be stowed as in 5C-1-7/3.3.4(d) below. A shut-off valve is to be fitted on each side of
the blank flange or the removable spool piece.
Alternatively, two valves are to be installed at the sea chest connection. One of these valves is to
be capable of being locked in the closed position and means – such as a test cock – are to be
provided for detecting leakage past these valves.
3.3.4(d) Connection to ballast system. Connection of the cargo system to the ballast system by a
removable spool piece is only permitted in an emergency. The arrangements of the spool piece are
to include a non-return valve to prevent cargo from entering the ballast system, and shut-off valves
and blind flanges on both the ballast end and the cargo end of the connection. The spool piece is to
be stowed in a conspicuous manner so that it may be readily available whenever the need arises. A
permanent notice is to be displayed to prohibit unauthorized use of the spool piece
3.3.4(e) Crude oil washing system. For crude oil carriers of 20,000 tonnes deadweight and
above, a crude oil washing system is to be installed which complies with:
• MARPOL 73/78, Annex I, Regulation 33,
• IMO Resolutions A.446 (XI) Revised specifications for the design, operation and control of
crude oil washing systems,
• IMO Resolution A.497 (XII) Amendments to the revised specifications for the design, operation
and control of crude oil washing systems, and
• IMO Resolution A.897 (21) Amendments to the revised specifications for the design, operation
and control of crude oil washing systems [Resolution A.446 (XI) as amended by resolution
A.497 (XII)]
Where a crude oil washing system is fitted on a vessel of less than these deadweight sizes, only
requirements concerning safety need be complied with.
The crude oil washing system is to be operated only when the cargo tank is inerted with an inert
gas system complying with 5C-1-7/25.

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 7 Cargo Oil and Associated Systems 5C-1-7

3.3.4(f) Slop tanks. For oil and fuel oil carriers of 150 gross tonnage and above, slop tanks of
number and sizes complying with 5C-1-1/5.1 and MARPOL 73/78, Annex I, Regulation 29 are to
be provided to receive dirty ballast residues, tank washings and other oil residues. Slop tanks are
to be so designed in respect of the position of inlets, outlets, baffles or weirs, where fitted, so as to
avoid excessive turbulence and entrainment of oil or emulsion with water.
3.3.5 Cargo Oil Piping Pressure Tests
After installation, cargo oil piping systems are to be tested to 1.5 times the design pressure of the
system.

3.5 Remotely Operated Valves

3.5.1 Alternative Means of Operation
Remotely operated valves, if located on deck or in the pump room, are to be provided with local,
manual means of operation. This may be a hand wheel or a connection to a portable hand-pump.
Where such valves are located in cargo tanks and such local manual means are not practicable,
alternative means are to be provided for pumping out the cargo tank in the event of a valve
actuator failure. The installation of two independent suctions will be acceptable as an alternative
means.
3.5.2 Valve Actuators
Valve actuators are to be of a type that will prevent the valve from opening in the event of the loss
of pressure in the actuating system. Means are to be provided for indicating open/close position of
the valve.
3.5.3 Valve Actuating System
A pneumatic system is not to be used for actuating valves installed in cargo tanks. Where the
actuating system is hydraulic, arrangements are to be made to lead the hydraulic oil tank vent to
the weather and to fit the vent opening with a flame screen. Hydraulic piping is, in general, to
enter the cargo tank through the highest part of the tank. System operating pressures, on both the
outflow and the return sides, are to be higher than the highest static head of the cargo tank.

5 Ballast System and Oily Water Handling

5.1 Segregated Ballast

For purposes of oil pollution prevention, every crude oil carrier of 20,000 tonnes deadweight and above
and every product carrier of 30,000 tonnes deadweight and above are to be provided with segregated
ballast tanks. The capacity of the segregated ballast tanks is to be such that the vessel may operate safely
on ballast voyages without recourse to the use of cargo tanks for water ballast. However, ballast water may
be carried in cargo tanks in case of severe weather or other emergency conditions, provided that such cargo
tanks have been previously crude oil washed. See 5C-1-1/5 and MARPOL 73/78, Annex I, Regulation 18.

5.3 Ballast System

5.3.1 Ballast Pumps
5.3.1(a) Certification. Ballast pumps are to be certified in accordance with 4-6-1/7.3.
5.3.1(b) Ballast pump prime movers. Ballast pumps are to be located in the cargo pump room or
other similar spaces within the cargo area and are to comply with the same requirements as cargo
pumps in 5C-1-7/3.3.1(c), 5C-1-7/3.3.1(d) and 5C-1-7/3.3.1(e).
5.3.1(c) Deballasting. Where only one ballast pump is provided, a second means of deballasting
is to be provided. This may be by means of an eductor or a temporary connection between the
ballast and cargo piping. The temporary connection may be a portable spool piece arranged in
accordance with 5C-1-7/3.3.4(d).

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 7 Cargo Oil and Associated Systems 5C-1-7

5.3.2 Ballast Piping

5.3.2(a) Routing. For purposes of minimizing oil contamination, for oil carriers or fuel oil carriers
of 5,000 tonnes deadweight and above, ballast piping, including vents and sounding piping for
segregated ballast tanks, is not to pass through cargo tanks. However, short runs of such pipe may
be permitted, provided they are all welded steel pipes with a minimum wall thickness not less than
that in Column E of 4-6-2/Table 4, or equivalent construction. See 5C-1-7/3.3.4(a) for cargo pipe
routing.
For vessels less than 5,000 tonnes deadweight, ballast piping passing through cargo tanks is to be
steel with a minimum thickness according to Column E of 4-6-2/Table 4, or equivalent construction.
In such ballast piping, all joints are to be welded or have extra heavy flanges; no gland-type
expansion joint is permitted. The number of flanged joints is to be kept to a minimum.
5.3.2(b) Hazards (2012). Ballast piping passing through cargo tanks (where permitted) or
connected to ballast tanks adjacent to cargo tanks is not to lead into or pass through spaces where
sources of ignition are normally present except that short lengths of all welded steel pipe may be
specially considered. The pipe is to be adequately secured and is to have minimum wall thickness
according to Column E of 4-6-2/Table 4. See 5C-1-7/1.7.
5.3.2(c) Use of fire main. The fire main may be used for ballasting, or deballasting with
eductors, provided the branch pipe from the fire main used for this purpose is led from the upper
deck and fitted with a stop-check valve.
5.3.2(d) Provision for expansion. Provisions are to be made for the expansion of ballast piping.
This may be achieved by the use of expansion bellows, slip joints or pipe bends.
5.3.3 Discharge of Segregated Ballast
Provisions are to be made so that segregated ballast can be discharged above the waterline in the
deepest ballast condition. Discharge below the waterline is permitted if discharge procedures in
accordance with MARPOL 73/78 Annex I are adhered to.
5.3.4 Discharge of Dirty Ballast and Oil Contaminated Water
5.3.4(a) Processing. Means are to be provided to allow dirty ballast or oil contaminated water
from cargo tank areas to be processed prior to discharging. These means are to include slop tanks
[see 5C-1-7/3.3.4(f)], oil/water interface detectors [see 5C-1-7/5.3.4(c)] and oil discharge monitoring
and control system [see 5C-1-7/5.3.4(b)].
5.3.4(b) Oil discharge monitoring and control system. Oil and fuel oil carriers of 150 gross
tonnage and above are to be provided with an oil discharge monitoring and control system complying
with MARPOL 73/78, Annex I, Regulation 31 and IMO Resolution MEPC.108(49).
5.3.4(c) Oil water interface detector. Oil carriers and fuel oil carriers of 150 gross tonnage and
above are to be provided with an effective oil/water interface detector complying with IMO
Resolution MEPC.5(XIII) for determination of oil/water interface in slop tanks. It is to be
available for use in other tanks where the separation of oil and water is effected, and from which
effluent is intended to discharge directly to the sea.
5.3.4(d) Discharge to sea (2005). Provisions are to be made for the discharge to be led to the
open deck or to either side of the vessel above the waterline in the deepest ballast condition.
Discharge below the waterline is permitted if discharge procedures in accordance with MARPOL
73/78 Annex I are adhered to. The discharge is to be monitored by the oil discharge monitoring
and control system. The discharge lines for dirty ballast and oil-contaminated water may be permitted
to pass through fuel oil tanks, provided that the lines have all joints welded and are of wall thickness
not less than that in Column E of 4-6-2/Table 4 or equivalent construction.
5.3.4(e) Discharge to shore. Means are to be provided to discharge dirty ballast water or oil
contaminated water to shore reception facilities. A discharge manifold for this purpose is to be
located on the open deck on both sides of the vessel. A cargo oil pump, through the emergency
connection in 5C-1-7/3.3.4(d), may be used for this purpose.

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 7 Cargo Oil and Associated Systems 5C-1-7

7 Bilge System

7.1 General
Provision is to be made for removing drainage from pump room bilges and cofferdams in the cargo area.
Bilge systems for machinery spaces and spaces outside the cargo area are not to be used for this purpose.
Overboard discharge of oil or oil-contaminated water from cargo pump room bilges and cofferdams in the
cargo area is to be prohibited unless processed in accordance with 5C-1-7/5.3.4(a).

7.3 Pump Room and Cofferdams Bilge System

The bilge system for the cargo pump room and cofferdams are to be provided with a dedicated bilge pump,
an eductor or a connection to the suction of a cargo or stripping pump.
7.3.1 Dedicated Bilge Pump
Where a bilge pump or eductor is used, it is not to be located, nor is the piping to pass through,
machinery space or other similar spaces where sources of vapor ignition is normally present. Bilge
pumps located in the cargo pump room are to comply with the same requirements as cargo pumps
in 5C-1-7/3.3.1(c), 5C-1-7/3.3.1(d) and 5C-1-7/3.3.1(e).
7.3.2 Cargo or Stripping Pumps as Bilge Pump
Where bilge suction is provided from a cargo or stripping pump, a stop-check valve is to be fitted
in the branch connection to the bilges. Where the bilge suction branch connection is arranged such
that it is subjected to the static head of oil from the filling line during loading, a shut-off valve, in
addition to the stop-check valve, is to be provided in the bilge branch suction connection.
7.3.3 Bilge Pump and Valve Control (2005)
Pump-room bilge suction and discharge valves and the bilge-pump controls are to be operable in
the pump room, unless Flag Administrations have a specific requirement for remote operation,
either from an accessible position outside the pump room or from the pump room casing above the
freeboard deck.

7.5 Bilge Alarms

A high level of liquid in the pump room bilge is to activate an audible and visible alarm in the cargo
control room and on the navigation bridge.

7.7 Discharge of Machinery Space Bilges into Slop Tank

When bilge pumps in the machinery space are arranged to discharge into a cargo slop tank, the discharge
piping is to be arranged as follows:
i) The discharge line is to enter the cargo slop tank from the weather deck through the tank top.
ii) The tank penetration is to be located as close to a vertical tank boundary as practicable.
iii) Within the tank, to prevent the free fall of liquid, the discharge line is to be as short as practicable
and the outlet is to be arranged to discharge against the vertical boundary.
iv) (2012) A stop-check valve is to be provided in the discharge line and is to be located either within
the machinery space or immediately outside of the machinery space, and as close to the machinery
space bulkhead as possible.
v) (2006) In order to prevent cargo vapor from entering the machinery spaces, a loop seal is to be
provided in the discharge line. This loop seal is to be located outside the machinery space, and
preferably, in the cargo pump room. The height of the loop seal is to provide a static head greater
than the pressure setting of the cargo slop tank pressure/vacuum valve, or a minimum of 762 mm
(30 in.), whichever is greater. A means is to be provided to prevent the loop seal from freezing
where exposed to the weather.
vi) A non-return valve is to be located in the discharge line on deck as close to the tank penetration as
practicable.

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 7 Cargo Oil and Associated Systems 5C-1-7

9 Cargo Heating Systems

9.1 Temperature
The temperature of the heating medium is not to exceed 220°C (428°F).

9.3 Steam Heating System

9.3.1 Cargo Oil Backflow
To minimize the risk of cargo oil or vapor returning to the machinery space through the steam
heating system, the following arrangements are to be provided:
• The steam supply and return lines are to be led into the cargo tanks from above the main deck.
• Means are to be fitted to determine whether the condensate return is contaminated with oil.
• All joints in the heating elements within cargo tanks are to be welded. Flanged joints are
permitted for installation purposes, but are to be kept to a minimum.
9.3.2 Inspection Tank
An inspection tank is to be provided for detection of oil contamination in the condensate return.
The tank is to be of the closed type, dedicated to the cargo heating system only, with no
interconnection to any other system, and vented to the weather. The vent outlet is to be fitted with
a corrosion resistant flame screen. The inspection tank may be located within the machinery space,
in which case, the vent is to terminate outside of the cargo area and the area within 3 m (10 ft) of
the outlet is to be considered hazardous.

9.5 Thermal Oil Heating System

9.5.1 General Requirements
Fired and exhaust gas thermal oil heaters are to meet the requirements in 4-4-1/13. The automatic
burner and flow regulation control systems are to be capable of maintaining the thermal oil at the
desired temperature. In no case is the temperature to exceed that indicated in 5C-1-7/9.1.
9.5.2 Indirect Heating Systems (2005)
9.5.2(a) Heating of cargo oil with flash point below 60°C (140°F) is to be by means of a
secondary circuit, which is to be located entirely in the cargo area.
Vents from the thermal oil expansion tank and that from the oil storage tank are to be led to the
weather.
9.5.2(b) The thermal oil expansion tank for the secondary system may be located outside of the
cargo tank area, provided that the requirements in 5C-1-7/9.5.3iii) and iv) are complied with.
9.5.3 Direct Heating System (2005)
Heating systems with a single circuit may be used, provided that the following additional requirements
are complied with:
i) The system is arranged so that a positive pressure is maintained in the heating coils of at
least 3 m (10 ft) water column above the static head of the cargo and vapor. This pressure
differential is to be maintained whether the thermal oil circulating pumps are in operation
or not.
ii) The valves which could isolate individual heating coils in the cargo tanks are provided
with locking arrangements to ensure that the coils are under static pressure at all times.
iii) The thermal oil expansion tank is fitted with high- and low-level alarms.
iv) A means is provided in the thermal oil expansion tank to detect the presence of cargo oil
vapor. Portable equipment may be acceptable, provided that the use of this device will not
cause the escape of cargo oil vapor into the machinery space.

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 7 Cargo Oil and Associated Systems 5C-1-7

11 Cargo Tank Venting

11.1 General Principles

The venting systems of cargo tanks are to be entirely distinct from the vent pipes of the other compartments
of the vessel. The arrangements and position of openings in the cargo tank deck from which emission of
flammable vapors can occur are to be such as to minimize the possibility of flammable vapors being
admitted to enclosed spaces containing a source of ignition, or collecting in the vicinity of deck machinery
and equipment which may constitute an ignition hazard. In accordance with this general principle, the
criteria in 5C-1-7/11.3 to 5C-1-7/11.19 will apply.

11.3 Venting Capacity

The venting arrangements are to be so designed and operated as to ensure that neither pressure nor vacuum
in cargo tanks is to exceed design parameters and be such as to provide for:
i) The flow of the small volumes of vapor, air or inert gas mixtures caused by thermal variations in a
cargo tank in all cases through pressure/vacuum valves;
ii) The passage of large volumes of vapor, air or inert gas mixtures during cargo loading and ballasting,
or during discharging; and
iii) A secondary means of allowing full flow relief of vapor, air or inert gas mixtures to prevent
overpressure or underpressure in the event of the failure of the arrangements in ii). Alternatively,
pressure sensors may be fitted in each tank protected by the arrangements required in ii), with a
monitoring system in the vessel’s cargo control room or the position from which cargo operations
are normally carried out. Such monitoring system is also to provide an alarm facility which is
activated by detection of overpressure or underpressure conditions within a tank.

11.5 Vent Piping

11.5.1 Venting Arrangement
The venting arrangements in each cargo tank may be independent or combined with other cargo
tanks and may be incorporated into the inert gas piping.
11.5.2 Combined Venting System
Where the arrangements are combined with other cargo tanks, either stop valves or other acceptable
means are to be provided to isolate each cargo tank. Where stop valves are fitted, they are to be
provided with locking arrangements, which are to be under the control of the responsible vessel’s
officer. There is to be a clear visual indication of the operational status of the valves or other
acceptable means. Where tanks have been isolated, it is to be ensured that relevant isolation valves
are opened before cargo loading, ballasting or discharging of the tanks is commenced. Any isolation
must continue to permit the flow caused by thermal variations in a cargo tank, in accordance with
5C-1-7/11.3i).
11.5.3 Isolation from Common Venting System
Where it is intended to load, ballast or discharge a cargo tank or a cargo tank group while it is
isolated from the common venting system, such cargo tank or cargo tank group is to be fitted with
means of overpressure and underpressure protection as in 5C-1-7/11.3iii).

11.7 Self-draining of Vent Piping

The venting arrangements are to be connected to the top of each cargo tank and are to be self-draining to
the cargo tanks under all normal conditions of trim and list of the vessel. Where it may not be possible to
provide self-draining lines, permanent arrangements are to be provided to drain the vent lines to a cargo
tank.

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Section 7 Cargo Oil and Associated Systems 5C-1-7

11.9 Flame Arresting Devices

The venting system is to be provided with devices to prevent the passage of flame into the cargo tanks. The
design, testing and locating of these devices are to comply with the following IMO documents:
• MSC/Circ.677 Revised standards for the design, testing and locating of devices to prevent the passage
of flame into cargo tanks in tankers, and
• MSC/Circ.450/Rev.1 Revised factors to be taken into consideration when designing cargo tank venting
and gas freeing arrangements.
Vent outlets from cofferdams and ballast tanks adjacent to cargo tanks are to be fitted with corrosion
resistant flame screens having a clear area through the mesh of not less than the area of the pipe. However,
on vessels intended to carry in fuel oil or petroleum products having a flash point exceeding 60°C (140°F),
the vent outlets from cofferdams and ballast tanks adjacent to these cargo tanks need not be fitted with
flame screens.

11.11 Protection for Tank Overpressurization and Vacuum

11.11.1 Liquid Rising in Vent Pipes
Provision is to be made to guard against liquid rising in the venting system to a height which
would exceed the design head of cargo tanks. This is to be accomplished by:
i) High level alarms or overflow control systems or other equivalent means,
ii) Gauging devices, and
iii) Cargo tank filling procedures.
In the event that protection is by means of an overflow control system, an analysis is to be
submitted to indicate that, in the worst overflowing condition, the tanks will not be overpressurized.
11.11.2 Pressure/Vacuum Valve Setting
Where pressure/vacuum valves are installed, the pressure setting of these valves is to be in
accordance with the following table:

Vessel Size Pressure/Vacuum setting

a) 103 m (337 ft) in length or more P ≤ 0.21 bar (0.21 kgf/cm2, 3 psi)
V ≥ −0.07 bar (–0.07 kgf/cm2, –1 psi)
b) 61 m (200 ft) in length or less P ≤ 0.12 bar (0.12 kgf/cm2, 1.7 psi)
V ≥ −0.07 bar (–0.07 kgf/cm2, –1 psi)
c) Vessels of intermediate lengths Interpolate between (a) and (b)
d) Vessels with specially designed integral tanks P ≤ 0.69 bar (0.70 kg/cm2, 10 psi)
(see 5C-1-1/1.13 and 5C-2-1/1.15).
P = Pressure above atmospheric; V = Pressure below atmospheric

In addition, calculations are to be submitted to show that the cargo tanks will not be subjected to a
pressure or vacuum in excess of their design pressure. See 5C-1-7/11.3 and 5C-1-7/11.17 for P/V
valve capacity requirements and 5C-1-7/21.5.2(d) for pressure/vacuum valve capacity correction.

11.13 Position of Pressure/Vacuum Valves

Openings for pressure release required by 5C-1-7/11.3i) are to:
i) Have as great a height as is practicable above the cargo tank deck to obtain maximum dispersal of
flammable vapors, but in no case less than 2 m above the cargo tank deck;
ii) Be arranged at the furthest distance practicable, but not less than 5 m from the nearest air intakes
and openings to enclosed spaces containing a source of ignition and from deck machinery and
equipment which may constitute an ignition hazard.

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Section 7 Cargo Oil and Associated Systems 5C-1-7

11.15 Pressure/Vacuum Valve By-pass

Pressure/vacuum valves required by 5C-1-7/11.3i) may be provided with a by-pass arrangement when they
are located in a vent main or masthead riser. Where such an arrangement is provided, there are to be
suitable indicators to show whether the by-pass is open or closed.

11.17 Vent Outlets for Large Flow Volumes

Vent outlets for cargo loading, discharging and ballasting required by paragraph 5C-1-7/11.3ii) are to:
i) Permit the free flow of vapor mixtures; or permit the throttling of the discharge of the vapor
mixtures to achieve a velocity of not less than 30 m/s (100 ft/s);
ii) Be so arranged that the vapor mixture is discharged vertically upwards;
iii) Where the method is by free flow of vapor mixtures, be such that the outlet is to be not less than 6
m above the cargo tank deck or fore and aft gangway if situated within 4 m (13.2 ft) of the
gangway and located not less than 10 m (33 ft) measured horizontally from the nearest air intakes
and openings to enclosed spaces containing a source of ignition and from deck machinery and
equipment which may constitute an ignition hazard;
iv) Where the method is by high velocity discharge, be located at a height not less than 2 m (6.6 ft)
above the cargo tank deck and not less than 10 m (33 ft) measured horizontally from the nearest
air intakes and openings to enclosed spaces containing a source of ignition and from deck machinery
and equipment which may constitute an ignition hazard. These outlets are to be provided with high
velocity devices of an approved type;
v) Be designed on the basis of the maximum designed loading rate multiplied by a factor of at least
1.25 to take account of gas evolution, in order to prevent the pressure in any cargo tank from
exceeding the design pressure. The master is to be provided with information regarding the maximum
permissible loading rate for each cargo tank and in the case of combined venting systems, for each
group of cargo tanks.

11.19 Arrangement for Combination Carriers

In combination carriers, the arrangement to isolate slop tanks containing oil or oil residues from other cargo
tanks are to consist of blank flanges which will remain in position at all times when cargoes other than liquid
cargoes having flash point of 60°C (140°F) or less are carried.

13 Cargo Tank Level Gauging

Means are to be provided to measure the level of liquid in cargo tanks. Such means are to be as specified
below.

13.1 Cargo Tanks Fitted with Inert Gas System

Cargo tanks fitted with an inert gas system are to be provided with approved closed level gauging devices
which will not permit the escape of cargo vapor to the atmosphere when being used. Such devices may be
of the fixed or portable type.

13.3 Cargo Tanks not Fitted with Inert Gas System

Cargo tanks not fitted with an inert gas system may be provided with sounding pipes, ullage measurement
fittings, etc., which allow a limited amount of cargo vapor to escape into the atmosphere when being used.
Such devices are to be installed in the weather.

15 Cargo Tank Purging and/or Gas-freeing

15.1 General (2011)

Arrangements for purging and/or gas freeing are to be such as to minimize the hazards due to the dispersal
of flammable vapors in the atmosphere and to flammable mixtures in a cargo tank. Reference may be made
to IMO documents MSC/Circ.677 and MSC/Circ.450/Rev.1 (see 5C-1-7/11.9).

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Section 7 Cargo Oil and Associated Systems 5C-1-7

Where a fixed gas-freeing system, independent of inert gas system, is located in a non-hazardous area and
is connected to the cargo piping or cargo tanks, care is to be taken to prevent cargo and/or cargo vapor
from entering the gas-freeing installation, when not in use.
The connection is to include the following arrangement:
i) A non-return valve located within the cargo area,
ii) A shut-off valve located at the non-hazardous space boundary and shut-off valve at the cargo side
of the non-return valve,
iii) A spectacle flange on the cargo side of the non-return valve,
iv) The shut-off valve located at the non-hazardous space boundary is to be interlocked such that the
valve is to open as the fans are started, and is to close when the fans are stopped.

15.3 Vessels Fitted with Inert Gas System

When the vessel is provided with an inert gas system, the cargo tanks are to first be purged in accordance
with the provisions of 5C-1-7/25.25 until the concentration of hydrocarbon vapors in the cargo tanks has
been reduced to less than 2% by volume. Thereafter, venting may be at the cargo tank deck level.

15.5 Vessels without Inert Gas System

When the vessel is not provided with an inert gas system, the operation is to be such that the flammable
vapor is initially discharged:
i) Through the vent outlets, as specified in 5C-1-7/11.17; or
ii) Through outlets at least 2 m (6.6 ft) above the cargo tank deck level with a vertical efflux velocity
of at least 30 m/s (100 ft/s) maintained during the gas-freeing operation; or
iii) Through outlets at least 2 m (6.6 ft) above the cargo tank deck level with a vertical efflux velocity
of at least 20 m/s (66 ft/s) and which are protected by suitable devices to prevent the passage of flame.
When the flammable vapor concentration at the outlet has been reduced to 30% of the lower flammable
limits, gas-freeing may thereafter be continued at the cargo tank deck level.

17 Ventilation and Gas Detection

17.1 Cargo Pump Room Ventilation

17.1.1 General (2006)
Cargo pump rooms are to be mechanically ventilated and discharges from the exhaust fans are to
be led to a place on the open deck where such discharges will not cause a fire or explosion hazard.
The ventilation of these rooms is to have sufficient capacity to minimize the possibility of
accumulation of flammable vapors. The number of changes of air is to be at least 20 per hour,
based upon the gross volume of the space. The air ducts are to be arranged so that all of the space
is effectively ventilated. In particular, the intakes are to be arranged as per 5C-1-7/17.1.2. The
ventilation is to be of the suction type using fans of the non-sparking construction. See 5C-1-7/17.1.3.
The inlets and outlets of cargo pump room ventilation systems are to be capable of being closed
from outside the cargo pump room. The means of closing are to be easily accessible, as well as
prominently and permanently marked, and are to indicate whether the shut-off is open or closed.
17.1.2 Arrangements of Air Intakes
The ventilation trunking within the cargo pump room is to be arranged as follows:
17.1.2(a) Main intakes (2005). The main intakes are to be located just above the platform plates
on bottom longitudinals or inner bottom so that the air in the bilge spaces can be extracted. The
platform plates are to be of the open grating type to allow the free flow of air.

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Section 7 Cargo Oil and Associated Systems 5C-1-7

17.1.2(b) Emergency intakes. Emergency intakes (or intake) are to be provided at approximately
2 m (6.5 ft) above the lowest platform plating so that they can be used when the main intakes, as
stated in 5C-1-7/17.1.2(a), are sealed off due to flooding in the bilges. The air change, when only
the emergency intakes are in use, is to be at least 15 air changes per hour.
17.1.2(c) Dampers. Where the emergency intakes share the main exhaust ducts with the main
intakes, the emergency intakes are to be provided with dampers capable of being opened or closed
from the exposed main deck and within the pump room. The dampers may be omitted if the fan
capacity and intakes dimensions are sized such that, with both main and emergency intakes operating
simultaneously, the main intakes are still capable of providing at least 20 air changes per hour.
17.1.3 Fans and Fan Motors
Fan motors are to be located outside the pump room and outside the ventilation ducts. Fans are to
be of non-sparking construction in accordance with 4-8-3/11. Provision is to be made for remote
or automatic shutdown of the fan motors upon release of the fire-extinguishing medium.
17.1.4 Gas Detection System (2012)
The cargo pump room is to be fitted with a fixed gas detection system complying with the following:
i) The system is to be arranged to continuously measure the concentration of hydrocarbon
gas. A system using sequential sampling may be installed, provided the system is dedicated
to pump room sampling only, so as to optimize sampling cycle.
ii) Sampling points or detector heads are to be located in suitable positions in order that
potentially dangerous leakages are readily detected. Suitable positions may be the exhaust
ventilation duct and lower part of the pump room above the floor plate level.
iii) The system is to give a visual indication in the cargo control room of the level of
concentration of hydrocarbon and gases, and is to initiate a continuous visual and audible
alarm if the concentration exceeds 10% of the lower flammable limit. Such alarm is to be
provided in the cargo control room, pump room, engine control room and on the navigation
bridge.
iv) Components of the system installed in the cargo pump room are to be of the intrinsically
safe type (Ex ia or ib). See 5C-1-7/31.9.
See 5C-1-7/20 for fixed hydrocarbon gas detection system requirements.

17.3 Precautions for Ventilation of Accommodation and Machinery Spaces

The arrangement of ventilation inlets and outlets and other deckhouse and superstructure boundary space
openings are to be such as to complement the provisions of 5C-1-7/11. Such vents, especially for
machinery spaces, are to be situated as far aft as practicable. Due consideration in this regard is to be given
when the vessel is equipped to load or discharge at the stern. Sources of ignition such as electrical equipment
are to be so arranged as to avoid an explosion hazard.

17.5 Pipe Tunnel or Duct Keel Ventilation

17.5.1 General
A permanent mechanical ventilating system is to be provided for a pipe tunnel or duct keel. Where
a permanent lighting system is installed in such a space, the ventilation system is to be capable of
providing at least eight (8) changes of air per hour, based on the gross volume of the space. The
system is to have mechanical exhaust, natural or mechanical supply, and ducting, as required to
effectively purge this space and all connecting access trunks. Fan motors are to be located outside
the space in question and outside the ventilation ducts. Fans are to be of non-sparking construction
in accordance with 4-8-3/11.
17.5.2 Gas Detection System
An approved gas detection system complying with 5C-1-7/17.1.4 is to be provided to monitor the
pipe tunnel.

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Section 7 Cargo Oil and Associated Systems 5C-1-7

17.7 Portable Gas Detectors (2001)

Every oil carrier is to be provided with at least two portable gas detectors capable of measuring flammable
vapor concentrations in air and at least two portable oxygen (O2) analyzers, unless each gas detector can
also function as an oxygen analyzer. See also 5C-1-7/19.5.1 and 5C-1-7/25.33. Suitable means are to be
provided for the calibration of the instruments.

17.9 Gas Sampling System Installation

Gas sampling systems with gas-analyzing/measurement units not certified safe for installation in a hazardous
area may have such units installed in a safe area, such as the cargo control room, or the navigation bridge,
provided that the following installation details are complied with.
i) The gas-analyzing unit is to be mounted on the forward bulkhead of the safe space, except as
specially permitted in vi).
ii) The sampling lines are not to run through safe spaces, except where specially permitted in vi).
iii) Bulkhead penetrations of sampling pipes between safe and hazardous areas are to be of approved
types and have the same fire integrity as the division penetrated. An isolation valve is to be fitted
in each of the sampling lines at the bulkhead on the safe side.
iv) The gas sampling pipes are to be equipped with flame arresters. Sample gas is to be exhausted to
the atmosphere with outlets away from sources of ignition.
v) (2001) The gas detection equipment, including sampling piping, sampling pumps, solenoids,
analyzing units, etc., are to be located in a reasonably gas-tight steel cabinet (e.g., fully enclosed
steel cabinet with gasketed door) which is to be monitored by its own sampling point. At a gas
concentration above 30% of the lower flammable limit inside the steel cabinet, the entire
analyzing unit is to be automatically shutdown. Shutdown of the unit is to be alarmed at both the
cargo control room and the navigation bridge.
vi) Where the cabinet cannot be mounted directly on the forward bulkhead, sampling pipes are to be
of steel or other equivalent material and without detachable connections, except for the connection
points for isolating valves at the bulkhead and for the analyzing units. Runs of the sampling pipes
within the safe space are to be as short as possible.

17.11 Ventilation for Combination Carriers

In combination carriers, all cargo spaces and any enclosed spaces adjacent to cargo spaces are to be capable of
being mechanically ventilated. The mechanical ventilation may be provided by portable fans. An approved
fixed gas warning system capable of monitoring flammable vapors is to be provided in cargo pump rooms
and pipe ducts and cofferdams adjacent to slop tanks (see 5C-1-7/17.1.4 and 5C-1-7/17.5.2). Suitable
arrangements are to be made to facilitate measurement of flammable vapors in all other spaces within the
cargo tank area. Such measurements are to be made possible from open deck or easily accessible positions.

19 Double Hull Space Inerting, Ventilation and Gas Measurement

19.1 Air Supply

Double hull and double bottom spaces in way of cargo tanks are to be fitted with suitable connections for
the supply of air.

19.3 Vessels Fitted with Inert Gas System

On oil carriers required to be fitted with inert gas systems:
i) Double hull spaces are to be fitted with suitable connections for the supply of inert gas;
ii) Where such spaces are connected to a permanently fitted inert gas distribution system, means are
to be provided to prevent hydrocarbon gases from the cargo tanks entering the double hull spaces
through the system;
iii) Where such spaces are not permanently connected to an inert gas distribution system, appropriate
means are to be provided to allow connection to the inert gas main.

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 7 Cargo Oil and Associated Systems 5C-1-7

19.5 Provisions for Gas Measurement

19.5.1 Portable Gas Measuring Detectors (2001)
Suitable portable detectors for measuring oxygen and flammable vapor concentrations are to be
provided. See 5C-1-7/17.7 regarding the required number of detectors. In selecting these detectors,
due attention is to be given for their use in combination with the fixed gas-sampling-line systems
referred to in 5C-1-7/19.5.2.
19.5.2 Fixed Gas Sampling System
Where the atmosphere in double hull spaces cannot be reliably measured using flexible gas sampling
hoses, such spaces are to be fitted with permanent gas sampling lines. The configurations of such
line systems are to be adapted to the design of such spaces.
19.5.3 Piping of Gas Sampling Lines
The materials of construction and the dimensions of gas sampling lines are to be such as to
prevent restriction. Where plastic materials are used, they are to be electrically conductive.
19.5.4 Gas Sampling System Installation
For gas sampling systems with gas-analyzing/measurement units not certified safe for installation
in a hazardous area, see 5C-1-7/17.9.
19.5.5 Gas Sampling System for Oil Carriers 20,00 DWT and Above (2012)
In addition to the requirements in 5C-1-7/19.5.1 through 5C-1-7/19.5.3, oil carriers of 20,000
tonnes deadweight and above, shall be provided with a fixed hydrocarbon gas detection system
complying with 5C-1-7/20 for measuring hydrocarbon gas concentrations in all ballast tanks and
void spaces of double-hull and double-bottom spaces adjacent to the cargo tanks, including the
forepeak tank and any other tanks and spaces under the bulkhead deck adjacent to cargo tanks.
19.5.6 Oil Tankers Provided with Constantly Operating Inerting Systems (2012)
Spaces within oil tankers provided with constantly operating inerting systems need not be
equipped with fixed hydrocarbon gas detection equipment in those spaces.
19.5.7 Cargo Pump Rooms (2012)
Notwithstanding the above, cargo pump rooms subject to the provisions of 5C-1-7/3.3.1, 5C-1-7/7.5,
5C-1-7/17.1.4 and 5C-1-7/31.15 need not comply with the requirements of 5C-1-7/19.5.2.

20 Fixed Hydrocarbon Gas Detection System (2012)

20.1 Application
Details of fixed hydrocarbon gas detection systems as required by Section 5C-1-7 are to be provided.
A combined gas detection system required by 5C-1-7/19.5.2 and 5C-1-7/17.1.4 may be accepted in cases
where the system fully complies with the requirement of regulation II-2/2 of SOLAS 1974, as amended.

20.3 Engineering Specification

20.3 1 General
20.3.1(a) Performance Standards. The fixed hydrocarbon gas detection system referred to in
Section 5C-1-7 shall be designed, constructed and tested to the satisfaction of ABS based on
performance standards per the Guidelines for the design, construction and testing of fixed hydrocarbon
gas detection system, MSC.1/Circ.1370.
20.3.1(b) Arrangement. The system shall be comprised of a central unit for gas measurement and
analysis and gas sampling pipes in all ballast tanks and void spaces of double-hull and double-
bottom spaces adjacent to the cargo tanks, including the forepeak tank and any other tanks and
spaces under the bulkhead deck adjacent to cargo tanks.

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20.3.1(c) Systems Integration. The system may be integrated with the cargo pump-room gas
detection system, provided that the spaces referred to in 5C-1-7/20.3.1(b) are sampled at the rate
required in 5C-1-7/20.5.3(a). Continuous sampling from other locations may also be considered
provided the sampling rate is complied with.

20.5 Component Requirements

20.5.1 Gas Sampling Lines
20.5.1(a) Common Sampling Lines. Common sampling lines to the detection equipment shall not
be fitted, except the lines serving each pair of sampling points as required in 5C-1-7/20.5.1(c).
20.5.1(b) Materials. The materials of construction and the dimensions of gas sampling lines shall
be such as to prevent restriction. Where non-metallic materials are used, they shall be electrically
conductive. The gas sampling lines shall not be made of aluminum.
20.5.1(c) Lines Sizes and Arrangement. The configuration of gas sampling lines shall be adapted
to the design and size of each space. Except as provided in 5C-1-7/20.5.1(d) and 5C-1-7/20.5.1(e),
the sampling system shall allow for a minimum of two hydrocarbon gas sampling points, one
located on the lower and one on the upper part where sampling is required. When required, the
upper gas sampling point shall not be located lower than 1 m (3.3 ft) from the tank top. The
position of the lower located gas sampling point shall be above the height of the girder of bottom
shell plating but at least 0.5 m (1.65 ft) from the bottom of the tank and it shall be provided with
means to be closed when clogged. In positioning the fixed sampling points, due regard should also
be given to the density of vapors of the oil products intended to be transported and the dilution
from space purging or ventilation.
20.5.1(d) Sampling in Tank. For ships with deadweight of less than 50,000 tonnes, ABS may allow
the installation of one sampling location for each tank for practical and/or operational reasons.
20.5.1(e)Ballast and Double-bottom Tanks. For ballast tanks in the double-bottom, ballast tanks
not intended to be partially filled and void spaces, the upper gas sampling point is not required.
20.5.1(f) Lines Cleaning. Means shall be provided to prevent gas sampling lines from clogging
when tanks are ballasted by using compressed air flushing to clean the line after switching from
ballast to cargo loaded mode. The system shall have an alarm to indicate if the gas sampling lines
are clogged.
20.5.2 Gas Analysis Unit
The gas analysis unit shall be located in a safe space and may be located in areas outside the ship's
cargo area; for example, in the cargo control room and/or navigation bridge in addition to the hydraulic
room when mounted on the forward bulkhead, provided the following requirements are observed:
i) Sampling lines shall not run through gas safe spaces, except where permitted under
5C-1-7/20.5.2v);
ii) The hydrocarbon gas sampling pipes shall be equipped with flame arresters. Sample
hydrocarbon gas is to be led to the atmosphere with outlets arranged in a safe location, not
close to a source of ignitions and not close to the accommodation area air intakes;
iii) A manual isolating valve, which shall be easily accessible for operation and maintenance,
shall be fitted in each of the sampling lines at the bulkhead on the gas safe side;
iv) The hydrocarbon gas detection equipment including sample piping, sample pumps, solenoids,
analyzing units etc., shall be located in a reasonably gas-tight cabinet (e.g., fully enclosed
steel cabinet with a door with gaskets) which is to be monitored by its own sampling
point. At a gas concentration above 30% of the lower flammable limit inside the steel
enclosure the entire gas analyzing unit is to be automatically shut down; and
v) Where the enclosure cannot be arranged directly on the bulkhead, sample pipes shall be of
steel or other equivalent material and without detachable connections, except for the
connection points for isolating valves at the bulkhead and analyzing unit, and are to be
routed on their shortest ways.

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Section 7 Cargo Oil and Associated Systems 5C-1-7

20.5.3 Gas Detection Equipment

20.5.3(a) Lines Spacing. The gas detection equipment shall be designed to sample and analyze
from each sampling line of each protected space, sequentially at intervals not exceeding 30 min.
20.5.3(b) Portable Equipment. Means shall be provided to enable measurements with portable
instruments, in case the fixed system is out of order or for system calibration. In case the system is
out of order, procedures shall be in place to continue to monitor the atmosphere with portable
instruments and to record the measurement results.
20.5.3(c) Audible and Visual Alarms. Audible and visual alarms are to be initiated in the cargo
control room, navigation bridge and at the analyzing unit when the vapor concentration in a given
space reaches a pre-set value, which shall not be higher than the equivalent of 30% of the lower
flammable limit.
20.5.3(d) Testing and Calibrating. The gas detection equipment shall be so designed that it may
readily be tested and calibrated.

21 Cargo Vapor Emission Control Systems

21.1 Application
While the installation of a cargo vapor control system is optional for classification purposes, where installed,
the provisions of 5C-1-7/21 are applicable. These provisions cover systems employed to collect cargo oil
vapor, primarily during cargo loading operations, for disposal at shore facilities. Systems satisfying these
provisions will be assigned with the notation VEC. Systems satisfying the additional provisions of 5C-1-7/21.19
for lightering operation will be assigned with the notation VEC-L.

21.3 Plans and Data to be Submitted

Where a cargo vapor emission control system is to be installed, the following plans and particulars are to
be submitted.
• Cargo vapor emission control and collection piping; associated venting and inert gas systems; drainage
arrangements; bill of materials.
• Maximum allowable cargo transfer rate; pressure/vacuum valve capacity test reports and settings;
associated calculations (see 5C-1-7/21.5).
• Tank gauging systems; overfill control, instrumentation and alarm systems; overfill settings.
• Hazardous locations and certified safe electrical equipment in these locations.

21.5 Cargo Transfer Rate

21.5.1 Maximum Allowable Cargo Transfer Rate
The cargo vapor emission control system is to be designed for a predetermined maximum allowable
cargo transfer rate, which is not to exceed the least of the following:
i) The maximum design loading rate used to determine the pressure setting of the
pressure/vacuum valves.
ii) The maximum design discharge rate used to determine the vacuum setting of the
pressure/vacuum valves.
iii) A rate determined by pressure drop calculations where, for a given pressure at the vapor
reception facility connection to the vessel, the pressure in any tank connected to the
system exceeds 80 percent of the pressure setting of any pressure/vacuum valve in the
cargo tank venting system.

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21.5.2 Calculations
The following calculations are to be submitted to substantiate the adequacy of the proposed cargo
transfer rates. In these calculations, for tanks connected to the pressure/vacuum breaker, the
capacity of the pressure/vacuum breaker may be taken into account.
21.5.2(a) Pressure/vacuum valve pressure relief capacity. Calculations are to verify that the
valve can discharge vapor at a flow rate equal to 1.25 times maximum design loading rate specified
in 5C-1-7/21.5.1i) while maintaining a pressure in the tank not exceeding the design head of the
tank. Where spill valve or rupture disks are fitted (see 5C-1-7/21.15.5), the pressure maintained in
the tank is not to exceed the designed opening pressures of these devices.
21.5.2(b) Pressure/vacuum valve vacuum relief capacity. Calculations are to verify that, at the
maximum designed discharge rate specified in 5C-1-7/21.5.1ii), the vacuum relief setting will not
allow the tank to exceed its allowable designed vacuum.
21.5.2(c) System pressure drop. Calculations are to demonstrate that the requirement of
5C-1-7/21.5.1iii) is satisfied for each cargo handled. The pressure drop through the system, from
the most remote cargo tank to the vessel shipside vapor connection, is to be determined. Hoses
normally carried onboard the vessel are to be included in the calculation. The calculations are to
be performed at several transfer rates, including the maximum transfer rate, assuming a 50 percent
cargo vapor and air mixture and a vapor growth rate appropriate for the specific cargo being
considered in the calculation.
21.5.2(d) Pressure/vacuum valve capacity correction. Where the capacities of a pressure/vacuum
valve are obtained by testing with air only, the following equations may be used to correct the
capacities for cargo oil vapor.
QA = QL ⋅ R ⋅ F

Pv
R = 1 + 0.25 SI & MKS units
0.88
Pv
R = 1 + 0.25 US units
12.5

ρ va
F=
ρa
where
QA = required air equivalent volumetric flow rate; m3/h (gpm) (or consistent
system of units)
QL = cargo transfer rate; m3/h (gpm) (or consistent system of units)
R = vapor growth rate; to be as calculated above or 1.25, whichever is larger;
dimensionless
F = density correction factor; dimensionless
Pv = saturated vapor pressure, absolute, at 46.1°C (115°F); barA (kgf/cm2A, psiA)
ρva = vapor-air mixture density at 46.1°C (115°F) and pressure setting of
pressure/vacuum valve; kg/m3 (lb/ft3) (or consistent system of units)
ρa = air density at 46.1°C (115°F) and pressure setting of pressure/vacuum valve;
kg/m3 (lb/ft3) (or consistent system of units)

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Section 7 Cargo Oil and Associated Systems 5C-1-7

21.7 Vapor Collection Piping

Vapor collection piping is not to interfere with the proper operation of the cargo tank venting system. Suitable
means, located on deck, are to be provided to isolate the vapor collection system from the inert gas system. This
requirement may be considered met if the vapor collection system is connected to the inert gas main forward of
the non-return devices and the positive means of closure required by 5C-1-7/25.19.8. Means are to be provided
to drain and collect condensate from each low point in the vapor collection piping system.
Vessels collecting vapors from incompatible cargoes simultaneously are to have a means of maintaining
separation of the vapors throughout the collection system.

21.9 Ship Side Vapor Connection

21.9.1 Location and Valve
The ship side vapor connection to shore facilities is to be installed as close to each cargo transfer
manifold as practicable in an easily accessible position and is to be fitted with a shutoff valve
capable of manual operation.
21.9.2 Connection Flange
The ship side vapor connection flange, vapor hose flange or vapor line adapter flange, as applicable,
for connection to shore facilities is to have dimensions meeting ANSI B16.5 Pipe Flanges and
Flanged Fitting for Class 150 flanges. The flange face of the ship side vapor connection flange is
to be fitted with a protruding stud, 12.7 mm (1/2 in.) in diameter and at least 25.4 mm (1 in.) long.
This is to facilitate its centering with the vapor hose flange, whose flange face is to be drilled with
a corresponding hole of 16 mm (5/8 in.) in diameter.
21.9.3 Color Code and Labeling
The last 1.0 m (3.3 ft) of vapor piping inboard of the vapor connection flange is to be painted
red/yellow/red with the red bands 0.1 meter (0.33 feet) wide, and the yellow band 0.8 meter (2.64 feet)
wide. The yellow band is to be labeled with “VAPOR” in black letters at least 50 mm (2 in.) high.
21.9.4 Hoses
Hoses, carried onboard for shore/lightering vapor connection, are to comply with the following:
• Maximum allowable working pressure is to be at least 0.34 bar (0.35 kgf/cm2, 5 psi).
• Maximum allowable vacuum is to be at least 0.14 bar (0.14 kgf/cm2, 2 psi) below atmospheric.
• Burst pressure is not to be less than five times its maximum allowable working pressure.
• Electrically continuous.
• Abrasion resistant and non-kinking.
• Provided with hose handling equipment, e.g., hose saddles.

21.11 Pressure/Vacuum Protection of Cargo Tanks

21.11.1 Pressure/Vacuum Valves
For vessels intended to operate with vapor emission control systems, the cargo tanks are to be equipped
with a venting system complying with 5C-1-7/11. Each tank venting system is to be fitted with a
pressure/vacuum relief valve of suitable setting and capacity (see 5C-1-7/21.11.2). A pressure/vacuum
breaker installed in an inert gas main may also be considered for satisfying this purpose.
21.11.2 Pressure/Vacuum Valve Relief Capacity and Setting
21.11.2(a) Relief capacity. The pressure relief capacity of the pressure/vacuum valve (or
breaker) installed in the venting system is to be based on 1.25 times the designed loading rate. The
vacuum relief capacity is to be based on the maximum discharge rate. See 5C-1-7/11.17 and
5C-1-7/21.5. Relief capacities are to be verified by tests (e.g., in accordance with API Standard 2000)
or by calculations, as in the case of pressure/vacuum breaker. Flame arrestors, where fitted, are to
be included in the tests or calculations. Test or calculation reports are to be submitted for review.

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21.11.2(b) Settings. The maximum pressure and vacuum settings are to be in accordance with
5C-1-7/11.11. Further, the pressure relief setting is not to cause the valve to open at a pressure of
less than 0.07 bar (0.07 kg/cm2, 1 psig). The vacuum relief setting is not to open at less than 0.03
bar (0.03 kg/cm2, 0.5 psi) below atmospheric pressure in the tank vapor space.
21.11.3 Valve Operational Checks
The pressure/vacuum valve (or breaker) is to have a mechanical means to check its proper
operation and to ensure that it will not remain in the open position. A pressure/vacuum breaker of
the liquid filled type is to be fitted with a level gauge, complete with mechanical protection, for
determining its set pressure.
21.11.4 Pressure/Vacuum Displays and Alarms
Displays of pressure/vacuum in the vapor collection piping are to be fitted at each cargo transfer
control station. In addition, high and low pressure (or vacuum) alarms, set as follows, are also to
be fitted:
• For high-pressure alarm, no higher than 90% of the lowest pressure setting of pressure/vacuum
valves in the venting system.
• For low-pressure alarm, no lower than 0.01 bar (0.01 kgf/cm2, 0.144 psi) for inerted cargo
tanks; and no lower than the lowest vacuum setting of the pressure/vacuum valve in the venting
system for non-inerted tanks.
Sensors for the displays and alarms are to be installed in the main vapor collection line and are to
be capable of being isolated for maintenance.

21.13 Gauging Systems

A closed tank gauging system capable of measuring the full height of the tank is to be fitted. If portable
gauging devices are used, the number of devices available is to be equal to the maximum number of tanks
that can be loaded simultaneously, plus two additional units. A tank level display is to be provided at each
cargo transfer control station.

21.15 Tank Overfill Protection

21.15.1 High Level and Overfill Alarms
Each cargo tank is to be fitted with a high level alarm and an overfill alarm, which are to be
independent of each other. The overfill alarm is at least to be independent of the tank gauging
system. The alarm systems are to be self-monitoring (or fitted with other means of testing) and
provided with alarms for failure of tank level sensor circuits and power supply. All alarms are to
have visual and audible signals and are to be given at each cargo transfer control station. In
addition, overfill alarms are also to be given in the cargo deck area in such a way that they can be
seen and heard from most locations.
21.15.2 Level Alarm Setting
The high level alarm is to be set at no less than that corresponding to 95% of tank capacity, and
before the overfill alarm level is reached. The overfill alarm is to be set so that it will activate
early enough to allow the crew in charge of the transfer operations to stop the transfer before the
tank overflows.
21.15.3 Alarm Labels
At each cargo transfer control station, the high level alarms and the overfill alarms are to be
identified with the labels “HIGH LEVEL ALARM” and “TANK OVERFILL ALARM”, respectively,
in black letters at least 50 mm (2 inches) high on a white background.
21.15.4 Operational Checks
Each alarm system is to have a means of checking locally at the tank to assure proper operation
prior to the cargo transfer operation. This is not required if the system has a self-monitoring feature.

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Section 7 Cargo Oil and Associated Systems 5C-1-7

21.15.5 Mechanical Overfill Control Devices

Installation of spill valves, rupture disks and other such devices will not alleviate the alarm
requirements in 5C-1-7/21.15.1 and 5C-1-7/21.15.2. Where fitted, they are to meet the following
provisions.
21.15.5(a) Spill Valves. Spill valves are to be designed to relieve cargo at a pressure higher than
the pressure setting of the pressure/vacuum valves at maximum cargo transfer rate and vapor rate
of 1.25 times maximum cargo transfer rate. At relieving, the tank is to be subjected to a pressure
no higher than the design head of the tank. Construction of spill valves is to meet a recognized
standard such as ASTM F1271 Standard Specification for Spill Valves for Use in Marine Tank
Liquid Overpressure Protection Applications. Spill valves are to be so installed as to preclude
unwarranted opening due to sloshing.
21.15.5(b) Rupture Disks. The installation of rupture disks is to meet the intent of 5C-1-7/21.15.5(a),
with the exception of compliance with ASTM F1271.

21.17 Electrical Installations

Electrical installations are to meet 5C-1-7/31.

21.19 Vapor Collection for Lightering Operations

21.19.1 General
Lightering is the transfer of cargo oil from one vessel to another. Provisions in 5C-1-7/21.19 are
intended for service vessels, which receive and transport cargo oil between a facility and another
vessel. The vapor collection system of such a vessel is to meet the requirements of 5C-1-7/21.1
through 5C-1-7/21.17 and the additional provisions of 5C-1-7/21.19.
21.19.2 Oxygen Analyzer
Service vessels are to be fitted with an oxygen analyzer within 3 m (10 ft) of its vapor connection
flange. The analyzer is to provide a display of the oxygen content in the vapor collection piping as
well as giving an alarm when the oxygen content exceeds 8 percent by volume, at the cargo transfer
control station. Means for testing and calibrating the oxygen analyzer are to be provided onboard.
21.19.3 Hose Inerting
Means for inerting the transfer hose between vessels is to be provided on the service vessel.
21.19.4 Insulating Flange
A means of electrical insulation (i.e., an insulating flange or a length of non-conducting hose) is to
be provided at the vessel vapor connection flange.
21.19.5 Detonation Arrestor
Where the cargo tanks of the lightered vessel are not inerted, a detonation arrestor is to be installed
in the vapor collection piping not more than 3 meters (10 feet) inboard of the vapor connection
flange on the service vessel. The detonation arrestor is to be capable of arresting a detonation from
either side of the device, and be built to a recognized standard.
21.19.6 Vapor Balancing
Vapor balancing is not to be utilized when only the vessel to be lightered has inerted tanks.

21.21 Instruction Manual

An instruction manual including procedures relating to vapor emission control operations is to be submitted
solely for verification that the information in the manual on the cargo vapor emission control system is
consistent with the design information considered in the review of the system. The instruction manual is
also to include:
• Cargo tanks to which the cargo vapor emission control system applies; and
• Maximum cargo transfer rate and maximum specific weight of cargo vapor considered.

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23 Cargo Tank Protection

23.1 Inert Gas System and Deck Foam System (2011)

For oil carriers of 20,000 tonnes deadweight and upwards, the protection of the cargo tanks deck area and
cargo tanks are to be achieved by a fixed deck foam system and a fixed inert gas system, in accordance
with the requirements of 5C-1-7/25 and 5C-1-7/27, respectively, except that, in lieu of these installations,
alternative arrangements and equipment, as indicated below, may be accepted.
Oil carriers of less than 20,000 tonnes deadweight are to be provided with a deck foam system or equivalent.
Where, in addition to the deck foam system or equivalent, a fixed inert gas system is installed on oil carriers
of less than 20,000 tonnes deadweight, the system is to be in accordance with the requirements of 5C-1-7/25.
23.1.1 Alternative to Deck Foam System
To be considered equivalent, the system proposed in lieu of the deck foam system is to be:
i) Capable of extinguishing spill fires and also preclude ignition of spilled oil not yet ignited;
and
ii) Capable of combating fires in ruptured tanks.
23.1.2 Alternative to Inert Gas System
To be considered equivalent, the system proposed in lieu of the fixed inert gas system is to be:
i) Capable of preventing dangerous accumulations of explosive mixtures in intact cargo tanks
during normal service throughout the ballast voyage and necessary in-tank operations; and
ii) So designed as to minimize the risk of ignition from the generation of static electricity by
the system itself.

23.3 Crude Oil Washing

All crude oil carriers, regardless of size, operating with a cargo tank cleaning procedure using crude oil
washing, are to be fitted with an inert gas system complying with the requirements of 5C-1-7/25 and with
fixed tank washing machines.

23.5 Fire Main Isolation Valve

Isolation valves are to be fitted in the fire main at poop front in a protected position and on the tank deck at
intervals of not more than 40 m (131 ft) to preserve the integrity of the fire main system in case of fire or
explosion.

23.7 Fireman’s Outfits

Oil carriers are to carry two fireman’s outfits in addition to those required in 4-7-3/15.5.2(a).

25 Inert Gas System

25.1 General
The inert gas system is to be so designed and operated as to render and maintain the atmosphere of the
cargo tanks to be non-flammable at all times, except when such tanks are required to be gas free. In the
event that the inert gas system is unable to meet the operational requirement set out above and it has been
assessed that it is impractical to effect a repair, then cargo discharge, deballasting and necessary tank
cleaning should only be resumed when the “emergency conditions” laid down in the IMO documents
MSC/Circ.353 and 387 Guidelines for Inert Gas Systems are complied with.
Throughout this subsection the term “cargo tank” also includes “slop tanks”.

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25.3 Basic Requirements

The system is to be capable of:
i) Inerting empty cargo tanks by reducing the oxygen content of the atmosphere in each tank to a
level at which combustion cannot be supported;
ii) Maintaining the atmosphere in any part of any cargo tank with an oxygen content not exceeding
8% by volume and at a positive pressure at all times in port and at sea, except when it is necessary
for such a tank to be gas free;
iii) Eliminating the need for air to enter a tank during normal operations, except when it is necessary
for such a tank to be gas free;
iv) Purging empty cargo tanks of hydrocarbon gas so that subsequent gas freeing operations will at no
time create a flammable atmosphere within the tank.

25.5 System Capacity and Oxygen Content

25.5.1 Capacity
The system is to be capable of delivering inert gas to the cargo tanks at a rate of at least 125% of
the maximum rate of discharge capacity of the vessel expressed as a volume flow rate.
25.5.2 Oxygen Content
The system is to be capable of delivering inert gas with an oxygen content of not more than 5% by
volume in the inert gas supply main to the cargo tanks at any required rate of flow.

25.7 Source of Inert Gas

25.7.1 Acceptable Sources
The inert gas supply may be treated flue gas from main or auxiliary boilers. Systems using flue
gases from one or more separate gas generators or other sources or any combination thereof may
be accepted, provided that an equivalent standard of safety is achieved. All flue gas plants are to
be fitted with automatic control so that inert gas of suitable volume and quality can be delivered
upon demand under all service conditions. Systems using stored carbon dioxide are not permitted
unless the risk of ignition from the generation of static electricity by the system itself is minimized.
25.7.2 Fuel Oil Pumps for Inert Gas Generators
Two fuel oil pumps are to be fitted to the inert gas generator. Only one fuel oil pump may be
permitted on condition that sufficient spares for the fuel oil pump and its prime mover are carried
onboard to enable any failure of the fuel oil pump and its prime mover to be rectified by the
vessel’s crew.
25.7.3 Pump Certification
The fuel oil pumps serving the boiler or inert gas generator are to be certified in accordance with
4-6-1/7.3.1vi).

25.9 Flue Gas Isolating Valves

Flue gas isolating valves are to be fitted in the inert gas supply mains between the boiler uptakes and the
flue gas scrubber. These valves are to be provided with indicators to show whether they are open or shut,
and precautions are to be taken to maintain them gastight and to keep the seatings clear of soot. Arrangements
are to be made to ensure that boiler soot blowers cannot be operated when the corresponding flue gas valve
is open.

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25.11 Flue Gas Scrubber

25.11.1 General
A flue gas scrubber is to be fitted which will effectively cool the volume of gas specified in
5C-1-7/25.5 and remove solids and sulfur combustion products. The cooling water arrangements
are to be such that an adequate supply of water will always be available without interfering with
any essential services on the vessel. Provision is also to be made for an alternative supply of
cooling water.
Scrubbers, blowers, non-return devices, scrubber effluent and other drain piping, which may be
subjected to corrosive action of the gas and liquid are to be either constructed of corrosion
resistant material or lined with rubber, glass epoxy resin or equivalent coating. See ABS Guidance
Manual for Material Selection and Inspection of Inert Gas Systems 1980.
25.11.2 Filters
Filters or equivalent devices are to be fitted to minimize the amount of water carried over to the
inert gas blowers.
25.11.3 Scrubber Location
The scrubber is to be located aft of all cargo tanks, cargo pump rooms and cofferdams separating
these spaces from machinery spaces of category A.
25.11.4 Pump Certification
The cooling water pumps serving the flue gas scrubber are to be certified in accordance with
4-6-1/7.3.1vi).

25.13 Blowers
25.13.1 Number of Blowers
At least two blowers are to be fitted which together are to be capable of delivering to the cargo
tanks at least the volume of gas required by 5C-1-7/25.5. Where two blowers are fitted, the total
required gas capacity is preferably to be divided equally between the two blowers. In no case is
one blower to be less than 1/3 of the total required gas capacity.
In the system with a gas generator only, one blower may be permitted if that system is capable of
delivering the total volume of gas required by 5C-1-7/25.5 to the protected cargo tanks, provided
that sufficient spares for the blower and its prime mover are carried onboard to enable any failure
of the blower and its prime mover to be rectified by the vessel's crew.
25.13.2 Blower Piping
The inert gas system is to be so designed that the maximum pressure which it can exert on any
cargo tank will not exceed the test pressure of any cargo tank [0.24 bar (0.24 kgf/cm2, 3.5 psi)].
Suitable shut-off arrangements are to be provided on the suction and discharge connections of
each blower. Arrangements are to be provided to enable the functioning of the inert gas plant to be
stabilized before commencing cargo discharge. Oil-fired inert gas generators are to be provided
with arrangements to vent off-specification inert gas to the atmosphere, e.g., during startup or in
the event of equipment failure. If the blowers are to be used for gas freeing, their air inlets are to
be provided with blanking arrangements.
25.13.3 Blower Location
The blowers are to be located aft of all cargo tanks, cargo pump rooms and cofferdams separating
these spaces from machinery spaces of category A.

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Section 7 Cargo Oil and Associated Systems 5C-1-7

25.15 Flue Gas Leakage

25.15.1 General
Special consideration is to be given to the design and location of scrubber and blowers with
relevant piping and fittings in order to prevent flue gas leakage into enclosed spaces.
25.15.2 Leakage During Maintenance
To permit safe maintenance, an additional water seal or other effective means of preventing flue
gas leakage is to be fitted between the flue gas isolating valves and scrubber or incorporated in the
gas entry to the scrubber.

25.17 Gas Regulating Valve

25.17.1 Gas Flow Regulation
A gas regulating valve is to be fitted in the inert gas supply main. This valve is to be automatically
controlled to close, as required in 5C-1-7/25.37.3 and 5C-1-7/25.37.4. It is also to be capable of
automatically regulating the flow of inert gas to the cargo tanks unless means are provided to
automatically control the speed of the inert gas blowers required in 5C-1-7/25.13.
25.17.2 Location of Gas Regulating Valve
The gas regulating valve is to be located at the forward bulkhead of the forward-most gas safe
space through which the inert gas supply main passes. A gas safe space is a non-hazardous spaces
(see 5C-1-7/1.3.8).

25.19 Non-return Devices

25.19.1 General
At least two non-return devices, one of which is to be a water seal, are to be fitted in the inert gas
supply main, in order to prevent the return of hydrocarbon vapor to the machinery space uptakes
or to any gas safe space under all normal conditions of trim, list and motion of the vessel. They are
to be located between the gas regulating valve required by 5C-1-7/25.17 and the after-most
connection to any cargo tank or cargo pipeline.
25.19.2 Location of Non-return Devices
The non-return devices referred to in 5C-1-7/25.19.1 are to be located in the cargo area on deck.
25.19.3 Water Supply to Water Seal
The water seal is to be capable of being supplied by two separate pumps, each of which is to be
capable of maintaining an adequate supply at all times.
25.19.4 Function of Water Seal
The arrangement of the seal and its associated fittings is to be such that it will prevent backflow of
hydrocarbon vapors and will ensure the proper functioning of the seal under operating conditions.
25.19.5 Anti-freeze Arrangement for Water Seal
Provision are to be made to ensure that the water seal is protected against freezing, in such a way
that the integrity of the seal is not impaired by overheating.
25.19.6 Water Loop Protection for Gas Safe Spaces
A water loop or other approved arrangement is also to be fitted to each associated water supply
and drain pipe and each venting or pressure-sensing pipe leading to gas safe spaces. Means are to
be provided to prevent such loops from being emptied by vacuum.
25.19.7 Hydrostatic Head of Water Seal and Water Loop
The deck water seal and all loop arrangements are to be capable of preventing return of hydrocarbon
vapors at a pressure equal to the test pressure of the cargo tanks.

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25.19.8 Non-return Valve

The second device is to be a non-return valve or equivalent capable of preventing the return of
vapors or liquids and fitted forward of the deck water seal. It is to be provided with a positive
means of closure. As an alternative to a positive means of closure, an additional valve having such
means of closure may be provided forward of the non-return valve to isolate the deck water seal
from the inert gas main to the cargo tanks.
25.19.9 Venting Arrangement
As an additional safeguard against the possible leakage of hydrocarbon liquids or vapors back
from the deck main, means are to be provided to permit the section of the line between the valve
having positive means of closure referred to 5C-1-7/25.19.8 and the gas regulating valve referred
to in 5C-1-7/25.17 to be vented in a safe manner when the first of these valves is closed.

25.21 Branching of Inert Gas Main

25.21.1 General
The inert gas main may be divided into two or more branches forward of the non-return devices
required by 5C-1-7/25.19.
25.21.2 Branch Piping Isolating Valves
25.21.2(a) Oil carriers. The inert gas supply mains are to be fitted with branch piping leading to
each cargo tank. Branch piping for inert gas is to be fitted with either a stop valve or an equivalent
means of control for isolating each tank. Where stop valves are fitted, they are to be provided with
locking arrangements, which are to be under the control of a responsible officer of the vessel. The
control system operated is to provide positive indication of the operational status of such valves.
25.21.2(b) Combination carriers. In combination carriers, the arrangement to isolate the slop
tanks containing oil or oil residues from other tanks is to consist of blank flanges which will remain
in position at all times when cargoes other than oil are being carried, except as provided for in the
relevant section of IMO’s Revised Guidelines for Inert Gas Systems.
25.21.3 Overpressure and Vacuum Protection of Isolated Tanks
Means are to be provided to protect cargo tanks against the effect of overpressure or vacuum
caused by thermal variations when the cargo tanks are isolated from the inert gas mains. See also
5C-1-7/11.5.
25.21.4 Self-draining of Piping
Piping systems are to be so designed as to prevent the accumulation of cargo or water in the
pipelines under all normal conditions. See also 5C-1-7/11.7.
25.21.5 External Supply Connection
Suitable arrangements are to be provided to enable the inert gas main to be connected to an
external supply of inert gas. The arrangements are to consist of a 250 mm (10 in.) nominal pipe
size bolted flange, isolated from the inert gas main by a valve and located forward of the non-
return valve referred to in 5C-1-7/25.19.8. The design of the flange is to conform to the appropriate
Class in the Standards adopted for the design of other external connections in the vessel’s cargo
piping system.

25.23 Venting for Large Gas Volumes

The arrangements for the venting of all vapors displaced from the cargo tanks during loading and ballasting
are to comply with 5C-1-7/11.17 and are to consist of either one or more mast risers, or a number of high
velocity vents. The inert gas supply mains may be used for such venting.

25.25 Inerting, Purging or Gas-freeing of Empty Tanks

The arrangements for inerting, purging or gas freeing of empty tanks, as required in 5C-1-7/25.3, are to be
such that the accumulation of hydrocarbon vapors in pockets formed by the internal structural members in
a tank is minimized.

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 7 Cargo Oil and Associated Systems 5C-1-7

25.25.1 Position of Gas Outlet Pipe

On individual cargo tanks, the gas outlet pipe, if fitted, is to be positioned as far as practicable
from the inert gas/air inlet and in accordance with 5C-1-7/11. The inlet of such outlet pipes may
be located either at deck level or at not more than 1 m above the bottom of the tank.
25.25.2 Size of Gas Outlet Pipe
The cross sectional area of such gas outlet pipe is to be such that an exit velocity of at least 20 m/s
(66 ft/s) can be maintained when any three tanks are being simultaneously supplied with inert gas.
Their outlets are to extend not less than 2 m (6.6 ft) above deck level.
25.25.3 Blanking of Gas Outlet Pipe
Each gas outlet is to be fitted with suitable blanking arrangements.
25.25.4 Connection to Cargo Piping
25.25.4(a) Acceptable connection arrangement. If a connection is fitted between the inert gas
supply mains and the cargo piping system, arrangements are to be made to ensure an effective
isolation, having regard to the large pressure difference which may exist between the systems. This
is to consist of two shut-off valves with an arrangement to vent the space between the valves in a safe
manner or an arrangement consisting of a spool-piece with associated blanks. See 5C-1-7/Figure 1.

FIGURE 1
Connection between Inert Gas Main and Cargo Piping
Cargo Piping

Non-return
Valve

Spool Piece
Venting

Inert Gas Main

25.25.4(b) Non-return valve. The valve separating the inert gas supply main from the cargo
main and which is on the cargo main side is to be a non-return valve with a positive means of closure.

25.27 Pressure/Vacuum-breaking Devices

25.27.1 General
One or more pressure/vacuum-breaking devices are to be provided on the inert gas supply main to
prevent the cargo tanks from being subject to:
i) A positive pressure in excess of the test pressure of the cargo tank if the cargo were to be
loaded at the maximum specified rate and all other outlets were left shut; or
ii) A negative pressure in excess of 700 mm (27.5 in.) water gauge if cargo were to be discharged
at the maximum rated capacity of the cargo pumps and the inert gas blowers were to fail.
Such devices are to be installed on the inert gas main unless they are installed in the venting system
required by 5C-1-7/11.1 or on individual cargo tanks.
25.27.2 Location and Design
The location and design of the devices are to be in accordance with 5C-1-7/11.

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25.29 Instrumentation at Gas Blower Outlets

Means are to be provided for continuously indicating the temperature and the pressure of the inert gas at
the discharge side of the gas blowers, whenever the gas blowers are operating.

25.31 Monitoring of Inert Gas

25.31.1 Instrumentation at Inert Gas Supply Main
Instrumentation is to be fitted for continuously indicating and permanently recording when the
inert gas is being supplied:
i) The pressure of the inert gas supply mains forward of the non-return devices, required by
5C-1-7/25.19.1; and
ii) The oxygen content of the inert gas in the inert gas supply mains on the discharge side of
the gas blowers.
25.31.2 Cargo Control Room Displays
The devices in 5C-1-7/25.31.1 are to be placed in the cargo control room, where provided. But
where no cargo control room is provided, they are to be placed in a position easily accessible to
the officer in charge of the cargo operations.
25.31.3 Navigation Bridge and Machinery Control Room Displays
In addition, displays are to be fitted:
i) In the navigation bridge to indicate at all times the pressure referred to in 5C-1-7/25.31.1i)
and the pressure in the slop tanks of combination carriers, whenever those tanks are isolated
from the inert gas supply main; and
ii) In the machinery control room or in the machinery space to indicate the oxygen content
referred to in 5C-1-7/25.31.1ii).

25.33 Portable Detectors (2001)

Portable detectors for measuring oxygen and flammable vapor concentration in inerted atmospheres are to
be provided. This requirement may be satisfied by the detectors addressed in 5C-1-7/17.7, provided the
flammable vapor concentration detectors are capable of measuring concentrations of flammable vapors in
an inerted atmosphere as well as in air. Otherwise, two additional flammable vapor concentration detectors
capable of measuring concentrations of flammable vapors in an inerted atmosphere are to be carried
onboard. In addition, suitable arrangement are to be made on each cargo tank such that the condition of the
tank atmosphere can be determined using these portable detectors.

25.35 Calibration of Instruments

Suitable means are to be provided for the zero and span calibration of both fixed and portable gas
concentration measurement instruments, referred to in 5C-1-7/25.31 and 5C-1-7/25.33.

25.37 Alarms and Shutdowns

25.37.1 Alarms for Flue Gas Type Systems
For inert gas systems of the flue gas type, audible and visual alarms are to be provided to indicate:
i) Low water pressure or low water flow rate to the flue gas scrubber, as referred to in
5C-1-7/25.11.1;
ii) High water level in the flue gas scrubber, as referred to in 5C-1-7/25.11.1;
iii) High gas temperature, as referred to in 5C-1-7/25.29;
iv) Failure of the inert gas blowers, as referred to in 5C-1-7/25.13;
v) Oxygen content in excess of 8% by volume, as referred to in 5C-1-7/25.31.1ii);

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Section 7 Cargo Oil and Associated Systems 5C-1-7

vi) Failure of the power supply to the automatic control system for the gas regulating valve
and to the indicating devices, as referred to in 5C-1-7/25.17 and 5C-1-7/25.31.1;
vii) Low water level in the water seal, as referred to in 5C-1-7/25.19.1;
viii) Gas pressure less than 100 mm water gauge, as referred to in 5C-1-7/25.31.1i). The alarm
arrangement are to be such as to ensure that the pressure in slop tanks in combination
carriers can be monitored at all times; and
ix) High gas pressure, as referred to in 5C-1-7/25.31.1i).
25.37.2 Alarms for Inert Gas Generator Type Systems
For inert gas systems of the inert gas generator type, audible and visual alarms are to be provided
in accordance with 5C-1-7/25.37.1, plus the following:
i) Insufficient fuel oil supply;
ii) Failure of the power supply to the generator (This condition is to also automatically
shutdown the gas-regulating valve.);
iii) Failure of the power supply to the automatic control system for the generator.
In addition, the fuel oil supply to the gas generator is to be automatically shutdown in the event of
a) low water pressure (or flow) to scrubber; and b) high gas temperature.
25.37.3 Automatic Shut-down of the Inert Gas Blowers and Gas Regulating Valve
Automatic shut-down of the inert gas blowers and gas regulating valve is to be arranged on
predetermined limits being reached with respect to 5C-1-7/25.37.1i), 5C-1-7/25.37.1ii) and
5C-1-7/25.37.1iii).
25.37.4 Automatic Shut-down of the Gas Regulating Valve
Automatic shutdown of the gas regulating valve is to be arranged with respect to 5C-1-7/25.37.1iv).
25.37.5 Suspension of Cargo Tank Operations
With respect to 5C-1-7/25.37.1v), when the oxygen content of the inert gas exceeds 8% by volume,
immediate action is to be taken to improve the gas quality. Unless the quality of the gas improves,
all cargo tank operations are to be suspended so as to avoid air being drawn in to the tanks, and the
isolation valve referred to in 5C-1-7/25.19.8 is to be closed.
25.37.6 Alarms in Cargo Control Room and Machinery Space
The alarms required in 5C-1-7/25.37.1v), 5C-1-7/25.37.1vi) and 5C-1-7/25.37.1viii) are to be
fitted in the machinery space and cargo control room, where provided, but in each case, in such a
position that they are immediately received by responsible members of the crew.
25.37.7 Dry Water Seal Water Supply
As per the intent of 5C-1-7/25.37.1vii), an adequate reserve of water is to be maintained at all
times and the integrity of the arrangements to permit the automatic formation of the water seal
when the gas flow ceases is also to be maintained. The audible and visual alarm on the low level
of the water in the water seal is to operate when the inert gas is not being supplied.
25.37.8 Additional Low Inert Gas Pressure Protection
An audible alarm system independent of that required in 5C-1-7/25.37.1viii) or automatic shutdown
of cargo pumps is to be provided to operate on predetermined limits of low pressure in the inert
gas mains being reached.

25.39 Instruction Manuals

Detailed instruction manuals are to be provided onboard, covering the operations, safety and maintenance
requirements and occupational health hazards relevant to the inert gas system and its application to the
cargo tank system. The manuals are to include guidance on procedures to be followed in the event of a
fault or failure of the inert gas system. Reference is to be made to the IMO document MSC/Circ.353 and
387 Guidelines for Inert Gas Systems.

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Section 7 Cargo Oil and Associated Systems 5C-1-7

25.41 Nitrogen Generator Inert Gas Systems

25.41.1 Application
The requirements of 5C-1-7/25.41 apply where inert gas is produced by separating air into its
component gases by passing compressed air through a bundle of hollow fibers, semi-permeable
membranes or absorber materials. Where such systems are provided in place of the boiler flue gas
or oil-fired inert gas generators, the following requirements are also applicable for the piping
arrangements, alarms and instrumentation downstream of the gas generator:

5C-1-7/25.17.1 5C-1-7/25.17.2 5C-1-7/25.21 5C-1-7/25.23 5C-1-7/25.25

5C-1-7/25.27 5C-1-7/25.31.1i) 5C-1-7/25.31.2 5C-1-7/25.31.3 5C-1-7/25.33
5C-1-7/25.35 5C-1-7/25.37.1vi) 5C-1-7/25.37.1viii) 5C-1-7/25.37.1ix) 5C-1-7/25.37.3
5C-1-7/25.37.4 5C-1-7/25.37.6 5C-1-7/25.37.8 5C-1-7/25.39

25.41.2 Nitrogen Generator

25.41.2(a) Capacity. A nitrogen generator consists of a feed air treatment system and any
number of membrane or absorber modules in parallel necessary to meet the required capacity which
is to be at least 125% of the maximum discharge capacity of the vessel expressed as a volume.
25.41.2(b) Gas specification. The nitrogen generator is to be capable of delivering high purity
nitrogen with oxygen content not exceeding 5% by volume. The system is to be fitted with
automatic means to discharge “off-spec” gas to the atmosphere during start-up and abnormal operation.
The block and bleed arrangement indicated in 5C-1-7/25.41.4 is not to be used for this purpose.
25.41.2(c) Air compressors. The system is to be provided with two air compressors. The total
required capacity of the system is preferably to be divided equally between the two compressors,
and in no case is one compressor to have a capacity less than 1/3 of the total capacity required.
Only one air compressor may be accepted, provided that sufficient spares for the air compressor
and its prime mover are carried onboard to enable their failure to be rectified by the vessel's crew.
25.41.2(d) Feed air treatment. A feed air treatment system is to be fitted to remove free water,
particles and traces of oil from the compressed air, and to preserve the specification temperature.
25.41.2(e) Nitrogen receiver. Where fitted, a nitrogen receiver/buffer tank may be installed in a
dedicated compartment or in the separate compartment containing the air compressor and the
generator or may be located in the cargo area. Where the nitrogen receiver/buffer tank is installed
in an enclosed space, the access is to be arranged only from the open deck and the access door is
to open outwards. Permanent ventilation and alarm are to be fitted as in 5C-1-7/25.41.3.
In order to permit maintenance, means of isolation are to be fitted between the generator and the
receiver.
25.41.2(f) Enriched gases. The oxygen-enriched air from the nitrogen generator and the
nitrogen-product enriched gas from the protective devices of the nitrogen receiver are to be
discharged to a safe location on the open deck.
25.41.3 Location of Installation
The air compressor and the nitrogen generator may be installed in the engine room or in a separate
compartment. Where a separate compartment is provided, it is to be:
• Treated as ‘other machinery spaces’ with respect to fire protection,
• Positioned outside the cargo area,
• Fitted with an independent mechanical extraction ventilation system providing at least six (6)
air changes per hour,
• Fitted with a low oxygen alarm,
• Arranged with no direct access to accommodation spaces, service spaces and control stations.

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Section 7 Cargo Oil and Associated Systems 5C-1-7

25.41.4 Non-return Devices (2011)

At least two non-return devices are to be fitted in the inert gas supply main and located in the cargo
area on deck. One of the non-return devices is to be of the double block and bleed arrangement
(two shut-off valves in series with a venting valve in between) for which the following conditions
apply:
i) The operation of the valve is to be automatically executed. Signal(s) for opening/closing
are to be taken from the process directly (e.g., inert gas flow or differential pressure).
ii) Alarm for faulty operation of the valves is to be provided (e.g., the operation of “blower
stop” and “supply valve(s) open” is an alarm condition).
iii) Upon loss of power, the block valves are to automatically close and the bleed valve is to
automatically open.
The second non-return device is to be equipped with positive means of closure.
25.41.5 Instrumentation
25.41.5(a) Compressed air. Instrumentation is to be provided for continuously indicating the
temperature and pressure of air:
i) At the discharge side of the compressor,
ii) At the entrance side of the nitrogen generator.
25.41.5(b) Inert gas (2007). Instrumentation is to be fitted for continuously indicating and
permanently recording the oxygen content of the inert gas downstream the nitrogen generator
when inert gas is being supplied. This instrumentation is to be placed in the cargo control room
where provided. Where no cargo control room is provided, they are to be placed in a position
easily accessible to the officer in charge of the cargo operation.
25.41.5(c) Alarms. Audible and visual alarms are to be provided to indicate:
i) Low air pressure from compressor, as referred to in 5C-1-7/25.41.5(a)i);
ii) High air temperature, as referred to in 5C-1-7/25.41.5(a)i);
iii) High condensate level at automatic drain of water separator, as referred to in
5C-1-7/25.41.2(d),
iv) Failure of electrical heater, if fitted,
v) Oxygen content in excess of that specified in 5C-1-7/25.41.2(b),
vi) Failure of power supply to the instrumentation, as referred to in 5C-1-7/25.41.5(b).
These alarms are to be fitted in the machinery space and cargo control room, where provided, but
in each case, in such a position that they are immediately received by responsible members of the
crew.
25.41.6 Automatic Shutdown
Automatic shutdown of the system is to be arranged for the alarm conditions in 5C-1-7/25.41.5(c)i)
through 5C-1-7/25.41.5(c)v).
25.41.7 Non-mandatory Systems
Where a nitrogen inerting system is installed on an oil carrier which is not required to be fitted
with an inert gas system (i.e., oil carriers of less than 20,000 tonnes deadweight not fitted with
crude oil washing systems), it is to comply with the requirements in 5C-1-7/25.41, except for:
• 5C-1-7/25.41.1;
• 5C-1-7/25.41.2(a) and 5C-1-7/25.41.2(c); and
• where the connections to the cargo tanks, hold spaces or cargo piping are not permanent, the
non-return devices required by 5C-1-7/25.41.4 may be substituted by two non-return valves.

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 7 Cargo Oil and Associated Systems 5C-1-7

27 Fixed Deck Foam System

27.1 General
The arrangements for providing foam are to be capable of delivering foam to the entire cargo tank deck
area as well as into any cargo tank, the deck of which has been ruptured.
The system is to be capable of simple and rapid operation. The main control station for the system is to be
suitably located outside of the cargo tank area, adjacent to the accommodation spaces and readily accessible
and operable in the event of fire in the areas protected.
Reference is to be made to IMO MSC/Circ.582 Guidelines for the performance and testing
criteria and surveys of low-expansion foam concentrates for fixed fire extinguishing system.

27.3 Foam Solution Supply Rate

The rate of supply of foam solution is to be not less than the greatest of the following:
i) 0.6 liters/min/m2 (0.015 gal/min/ft2) of the cargo deck area, where cargo deck area means the
maximum breadth of the vessel multiplied by the total longitudinal extent of the cargo tank spaces,
ii) 6 liters/min/m2 (0.15 gal/min/ft2) of the horizontal sectional area of the single tank having the
largest such area; or
iii) 3 liters/min/m2 (0.075 gal/min/ft2) of the area protected by the largest monitor, such area being
entirely forward of the monitor, but not less than 1,250 liters per minute.

27.5 Foam Concentrate Quantity

Sufficient foam concentrate is to be supplied to ensure at least:
• 20 minutes of foam generation in oil carriers fitted with an inert gas installation; or
• 30 minutes of foam generation in oil carriers not fitted with an inert gas installation;
when using solution rates stipulated in 5C-1-7/27.3i), 5C-1-7/27.3ii) or 5C-1-7/27.3iii), whichever is the
greatest.
The foam expansion ratio (i.e., the ratio of the volume of foam produced to the volume of the mixture of
water and foam-making concentrate supplied) is not to generally exceed 12:1.
Where systems essentially produce low expansion foam but at an expansion ratio slightly in excess of 12:1,
the quantity of foam solution available is to be calculated as for 12:1 expansion ratio systems.
When medium expansion ratio foam (between 50:1 and 150:1 expansion ratio) is employed the application
rate of the foam and the capacity of a monitor installation are to be submitted for consideration in each case.

27.7 Required Foam Monitor and Foam Applicator Capacities

Foam from the fixed foam system is to be supplied by means of monitors and foam applicators. At least
50% of the foam solution supply rate required in 5C-1-7/27.3i) and 5C-1-7/27.3ii) is to be delivered from
each monitor.
On oil carriers of less than 4,000 tonnes deadweight, foam applicators may be installed in lieu of foam
monitors. In which case, the capacity of each applicator is to be at least 25% of the foam solution supply
rate required in 5C-1-7/27.3i) or 5C-1-7/27.3ii).

27.9 Minimum Foam Monitor Capacity

The number and position of monitors are to be such as to comply with 5C-1-7/27.1. The capacity of any
monitor is to be at least 3 liters/min (0.075 gpm) of foam solution per square meter of deck area protected,
such area being entirely forward of the monitor. Such capacity is not to be less than 1250 liters/min (330 gpm).
The distance from the monitor to the farthest extremity of the protected area forward of that monitor is not
to be more than 75% of the monitor throw in still air conditions.

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Section 7 Cargo Oil and Associated Systems 5C-1-7

27.11 Installation at Poop Front

A monitor and hose connection for a foam applicator are to be situated both port and starboard at the front
of the poop or accommodation spaces facing the cargo tanks deck.
On oil carriers of less than 4,000 tonnes deadweight, a hose connection for a foam applicator is to be situated
both port and starboard at the front of the poop or accommodation spaces facing the cargo tanks deck.

27.13 Use and Minimum Capacity of Foam Applicators

Applicators are to be provided to ensure flexibility of action during fire-fighting operations and to cover
areas screened from the monitors. The capacity of any applicator is to be not less than 400 liters/min (106
gpm) and the applicator throw in still air conditions is to be not less than 15 meters. The number of
applicators provided is to be not less than four. The number and disposition of foam main outlets is to be
such that foam from at least two applicators can be directed on to any part of the cargo tanks deck area.

27.15 Foam Main and Fire Main Isolation Valves

Valves are to be provided in the foam main, and in the fire main when this is an integral part of the deck
foam system, immediately forward of any monitor position to isolate damaged sections of these mains.

27.17 Simultaneous Operation

Operation of a deck foam system at its required output is to permit the simultaneous use of the minimum
required number of jets of water at the required pressure from the fire main.

27.19 Bow or Stern Loading and Unloading (2003)

Ships fitted with bow or stern loading and unloading arrangements are to be provided with one additional
foam monitor meeting the requirements of 5C-1-7/27.7 and one additional applicator meeting the requirements
of 5C-1-7/27.13. The additional monitor is to be located to protect the bow or stern loading and unloading
arrangements. The area of the cargo line forward or aft of the cargo block area is to be protected by the
above-mentioned applicator.

29 Cargo Pump Room Protection

29.1 Fixed Fire Extinguishing System

Each pump room is to be provided with one of the following fixed fire-extinguishing systems operated
from a readily accessible position outside the pump room:
i) A CO2 system complying with the provisions of 4-7-3/3 (or FSS Code Chapter 5) and with the
following:
• The alarm referred to in 4-7-3/3.1.5 (or FSS Code Chapter 5.2.1.3.2) is to be safe for use in a
flammable cargo vapor/air mixture (see 5C-1-7/Table 1, item c4). The electrical alarm actuating
mechanism is to be located outside the pump room. Pneumatic alarms are also acceptable;
where fitted, air, and not CO2, is to be used for testing of pneumatic alarms;

• A notice is to be exhibited at the controls stating that due to the electrostatic ignition hazard,
the system is to be used only for fire extinguishing and not for inerting purposes.
ii) A high-expansion foam system complying with the provisions of 4-7-3/5.1 (or FSS Code Chapter 6),
provided that the foam concentrate supply is suitable for extinguishing fires involving the cargo
carried.
iii) A fixed pressure water-spray system complying with the provisions of 4-7-3/7 (or FSS Code
Chapter 7).

29.3 Required Quantity of Fire-extinguishing Medium

Where the fire-extinguishing medium used in the cargo pump room system is also used in systems serving
other spaces, the quantity of medium provided or its delivery rate need not be more than the maximum
required for the largest compartment.

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Section 7 Cargo Oil and Associated Systems 5C-1-7

31 Electrical Installations

31.1 Application (2007)

i) These requirements are additional to, or modifying those of, Section 4-8-1 through Section 4-8-4,
as appropriate.
ii) These requirements address electrical safety associated with hazardous areas of oil carriers.
iii) Oil carriers subject to SOLAS are to comply with the requirements of IEC 60092-502 (1999)
“Electrical Installations in Ships – Tankers – Special Features” in accordance with Chapter II-1,
Regulation 45.11 of the 2004 Amendments to SOLAS. Oil carriers subject to SOLAS that comply
with the electrical safety requirements of IEC 60092-502 (1999), associated with hazardous areas,
will not be required to meet 5C-1-7/31.5, 5C-1-7/31.7, 5C-1-7/31.9, 5C-1-7/Table 1 and 5C-1-7/31.11.

31.3 Limited Use of Earthed Distribution Systems

An earthed distribution system is not to be used, except for the following applications:
i) Earthed intrinsically-safe circuits.
ii) Control circuits and instrumentation circuits where technical or safety reasons preclude the use of
a system without an earthing connection, provided the current in the hull is limited to 5 A or less
in both normal and fault conditions.
iii) Limited and locally earthed systems, provided that any possible resultant earth current does not
flow directly through any hazardous areas.
iv) Alternating-current power networks of 1 kV (rms, line to line) and over, provided that any possible
resultant earth current does not flow directly through any hazardous areas.

31.5 Hazardous Areas

The following are to be regarded as hazardous areas (see also 5C-1-7/Figure 2).
31.5.1 Enclosed Spaces
i) Cargo tanks and cargo piping.
ii) Cofferdams, ballast and peak tanks; underdeck walkways and duct keel; and trunks:
• which are adjacent to cargo tanks;
• through which cargo piping passes; or
• which are served by piping either (1) connected to cargo oil system, (2) passed through
cargo tank, or (3) also serving spaces located immediately adjacent to cargo tanks.
iii) Cargo pump rooms.
iv) Compartments for storage of cargo hoses.
v) Where permitted (by SOLAS Reg. II-2/4.5), any enclosed or semi-enclosed space:
• immediately above cargo tanks,
• aft or forward of all cargo tanks but having bulkheads immediately above and in-line
with cargo tank end bulkheads (unless the corner-to-corner common boundary is
eliminated by means of a diagonal plate welded across the corner),
• immediately above cargo pump room (unless separated by a gastight bulkhead and
suitably mechanically ventilated), or
• immediately above vertical cofferdams, ballast tanks, fuel oil tanks, etc. adjacent to
cargo tanks (unless separated by a gastight deck and suitably mechanically ventilated).
vi) Enclosed and semi-enclosed spaces having a direct access or opening into any space
described in 5C-1-7/31.5.1ii) through 5C-1-7/31.5.1v).
vii) Enclosed or semi-enclosed spaces having an opening (door, ventilation port, etc.) within
the hazardous areas defined in 5C-1-7/31.5.2.

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Section 7 Cargo Oil and Associated Systems 5C-1-7

31.5.2 Open Deck Spaces (2006)

i) Areas on open deck over all cargo tanks (including all ballast tanks within cargo tank
area) and to the full breadth of the vessel plus 3 m (10 ft) fore and aft on open deck, up to
a height of 2.4 m (8 ft) above the deck.
ii) Areas on open deck within 3 m (10 ft) of openings to the spaces in 5C-1-7/31.5.1. These
include, but not limited to, the following:
• Any opening (e.g., tank hatch, tank ullage port, etc.) of cargo tank;
• Any opening (e.g., hatch, air vent pipe head, sounding pipe head, etc.) of cofferdams,
ballast tanks, peak tanks, fuel oil tanks, etc., which are adjacent to cargo tanks.
• Cargo manifold valves, cargo valves, cargo pipe flanges and similar pipe fittings.
• Cargo pump room entrances and cargo pump room ventilation openings.
iii) Areas on open deck in way of cargo tank vents:
• within 3 m (10 ft) measured spherically with outlet as center;
• during the flow of small volume of vapor, air or inert gas mixtures caused by thermal
variations in cargo tanks, spaces up to 5 m (16.5 ft), measured spherically with outlet
as center, from pressure/vacuum valves; and
• during the flow of large volume of vapor, air or inert gas mixtures when cargo loading
and ballasting or when discharging, spaces up to 10 m (33 ft), measured cylindrically
with vertical vent pipe as axis and extending vertically without limit, from free flow
vents and high velocity vents.
(2006) Note: Anchor windlass and chain locker openings are not to be located within the above areas
since these constitute an ignition hazard.
iv) Areas on open deck in way of cargo manifold valve spillage containment coaming and
other coamings intended to keep spillage from accommodation and service spaces:
• area within the coaming, and
• areas within 2.4 m (8 ft) above the deck up to 3 m (10 ft) from the edge of the coaming.
31.5.3 Forepeak Tank and Spaces Above Forepeak Tank (2010)
31.5.3(a) Forepeak tank adjacent to cargo tank. Where the forepeak tank is adjacent to a cargo tank,
i) The forepeak tank is to be considered as hazardous [see 5C-1-7/31.5.1ii)],
ii) Sounding and vent piping arrangements for the forepeak tank are to lead to the open deck
and are to be located 3 m (10 ft) away from sources of ignition [see 5C-1-7/31.5.2ii)],
iii) A permanent arrangement leading from the forepeak tank to the open deck is to be
provided to allow measurement of flammable gas concentrations within the forepeak tank
by a suitable portable instrument,
iv) Any access opening to the forepeak tank must be direct from the open deck. Alternatively,
indirect access from the open deck to the fore peak tank through an enclosed space may
be accepted provided the arrangements meet one of the following two cases.
1. In case the enclosed space is separated from the cargo tanks by cofferdams and
the access is through a gas tight bolted manhole located in the enclosed space,
then a warning sign is to be provided at the manhole. The warning sign is to
state that the manhole may only be opened after the forepeak tank has been
proven to be gas free or after isolation of all electrical equipment within the
enclosed space which is not certified safe.
2. In case the enclosed space has a common boundary with the cargo tanks and is
therefore hazardous, then the enclosed space is to be capable of being well
ventilated at a rate of at least 6 air changes per hour.
See also 5C-1-7/31.5.1.

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31.5.3(b) Forepeak tank not adjacent to cargo tank. Where the forepeak tank is not adjacent to a
cargo oil tank, but is served by ballast piping which also serves other ballast tanks within the cargo
area, the requirements in 5C-1-7/31.5.3(a) are applicable.

FIGURE 2
Hazardous Areas on Open Deck
3m
5m
During flow of Open Deck
small volume
3m During cargo loading and
ballasting and discharging

3m 3m
10 m 10 m 3m

2.4 m 2.4 m 2.4 m

3m 3m

Coaming in way Vent Stack 3m

P/V Vent Hatchway
of cargo manifold (High velocity valve
or free flow)
Cargo Tank

31.7 Air Locks

Enclosed and semi-enclosed spaces, other than machinery spaces of category A, having an access or opening
into hazardous areas [see 5C-1-7/31.5.1vi) and 5C-1-7/31.5.1vii)], need not be regarded as hazardous areas
themselves provided the access is through a double door air lock of either type described below. Openings
to machinery space of category A are to be located away from hazardous areas.
31.7.1 Type 1 Air Lock
31.7.1(a) Doors. The air-lock is to consist of two gas-tight steel doors of the self closing type,
with no hold-back arrangement, spaced at least 1.5 m (5 ft) but not more than 2.5 m (8 ft) apart,
and the space is provided with mechanical ventilation.
31.7.1(b) Relative pressurization. The non-hazardous space is to be maintained at overpressure
relative to the external hazardous area. The relative overpressure or air flow is to be continuously
monitored and so arranged that in the event of ventilation failure, an audible and visual alarm is
given at a manned control station and the electrical supply to all equipment (not of the certified
safe type) is to be automatically disconnected. A time delay on the disconnect will be considered
where deemed necessary.
31.7.1(c) Safety precautions. Machinery necessary for propulsion and maneuvering, anchoring
and mooring, as well as the emergency generator and emergency fire pump, where the shutdown
of which could in itself introduce a hazard, is not to be located in spaces protected by a Type 1 air
lock.
31.7.2 Type 2 Air Lock
31.7.2(a) Doors. The air lock is to consist of two gas-tight steel doors of self closing type, with
no hold-back arrangement, spaced at least 1.5 m (5 ft) but not more than 2.5 m (8 ft) apart.
31.7.2(b) Relative pressurization. The non-hazardous space and the air lock are to be maintained
at overpressure relative to the external hazardous area by independent mechanical ventilation
systems arranged such that a single failure will not result in the simultaneous loss of overpressure
in both the non-hazardous space and the air-lock. Failure of either ventilation system is to be alarmed
at a manned control station.

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31.9 Electrical Equipment Permitted in Hazardous Areas

Electrical equipment and its wiring are not to be installed in any hazardous areas unless essential for
operation purposes. Electrical equipment intended for installation in hazardous areas is to be of the
certified safe type and is to be selected in accordance with 5C-1-7/Table 1, based on the class of hazardous
area at its location of installation.

TABLE 1
Electrical Equipment in Hazardous Areas of Oil Carriers
Hazardous Area Acceptable Electrical Equipment
Cargo tanks and cargo piping, a1 Ex ia intrinsically-safe apparatus.
5C-1-7/31.5.1i)
Cofferdams, ballast tanks, peak tanks, b1 Ex ia intrinsically-safe apparatus.
5C-1-7/31.5.1ii) b2 Transducers for depth sounding or speed log; or electrodes for impressed
current system, subject to installation requirements of 5C-1-7/31.13.
Cargo pump rooms, c1 Intrinsically-safe apparatus.
5C-1-7/31.5.1iii) c2 Electrical devices as described in item b2
c3 Explosion-proof lighting fixtures.
c4 Explosion proof fire extinguishing system alarm, general alarm and
communication.
c5 Through-run of cables in extra-heavy pipe, see 5C-1-7/31.15.3.
Compartments for cargo hoses, and d1 Intrinsically-safe apparatus.
enclosed or semi-enclosed spaces above d2 Explosion-proof type lighting fixtures
cargo tanks,
5C-1-7/31.5.1iv) & 5C-1-7/31.5.1v). d3 Through-runs of cable.
Enclosed or semi-enclosed spaces having e1 Intrinsically-safe apparatus and explosion proof equipment.
opening to hazardous areas, e2 Electrical devices as described in b2
5C-1-7/31.5.1vi) and 5C-1-7/31.5.1vii).
e3 Through-run of cable
Areas on open deck as defined in f1 Explosion-proof, intrinsically-safe, increased safety or pressurized
5C-1-7/31.5.2 equipment with enclosures suitable for use on open deck.
f2 Through-runs of cables with mechanical protection, see 5C-1-7/31.11.
Notes
1 Intrinsically safe refers to Ex ia and Ex ib, except where specified otherwise.
2 Explosion proof refers to Ex d IIA T3.
3 Increased safety refers to Ex e IIA T3.
4 Pressurized or purged Ex p may substitute for 2 and 3 above.

31.11 Cable Installation in Hazardous Areas

All cables installed within the hazardous areas are to be provided with metallic braiding or metallic armoring,
or to be of mineral-insulated copper or stainless steel sheathed type. A non-metallic impervious sheath is to
be applied over the metallic braiding, armoring or sheathing for cables installed in locations subject to corrosion.
Cables installed on open deck or on fore and aft gangways are, in addition, to be protected against mechanical
damage (see 4-8-4/21.15.2). Cables and protective supports are to be so installed as to avoid strain or
chafing and, for long runs of cables, due allowance made for the effects of expansion/contraction or working
of the hull.

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31.13 Echo Sounder; Speed Log; Impressed Current System (2005)

Hull fittings penetrating the shell and containing transducers for depth sounding or speed log devices, or
containing terminals for anodes or electrodes of impressed current cathodic protection system are not to be
installed in cargo tanks. However, they may be installed in hazardous areas, such as cofferdams adjacent to
cargo tanks, as permitted by 5C-1-7/Table 1, provided all of the following are complied with:
i) Hull fittings containing terminals or shell-plating penetrations are to be housed within a gas-tight
enclosure and are not to be located adjacent to cargo tank bulkheads.
ii) The box containing actual electrical connection of the cable, such as a terminal box or junction
box, is to be filled with insulating material, such as silicon grease, silicon sealing or equivalent
and also is to be of gastight construction.
iii) All associated cables passing through these spaces are to be installed in steel pipes with at least
extra-heavy wall thickness with all joints welded and with corrosion-resistant coating.
iv) Cable gland with gastight packing is to be provided for the cable at both ends of the cable conduit pipe.
v) Cable inside of the vertical cable conduit pipe is to be suitably supported, e.g., by sand-filling or
by strapping to a support-wire. Alternatively, the cable inside of the vertical conduit pipe may be
accepted without provided support if the mechanical strength of the cable is sufficient to prevent
cable damage due to the cable weight within the conduit pipe under continuous mechanical load.
Supporting documentation is to be submitted to verify the mechanical strength of the cable with
respect to the cable weight inside of the conduit.

31.15 Cargo Oil Pump Room

31.15.1 Ventilation and Gas Detection
Ventilation arrangements of and the provision of a gas detection system in the cargo pump room
are to be in accordance with 5C-1-7/17.1.
31.15.2 Lighting
31.15.2(a) Lighting fitted outside the pump room. As far as practicable, lighting fixtures for the
pump-room are to be permanently wired and fitted outside of the pump room. Pump rooms
adjacent to engine rooms or similar safe spaces may be lighted through substantial glass lenses
permanently fitted in the bulkhead or deck. The construction of the glass lens port is to be as follows:
• Capable of maintaining watertight and gastight integrity of the bulkhead and deck.
• Suitably protected from mechanical damage.
• Provided with a steel cover capable of being closed and secured on the side of the safe space.
• Both the glass lens and its sealing arrangement will not be impaired by working of the hull.
• Structural strength of the pierced bulkhead or deck is suitably reinforced. See 5C-1-1/5.11 and
5C-2-1/5.5.
31.15.2(b) Lighting fitted inside the pump room. As an alternative to 5C-1-7/31.15.2(a), certified
safe lighting fixtures (see 5C-1-7/Table 1) may be installed in the pump room, provided they are
wired with moisture-resisting jacketed (impervious-sheathed) and armored or mineral-insulated
metal-sheathed cable. Lighting circuits are to be so arranged that the failure of any one branch
circuit will not leave the pump room in darkness. All switches and protective devices are to be
located outside the pump room. See also 4-8-4/27.11 for lighting circuits in hazardous areas.
31.15.2(c) Lighting/Ventilation Interlock. (1 July 2002) Lighting in cargo pump rooms, except
emergency lighting, is to be interlocked with the ventilation system such that the ventilation
system is to be in operation when switching on the lighting. Failure of the ventilation system is not
to cause the lighting to go out.
31.15.3 Cables Passing Through Pump Room
Where it is necessary for cables, other than intrinsically safe circuits and that supplying lighting
fixtures in pump room, to pass through cargo pump rooms, they are to be installed in extra-heavy
steel pipes, or equivalent.

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Section 7 Cargo Oil and Associated Systems 5C-1-7

31.17 Pipe Tunnel or Duct Keel

31.17.1 Ventilation and Gas Detection
Pipe tunnels, duct keels and similar spaces are to be provided with a ventilation system (see
5C_1-7/17.5.1) and a gas detection system (see 5C-1-7/17.5.2).
31.17.2 Lighting
Where a permanent lighting system is installed in enclosed spaces such as pipe tunnels, double
bottoms, or duct keels, it is to be in accordance with 5C-1-7/31.15.2. The switches are to be
accessible to authorized personnel only.

33 Integrated Cargo and Ballast Systems (2004)

33.1 Application
The following requirements are applicable to integrated cargo and ballast systems installed on tankers (i.e.,
cargo ships constructed primarily to carry liquid cargo in bulk) regardless of the flash point of the cargoes.
The integrated cargo and ballast system means any integrated hydraulic and/or electric system used to
drive both cargo and ballast pumps (including active control and safety systems but excluding passive
components, e.g., piping).

33.3 Functional Requirements

The operation of cargo and/or ballast systems may be necessary, under certain emergency circumstances or
during the course of navigation, to enhance the safety of tankers. As such, measures are to be taken to
prevent cargo and ballast pumps becoming inoperative simultaneously due to a single failure in the
integrated cargo and ballast system, including its control and safety systems.

33.5 Design Features

The following design features are to be fitted:
i) The emergency stop circuits of the cargo and ballast systems are to be independent from the
circuits for the control systems. A single failure in the control system circuits or the emergency
stop circuits is not to render the integrated cargo and ballast system inoperative.
ii) Manual emergency stops of the cargo pumps are to be arranged in such a way that they do not
cause the ballast pump power pack to stop and thus make the ballast pumps inoperable.
iii) The control systems are to be provided with backup power supply, which may be satisfied by a
duplicate power supply from the main switchboard. The failure of any power supply is to provide
audible and visible alarm activation at each location where the control panel is fitted.
iv) In the event of failure of the automatic or remote control systems, a secondary means of control is
to be made available for the operation of the integrated cargo and ballast system. This is to be
achieved by manual overriding and/or redundant arrangements within the control systems.

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PART Appendix 1: Guide for Fatigue Strength Assessment of Tankers

5C
CHAPTER 1 Vessels Intended to Carry Oil in Bulk (150 meters
(492 feet) or more in Length)

APPENDIX 1 Guide for Fatigue Strength Assessment of

Tankers

1 General

1.1 Note
This Guide provides a designer-oriented approach to fatigue strength assessment which may be used for
certain structural details in lieu of more elaborate methods such as spectral fatigue analysis. The term
“assessment” is used here to distinguish this approach from the more elaborate analysis.
The criteria in this Guide are developed from various sources, including the Palmgren-Miner linear
damage model, S-N curve methodologies, a long-term environment data of the North-Atlantic Ocean
(Walden’s Data), etc., and assume workmanship of commercial marine quality acceptable to the Surveyor.
The capacity of structures to resist fatigue is given in terms of permissible stress range to allow designers
the maximum flexibility possible.
While this is a simplified approach, a good amount of effort is still required in applying these criteria to the
actual design. For this reason, PC-based software has been developed and is available to the clients.
Interested parties are kindly requested to contact the nearest ABS plan approval office for more
information.

1.3 Applicability (1995)

The criteria in this Guide are specifically written for tankers to which Part 5C, Chapter 1 is applicable.

1.5 Loadings (1995)

The criteria have been written for ordinary wave-induced motions and loads. Other cyclic loadings, which
may result in significant levels of stress ranges over the expected lifetime of the vessel, are also to be
considered by the designer.
Where it is known that a vessel will be engaged in long-term service on a route with a more severe
environment (e.g., along the west coast of North America to Alaska), the fatigue strength assessment
criteria in this Guide are to be modified, accordingly.

1.7 Effects of Corrosion (1995)

To account for the mean wastage throughout the service life, the total stress range calculated using the net
scantlings (i.e., deducting nominal design corrosion values, see 5C-1-2/Table 1) is modified by a factor Cf
See 5C-1-A1/9.1.1.

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Appendix 1 Guide for Fatigue Strength Assessment of Tankers 5C-1-A1

1.9 Format of the Criteria (1995)

The criteria in this Guide are presented as a comparison of fatigue strength of the structure (capacity) and
fatigue inducing loads (demands), as represented by the respective stress ranges. In other words, the
permissible stress range is to be not less than the total stress range acting on the structure.
5C-1-A1/5 provides the basis to establish the permissible stress range for the combination of the fatigue
classification and typical structural joints of tankers. 5C-1-A1/7 presents the procedures to be used to
establish the applied total stress range. 5C-1-A1/11 provides typical stress concentration factors (SCFs)
and guidelines for direct calculation of the required SCFs. 5C-1-A1/13 provides the guidance for
assessment of stress concentration factors and the selection of compatible S-N data where a fine mesh
finite element approach is used.

3 Connections to be Considered for the Fatigue Strength Assessment

3.1 General (1995)

These criteria have been developed to allow consideration of a broad variation of structural details and
arrangements, so that most of the important structural details anywhere in the vessel can be subjected to an
explicit (numerical) fatigue assessment using these criteria. However, where justified by comparison with
details proven satisfactory under equal or more severe conditions, an explicit assessment can be exempted.

3.3 Guidance on Locations (1995)

As a general guidance for assessing fatigue strength for a tanker, the following connections and locations
should be considered:
3.3.1 Connections of Longitudinal Stiffeners to Transverse Web/Floor and to Transverse Bulkhead
3.3.1(a) Two (2) to three (3) selected side longitudinals in the region from the 1.1 draft to about
1/ draft in the midship region and also in the region between 0.15L and 0.25L from F.P.,
3
respectively
3.3.1(b) One (1) to two (2) selected longitudinals from each of the following groups:
• Deck longitudinals, bottom longitudinals, inner bottom longitudinals and longitudinals on side
longitudinal bulkheads
• One longitudinal on each of the longitudinal bulkheads within 0.1D from the deck is to be
included
For these structural details, the fatigue assessment is to be first focused on the flange of the
longitudinal at the rounded toe welds of attached flat bar stiffeners and brackets, as illustrated for
Class F item 2) and Class F2 item 1) in 5C-1-A1/Table 1.
Then, the critical spots on the web plate cut-out, on the lower end of the stiffener as well as the weld
throat are also to be checked for the selected structural detail. For illustration, see 5C-1-A1/11.3.1
and 5C-1-A1/11.3.2(a), 5C-1-A1/11.3.2(b) and 5C-1-A1/11.3.2(c).
Where the longitudinal stiffener end bracket arrangements are different on opposing sides of a
transverse web, both configurations are to be checked.
3.3.2 Shell, Bottom, Inner Bottom or Bulkhead Plating at Connections to Webs or Floors (for Fatigue
Strength of Plating)
3.3.2(a) One (1) to two (2) selected locations of side shell plating near the summer LWL amidships
and between 0.15L and 0.25L from F.P. respectively
3.3.2(b) One (1) to two (2) selected locations in way of bottom and inner bottom amidships
3.3.2(c) One (1) to two (2) selected locations of lower strakes of side longitudinal bulkhead amidships

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3.3.3 Connections of the Slope Plate to Inner Bottom and Side Longitudinal Bulkhead Plating at the
Lower Cargo Tank Corners
One selected location amidships at transverse web and between webs, respectively
For this structural detail, the value of fR, the total stress range as specified in 5C-1-A1/9.1, is to be
determined from fine mesh F.E.M. analyses for the combined load cases, as specified for Zone B
in 5C-1-A1/7.5.2.
3.3.4 End bracket Connections for Transverses and Girders
One (1) to two (2) selected locations in the midship region for each type of bracket configuration
3.3.5 Other Regions and Locations
Other regions and locations, highly stressed by fluctuating loads, as identified from structural
analysis.

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TABLE 1
Fatigue Classification for Structural Details (1995)
Long-term
Distribution Permissible
Parameter Stress Range
Class
Designation Description γ kgf/mm2
B Parent materials, plates or shapes as-rolled or drawn, with no flame-cut 0.7 92.2*
edges 0.8 75.9
0.9 64.2
1.0 55.6
C 1) Parent material with automatic flame-cut edges 0.7 79.2
2) Full penetration seam welds or longitudinal fillet welds made by an 0.8 63.9
automatic submerged or open arc process, and with no stop-start 0.9 53.3
positions within the length
1.0 45.7
D 1) Full penetration butt welds between plates of equal width and 0.7 59.9
thickness made either manually or by an automatic process other than 0.8 47.3
submerged arc, from both sides, in downhand position
0.9 38.9
2) Welds in C-2) with stop-start positions within the length
1.0 32.9
E 1) Full penetration butt welds made by other processes than those 0.7 52.8
specified under D-1) 0.8 41.7
2) Full penetration butt welds made from both sides between plates of 0.9 34.2
unequal widths machined to a smooth transition with a slope not more
than 1 in 4. Plates of different thickness are to be likewise machined 1.0 29.0
with a slope not more than 1 in 3, unless a transition within the weld
bead is approved.

2a 2b
E
4 1
TAPER
E
1 3
TAPER

3) Welds of brackets and stiffeners to web plate of girders

*1) The permissible stress range cannot be taken greater than two times the specified minimum tensile strength of the
material.
2) To obtain the permissible stress range in SI and U.S. Units, the conversion factors of 9.807 (N/mm2) and 1422 (lbf/in2),
respectively, may be used.

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TABLE 1 (continued)
Fatigue Classification for Structural Details (1995)
Long-term
Distribution Permissible
Parameter Stress Range
Class
Designation Description γ kgf/mm2
F 1) Full penetration butt welds made on a permanent backing strip 0.7 44.7
between plates of equal width/thickness or between plates of unequal 0.8 35.3
width/thicknesse, as specified in E-2.
0.9 29.0
2) Rounded fillet welds as shown below
1.0 24.5

2a 2b
TRANSVERSE OR FLOOR

Y
F
F F
LONGITUDINAL

SHELL OR BOTTOM PLATING

"Y" IS REGARDED AS A NON-LOAD CARRYING F
MEMBER

3) Welds of brackets and stiffeners to flanges

EDGE DISTANCE ≥ 10mm

4) Attachments on plate or face plate

EDGE DISTANCE ≥ 10mm

(Class G for edge distance < 10 mm)

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TABLE 1 (continued)
Fatigue Classification for Structural Details (1995)
Long-term
Distribution Permissible
Parameter Stress Range
Class
Designation Description γ kgf/mm2
F2 1) Fillet welds as shown below with rounded welds and no undercutting 0.7 39.3
0.8 31.1
0.9 25.5
1.0 21.6
1a 1b

Y Y

F F F F
2 2 2 2

"Y" is a non-load carrying member

2) Overlapped joints with soft-toe brackets as shown below

"Y"

F2 F2

3) Fillet welds with any undercutting at the corners dressed out by local grinding

3a 3b

F2

F2

F2 F2

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TABLE 1 (continued)
Fatigue Classification for Structural Details (1995)
Long-term
Distribution Permissible
Parameter Stress Range
Class
Designation Description γ kgf/mm2
G 1) Fillet welds in F2 − 1) without rounded toe welds or with limited minor 0.7 32.8
undercutting at corners or bracket toes 0.8 25.9
2) Overlapped joints as shown below 0.9 21.3
1.0 18.0

"Y"

G G

3) Fillet welds in F2 − 3) with minor undercutting

4) Doubler on face plate or flange

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TABLE 1 (continued)
Fatigue Classification for Structural Details (1995)
Long-term
Distribution Permissible
Parameter Stress Range
Class
Designation Description γ kgf/mm2
W Fillet welds-weld throat 0.7 28.3
0.8 22.3
0.9 18.4
1.0 15.5

Notes:
1 For brackets connecting two or more load carrying members, an appropriate stress concentration factor (SCF)
determined from fine mesh 3D or 2D finite element analysis is to be used. In this connection, the fatigue class at
bracket toes may be upgraded to class E as shown below.

E with SCF E with SCF

2 Additional information on stress concentration factors and the selection of compatible S-N data is given in
5C-1-A1/11.

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5 Permissible Stress Range

5.1 Assumptions (1995)

The fatigue strength of a structural detail under the loads specified here, in terms of a long-term, permissible
stress range, is to be evaluated using the criteria contained in this section. The key assumptions employed
are listed below for guidance.
• A linear cumulative damage model (i.e., Palmgren-Miner’s Rule) has been used in connection with the
S-N data in 5C-1-A1/Figure 1 (extracted from Ref. 1*).
• Cyclic stresses due to the loads in 5C-1-A1/7 have been used and the effects of mean stress have been
ignored.
• The target design life of the vessel is taken at 20 years.
• The long-term stress ranges on a detail can be characterized using a modified Weibull probability
distribution parameter (γ).
• Structural details are classified and described in 5C-1-A1/Table 1, “Fatigue Classification of Structural
Details”.
• Simple nominal stress (e.g., determined by P/A and M/SM) is the basis of fatigue assessment, rather
than more localized peak stress in way of weld.
* Ref 1: “Offshore Installations: Guidance on Design, Construction and Certification”, Department of Energy, U.K.,
Fourth Edition—1990, London: HMSO

The structural detail classification in 5C-1-A1/Table 1 is based on joint geometry and direction of the
dominant load. Where the loading or geometry is too complex for a simple classification, a finite element
analysis of the details is to be carried out to determine stress concentration factors. 5C-1-A1/13 contains
guidance on finite element analysis modeling to determine stress concentration factors for weld toe
locations that are typically found at longitudinal stiffener end connections.

5.3 Criteria (1995)

The permissible stress range obtained using the criteria in 5C-1-A1/5 is to be not less than the fatigue
inducing stress range obtained from 5C-1-A1/7.

5.5 Long Term Stress Distribution Parameter, γ (2002)

In 5C-1-A1/Table 1, the permissible stress range is given as a function of the long-term distribution
parameter, γ, as defined below.
γ = 1.40 − 0.2αL0.2 for 150 < L < 305 m
= 1.40 − 0.16αL 0.2
for 492 < L < 1000 ft
γ = 1.54 − 0.245α L 0.8 0.2
for L > 305 m
= 1.54 − 0.19α0.8L0.2 for L > 1000 ft
where
α = 1.0 for deck structures, including side shell and longitudinal bulkhead structures
within 0.1D from the deck
= 0.93 for bottom structures, including inner bottom and side shell, and longitudinal
bulkhead structures within 0.1D from the bottom
= 0.86 for side shell and longitudinal bulkhead structures within the region of 0.25D
upward and 0.3D downward from the mid-depth
= 0.80 for transverse bulkhead structures
α may be linearly interpolated for side shell and longitudinal bulkhead structures between 0.1D and 0.25D
(0.2D) from the deck (bottom).
L and D are the vessel’s length and depth, as defined in 3-1-1/3.1 and 3-1-1/7.

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5.7 Permissible Stress Range (1995)

5C-1-A1/Table 1 contains a listing of the permissible stress ranges, PS, for various categories of structural
details with 20-year minimum design fatigue life. The permissible stress range is determined for the
combination of the types of connections/details, the direction of dominant loading and the parameter, γ, as
defined in 5C-1-A1/5.5. Linear interpolation may be used to determine the values of permissible stress
range for a value of γ between those given.
(2003) For vessels designed for a fatigue life in excess of the minimum design fatigue life of 20 years (see
5C-1-1/1.2), the permissible stress ranges, PS, calculated above are to be modified by the following equation:
PS[Yr] = C(20/Yr)1/m PS
where
PS[Yr] = permissible stress ranges for the target design fatigue life of Yr
Yr = target value in years of “design fatigue life” set by the applicant in five (5) year
increments
m = 3 for Class D through W of S-N curve, 3.5 for Class C or 4 for Class B curves
C = correction factor related to target design fatigue life considering the two-segment S-N
curves (see 5C-1-A1/Table 1A).

TABLE 1A
Coefficient, C
Long-term Stress Target Design S-N Curve Classes
Distribution Parameter Fatigue Life, years B C D through W
γ Yr
0.7 20 1.000 1.000 1.000
30 1.004 1.006 1.011
40 1.007 1.012 1.020
50 1.010 1.016 1.028
0.8 20 1.000 1.000 1.000
30 1.005 1.008 1.014
40 1.009 1.015 1.025
50 1.013 1.021 1.035
0.9 20 1.000 1.000 1.000
30 1.006 1.010 1.016
40 1.012 1.019 1.030
50 1.017 1.026 1.042
1.0 20 1.000 1.000 1.000
30 1.008 1.012 1.019
40 1.015 1.022 1.035
50 1.020 1.031 1.049
Note: Linear interpolations may be used to determine the values of C where Yr = 25, 35
and 45

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FIGURE 1
Basic Design S-N Curves (1995)

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FIGURE 1 (continued)
Basic Design S-N Curves (1995)
Notes (For 5C-1-A1/Figure 1)
a) Basic design S-N curves
The basic design curves consist of linear relationships between log(SB) and log(N). They are based upon a
statistical analysis of appropriate experimental data and may be taken to represent two standard deviations
below the mean line.
Thus the basic S-N curves are of the form:
log(N) = log(K2) − m log(SB)
where
log(K2) = log(K1) − 2σ
N is the predicted number of cycles to failure under stress range SB;
K1 is a constant relating to the mean S-N curve;

σ is the standard deviation of log N;

m is the inverse slope of the S-N curve.
The relevant values of these terms are shown in the table below.
The S-N curves have a change of inverse slope from m to m + 2 at N = 107 cycles.
Details of basic S-N curves
K1 Standard deviation
Class K1 log10 loge m log10 loge K2
B 2.343 × 1015 15.3697 35.3900 4.0 0.1821 0.4194 1.01 × 1015
C 1.082 × 1014 14.0342 32.3153 3.5 0.2041 0.4700 4.23 × 1013
D 3.988 × 1012 12.6007 29.0144 3.0 0.2095 0.4824 1.52 × 1012
12
E 3.289 × 10 12.5169 28.8216 3.0 0.2509 0.5777 1.04 × 1012
F 1.726 × 1012 12.2370 28.1770 3.0 0.2183 0.5027 0.63 × 1012
F2 1.231 × 1012 12.0900 27.8387 3.0 0.2279 0.5248 0.43 × 1012
G 0.566 × 1012 11.7525 27.0614 3.0 0.1793 0.4129 0.25 × 1012
12
W 0.368 × 10 11.5662 26.6324 3.0 0.1846 0.4251 0.16 × 1012

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7 Fatigue Inducing Loads and Determination of Total Stress Ranges

7.1 General (1995)

This section provides: 1) the criteria to define the individual load components considered to cause fatigue
damage (see 5C-1-A1/7.3); 2) the load combination cases to be considered for different regions of the hull
containing the structural detail being evaluated (see 5C-1-A1/7.5); and 3) procedures to idealize the structural
components to obtain the total stress range acting on the structure.

7.3 Wave-induced Loads – Load Components (1995)

The fatigue-inducing load components to be considered are those induced by the seaway. They are divided
into the following three groups:
• Hull girder wave-induced bending moments (both vertical and horizontal), see 3-2-1/3.5 and 5C-1-3/5.1.
• External hydrodynamic pressures, and
• Internal tank loads (inertial liquid loads and added static head due to ship’s motion).

7.5 Fatigue Assessment Zones and Controlling Load Combination (1995)

Depending on the location of the structural details undergoing the fatigue assessment, different combinations
of load cases are to be used to find the appropriate stress range, as indicated below for indicated respective
zones.
7.5.1 Zone A
Zone A consists of deck and bottom structures, and side shell and longitudinal bulkhead structures
within 0.1D (D is vessel’s molded depth) from deck and bottom, respectively. For Zone A, stresses
are to be calculated based on the wave-induced loads specified in 5C-1-3/Table 1, as follows.
7.5.1(a) Calculate dynamic component of stresses for load cases LC1 through LC4, respectively.
7.5.1(b) Calculate two sets of stress ranges, one each for the following two pairs of combined
loading cases.
LC1 and LC2, and
LC3 and LC4
7.5.1(c) Use the greater of the stress ranges obtained by 5C-1-A1/7.5.1(b).
7.5.2 Zone B
Zone B consists of side shell and longitudinal bulkhead structures within the region between 0.25
upward and 0.30 downward from the mid-depth and all transverse bulkhead structures. The total
stress ranges for Zone B may be calculated based on the wave-induced loads specified in
5C-1-3/Table 1, as follows:
7.5.2(a) Calculate dynamic component of stresses for load cases LC5 through LC8, respectively.
7.5.2(b) Calculate two sets of stress ranges, one each for the following two pairs of combined
loading cases.
LC5 and LC6, and
LC7 and LC8
7.5.2(c) Use the greater of the stress ranges obtained by 5C-1-A1/7.5.2(b).

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7.5.3 Transitional Zone

Transitional zone between A and B consists of side shell and longitudinal bulkhead structures
between 0.1D and 0.25D (0.2D) from deck (bottom).
fR = fR(B) − [ fR(B) − fR(A)] yu /0.15D for upper transitional zone

fR = fR(B) − [ fR(B) − fR(A)] yl/0.1D for lower transitional zone

where
fR(A), fR(B) = the total stress range based on the combined load cases defined for Zone A or
Zone B, respectively
yu , y l = vertical distances from 0.25D (0.3D) upward (downward) from the mid-
depth to the location considered
7.5.4 Vessels with Either Special Loading Patterns or Special Structural Configuration
For vessels with either special loading patterns or special structural configurations/features, additional
load cases may be required for determining the stress range.

7.7 Primary Stress fd1 (1995)

fd1v and fd1h may be calculated by a simple beam approach. For assessing fatigue strength of side shell and
longitudinal bulkhead plating at welded connections, the value of wave-induced primary stress is to be
taken as that of maximum principal stress at the location considered to account for the combined load
effects of the direct stresses and shear stresses. For calculating the value of fd1v for longitudinal deck
members, normal camber may be disregarded.

7.9 Secondary Stress fd2

fd2 may be obtained from orthotropic plating or grillage methods with appropriate boundary conditions.
For those connections specified in 5C-1-A1/3.3.1, the wave-induced secondary bending stress fd2 may be
ignored.

7.11 Additional Secondary Stresses f d*2 and Tertiary Stresses fd3

7.11.1 Calculation of f d*2 (1 July 2005)

Where required, the additional secondary stresses acting at the flange of a longitudinal stiffener,
f d*2 , may be approximated by

f d*2 = CtCyM/SM N/cm2 (kgf/cm2, lbf/in2)

where
M = Cd psl2/12 N-cm (kgf-cm, lbf-in), at the supported ends of
longitudinal
Where flat bar stiffeners or brackets are fitted, the bending moment, M, given above, may be
adjusted to the location of the bracket’s toe, i.e., MX in 5C-1-4/Figure 6.
Where a longitudinal has remarkably different support stiffness at its two ends (e.g., a longitudinal
connected to a transverse bulkhead on one end), considerations should be given to the increase of
bending moment at the joint.
Cd = 1.15 for longitudinal stiffener connections at the transverse bulkhead for
all longitudinals
= 1.0 elsewhere
p = wave-induced local net pressure, in N/cm2 (kgf/cm2, lbf/in2), for the specified
location and load cases at the mid-span of the longitudinal considered
s = spacing of longitudinal stiffener, in cm (in.)

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l = unsupported span of longitudinal/stiffener, in cm (in.), as shown in

5C-1-4/Figure 5
SM = net section modulus of longitudinal with the associated effective plating, in
cm3 (in3), at flange or point considered. The effective breadth, be, in cm
(in.), may be determined as shown in 5C-1-4/Figure 6.
Cy = 0.656(d/z)4 for side shell longitudinals only
where z/d ≥ 0.9, but Cy ≥ 0.30
= 1.0 elsewhere
z = distance above keel of side shell longitudinal under consideration
d = scantling draft, m (ft)
Ct = correction factor for the combined bending and torsional stress induced by
lateral loads at the welded connection of the flat bar stiffener or bracket to
the flange of longitudinal, as shown in 5C-1-4/Figure 5.
= 1.0 + αr for unsymmetrical sections, fabricated or rolled
= 1.0 for tee and flat bars
αr = CnCp SM/K

Cp = 31.2dw(e/l)2
e = horizontal distance between web centerline and shear center of the cross
section, including longitudinal and the effective plating

≈ dw b 2f tf u/(2SM) cm (in.)

K = St. Venant torsion constant for the longitudinal’s cross section, excluding the
associated plating.

= [bf t 3f + dw t w3 ]/3 cm4 (in4)

Cn = coefficient given in 5C-1-A1/Figure 2, as a function of ψ, for point (1)

shown in 5C-1-A2/Figure 1.
u = 1 − 2b1/bf

ψ = 0.31l (K/Γ)1/2
Γ = warping constant

= mIyf d w2 + d w3 t w3 /36 cm6 (in6)

Iyf = tf b 3f (1.0 + 3.0u2Aw /As)/12 cm4 (in4)

Aw = dwtw cm2 (in2)

As = net sectional area of the longitudinals, excluding the associated plating, cm2 (in2)

m = 1.0 − u(0.7 − 0.1dw /bf)

dw, tw, b1, bf, tf, all in cm (in.), are as defined in 5C-1-A2/Figure 1.
For general applications, ar need not be taken greater than 0.65 for a fabricated angle bar and 0.50
for a rolled section.
For connection as specified in 5C-1-A1/3.3.2, the wave-induced additional secondary stress f d*2
may be ignored.

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FIGURE 2
Cn = Cn (ψ) (1995)

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7.11.2 Calculation of fd3

For welded joints of a stiffened plate panel, fd3 may be determined based on the wave-induced
local loads as specified in 5C-1-A1/7.11.1 above, using the approximate equations given below.
For direct calculation, non-linear effect and membrane stresses in the plate may be considered.
For plating subjected to lateral load, fd3 in the longitudinal direction is determined as:

fd3 = 0.182p(s/tn)2 N/cm2 (kgf/cm2, lbf/in2)

where
p = wave-induced local net pressure, in N/cm2 (kgf/cm2, lbf/in2)
s = spacing of longitudinal stiffeners, in cm (in.)
tn = net thickness of plate, in mm (in.)

9 Resulting Stress Ranges

9.1 Definitions (1995)

9.1.1
The total stress range, fR, is computed as the sum of the two stress ranges, as follows:
fR = cf (fRG + fRL) N/cm2 (kgf/cm2, lbf/in2)
where
fRG = global dynamic stress range, in N/cm2 (kgf/cm2, lbf/in2)
= |(fd1vi − fd1vj) + (fd1hi − fd1hj)|
fRL = local dynamic stress range, in N/cm2 (kgf/cm2, lbf/in2)

= cw|(fd2i + f d*2i + fd3i) − (fd2j + f d*2 j + fd3j)|

cf = adjustment factor to reflect a mean wasted condition

= 0.95
cw = coefficient for the weighted effects of the two paired loading patterns
= 0.75
fd1vi, fd1vj = wave-induced component of the primary stresses produced by hull girder
vertical bending, in N/cm2 (kgf/cm2, lbf/in2), for load case i and j of the
selected pairs of combined load cases, respectively
fd1hi, fd1h j = wave-induced component of the primary stresses produced by hull girder
horizontal bending, in N/cm2 (kgf/cm2, lbf/in2), for load case i and j of the
selected pairs of combined load cases, respectively
fd2i, fd2j = wave-induced component of the secondary bending stresses produced by the
bending of cross-stiffened panels between transverse bulkheads, in N/cm2
(kgf/cm2, lbf/in2), for load case i and j of the selected pairs of combined load
cases, respectively
f d*2i , f d*2 j = wave-induced component of the additional secondary stresses produced by
the local bending of the longitudinal stiffener between supporting structures
(e.g., transverse bulkheads and web frames), in N/cm2 (kgf/cm2, lbf/in2), for
load case i and j of the selected pairs of combined load cases, respectively
fd3i, fd3j = wave-induced component of the tertiary stresses produced by the local
bending of plate elements between the longitudinal stiffeners in, N/cm2
(kgf/cm2, lbf/in2), for load case i and j of the selected pairs of combined load
cases, respectively

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For calculating the wave-induced stresses, sign convention is to be observed for the respective
directions of wave-induced loads, as specified in 5C-1-3/Table 1. The wave-induced local loads
are to be calculated with the sign convention for the external and internal loads. However, the total
of the external and internal pressures, including both static and dynamic components, need not be
taken less than zero.
These wave-induced stresses are to be determined based on the net ship scantlings (see 5C-1-A1/1.3)
and in accordance with 5C-1-A1/7.5 through 5C-1-A1/7.11. The results of direct calculation, where
carried out, may also be considered.

11 Determination of Stress Concentration Factors (SCFs)

11.1 General (1995)

This section contains information on stress concentration factors (SCFs) to be considered in the fatigue
assessment.
Where, for a particular example shown, no specific value of SCF is given when one is called for, it indicates
that a finite element analysis is needed. When the fine mesh finite element approach is used, additional
information on calculations of stress concentration factors and the selection of compatible S-N data is
given in 5C-1-A1/13.

11.3 Sample Stress Concentration Factors (SCFs) (1 July 2001)

11.3.1 Cut-outs (Slots) for Longitudinals (1995)
SCFs, fatigue classifications and peak stress ranges may be determined in accordance with
5C-1-A1/Table 2 and 5C-1-A1/Figure 3.

TABLE 2
Ks (SCF) Values
Ks (SCF)
Configuration Unsymmetrical Flange Symmetrical Flange
Location [1] [2] [3] [1] [2] [3]
Single-sided Support 2.0 2.1 — 1.8 1.9 —
Single-sided Support with F.B. Stiffener 1.9 2.0 — 1.7 1.8 —
Double-sided Support 3.0 2.6 2.4 2.7 2.4 2.2
Double-sided Support with F.B. Stiffener 2.8 2.5 2.3 2.5 2.3 2.1

Notes: a The value of Ks is given, based on nominal shear stresses near the locations under consideration.
b Fatigue classification
Locations [1] and [2]: Class C or B as indicated in 5C-1-A1/Table 1
Location [3]: Class F
c The peak stress range is to be obtained from the following equations:
1 For locations [1] and [2] (1999)
fRi = cf [Ksifsi + fni]
where
cf = 0.95
fsi = fsc + αi fswi, fsi ≥ fsc
αi = 1.8 for single-sided support
= 1.0 for double-sided support
fni = normal stress range in the web plate
fswi = shear stress range in the web plate
= Fi/Aw
Fi is the calculated web shear force range at the location considered. Aw is the area of web.

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TABLE 2 (continued)
Ks (SCF) Values
fsc = shear stress range in the support (lug or collar plate)
= CyP/(Ac + As)
Cy is as defined in 5C-1-A1/7.11.1.
P = slpo
po = fluctuating lateral pressure
Ac = sectional area of the support or of both supports for double-sided support
As = sectional area of the flat bar stiffener, if any
Ksi = SCFs given above
s = spacing of longitudinal/stiffener
l = spacing of transverses

2 For location [3]

2
fR3 = cf [f n 3 + (Ks fs2)2]1/2
where
cf = 0.95
fn3 = normal stress range at location [3]
fs2 = shear stress range, as defined in 1 above, near location [3].
Ks = SCFs given above

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FIGURE 3
Cut-outs (Slots) For Longitudinal (1995)

Double - Sided Support

Web Plate
Class C or B F.B. Stiffener

[2] [2]
[1]
[1]
F1 F2 F1 F2
R R f3
f3
[1] [1]
[3] [3]
f s1 f s2 f s1 f s2

P R ≥ 35mm P

Web Plate
Class C or B F.B. Stiffener

[2] [2]
[1] [1]
F1 F2 F1 F2
R R R f3
f3
[1] [1] [3] [3]
f s1 f s2 f s2
f s1

R ≥ 35mm
P P

Single - Sided Support

Web Plate
Class C or B F.B. Stiffener

[2] [2] [1] [2]

F1 F2 F1 F2
R R R R
f3 f3
[1]
f s2 [3] f s1 f s1

R ≥ 35mm
P P

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11.3.2 Flat Bar Stiffener for Longitudinals (1999)

11.3.2(a) For assessing fatigue life of a flat bar stiffener at location [1] or [2] as shown in
5C-1-A1/Figure 4, the peak stress range is to be obtained from the following equation:

fRi = [(αi fs)2 + f L2i ]1/2 (i = 1 or 2)

where
fs = nominal stress range in the flat bar stiffener.
= cf Cy P/(As + Ac)
P, As, Ac, cf are as defined in 5C-1-A1/11.3.1 and Cy in 5C-1-A1/7.11.1. For flat bar stiffener with
soft-toed brackets, the brackets may be included in the calculation of As.
fLi = stress range in the longitudinal at Location i (i = 1 or 2), as specified in
5C-1-A1/9
αi = stress concentration factor at Location i (i = 1 or 2) accounting for
misalignment and local distortion
At location [1]
For flat bar stiffener without brackets
α1 = 1.50 for double-sided support connection
= 2.00 for single-sided support connection
For flat bar stiffener with brackets
α1 = 1.00 for double-sided support connection
= 1.25 for single-sided support connection
At location [2]
For flat bar stiffener without brackets
α2 = 1.25 for single or double-sided support connection
For flat bar stiffener with brackets
α2 = 1.00 for single or double-sided support connection
11.3.2(b) For assessing the fatigue life of the weld throat as shown in 5C-1-A1/Table 1, Class W,
the peak stress range fR at the weld may be obtained from the following equation:
fR = 1.25fs As/Asw
where
Asw = sectional area of the weld throat. Brackets may be included in the calculation
of Asw.
fs and As are as defined in 5C-1-A1/11.3.2(a) above.
11.3.2(c) For assessing fatigue life of the longitudinal, the fatigue classification given in
5C-1-A1/Table 1 for a longitudinal as the only load-carrying member is to be considered.
Alternatively, the fatigue classification shown in 5C-1-A1/Figure 4, in conjunction with the
combined stress effects, fR, may be used. In calculation of fR, the αi may be taken as 1.25 for both
locations [1] and [2].

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FIGURE 4
Fatigue Classification for Longitudinals in way of Flat Bar Stiffener

45° 45°

* *

* may be used in the calculation

of As and Asw.

Web Plate
Web Plate

Flat Bar

Flat Bar
[1]
Class E
fL1 [1] [2]

fs
[2] Class E Class E
fs

[1] Class F
Class F

fL1 fL2 fL1 fL2

Longitudinal Longitudinal
Shell Plating Shell Plating

P P

F.B. without Brackets F.B. with Brackets

11.3.3 Connection Between Transverse Bulkhead Vertical Web and Double Bottom Girder (1995)
Fatigue class designation and SCFs may be determined as shown in 5C-1-A1/Figure 5.

FIGURE 5
E with SCF

E with SCF

Full Penetration

E with SCF
E with SCF

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11.3.4 Connection Between Transverse Bulkhead Vertical Web and Deck Girder (1995)
Fatigue class designation and SCFs may be determined as shown in 5C-1-A1/Figure 6.

FIGURE 6

E with SCF E with SCF

E with SCF

E with SCF

11.3.5 End Connections of Transverse Bulkhead Horizontal Girder to Longitudinal of Side Shell or
Longitudinal Bulkhead (1995)
Fatigue class designation and SCFs may be determined as shown in 5C-1-A1/Figure 7.

FIGURE 7
Transv. Bhd

F or F 2
H. Girder

E with SCF
E with SCF

Side Shell or Longitudinal Bulkhead

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11.3.6 Connection of Transverse Bulkhead to Longitudinal Bulkhead (1995)

Fatigue class designation and SCFs may be determined as shown in 5C-1-A1/Figure 8.

FIGURE 8
Long. Bhd.
Side Shell

Transverse Bulkhead

F F
E with SCF

11.3.7 Doublers and Non-load Carrying Members on Deck or Shell Plating (1995)
Fatigue class designation may be determined as shown in 5C-1-A1/Figure 9.

FIGURE 9
Doublers and Non-load Carrying Members on Deck or Shell Plating

G
G
C E

D E F2

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13 Stress Concentration Factors Determined From Finite Element

Analysis

13.1 Introduction (1995)

S-N data and stress concentration factors (SCFs) are related to each other and therefore should be
considered together so that there is a consistent basis for the fatigue assessment.
The following guidance is intended to help make correct decisions.

13.3 S-N Data (1995)

S-N data are presented as a series of straight-lines plotted on log-log scale. The data reflect the results of
numerous tests, which often display considerable scatter. The recommended design curves for different
types of structural details and welded connections recognize the scatter in test results in that the design
curves have been based on the selection of the lower bound, 95% confidence limit. In other words, about
2.5% of the test failure results fall below this curve. Treating the design curve in this manner introduces a
high, yet reasonable degree of conservatism in the design and fatigue evaluation processes.
Individual S-N curves are presented to reflect certain generic structural geometry or arrangements.
5C-1-A1/Table 1 and 5C-1-A1/11.3 contain sketches of weld connections and other details typically found
in ship structures, giving a list of the S-N classification. This information is needed to assess the fatigue
strength of a detail. Also needed is a consistent way to establish the demands or load effects placed on the
detail, so that a compatible assessment can be made of the available strength versus the demand. Here is
where interpretation and judgment enter the fatigue assessment.
S-N curves are obtained from laboratory sample testing. The applied reference stress on the sample which
is used to establish the S-N data is referred to as the nominal stress. The nominal stress is established in a
simple manner, such as force divided by area and bending moment divided by section modulus (P/A &
M/SM). The structural properties used to establish the nominal stress are taken from locations away from
any discontinuities to exclude local stress concentration effects arising from the presence of a weld or other
local discontinuity. In an actual structure, it is rare that a match will be found with the tested sample
geometry and loading. One is then faced with the problem of making the appropriate interpretation.

13.5 S-N Data and SCFs (2003)

Selection of appropriate S-N data appears to be rather straightforward with respect to “standard details”
offered in 5C-1-A1/Table 1 or other similar reference. However, in the case of welded connections in
complex structures, it is required that SCFs be used to modify the nominal stress range. An often quoted
example of the need to modify nominal stress for fatigue assessment purposes is one shown in
5C-1-A1/Figure 10 below, relating to a hole drilled in the middle of a flat plate traversed by a butt weld.
In this example, the nominal stress SN is P/Area, but the stress to be used to assess the fatigue strength at
point A is SA or SN · SCF. This example is deceptively simple because it does not tell the entire story. The
most obvious deficiency of the example is that one needs to have a definitive and consistent basis to obtain
the SCF. There are reference books which indicate that based on the theory of elasticity, the SCF to be
applied in this case is 3.0. However, when the SCF is computed using the finite element analysis
techniques, the SCF obtained can be quite variable depending on the mesh size. The example does not
indicate which S-N curve should be applied, nor does the example say how it may be necessary to alter the
selection of the design S-N data in consideration of the aforementioned finite element analysis issues.
Therefore, if such interpretation questions exist for a simple example, the higher difficulty of appropriately
treating more complex structures should be evident.
Referring to the S-N curves to be applied to welded connections (for example, S-N curves D-W in
5C-1-A1/Figure 1), the SCFs resulting from the presence of the weld itself are already accounted for in
these curves. If one were to have the correct stress distribution in the region – from the weld to a location
sufficiently away from the weld toe (where the stress is suitably established by the nominal stress obtained
from P/A and M/SM) – the stress distribution may be generically separated into three distinct segments, as
shown in 5C-1-A1/Figure 11 below.

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• Region III is a segment where the stress gradient is controlled by the nominal stress gradient.
• Region II is a segment where the nominal stress gradient is being modified due to the presence of other
structure, such as the bracket end shown in the figure. This must be accounted for to obtain an
appropriate stress to be used in the fatigue analysis at the weld toe.
• Region I is a segment where the stress gradient is being modified due to the presence of the weld metal
itself. The stress concentration due to the weld is already accounted for in the S-N design curve and
will not be discussed further. Since the typical way to determine the stress distribution is via planar/linear
elements which ignore the weld, this is consistent with the method of analysis.
This general description of the stress distribution is again inconclusive because one does not know in
advance and with certainty the distances from the weld toe to where the indicated changes of slope for the
stress gradient occur. For this reason, definite rules need to be established to determine the slopes, and with
this knowledge, criteria established to be used to find the stress at the weld toe which should be used in the
fatigue assessment.
In this regard, two approaches can be used to find the stress at the weld toe, which reflect two methods of
structural idealization. One of these arises from the use of a conventional beam element idealization of the
structure including the end bracket connection, and the other arises from the use of a fine mesh finite
element idealization.
Using a beam element idealization, the nominal stress at any location (i.e., P/A and M/SM) can be obtained
(see 5C-1-4/Figure 6 for a sample beam element model).
In the beam element idealization, there will be questions as to whether or not the geometric stress
concentration due to the presence of other structure is adequately accounted for. This is the “Segment II”
stress gradient previously described. In the beam modeling approach shown in the figure, the influence on
stresses arising from the “carry over” of forces and bending moments from adjacent structural elements has
been accounted for (albeit approximately). At the same time, the strengthening effect of the brackets has
been conservatively ignored. Hence for engineering purposes, this approach is considered to be sufficient
in conjunction with the nominal stress obtained at the location of interest and the nominal S-N curve, i.e.,
the F or F2 Class S-N data, as appropriate.
In the fine mesh finite element analysis approach, one needs to define the element size to be used. This is
an area of uncertainty because the calculated stress distribution can be unduly affected by both the
employed mesh size and the uniformity of the mesh adjacent to the weld toe. Therefore, it is necessary to
establish “rules”, as given below, to be followed in the producing of the fine mesh model adjacent to the
weld toe. Furthermore, since the area adjacent to the weld toe (or other discontinuity of interest) may be
experiencing a large and rapid change of stress (i.e., a high stress gradient), it is also necessary to provide a
rule which can be used to establish the stress at the location where the fatigue assessment is to be made.
5C-1-A1/Figure 12 shows an acceptable method which can be used to extract and interpret the “near weld
toe” element stresses and to obtain a (linearly) extrapolated stress at the weld toe. When plate or shell
elements are used in the modeling, it is recommended that each element size is to be equal to the plate
thickness. When stresses are obtained in this manner, the use of the E Class S-N data is considered to be
acceptable.
Weld hot spot stress can be determined from linear extrapolation of surface component stresses at t/2 and
3t/2 from weld toe. The principal stresses at hot spot are then calculated based on the extrapolated stresses
and used for fatigue evaluation. Description of the numerical procedure is given in 5C-1-A1/13.7 below.

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FIGURE 10
(1995)
S N = P/Area

A
P
SA

SCF = SA / SN

FIGURE 11
(1995)
Calculated Stress

Physical Stress

I Bracket
II
III

Weld

Stiffener

FIGURE 12
(2003)
Peak Stress

Weld Toe "Hot Spot" Stress

t Weld Toe

~
~ t Weld Toe Location

t/2

3t/2

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13.7 Calculation of Hot Spot Stress for Fatigue Analysis of Ship Structures (2003)
The algorithm described in the following is applicable to obtain the hot spot stress for the point at the toe
of a weld. The weld typically connects either a flat bar member or a bracket to the flange of a longitudinal
stiffener, as shown in 5C-1-A1/Figure 13.
Consider the four points, P1 to P4, measured by the distances X1 to X4 from the weld toe, designated as the
origin of the coordinate system. These points are the centroids of four neighboring finite elements, the first
of which is adjacent to the weld toe. Assuming that the applicable surface component stresses, Si, at Pi
have been determined from FEM analysis, the corresponding stresses at “hot spot”, i.e., the stress at the
weld toe, can be determined by the following procedure:
13.7.1
Select two points, L and R, such that points L and R are situated at distances t/2 and 3t/2 from the
weld toe; i.e.,
XL = t/2, XR = 3t/2
where t denotes the thickness of the member to which elements 1 to 4 belong (e.g., the flange of a
longitudinal stiffener).
13.7.2
Let X = XL and compute the values of four coefficients, as follows:

C1 = [(X − X2)(X − X3)(X − X4)] / [(X1 − X2)(X1 − X3)(X1 − X4)]

C2 = [(X − X1)(X − X3)(X − X4)] / [(X2 − X1)(X2 − X3)(X2 − X4)]

C3 = [(X − X1)(X − X2)(X − X4)] / [(X3 − X1)(X3 − X2)(X3 − X4)]

C4 = [(X − X1)(X −X2)(X − X3)] / [(X4 − X1)(X4 − X2)(X4 − X3)]

The corresponding stress at Point L can be obtained by interpolation as:
SL = C1S1 + C2S2 + C3S3 + C4S4

13.7.3
Let X = XR and repeat the step in 5C-1-A1/13.7.2 to determine four new coefficients. The stress at
Point R can be interpolated likewise, i.e.,
SR = C1S1 + C2S2 + C3S3 + C4S4

13.7.4 (2003)
The corresponding stress at hot spot, S0, is given by

S0 = (3SL − SR)/2
Notes:
The algorithm presented in the foregoing involves two types of operations. The first is to utilize the stress values at the centroid
of the four elements considered to obtain estimates of stress at Points L and R by way of an interpolation algorithm known as
Lagrange interpolation. The second operation is to make use of the stress estimates, SL and SR, to obtain the hot spot stress
via linear extrapolation.
While the Lagrange interpolation is applicable to any order of polynomial, it is not advisable to go beyond the 3rd order
(cubic). Also, the even order polynomials are biased, so that leaves the choice between a linear scheme and a cubic scheme.
Therefore, the cubic interpolation, as described in 5C-1-A1/13.7.2, should be used. It can be observed that the coefficients,
C1 to C4 are all cubic polynomials. It is also evident that, when X = Xj, which is not equal to Xi, all of the C’s vanish except
Ci, and if X = Xi, Ci = 1.

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Appendix 1 Guide for Fatigue Strength Assessment of Tankers 5C-1-A1

FIGURE 13
(1995)
X
3t/2

t/2

(L) (R)

P1 P2 P3 P4
t

X1
X2
X3
X4

218 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
PART Appendix 2: Calculation of Critical Buckling Stresses

5C
CHAPTER 1 Vessels Intended to Carry Oil in Bulk (150 meters
(492 feet) or more in Length)

APPENDIX 2 Calculation of Critical Buckling Stresses

1 General
The critical buckling stresses for various structural elements and members may be determined in accordance
with this Appendix or other recognized design practices. Critical buckling stresses derived from experimental
data or analytical studies may be considered, provided that well-documented supporting data are submitted
for review.

3 Rectangular Plates (1995)

The critical buckling stresses for rectangular plate elements, such as plate panels between stiffeners; web
plates of longitudinals, girders, floors and transverses; flanges and face plates, may be obtained from the
following equations, with respect to uniaxial compression, bending and edge shear, respectively.
fci = fEi for fEi ≤ Pr fyi

fci = fyi[1 − Pr(1 − Pr)fyi/fEi] for fEi > Pr fyi

where
fci = critical buckling stress with respect to uniaxial compression, bending or edge shear,
separately, N/cm2 (kgf/cm2, lbf/in2)
fEi = Ki [π2E/12(1 − ν2)](tn/s)2, N/cm2 (kgf/cm2, lbf/in2)
Ki = buckling coefficient, as given in 5C-1-A2/Table 1
E = modulus of elasticity of the material, may be taken as 2.06 × 107 N/cm2
(2.1 × 106 kgf/cm2, 30 × 106 lbf/in2) for steel
ν = Poisson’s ratio, may be taken as 0.3 for steel
tn = net thickness of the plate, in cm (in.)
s = spacing of longitudinals/stiffeners, in cm (in.)
Pr = proportional linear elastic limit of the structure, may be taken as 0.6 for steel
fyi = fy, for uniaxial compression and bending

= fy / 3 , for edge shear

fy = specified minimum yield point of the material, in N/cm2 (kgf/cm2, lbf/in2)

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Appendix 2 Calculation of Critical Buckling Stresses 5C-1-A2

TABLE 1
Buckling Coefficient, Ki (1995)
For Critical Buckling Stress Corresponding to fL, fT, fb or fLT
I. Plate panel between stiffeners Ki
A Uniaxial compression l a. For f‘L, = fL: 4C1,
fL fL
1. Long plate b. For f‘L, = fL/3: 5.8C1,
l≥s S (see note)

f 'L f 'L

2. Wide plate fT a. For f‘T, = fT: [1 + (s/l)2]2C2

f 'T
l≥s b. For f‘T, = fT/3: 1.45[1 + (s/l)2]2C2
(see note)
S l

f 'T
fT

B Ideal Bending fb l fb
1. Long plate 24C1
s
l≥s
-fb -fb

2. Wide plate a. For 1.0 ≤ l/s ≤ 2.0 24 (s/l)2C2

fb
l≥s b. For 2.0 < l/s : 12 (s/l)C2
-fb

s l

-fb

fb

C Edge Shear fLT Ki

[5.34 + 4 (s/l)2]C1
s fLT

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Appendix 2 Calculation of Critical Buckling Stresses 5C-1-A2

TABLE 1 (continued)
Buckling Coefficient, Ki (1995)
D Values of C1 and C2
1. For plate panels between angles or tee stiffeners
C1 = 1.1
C2 = 1.3 within the double bottom or double side*
C2 = 1.2 elsewhere
2. For plate panels between flat bars or bulb plates
C1 = 1.0
C2 = 1.2 within the double bottom or double side*
C2 = 1.1 elsewhere
* applicable where shorter edges of a panel are supported by rigid structural members, such as bottom, inner
bottom, side shell, inner skin bulkhead, double bottom floor/girder and double side web stringer.

II. Web of Longitudinal or Stiffener Ki

A Axial compression
Same as I.A.1 by replacing s with depth of the web and l with unsupported span
a. For f‘L = fL : 4C
b. For f‘L = fL /2: 5.2C
(see note)
where
C = 1.0 for angle or tee stiffeners
C = 0.33 for bulb plates
C = 0.11 for flat bars
B Ideal Bending
Same as I.B.1 by replacing s with depth of the web and l with unsupported span 24C

III. Flange and Face Plate Ki

Axial Compression 0.44

b2 b2

s = b2
l = unsupported span
Note:
In I.A. (II.A), Ki for intermediate values of f‘L/fL (f‘T/fT) may be obtained by interpolation between a and b.

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Appendix 2 Calculation of Critical Buckling Stresses 5C-1-A2

5 Longitudinals and Stiffeners

5.1 Axial Compression (2002)

The critical buckling stress, fca, of a beam-column, i.e., the longitudinal and the associated effective plating,
with respect to axial compression may be obtained from the following equations:
fca = fE for fE ≤ Pr fy

fca = fy[1 − Pr(1 − Pr)fy /fE], for fE > Pr fy

where
fE = π2E/(l/r)2, N/cm2 (kgf/cm2, lbf/in2)

l = unsupported span of the longitudinal or stiffener, in cm (in.), as defined in

5C-1-4/Figure 5
r = radius of gyration of area Ae, in cm (in.)
Ae = As + bwL tn
As = net sectional area of the longitudinals or stiffeners, excluding the associated plating,
cm2 (in2)
bwL = effective width of the plating as given in 5C-1-5/5.3.2, in cm (in.)
tn = net thickness of the plating, in cm (in.)
fy = minimum specified yield point of the longitudinal or stiffener under consideration,
N/cm2 (kgf/cm2, lbf/in2)
Pr and E are as defined in 5C-1-A2/3.

5.3 Torsional/Flexural Buckling (2002)

The critical torsional/flexural buckling stress with respect to axial compression of a longitudinal, including
its associated plating (effective width, bwL), may be obtained from the following equations:

fct = fET for fET ≤ Pr fy

fct = fy[1 − Pr(1 − Pr)fy /fET] for fET > Pr fy

where
fct = critical torsional/flexural buckling stress with respect to axial compression, N/cm2
(kgf/cm2, lbf/in2)
fET = E[K/2.6 + (nπ/l)2Γ + Co(l/nπ)2/E]/Io[1 + Co(l/nπ)2/Io fcL], N/cm2 (kgf/cm2, lbf/in2)
K = St. Venant torsion constant for the longitudinal’s cross section, excluding the
associated plating.

= [bf t 3f + dw t w3 ]/3

Io = polar moment of inertia of the longitudinal, excluding the associated plating, about
the toe (intersection of web and plating), in cm4 (in4)

= Ix + mIy + As( xo2 + y o2 )

Ix, Iy = moment of inertia of the longitudinal about the x-and y-axis, respectively, through the
centroid of the longitudinal, excluding the plating (x-axis perpendicular to the web),
in cm4 (in4)
m = 1.0 − u(0.7 − 0.1dw /bf)

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Appendix 2 Calculation of Critical Buckling Stresses 5C-1-A2

u = unsymmetry factor
= 1 − 2b1/bf
xo = horizontal distance between centroid of stiffener, As, and centerline of the web plate,
cm (in.)
yo = vertical distance between the centroid of the longitudinal’s cross section and its toe,
cm (in.)
dw = depth of the web, cm (in.)
tw = net thickness of the web, cm (in.)
bf = total width of the flange/face plate, cm (in.)
b1 = smaller outstanding dimension of flange with respect to centerline of web (see
5C-1-A2/Figure 1), cm (in.)
tf = net thickness of the flange/face plate, cm (in.)

Co = Etn3/3s

Γ = warping constant

≅ mIyf d w2 + d w3 t w3 /36

Iyf = tf b 3f (1.0 + 3.0 u2dwtw /As)/12, cm4 (in4)

fcL = critical buckling stress for the associated plating, corresponding to n-half waves,
N/cm2 (kgf/cm2, lbf/in2)
= π2E(n/α + α/n)2(tn /s)2/12(1 − ν2)
α = l/s
n = number of half-wave which yield a smallest fET
fy = minimum specified yield point of the longitudinal or stiffener under consideration,
N/cm2 (kgf/cm2, lbf/in2)
Pr, E, s and ν are as defined in 5C-1-A2/3.

As, tn and l are as defined in 5C-1-A2/5.1.

5.5 Buckling Criteria for Unit Corrugation of Transverse Bulkhead (1996)

The critical buckling stress, which is also the ultimate bending stress, fcb, for a unit corrugation, may be
determined from the following equation (See 5C-1-5/5.11.2).
fcb = fEc for fEc ≤ Pr fy

fcb = [1 − Pr(1 − Pr)fy /fEc]fy for fEc > Pr fy

where
fEc = kcE(t/a)2

kc = 0.09[7.65 − 0.26 (c/a)2]2

c and a are widths of the web and flange panels, respectively, in cm2 (in2)
t = net thickness of the flange panel, in cm (in.)
Pr, fy and E are as defined in 5C-1-A2/3.

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Appendix 2 Calculation of Critical Buckling Stresses 5C-1-A2

FIGURE 1
Net Dimensions and Properties of Stiffeners (1995)
bf

b2 b1
1

tf

xo
CENTROID OF WEB
AND FACE PLATE
(NET SECTION)

tw

yo
dw

tp

be

1 = point considered for

coefficient, Cn, given
in 5C-1-A1/Figure 2

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Appendix 2 Calculation of Critical Buckling Stresses 5C-1-A2

7 Stiffened Panels (1995)

7.1 Large Stiffened Panels

For large stiffened panels between bulkheads or panels stiffened in one direction between transverses and
girders, the critical buckling stresses with respect to uniaxial compression may be determined from the
following equations:
fci = fEi for fEi ≤ Pr fy
fci = fy[1 − Pr(1 − Pr) fy /fEi] for fEi > Pr fy
where
fEi = kLπ 2(DLDT)1/2/tL b2 in the longitudinal direction, N/cm2 (kgf/cm2, lbf/in2)

fEi = kTπ 2(DLDT)1/2/tT l2 in the transverse direction, N/cm2 (kgf/cm2, lbf/in2)

kL = 4 for l/b ≥ 1

= [1/φ 2L + 2η + φ 2L ] for l/b < 1

kT = 4 for b/l ≥ 1

= [1/φ T2 + 2η + φ T2 ] for b/l < 1

DL = EIL /sL(1 − ν2)

DT = EIT /sT(1 − ν2)

DT = E t n3 /12(1 − ν2) if no stiffener in the transverse direction

l, b = length and width between transverse and longitudinal bulkheads, respectively, cm

(in.) (See 5C-1-A2/Figure 2)
tL, tT = net equivalent thickness of the plating and stiffener in the longitudinal and transverse
direction, respectively, cm (in.)
= (sLtn + AsL)/sL or (sTtn + AsT)/sT
sL, sT = spacing of longitudinals and transverses, respectively, cm (in.) (See 5C-1-A2/Figure 2)

φL = (l/b) (DT /DL)1/4

φT = (b/l) (DL /DT)1/4

η = [(IpLIpT)/(ILIT)]1/2
AsL, AsT = net sectional area of the longitudinal and transverse, excluding the associated plating,
respectively, cm2 (in2)
IpL, IpT = net moment of inertia of the effective plating alone (effective breadth due to shear
lag) about the neutral axis of the combined cross section, including stiffener and
plating, cm4 (in4)
IL, IT = net moment of inertia of the stiffener (one) with effective plating in the longitudinal
or transverse direction, respectively, cm4 (in4). If no stiffener, the moment of inertia is
calculated for the plating only.
Fy, Pr, E and ν are as defined in 5C-1-A2/3. tn is as defined in 5C-1-A2/5.1.

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Appendix 2 Calculation of Critical Buckling Stresses 5C-1-A2

With the exception of deck panels, when the lateral load parameter, qo, defined below, is greater than 5,
reduction of the critical buckling stresses given above is to be considered.
qo = pnb4/(π4tTDT)

qo = pnl4/(π4tLDL)
where
pn = average net lateral pressure, N/cm2 (kgf/cm2, lbf/in2)

DT, DL, b, l, tT, tL and sT are as defined above.

In this regard, the critical buckling stress may be approximated by:
f′ci = Ro fci N/cm2 (kgf/cm2, lbf/in2)
where
Ro = 1 − 0.045(qo − 5) for qo ≥ 5
For deck panels, Ro = 1.0 and f′ci = fci

FIGURE 2
l
T.B./S.S

sT

pn
longitudinal
b sL

L.B.

T.B. transverse plating, tn T.B.

7.3 Corrugated Transverse Bulkheads (1997)

For corrugated transverse bulkheads, the critical buckling stresses with respect to uniaxial compression
may be calculated from the equations given in 5C-1-A2/7.1 above by replacing the subscripts “L”and “T”
with “V” and “H” for the vertical and horizontal directions, respectively, and with the following modifications.
The rigidities DV are DH are defined as follows.
DV = EIv /s

DH = [s/(a + c)][Et3/12(1 − ν2)]

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Appendix 2 Calculation of Critical Buckling Stresses 5C-1-A2

where
Iv = moment of inertia of a unit corrugation with spacing s, s = a + ccos φ

= t/4[csin φ]2(a + c/4 + csin φ/12), in cm4 (in4)

a, c = widths of the flange and web panels, respectively, in cm (in.)
t = net thickness of the corrugations, in cm (in.)
E and ν are as defined in 5C-1-A2/3.
l = length of the corrugation, in cm (in.)
sv, sH = s

η, IpH, AsH = 0
AsV = tc sin φ

φ is as defined in 5C-1-4/Figure 9 or 5C-1-4/Figure 10.

9 Deep Girders, Webs and Stiffened Brackets

9.1 Critical Buckling Stresses of Web Plates and Large Brackets (1995)
The critical buckling stresses of web plates and large brackets between stiffeners may be obtained from the
equations given in 5C-1-A2/3 for uniaxial compression, bending and edge shear.

9.3 Effects of Cut-outs (1995)

The depth of cut-out, in general, is to be not greater than dw /3, and the stresses in the area calculated are to
account for the local increase due to the cut-out.
When cut-outs are present in the web plate, the effects of the cut-outs on reduction of the critical buckling
stresses are to be considered, as outlined in the subsections below.
9.3.1 Reinforced by Stiffeners Around Boundaries of Cut-outs
When reinforcement is made by installing straight stiffeners along boundaries of the cut-outs, the
critical buckling stresses of web plate between stiffeners with respect to compression and shear
may be obtained from equations given in 5C-1-A2/3.
9.3.2 Reinforced by Face Plates Around Contour of Cut-outs
When reinforcement is made by adding face plates along the contour of the cut-out, the critical
buckling stresses with respect to compression, bending and shear may be obtained from equations
given in 5C-1-A2/3, without reduction, provided that the net sectional area of the face plate is not
less than 8 t w2 , where tw is the net thickness of the web plate, and that depth of the cut-out is not
greater than dw /3, where dw is the depth of the web.
9.3.3 No Reinforcement Provided
When reinforcement is not provided, the buckling strength of the web plate surrounding the cut-
out may be treated as a strip of plate with one edge free and the other edge simply supported.

9.5 Tripping (1995)

To prevent tripping of deep girders and webs with wide flanges, tripping brackets are to be installed with a
spacing generally not greater than 3 meters (9.84 ft).
Design of tripping brackets may be based on the force P acting on the flange, as given by the following
equation:
1
P = 0.02fcl (Af + A )
3 w

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Appendix 2 Calculation of Critical Buckling Stresses 5C-1-A2

Af
P

1/3 Aw TRIPPING BRACKET

where
fcl = critical lateral buckling stress with respect to axial compression between tripping
brackets, N/cm2 (kgf/cm2, lbf/in2)
fcl = fce, for fce ≤ Pr fy

= fy[1 − Pr(1 − Pr)fy /fce], for fce > Pr fy

fce = 0.6E[(bf /tf)(tw /dw)3], N/cm2 (kgf/cm2, lbf/in2)
Af = net cross sectional area of the flange/face plate, in cm2 (in2)

Aw = net cross sectional area of the web, in cm2 (in2)

Bf, tf, dw, tw are as defined in 5C-1-A2/5.3.
E, Pr and fy are as defined in 5C-1-A2/3.

11 Stiffness and Proportions

To fully develop the intended buckling strength of the assemblies of structural members and panels,
supporting elements of plate panels and longitudinals are to satisfy the following requirements for stiffness
and proportion in highly stressed regions.

11.1 Stiffness of Longitudinals (1995)

The net moment of inertia of the longitudinals, io, with effective breadth of net plating, is to be not less
than that given by the following equation:

st n3
io = γo cm4 (in4)
12(1 − v 2 )
where
γo = (2.6 + 4.0δ)α2 + 12.4α − 13.2α1/2
δ = A/stn
α = l/s
s = spacing of longitudinals, cm (in.)
tn = net thickness of plating supported by the longitudinal, cm (in.)
ν = Poisson’s ratio
= 0.3 for steel
A = net sectional area of the longitudinal (excluding plating), cm2 (in2)
l = unsupported span of the longitudinal, cm (in.)

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m (492 ft) or more in Length)
Appendix 2 Calculation of Critical Buckling Stresses 5C-1-A2

11.3 Stiffness of Web Stiffeners (1995)

The net moment of inertia, i, of the web stiffener, with the effective breadth of net plating not exceeding s
or 0.33l, whichever is less, is not to be less than obtained from the following equations:
i = 0.17lt3(l/s)3 cm4 (in4), for l/s ≤ 2.0
3 2 4 4
i = 0.34lt (l/s) cm (in ), for l/s > 2.0
where
l = length of stiffener between effective supports, in cm (in.)
t = required net thickness of web plating, in cm (in.)
s = spacing of stiffeners, in cm (in.)

11.5 Stiffness of Supporting Members (1995)

The net moment of inertia of the supporting members, such as transverses and webs, is not to be less than
that obtained from the following equation:
Is/io ≥ 0.2(Bs/l)3(Bs/s)
where
Is = moment of inertia of the supporting member, including the effective plating, cm4 (in4)

io = moment of inertia of the longitudinals, including the effective plating, cm4 (in4)
Bs = unsupported span of the supporting member, cm (in.)

l and s are as defined in 5C-1-A2/11.1.

11.7 Proportions of Flanges and Face Plates (1995)

The breadth-thickness ratio of flanges and face plates of longitudinals and girders is to satisfy the limits
given below:
b2 /tf = 0.4(E/fy)1/2
where
b2 = larger outstanding dimension of flange, as given in 5C-1-A2/Figure 1, cm (in.)
tf = net thickness of flange/face plate, cm (in.)
E and fy are as defined in 5C-1-A2/3.

11.9 Proportions of Webs of Longitudinals and Stiffeners (1995)

The depth-thickness ratio of webs of longitudinals and stiffeners is to satisfy the limits given below.
dw /tw ≤ 1.5(E/fy)1/2 for angles and tee bars

dw /tw ≤ 0.85(E/fy)1/2 for bulb plates

dw /tw ≤ 0.5(E/fy)1/2 for flat bars

where dw and tw, are as defined in 5C-1-A2/5.3 and E and fy are as defined in 5C-1-A2/3.
When these limits are complied with, the assumption on buckling control stated in 5C-1-5/5.1.2(e) is
considered satisfied. If not, the buckling strength of the web is to be further investigated, as per 5C-1-A2/3.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 229
PART Appendix 3: Application to Single Hull Tankers

5C
CHAPTER 1 Vessels Intended to Carry Oil in Bulk (150 meters
(492 feet) or more in Length)

APPENDIX 3 Application to Single Hull Tankers

1 General
Where due to the nature of the cargo, single hull construction is permitted, the design criteria and evaluation
procedures specified in Section 5C-1-1 may also be applied to single hull tankers with modifications as
outlined in this Appendix.

1.1 Nominal Design Corrosion Values

Except as modified by the following, the nominal design corrosion values given in 5C-1-2/Table 1 are
applicable to the corresponding structural elements of single hull tankers based on the proposed usage of
the individual space.
For bottom plating and contiguously attached structures, the nominal design corrosion values to be used are:
Wing Ballast Tanks
Bottom Plating 1.00 mm
Bottom Longitudinals, Transverses and Girders (Web and Flange) 1.50 mm
Center or Wing Cargo Tanks
Bottom Plating 1.00 mm
Bottom Longitudinals, Transverses and Girders (Web and Flange) 1.00 mm

In designs which use the wing spaces for both ballast and cargo tanks, all longitudinal structural members
within these spaces are to have nominal design corrosion values as for ballast spaces. The nominal design
corrosion values for transverse structural members are to be based on the actual tank usage.
Consideration may be given for modifying the nominal design corrosion values, depending upon the
degree of cargo corrosiveness.

1.3 Load Criteria

The load criteria and load cases specified in 5C-1-3/1 through 5C-1-3/13 are generally applicable to single
hull tankers by considering the double bottom and wing ballast tanks, such as shown in 5C-1-3/Figure 1
and 5C-1-3/Figure 14, as null, except that the load patterns are specified in 5C-1-A3/Table 1 for bottom
and side shell structures.

1.5 Strength Criteria

1.5.1 Hull Girder Shear Strength
For single hull tankers with two or more longitudinal bulkheads, the net thickness of side shell and
longitudinal bulkhead plating is not to be less than that specified in 5C-1-4/5, wherein the shear
distribution factors, Ds and Di, and local load correction, Ri, may be derived either from direct
calculations or from Appendix 5C-2-A1.

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m or (492 ft) more in Length)
Appendix 3 Application to Single Hull Tankers 5C-1-A3

1.5.2 Plating and Longitudinals/Stiffeners

The strength requirements for plating and longitudinals/stiffeners specified in 5C-1-4/7 through
5C-1-4/17 and Section 5C-1-6 are directly applicable to single hull tankers by determining the
internal pressure in accordance with the actual tank arrangement.

3 Main Supporting Structures

3.1 Bottom Transverses

3.1.1 Section Modulus of Bottom Transverses
The net section modulus of the bottom transverse, in association with the effective bottom plating,
is not to be less than obtained from the following equation (see also 5C-1-4/1.3).
SM = M/fb cm3 (in3)

M = 10,000kcps l 2b N-cm (kgf-cm, lbf-in)

where
k = 1.0 (1.0, 0.269)
c = 0.83α2 for center tank
= 1.4 for wing tank
α = (lg /lb)[(Ib /Ig) (sg /s)]1/4 ≤ 1.0 for tankers with bottom girder
= 1.0 for tankers without bottom girder
lb = span of the bottom transverse, in m (ft), as indicated in 5C-1-A3/Figure 1;
the length is to be not less than 0.125B or one-half the breadth of the tank,
whichever is the greater
lg = span of the bottom girder, in m (ft), as indicated in 5C-1-A3/Figure 1
s = spacing of the bottom transverse, in m (ft)
sg = spacing of the bottom girder, in m (ft)
Ib and Ig = moments of inertia, in cm4 (in4), of the bottom transverse (Ib) and the bottom
girder (Ig) with effective plating to which they are attached (clear of bracket)
p = nominal pressure, in kN/m2 (tf/m2, Ltf/ft2), at the mid-span of the bottom
transverse, as specified in 5C-1-A3/Table 1
fb = permissible bending stress
= 0.70 Sm fy
Sm and fy are as defined in 5C-1-4/7.3.1.
B = vessel breadth, in m (ft)
3.1.2 Web Sectional Area of Bottom Transverse
The net sectional area of the web portion of the bottom transverse is not to be less than obtained
from the following equation:
A = F/fs cm2 (in2)
The shear force, F, in N (kgf, lbf), can be obtained from the following equation (see also 5C-1-4/1.3).
F = 1000k[ps(Kbls − he) + cDBcs] N (kgf, lbf)

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m or (492 ft) more in Length)
Appendix 3 Application to Single Hull Tankers 5C-1-A3

where
k = 1.0 (1.0, 2.24)
Kb = 0.5α for center tank
= 0.5 for wing tank
c = 0 for center tank
= 0.15 for wing tank without cross ties
= 0.06 for wing tank with one cross tie
= 0.03 for wing tank with two cross ties
ls = span of the bottom transverse, in m (ft), as indicated in 5C-1-A3/Figure 1
he = length of the bracket of bottom transverse, in m (ft), as indicated in
5C-1-A3/Figure 1
D = vessel depth, in m (ft)
Bc = breadth of the center tank, in m (ft)
P, s and α are as defined in 5C-1-A3/3.1.1.
fs = permissible shear stress
= 0.45 Sm fy
Sm and fy are as defined in 5C-1-4/7.3.1.

3.3 Bottom Girders

3.3.1 Section Modulus of Bottom Girders
The net section modulus of the bottom girder, in association with the effective bottom plating, is
not to be less than obtained from the following equation (see also 5C-1-4/1.3).
SM = M/fb cm3 (in3)
M = 10,000kcpsg l 2g N-cm (kgf-cm, lbf-in)
where
k = 1.0 (1.0, 0.269)
c = 1.0
p = nominal pressure, in kN/m2 (tf/m2, Ltf/ft2), at the mid-span of the bottom
girder, as specified in 5C-1-A3/Table 1
lg and sg are as defined in 5C-1-A3/3.1.1.
fb = 0.50 Sm fy
Sm and fy are as defined in 5C-1-4/7.3.1.
3.3.2 Web Sectional Area of Bottom Girder
The net sectional area of the web portion of the bottom girder is not to be less than obtained from
the following equation:
A = F/fs cm2 (in2)
The shear force, F, in N (kgf, lbf), can be obtained from the following equation (see 5C-1-4/1.3).
F = 1000kpsg (0.5ls − he)
where
k = 1.0 (1.0, 2.24)
ls = span of the bottom girder, in m (ft), as indicated in 5C-1-A3/Figure 1

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m or (492 ft) more in Length)
Appendix 3 Application to Single Hull Tankers 5C-1-A3

he = length of bracket of bottom girder, in m (ft), as indicted in 5C-1-A3/Figure 1

sg is as defined in 5C-1-A3/3.1.1.
p is as defined in 5C-1-A3/3.3.1.
fs = permissible shear stress
= 0.35 Sm fy
Sm and fy are as defined in 5C-1-4/7.3.1.

TABLE 1
Design Pressure for Local and Supporting Structures
A. Plating & Longitudinals/Stiffeners.
The nominal pressure, P = |Pi - Pe|, is to be determined from load cases “a” & “b” below, whichever is greater, with ku = 1.10 and kc = 1.0, unless
otherwise specified in the table
Case “a” At fwd end of the tank Case “b” At mid tank/fwd end of tank
Structural Members/ Draft/Wave Location and Coefficients Draft/Wave Location and Coefficients
Components Heading Angle Loading Pattern Pi Pe Heading Angle Loading Pattern Pi Pe
1. Bottom Plating & 2/3 design Full center and wing Ai Ae Design draft/0° Midtank of empty — Be
Long’l draft/0° tanks center and wing
tanks
2. Side Shell Plating & 2/3 design Starboard side of full Bi Ae Design draft/60° Midtank of empty — Be
Long’l draft/60° wing tank wing tank

B. Main Supporting Members

The nominal pressure, P = |Pi – Pe|, is to be determined at the midspan of the structural member at starboard side of vessel from load cases “a” and
“b” below, whichever is greater, with ku = 1.0, kc = 1.0, unless otherwise specified in the table
Midtank for Transverses Midtank for Transverses
Structural Members/ Draft/Wave Location and Coefficients Draft/Wave Location and Coefficients
Components Heading Angle Loading Pattern Pi Pe Heading Angle Loading Pattern Pi Pe
3. Bottom Transverse 2/3 design Full center and wing Ai Ae Design draft/0° Midtank of empty — Be
& Girder draft/0° tanks center and wing
tanks
4. Side Transverses 2/3 design Wing tanks full Bi — Design draft/60° Midtank of empty — Be
draft/60° wing tank

Notes:
1 (1 July 2005) For calculating pi and pe, the necessary coefficients are to be determined based on the following
designated groups:
a) For pi
Ai: wv = 0.75, wl(fwd bhd) = 0.25, wl(aft bhd) = –0.25, wt = 0.0, cφ = –0.35, ce = 0.0
Bi: wv = 0.4, wl(fwd bhd) = 0.2, wl(aft bhd) = –0.2, wt(starboard) = 0.4, wt(port) = –0.4, cφ = –0.3,
ce = 0.3
b) For pe
Ae: klo = 1.0, ku = 1.0, kc = –0.5
Be: klo = 1.0
2 For structures within 0.4L amidships, the nominal pressure is to be calculated for a tank located amidships. The
longest cargo and ballast tanks in the region should be considered as located amidships
3 In calculation of the nominal pressure, ρ g of the liquid cargoes is not to be taken less than 0.1025 kgf/cm2-m
(0.4444 lbf/in2-ft) for structural members 1 and 2 and is not to be taken less than 0.09 kgf/cm2-m (0.3902 lbf/in2-ft)
for cargo tanks and 0.1025 kgf/cm2-m (0.4444 lbf/in2-ft) for ballast tanks for structural members 3 and 4.
4 For all other structures, 5C-1-3/Table 3 is applicable.

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m or (492 ft) more in Length)
Appendix 3 Application to Single Hull Tankers 5C-1-A3

FIGURE 1
Spans of Transverses and Girders
CL

hU

lb ls
lb
hL

he he

ls
Bottom Transverse and Side Transverse
CL

lb
lb

he he he he

ls
ls
Bottom Transverse

lg

he he
ls
Bottom Girder

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m or (492 ft) more in Length)
Appendix 3 Application to Single Hull Tankers 5C-1-A3

3.5 Side Transverses

3.5.1 Section Modulus of Side Transverses
The net section modulus of the side transverse, in association with the effective side plating, is not
to be less than obtained from the following equation (see also 5C-1-4/1.3)
SM = M/fb cm3 (in3)

M = 10,000kcps l 2b N-cm (kgf-cm, lbf-in)

where
k = 1.0 (1.0, 0.269)
lb = span of side transverse, in m (ft), as indicated in 5C-1-A3/Figure 1
s = spacing of side transverse, in m (ft)
p = nominal pressure, in kN/m2 (tf/m2, Ltf/ft2), at the mid-span lb of the side
transverse, as specified in 5C-1-A3/Table 1
fb = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.70 Sm fy
c is given in 5C-1-A3/Table 2.
Sm and fy are as defined in 5C-1-4/7.3.1.
For tanker without cross ties, the section modulus of the side transverse, as required above, is to
extend at least up to 0.6lb from the lower end of the span. The value of the bending moment, M,
used for the calculation of the required section modulus of the remaining part of the side transverse
may be reduced, but not more than 20%.
In the case of one cross tie, the section modulus of the lower (upper) side transverse, as required
above, is to extend to the cross tie.
In the case of two cross ties, the section modulus of the lower (upper) side transverse, as required
above, is to extend to the lower (upper) cross tie and may be linearly interpolated between the
cross ties.

TABLE 2
Coefficient c for Side Transverse
Arrangement of Cross Ties For Upper Side Transverse For Lower Side Transverse
No Cross Tie 0.75
One Cross Tie in Wing Tank 0.19 0.33
Two Cross Ties in Wing Tank 0.13 0.20

3.5.2 Web Sectional Area of Side Transverses

The net sectional area of the web portion of the side transverse is not to be less than obtained from
the following equation:
A = F/fs cm2 (in2)
The shear force, F, in N (kgf, lbf), for the side transverse can be obtained from the following
equation (see also 5C-1-4/1.3):
F = 1000ks[KUls(PU + PL) − hUPU] for the upper part of the transverse
F = 1000ks[KLls(PU + PL) − hLPL] or
= 350ksKLls(PU + PL), whichever is greater, for the lower part of the transverse

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m or (492 ft) more in Length)
Appendix 3 Application to Single Hull Tankers 5C-1-A3

In no case is the shear force for the lower part of the transverse to be less than 120% of that for the
upper part of the transverse.
where
k = 1.0 (1.0, 2.24)
ls = span of the side transverse, in m (ft), as indicated in 5C-1-A3/Figure 1
s = spacing of the side transverse, in m (ft)
PU = nominal pressure, p, in kN/m2 (tf/m2, Ltf/ft2), at the mid-length of the upper
bracket (hU /2), as specified in 5C-1-A3/Table 1
PL = nominal pressure, p, in kN/m2 (tf/m2, Ltf/ft2), at the mid-length of the lower
bracket (hL /2), as specified in 5C-1-A3/Table 1
hU = length of the upper bracket, in m (ft), as indicated in 5C-1-A3/Figure 1
hL = length of the lower bracket, in m (ft), as indicated in 5C-1-A3/Figure 1
fs = permissible shear stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.45 Sm fy
KU and KL are given in 5C-1-A3/Table 3.
Sm and fy are as defined in 5C-1-4/7.3.1.
For a tanker without cross ties, the sectional area of the lower side transverse, as required above, is
to extend up to 0.15l from the toe of the lower bracket or 0.3ls from the lower end of the span,
whichever is greater.
In the case of one cross ties, the sectional area of the lower (upper) side transverse as required
above, is to extend to the cross tie.
In the case of two cross ties, the sectional area of the lower (upper) side transverse as required
above, is to extend to the lower (upper) cross tie and may be linearly interpolated between the
cross ties.

TABLE 3
Coefficients KU and KL for Side Transverses
Arrangement of Cross Ties KU KL
No Cross Tie 0.16 0.30
One Cross Tie in Wing Tank 0.09 0.21
Two Cross Ties in Wing Tank 0.075 0.16

3.7 Deck Transverses

3.7.1 Section Modulus of Deck Transverses
The net section modulus of deck transverses, in association with the effective deck plating, is not
to be less than obtained from the following equation (see also 5C-1-4/1.3).
SM = M/fb cm3 (in3)
For deck transverses in wing tanks:

M = k(10,000 c1ϕ ps l 2t + βsMs) ≥ Mo N-cm (kgf-cm, lbf-in)

For deck transverses in center tanks:

M = k(10,000 c1ϕ ps l 2t + βbMb) ≥ Mo N-cm (kgf-cm, lbf-in)

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m or (492 ft) more in Length)
Appendix 3 Application to Single Hull Tankers 5C-1-A3

where

Ms = 10,000c2 ps s l 2s

Mb = 10,000c2 pb s l 2b

Mo = 10,000kc3ϕ ps l 2t
k = 1.0 (1.0, 0.269)
p = nominal pressure, in kN/m2 (tf/m2, Ltf/ft2), at the mid-span of the deck
transverse under consideration, as specified in 5C-1-3/Table 3, Item 16
ps = corresponding nominal pressure, in kN/m2 (tf/m2, Ltf/ft2), at the mid-span of
the side transverse (5C-1-3/Table 3 , Item 16)
pb = corresponding nominal pressure, in kN/m2 (tf/m2, Ltf/ft2), at the mid-span of
the vertical web on longitudinal bulkhead (5C-1-3/Table 3 , Item 16)
c1 = 0.42 for tanks without deck girder
c1 = 0.42α2 for tanks with deck girders, min. 0.05 and max. 0.42
α = (lg /lt )[(sg /s) (IT /Ig)]1/4
lg = span of the deck girder, in m (ft), as indicated in 5C-1-4/Figure 2B-c
lt = span of the deck transverse, in m (ft), as indicated in 5C-1-4/Figure 2A, but
is not to be taken as less than 60% of the breadth of the tank
Ig, It = moments of inertia, in cm4 (in4), of the deck girder and deck transverse, clear
of the brackets, respectively
sg = spacing of the deck girders, in m (ft)
s = spacing of the deck transverses, in m (ft)
When calculating α, if more than one deck girder is fitted, the average values of sg, lg and Ig are to
be used when the girders are not identical.
ϕ = 1 − 5(ha /lt )α−1, to be not less than 0.6 for cargo tanks with deck girders
= 1 − 5(ha /lt ), to be not less than 0.6 for cargo tanks without deck girders
ha = distance, in m (ft), from the end of the span to the toe of the end bracket of
the deck transverse, as indicated in 5C-1-4/Figure 8
βs = 0.9[(ls/lt)(It /Is)], but is not to be taken less than 0.10 and need not be greater
than 0.65
βb = 0.9[(lb/lt)(It /Ib)], but is not to be taken less than 0.10 and need not be greater
than 0.50
ls and lb = spans, in m (ft), of side transverse and vertical web on longitudinal bulkhead,
respectively, as indicated in 5C-1-4/Figure 2A
Is and Ib = moments of inertia, in cm4 (in4), clear of the brackets, of side transverses and
vertical web on longitudinal bulkhead, respectively
fb = permissible bending stress, in N/cm2 (kgf/cm2, lbf/ in2)
= 0.70 Sm fy
Sm and fy are as defined in 5C-1-4/7.3.1.
c2 is given in 5C-1-A3/Table 4 below.
c3 = 0.83 for tanks without deck girders
= 1.1c1 for tanks with deck girders

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m or (492 ft) more in Length)
Appendix 3 Application to Single Hull Tankers 5C-1-A3

Where no cross ties or other effective supporting arrangements are provided for the wing tank
vertical webs, the deck transverses in the wing tanks are to have section modulus not less than
70% of that required for the upper side transverse.

TABLE 4
Coefficient c2 For Deck Transverse
Arrangement of Cross Ties Center Tank Wing Tank
No Cross Tie 0.4
One Cross Tie in Wing Tank 0.13 0.37
Two Cross Ties in Wing Tank 0.05 0.12

3.7.2 Web Sectional Area of Deck Transverse

The net sectional area of the web portion of deck transverses is not to be less than obtained from
the following equation:
A = F/fs cm2 (in2)
F = 1000k[c1 ps(0.50l − he) + c2 DBcs] N (kgf, lbf)
where
k = 1.0 (1.0, 2.24)
c1 = 1.30 for tanks without deck girder
= 0.90α1/2 for tanks with deck girder, min. 0.50 and max. 1.0
c2 = 0 for center tank
= 0.045 for wing tank
l = span of the deck transverse, in m (ft), as indicated in 5C-1-4/Figure 2A
he = length of the bracket, in m (ft), as indicated in 5C-1-4/Figure 2A-c and d and
5C-1-4/Figure 8
D = depth of the tanker, in m (ft), as defined in 3-1-1/7
Bc = breadth of the center tank, in m (ft)
P, s and α are as defined in 5C-1-A3/3.7.1.
fs = permissible shear stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.45 Sm fy
Sm and fy are as defined in 5C-1-4/7.3.1.
Area A is not to be less than the area obtained based on 5C-1-4/11.9 and 5C-1-4/11.11.

3.9 Longitudinal Bulkhead Vertical Webs

3.9.1 Section Modulus of Vertical Web on Longitudinal Bulkhead
The net section modulus of the vertical web, in association with the effective longitudinal bulkhead
plating, is to be not less than obtained from the following equation (see also 5C-1-4/1.3):
SM = M/fb cm3 (in3)

M = 10,000kcps l 2b N-cm (kgf-cm, lbf-in)

where
k = 1.0 (1.0, 0.269)
lb = span of vertical web, in m (ft), as indicated in 5C-1-4/Figure 2B-a

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m or (492 ft) more in Length)
Appendix 3 Application to Single Hull Tankers 5C-1-A3

s = spacing of vertical webs, in m (ft)

p = nominal pressure, in kN/m2 (tf/m2, Ltf/ft2) at mid-span lb of the vertical web,
as specified in 5C-1-3/Table 3
fb = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.70 Sm fy
c is given in 5C-1-A3/Table 5.
Sm and fy are as given in 5C-1-4/7.3.1.
For tanker without cross ties, the section modulus of the vertical web, as required above, is to
extend at least up to 0.6l from the lower end of the span. The value of the bending moment M,
used for the calculation of the required section modulus of the remaining part of vertical web, may
be reduced, but not more than 20%.
In the case of one cross tie, the section modulus of the lower (upper) vertical web, as required
above, is to extend to the cross tie.
In the case of two cross ties, the section modulus of lower (upper) vertical web, as required above,
is to extend to the lower (upper) cross tie and may be linearly interpolated between cross ties.

TABLE 5
Coefficient c for Vertical Web on Longitudinal Bulkhead
Arrangement of Cross Ties For Upper Vertical Web For Lower Vertical Web
No Cross Tie 0.75
One Cross Tie in Wing Tank 0.19 0.33
Two Cross Ties in Wing Tank 0.13 0.20

3.9.2 Web Sectional Area of Vertical Web on Longitudinal Bulkhead

The net sectional area of the web portion of the vertical web is not to be less than obtained from
the following equation:
A = F/fs cm2 (in2)
The shear force, F, in N (kgf, lbf), for the vertical web can be obtained from the following equation
(see also 5C-1-4/1.3):
F = 1000ks[KUl(PU + PL) − hUPU] for upper part of web

F = 1000ks[KLl(PU + PL) − hLPL] or

= 350ksKLl(PU + PL), whichever is greater, for lower part of web

In no case is the shear force for the lower part of the web to be less than 120% of that for the
upper part of the vertical web.
where
k = 1.0 (1.0, 2.24)
l = span of the vertical web, in m (ft), as indicated in 5C-1-4/Figure 2B-a
s = spacing of the vertical webs, in m (ft)
PU = nominal pressure, p, in kN/m2 (tf/m2, Ltf/ft2), at the mid-length of upper
bracket (hU /2), as specified in 5C-1-3/Table 3
PL = nominal pressure, p, in kN/m2 (tf/m2, Ltf/ft2), at the mid-length of the lower
bracket (hL /2), as specified in 5C-1-3/Table 3

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m or (492 ft) more in Length)
Appendix 3 Application to Single Hull Tankers 5C-1-A3

hU = length of the upper bracket, in m (ft), as indicated in 5C-1-4/Figure 2B-a

hL = length of the lower bracket, in m (ft), as indicated in 5C-1-4/Figure 2B-a
fs = permissible shear stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.45 Sm fy
KU and KL are given in 5C-1-A3/Table 6.
Sm and fy are as defined in 5C-1-4/7.3.1.
For tanker without cross ties, the sectional area of lower vertical webs, as required above, is to
extend up to 0.15l from the toe of the lower bracket or 0.3l from the lower end of the span,
whichever is greater.
In the case of one cross tie, the sectional area of the lower (upper) vertical web, as required above,
is to extend to the cross tie.
In the case of two cross ties, the sectional area of the lower (upper) vertical web, as required above, is
to extend to the lower (upper) cross tie and may be linearly interpolated between the cross ties.

TABLE 6
Coefficients KU and KL for Vertical Web on Longitudinal Bulkhead
Arrangement of Cross Ties KU KL
No Cross Tie 0.16 0.30
One Cross Tie in Wing Tank 0.09 0.21
Two Cross Ties in Wing Tank 0.075 0.16

3.11 Other Main Supporting Members

The strength and stiffness requirements specified in 5C-1-4/11 and 5C-1-4/15 for deck girders, vertical
webs and horizontal girders on transverse bulkheads and cross ties are applicable to single hull tankers.

3.13 Proportions
The following specifications are supplemental to 5C-1-4/11.11.
20% for bottom transverses without bottom girder
14% for bottom transverses with one girder
8% for bottom transverses with three girders
20% for bottom girders
12.5% for side transverses

5 Strength Assessment

5.1 General
The failure criteria and strength assessment procedures specified in Section 5C-1-5 are generally applicable
to single hull tankers, except for the special considerations outlined in 5C-1-A3/5.3 below.

5.3 Special Considerations

For assessing buckling and fatigue strength in accordance with 5C-1-5/5 and 5C-1-5/7, due consideration
is to be given to the buckling characteristics of large stiffened panels of the side shell and bottom
structures, as well as the realistic boundary conditions of side and bottom longitudinals at transverse
bulkheads for calculating the total stress range with respect to fatigue strength.

240 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
PART Appendix 4: Application to Mid-deck Tankers

5C
CHAPTER 1 Vessels Intended to Carry Oil in Bulk (150 meters
(492 feet) or more in Length)

APPENDIX 4 Application to Mid-deck Tankers (1995)

1 General

1.1 Design Concepts

The term “mid-deck tanker” refers to a cargo tank arrangement with wing ballast tanks, single bottom and
a tight deck (mid-deck) dividing the center or inboard cargo tanks into upper and lower tanks, as shown in
5C-1-A4/Figure 1. The location of the mid-deck is chosen to limit the maximum expected internal pressure
at the bottom to a level less than the minimum anticipated external pressures, in accordance with Regulation
13 F(4) of Annex I to the International Convention for the Prevention of Pollution from Ships, so that the
outflow of cargo oil may be prevented in grounding damage.

1.3 Design and Strength of Hull Structures

With regard to the design and strength of the hull structure, the criteria and evaluation procedures specified
in Section 5C-1-1 are generally applicable to mid-deck tankers. Modifications taking the unique characteristics
of this type of design into consideration are outlined in this Appendix.
The nominal design corrosion values specified in 5C-1-2/Table 1 and 5C-1-A3/1.1 may also be used for
mid-deck tankers. For the bottom and mid-deck structures in cargo tanks, the nominal design corrosion
values may be taken as 1.0 mm.

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m or (492 ft) more in Length)
Appendix 4 Application to Mid-deck Tankers 5C-1-A4

FIGURE 1
Typical Cross Section for Mid-deck Tankers

Upper Cargo Tank

Wing
Wing . B.T
.B.T .
.

Lower Cargo Tank

MDT1

Upper Cargo Upper Cargo

Tank (p) Tank (s)
Wing Wing
.B.T . B.T
.
.

Lower Cargo Lower Cargo

Tank (p) Tank (s)

MDT2

3 Load Criteria

3.1 Loading Patterns and Load Cases

In addition to the loading patterns shown in 5C-1-3/Figure 1a, loading patterns with respect to the upper
and lower cargo tanks are also to be considered to simulate the maximum internal loads imposed on the
mid-deck tanker structures. For this purpose, the cargo loading patterns given in 5C-1-A4/Figure 2 are to
be considered in conjunction with 5C-1-3/Table 1, unless the pattern is proven unnecessary.

242 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m or (492 ft) more in Length)
Appendix 4 Application to Mid-deck Tankers 5C-1-A4

FIGURE 2
Loading Pattern

a1. Load Cases No. 1 and 3 a2. Load Cases No. 1 and 3 b. Load Cases No. 2 and 4
2/3 Design Draft 2/3 Design Draft Design Draft

b2. Load Cases No.4 c. Load Cases No. 5 d. Load Cases No. 6
Design Draft 2/3 Design Draft 2/3 Design Draft

d2. Load Cases No.6* e. Load Cases No. 7* f. Load Cases No. 8
2/3 Design Draft 2/3 Design Draft Design Draft

LOWER TANK LOADED

* For tankers with an oil tight longitudinal bulkhead on the centerline
UPPER TANK LOADED where both cargo tanks, P&S, are anticipated to be loaded to the same
filling level at all times, the calculated internal pressures on the
LOWER AND UPPER longitudinal bulkhead may be reduced by multiplying a factor of 0.6
TANKS LOADED
WING TANK LOADED

3.3 Determination of Loads and Scantlings

3.3.1 Hull Girder Loads
The hull girder loads, external pressures, internal pressures and their nominal values and combined
effects, specified in 5C-1-3/3, 5C-1-3/5, 5C-1-3/7 and 5C-1-3/9, are applicable to mid-deck tankers,
except as outlined in 5C-1-A4/5.1 and 5C-1-A4/3.3.2 below.

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m or (492 ft) more in Length)
Appendix 4 Application to Mid-deck Tankers 5C-1-A4

3.3.2 Internal Pressure

In calculating the internal pressures in the lower cargo tanks, the tanks are to be assumed 100%
full to the level of mid-deck.
In addition, the scantlings of bulkheads between lower cargo tanks are to be satisfactory for a
scantling head to the upper deck with the vessel at the loading berth. Scantlings meeting the
requirements in Section 5C-2-1 and Section 5C-2-2 will be acceptable for this purpose.
3.3.3 Partially Filled Tanks
For partially filled tanks, the sloshing loads specified in 5C-1-3/11 are also to be considered.

5 Strength Criteria

5.1 Hull Girder and Structural Elements

In general, the strength criteria specified in Section 5C-1-4 are directly applicable to the mid-deck tankers,
with the exception of the items outlined in 5C-1-A4/5.1.1 and 5C-1-A4/5.1.2 below.
5.1.1 Hull Girder Shearing Strength
In determining the net thickness of the side shell and longitudinal bulkhead plating, the shear
distribution factors, Di, and local load corrections, Ri, given in 5C-1-4/5 are to be modified for the
proposed structural configurations and loading patterns. Direct calculation results justifying the
proposed modifications are to be submitted.
5.1.2 Bottom Structures
For the bottom shell plating and bottom longitudinals, the strength criteria specified in 5C-1-4/7
are directly applicable to the single bottom structures with the corresponding loading patterns
given in 5C-1-A4/3.1.
For the main supporting members, bottom transverses and bottom girders, the strength formulations
for the conventional single hull tankers given in Appendix 5C-1-A3 may be applied.

5.3 Mid-deck Structures

For scantling requirements for the mid-deck plating and mid-deck longitudinals, the equations given in 5C-
1-4/7.3 and 5C-1-4/7.5 may be employed, by taking the permissible bending stresses f1 = f2 = fb = 0.85 Sm
fy, as defined in 5C-1-4/7.3.2 and 5C-1-4/7.5. The nominal pressure, p, is to be taken from the loaded upper
tanks or lower tanks, whichever is greater.
For mid-deck transverses and mid-deck girders, the bending moments and shear forces may be determined
either by a direct calculation (3D F.E. analysis) or by the equations given in 5C-1-4/11 for critical load
cases and loading patterns specified in 5C-1-A4/3 above. In this case, the permissible bending and shear
stresses may be taken as fb = 0.7 Sm fy and fs = 0.45 Sm fy, as defined in 5C-1-4/11 for deck girders and deck
transverses, respectively.
The sectional properties of the mid-deck transverses are also to satisfy the requirements for cross ties,
given in 5C-1-4/15.

7 Strength Assessment

7.1 Failure Criteria

The failure criteria and strength assessment procedures specified in 5C-1-5/3 and 5C-1-5/9 are applicable
to mid-deck tankers with the modified loading patterns and load cases outlined in 5C-1-A4/3 above.

7.3 Special Considerations

In view of the unique cargo tank arrangement for mid-deck tankers, the shear lag effects with respect to the
effective hull girder section modulus and the transverse compression with respect to buckling/ultimate
strength of the mid-deck plating are to be properly considered for assessing strength of the structure.

244 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
PART Appendix 5: Guide for Hull Girder Ultimate Strength Assessment of Oil Carriers

5C
CHAPTER 1 Vessels Intended to Carry Oil in Bulk (150 meters
(492 feet) or more in Length)

APPENDIX 5 Guide for Hull Girder Ultimate Strength

Assessment of Oil Carriers (2010)

1 General
The hull structure may be verified for compliance with the hull girder ultimate strength requirements using
this Appendix. For vessels that are to be designed for compliance with the Common Structural Rules
(CSR), the specific hull girder ultimate strength requirements in Part 5A of the Steel Vessel Rules are to be
applied.
In general, the requirements are applicable to the hull structure within 0.4L amidships in sea-going
conditions. For vessels that are subject to higher bending moment, the hull girder ultimate strength in the
forebody and aft body regions is also to be verified.

3 Vertical Hull Girder Ultimate Limit State

The vertical hull girder ultimate bending capacity is to satisfy the following limit state equation:
MU
γSMsw + γWMw ≤
γR
where
Msw = still water bending moment, in kN-m (tf-m), in accordance with 3-2-1/3.3
Mw = maximum wave-induced bending moment, in kN-m (tf-m), in accordance with
3-2-1/3.5.1
MU = vertical hull girder ultimate bending capacity, in kN-m (tf-m), as defined in 5C-1-A5/5

γS = 1.0 partial safety factor for the still water bending moment
γw = 1.20 partial safety factor for the vertical wave bending moment covering
environmental and wave load prediction uncertainties
γR = 1.10 partial safety factor for the vertical hull girder bending capacity covering
material, geometric and strength prediction uncertainties
In general, for vessels where the hull girder ultimate strength is evaluated with gross scantlings, γR is to be
taken as 1.25.

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m or (492 ft) more in Length)
Appendix 5 Hull Girder Ultimate Strength Assessment of Oil Carriers 5C-1-A5

5 Hull Girder Ultimate Bending Moment Capacity

5.1 General
The ultimate bending moment capacities of a hull girder section, in hogging and sagging conditions, are
defined as the maximum values (positive MUH, negative MUS) on the static nonlinear bending moment-
curvature relationship M-κ. See 5C-1-A5/Figure 1. The curve represents the progressive collapse behavior
of the hull girder under vertical bending. Hull girder failure is controlled by buckling, ultimate strength and
yielding of longitudinal structural elements.

FIGURE 1
Bending Moment – Curvature Curve M-κ (2010)
M
Hogging Condition
MUH

MUS
Sagging Condition

The curvature of the critical inter-frame section,κ, is defined as:

θ -1
κ= m
l
where:
θ = relative angle rotation of the two neighboring cross-sections at transverse frame
positions
l = transverse frame spacing in m, i.e., span of longitudinals
The method for calculating the ultimate hull girder capacity is to identify the critical failure modes of all
main longitudinal structural elements.
Longitudinal structural members compressed beyond their buckling limit have reduced load carrying
capacity. All relevant failure modes for individual structural elements, such as plate buckling, torsional
stiffener buckling, stiffener web buckling, lateral or global stiffener buckling and their interactions, are to
be considered in order to identify the weakest inter-frame failure mode.
The effects of shear force, torsional loading, horizontal bending moment and lateral pressure are neglected.

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Appendix 5 Hull Girder Ultimate Strength Assessment of Oil Carriers 5C-1-A5

5.3 Physical Parameters

For the purpose of describing the calculation procedure in a concise manner, the physical parameters and
units used in the calculation procedure are given below.
5.3.1 Hull Girder Load and Cross Section Properties
Mi = hull girder bending moment, in kN-m (tf-m)
Fi = hull girder longitudinal force, in kN (tf)
Iv = hull girder moment of inertia, in m4

SM = hull girder section modulus, in m3

SMdk = elastic hull girder section modulus at deck at side, in m3

SMkl = elastic hull girder section modulus at bottom, in m3

κ = curvature of the ship cross section, in m-1

zj = distance from baseline, in m

5.3.2 Material Properties

σyd = specified minimum yield stress of the material, in N/cm2 (kgf/cm2)

E = Young’s modulus for steel, 2.06 × 107 N/cm2 (2.1 × 106 kgf/cm2)
ν = Poisson’s ratio, may be taken as 0.3 for steel
Φ = edge function as defined in 5C-1-A5/5.9.2
ε = relative strain defined in 5C-1-A5/5.9.2
5.3.3 Stiffener Sectional Properties
The properties of a longitudinal’s cross section are shown in 5C-1-A5/Figure 2.
As = sectional area of the longitudinal or stiffener, excluding the associated plating, in cm2
b1 = smaller outstanding dimension of flange with respect to centerline of web, in cm
bf = total width of the flange/face plate, in cm
dw = depth of the web, in cm
tp = net thickness of the plating, in cm
tf = net thickness of the flange/face plate, in cm
tw = net thickness of the web, in cm
xo = distance between centroid of the stiffener and centerline of the web plate, in cm
yo = distance between the centroid of the stiffener and the attached plate, in cm

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Appendix 5 Hull Girder Ultimate Strength Assessment of Oil Carriers 5C-1-A5

FIGURE 2
Dimensions and Properties of Stiffeners (2010)
bf

b2 b1

tf

xo
CENTROID OF WEB
AND FACE PLATE
(NET SECTION)

tw

yo
dw

tp

be

5.5 Calculation Procedure

The ultimate hull girder bending moment capacity MU is defined as the peak value of the curve with
vertical bending moment M versus the curvature κ of the ship cross section as shown in 5C-1-A5/Figure 1.
The curve M-κ is obtained by means of an incremental-iterative approach. The steps involved in the
procedure are given below.
The bending moment Mi which acts on the hull girder transverse section due to the imposed curvature κi is
calculated for each step of the incremental procedure. This imposed curvature corresponds to an angle of
rotation of the hull girder transverse section about its effective horizontal neutral axis, which induces an
axial strain ε in each hull structural element.
The stress σ induced in each structural element by the strain ε is obtained from the stress-strain curve σ-ε
of the element, which takes into account the behavior of the structural element in the nonlinear elasto-
plastic domain.
The force in each structural element is obtained from its area times the stress and these forces are summed
to derive the total axial force on the transverse section. Note the element area is taken as the total net area
of the structural element. This total force may not be zero as the effective neutral axis may have moved due
to the nonlinear response. Hence, it is necessary to adjust the neutral axis position, recalculate the element
strains, forces and total sectional force, and iterate until the total force is zero.
Once the position of the new neutral axis is known, then the correct stress distribution in the structural
elements is obtained. The bending moment Mi about the new neutral axis due to the imposed curvature κi is
then obtained by summing the moment contribution given by the force in each structural element.

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Appendix 5 Hull Girder Ultimate Strength Assessment of Oil Carriers 5C-1-A5

The main steps of the incremental-iterative approach are summarized as follows:

Step 1 Divide the hull girder transverse section into structural elements, (i.e., longitudinal stiffened panels
(one stiffener per element), hard corners and transversely stiffened panels), see 5C-1-A5/5.7.
Step 2 Derive the stress-strain curves (also known as the load-end shortening curves) for all structural
elements, see 5C-1-A5/5.9.
Step 3 Derive the expected maximum required curvature, κF. The curvature step size Δκ is to be taken as
κF/300. The curvature for the first step, κ1 is to be taken as Δκ.
Derive the neutral axis zNA-i for the first incremental step (i = 1) with the value of the elastic hull girder
section modulus, see 3-2-1/9.
Step 4 For each element (index j), calculate the strain εij = κi(zj – zNA-i) corresponding to κi, the corresponding
stress σj , and hence the force in the element σj Aj. The stress σj corresponding to the element strain εij is to
be taken as the minimum stress value from all applicable stress-strain curves σ-ε for that element.
Step 5 Determine the new neutral axis position zNA-i by checking the longitudinal force equilibrium over
the whole transverse section. Hence, adjust zNA-i until:
Fi = 10-3 ΔAjσj = 0
Note σj is positive for elements under compression and negative for elements under tension. Repeat from
Step 4 until equilibrium is satisfied. Equilibrium is satisfied when the change in neutral axis position is less
than 0.0001 m.
Step 6 Calculate the corresponding moment by summing the force contributions of all elements as follows:

Mi = 10-3 ∑σ j Aj (z j − z NA−i )
Step 7 Increase the curvature by Δκ, use the current neutral axis position as the initial value for the next
curvature increment and repeat from Step 4 until the maximum required curvature is reached. The ultimate
capacity is the peak value Mu from the M-κ curve. If the peak does not occur in the curve, then κF is to be
increased until the peak is reached.
The expected maximum required curvature κF is to be taken as:
(
max SM dk σ yd , SM kl σ yd )
κF = 3
EI v

5.7 Assumptions and Modeling of the Hull Girder Cross-section

In applying the procedure described in this Appendix, the following assumptions are to be made:
i) The ultimate strength is calculated at a hull girder transverse section between two adjacent transverse
webs.
ii) The hull girder transverse section remains plane during each curvature increment.
iii) The material properties of steel are assumed to be elastic, perfectly plastic.
iv) The hull girder transverse section can be divided into a set of elements which act independently of
each other.
v) The elements making up the hull girder transverse section are:
• Longitudinal stiffeners with attached plating, with structural behavior given in 5C-1-A5/5.9.2,
5C-1-A5/5.9.3, 5C-1-A5/5.9.4, 5C-1-A5/5.9.5 and 5C-1-A5/5.9.6
• Transversely stiffened plate panels, with structural behavior given in 5C-1-A5/5.9.7
• Hard corners, as defined below, with structural behavior given in 5C-1-A5/5.9.1

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Appendix 5 Hull Girder Ultimate Strength Assessment of Oil Carriers 5C-1-A5

vi) The following structural areas are to be defined as hard corners:

• The plating area adjacent to intersecting plates
• The plating area adjacent to knuckles in the plating with an angle greater than 30 degrees.
• Plating comprising rounded gunwales
An illustration of hard corner definition for girders on longitudinal bulkheads is given in
5C-1-A5/Figure 3.
vii) The size and modeling of hard corner elements is to be as follows:
• It is to be assumed that the hard corner extends up to s/2 from the plate intersection for
longitudinally stiffened plate, where s is the stiffener spacing
• It is to be assumed that the hard corner extends up to 20tgrs from the plate intersection for
transversely stiffened plates, where tgrs is the gross plate thickness.
Note: For transversely stiffened plate, the effective breadth of plate for the load shortening portion of the stress-strain
curve is to be taken as the full plate breadth, i.e., to the intersection of other plates – not from the end of the hard
corner. The area is to be calculated using the breadth between the intersecting plates.

FIGURE 3
Example of Defining Structural Elements (2010)
a) Example showing side shell, inner side and deck

Longitudinal
stiffener elements
Hard corner
elements

b) Example showing girder on longitudinal bulkhead

Longitudinal
stiffener elements

Hard corner
element

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m or (492 ft) more in Length)
Appendix 5 Hull Girder Ultimate Strength Assessment of Oil Carriers 5C-1-A5

5.9 Stress-strain Curves σ-ε (or Load-end Shortening Curves)

5.9.1 Hard Corners
Hard corners are sturdier elements which are assumed to buckle and fail in an elastic, perfectly
plastic manner. The relevant stress strain curve σ-ε is to be obtained for lengthened and shortened
hard corners according to 5C-1-A5/5.9.2.
5.9.2 Elasto-Plastic Failure of Structural Elements
The equation describing the stress-strain curve σ-ε of the elasto-plastic failure of structural
elements is to be obtained from the following formula, valid for both positive (compression or
shortening) of hard corners and negative (tension or lengthening) strains of all elements (see
5C-1-A5/Figure 4):
σ = Φ σyd kN/cm2 (kgf/cm2)
where
Φ = edge function
= –1 for ε < –1
= ε for –1 < ε < 1
= 1 for ε > 1
ε = relative strain
εE
=
ε yd

εE = element strain
εyd = strain corresponding to yield stress in the element
σ yd
=
E
Note: The signs of the stresses and strains in this Appendix are opposite to those in the rest of the Rules.

FIGURE 4
Example of Stress Strain Curves σ-ε (2010)
a) Stress strain curve σ-ε for elastic, perfectly plastic failure of a hard corner
σ

σyd

compression or
shortening

tension or
lengthening

−σyd

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FIGURE 4 (continued)
Example of Stress Strain Curves σ-ε (2010)
b) Typical stress strain curve σ-ε for elasto-plastic failure of a stiffener
σ

σyd

compression or
shortening
ε

tension or
lengthening

−σyd

5.9.3 Beam Column Buckling

The equation describing the shortening portion of the stress strain curve σCR1-ε for the beam
column buckling of stiffeners is to be obtained from the following formula:
⎛ As + beff − p t p ⎞
σ CR1 = Φσ C1 ⎜ ⎟ kN/cm2 (kgf/cm2)
⎜ As + st p ⎟
⎝ ⎠
where
σC1 = critical stress, in kgf/cm2 (kgf/cm2)

σ E1 σ yd
= for σE1 ≤ ε
ε 2
⎛ σ yd ε ⎞ σ yd
= σ yd ⎜⎜1 − ⎟ for σE1 > ε
⎝ 4σ E1 ⎟⎠ 2

σE1 = Euler column buckling stress, in kgf/cm2 (kgf/cm2)

IE
= π 2E
AE l 2

l = unsupported span of the longitudinal, in cm

s = plate breadth taken as the spacing between the stiffeners, in cm
IE = net moment of inertia of stiffeners, in cm4, with attached plating of width beff-s
beff-s = effective width, in cm, of the attached plating for the stiffener

s
= for βp > 1.0
βp

= s for βp ≤ 1.0

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Part 5C Specific Vessel Types
Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m or (492 ft) more in Length)
Appendix 5 Hull Girder Ultimate Strength Assessment of Oil Carriers 5C-1-A5

s εσ yd
βp =
tp E

AE = net area of stiffeners, in cm2, with attached plating of width beff-p

beff-p = effective width, in cm, of the plating

⎛ 2.25 1.25 ⎞
= ⎜ − 2 ⎟s for βp > 1.25
⎜ βp
⎝ β p ⎟⎠

= s for βp ≤ 1.25

5.9.4 Torsional Buckling of Stiffeners

The equation describing the shortening portion of the stress-strain curve σCR2-ε for the lateral-
flexural buckling of stiffeners is to be obtained according to the following formula:
⎛ As σ C 2 + st p σ CP ⎞
σ CR 2 = Φ⎜ ⎟ kN/cm2 (kgf/cm2)
⎜ As + st p ⎟
⎝ ⎠
where
σC2 = critical stress

σ E2 σ yd
= for σE2 ≤ ε
ε 2
⎛ σ yd ε ⎞ σ yd
= σ yd ⎜⎜1 − ⎟ for σE2 > ε
⎝ 4σ E 2 ⎟⎠ 2

σCP = ultimate strength of the attached plating for the stiffener

⎛ 2.25 1.25 ⎞
= ⎜ − 2 ⎟σ yd for βp > 1.25
⎜ βp β p ⎟⎠
⎝
= σyd for βp ≤ 1.25

βp = coefficient defined in 5C-1-A5/5.9.3

σE2 = Euler torsional buckling stress, in kN/cm2 (kgf/cm2), equal to reference stress
for torsional buckling σET
σET = E[K/2.6 + (nπ/l)2Γ + Co(l/nπ)2/E]/Io[1 + Co(l/nπ)2/Io fcL]
K = St. Venant torsion constant for the longitudinal’s cross section, excluding the
associated plating

= [b t f
3
f ]
+ d w t w3 / 3

Io = polar moment of inertia of the longitudinal, excluding the associated plating,

about the toe (intersection of web and plating)

= Ix + mIy + As x o2 + y o2 ( ) in cm4
Ix, Iy = moment of inertia of the longitudinal about the x- and y-axis, respectively,
through the centroid of the longitudinal, excluding the plating (x-axis
perpendicular to the web), in cm4
m = 1.0 − u(0.7 − 0.1dw/bf)

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m or (492 ft) more in Length)
Appendix 5 Hull Girder Ultimate Strength Assessment of Oil Carriers 5C-1-A5

u = unsymmetry factor
= 1 − 2b1/bf

Co = E t 3p /3s

Γ = warping constant

≅ mIyf d w2 + d w3 t w3 /36

Iyf = tf b 3f (1.0 + 3.0 u2dwtw/As)/12

fcL = critical buckling stress for the associated plating, corresponding to n-half
waves
= π2E(n/α + α/n)2(tp/s)2/12(1 − ν2)
α = l/s
l = unsupported span of the longitudinal, in cm
s = plate breadth taken as the spacing between the stiffeners, in cm
n = number of half-wave which yield a smallest σET

5.9.5 Web Local Buckling of Stiffeners with Flanged Profiles

The equation describing the shortening portion of the stress strain curve σCR3-ε for the web local
buckling of flanged stiffeners is to be obtained from the following formula:
⎛ beff − p t p + d w−eff t w + b f t f ⎞
σ CR 3 = Φσ yd ⎜ ⎟ kN/cm2 (kgf/cm2)
⎜ st p + d w t w + b f t f ⎟
⎝ ⎠
where
s = plate breadth taken as the spacing between the stiffeners, in cm
beff-p = effective width of the attached plating in cm, defined in 5C-1-A5/5.9.3
dw-eff = effective depth of the web, in cm

⎛ 2.25 1.25 ⎞
= ⎜ − 2 ⎟d w for βw > 1.25
⎜ β β w ⎟⎠
⎝ w

= dw for βw ≤ 1.25

dw εσ yd
βw =
tw E

5.9.6 Local Buckling of Flat Bar Stiffeners

The equation describing the shortening portion of the stress-strain curve σCR4-ε for the web local
buckling of flat bar stiffeners is to be obtained from the following formula:
⎛ As σ C 4 + st p σ CP ⎞
σ CR 4 = Φ⎜ ⎟ kN/cm2 (kgf/cm2)
⎜ As + st p ⎟
⎝ ⎠
where
σCP = ultimate strength of the attached plating, in kN/cm2 (kgf/cm2)

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Chapter 1 Vessels Intended to Carry Oil in Bulk (150 m or (492 ft) more in Length)
Appendix 5 Hull Girder Ultimate Strength Assessment of Oil Carriers 5C-1-A5

σC4 = critical stress, in kN/cm2 (kgf/cm2)

σ E4 σ yd
= for σE4 ≤ ε
ε 2
⎛ σ yd ε ⎞ σ yd
= σ yd ⎜⎜1 − ⎟ for σE4 > ε
⎝ 4σ E 4 ⎟⎠ 2

σE4 = Euler buckling stress

2
0.44π 2 E ⎛ t w ⎞
⎜ ⎟
=
( )
12 1 − ν 2 ⎜⎝ d w ⎟
⎠

5.9.7 Buckling of Transversely Stiffened Plate Panels

The equation describing the shortening portion of the stress-strain curve σCR5-ε for the buckling of
transversely stiffened panels is to be obtained from the following formula:
⎧ ⎡ ⎛ 2.25 1.25 ⎞ ⎞ ⎤
2
⎪σ ⎢ s ⎛ s ⎞⎛ 1
⎪ yd ⎜ ⎟
− 2 + 0.115⎜1 − ⎜
⎟ 1+ ⎟ ⎥
σ CR 5 = min ⎨ ⎢ l stf ⎜ βp βp ⎠⎟ ⎜ l ⎟⎜
stf ⎠⎝
2 ⎟ ⎥ kN/cm2 (kgf/cm2)
βp ⎠
⎢⎣ ⎝ ⎝ ⎥⎦
⎪
⎪⎩σ yd Φ

where
βp = coefficient defined in 5C-1-A5/5.9.3
s = plate breadth taken as the spacing between the stiffeners, in cm
lstf = span of stiffener equal to spacing between primary support members, in cm

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PART Chapter 2: Vessels Intended to Carry Oil in Bulk (Under 150 meters (492 feet) in Length)

5C
CHAPTER 2 Vessels Intended to Carry Oil in Bulk (Under 150
meters (492 feet) in Length)

CONTENTS
SECTION 1 Introduction ........................................................................................ 259
1 General ...........................................................................................259
1.1 Classification ...............................................................................259
1.3 Application ...................................................................................259
1.5 Detail Design of Internal Members...............................................260
1.7 Breaks .........................................................................................260
1.9 Variations.....................................................................................260
1.11 Loading Guidance........................................................................260
1.13 Higher-strength Materials ............................................................260
1.15 Pressure-vacuum Valve Setting ..................................................260
1.17 Protection of Structure .................................................................260
1.19 Aluminum Paint ...........................................................................260
1.21 Tank Design Pressures ...............................................................260
3 Special Requirements for Deep Loading ........................................261
3.1 Machinery Casings ......................................................................261
3.3 Access .........................................................................................261
3.5 Hatchways ...................................................................................261
3.7 Freeing Arrangements .................................................................261
3.9 Flooding.......................................................................................261
3.11 Ventilator .....................................................................................261
5 Arrangement ...................................................................................261
5.1 Subdivision ..................................................................................261
5.3 Cofferdams ..................................................................................262
5.5 Gastight Bulkheads......................................................................262
5.7 Cathodic Protection .....................................................................262
5.9 Ports in Pump Room Bulkheads ..................................................262
5.11 Location of Cargo Oil Tank Openings..........................................263
5.13 Structural Fire Protection .............................................................263
5.15 Allocation of Spaces ....................................................................263
5.17 Access to Upper Parts of Ballast Tanks on Double Hull
Tankers........................................................................................263
5.19 Access to All Spaces in the Cargo Area ......................................263
5.21 Duct Keels or Pipe Tunnels in Double Bottom.............................263
5.23 Ventilation....................................................................................264
5.25 Pumping Arrangements ...............................................................264
5.27 Electrical Equipment ....................................................................264
5.29 Testing.........................................................................................264
5.31 Machinery Spaces .......................................................................264

256 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
 SECTION 2 Hull Structure ..................................................................................... 265
1 Hull Girder Strength ........................................................................265
1.1 Normal-strength Standard ........................................................... 265
1.3 Still-water Bending Moment Calculations .................................... 265
3 Shell Plating ....................................................................................265
3.1 Amidships.................................................................................... 265
3.3 Sheer Strake ............................................................................... 267
3.5 Keel Plate .................................................................................... 267
3.7 Flat of Bottom Forward ................................................................ 267
3.9 Plating Outside Midship 0.4L....................................................... 267
3.11 Vessels under 76 m (250 ft) ........................................................ 267
3.13 Bilge Keels .................................................................................. 267
5 Deck Plating....................................................................................267
5.1 Amidships.................................................................................... 267
5.3 Vessels under 76 m (250 ft) ........................................................ 268
7 Bulkhead Plating .............................................................................268
7.1 Plating Thickness ........................................................................ 268
9 Long or Wide Tanks........................................................................268
9.1 Oiltight Bulkheads ....................................................................... 268
9.3 Nontight Bulkheads ..................................................................... 268
11 Double Bottom Structure.................................................................269
11.1 General........................................................................................ 269
11.3 Floors and Girders....................................................................... 269
11.5 Inner Bottom................................................................................ 269
11.7 Inner-bottom Longitudinals .......................................................... 269
11.9 Bottom Longitudinals ................................................................... 269
13 Deep Supporting Members .............................................................269
13.1 General........................................................................................ 269
13.3 Section Modulus.......................................................................... 269
13.5 Local Loading Conditions ............................................................ 271
13.7 Web Portion of Members............................................................. 271
13.9 Proportions .................................................................................. 272
13.11 Brackets ...................................................................................... 273
13.13 Stiffeners and Tripping Brackets ................................................. 273
13.15 Slots and Lightening Holes.......................................................... 273
13.17 Struts ........................................................................................... 274
15 Frames, Beams and Bulkhead Stiffeners .......................................274
15.1 Arrangement................................................................................ 274
15.3 Structural Sections ...................................................................... 275
15.5 Bilge Longitudinals ...................................................................... 276
15.7 Vessels under 76 m (250 ft) ........................................................ 276
17 Structure at Ends ............................................................................276

TABLE 1 Values of q for Ordinary Strength Steel ................................280

TABLE 2 Minimum Thickness for Web Portions of Members ..............280

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 257
 FIGURE 1 Coefficients and Lengths for Transverses ............................277
FIGURE 2 Lengths with Brackets ...........................................................278
FIGURE 3 Spans of Members and Effective Lengths or Heights of
Brackets ................................................................................279

SECTION 3 Cargo Oil and Associated Systems .................................................. 281

APPENDIX 1 Guide for Hull Girder Shear Strength for Tankers ........................... 282
1 Introduction .....................................................................................282
3 Allowable Still-water Shearing Force ..............................................282
3.1 Considering the Side Shell Plating...............................................282
3.3 Considering Various Longitudinal Bulkhead Plating ....................282
3.5 Reduction for Local Loads ...........................................................283
5 Distribution Factors .........................................................................284
5.1 For Vessels Having Two Longitudinal Bulkheads ........................284
5.3 For Vessels Having Three Longitudinal Bulkheads .....................284

FIGURE 1 Center Tank Region ..............................................................285

258 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
PART Section 1: Introduction

5C
CHAPTER 2 Vessels Intended to Carry Oil in Bulk (Under 150
meters (492 feet) in Length)

SECTION 1 Introduction

1 General

1.1 Classification
In accordance with 1-1-3/3, the classification notation À A1 Oil Carrier is to be assigned to vessels
designed for the carriage of oil cargoes in bulk and built to the requirements of this section and other
relevant sections of the Rules. As used in the Rules, the term “oil” refers to petroleum products having
flash points at or below 60°C (140°F), closed cup test, and specific gravity of not over 1.05. Vessels
intended to carry fuel oil having a flash point above 60°C (140°F), closed cup test, and to receive
classification À A1 Fuel Oil Carrier are to comply with the requirements of this section and other
relevant sections of the Rules, with the exception that the requirements for cofferdams, gas-tight bulkheads
and aluminum paint may be modified.

1.3 Application (1995)

1.3.1 Structural Arrangement
The requirements contained in this section are intended to apply to longitudinally framed, all-
welded tank vessels having proportions in accordance with 3-1-2/7, machinery aft and two or
more continuous longitudinal bulkheads. Where the arrangement differs from that described, the
scantlings may require adjustment to provide equivalent strength.
1.3.2 Vessels of Similar Type and Arrangement
The requirements are also intended to apply to other vessels of similar type and arrangement.
Double hull tanker: A tank vessel having full depth wing water ballast tanks or other non-cargo
spaces and full-breadth double bottom water ballast tanks or other non-cargo spaces within cargo
area to prevent liquid cargo outflow in stranding/collision. The size and capacity of these
wing/double bottom tanks or spaces are to comply with MARPOL 73/78 and national Regulations,
as applicable.
Mid-deck tanker: Refer to 5C-1-A4/1.1, Design Concepts.
Single hull tanker: A tank vessel which does not fit the above definitions of Double hull tanker
and Mid-deck tanker.
1.3.3 Engineering Analysis
It is recommended that compliance with the following requirements be accomplished through a
detailed investigation of the magnitude and distribution of the imposed longitudinal and transverse
forces by using an acceptable method of engineering analysis. The following paragraphs are to be
used as a guide in determining scantlings. Where it can be shown that the calculated stresses using
the loading conditions specified in 5C-2-2/13.5 are less than those stated to be permissible,
consideration will be given to scantlings alternative to those recommended by this section.

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Part 5C Specific Vessel Types
Chapter 2 Vessels Intended to Carry Oil in Bulk (Under 150 meters (492 feet) in Length)
Section 1 Introduction 5C-2-1

1.5 Detail Design of Internal Members

The detail design of internals is to follow the guidance given in 3-1-2/15.
See also Appendix 5C-1-A1 entitled, “Guide for the Fatigue Strength Assessment of Tankers.”

1.7 Breaks
Special care is to be taken throughout the structure to provide against local stresses at the ends of the oil
spaces, superstructures, etc. The main longitudinal bulkheads are to be suitably tapered at their ends, and
effective longitudinal bulkheads in the poop are to be located to provide effective continuity between the
structure in way of and beyond the main cargo spaces. Where the break of a superstructure lies within the
midship 0.5L, the required shell and deck scantlings for the midship 0.4L may be required to be extended
to effect a gradual taper of structure, and the deck stringer plate and sheer strake are to be increased. See
5C-2-2/3.3 and 5C-2-2/5.1. Where the breaks of the forecastle or poop are appreciably beyond the midship
0.5L, the requirements of 5C-2-2/3.3 and 5C-2-2/5.1 may be modified.

1.9 Variations
Tankers of special type or design differing from those described in the following Rules will be specially
considered on the basis of equivalent strength.

1.11 Loading Guidance

Loading guidance is to be as required by 3-2-1/7.

1.13 Higher-strength Materials

In general, applications of higher-strength materials for vessels intended to carry oil in bulk are to meet the
requirements of this section, but may be modified generally as outlined in the following sections:
Section 3-2-4 for longitudinals
Section 3-2-7 for longitudinals
Section 3-2-8 for deep longitudinal members (3-2-8/9.3)
Section 3-2-10 for bulkhead plating
Section 3-2-2 for shell plating
Section 3-2-3 for deck plating
In such cases, the allowable shearing stresses will be specially considered.

1.15 Pressure-vacuum Valve Setting (1993)

Where pressure-vacuum valves of cargo oil tanks are set at a pressure in excess of the pressure appropriate
to the length of the vessel (see 5C-1-7/11.11.2), the tank scantlings will be specially considered. Particular
attention is to be given to a higher pressure setting of pressure-vacuum valves as may be required for the
efficient operation of cargo vapor emission control systems, where installed.

1.17 Protection of Structure

For the protection of structure, see 3-2-18/5.

1.19 Aluminum Paint

Paint containing aluminum is not to be used in cargo tanks, on tank decks in way of cargo tanks, in pump
rooms and cofferdams, or in any other area where cargo vapor may accumulate, unless it has been shown
by appropriate tests that the paint to be used does not increase the fire hazard.

1.21 Tank Design Pressures (1993)

The requirements of this section are for tanks intended for the carriage of liquid cargoes with specific
gravities not greater than 1.05. Where the specific gravity is greater than 1.05, the design heads, h, are to
be increased by the ratio of specific gravity to 1.05. See also 5C-1-7/11 with regard to pressure-vacuum
valve setting and liquid level control.

260 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 2 Vessels Intended to Carry Oil in Bulk (Under 150 meters (492 feet) in Length)
Section 1 Introduction 5C-2-1

3 Special Requirements for Deep Loading (2003)

Where a vessel is intended to operate at the minimum freeboard allowed by the International Convention
on Load Lines, 1966, for Type-A vessels, the conditions in 5C-2-1/3.1 through 5C-2-1/3.9 are to be
complied with.

3.1 Machinery Casings

Machinery casings are normally to be protected by an enclosed poop or bridge, or by a deckhouse of
equivalent strength. The height of such structure is to be at least 1.8 m (5.9 ft) for vessels up to and
including 75 m (246 ft) in length, and 2.3 m (7.5 ft) for vessels 125 m (410 ft) or more in length. The
minimum height at intermediate lengths is to be obtained by interpolation. The bulkheads at the forward
ends of these structures are to be of not less scantlings than required for bridge-front bulkheads. (See
3-2-11/3) Machinery casings may be exposed, provided that they are specially stiffened and there are no
openings giving direct access from the freeboard deck to the machinery space. A door complying with the
requirements of 3-2-11/5.3 may, however, be permitted in the exposed machinery casing, provided that it
leads to a space or passageway which is as strongly constructed as the casing and is separated from the
engine room by a second door complying with 3-2-11/5.3. The sill of the exterior door is not to be less than
600 mm (23.5 in.), and of the second door not less than 230 mm (9 in.).

3.3 Access (1998)

Satisfactory arrangements are to be provided to safeguard the crew in reaching all parts used in the
necessary work of the vessel. See 3-2-17/3.

3.5 Hatchways
Exposed hatchways on the freeboard and forecastle decks or on the tops of expansion trunks are to be
provided with effective watertight covers of steel. The use of material other than steel will be subject to
special consideration.

3.7 Freeing Arrangements

Tankers with bulwarks are to have open rails fitted for at least half the length of the exposed parts of the
freeboard and superstructure deck or other effective freeing arrangements. The upper edge of the sheer
strake is to be kept as low as practicable. Where superstructures are connected by trunks, open rails are to
be fitted for the whole length of the exposed parts of the freeboard deck.

3.9 Flooding (2003)

Attention is called to the requirement of the International Convention on Load Lines, 1966, that tankers
over 150 m (492 ft) in freeboard length (see 3-1-1/3.3) to which freeboards less than those based solely on
Table B are assigned must be able to withstand the flooding of certain compartments.

3.11 Ventilators (2003)

Ventilators to spaces below the freeboard deck are to be specially stiffened or protected by superstructures
or other efficient means. See also 3-2-17/9.

5 Arrangement (1994)
The arrangements of the vessel are to comply with the requirements in Annex 1 to International Convention
for the Prevention of Pollution from Ships, with regard to segregated ballast tanks (Regulation 13), their
protective locations (Regulation 13E – where the option in Regulation 13F (4) or (5) is exercised), collision
or stranding considerations (Regulation 13F), hypothetical outflow of oil (Regulation 23), limitations of
size and arrangement of cargo tanks (Regulation 24) and slop tanks [Regulation 15 (2)(c)]. A valid
International Oil Pollution Certificate issued by the Administration maybe accepted as an evidence for
compliance with these requirements.

5.1 Subdivision
The length of the tanks, location of expansion trunks, and position of longitudinal bulkheads are to be
arranged to avoid excessive dynamic stresses in the hull structure.

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Part 5C Specific Vessel Types
Chapter 2 Vessels Intended to Carry Oil in Bulk (Under 150 meters (492 feet) in Length)
Section 1 Introduction 5C-2-1

5.3 Cofferdams
Cofferdams, thoroughly oiltight and vented, having widths as required for ready access, are to be provided
for the separation of all cargo tanks from galleys and living quarters, general cargo spaces which are below
the uppermost continuous deck, boiler rooms, and spaces containing propulsion machinery or other
machinery where sources of ignition are normally present. Pump rooms, compartments arranged solely for
ballast and fuel-oil tanks may be considered as cofferdams in compliance with this requirement.

5.5 Gastight Bulkheads

Gastight bulkheads are to be provided for the isolation of all cargo pumps and piping from spaces
containing stoves, boilers, propulsion machinery, electric apparatus or machinery where sources of ignition
are normally present. These bulkheads are to comply with the requirements of Section 3-2-9.

5.7 Cathodic Protection (1996)

5.7.1 Anode Installation Plan
Where sacrificial anodes are fitted in cargo or adjacent ballast tanks, their material, disposition and
details of their attachment are to be submitted for approval.
5.7.2 Magnesium and Magnesium Alloy Anodes
Magnesium and magnesium alloy anodes are not to be used.
5.7.3 Aluminum Anodes
Aluminum anodes may be used in cargo tanks of tankers, only in locations where the potential
energy does not exceed 275 N-m (28 kgf-m, 200 ft-lb). The height of the anode is to be measured
from the bottom of the tank to the center of the anode, and its weight is to be taken as the weight
of the anode as fitted, including the fitting devices and inserts.
Where aluminum anodes are located on horizontal surfaces, such as bulkhead girders and stringers,
not less than 1 m (39 in.) wide and fitted with an upstanding flange or face flat projecting not less
than 75 mm (3 in.) above the horizontal surface, the height of the anode may be measured from
this surface.
Aluminum anodes are not to be located under tank hatches or Butterworth openings unless
protected from falling metal objects by adjacent tank structure.
5.7.4 Anode Attachment
Anodes are to have steel cores sufficiently rigid to avoid resonance in the anode support and are to
be designed to retain the anode even when it is wasted.
The steel cores are to be attached to the structure by means of continuous welds at least 75 mm (3
in.) in length. Alternatively, they may be attached to separate supports by bolting. A minimum of
two bolts with locknuts are to be used.
The supports at each end of an anode are not to be attached to items of structure which are likely
to move independently.
Anode inserts and supports welded directly to the structure are to be arranged so that the welds are
clear of stress raisers.

5.9 Ports in Pump Room Bulkheads

Where fixed ports are fitted in the bulkheads between a pump room and the machinery or other safe space,
they are to maintain the gastight and watertight integrity of the bulkhead. The ports are to be effectively
protected against the possibility of mechanical damage and are to be fire resistant. Hinged port covers of
steel, having non-corrosive hinge pins and secured from the safe space side, are to be provided. The covers
are to provide strength and integrity equivalent to the unpierced bulkhead. Except where it may interfere
with the function of the port, the covers are to be secured in the closed position. The use of material other
than steel for the covers will be subject to special consideration. Lighting fixtures providing strength and
integrity equivalent to that of the port covers will be accepted as an alternative.

262 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 2 Vessels Intended to Carry Oil in Bulk (Under 150 meters (492 feet) in Length)
Section 1 Introduction 5C-2-1

5.11 Location of Cargo Oil Tank Openings

Cargo oil tank openings, including those for tank cleaning, which are not intended to be secured gastight at
all times during the normal operation of the vessel are not to be located in enclosed spaces. For the purpose
of this requirement, spaces open on one side only are to be considered enclosed. See also 5C-2-1/5.21.

5.13 Structural Fire Protection

The applicable requirements of Section 3-4-1 are to be complied with.

5.15 Allocation of Spaces (1994)

5.15.1 Tanks Forward of the Collision Bulkhead
Tanks forward of the collision bulkhead are not to be arranged for the carriage of oil or other
liquid substances that are flammable.
5.15.2 Double Bottom Spaces and Wing Tank Spaces
For vessels of 5000 tons deadweight and above, double bottom spaces or wing tanks adjacent to
cargo oil tanks are to be allocated for water ballast or spaces other than cargo and fuel oil tanks.

5.17 Access to Upper Parts of Ballast Tanks on Double Hull Tankers (1993)
Where the structural configuration within the ballast tank is such that it will prevent access to upper parts
of tanks for required close-up examination (see 7-3-2/5.13.4) by conventional means, such as a raft on
partly filled tank, permanent means of safe access is to be provided. The details of access are to be
submitted for review.
Where horizontal girders or diaphragm plates are fitted, they may be considered as a part of permanent
access. Alternative arrangements to the above may be considered upon submission.

5.19 Access to All Spaces in the Cargo Area (1 October 1994)

Access to cofferdams, ballast tanks, cargo tanks and other spaces in the cargo area is to be direct and from
the open deck. Access to double bottom spaces may be through a cargo pump room, deep cofferdam, pipe
tunnel or similar space, provided ventilation is suitable.
For access through horizontal openings, hatches or manholes, the access is to be of a size such as to allow a
person wearing a self-contained, air-breathing apparatus and protective equipment (see 4-7-3/15.5) to
ascend or descend any ladder without obstruction and also to provide a clear opening to facilitate the
hoisting of an injured person from the bottom of the space. In general, the minimum clear opening is not to
be less than 600 mm (24 in.) by 600 mm (24 in.).
For access through vertical openings or manholes providing passage through the length and breadth of the
space, the minimum clear opening is not to be less than 600 mm (24 in.) by 800 mm (32 in.) at a height of
not more than 600 mm (24 in.) from the bottom shell plating, unless gratings or other footholds are
provided.
For vessels less than 5000 tons deadweight, smaller dimensions than above may be approved, provided
that the ability to remove an injured person can be demonstrated to the satisfaction of the Surveyor.

5.21 Duct Keels or Pipe Tunnels in Double Bottom (2000)

Duct keels or pipe tunnels are not to pass into machinery spaces. Provision is to be made for at least two
exits to the open deck, arranged at a maximum distance from each other. One of these exits may lead to
the cargo pump room, provided that it is watertight and fitted with a watertight door complying with the
requirements of 3-2-9/9.1 and in addition with the following:
i) In addition to bridge operation, the watertight door is to be capable of being closed from outside
the main pump room entrance; and
ii) A notice is to be affixed at each operating position to the effect that the watertight door is to be
kept closed during normal operations of the vessel, except when access to the pipe tunnel is required.
For the requirements of ventilation and gas detection in duct keels or pipe tunnels, see 5C-1-7/31.17.1.

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5.23 Ventilation (1996)

Holes are to be cut in every part of the structure where, otherwise, there might be a chance of gases being
“pocketed”. Special attention is to be paid to the effective ventilation of pump rooms and other working
spaces adjacent to the oil tanks. In general, floor plating is to be of an open type not to restrict the flow of
air. See 5C-1-7/17.1 and 5C-1-7/17.5. Efficient means are to be provided for clearing the oil spaces of
dangerous vapors by means of artificial ventilation or steam. For the venting of the cargo tanks, see
5C-1-7/11 and 5C-1-7/21.

5.25 Pumping Arrangements

See applicable requirements in Section 5C-1-7.

5.27 Electrical Equipment (2004)

See 5C-1-7/31 and 5C-1-7/33.

5.29 Testing
Requirements for testing are contained in Part 3, Chapter 7.

5.31 Machinery Spaces

Machinery spaces aft are to be specially stiffened transversely. Longitudinal material at the break is also to
be specially considered to reduce concentrated stresses in this region. Longitudinal wing bulkheads are to
be incorporated with the machinery casings or with substantial accommodation bulkheads in the tween
decks and within the poop.

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5C
CHAPTER 2 Vessels Intended to Carry Oil in Bulk (Under 150
meters (492 feet) in Length)

SECTION 2 Hull Structure

1 Hull Girder Strength

1.1 Normal-strength Standard

The longitudinal hull girder strength is to be not less than required by the equations given in 3-2-1/3.7 and
3-2-1/3.9.

1.3 Still-water Bending Moment Calculations

For still-water bending moment calculations, see 3-2-1/3.3.

3 Shell Plating

3.1 Amidships
Shell plating within the midship 0.4L is to be of not less thickness than is required for longitudinal hull
girder strength, or than that obtained from 5C-2-2/3.1.1 through 5C-2-2/3.1.3.
3.1.1 Bottom Shell Thickness
The thickness t of the bottom shell plating is not to be less than obtained from 5C-2-2/3.1.1(a) and
5C-2-2/3.1.1(b).
3.1.1(a)
t = S(L + 8.54)/(42L + 2318) mm
t = S(L + 28)/(42L + 7602) in.
where
S = frame spacing, in mm (in.), but is not to be taken as less than 88% of that
given in 3-2-5/1.7 or 864 mm (34 in.), whichever is less
L = length of vessel, as defined in 3-1-1/3.1, in m (ft)
Where the bottom hull girder section modulus SMA is greater than required by 3-2-1/3.7.1, and
still-water bending moment calculations are submitted, the thickness of bottom shell may be
obtained from the above equation multiplied by the factor, Rb. Special consideration will be given
to vessels constructed of higher-strength steel.

SM R
Rb = is not to be taken less than 0.85
SM A

where
SMR = hull girder section modulus required by 3-2-1/3.7.1, in cm2-m (in2-ft)
SMA = bottom hull girder section modulus of vessel, in cm2-m (in2-ft), with the
greater of the bottom shell plating thickness obtained when applying Rn or Rb

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3.1.1(b)

t = 0.006s 0.7 d + 0.02( L − 50) + 2.5 mm

t = 0.00331s 0.7d + 0.02( L − 164) + 0.1 in.

Where the bottom hull girder section modulus, SMA, is greater than required by 3-2-1/3.7.1, and
still-water bending moment calculations are submitted, the thickness of bottom shell may be
obtained from the above equation multiplied by the factor, Rn. Special consideration will be given
to vessels constructed of higher-strength steel.

1
Rn = is not to be taken less than 0.85
fp ⎛ SM R ⎞
⎜⎜1 − ⎟ +1
σ t ⎝ SM A ⎟⎠

where
fp = nominal permissible bending stress, in kN/cm2 (tf/cm2, Ltf/in2), as given in
3-2-1/3.7.1
σt = KPt(s/t)2, in kN/cm2 (tf/cm2, Ltf/in2)
K = 0.34 for longitudinal framing
Pt = (0.638H + d)a kN/cm2 (tf/cm2, Ltf/in2)

a = 1.005 × 10-3 (1.025 × 10-4, 1.984 × 10-4)

t = bottom shell plating thickness required by the equation in 5C-2-2/3.1.1(b)
above, in mm (in.)
H = wave parameter defined in 3-2-2/3.13.2
SMR and SMA are as defined in 5C-2-2/3.1.1(a) and L, s and d are as defined in 5C-2-2/3.1.2(b).
SMR /SMA is not to be taken as less than 0.70.

3.1.2 Side Shell Thickness

The thickness t of the side shell plating is not to be less than obtained from 5C-2-2/3.1.2(a) and
5C-2-2/3.1.2(b).
3.1.2(a)
t = 0.01L(6.5 + 21/D) mm
t = 0.0003937L(2.0 + 21/D) in.
3.1.2(b)

t = 0.0052s 0.7 d + 0.02 L + 2.5 mm

t = 0.00287s 0.7 d + 0.02 L + 0.1 in.

where
L = length of vessel, as defined in 3-1-1/3.1
d = molded draft to the summer load line, as defined 3-1-1/9, in m (ft)
D = molded depth, as defined in 3-1-1/7.1, in m (ft)
s = spacing of bottom longitudinals or spacing of side longitudinals or vertical
side frames, in mm (in.)

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3.1.3 Shell Thickness

Where a double bottom is fitted and is not to be used for the carriage of cargo oil, the bottom shell
thickness may be in accordance with 3-2-2/3.13, and if a double skin is provided and is not to be
used for the carriage of cargo oil, the side shell thickness may be in accordance with 3-2-2/3.9.

3.3 Sheer Strake

The thickness of the sheer strake is to be not less than the thickness of the side-shell plating, nor less than
required by 5C-2-2/5.1.2. The thickness is to be increased 25% in way of breaks of superstructures, but this
increase need not exceed 6.5 mm (0.25 in.). See 5C-2-1/1.7.

3.5 Keel Plate

The thickness of the flat plate keel is to be not less than that required for the bottom shell plating at that
location increased by 1.5 mm (0.06 in.), except where the submitted docking plan (see 3-1-2/11) specifies
all docking blocks be arranged away from the keel.

3.7 Flat of Bottom Forward (2002)

Where the heavy ballast draft forward is less than 0.04L, the plating on the flat of bottom forward of the
location in 3-2-4/Table 1 is to be not less than required in 3-2-2/5.5. For this assessment, the heavy ballast
draft forward is to be determined by using segregated ballast tanks only.

3.9 Plating Outside Midship 0.4L

The bottom and side shell, including the sheer strake beyond the midship 0.4L, is generally to be in
accordance with the requirements of 3-2-2/5 and is to be gradually reduced from the midship thickness to
the end thickness.

3.11 Vessels under 76 m (250 ft)

In vessels under 76 m (250 ft) in length, the thickness of the bottom shell is to be obtained from 3-2-2/3 of
the ABS Rules for Building and Classing Steel Vessels Under 90 meters (295 feet) in Length.

3.13 Bilge Keels

Bilge keels are to comply with 3-2-2/13.

5 Deck Plating

5.1 Amidships
The strength deck within the midship 0.4L is to be of not less thickness than is required to provide the deck
area necessary for longitudinal strength in accordance with 5C-2-2/1; nor is the thickness to be less than
determined by the following equations for thickness of deck plating.
5.1.1
L
t = 0.0016s L − 53 + 0.32 − 2.5 mm
D
L
t = 0.000883s L − 174 + 0.0126 − 0.1 in.
D
5.1.2
s (30.48 + L)
t= L < 150 m
4981 + 40 L
s (100 + L )
t= L < 492 ft.
16339 + 40 L

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Section 2 Hull Structure 5C-2-2

where
t = plate thickness, in mm (in.)
s = spacing of deck longitudinals, in mm (in.)
L = length of vessel, as defined in 3-1-1/3.1, in m (ft)
D = molded depth, as defined in 3-1-1/7.1, in m (ft)
The thickness of the stringer plate is to be increased 25% in way of breaks of superstructures, but
this increase need not exceed 6.5 mm (0.25 in.). See 5C-2-1/1.7. The required deck area is to be
maintained throughout the midship 0.4L of the vessel or beyond the end of a superstructure at or
near the midship 0.4L point. From these locations to the ends of the vessel, the deck area may be
gradually reduced in accordance with 3-2-1/11.3. Where bending moment envelope curves are
used to determine the required hull girder section modulus, the foregoing requirements for strength
deck area may be modified in accordance with 3-2-1/11.3. Where so modified, the strength deck
area is to be maintained a suitable distance from superstructure breaks and is to be extended into
the superstructure to provide adequate structural continuity.

5.3 Vessels under 76 m (250 ft)

In vessels under 76 m (250 ft) in length, the thickness of deck plating is to be obtained from 3-2-3/3 of the
ABS Rules for Building and Classing Steel Vessels Under 90 meters (295 feet) in Length.

7 Bulkhead Plating

7.1 Plating Thickness

The plating is to be of not less thickness than is required for deep-tank bulkheads by 3-2-10/3, where h is
measured from the lower edge of the plate to the top of the hatch or to a point located 1.22 m (4 ft) above
the deck at side amidships, whichever is greater. The upper strakes are to be increased above these
requirements to provide a proper margin for corrosion. It is recommended that the top strake of a complete
longitudinal bulkhead be not less than 9.5 mm (3/8 in.) in vessels of 91.5 m (300 ft) length, and 12.5 mm
(1/2 in.) in vessels of 150 m (492 ft) length, and that the strake below the top strake be not less than 9.5 mm
(3/8 in.) in vessels of 122 m (400 ft) length and 10.5 mm (13/32 in.) in vessels of 150 m (492 ft) in length,
with intermediate thicknesses for intermediate lengths. See also 5C-2-1/1.15.

9 Long or Wide Tanks

9.1 Oiltight Bulkheads

In vessels fitted with long tanks, the scantlings of oiltight transverse bulkheads in smooth-sided tanks are
to be specially considered when the spacing between tight bulkheads, nontight bulkheads or partial
bulkhead exceeds 12 m (40 ft) in the case of corrugated-type construction, or 15 m (50 ft) in the case of
flat-plate type of construction. Special consideration is to be given to the scantlings of longitudinal oiltight
bulkheads forming the boundaries of wide tanks. Where the length of the smooth-sided tanks exceeds 0.1L
or the breadth exceeds 0.6B, nontight bulkheads are to be fitted, unless calculations are submitted to prove
that no resonance due to sloshing will occur in service.
Alternatively, reinforcements to the bulkheads and decks, without nontight bulkheads, may be determined
by an acceptable method of engineering analysis.

9.3 Nontight Bulkheads

Nontight bulkheads are to be fitted in line with transverse webs, bulkheads or other structures with
equivalent rigidity. They are to be suitably stiffened. Openings in the nontight bulkhead are to have
generous radii and their aggregate area is not to exceed 33%, nor be less than 10% of the area of the
nontight bulkhead. Plating is to be of not less thickness than that required by 5C-2-2/Table 2. Section
moduli of stiffeners and webs may be one half of the requirements for watertight bulkheads in 3-2-9/5.3
and 3-2-9/5.7. Alternatively, the opening ratio and scantlings may be determined by an acceptable method
of engineering analysis.

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Section 2 Hull Structure 5C-2-2

11 Double Bottom Structure

11.1 General
Where a double bottom is fitted, it is generally to be arranged with a centerline girder, or equivalent, and,
where necessary, with full depth side girders similar to Section 3-2-4. The arrangements and scantlings of
the double bottom structure as given in Section 3-2-4 may be used, except where modified by this section.
Increases in scantlings may be required where tanks other than double bottom tanks are designed to be
empty with the vessel in a loaded condition. Alternatively, consideration will be given to arrangements and
scantlings determined by an acceptable method of engineering analysis, provided that the stresses are in
compliance with 5C-2-2/13. Where ducts forming a part of the double bottom structure are used as a part
of the piping system for transferring cargo oil or ballast, the structural integrity of the duct is to be
safeguarded by suitable relief valves or other arrangement to limit the pressure in the system to the value
for which it is designed.

11.3 Floors and Girders

In general, the thickness of floors and girders is to be as required by Section 3-2-4. Where tanks adjacent to
the double bottom are designed to be empty with the vessel in a loaded condition, the floors and girders in
the double bottom are to be specially considered. Where the heavy ballast draft forward is less than 0.04L
the fore-end arrangement of floors and side girders is to comply with 3-2-4/13.1 and 3-2-4/13.3.

11.5 Inner Bottom

The thickness of the inner-bottom plating is to be not less than required by Section 3-2-10, with a head to
1.22 m (4 ft) above the deck at side amidships or to the top of the hatch, whichever is greater.

11.7 Inner-bottom Longitudinals

Scantlings for inner-bottom longitudinals are to be not less than required in 5C-2-2/15.3, using c = 1.00.
Where effective struts are fitted between inner-bottom and bottom longitudinals, the inner-bottom
longitudinals are not to be less than required in 5C-2-2/15.3, using c = 0.55, or 85% of the requirement in
3-2-4/11.3 for bottom longitudinals, using c = 0.715, whichever is greater.

11.9 Bottom Longitudinals

Scantlings for bottom longitudinals are to be not less than required by 3-2-4/11.3. Where effective struts
are fitted between bottom and inner-bottom longitudinals, the bottom longitudinals are to be not less than
90% of the inner-bottom longitudinal requirement in 5C-2-2/15.3, using c = 0.55, or the requirement in
3-2-4/11.3, using c = 0.715, whichever is greater. Where the heavy ballast draft forward is less than 0.04L,
the flat of bottom-forward longitudinals are to be not less than required by 3-2-4/13.5.

13 Deep Supporting Members

13.1 General
Webs, girders and transverses which support longitudinal frames, beams or bulkhead stiffeners, generally
are to be in accordance with the following paragraphs. It is recommended that deep girders be arranged in
line with webs and stringers to provide complete planes of stiffness. In vessels without a longitudinal
centerline bulkhead or effective centerline supporting member, a center vertical keel having sufficient
strength to serve as one line of support is to be provided where centerline keel blocks are used in drydocking
operations.

13.3 Section Modulus

Each member is to have a section modulus, SM, in cm3 (in3), not less than that obtained from the following
equation:
SM = M/f cm3 (in3)

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Section 2 Hull Structure 5C-2-2

where
M = maximum bending moment along the member between the toes of the end brackets as
computed by an acceptable method of engineering analysis, in kN-cm (kgf-cm, Ltf-in.)
f = permissible maximum bending stress, as determined from the following table.
Values of f (Ordinary-strength Steel)
kN/cm2 kgf/cm2 Ltf/in2
Transverse members 13.9 1420 9
Longitudinal members 9.3 947 6
Note: Local axial loads on webs, girders or transverses are to be accounted for by reducing the maximum permissible
bending stress.

In addition, the following equation is to be used in obtaining the required section modulus SM.

SM = 4.74chs l 2b cm3 SM = 0.0025chs l 2b in3

c for bottom and deck transverses as shown in 5C-2-2/Figure 1.
= 2.00 for bottom girders, vertical webs on transverse bulkheads, horizontal girders
and stringers
= 2.50 for deck girders
c for side transverses and vertical webs on longitudinal bulkheads
= 1.50 without struts
= 0.85 with one horizontal strut
= 0.65 with two horizontal struts
= 0.55 with three horizontal struts
= Where a centerline longitudinal bulkhead is fitted, the value of c for side-shell
transverses and vertical webs on longitudinal wing bulkheads will be subject to
special consideration.
Where no struts or other effective supporting arrangements are provided for the wing-tank vertical
transverses, the deck transverses in the wing tanks are to have section modulus values not less than 70% of
that for the vertical side transverses. In no case are the deck transverses in the wing tank to have less than
70% of the section modulus for the corresponding members in the center tanks.
s = spacing of transverses, or width of area supported, in m (ft)
h = bottom transverses and girders of the depth of the vessel, D, in m (ft). See also
5C-2-1/1.15.
= side transverses and vertical webs on longitudinal bulkheads, vertical webs on
transverse bulkheads and horizontal girders and stringers, the vertical distance, in
m (ft) from the center of the area supported to a point located 1.22 m (4 ft) above
the deck at side amidships in vessels 61 m (200 ft) in length, and to a point located
2.44 m (8 ft) above the deck at side amidships in vessels 122 m (400 ft) in length and
above; for intermediate lengths, intermediate points may be used. The value of h is to
be not less than the vertical distance from the center of the area supported to the tops
of the hatches, in m (ft). See also 5C-2-1/1.15.
= deck transverses and girders, in m (ft), is to be measured as indicated above for side
transverses, etc., except that in no case is it to be less than 15% of the depth of vessel.

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lb = span of the member, in m (ft), measured between the points of support as indicated in
5C-2-2/Figure 1. Where effective brackets are fitted, the length lb is to be measured
as indicated in 5C-2-2/Figure 2a and 5C-2-2/Figure 2b; nor is the length for deck and
bottom transverses in wing tanks to be less than 0.125B or one-half the breadth of the
wing tank, whichever is the greater. Where a centerline longitudinal bulkhead is also
fitted, this minimum length will be specially considered.

13.5 Local Loading Conditions

In addition to withstanding the loads imposed by longitudinal hull girder shearing and bending action, the
structure is to be capable of withstanding the following local loading conditions without exceeding the
permissible bending and average shearing stresses stated in 5C-2-2/13.3 and 5C-2-2/13.7.
• Center tank loaded; wing tanks empty; 1/3 summer load line draft
• Center tank empty; wing tanks loaded; 1/3 summer load line draft
• Center and wing tanks loaded; 1/3 summer load line draft
Note: For loaded tanks, the head h is to be measured to a point located 2.44 m (8 ft) above the deck at side, except in the
case of vessels less than 122 m (400 ft) in length, as explained in 5C-2-2/13.3. See also 5C-2-1/1.15.
In addition, where the arrangement of the vessel involves tanks of relatively short length, or tanks
designated as permanent ballast tanks, it is recommended that the following appropriate loading conditions
also be investigated:
• Center tank loaded; wing tanks empty; summer load line draft
• Center tank empty; wing tank loaded; summer load line draft
In all cases, the structure is to be reviewed for other realistic loading conditions associated with the
vessel’s intended service.

13.7 Web Portion of Members

The net sectional area of the web portion of the member, including effective brackets where applicable, is
not to be less than that obtained from the following equation.
A = F/q cm2 (in2)
where
F = shearing force at the point under consideration, kN (kgf, Ltf)
q = allowable average shearing stress in the web of the supporting member, as
determined from 5C-2-2/Table 1.
For longitudinal supporting members, the value of q is to be 80% of the value shown in 5C-2-2/Table 1.
Where individual panels exceed the limits given in 5C-2-2/Table 1, detailed calculations are to be submitted
in support of adequate strength against buckling.
The thickness of the web portions of the members is not to be less than given in 5C-2-2/Table 2 for
minimum thickness. Reduced thickness may be considered for higher strength materials if the buckling and
fatigue strength is proven adequate.
It is recommended that compliance with the foregoing requirement be accomplished through a detailed
investigation of the magnitude and distribution of the imposed shearing forces by means of an acceptable
method of engineering analysis. Where this is not practicable, the following equations may be used as
guides in approximating the shearing forces.

F = csD(Kls _ he) for bottom transverses

l s he for lower side transverses or vertical

F = cs[KL lsh _ he(h + − )]
2 2 transverses on longitudinal bulkheads

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l s he for upper side transverses or vertical

F = cs[KU lsh _ he(h _ + )]
2 2 transverses on longitudinal bulkheads
where
c = 10.05 (1025, 0.0285)
s = spacing of transverses, in m (ft)
D = depth of vessel, as defined in 3-1-1/7, in m (ft)
B = breadth of vessel as defined in 3-1-1/5, in m (ft)
ls = span of transverse, in m (ft), as indicated in 5C-2-2/Figure 3
he = effective length or height of bracket, in m (ft), as indicated in 5C-2-2/Figure 3. In no
case is he to be greater than 0.33ls
h = vertical distance, in m (ft), as defined in 5C-2-2/13.3, for the particular member in
question. See also 5C-2-1/1.15.
K = bottom members, K is as shown in 5C-2-2/Figure 3 for the point under consideration
KL = lower side transverses or vertical transverses on longitudinal bulkheads
= 0.65 without struts
= 0.55 with one strut
= 0.43 with two struts
= 0.38 with three or more struts
KU = upper side transverses or vertical transverses on longitudinal bulkheads
= 0.35 without struts
= 0.25 with one strut
= 0.20 with two struts
= 0.17 with three or more struts
Where a centerline longitudinal bulkhead is fitted, the tabulated values of KL and KU will be specially
considered.
The net sectional area of the lower side transverse, as required by the foregoing paragraphs, should be
extended up to the lowest strut, or to 0.33ls, whichever point is the higher. The required sectional area of
the upper side transverse may be extended over the upper 0.33ls of the member.

13.9 Proportions
Webs, girders and transverses are to be not less in depth than required by the following, where the required
depth of member is expressed as a percentage of the span.
12.5% for side and deck transverses, for webs and horizontal girders of longitudinal bulkheads, and for
stringers.
20% for deck and bottom centerline girders, bottom transverses, and webs and horizontal girders of
transverse bulkheads.
The depth of side transverses and vertical webs is to be measured at the middle of lb, as defined in 5C-2-2/13.3,
and the depth may be tapered from bottom to top by an amount not exceeding 8 mm per 100 mm (1 in. per ft).
In no case are the depths of members to be less than three (3) times the depth of the slots for longitudinals.
The thickness of webs is to be not less than required by 5C-2-2/13.7, nor is it to be less than the minimum
thickness given in 5C-2-2/Table 2.

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13.11 Brackets
Brackets are generally to be of the same thickness as the member supported, are to be flanged at their
edges and are to be suitably stiffened.

13.13 Stiffeners and Tripping Brackets

13.13.1 Web Stiffeners
Stiffeners are to be fitted for the full depth of the deep supporting member at the following
intervals, unless specially approved based on the structural stability of deep supporting members:

Location Interval
Bottom every longitudinal
Side every second longitudinal
Bulkhead every second stiffener
Deck every third longitudinal

Special attention is to be given to the stiffening of web plate panels close to change in contour of
web or where higher strength steel is used.
The moment of inertia, I, of the above stiffener, with the effective width of plating not exceeding s
or 0.33l, whichever is less, is not to be less than the following equations:
I = 0.19lt3 (l/s)3 cm4 (in4) for l/s ≤ 2.0
I = 0.38lt3 (l/s)2 cm4 (in4) for l/s > 2.0
where
l = length of stiffener between effective supports, in cm (in.)
t = required thickness of web plating, in cm (in.), but need not be greater than
s/80
s = spacing of stiffeners, in cm (in.)
Web stiffeners are to be attached to the deep webs, longitudinals and stiffeners by continuous fillet
welds.
Where depth/thickness ratio of the web plating exceeds 200, a stiffener is to be fitted parallel to
the flange at approximately one-quarter depth of the web from the face plate. Special attention is
to be given to providing for compressive loads.
13.13.2 Tripping Bracket
Tripping brackets, arranged to support the flanges, are to be fitted at intervals of about 3 m (10 ft),
close to change of section, and in line with or as near as practicable to the flanges of struts.

13.15 Slots and Lightening Holes

Slots and lightening holes, where cut in webs, are to be kept well clear of other openings. The slots are to
be neatly cut and well rounded. Lightening holes are to be located midway between the slots and at about
one-third of the depth of the web from the shell, deck or bulkhead. Their diameters are not to exceed one-
fourth the depth of the web. In general, lightening holes are not to be cut in those areas of webs, girders
and transverses where the shear stresses are high. Similarly, slots for longitudinals are to be provided with
filler plates or other reinforcement in these same areas. Where openings are required in high shear stress
areas, they are to be effectively compensated. Continuous fillet welds are to be provided at the connection
of the filler plates to the web and of the filler plate to the longitudinals.

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Chapter 2 Vessels Intended to Carry Oil in Bulk (Under 150 meters (492 feet) in Length)
Section 2 Hull Structure 5C-2-2

13.17 Struts (1994)

Where one or more struts are fitted as an effective supporting system for the wing-tank members, they are
to be spaced so as to divide the supported members into spans of approximately equal length. The value of
W for struts is obtained from the following equation:
W = nbhs kN (tf, Ltf)
where
n = 10.5 (1.07, 0.03)
b = mean breadth, in m (ft), of the area supported
h = vertical distance, in m (ft), from the center of the area supported to a point located
1.22 m (4 ft) above the deck at side amidships in vessels 61 m (200 ft) in length and
to a point located 2.44 m (8 ft) above the deck at side amidships in vessels 122 m
(400 ft) in length and above; for intermediate lengths, intermediate points may be
used. The value of h is not to be less than the vertical distance, in m (ft), from the
center of the area supported to the tops of the hatches.
The permissible load of struts, Wa, is to be determined by the following equation and is to be equal to or
greater than the calculated W as determined above.

Wa = (k _ nl/r)A kN (tf, Ltf)

where
k = 12.09 (1.232, 7.83) ordinary strength steel
= 16.11 (1.643, 10.43) HT32
= 18.12 (1.848, 11.73) HT36
l = unsupported span of the strut, in cm (ft)
r = least radius of gyration, in cm (in.)
A = cross sectional area of the strut, in cm (in.)
n = 0.0444 (0.00452, 0.345) ordinary strength steel
= 0.0747 (0.00762, 0.581) HT32
= 0.0900 (0.00918, 0.699) HT36
Special attention is to be paid to the end connections for tension members, as well as to the stiffening
arrangements at their ends, to provide effective means for transmission of the compressive forces into the
webs. In addition, horizontal stiffeners are to be located in line with and attached to the first longitudinal
above and below the ends of the struts.

15 Frames, Beams and Bulkhead Stiffeners

15.1 Arrangement
The sizes of the longitudinals or stiffeners as given in this paragraph are based on the transverses or webs
being regularly spaced. Longitudinals or horizontal stiffeners are to be continuous or attached at their ends
to effectively develop their sectional area. This requirement may be modified in the case of stiffeners on
transverse bulkheads. Longitudinals and stiffeners are to be attached to the transverses or webs to
effectively transmit the loads onto these members. Consideration is to be given to the effective support of
the plating in compression when selecting the size and spacing of longitudinals.

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Chapter 2 Vessels Intended to Carry Oil in Bulk (Under 150 meters (492 feet) in Length)
Section 2 Hull Structure 5C-2-2

15.3 Structural Sections

15.3.1 Section Modulus
Each structural section for longitudinal frames, beams or bulkhead stiffeners, in association with
the plating to which it is attached, is to have a section modulus SM not less than obtained from the
following equation:
SM = 7.8chsl2 cm3 SM = 0.0041chsl2 in3
where
c = 1.40 for bottom longitudinals
= 0.95 for side longitudinals
= 1.25 for deck longitudinals
= 1.00 for vertical frames
= 1.00 for horizontal or vertical stiffeners on transverse bulkheads and
vertical stiffeners on longitudinal bulkheads
= 0.90 for horizontal stiffeners on longitudinal bulkheads.
h = distance, in m (ft), from the longitudinals, or from the middle of l for vertical
stiffeners, to a point located 1.22 m (4 ft) above the deck at side amidships in
vessels of 61 m (200 ft) length, and to a point located 2.44 m (8 ft) above the
deck at side amidships in vessels of 122 m (400 ft) length and above; at
intermediate lengths, h is to be measured to intermediate heights above the
side of the vessel. The value of h for bulkhead stiffeners and deck
longitudinals is not to be less than the distance, in m (ft), from the
longitudinal, or stiffener to the top of the hatch. See also 5C-2-1/1.15.
s = spacing of longitudinals or stiffeners, in m (ft)
l = length between supporting points, in m (ft)
The section modulus SM of the bottom longitudinals may be obtained from the above equation
multiplied by R1 where,
15.3.1(a) The bottom hull girder section modulus, SMA, is greater than required by 3-2-1/3.7.1, at
least throughout 0.4L amidships,
15.3.1(b) Still-water bending moment calculations are submitted, and
15.3.1(c) Adequate buckling strength is maintained.
The bottom longitudinals with this modified section modulus are to meet all other Rule requirements.

R1 = n/[n + fp(1 _ SMR /SMA )] but is not to be taken less than 0.69
where
n = 7.69 (0.784, 4.978)
fp = nominal permissible bending stress, as given in 3-2-1/3.7.1
SMR = hull girder section modulus required by 3-2-1/3.7.1, in cm2-m (in2-ft)
SMA = bottom hull girder section modulus, cm2-m (in2-ft), with the longitudinals
modified as permitted above.
Where the heavy ballast draft forward is less than 0.04L, the flat of bottom forward longitudinals
are not to be less than required by 3-2-4/13.5.
15.3.2 Web Thickness (1993)
In addition to the requirements in 3-1-2/13.5.2, the thickness of web portion is to be not less than
the thickness given in 5C-2-2/Table 2, reduced by 1.0 mm (0.04 in.).

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Part 5C Specific Vessel Types
Chapter 2 Vessels Intended to Carry Oil in Bulk (Under 150 meters (492 feet) in Length)
Section 2 Hull Structure 5C-2-2

15.5 Bilge Longitudinals

Longitudinals around the bilge are to be graded in size from that required for the lowest side longitudinals
to that required for the bottom longitudinals.

15.7 Vessels under 76 m (250 ft)

In vessels under 76 m (250 ft) in length, the coefficient c for use in the above equation for bottom
longitudinals may be reduced to 1.30.

17 Structure at Ends
Beyond the cargo spaces, the scantlings of the structure may be as required in way of the oil spaces, in
association with the values of h in the various equations measured to the upper deck, except that in way of
deep tanks, h is to be not less than the distance, in m (ft), measured to the top of the overflow. In way of
dry spaces, the deck beams and longitudinals are to be as required in Section 3-2-7. The value of h for
deck transverses in way of dry spaces is to be obtained from Section 3-2-7 and the section modulus SM is
to be obtained from the following equation:
SM = 4.74chsl2 cm3 SM = 0.0025chsl2 in3
where
c = 1.23
s = spacing of transverses, in m (ft)
l = span, in m (ft)
The transition from longitudinal framing to transverse framing is to be effected in as gradual a manner as
possible, and it is recommended that a system of closely spaced transverse floors be adopted in way of the
main machinery.

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Part 5C Specific Vessel Types
Chapter 2 Vessels Intended to Carry Oil in Bulk (Under 150 meters (492 feet) in Length)
Section 2 Hull Structure 5C-2-2

FIGURE 1
Coefficients and Lengths for Transverses
L
C
c = 2.50 c = 3.50
L bhd
C
c = 1.80

lb lb
lb

lb

lb lb lb

c = 2.40
c = 1.50
c = 1.75 for CL girder only
c = 1.15 for three girders
a b
L
C
c = 1.80

lb

lb

c = 1.50
c

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Part 5C Specific Vessel Types
Chapter 2 Vessels Intended to Carry Oil in Bulk (Under 150 meters (492 feet) in Length)
Section 2 Hull Structure 5C-2-2

FIGURE 2
Lengths with Brackets

lb

d/4

he

Where face plate area on the member is

carried along the face of the bracket
a

lb

d/2

he

Where face plate area on the member is not

carried along the face of the bracket, and
where face plate area on the bracket is at
least one-half the face plate area on the
member
b

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Part 5C Specific Vessel Types
Chapter 2 Vessels Intended to Carry Oil in Bulk (Under 150 meters (492 feet) in Length)
Section 2 Hull Structure 5C-2-2

FIGURE 3
Spans of Members and Effective Lengths or Heights of Brackets
L
C L bhd
C

he

ls ls ls
ls

he he
he
he

K = 0.60 K = 0.60 K = 0.25 B/ls

but not less than 0.50
a b

L
C L
C

ls ls

he

K = 0.50
K = 0.43
c d

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Part 5C Specific Vessel Types
Chapter 2 Vessels Intended to Carry Oil in Bulk (Under 150 meters (492 feet) in Length)
Section 2 Hull Structure 5C-2-2

TABLE 1
Values of q for Ordinary Strength Steel
s = spacing of stiffeners or depth of web plate, whichever is the lesser, in cm (in.)
t = thickness of web plate, in cm (in.)
s/t kN/cm2 kgf/cm2 Ltf/in2
80 and less 8.5 870 5.5
160 maximum 5.4 550 3.5

TABLE 2
Minimum Thickness for Web Portions of Members
L is the length of the vessel, in m (ft), as defined in 3-1-1/3. For vessels of lengths intermediate to those shown in the
table, the thickness is to be obtained by interpolation.
L t L t
meters mm feet in.
61 8.5 200 0.34
82 9 270 0.36
118 10 390 0.40
150 11 492 0.44

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PART Section 3: Cargo Oil and Associated Systems

5C
CHAPTER 2 Vessels Intended to Carry Oil in Bulk (Under 150
meters (492 feet) in Length)

SECTION 3 Cargo Oil and Associated Systems

See Section 5C-1-7.

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PART Appendix 1: Guide for Hull Girder Shear Strength for Tankers

5C
CHAPTER 2 Vessels Intended to Carry Oil in Bulk (Under 150
meters (492 feet) in Length)

APPENDIX 1 Guide for Hull Girder Shear Strength for Tankers

1 Introduction
This Guide is a supplement to 3-2-1/3.5 of the Rules and is intended to provide a simplified method for
determining the allowable still-water shearing forces, in accordance with the Rule requirements, for
tankers having two or three longitudinal oil-tight bulkheads, where the wing bulkheads are located no
closer than 20% of the breadth from the side shell.
The computational method presented in this Guide is deduced from shear flow and three-dimensional finite
element calculation results and is applicable to tankers having single bottom construction with deep bottom
transverses and swash transverse bulkheads. For tankers having either double bottom, double skin or deep
bottom girders, the allowable still-water shearing force will be subject to special consideration.
With the present Rule side shell thickness, local load effects are not considered for the side shell, as the
longitudinal bulkhead generally governs the permissible shear force at any particular location.

3 Allowable Still-water Shearing Force

The allowable still-water shearing force, in kN (tf, Ltf), at any transverse section of the vessel is the lesser
of the SWSF obtained from 5C-2-A1/3.1 and 5C-2-A1/3.3 with any applicable modification as specified in
5C-2-A1/3.5.

3.1 Considering the Side Shell Plating

0.935 f s t s D s _
SWSF = Fw
Ns

3.3 Considering Various Longitudinal Bulkhead Plating

1.05 f s t b Db _
SWSF = Fw
K1 N b
In general, in the absence of a local load, two locations need be checked for each bulkhead: the lower edge
of the thinnest strake and at the neutral axis of the section. When a local load is present, the SWSF should
be computed at the base of each longitudinal bulkhead strake for use with 5C-2-A1/3.5. For vessels having
three longitudinal bulkheads, the SWSF should be calculated considering both the centerline and wing
bulkheads.
Fw = wave induced shear force, as specified by 3-2-1/3.5.2 of the Rules, in kN (tf, Ltf)
fs = permissible total shear stress, as specified in 3-2-1/3.9.1 of the Rules, in kN/cm2
(tf/cm2, Ltf/in2)
ts = thickness of the side shell plating at the neutral axis of the section in, cm (in.)
tb = thickness of the centerline or wing longitudinal bulkhead plating at the location under
consideration, in cm (in.)

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Chapter 2 Vessels Intended to Carry Oil in Bulk (Under 150 meters (492 feet) in Length)
Appendix 1 Guide for Hull Girder Shear Strength for Tankers 5C-2-A1

Ds = depth of the hull girder at the section under consideration, in cm (in.)

Db = depth of the longitudinal bulkhead at the section under consideration, in cm (in.)
Ns, Nb = shear distribution factors for side shell and longitudinal bulkheads, respectively, and
may be determined by 5C-2-A1/5.
K1 = 1 + y/(8 y )
y = distance measured from the deck or bottom (depending on whether the strake considered
is above or below the neutral axis of the section) to the lower edge of the bulkhead
strake under consideration, in cm (in.)
y = distance measured from the deck (bottom) to the neutral axis of the section, when the
strake under consideration is above (below) the neutral axis, in cm (in.)

3.5 Reduction for Local Loads

When the loading head in the center tank is different from that in an adjacent wing tank, then the allowable
SWSF computed at the various bulkhead locations in 5C-2-A1/3.3 may have to be reduced, as follows.
3.5.1
For the case of a two longitudinal bulkhead vessel, when the center tank head is less than that in
any adjacent wing tank, no reduction need be made.
3.5.2
For two and three bulkhead vessels, when the center tank head exceeds that in a wing tank, within
the center tank region, a hull girder shear force reduction, R, should be computed at the corresponding
locations on the bulkheads used in 5C-2-A1/3.3. These reductions should be determined for both
wing and centerline bulkheads, and may be calculated as follows.
⎛ 2.1K 2 N w ⎞
R = Wc ⎜⎜ − 1⎟⎟ kN (tf, Ltf)
⎝ 3K 1 N b ⎠
If 2.1K2Nw is less than or equal to 3K1Nb, R should be taken as zero.
K1, Nb = as previously defined
Nw = distribution factor for local loads, as specified in 5C-2-A1/5
K2 = 1 + (A/Ab)
A = total area of the longitudinal bulkhead plating above the lower edge of the
strake under consideration, in cm2 (in2)
Ab = total area of the longitudinal bulkhead plating under consideration, in cm2 (in2)
Wc = effective local load which may be denoted by Wc1 and Wc2, at the fore and aft
ends of the center tank, respectively

wbc ⎡ ⎛ l1 ⎞ l 22 ⎤
Wc1 = ⎢hc1l 1 ⎜ l 2 + ⎟ + hc 2 ⎥
lc ⎢⎣ ⎝ 2⎠ 2 ⎥⎦

wbc ⎡ l 12 ⎛ l ⎞⎤
Wc2 = ⎢hc1 + hc 2 l 2 ⎜ l 1 + 2 ⎟ ⎥
l c ⎣⎢ 2 ⎝ 2 ⎠ ⎥⎦

w = density of the cargo (ballast), in kgf/m3 (tf/m3, Ltf/ft3)

lc, bc = length and breadth, respectively, of the center tank, in m (ft)
hc1, hc2 = excess fluid heads in the center tank. Should the head in a wing tank exceed
that in the center tank, see 5C-2-A1/3.5.3 below.
l1, l2 = longitudinal distances from the respective center tank ends to the succeeding
wing tank transverse bulkheads

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Chapter 2 Vessels Intended to Carry Oil in Bulk (Under 150 meters (492 feet) in Length)
Appendix 1 Guide for Hull Girder Shear Strength for Tankers 5C-2-A1

3.5.3
When the head in wing tanks exceeds that in the center tank, within the center tank region, hc
should be taken as zero for two longitudinal bulkhead vessels. However, a reduction should be
applied only to the SWSF computed while considering the centerline bulkhead in 5C-2-A1/3.3.
This reduction may be computed by the equations in 5C-2-A1/3.5.2, except that bc is to be taken
as the combined breadth of both wing tanks (bc = 2bw), and hc is the excess head in the wing tank
above that in the center tank.
3.5.4
Where adjacent tanks are loaded with cargoes of different densities, the heads in 5C-2-A1/3.5 are
to be corrected to account for the difference in density.

5 Distribution Factors
The distribution factors Ns, Nb and Nw may be determined by the following equations.

5.1 For Vessels Having Two Longitudinal Bulkheads

Nb = 0.32 _ 0.06(As/Ab)
N = 0.5 _ N
s b

Nw = 0.31(n _ 1)/n
where
As = total projected area of the side shell plating, in cm2 (in2)
Ab = as previously defined
n = total number of transverse frame spaces in the center tank

5.3 For Vessels Having Three Longitudinal Bulkheads

Nb (center) = 0.26 _ 0.044(As /Ab) + C1
N (wing) = 0.25 _ 0.044(A /A ) _ C
b s b 2

Ns = 0.5 _ 0.5Nb (center) _ Nb (wing)

Nw (center) = (0.7N + 0.15)(n _ 1)/n
b

Nw (wing) = (1.5Nb _ 0.1)(n _ 1)/n

As, Ab, n are as previously defined, however, Ab should be either the center or wing bulkhead area, depending
on which is being considered.
C1 = 0 for K > 0.9
C1 = 0.1 (1 _ K) _ 0.005 for K ≤ 0.9
K = Ab (wing)/Ab (center)
C2 = 0 for K > 0.9
C2 = 0.04 (1 _ K) for K ≤ 0.9

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Part 5C Specific Vessel Types
Chapter 2 Vessels Intended to Carry Oil in Bulk (Under 150 meters (492 feet) in Length)
Appendix 1 Guide for Hull Girder Shear Strength for Tankers 5C-2-A1

FIGURE 1
Center Tank Region
lc

l2 l1

bw

Longitudinal wing bulkhead

bc
Centerline bulkhead

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PART Chapter 3: Vessels Intended to Carry Ore or Bulk Cargoes (150 meters (492 feet) or more in Length)

5C
CHAPTER 3 Vessels Intended to Carry Ore or Bulk Cargoes
(150 meters (492 feet) or more in Length)

CONTENTS
SECTION 1 Introduction ........................................................................................ 299
1 General ...........................................................................................299
1.1 Classification ...............................................................................299
1.2 Optional Class Notation for Design Fatigue Life ..........................299
1.3 Application ...................................................................................300
1.5 Definitions....................................................................................301
1.7 Section Properties of Structural Members ...................................302
1.9 Protection of Structure .................................................................303
3 Arrangement ...................................................................................304
3.1 General........................................................................................304
3.3 Subdivision and Damage Stability ...............................................304
3.5 Special Requirements for Deep Loading .....................................304
5 Carriage of Oil Cargoes ..................................................................304
5.1 General........................................................................................304
5.3 Gas Freeing .................................................................................304
5.5 Slop Tanks...................................................................................304
7 Forecastle .......................................................................................304
7.1 General........................................................................................304
7.3 Arrangements ..............................................................................304
7.5 Dimensions..................................................................................305
7.7 Structural Arrangements and Scantlings .....................................305

TABLE 1 Minimum Material Grades for Single-side Skin Bulk

Carriers Subject to SOLAS Regulation XII/6.5.3 ..................300

FIGURE 1.....................................................................................................302
FIGURE 2.....................................................................................................302
FIGURE 3.....................................................................................................302
FIGURE 4.....................................................................................................302
FIGURE 5.....................................................................................................303
FIGURE 6.....................................................................................................305

286 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
 SECTION 2 Design Considerations and General Requirements........................ 306
1 General Requirements....................................................................306
1.1 General........................................................................................ 306
1.3 Initial Scantling Requirements ..................................................... 306
1.5 Strength Assessment – Failure Modes........................................ 306
1.7 Structural Redundancy and Residual Strength............................ 306
1.9 Strength Assessment in the Flooded Condition........................... 307
3 Nominal Design Corrosion Values (NDCV) ....................................307
3.1 General........................................................................................ 307

TABLE 1 Nominal Design Corrosion Values (NDCV) for Bulk

Carriers .................................................................................309

FIGURE 1 Nominal Design Corrosion Values (NDCV) ..........................308

SECTION 3 Load Criteria ....................................................................................... 310

1 General ...........................................................................................310
1.1 Load Components ....................................................................... 310
3 Static Loads ....................................................................................310
3.1 Still-water Bending Moments and Shear Forces ......................... 310
3.3 Bulk Cargo Pressures ................................................................. 310
5 Wave-Induced Loads ......................................................................312
5.1 General........................................................................................ 312
5.3 Additional Wave Induced Moments and Shear Force ................. 312
5.5 External Pressures ...................................................................... 313
5.7 Internal Pressures – Inertia Forces and Added Pressure
Heads .......................................................................................... 316
7 Nominal Design Loads....................................................................329
7.1 General........................................................................................ 329
7.3 Hull Girder Loads – Longitudinal Bending Moments and Shear
Forces ......................................................................................... 329
7.5 Local Loads for Design of Supporting Structures ........................ 330
7.7 Local Pressures for Design of Plating and Longitudinals ............ 330
9 Combined Load Cases ...................................................................336
9.1 Combined Load Cases for Structural Analysis ............................ 336
9.3 Combined Load Cases for Total Strength Assessment ............... 336
11 Impact Loads ..................................................................................338
11.1 Bottom Slamming ........................................................................ 338
11.3 Bowflare Slamming ..................................................................... 340
11.5 Load Cases for Structural Analysis with Respect to
Slamming .................................................................................... 343
13 Other Loads ....................................................................................343
13.1 Thermal and Ice Loads................................................................ 343
13.3 Accidental Loads ......................................................................... 343

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 TABLE 1 Combined Load Cases for Bulk, Ore/Bulk/Oil and Ore/Oil
Carriers .................................................................................328
TABLE 2 Values of Ai and Bi ................................................................329
TABLE 3 Design Pressure for Local and Supporting Members ...........332
TABLE 4 Values of α ............................................................................339

FIGURE 1 Loading Pattern of Conventional Bulk Carrier ......................311

FIGURE 2 Distribution Factor mh ............................................................322
FIGURE 3 Distribution Factor fh ..............................................................322
FIGURE 4 Distribution of hdi....................................................................323
FIGURE 5 Pressure Distribution Function klo .........................................323
FIGURE 6 Distribution Factor mT ............................................................324
FIGURE 7 Definition of Bow Geometry ..................................................324
FIGURE 8 Direction of Positive Tangential Force ..................................325
FIGURE 9 Definition of Wall Angle.........................................................325
FIGURE 10 Definition of Cargo Height at Various Locations ...................326
FIGURE 11 Definition of Wall Angle for Transverse Bulkhead ................326
FIGURE 12 Definition of Tank Geometry .................................................327
FIGURE 13 Location of Hold for Nominal Pressure Calculation ..............331
FIGURE 14 Illustration of Determining Total External Pressure ..............337
FIGURE 15 Distribution of Bottom Slamming Pressure Along the
Section Girth .........................................................................344
FIGURE 16 Distribution of Bottom Slamming Pressure Along the Ship
Bottom...................................................................................344
FIGURE 17 Total Vertical Bending Moment Distribution (Wave and
Bottom Slamming).................................................................345
FIGURE 18 Definition of Bowflare Geometry for Bowflare Shape
Parameter .............................................................................346
FIGURE 19 Ship Stem Angle, γ................................................................346
FIGURE 20 Total Vertical Bending Moment Distribution (Wave and
Bowflare Slamming) ..............................................................347
FIGURE 21 Total Vertical Shear Force Distribution (Wave and
Bowflare Slamming) ..............................................................347

SECTION 4 Initial Scantling Criteria ..................................................................... 348

1 General ...........................................................................................348
1.1 Strength Requirement..................................................................348
1.3 Calculation of Load Effects ..........................................................348
1.5 Structural Details .........................................................................348
1.7 Evaluation of Grouped Stiffeners .................................................349
3 Hull Girder Strength ........................................................................351
3.1 Hull Girder Section Modulus ........................................................351
3.3 Hull Girder Moment of Inertia.......................................................351
5 Shearing Strength ...........................................................................351
5.1 General........................................................................................351
5.3 Net Thickness of Side Shell Plating .............................................352

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 5.5 Net Thickness of the Sloping Bulkhead Plating of Upper and
Lower Wing Tanks....................................................................... 353
5.7 Net Thickness of the Inner Hull Plating ....................................... 353
5.9 Three Dimensional Analysis ........................................................ 353
7 Double Bottom Structures...............................................................353
7.1 General........................................................................................ 353
7.3 Bottom Shell and Inner Bottom Plating........................................ 354
7.5 Bottom and Inner Bottom Longitudinals ...................................... 361
7.7 Bottom Centerline Girder............................................................. 362
7.9 Bottom Side Girders .................................................................... 363
7.11 Bottom Floors .............................................................................. 364
7.13 Deep Tank Double Bottom Girder ............................................... 365
7.15 Double Bottom Shear Capacity in Flooded Condition ................. 365
9 Side Shell Plating and Longitudinals ..............................................369
9.1 Side Shell Plating ........................................................................ 369
9.3 Side Longitudinals ....................................................................... 372
11 Side Frames and Supporting Structures.........................................373
11.1 General........................................................................................ 373
11.3 Frame Section Modulus............................................................... 374
11.5 Frame Sections ........................................................................... 375
11.7 Brackets ...................................................................................... 375
11.9 Longitudinals at the Toe of Brackets ........................................... 376
13 Side Transverses/Web Frames and Transverse Webs in Lower
and Upper Wing Tanks ...................................................................376
13.1 General........................................................................................ 376
13.3 Transverses in Lower Wing Tank ................................................ 377
13.5 Transverses in Upper Wing Tank in Way of Dry Cargo Holds..... 378
13.7 Transverses in Upper Wing Tank in Way of Ballast or Liquid
Cargo Holds ................................................................................ 380
13.9 Minimum Thickness for Web Portion of Main Supporting
Members ..................................................................................... 382
13.11 Vertical Diaphragms and Side Stringers in Double Hull Side
Tanks or Void Space ................................................................... 382
15 Deck Plating and Longitudinals/Beams ..........................................387
15.1 Main Deck Plating ....................................................................... 387
15.3 Main Deck Longitudinals ............................................................. 388
15.5 Cross Deck Plating ...................................................................... 388
15.7 Cross Deck Beams...................................................................... 389
15.9 Stiffness of Cross Deck Structures.............................................. 390
17 Deck Girders and Main Supporting Members.................................392
17.1 General........................................................................................ 392
17.3 Hatch Side Girders ...................................................................... 392
17.5 Hatch-End Beams ....................................................................... 392
17.7 Deck Girders Inside the Lines of Hatch Openings....................... 394
17.9 Minimum Thickness for Web Portion of Main Supporting
Members ..................................................................................... 395

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 19 Cargo Hold Hatch Covers, Hatch Coamings and Closing
Arrangements..................................................................................397
19.1 Application ...................................................................................397
19.3 Hatch Covers ...............................................................................397
19.5 Hatch Coamings ..........................................................................404
19.7 Closing Arrangements .................................................................408
21 Longitudinal Bulkheads...................................................................409
21.1 Sloping Bulkhead Plating of Lower Wing Tank ............................409
21.3 Sloping Bulkhead Plating of Upper Wing Tank ............................411
21.5 Non-tight Bulkhead in Upper Wing Tank Where Adjacent to
Cargo Hold ..................................................................................413
21.7 Non-tight Bulkhead in Upper Wing Tank where Adjacent to
Ballast or Liquid Cargo Hold ........................................................413
21.9 Inner Hull Longitudinal Bulkhead .................................................414
21.11 Longitudinal and Vertical Stiffeners .............................................416
23 Plane Transverse Bulkheads ..........................................................417
23.1 Plating..........................................................................................417
23.3 Vertical and Horizontal Stiffeners.................................................417
23.5 Horizontal Girder on Transverse Bulkhead..................................418
23.7 Vertical Web on Transverse Bulkhead.........................................419
25 Corrugated Transverse Bulkhead...................................................421
25.1 General........................................................................................421
25.3 Plating..........................................................................................421
25.5 Stiffness of Corrugation ...............................................................422
25.7 Flooded Conditions......................................................................424
25.9 Bulkhead Lower Stool..................................................................425
25.11 Bulkhead Upper Stool..................................................................426
25.13 Bulkhead Stool Alignment............................................................426
25.15 Bulkhead End Connection ...........................................................426

TABLE 1 Parameters m and β as functions of n and l/sf ......................360

FIGURE 1 Scantling Requirement Reference by Subsection ................349

FIGURE 2 Improved Structural Connection to Side Shell ......................350
FIGURE 2A ..................................................................................................354
FIGURE 3 Unsupported Span of Longitudinal........................................366
FIGURE 4 Effective Breadth of Plating be ...............................................367
FIGURE 5 Definition of ls and bs .............................................................368
FIGURE 6 Definitions of Parameters for Hold Frame ............................384
FIGURE 7.....................................................................................................385
FIGURE 8.....................................................................................................385
FIGURE 9 Transverses in Wing Tanks Definition of Span.....................386
FIGURE 10 Cross Deck Structure ............................................................391
FIGURE 11 Definition of Parameters for Corrugated Bulkhead ...............395
FIGURE 12 Effectiveness of Brackets......................................................396
FIGURE 13...................................................................................................406
FIGURE 14...................................................................................................406

290 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
 FIGURE 15...................................................................................................407
FIGURE 16...................................................................................................407
FIGURE 17 Transverse Bulkheads – Definitions of Spans ......................420
FIGURE 18 Definition of Parameters for Corrugated Bulkhead ...............428
FIGURE 19 Corrugated Bulkhead End Connections ...............................428
FIGURE 20 Extension of Lower Stool Top Plate......................................429
FIGURE 21 Full/Deep Penetration Welding .............................................429

SECTION 5 Total Strength Assessment............................................................... 430

1 General Requirements....................................................................430
1.1 General........................................................................................ 430
1.3 Loads and Load Cases ............................................................... 430
1.5 Stress Components ..................................................................... 430
3 Yielding Criteria...............................................................................431
3.1 General........................................................................................ 431
3.3 Structural Members and Elements .............................................. 431
3.5 Plating ......................................................................................... 432
5 Buckling and Ultimate Strength Criteria..........................................432
5.1 General........................................................................................ 432
5.3 Plate Panels ................................................................................ 433
5.5 Longitudinals and Stiffeners ........................................................ 435
5.7 Stiffened Panels .......................................................................... 436
5.9 Deck Girders and Webs .............................................................. 436
5.11 Corrugated Bulkheads................................................................. 437
5.13 Hull Girder Ultimate Strength....................................................... 438
7 Fatigue Life .....................................................................................441
7.1 General........................................................................................ 441
7.3 Procedures .................................................................................. 441
7.5 Spectral Analysis......................................................................... 442
9 Calculation of Structural Responses...............................................442
9.1 Methods of Approach and Analysis Procedures.......................... 442
9.3 3D Finite Element Models ........................................................... 442
9.5 2D Finite Element Models ........................................................... 443
9.7 Local Structural Models ............................................................... 443
9.9 Load Cases ................................................................................. 443

TABLE 1 Combined Load Cases to be Investigated for Each

Structural Member ................................................................443

FIGURE 1.....................................................................................................440

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 291
 SECTION 6 Hull Structure Beyond 0.4L Amidships ............................................ 444
1 General Requirements....................................................................444
1.1 General........................................................................................444
1.3 Structures within Cargo Spaces...................................................444
3 Bottom Shell Plating and Stiffeners in Forebody ............................444
3.1 Bottom Shell Plating ....................................................................444
3.3 Bottom Longitudinals/Stiffeners ...................................................446
3.5 Bottom Girders and Floors...........................................................446
5 Side Shell Plating and Stiffeners in Forebody ................................449
5.1 General........................................................................................449
5.3 Plating Forward of Forepeak Bulkhead........................................449
5.5 Plating between Forepeak Bulkhead and 0.125L from the FP.....450
5.7 Plating between 0.3L and 0.125L from the FP.............................450
5.9 Plating in Upper and Lower Wing Tanks......................................450
5.11 Side Frames and Longitudinals Forward of 0.3L from the FP......451
5.13 Hold Frames ................................................................................452
5.15 Hold Frames in the Foremost Cargo Hold ...................................452
7 Side Transverses and Stringers in Forebody .................................454
7.1 Section Modulus ..........................................................................454
7.3 Sectional Area of Web .................................................................457
7.5 Depth of Transverse/Stringer.......................................................459
7.7 Thickness ....................................................................................459
9 Deck Structures in Forebody ..........................................................461
9.1 General........................................................................................461
9.3 Deck Plating ................................................................................461
9.5 Deck Longitudinals/Beams ..........................................................461
9.7 Cross Deck Beams ......................................................................461
9.9 Hatch End Beams........................................................................462
9.11 Deck Girders Inside the Lines of Hatch Opening .........................462
9.13 Deck Transverse in Upper Wing Tank .........................................462
11 Transition Zone ...............................................................................462
11.1 General........................................................................................462
13 Forebody Strengthening for Slamming ...........................................463
13.1 General........................................................................................463
13.3 Bottom Slamming ........................................................................463
13.5 Bowflare Slamming......................................................................465

FIGURE 1 Double Bottom Structure in Forebody Region ......................448

FIGURE 2 Transverse Distribution of pd .................................................453
FIGURE 3 Arrangement of Tripping Brackets for Hold Frames with
Asymmetric Sections.............................................................453
FIGURE 4 Definition of Spans ................................................................460
FIGURE 5 Transition Zone .....................................................................463

292 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
 SECTION 7 Cargo Safety and Vessel Systems.................................................... 467
1 Application ......................................................................................467
3 Bulk Cargo Spaces .........................................................................467
3.1 Fire Protection ............................................................................. 467
3.3 Vessels Carrying Low Fire Risk Cargoes .................................... 467
3.5 Vessels Intended to Carry Solid Dangerous Goods in Bulk......... 468
3.7 Vessels Intended to Carry Coal in Bulk ....................................... 470
3.9 Vessels Intended to Carry Materials Hazardous Only in Bulk ..... 471
3.11 Cable Support ............................................................................. 471
5 Hold Piping......................................................................................471
7 Self-unloading Cargo Gear .............................................................471
7.1 Fail-safe Arrangements and Safety Devices ............................... 471
7.3 Hydraulic Piping Installations....................................................... 471
7.5 Equipment in Hazardous Areas................................................... 472
7.7 Self-unloading Gear Controls and Alarms ................................... 472
9 Draining and Pumping Forward Spaces in Bulk Carriers ...............472
9.1 Application................................................................................... 472
9.3 Availability of Pumping Systems for Forward Spaces ................. 472
9.5 Dewatering Capacity ................................................................... 472

TABLE 1 Dangerous Goods Classes ...................................................469

TABLE 2 Application of the Requirements to Different Classes of
Solid Dangerous Goods in Bulk ............................................469

APPENDIX 1 Guide for Fatigue Strength Assessment of Bulk Carriers .............. 473
1 General ...........................................................................................473
1.1 Note............................................................................................. 473
1.3 Applicability ................................................................................. 473
1.5 Loadings...................................................................................... 473
1.7 Effects of Corrosion..................................................................... 473
1.9 Format of the Criteria .................................................................. 474
3 Connections to be Considered for the Fatigue Strength
Assessment ....................................................................................474
3.1 General........................................................................................ 474
3.3 Guidance on Locations................................................................ 474
5 Permissible Stress Range...............................................................480
5.1 Assumptions................................................................................ 480
5.3 Criteria......................................................................................... 480
5.5 Long Term Stress Distribution Parameter, γ ................................ 480
5.7 Permissible Stress Range ........................................................... 481
7 Fatigue Inducing Loads...................................................................484
7.1 General........................................................................................ 484
7.3 Wave-induced Loads................................................................... 484
7.5 Fatigue Assessment Zones and Controlling Load
Combination ................................................................................ 484
7.7 Primary Stress fd1 ........................................................................ 485
7.9 Secondary Stress f d2 ................................................................... 485

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 293
 7.11 Additional Secondary Stresses f* d2 and Tertiary Stresses fd3 ......487
7.13 Calculation of Stress Range for Hold Frame ...............................489
9 Resulting Total Stress Ranges .......................................................495
9.1 Definitions....................................................................................495
11 Determination of Stress Concentration Factors (SCFs) .................496
11.1 General........................................................................................496
11.3 Sample Stress Concentration Factors (SCFs).............................496
13 Stress Concentration Factors Determined From Finite Element
Analysis...........................................................................................505
13.1 Introduction..................................................................................505
13.3 S-N Data......................................................................................505
13.5 S-N Data and SCFs .....................................................................506
13.7 Calculation of Hot Spot Stress for Fatigue Analysis of Ship
Structures ....................................................................................508

TABLE 1 Fatigue Classification for Structural Details ..........................476

TABLE 1A Coefficient, C.........................................................................481
TABLE 2 Coefficient k2b for Double Bottom Panels when ρb ≥ 1.0 .......490
TABLE 3 Coefficient kb′ for Double Bottom Panels when ρb ≤ 1.0 .......490
TABLE 4 Coefficient k3b for Double Bottom Panels ..............................490
TABLE 5 Coefficient k2s for Double Side Panels when ρs ≥ 1.0............492
TABLE 6 Coefficient ks′ for Double Side Panels when γs ≤ 1.0.............492
TABLE 7 Coefficient k3s for Double Side Panels ..................................492
TABLE 8 Ks (SCF) Values ....................................................................496

FIGURE 1 Basic Design S-N Curves .....................................................482

FIGURE 2 Dimensions of Double Bottom, Double Side.........................491
FIGURE 3 Cn = Cn (ψ) .............................................................................493
FIGURE 4 Hold Frame ...........................................................................494
FIGURE 5 Cut-outs (Slots) For Longitudinal ..........................................498
FIGURE 6 Fatigue Classification for Longitudinals in way of Flat Bar
Stiffener.................................................................................500
FIGURE 7 Connection of Longitudinal and Stiffener ..............................501
FIGURE 8 Connection Between Corrugated Transverse Bulkhead
and Deck ...............................................................................501
FIGURE 9 Connection between Corrugated Transverse Bulkhead
and Inner Bottom with Respect to Lateral Load on the
Bulkhead ...............................................................................502
FIGURE 10 Connection between Inner Bottom and Hopper Tank
Slope .....................................................................................503
FIGURE 11 Hatch Corner.........................................................................503
FIGURE 12 Hold Frames..........................................................................504
FIGURE 13 Doublers and Non-load Carrying Members on Deck or
Shell Plating ..........................................................................505
FIGURE 14...................................................................................................507
FIGURE 15...................................................................................................507
FIGURE 16...................................................................................................508
FIGURE 17...................................................................................................509

294 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
 APPENDIX 2 Calculation of Critical Buckling Stresses ........................................ 510
1 General ...........................................................................................510
3 Rectangular Plates..........................................................................510
5 Longitudinals, Stiffeners, Hold Frames and Unit Corrugation for
Transverse Bulkhead ......................................................................513
5.1 Axial Compression ...................................................................... 513
5.3 Torsional/Flexural Buckling ......................................................... 513
5.5 Buckling Criteria for Unit Corrugation of Transverse
Bulkhead ..................................................................................... 514
7 Stiffened Panels..............................................................................516
7.1 Large Stiffened Panels ................................................................ 516
7.3 Corrugated Transverse Bulkheads.............................................. 517
9 Deep Girders, Webs and Stiffened Brackets ..................................518
9.1 Critical Buckling Stresses of Web Plates and Large Brackets..... 518
9.3 Effects of Cut-outs ....................................................................... 518
9.5 Tripping ....................................................................................... 518
11 Stiffness and Proportions................................................................519
11.1 Stiffness of Longitudinals............................................................. 519
11.3 Stiffness of Web Stiffeners .......................................................... 520
11.5 Stiffness of Supporting Members ................................................ 520
11.7 Proportions of Flanges and Face Plates...................................... 520
11.9 Webs of Longitudinals and Stiffeners .......................................... 520

TABLE 1 Buckling Coefficient, Ki .........................................................511

FIGURE 1 Net Dimensions and Properties of Stiffeners........................515

FIGURE 2.....................................................................................................517

APPENDIX 3 The Design and Evaluation of Ore and Ore/Oil Carriers ................. 521
1 General ...........................................................................................521
3 Nominal Design Corrosion Values..................................................521
5 Loading Patterns.............................................................................521
7 Strength Criteria..............................................................................521
9 Cargo Loading ................................................................................523
9.1 General........................................................................................ 523
9.3 Evaluation Procedure .................................................................. 523
9.5 Target Loading Processes........................................................... 523
9.7 Compliance with Allowable Still-Water Loading Limits ................ 524
9.9 Compliance with Allowable Mass Curves .................................... 524
9.11 Intermediate Calculations ............................................................ 524
9.13 Total Strength Assessment against Cargo Overshooting ............ 525
9.15 Vessels Carrying Ore Cargoes with SH Notation ........................ 525
9.17 Ballast System............................................................................. 525
9.19 Automatic Draft Reading Sensors and Automatic Level-
Gauging System.......................................................................... 525

FIGURE 1 Loading Pattern of Ore/Oil Carrier ........................................522

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 295
 APPENDIX 4 Load Cases for Structural Analysis with Respect to Slamming..... 526
1 Bowflare Slamming .........................................................................526
1.1 Load Case – A .............................................................................526
1.3 Load Case – B .............................................................................526
1.5 Hull Girder Loads.........................................................................526
1.7 External Pressures ......................................................................526
1.9 Internal Bulk and Ballast Pressures .............................................526
1.11 Reference Wave Heading and Position .......................................528
3 Bottom Slamming............................................................................528
3.1 Load Case – C.............................................................................528
3.3 Hull Girder Loads.........................................................................528
3.5 External Pressures ......................................................................528
3.7 Internal Ballast Pressures (no bulk pressure) ..............................528
3.9 Reference Wave Heading and Position .......................................528

FIGURE 1 Loading Patterns for Slamming Study ..................................527

APPENDIX 5a Longitudinal Strength of Bulk Carriers in Flooded Condition........ 529

1 General ...........................................................................................529
1.1 Application ...................................................................................529
1.3 Loading Conditions ......................................................................529
3 Flooding Conditions ........................................................................529
3.1 Floodable Holds...........................................................................529
3.3 Loads...........................................................................................529
3.5 Flooding Criteria ..........................................................................529
5 Strength Assessment......................................................................530
5.1 Stress Calculation........................................................................530
5.3 Strength Criteria...........................................................................530
5.5 Buckling Strength.........................................................................530

APPENDIX 5b Bulk Carriers in Flooded Conditions – Corrugated Transverse

Watertight Bulkheads......................................................................... 531
1 Corrugated Transverse Watertight Bulkheads................................531
1.1 Application ...................................................................................531
1.3 Definitions....................................................................................531
1.5 Net Thickness and Nominal Design Corrosion Value ..................531
3 Load Model .....................................................................................531
3.1 General........................................................................................531
3.3 Minimum Bulkhead Loading ........................................................531
3.5 Flooding Head .............................................................................532
3.7 Cargo Pressure in the Intact Holds ..............................................532
3.9 Combined Cargo/Flooding Pressure in the Flooded Holds..........533
3.11 Resultant Pressure and Force .....................................................534
5 Bending Moment and Shear Force.................................................536
5.1 Bending Moment..........................................................................536
5.3 Shear Force .................................................................................536

296 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
 7 Strength Criteria..............................................................................537
7.1 General........................................................................................ 537
7.3 Bending Capacity ........................................................................ 537
7.5 Effective Shedder Plates ............................................................. 538
7.7 Effective Gusset Plates ............................................................... 538
9 Section Properties...........................................................................540
9.1 Section Modulus at the Lower End of Corrugations .................... 540
9.3 Section Modulus of Corrugations at Cross-Sections other
than the Lower End ..................................................................... 540
9.5 Effective Width of the Compression Flange................................. 541
11 Shear Strength................................................................................541
11.1 Shear Stress................................................................................ 541
11.3 Shear Buckling ............................................................................ 541
13 Local Net Plate Thickness ..............................................................541
15 Stool Construction...........................................................................542
17 Local Scantlings and Details...........................................................542
17.1 Shedder Plates............................................................................ 542
17.3 Gusset Plates .............................................................................. 542

FIGURE 1.....................................................................................................533
FIGURE 2.....................................................................................................535
FIGURE 3.....................................................................................................536
FIGURE 4 Symmetric Shedder Plates ...................................................539
FIGURE 5 Asymmetric Shedder Plates..................................................539
FIGURE 6 Symmetric Gusset/Shedder Plates .......................................539

APPENDIX 5c Bulk Carriers in Flooded Conditions – Permissible Cargo

Loads in Holds ................................................................................... 543
1 Permissible Cargo Loads in Holds..................................................543
1.1 Application................................................................................... 543
1.3 Net Thickness and Nominal Design Corrosion Value.................. 543
1.5 Check of Proposed Loading Conditions ...................................... 543
3 Load Model .....................................................................................543
3.1 General........................................................................................ 543
3.3 Flooding Head ............................................................................. 543
3.5 External Sea Water Head............................................................ 544
5 Shear Strength and Shear Capacity ...............................................544
5.1 Floor Shear Strength ................................................................... 544
5.3 Girder Shear Strength ................................................................. 546
5.5 Shear Capacity of Double Bottom ............................................... 546
7 Allowable Cargo Load in Holds.......................................................546

FIGURE 1.....................................................................................................544
FIGURE 2.....................................................................................................545
FIGURE 3.....................................................................................................548

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 297
 APPENDIX 6 Harmonized System of Notations and Corresponding Design
Loading Conditions for Bulk Carriers............................................... 549
1 General ...........................................................................................549
3 Application.......................................................................................549
5 Harmonized Notations ....................................................................550
5.1 Mandatory Notations and Notes ..................................................550
5.3 Additional Notations.....................................................................550
7 Design Loading Conditions for Harmonized Notations...................550
7.1 General Loading Conditions ........................................................550
7.3 Local Loading Conditions for Each Individual Hold......................553

TABLE 1 Application of 5C-3-A6/7.1 ....................................................553

TABLE 2A Cargo Hold Loads (5C-3-A6/7.3) – Single Hold....................557
TABLE 2B Cargo Hold Loads (5C-3-A6/7.3)
(loads in each hold shown) ...................................................557

APPENDIX 7 Guide for Hull Girder Ultimate Strength Assessment of Bulk

Carriers................................................................................................ 558
1 General ...........................................................................................558
3 Vertical Hull Girder Ultimate Limit State .........................................558
5 Hull Girder Ultimate Bending Moment Capacity .............................559
5.1 General........................................................................................559
5.3 Physical Parameters....................................................................560
5.5 Calculation Procedure .................................................................561
5.7 Assumptions and Modeling of the Hull Girder Cross-section.......562
5.9 Stress-strain Curves σ-ε (or Load-end Shortening Curves) .........564

FIGURE 1 Bending Moment – Curvature Curve M-κ .............................559

FIGURE 2 Dimensions and Properties of Stiffeners ..............................561
FIGURE 3 Example of Defining Structural Elements .............................563
FIGURE 4 Example of Stress Strain Curves σ-ε ....................................564

298 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
PART Section 1: Introduction

5C
CHAPTER 3 Vessels Intended to Carry Ore or Bulk Cargoes
(150 meters (492 feet) or more in Length)

SECTION 1 Introduction

1 General

1.1 Classification (1 July 2003)

In accordance with 1-1-3/3 and 1-1-3/25, the classification notations À A1 Bulk Carrier, BC-A, (or
BC-B or BC-C), SH, SHCM; À A1 Ore Carrier, SH, SHCM; À A1 Ore or Oil Carrier, SH, SHCM;
or À A1 Oil or Bulk/Ore (OBO) Carrier, SH, SHCM are to be assigned, as applicable, to vessels designed
for the carriage of bulk cargoes, or ore cargoes, and built to the requirements of this Chapter and other
relevant Parts/Chapters of the Rules. The bulk carrier notation BC-A or BC-B denotes that a vessel has
been designed for the carriage of dry bulk cargoes of cargo density of 1.0 tonne/m3 (62.4 lbs/ft3) and above
and may or may not have special loading arrangements. Where a BC-A or BC-B bulk carrier is not designed
to carry 3.0 tonnes/m3 (187 lbs/ft3) or higher density cargoes, it will be distinguished by the maximum
cargo density in tonnes/m3 following the bulk carrier notation, e.g., BC-B (maximum cargo density:
1.90 tonnes/m3). A BC-A bulk carrier designed to carry heavy cargo with specified holds empty will be
distinguished by a supplementary note, “(holds, x, y,… may be empty)” followed by (maximum cargo
density: ρ tonnes/m3), e.g., BC-A (holds 2, 4, 6 and 8 may be empty with maximum cargo
density: 2.50 tonnes/m3). The bulk carrier notation BC-C denotes that a vessel has been designed for
the carriage of cargo density of less than 1.0 tonne/m3 (62.4 lbs/ft3). Additionally, the above bulk carrier
notations will be followed by the (no MP) notation where a bulk carrier has not been designed for loading
and unloading in multiple ports, e.g., BC-B (maximum cargo density: 1.70 tonnes/m3)(no MP).
Full particulars of the loading conditions and the maximum density of the cargoes to be carried are to be
identified on the basic design drawings.

1.2 Optional Class Notation for Design Fatigue Life (2003)

Vessels designed and built to the requirements in this Chapter are intended to have a structural fatigue life
of not less than 20 years. Where a vessel’s design calls for a fatigue life in excess of the minimum design
fatigue life of 20 years, the optional class notation FL (year) will be assigned at the request of the
applicant. This optional notation is eligible, provided the excess design fatigue life is verified to be in
compliance with the criteria in Appendix 1 of this Chapter, “Guide for Fatigue Strength Assessment of
Bulk Carriers.” Only one design fatigue life value is published for the entire structural system. Where
differing design fatigue life values are intended for different structural elements within the vessel, the
(year) refers to the least of the varying target lives. The ‘design fatigue life’ refers to the target value set
by the applicant, not the value calculated in the analysis.
The notation FL (year) denotes that the design fatigue life assessed according to Appendix 1 of this
Chapter is greater than the minimum design fatigue life of 20 years. The (year) refers to the fatigue life
equal to 25 years or more (in 5-year increments) as specified by the applicant. The fatigue life will be
identified in the Record by the notation FL (year); e.g., FL(30) if the minimum design fatigue life
assessed is 30 years.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 299
Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 1 Introduction 5C-3-1

1.3 Application (1996)

1.3.1 Size and Proportions
The requirements contained in this Chapter are applicable to vessels of 150 meters (492 feet) or
more in length, having proportions within the range specified in 3-2-1/1, and are intended for
unrestricted service.
1.3.2 Vessel Types
The equations and formulae for determining design load and strength requirements, as specified in
5C-3-3 and 5C-3-4, are applicable to double hull or single hull bulk carriers and also to ore or
ore/oil carriers with modifications and additions as specified in Appendix 5C-3-A3. In general, the
strength assessment procedure and failure criteria as specified in Section 5C-3-5 are applicable to
all types of bulk carriers.
1.3.3 Direct Calculations
Direct calculations with respect to the determination of design loads and the establishment of
alternative strength criteria based on first principles will be accepted for consideration, provided
that all supporting data, analysis procedures and calculated results are fully documented and submitted
for review. In this regard, due consideration is to be given to the environmental conditions,
probability of occurrence, uncertainties in load and response predictions, and reliability of the
structure in service. For long term prediction of wave loads, realistic wave spectra covering the
North Atlantic Ocean and a probability level of 10-8 are to be employed.
1.3.4 SafeHull Construction Monitoring Program (1 July 2001)
For the class notation SH, SHCM, a Construction Monitoring Plan for critical areas, prepared in
accordance with the requirements of Part 5C, Appendix 1, is to be submitted for approval, prior to
comencement of fabrication. See Part 5C, Appendix 1 “Guide for SafeHull Construction Monitoring
Program.”
1.3.5 Additional Design Loading Conditions for Bulk Carrier Notation, BC-A, BC-B or BC-C
(1 July 2003)
The corresponding design loading conditions in respect to strength and stability for a harmonized
system of bulk carrier notations, BC-A, BC-B or BC-C, are to comply with the requirements of
Appendix 5C-3-A6.
1.3.6 Selection of Material Grade (1 July 2009)
Steel materials for particular locations are not to be of lower grades than those required by
3-1-2/Table 1 for the material class given in 3-1-2/Table 2, except the special application for
single-side skin bulk carriers subject to SOLAS regulation XII/6.5.3 as indicated in 5C-3-1/Table 1.

TABLE 1
Minimum Material Grades for Single-side Skin Bulk Carriers
Subject to SOLAS Regulation XII/6.5.3 (1 July 2009)
Line No. Structural Members Material Grade
BC1 Lower bracket of ordinary side frame (1, 2)
Side shell strakes included totally or partially between the two D/DH
BC2 points located to 0.125l above and below the intersection of side
shell and bilge hopper sloping plate or inner bottom plate (2)
Notes:
1 “Lower bracket” means webs of lower brackets and webs of the lower part of side
frames up to the point of 0.125l above the intersection of side shell and bilge hopper
sloping plate or inner bottom plate.
2 The span of the side frame, l, is defined as the distance between the supporting structures.

300 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 1 Introduction 5C-3-1

1.5 Definitions (2001)

1.5.1 Bulk Carrier (1 July 2003)
The class notation Bulk Carrier indicates a sea going self-propelled single deck vessel with a
double bottom and lower and upper wing tanks (hopper and topside tanks) intended for carriage of
dry cargoes in bulk. Typical midship sections are shown in 5C-3-1/Figure 1. The bulk carrier
notations as introduced in 5C-3-1/1.1 are as follows:
BC-A: Bulk carriers designed to carry dry bulk cargoes of cargo density 1.0 tonne/m3 (62.4 lbs/ft3)
and above with specified holds empty in addition to BC-B conditions.
BC-B: Bulk carriers designed to carry dry bulk cargoes of cargo density 1.0 tonne/m3 (62.4 lbs/ft3)
and above with all cargo holds loaded in addition to BC-C conditions.
BC-C: Bulk carriers designed to carry dry bulk cargoes of cargo density less than 1.0 tonne/m3
(62.4 lbs/ft3).
1.5.1(a) Double Side Skin Construction is the construction of a hold in which both sides of the
hold are bounded by two watertight boundaries, one of which is the side shell, which are not less
than 1000 mm (39.4 in.) apart measured perpendicular from the outer surface of the inner
watertight boundary to the inner surface of the side shell. This structural configuration will be
identified in column 5 of the Record with the abbreviation “DS”.
1.5.1(b) Double Side Skin Bulk Carrier is a bulk carrier with all cargo holds of double side skin
construction.
Where the Rules refer to Single Side Skin Bulk Carrier, the following interpretations apply to
vessel’s keel laid or at a similar stage of construction on or after 1 January 2000.
1.5.1(c) Single Side Skin Construction is the construction of a hold in which one or both sides of
the hold are bounded by the side shell only, or by two watertight boundaries, one of which is the
side shell, which are less than 1000 mm (39.4 in.) apart measured perpendicular from the outer
surface of the inner watertight boundary to the inner surface of the side shell.
1.5.1(d) Single Side Skin Bulk Carrier is a bulk carrier with one or more cargo holds of single
side skin construction.
1.5.2 Ore Carrier
The class notation Ore Carrier indicates a seagoing self-propelled vessel having two longitudinal
bulkheads and a double bottom throughout the cargo region intended for the carriage of ore
cargoes in the center holds only. A typical midship section is shown in 5C-3-1/Figure 2.
1.5.3 Ore or Oil Carrier
The class notation Ore or Oil Carrier indicates a seagoing self-propelled single deck vessel
having two longitudinal bulkheads and a double bottom throughout the cargo region intended for
the carriage of ore cargoes in the center holds, or for the carriage of oil cargoes in the center holds
and wing tanks. Typical midship sections are shown in 5C-3-1/Figure 4.
1.5.4 Oil or Bulk/Ore (OBO) Carrier
The class notation Oil or Bulk/Ore (OBO) Carrier indicates a seagoing self-propelled single
deck vessel of double skin construction with a double bottom and lower and upper wing tanks
(hopper and topside tanks) intended for carriage of oil or dry cargoes including ore in bulk. A
typical midship section is shown in 5C-3-1/Figure 3.

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Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 1 Introduction 5C-3-1

FIGURE 1 (1998)

FIGURE 2 (1998) FIGURE 3 (1998)

FIGURE 4 (1998)

1.5.5 Combination Carrier

A general term applied to vessels intended for carriage of either oil or dry cargoes in bulk; these
cargoes are not carried simultaneously, with the exception of oil retained in the slop tanks. Vessels
described in 5C-3-1/1.5.3 and 5C-3-1/1.5.4 are examples of Combination Carriers.

1.7 Section Properties of Structural Members (1 July 2008)

The geometric properties of structural members may be calculated directly from the dimensions of the
section and the associated effective plating (see 3-1-2/13.3 or 5C-3-4/Figure 4, as applicable). For structural
members with angle θ (see 5C-3-1/Figure 5) between web and associated plating not less than 75 degrees,
the section modulus, web sectional area and moment of inertia of the “standard” (θ = 90 degrees) section
may be used without modification. Where the angle θ is less than 75 degrees, the sectional properties are to
be directly calculated about an axis parallel to the associated plating. (see 5C-3-1/Figure 5).

302 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 1 Introduction 5C-3-1

FIGURE 5

dw

θ = 90°

Standard

dw

For longitudinals, frames and stiffeners, the section modulus may be obtained from the following equation:
SM = αθSM90
where
αθ = 1.45 − 40.5/θ

SM90 = the section modulus at θ = 90 degrees

The effective section area may be obtained from the following equation:
A = A90 sin θ
where
A90 = effective shear area at θ = 90 degrees

1.9 Protection of Structure

For the protection of structure, see 3-2-18/5

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Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 1 Introduction 5C-3-1

3 Arrangement

3.1 General
Watertight and strength bulkheads in accordance with Section 3-2-9 are to be provided. Where this is
impracticable, the transverse strength and stiffness of the hull is to be effectively maintained by deep webs
or partial bulkheads. Where it is intended to carry liquid in any of the spaces, additional bulkheads or
swash bulkheads may be required. Tank bulkheads are to be in accordance with the requirements of Part
5C, Chapter 1. The depth of double bottom at the centerline is not to be less than the height for center
girder, as obtained from Section 3-2-4. Tanks forward of the collision bulkhead are not to be arranged for
the carriage of oil or other liquid substances that are flammable.

3.3 Subdivision and Damage Stability (1 July 1998)

Single side skin bulk carriers of 150 m (492 ft) in length (Lf) and above, intended to carry solid bulk
cargoes having a density of 1.0 t/m3 (62.4 lb/ft3) or more, are to be able to withstand flooding for compliance
with Appendix 3-3-A2, “Subdivision and Damage Stability Requirements for Bulk Carriers”. (See 3-3-1/3.3
and Appendix 3-3-A2.). The review procedures for the information and calculations are to be in accordance
with 3-3-1/5.

3.5 Special Requirements for Deep Loading

Bulk carriers or ore carriers having freeboards assigned based on the subdivision requirements of the
International Convention on Load Lines, 1966, are to comply with those regulations.

5 Carriage of Oil Cargoes

5.1 General
Ore carriers and bulk carriers, which are also intended to carry oil cargoes as defined in Section 5C-1-1,
are to comply with the applicable Sections of Part 5C, Chapter 1, and Part 5C, Chapter 2, in addition to the
requirements of this Chapter.

5.3 Gas Freeing

Prior to and during the handling of bulk or ore cargoes, all spaces are to be free of cargo oil vapors.

5.5 Slop Tanks

Slop tanks are to be separated from spaces that may contain sources of vapor ignition by adequately vented
oiltight cofferdams, as defined in 5C-1-1/5.5, or by cargo oil tanks which are maintained gas free.

7 Forecastle (2004)

7.1 General
These requirements apply to all bulk carriers, ore carriers and combination carriers. These vessels are to be
fitted with an enclosed forecastle on the freeboard deck, in accordance with the requirements in this section.

7.3 Arrangements (2007)

The forecastle is to be located on the freeboard deck with its aft bulkhead fitted in way or aft of the
forward bulkhead of the foremost hold, as shown in 5C-3-1/Figure 6. However, if this requirement hinders
hatch cover operation, the aft bulkhead of the forecastle may be fitted forward of the forward bulkhead of
the foremost cargo hold provided the forecastle length is not less than 0.07Lf (Lf: see 3-1-1/3.3) abaft the
forward perpendicular.
A breakwater is not to be fitted on the forecastle deck with the purpose of protecting the hatch coaming or
hatch covers. If fitted for other purposes, it is to be located such that its upper edge at center line is not less
than HB /tan 20° forward of the aft edge of the forecastle deck, where HB is the height of the breakwater
above the forecastle (see 5C-3-1/Figure 6).

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Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 1 Introduction 5C-3-1

7.5 Dimensions
7.5.1 Heights
The forecastle height, HF, above the main deck at side is to be not less than:
• the standard height of a superstructure as specified in the International Convention on Load
Lines 1966 and its Protocol of 1988, or
• HC + 0.5 m, where HC is the height of the forward transverse hatch coaming of cargo hold No. 1,
whichever is the greater.
7.5.2 Location of Aft Edge of Forecastle Deck
All points of the aft edge of the forecastle deck are to be located at a distance lF:

l F ≤ 5 H F − HC

from the No.1 hatch forward coaming plate in order to apply the reduced loading to the No. 1
forward transverse hatch coaming and No. 1 hatch cover in applying 5C-3-4/19.

7.7 Structural Arrangements and Scantlings

The structural arrangements and scantlings of the forecastle are to comply with the applicable requirements
of 3-2-2/5.7, 3-2-5/5, 3-2-7/3, 3-2-11/1.3 and 3-2-11/9.

FIGURE 6
HB
Top of the hatch coaming

HF
HC

lF

Forward
bulkhead

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 305
PART Section 2: Design Considerations and General Requirements

5C
CHAPTER 3 Vessels Intended to Carry Ore or Bulk Cargoes
(150 meters (492 feet) or more in Length)

SECTION 2 Design Considerations and General Requirements

1 General Requirements (1996)

1.1 General (1 July 1998)

The strength requirements specified in this Chapter are based on a “net” ship approach. In determining the
required scantlings, and performing structural analyses and strength assessments, the nominal design
corrosion values given in 5C-3-2/Table 1 are to be deducted, except for the application of 5C-3-4/19 and
Appendices 5C-3-A5a, 5C-3-A5b and 5C-3-A5c, where the corrosion additions are specified within the
Section and Appendices themselves.

1.3 Initial Scantling Requirements (1996)

The initial plating thicknesses, section moduli of longitudinals/stiffeners and the scantlings of the main
supporting structures are to be determined in accordance with Section 5C-3-4 for the “net”ship for further
assessment as required in the following subsection. The relevant nominal design corrosion values are then
added to obtain the full scantling requirements.

1.5 Strength Assessment – Failure Modes (1996)

A total assessment of the structures determined on the basis of the initial strength criteria in Section 5C-3-4
is to be carried out against the following three failure modes.
1.5.1 Material Yielding
The calculated stress intensities are not to be greater than the yielding state limit given in 5C-3-5/3
for all load cases specified in 5C-3-3/9.
1.5.2 Buckling and Ultimate Strength
For each individual member, plate or stiffened panel, the buckling and ultimate strength are to be
in compliance with the requirements specified in 5C-3-5/5. In addition, the hull-girder ultimate
strength is to be in accordance with 5C-3-5/5.13.
1.5.3 Fatigue
The fatigue strength of structural details and welded joints in highly stressed regions is to be in
accordance with 5C-3-5/7.

1.7 Structural Redundancy and Residual Strength (1996)

In the early design stages, consideration should be given to structural redundancy and hull-girder residual
strength.
Vessels which have been built in accordance with the procedures and criteria for calculating and evaluating
the residual strength of hull structures in the ABS Guide for Assessing Hull-Girder Residual Strength, in
addition to other requirements of these Rules, will be classed and distinguished in the Record by the
symbol RES placed after the appropriate hull classification notation.

306 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 2 Design Considerations and General requirements 5C-3-2

1.9 Strength Assessment in the Flooded Condition (1 July 1998)

For single or double side skin bulk carriers intended to carry solid bulk cargoes having a density of 1.0 t/m3
(62.4 lb/ft3) or greater, assessments are to be carried out on the structural adequacy of the following items
in the flooded condition, in accordance with Appendices 5C-3-A5a, 5C-3-A5b and 5C-3-A5c:
i) Longitudinal Strength of the Hull Girder
ii) Water Tight Corrugated Transverse Bulkheads in Dry Cargo Holds
iii) Double Bottom Floors and Girders in Cargo Holds

3 Nominal Design Corrosion Values (NDCV) (1996)

3.1 General
As indicated in 5C-3-2/1.1, the strength criteria specified in this Chapter are based on a “net” ship approach,
wherein the nominal design corrosion values are deducted.
The “net” thickness or scantlings correspond to the minimum strength requirements acceptable for
classification, regardless of the design service life of the vessel. In addition to the coating protection specified
in the Rules, minimum corrosion values for plating and structural members as given in 5C-3-2/Table 1 and
5C-3-2/Figure 1 are to be applied. These minimum corrosion values are being introduced solely for the
above purpose, and are not to be construed as renewal standards.
In view of the anticipated higher corrosion rates for structural members in some regions, such as highly
stressed areas, it is advisable to consider additional design margins for the primary and critical structural
members in order to minimize repairs and maintenance costs. The beneficial effects of these design
margins on reduction of stresses and increase of the effective hull-girder section modulus can be
appropriately accounted for in the design evaluation.

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Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 2 Design Considerations and General requirements 5C-3-2

FIGURE 1
Nominal Design Corrosion Values (NDCV) (1996)
1.50MM
MM HEAD:
EB): 2.00 00MM G BULK
ALS (W SLOPIN
ITUDIN NGE): 1. UPPER
SH EL L LONG UDINALS (FLA
SIDE NGIT G: 1.00
MM
ELL LO COAMIN
SIDE SH
HATCH
SES HATCH EN
NSVER
ND TRA: 1.50MM D BEAM
AMES A K S: 1.50M
WEB FRER WING TAN M
IN U PP

00MM MAIN DE
NALS: 2. CK: 1.50M
NGITUDI (WITHIN M
DECK LO TCHES) LINE OF
E OF HA HATCHE
SIDE LIN S)
M (OUT
N DEC K: 2.00M E
MAI GUNWAL CROSS DE
RADIUSED CK SUPP
ORTING
STRUCTUR
2.00MM E: 1.50MM

UPPER
DRY H STOOL PL
BALLA OLD: 1. ATING
ST HO 00MM
(UPPER TURN OF BILGE

LD: 1.
TO 1.5M BELOW DECK)

50MM
SIDE SHELL: 1.50MM

50MM
TE: 3.
EB PLA
ER END W 1. 50MM TRAN
ES LO W HER E DRY SVERSE
FRAM ELSEW BALL HOLD: 1.0BULKHE
HOLD AST H 0 AD
OLD:MM
1.50M
M

LOW
DR ER ST
BALY HOLD OOL PL
M LAS : 1.00 ATIN
2.00M T HO MM G
ATE: LD:
G PL 1.50M
LOPIN M
ER S
LOW

M
ON 1.50M
ALS EADS: M
UDIN KH 2.00M
GIT
LONOPING B
U L ING:
LAT
SL TTOM P
R BO
INNE

0MM
: 1.0
ING
P LAT
TOM
BOT

WE D.B
BF . TA
IN RA NK
LO ME INT
WE S ER
R W AND NA
ING TR LS:
TA AN 2.0
NK S V 0M
: 1.5 ERSE M
0M S
M

308 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 2 Design Considerations and General requirements 5C-3-2

TABLE 1
Nominal Design Corrosion Values (NDCV) for Bulk Carriers (2002) (1, 2)
Group Structural Item NDCV in mm (in.)
1. Outer Skin a. Bottom Shell Plating (including keel and bilge plating) 1.0 (0.04)
b1. Side Shell Plating (above upper turn of bilge to 1.5 m (5 ft) below deck) 1.5 (0.06)
b2. Side Shell Plating (within 1.5 m (5 ft) from deck) 2.0 (0.08)
c. Upper Deck Plating (outside the lines of opening) 2.0 (0.08) (3)
d. Upper Deck Plating (within the lines of opening) 1.5 (0.06)
2. Double Bottom a. Inner Bottom Plating 2.0 (0.08)
b. Inner Bottom Longitudinals 2.0 (0.08) (7)
c. Floors and Girders 2.0 (0.08) (7)
d1. Miscellaneous Internal Members (in Tank) 2.0 (0.08) (7)
d2. Miscellaneous Internal Members, including CL Girder (in Dry Ducts) 1.5 (0.06)
3. Lower Wing Tank a. Top (Sloping Bulkhead) Plating 2.0 (0.08)
b. Transverses 1.5 (0.06)
c. Bottom and Bilge Longitudinals 2.0 (0.08) (7)
d1. Side longitudinals (Web) 2.0 (0.08) (7)
d2. Side Longitudinals (Flange) 1.0 (0.04)
e. Top (Sloping Bulkhead) Longitudinals 1.5 (0.06)
4. Upper Wing Tank a. Bottom (Sloping Bulkhead) Plating 1.5 (0.06) (4)
b. Inboard (Vertical) Bulkhead Plating 2.0 (0.08)
c. Transverses 1.5 (0.06) (4)
d. Deck Longitudinals 2.0 (0.08) (5)
e1. Side and Diaphragm Longitudinals (Web) 2.0 (0.08)
e2. Side and Diaphragm Longitudinals (Flange) 1.0 (0.04) (4)
f1. Bottom (Sloping Bulkhead) Longitudinals (in Tank) 1.5 (0.06) (4)
f2. Bottom (Sloping Bulkhead) Longitudinals (in Dry Hold) 1.0 (1.14)
g. Diaphragm Plating 1.5 (0.06) (4)
5. Side Frame a. Side Shell Frames in Hold 1.5 (0.06) (6)
b. Web Plates of Lower Bracket or Web Plates of Lower End of Built-Up Frames 3.5 (0.14) (6)
c. Face Plates of Lower Bracket or Web Plates of Lower End of Built-Up Frames 1.5 (0.06) (6)
6. Double Side a. Inner Bulkhead Plating 1.5 (0.06)
b1. Diaphragm Plates and Non-tight Stringers 1.5 (0.06)
b2. Tight Stringers 2.0 (0.08)
c1. Inner Bulkhead Longitudinals (Web) 2.0 (0.08)
c2. Inner Bulkhead Longitudinals (Flange) 1.0 (0.04)
d. Inner Bulkhead Vertical Stiffeners 1.5 (0.06)
7. Transverse a1. In Hold (including Stools), Plating & Stiffeners (Dry Hold) 1.0 (0.04) (8)
Bulkheads a2. In Hold (including Stools), Plating & Stiffeners (Ballast Hold) 1.5 (0.06) (8)
b. In Upper or Lower Wing Tanks, Plating 1.5 (0.06) (4)
c. In Upper or Lower Wing Tanks, Vertical Stiffeners 1.5 (0.06)
d1. Horizontal Stiffeners (Web) 2.0 (0.08)
d2. Horizontal Stiffeners (Flange) 1.0 (0.04)
e. Internals of Upper and Lower Stool (Dry) 1.0 (0.04)
8. Cross Deck Beams, Girders and other Structures 1.5 (0.06)
9. Other Members a. Hatch Coaming 1.0 (0.04)
b. Hatch End Beams, Hatch Side Girders (outside Tank) 1.5 (0.06)
c. Internals of void spaces (outside Double Bottom) 1.0 (0.04)
Notes
1 It is recognized that corrosion depends on many factors, including coating properties, and that actual wastage rates
observed may be appreciably different from those given here.
2 Pitting and grooving are regarded as localized phenomena and are not covered in this table.
3 Includes horizontal and curved portion of round gunwale.
4 To be not less than 2.0 mm (0.08 in.) within 1.5 m (5 ft) from the deck plating.
5 May be reduced to 1.5 mm (0.06 in.) if located outside tank.
6 Including frames in ballast hold.
7 May be reduced to 1.5 mm (0.06 in.) if located inside fuel oil tank.
8 When plating forms a boundary between a hold and a void space, the plating NDCV is determined by the hold type
(dry/ballast).

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 309
PART Section 3: Load Criteria

5C
CHAPTER 3 Vessels Intended to Carry Ore or Bulk Cargoes
(150 meters (492 feet) or more in Length)

SECTION 3 Load Criteria

1 General

1.1 Load Components (1996)

In the design of the hull structure of bulk carriers, all load components with respect to the hull girder and
local structure as specified in this Chapter and Section 3-2-1 are to be taken into account. These include
static loads in still water, wave-induced motions and loads, slamming, dynamic, thermal and ice loads,
where applicable.

3 Static Loads (1996)

3.1 Still-water Bending Moments and Shear Forces (1 July 1998)

For still-water bending moment and shear force calculations for intact conditions, see 3-2-1/3.3
When a direct calculation of wave-induced loads [i.e., longitudinal bending moments and shear forces,
hydrodynamic pressures (external) and inertial forces and added pressure heads (internal)] is not anticipated,
envelope curves are to be provided for the still-water bending moments (hogging and sagging) and shear
forces (positive and negative).
Except for special loading cases, the loading patterns shown in 5C-3-3/Figure 1 are to be considered in
determining local static loads.
For alternate cargo hold loading conditions, modification for the hull girder shear forces may be applied in
accordance with 3-2-1/3.9.3.
For single or double side skin bulk carriers intended to carry solid bulk cargoes having a density of 1.0 t/m3
(62.4 lb/ft3) or greater, still-water bending moment and shear force calculations in the hold flooded condition
are to be submitted for each of the at-sea cargo and ballast loading conditions shown in the intact longitudinal
strength calculations. See Appendix 5C-3-A5a.

3.3 Bulk Cargo Pressures

The bulk cargo pressures acting on the internal surfaces of the cargo holds, in still water, may be
determined based on the equations given in 5C-3-3/5.7.2 for static cargo pressure components, Psn and Pst,
normal and parallel to the wall surface, respectively. For vessels carrying cargoes on deck, the specific
weight of the cargoes, maximum stowage height and the intended cargo distribution are to be submitted for
review and to be appropriately accounted for in the loading manual.

310 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
 Part

Section
Chapter

**

***
****
Loading Pattern of Conventional Bulk Carrier***
3 Load Criteria
5C Specific Vessel Types

LOAD CASE 1 LOAD CASE 2 LOAD CASE 3 LOAD CASE 4 LOAD CASE 5
Heading 0 Deg. Heading 0 Deg. Heading 0 Deg. Heading 0 Deg. Heading 90 Deg.
Heave Down Heave Up Heave Down Heave Up Heave Down
Pitch Bow Down Pitch Bow Up Pitch Bow Down Pitch Bow Up Pitch -
Roll - Roll - Roll - Roll - Roll STBD Down
Draft 2/3 Draft Full Draft 2/3 Draft Full Draft 2/3
Wave VBM Sag Wave VBM Hog Wave VBM Sag Wave VBM Hog Wave VBM Sag
Cargo Min S.G. 1.0/1.5 Cargo Min S.G. 1.0/1.5 Cargo Min S.G. 1.0/1.5 Cargo Min S.G. 1.0/1.5 Cargo Min S.G. 1.66/3.00
Ballast S.G. 1.025 Ballast S.G. 1.025 Ballast S.G. 1.025 Ballast S.G. 1.025 Ballast S.G. 1.025

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

vessels designed for homogeneous loading only.
FIGURE 1

LOAD CASE 6 LOAD CASE 7 LOAD CASE 8 LOAD CASE 9 LOAD CASE 10

minimum 1.5 is to be used as special block load case on ship by ship basis.
Heading 90 Deg. Heading 60 Deg. Heading 60 Deg. Heading 60 Deg. Heading 60 Deg.

(2003) For Load Cases 9 and 10, draft d = [47 – 0.11(L – 150)]L/1000 m (ft).
Heave Up Heave Down Heave Up Heave Down Heave Up
Pitch - Pitch Bow Down Pitch Bow Up Pitch Bow Down Pitch Bow Up
Roll STBD Up Roll STBD Down Roll STBD Up Roll STBD Down Roll STBD Up
Draft Full Draft 2/3 Draft Full Draft **** Draft ****
Wave VBM Hog Wave VBM Sag Wave VBM Hog Wave VBM Sag Wave VBM Hog
Loading Pattern of Conventional Bulk Carrier (2003)

Cargo Min S.G. 1.66/3.00 Cargo Min S.G.** 1.0/1.5 Cargo Min S.G. 1.0/1.5 Cargo Min S.G. - Cargo Min S.G. -
Ballast S.G. 1.025 Ballast S.G. 1.025 Ballast S.G. 1.025 Ballast S.G. 1.025 Ballast S.G. 1.025
3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or More in Length)

Ballast, Specific Gravity 1.025 Cargo, Min. Specific Gravity* 1.0/1.5 Cargo, Min. Specific Gravity* 1.66/3.00

Loading pattern may be subject to special consideration where a vessel is designed for homogeneous loading only.

311
5C-3-3

by cargo volume of each load case is to be used. The specific gravity is not to be taken as less than the higher value

for those designed for heavy cargo. The lower value of two minimum specific gravities is applicable to all other

All vessels are to be checked for the lower specific gravity with minimum 1.0. The higher specific gravity with
of two minimum specific gravities for all vessels designed for alternate hold loading with certain holds empty and
The maximum value of cargo specific gravity (relative density) calculated as the maximum cargo weight divided
Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or More in Length)
Section 3 Load Criteria 5C-3-3

5 Wave-Induced Loads

5.1 General (1996)

Where a direct calculation of the wave-induced loads is not available, the approximation equations given
below and specified in 3-2-1/3.5 may be used to calculate the design loads.
When a direct calculation is performed, envelope curves for the combined wave and still-water bending
moments and shear forces covering all the anticipated loading conditions are to be submitted for review.

5.3 Additional Wave Induced Moments and Shear Force (1996)

5.3.1 Horizontal Wave Bending Moment
The horizontal wave bending moment, expressed in kN-m (tf-m, Ltf-ft), positive (tension port) or
negative (tension starboard), may be obtained from the following equation:
MH = ± mhK3C1L2DCb × 10-3
where
mh = distribution factor, as given by 5C-3-3/Figure 2
K3 = 180 (18.34, 1.68)
C1 and Cb are as given in 3-2-1/3.5.
L = length of vessel, as defined in 3-1-1/3.1, in m (ft)
D = depth of vessel, as defined in 3-1-1/7.3, in m (ft)
5.3.2 Horizontal Wave Shear Force
The envelope of horizontal wave shearing force, FH, expressed in kN (tf, Ltf), positive (toward
port forward) or negative (toward starboard aft), may be obtained from the following equation:
FH = ± fh k C1LD(Cb + 0.7) × 10-2
where
fh = distribution factor as given in 5C-3-3/Figure 3
k = 36 (3.67, 0.34)
C1 and Cb are as defined in 3-2-1/3.5.
L = length of vessel, as defined in 3-1-1/3.1, in m (ft)
D = depth of vessel, as defined in 3-1-1/7.3, in m (ft)
5.3.3 Torsional Moment
5.3.3(a) Nominal Torsional Moment. The nominal torsional moment amidships, in kN-m (tf-m,
Ltf-ft), positive clockwise looking forward, may be determined as follows:
TM = kLB2d1[(Cw − 0.5)2 + 0.1][0.13 − (e/D)(co/d1)1/2]
where
k = 2.7 (0.276, 0.077)
co = 0.14 (0.14, 0.459)
d1 = draft, as defined in 3-1-1/9, but not less than 12.5 m (41 ft)

312 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or More in Length)
Section 3 Load Criteria 5C-3-3

e = the vertical distance, in m (ft), of the effective shear center of the hull girder
within cargo space, measured from the baseline of the vessel, positive upward.
For simplification, the effective shear center of a typical cargo hold may be
estimated by considering a closed cargo hold, of which the original hatch
opening is considered to be closed by a thin plate of equivalent thickness.
This thin plate should be made up by “stretching” lengthwise the cross deck
plating and, if applicable, the upwardly projected upper box stool plating at
vessel centerline between hatch openings to cover the whole length of the
cargo hold. This plate’s volume should be equivalent to the original plate
volume of the cross deck plating plus, if applicable, that of the projected
upper box stool plating.
Cw = waterplane coefficient for the scantling draft, if not available, it may be
approximated by 1.09 Cb. Cw, but need not be taken greater than 0.98 for
typical bulk carriers.
Cb is as defined in 3-2-1/3.5.
L = length of vessel, as defined in 3-1-1/3.1, in m (ft)
B = breadth of vessel, as defined in 3-1-1/5, in m (ft)
D = depth of vessel, as defined in 3-1-1/7.3, in m (ft)
5.3.3(b) Distribution of Torsional Moment. The nominal torsional moment along the length of
the vessel L may be obtained by multiplying the midship value by the distribution factor mT given
by 5C-3-3/Figure 6.

5.5 External Pressures (1996)

5.5.1 Pressure Distribution
The external pressures, Pe, positive toward inboard, imposed on the hull in seaways can be expressed
by the following equation at a given location.
pe = ρ g (hs + kuhde ) ≥ 0 in N/cm2 (kgf/cm2, lbf/in2)
where
ρg = specific weight of sea water
= 1.005 N/cm2-m (0.1025 kgf/cm2-m, 0.4444 lbf/in2-ft)
hs = hydrostatic pressure head in still water, in m (ft)
ku = load factor, and may be taken as unity unless otherwise specified.
hde = hydrodynamic pressure head induced by the wave, in m (ft), may be
calculated as follows:
hde = kchdi
where
kc = correlation factor for a specific combined load case, as given in 5C-3-3/7 and
5C-3-3/9
hdi = hydrodynamic pressure head, in m (ft), at location i, (i = 1, 2, 3, 4 or 5; see
5C-3-3/Figure 4 )
= klαihdo in m (ft)
kl = distribution factor along the length of the vessel
= 1 + (klo − 1) cos μ, klo is as given in 5C-3-3/Figure 5
hdo = 1.36 kC1 in m (ft)

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C1 = as defined in 3-2-1/3.5
k = 1 (1, 3.281)
αi = distribution factor around the girth of vessel at location i. Intermediate
location may be obtained by linear interpolation.
= 1.00 − 0.25 cos μ, for i = 1, at WL, starboard
= 0.40 − 0.10 cos μ, for i = 2, at bilge, starboard
= 0.30 − 0.20 sin μ, for i = 3, at bottom centerline
= 2α3 − α2, for i = 4, at bilge, port
= 0.75 − 1.25 sin μ, for i = 5, at WL, port
μ = wave heading angle to be taken from 0° to 90° (0° for head sea, 90° for beam
sea for wave coming from starboard)
The distribution of the total external pressure, including static and hydrodynamic pressure, is illustrated
in 5C-3-3/Figure 14.
5.5.2 Extreme Pressures
In determining the required scantlings of local structural members, the extreme external pressure,
pe, as defined in 5C-3-3-/5.5.1 with ku given in 5C-3-3/7 and 5C-3-3/9 is to be used.

5.5.3 Simultaneous Pressures

For performing 3D structural analysis, the simultaneous pressure along any portion of the hull
girder may be obtained from:
pes = ρ g (hs + kf kuhde ) ≥ 0 in N/cm2 (kgf/cm2, lbf/in2)
where
kf is the distribution function of hde, corresponding to a designated wave profile along the vessel’s
length, and may be determined as follows:
5.5.3(a) For the combined load cases, L.C.1 through L.C.6 specified in 5C-3-3/Table 1
kf = kfo {1 − [1 − cos 2π (x/L − xo /L)] cos μ}
5.5.3(b) For the combined load cases, L.C.7 and L.C.8 specified in 5C-3-3/Table 1
kf = kfo cos{4π (x/L − xo /L − 0.25) cos μ}
5.5.3(c) For the combined load cases, L.C.9 and L.C.10 specified in 5C-3-3/Table 1
kf = kfo cos{4π (x/L − xo /L) cos μ}
where
x = distance from A.P. to the station considered, in m (ft)
xo = distance from A.P. to the reference station, in m (ft)
The reference station is the point along the vessel’s length where the wave
trough or crest is located in head seas and may be taken as the mid-point of
the mid-hold of the three hold model.
L = the vessel length, as defined in 3-1-1/3.1, in m (ft)
μ = the wave heading angle, to be taken from 0° to 90°
kfo = ±1.0, as specified in 5C-3-3/Table 1
The simultaneous pressure distribution around the girth of the vessel is to be determined based on
the wave heading angles specified in 5C-3-3/Table 1.

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5.5.4 Impact Loads on Bow and Deck

5.5.4(a) Bow Pressures. When experimental data or direct calculation are not available, nominal
wave-induced bow pressures above LWL in the region from the forward end to the collision
bulkhead may be obtained from the following equation:

pbij = kCkCij Vij2 sin γij kN/m2 (tf/m2, Ltf/ft2)

where
k = 1.025 (0.1045, 0.000888)
Cij = {1 + cos2 [90(Fbi − 2aij)/Fbi]}1/2
Vij = ω1V sin αij + ω2(L)1/2
ω1 = 0.515 (0.515, 1.68)
ω2 = 1.0 (1.0, 1.8)
V = 75% of the design speed, Vd, in knots. V is not to be taken less than 10
knots. Vd is defined in 3-2-14/3.
γij = local bow angle measured from the horizontal, not to be taken less than 50°
= tan-1 (tan βij/cos αij)
αij = local waterline angle measured from the centerline, see 5C-3-3/Figure 7, not
to be taken less than 35°
βij = local body plan angle measure from the horizontal, see 5C-3-3/Figure 7, not
to be taken less than 35°
Fbi = freeboard from the highest deck at side to the load waterline (LWL) at station
i, see 5C-3-3/Figure 7
aij = vertical distance from the LWL to WLj, see 5C-3-3/Figure 7
Ck = 0.7 at collision bulkhead and 0.9 at 0.0125L, linear interpolation for in
between
= 0.9 between 0.0125L and the FP
= 1.0 at and forward of the FP
i, j = station and waterline, to be taken to correspond to the locations as required
by 5C-3-6/1.1
5.5.4(b) Green Water. When experimental data or direct calculation is not available, nominal
green water pressures imposed on deck in the region from the FP to 0.25L aft, including the
extension beyond the FP, may be obtained from the following equations. Pgi is not to be taken
less than 20.6 kN/m2 (2.1 tf/m2, 0.192 Ltf/ft2).
pgi = k (MRi − k1Fbi )1/2 kN/m2 (tf/m2, Ltf/ft2)
where
k = 19.614 (2.0, 0.0557)
k1 = 1.0 (1.0, 3.28)
MRi = 0.44 Ai (VL/Cb )1/2 for L in meters
= 2.615 Ai (VL/Cb )1/2 for L in feet
V = 75% of the design speed, Vd, in knots. V is not to be taken less than 10 knots.
Vd = as defined in 3-2-14/3

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Fbi = as defined in 5C-3-3/5.5.4(a)

Ai = as shown in 5C-3-3/Table 2
Cb = as defined in 3-2-1/3.5
L = length of vessel, as defined in 3-1-1/3.1, in m (ft)

5.7 Internal Pressures – Inertia Forces and Added Pressure Heads (1996)
5.7.1 Ship Motions and Accelerations
In determining cargo pressures and ballast pressures, the dominating ship motions, pitch and roll,
and the resultant accelerations induced by the wave are required. When a direct calculation is not
available, the equations given below may be used.
5.7.1(a) Pitch. (1997) The pitch amplitude: (positive bow up)
φ = k1(V/Cb)1/4/L, in deg.
but need not to be taken more than 10 deg.
The pitch natural period:

Tp = k2 C b d i in sec.

where
k1 = 1030 (3378) for L in m (ft)
k2 = 3.5 (1.932) for di in m (ft)
V = 75% of the design speed, Vd , in knots. V is not to be taken less than 10 knots.
Vd is defined in 3-2-14/3.
di = draft amidships for the relevant loading conditions
L and Cb are as defined in 3-1-1/3.1 and 3-1-1/11.3, respectively.
5.7.1(b) Roll. The roll amplitude: (positive starboard down)
θ = CR (35 − kθ Cdi Δ/1000) if Tr > 20 sec.
θ = CR (35 − kθ CdiΔ/1000)(1.5375 − 0.027Tr) if 12.5 ≤ Tr ≤ 20 sec

θ = CR (35 − kθ CdiΔ/1000)(0.8625 + 0.027Tr) if Tr ≤ 12.5 sec

kθ = 0.005 (0.05, 0.051)
θ in degrees, need not be taken more than 30 deg.
CR = 1.3 − 0.025V
Cdi = 1.06 (di /d) − 0.06
di = draft amidships for the relevant loading conditions, m (ft)
d = draft as defined in 3-1-1/9, in m (ft)
Δ = kd L B d Cb kN (tf, Ltf)
kd = 10.05 (1.025, 0.0286)
L and B are as defined in 3-1-1/3.1 and 3-1-1/5, respectively, in m (ft).

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The roll natural motion period:

Tr = k4kr /GM1/2 in sec.
where
k4 = 2 (1.104) for kr, GM in m (ft)
kr = roll radius of gyration, in m (ft), and may be taken as 0.35B for full load
conditions and 0.40B for ballast conditions.
GM = metacentric height, to be taken as:
= GM (full) for di = d
= 1.5 GM (full) for di = 2d/3
= 2.0 GM (full) for di = d/2
GM (full) = metacentric height for fully loaded condition. If GM (full) is not available,
GM (full) may be taken as 0.12B for the purpose of estimation.
5.7.1(c) Accelerations. The vertical, longitudinal and transverse accelerations of tank contents
(cargo or ballast), av, al and at may be obtained from the following formulae:
av = Cvkvaog m/sec2 (ft/sec2) positive downward
al = Clklaog m/sec2 (ft/sec2) positive forward
at = Ctktaog m/sec2 (ft/sec2) positive starboard
where
ao = ko(2.4/L1/2 + 34/L − 600/L2) for L in m
= ko(4.347/L1/2 + 111.55/L − 6458/L2) for L in ft
ko = 0.86 + 0.048V − 0.47 Cb
Cv = cos μ + (1 + 2.4 z/B) (sin μ)/kv

μ = wave heading angle in degrees, 0° for head sea, and 90° for beam sea for
wave coming from starboard
kv = [1 + 0.65(5.3 − 45/L)2(x/L − 0.45)2]1/2 for L in m

= [1 + 0.65(5.3 − 147.6/L)2(x/L − 0.45)2]1/2 for L in ft

Cl = 0.35 − 0.0005(L − 200) for L in m
= 0.35 − 0.00015(L − 656) for L in ft
kl = 0.5 + 8y/L
Ct = 1.27[1 + 1.52(x/L − 0.45)2]1/2
kt = 0.35 + y/B
L, B are the length and breadth of vessel, as defined in 3-1-1/3.1 and 3-1-1/5, respectively, in m (ft).
x = longitudinal distance from the AP to the station considered, in m (ft)
y = vertical distance from the waterline to the point considered, in m (ft),
positive upward
z = transverse distance from the centerline to the point considered, in m (ft),
positive starboard
g = acceleration of gravity = 9.8 m/sec2 (32.2 ft/sec2)

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5.7.2 Bulk Cargo Pressures

5.7.2(a) Bulk Cargo Pressures on Inner Bottom and Side Wall within 0.4L Amidships. The bulk
cargo pressures, acting on the inner bottom, side wall and sloped bottom of a cargo hold may be
expressed by pressure components, pcn, pct(t) and pct(l), in directions normal, parallel to the wall
surface in transverse direction, and parallel to the wall surface in longitudinal direction,
respectively. These components can be determined by the following equations:
pcn = psn + ku pdn N/cm2 (kgf/cm2, lbf/in2)
pct(t) = pst(t) + ku pdt(t) N/cm2 (kgf/cm2, lbf/in2)
pct(l) = pst(l) + ku pdt(l) N/cm2 (kgf/cm2, lbf/in2)
where
psn = nominal static pressure component due to gravity

= ρ g hc{cos2α + (1 − sin αo) sin2α}

pst(t) = tangential static pressure component due to gravity in transverse direction
(positive shown in 5C-3-3/Figure 8)
= ρ ghc(sin αo sin α cos α)
pst(l) = tangential static pressure component due to gravity in longitudinal direction
(positive shown in 5C-3-3/Figure 8)
= 0
pdn = dynamic pressure component due to vessel’s roll, pitch, vertical and
transverse accelerations
= kc[pqn + ρ ghc {(ave/g) cos2α + kn (ate/g) (b/2hc) sin2α}]
pqn = additional normal pressure component due to roll and pitch
= ρ gh* cos φe [cos2 (α − θe) + (1 − sin αo) sin2(α − θe)] − psn
pdt(t) = tangential dynamic pressure component due to vessel’s roll, pitch, vertical
and transverse accelerations in transverse direction (positive shown in
5C-3-3/Figure 8)
= kc [pqt(t) + ρ ghc {(ave/g) sin α cos α − kn(ate/g)(b/2hc) sin α cos α}]
pqt(t) = ρ gh* cos φe sin αo sin(α − θe) cos(α − θe) − pst(t)
pdt(l) = tangential dynamic pressure component due to vessel’s roll, pitch, vertical
and transverse accelerations in longitudinal direction (positive shown in
5C-3-3/Figure 8)
= kc[−ρ gh* cos φe sin αo cos(α − θe) sin φe]
kc = correlation coefficient and may be taken as unity unless otherwise specified
ku = dynamic load factor and may be taken as unity unless otherwise specified
where
ρg = specific weight of the bulk cargo considered, in N/cm2-m (kgf/cm2-m, lbf/in2-ft)
α = slope of wall measured from horizontal plane, in degrees (see 5C-3-3/Figure 9)
αo = angle of repose for the bulk cargo considered, normally 30 degrees
(Re: “Code of Safe Practice for Solid Bulk Cargoes” published by IMO)
θe = effective angle of roll = 0.71 Cθθ, in degrees

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φe = effective angle of pitch = 0.71 Cφφ, in degrees

hc = vertical distance from the top cargo surface to the wall point considered in
upright condition, in m (ft), as shown in 5C-3-3/Figure 10
h* = vertical distance from the top of cargo surface to the wall point considered in
heeled condition, in m (ft), as shown in 5C-3-3/Figure 10
b = width of the cargo hold at the level of the wall point considered, in m (ft)
ave = effective vertical acceleration
= 0.71 cvav, in m/sec2 (ft/sec2)
ate = effective transverse acceleration
= 0.71 cT at , in m/sec2 (ft/sec2)
cv, cT, Cθ and Cφ are as specified in 5C-3-3/Table 1.
kn = 0.33 unless otherwise specified
av and at are as specified in 5C-3-3/5.7.1(c).
If the direction of gravity is away from the wall at the point considered, the following equation can
be used:
pqn = ρ ghc cos φe [cos θe(1 − sin αo) sin2(α − θe)] − psn
pqt(t) = ρ ghc cos φe cos θe(1 − sin αo) sin(α − θe) cos(α − θe) − pst
pdt(t) = −ρ ghc sin φe cos θe(1 − sin αo) sin(α − θe) cos(α − θe)
5.7.2(b) Bulk Cargo Pressures on Transverse Bulkhead within 0.4L Amidships. The bulk cargo
pressures acting on transverse bulkheads and stools can be similarly obtained when the wall angle
is defined as β.
pcn = psn + ku pdn N/cm2 (kgf/cm2, lbf/in2)
pct(t) = pst(t) + ku pdt(t) N/cm2 (kgf/cm2, lbf/in2)
pct(l) = pst(l) + ku pdt(l) N/cm2 (kgf/cm2, lbf/in2)
where
psn = nominal static pressure component due to gravity

= ρ ghc{cos2 β + (1 − sin αo) sin2 β}

pst(t) = tangential static pressure component due to gravity in transverse direction
(positive shown in 5C-3-3/Figure 8)
= 0
pst(l) = tangential static pressure component due to gravity in longitudinal direction
(positive shown in 5C-3-3/Figure 8)
= −ρ ghc(sin αo sin β cos β)
pdn = dynamic pressure component due to vessel’s roll, pitch, vertical and
longitudinal accelerations
= kc[pqn + ρ ghc{(ave /g) cos2β + kn(ale/g)(l/2hc) sin2β}]
pqn = additional normal pressure component due to roll and pitch

= ρ gh* cos θe[cos2(β + φe) + (1 − sin αo) sin2(β + φe)] − psn

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pdt(t) = tangential dynamic pressure component due to vessel’s roll, pitch, vertical
and longitudinal accelerations in transverse direction (positive shown in
5C-3-3/Figure 8)
= kc[−ρ gh* sin αo cos(β + φe) sin θe]
pdt(l) = tangential dynamic pressure component due to vessel’s roll, pitch, vertical
and longitudinal accelerations in longitudinal direction (positive shown in
5C-3-3/Figure 8)
= kc[pqt(l) − ρ ghc{(ave /g) sin β cos β + kn(ale /g) (l/2hc) sin β cos β}]

pqt(l) = −ρ gh* sin αo sin(β + φe) cos(β + φe) − pst(l)

β = slope of wall measured from horizontal plane, in degrees, as shown in

5C-3-3/Figure 11
l = length of the cargo hold at the level of the wall point considered, in m (ft)
al e = effective longitudinal acceleration
= 0.71 cL al, m/sec2 (ft/sec2)
cv, cL, Cθ and Cφ are as specified in 5C-3-3/Table 1.
kn = 0.33 unless otherwise specified
al is as specified in 5C-3-3/5.7.1(c).
5.7.2(c) Cargo Pressure Outside of 0.4L Amidships. Where the vessel form changes significantly
outside 0.4L amidships, the cargo pressures on the side shell may be obtained based on the vector
sum of the normal and tangential components considering the orientation of the plates.
5.7.2(d) Extreme Cargo Pressure. For assessing local structures at a cargo hold boundary, the
extreme cargo pressure determined based on a specified dynamic load factor, ku (equal or greater
than unity), in 5C-3-3/7 is to be considered.
5.7.2(e) Simultaneous Cargo Pressures. In performing a 3D structural analysis, the internal cargo
pressures may be calculated in accordance with 5C-3-3/5.7.2(a), 5C-3-3/5.7.2(b) and 5C-3-3/5.7.2(c)
above for cargo holds in the midbody region. For cargo holds in the fore or aft body regions, the
pressures are to be determined based on linear distributions of acceleration and ship motions along
the length of the vessel.
5.7.3 Internal Ballast Liquid Pressures
For wing and ballast tanks, the internal liquid pressures may be determined in accordance with
5C-3-3/5.7.2 with consideration of overflows.
5.7.3(a) Distribution of Internal Pressures. The internal ballast pressures, pi, positive toward
tank boundaries for a fully filled ballast tank, may be obtained from the following formula:
pi = ρ g(η + kuhd) ≥ 0 in N/cm2 (kgf/cm2, lbf/in2)
where
ρg = specific weight of the liquid, in N/cm2-m (kgf/cm2-m, lbf/in2-ft)
η = local vertical coordinate for tank boundaries measuring, as shown in
5C-3-3/Figure 12, in m (ft)
ku = load factor and may be taken as unity unless otherwise specified
hd = wave induced pressure head, including inertial force and added pressure head
= kc(ηiai/g + Δhi), in m (ft)

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ηi = local coordinate in vertical direction for tank boundaries measuring from the
top of the tank
kc = correlation factor and may be taken as unity unless otherwise specified
ai = effective resultant acceleration, in m/sec2 (ft/sec2), at the point considered
and may be approximated by
ai = 0.71 Cdp [wvav + wl (l/h)al + wt (b/h)at]
Cdp = 1.0 for rectangular tank, upper wing tank, lower wing tank
= 0.7 for J-shaped ballast tanks of double hull type bulk carrier
av, al and at are as given in 5C-3-3/5.7.1(c).
wv, wl and wt are weighted coefficients and showing directions as specified in 5C-3-3/Table 1.
Δhi = added pressure head due to pitch and roll motions at the point considered, in
m (ft), may be calculated as follows
i) for bow down and starboard down (φe < 0, θe > 0)
Δhi = ξ sin(-φe) + (ζe sin θe cos φe + ηe cos θe cos φe − η)
for tank without overflows
Δhi = (ξ − l/2) sin(-φe) + (ζe sin θe cos φe + ηe cos θe cos φe − η)
for tank with overflows
ζe = b−ζ
ηe = η
ii) for bow up and starboard up (φe > 0, θe < 0)
Δhi = (l − ξ) sin φe + (ζe sin(-θe) cos φe + ηe cos θe cos φe − η)
for tank without overflows
Δhi = (l/2 − ξ) sin φe + (ζe sin(-θe) cos φe + ηe cos θe cos φe − η)
for tank with overflows
ζe = ζ − ζb
ηe = η − δh
ξ, ζ, η are the local coordinates, in m (ft), for the point considered with respect to the origin shown
in 5C-3-3/Figure 12.
δb and δh are the local coordinate adjustments, in m (ft), for a rounded tank corner, as shown in
5C-3-3/Figure 12.
where
θe = 0.71 Cθ θ

φe = 0.71 Cφ φ

l = length of the tank, in m (ft)

b = breadth of the tank considered, in m (ft)
h = height of the tank considered, in m (ft)
φ and θ are pitch and roll amplitude as given in 5C-3-3/5.7.1(a) and (b).
Cφ and Cθ are weighted coefficients and showing directions as given in 5C-3-3/Table 1.

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5.7.3(b) Extreme Internal Ballast Pressure. For assessing local structures at a tank boundary, the
extreme internal ballast pressure with ku as specified in 5C-3-3/7, is to be considered.
5.7.3(c) Simultaneous Internal Ballast Pressures. In performing a 3D structural analysis, the internal
ballast pressures may be calculated in accordance with 5C-3-3/5.7.3(a) and 5C-3-3/5.7.3(b) above
for tanks in the midbody. For tanks in the fore or aft body, the pressures are to be determined
based on linear distributions of accelerations and ship motions along the length of the vessel.
5.7.4 Deck Cargo Loads
In addition to the static load components of deck cargoes, the inertial forces with respect to the
vertical accelerations, av, are to be considered.

FIGURE 2
Distribution Factor mh (1996)

1.0
Distribution m h

0.0
0.0 0.4 0.6 1.0
Aft Forward
end of L end of L
Distance from the aft end of L in terms of L

FIGURE 3
Distribution Factor fh (1996)

1.0
fh

0.7
Distribution

0.0
0.0 0.2 0.3 0.4 0.60 0.7 0.8 1.0
Aft Forward
end of L end of L
Distance from the aft end of L in terms of L

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FIGURE 4
Distribution of hdi (1996)
h = freeboard to W.L.
Freeboard Deck

hd5 hd1 W.L.

h or h*
whichever is lesser

h hd2
h d3
d4
View from the Stern
Note: h* = ku kc hd1 for nominal pressure
h* = kf ku hd1 for simultaneous pressure

FIGURE 5
Pressure Distribution Function klo (1996)

2.5
Distribution klo

1.5

1.0

0.0
0.0 0.2 0.7 1.0
Aft Forward
end of L end of L
Distance from the aft end of L in terms of L

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FIGURE 6
Distribution Factor mT (1996)
1.0
Factor mT

0.0
0.0 0.2 0.8 1.0
Aft Forward
end of L end of L
Distance from the aft end of L in terms of L

FIGURE 7
Definition of Bow Geometry (1 July 2008)

WLj A B

αij
waterline angle
tangent line

B A

CL

CL CL
highest
deck

Fbi tangent line tangent line

s
normal
body plan
angle βij body plan βij'
angle
WLj

aij
δj
LWL
A-A B-B

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FIGURE 8
Direction of Positive Tangential Force (1996)
Starboard Dec k

FWD BHD

L
C
FWD BHD

Bottom Starboard Wall

L
C

FIGURE 9
Definition of Wall Angle (1996)
Starboard

α = 90

CL α=0

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FIGURE 10
Definition of Cargo Height at Various Locations (1996)

h*
hc hc hc
h*
h* hc
θe hc
θe h*
θe h* hc

L
C L
C
Heavy Cargo (See 5C-3-3/Figure 1)
Light Cargo (See 5C-3-3/Figure 1) Top of the cargo surface inclined 30
To be filled up to the deck line. degrees from the horizontal at the top
of the lower hopper wing tank, and
intersects a vertical line drawn from
the side of the hatch coaming.

FIGURE 11
Definition of Wall Angle for Transverse Bulkhead (1996)
Deck β = 90

FWD BHD

Bottom

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FIGURE 12
Definition of Tank Geometry (1996)

ξ
F.P.

l
δb ξ

l δh

O
ζ O
ζ b

B/2
L
C
h a. Plan View

b δh
δb
B/2 O
L
C ζ
η

η
b. Elevation

For the lower ballast tanks, η is to be measured from a point located at 2/3 the distance from the top of the
tank to the top of the overflow (minimum 760 mm above deck).

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TABLE 1
Combined Load Cases for Bulk, Ore/Bulk/Oil and Ore/Oil Carriers* (2003)
L.C. 1 L.C. 2 L.C. 3 L.C. 4 L.C. 5 L.C. 6 L.C. 7 L.C. 8 L.C. 9 L.C. 10
A. HULL GIRDER LOADS**
Vertical B.M.*** Sag (–) Hog (+) Sag (–) Hog (+) Sag (–) Hog (+) Sag (–) Hog (+) Sag (–) Hog (+)
kc 1.0 1.0 0.7 0.7 0.3 0.3 0.4 0.4 0.4 0.4
Vertical S.F. (+) (–) (+) (–) (+) (–) (+) (–) (+) (–)
kc 0.5 0.5 1.0 1.0 0.3 0.3 0.4 0.4 0.4 0.4
Horizontal B.M. Stbd Tens Port Tens Stbd Tens Port Tens Stbd Tens Port Tens
(–) (+) (–) (+) (–) (+)
kc 0.0 0.0 0.0 0.0 0.3 0.3 0.5 0.5 1.0 1.0
Horizontal S.F. (+) (–) (+) (–) (+) (–)
kc 0.0 0.0 0.0 0.0 1.0 1.0 0.5 0.5 1.0 1.0
Torsional Mt. (–) (+) (–) (+) (–) (+)
kc 0.0 0.0 0.0 0.0 0.6 0.6 1.0 1.0 0.6 0.6
B. EXTERNAL PRESSURE
kc 0.5 0.5 0.5 1.0 0.5 1.0 0.5 1.0 0.5 1.0
kf0 –1.0 1.0 –1.0 1.0 –1.0 1.0 –1.0 1.0 –1.0 1.0
C. INTERNAL BULK CARGO PRESSURE
kc 0.4 0.4 1.0 0.5 1.0 0.5 1.0 0.5 — —
cV 0.8 –0.8 0.8 –0.8 0.4 –0.4 0.7 –0.7 — —
cL Fwd Bhd Fwd Bhd Fwd Bhd Fwd Bhd — — Fwd Bhd Fwd Bhd — —
0.6 –0.6 0.6 –0.6 0.7 –0.7
Aft Bhd Aft Bhd Aft Bhd Aft Bhd — — Aft Bhd Aft Bhd — —
–0.6 0.6 –0.6 0.6 –0.7 0.7
cT — — — — Port Wall Port Wall Port Wall Port Wall — —
–0.9 0.9 –0.7 0.7
— — — — Stbd Wall Stbd Wall Stbd Wall Stbd Wall — —
0.9 –0.9 0.7 –0.7
cφ, Pitch –1.0 1.0 –1.0 1.0 0.0 0.0 –0.7 0.7 — —
cθ, Roll 0.0 0.0 0.0 0.0 1.0 –1.0 0.7 –0.7 — —
D. INTERNAL BALLAST TANK PRESSURE
kc 0.4 0.4 1.0 0.5 1.0 0.5 1.0 0.5 1.0 0.5
wv 0.75 –0.75 0.75 –0.75 0.25 –0.25 0.4 –0.4 0.4 –0.4
wl Fwd Bhd Fwd Bhd - Fwd Bhd Fwd Bhd — — Fwd Bhd Fwd Bhd Fwd Bhd Fwd Bhd
0.25 0.25 0.25 –0.25 0.2 –0.2 0.2 –0.2
Aft Bhd Aft Bhd Aft Bhd Aft Bhd — — Aft Bhd Aft Bhd Aft Bhd Aft Bhd
–0.25 0.25 –0.25 0.25 –0.2 0.2 –0.2 0.2
wt — — — — Port Wall Port Wall Port Wall Port Wall Port Wall Port Wall
–0.75 0.75 –0.4 0.4 –0.4 0.4
— — — — Stbd Wall Stbd Wall Stbd Wall Stbd Wall Stbd Wall Stbd
0.75 –0.75 0.4 –0.4 0.4 Wall -0.4
cφ, Pitch –1.0 1.0 –1.0 1.0 0.0 0.0 –0.7 0.7 –0.7 0.7
cθ, Roll 0.0 0.0 0.0 0.0 1.0 –1.0 0.7 –0.7 0.7 –0.7
E. REFERENCE WAVE HEADING AND POSITION
Heading Angle 0 0 0 0 90 90 60 60 60 60
Heave Down Up Down Up Down Up Down Up Down Up
Pitch Bow Bow Up Bow Bow Up — — Bow Bow Up Bow Bow Up
Down Down Down Down
Roll — — — — Stbd Stbd Up Stbd Stbd Up Stbd Stbd Up
Down Down down
Draft 2/3 1 2/3 1 2/3 1 2/3 1 **** ****

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TABLE 1 (continued)
Combined Load Cases for Bulk, Ore/Bulk/Oil and Ore/Oil Carriers* (2003)
* ku = 1.0 for all load components.
** Boundary forces are to be applied to produce the above specified hull girder bending moment at the middle of the structural
model, and specified hull girder shear force at one end of the middle hold of the model. The sign convention for the shear force
corresponds to the forward end of middle hold. The specified torsional moment is to be produced at the aft bulkhead of the
middle hold.
*** The following still water bending moment (SWBM) is to be used for structural analysis.
L.C. 1, 3 and 5: Maximum sagging SWBM among alternate hold loading conditions only, but not to be taken less than 20% of
the maximum sagging SWBM among all loading conditions.
L.C. 2, 4 and 6: Maximum hogging SWBM among alternate hold loading conditions only, but not to be taken less than 20% of
the maximum hogging SWBM among all loading conditions.
L.C. 7: Maximum sagging SWBM among all loading conditions other than ballast conditions, but not to be taken less than 20%
of the maximum sagging SWBM among all loading conditions.
L.C. 8: Maximum hogging SWBM among all loading conditions other than ballast conditions, but not to be taken less than 20%
of the maximum hogging SWBM among all loading conditions.
L.C. 9: Maximum sagging SWBM among ballast conditions only, but not to be taken less than 20% of the maximum sagging
SWBM among all loading conditions.
L.C. 10: Maximum hogging SWBM among ballast conditions only, but not to be taken less than 20% of the maximum hogging
SWBM among all loading conditions.
**** (2003) For Load Cases 9 and 10, draft d = [47 − 0.11(L − 150)]L/1000 m (ft).

TABLE 2
Values of Ai and Bi *
Ai Bi
−0.05L 1.25 0.3600
FP 1.00 0.4000
0.05L 0.80 0.4375
0.10L 0.62 0.4838
0.15L 0.47 0.5532
0.20L 0.33 0.6666
0.25L 0.22 0.8182
0.30L 0.22 0.8182
* Linear interpolation may be used for intermediate values.

7 Nominal Design Loads (1996)

7.1 General
The nominal design loads specified below are to be used for determining the required scantlings of hull
structures in conjunction with the specified permissible stresses given in Section 5C-3-4.

7.3 Hull Girder Loads – Longitudinal Bending Moments and Shear Forces (1996)
7.3.1 Total Vertical Bending Moment and Shear Force
The total longitudinal vertical bending moments and shear forces may be obtained from the
following equations:
Mt = Msw + kukcMw kN-m (tf-m, Ltf-ft)
Ft = Fsw + kukcFw kN (tf, Ltf)

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where
Msw and Mw are the still-water bending moment and wave-induced bending moment, respectively,
as specified in 3-2-1/3.7, for either hogging or sagging conditions.
Fsw and Fw are the still-water and wave-induced shear forces, respectively, as specified in 3-2-1/3.9,
for either positive or negative shear.
ku is a load factor and may be taken as unity unless otherwise specified.
kc is a correlation factor and may be taken as unity unless otherwise specified.
For determining the hull girder section modulus for 0.4L amidships as specified in 5C-3-4/3, the
maximum still water bending moments, either hogging or sagging, are to be added to the hogging
or sagging wave bending moments, respectively. Elsewhere, the total bending moment may be
directly obtained based on the envelope curves as specified in 5C-3-3/3 and 5C-3-3/5.
For this purpose, ku = 1.0, and kc = 1.0

7.3.2 Horizontal Wave Bending Moment and Shear Force

For non-head sea conditions, the horizontal wave bending moment and the horizontal shear force
as specified in 5C-3-3/5.3 are to be considered as additional hull girder loads, especially for the
design of the side shell and inner skin structures. The effective horizontal bending moment and
shear force, MHE and FHE, may be determined by the following equations:
MHE = kukcMH kN-m (tf-m, Ltf-ft)
FHE = kukcFH kN (tf, Ltf)
where ku and kc are a load factor and a correlation factor, respectively, which may be taken as
unity unless otherwise specified.
7.3.3 Torsional Moment
The effective torsional moments for non-head sea conditions are to be considered in addition to
the hull girder loads specified in 5C-3-3/7.3.1 and 5C-3-3/7.3.2 above.
TME = kukcTM kN-m (tf-m, Ltf-ft)
where
ku and kc are as defined above.
TM is as specified in 5C-3-3/5.3.3.

7.5 Local Loads for Design of Supporting Structures (1996)

In determining the required scantlings of the main supporting structures, such as girders, transverses,
stringers, floors and deep webs, the nominal loads induced by the external and cargo or ballast pressures
distributed over both sides of the structural panel within the cargo hold boundaries are to be considered for
the worst possible load combinations. In general, considerations are to be given to the following two
loading cases accounting for the worst effects of the dynamic load components.
i) Maximum internal cargo pressures for a fully loaded cargo hold with the adjacent holds empty and
minimum external pressures, where applicable.
ii) Empty cargo hold with the fore and aft holds full and maximum external pressures where applicable.
The specified design loads for main supporting structures are given in 5C-3-3/Table 3.

7.7 Local Pressures for Design of Plating and Longitudinals (1996)

In calculating the required scantlings of plating, longitudinals and stiffeners, the nominal pressures are to
be considered for the two load cases given in 5C-3-3/7.5, using ku = 1.1 instead of ku = 1.0 as shown above.
The necessary details for calculating the nominal pressures are given in 5C-3-3/Table 3.

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FIGURE 13
Location of Hold for Nominal Pressure Calculation (1997)

Hold or Tank Considered

5 4 3 2 1

AP
FP

0.4L

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TABLE 3
Design Pressure for Local and Supporting Members (2003)
A. Local Structures—Plating & Long’ls/Stiffeners.
The nominal pressure, p = |pi − pe|, is to be determined from load cases “a” & “b” below, whichever is greater, with
ku = 1.1 and kc = 1.0, unless otherwise specified in the table.
Case “a” Case “b”
At Forward end of the tank or hold At Mid-Tank/Forward end of tank or hold

Structural Members/ Draft/Wave Location and Draft/Wave Location and

Components Heading Angle Loading Pattern Coefficients Heading Angle LoadingPattern Coefficients
pi pe pi pe
1. Bottom Plating 2/3 scantling Full double bottom Ati Ae Scantling Midtank of empty — Be
and Long’l draft/0° ballast tank draft/0° double bottom ballast
tanks
2. Inner Bottom 2/3 scantling Full double bottom Ati — Scantling Fwd end of full cargo Abi —
Plating & Long’l draft/0° ballast tank cargo draft/0° hold, ballast tanks empty
(dry cargo holds) holds empty
Inner Bottom 2/3 scantling Full ballast hold, Ati —
Plating & Long’l draft/0° double bottom
(ballast or liquid ballast tanks empty
cargo holds)
3. Side Shell Plating 2/3 scantling Starboard side of full Bti Ae Scantling Midtank of empty ballast — Be
& Long’l draft/60° ballast tank draft/60° tanks
Side Shell Plating 2/3 scantling Starboard side of full Bti —
(ballast or liquid draft/60° ballast or liquid
cargo holds) cargo holds, adjacent
tanks empty
4. Hold Frame (dry Scantling Empty cargo hold — Be 2/3 scantling Empty cargo hold — Be
cargo holds) draft/0° draft/0°
Hold Frame 2/3 scantling Starboard side of full Bti Ae
(ballast or liquid draft/60° ballast or liquid
cargo holds) cargo holds
5. Side Frame in Scantling Empty cargo hold — Be 2/3 scantling Empty cargo hold — Be
double hull side draft/0° draft/0°
spaces (void)

Side Frame in 2/3 scantling Starboard side of full Bti Ae

double hull side draft/60° ballast
spaces (ballast
tank)
6. Deck Plating & 2/3 scantling Full ballast tank Cti —
Long’l (ballast draft/0°
tank)
Cross Deck 2/3 scantling Full ballast hold Cti —
Structure (ballast draft/0°
hold)
7. Lower Wing Tank Scantling Full cargo hold, Bbi — 2/3 scantling Fwd end and full port Bti —
Sloping Bulkhead draft/60° ballast tanks empty draft/60° and starboard ballast
Plating & Long’l tanks cargo hold empty
(dry cargo holds)
Lower Wing Tank 2/3 scantling Starboard side of full Bti —
Sloping Bulkhead draft/60° ballast or liquid
Plating & Long’l cargo holds, adjacent
(ballast or liquid tanks empty
cargo holds)

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TABLE 3 (continued)
Design Pressure for Local and Supporting Members (2003)
A. Local Structures—Plating & Long’ls/Stiffeners.
The nominal pressure, p = |pi − pe|, is to be determined from load cases “a”& “b” below, whichever is greater, with
ku = 1.1 and kc = 1.0, unless otherwise specified in the table

Case “a” Case “b”

At Forward end of the tank or hold At Mid-Tank/Forward end of tank or hold

Structural Members/ Draft/Wave Location and Draft/Wave Location and Loading

Components Heading Angle Loading Pattern Coefficients Heading Angle Pattern Coefficients
pi pe pi pe
8. Upper Wing Tank 2/3 scantling Starboard side of full Bti — 2/3 scantling Port side of full ballast Bti —
Sloping Bulkhead draft/60° ballast tanks, cargo draft/60° tanks, cargo hold empty
Plating & Long’l hold empty
(dry cargo holds)
Upper Wing Tank 2/3 scantling Starboard side of full Bti —
Sloping Bulkhead draft/60° ballast or liquid
Plating & Long’l cargo holds, adjacent
(ballast or liquid tanks empty
cargo holds)
9. All Other Long’l Scantling Full cargo hold, Bbi — 2/3 scantling Forward end and full Bti —
Bulkhead Plating draft/60° ballast tanks or draft/60° port and starboard
(dry cargo holds) double hull void ballast tanks, double hull
spaces empty void spaces and cargo
hold empty
All Other Long’l 2/3 scantling Starboard side of full Bti —
Bulkhead Plating draft/0° ballast or liquid
(ballast or liquid cargo holds, adjacent
cargo holds) tanks or double hull
void spaces empty
10. Transverse 2/3 scantling Forward bulkhead of Abi — Flooded
Bulkhead Plating draft/0° full cargo hold, Condition
& Stiffeners (dry adjacent holds empty (see note 7)
cargo holds)
Transverse 2/3 scantling B/4 off vessel’s Bti —
Bulkhead Plating draft/60° centerline of full
& Stiffeners ballast hold, adjacent
(ballast or liquid holds empty
cargo holds)
Transverse 2/3 scantling Forward bulkhead of Ati —
Bulkhead Plating draft/0° full ballast tank,
& Stiffeners (all adjacent tanks empty
other tanks)

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TABLE 3 (continued)
Design Pressure for Local and Supporting Members (2003)
B. Main Supporting Members
The nominal pressure, p = |pi − pe|, is to be determined at the mid span of the structural members at starboard side of vessel
from load cases “a”& “b” below, whichever is greater, with ku = 1.0 and kc = 1.0, unless otherwise specified in the table.

Case ‘‘a’’ Case ‘‘b’’

At Mid-tank or Mid-hold for Transverses At Mid-tank or Mid-hold for Transverses

Structural Members/ Draft/Wave Location and Draft/Wave Location and Loading

Components Heading Angle Loading Pattern Coefficients Heading Angle Pattern Coefficients
pi pe pi pe
11. Double Bottom 2/3 scantling Full cargo hold, Abi Ae Scantling Mid-tank, cargo holds — Be
Floor & Girder draft/0° ballast tanks empty draft/90° and ballast tanks empty

12. Bottom Transverse 2/3 scantling Full lower wing tank Ati Ae Scantling Empty lower wing tank — Be
in Lower Wing draft/0° draft/90°
Tank
13. Side Transverse in 2/3 scantling Full lower wing tank Bti Ae Scantling Empty lower wing tank — Be
Lower Wing Tank draft/60° draft/90°
14. Side Transverse in 2/3 scantling Full upper wing tank Bti — Scantling Empty upper wing tank — Be
Upper Wing Tank draft/60° draft/90°
15. Deck Transverse 2/3 scantling Full upper wing tank Bti —
in Upper Wing draft/60°
Tank
16. Sloping Bulkhead Scantling Full cargo hold, Bbi — 2/3 scantling Full lower wing tank, Bti —
Transverse in draft/60° lower wing tank draft/60° cargo hold empty
Lower wing Tank empty
(dry cargo holds)
Sloping Bulkhead 2/3 scantling Full ballast or liquid Bti —
Transverse in draft/60° cargo holds, lower
Lower wing Tank wing tank empty
(ballast and liquid
cargo holds)
17. Sloping Bulkhead 2/3 scantling Full upper wing tank Bti —
Transverse in draft/60°
Upper Wing Tank
(dry cargo holds)
Sloping Bulkhead 2/3 scantling Full hold with ballast Bti —
Transverse in draft/60° or liquid cargo,
Upper Wing Tank upper wing tank
(ballast or liquid empty
cargo holds)
18. Horizontal Girder 2/3 scantling Forward bulkhead of Abi — 2/3 scantling Aft bulkhead of full Cbi —
and Vertical Web draft/0° full cargo hold, draft/0° cargo hold, adjacent
on Transverse adjacent holds empty holds empty
Bulkhead (dry
cargo holds)
Horizontal Girder 2/3 scantling Forward bulkhead of Bti — 2/3 scantling Aft bulkhead of full Dti —
and Vertical Web draft/60° full ballast hold, draft/60° forepeak tank, adjacent
on Transverse adjacent holds empty hold empty
Bulkhead (ballast
or liquid cargo
holds and fore
peak tank)

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TABLE 3 (continued)
Design Pressure for Local and Supporting Members (2003)
B. Main Supporting Members
The nominal pressure, p = |pi − pe|, is to be determined at the mid span of the structural members at starboard side of vessel
from load cases “a”& “b” below, whichever is greater, with ku = 1.0 and kc = 1.0, unless otherwise specified in the table.

Case “a” Case “b”

At Mid-tank or Mid-hold for Transverses At Mid-tank or Mid-hold for Transverses

Structural Members/ Draft/Wave Location and Draft/Wave Location and Loading

Components Heading Angle Loading Pattern Coefficients Heading Angle Pattern Coefficients
pi pe pi pe
19. Diaphragms and Scantling Empty cargo hold, — Be Scantling Empty cargo hold, — Be
Stringers in double draft/0° double hull side draft/0° double hull side tanks or
hull side tanks or tanks or void spaces void spaces empty
void spaces (dry empty
cargo holds)
Diaphragms and 2/3 scantling Starboard side of full Bti Ae
Stringers in double draft/60° ballast or liquid
hull side tanks or cargo holds, double
void spaces hull side tanks full
(ballast or liquid
cargo holds)
20. Deck Girder and 2/3 scantling Full hold with ballast Bti —
Hatch-End Beam draft/60° or liquid cargo

Notes:
1 For calculating pi and pe, the necessary coefficients are to be determined based on the following designated
groups:
a) For pti (ballast or liquid cargo pressure):
Ati: wv = 0.75, wl(forward bulkhead) = 0.25, wl(aft bulkhead) = −0.25, wt = 0.0,
Cφ = −1.0, Cθ = 0.0
Bti: wv = 0.4, wl(forward bulkhead) = 0.2, wl(aft bulkhead) = −0.2, wt(starboard) = 0.4,
wt(port) = −0.4, Cφ = −0.7, Cθ = 0.7
Cti: wv = −0.75, wl(forward bulkhead) = 0.25, wt = 0.0, Cφ = −1.0, Cθ = 0.0
Dti: wv = 0.4, wl(forward bulkhead) = −0.2, wl(aft bulkhead) = 0.2, wt(starboard) = 0.4,
wt(port) = −0.4, Cφ = 0.7, Cθ = 0.7
b) For pbi (dry cargo pressure):
Abi: cV = 0.8, cL(forward bulkhead) = 0.6, cL(aft bulkhead) = −0.6, cT = 0, Cφ = −1.0,
Cθ = 0.0
Bbi: cV = 0.7, cL(forward bulkhead) = 0.7, cL(aft bulkhead) = −0.7, cT(starboard) = 0.7,
cT(port) = −0.7, Cφ = −0.7, Cθ = 0.7
Cbi: cV = 0.8, cL(forward bulkhead) = −0.6, cL(aft bulkhead) = 0.6, cT = 0, Cφ = 1.0,
Cθ = 0.0
c) For pe:
Ae: klo = 1.0, ku = 1.0, kc = −0.5
Be: klo = 1.0

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TABLE 3 (continued)
Design Pressure for Local and Supporting Members (2003)
2 (1997) For structures within 0.4L amidships, the nominal pressure is to be calculated for a hold located
amidships. Each cargo hold or ballast hold in the region should be considered as located amidships as
shown in 5C-3-3/Figure 13.
3 For structures outside 0.4L amidships, the nominal pressure is to be calculated for members in a tank under
consideration.
4 In calculation of the nominal pressure, ρ g of the liquid or ballast is not to be taken less than 1.005 N/cm2-m
(0.1025 kgf/cm2-m, 0.4444 lbf/in2-ft)
5 The cargo specific weight of dry cargoes is defined as cargo weight divided by hold volumes for each
cargo hold. In calculation of the nominal pressure, ρ g of bulk cargo and ore cargo is not to be taken less
than 0.9807 N/cm2-m (0.1 kgf/cm2-m, 0.4336 lbf/in2-ft) and 1.471 N/cm2-m (0.15 kgf/cm2-m, 0.6503
lbf/in2-ft), respectively.
6 Dry cargoes are to be considered to be stored up to the level of the upper deck at centerline. The design
angle of repose of bulk and ore cargoes may be taken as 30 degrees, unless otherwise specified by designers.
7 (1 July 1998) The nominal pressure in the flooded holds may be approximated by taking 70% of the
nominal ballast pressure as specified for transverse bulkhead plating and stiffeners (ballast or liquid cargo
holds), except for single or double side skin vessels intended to carry solid bulk cargoes having a density
of 1.0 t/m3 (62.4 lb/ft3) or above. For these vessels, the flooding loads and the strength assessment are to be
carried out in accordance with 5C-3-A5b/1.
8 Where cargo is carried on deck, the nominal pressure of deck structures is not to be taken less than the
specified cargo pressure.

9 Combined Load Cases (1996)

9.1 Combined Load Cases for Structural Analysis (1996)

For assessing the strength of the hull girder structures and in performing a structural analysis as outlined in
Section 5C-3-5, the ten combined load cases specified in 5C-3-3/Table 1 are to be considered. 5C-3-5/9.9
specifies the load cases to be investigated in assessing the adequacy of structure in each designated hold.
Additional combined load cases may be required as warranted. The loading patterns are shown in
5C-3-3/Figure 1 for three cargo hold lengths. The necessary factors and coefficients for calculating hull
girder and local loads are given in 5C-3-3/Table 1. The total external pressure distribution including static
and hydrodynamic pressure is illustrated in 5C-3-3/Figure 14.

9.3 Combined Load Cases for Total Strength Assessment (1996)

For assessing the failure modes with respect to material yielding, buckling and ultimate strength, the
following combined load cases shall be considered.
9.3.1 Ultimate Strength of Hull Girder
For assessing ultimate strength of the hull girder, the combined effects of the following primary
and local loads are to be considered.
9.3.1(a) Primary Loads, Longitudinal Bending Moments and Shear Forces in Head Sea Conditions
(MH = 0, FH = 0, TM = 0)
Mt = Msw + kukcMw, kc = 1.0 hogging and sagging
Ft = Fsw + kukcFw, kc = 1.0 positive and negative

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Section 3 Load Criteria 5C-3-3

where
ku = 1.15. For vessels with heavy ballast draft forward less than 0.04L or with
flare parameter Ar exceeding 21 m (68.9 ft), ku is to be increased as may be
required by 5C-3-3-/11.1.3 or 5C-3-3/11.3.3, whichever is greater
Msw, Mw, Fsw and Fw are as defined in 3-2-1/3.
Ar is as defined in 5C-3-3/11.3.3.
9.3.1(b) Local Loads for Large Stiffened Panels. Internal and external pressure loads as given in
Note 1 of 5C-3-3/Table 3 are to be considered.
9.3.2 Yielding, Buckling and Ultimate Strength of Local Structures
For assessing the yielding, buckling and ultimate strength of local structure, the ten combined load
cases as given in 5C-3-3/Table 1 are to be considered.
9.3.3 Fatigue Strength
For assessing the fatigue strength of structural joints, the ten combined load cases given in 5C-3-3/9.1
are to be used for a first level fatigue strength assessment as outlined in Appendix 5C-3-A1
“Guide for the Fatigue Assessment of Bulk Carriers.”

FIGURE 14
Illustration of Determining Total External Pressure (1996)

h
hd1

h or h*
whichever is lesser

hd : Hydrodynamic Pressure Head (indicates negative)

hs : Hydrostatic Pressure Head in Still Water

: Total External Pressure Head

Note: h* = ku kc hd1 for nominal pressure

h* = kf ku hd1 for simultaneous pressure

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Section 3 Load Criteria 5C-3-3

11 Impact Loads (1996)

11.1 Bottom Slamming

For bulk carriers with a heavy ballast draft forward less than 0.04L but greater than 0.025L, bottom slamming
loads are to be considered for assessing strength of the flat of bottom plating forward and the associated
stiffening system in the fore body region. For this assessment, the heavy ballast draft forward may be
determined with one cargo hold, adapted for carriage of water ballast at sea, full. In addition, the effects of
the slamming loads on the hull girder bending moments are also to be considered for assessing strength of
the fore body structures
11.1.1 Bottom Slamming Pressure (2001)
The equivalent bottom slamming pressure for strength formulation and assessment should be
determined based on well-documented experimental data or analytical studies. When these direct
calculations are not available, nominal bottom slamming pressures may be determined by the
following equations:

Psi = kki [ vo2 + MViEni]Ef kN/m2 (tf/m2, Ltf/ft2)

where
Psi = equivalent bottom slamming pressure for section i
k = 1.025 (0.1045, 0.000888)
ki = 2.2 b*/do + α ≤ 40

b* = half width of flat of bottom at the i-th ship station, see 5C-3-3/Figure 15
do = 1/
10 of the section draft at the heavy ballast condition, see 5C-3-3/Figure 15

α = a constant as given in 5C-3-3/Table 4

where b represents the half breadth at the 1/10 draft of the section, see 5C-3-3/Figure 15. Linear
interpolation may be used for intermediate values.
Ef = f1 ω1 (L)1/2, ω1 is defined in 5C-3-3/11.1.3
f1 = 0.004 (0.0022) for m (ft)
Ef need not be taken greater than 0.1(11 − 0.01L)1/2 for SI or MKS Units [0.0175(360 − 0.1L)1/2
for U.S. Units].
V = 75% of the design speed Vd in knots. V is not to be taken less than 10 knots.
vo = co(L)1/2, in m/s (ft/s)
co = 0.29 (0.525) for m (ft)
L = vessel length, as defined in 3-1-1/3.1
MRi = c1Ai(VL/Cb)1/2
c1 = 0.44 (2.615) for m (ft)
MVi = BiMRi
Ai and Bi are as given in 5C-3-3/Table 2.
2 2
Gei = e[ − (vo / MVi + di / M Ri )]

di = local section draft, in m (ft)

Eni = natural log of ni
ni = 5730(MVi/MRi)1/2 Gei, if ni < 1 then Psi = 0

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Section 3 Load Criteria 5C-3-3

TABLE 4
Values of α
b/do α b/do α
1.00 0.00 4.00 20.25
1.50 9.00 5.00 22.00
2.00 11.75 6.00 23.75
2.50 14.25 7.00 24.50
3.00 16.50 7.50 24.75
3.50 18.50 25.0 24.75

11.1.2 Simultaneous Slamming Pressures

For performing structural analyses to determine overall responses of bottom structures of the first
two cargo holds from the FP, the spatial distributions of instantaneous bottom slamming pressures
on the forward bottom region are shown in 5C-3-3/Figure 15 and 5C-3-3/Figure 16. The
instantaneous girth-wise distribution at station i, as shown in 5C-3-3/Figure 15, may be assumed
to be uniformly distributed over the flat portion of the bottom structures. The largest value of Psi,
determined within the bound of each of the two cargo holds, is to be used as the respective peak
value of the bottom pressure distribution in the longitudinal direction, 5C-3-3/Figure 16, for each
cargo hold. This peak value may cover 0.01L portion of the ship bottom and it may be placed at
the mid-section of the cargo hold considered. The base of this distribution may cover 0.15L of the
ship bottom on either side of this mid-section of the cargo hold, but need not go beyond 0.05L aft
of the FP.
11.1.3 Effects of Bottom Slamming on Vertical Hull Girder Bending Moment
In addition to the effects of bottom slamming on the bottom structures, the vibratory responses
induced by bottom slamming on the hull girder in terms of vertical bending moment are also to be
considered in the strength assessment as given below.
The load factor, ku, for hull girder ultimate strength assessment in association with wave induced
hogging moment is not to be less than 1.15 or the following, whichever is greater.

ku = (1 + M si2 / M wi
2 1/2
)
where
Mwi = wave induced hogging bending moment, as specified in 3-2-1/3.5.1, for ship
station i.
Msi = k Γi × 108 [b/(ω1dm)]3 [Fn/L4] × Mw10. Bottom slamming induced vertical bending
moment of ship station i – station 10 being the midship, and station 0, the FP.
k = 1.0 (115.74) for m (ft)
Γi = envelope curve factors: 2.05, 2.50, 2.35, 2.21, 1.84, 1.84, 2.16, 1.56,
corresponding to ship stations at 0.2, 0.3, 0.35, 0.4, 0.5, 0.6, 0.7 and 0.8 L,
respectively, measured from the FP. Linear interpolation may be used for
intermediate values.
b = average value of the half breadths at the 1/10 draft of the 6 forward stations,
starting from station 0, the FP, to station 5, the forward quarter length of the
vessel.
dm = average value of 1/10 drafts at the heavy ballast condition of 6 forward stations,
starting from station 0, the FP, to station 5, the quarter length of the vessel.
Fn = 0.514 Vd /(gL)1/2 for SI and MKS units (1.688 Vd /(gL)1/2 for US units), Vd is
the design speed in knots, g is the acceleration due to gravity (9.807 m/sec2,
32.2 ft/sec2). Fn need not be taken greater than 0.17.

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ω1 = natural angular frequency of the hull girder 2-node vertical vibration of the
vessel in the wet mode and the heavy ballast draft condition, in rad/second. If
not known, the following equation may be used.

= μ[B D3/(ΔS Cb3 L3)]1/2 + co ≥ 3.7

where
μ = 23400 (7475, 4094)
ΔS = Δb[1.2 +B/(3db)]
Δb = vessel displacement at the heavy ballast condition, in kN (tf, Ltf)
db = mean draft of vessel at the heavy ballast condition, in m (ft)
co = 1.0 for heavy ballast draft
L, B and D are as defined in Section 3-1-1.
Cb is as defined in 3-2-1/3.5.1.
For vessels with conventional ship forms and cargo hold arrangements, and a forward draft less
than 0.04L but greater than or equal to 0.03L, ku may be approximated from the envelope curves
given in 5C-3-3/Figure 17. Linear interpolation may be used for determining intermediate values.

11.3 Bowflare Slamming

For vessels possessing bowflare and having a shape parameter Ar (defined in 5C-3-3/11.3.3) greater than
21 m (68.9 ft) in the forebody region, bowflare slamming loads are to be considered for assessing the
strength of the side plating and the associated stiffening system in the forebody region of the vessel at its
scantling draft.
11.3.1 Nominal Bowflare Slamming (1 July 2008)
When experimental data or direct calculation is not available, nominal bowflare slamming pressures
may be determined by the following equations:
Pij = Poij or Pbij as defined below, whichever is greater

Poij = k1(9MRi − hij2 )1/2 kN/m2 (tf/m2, Ltf/ft2)

Pbij = k2 k3{C2 + KijMVi[1 + Eni]} kN/m2 (tf/m2, Ltf/ft2)

where
k1 = 9.807 (1, 0.0278)
k2 = 1.025 (0.1045, 0.000888)

k3 = 1 for hij ≤ hb*

= 1 + (hij/ hb* – 1)2 for hb* < hij < 2 hb*

= 2 for hij ≥ 2 hb*

hij = vertical distance measured from the load waterline (LWL) at station i to WLj
on the bowflare. The value of hij is not to be taken less than hb* . Pbij at a
location between LWL and hb* above LWL need not be taken greater than
*
pbij .

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hb* = 0.005(L – 130) + 3.0 (m) for L < 230 m

= 0.005(L – 426.4) + 9.84 (ft) for L < 754 ft
= -3
7.143 × 10 (L – 230) + 3.5 (m) for 230 m ≤ L < 300 m
= 7.143 × 10-3(L – 754.4) + 11.48 (ft) for 754 ft ≤ L < 984 ft
= 4.0 m (13.12 ft) for L ≥ 300 m (984 ft)
*
pbij = Pbi* β i* β ij′

Pbi* = Pbij at hb* above LWL

C2 = 39.2 (422.46) for m (ft)
nij = 5730(MVi/MRi)1/2 Gij ≥ 1.0
Eni = natural log of nij
( − hij2 / M Ri )
Gij = e
MRi = see 5C-3-3/11.1.1
MVi = BiMRi, where Bi is given in 5C-3-3/Table 2.

Kij = fij [rj/(bbij + 0.5hij)]3/2 [lij/rj] [1.09 + 0.029V − 0.47Cb]2

rj = (MRi)1/2

bbij = bij − bi0 > 2.0 m (6.56 ft)

bij = local half beam of WLj at station i. The value of bij is not to be taken less than
2.0 (6.56) m (ft).
bi0 = load waterline half beam at station i

lij = longitudinal distance of WLj at station i measured from amidships.

fij = [90/ β ij′ − 1]2 [tan2( β ij′ )/9.86] cos γ

β ij′ = normal local body plan angle

= tan-1[tan(βij)/cos(αij)]
αij = waterline angle as in 5C-3-3/Figure 7
βij = local body plan angle measured from the horizontal, in degrees, need not be
taken greater than 75 degrees, see 5C-3-3/Figure 18

β i* = β ij′ at hb* above LWL

V = as defined in 5C-3-3/11.1
L = as defined in 3-1-1/3.1, in m (ft)
Cb = as defined in 3-2-1/3.5.1 and not to be less than 0.6.

γ = ship stem angle at the centerline measured from the horizontal,

5C-3-3/Figure 19, in degrees, not to be taken greater than 75 degrees.

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11.3.2 Simultaneous Bowflare Slamming Pressure

For performing structural analyses to determine overall responses of the hull structures, the spatial
distribution of instantaneous bowflare slamming pressures on the fore body region of the hull may
be expressed by multiplying the calculated maximum bowflare slamming pressures, Pij, at forward
ship stations by a factor of 0.71 for the region between the stem and 0.3L from the FP.
11.3.3 Effects of Bowflare Slamming on Vertical Hull Girder Bending Moment and Shear Force (2002)
The ultimate strength of the hull girder in the forward half-length is to be evaluated as follows.
The load factor, ku, for hull girder ultimate strength assessment in association with wave induced
sagging moment is not to be less than 1.15 or the following, whichever is greater.

ku = k{αi(Δ B d/L3) Ar Fn1/3 /ω1}/|Mwi|

where
|Mwi| = absolute value of the wave-induced bending moment at the station i, as
specified in 3-2-1/3.5 for sagging conditions, where station 10 denotes the
midship.
k = 9.81 (1.0, 3.28) for m (ft)
αi = envelope curve factors: 9516, 19032, 28382, 32054, 32722, and 31387,
corresponding to stations at 0.1, 0.2, 0.3, 0.35, 0.4, and 0.5L from the FP,
respectively. Linear interpolation may be used for intermediate values.
Δ = vessel displacement at the scantling draft in kN (tf, Ltf)
Fn = 0.514 Vd /(gL)1/2 for SI and MKS units (for US units, 1.688 Vd /(gL)1/2), Vd is
the design speed in knots, g is the acceleration due to gravity (9.807 m/sec2,
32.2 ft/sec2). Fn need not be taken greater than 0.17.
Ar = the maximum value of Ari in the forebody region
Ari = bowflare shape parameter at a station i forward of the quarter length, up to
the FP of the vessel, to be determined between the LWL and the upper
deck/forecastle, as follows:
(bT/H)2 ∑bj[1 + (sj/bj)2]1/2, j = 1, n; n ≥ 3
where
n = number of segments

bT = ∑b j

H = ∑s j

bj = local change (increase) in beam for the j-th segment at station i (see
5C-3-3/Figure 18)
sj = local change (increase) in freeboard up to the highest deck for the j-th
segment at station i forward (see 5C-3-3/Figure 18)
ω1 = natural frequency of the 2-node hull girder vibration of the vessel in the wet
mode, in rad/second. If not known, the following equation may be used.
= μ[BD3/(ΔsCb3L3)]1/2 + 0.7 ≥ 3.7
μ = 23400 (7475, 4094)
Δs = Δ[1.2 + B/(3d)]
L, B and d are as defined in Section 3-1-1.

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The load factor, ku, for hull girder ultimate strength assessment in association with the positive
wave-induced shear force is not to be less than 1.15 or the following, whichever is greater.
ku = KsiN4
where
Fwi = positive wave-induced shear force (see 3-2-1/3.5.3) at station i, where station
10 denotes the midship, kN (tf, Ltf)

N4 = [c2(Δ B d/L4) Ar Fn1/3 /ω1]/Fw4

= ratio of total wave-induced and wave-induced vertical shear force for ship
station 4 or 0.2L from the FP.
c2 = 9.8k × 104
Ksi = shear envelope curve factor at station i
= 0.95 for station 2 and forward
= 1.0 for stations 3 to 6
= 1.05/N4 for station 10
Linear interpolation may be used for intermediate values.
For vessels with a shape parameter, Ar, less than or equal to 27 m (88.6 ft), the total wave induced
vertical bending moments and shear forces may be determined from the envelope curves given in
5C-3-3/Figure 20 and 5C-3-3/Figure 21, respectively. Linear interpolation may be used for determining
intermediate values.

11.5 Load Cases for Structural Analysis with Respect to Slamming

When structural analysis for bottom and bowflare slamming is preferable, the load cases given in Appendix
5C-3-A4 may be used as reference.

13 Other Loads (1996)

13.1 Thermal and Ice Loads

For vessels intended for special services such as carrying hot cargoes or navigating in cold regions,
consideration is to be given to the effects of thermal and ice loads in assessing the strength of the hull
structure.
In this case, the limits of the thermal and ice loads are to be furnished and analyzed by the designer.

13.3 Accidental Loads

It is advisable to give due consideration to the effects of possible accidental loads on the stiffening systems
in the design of the main supporting members of the side and bottom shell structures. The pressures for
flooded condition, as specified in 5C-3-4/25.7, for corrugated cargo hold bulkheads and nominal magnitudes
of the accidental loads with respect to collision or grounding as outlined in the Guide for Assessing Hull-
girder Residual Strength may be regarded as appropriate in this regard.

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Section 3 Load Criteria 5C-3-3

FIGURE 15
Distribution of Bottom Slamming Pressure
Along the Section Girth (1996)
centerline

b* do (1/10 draft)

Ps

FIGURE 16
Distribution of Bottom Slamming Pressure
Along the Ship Bottom (1996)
FP

Cargo hold 2 Cargo hold 1

0.15L

Ps2
0.05L
Ps1
L/100
L/100

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Section 3 Load Criteria 5C-3-3

FIGURE 17
Total Vertical Bending Moment Distribution
(Wave and Bottom Slamming) (1996)

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Section 3 Load Criteria 5C-3-3

FIGURE 18
Definition of Bowflare Geometry for Bowflare Shape Parameter (1996)

highest deck b4

s4

s3
b3
s2
βij
(body plan angle)

b2

s1

b1
LWL
centerline

FIGURE 19
Ship Stem Angle, γ (1996)
F.P.

Stem Angle γ

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Section 3 Load Criteria 5C-3-3

FIGURE 20
Total Vertical Bending Moment Distribution
(Wave and Bowflare Slamming) (1996)

Ar = 27
1.25

Ar = 21
1.15
ku (Mwi/Mw10)

0.5L 0.65L FP

FIGURE 21
Total Vertical Shear Force Distribution
(Wave and Bowflare Slamming) (1996)
Ar = 27
1.40

Ar = 21
1.15

0.86
0.805
ku (Fwi/Fw4)

0.5L 0.6L 0.7L 0.85L FP

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 347
PART Section 4: Initial Scantling Criteria

5C
CHAPTER 3 Vessels Intended to Carry Ore or Bulk Cargoes
(150 meters (492 feet) or more in Length)

SECTION 4 Initial Scantling Criteria

1 General

1.1 Strength Requirement (1996)

This section specifies the minimum strength requirements for the hull structure with respect to the
determination of the initial scantlings, including the hull girder, shell and bulkhead plating, frames/
stiffeners and main supporting members. Once the minimum scantlings are determined, the strength of the
resulting design is to be assessed in accordance with Section 5C-3-5. The assessment is to be carried out by
means of an appropriate structural analysis as per 5C-3-5/9 in order to establish compliance with the failure
criteria in 5C-3-5/3. Structural details are to comply with 5C-3-4/1.5 below.
The requirements for the hull girder strength are specified in 5C-3-4/3. The required scantlings of double
bottom structures, side shell, deck, and longitudinal and transverse bulkheads are specified in 5C-3-4/7,
5C-3-4/9, 5C-3-4/15, 5C-3-4/21 and 5C-3-4/23, respectively. 5C-3-4/Figure 1 shows the appropriate
subsections giving scantling requirements for the various structural components of typical bulk carriers. For hull
structures beyond 0.4L amidships, the initial scantlings are determined in accordance with Section 5C-3-6.
In general, webs, girders and transverses are not to be less in depth than specified in 5C-3-4/9 and 5C-3-4/15
as a percentage of the span. Alternative designs with stiffness equivalent to the specified depth/length ratio
and the required section modulus may be considered, provided that the calculated results are submitted for
review.
For ore carriers and ore/oil carriers, the strength requirements are given in Appendix 5C-3-A3.

1.3 Calculation of Load Effects (1996)

Approximation equations are given in 5C-3-4/7 through 5C-3-4/25 and Section 5C-3-6 for calculating the
maximum bending moments and shear forces for hold frames and main supporting members clear of the
end brackets for typical structural arrangements and configurations. For designs with different structural
configurations, these local load effects may be determined from a 3D structural analysis at the early design
stages, as outlined in 5C-3-5/9 for the combined load cases specified in 5C-3-3/9, excluding the hull girder
load components. In this regard, the detailed analysis results are to be submitted for review.

1.5 Structural Details (1996)

The strength criteria specified in 5C-3-4/3 through 5C-3-4/25 are based on assumptions that all structural
joints and welded details are properly designed and fabricated and are compatible with the anticipated
working stress levels at the locations considered. It is critical to closely examine the loading patterns, stress
concentrations and potential failure modes of structural joints and details during the design of highly
stressed regions. In this exercise, failure criteria specified in 5C-3-5/3 may be used to assess the adequacy
of structural details.
To enhance the structural integrity and to prevent possible damage to the side shell, special consideration is
to be given to the structural details in critical areas. These include the connections of the wing tanks, the
hold frame and its end brackets to the side shell, also the connections of extended brackets for continuous
longitudinal members and webs to the side shell in the transition zone between forepeak and No. 1 cargo
hold as shown in 5C-3-6/Figure 5. Additional sample improvements are illustrated in 5C-3-4/Figure 2.

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Section 4 Initial Scantling Criteria 5C-3-4

1.7 Evaluation of Grouped Stiffeners (1 July 2009)

Where several members in a group with some variation in requirement are selected as equal, the section
modulus requirement may be taken as the average of each individual requirement in the group. However,
the section modulus requirement for the group is not to be taken less than 90% of the largest section
modulus required for individual stiffeners within the group. Sequentially positioned stiffeners of equal
scantlings may be considered a group.

FIGURE 1
Scantling Requirement Reference by Subsection (1996)
5C-3-4/21.5 5C-3-4/19.1 5C-3-4/17.3 through 5C-3-4/15.5
5C-3-4/13.1 5C-3-4/21.7 5C-3-4/15.1 5C-3-4/17.9 5C-3-4/15.9
5C-3-4/13.5 5C-3-4/15.7
5C-3-4/13.7 5C-3-4/15.3 5C-3-4/15.9

5C-3-4/25.11

5C-3-4/21.3
5C-3-4/9.3

5C-3-4/25

5C-3-4/9.1
5C-3-4/5

5C-3-4/11
5C-3-4/25.9
5C-3-4/21.1

5C-3-4/21.11

5C-3-4/7.3.2

5C-3-4/13.1
5C-3-4/13.3

5C-3-4/7.5

5C-3-4/7.9
5C-3-4/7.11

5C-3-4/7.3.1 5C-3-4/7.7
5C-3-4/7.13

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Section 4 Initial Scantling Criteria 5C-3-4

FIGURE 2
Improved Structural Connection to Side Shell

NO COPE HOLE
OR IMPROVED COPE HOLE

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Section 4 Initial Scantling Criteria 5C-3-4

3 Hull Girder Strength

3.1 Hull Girder Section Modulus (1996)

3.1.1 Hull Girder Section Modulus Amidships
The required hull girder section modulus amidships is to be calculated in accordance with 3-2-1/3.7,
3-2-1/5 and 3-2-1/9. For the assessment of ultimate strength as specified in Section 5C-3-5 and the
determination of initial net structural scantlings, the net hull girder section modulus amidships,
SMn, is to be calculated in accordance with 5C-3-4/3.1.2 below.

3.1.2 Effective Longitudinal Members

The hull girder section modulus calculation is to be carried out in accordance with 3-2-1/9, as modified
below. To suit the strength criteria based on a “net” ship concept, the nominal design corrosion
values specified in 5C-3-2/Table 1 are to be deducted in calculating the net section modulus, SMn.

3.3 Hull Girder Moment of Inertia (1996)

The hull girder moment of inertia is to be not less than required by 3-2-1/3.7.2.

5 Shearing Strength (1997)

5.1 General
The net thicknesses of the side shell and longitudinal bulkhead plating are to be determined based on the
total vertical shear force, Ft, and the permissible shear stress, fs, given below.
Ft = FS + KuKcFw kN (tf, Ltf)
fs = 11.957/Q kN/cm2 (1.220/Q tf/cm2, 7.741/Q Ltf/in2) at Sea

= 10.87/Q kN/cm2 (1.114/Q tf/cm2, 7.065/Q Ltf/in2) in Port

where
FS = still water shear force based on the envelope curve required by 5C-3-3/3.1 for all
anticipated loading conditions at location considered, in kN (tf, Ltf). Where cargo is
carried in alternate holds, FS may be modified based on 3-2-1/3.9.3.
Fw = vertical wave shear force as given in 3-2-1/3.5.3, in kN (tf, Ltf). Fw for in port
condition may be taken as zero.
Q = material conversion factor
= 1.0 for ordinary strength steel
= 0.78 for Grade H32 steel
= 0.72 for Grade H36 steel
= 0.68 for Grade H40 steel
Ku and Kc may be taken as unity unless otherwise specified.
When a direct calculation is not available, the net thickness of the side shell, inner skin and wing tank
sloping bulkhead plating may be obtained from the equations given in 5C-3-4/5.3, 5C-3-4/5.5 and 5C-3-4/5.7
below, where the inner skin is located no further than 0.075B from the side shell.
The nominal design corrosion values as given in 5C-3-2/Table 1 for the side shell, inner hull and wing tank
sloping bulkhead plating are to be added to the “net” thickness.

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Section 4 Initial Scantling Criteria 5C-3-4

5.3 Net Thickness of Side Shell Plating

ts ≥ FtDs m/2 I fs cm (in.)
where
I = moment of inertia of the “net” hull girder section at the position considered, in cm4 (in4)
m = first moment of the “net” hull girder section, in cm3 (in3), about the neutral axis, of
the area between the vertical level at which the shear stress is being determined and
the vertical extremity of the section under consideration.
Ft and fs are as defined in 5C-3-4/5.1 above.
Ds = shear distribution factors for side shell are as defined in 5C-3-4/5.3.1, 5C-3-4/5.3.2
and 5C-3-4/5.3.3 below, respectively.
5.3.1 Side Shell in way of the Upper Wing Tank
Ds = 0.912 − 0.35(AUSB/ASU )
where
AUSB = total projected net area of the upper wing tank sloping bulkhead plating, in
cm2 (in2 )
ASU = projected net area of the side shell plating in way of the upper wing tank, in
cm2 (in2 )
5.3.2 Side Shell between the Upper and Lower Wing Tanks
5.3.2(a) Single skin:
Ds = 1.0
5.3.2(b) Double skin (including vessels whose inner skin is less than 1000 mm (39.4 in.) from the
side shell):
Ds = 1 − {AIH /(AIH + ASM)} (1 + bs/B)
where
AIH = total projected net area of the inner hull between the upper and lower wing
tanks, in cm2 (in2)
ASM = projected net area of the side shell between the upper and lower wing tanks,
in cm2 (in2)
bs = distance between the inner hull and the side shell, in m (ft)
B = breadth of the vessel, in m (ft), as defined in 3-1-1/5
5.3.3 Side Shell in Way of the Lower Wing Tank
Ds = 0.74 − 0.3(ALSB /ASL )
where
ALSB = total projected net area of the lower wing tank sloping bulkhead plating, in
cm2 (in2)
ASL = projected net area of the side shell plating in way of the lower wing tank
above the inner bottom level, in cm2 (in2)

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Section 4 Initial Scantling Criteria 5C-3-4

5.5 Net Thickness of the Sloping Bulkhead Plating of Upper and Lower Wing Tanks
tb ≥ FtDSBm/2 I fs
where
DSB = shear distribution factors for the projected sloping bulkhead plating of the upper
and lower wing tanks, depending on the locations are defined in 5C-3-4/5.5.1 and
5C-3-4/5.5.2 below, respectively.
Ft, m, I and fs are as defined above.

5.5.1 Upper Wing Tank Sloping Bulkhead

DSB = 0.4(AUSB /ASU ) + 0.1
where
AUSB = total projected net area of the upper wing tank sloping bulkhead plating, in
cm2 (in2)
ASU = projected net area of the side shell plating in way of the upper wing tank, in
cm2 (in2)
5.5.2 Lower Wing Tank Sloping Bulkhead
DSB = 0.3(ALSB /ASL) + 0.26
where
ALSB = total projected net area of the lower wing tank sloping bulkhead plating, in
cm2 (in2)
ASL = projected net area of the side shell plating in way of the lower wing tank,
above the inner bottom level, in cm2 (in2)

5.7 Net Thickness of the Inner Hull Plating

tIH ≥ FtDIH m/2 I fs
where
DIH = shear distribution factor for the inner hull
= [AIH /(AIH + ASM)](1 + bs /B)
All other parameters are as defined in 5C-3-4/5.3 above.

5.9 Three Dimensional Analysis (1996)

The total shear stress in the side shell, inner hull (on double hull vessels) and wing tank sloping bulkhead
plating (net thickness) may be calculated using a 3D structural analysis to determine the general shear
distribution.

7 Double Bottom Structures

7.1 General (1996)

7.1.1
The depth of the double bottom and arrangement of access openings are to be in compliance with
5C-3-1/1.5 and Section 3-2-4. Centerline and side girders are to be fitted as necessary to provide
sufficient stiffness and strength for docking loads as well as those specified in Section 5C-3-3. The
side girders are to be spaced approximately 3 m (10 ft).
Struts connecting the bottom and inner bottom longitudinals are not to be fitted in the double bottom
of vessels engaged in trade where cargoes are handled by grabs or similar mechanical appliances.

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Section 4 Initial Scantling Criteria 5C-3-4

7.1.2
The net thickness of the flat plate keel is to be not less than that required for the bottom shell
plating at that location by 5C-3-4/7.3.1, increased by 1.5 mm (0.06 in.), except where the submitted
docking plan (see 3-1-2/11) specifies all docking blocks be arranged away from the keel.
7.1.3
The term “bottom shell plating” refers to the plating from the keel to the upper turn of the bilge for
0.4L amidships.
7.1.4 (2004)
Longitudinals around the bilge are to be graded in size from that required for the lowest side
longitudinal to that required for the bottom longitudinals. Where longitudinals are omitted in way
of the bilge, the bottom and side longitudinals are to be arranged so that the distance between the
nearest longitudinal and the turn of the bilge is not more than 0.4s (s is the spacing of bottom or
side longitudinals), as applicable (see-5C-3-4/Figure 2A).

FIGURE 2A

Ss

Ss
b
R. End
R
b ≤ Ss(2/5)

Sb Sb a

a ≤ Sb(2/5)
R. End

7.1.5
Where a hold is to carry special cargoes such as steel coils and containers, double bottom structures
are to be reinforced to withstand the anticipated load. An engineering analysis may be required.
7.1.6
Where ducts forming a part of the double bottom structure are used as a part of the piping system
for transferring cargo oil or ballast, the structural integrity of the duct is to be safeguarded by
suitable relief valves or other arrangement to limit the pressure in the system to the value for
which it is designed.

7.3 Bottom Shell and Inner Bottom Plating (1996)

The net thickness of the bottom shell and inner bottom plating over the midship 0.4L is to satisfy the hull
girder section modulus requirements in 5C-3-4/3.1. The buckling and ultimate strength are to be in
accordance with the requirements in 5C-3-5/5. In addition, the net thickness of the bottom shell and inner
bottom plating are to be not less than the following:

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-3-4

7.3.1 Bottom Shell Plating (1999)

The net thickness of the bottom shell plating, tn, is to be not less than t1, t2 and t3, specified as
follows:
t1 = 0.73s(k1 p/f1)1/2 mm (in.)
t2 = 0.73s(k2 p/f2)1/2 mm (in.)
t3 = cs(Sm fy /E)1/2 mm (in.)
where
s = spacing of bottom longitudinals, in mm (in.)
k1 = 0.342
k2 = 0.500

p = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2) as specified in 5C-3-3/Table 3

Where upper and lower wing tanks are connected by trunks or double sides, the nominal pressure,
p, in the lower wing tank for load case “a” may be modified by the following equation:
p = pa − puh

puh = 0.32γ(hlwttan φe)1/2 where lwt ≥ 0.20L

= 0 where lwt ≤ 0.10L
Linear interpolation is to be used for intermediate values of lwt.
pa is nominal pressure in N/cm2 (kgf/cm2, lbf/in2), as defined in load case “a” in 5C-3-3/Table 3
for bottom plating.
γ = specific weight of the ballast water, 1.005 N/cm2-m (0.1025 kgf/cm2-m,
0.4444 lbf/in2-ft)
h = height of upper wing tank at vessel’s side, in m (ft)
lwt = length of the upper wing tank, in m (ft)
L = vessel length, as defined in 3-1-1/3, in m (ft)
φe = effective pitch amplitude, as defined in 5C-3-3/5.7.3 with Cφ = 1.0
f1 = permissible bending stress, in the longitudinal direction, in N/cm2 (kgf/cm2,
lbf/in2)
= (0.95 − 0.67α1SMRB /SMB)Sm fy ≤ k3 Sm fy
α1 = Sm1fy1/Sm fy
k3 = 0.40 for load case 1 − “a” in 5C-3-3/Table 3

= 0.36 for load case 1 − “b” in 5C-3-3/Table 3

SMRB = reference net hull girder section modulus based on the material factor of the
bottom flange of the hull girder, in cm2-m (in2-ft)
= 0.9 SM
SM = required gross hull girder section modulus at the location under consideration
in accordance with 3-2-1/3.7 and 3-2-1/5.5, based on the material factor of
the bottom flange of the hull girder, in cm2-m (in2-ft)
SMB = design (actual) net hull girder section modulus to the bottom at the location
under consideration, in cm2-m (in2-ft)

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Section 4 Initial Scantling Criteria 5C-3-4

f2 = permissible bending stress, in the transverse direction, in N/cm2 (kgf/cm2,

lbf/in2)
= 0.80 Sm fy
Sm = strength reduction factor
= 1 for Ordinary Strength Steel, as specified in 2-1-2/Table 2
= 0.95 for Grade H32, as specified in 2-1-3/Table 2
= 0.908 for Grade H36, as specified in 2-1-3/Table 2
= 0.875 for Grade H40, as specified in 2-1-3/Table 2
Sm1 = strength reduction factor for the bottom flange of the hull girder
fy = minimum specified yield point of the bottom shell plating, in N/cm2
(kgf/cm2, lbf/in2)
fy1 = minimum specified yield point of the bottom flange of the hull girder, in
N/cm2 (kgf/cm2, lbf/in2)
E = modulus of elasticity of the material, may be taken as 2.06 × 107 N/cm2
(2.1 × 106 kgf/cm2, 30 × 106 lbf/in2) for steel
c = 0.7N2 − 0.2, not to be less than 0.4Q1/2 or 0.5N, whichever is less
N = Rb (Q/Qb)1/2
Rb = (SMRBH /SMB)1/2
SMRBH = reference net hull girder section modulus for hogging bending moment based
on the material factor of the bottom flange of the hull girder, in cm2-m (in2-ft)
= 0.9SMH
SMH = required gross hull girder section modulus in accordance with 3-2-1/3.7.1and
3-2-1/5.5 for hogging total bending moment at the location under consideration,
based on the material factor of the bottom flange of the hull girder, in cm2-m
(in2-ft)
Q, Qb = material conversion factor in 5C-3-4/5 for the bottom plating and the bottom
flange of the hull girder, respectively.
The net thickness, t3, may be determined based on Sm and fy of the hull girder strength material
required at the location under consideration.
Bottom shell plating may be transversely framed in pipe tunnels, provided that the net thickness of
the bottom shell plating, tn, is not less than t4, obtained from the following equation:
t4 = 0.73 sk(k2 p/f1)1/2 mm (in.)
where
s = spacing of the bottom transverse frames, in mm (in.)
k2 = 0.5

k = (3.075 (α)1/2 − 2.077)/( α + 0.272), (1 ≤ α ≤ 2)

= 1.0 (α > 2)
α = aspect ratio of the panel (longer edge/shorter edge)
All other parameters are as defined above.
In addition to the foregoing, the net thickness of the bottom shell plating, outboard of 0.3B from
the centerline of the vessel, is to be not less than that of the lowest side shell plating required by
5C-3-4/9.1, adjusted for the spacing of the longitudinals and the material factors.

356 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-3-4

7.3.2 Inner Bottom Plating (1999)

The net thickness of the inner bottom plating, tn, is to be not less than t1, t2 and t3, specified as
follows:
t1 = 0.73s(k1 p/f1)1/2 mm (in.)
t2 = 0.73s(k2 p/f2)1/2 mm (in.)
t3 = cs(Sm fy /E)1/2 mm (in.)
where
s = spacing of inner bottom longitudinals, in mm (in.)
k1 = 0.342
k2 = 0.50

p = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), as specified in 5C-3-3/Table 3

Where upper and lower wing tanks are connected by trunks or double sides, the nominal pressure,
p, in load case “a” for dry cargo holds may be modified by the following equation:
p = pa − puh
pa is nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), as defined in load case “a” of 5C-3-3/Table 3
for inner bottom plating in dry cargo holds.
puh is as defined in 5C-3-4/7.3.1.
The net thickness, t3, may be determined based on Sm and fy of the hull girder strength material
required at the location under consideration.
The net thickness of the inner bottom plating, outboard of 0.3B from the centerline of the vessel, is
also not to be less than that of the adjacent strake on the lower wing tank sloping bulkhead
required by 5C-3-4/21.1, adjusted for the spacing of the longitudinals and the material factors.
f1 = permissible bending stress, in the longitudinal direction, in N/cm2 (kgf/cm2,
lbf/in2)
= (0.95 − 0.50α1 SMRB /SMB)Sm fy ≤ 0.55Sm fy, where SMB /SMRB is not to be
taken more than 1.4
f2 = permissible bending stress, in the transverse direction, in N/cm2 (kgf/cm2,
lbf/in2)
= 0.85 Sm fy
α1 = Sm1fy1/Sm fy
Sm = strength reduction factor obtained from 5C-3-4/7.3.1 for the steel grade of
the inner bottom plating
Sm1 = strength reduction factor obtained from 5C-3-4/7.3.1 for the steel grade of
the bottom flange of the hull girder
fy = minimum specified yield point of the inner bottom plating, in N/cm2
(kgf/cm2, lbf/in2)
fy1 = minimum specified yield point of the bottom flange of the hull girder, in
N/cm2 (kgf/cm2, lbf/in2)
c = 0.7N2 − 0.2, not to be less than 0.4Q1/2
N = Rb[(Q/Qb)(y/yn)]1/2
Q = material conversion factor in 5C-3-4/5.1 for the inner bottom plating

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Section 4 Initial Scantling Criteria 5C-3-4

y = vertical distance, in m (ft), measured from the inner bottom to the neutral
axis of the hull girder section
yn = vertical distance, in m (ft), measured from the bottom to the neutral axis of
the hull girder section
SMRB, SMB, Rb, Qb and E are as defined in 5C-3-4/7.3.1.
Inner bottom plating may be transversely framed in pipe tunnels, provided the net thickness of the
inner bottom plating, tn, is not less than t4, obtained from the following equation:
t4 = 0.73sk(k2 p/f1)1/2 mm (in.)
where
s = spacing of inner bottom transverse frame, in mm (in.)
k2 = 0.5

k = (3.075 (α)1/2 − 2.077)/(α + 0.272), (1 ≤ α ≤ 2)

= 1.0 (α > 2)
α = aspect ratio of the panel (longer edge/shorter edge)
All other parameters are as defined above.
7.3.2(a) Inner Bottom Plating for Vessels Intended to Use Grabs (1999). Where the vessel is
regularly engaged in trades where the cargoes are handled by grabs, or similar mechanical
appliances, it is recommended that flush inner-bottom plating be adopted throughout the cargo
space. The net thickness of the inner bottom plating is, in addition to that specified above, also not
to be taken less than t5, obtained from the following equation:

t5 = (0.037L + 0.009s) R + 3.5 mm

= (0.000444L + 0.009s) R + 0.138 in.

where
R = 1.0 for ordinary mild steel
= fym/Sm fyh for higher strength material
fym = specified minimum yield point for mild steel, in N/cm2 (kgf/cm2, lbf/in2)
fyh = specified minimum yield point for higher tensile steel, in N/cm2 (kgf/cm2,
lbf/in2)
L = length of vessel, in m (ft), as defined in 3-1-1/3.1
s is as defined above.
It is also required that the net thickness of sloping bulkhead plating of lower wing tanks and lower
stool plating of transverse bulkheads within a vertical extent of 1.5 m above the inner bottom is
not to be taken less than t5 with the actual spacing of the sloping bulkhead and stool stiffeners.
If the vessel is designed to discharge its cargo by a means other than by grabs, or similar
mechanical appliances, which would negate the t5 inner bottom thickness requirement, it is to be
recorded in the vessel’s Loading Manual that grabs, or similar mechanical appliances are not to be
used to discharge cargo.

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Section 4 Initial Scantling Criteria 5C-3-4

7.3.2(b) Optional Supplementary Requirement for Vessels Intended to Use Grabs (2001). Where
the vessel is intended to use a specific weight of grab, the net thickness of inner bottom plating
may be obtained from the following equation:

t6 = k3 Wg ⋅ s ⋅ R / s e mm (in.)

where
k3 = 4.56 (0.181) where Wg is in tonnes (L tons)
Wg = unladen grab weight (mass), in tonnes (L tons)
s = spacing of inner bottom longitudinals, in mm (in.)
R = 1.0 for ordinary mild steel
= fym/Sm fyh for higher strength material
se = 1000 mm (39.37 in.) where Wg ≤ 20
tonnes (19.684
Ltons)
= 1000 + (k4Wg − 31.2)103 − Wg 2 / k5 mm where Wg > 20
tonnes
= 39.37[1 + ( (k4Wg − 31.2)103 − Wg 2 / k5 )/1000] in. where Wg >19.684
Ltons
k4 = 1.58 (1.605), where Wg is in tonnes (Ltons)
k5 = 1.0 (0.969)
fym = specified minimum yield point for mild steel, in N/cm2 (kgf/cm2, lbf/in2)
fyh = specified minimum yield point for higher tensile steel, in N/cm2 (kgf/cm2,
lbf/in2)
Sm = strength reduction factor
= 1.0 for mild steel
= 0.95 for HT32 steel
= 0.908 for HT36 steel
The unladen grab weight (mass) used in determining the inner bottom thickness, t6, is to be
recorded in the vessel’s Loading Manual. It should be noted, however, that this does not negate
the use of heavier grabs, but the owner and operators are to be made aware of the increased risk of
local damage and possible early renewal of inner bottom plating if heavier grabs are used regularly
to discharge cargo. The notation GRAB [XX tonnes] placed after the appropriate classification
notation in the Record will signify that the vessel’s inner-bottom has been designed for a specific
grab weight.
7.3.2(c) Inner Bottom Plating for Vessels Intended to Carry Steel Coils (2001). Where the vessel
is intended to carry steel coils in holds, the net thickness of the inner bottom plating is not to be
less than t7, obtained from the following equation:

aϕW1
t7 = mm (in.)
f y Sm

where
a = 1.25 (within 0.4L amidships)
= 1.25 or 1 + 0.568kv ao, whichever is greater, (beyond 0.4L amidships)
kv = acceleration factor, determined as defined in 5C-3-3/5.7.1(c), at the center of
the supported panel under consideration.

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Section 4 Initial Scantling Criteria 5C-3-4

ao = acceleration factor, as defined in 5C-3-3/5.7.1(c), with L in m (ft)

W1 = weight, in kN (tf, Ltf), of steel coils on one inner bottom plating panel
= k6W m n1/n
k6 = 9.8 (1.0, 1.0)
W = weight (mass) of one steel coil, in tonnes (L tons)
n1 = number of tiers of steel coils
n = number of dunnages supporting one steel coil
m = parameter as given in 5C-3-4/Table 1, as a function of n and l/sf
l = length of one steel coil, in m (ft)
sf = floor spacing at the location being consideration, in m (ft)
αδ − δ 2 − 0.25α 2 (1 − β ) 2
ϕ =
αβ (1 + 2αδ )

δ = 0.5[ 1 + 2α 2 + α 4 (1 − β ) 2 − 1] / α

α = aspect ratio of the inner bottom plating panel, (between floors and
longitudinal stiffeners); α is not to be taken more than 3.0
β = parameter, as given in 5C-3-4/Table 1 as a function of n and l/sf
fy = specified minimum yield point of the inner bottom plating, in kN/mm2
(tf/mm2, Ltf/in2)
Sm = strength reduction factor for the steel of the inner bottom plating, as defined
in 5C-3-4/7.3.1
The above equation is applicable for normal loading arrangements where steel coils are stowed on
dunnage laid athwartships, with the steel coils’ axes in fore-and-aft direction. Other loading
arrangements of steel coils will be specially considered. The normal corrosion value is to be added
to the net thickness to obtain the gross required inner bottom thickness. This corrosion value is in
5C-3-2/Table 1 for bulk carriers. The corrosion value for multipurpose vessels can be taken from
5C-3-2/Table 1.

TABLE 1
Parameters m and β as functions of n and l/sf
n l/sf m β
2 0.83 ≤ l/sf 2 0.5 l/sf
2 0.60 ≤ l/sf < 0.83 3 1.2 l/sf
2 0.42 ≤ l/sf < 0.60 4 1.65 l/sf
2 0.30 ≤ l/sf < 0.42 5 2.35 l/sf
3 0.83 ≤ l/sf 3 0.65 l/sf
3 0.65 ≤ l/sf < 0.83 4 1.2 l/sf
3 0.52 ≤ l/sf < 0.65 5 1.53 l/sf
4 0.83 ≤ l/sf 4 0.75 l/sf
4 0.65 ≤ l/sf < 0.83 5 1.2 l/sf

The special comment, “Designed for the carriage of steel coil” will be entered in column 5 of the
Record where the scantlings of double bottom are in compliance with the requirements of the
above and 5C-3-4/7.5, as applicable.

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-3-4

7.5 Bottom and Inner Bottom Longitudinals (2001)

The net section modulus of each bottom or inner bottom longitudinal, or each transverse frame in the pipe
tunnels, in association with the effective plating to which it is attached, is to be not less than obtained from
the following equations:
SM = M/fb cm3 (in3)

M = 1000psl2/k N-cm (kgf-cm, lbf-in)

where
k = 12 (12, 83.33)
s = spacing of longitudinals or transverse frames, in mm (in.)
l = span of longitudinals or transverse frames between effective supports as shown in
5C-3-4/Figure 3, in m (ft)
p = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), as specified in 5C-3-4/7.3.1 and
5C-3-4/7.3.2 for bottom and inner bottom longitudinals or transverse frame,
respectively.
fb = permissible bending stresses, in N/cm2 (kgf/cm2, lbf/in2)

= 1.2 [1.0 − 0.65 α1 SMRB/SMB]Sm fy ≤ 0.55Sm fy for bottom longitudinals

= 1.3 [1.0 − 0.50 α1 SMRB/SMB]Sm fy ≤ 0.65Sm fy for inner bottom longitudinals

= 0.65 Sm fy for inner bottom longitudinals of vessels intended to carry steel coils
(within 0.4L amidships)
= 0.75 Sm fy for inner bottom longitudinals of vessels intended to carry steel coils
(within 0.2L and the ends of L)
between 0.3L and 0.2L from the ends of L of vessels intended to carry steel coils, fb
for inner bottom longitudinals is to be obtained by linear interpolation
= 0.70 Sm fy for transverse frames in pipe tunnels

α1 = Sm1fy1/Sm fy
Sm = strength reduction factor obtained from 5C-3-4/7.3.1 for the steel grade of the
longitudinals considered
Sm1 = strength reduction factor obtained from 5C-3-4/7.3.1 for the steel grade of the bottom
flange of the hull girder
fy = minimum specified yield point of the longitudinals considered, in N/cm2 (kgf/cm2,
lbf/in2)
fy1 = minimum specified yield point of the bottom flange of the hull girder, in N/cm2
(kgf/cm2, lbf/in2)
SMRB and SMB are as defined in 5C-3-4/7.3.1.
The net section modulus of the bottom longitudinals, outboard of 0.3B from the centerline of the vessel, is
also to be not less than that of the lowest side longitudinal required by 5C-3-4/9.3, adjusted for the span
and spacing of the longitudinals and the material factors.
The net section modulus of the inner bottom longitudinals, outboard of 0.3B from the centerline of the
vessel, is also to be not less than that of the lowest longitudinal on the lower wing tank sloping bulkhead
required by 5C-3-4/21.11, adjusted for the span and spacing of the longitudinals and the material factors.
In determining compliance with the foregoing, an effective breadth, be, of the attached plating is to be used
in the calculation of the section modulus of the design longitudinal. be is to be obtained from line b) of
5C-3-4/Figure 4, or alternatively, be may be approximated as being 10% of the span l, defined above.

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The net section modulus of inner bottom longitudinals in association with the effective inner bottom
plating is to be not less than obtained from the following equation:
SM = M/fb cm3 (in3)
where
M = maximum bending moment at the longitudinal, in N-cm (kgf-cm, lbf-in), obtained
with the assumption that the longitudinal is a fixed-fixed beam at floors. The
longitudinal should be loaded with concentrated loads P = 0.8aWn1/n at the position
of dunnages, where W, a, n1, n are as defined in 5C-3-4/7.3.2(c). The span of the
longitudinal is to be defined as shown in 5C-3-4/Figure 3.
fb = permissible bending stress, as defined in 5C-3-4/7.5 for inner bottom longitudinals
Strength and buckling of floors are also to be checked for loading of steel coils.

7.7 Bottom Centerline Girder (2004)

The net thickness of the centerline girder amidships is to be not less than t1 and t2, as defined below:
t1 = (0.045L + 4.5)R mm
= (0.00054L + 0.177)R in.
t2 = 10F1/(db fs) mm
= F1/(db fs) in.
The net thickness, t3, may be determined based on Sm and fy of the hull girder strength material required at
the location under consideration.
t3 = cs(Sm fy/E)1/2 mm (in.)
where F1 is the maximum shear force at the centerline girder, as obtained from the equations given below
(see also 5C-3-4/1.3). Alternatively, F1 may be determined from finite element analyses, as specified in
5C-3-5/9 with the combined load cases in 5C-3-5/9.9. However, in no case should F1 be taken less than
85% of that determined from the equations below:
F1 = 1000kα1γ1n1n2 plss1 N (kgf, lbf), for λ ≤ 1.5

F1 = 345 kγ1n1n2 pbss1 N (kgf, lbf), for λ > 1.5

where
c = 0.7N2 − 0.2, not to be less than 0.4Q1/2, but need not be greater than 0.45(Q/Qb)1/2
N = Rb[(Q/Qb)(y/yn)]1/2
k = 1.0 (1.0, 2.24)
α1 = 0.505 − 0.183λ

λ = ls /bs

γ1 = 2x/(ls − sf) ≤ 1.0

n1 = 0.0374 (s1/sf)2 − 0.326(s1/sf) + 1.289

n2 = 1.3 − (sf /12) for SI or MKS Units

= 1.3 − (sf /39.37) for U.S. Units

ls = unsupported length of the double bottom structure under consideration, in m (ft), as
shown in 5C-3-4/Figure 5.

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bs = unsupported width of the double bottom structures under consideration, in m (ft), as

shown in 5C-3-4/Figure 5.
s1 = sum of one-half of girder spacings on both sides of the centerline girder, in m (ft)
sf = average spacing of floors, in m (ft)
x = longitudinal distance from the mid-span of unsupported length (ls) of the double
bottom to the location of the girder under consideration, in m (ft)
p = nominal pressure, in kN/m2 (tf/m2, Ltf/ft2), as specified in 5C-3-3/Table 3
db = depth of double bottom, in cm (in.)
fs = permissible shear stresses, in N/cm2 (kgf/cm2, lbf/in2)
= 0.50 Sm fy
R = 1.0 for ordinary mild steel
= fym /Sm fyh for higher strength steel

fym = specified minimum yield point for mild steel, in N/cm2 (kgf/cm2, lbf/in2)
fyh = specified minimum yield point for higher tensile steel, in N/cm2 (kgf/cm2, lbf/in2)
L = length of vessel, in m (ft), as defined in 3-1-1/3.1
Rb, Q, Qb, Sm and fy are as defined in 5C-3-4/7.3.1.
y and yn are as defined in 5C-3-4/7.3.2.
Pipe tunnels may be substituted for centerline girders, provided the tunnel is suitably stiffened by fitting
vertical webs, as may be required. The thickness of each girder forming the pipe tunnel and center girder
within the pipe tunnel, if any, is to be not less than that required for the bottom side girder (see 5C-3-4/7.9
and 5C-3-4/7.13) and for docking (see 3-2-4/3.7), as appropriate.

7.9 Bottom Side Girders (1999)

The net thickness of the bottom side girders is to be not less than t1 and t2, as defined below:
t1 = (0.026L + 4.5)R mm
= (0.00031L + 0.177)R in.
t2 = 10F2/(db fs) mm
= F2 /(db fs) in.
The net thickness, t3, may be determined based on Sm and fy of the hull girder strength material required at
the location under consideration.
t3 = cs(Sm fy /E)1/2 mm (in.)
where F2 is the maximum shear force at the side girders under consideration, as obtained from the equations
given below (see also 5C-3-4/1.3). Alternatively, F2 may be determined from finite element analyses, as
specified in 5C-3-5/9 with the combined load cases in 5C-3-5/9.9. However, in no case should F2 be taken
less than 85% of that determined from the equations below.
F2 = 1000kα2β1γ1n3n4 plss2 N (kgf, lbf), for λ ≤ 1.5

F2 = 285kβ1γ1n3n4 pbs s2 N (kgf, lbf), for λ > 1.5

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Section 4 Initial Scantling Criteria 5C-3-4

where
c = 0.7N2 − 0.2, not to be less than 0.4Q1/2, but need not be greater than 0.45(Q/Qb)1/2
k = 1.0 (1.0, 2.24)
α2 = 0.445 − 0.17λ
β1 = 1 − (1.2z1/bs) ≥ 0.6 for loaded holds under alternate loading conditions
= 1.25 − (2z1/bs) ≥ 0.6 for all holds or tanks under all other loading conditions
n3 = 1.072 − 0.0715 (s2 /sf)
n4 = 1.2 − (sf /18) for SI or MKS Units
= 1.2 − (sf /59.1) for U.S. Units
s2 = sum of one-half of girder spacings on both sides of each side girder, in m (ft)
z1 = transverse distance from the centerline of the unsupported width (bs) of the double
bottom to the location of the girder under consideration, in m (ft)
γ1, N, ls, bs, λ, sf, p, db, fs, L and R are as defined in 5C-3-4/7.7.

7.11 Bottom Floors (1997)

The net thickness of the floors is to be not less than t1 and t2, as specified below:
t1 = (0.026L + 4.5)R mm
= (0.0031L + 0.177)R in.
t2 = 10F3/db fs) mm
= F3/(db fs) in.
where F3 is the maximum shear force at the floors under consideration, as obtained from the equation
given below (see also 5C-3-4/1.3). Alternatively, F3 may be determined from finite element analyses, as
specified in 5C-3-5/9 with the combined load cases in 5C-3-5/9.9. However, in no case should F3 be taken
less than 85% of that determined from the equation below.
F3 = 1000 kα3β2β3γ2 p bs sf N (kgf, lbf)
where
k = 1.0 (1.0, 2.24)
α3 = 0.5ρo
ρo = η(0.66 − 0.08η), for η ≤ 2.0
= 1.0 for η > 2.0
β2 = 2 z2/bs
β3 = 1 − 0.4 (z2/bs) for loaded holds under alternate loading conditions
= 1.0 for all holds or tanks under all other loading conditions
γ2 = 1 − (x/ls)(1.245λ + 0.044)
η = (ls/bs)(sg /sf)1/4
sg = average spacing of girders, in m (ft)
sf = sum of one-half of floor spacings on both sides of each floor, in m (ft)
x = longitudinal distance from the mid-span of unsupported length (ls) of the double
bottom to the location of the floor under consideration, in m (ft)

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Section 4 Initial Scantling Criteria 5C-3-4

z2 = transverse distance from the centerline of the unsupported width (bs) of the double
bottom to the location of floor under consideration, in m (ft)
fs = 0.50 Sm fy in N/cm2 (kgf/cm2, lbf/in2)

ls, bs, sf, λ, R, p, db, L, Sm and fy are as defined in 5C-3-4/7.7 above.

7.13 Deep Tank Double Bottom Girder (1999)

The net thickness of the double bottom girders forming boundaries of deep tanks, in addition to complying
with 5C-3-4/7.7, 5C-3-4/7.9 and 5C-3-4/7.11, is to be not less than t, obtained from the following equation:
t = 0.73s(k1p/f1)1/2 mm (in.)
where
s = spacing of longitudinals or vertical stiffeners
k1 = 0.342, for longitudinally stiffened plating

= 0.50k2, for vertically stiffened plating

k = (3.075(α)1/2 − 2.077)/(α + 0.272), (1 ≤ α < 2)
= 1.0, (α > 2)
α = aspect ratio of the panel (longer edge/shorter edge)
p = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), at the lower edge of each plate, as
specified in 5C-3-3/Table 3
Where the lower bottom tank is connected to the upper wing tank by trunks or double sides, the nominal
pressure, p, in load case “b” may be modified by the following equation:
p = pb − puo
pb is nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), at the lower edge of each plate, as defined in load case
“b” of 5C-3-3/Table 3 for other longitudinal bulkhead plating.
puo is as defined in 5C-3-4/9.1.
f1 = permissible bending stress in N/cm2 (kgf/cm2, lbf/in2)

= 1.2[1 − 0.4(z/B) − 0.52α1(SMRB/SMB)(y/yn)] Sm fy ≤ 0.70Sm fy

y = vertical distance, in m (ft), measured from the neutral axis of the hull girder transverse
section to the lower edge of each plate where the plating is longitudinally stiffened
= vertical distance, in m (ft), measured from the neutral axis of the hull girder transverse
section to the mid-depth of the double bottom height where the plating is vertically
stiffened
B = vessel’s breadth, in m (ft), as defined in 3-1-1/5
SMRB and SMB are as defined in 5C-3-4/7.3.1.

Sm, fy and α1 are as defined in 5C-3-4/7.5.

Z and yn are as defined in 5C-3-4/21.1.

7.15 Double Bottom Shear Capacity in Flooded Condition (1 July 1998)

In addition to the requirements of 5C-3-4/7.7, 5C-3-4/7.9 and 5C-3-4/7.11 for single or double side skin
bulk carriers intended to carry solid bulk cargoes having a density of 1.0 t/m3 (62.4 lb/ft3) or greater, the
shear strength of the floors and girders under loads caused by hold flooding are to meet the requirements in
Appendix 5C-3-A5c.

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Section 4 Initial Scantling Criteria 5C-3-4

FIGURE 3
Unsupported Span of Longitudinal

Trans Trans
a) Supported by transverses

F.B. F.B.

Trans Trans
b) Supported by transverses
and flat bar stiffeners

F.B. F.B.

d/2

Trans Trans

c) Supported by transverses,
flat bar stiffeners
and brackets

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Section 4 Initial Scantling Criteria 5C-3-4

FIGURE 4
Effective Breadth of Plating be

Longitudinal

Mx
M

c l c lo
For bending For bending
at ends at midspan s = spacing of longitudinals

a) For bending at midspan

clo/s 1.5 2 2.5 3 3.5 4 4.5 and greater

be/s 0.58 0.73 0.83 0.90 0.95 0.98 1.0

b) For bending at ends [be/s = (0.124cl/s – 0.062)1/2]

cl/s 1 1.5 2 2.5 3 3.5 4.0

be/s 0.25 0.35 0.43 0.5 0.55 0.6 0.67

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-3-4

FIGURE 5
Definition of ls and bs

ls

bs

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-3-4

9 Side Shell Plating and Longitudinals

9.1 Side Shell Plating (2001)

The net thickness of the side shell plating, in addition to complying with 5C-3-4/5.3, is to be not less than
t1, t2 and t3, obtained from the following equations for the midship 0.4L:

t1 = 0.73s(k1p/f1)1/2 mm (in.)

t2 = 0.73s(k2p/f2)1/2 mm (in.)
t3 = cs(Sm fy /E)1/2 mm (in.)
where
s = spacing of side longitudinals/frames, in mm (in.)
k1 = 0.342
k2 = 0.50

p = nominal pressure at the upper turn of bilge, in N/cm2 (kgf/cm2, lbf/in2), as specified in
5C-3-3/Table 3
Where upper and lower wing tanks are connected by trunks or double sides, the nominal pressure in load
case “a” may be modified by the following equation:
p = pa − puo

puo = 0.23γ(hlwtbwttan φe tan θe)1/3 where lwt ≥ 0.2L

= 0 where lwt ≤ 0.1L

Linear interpolation is to be used for intermediate values of lwt.

However, the nominal pressure at the upper turn of bilge may be taken as if the upper and lower wing
tanks were not connected, for calculation of the required thickness of side shell in way of the upper wing
tank. pa is nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), as defined in load case “a” at the upper turn of
bilge in 5C-3-3/Table 3 for side shell plating.
bwt = breadth at tank top of upper wing tank, in m (ft)

φe = effective pitch amplitude, as defined in 5C-3-3/5.7.3 with Cφ = 0.7

θe = effective roll amplitude, as defined in 5C-3-3/5.7.3 with Cθ = 0.7

L is vessel length, as defined in 3-1-1/3.1.
γ, h and lwt are as defined in 5C-3-4/7.3.1.

f1 = permissible bending stress, in the longitudinal direction, in N/cm2 (kgf/cm2, lbf/in2)

= [0.80 − 0.50 α1 (SMRB /SMB)(y/yb)] Sm fy , ≤ 0.40Sm fy , where SMB /SMRB is not to be
taken more than 1.4, below the neutral axis
= 0.40 Sm fy , above neutral axis
f2 = permissible bending stress, in the vertical direction, in N/cm2 (kgf/cm2, lbf/in2)
= 0.80 Sm fy

α1 = Sm1fy1/Sm fy
Sm = strength reduction factor, obtained from 5C-3-4/7.3.1 for the steel grade of the side
shell plating

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Section 4 Initial Scantling Criteria 5C-3-4

Sm1 = strength reduction factor, obtained from 5C-3-4/7.3.1 for the steel grade of the bottom
flange of the hull girder
fy = minimum specified yield point of the side shell material, in N/cm2 (kgf/cm2, lbf/in2)
fy1 = minimum specified yield point of the bottom flange material of the hull girder, in
N/cm2 (kgf/cm2, lbf/in2)
yb = vertical distance, in m (ft), measured from the upper turn of bilge to the neutral axis
of the section
c = 0.7N2 − 0.2, not to be less than 0.4Q1/2
N = Rd (Q/Qd)1/2 for the sheer strake
= Rd [(Q/Qd)(y/yn)]1/2 for other locations above neutral axis
1/2
= Rb [(Q/Qb)(y/yn)] for locations below neutral axis
Rd = (SMRDS /SMD)1/2
y = vertical distance, in m (ft), measured from the neutral axis of the hull girder transverse
section to the lower edge (upper edge) of the side shell strake, when the strake under
consideration is below (above) the neutral axis for N.
= vertical distance, in m(ft), measured from the neutral axis of the hull girder transverse
section to the lower edge of the side shell strake under consideration for f1.
SMRDS = reference net hull girder section modulus for sagging bending moment based on the
material factor of the deck flange of the hull girder in cm2-m (in2-ft)
= 0.9SMS
SMS = required gross hull girder section modulus at the location under consideration in
accordance with 3-2-1/3.7.1 and 3-2-1/5.5 for sagging total bending moment based
on the material factor of the deck flange of the hull girder in cm2-m (in2-ft)
Q, Qd = material conversion factor in 5C-3-4/5.1 for the side shell plating under consideration
and the deck flange of the hull girder, respectively.
yn = vertical distance, in m (ft), measured from the bottom (deck) to the neutral axis of the
section, when the strake under consideration is below (above) the neutral axis.
SMRB, SMB, Rb, Qb and E are as defined in 5C-3-4/7.3.1.
SMD is as defined in 5C-3-4/9.3.
The net thickness, t3, may be determined based on Sm and fy of the hull girder strength material required at
the location under consideration.
The side shell is to be longitudinally framed in the lower and upper wing tanks, except the upper part of
lower wing tank and the lower part of upper wing tank where the limited access makes this impractical.
These parts of the side shell may be transversely framed with efficient brackets arranged in line with the
side frames, provided the net thickness of the side shell plating in this area is not less than that of the
adjacent longitudinally framed shell and is also not less than t4, obtained from the following equation:

t4 = 0.73sk(k2 p/f)1/2 mm (in.)

where
s = spacing of side transverse brackets, in mm (in.)

k = (3.075 α − 2.077)/(α + 0.272) (1 ≤ α ≤ 2)

= 1.0 (α > 2)
k2 = 0.5

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Section 4 Initial Scantling Criteria 5C-3-4

α = aspect ratio of the panel (longer edge/shorter edge)

p = nominal pressure at the side shell under consideration, in N/cm2 (kgf/cm2, lbf/in2), as
specified in 5C-3-3/Table 3, but need not be greater than that at the upper turn of bilge
In the upper wing tank and lower wing tank which is connected to the upper wing tank by trunks or double
sides, the nominal pressure, p, in load case “a” may be modified by the following equation:
p = pa – puo
In no case is p to be taken less than 2.06 N/cm2 (0.21 kgf/cm2, 2.987 lbf/in2).
pa is nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), as defined in load case “a” at the lower edge of each
plate in 5C-3-3/Table 3 for side shell plating.
puo is as defined above.
f = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= 1.1 [0.80 − 0.50 α1 (SMRB/SMB)(y/yb)] Sm fy ≤ 0.60Sm fy , where SMB/SMRB is not to be
taken more than 1.4 below neutral axis
= 0.60 Sm fy , above neutral axis
All other parameters are as defined above.
For vessels intended to carry highly corrosive cargoes, additional corrosion margins are recommended for
the side shell plating between the upper and the lower wing tanks.
The net thickness of the side shell plating, where transversely framed between the upper and lower wing
tanks, is not to be less than t4, as specified above, with the nominal pressure calculated at the top of the
lower wing tank. The thickness is also not to be less than that of the adjacent side shell. Where upper and
lower wing tanks are connected by trunk, the required thickness of the adjacent side shell may be
calculated for this purpose as if the upper and lower wing tanks were not connected.
Where a cargo hold is intended to be used for the carriage of water ballast or liquid cargoes, the net
thickness of the side shell plating in the hold between the upper and lower wing tanks is also not to be
taken less than t5, obtained from the following equation.
t5 = 0.73s(kp/f)1/2 mm (in.)
where
s = spacing of side frames, in mm (in.)
k = 0.5
p = nominal pressure at the top of the lower wing tank, in N/cm2 (kgf/cm2, lbf/in2), as
specified in 5C-3-3/Table 3 for side structural members (ballast or liquid cargo holds)
f = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.75 Sm fy
In no case is the net thickness of shell plating in way of the cargo holds the side of which is bounded only
by side shell to be less than t6, given by the equation below:
t6 = (L)1/2 − 1.5 mm t6 = 0.02175 (L)1/2 − 0.06 in.
L = length of the vessel, as defined in 3-1-1/3.1, in m (ft)
The minimum width of the sheerstrake for the midship 0.4L is to be obtained from the following equations:
b = 5L + 800 mm for L ≤ 200 m
= 0.06L + 31.5 in. for L ≤ 656 ft
b = 1800 mm for 200 < L ≤ 500 m
= 70.87 in. for 656 < L ≤ 1640 ft

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Section 4 Initial Scantling Criteria 5C-3-4

where
L = length of the vessel, as defined in 3-1-1/3.1, in m (ft)
b = width of the sheer strake, in mm (in.)
The thickness of the sheer strake is to be increased 25% in way of breaks of superstructures, but this
increase need not exceed 6.5 mm (0.26 in.).
The thickness of a radiused gunwale is not to be less than that of the adjacent side shell or deck plating,
whichever is greater. When a radiused gunwale is fitted, the requirement for the minimum width of sheer
strake need not be considered applicable.

9.3 Side Longitudinals (1999)

The net section modulus of each side longitudinal, in association with the effective plating to which it is
attached, is to be not less than obtained from the following equation:
SM = M/fb cm3 (in3)

M = 1000 psl2/k N-cm (kgf-cm, lbf-in)

where
k = 12 (12, 83.33)
p = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), at the side longitudinal considered, as
specified in 5C-3-3/Table 3
In the upper wing tank and lower wing tank which is connected to the upper wing tank by trunks or double
sides, the nominal pressure, p, in load case “a” may be modified by the following equation:
p = pa – puo

In no case is p to be taken less than 2.06 N/cm2 (0.21 kgf/cm2, 2.987 lbf/in2).
pa is nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), as defined in load case “a” at the lower edge of each
plate in 5C-3-3/Table 3 for side shell plating.
puo is as defined in 5C-3-4/9.1.

s and l are as defined in 5C-3-4/7.5.

fb = permissible bending stresses, in N/cm2 (kgf/cm2, lbf/in2)
= 1.4 [0.80 − 0.52 α1 (SMRB/SMB) (y/yn)] Sm fy ≤ 0.80Sm fy , for side longitudinals below
neutral axis
= 2.2 [0.80 − 0.52 α2 (SMRD/SMD) (y/yn)] Sm fy ≤ 0.80Sm fy , for side longitudinals above
neutral axis
α2 = Sm2 fy2/Sm fy

Sm, fy and α1 are as defined in 5C-3-4/7.5.

Sm2 = strength reduction factor for the steel grade of the top flange material of the hull
girder, obtained from 5C-3-4/7.3.1.
fy2 = minimum specified yield point of the top flange material of the hull girder, in N/cm2
(kgf/cm2, lbf/in2)
SMRD = reference net hull girder section modulus based on the material factor of the top
flange of the hull girder, in cm2-m (in2-ft)
= 0.9 SM

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Section 4 Initial Scantling Criteria 5C-3-4

SM = required gross hull girder section modulus at the location under consideration in
accordance with 3-2-1/3.7 and 3-2-1/5.5 based on the material factor of the deck
flange of the hull girder, in cm2-m (in2-ft)
SMD = design (actual) net hull girder section modulus to the deck at the location under
consideration, in cm2-m (in2-ft)
SMRB and SMB are as defined in 5C-3-4/7.3.1.
y = vertical distance, in m (ft), measured from the neutral axis of the section to the
longitudinal under consideration at its connection to the associated plate
yn = vertical distance, in m (ft), measured from the deck (bottom) to the neutral axis of the
section, when the longitudinal under consideration is above (below) the neutral axis.
The effective breadth of plating, be, is as defined in 5C-3-4/7.5.
The net moment of inertia of each side longitudinal within the region of 0.1D from the deck at side, in
association with the effective plating (bwL·tn), is to be not less than obtained from the following equation:

io = k Ae l2 fy /E cm4 (in4)
where
k = 1220 (1220, 17.57)
Ae = net sectional area of the longitudinal with the associated effective plating (bwL·tn), in
cm2 (in2)
bwL = ce s

ce = 2.25/β − 1.25/β2 for β ≥ 1.25

= 1.0 for β < 1.25

β = (fy/E) 1/2
s/tn
tn = net thickness of the plate, in mm (in.)
D = depth of the vessel, in m (ft), as defined in 3-1-1/7
l, s and fy are as defined in 5C-3-4/7.5.
E is as defined in 5C-3-4/7.3.1.

11 Side Frames and Supporting Structures (1 July 1998)

11.1 General (2003)

The hold frames of the configuration shown in 5C-3-4/Figure 6, and their supporting structures are to be
designed in compliance with Section 3-2-5, except when otherwise specified in Part 5C, Chapter 3, to
provide sufficient transverse strength for the hull girder and proper load transmission between the upper
and lower wing tank structures. In addition to the section modulus and the minimum thickness requirements
specified below, the stiffness of the structural elements and the design of end brackets are to be in compliance
with the buckling and fatigue criteria given in 5C-3-5/5. For double side skin construction, transverse side
frames in association with vertical diaphragms and side stringers are to be provided in ballast tanks or void
spaces. The scantlings of transverse side frames in double hull side tanks or void spaces are to comply with
5C-3-4/11.3. Where side longitudinals are provided in lieu of transverse side frames in side ballast tanks or
void spaces, the scantlings of the longitudinals are to comply with 5C-3-4/9.3. Vertical diaphragms are to
be properly arranged in line with the transverse webs in the topside tank or lower wing tank.

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-3-4

11.3 Frame Section Modulus (2003)

The net section modulus of the hold frame in association with effective shell plating to which it is attached
is not to be less than obtained from the following equations, whichever is greater.
SMF = M/fb in cm3 (in3)

M = 1000 c1p1sl2/k1 or

= 1000 c1p2sl2/k2 + k3wb N-cm (kgf-cm, lbf-in)

= 1000 c1p1sl2/k1 N-cm (kgf-cm, lbf-in) for side frames in double hull
side tanks or void spaces
where
k1 = 12 (12, 83.33)
k2 = 16 (16, 111.11)
k3 = 5 (5, 0.6)
c1 = 1 − 4(d/l) ≥ 0.65
= 1 + γl/10p1 for side frames in double hull side tanks or void spaces
γ = specific weight of sea water, 1.005 N/cm2-m (0.1025 kgf/cm2-m, 0.444 lbf/in2-ft)
p1, p2 = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), at the middle of the unsupported span
of the hold frame (dry cargo holds), as specified in 5C-3-3/Table 3 case “a” and case
“b”, respectively
s = spacing of hold frames, in mm (in.)
d = depth of hold frames, in m (ft)
l = unsupported span of the hold frame, in m (ft) (see 5C-3-4/Figure 6)
w = weight of the ballast water in upper wing tank per frame spacing for one side (port or
starboard), in N (kgf, lbf), and may be approximated as follows:
= k4(h1 + h2)bs
k4 = 5.026 (0.5125, 0.032)
h1, h2, b = dimensions of the upper wing tank, in m (ft), as shown in 5C-3-4/Figure 6
fb = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= Sm fy − F/A
= 0.8 Sm fy for side frames in double hull side tanks or void spaces
F = axial force, in N (kgf, lbf)
= (0.5 + 2lH /bw)Bspb k5
k5 = 1 (1, 1.2)
lH = length of the cargo hold, in m (ft)
bw = breadth of the double bottom structure, in m (ft). For vessels having lower wing tanks
with sloping tops, making an angle of about 45 degrees with the horizontal, the
breadth may be measured between the midpoints of the sloping plating
B = breadth of the vessel, in m (ft), as defined in 3-1-1/5
pb = corresponding net nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), of the double bottom
structure at its centerline (5C-3-3/Table 3, item 4, case “a” and case “b” for p1 and p2
above, respectively)
A = net sectional area of the frame and the associated effective plating (stn), in cm2 (in2)

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Section 4 Initial Scantling Criteria 5C-3-4

Sm and fy are as defined in 5C-3-4/7.3.1.

The effective breadth of plating, be, is as defined in 5C-3-4/7.5.
Where a cargo hold is also intended to be a water ballast or liquid cargo tank, the net section modulus of
the hold frame is also not to be less than obtained from the following equation:
SMF = M/fb in cm3 (in3)

M = 1000c1p3sl2/k N-cm (kgf-cm, lbf-in)

where
k = 12 (12, 83.33)
p3 = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), at the middle of the unsupported span
of hold frames, as specified in 5C-3-3/Table 3 for hold frame (ballast or liquid cargo
holds)
pb = corresponding net nominal pressure, N/cm2 (kgf/cm2, lbf/in2) of the double bottom
structure at B/4 off its centerline [5C-3-3/Table 3 for hold frame (ballast or liquid
cargo holds)]
All other parameters are as defined above.

11.5 Frame Sections

In vessels of 190 m (623 ft) or more in length, frames are to be fabricated symmetrical sections with
integral upper and lower brackets. Their brackets are to be soft toed. The side frame flange is to be curved
(not knuckled) at the transition to integral brackets. The radius of curvature is not to be less than r, in mm
(in.), given by:
0.4 ⋅ b 2f
r=
tf +c

where bf and tf are the flange width and net flange thickness of the brackets, respectively, in mm (in.).
c = 1.5 mm (0.06 in.). The end of the flange is to be sniped.
In vessels less than 190 m (623 ft) in length, frames of ordinary strength steel may be asymmetric sections
(fabricated or rolled) and fitted with separate brackets. The face plate or flange of the bracket is to be
sniped at both ends. Brackets are to be soft toed.
For vessels of all lengths, the web depth to thickness ratio of frames is to comply with the proportion limits
given in 5C-3-A2/11.9. The ratio of outstanding flange breadth to gross thickness is not to exceed 10 Q ,
where Q is as defined in 3-2-1/5.5.

11.7 Brackets
11.7.1 Section Modulus
The net section modulus of the lower and upper brackets at the top of the lower wing tank and the
bottom of the upper wing tank, as indicated in 5C-3-4/Figure 6, in association with the effective
shell plating to which they are attached, is not to be less than obtained from the following equation:

SME = c2 h32 SMF /(c1l2) in cm3 (in3)

where
c2 = 1.2 for upper bracket
= 1.1 for lower bracket
h3 = vertical distance, in m (ft), between the top of lower wing tank and the
bottom of upper wing tank (see 5C-3-4/Figure 6)
SMF = required net section modulus of the hold frame in 5C-3-4/11.3

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Section 4 Initial Scantling Criteria 5C-3-4

c1 and l are as defined in 5C-3-4/11.3.

In no case is SME to be less than 2.0(SMF).
When the section modulus is calculated in way of the brackets, any bracket flange or face plate
which is sniped at both ends may be considered effective for this purpose only if the location as
indicated in 5C-3-4/Figure 6 is clear of the snipe and lies within the middle two-thirds of the
flange length.
11.7.2 Arm Lengths
Integral or separate frame brackets are to extend at least for a length of 0.125h3 onto the frame and
the depth of the bracket plus frame, measured at the heels of the frame, is generally to be at least
1.5 times that of the frame. Where the hull form renders this impracticable, equivalent strength in
shear and bending is to be provided. The brackets are to be arranged with “soft” toes. See
5C-3-4/Figure 7 and 5C-3-4/Figure 8).
11.7.3 Minimum Thickness
The net thickness of the brackets and the web portions of the frames is not to be less than obtained
from the following equation:
tn = 0.03L + 5.5 mm

= (0.036L + 21.7)10-2 in.

but need not to be greater than 11.5 mm (0.45 in.)
where
L = length of vessel, in m (ft), as defined in 3-1-1/3.1
The net thickness of the upper bracket is to be not less than tn above or the proposed net thickness
of web of the frame being supported, whichever is greater.
The net thickness of the lower bracket is to be not less than tn above or the proposed net thickness
of web of the frame being supported reduced by 2.0 mm (0.08 in.), whichever is greater.
11.7.4 Supporting Bracket
Brackets are to be fitted in the lower and upper wing tanks, in line with every side frame.

11.9 Longitudinals at the Toe of Brackets

The section modulus of side longitudinals and sloping bulkhead longitudinals at the toes of brackets is to
be determined based on 5C-3-4/9.3 and 5C-3-4/21.11 with the unsupported span, l, measured between
transverses and spacing, s, taken equal to dimension “b”, as shown in 5C-3-4/Figure 8.

13 Side Transverses/Web Frames and Transverse Webs in Lower and

Upper Wing Tanks (1996)

13.1 General (1997)

The main supporting members such as the transverse webs and girders are to be arranged and designed
with sufficient stiffness to provide support to the vessel’s hull structure. In general, deep beams, web
frames and bottom floors are to be arranged in one plane to form continuous transverse rings. Deck girders
and continuous hatch coamings, where fitted, are to be extended throughout the cargo hold spaces and are
to be effectively supported at the transverse bulkheads.
Generous transitions are to be provided at the intersections of the main supporting members to provide for
smooth transmission of loads and to minimize stress concentrations. Abrupt changes in sectional properties
and sharp re-entrant corners are to be avoided. In general, stool structures, where fitted, are to have sloping
bulkheads on both sides.

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-3-4

The net section modulus and sectional area of the main supporting members required by this Chapter apply
to those parts of the member clear of the end brackets. They are considered as the requirements of initial
scantlings for transverses in lower and upper wing tanks, and may be reduced, provided the strength of the
resultant design is verified with the subsequent total strength assessment in Section 5C-3-5. However, in
no case should they be taken less than 85% of those determined from this section. (See also 5C-3-5/9.9.)
The structural properties of the main supporting members and end brackets are to comply with failure
criteria specified in 5C-3-5/3, 5C-3-5/5 and 5C-3-5/7.
The required section modulus of the main supporting members in association with the effective plating to
which they are attached is to be determined as specified in 3-1-2/13.

13.3 Transverses in Lower Wing Tank

13.3.1 Section Modulus
The net section modulus of the transverses in the lower wing tank in association with the effective
plating is not to be less than obtained from the following equation:
SM = M/fb cm3 (in3)
M = M1 + M2

M1 = 1000ps l 2b /k1 N-cm (kgf-cm, lbf-in)

M2 = 0 for sloping bulkhead transverse
= 0.5 MsL for side transverse
= M1s for bottom transverse
where
k1 = 0.12 (0.12, 0.446)
MsL = bending moment for sloping bulkhead transverse, in N-cm (kgf-cm, lbf-in)
M1s = bending moment M1 for side transverse, in N-cm (kgf-cm, lbf-in)
p = nominal pressure, in kN/m2 (tf/m2, Ltf/ft2), at the midspan of lb of the
transverse under consideration, as specified in 5C-3-3/Table 3
s = spacing of the webs in the lower wing tank, in m (ft)
lb = span of the transverse under consideration, in m (ft)

fb = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)

= 0.7 Sm fy

For the calculation of the section modulus, lb is to be taken not less than c1lo.
where
lo = bSL for sloping bulkhead transverse
= bS for side transverse
= bB for bottom transverse
c1 = 0.4 for sloping bulkhead transverse and side transverse
= 0.5 for bottom transverse
bSL, bS and bB are as shown in 5C-3-4/Figure 9.
The bending moment M for the bottom transverse is not to be less than 80% of the bending
moment M for the sloping bulkhead transverse.

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Section 4 Initial Scantling Criteria 5C-3-4

13.3.2 Web Sectional Area

The net sectional area of the web of the transverses in the lower wing tank is not to be less than
obtained from the following equation:
A = Fs /fs cm2 (in2)

Fs = 1000k2 ps(0.5l − he) N (kgf, lbf)

where
k2 = 1 (1, 2.24)
l = span, in m (ft), of the transverse under consideration as shown in
5C-3-4/Figure 9
he = length, in m (ft), of the end bracket as shown in 5C-3-4/Figure 9
For the calculation of the web sectional area, l is to be taken not less than c1lo.
c1, lo, p and s are as defined in 5C-3-4/13.3.1 above.
fs = permissible shear stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.5 Sm fy
13.3.3 Depth of Transverses in Lower Wing Tank (1997)
The depth of the transverses in the lower wing tank is not to be less than c2lo
where
c2 = 0.12 for sloping bulkhead and side transverses
= 0.16 for the bottom transverse
lo is as defined in 5C-3-4/13.3.1 above.
In general, the depth of the transverse is to be not less than 2.5 times the depth of the slots.

13.5 Transverses in Upper Wing Tank in Way of Dry Cargo Holds

13.5.1 Section Modulus
The net section modulus of the transverses in the upper wing tank in association with the effective
plating is not to be less than obtained from the following equation:
SM = M/fb cm3 (in3)
M = c1(M1 + M2) for deck and sloping bulkhead transverses
M = 2000k1c1pssbss(b)2/(b1 + 0.5ls) N-cm (kgf-cm, lbf-in) for side transverse
2
M1 = 1000c2 pss(ls) /k2 N-cm (kgf-cm, lbf-in)
M2 = 1000c3 pd s(ld)2/k2 N-cm (kgf-cm, lbf-in)
where
k1 = 1 (1, 0.269)
k2 = 0.12 (0.12, 0.446)
c1 = 1.0 for deck, sloping bulkhead and side transverses in the upper wing
tank without longitudinal bulkhead
= 0.7 for deck and side transverses in the upper wing tank with
longitudinal bulkhead
= 0.65 for sloping bulkhead transverse in the upper wing tank with
longitudinal bulkhead

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Section 4 Initial Scantling Criteria 5C-3-4

c2 = 1.5/(1 + β) for deck transverse

= 1.0 for sloping bulkhead transverse
c2 is not to be taken less than 0.5 for deck transverse.
c3 = 1.5β/(1 + β) for deck transverse
= 0.50 for sloping bulkhead transverse
c3 is not to be taken less than 0.8 for deck transverse.
β = (ld /ls)(is /id)
id , is = moments of inertia of the deck transverse and the sloping bulkhead transverse
with effective plating, clear of end brackets
ps = nominal pressure, in kN/m2 (tf/m2, Ltf/ft2) at the midspan of lb of the sloping
bulkhead transverse, as specified in 5C-3-3/Table 3
pd = nominal pressure, in kN/m2 (tf/m2, Ltf/ft2) at the midspan of lb of the deck
transverse, as specified in 5C-3-3/Table 3
s = spacing of the webs in the upper wing tank, in m (ft)
ld, ls = span lb of the deck and sloping bulkhead transverses under consideration, in
m (ft)
To obtain M for the deck and sloping bulkhead transverses, span ld is not to be taken less than
0.4b and span lb is not to be taken less than 0.4bsu.
b, bsu = widths of the upper wing tank, in m (ft), as shown in 5C-3-4/Figure 9
b1 = distance from the longitudinal hatch side girder to the side of the opening in
the web, in m (ft), as shown in 5C-3-4/Figure 9
bss = height of the upper wing tank, in m (ft), as shown in 5C-3-4/Figure 9
fb = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.85 Sm fy
13.5.2 Web Sectional Area
The net sectional area of the web of the transverses in the upper wing tank is not to be less than
obtained from the following equation.
A =F/fs cm2 (in2)
F = 1000k3c1c2c3 pss(b1 + ls)2/(b1 + 0.5ls) N (kgf, lbf) for deck and side
transverses
F = 1000c2c3(F1 + F2) N (kgf, lbf) for sloping bulkhead
transverses
where
F1 = k3 ps s(0.5l − he)
F2 = 0.8k3 pss b12 /(b1 + 0.5ls)
k3 = 1 (1, 2.24)
c1 = 0.38 for deck transverse
= 0.16 for side transverse
c2 = Ad/(Ad + As) for deck transverse
= As/(Ad + As) for sloping bulkhead transverse
= 1.0 for side transverse
c2 is not to be taken less than 0.42

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-3-4

Ad, As = web sectional areas of the deck and sloping bulkhead transverses, clear of the
end brackets
c3 = 1.0 for transverses in upper wing tank without longitudinal bulkhead
= 0.7 for transverses in upper wing tank with longitudinal bulkhead
fs = permissible shear stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.5 Sm fy

l = span, in m (ft), of sloping bulkhead transverse, as shown in 5C-3-4/Figure 9

he = length, in m (ft), of the lower end bracket of the sloping bulkhead transverse,
as shown in 5C-3-4/Figure 9
ps, s, b, b1 and l are as defined in 5C-3-4/13.5.1 above.

13.5.3 Depth of Transverses in Upper Wing Tank

The depth of the transverses in the upper wing tank is not to be less than as specified below,
respectively.
0.15bss for side transverse
0.085b for deck transverse
0.085bsu for sloping bulkhead transverse
where
b, bss and bsu are as shown in 5C-3-4/Figure 9.
In general, the depth of the transverse is to be not less than 2.5 times the depth of the slots.

13.7 Transverses in Upper Wing Tank in Way of Ballast or Liquid Cargo Holds
Where a cargo hold is intended to be used for the carriage of water ballast or liquid cargoes, the net section
modulus and the web sectional area of the transverses are also not to be less than obtained from the
following requirements, respectively.
13.7.1 Section Modulus
The net section modulus of the side, deck and sloping bulkhead transverses in the upper wing tank
in association with the effective plating is not to be less than obtained from the following
equation:
SM = M/fb cm3 (in3)
M = 15k1c1psbsu bss(2B − b)/(B − b + 0.5ls + b1) N-cm (kgf-cm, lbf-in)
for side transverse
M = c1(M1 + M2) for deck and sloping bulkhead
transverse
M1 = 1000c2 ps(ls)2/k2 N-cm (kgf-cm, lbf-in)

M2 = 1000k1c3c4 psb1lb (2B − 2b + b1)/(B − b + 0.5ls + b1) N-cm (kgf-cm, lbf-in)

where
k1 = 100 (100, 26.9)
k2 = 0.12 (0.12, 0.446)

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Section 4 Initial Scantling Criteria 5C-3-4

c1 = 1.0 for deck, sloping bulkhead and side transverses in upper wing tank
without longitudinal bulkhead
= 0.50 for sloping bulkhead transverse in upper wing tank with longitudinal
bulkhead
= 0.70 for deck and side transverses in upper wing tank with longitudinal
bulkhead
c2 = 1.0 for sloping bulkhead transverse

= 1.5/(1 + β) for deck transverse

c2 is not to be taken less than 0.54 for the deck transverse.
c3 = 0.095 for sloping bulkhead transverse
= 0.035 for deck transverse
c4 = 0.233β + 0.034 for sloping bulkhead transverse, if β ≤ 2.0

= 0.7β − 0.9 for sloping bulkhead transverse if β > 2.0

c4 is not to be taken less than 0.15 and need not be greater than 1.0 for sloping bulkhead transverse.

c4 = 1.343 − 0.0714β for deck transverse

c4 is not to be taken less than 1.0 for deck transverse.

β is as defined in 5C-3-4/13.5.1.
p = nominal pressure, in kN/m2 (tf/m2, Ltf/ft2), at the midspan of lb of the
sloping bulkhead transverse, as specified in 5C-3-3/Table 3
lb = span of the transverse under consideration, in m (ft), as shown in
5C-3-4/Figure 9
ls = span of lb of the sloping bulkhead transverse, in m (ft), as shown in
5C-3-4/Figure 9
To obtain moment M1, span ls is to be taken not less than 0.33bsu.
s, B, b, b1, bsu and bss are as defined in 5C-3-4/13.5.1.

fb = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)

= 0.85 Sm fy

13.7.2 Web Sectional Area

The net sectional area of the web of the transverses in the upper wing tank is not to be less than
obtained from the following equation:
A = F/fs cm2 (in2)
F = 1000k3c1c2c3 psbsu(2B − b)/(B − b + 0.5ls + b1), N (kgf, lbf) for deck and side
transverses
= 1000c1c3(F1 + F2) N (kgf, lbf) for sloping
bulkhead transverse
F1 = k3 2.38ps(0.5l − he) N (kgf, lbf)

F2 = k3 0.117psb1(2B − 2b + b1)/(B − b + 0.5ls + b1) N (kgf, lbf)

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Section 4 Initial Scantling Criteria 5C-3-4

where
k3 = 1.0 (1.0, 2.24)
c2 = 0.16 for deck transverse
= 0.105 for side transverse
c3 = Ad/(Ad + As) for deck transverse
= As/(Ad + As) for sloping bulkhead transverse
= 1.0 for side transverse
Ad, As, l and he are as defined in 5C-3-4/13.5.2.

p, ls and c1 are as defined in 5C-3-4/13.7.1.

B, s, b and b1 are as defined in 5C-3-4/13.5.1.

l = span, in m (ft), of sloping bulkhead transverse, as shown in 5C-3-4/Figure 9

he = length, in m (ft), of the lower end bracket of the sloping bulkhead transverse,
as shown in 5C-3-4/Figure 9
fs = permissible shear stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.5 Sm fy

13.7.3 Depth of Transverses in Upper Wing Tank

The depth of transverses is to be as specified in 5C-3-4/13.5.3.

13.9 Minimum Thickness for Web Portion of Main Supporting Members

The net thickness of the web of the main supporting members is not to be less than 9.5 mm (0.374 in.)

13.11 Vertical Diaphragms and Side Stringers in Double Hull Side Tanks or Void Spaces
(2003)
The net thickness of vertical diaphragms and side stringers is not to be less than 9.5 mm (0.374 in.).
13.11.1 Vertical Diaphragms
The net section modulus of vertical diaphragms in association with effective shell/inner skin
plating to which they are attached is, in general, not to be less than obtained from the following.
SMDP = M/fb in cm3 (in3)
where
M = 1000 c1psl2/k2 + k3wb N-cm (kgf-cm, lbf-in)
p = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), at the middle of the unsupported
span, l, as specified in 5C-3-3/Table 3B case “a” and case “b”, respectively
s = spacing of vertical diaphragms in mm (in.)
l = unsupported span between the top side tank and the lower wing tank
w = weight of the ballast water in upper wing tank per spacing of vertical
diaphragm for one side (port or starboard), in N (kgf, lbf)
fb = 0.85Smfy
c1, k2, k3, b, Sm and fy are defined in 5C-3-4/11.3.

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Section 4 Initial Scantling Criteria 5C-3-4

Where the cargo hold is intended to be used for the carriage of water ballast or liquid cargoes, the
net section modulus of the diaphragms is, in general, not to be less than obtained from the following
equation:
SMDP = M/fb in cm3 (in3)

M = 1000 c1psl2/k2 N-cm (kgf-cm, lbf-in)

where
p = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), at the middle of the unsupported
span, l, as specified in 5C-3-3/Table 3B for vertical diaphragms (ballast or
liquid cargo holds)
All other parameters are as defined above.
13.11.2 Side Stringers
The net thickness of a side stringer is also to be not less than t, obtained from the following equation:
t = cs(Sm fy /E)1/2 mm (in.)
where
c = 0.7N2 − 0.2, not to be less than 0.33
s = spacing of longitudinals, in mm (in.)
Sm = strength reduction factor, obtained from 5C-3-4/7.3.1, for the steel grade of
the stringer
fy = minimum specified yield point of the stringer material, in N/cm2 (kgf/cm2,
lbf/in2)
N = Rd[(Q/Qd)(y/yn)]1/2 for stringers above neutral axis

= Rb[(Q/Qb)(y/yn)]1/2 for stringers below neutral axis

Q = material conversion factor in 5C-3-4/5.1 for the side stringer under
consideration
y = vertical distance, in m (ft), measured from the neutral axis of the hull girder
transverse section to the side stringer under consideration
E, Rb and Qb are as defined in 5C-3-4/7.3.1. Rd, Qd and yn are as defined in 5C-3-4/9.1.
The net thickness, t, may be determined based on Sm and fy of the hull girder strength material
required at the location under consideration.
13.11.3 Grillage Analysis
The net scantlings of vertical diaphragms and associated side stringers may be determined based
on a grillage analysis, provided that the calculated stresses for the nominal pressure as specified in
5C-3-3/Table 3B for vertical diaphragms and side stringers do not exceed the following permissible
values:
Permissible Bending Stress, fb: 0.85Smfy for vertical diaphragms
0.75Smfy for horizontal stringers
Permissible Shear Stress, fs: 0.50Smfy for vertical diaphragms
0.45Smfy for horizontal stringers

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-3-4

FIGURE 6
Definitions of Parameters for Hold Frame (2003)
b
Double Skin Construction

h1

Upper Wing Tank

h2

SME for Upper Bracket

in 5C-3-4/11.7.1
d/2

Unsupported Span l for each location

Unsupported Span l

d
h3

d/2
SME for Lower Bracket
in 5C-3-4/11.7.1

Lower Wing Tank

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-3-4

FIGURE 7
(1 July 1998)
0.5d
(in general)

0.125h3

d
WEB HEIGHT

FIGURE 8
(1 July 1998)

SOFT TOE

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-3-4

FIGURE 9
Transverses in Wing Tanks Definition of Span
Upper wing tank

b b
b1 l b1 l
lb lb

he he

lb l lb l bss
he bss

lb l lb
l he
bsu bsu

Lower wing tank

bSL bSL

l l
lb bs lb
he he he bs
he lb l he lb l

lb lb
l l
bB bB

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-3-4

15 Deck Plating and Longitudinals/Beams

15.1 Main Deck Plating (1999)

The net thickness of the strength deck plating is to be not less than that needed to meet the hull girder
section modulus requirement in 3-2-1/3.7 and the buckling and ultimate strength requirements in 5C-3-5/5.
In addition, the net thickness of deck plating is to be not less than t1, t2 and t3, as specified below for the
midship 0.4L:
t1 = 0.73s(k1p/f1)1/2 mm (in.)

t2 = 0.73s(k2p/f2)1/2 mm (in.)
t3 = cs(Sm fy/E)1/2 mm (in.)
where
s = spacing of deck longitudinals, in mm (in.)
k1 = 0.342
k2 = 0.50
p = pn – puh

In no case is p to be taken less than 2.06 N/cm2 (0.21 kgf/cm2, 2.987 lbf/in2)
pn is nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), as defined in 5C-3-3/Table 3, for deck plating.
puh is as defined in 5C-3-4/7.3.1.
The net thickness, t3, may be determined based on Sm and fy of the hull girder strength material required at
the location under consideration.
f1 = permissible bending stress, in the longitudinal direction

= 0.15 Sm fy , in N/cm2 (kgf/cm2, lbf/in2)

f2 = permissible bending stress, in the transverse direction
= 0.80 Sm fy , in N/cm2 (kgf/cm2, lbf/in2)
c = 0.5 (0.6 + 0.0015L) for SI or MKS Units
= 0.5 (0.6 + 0.0046L) for U.S. Units
c is not to be taken less than 0.7N − 0.2 for vessels less than 267 m (876 ft) in length.
2

L = length of vessel, in m (ft), as defined in 3-1-1/3.1

N = Rd (Q/Qd)1/2

Rd = (SMRDS /SMD)1/2
Q = material conversion factor in 5C-3-4/5 for the deck plating
Sm, fy and E are as defined in 5C-3-4/7.3.1.
SMRDS and Qd are as defined in 5C-3-4/9.1.
SMD is as defined in 5C-3-4/9.3.

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Section 4 Initial Scantling Criteria 5C-3-4

15.3 Main Deck Longitudinals (1999)

The net section modulus of each deck longitudinal, in association with the effective plating to which it is
attached, is to be not less than obtained from the following equation:
SM = M/fb cm3 (in3)

M = 1000psl2/k N-cm (kgf-cm, lbf-in)

where
k = 12 (12, 83.33)
p = nominal deck pressure, in N/cm2 (kgf/cm2, lbf/in2), as specified in 5C-3-4/15.1
s, l are as defined in 5C-3-4/7.5
fb = permissible bending stresses, in N/cm2 (kgf/cm2, lbf/in2)

= (1.0 − 0.60α2SMRD/SMD)Sm fy

α2 = Sm2 fy2/Sm fy
Sm and fy are as defined in 5C-3-4/7.5.
Sm2 = strength reduction factor for the steel grade of the top flange material of the hull
girder, obtained from 5C-3-4/7.3.1
fy2 = minimum specified yield point of the top flange material of the hull girder, in N/cm2
(kgf/cm2, lbf/in2)
SMRD and SMD are as defined in 5C-3-4/9.3.
The effective breadth of plating, be, is as defined in 5C-3-47.5.
The net moment of inertia of each deck longitudinal in association with the effective plating (bwL·tn), is to
be not less than io, as specified in 5C-3-4/9.3.

15.5 Cross Deck Plating

The net thickness of the cross deck plating is to satisfy the buckling requirements in Section 5C-3-5 and is
not to be less than t1, t2 and t3, as obtained from the following equations:
t1 = 0.02L + 4.5 mm
= 0.00024L + 0.18 in.
t2 = s/90 mm (in.)
t3 = k1F/(wfs) mm (in.)
but not to be less than 8.5 mm (0.33 in.)
where
L = length of the vessel, as defined in 3-1-1/3.1, in m (ft)
s = spacing of deck beams, in mm (in.)
k1 = 0.1 (0.1, 0.083)
F = k2(1 + 0.74bo/w)TM(LH)2wn2/(DB3) N (kgf, lbf)
k2 = 24 (24, 53.76)
LH = length of the longest hold within the midship 0.4L, in m (ft)
TM = torsional moment, in kN-m (tf-m, Ltf-ft), as defined in 5C-3-3/5.3.3

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Section 4 Initial Scantling Criteria 5C-3-4

bo = width of the hatch opening, in m (ft)

w = width of the cross deck structure, in m (ft), as indicated in 5C-3-4/Figure 10
n = total number of holds
B = breadth of the vessel, as defined in 3-1-1/5, in m (ft)
D = depth of the vessel, as defined in 3-1-1/7.3, in m (ft)
fs = permissible shear stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.45 Sm fy

15.7 Cross Deck Beams

15.7.1 Section Modulus (1997)
The net section modulus of the deck beam inside the lines of hatch openings, in association with
the effective deck plating, is not to be less than obtained from the following equation.
SM = M/fb cm3 (in3)
M is equal to M1 or M2, whichever is larger.

M1 = 100c1ps bo2 /k N-cm (kgf-cm, lbf-in)

M2 = 100psl2/k N-cm (kgf-cm, lbf-in)

where
k = 12 (12, 0.536)
c1 = 1/(n + 1)2, not to be taken less than 0.02 and need not be greater than 0.05

p = nominal pressure, in kN/m2 (tf/m2, Ltf/ft2), as specified in 5C-3-3/Table 3 for

deck at centerline, not to be less than 20.6 kN/m2 (2.1 tf/m2, 0.192 Ltf/ft2)
s = spacing of the deck beams, in mm (in.)
bo = width of the hatch opening, in m (ft)

l = maximum unsupported span of the deck beam, in m (ft)

n = number of deck girders inside the lines of hatch openings
fb = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.4 Sm fy
The effective breadth of plating, be, is as defined in 5C-3-4/7.5.

15.7.2 Moment of Inertia

The net moment of inertia of the deck beam inside the lines of hatch openings, in association with
the effective plating (bwL·tn), is to be not less than that obtained from the following equation:

io = kAel2fy /E cm4 (in4)

where
k = 2440 (2440, 35.14)
Ae = net sectional area of the beam with the associated effective plating (bwL tn), in
cm2 (in2)
bwL = ces

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Section 4 Initial Scantling Criteria 5C-3-4

ce = 2.25/β − 1.25/β2 for β ≥ 1.25

= 1.0 for β < 1.25

β = (fy /E)1/2 s/tn
tn = net thickness of the plate, in mm (in.)

l = unsupported span of the beam, in m (ft)

s and fy are as defined in 5C-3-4/7.5.
E is as defined in 5C-3-4/7.3.1.

15.9 Stiffness of Cross Deck Structures (1996)

15.9.1 Minimum Sectional Area
The total net sectional area of the cross deck structure at vessel’s centerline, inside the lines of
hatch openings (see 5C-3-4/Figure 10), between two adjacent hatch openings is not to be less than
that obtained from the following equation:
A = F/fc cm2 (in2)
F = F1 + F2

F1 = kc(Q − 0.544P)B/D N (kgf, lbf)

F2 = kpDLH N (kgf, lbf)
where
k = 250 (250, 560)
Q = total cargo weight, in kN (tf, Ltf), with full cargo loads in the two adjacent
holds considered
P = 2LHBdγ, in kN (tf, Ltf)
γ = 10.05 (1.025, 0.0286), in kN/m3 (tf/m3, Ltf/ft3)
c = 0.312 − 0.0688LH /B if LH /B ≥ 0.9
= 0.3625 − 0.125 LH /B if LH /B < 0.9
LH = 0.5(LH1 + LH2)
LH1, LH2 = length of the adjacent holds, in m (ft)
B = breadth of the vessel, as defined in 3-1-1/5, in m (ft)
D = depth of the vessel, as defined in 3-1-1/7.3, in m (ft)
d = design draft of the vessel, as defined in 3-1-1/9, in m (ft)
p = 1.02k1C1, in kN/m2 (tf/m2, Ltf/ft2)
k1 = 9.8 (1.00, 0.0914)
C1 is as defined in 3-2-1/3.5.
fc = permissible compressive stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.7 Sm fy
The following items may be included in the calculation of the sectional area A:
• Deck plating and continuous beams
• Upper stool or box structure on top of bulkhead corrugation
• Hatch-end beams below the deck

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-3-4

15.9.2 Section Modulus

The total net section modulus of the cross deck structure at any section with respect to the vertical
axis (z axis shown in 5C-3-4/Figure 10) is not to be less than that obtained from the following equation:
SM = M/fb cm3 (in3)
M = Fb1 N-cm (kgf-cm, lbf-in)
where
F = shear force, in N (kgf, lbf), as defined in 5C-3-4/15.5
b1 = transverse distance, in cm (in.), from centerline of the vessel to the section of
the cross deck structure under consideration, as indicated in 5C-3-4/Figure 10,
b1 is not to be more than 0.5bo, where bo = width of hatch opening
fb = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.70 Sm fy
The items included in the calculation of the section modulus are as specified in 5C-3-4/15.9.1.

FIGURE 10
Cross Deck Structure

Transverse Bulkhead

A A
b0/2
b1

Plan View

Z - Axis
Section A-A

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Section 4 Initial Scantling Criteria 5C-3-4

17 Deck Girders and Main Supporting Members (1996)

17.1 General
The main supporting members such as the transverse webs and girders are to be arranged and designed as
indicated in 5C-3-4/13.1.

17.3 Hatch Side Girders

The depth of the hatch-side girder below the deck is not to be less than obtained from the following equation:
dw = c1c2lo/25 m (ft)
where
lo = length of the hatch opening, in m (ft)
c1 = 0.85 if n = 2

= 0.75 if n ≥ 3
n = number of transverse webs in the upper wing tank between two ends of the hatch
opening
c2 = 1 for upper wing tank without longitudinal bulkhead
= 0.9 for upper wing tank with longitudinal bulkhead

17.5 Hatch-End Beams

17.5.1 Section Modulus
The least net section modulus of the hatch-end beam including hatch coaming in association with
effective deck plating is not to be less than obtained from the following equation:
SM = M/fb cm3 (in3)

M is M 1 or M 2 , whichever is greater, as obtained from the following equations:

M 1 = M1 + 0.75M2

M 2 = M2 + 0.80M1

M1 = C1(0.25ql0 b02 + 0.375pl1 b02 ) 105/k1 N-cm (kgf-cm, lbf-in)

M2 = 0.08 b02 (Mc + 0.5Fch)/[sw(n + 1)] N-cm (kgf-cm, lbf-in)

if transverse bulkhead connected with hatch-end beam under consideration has
upper stool.

M2 = 0.5Mc1 b02 /[sw(n + 1)] N-cm (kgf-cm, lbf-in)

if transverse bulkhead connected with hatch-end beam under consideration does not
have upper stool.
where
k1 = 12 (12, 44.64)

C1 = 1/(1 + β3)
Mc, Mc1 = bending moment M, in N-cm (kgf-cm, lbf-in), as defined in 5C-3-4/25.5, at
the upper end of corrugation span for transverse bulkhead with upper stool
(Mc) and without upper stool (Mc1), loaded with dry cargo, ballast or liquid
cargo

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Section 4 Initial Scantling Criteria 5C-3-4

Fc = shear force, in N (kgf, lbf), at the upper end of corrugation span for transverse
bulkhead with upper stool, loaded with dry cargo, ballast or liquid cargo
= k2sl (0.125pl + 0.375pu)104
k2 = 1 (1, 0.0144)
β = 0.45 [(I/i) (b0/w)3 (n + 1)]1/4
I = net moment of inertia, in m4 (ft4), of cross deck girder or supporting bracket
closest to vessel’s centerline at the midspan of l1 (with effective deck
plating)
i = net moment of inertia, in m4 (ft4), of hatch-end beam including hatch
coaming at vessel’s centerline (with effective deck plating)
b0 = width, in m (ft), of the hatch opening
l0 = length, in m (ft), of the hatch opening
l1 = distance in m (ft) between the hatch-end beam and the adjacent transverse
bulkhead or upper stool. l1 is not to be less than 0.5w to obtain M1.
w = width of the cross deck structure, in m (ft), as shown in 5C-3-4/Figure 10
s = spacing of corrugation, in m (ft), as shown in 5C-3-4/Figure 11
h = height of the upper stool at vessel’s centerline, in cm (in.)
n = number of deck girders or supporting brackets between lines of hatch openings
q = hatch cover load, in kN/m2 (tf/m2, Ltf/ft2), at the center of hatch opening,
mimimum 20.6 kN/m2 (2.1 tf/m2, 0.192 Ltf/ft2); design hatch cover load,
green water (see 5C-3-3/5.5.4 ) or internal pressure for ballast or liquid cargo
tanks as specified in 5C-3-3/Table 3, whichever is greater
p = deck load, in kN/m2 (tf/m2, Ltf/ft2), at the midspan of l1, minimum 20.6 kN/m2
(2.1 tf/m2, 0.192 Ltf/ft2); design deck load, green water (see 5C-3-3/5.5.4) or
internal pressure for ballast or liquid cargo tanks as specified in 5C-3-3/Table 3,
whichever is greater
pl, pu, l are as defined in 5C-3-4/25.3.

fb = permissible bending stress in N/cm2 (kgf/cm2, lbf/in2)

= 0.95 Sm fy
Sm and fy are as defined in 5C-3-4/7.3.1.

17.5.2 Depth
The depth of the hatch-end beam below the deck is not to be less than that obtained from the
following equation:
dw = c1bo/20 m (ft)
where
c1 = 1.2 − 0.05n, not to be less than 0.75 and need not be greater than 1.0
n = number of the deck girders or supporting brackets inside the lines of hatch
openings
bo = width of the hatch opening, in m (ft). For calculation of dw, bo is not to be
taken less than 0.46B
B = breadth of the vessel, in m (ft), as defined in 3-1-1/5

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Section 4 Initial Scantling Criteria 5C-3-4

17.7 Deck Girders Inside the Lines of Hatch Openings

17.7.1 Section Modulus (1997)
The least net section modulus of the deck girder or supporting bracket, clear of end brackets in
association with effective deck plating, is not to be less than that obtained from the following
equation:
SM = M/fb cm3 (in3)

M is not to be less than M 1 , M 2 and M 3 , as obtained from the following equations:

M 1 = M1 + 0.75M2

M 2 = M2 + 0.80M1

M 3 = M3 + 0.70M1

M1 = 0.7k1φ1 (0.25qγ1b0l0l1 + pγ2b0 l 12 ) 105/(n + 1) N-cm (kgf-cm, lbf-in)

M2 = 0.5c1φ2b0(Mc + 0.5Fch)/[s(n + 1)] N-cm (kgf-cm, lbf-in)

if transverse bulkhead, connected with deck girder or supporting bracket under
consideration, has upper stool.
M2 = 0.5φ2Mc1b0/[s(n + 1)] N-cm (kgf-cm, lbf-in)
if transverse bulkhead, connected with deck girder or supporting bracket under
consideration, does not have upper stool.
M3 = 0.15k1kv cQ1φ2B3I 105/(w2AD2 ) N-cm (kgf-cm, lbf-in)
where
k1 = 1.0 (1.0, 0.269)

C1 = 0.3α1.5, not to be less than 0.05 and need not be greater than 0.25

γ1 = 1.03β − 0.356, not to be less than 0.05 and need not be greater than 1.0

γ2 = 0.39β − 0.0085, not to be less than 0.13 and need not be greater than 0.5
Fc, Mc and Mc1 are as defined in 5C-3-4/17.5.1 above.

Q1 = Q − 0.68P/kv

α = (b0/w)(1000I/ Ad2 )

φ1 = 1.125 − 1.25he /l1

φ2 = 1 − he /l1
he = length of the bracket of the deck girder, in m (ft), as shown in 5C-3-4/Figure 12

A = total net sectional area of cross deck structure at vessel’s centerline, in m2

(ft2), as defined in 5C-3-4/15.9.1
Ad = cross sectional area, in m2 (ft2), enclosed by the outside lines of upper stool

q, p, b0, l0, l1, w, n, h, s and β are as defined in 5C-3-4/17.5.1 above.

c, Q, P, B, and D are as defined in 5C-3-4/15.9.1.
kv is as defined in 5C-3-3/5.7.1(c) for the transverse bulkhead connected with the deck girder or
supporting bracket under consideration.

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Section 4 Initial Scantling Criteria 5C-3-4

fb = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)

= 0.95 Sm fy
Sm and fy are as defined in 5C-3-4/7.3.1.

17.7.2 Depth
The depth of the deck girder inside the lines of hatch openings is not to be less than dw1 and dw2, as
defined below.
dw1 = bo /25 m (ft)

dw2 = lo /25 m (ft)

bo and lo are as defined in 5C-3-4/17.5.1 above.

17.9 Minimum Thickness for Web Portion of Main Supporting Members

The net thickness of the web of the deck girder, supporting bracket or hatch-end beam is not to be less than
9.5 mm (0.374 in.).

FIGURE 11
Definition of Parameters for Corrugated Bulkhead
a

c
d tw
φ (NET)

s
tf (NET)

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Section 4 Initial Scantling Criteria 5C-3-4

FIGURE 12
Effectiveness of Brackets

Span Span

d/2
d/4
ha ha
d
d Length of Length of
Bracket (he) Bracket (he)

Where face plate area on the member is not carried along the face
Where face plate area on the member is carried along of the bracket,and where the face plate area on the bracket is at
the face of the bracket least one-half the face plate area on the member.

Brackets are not to be considered effective beyond the point where the arm
on the girder or web is 1.5 times the arm on the bulkhead or base.

Length of
Bracket (he)

1.5a

l1

Length of the "effective" bracket for supporting crossdeck bracket

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Section 4 Initial Scantling Criteria 5C-3-4

19 Cargo Hold Hatch Covers, Hatch Coamings and Closing

Arrangements (2004)

19.1 Application
The following requirements apply to bulk carriers, ore carriers and combination carriers, and are for all
hatch covers, hatch coamings and closing arrangements for cargo hold hatches in position 1, as defined in
3-2-15/3.1.
These requirements for hatch covers, hatch coamings and closing arrangements are in addition to those in
the applicable parts of Section 3-2-15.

19.3 Hatch Covers

These strength requirements are applicable to hatch covers of stiffened plate construction. The secondary
stiffeners and primary supporting members of the hatch covers are to be continuous over the breadth and
length of the hatch covers, as far as practical. When this is impractical, sniped end connections are not to
be used and appropriate arrangements are to be adopted to ensure sufficient load carrying capacity.
Material for the hatch covers is to be steel, in accordance with Part 2, Chapter 1. The welding procedures
including consumables are to be as required for the grade and thickness of the steel used.
19.3.1 Nominal Design Corrosion Values and Net Thickness
19.3.1(a) Nominal Design Corrosion Value. The nominal design corrosion value is to be taken as
follows:
For all structures (plating and secondary stiffeners) of single skin hatch covers:
2.0 mm (0.08 in.)
For double plated hatch covers:
top and bottom plating 2.0 mm (0.08 in.)
internal structures 1.5 mm (0.06 in.)
19.3.1(b) Net Thickness In the calculation of the hatch covers, net thickness as indicated in 5C-
3-2/1.1 is to be used.
19.3.2 Hatch Cover Design Pressures
19.3.2(a) On Freeboard Deck. Hatch covers are to withstand a design pressure, p, on the hatch
cover panels for hatchways located at the freeboard deck:
p = p0 + (pFP – p0) (0.25 – x/Lf )/0.25 kN/m2 (tf/m2, Ltf/ft2)
where
p0 = 34.3 (3.5, 0.32) kN/m2 (tf/m2, Ltf/ft2)
pFP = pressure at the forward perpendicular
= 49.0 + a(Lf – 100) kN/m2 for Lf in meters

= 5 + a(Lf – 100) tf/m2 for Lf in meters

= 0.457 + a(Lf – 328) Ltf/ft2 for Lf in feet

a = 0.0726 (0.0074, 0.000206) kN/m2 (tf/m2, Ltf/ft2), for type B freeboard

ships
= 0.356 (0.0363, 0.00101) kN/m2 (tf/m2, Ltf/ft2), for ships with reduced
freeboard

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-3-4

Lf = freeboard length, in m (ft), as defined in 3-1-1/3.3, to be taken not greater

than 340 m (1115 ft)
x = distance, in m (ft), of the mid length of the hatch cover under examination
from the forward end of Lf or 0.25Lf, whichever is less
19.3.2(b) On Superstructure Deck. Where a position 1 hatchway is located at least one superstructure
standard height higher than the freeboard deck, the pressure p may be 34.3 kN/m2 (3.5 tf/m2,
0.32 Ltf/ft2).
19.3.2(c) Mechanically Connected Covers. Where two or more panels are connected by hinges,
each individual panel is to be considered separately.
19.3.2(d) Other Considerations. For hatch covers in holds intended for the carriage of liquid, the
structure is to be of adequate strength to resist the upward pressure of ballast water or cargo oil in
the holds caused by the pitch and roll motions of the vessel specified for load cases 5 and 7 in
5C-3-3/Table 1.
Where P/V valves are fitted, the strength of the covers is to be verified for a pressure corresponding
to the P/V valve setting.
19.3.3 Allowable Stress and Deflection
19.3.3(a) Allowable Stress. The normal stress σ and shear stresses τ in the hatch cover structures
are not to exceed the allowable values, σa and τa, given by:

σa = 0.8 σF N/mm2 (kgf/mm2, psi)

τa = 0.46 σF N/mm2 (kgf/mm2, psi)

where
σF = the specified yield stress, in N/mm2 (kgf/mm2, psi), of the material.
The normal stress in compression of the plating forming the flange of primary supporting members
is not to exceed 0.8 times the critical buckling stress of the structure in 5C-3-4/19.3.7.
19.3.3(b) Allowable Deflection. The vertical deflection of primary supporting members is to be
not more than 0.0056l, where l is the greatest span of primary supporting members.
19.3.4 Top Plate Thickness
The plate thickness, t, of the hatch cover top plating is not to be less than:

p
t = ctFps mm (in.)
0.95σ F

but to be not less than the greater of 1% of the spacing of the stiffeners or 6 mm (0.24 in.).
where
ct = 0.0158 (0.0158, 1.97)
Fp = factor for combined membrane and bending response
= 1.50 in general
= 1.90σ/σa, for σ/σa ≥ 0.8, for plates forming the flange of primary
supporting members
s = stiffener spacing, in mm (in.)
p = pressure, in kN/m2 (tf/m2, Ltf/ft2), as defined in 5C-3-4/19.3.2(a) or
5C-3-4/19.3.2(b)
σ = as defined in 5C-3-4/19.3.6(a)
σa, σF = as defined in 5C-3-4/19.3.3(a)

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-3-4

19.3.5 Secondary Stiffeners

The required minimum section modulus, SM, of secondary stiffeners on the hatch cover top plate,
based on stiffener net member thickness, is given by:
l 2 sp
SM = cs cm3 (in3)
12σ a
where
cs = 1 (1, 2240)

l = secondary stiffener span, in m (ft), to be taken as the spacing, in m (ft), of

primary supporting members or the distance between a primary supporting
member and the edge support, as applicable. When brackets are fitted at both
ends of all secondary stiffener spans, the secondary stiffener span may be
reduced by an amount equal to 2/3 of the minimum brackets arm length, but
not greater than 10% of the gross span for each bracket.
s = secondary stiffener spacing, in mm (in.)
p = pressure, in kN/m2 (tf/m2, Ltf/ft2), as defined in 5C-3-4/19.3.2(a) or
5C-3-4/19.3.2(b)
σa = as defined in 5C-3-4/19.3.3(a)
The net section modulus of the secondary stiffeners is to be determined based on an attached plate
width assumed equal to the stiffener spacing.
19.3.6 Primary Supporting Members
The spacing of primary supporting members parallel to the direction of secondary stiffeners is not
to exceed 1/3 of the span of primary supporting members.
Where it is intended that the covers may carry containers, the requirements of 3-2-15/9.9 are also
to be satisfied.
19.3.6(a) Scantlings. The section modulus and web thickness of primary supporting members,
based on member net thickness, are to be such that the normal stress σ in both flanges and the
shear stress τ, in the web, do not exceed the allowable values σa and τa, respectively, as defined in
5C-3-4/19.3.3(a).
The stresses in hatch covers that are designed as a grillage of longitudinal and transverse primary
supporting members are to be determined by a grillage or a finite element analysis.
19.3.6(b) Effective Flange Area. The effective flange area, Af, of the plating forming the flange,
to be considered for the yielding and buckling checks of primary supporting members, when
calculated by means of a beam or grillage model, is obtained as the sum of the effective flange
areas of each side of the girder web as indicated below:
⎛ bef t ⎞
Af = ∑ ⎜⎜⎝ c
nf a ⎠
⎟ cm2 (in2)
⎟

where
ca = 100 (100, 1)
nf = 2 if the plate extends on both sides of web
= 1 if the plate extends on one side of web only
t = net thickness of plate under consideration, in mm (in.)

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-3-4

bef = effective breadth of flange on each side of web

= bp, but not to be taken greater than:
= 165l mm for l in m
= 2l in. for l in ft
bp = half distance, in m (ft), between the primary supporting member under
consideration and the adjacent one
l = span, in m (ft), of primary supporting member under consideration
When a beam or a grillage analysis is used, the secondary stiffeners are not to be included in the
attached flange area of the primary members.
19.3.6(c) Flanges. The breadth of flange is to be not less than 40% of the depth of the primary
supporting member where the distance between lateral supports is greater than 3.0 m (10 ft).
Tripping brackets attached to the flange may be considered as a lateral support for the flange.
The outstanding flange is not to exceed 15 times the flange thickness.
19.3.7 Critical Buckling Stress
19.3.7(a) Hatch Cover Plating
i) Parallel to Secondary Stiffener. The compressive stress σ in the hatch cover plate panels,
induced by the bending of primary supporting members parallel to the direction of
secondary stiffeners, is not to exceed 0.8 times the critical buckling stress σC1, to be
evaluated as defined below:
σC1 = σE1 when σE1 ≤ σF/2

= σF[1 – σF/(4σE1)] when σE1 > σF/2

where
σF = as defined in 5C-3-4/19.3.3(a)
2
σE1 = ⎛t⎞ N/mm2 (kgf/mm2, psi)
3.6 E ⎜ ⎟
⎝s⎠
E = modulus of elasticity of steel
= 2.06 × 105 N/mm2 (21,000 kgf/mm2, 30 × 106 psi)
t = net thickness, in mm (in.), of plate panel
s = spacing, in mm (in.), of secondary stiffeners
ii) Perpendicular to Secondary Stiffener. The mean compressive stress σ in each of the hatch
cover plate panels, induced by the bending of primary supporting members perpendicular
to the direction of secondary stiffeners, is not to exceed 0.8 times the critical buckling
stress σC2as defined below:
σC2 = σE2 when σE2 ≤ σF/2
= σF[1 – σF/(4σE2)] when σE2 > σF/2
where
2
⎛ t ⎞
σE2 = 0.9mE ⎜⎜ ⎟ N/mm2 (kgf/mm2, psi)
⎟
⎝ ss ⎠

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-3-4

2
⎡ ⎛s ⎞
2⎤
2.1
m = c ⎢1 + ⎜⎜ s ⎟
⎟
⎥
⎢ ⎝ls ⎠ ⎥ Ψ + 1.1
⎣ ⎦
ss = length, in mm (in.), of the shorter side of the plate panel

ls = length, in mm (in.), of the longer side of the plate panel

Ψ = ratio of smallest to largest compressive stress

c = 1.3 when plating is stiffened by primary supporting members
= 1.21 when plating is stiffened by secondary stiffeners of angle or
T type
= 1.1 when plating is stiffened by secondary stiffeners of bulb type
= 1.05 when plating is stiffened by flat bar
iii) Biaxial Compression. The biaxial compressive stress in the hatch cover panels, when
calculated by means of FEM shell element model, is to be in accordance with the Rules as
deemed equivalent to the above criteria.
19.3.7(b) Hatch Cover Secondary Stiffeners. The compressive stress σ in the top flange of secondary
stiffeners, induced by the bending of primary supporting members parallel to the direction of
secondary stiffeners, is not to exceed 0.8 times the critical buckling stress σCS as defined below:

σCS = σES when σES ≤ σF/2

= σES [1 – σF/(4σES)] when σES > σF/2

where
σF = as defined in 5C-3-4/19.3.3(a)
σES = ideal elastic buckling stress, in N/mm2 (kgf/mm2, psi), of the secondary
stiffener
= the lesser of σE3 and σE4

σE3 = E Ia/(c1Al2) N/mm2 (kgf/mm2, psi)

E = as defined in 5C-3-4/19.3.7(a)
Ia = moment of inertia, in cm4 (in4), of the secondary stiffener, including a top
flange equal to the spacing of secondary stiffeners
c1 = 1000 (1000, 14.4)
A = cross-sectional area, in cm2 (in2), of the secondary stiffener, including a top
flange equal to the spacing of secondary stiffeners
l = span, in m (ft), of the secondary stiffener

π 2 EI w ⎛ K ⎞ I
σE4 = 2
2
⎜ m + 2 ⎟ + 0.385 E t N/mm2 (kgf/mm2, psi)
10c1 I p l ⎝ m ⎠ Ip

Cl 4
K = c2
π 4 EI w
c2 = 106 (106, 20736)
m = number of half waves, given by the following table:

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-3-4

0<K≤4 4 < K ≤ 36 36 < K ≤ 144 (m – 1)2 m2 < K ≤ m2 (m + 1)2

m 1 2 3 M

It = St Venant’s moment of inertia, in cm4 (in4), of the secondary stiffener

without top flange

hw t w3
= c3 for flat bar secondary stiffeners
3

1⎡ 3 ⎛ tf ⎞⎤
= c3 ⎢hw t w + b f t 3f ⎜1 − 0.63 ⎟⎥ for flanged secondary stiffeners
3⎢ ⎜ bf ⎟⎥
⎣ ⎝ ⎠⎦
c3 = 10-4 (10-4, 1)
Ip = polar moment of inertia, in cm4 (in4), of the secondary stiffener about its
connection with the plating

hw3 t w
= c3 for flat bar secondary stiffeners
3

⎛ h3 t ⎞
= c3 ⎜ w w + hw2 b f t f ⎟ for flanged secondary stiffeners
⎜ 3 ⎟
⎝ ⎠
Iw = sectorial moment of inertia, in cm6 (in6), of the secondary stiffener about its
connection with the plating

hw3 t w3
= c4 for flat bar secondary stiffeners
3

t f b 3f hw2
= c4 for “Tee” secondary stiffeners
12

= c4
b 3f hw2
12(b f + hw ) 2
[t (b
f
2
f )
+ 2b f hw + 4hw2 + 3t w b f hw ]
for angles and bulb secondary stiffeners
c4 = 10-6 (10-6, 1)
hw, tw = height and net thickness, in mm (in.), of the secondary stiffener web,
respectively
bf, tf = width and net thickness, in mm (in.), of the secondary stiffener bottom
flange, respectively
s = spacing, in mm (in.), of secondary stiffeners
C = spring stiffness exerted by the hatch cover top plating
k p Et 3p
= N (kgf, lbf)
⎛ 1.33k p hw t 3p ⎞
3s⎜1 + ⎟
⎜ st w3 ⎟
⎝ ⎠
kp = 1 – ηp
= to be taken not less than zero; for flanged secondary stiffeners, kp need not be
taken less than 0.1

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-3-4

σ
ηp =
σ E1
σ = as defined in 5C-3-4/19.3.6(a)
σE1 = as defined in 5C-3-4/19.3.7(a)
tp = net thickness, in mm (in.), of the hatch cover plate panel.
For flat bar secondary stiffeners and buckling stiffeners, the ratio h/tW is to be not greater than
15k0.5, where:
h, tW = height and net thickness, in mm (in.), of the stiffener, respectively

k = Y/σF

Y = 235 N/mm2 (24 kgf/mm2, 34000 psi)

σF = as defined in 5C-3-4/19.3.3(a)
19.3.7(c) Web of primary supporting members. This check is to be carried out for the web panels
of primary supporting members, bounded by web stiffeners or other crossing members, the face
plate (or the bottom cover plate) and the top plate.
The shear stress τ in the hatch cover primary supporting member web panels is not to exceed 0.8
times the critical buckling stress τC, as defined below:

τC = τE when τE ≤ τF/2

= τF [1 − τF/(4τE)] when τE > τF/2

where
σF = as defined in 5C-3-4/19.3.3(a)

τF = σF/ 3
τE = 0.9kt E (tpr,n/d)2
E = as defined in 5C-3-4/19.3.7(a)
tpr,n = net thickness, in mm (in.), of primary supporting member

kt = 5.35 + 4.0/(a/d)2
a = greater dimension, in mm (in.), of web panel of primary supporting member
d = smaller dimension, in mm (in.), of web panel of primary supporting member
For primary supporting members parallel to the direction of secondary stiffeners, the actual dimensions
of the panels are to be considered.
For primary supporting members perpendicular to the direction of secondary stiffeners or for
hatch covers built without secondary stiffeners, a presumed square panel of dimension d is to be
taken for the determination of the stress τC In such a case, the average shear stress τ between the
values calculated at the ends of this panel is to be considered.
19.3.8 Connections between Hatch Cover Panels
Load bearing connections are to be fitted between the hatch cover panels to restrict the relative
vertical displacements.

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-3-4

19.5 Hatch Coamings

19.5.1 Nominal Design Corrosion Values and Net Thickness
19.5.1(a) Nominal Design Corrosion Values. The nominal design corrosion value is to be taken
as follows:
In general, for compliance with 5C-3-4/19.5 and 1.5 mm (0.06 in.)
5C-3-4/19.7, except below:
For compliance with 5C-3-4/19.5.6 1.0 mm (0.04 in.)
19.5.1(b) Net Thickness. In the calculation of the hatch coaming scantlings, net thickness as
indicated in 5C-3-2/1.1 is to be used.
19.5.2 Design Pressures
19.5.2(a) Green Sea Pressure
i) The pressure, pcoam, on the No. 1 forward transverse hatch coaming is given by:
pcoam = 220 (22.4, 2.05) kN/m2 (tf/m2, Ltf/ft2), when a forecastle is fitted in
accordance with 5C-3-1/7
= 290 (29.6, 2.70) kN/m2 (tf/m2, Ltf/ft2), in the other cases
ii) The pressure, pcoam, on the other forward end and all side coamings is given by:

pcoam = 220 (22.4, 2.05) kN/m2 (tf/m2, Ltf/ft2)

19.5.2(b) Other Considerations. For hatch coamings in holds intended for carriage of liquid, the
structure is to be of adequate strength to resist the upward pressure of ballast water or cargo oil in
the holds caused by the pitch and roll motions of the vessel specified for load cases 5 and 7 in
5C-3-3/Table 1.
19.5.3 Coaming Plate Thickness
The coaming plate thickness t is given by:

p coam
t = C coam s S coam mm (in.)
σ a ,coam

where
ccoam = 0.0149 (0.0149, 1.86)
s = secondary stiffener spacing, in mm (in.)
pcoam = pressure, in kN/m2 (tf/m2, Ltf/ft2), as defined in 5C-3-4/19.5.2(a)
Scoam = safety factor to be taken equal to 1.15

σa,coam = 0.95σF
The coaming plate thickness is to be not less than 9.5 mm (0.37 in.).
19.5.4 Secondary Stiffeners
The secondary stiffeners of the hatch coamings are to be continuous over the breadth and length of
the hatch coamings.
The required section modulus, SM, of the longitudinal or transverse secondary stiffeners of the
hatch coamings, based on net member thickness, is given by:

S coam l 2 sp coam
SM = c s cm3 (in3)
mc pσ a ,coam

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-3-4

where
cs = 1 (1, 2240)
m = 16 in general
= 12 for the end spans of stiffeners
Scoam = safety factor, to be taken equal to 1.15

l = span, in m (ft), of secondary stiffeners

s = spacing, in mm (in.), of secondary stiffeners
pcoam = pressure, in kN/m2 (tf/m2, Ltf/ft2), as defined in 5C-3-4/19.5.2(a)
cp = ratio of the plastic section modulus to the elastic section modulus of the
secondary stiffeners with an attached plate breadth, in mm (in.), equal to 40t,
where t is the plate net thickness
= 1.16 in the absence of more precise evaluation
σa,coam = 0.95σF

19.5.5 Stays
19.5.5(a) Flange End Connected. The required minimum section modulus, SM, and web thickness,
tw, of coaming stays designed as beams with flange connected to the deck or sniped and fitted with
a bracket (see 5C-3-4/Figures 13 and 14) at their connection with the deck, based on member net
thickness, are given by:

c s H c2 sp coam
SM = cm3 (in3)
2σ a ,coam

cc H c sp coam
tw = mm (in.)
hτ a ,coam

where
cs = 1 (1, 2240)
cc = 1 (1, 187)
Hc = stay height, in m (ft)
s = stay spacing, in mm (in.)
h = stay depth, in mm (in.), at the connection with the deck
pcoam = pressure, in kN/m2 (tf/m2, Ltf/ft2), as defined in 5C-3-4/19.5.2(a)

σa,coam = 0.95σF

τa,coam = 0.5σF
For calculating the section modulus of coaming stays, their face plate area is to be taken into
account only when it is welded with full penetration welds to the deck plating and adequate
underdeck structure is fitted to support the stresses transmitted by it.
19.5.5(b) Flange End Sniped. For other designs of coaming stays, such as, for example, those
shown in 5C-3-4/Figures 15 and 16, the stress levels in 5C-3-4/19.3.3(a) will apply in lieu of
σa,coam and τa,coam. The highest stressed locations are to be checked.

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Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-3-4

FIGURE 13

FIGURE 14

406 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-3-4

FIGURE 15

FIGURE 16

19.5.6 Long Side Coamings

The thickness of continuous longitudinal coamings having a length greater than 0.14L is not to be
less than the value of t3, given in 5C-3-4/15.1, with s taken as the spacing of the coaming stiffeners.
The stiffeners are to comply with the requirements of 5C-3-4/15.3, where l is the distance between
bracket, and p is not to be less than 1.59 N/cm2 (0.1625 kgf/cm2, 2.31 psi).
19.5.7 Local Details
Local details are to be designed for the purpose of transferring the pressures on the hatch covers to
the hatch coamings and, through them, to the deck structures below. Hatch coamings and supporting
structures are to be adequately stiffened to accommodate the loading from hatch covers, in longitudinal,
transverse and vertical directions.

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-3-4

Underdeck structures are to be checked against the load transmitted by the stays, adopting the
same allowable stresses specified in 5C-3-4/19.5.5(a).
Where rubbing bars (e.g., a half-round bar) are provided on the hatch side girders (i.e., upper
portion of top side tank plates)/hatch end beams in cargo hold and/or upper portion of hatch
coamings, the material of the rubbing bars is to be of Grade A steel or equivalent. Termination of
these rubbing bars is to comply with 3-1-2/15.3.
Unless otherwise stated, weld connections and materials are to be in accordance with the applicable
requirements in Section 3-2-19.
Double continuous welding is to be adopted for the connections of stay webs with deck plating
and the weld throat is to be not less than 0.44 tW, where tW is the gross thickness of the stay web.
Toes of stay webs are to be connected to the deck plating with deep penetration double bevel
welds extending over a distance not less than 15% of the stay width.

19.7 Closing Arrangements

19.7.1 Securing Arrangements
19.7.1(a) Securing Device. Hatch cover panels are to be secured by appropriate devices (bolts,
wedges or similar) suitably spaced alongside the coamings and between panels.
Arrangement and spacing are to be determined with due attention to the weathertightness, the type
and the size of the hatch cover, as well as the stiffness of the cover edges between the securing
devices.
Securing devices are to be of reliable construction and securely attached to the hatchway
coamings, decks or covers. Individual securing devices on each cover are to have approximately
the same stiffness characteristics.
Where rod cleats are fitted, resilient washers or cushions are to be incorporated.
Where hydraulic cleating is adopted, a positive means is to be provided to ensure that it remains
mechanically locked in the closed position in the event of failure of the hydraulic system.
19.7.1(b) Sectional Area. Subject to 5C-3-4/19.7.1(c), the net sectional area of each securing
device is not to be less than:
A = csd a/f cm2 (in2)
where
csd = 1.4 (1.4, 0.066)
a = spacing, in m (ft), of securing devices, not to be taken less than 2 m (6.6 ft)
f = (σY/Y)e

Y = 235 N/mm2 (24 kgf/mm2, 34,000 psi)

σY = specified minimum upper yield stress, in N/mm2 (kgf/mm2, psi), of the steel,
not to be taken greater than 70% of the ultimate tensile strength.
e = 0.75 for σY > 235 N/mm2 (24 kgf/mm2, 34,000 psi)

= 1.0 for σY < 235 N/mm2 (24 kgf/mm2, 34,000 psi)

Rods or bolts are to have a net diameter not less than 19 mm (0.75 in.) for hatchways exceeding
5 m2 (54 ft2) in area.
19.7.1(c) Packing Line Pressure. Between cover and coaming and at cross-joints, a packing line
pressure sufficient to obtain weathertightness is to be maintained by the securing devices.
For packing line pressures exceeding 5 N/mm2 (0.51 kgf/mm2, 28.6 psi), the cross section area of
the securing device is to be increased in direct proportion. The packing line pressure is to be specified.

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Section 4 Initial Scantling Criteria 5C-3-4

19.7.1(d) Edge Stiffness. The cover edge stiffness is to be sufficient to maintain adequate sealing
pressure between securing devices. The moment of inertia, I, of edge elements is not to be less than:
I = ci p a4 cm4 (in4)
where
ci = 6 (58.8, 0.000218)
p = packing line pressure, in N/mm2 (kgf/mm2, psi), minimum 5 N/mm2 (0.51
kgf/mm2, 28.6 psi).
a = spacing, in m (ft), of securing devices.
19.7.2 Stoppers
19.7.2(a) Forces. All hatch covers are to be fitted with stoppers to limit horizontal movement of
the cover against the forces caused by the following pressures:
i) Longitudinal pressure on fore end of cover:
No. 1 hatch cover:
where a forecastle in accordance with 5C-3-1/7 is not fitted:
230 kN/m2 (23.5 tf/m2, 2.14 Ltf/ft2)
where a forecastle in accordance with 5C-3-1/7 is fitted:
175 kN/m2 (17.8 tf/m2, 1.63 Ltf/ft2)
Other hatch covers: 175 kN/m2 (17.8 tf/m2, 1.63 Ltf/ft2).
ii) Transverse pressure on side of cover:
All hatch covers:175 kN/m2 (17.8 tf/m2, 1.63 Ltf/ft2).
19.7.2(b) Allowable Stresses. The equivalent stress:
i) in stoppers and their supporting structures, and
ii) calculated in the throat of the stopper welds
is not to exceed 0.8 σY under the above pressures.

19.7.3 Materials and Welding

Stoppers and securing devices are to be manufactured of materials and corresponding welding
procedures and consumables, in accordance with applicable requirements of Part 2.

21 Longitudinal Bulkheads

21.1 Sloping Bulkhead Plating of Lower Wing Tank (1999)

The net thickness of the lower wing tank sloping bulkhead plating, in addition to complying with 5C-3-4/5.5,
is to be not less than t1, t2 and t3 for the amidship 0.4L, as obtained from the following equations:
t1 = 0.73s(k1p/f1)1/2 mm (in.)

t2 = 0.73s(k2p/f2)1/2 mm (in.)

t3 = cs(Sm fy /E)1/2 mm (in.)

but not to be less than 9.5 mm (0.37 in.)

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Section 4 Initial Scantling Criteria 5C-3-4

where
s = spacing of the longitudinal bulkhead longitudinals, in mm (in.)
k1 = 0.342
k2 = 0.5

p = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), at the lower edge of each plate, as
specified in 5C-3-3/Table 3
Where upper and lower wing tanks are connected by trunks or double sides, the nominal pressure, p, in
load case “b” of 5C-3-3/Table 3 may be modified by the following equation:
p = pb − puo
pb is nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), at the lower edge of each plate, as defined in load case
“b” of 5C-3-3/Table 3 for sloping bulkhead plating of the lower wing tank.
puo is as defined in 5C-3-4/9.1.
The net thickness, t3, may be determined based on Sm and fy of the hull girder strength material required at
the location under consideration.
f1 = permissible bending stress, in the longitudinal direction, in N/cm2 (kgf/cm2, lbf/in2)

= [1 − 0.4 (z/B) − 0.52α1(SMRB /SMB)(y/yn)]Sm fy ≤ 0.60Sm fy, for dry cargo loads

= [1 − 0.4 (z/B) − 0.52α1(SMRB /SMB)(y/yn)]Sm fy, for ballast/liquid loads

SMB/SMRB is not to be taken more than 1.2α1 or 1.4, whichever is lesser.

α1 = Sm1 fy1/Sm fy
Sm = strength reduction factor of the bulkhead plating, as defined in 5C-3-4/7.3.1
fy = minimum specified yield point of the bulkhead plating, in N/cm2 (kgf/cm2, lbf/in2)
z = transverse distance, in m (ft), measured from the centerline of the section to the lower
edge of the bulkhead strake under consideration
y = vertical distance, in m (ft), measured from the neutral axis of the hull girder
transverse section to the lower edge of the bulkhead strake under consideration.
yn = vertical distance, in m (ft), measured from the bottom to the neutral axis of the
section
f2 = permissible bending stress, in the vertical direction

= 0.85 Sm fy , in N/cm2 (kgf/cm2, lbf/in2), for dry cargo loads

= Sm fy , in N/cm2 (kgf/cm2, lbf/in2) for ballast/liquid loads

B = vessel’s breadth, in m (ft), as defined in 3-1-1/5
c = 0.7N 2 − 0.2, not to be less than 0.33, but need not be greater than 0.45(Q/Qb)1/2
N = Rb [(Q/Qb)(y/yn)]1/2
Q = material conversion factor in 5C-3-4/5 for the bulkhead plating
SMRB, SMB, Rb, Qb and E are as defined in 5C-3-4/7.3.1.
Sm1 and fy1 are as defined in 5C-3-4/7.5.

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Section 4 Initial Scantling Criteria 5C-3-4

The sloping bulkhead is to be longitudinally framed in the lower wing tank, except the upper part of the
lower wing tank where the limited access makes longitudinal framing impractical. This part of the sloping
bulkhead may be transversely framed with efficient brackets arranged in line with the side frames, provided
the net thickness of sloping bulkhead plating here is not less than that of the adjacent longitudinally framed
bulkhead plating and is also not less than t4, obtained from the following equation:

t4 = 0.73sk(k2 p/f)1/2 mm (in.)

where
s = spacing of the transverse brackets, in mm (in.)

k = (3.075 α − 2.072)/(α + 0.272) (1≤ α ≤ 2)

= 1.0 (α > 2)
k2 = 0.5

α = aspect ratio of the panel (longer edge/shorter edge)

p = nominal pressure, as defined above
f = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= [1 − 0.4 (z/B) − 0.52α1(SMRB /SMB)(y/yn)]Sm fy ,

SMB /SMRB is not to be taken more than 1.2α1 or 1.4, whichever is lesser.
All other parameters are as defined above.

21.3 Sloping Bulkhead Plating of Upper Wing Tank (1999)

The net thickness of the upper wing tank sloping bulkhead plating, in addition to complying with
5C-3-4/5.5, is not to be less than t1, t2 and t3, as specified below:
t1 = 0.73s(k1p/f1)1/2 mm (in.)

t2 = 0.73s(k2 p/f2)1/2 mm (in.)

t3 = cs(Sm fy /E)1/2 mm (in.)

but not to be less than 9.5 mm (0.37 in.)
where
s = spacing of longitudinal bulkhead longitudinals, in mm (in.)
k1 = 0.342
k2 = 0.50

p = pn − puo
pn is nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), at the lower edge of each plate, as defined in
5C-3-3/Table 3 for sloping plating of the upper wing tank in dry cargo holds.
puo is as defined in 5C-3-4/9.1.
The net thickness, t3, may be determined based on Sm and fy of the hull girder strength material required at
the location under consideration.
f1 = permissible bending stress, in the longitudinal direction, in N/cm2 (kgf/cm2, lbf/in2)

= 1.2[1 − 0.4(z/B) − 0.52α2(SMRD /SMD)(y/yn)] Sm fy, above the neutral axis

α2 = Sm2 fy2 /Sm fy

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Section 4 Initial Scantling Criteria 5C-3-4

yn = vertical distance, in m (ft), measured from the deck to the neutral axis of the section
f2 = permissible bending stress, in the vertical direction
= 0.8 Sm fy, in N/cm2 (kgf/cm2, lbf/in2)

c = 0.7N2 − 0.2
c for the top strake is not to be taken less than 0.4Q1/2, but need not be greater than 0.45. c for other strakes
is not to be taken less than 0.33, but need not be greater than 0.45(Q/Qd)1/2.

N = Rd [(Q/Qd)(y/yn)]1/2
Q = material conversion factor in 5C-3-4/5 for the bulkhead plating
y = vertical distance, in m (ft), measured from the neutral axis of the hull girder
transverse section to the upper edge of the bulkhead strake
yn = vertical distance, in m (ft), measured from the deck to the neutral axis of the section
B = vessel’s breadth, in m (ft), as defined in 3-1-1/5
E is as defined in 5C-3-4/7.3.1.
Rd and Qd are as defined in 5C-3-4/9.1.
SMRD and SMD are as defined in 5C-3-4/9.3.
Sm2 and fy2 are as defined in 5C-3-4/15.3.
Sm, fy , z, y and B are as defined in 5C-3-4/21.1.
The sloping bulkhead is to be longitudinally framed in the upper wing tank, except the lower part of the
upper wing tank where the limited access makes longitudinal framing impractical. This part of the sloping
bulkhead may be transversely framed with efficient brackets arranged in line with the side frames,
provided the net thickness of the sloping bulkhead plating in this area is not less than that of the adjacent
longitudinally framed bulkhead plating and is also not less than t4, obtained from the following equation:

t4 = 0.73sk(k2 p/f )1/2 mm (in.)

where
s = spacing of transverse brackets, in mm (in.)

k = (3.075 α − 2.077)/(α + 0.272) (1 ≤ α ≤ 2)

= 1.0 (α > 2)
α = aspect ratio of the panel (longer edge/shorter edge)
k2 = 0.5
p = nominal pressure as defined above
f = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= 1.2[1 − 0.4(z/B) − 0.52α2(SMRD /SMD)(y/yn)]Sm fy
All other parameters are as defined above.
The minimum vertical extent of the top strake from the upper deck for the midship 0.4L is to be obtained
from the following equation:
b = 5L + 800 mm for L ≤ 200 m
= 0.06L + 31.5 in. for L ≤ 656 ft
b = 1800 mm for 200 < L ≤ 500 m
= 70.87 in. for 656 < L ≤ 1640 ft

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Section 4 Initial Scantling Criteria 5C-3-4

L = length of the vessel, as defined in 3-1-1/3.1, in m (ft)

b = vertical extent of the top strake, in mm (in.)

21.5 Non-tight Bulkhead in Upper Wing Tank Where Adjacent to Cargo Hold (1999)
The net thickness of the non-tight longitudinal bulkhead plating, where fitted in the upper wing tank, is not
to be less than obtained from the following equation.
The net thickness, t, may be determined based on Sm and fy of the hull girder strength material required at
the location under consideration.
t = cs (Sm fy /E)1/2 mm (in.)
but not to be less than 13 mm (0.51 in.)
where
c = 0.7N2 − 0.2, not to be less than 0.33, but need not be greater than 0.45(Q/Qd)1/2.
N is as defined in 5C-3-4/21.3.
E is as defined in 5C-3-4/7.3.1.
Sm and fy are as defined in 5C-3-4/21.1.

21.7 Non-tight Bulkhead in Upper Wing Tank where Adjacent to Ballast or Liquid Cargo
Hold (1999)
The net thickness of the non-tight longitudinal bulkhead plating, where fitted in the upper wing tank, is not
to be less than t1 and t2, obtained from the following equation.
The net thickness, t2, may be determined based on Sm and fy of the hull girder strength material required at
the location under consideration.
t1 = 0.1F/(hfs) mm (in.)

t2 = 0.37s(Sm fy /E)1/2 mm (in.)

but not to be less than 13 mm (0.51 in.)
F = kpLH bsu N (kgf, lbf)
where
k = 180 (180, 403.2)
p = nominal pressure, in kN/m2 (tf/m2, Ltf/ft2), at the intersection of longitudinal
bulkhead and sloping bulkhead, as specified in 5C-3-3/Table 3
LH = length of the ballast or liquid cargo hold, in m (ft)
bsu = width of the sloping bulkhead, as indicated in 5C-3-4/Figure 9, in m (ft)
h = height of the longitudinal bulkhead, in m (ft)
s = spacing of longitudinal bulkhead longitudinals, in mm (in.)
fs = permissible shear stress, N/cm2 (kgf/cm2, lbf/in2)
= 0.5 Sm fy
Sm, fy, E are as defined in 5C-3-4/7.3.1.

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Section 4 Initial Scantling Criteria 5C-3-4

21.9 Inner Hull Longitudinal Bulkhead (1996)

21.9.1 General
The net thickness of the inner hull longitudinal bulkhead plating, where fitted between the upper
and lower wing tanks, in addition to complying with 5C-3-4/5.7, is to be not less than t, as
specified below:
21.9.2 Transversely Framed Plating (2003)
t = 0.73s(kp/f )1/2 mm (in.)
but not to be less than 9.5 mm (0.37 in.)
where
s = spacing of vertical stiffeners, in mm (in.)
k = 0.5
p = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), at the lower edge of each plate,
as specified in 5C-3-3/Table 3
Where the double hull side space is a void space, the nominal pressure, p, is to be the value in
5C-3-3/Table3 for other bulkhead plating or pv, as specified below, whichever is greater:
Pv = k1ρ (D – h) N/cm2 (kgf/cm2, lbf/in2)
k1 = conversion factor, to be taken as 0.981 (0.0981, 1/144)
ρ = density of sea water, 1.025 t/m3 (64 lb/ft3)
D = the molded depth of the vessel, in m (ft), defined in 3-1-1/7.1
h = vertical distance, in m (ft) from the baseline to the lower edge of the plate
being considered
Where the double hull space is connected to the upper wing tank, the nominal pressure, p, in load
case “b” may be modified by the following equation:
p = pb − puo
pb is nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), at the lower edge of each plate, as defined in
load case “b” of 5C-3-3/Table 3 for other bulkhead plating.
puo is as defined in 5C-3-4/9.1.

f = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)

= 0.75 Sm fy
Sm and fy are as defined in 5C-3-4/7.5.

21.9.3 Longitudinally Framed Plating (1999)

t1 = 0.73s(k1 p/f1)1/2 mm (in.)
t2 = 0.73s(k2 p/f2)1/2 mm (in.)
1/2
t3 = cs(Sm fy/E) mm (in.)
but not to be less than 9.5 mm (0.37 in.)
where
s = spacing of inner hull bulkhead longitudinals, in mm (in.)
k1 = 0.342
k2 = 0.5
p = nominal pressure, as defined in 5C-3-4/21.9.2

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The net thickness, t3, may be determined based on Sm and fy of the hull girder strength material
required at the location under consideration.
f1 = permissible bending stress, in the longitudinal direction, in N/cm2 (kgf/cm2,
lbf/in2)
= [1 − 0.4(z/B) − 0.52α1(SMRB /SMB)(y/yn)] Sm fy ≤ 0.60Sm fy for dry cargo
loads, below neutral axis
= [1 − 0.4(z/B) − 0.52α1(SMRB /SMB)(y/yn)] Sm fy for ballast/liquid loads, below
neutral axis
= 0.60 Sm fy for dry cargo loads, above neutral axis
= 1.2[1 − 0.4(z/B) − 0.52α2(SMRD /SMD)(y/yn)] Sm fy for ballast/liquid loads,
above neutral axis
SMB/SMRB is not to be taken more than 1.2α1 or 1.4, whichever is lesser.
yn = vertical distance, in m (ft), measured from the deck (bottom) to the neutral
axis of the section, when the strake under consideration is above (below) the
neutral axis
f2 = permissible bending stress, in the vertical direction
= 0.85 Sm fy in N/cm2 (kgf/cm2, lbf/in2) for dry cargo loads
= S m fy in N/cm2 (kgf/cm2, lbf/in2) for ballast/liquid loads,
below the neutral axis.
= 0.80 Sm fy in N/cm2 (kgf/cm2, lbf/in2) for ballast/liquid loads,
above the neutral axis
c = 0.7N 2 − 0.2, not to be taken less than 0.33, but need not be greater than
0.45(Q/Qd)1/2 for the strake above the neutral axis nor 0.45(Q/Qb)1/2 for the
strake below the neutral axis
N = Rd [(Q/Qd)(y/yn)]1/2 for strake above the neutral axis

= Rb [(Q/Qb)(y/yn)]1/2 for strake below the neutral axis

y = vertical distance, in m (ft), measured from the neutral axis of the hull girder
transverse section to the upper edge (lower edge) of the bulkhead strake,
when the strake under consideration is above (below) the neutral axis for N
= vertical distance, in m (ft), measured from the neutral axis of the hull girder
transverse section to the lower edge of the bulkhead strake under
consideration for f1
yn = vertical distance, in m (ft), measured from the deck (bottom) to the neutral
axis of the section, when the strake under consideration is above (below) the
neutral axis
Q = material conversion factor in 5C-3-4/5 for the bulkhead plating
SMRB, SMB, Rb and Qb are as defined in 5C-3-4/7.3.1.
Rd and Qd are as defined in 5C-3-4/9.1.
SMRD and SMD are as defined in 5C-3-4/9.3.

α1, Sm, fy, y and B are as defined in 5C-3-4/21.1.

α2 is as defined in 5C-3-4/21.3.

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Section 4 Initial Scantling Criteria 5C-3-4

21.11 Longitudinal and Vertical Stiffeners (1996)

The net section modulus of each longitudinal or vertical stiffener on longitudinal bulkheads, in association
with the effective plating to which it is attached, is not to be less than obtained from the following equation:
SM = M/fb in cm3 (in3)

M = 1000c1psl2/k in N-cm (kgf-cm, lbf-in)

where
k = 12 (12, 83.33)
c1 = 1.0 for longitudinals and horizontal stiffeners

= 1 + γl/10p for vertical stiffeners

γ = specific weight of the liquid, ≥ 1.005 N/cm2-m (0.1025 kgf/cm2-m, 0.444 lbf/in2-ft)
s = spacing of longitudinals or vertical stiffeners, in mm (in.)
l = span of longitudinals or stiffeners between effective supports, in m (ft)
p = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), at the longitudinal or stiffener considered
as specified in 5C-3-4/21.1, 5C-3-4/21.3, 5C-3-4/21.9, and 5C-3-4/7.13. For vertical
stiffeners, pressure is to be taken at the middle of span of each stiffener
fb = permissible bending stresses, in N/cm2 (kgf/cm2, lbf/in2)
= 0.70 Sm fy for vertical stiffeners of dry cargo loads
= 0.80 Sm fy for vertical stiffeners of ballast/liquid loads
fb = 1.4[1 − 0.4(z/B) − 0.52α1(SMRB /SMB)(y/yn)]Sm fy ≤ 0.70Sm fy, for longitudinal
bulkhead longitudinals of dry cargo loads, below neutral axis
= 1.4[1 − 0.4(z/B) − 0.52α1(SMRB /SMB)(y/yn)]Sm fy ≤ 0.90Sm fy, for longitudinal
bulkhead longitudinals of ballast/ liquid loads, below neutral axis
= 2.2[1 − 0.4(z/B) − 0.52α2(SMRD /SMD)(y/yn)]Sm fy ≤ 0.90Sm fy, for longitudinal
bulkhead longitudinals, above neutral axis
z = transverse distance, in m (ft), measured from the centerline of the hull girder
transverse section to the longitudinal under consideration at its connection to the
associated plate
B = vessel’s breadth, in m (ft), as defined in 3-1-1/5
Sm, fy and α1 are as defined in 5C-3-4/7.5.

α2, y, yn, SMRD and SMD are as defined in 5C-3-4/9.3.

SMRB and SMB are as defined in 5C-3-4/7.3.1.
The effective breadth of plating, be, is as defined in 5C-3-47.5.
The net moment of inertia of each longitudinal on the longitudinal bulkhead, with the associated effective
plating (bwL·tn), within the region of 0.1D from the deck at side is to be not less than io, as specified in
5C-3-4/9.3.

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Section 4 Initial Scantling Criteria 5C-3-4

23 Plane Transverse Bulkheads (1999)

23.1 Plating (1999)

The net thickness of transverse bulkhead plating is to be not less than t, as specified below:
t = 0.73sk(k2p/f )1/2 in mm (in.)
but not to be less than 9.5 mm (0.37 in.)
where
s = spacing of transverse bulkhead stiffeners, in mm (in.)
k2 = 0.50
k = (3.075(α)1/2 − 2.077)/(α + 0.272), (1 ≤ α ≤ 2)
= 1.0, (α > 2)
α = aspect ratio of the panel (longer edge/shorter edge)
p = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), at the lower edge of each plate, as
specified in 5C-3-3/Table 3
In the upper wing tank and the lower wing tank which is connected to the upper wing tank by trunks or
double sides, the nominal pressure, p, in such ballast tanks may be modified by the following equation:
p = pn − puh

In no case is p to be taken less than 2.06 N/cm2 (0.21kgf/cm2, 2.987 lbf/in2).

pn is nominal pressure in N/cm2 (kgf/cm2, lbf/in2) at the lower edge of each plate, as defined in 5C-3-3/Table 3.
puh is as defined in 5C-3-4/7.3.1.
f = permissible bending stress
= 0.85 Sm fy, in N/cm2 (kgf/cm2, lbf/in2)
Sm and fy are as defined in 5C-3-4/7.3.1.

23.3 Vertical and Horizontal Stiffeners

The net section modulus of each vertical or horizontal stiffener on transverse bulkheads, in association
with the effective plating to which it is attached, is to be not less than obtained from the following equation:
SM = M/fb in cm3 (in3)

M = 1000c1psl2/k in N-cm (kgf-cm, lbf-in)

where
k = 12 (12, 83.33)
c1 = 1.0 for horizontal stiffeners
= 1 + γl/10p for vertical stiffeners
γ = specific weight of the dry cargo or ballast as specified in Notes 4 and 5 in
5C-3-3/Table 3
s = spacing of vertical/horizontal stiffeners, in mm (in.)
l = span of stiffeners between effective supports, in m (ft)
p = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), at the stiffener considered, as defined
in 5C-3-4/23.1.
For vertical stiffeners, pressure is to be taken at the middle of span of each stiffener.

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Section 4 Initial Scantling Criteria 5C-3-4

fb = permissible bending stresses, in N/cm2 (kgf/cm2, lbf/ in2)

= 0.70 Sm fy for transverse bulkhead stiffeners
Sm and fy are as defined in 5C-3-4/7.5.

23.5 Horizontal Girder on Transverse Bulkhead

23.5.1 Section Modulus
The net section modulus of the horizontal girder with effective plating is to be not less than
obtained from the following equation:
SM = M/fb cm3 (in3)

M = 1000kc1ps l 2b N-cm (kgf-cm, lbf-in)

where
k = 10 (10, 26.9)
lb = span, in m (ft), of the horizontal girder, as shown in 5C-3-4/Figure 17
s = sum of the half lengths, in m (ft), of the vertical stiffeners supported on each
side of the horizontal girder
p = nominal pressure, in kN/m2 (tf/m2, Ltf/ft2), calculated at the midspan of the
horizontal girder under consideration, as specified in 5C-3-3/Table 3
fb = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.70 Sm fy
Sm and fy are as defined in 5C-3-4/7.3.1.
c1 may be obtained from the following equations:
For transverse bulkheads without vertical webs
c1 = 0.83
For transverse bulkheads with vertical webs
c1 = 0.83α2 for α < 0.5

= 0.531α2 + 0.0747 for 0.5 ≤ α ≤ 1.0

= 0.2243α + 0.3814 for α > 1.0
c1 is not to be taken less than 0.10 and need not be greater than 0.83.

α = (lvlb)[(I/Iv)(sv /s)]1/4

lv = span, in m (ft), of the vertical web, as shown in 5C-3-4/Figure 17

sv = sum of the half distance, in m (ft), between the vertical web under consideration
and the main vertical supporting members on each side of the vertical web
I, Iv = moments of inertia, in cm4 (in4), of the horizontal girder and the vertical web
clear of the end brackets
For determination of α, if more than one vertical web is fitted on the bulkhead, average values of
lv, sv and Iv are to be used when these values are not the same for each web.

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Section 4 Initial Scantling Criteria 5C-3-4

23.5.2 Sectional Area

The net sectional area of the web portion of the horizontal girder is to be not less than obtained
from the following equation:
A = F/fs cm2 (in2)

F = 1000ksc1 p(0.5l − he) N (kgf, lbf)

where
k = 1.0 (1.0, 2.24)
c1 = 1.0 for transverse bulkheads without vertical webs

= 0.85 α1/2 for transverse bulkheads with vertical webs, but not less than
0.3 and need not be greater than 1.0
l = span of the horizontal girder, in m (ft), as shown in 5C-3-4/Figure 17
he = length, in m (ft) of the end bracket, as shown in 5C-3-4/Figure 17
p, s and α are as defined in 5C-3-4/23.5.1.
fs = permissible shear stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.45 Sm fy
Sm and fy are as defined in 5C-3-4/7.3.1.

23.7 Vertical Web on Transverse Bulkhead

23.7.1 Section Modulus
The net section modulus of the vertical web in association with the effective plating is to be not
less than obtained from the following equation:
SM = M/fb cm3 (in3)

M = 100 kpsv l 2v N-cm (kgf-cm, lbf-in)

where
k = 83.33 (83.33, 22.4)
p = nominal pressure, in kN/m2 (tf/m2, Ltf/ft2), at the midspan of the vertical
web, as specified in 5C-3-3/Table 3
sv and lv are as defined in 5C-3-4/23.5.1 above.
fb = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.70 Sm fy
Sm and fy are as defined in 5C-3-4/7.3.1.
23.7.2 Sectional Area
The net sectional area of the web portion of vertical members is to be not less than obtained from
the following equation:
A = F/fs cm2 (in2)
F = 1000ksv p(0.5l − he) N (kgf, lbf)
where
k = 1.0 (1.0, 2.24)
l = span of vertical web, in m (ft), as shown in 5C-3-4/Figure 17
he = length of the end bracket, in m (ft), as shown in 5C-3-4/Figure 17

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Section 4 Initial Scantling Criteria 5C-3-4

p and sv are as defined in 5C-3-4/23.7.1.

fs = permissible shear stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.45 Sm fy
Sm and fy are as defined in 5C-3-4/7.3.1.

FIGURE 17
Transverse Bulkheads – Definitions of Spans

lb

he

TRANSVERSE BHD
ll

a. Horizontal Girder

DECK

he
TRANSVERSE BHD

l lt

he

DECK

b. Vertical Web

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-3-4

25 Corrugated Transverse Bulkheads(1995)

25.1 General (2001)

All vertically corrugated transverse bulkheads in cargo holds intended for dry cargoes, ballast or liquid
cargoes are to be designed in compliance with the requirements in this subsection, except that bulkheads
meeting the requirements in Appendix 5C-3-A5b need not comply with the requirements in 5C-3-4/25.7.
In all instances, the strength assessment criteria with respect to yielding, buckling and ultimate strength,
and fatigue, as specified in Section 5C-3-5, are to be complied with.
The scantlings of water-tight vertically corrugated bulkheads in dry cargo holds of single side skin construction,
intended to carry solid bulk cargoes having a density of 1.0 t/m3 (62.4 lb/ft3) or above, are to meet the
requirements for flooded condition in Appendix 5C-3-A5b of this part.
In general, the approximation equations given below are applicable to vertical corrugations with corrugation
angles φ (5C-3-4/Figure 11) within the range between 57 and 90 degrees. For corrugation angles less than
57 degrees and corrugation in the horizontal direction, direct calculations may be required.

25.3 Plating (1 July 1998)

The net thickness of the vertically corrugated plating is not to be less than t1, t2, t3 and t4, obtained from the
following equations for all anticipated service loading conditions.
t1 = 0.516k1a(pl/f1)1/2 in mm (in.) for flange and web plating
t2 = 0.42ak2(fy /E)1/2 in mm (in.) for flange plating

t3 = k(a/k3)(f3)1/210-3 in mm (in.) for flange plating

t4 = 100F/(d f4) in mm (in.) for web plating
but not less than 9.5 mm (0.37 in.)
where
k = 0.728(2.28, 0.605)
a = width of flange plating, in mm (in.) (5C-3-4/Figure 11)
c = width of web plating, in mm (in.) (5C-3-4/Figure 11)
d = depth of corrugation, in mm (in.) (5C-3-4/Figure 11)
φ = corrugation angle, (5C-3-4/Figure 11)
k1 = (1 − c/a + c2/a2)1/2
k2 = f2/(0.73fy)
k3 = 7.65 − 0.26(c/a)2
F = shear force, in N (kgf, lbf), imposed on the web plating at the lower end of
corrugation span
= k4sl(0.375pl + 0.125pu)
k4 = 10 (10, 12)
s = spacing of corrugation, in mm (in.)
= a + c cos φ, (5C-3-4/Figure 11)
l = span of corrugation, in m (ft), taken as the distance between the lower and upper
stools at centerline. If there is no lower stool, the span is to be taken as the distance
between inner bottom and upper stool at centerline. If there is no upper stool, the span
is to be taken as the distance between lower stool and upper deck at centerline,
(5C-3-4/Figure 18)

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pl, pu = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), at the lower and upper ends of span,
respectively, as specified in 5C-3-3/Table 3
f1 = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.90 Sm fy
f2 = maximum vertical bending stress in the flange at the mid-depth of corrugation span to
be calculated from 5C-3-4/25.5 below, in N/cm2 (kgf/cm2, lbf/in2)
f3 = maximum vertical bending stress in the flange at the lower end of corrugation span to
be calculated from 5C-3-4/25.5 below, in N/cm2 (kgf/cm2, lbf/in2)
f4 = pemissible shear stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.40 Sm fy
E, Sm and fy are as defined in 5C-3-4/7.3.
The plate thickness, as determined above based on the maximum anticipated pressures, is to be generally
maintained throughout the entire corrugated bulkhead, except that the net thickness of plating above 0.7 of
span l from the top of the lower stool may be reduced by 20%.

25.5 Stiffness of Corrugation

25.5.1 Depth/Length Ratio
The depth/length ratio (d/l) of the corrugation is to be not less than 1/15 for cargo holds intended
for ballast or liquid cargoes and 1/17.5 for all other cargo holds where d and l are as defined in
5C-3-4/25.3 above.
25.5.2 Section Modulus
The net section modulus for any unit corrugation is to be not less than obtained from the following
equation for all anticipated service loading conditions.
SM = M/fb cm3 (in3)

M = 1000Ci ps l 2o /k N-cm (kgf-cm, lbf-in)

where
k = 12 (12, 83.33)
lo = nominal length of the corrugation, in m (ft), measured from the mid-depth of
the lower stool, or the inner bottom if there is no lower stool, to the mid-
depth of the upper stool or the deck at centerline if there is no upper stool
p = (pu + pl)/2, N/cm2 (kgf/cm2, lbf/in2)

fb = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)

= 0.90 Sm fy , for lower end of corrugation span l

= ce fy ≤ 0.90Sm fy , for the mid l/3 region of the corrugation

ce = 2.25/β − 1.25/β2 for β ≥ 1.25

= 1.0 for β < 1.25

β = (fy /E)1/2 a/tf
tf = net thickness of corrugation flange
Ci = the bending moment coefficients as given below

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Section 4 Initial Scantling Criteria 5C-3-4

Values of Ci (All Bulkheads with Lower Stool)

Location Lower End of Span l Mid-depth Upper End of Span l
Ballast Tank or C1 Cm1 0.50Cm1
Liquid Cargo Holds
(with upper stool)
Dry Cargo Holds
(with upper stool) C2 Cm2 0.60Cm2
(without upper stool) C3 Cm3 0.10Cm3

Values of Ci (Dry Cargo Hold Bulkhead without

Lower Stool for Vessels Shorter than 190 m in Length)
Location Lower End of Span l Mid-depth Upper End of Span l
Dry Cargo Holds C4 Cm4 0.50Cm4
(with upper stool)

C1 = a1 + b1(kAd /Ld)1/2 ≥ 0.6,

where a1 = 0.89 − 0.152/Rb,

b1 = -0.37 + 0.102/Rb
Cm1 = am1 + bm1(kAd /Ld)1/2,
where am1 = 0.47 + 0.08/Rb,

bm1 = -0.05 − 0.067/Rb

C2 = a2 + b2(kAd /Ld)1/2,

where a2 = 1.08 − 0.028/Rb,

b2 = -0.37 + 0.026/Rb
Cm2 = am2 + bm2(kAd /Ld)1/2,
where am2 = 0.52 + 0.014/Rb,

bm2 = -0.07 − 0.014/Rb

C3 = 1.03 − 0.035/Rb
Cm3 = 0.51 + 0.014/Rb

C4 = a4 + b4(kAd /Ld)1/2,

where a4 = l.9 − 0.209Ra − 0.504/Ra,

b4 = 0.06 − 0.079Ra − 0.173/Ra

Cm4 = am4 + bm4(kAd /Ld)1/2,
where am4 = -0.1 + 0.208Ra + 0.484/Ra,
bm4 = -0.48 + 0.069Ra + 0.173/Ra
Rb = kHs(Bc + Bs)(1 + Lh /Lb + 0.5Hb /Lh)/(2Lb)
Ra = k(1 + Lh /Lb + 0.5Hb /Lh)

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Section 4 Initial Scantling Criteria 5C-3-4

Ad = cross section area, in m2 (ft2), enclosed by the outside lines of upper stool
Bc = width of the bottom stool, in m (ft), at the top (5C-3-4/Figure 18)
Bs = width of the bottom stool, in m (ft), at the inner bottom level (5C-3-4/Figure 18)
Hb = double bottom height, in m (ft)
Hs = height of the bottom stool, in m (ft), from the inner bottom to the top
(5C-3-4/Figure 18)
Lb = transverse distance, in m (ft), between hopper tanks at the inner bottom level
(5C-3-4/Figure 18)
Ld = transverse distance, in m (ft), between upper wing tanks at the deck level
(5C-3-4/Figure 18)
Lh = longitudinal distance, in m (ft), between bottom stools in the loaded holds at
the inner bottom level (5C-3-4/Figure 18)
k = 1 (1, 3.281)
a, l, s, pu and pl are as defined in 5C-3-4/25.3 above.
E is as defined in 5C-3-4/7.3.1.
Sm and fy are as defined in 5C-3-4/7.
The developed net section modulus SM may be obtained from the following equation, where a, c,
d, tf (net) and tw (net), all in cm (in.), are as indicated in 5C-3-4/Figure 11.
SM = d(3atf + ctw)/6 cm3 (in3)

25.7 Flooded Conditions

Unless otherwise specified in 5C-3-4/25.1, the plate thickness and section modulus of the vertical corrugation
of bulkheads bounding any dry cargo hold are to be in accordance with the following requirements.
25.7.1 Flooded Condition
Unless a direct calculation is carried out to determine the most probable pressures imposed on the
corrugated bulkhead for a simulated flooded condition, an equivalent pressure distribution
corresponding to 70% of the pressure obtained for a full ballast hold as specified in 5C-3-3/Table 3
is to be used for this purpose.
25.7.2 Plate Thickness (1 July 1998)
The net thickness of the flange panels and web panels below 0.7 of span l from the top of the
lower stool is not to be less than t2 and t4, respectively, as specified in 5C-3-4/25.3 above with the
flooded pressure defined in 5C-3-4/25.7.1 above and bending moment coefficient defined in
5C-3-4/25.7.3(b) below. In determination of t4, the permissible shear stress of 0.50 Sm fy is to be used.
25.7.3 Section Modulus and Ultimate Bending Moment (1 July 1998)
The net section modulus of the corrugation obtained from 5C-3-4/25.5 above is to be increased, as
specified below.
25.7.3(a) The net section modulus for any unit corrugation below 0.7 of span l from the top of
the lower stool is not to be less than SM required in 5C-3-4/25.5 for the mid-depth region with the
flooded pressure defined in 5C-3-4/25.7.1 above and bending moment coefficients given in the
table in 5C-3-4/25.7.3(b) below. The permissible bending stress is as defined as follows:
fb = ce fy ≤ 0.95Sm fy
ce, fy and Sm are as defined in 5C-3-4/25.5 above.

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-3-4

25.7.3(b) The calculated maximum bending moment, M, at the lower end and mid-depth of the
corrugation is not to be greater than 90% of the ultimate bending moment, Mu, defined as follows:

Mu = 0.25d(2atf + ctw)10-3 Sm fy N-cm (kgf-cm, lbf-in)

For the calculation of M for 5C-3-4/25.7.3(a) and 5C-3-4/25.7.3(b) above, the following bending
moment coefficients, Ci may be used.

Dry Cargo Hold Bulkhead with Lower Stool

Location Lower End of Span l Mid-depth Upper End of Span l
Dry Cargo Holds
(with upper stool) C1 Cm1 0.50Cm1
(without upper stool) C5 Cm5 0.20Cm5

Dry Cargo Hold Bulkhead without Lower Stool

for Vessels Shorter than 190m in Length
Location Lower End of Span l Mid-depth Upper End of Span l
Dry Cargo Holds C6 Cm6 0.50Cm6
(with upper stool)

where
C5 = 1.01 − 0.166/Rb
Cm5 = 0.52 + 0.085/Rb

C6 = a6 + b6(kAd /Ld)1/2,

where a6 = 1.81 − 0.118Ra − 0.266/Ra,

b6 = -0.55 − 0.105Ra − 0.224/Ra

Cm6 = am6 + bm6(kAd /Ld)1/2,
where am6 = 0.66 + 0.041Ra + 0.085/Ra,
bm6 = -0.62 + 0.031Ra + 0.079/Ra
All other parameters are as defined in 5C-3-4/25.5 above.

25.9 Bulkhead Lower Stool (2004)

The height of the lower stool is generally to be not less than three (3) times the depth of corrugation. The
net thickness and material of the stool top plate is not to be less than that required for the bulkhead plating.
The net thickness and material of the upper part of the vertical or sloping stool side plate, within the region
of one corrugation flange width from the stool top, is not to be less than those required to meet the
bulkhead stiffness requirement for the flange at the lower end of corrugation. The net thickness of the stool
side plating and the net section modulus of the stool side stiffeners are to be not less than those required for
plane transverse bulkhead plating and stiffeners, in 5C-3-4/23.1 and 5C-3-4/23.3 with the pressure
specified in 5C-3-4/25.7.1 nor, where applicable, those required by 5C-3-A5b/13. The ends of the stool
side vertical stiffeners are to be attached to brackets at the upper and lower ends of the stool.
The extension of the top plate beyond the corrugation is to be not less than the as-built flange thickness of
the corrugation. See 5C-3-4/Figure 20. Proper brackets and diaphragms are to be provided in the stool to
effectively support the panels of the corrugated bulkhead. The width of the stool at the inner bottom is to
be not less than 2.5 times the mean depth of the corrugation. The stool bottom is to be positioned in line
with double bottom floors. Scallops in the brackets and diaphragms in way of the top and bottom
connections to the plate and in the double bottom floors or girders are to be avoided.

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-3-4

For vessels less than 190 meters in length, the lower stool may be omitted in dry cargo holds. In that case
the strength of the corrugated bulkhead is to comply with the requirements in 5C-3-4/25.5 for the bulkhead
without lower stool. When no lower stool is fitted, the corrugation flanges are to be in line with the
supporting floors and cut-outs in the floors for inner bottom longitudinals are to be closed by collar plates.
The thickness and material properties of these floors are to be at least equal to those provided for the
corrugation flanges. If the stool is fitted for vessels less than 190 meters in length, the arrangements and
scantlings of the stool are to comply with the requirements of this Paragraph.

25.11 Bulkhead Upper Stool (2004)

The upper stool, where fitted, is to have a height measured at the inboard side of the upper wing tank,
generally not less than two (2) times the depth of corrugation, and is to be properly supported by girders or
deep brackets between the adjacent hatch-end beams.
The width of the stool bottom plate is generally to be the same as that of the lower stool top plate. The net
thickness of the stool bottom plate is generally to be not less than that required for the upper part of the
bulkhead plating, and the net thickness of the lower part of the stool side plate is to be not less than 80% of
that required for the stool bottom plate. The net thickness of the stool side plating and the net section
modulus of the stool side stiffeners are to be not less than those required for plane transverse bulkhead
plating and stiffeners, in 5C-3-4/23.1 and 5C-3-4/23.3, with the pressure specified in 5C-3-4/25.7.1 nor,
where applicable, those required by 5C-3-A5b/13. The ends of the stool side stiffeners are to be attached to
brackets at the upper and lower ends of the stool. Brackets or diaphragms are to be fitted to effectively
support the web panels of the corrugated bulkhead. Scallops in the brackets and diaphragms in way of the
connection to the stool bottom plate are to be avoided.

25.13 Bulkhead Stool Alignment

Stool side plating is to align with the corrugation flanges.
Stool side plating is not to be knuckled anywhere between the inner bottom plating and the stool top.
When no upper stool is fitted, care is to be exercised to provide proper backing structure for the corrugation
flanges at the deck level. This may generally be accomplished by fitting two heavy transverse beams in
line with the corrugation flanges.
Stool side vertical stiffeners and their brackets in lower stool are to align with the inner bottom longitudinals
to provide appropriate load transmission between these stiffening members.

25.15 Bulkhead End Connection (2004)

The structural arrangements and welding at the ends of corrugations are to be designed to develop the
required strength of the corrugated bulkhead. Shedder plates (slanting plates) are to be fitted at the lower
end connection of the corrugation to the lower stool. It is recommended that the upper end of the
corrugation be connected to the upper stool or the upper deck with brackets or gussets arranged in line with
corrugation flanges. For floor plates directly below the stool side plating or directly below the corrugation
flange, if no stool is provided, cut-outs for inner bottom longitudinals are to be closed by collar plates.
Welded connections are to comply with Section 3-2-19, except as modified in the following paragraphs.
At the lower end, corrugations are to be connected to the stool top plate by full penetration welding. The
stool side plating is to be connected to the stool top plate and inner bottom plating by either full penetration
or deep penetration welds. The plating of the lower stool and supporting floors is to be connected to the
inner bottom plating by full or “deep penetration welding” (see 5C-3-4/Figure 21). If no lower stool is
fitted, corrugations are to be connected to the inner bottom plating by full penetration welding and the
plating of the supporting floors is to be connected to the inner bottom plating by full or “deep penetration
welding” (see 5C-3-4/Figure 21). The double bottom girders in a cargo hold intended for the carriage of
ballast water at sea are to be connected to the floors and the inner bottom plating in way of the side plating
of the lower stool by full penetration welding. (See Figure below.)

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-3-4

Lower Stool
Side Plate

Full Penetration Weld

* * *
* * * * * *

* Min. 150 mm (6 in.)

Solid Floors Bottom Side Girders
(Intercostal Member) (Continuous Member)

At the upper stool, the welds connecting the bulkhead and stool within 10% of the depth of the corrugation
from the outer surface of the corrugation, d1, are to have double continuous welds with fillet size not less
than 0.7 times the thickness of the bulkhead plating or equivalent penetration welds (see 5C-3-4/Figure 19).
Shedder plates are to be welded to the corrugations and stool top plates by one-sided penetration welds or
equivalent. Gusset plates are to be welded to the stool top plate with full penetration welds and to the
corrugations by one-sided penetration welds or equivalent.

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-3-4

FIGURE 18
Definition of Parameters for Corrugated Bulkhead
Ld

Lb

L
C

Ad

lo l

Bc

Hs

Hb Bs Lh

FIGURE 19
Corrugated Bulkhead End Connections
Bottom of Upper Stool

0.7t (t = ACTUAL)

d1
0.1d1

t (ACTUAL)

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 4 Initial Scantling Criteria 5C-3-4

FIGURE 20
Extension of Lower Stool Top Plate (2002)
corrugation
flange

tf
corrugation
flange
d
tf
tf

Stool top plate

d
Stool top plate

d ≥ tf
d

/
/
* tf: As-Built Flange Thickness

FIGURE 21
Full/Deep Penetration Welding (2003)

T T

f
f
α
α α

Root Face (f): (for full penetration weld) 0 mm ≤ f ≤ 3 mm (with back gouging)
(for deep penetration weld) 3 mm ≤ f ≤ T/3 mm

Groove Angle ( α) 40º to 60º

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PART Section 5: Total Strength Assessment

5C
CHAPTER 3 Vessels Intended to Carry Ore or Bulk Cargoes
(150 meters (492 feet) or more in Length)

SECTION 5 Total Strength Assessment

1 General Requirements

1.1 General (1996)

In assessing the adequacy of the structural configuration and the initially selected scantlings, the strength
of the hull girder and the individual structural member or element is to be in compliance with the failure
criteria specified in 5C-3-5/3 below. In this regard, the structural response is to be calculated by performing a
structural analysis as specified in 5C-3-5/9 or by other equivalent and effective means. Due consideration
is to be given to structural details as specified in 5C-3-4/1.5.

1.3 Loads and Load Cases (1996)

In the determination of the structural response, the combined load cases given in 5C-3-3/9.3 are to be
considered together with impact loads specified in 5C-3-3/11. Vibratory hull-girder and other loads as
specified in 5C-3-3/13 are also to be considered as necessary.

1.5 Stress Components (1996)

The total stresses in stiffened plate panels are divided into the following three categories.
1.5.1 Primary
Primary stresses are those resulting from hull-girder bending. The primary bending stresses may
be determined by simple beam theory using the specified total vertical and horizontal bending
moments and the effective net hull-girder section modulus at the section considered. These
primary stresses, designated by fL1 (fL1V, fL1H for vertical and horizontal bending, respectively),
may be regarded as uniformly distributed across the thickness of plate elements at the same level,
measuring from the relevant neutral axis of the hull girder.
1.5.2 Secondary
Secondary stresses are those resulting from bending of large stiffened panels between longitudinal
and transverse bulkheads due to local loads in an individual cargo or ballast hold.
The secondary bending stresses, designated by fL2 or fT2, are to be determined by performing a 3D
FEM analysis as outlined in this section.
For stiffened hull structures, there is another secondary stress due to the bending of longitudinals
or stiffeners with the associated plating between deep supporting members or floors. The latter
secondary stresses are designated by f L*2 or f T*2 , and may be approximated by simple beam
theory.
The secondary stresses, fL2, fT2, f L*2 or f T*2 , may be regarded as uniformly distributed in the flange
plating and face plates.
1.5.3 Tertiary
Tertiary stresses are those resulting from the local bendings of plate panels between stiffeners. The
tertiary stresses, designated by fL3 or fT3, can be calculated from classic plate theory. These stresses
are referred to as point stresses at the surface of the plate.

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Section 5 Total Strength Assessment 5C-3-5

3 Yielding Criteria

3.1 General
The calculated stresses in the hull structure are to be within the limits given below for all of the combined
load cases specified in 5C-3-3/9.3.

3.3 Structural Members and Elements

For all structural members and elements, such as longitudinals/stiffeners, web plates and flanges, the
combined effects of all of the calculated stress components are to satisfy the following limits:
fi ≤ Sm fy
where
fi = stress intensity

= ( f L2 + f T2 − fL fT + 3 f LT
2 1/2
) N/cm2 (kgf/cm2, lbf/in2)
fL = calculated total in-plane stress in the longitudinal direction including primary and
secondary stresses

= fL1 + fL2 + f L*2 , N/cm2 (kgf/cm2, lbf/in2)

fL1 = direct stress due to the primary (hull girder) bending, N/cm2 (kgf/cm2, lbf/in2)
fL2 = direct stress due to the secondary bending between bulkheads in the longitudinal
direction, N/cm2 (kgf/cm2, lbf/in2)
f L*2 = direct stress due to local bending of longitudinal between transverses in the
longitudinal direction, N/cm2 (kgf/cm2, lbf/in2)
fT = calculated total direct stress in the transverse/vertical direction, including secondary
stresses

= fT1 + fT2 + f T*2 N/cm2 (kgf/cm2, lbf/in2)

fLT = calculated total in-plane shear stress, N/cm2 (kgf/cm2, lbf/in2)
fT1 = direct stress due to sea and cargo loads in the transverse/vertical direction, N/cm2
(kgf/cm2, lbf/in2)
fT2 = direct stress due to the secondary bending between bulkheads in the
transverse/vertical direction, N/cm2 (kgf/cm2, lbf/in2)
f T*2 = direct stress due to local bending of stiffeners in the transverse/vertical direction,
N/cm2 (kgf/cm2, lbf/in2)
fy = specified minimum yield point, N/cm2 (kgf/cm2, lbf/in2)
Sm = strength reduction factor, as defined in 5C-3-4/7.3.1
For this purpose, f L*2
and f T*2 in the flanges of longitudinals and stiffeners, at the ends of span may be
obtained from the following equation.

f L*2 ( f T*2 ) = 0.071spl2/SML (SMT) N/cm2 (kgf/cm2, lbf/in2)

where
s = spacing of longitudinals (stiffeners), in cm (in.)
l = unsupported span of the longitudinal (stiffener), in cm (in.)
p = net pressure load, in N/cm2 (kgf/cm2, lbf/in2), for the longitudinal (stiffener)
SML (SMT) = net section modulus, in cm3 (in3), of the longitudinal (stiffener)

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Section 5 Total Strength Assessment 5C-3-5

3.5 Plating
For plating subject to both in-plane and lateral loads, the combined effects of all the calculated stress
components are to satisfy the limits specified in 5C-3-5/3.3 with fL and fT modified as follows:

fL = fL1 + fL2 + f L*2 + fL3 N/cm2 (kgf/cm2, lbf/in2)

fT = fT1 + fT2 + f T*2 + fT3 N/cm2 (kgf/cm2, lbf/in2)

where
fL3, fT3 = plate bending stresses between stiffeners in the longitudinal and transverse directions,
respectively, and may be approximated as follows.
fL3 = kL p(s/tn)2 N/cm2 (kgf/cm2, lbf/in2)

fT3 = kT p(s/tn)2 N/cm2 (kgf/cm2, lbf/in2)

kL = 0.182 or 0.266 for stiffeners in the longitudinal or transverse direction, respectively
kT = 0.266 or 0.182 for stiffeners in the longitudinal or transverse direction, respectively
p = lateral pressures for the combined load case considered (see 5C-3-3/9), in N/cm2
(kgf/cm2, lbf/ in2)
s = spacing of longitudinals or stiffeners, in mm (in.)
tn = net plate thickness, in mm (in.)

fL1, fL2, f L*2 , fT1, fT2 and f T*2 are as defined in 5C-3-5/3.3.

5 Buckling and Ultimate Strength Criteria (1996)

5.1 General
5.1.1 Approach
The strength criteria given here correspond to either serviceability (buckling) state limits or
ultimate state limits for structural members and panels, according to the intended functions and
buckling resistance capability of the structure. For plate panels between stiffeners, buckling in the
elastic range is acceptable, provided the ultimate strength of the structure satisfies the specified
design limits. The critical buckling stresses and ultimate strength of structures may be determined
based on either well-documented experimental data or a calibrated analytical approach. When a
detailed analysis is not available, the equations given in Appendix 5C-3-A2 may be used to assess
the buckling strength.
For vertically corrugated transverse bulkheads, the buckling and ultimate strength is to be in
compliance with the criteria given in 5C-3-5/5.11 below. In this case, the buckling of the flange
and web panels is not acceptable for the load cases specified in 5C-3-3/9.
5.1.2 Buckling Control Concepts
The strength criteria in 5C-3-5/5.3 through 5C-3-5/5.13 are based on the following assumptions
and limitations with respect to buckling control in design.
5.1.2(a) The buckling strength of longitudinals and stiffeners is generally greater than that of the
plate panels they support.
5.1.2(b) All longitudinals with the associated effective plating are to have moments of inertia not
less than io given in 5C-3-A2/11.1.
5.1.2(c) The main supporting members, including transverses, girders and floors, with the
effective associated plating are to have moments of inertia not less than Is given in 5C-3-A2/11.5.
In addition, tripping (e.g., torsional instability) is to be prevented as specified in 5C-3-A2/9.5.

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5.1.2(d) Face plates and flanges of girders, longitudinals and stiffeners are proportioned such that
local instability is prevented. (See 5C-3-A2/11.7)
5.1.2(e) Webs of longitudinals and stiffeners are proportioned such that local instability is
prevented. (See 5C-3-A2/11.9).
5.1.2(f) Webs of girders, floors and transverses are designed with proper proportions and stiffening
systems to prevent local instability. Critical buckling stresses of the webs may be calculated from
equations given in 5C-3-A2/3.
For structures which do not satisfy these assumptions, a detailed analysis of the buckling strength
using an acceptable method is to be submitted for review.

5.3 Plate Panels

5.3.1 Buckling State Limit
The buckling state limit for plate panels between stiffeners is defined by the following equation.
(fLb/Rl fcL)2 + (fTb/Rt fcT)2 + (fLT/fcLT)2 ≤ 1.0
where
fLb = fL1 + fL2 = calculated total compressive stress in the longitudinal direction for
the plate, in N/cm2 (kgf/cm2, lbf/in2), induced by bending of the hull girder
and large stiffened panels between bulkheads
fTb = fT1 + fT2 = calculated total compressive stress in the transverse/vertical
direction, in N/cm2 (kgf/cm2, lbf/in2)
fLT = calculated total in-plane shear stress, in N/cm2 (kgf/cm2, lbf/in2)
fcL, fcT and fcLT are the critical buckling stresses corresponding to uniaxial compression in the
longitudinal, transverse/vertical directions and edge shear, respectively, in N/cm2 (kgf/cm2, lbf/in2),
and may be determined from the equations given in 5C-3-A2/3.
Rl, Rt = reduction factors accounting for lateral load effects, and may be
approximated by:
Rl = 1.0, Rt = 1.0 − 0.45 (q − 0.5), q ≥ 0.5 for plating longitudinally stiffened
Rt = 1.0, Rl = 1.0 − 0.45 (q − 0.5), q ≥ 0.5 for plating transversely stiffened
q = lateral load parameter = pn(s/tn)4/π2E
pn = lateral pressure for the combined load case considered (see 5C-3-3/9), in
N/cm2 (kgf/cm2, lbf/in2)
s = longitudinal spacing, in mm (in.)
tn = net thickness of the plate, in mm (in.)
E = Young’s modulus, in N/cm2 (kgf/cm2, lbf/in2), for steel 2.06 × 107
(2.10 × 106, 30 × 106)
Rl, Rt are not to be taken less than 0.50.
fL, fT and fLT are to be determined for the panel in question under the load cases specified in 5C-3-3/9,
including the primary and secondary stresses as defined in 5C-3-5/3.1.
5.3.2 Effective Width
When the buckling state limit specified in 5C-3-5/5.3.1 above is not satisfied, the effective width
bwL or bwT of the plating given below is to be used instead of the full width between longitudinals,
s, for determining the effective hull-girder section modulus SMe, specified in 5C-3-5/5.13 and also
for verifying the ultimate strength as specified in 5C-3-5/5.3.3 below. When the buckling state
limit in 5C-3-5/5.3.1 is satisfied, the full width between longitudinals, s, may be used as the effective
width bwL for verifying the ultimate strength of longitudinals and stiffeners specified in 5C-3-5/5.5
and for determining the effective hull-girder section modulus SMe specified in 5C-3-5/5.13 below.

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Section 5 Total Strength Assessment 5C-3-5

5.3.2(a) For long plate (compression on the short edges)

bwL/s = C

C = 2.25/β − 1.25/β2 for β ≥ 1.25

= 1.0 for β < 1.25
β = (fy /E)1/2 s/tn
s, tn and E are as defined in 5C-3-5/5.3.1 above.
fy = specified minimum yield point of the material, in N/cm2 (kgf/cm2, lbf/in2)
5.3.2(b) For wide plate (compression on the long edges)
bwt/l = Cs/l + 0.115(1 − s/l)(1 + 1/β2)2 ≤ 1.0
where
l = spacing of transverses/girders, in cm (in.)
s = longitudinal spacing, in cm (in.)
C, β are as defined in 5C-3-5/5.3.2(a) above
5.3.3 Ultimate Strength
The ultimate strength of a plate panel between stiffeners is to satisfy all of the following equations:
(fLb /RlfuL)2 + (fLT /fuLT)2≤ Sm

(fTb /Rt fuT)2 + (fLT /fuLT)2 ≤ Sm

(fLb /RlfuL)2 + (fTb /Rt fuT)2 − η(fLb /RlfuL)(fTb /Rt fuT) + (fLT /fuLT) ≤ Sm
where
fLb, fTb, fLT, Rl and Rt are as defined in 5C-3-5/5.3.1 above.
Sm is as defined in 5C-3-4/7.3.1.

η = 1.5 − β/2 ≥ 0
β is as defined in 5C-3-5/5.3.2 above.
fuL, fuT and fuLT are the ultimate strengths with respect to uniaxial compression and edge shear,
respectively, and may be obtained from the following equations, except that they need not be
taken less than the corresponding critical buckling stresses specified in 5C-3-5/5.3.1 above.
fuL = fy bwL /s ≥ fcL, fuT = fy bwT /l ≥ fcT for plating longitudinally stiffened

fuT = fy bwT /l ≥ fcL, fuT = fy bwL /s ≥ fcT for plating transversely stiffened

fuLT = fcLT + 0.5(fy − 3 fcLT)/(1 + α + α2)1/2 ≥ fcLT

where
α = l/s
fy, bwL, bwT, s, l, fcL, fcT and fcLT are as defined in 5C-3-5/5.3.1 and 5C-3-5/5.3.2 above.
For assessing the ultimate strength of plate panels between stiffeners, special attention is to be
paid to the longitudinal bulkhead plating in the regions of high hull girder shear forces and the
bottom and inner bottom plating in the mid region of cargo holds subject to bi-axial compression.

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Section 5 Total Strength Assessment 5C-3-5

5.5 Longitudinals and Stiffeners

5.5.1 Beam-Column Buckling State Limits and Ultimate Strength (2002)
The buckling state limits for longitudinals and stiffeners are considered as the ultimate state limits
for these members and are to be determined as follows:
fa /( fca Ae /A) + mfb / fy ≤ Sm
where
fa = nominal calculated compressive stress

= P/A, N/cm2 (kgf/cm2, lbf/in2)

P = total compressive load, N (kgf, lbf)
fca = critical buckling stress, as given in 5C-3-A2/5.1, N/cm2 (kgf/cm2, lbf/in2)

A = total net sectional area, cm2 (in2)

= As + stn
As = net sectional area of the longitudinal, excluding the associated plating, cm2 (in2)

Ae = effective net sectional area, cm2 (in2)

= As + bwL tn
bwL = effective width, as specified in 5C-3-5/5.3.2(a) above

E = Young’s modulus, 2.06 × 107 N/cm2 (2.1 × 106 kgf/cm2, 30 × 106 lbf/in2) for
steel
fy = minimum specified yield point of the longitudinal or stiffener under
consideration, N/cm2 (kgf/cm2, lbf/in2)
fb = bending stress, N/cm2 (kgf/cm2, lbf/in2)
= M/SMe
M = maximum bending moment induced by lateral loads
= cm psl2/12 N-cm (kgf-cm, lbf-in)
cm = moment adjustment coefficient, and may be taken as 0.75

p = lateral pressure for the region considered, N/cm2 (kgf/cm2, lbf/in2)

s = spacing of the longitudinals, cm (in.)
SMe = effective section modulus of the longitudinal at flange, accounting for the
effective breadth, be, cm3 (in3)
be = effective breadth, as specified in 5C-3-4/Figure 4, line b
m = amplification factor
= 1/[1 − fa /π2E(r/l)2] ≥ 1.0
Sm is as defined in 5C-3-4/7.3.1.

r and l are as defined in 5C-3-A2/5.1.

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Section 5 Total Strength Assessment 5C-3-5

5.5.2 Torsional-Flexural Buckling State Limit (2002)

In general, the torsional-flexural buckling state limit of longitudinals and stiffeners is to satisfy the
ultimate state limits given below:
fa/(fctAe/A) ≤ Sm
where
fa = nominal calculated compressive stress in N/cm2 (kgf/cm2, lbf/in2), as defined
in 5C-3-5/5.5.1 above
fct = critical torsional-flexural buckling stress in N/cm2 (kgf/cm2, lbf/in2), and
may be determined by equations given in 5C-3-A2/5.3
Ae and A are as defined in 5C-3-5/5.5.1 above and Sm is as defined in 5C-3-4/7.3.1.

5.7 Stiffened Panels

5.7.1 Large Stiffened Panels Between Bulkheads
For a vessel under the assumptions made in 5C-3-5/5.1.2 above with respect to the buckling
control concepts, the large stiffened panels of the double bottom and wing tank structures between
transverse bulkheads should automatically satisfy the design limits, provided each individual plate
panel and longitudinally and uniaxially stiffened panel satisfy the specified ultimate state limits.
Assessments of the buckling state limits are to be performed for large stiffened panels of the deck
structure, side shell and plane transverse bulkheads. In this regard, the buckling strength is to
satisfy the following condition for uniaxially or orthogonally stiffened panels.
(fL1/fcL)2 + (fT1/fcT)2 ≤ Sm
where
fL1, fT1 = the calculated average compressive stresses in the longitudinal and
transverse/vertical directions respectively, in N/cm2 (kgf/cm2, lbf/in2)
fcL, fcT = the critical buckling stresses for uniaxial compression in the longitudinal and
transverse direction, respectively, and may be determined in accordance with
5C-3-A2/7, in N/cm2 (kgf/cm2, lbf/in2)
Sm = strength reduction factor, as defined in 5C-3-4/7.3.1

5.7.2 Uniaxially Stiffened Panels between Transverses and Girders

The buckling strength of uniaxially stiffened panels between deep transverses and girders is also
to be examined in accordance with the specifications given in 5C-3-5/5.7.1 by replacing fL1 and fT1
with fLb and fTb, respectively. fLb and fTb are as defined in 5C-3-5/5.3.1.

5.9 Deck Girders and Webs

5.9.1 Buckling Criteria
In general, the stiffness of the web stiffeners along the depth of the web plating is to be in
compliance with the requirements in 5C-3-A2/11.3. Web stiffeners which are oriented parallel to
and near the face plate, thus subject to axial compression, are also to satisfy the limits specified in
5C-3-5/5.5, considering the combined effect of the compressive and bending stresses in the web.
In this case, the unsupported span of these parallel stiffeners may be taken between tripping
brackets, as applicable.
The buckling strength of the web plate between stiffeners and flange/face plate is to satisfy the
limits specified below.
5.9.1(a) For Web Plate
(fLb /fcL)2 + (fb /fcb)2 + (fLT /fcLT)2 ≤ Sm

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where
fLb = calculated uniform compressive stress along the length of the girder, in
N/cm2 (kgf/cm2, lbf/in2)
fb = calculated ideal bending stresses, in N/cm2 (kgf/cm2, lbf/in2)

fLT = calculated total in-plane shear stress, in N/cm2 (kgf/cm2, lbf/in2)

fLb, fb and fLT are to be calculated for the panel in question under the combined load cases specified
in 5C-3-3/9.3.
fcL, fcb and fcLT are critical buckling stresses with respect to uniform compression, ideal bending
and shear, respectively, and may be determined in accordance with Appendix 5C-3-A2. Sm is as
defined in 5C-3-4/7.3.1.
In the determination of fcL and fcLT, the effects of openings are to be considered.
5.9.1(b) For Face Plate and Flange. The breadth to thickness ratio of face plate and flange is to
satisfy the limits given in 5C-3-A2/11.
5.9.1(c) For Large Brackets and Sloping Webs. The buckling strength is to satisfy the limits
specified above for web plate.
5.9.2 Tripping
Tripping brackets are to be provided in accordance with 5C-3-A2/9.5.

5.11 Corrugated Bulkheads

5.11.1 Local Plate Panels
5.11.1(a) Buckling Criteria. The buckling strength of the flange and web plate panels are to
satisfy the conditions specified below:
(fLb /Rl fcL)2 + (fTb /Rt fcT)2 + (fLT /fcLT)2 ≤ Sm for flange panels

(fLb /Rl fcL)2 + (fb /fcb)2 + (fLT /fcLT)2 ≤ Sm for web panels
All the parameter definitions and calculations are as specified in 5C-3-5/5.3.1 and 5C-3-5/5.9.1(a)
above, except that fLb is the average compressive stress at the upper and lower ends of the
corrugation and an average value of fLT and fb calculated along the entire length of the panel is to
be used in the above equation. When a direct calculation is not available, the fLT in the flange
panels may be taken as one half of that in the web panels and fTb for the flange panels may be
approximated by
fTb = p(c + a cos φ)/(2t sin φ)
where
p = nominal pressure specified in Section 5C-3-3 for the corrugated bulkhead, in
N/cm2 (kgf/cm2, lbf/in2)
a = width of flange panel, in cm (in.)
c = width of web panel, in cm (in.)
φ = corrugation angle, in degrees
t = net thickness of the flange panel, in cm (in.)
5.11.1(b) Ultimate Strength. The ultimate strength of flange panels in the middle third region of
the depth is to satisfy the following criteria for all service load cases and the specified flooded
conditions. In this case, a part of the flange panel with a length of three times the panel width, a,
covering the worst bending moments in the mid-depth region is to be considered.

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Section 5 Total Strength Assessment 5C-3-5

(fLb /fuL)2 + (fTb /fuT)2 ≤ Sm

where
fLb = the calculated average compressive bending stress in the region within 3a in
length, N/cm2 (kgf/cm2, lbf/in2)
fTb = horizontal compressive stresses, as specified in 5C-3-5/5.11.1(a) above
fuL and fuT may be calculated in accordance with 5C-3-5/5.3.3.

5.11.2 Unit Corrugation

Any unit corrugation of the bulkhead may be treated as a beam column and is to satisfy the
buckling criteria (same as the ultimate strength) specified in 5C-3-5/5.5.1. The ultimate bending
stress is to be determined in accordance with 5C-3-A2/5.5.
5.11.3 Entire Corrugation
The buckling strength of the entire corrugation is to satisfy the equation given in 5C-3-5/5.7.1
with respect to bi-axial compressions by replacing the subscripts “L” and “T” with “V” and “H”
for the vertical and horizontal directions, respectively.

5.13 Hull Girder Ultimate Strength

In addition to the strength requirements specified in 5C-3-4/3.1, the ultimate strength of the hull-girder is
to be assessed for the combined load cases given in 5C-3-3/9.3 and the specifications given in 5C-3-5/5.13.1
and 5C-3-5/5.13.2 below.
5.13.1 Maximum Longitudinal Bending Stresses
The maximum longitudinal bending stresses in the deck and bottom plating are not to be greater
than that given in 5C-3-5/5.13.1(a) below.
5.13.1(a) fL ≤ Sm fy
where
fL = total direct stress in the longitudinal direction, N/cm2 (kgf/cm2, lbf/in2)
= fb1 + fb2

fb1 = effective longitudinal bending stress, N/cm2 (kgf/cm2, lbf/in2)

= Mt/SMe
Mt = Ms + kukcMw , ku = 1.15, kc = 1.0, N-cm (kgf-cm, lbf-in)
For vessels having significant bowflare, ku is to be increased based on 5C-3-3/11.3.3.
SMe = effective section modulus, as obtained from 5C-3-5/5.13.1(b) below, cm3 (in3)
Sm = the strength reduction factor, as defined in 5C-3-4/7.3.1

fy = minimum specified yield point of the material, N/cm2 (kgf/cm2, lbf/in2)

fb2 = secondary bending stress of large stiffened panel between longitudinal
bulkheads and transverse bulkheads, N/cm2 (kgf/cm2, lbf/in2)
5.13.1(b) Calculation of SMe (2010). For assessing the hull girder ultimate strength, the effective
section modulus is to be calculated, accounting for the buckling of the plate panels and shear lag
effects, as applicable.
i) Effective Width. The effective widths of the side, bottom shell, inner bottom plating and
longitudinal bulkhead plating are to be used instead of the full width between longitudinals.
The effective width, bwL, is given in 5C-3-5/5.3.2(a) above.

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Section 5 Total Strength Assessment 5C-3-5

ii) Shear Lag. For vessels with alternate hold loading patterns, the effective breadths (Be) of
the deck, and inner and outer bottom plating are to be determined based on the cL/bi ratio
as defined below.
cL/b = 12 10 9 8 7 6 5 4
2Be /B = 0.98 0.96 0.95 0.93 0.91 0.88 0.84 0.78
where
cL is the length between two points of zero bending moment, away from the midship, may be
taken as 60% of the vessel length.
bi is the width of the upper wing tank (bd) or the half width of the double bottom (bb), as shown in
5C-3-5/Figure 1.
For cL/bi > 12, no shear lag effects need to be considered.
The effective sectional areas of deck, inner bottom and bottom longitudinals are to be reduced by
the same ratio, 2Be /B, for calculating SMe.
Alternatively, the hull girder ultimate strength can be determined in accordance with Appendix
5C-3-A7 “Guide for Hull Girder Ultimate Strength Assessment of Bulk Carriers”.
5.13.2 Buckling and Ultimate Strength of Large Stiffened Panels
Under the combined effects of the normal stresses, fL and fT, the buckling and ultimate strength of
the stiffened panel is to satisfy the requirements specified in 5C-3-5/5.7.
5.13.3 Hull Girder Shearing Strength
The hull girder shearing stress in the side shell and longitudinal bulkhead is not to be greater than
that given below.
fs ≤ Sm fuLT
where
fs = hull girder shearing stress, N/cm2 (kgf/cm2, lbf/in2), and may be calculated
for Ft from the equations in 5C-3-4/5.3, 5C-3-4/5.5 and 5C-3-4/5.7 using net
thickness of side shell and longitudinal bulkhead
Ft = Fs + kckuFw , ku = 1.15, kc = 1.0, N-cm (kgf-cm, lbf-in).
For vessels having flare parameter Ar exceeding 21 m (68.9 ft), ku is to be increased as required by
5C-3-3/11.3.3.
Sm = strength reduction factor, as defined in 5C-3-4/7.3.1
fuLT = ultimate shearing strength of panel, as defined in 5C-3-5/5.3.3
Ar is as defined in 5C-3-3/11.3.

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Section 5 Total Strength Assessment 5C-3-5

FIGURE 1

bd

bb

L
C

A.P. cL F.P.

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 5 Total Strength Assessment 5C-3-5

7 Fatigue Life (1996)

7.1 General
The fatigue strength of welded joints and details in highly stressed areas is to be analyzed, especially where
higher strength steel is used. Special attention is to be given to structural notches, cut-outs and bracket toes
and also to abrupt changes of structural sections. A simplified assessment of the fatigue strength of
structural details may be accepted when carried out in accordance with Appendix 5C-3-A1.
The following subparagraphs are intended to emphasize the main points and to outline procedures where
refined spectral analysis techniques are used to establish fatigue strength.
7.1.1 Workmanship
Most fatigue data available were experimentally developed under controlled laboratory conditions.
Therefore, consideration is to be given to the workmanship expected during construction.
7.1.2 Fatigue Data
In the selection of S-N curves and the associated stress concentration factors, attention is to be
paid to the background of all design data and its validity for the details being considered. In this
regard, recognized design data, such as those by AWS (American Welding Society), API (American
Petroleum Institute), and DEn (Department of Energy), should be considered. Sample fatigue data
and their applications are shown in Appendix 5C-3-A1 “Guide for Fatigue Strength Assessment of
Bulk Carriers.”
If other fatigue data are to be used, the background and supporting data are to be submitted for
review.
In this regard, clarification is required whether or not the stress concentration due to the weld
profile, certain structural configurations and also the heat effects are accounted for in the proposed
S-N curve. Consideration is also to be given to the additional stress concentrations.
7.1.3 Total Stress Range
For determining total stress ranges, the fluctuating stress components resulting from the load
combinations specified in 5C-3-A1/7.5 are to be considered.
7.1.4 Design Consideration
In design, consideration is to be given to the minimization of structural notches and stress
concentrations. Areas subject to highly concentrated forces are to be properly configured and
stiffened to dissipate the concentrated loads. See also 5C-3-4/1.5.

7.3 Procedures
The analysis of fatigue strength for a welded structural joint/detail may be performed in accordance with
the following procedures.
7.3.1 Step 1 – Classification of Various Critical Locations
The class designations and associated load patterns are given in 5C-3-A1/Table 1.
7.3.2 Step 2 – Permissible Stress Range Approach
Where deemed appropriate, the total applied stress range of the structural details classified in Step
1 may be checked against the permissible stress ranges, as shown in Appendix 5C-3-A1.
7.3.3 Step 3 – Refined Analysis
Refined analyses are to be performed, as outlined in 5C-3-5/7.3.3(a) or 5C-3-5/7.3.3(b) below, for
the structural details for which the total applied stress ranges obtained from Step 2 are greater than
the permissible stress ranges, or for which the fatigue characteristics are not covered by the
classified details and the associated S-N curves.
The fatigue life of the structure is generally not to be less than 20 years unless otherwise specified.

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 5 Total Strength Assessment 5C-3-5

7.3.3(a) Spectral Analysis. Alternatively, a spectral analysis may be performed, as outlined in

5C-3-5/7.5 below, to directly calculate fatigue lives for the structural details in question.
7.3.3(b) Refined Fatigue Data. For structural details which are not covered by the detail
classifications, proposed S-N curves and the associated SCFs, when applicable, may be submitted
for consideration. In this regard, sufficient supporting data and background are also to be submitted
for review. The refined SCFs may be determined by finite element analyses.

7.5 Spectral Analysis

Where the option in 5C-3-5/7.3.3(a) is exercised, a spectral analysis is to be performed in accordance with
the following guidelines.
7.5.1 Representative Loading Patterns
Several representative loading patterns are to be considered to cover the worst scenarios anticipated
for the design service life of the vessel with respect to the hull girder local loads.
7.5.2 Environmental Representation
Instead of the design wave loads specified in Section 5C-3-3, a wave scatter diagram (such as
Walden’s Data) is to be employed to simulate a representative distribution of all of the wave
conditions expected for the design service life of the vessel. In general, the wave data is to cover a
time period of not less than 20 years. The probability of occurrence for each combination of
significant wave height and mean period of the representative wave scatter diagram is to be
weighted based on the transit time of the vessel at each wave environment within the anticipated
shipping routes. The representative environment (the wave scatter diagram) is not to be taken less
severe than the North Atlantic Ocean in terms of the fatigue damage.
7.5.3 Calculation of Wave Load RAOs
The wave load RAOs with respect to the wave induced bending moments, shear forces, motions,
accelerations and hydrodynamic pressures can then be predicted by ship motion calculation for a
selected representative loading condition.
7.5.4 Generation of Stress Spectrum
The stress spectrum for each critical structural detail (spot) may be generated by performing a
structural analysis, accounting for all of the wave loads separately for each individual wave group.
For this purpose, the 3D structural model and 2D models specified in 5C-3-5/9 may be used for
determining structural responses. The additional secondary and tertiary stresses are also to be
considered.
7.5.5 Cumulative Fatigue Damage and Fatigue Life
Based on the stress spectrum and the wave scatter diagram established above, the cumulative
fatigue damage and the corresponding fatigue life can be estimated by the Palmgren-Miner linear
damage rule.

9 Calculation of Structural Responses (1996)

9.1 Methods of Approach and Analysis Procedures (1996)

Maximum stresses in the structure are to be determined by performing structural analyses as outlined
below. Guidelines on structural idealization, load application and structural analysis are given in ABS
Guidance for Finite Element Analysis of Bulk Carrier Structures.

9.3 3D Finite Element Models (1996)

A simplified three-dimensional (3D) finite element model, usually representing three cargo holds within
0.4L amidships, is required to determine the load distribution in the structure.
The same 3D finite element model may be used for hull structures beyond 0.4L amidships, with modifications
to the structural properties and the applied loads, provided that the structural configurations are considered
as representative of the location under consideration.

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 5 Total Strength Assessment 5C-3-5

A separate 3D finite element model is recommended to represent the forebody structures for the analysis
when bottom slamming and bowflare slamming are to be considered, as specified in 5C-3-3/11.1 and
5C-3-3/11.3.

9.5 2D Finite Element Models (1996)

Two-dimensional fine mesh finite element models are required to determine the stress distribution in major
supporting structures, particularly at intersections of two or more structural members.

9.7 Local Structural Models (1996)

A 3D fine mesh finite element model is to be used to examine stress concentrations such as at intersections
of the transverse bulkheads with sloping longitudinal bulkheads.

9.9 Load Cases (1996)

When performing structural analysis, the ten combined load cases specified in 5C-3-3/9.1 are to be
considered. 5C-3-5/Table 1 indicates the load cases to be investigated in assessing the adequacy of
structures in each designated hold. In general, the structural responses for the still water conditions are to
be calculated separately to establish reference points for assessing the wave-induced responses. Additional
load cases may be required for special loading patterns and unusual design functions, such as impact loads
as specified in 5C-3-3/11. Additional load cases may also be required for hull structures beyond the region
of 0.4L amidships.

TABLE 1
Combined Load Cases to be Investigated for Each Structural Member (4)
Holds Designed for Alternate Hold Loading (1)
Structural Members/Components Loaded Holds Empty Holds Holds Designed for Ballast
Loading (1,3)
Bottom, Inner Bottom, Side, Deck, LC 1, 3, 5, 7 & 10 LC 2, 4, 6, 7, 8 & 10 LC 9 & 10
Wing Tank Structures (Plate,
Stiffeners, Frames (2), Floors,
Webs (2), Stringers (2), and Girders

Transverse Bulkhead (including LC 1, 2, 3, 4, 5, 6, 7 & 8 LC 1, 2, 3, 4, 5, 6, 7 & 8 LC 9 & 10

stools) in Holds and Tanks
Notes:
1 In general, the strength assessment is to be focused on the results obtained from structures in the mid cargo hold of
a three hold length model.
2 Notwithstanding the above, hold frames, web frames and stringers of side structures in loaded holds under
alternate loading condition are also to be assessed for load case 6, using the end holds of a three hold length model.
Similarly, transverse webs in lower and upper wing tanks in all holds are also to be assessed for load case 9, using
the end holds.
3 A ballast hold is also to be assessed as a hold designed for alternate hold loading, either loaded or empty depending
upon its designation.
4 A vessel designed for homogeneous loading only may be subject to special consideration.

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PART Section 6: Hull Structure Beyond 0.4L Amidships

5C
CHAPTER 3 Vessels Intended to Carry Ore or Bulk Cargoes
(150 meters (492 feet) or more in Length)

SECTION 6 Hull Structure Beyond 0.4L Amidships

1 General Requirements

1.1 General
The structural configurations, stiffening systems and design scantlings of the hull structures located beyond
0.4L amidships, including the forebody, aft end and machinery spaces, are to be in compliance with this
Chapter and other relevant sections of the Rules.
Forebody Structures – In addition to the requirements specified in other relevant sections of the Rules, the
scantlings of structures forward of 0.4L amidships are also to satisfy the requirements in 5C-3-6/3, 5C-3-6/5,
5C-3-6/7, 5C-3-6/9 and 5C-3-6/11 below.
The nominal design corrosion values in the forepeak tank may be taken as 1.5 mm in determining design
scantlings.

1.3 Structures within Cargo Spaces

The scantlings of longitudinal structural members and elements in way of cargo spaces beyond 0.4L
amidships may be gradually reduced toward 0.125L from the ends, provided the hull girder section modulus
is in compliance with 5C-3-4/3.1.1 and the strength of the structure satisfies the requirements specified in
5C-3-6/1.1 and the material yielding, buckling and ultimate strength criteria specified in 5C-3-5/3 and
5C-3-5/5.
In addition, consideration is to be given to the effects of bottom and bowflare slamming as specified in
5C-3-3/11.1 and 5C-3-3/11.3 with respect to the strength of both the hull girder and local structures as
outlined in 5C-3-6/13.1.
The scantlings of main supporting members (transverse webs in lower and upper wing tanks) in way of
cargo spaces beyond 0.4L amidships are to be checked for compliance with the specifications given in
5C-3-4/13. In this case, the nominal pressure is to be calculated with the hold or tank at the location under
consideration.

3 Bottom Shell Plating and Stiffeners in Forebody

3.1 Bottom Shell Plating (2002)

The net thickness of the bottom shell plating forward of 0.3L from the FP is not to be less than t1 and t2,
obtained from the following equations:
t1 = 0.73s(k1p/f1)1/2 in mm (in.)
t2 = 0.73s(k2p/f2)1/2 in mm (in.)
where
s = spacing of longitudinal, in mm (in.)
k1 = 0.342

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 6 Hull Structure Beyond 0.4L Amidships 5C-3-6

k2 = 0.50
p = nominal pressure | pi − pe |, in N/cm2 (kgf/cm2, lbf/in2), as specified in 5C-3-3/Table 3,
with the following modifications.
i) Ati is to be calculated at the forward end of the tank. Between 0.3L and 0.25L
aft of the FP, the internal pressure need not be greater than that obtained
amidships.
ii) Ae is to be calculated at the center of the panel in accordance with
5C-3-3/5.5.3, using L.C.1 and wave trough located amidships.
iii) Be is to be calculated at the center of the panel in accordance with
5C-3-3/5.5. (ps + ku pd, full draft, heading angle = 0, ku = 1.1)
iv) (1999) Where upper and lower wing tanks are connected by trunks or double
sides, the internal pressure, pi, in the lower wing tank may be calculated by
the following equation:
v) pi = pia − puh
vi) pia is internal pressure in the lower wing tank, in N/cm2 (kgf/cm2, lbf/in2), as
defined in 5C-3-3/Table 3 for bottom plating.
vii) puh is as defined in 5C-3-4/7.3.1.
f1/f2 = permissible bending stress in the longitudinal/transverse direction, in N/cm2 (kgf/cm2,
lbf/in2)
f1 = 0.45 Sm fy , forward of 0.2L from the FP
f2 = 0.8 Sm fy
Sm and fy are as defined in 5C-3-4/7.3.1. The permissible stress, f1, between 0.3L and 0.2L from the FP is to
be obtained by linear interpolation between midship region (5C-3-4/7.3.1) and the permissible stress at
0.2L from the FP, as specified above.
Bottom shell plating may be transversely framed in limited areas such as pipe tunnels, provided the net
thickness of the bottom shell plating is not less than t3, obtained from the following equation:
t3 = 0.73sk(k2 p/f3)1/2 mm (in.)
where
s = spacing of bottom transverse frame, in mm (in.)
k2 = 0.5

k = (3.075(α)1/2 − 2.077)/(α + 0.273), (1 ≤ α ≤ 2)

= 1.0 (α > 2)
α = aspect ratio of the panel (longer edge/shorter edge)
f3 = 0.45Smfy at 0.2L from the FP
= 0.6Smfy forward of 0.1L from the FP
The permissible stress, f3, between 0.2L and 0.1L from the FP is to be obtained by linear interpolation. The
permissible stress, f3, between 0.3L and 0.2L from the FP is to be obtained by linear interpolation between
midship region (5C-3-4/7.3.1) and the permissible stress at 0.2L from the FP, as specified above. All other
parameters are as defined above.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 445
Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 6 Hull Structure Beyond 0.4L Amidships 5C-3-6

3.3 Bottom Longitudinals/Stiffeners

The section modulus of the longitudinal/stiffener, including the associated effective plating on the bottom
plating forward of 0.3L from the FP, is not to be less than that obtained from the following equation:
SM = M/fb cm3 (in3)

M = 1000psl2/k N-cm (kgf-cm, lbf-in)

where
k = 12 (12, 83.33)
p = nominal pressure | pi − pe |, in N/cm2 (kgf/cm2, lbf/in2), as specified in 5C-3-3/Table 3
with the following modifications.
i) Ati is to be calculated at the forward end of the tank. Between 0.3L and 0.25L
aft of the FP, the internal pressure need not be greater than that obtained
amidships.
ii) Ae is to be calculated at the middle of the unsupported span in accordance
with 5C-3-3/5.5.3 using L.C.1 and wave trough located amidships.
iii) Be is to be calculated at the middle of the unsupported span in accordance
with 5C-3-3/5.5 (ps + kuPd, full draft, heading angle = 0, ku = 1.1)
iv) (1999) Where upper and lower wing tanks are connected by trunks or double
sides, the internal pressure, pi, in the lower wing tank may be calculated as
defined in 5C-3-6/3.1iv).
s = spacing of longitudinal or transverse stiffeners, in mm (in.)
l = the unsupported span of the longitudinal or stiffener, in m (ft)
fb = 0.65 Sm fy, in N/cm2 (kgf/cm2, lbf/in2)
The effective breadth of plating, be, is as defined in 5C-3-4/7.5. The permissible stress, fb, between 0.3L
and 0.2L from the FP is to be obtained by linear interpolation between midship region (5C-3-4/7.5) and the
permissible stress at 0.2L from the FP, as specified above.

3.5 Bottom Girders and Floors

The net thickness of bottom girders and floors may be determined by the equations given in 5C-3-4/7.7,
5C-3-4/7.9, and 5C-3-4/7.11, with the following modifications.
bs = bsa − (bsa − bsf ) x/ls
where
x = longitudinal distance from the aft end of double bottom length (ls) to the location
under consideration, in m (ft)
bsa = breadth at the aft end of the double bottom structure under consideration, in m (ft), as
shown in 5C-3-6/Figure 1
bsf = breadth at the forward end of the double bottom structure, in m (ft), as shown in
5C-3-6/Figure 1
β1 = 1 − (1.2z1/bsa) ≥ 0.6 for loaded holds under alternate loading conditions
= 1.25 − (2z1/bsa) ≥ 0.6 for all holds or tanks under all other loading conditions and for
slamming loads
β3 = 1 − 0.4z2/bsa for loaded holds under alternate loading conditions
= 1 for all holds or tanks under all other loading conditions and for slamming loads

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 6 Hull Structure Beyond 0.4L Amidships 5C-3-6

γ1 = (Ccg − x)/(ls − Ccg − sf /2) ≤ 1.0 for x ≤ Ccg for centerline girder

= (x − Ccg)/(ls − Ccg − sf /2) ≤ 1.0 for x > Ccg for centerline girder

= (Csg − x)/(lsg − Csg − sf /2) ≤ 1.0 for x ≤ Csg for side girder

= (x − Csg)/(lsg − Csg − sf /2) ≤ 1.0 for x > Csg for side girder

γ2 = 1 − (Cf − x)(1.245λ + 0.044)/2Cf ≥ 0.4 for x ≤ Cf for floor

= 1 − (x − Cf)(1.245λ + 0.044)/2Cf ≥ 0.4 for x > Cf for floor

Ccg = [ls(2bsf + bsa)]/[3(bsa + bsf)]

Csg = Ccg for z1 ≤ bsf /2

= [ls (bsa − 2z1)(4z1 + bsa)]/[3(bsa − bsf) (bsa + 2z1)] for z1 > bsf /2

Cf = (1.08 − 0.58(bsf /bsa)1/2)ls

lsg = ls for z1 ≤ bsf /2

= [ls (bsa − 2z1)/(bsa − bsf)] for z1 > bsf /2

For calculation of shear force in the side girders, lsg is to be used in lieu of ls.
P = nominal pressure |pi − pe|, in kN/m2 (tf/m2, Ltf/ ft2), as specified in 5C-3-3/Table 3,
with modification that Abi, Ae and Be are to be calculated in accordance with
5C-3-3/5.5 and 5C-3-3/5.7 at the center of the double bottom under consideration. Ae
is to be calculated at the center of the double bottom with wave trough located
amidships. Be is to be calculated with wave crest at the center of the double bottom
under consideration. The pressure is not to be taken less than required by 5C-3-4/7.7,
5C-3-4/7.9 and 5C-3-4/7.11 for the double bottom amidships.
The net thickness of floors and girders (including centerline girder) are also not to be less than the following:
t = (0.026L + 4.5)R mm (in.)
where
L is as defined in 3-1-1/3.
R is as defined in 5C-3-4/7.7.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 447
Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 6 Hull Structure Beyond 0.4L Amidships 5C-3-6

FIGURE 1
Double Bottom Structure in Forebody Region

bsf

P
ls

CL

bsa

448 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 6 Hull Structure Beyond 0.4L Amidships 5C-3-6

5 Side Shell Plating and Stiffeners in Forebody

5.1 General
The thickness as determined below is to be extended from the bilge to the freeboard deck, provided there is
no significant bowflare (see 5C-3-3/11.3).
Otherwise, the thickness of side shell plating above the LWL is to be determined based on 5C-3-6/13.1 of
this section

5.3 Plating Forward of Forepeak Bulkhead

The net thickness of the side shell plating forward of the forepeak bulkhead is to be not less than t1, t2 and
t3, specified below.
t1 = 0.73s(k1 p/f1)1/2 in mm (in.)
t2 = 0.73s(k2 p/f2)1/2 in mm (in.)
t3 = 0.73sk(k3 pb /f3)1/2 in mm (in.) for side shell and bow plating above the LWL in the
region from the forward end to the forepeak bulkhead
where
s = spacing of stiffeners, in mm (in.)
k1 = 0.342 for longitudinally and 0.50 for transversely stiffened plating
k2 = 0.50 for longitudinally and 0.342 for transversely stiffened plating
k3 = 0.50
k = (3.075(α)1/2 − 2.077)/(α + 0.272), (1 ≤ α ≤ 2)
= 1.0 (α > 2)
α = aspect ratio of the panel (longer edge/shorter edge)
f1 = 0.45 Sm fy, in N/cm2 (kgf/cm2, lbf/in2), in the longitudinal direction for longitudinally
stiffened plating (1998)
f1 = 0.60 Sm fy, in N/cm2 (kgf/cm2, lbf/in2), in the longitudinal direction for transversely
stiffened plating (1998)
f2 = 0.80 Sm fy, in N/cm2 (kgf/cm2, lbf/in2), in the transverse (vertical) direction

f3 = 0.85 Sm fy, in N/cm2 (kgf/cm2, lbf/in2)

p = nominal pressure |pi − pe|, in N/cm2 (kgf/cm2, lbf/in2), as specified in 5C-3-3/Table 3
at the upper turn of bilge level amidships, with the following modifications:
i) Ati is to be calculated at the forward or aft end of the tank, whichever is
greater
ii) Ae is to be calculated at the center of the panel in accordance with
5C-3-3/5.5.3, using L.C.7 with kfo = 1.0 and xo located amidships
iii) Be is to be calculated at 0.05L from the FP in accordance with 5C-3-3/5.5
(ps + ku pd , full draft, heading angle = 0, ku = 1.1)
pb = design bow pressure = ku pbij
ku = 1.1
pbij = nominal bow pressure, as specified in 5C-3-3/5.5.4 at the center of the supported
panel under consideration, in N/cm2 (kgf/cm2, lbf/in2)
Sm and fy are as defined in 5C-3-4/7.3.1.

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 6 Hull Structure Beyond 0.4L Amidships 5C-3-6

5.5 Plating between Forepeak Bulkhead and 0.125L from the FP

Aft of the forepeak bulkhead and forward of 0.125L from the FP, the side shell plating is to be not less than
as given in 5C-3-6/5.3 with Be calculated at 0.125L. Side shell plating in upper and lower wing tanks, see
5C-3-6/5.9.

5.7 Plating between 0.3L and 0.125L from the FP (1998)

The net thickness of the side shell plating between 0.3L and 0.125L from the FP is to be determined from
the equations in 5C-3-6/5.3 and 5C-3-6/5.5 above, with Be calculated at the longitudinal location under
consideration. Between 0.3L and 0.25L from the FP, the internal pressure need not be greater than that
obtained amidships. The permissible stress f1 between 0.3L and 0.2L from the FP is to be obtained by linear
interpolation between midship region (5C-3-4/9.1) and the permissible stress f1, as specified in 5C-3-6/5.3.
Side shell plating in upper and lower wing tanks, see 5C-3-6/5.9.

5.9 Plating in Upper and Lower Wing Tanks

The side shell is to be longitudinally framed in the lower and upper wing tanks, except the upper part of the
lower wing tank and the lower part of the upper wing tank where the limited access makes this impractical.
These portions of the side shell may be transversely framed with efficient brackets arranged in line with
the side frames, provided the net thickness of the side shell plating in this area is not less than that of the
adjacent longitudinally framed shell and is also not less than t4, obtained from the following equation:

t4 = 0.73sk(k2 p/f)1/2 mm (in.)

where
s = spacing of side transverse brackets, in mm (in.)
k = (3.075(α)1/2 − 2.077)/(α + 0.272) (1 ≤ α ≤ 2)
= 1.0 (α > 2)
α = aspect ratio of the panel (longer edge/shorter edge)
k2 = 0.5
p = nominal pressure |pi − pe| at the lower end of the panel, as specified in 5C-3-3/Table 3
with the following modifications:
i) Ati is to be calculated at the forward or aft end of the tank, whichever is
greater. Between 0.3L and 0.25L aft of the FP, the internal pressure need not
be greater than that obtained amidships
ii) Ae is to be calculated in accordance with 5C-3-3/5.5.3 using L.C.7 with kfo =
1.0 and xo located amidships
iii) Be is to be calculated in accordance with 5C-3-3/5.5 (ps + ku pd, full draft,
heading angle = 0, ku = 1.1)
iv) (1999) In the upper wing tank and the lower wing tank which is connected to
the upper wing tank by trunks or double sides, the internal pressure, pi, in the
wing tanks may be calculated by the following equation:
pi = pia − puo
pia is internal pressure in the wing tanks, in N/cm2 (kgf/cm2, lbf/in2), as
defined in 5C-3-3/Table 3 for side shell plating.
puo is as defined in 5C-3-4/9.1.

f = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)

= 0.60 Sm fy within 0.2L from the FP

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Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 6 Hull Structure Beyond 0.4L Amidships 5C-3-6

The permissible stress, f, between 0.3L and 0.2L from the FP is to be obtained by linear interpolation
between midship region (5C-3-4/9.1) and the permissible stress at 0.2L from the FP, as specified above.
The net thickness of the side shell plating, where transversely framed between upper and lower wing tanks,
is not to be less than t4, as specified above, with the nominal pressure calculated at the top of lower wing
tank. The thickness is also not to be less than that of the adjacent shell.

5.11 Side Frames and Longitudinals Forward of 0.3L from the FP

The net section modulus of side longitudinals and frames in association with the effective plating to which
they are attached, is to be not less than that obtained from the following equation:
SM = M/fbi in cm3 (in3)

M = 1000psl2/k in N-cm (kgf-cm, lbf-in)

where
k = 12 (12, 83.33)
p = nominal pressure |pi − pe|, in N/cm2 (kgf/cm2, lbf/in2), as specified in 5C-3-3/Table 3
with the following modifications:
i) Ati is to be calculated at the forward or aft end of the tank, whichever is
greater. Between 0.3L and 0.25L aft of the FP the internal pressure need not
be greater than that obtained amidships.
ii) Ae is to be calculated at the center of the panel, in accordance with
5C-3-3/5.5.3 using L.C.7 with kfo = 1.0 and xo located amidships.
iii) Be is to be calculated at the center of the panel, in accordance with
5C-3-3/5.5 (ps + ku pd, full draft, heading angle = 0, ku = 1.1), with the
distribution of pd, as shown in 5C-3-6/Figure 2, at the side longitudinal and
frame under consideration.
iv) (1999) In the upper wing tank and the lower wing tank which is connected to
the upper wing tank by trunks or double sides, the internal pressure, pi, in the
wing tanks may be calculated as defined in 5C-3-6/5.9iv).
Longitudinal distribution of pd may be taken as constant from the FP to the forepeak bulkhead, as per
5C-3-6/5.3, and from 0.125L to the forepeak bulkhead, as per 5C-3-6/5.5. pd is to be calculated in
accordance with 5C-3-3/5.5 between 0.3L and 0.125L from the FP, as per 5C-3-6/5.7.
fbi = 0.80 Sm fy, in N/cm2 (kgf/cm2, lbf/in2) for longitudinals between 0.125L and 0.2L
from the FP
= 0.85 Sm fy, in N/cm2 (kgf/cm2, lbf/in2) for longitudinals forward 0.125L from the FP
= 0.85 Sm fy, in N/cm2 (kgf/cm2, lbf/in2) for vertical frames (other than hold frames)
Between 0.3L and 0.2L from the FP, the permissible stress is to be obtained by linear interpolation between
midship region and 0.80Sm fy
Sm and fy are as defined in 5C-3-4/7.3.1.

s and l are as defined in 5C-3-4/7.5.

For side longitudinals/stiffeners in the region forward of 0.0125L from the FP and above the LWL, the
section modulus is not to be less than obtained from the above equation, based on p = pb, fb = 0.95Sm fy and
k = 16 (16, 111.1), where pb is as defined in 5C-3-6/5.3 above.

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 6 Hull Structure Beyond 0.4L Amidships 5C-3-6

5.13 Hold Frames

The net section modulus of the hold frames forward 0.3L measured from the FP, in association with
effective shell plating to which they are attached, is not to be less than obtained from the following equation:
SMF = M/fb in cm3 (in3)

M = 1000c1psl2/k in N-cm (kgf-cm, lbf-in)

where
k = 12 (12, 83.33)
l = unsupported span of hold frames, in m (ft), (see 5C-3-4/Figure 6) measured along the
chord of the member
p = nominal external pressure, in N/cm2 (kgf/cm2, lbf/ in2), at the middle of the
unsupported span of each hold frame, calculated in accordance with 5C-3-3/5.5.
= ps + ku pd, (Full draft, wave heading angle = 0, ku = 1.1)

fb = 0.80 Sm fy, in N/cm2 (kgf/cm2, lbf/in2)

c1 and s are as defined in 5C-3-4/11.3.
Sm and fy are as defined in 5C-3-4/7.3.1.
The effective breadth of plating, be, is as defined in 5C-3-4/7.5.
Where a cargo hold is intended to be used for the carriage of water ballast or liquid cargoes, the net section
modulus of the hold frame is also not to be less than obtained from the above equation with p as nominal
internal pressure, in N/cm2 (kgf/cm2, lbf/in2), at the middle of unsupported span of hold frames calculated
in accordance with 5C-3-3/5.7 for the forward end of the particular hold [5C-3-3/Table 3 hold frame
(ballast or liquid cargo holds)].
The net section modulus of the lower and upper brackets at the top of the lower wing tank and the bottom
of the upper wing tank is not to be less than obtained from 5C-3-4/11.7.1 with h3 as the chord distance, in
m (ft), measured between the top of the lower wing tank and the bottom of the upper wing tank.
The net thickness of the upper and lower brackets and the web part of the frames is not to be less than as
specified in 5C-3-4/11.7.3, respectively.

5.15 Hold Frames in the Foremost Cargo Hold (1 July 1998)

In addition to the requirements of 5C-3-6/5.13, hold frames in the foremost cargo hold are to meet the
following requirements.
i) The gross thickness of the web portion of the frames is to be increased by a factor of 1.15 over
that required by 5C-3-4/11.7.3, except that tn need not exceed 13.5 mm (0.53 in.)
ii) The gross thickness of lower brackets is to be at least the gross thickness of the web of the frames
being supported or the gross thickness required by 5C-3-6/5.15i) above, increased by 2 mm (0.08 in.),
whichever is greater.
iii) The gross thickness of upper brackets is to be at least the gross thickness of the web of the frames
being supported or the gross thickness required by 5C-3-6/5.15i) above, whichever is greater.
iv) When hold frames are asymmetric sections, tripping brackets are to be fitted at approximately
mid-span and at every two frames, as shown in 5C-3-6/Figure 3.

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 6 Hull Structure Beyond 0.4L Amidships 5C-3-6

FIGURE 2
Transverse Distribution of pd

Pd0 = Pg (see 5C-3-3/5.5.4)

Freeboard Deck

Pd1 LWL

Bilge Radius
Amidships

Pd2

L
C

FIGURE 3
Arrangement of Tripping Brackets for Hold Frames
with Asymmetric Sections (1 July 1998)

HOLD NO. 1

ASYMMETRIC
BHD

SIDE FRAME
FP

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 6 Hull Structure Beyond 0.4L Amidships 5C-3-6

7 Side Transverses and Stringers in Forebody

7.1 Section Modulus

The net section modulus of side transverses and stringers in association with the effective side shell plating
is not to be less than that obtained from the following equation:
SM = M/fb in cm3 (in3)

7.1.1 Longitudinally Framed Side Shell

For side stringer
M = 1000c1c2 pslt ls /k in N-cm (kgf-cm, lbf-in)
For side transverse, M is not to be less than M1 or M2, whichever is greater.

M1 = 1000c3 ps l 2t (1.0 − c4φ)/k in N-cm (kgf-cm, lbf-in)

M2 = 850p1s l 2t1 /k in N-cm (kgf-cm, lbf-in)

where
k = 0.12 (0.12, 0.446)
c1 = 0125 + 0.875φ, but not less than 0.3
Coefficients c2, c3 and c4 are given in the tables below.

Coefficient c2
Number of Side Stringers No Stringer One Stringer More than one
Between Platforms (flats) Stringer
Top Stringer 0.70
Stringers Between Top and 0.0 0.90 0.75
Lowest Stringers
Lowest Stringer 0.80

Coefficient c3
Number of Side Stringers No Stringer One Stringer More than one
Between Platforms (flats) Stringer
Transverse above Top 0.55 0.55
Stringer
Transverse Between Top 0.85 — 0.64
and Lowest Stringers
Transverse Below Lowest 0.68 0.68
Stringer

Coefficient c4
Number of Side Stringers No Stringer One Stringer More than one
Between Platforms (flats) Stringer

Transverses 0.0 0.75 0.80

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 6 Hull Structure Beyond 0.4L Amidships 5C-3-6

p = nominal pressure, |pi − pe|, in kN/m2 (tf/m2, Ltf/ft2), over the side transverses
using the same load cases as specified in 5C-3-3/Table 3 for side transverses
in lower wing tank. Ati, Ae and Be may be taken at the center of the side shell
panel under consideration with the following modifications:
i) Ae is to be calculated in accordance with 5C-3-3/5.5.3, using L.C.7
with kfo = 1.0 and xo located amidships
ii) Be is to be calculated in accordance with 5C-3-3/5.5 (ps + ku pd , full
draft, heading angle = 0, ku = 1) with the distribution of pd as shown
in 5C-3-6/Figure 2.
p1 = nominal pressure, |pi − pe|, in kN/m2 (tf/m2, Ltf/ft2), using the same load
cases as specified in 5C-3-3/Table 3 for side transverses in lower wing tank,
with Ati, Ae and Be calculated at the midspan ls1 (between side stringers or
between side stringer and platform, flat as shown in 5C-3-6/Figure 4 ) of the
side transverse under consideration, with the following modifications:
i) Ae is to be calculated in accordance with 5C-3-3/5.5.3, using L.C.7
with kfo = 1.0 and xo located amidships
ii) Be is to be calculated in accordance with 5C-3-3/5.5 (ps + ku pd , full
draft, heading angle = 0, ku = 1) with the distribution of pd as shown
in 5C-3-6/Figure 2.
For side transverses
s = sum of half distances, in m (ft), between side transverse under consideration
and adjacent side transverses or transverse bulkhead
For side stringers
s = 0.45ls

φ = 1/(1 + α)
α = 1.33(It /Is)(ls/lt)3
It = moment of inertia, in cm4 (in4), (with effective side plating) of side transverse.
It is to be taken as average of those at the middle of each span lt1 between
side stringers or side stringer and platform (flat), clear of the bracket
Is = moment of inertia, in cm4 (in4), (with effective side plating) of side stringer
at the middle of the span ls, clear of the bracket
lt, ls = spans, in m (ft), of the side transverse (lt) and side girder (ls) under
consideration as shown in 5C-3-6/Figure 4
lt1 = span, in m (ft), of side transverse under consideration between stringers, or
stringer and platform (flat) as shown in 5C-3-6/Figure 4b
When calculating α, if more than one side transverse or stringer is fitted and they are not identical,
average values of It and Is within side shell panel (panel between transverse bulkheads and platforms,
flats) are to be used.
fb = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.75 Sm fy
Sm and fy are as defined in 5C-3-4/7.3.1.
The bending moment for a side transverse below stringer (or below the platform if no stringer is
fitted) is not to be less than 80% of that for a side transverse above stringer (or above platform if
no stringer is fitted).

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 6 Hull Structure Beyond 0.4L Amidships 5C-3-6

7.1.2 Transversely Framed Side Shell

For side transverses:
M = 1000c1psltls /k in N-cm (kgf-cm, lbf-in)
For side stringers, M is not to be less than M1 or M2, whichever is greater:

M1 = 1000c2 ps l 2s (1.0 − c3φ1)/k in N-cm (kgf-cm, lbf-in)

M2 = 1100p1s l 2s1 /k in N-cm (kgf-cm, lbf-in)

where
k = 0.12 (0.12, 0.446)
c1 = 0.10 + 0.7φ1, but not to be taken less than 0.085
If no side transverses are fitted between transverse bulkheads
c2 = 1.1
c3 = 0
If side transverses are fitted between transverse bulkheads
c2 = 0.8
c3 = 0.8
p = nominal pressure, |pi − pe|, in kN/m2 (tf/m2, Ltf/ft2), over the side stringers
using the same load cases as specified in 5C-3-3/Table 3 for side transverses
in lower wing tank. Ati, Ae and Be may be taken at the center of the side shell
panel under consideration with the following modifications
i) Ae is to be calculated in accordance with 5C-3-3/5.5.3, using L.C.7
with kfo = 1.0 and xo located amidships
ii) Be is to be calculated in accordance with 5C-3-3/5.5 (ps + ku pd , full
draft, heading angle = 0, ku = 1) with the distribution of pd as shown
in 5C-3-6/Figure 2.
p1 = nominal pressure, |pi − pe|, in kN/m2 (tf/m2, Ltf/ft2), using the same load
cases as specified in 5C-3-3/Table 3 for side transverses in lower wing tank,
with Ati, Ae and Be calculated at the midspan ls1 (between side transverses or
between side transverse and transverse bulkhead as shown in 5C-3-6/Figure
4a) of the side stringer under consideration, with the following
modifications.
i) Ae is to be calculated in accordance with 5C-3-3/5.5.3, using L.C.7
with kfo = 1.0 and xo located amidships
ii) Be is to be calculated in accordance with 5C-3-3/5.5 (ps + ku pd , full
draft, heading angle = 0, ku = 1) with the distribution of pd as shown
in 5C-3-6/Figure 2.
For side stringers
s = sum of half distances, in m (ft), between side stringer under consideration
and adjacent side stringers or platforms (flats)
For side transverses
s = 0.45lt

φ1 = α/(1 + α)

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 6 Hull Structure Beyond 0.4L Amidships 5C-3-6

ls1 = span, in m (ft), of the side stringer under consideration between side transverses
or side transverse and transverse bulkhead, as shown in 5C-3-6/Figure 4a
fb = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.75 Sm fy
Sm and fy are as defined in 5C-3-4/7.3.1.

lt, ls and α are as defined in 5C-3-6/7.1.1.

7.3 Sectional Area of Web

The net sectional area of the web portion of the side transverse and side stringer is not to be less than
obtained from the following equation.
A = F/fs

7.3.1 Longitudinally Framed Side Shell

For side stringers:
F = 1000kc1pls N (kgf, lbf)
For side transverses, F is not to be less than F1 or F2, whichever is greater:

F1 = 850kc2pls(1.0 − c3φ − 2he /l) N (kgf, lbf)

F2 = 1700kc2p1s(0.5l1 − he) N (kgf, lbf)

where
k = 0.5 (0.5, 1.12)
Coefficients c1, c2 and c3 are given in the tables below.

Coefficient c1
Number of Side Stringers No Stringer One Stringer More than one
Between Platforms (flats) Stringer
Stringers 0.0 0.52 0.40

Coefficient c2
Number of Side Stringers No Stringer One Stringer More than one
Between Platforms (flats) Stringer
Transverses Above Top 0.9 0.9
Stringer
Transverse Between Top 1.0 — 0.95
and Lowest Stringers
Transverse Below Lowest 1.0 1.0
Stringer

Coefficient c3
Number of Side Stringers No Stringer One Stringer More than one
Between Platforms (flats) Stringer
Transverses 0.0 0.5 0.6

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 6 Hull Structure Beyond 0.4L Amidships 5C-3-6

l = span, in m (ft), of the side transverse under consideration between platforms

(flats), as shown in 5C-3-6/Figure 4b
l1 = span, in m (ft), of the side transverse under consideration between side
stringers or side stringer and platform (flat), as shown in 5C-3-6/Figure 4b
he = length, in m (ft), of the end bracket of the side transverse, as shown in
5C-3-6/Figure 4b
To obtain F1, he is equal to the length of the end bracket at the end of span l of side transverse, as
shown in 5C-3-6/Figure 4b.
To obtain F2, he is equal to the length of the end bracket at the end of span l1 of side transverse, as
shown in 5C-3-6/Figure 4b.
fs = permissible shear stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.45 Sm fy
Sm and fy are as defined in 5C-3-4/7.3.1.

p, p1, φ and s are as defined in 5C-3-6/7.1.1.

The shear force for the side transverse below the lowest stringer (or below the platform if no
stringer is fitted), is not to be less than 110% of that for the side transverse above the top stringer
(or above the platform is no stringer is fitted).
7.3.2 Transversely Framed Side Shell
For side transverses:
F = 850kc1pls in N (kgf, lbf)
For side stringers, F is not to be less than F1 or F2, whichever is greater:

F1 = 1000kpls(1.0 − 0.6φ1 − 2he /l) in N (kgf, lbf)

F2 = 2000kp1s(0.5l1 − he) in N (kgf, lbf)

where
k = 0.5 (0.5, 1.12)
c1 = 0.1 + 0.7φ1, but not to be taken less than 0.2

l = span, in m (ft), of the side stringer under consideration between transverse

bulkheads, as shown in 5C-3-6/Figure 4a
l1 = span, in m (ft), of the side stringer under consideration between side transverses
or side transverse and bulkhead, as shown in 5C-3-6/Figure 4a
he = length, in m (ft), of the end bracket of the side stringer under consideration,
as shown in 5C-3-6/Figure 4a
To obtain F1, he is equal to the length of the end bracket at the end of span l of the side stringer, as
shown in 5C-3-6/Figure 4a.
To obtain F2, he is equal to the length of the end bracket at the end of span l1 of the side stringer,
as shown in 5C-3-6/Figure 4a.
fs = permissible shear stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.45 Sm fy
Sm and fy are as defined in 5C-3-4/7.3.1.

p, p1, φ1 and s are as defined in 5C-3-6/7.1.2 above.

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 6 Hull Structure Beyond 0.4L Amidships 5C-3-6

7.5 Depth of Transverse/Stringer

The depths of side transverses and stringers, dw, are neither to be less than obtained from the following
equations, nor to be less than 2.5 times the depth of the slots, respectively.
7.5.1 Longitudinally Framed Shell
For side transverses:
If side stringer is fitted between platforms (flats):
dw = (0.08 + 0.80α)lt for α ≤ 0.05

= (0.116 + 0.084α)lt for α > 0.05

and need not be greater than 0.2lt

If no side stringer is fitted between platforms (flats), dw is not to be less than 0.2lt or 0.06D,
whichever is greater.
For side stringers:
dw = (0.42 − 0.9α)ls for α ≤ 0.2

= (0.244 − 0.0207α)ls for α > 0.2

α is not to be taken greater than 8.0 to determine the depth of the side stringer.
lt, ls and α are as defined in 5C-3-6/7.1.1.
D is as defined in 3-1-1/7.
7.5.2 Transversely Framed Side Shell
For side stringers:
If side transverse is fitted between transverse bulkheads
dw = (0.08 + 0.80α1)ls for α1 ≤ 0.05

= (0.116 + 0.084α1)ls for α1 > 0.05

and need not be greater than 0.2ls.

If no side transverse is fitted between transverse bulkheads
dw = 0.2ls
For side transverses:
dw = (0.277 − 0.385α1)lt for α1 ≤ 0.2

= (0.204 − 0.205α1)lt for α1 > 0.2

α1 is not to be taken greater than 7.5 to determine the depth of the side transverse.
where
α1 = 1/α
lt, ls and α are as defined in 5C-3-6/7.1.1 above.

7.7 Thickness
The net thickness of side transverse and stringer is not to be less than 9.5 mm (0.374 in.).

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Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 6 Hull Structure Beyond 0.4L Amidships 5C-3-6

FIGURE 4
Definition of Spans

he

he h
e SIDE
SHEL
L
he
ls1
ls

ls1

l1

TRANSV. BHD
TRANSV. BHD

a. Stringer

PLATFORM FLAT

he

l1
lt1
he

he lt l

lt1
SIDE SHELL

l1

he
PLATFORM FLAT

b. Transverse

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 6 Hull Structure Beyond 0.4L Amidships 5C-3-6

9 Deck Structures in Forebody (1999)

9.1 General
The deck plating, longitudinals, beams, girders and transverses forward of 0.25L from the FP are to meet
the requirements specified in 5C-3-4/15 with the deck pressure, p = pg, where pg is the nominal green water
loading given in 5C-3-3/5.5.4(b) or the normal internal pressure as specified in 5C-3-3/Table 3 at the
forward end of the particular tank, whichever is greater, and the permissible stresses as specified below.
The nominal internal pressure for deck plating and longitudinals in the upper wing tank may be calculated
by the following equation:
p = pi − puh

In no case is p to be taken less than 2.06 N/cm2 (0.21 kgf/cm2, 2.987 lbf/in2).
pi is nominal pressure in N/cm2 (kgf/cm2, lbf/in2), as defined in 5C-3-3/Table 3 for deck members within
the upper wing tank.
puh is as defined in 5C-3-4/7.3.1.

9.3 Deck Plating (1999)

The net thickness of deck plating is to be not less than t1 and t2, as specified in 5C-3-4/15.1, with the
following modifications:
f1 = 0.50 Sm fy, in N/cm2 (kgf/cm2, lbf/in2), for main deck within 0.1L from the FP.
f1 = 0.60 Sm fy, in N/cm2 (kgf/cm2, lbf/in2), for forecastle deck
f2 = 0.80 Sm fy, in N/cm2 (kgf/cm2, lbf/in2)
The permissible stress, f1, for main deck between 0.25L and 0.1L from the FP is to be obtained by linear
interpolation between midship region (5C-3-4/15.1) and the permissible stress at 0.1L from the FP, as
specified above.
In addition, the net thickness of main deck plating is also not to be less than t3, as specified below.
t3 = 0.30s(Sm fy /E)1/2 mm (in.) for main deck within 0.1L from the FP
The required thickness, t3, between 0.30L and 0.1L from the FP is to be obtained by linear interpolation
between midship region and the t3 above.
The net thickness, t3, may be determined based on Sm and fy of the hull girder strength material required at
the location under consideration.

9.5 Deck Longitudinals/Beams

The net section modulus is not to be less than obtained from 5C-3-4/15.3 with the following modifications.
fb = 0.70 Sm fy, in N/cm2 (kgf/cm2, lbf/in2), for main deck longitudinals within 0.1L from the FP
and forecastle deck longitudinals
fb = 0.80 Sm fy, in N/cm2 (kgf/cm2, lbf/in2), for main deck beams forward of the foremost hatch
opening (No. 1 hatch) and forecastle deck beams
The permissible bending stress, fb, for main deck longitudinals between 0.25L and 0.1L from the FP is to
be obtained by linear interpolation between midship region (5C-3-4/15.3) and the permissible stress at 0.1L
from the FP, as specified above.

9.7 Cross Deck Beams

The net section modulus of the deck beams inside the lines of hatch openings Nos. 1 and 2 is not to be less
than obtained from 5C-3-4/15.7 with the green water loading and the following modification, or directly
obtained from 5C-3-4/15.7, whichever is greater.
fb = 0.6 Sm fy, in N/cm2 (kgf/cm2, lbf/in2)

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 6 Hull Structure Beyond 0.4L Amidships 5C-3-6

9.9 Hatch End Beams

The scantlings of hatch end beams are to satisfy 5C-3-4/17.5 with the green water loading and the following
modification, or directly obtained from 5C-3-4/17.5, whichever is greater.
fb = 0.9 Sm fy, in N/cm2 (kgf/cm2, lbf/in2)

q = (pg − kd), in kN/m2 (tf/m2, Ltf/ft2)

where
d = depth of hatch coaming, in m (ft)
pg = nominal green water pressure, in kN/m2 (tf/m2, Ltf/ft2)
k = 10.05 (1.025, 0.0286)

9.11 Deck Girders Inside the Lines of Hatch Opening

The scantlings of deck girders inside the lines of hatch openings are to satisfy 5C-3-4/17.7 with the green
water loading and the following modification, or directly obtained from 5C-3-4/17.7, whichever is greater.
fb = 0.9 Sm fy, in N/cm2 (kgf/cm2, lbf/in2)

q = (pg − kd), in kN/m2 (tf/m2, Ltf/ft2)

where
d = depth of hatch coaming, in m (ft)
k = 10.05 (1.025, 0.0286)

9.13 Deck Transverse in Upper Wing Tank

The scantlings of deck transverses are to satisfy 5C-3-4/13.5 with the green water loading and the following
modification, or directly obtained from 5C-3-4/13.5, whichever is greater.
M1 = 0, for 5C-3-4/13.5.1

F = 1000kpgs(0.5l − he) N (kgf, lbf) for 5C-3-4/13.5.2

where
k = 0.9 (0.9, 2.016)
l = span, in m (ft.), of deck transverse, as shown in 5C-3-4/Figure 9
he = length, in m (ft.), of the end brackets of deck transverse, as shown in 5C-3-4/Figure 9
s is as defined in 5C-3-4/13.5.1.

11 Transition Zone

11.1 General (2002)

In the transition zone between the forepeak and the No. 1 cargo hold, due consideration is to be given to
the proper tapering of major longitudinal members within the forepeak such as flats, decks, horizontal ring
frames or side stringers aft into the cargo hold. Where such structure is in line with longitudinal members
aft of the forward cargo hold bulkhead, such as in the upper and lower wing tanks, this may be effected by
the fitting of large tapering brackets inside the wing tanks. These brackets are to have a taper of 4:1 based
on the size of the wing tank longitudinal. When forepeak structure does not align with longitudinal
structure in the cargo hold area and terminates at the forward cargo hold bulkhead, in way of the hold
frames, either of the following arrangements is to be adopted.

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 6 Hull Structure Beyond 0.4L Amidships 5C-3-6

11.1.1
For a stringer, a bracket of length 21/2 times the depth of the stringer or 3 frame spaces, whichever
is greater, is to be fitted at the end of the stringer. The bracket is to be gradually tapered, suitably
stiffened and have collars fitted at the slots for the vertical frames. (See 5C-3-6/Figure 5.)
11.1.2
The first two hold frames aft of the forepeak bulkhead are to have a section modulus at least 21/2
times the SMF required by 5C-3-6/5.13.
Where major longitudinal structures within the forepeak do not terminate in way of the hold
framing, no special arrangements are required.

FIGURE 5
Transition Zone

Grea
t
2.5d er of
or 3
s

Side
Shel Bracket
l

Improved Cope Hole

Extension Piece
s

Stiffener
d

No. 1 Hold Forepeak tank

or space

Collision
Bulkhead

13 Forebody Strengthening for Slamming

13.1 General
Where the hull structure is subject to slamming as specified in 5C-3-3/11, proper strengthening may be
required as outlined below.

13.3 Bottom Slamming

13.3.1 Bottom Plating (2001)
When bottom slamming as specified in 5C-3-3/11.1 is considered, the bottom structure in the
region of the flat of bottom forward of 0.25L measured from the FP is to be in compliance with the
following requirements.
The net thickness of the flat of bottom plating forward of 0.25L measured from the FP is not to be
less than that obtained from the following equation:

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 6 Hull Structure Beyond 0.4L Amidships 5C-3-6

t = 0.73s(k2 k3 ps/f)1/2 in mm (in.)

where
s = spacing of longitudinal or transverse stiffeners, in mm (in.)
k2 = 0.5 k2 for either transversely or longitudinally stiffened plating
k3 = 0.74

k = (3.075 (α)1/2 − 2.077)/(α + 0.272), (1 ≤ α ≤ 2)

= 1.0 (α > 2)
α = aspect ratio of the panel (longer edge/shorter edge)
ps = the design slamming pressure = ku psi
For determination of t, the pressure ps is to be taken at the center of the supported panel.
psi = nominal bottom slamming pressure, as specified in 5C-3-3/11.1.1, in N/cm2
(kgf/cm2, lbf/in2)
The maximum nominal bottom slamming pressure occurring along the vessel is to be applied to
the bottom plating between the foremost extent of the flat of bottom and 0.125L from the FP. The
pressure beyond this region may be gradually tapered to the longitudinal location where the nominal
slamming pressure is calculated as zero.
ku = slamming load factor = 1.1

f = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)

= 0.85 Sm fy
Sm and fy are as defined in 5C-3-4/7.3.1.

13.3.2 Bottom Longitudinals and Stiffeners

The section modulus of the stiffener including the associated effective plating on the flat of bottom
forward of 0.25L measured from the FP is not to be less than that obtained from the following equation:
SM = M/fb in cm3 (in3)

M = 1000pssl2/k in N-cm (kgf-cm, lbf-in)

where
k = 16 (16, 111.1)
ps = the design slamming pressure = ku psi

For determination of M, the pressure ps is to be taken at the midpoint of the span l.

psi = nominal bottom slamming pressure, as specified in 5C-3-3/11.1.1, in N/cm2
(kgf/cm2, lbf/in2)
The maximum nominal bottom slamming pressure occurring along the vessel is to be applied to
the bottom plating between the foremost extent of the flat of bottom and 0.125L from the FP. The
pressure beyond this region may be gradually tapered to the longitudinal location where the nominal
slamming pressure is calculated as zero.
ku = slamming load factor = 1.1
s = spacing of longitudinal or transverse stiffeners, in mm (in.)
l = the unsupported span of the stiffener, in m (ft)

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 6 Hull Structure Beyond 0.4L Amidships 5C-3-6

fb = 0.9 Sm fy for transverse and longitudinal stiffeners in the region forward of

0.125L, measured from the FP
= 0.8 Sm fy for longitudinal stiffeners in the region between 0.125L and 0.25L,
measured from the FP
The effective breadth of plating be is as defined in 5C-3-4/7.5.
Struts connecting the bottom and inner bottom longitudinals are not to be fitted.
13.3.3 Supporting Members
The thickness of floors, girders and partial girders/floors, if any, are to be checked against the
expected shear forces in the region of the flat of bottom forward of 0.25L measured from the FP in
accordance with the formula in 5C-3-6/3.5. In this case nominal pressure, p, may be taken as:

∑ bi* s 3i
p=c p s, i = 1...N, but not less than 0.5ps
∑ 0.5bsi s 3i
where
c = 1.185 × 10-3 L + 0.485 for SI and MKS units (3.612 × 10-4 L + 0.485 for US
units)
ps = the maximum bottom slamming pressure within the particular double bottom
panel
= ku psi
psi = nominal bottom slamming pressure, as specified in 5C-3-3/11.1.1, in kN/m2
(tf/m2, Ltf/ft2)
ku = slamming loading factor = 1.0
bi* = half width of flat of bottom at the i-th floor in the double bottom panel, in m
(ft), but should not be greater than 0.5bsi
bsi = unsupported width of the i-th floor in the double bottom panel, in m (ft)
s3i = sum of one-half of floor spacings on both sides of the i-th floor, in m (ft)
N = number of floors in the double bottom panel
L is as defined in 3-1-1/3.1.
The permissible shear stress may be taken as 0.5 Sm fy.

13.5 Bowflare Slamming

When bowflare slamming as specified in 5C-3-3/11.3 is considered, the side shell structure above the
waterline in the region between 0.0125L and 0.25L from the FP is to be in compliance with the following
requirements.
13.5.1 Side Shell Plating (1999)
The net thickness of the side shell plating between 0.0125L and 0.25L from the FP is not to be less
than t1 or t2, whichever is greater, obtained from the following equations:

t1 = 0.73s(k1 ps /f1)1/2 in mm (in.)

t2 = 0.73s(k2 ps /f2)1/2 in mm (in.)

where
ps = the design slamming pressure = ku pij
pij = nominal bowflare slamming pressure, as specified in 5C-3-3/11.3.1, at the
center of the supported panel under consideration, in N/cm2 (kgf/cm2, lbf/in2)

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 6 Hull Structure Beyond 0.4L Amidships 5C-3-6

ku = slamming load factor = 1.1

f1 = 0.85 Sm fy for side shell plating forward of 0.125L from the FP, in N/cm2
(kgf/cm2, lbf/in2)
= 0.75 Sm fy for side shell plating in the region between 0.125L and 0.25L from
the FP, in N/cm2 (kgf/cm2, lbf/in2)
f2 = 0.85 Sm fy, in N/cm2 (kgf/cm2, lbf/in2)
s, k1, k2, Sm and fy are as defined in 5C-3-6/13.3 above.

13.5.2 Side Longitudinals and Stiffeners

The section modulus of the stiffener, including the associated effective plating, is not to be less
than obtained from the following equation:
SM = M/fb in cm3 (in3)

M = 1000pssl2/k in N-cm (kgf-cm, lbf-in)

where
k = 16 (16, 111.1)
l = unsupported span of the stiffener, in m (ft)
ps = the maximum slamming pressure, in N/cm2 (kgf/cm2, lbf/in2), as defined in
5C-3-6/13.5.1, at the midpoint of the span l
s and fb are as defined in 5C-3-6/13.3.2 above.
The effective breadth of plating, be, is as defined in 5C-3-4/7.5.

13.5.3 Side Transverses and Side Stringers (1 July 2008)

For the region between 0.0125L and 0.25L from the FP, the net section modulus and sectional area
requirements for side transverses and side stringers in 5C-3-6/7 are to be met with the bow flare
slamming pressure as specified in 5C-3-3/11.3.1 and with the permissible bending stress of
fb = 0.64Sm fy and the permissible shear stress of fs = 0.38Sm fy.

466 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
PART Section 7: Cargo Safety and Vessel Systems

5C
CHAPTER 3 Vessels Intended to Carry Ore or Bulk Cargoes
(150 meters (492 feet) or more in Length)

SECTION 7 Cargo Safety and Vessel Systems

1 Application
Provisions of Part 5C, Chapter 3, Section 7 (referred to as Section 5C-3-7) apply to vessels intended to
carry ore or solid bulk cargoes in respect of the hazards of the cargo carried. They form a part of the necessary
condition for assigning the class notation Bulk Carrier or Ore Carrier. The provisions of Part 4,
specifying conditions for assigning the machinery class notation AMS (see 4-1-1/1.5), are applicable to
these vessels in addition to the provisions of this section.
Attention is directed to the requirements of the IMO BC Code which may be prescribed by the vessel’s
Flag Administration. If requested by the vessel’s owner and authorized by the Flag Administration, ABS
will review plans and carry out surveys for purposes of verifying compliance with the Code on behalf of
the Administration.

3 Bulk Cargo Spaces

3.1 Fire Protection

Except for cargoes in 5C-3-7/3.3, cargo spaces of vessels of 2,000 gross tonnage and upwards are to be
protected by a fixed gas fire-extinguishing system complying with the provisions of 4-7-3/3 or by a fire
extinguishing system which gives equivalent protection.

3.3 Vessels Carrying Low Fire Risk Cargoes (2012)

Cargo spaces of any vessel if constructed and solely intended for carrying ore, coal, grain, unseasoned
timber, non-combustible cargoes or cargoes which constitute a low fire risk may be exempt from the
requirements of 5C-3-7/3.1. Such exemptions may be granted only if the vessel is fitted with steel hatch
covers and effective means of closing all ventilators and other openings leading to the cargo spaces.
Vessels with an exemption are to be distinguished in the Record as suitable for carriage of low fire risk
cargoes only. See also 4-7-2/7.
In accordance with IMO MSC/Circ.1146 List of solid bulk cargoes which are non-combustible or constitute a
low fire risk or for which a fixed gas fire extinguishing system is ineffective, the following solid bulk
cargoes may be regarded as non-combustible or constitute a low fire risk:
• Cargoes listed in IMO BC Code Appendix A List of bulk materials which may liquefy: all.
• Cargoes listed in IMO BC Code Appendix B List of bulk materials possessing chemical hazards: only
the following:
- Aluminum smelting by-products
- Aluminum ferrosilicon powder (including briquettes)
- Aluminum silicon powder, uncoated
- Calcined pyrides (Pyritic ash)
- Direct reduced iron briquettes, hot moulded

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 7 Cargo Safety and Vessel Systems 5C-3-7

- Ferrophospherous (including briquettes)

- Ferrosilicon with 25% to 30% silicon, or 90% or more silicon (including briquettes)
- Ferrosilicon with more than 30% but less than 90% silicon (including briquettes)
- Fluorspar (calcium fluoride)
- Lime (unslaked)
- Magnesia (Unslaked)
- Peat moss
- Petroleum coke (when loaded and transported under the provisions of the BC Code)
- Pitch prill
- Radioactive material, low specific activity material (LSA-1)
- Radioactive material, surface contaminated objects (SCO-1)
- Silicomanganese
- Sulfur (lump or coarse grained powder)
- Vanadium ore
- Woodchips with moisture content of 15% or more
- Wood pulp pellets with moisture content of 15% or more
- Zinc ashes
• Cargoes listed in IMO BC Code Appendix C List of bulk materials which are neither liable to liquefy
nor to possess chemical hazards: all.

3.5 Vessels Intended to Carry Solid Dangerous Goods in Bulk

3.5.1 General
Bulk cargo holds intended for the carriage of dangerous goods are to comply with the following
tabulated requirements, except when carrying dangerous goods in limited quantities (as defined in
section 18 of the General Introduction of IMDG Code):
• 5C-3-7/Table 1 provides a description of the list of dangerous goods as defined in IMDG
Code.
• 5C-3-7/Table 2 provides the application of the requirements described in 4-7-2/7.3 to the
different classes of solid dangerous goods in bulk.
3.5.2 Cargoes for which Fixed Gas Fire-extinguishing System is Ineffective
A fixed gas fire-extinguishing system is considered ineffective for the following solid bulk
cargoes, for which a fire-extinguishing system giving equivalent protection is to be available:
Aluminum nitrate Magnesium nitrate
Ammonium nitrate Potassium nitrate
Ammonium nitrate fertilizers Sodium nitrate
Barium nitrate Chilean natural nitrate
Calcium nitrate Sodium nitrate and potassium nitrate, mixture
Lead nitrate Chilean natural potassic nitrate

468 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 7 Cargo Safety and Vessel Systems 5C-3-7

TABLE 1
Dangerous Goods Classes
CLASS SUBSTANCE
1 Explosives
(1.1 through 1.6)
2.1 Flammable gases (compressed, liquefied or dissolved under pressure)
2.2 Non flammable gases (compressed, liquefied or dissolved under pressure)
2.3 Toxic gases
3 Flammable liquids
(3.1 through 3.3)
4.1 Flammable solids
4.2 Substances liable to spontaneous combustion
4.3 Substances which, in contact with water, emit flammable gases
5.1 Oxidizing substances
5.2 Organic peroxides
6.1 Toxic substances
6.2 Infectious substances
7 Radioactive materials
8 Corrosives
9 Miscellaneous dangerous substances and articles, that is, any substance which experience
has shown, or may show, to be of such a dangerous character that the provisions for
dangerous substance transportation are to be applied.

TABLE 2
Application of the Requirements to Different Classes
of Solid Dangerous Goods in Bulk
4-7-2/… Requirements Dangerous Goods Classes
4.1 4.2 4.3(1) 5.1 6.1 8 9
7.3.1(a) Availability of water x x - x - - x
7.3.1(b) Quantity of water x x - x - - x
7.3.2 Sources of ignition x x (2) x x (3) - - x (3)
7.3.4(a) Number of air changes - x (2) x - - - -
(4)
7.3.4(b) Ventilation fan x x (2) x x (2),(4) - - x (2),(4)
7.3.4(c) Natural ventilation x x x x x x x
7.3.6 Personnel protection x x x x x x x
(2)
7.3.8 Insulation of machinery space x x x x - - x (5)
boundary
Notes
1 The hazards of substances in this class which may be carried in bulk are such that special
consideration must be given to the construction and equipment of the vessels involved in
addition to meeting the requirements enumerated in this table. Complete design and
installation details are to be submitted for review in each case.
2 Only applicable to Seedcake containing solvent extractions, to Ammonia nitrate, and to
Ammonia nitrate fertilizers.
3 Only applicable to Ammonia nitrate and to Ammonia nitrate fertilizers. However, a degree
of protection in accordance with standards contained in IEC 79 Electrical Apparatus for
Explosive Gas Atmosphere is sufficient.
4 Only suitable wire mesh guards are required.
5 The requirements of the Code of Safe Practice for Solid Bulk Cargoes (IMO Resolution
A.434(XI), as amended), are sufficient.

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Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 7 Cargo Safety and Vessel Systems 5C-3-7

3.7 Vessels Intended to Carry Coal in Bulk

3.7.1 Flag Administration (1998)
Attention is directed to the requirements for the carriage of coal in bulk in the IMO BC Code and
their application as may be prescribed by the vessel’s flag administration. If requested by the
vessel’s owner and authorized by the Administration, ABS will review the plans and carry out
surveys in accordance with the above Code on behalf of the Administration.
3.7.2 Hazardous Areas
Areas where flammable or explosive gases, vapors or dust are normally present or likely to be
present are known as hazardous areas. For vessels intended to carry coal in bulk, the following
areas are to be regarded as hazardous areas:
• Cargo hold spaces,
• Enclosed and semi-enclosed spaces having a direct opening to cargo hold space, and
• Open deck areas within 3 m (10 ft) of cargo hold mechanical ventilation outlets.
3.7.3 Installation of Electrical Equipment in Hazardous Areas
Electrical equipment installed in hazardous areas, identified in 5C-3-7/3.7.2, is to be:
i) Intrinsically safe type (Ex ia or ib);
ii) Flame-proof (explosion-proof) type (Ex d Group IIA T4);
iii) Pressurized or purged type (Ex p); or
iv) Increased safety type (Ex e) in open deck hazardous areas only.
See also 4-8-3/13 and 4-8-4/27.
3.7.4 Installation of Internal Combustion Engines in Hazardous Areas
Where essential for the operation of the vessel, the installation of internal combustion engines in
hazardous areas, identified in 5C-3-7/3.7.2, may be permitted. This is subject to the elimination of
all sources of ignition from the installation; the engine exhaust being led outside the hazardous
areas, and the engine air intake being not less than 3 m (10 ft) from the hazardous areas. Complete
details are to be submitted for review in each case.
3.7.5 Cargo Hold Atmosphere Measuring Instruments (1998)
3.7.5(a) Required measurements. Instruments are to be provided to measure the following in the
cargo holds:
• Concentration of methane in the atmosphere;
• Concentration of oxygen in the atmosphere;
• Concentration of carbon monoxide in the atmosphere; and
• pH value of cargo hold bilge samples.
In addition, where self-heating coals are to be carried, it is recommended that consideration be
given by the Owner/designer to provide the means for measuring the temperature of the cargo in
the range of 0°C (32°F) to 100°C (212°F) during loading operations and during the voyage.
Means for calibration of the above instruments are to be provided onboard.
3.7.5(b) Arrangements of measurement. The required measurements and their readings are to be
obtainable without entry into the cargo hold, and without introducing a source of ignition or
otherwise endangering the cargo and cargo hold atmosphere. Instruments for measuring methane,
oxygen and carbon monoxide concentrations are to be provided, together with an aspirator,
flexible connection, a length of tubing and means for sealing the sampling hole, in order to enable
a representative sample to be obtained from within the hatch cover surroundings. Alternative
means for obtaining a representative sample will be considered.

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Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 7 Cargo Safety and Vessel Systems 5C-3-7

3.7.5(c) Sampling points. Sampling points are to be provided for each hold, one on the port side
and the other on the starboard side of the hatch cover, as near to the top of the hatch cover as
possible. Each sampling point is to be fitted with a screw cap or equivalent and a threaded stub of
approximately 12 mm (0.5 in.) bore welded to the side of the hatch cover to prevent ingress of
water and air. Alternative sampling point arrangements/details will be considered.
3.7.6 Warning Plate (1998)
A permanent warning plate is to be installed in conspicuous places in cargo areas to state that
smoking, naked flames, burning, cutting, chipping, welding or other sources of ignition are prohibited.
3.7.7 Hot Areas
Coal is not to be stowed adjacent to hot surfaces having a temperature of 45°C or above. Spaces
adjacent to cargo holds that are likely to be hot, such as heated fuel oil tanks, are to be provided
with suitable measures to prevent the common boundaries from being raised to a temperature
beyond that considered safe for the carriage of the coal.

3.9 Vessels Intended to Carry Materials Hazardous Only in Bulk

Vessels intended to carry materials hazardous only in bulk (MHB), other than coal as addressed in
5C-3-7/3.7, are to comply with the recommendations of the Code of Safe Practice for Solid Bulk Cargoes
(IMO Resolution A.434(XI), as amended) and the intent of 5C-3-7/3.7.

3.11 Cable Support (2005)

Cable inside of the vertical cable conduit pipe is to be suitably supported, e.g., by sand-filling or by
strapping to a support wire. Alternatively, the cable inside of the vertical conduit pipe may be accepted
without provided support if the mechanical strength of the cable is sufficient to prevent cable damage due
to the cable weight within the conduit pipe under continuous mechanical load. Supporting documentation
is to be submitted to verify the mechanical strength of the cable with respect to the cable weight inside of
the conduit.

5 Hold Piping
Where the cargo hold is used alternately for dry cargo or ballast water, the following arrangements are to
be made:
i) When the hold is used for ballast, the bilge suction is to be blanked off. Suitable means of venting
and overflow, in accordance with the intent of 4-6-4/9, is to be provided.
ii) When the cargo hold is used for dry cargo, the ballast line is to be blanked off and the bilge
suction is to be effective.

7 Self-unloading Cargo Gear

Dry bulk cargo vessels are to meet the following additional requirements when fitted with self-unloading
cargo handling equipment.

7.1 Fail-safe Arrangements and Safety Devices

Fail-safe arrangements and safety devices are to be provided on the self-unloading equipment. A system is
considered fail-safe if a component failure or loss of power will result in a controlled securing of the
equipment or control of movement so as not to endanger personnel.

7.3 Hydraulic Piping Installations

The passage of self-unloading system hydraulic pipes through cargo holds is to be limited to only that
which is necessary for operational purposes. Pipes installed within cargo holds are to be protected from
mechanical damage.
System connection to other hydraulic systems is subject to special consideration. Failure in any one part of
the self-unloading hydraulic system is not to cause the failure of other parts of the self-unloading system or
of other ship’s systems.

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Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Section 7 Cargo Safety and Vessel Systems 5C-3-7

7.5 Equipment in Hazardous Areas

For requirements regarding the installation of equipment associated with the self-unloading cargo gear in
hazardous areas, see 5C-3-7/3.7, as applicable.

7.7 Self-unloading Gear Controls and Alarms

7.7.1 General
Where vessels are equipped with self-unloading systems, controls are to be provided for the safe
operation of the self-unloading system. These controls are to be clearly marked to show their
functions. Energizing the power unit at a location other than the cargo control station is not to set
the gear in motion.
7.7.2 Monitors
As appropriate, monitoring is to indicate system operational status (operating or not operating),
availability of power, overload alarm, air pressure, hydraulic pressure, electrical power or current,
motor running and motor overload, and brake mechanism engagement.
7.7.3 Emergency Shutdowns
Remote emergency shutdowns of power units for self-unloading equipment are to be provided
outside of the power unit space so that they may be stopped in the event of fire or other
emergency. Where remote controls are provided for cargo gear operation, means for the local
emergency shutdowns are to be provided.

9 Draining and Pumping Forward Spaces in Bulk Carriers (2005)

9.1 Application
This requirement applies to bulk carriers constructed generally with single deck, top-side tanks and hopper
side tanks in cargo spaces intended primarily to carry dry cargo in bulk, and includes such types as ore
carriers and combination carriers.

9.3 Availability of Pumping Systems for Forward Spaces (2006)

On bulk carriers, the means for draining and pumping ballast tanks forward of the collision bulkhead and
bilges of dry spaces, any part of which extends forward of the forward most cargo hold, are to be capable
of being brought into operation from a readily accessible enclosed space, the location of which is accessible
from the navigation bridge or propulsion machinery control position without traversing exposed freeboard
or superstructure decks. Where pipes serving such tanks or bilges pierce the collision bulkhead, valve operation
by means of remotely operated actuators may be accepted, as an alternative to the valve control specified
in 4-6-2/9.7.3, provided that the location of such valve controls complies with the above arrangement.

9.5 Dewatering Capacity

The dewatering system for ballast tanks located forward of the collision bulkhead and for bilges of dry
spaces any part of which extends forward of the foremost cargo hold is to be designed to remove water
from the forward spaces at a rate not less than that determined from the following equation:
Q = 320A m3/hr
Q = 0.908A gpm
where
A = cross-sectional area, in m2 (in2), of the largest air pipe or ventilator pipe connected
from the exposed deck to a closed forward space that is required to be dewatered by
these arrangements

472 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
PART Appendix 1: Guide for Fatigue Strength Assessment of Bulk Carriers

5C
CHAPTER 3 Vessels Intended to Carry Ore or Bulk Cargoes
(150 meters (492 feet) or more in Length)

APPENDIX 1 Guide for Fatigue Strength Assessment of Bulk

Carriers

1 General

1.1 Note
This Guide provides a designer-oriented approach to fatigue strength assessment which may be used, for
certain structural details, in lieu of more elaborate methods such as spectral fatigue analysis. The term
assessment is used here to distinguish this approach from the more elaborate analysis.
The criteria in this Guide are developed from various sources including the Palmgren-Miner linear damage
model, S-N curve methodologies, a long-term environment data of the North-Atlantic Ocean (Walden’s
Data), etc., and assume workmanship of commercial marine quality acceptable to the Surveyor. The
capacity of structures to resist fatigue is given in terms of permissible stress range to allow designers the
maximum flexibility possible.
While this is a simplified approach, a good amount of effort is still required in applying these criteria to the
actual design. For this reason, a PC-based software has been developed and is available to the clients.
Interested parties are kindly requested to contact the nearest ABS plan approval office for more information.

1.3 Applicability (1996)

The criteria in this Guide are specifically written for bulk carriers to which Part 5C, Chapter 3 is applicable.
For vessels intended to carry oil/bulk cargoes/ores, Appendix 5C-1-A1 is also applicable.

1.5 Loadings (1996)

The criteria have been written for ordinary wave-induced motions and loads. Other cyclic loadings which
may result in significant levels of stress ranges over the expected lifetime of the vessel are also to be
considered by the designer.
Where it is known that a vessel will be engaged in long-term service on a route with a more severe
environment, the fatigue strength assessment criteria in this Guide are to be modified accordingly.

1.7 Effects of Corrosion (1996)

To account for the mean wastage throughout the service life, the total stress range calculated using the net
scantlings (i.e., deducting nominal design corrosion values, see 5C-3-2/Table 1) is modified by a factor cf.
See 5C-3-A1/9.1.1.

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1.9 Format of the Criteria (1996)

The criteria in this Guide are presented as a comparison of fatigue strength of the structure (capacity) and
fatigue inducing loads (demands) as represented by the respective stress ranges. In other words, the
permissible stress range is to be not less than the total stress range acting on the structure.
5C-3-A1/5 provides the basis to establish the permissible stress range for the combination of the fatigue
classification and typical structural joints of bulk carriers. 5C-3-A1/7 presents the procedures to be used to
establish the applied total stress range. 5C-3-A1/11 provides typical stress concentration factors (SCFs)
and guidelines for direct calculation of the required SCFs. 5C-3-A1/13 provides the guidance for
assessment of stress concentration factors and the selection of compatible S-N data where a fine mesh
finite element approach is used.

3 Connections to be Considered for the Fatigue Strength Assessment

3.1 General (1996)

These criteria have been developed to allow consideration of a broad variation of structural details and
arrangements so that most of the important structural details anywhere in the vessel can be subjected to an
explicit (numerical) fatigue assessment using these criteria. However, where justified by comparison with
details proven satisfactory under equal or more severe conditions, an explicit assessment can be exempted.

3.3 Guidance on Locations (1996)

As a general guidance for assessing fatigue strength for a bulk carrier, the following connections and
locations are to be considered:
3.3.1 Connections of Hold Frame
All typical end connections of hold frames to the upper and lower wing tanks in the ballast, heavy
cargo and general cargo holds, as illustrated for Class F2 item 2 in 5C-3-A1/Table 1.

3.3.2 Connections of Longitudinal Stiffeners to Transverse Web/Floor and to Transverse Bulkhead

3.3.2(a) Two (2) to three (3) selected side longitudinals in the upper and lower wing tanks for the
midship region and also in the region between 0.15L and 0.25L from the FP
3.3.2(b) One (1) to two (2) selected longitudinals from each of the following groups:
• Deck longitudinals, bottom longitudinals, inner bottom longitudinals and longitudinals on the
slope/longitudinal bulkheads.
• One longitudinal on the inner skin longitudinal bulkhead within 0.10D from the deck is to be
included.
For these structural details, the fatigue assessment is to be first focused on the flange of the
longitudinal at the rounded toe welds of attached flat bar stiffeners and brackets, as illustrated for
Class F item 2) and Class F2 item 1) in 5C-3-A1/Table 1.
Then, the critical spots on the web plate cut-out, on the lower end of the stiffener as well as the weld
throat are also to be checked for the selected structural detail. For illustration see 5C-3-A1/11.3.1
and 5C-3-A1/11.3.2(a), 5C-3-A1/11.3.2(b) and 5C-3-A1/11.3.2(c).
Where the longitudinal stiffener end bracket arrangements are different on opposing sides of a
transverse web or transverse bulkhead, both configurations are to be checked.
3.3.3 End Connections of Transverse Bulkhead
Connections of transverse bulkhead plating (corrugated) to the stools or the sloping longitudinal
plates.

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3.3.4 Shell, Bottom or Bulkhead Plating at Connections to the Sloping Longitudinal Bulkhead
Plating, Transverse Webs or Floors
3.3.4(a) One (1) to two (2) selected locations of side shell plating at connections of the sloping
bulkhead plating and hold frames, and near the summer LWL amidships, and also between 0.15L
and 0.25L from the FP
3.3.4(b) One (1) to two (2) selected locations in way of bottom, inner bottom and lower strakes of
the sloping longitudinal bulkhead of the lower wing tanks amidships, respectively.
For this structural detail, the value of fR, the total stress range as specified in 5C-3-A1/9.1, is to be
determined from fine mesh F.E.M. analyses for the combined load cases, as specified for Zone B
in 5C-3-A1/7.5.2.
3.3.5 End Bracket Connections for Transverses and Girders
One (1) to two (2) selected locations in the midship region for each type of bracket configuration
3.3.6 Other Regions and Locations
Other regions and locations, highly stressed by fluctuating loads, as identified from structural
analysis

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TABLE 1
Fatigue Classification for Structural Details (1996)
Long-term
Distribution Permissible Stress
Parameter Range
Class
Designation Description γ kgf/mm2
B Parent materials, plates or shapes as-rolled or drawn, 0.7 92.2*
with no flame-cut edges 0.8 75.9
0.9 64.2
1.0 55.6

C 1) Parent material with automatic flame-cut edges 0.7 79.2

0.8 63.9
2) Full penetration seam welds or longitudinal fillet welds 0.9 53.3
made by an automatic submerged or open arc process, 1.0 45.7
and with no stop-start positions within the length

D 1) Full penetration butt welds made either manually or by 0.7 59.9

an automatic process other than submerged arc, from 0.8 47.3
both sides, in downhand position 0.9 38.9
1.0 32.9
2) Welds in C-2) with stop-start positions within the length

E 1) Full penetration butt welds made by other processes than 0.7 52.8
those specified under D-1) 0.8 41.7
0.9 34.2
2) Full penetration butt welds made from both sides 1.0 29.0
between plates of unequal widths or thicknesses
2a 2b
E
4 1
TAPER
E
1 3
TAPER

3) welds of brackets and stiffeners to web plate of girders

*1) The permissible stress range cannot be taken greater than two times the specified minimum tensile
strength of the material.
2) To obtain the permissible stress range in SI and U.S. Units, the conversion factors of 9.807 (N/mm2) and
1422 (lbf/in2) can be used, respectively.

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TABLE 1 (continued)
Fatigue Classification for Structural Details (1996)
Long-term
Distribution Permissible Stress
Parameter Range
Class
Designation Description γ kgf/mm2
F 1) Full penetration butt welds made on a permanent backing 0.7 44.7
strip 0.8 35.3
0.9 29.0
1.0 24.5
2) Rounded fillet welds as shown below

2a 2b
TRANSVERSE OR FLOOR

Y
F
F F
LONGITUDINAL

SHELL OR BOTTOM PLATING F

"Y" IS REGARDED AS A NON-LOAD CARRYING MEMBER

3) Welds of brackets and stiffeners to flanges

EDGE DISTANCE ≥ 10mm

4) Attachments on plate or face plate
F

EDGE DISTANCE ≥ 10mm

(Class G for edge distance < 10 mm)

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TABLE 1 (continued)
Fatigue Classification for Structural Details (1996)
Long-term
Distribution Permissible Stress
Parameter Range
Class
Designation Description γ kgf/mm2
F2 1) Fillet welds as shown below with rounded welds and no 0.7 39.3
undercutting
0.8 31.1
0.9 25.5
1.0 21.6
1a 1b

Y Y

F F F F
2 2 2 2

"Y" is a non-load carrying member

2) Fillet welds with any undercutting at the corners dressed out by local grinding

2a 2b

F2

F2

F2 F2

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TABLE 1 (continued)
Fatigue Classification for Structural Details (1996)
Long-term
Distribution Permissible Stress
Parameter Range
Class
Designation Description γ kgf/mm2
G 1) Fillet welds in F2-1) without rounded toe welds or with 0.7 32.8
limited minor undercutting at corners or bracket toes 0.8 25.9
0.9 21.3
1.0 18.0
2) Fillet welds in F2-2) with minor undercutting
3) Doubler on face plate or flange
G

I I

I-
G I G

W 1) Fillet welds in G-3) with any undercutting at the toes 0.7 28.3
0.8 22.3
0.9 18.4
2) Fillet welds—weld throat 1.0 15.5

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5 Permissible Stress Range

5.1 Assumptions (1996)

The fatigue strength of a structural detail under the loads specified here in terms of a long term, permissible
stress range, is to be evaluated using the criteria contained in this section. The key assumptions employed
are listed below for guidance.
• A linear cumulative damage model (i.e., Palmgren-Miner’s Rule) has been used in connection with the
S-N data in 5C-3-A1/Figure 1 (extracted from Ref. 1*).
• Cyclic stresses due to the loads in 5C-3-A1/7 have been used and the effects of mean stress have been
ignored.
• The target design life of the vessel is taken to be 20 years.
• The long-term stress ranges on a detail can be characterized using a modified Weibull probability
distribution parameter (γ).
• Structural details are classified and described in 5C-3-A1/Table 1, “Fatigue Classification of Structural
Details”.
• Simple nominal stress (e.g., determined by P/A and M/SM) is the basis of fatigue assessment rather
than more localized peak stress in way of weld.
The structural detail classification in 5C-3-A1/Table 1 is based on joint geometry and direction of the
dominant load. Where the loading or geometry is too complex for a simple classification, a finite element
analysis of the details is to be carried out to determine stress concentration factors. 5C-3-A1/13 contains
guidance on finite element analysis modeling to determine stress concentration factors for weld toe
locations that are typically found at longitudinal stiffener end connections.
* Ref 1: “Offshore Installations: Guidance on Design, Construction and Certification”, Department of Energy, U.K.,
Fourth Edition—1990, London: HMSO

5.3 Criteria (1996)

The permissible stress range obtained using the criteria in 5C-3-A1/5 is to be not less than the fatigue
inducing stress range obtained from 5C-3-A1/7.

5.5 Long Term Stress Distribution Parameter, γ (1996)

In 5C-3-A1/Table 1, the permissible stress range is given as a function of the long term distribution
parameter, γ, as defined below.
γ = msγo
where
ms = 1.05 for deck and bottom structures of vessels with a bowflare parameter Aγ = 27
as defined in 5C-3-3/11.3, and vessels with bottom slamming (draft at FP =
0.03L) as defined in 5C-3-3/11.1.
= 1.02 for deck and bottom structures of vessels with a bowflare parameter Aγ = 24
and vessels subject to bottom slamming (draft at FP = 0.035L)
= 1.0 for structures elsewhere, and all structures of vessels without bottom and
bowflare slamming (Aγ ≤ 21, draft at FP ≥ 0.04L)
For intermediate values of Aγ and draft at FP, ms may be obtained by linear
interpolation. For Aγ > 27 and draft at FP < 0.03L, ms is to be determined by direct
calculations
γo = 1.40 − 0.2αL0.2 for 150 < L ≤ 305 m
= 1.54 − 0.245α0.8L0.2 for L > 305 m
γo = 1.40 − 0.16αL 0.2
for 492 < L ≤ 1001 ft
= 1.54 − 0.19α0.8L0.2 for L > 1001 ft

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α = 1.0 for deck structures, including side shell and longitudinal bulkhead structures
within 0.1D from the deck
= 0.93 for bottom structures, including inner bottom, and side shell and longitudinal
bulkhead structures within 0.1D from the bottom
= 0.86 for side shell and longitudinal bulkhead structures within the region of 0.25D
upward and 0.3D downward from the mid-depth
= 0.80 for hold frames and transverse bulkhead structures
α may be linearly interpolated for side shell and longitudinal bulkhead structures between 0.1D and 0.25D
(0.2D) from the deck (bottom).
L and D are the vessel’s length and depth and as defined in 3-1-1/3.1 and 3-1-1/7.3, respectively.

5.7 Permissible Stress Range (1996)

5C-3-A1/Table 1 contains a listing of the permissible stress ranges, PS, for various categories of structural
details with 20-year minimum design fatigue life. The permissible stress range is determined for the
combination of the types of connections/details, the direction of dominant loading and the parameter, γ, as
defined in 5C-3-A1/5.5. Linear interpolation may be used to determine the values of permissible stress
range for a value of γ between those given.
(2003) For vessels designed for a fatigue life in excess of the minimum design fatigue life of 20 years (see
5C-3-1/1.2), the permissible stress ranges (PS) calculated above are to be modified by the following equation:
PS[Yr] = C(20/Yr)1/m PS
where
PS[Yr] = permissible stress ranges for the design fatigue life for the Yr
Yr = target value of “design fatigue life” set by the applicant in five (5) year increments
m = 3 for Class D through W of S-N curve, 3.5 for Class C or 4 for Class B curves
C = correction factor related to target design fatigue life considering the two-segment S-N
curves (see 5C-3-A1/Table 1A).

TABLE 1A
Coefficient, C
Long-term Stress Target Design Fatigue S-N Curve Classes
Distribution Parameter, γ Life, years, Yr B C D through W
0.7 20 1.000 1.000 1.000
30 1.004 1.006 1.011
40 1.007 1.012 1.020
50 1.010 1.016 1.028
0.8 20 1.000 1.000 1.000
30 1.005 1.008 1.014
40 1.009 1.015 1.025
50 1.013 1.021 1.035
0.9 20 1.000 1.000 1.000
30 1.006 1.010 1.016
40 1.012 1.019 1.030
50 1.017 1.026 1.042
1.0 20 1.000 1.000 1.000
30 1.008 1.012 1.019
40 1.015 1.022 1.035
50 1.020 1.031 1.049
Note: Linear interpolations may be used to determine the values of C where Yr = 25, 35 and 45

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FIGURE 1
Basic Design S-N Curves (1995)

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FIGURE 1 (continued)
Basic Design S-N Curves (1995)
Notes (For 5C-3-A1/Figure 1)
a) Basic design S-N curves
The basic design curves consist of linear relationships between log(SB) and log(N). They are based upon a
statistical analysis of appropriate experimental data and may be taken to represent two standard deviations
below the mean line.
Thus, the basic S-N curves are of the form:
log(N) = log(K2) − m log(SB)
where
log(K2) = log(K1) − 2σ
N is the predicted number of cycles to failure under stress range SB;
K1 is a constant relating to the mean S-N curve;

σ is the standard deviation of log N;

m is the inverse slope of the S-N curve.
The relevant values of these terms are shown in the table below.
The S-N curves have a change of inverse slope from m to m + 2 at N = 107 cycles.
Details of basic S-N curves
K1 Standard deviation
Class K1 log10 loge m log10 loge K2
B 2.343 × 1015 15.3697 35.3900 4.0 0.1821 0.4194 1.01 × 1015
C 1.082 × 1014 14.0342 32.3153 3.5 0.2041 0.4700 4.23 × 1013
D 3.988 × 1012 12.6007 29.0144 3.0 0.2095 0.4824 1.52 × 1012
12
E 3.289 × 10 12.5169 28.8216 3.0 0.2509 0.5777 1.04 × 1012
F 1.726 × 1012 12.2370 28.1770 3.0 0.2183 0.5027 0.63 × 1012
F2 1.231 × 1012 12.0900 27.8387 3.0 0.2279 0.5248 0.43 × 1012
12
G 0.566 × 10 11.7525 27.0614 3.0 0.1793 0.4129 0.25 × 1012
W 0.368 × 1012 11.5662 26.6324 3.0 0.1846 0.4251 0.16 × 1012

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7 Fatigue Inducing Loads

7.1 General (1996)

This section provides: 1) the criteria to define the individual load components considered to cause fatigue
damage (see 5C-3-A1/7.3); 2) the load combination cases to be considered for different regions of the hull
containing the structural detail being evaluated (see 5C-3-A1/7.5) and 3) procedures to idealize the
structural components to obtain the total stress range acting on the structure.

7.3 Wave-induced Loads

The fatigue-inducing load components to be considered are those induced by the seaway. They are divided
into the following three groups:
• Hull girder wave-induced moments (vertical, horizontal and torsional), see 3-2-1/3.5 and 5C-3-3/5.
• External hydrodynamic pressures, and
• Internal cargo/liquid loads (including inertial loads and added static head due to ship’s motion), see
5C-3-3/5.5 and 5C-3-3/5.7.

7.5 Fatigue Assessment Zones and Controlling Load Combination (1996)

Depending on the location of the structural details undergoing the fatigue assessment, different combinations
of load cases are to be used to find the appropriate stress range as indicated below for indicated respective
zones.
7.5.1 Zone A
Zone A consists of deck and bottom structures; side shell and longitudinal bulkhead structures,
including the upper and lower wing tanks, within 0.1D (D is vessel’s molded depth) from deck
and bottom, respectively. For Zone A, stresses are to be calculated based on the wave induced
loads specified in 5C-3-3/Table 1, as follows.
7.5.1(a) Calculate dynamic component of stresses for load cases LC1 through LC4, respectively.
7.5.1(b) Calculate two sets of stress ranges, one each for the following two pairs of combined
loading cases.
LC1 and LC2, and
LC3 and LC4
7.5.1(c) Use the greater of the stress ranges obtained by 5C-3-A1/7.5.1(b).
7.5.2 Zone B
Zone B consists of side shell and all longitudinal bulkhead structures within the region between
0.25D upward and 0.30D downward from the mid-depth, hold frames and transverse bulkhead
structures. The total stress ranges for Zone B may be calculated based on the wave-induced loads
specified in 5C-3-3/Table 1 as follows:
7.5.2(a) Calculate dynamic component of stresses for load cases LC5 through LC10, respectively.
7.5.2(b) Calculate three sets of stress ranges, one each for the following three pairs of combined
loading cases.
LC5 and LC6,
LC7 and LC8, and
LC9 and LC10
However, for inner bottom, sloping bulkhead, inner skin and side shell of holds other than the
ballast hold, the stress range of LC9 and LC10 may be neglected.
7.5.2(c) Use the greater of the stress ranges obtained by 5C-3-A1/7.5.2(b).

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7.5.3 Transitional Zone

The transitional zone between Zone A and Zone B consists of side shell and all longitudinal
bulkhead structures between 0.1D and 0.25D (0.2D) from deck (bottom).
fR = fR(B) − [fR(B) − fR(A)] yu/0.15D for upper transitional zone

fR = fR(B) − [fR(B) – fR(A)] yl/0.1D for lower transitional zone

where
fR(A), fR(B) = the total stress ranges based on the combined load cases defined for Zone A
or Zone B, respectively
yu, yl = vertical distances from 0.25D (0.3D) upward (downward) from the mid-
depth to the location considered
7.5.4 Vessels with Either Special Loading Patterns or Special Structural Configuration
For vessels with either special loading patterns or special structural configurations/features, additional
load cases may be required for determining the stress range.

7.7 Primary Stress fd1 (1996)

fd1v and fd1h may be calculated by a simple beam approach. For assessing fatigue strength of side shell and
longitudinal bulkhead plating at welded connections, the value of wave-induced primary stress is to be
taken as that of maximum principal stresses at the location considered to account for the combined load
effects of the direct stresses and shear stresses. For calculating the value of fd1v for longitudinal deck
members, normal camber may be disregarded.
For Panamax class and other bulk carriers of length not greater than 230 meters, the primary stress range
fR1 may be calculated based on 85% of the wave-induced moments induced in 5C-3-3/5.3.

7.9 Secondary Stress f d2 (1996)

When a 3D structural analysis is not available, the secondary bending stress ranges may be obtained from
an analytic calculation or experimental data with appropriate boundary conditions. Otherwise, the secondary
bending stresses may be calculated using the approximate equations given below.
7.9.1 Double Bottom
The secondary longitudinal bending stress ranges in double bottom panels may be obtained from
the following equation:
fd2i = k1bk2bk3bpeb2ri/(iLiT)1/2 N/cm2 (kgf/cm2, lbf/in2)
where
fd2i = secondary longitudinal bending stress range in the structural member “i” at
the intersection with the transverse bulkhead, N/cm2 (kgf/cm2, lbf/in2)
k1b = 0.075 for bottom or inner bottom plating
= 0.068 for face plates, flanges and web plates
k2b = coefficients depending on apparent aspect ratio “ρb”

= as given in 5C-3-A1/Table 2 for ρb ≥ 1

= ρ b2 kb′ where kb′ is as given in 5C-3-A1/Table 3 for ρb < 1

ρb = (l/b)(iT /iL)1/4
k3b = coefficients given in 5C-3-A1/Table 4 depending on the number of
longitudinal girders in the double bottom and location of the longitudinal
member considered

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pe = effective average lateral pressure range on the double bottom panel for the
load case considered, as specified in 5C-3-A1/7.3, in N/cm2 (kgf/cm2, lbf/in2)
b = width of the double bottom panel (see also 5C-3-A1/Figure 2), in cm (in.)
l = length of the cargo hold being considered (see 5C-3-A1/Figure 2), in cm (in.)
iL, iT = unit moments of inertia of the double bottom panel in the longitudinal and
transverse directions, respectively, in cm3 (in3)
iL = IL/SL
iT = IT/ST
IL, IT = moments of inertia of equally spaced girders and floors, respectively,
including the effective width of plating and stiffeners attached to the
effective plating, in cm4 (in4)
SL, ST = spacing of bottom girders and floors, respectively, in cm (in.)
ri = distance between the horizontal neutral axis of the double bottom cross
section and the location of the structural element being considered (bending
lever arm – see 5C-3-A1/Figure 2), in cm (in.)
7.9.2 Double Sides
For double side’s structural members, the secondary longitudinal bending stress range at the
intersection with the transverse bulkhead may be obtained from the following equation.
fd2i = k1sk2sk3s pe h2ri /(iL iV)1/2 N/cm2 (kgf/cm2, lbf/in2)
where
fd2i = secondary longitudinal bending stress in the structural element “i”
k1s = 0.075 for shell or inner skin plating
= 0.068 for face plates, flanges, and web plates
k2s = coefficients depending on apparent aspect ratio “ρ”
= as given in 5C-3-A1/Table 5 for ρs ≥ 1

= ρ s2 ks′ where ks′ is as given in 5C-3-A1/Table 6 for ρs < 1

ρs = (l1/h)(iV /iL)1/4
k3s = coefficients given in 5C-3-A1/Table 7 depending on the number of side
stringers in the double side
pe = effective lateral pressure range, which is the maximum pressure (pressure
range) on the double side for the load case being considered, as specified in
5C-3-A1/7.3, in N/cm2 (kgf/cm2, lbf/in2)
h = height of the double side panel between upper and lower wing tanks (see also
5C-3-A1/Figure 2), in cm (in.)
l1 = length of the cargo hold being considered (see 5C-3-A1/Figure 2), in cm (in.)
iL, iV = unit moments of inertia of the double side panel in the longitudinal and
vertical directions, respectively, in cm3 (in3)
iL = IL/SL
iV = IV /SV
IL, IV = moments of inertia of equally spaced longitudinal stringers and web frames,
respectively, including the effective width of plating and stiffeners attached
to the effective plating, in cm4 (in4)

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SL, SV = spacing of longitudinal stringers and web frames, respectively, in cm (in.)

ri = distance between the vertical neutral axis of the double side cross section and
the structural member in question (bending lever arm – see 5C-3-A1/Figure 2,
in cm (in.)
7.9.3
For those connections specified in 5C-3-A1/3.3.2, the wave-induced secondary bending stress fd2
may be ignored.

7.11 Additional Secondary Stresses f d*2 and Tertiary Stresses fd3

7.11.1 Calculation of f d*2 (1997)

Where required, the additional secondary stresses acting at the flange of a longitudinal stiffener,
f d*2 , may be approximated by

f d*2 = CtCy M/SM N/cm2 (kgf/cm2, lbf/in2)

where
M = Cd psl2/12 N-cm (kgf-cm, lbf-in), at the supported ends of longitudinal
Where flat bar stiffeners or brackets are fitted, the bending moment, M, given above, may be
adjusted to the location of the brackets toe, i.e., Mx in 5C-3-4/Figure 4.
Where a longitudinal has remarkably different support stiffness at its two ends (e.g., a longitudinal
connected to a transverse bulkhead on one end), considerations are to be given to the increase of
bending moment at the joint.
Cd = 1.15 for longitudinal stiffener connections at the transverse bulkhead for
side longitudinals, deck longitudinals, and longitudinals on
longitudinal bulkheads.
= 1.0 elsewhere
p = wave induced local net pressure range, in N/cm2 (kgf/cm2, lbf/in2), for the
specified location and load cases at the mid-span of the longitudinal
considered
s = spacing of longitudinals/stiffeners, in cm (in.)
l = unsupported span of longitudinal/stiffener, in cm (in.), as shown in
5C-3-4/Figure 3
SM = net section modulus of longitudinal with the associated effective plating, in
cm3 (in3), at flange or point considered. The effective breadth, be, in cm (in.),
may be determined as shown in 5C-3-4/Figure 4.
Cy = 0.656(d/z)4 for side shell longitudinals only
where z/d ≥ 0.9, but Cy ≥ 0.30
= 1.0 elsewhere
z = distance above keel of side shell longitudinal under consideration
d = scantling draft, m (ft)
Ct = correction factor for the combined bending and torsional stress induced by
lateral loads at the welded connection of the flat bar stiffener or bracket to
the flange of longitudinal as shown in 5C-3-4/Figure 3.
= 1.0 + ar for unsymmetrical sections, fabricated or rolled
= 1.0 for tee and flat bars

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ar = CnCpSM/K

Cp = 31.2dw(e/l)2
e = horizontal distance between web centerline and the shear center of the cross
section, including longitudinal and the effective plating
= dwbf 2tf u/(2 SM) cm (in.)
K = St. Venant torsion constant for the longitudinal’s cross section, excluding the
associated plating.

= [bf t 3f + dw t w3 ]/3 cm4 (in4)

Cn = coefficient given in 5C-3-A1/Figure 3, as a function of ψ, for point (1)

shown in 5C-3-A2/Figure 1.
u = 1 − 2b1/bf

ψ = 0.31l(K/Γ)1/2
Γ = warping constant

= mIyf d w2 + d w3 t w3 /36 cm6 (in6)

Iyf = tf b 3f (1.0 + 3.0u2Aw/As)/12 cm4 (in4)

Aw = dwtw cm2 (in2)

As = net sectional area of the longitudinals, excluding the associated plating, in
cm2 (in2)
m = 1.0 − u(0.7 − 0.1dw /bf)
dw, tw, b1, bf, tf, all in cm (in.), are as defined in 5C-3-A2/Figure 1. For general applications, ar
needs not to be taken greater than 0.65 for a fabricated angle bar and 0.50 for a rolled section.
For connection as specified in 5C-3-A1/3.3.4, the wave-induced additional secondary stress f d*2
may be ignored.

7.11.2 Calculation of f d3
For welded joints of a stiffened plate panel, fd3 may be determined based on the wave-induced
local loads as specified in 5C-3-A1/7.11.1 above, using the approximate equations given below.
For direct calculation, non-linear effect and membrane stresses in the plate may be considered.
For plating subjected to lateral load, fd3 in the longitudinal direction is determined as:

fd3 = 0.182p(s/tn)2 N/cm2 (kgf/cm2, lbf/in2)

where
p = wave-induced local net pressure range, in N/cm2 (kgf/cm2, lbf/in2)
s = spacing of longitudinal stiffeners, in mm (in.)
tn = net thickness of plate, in mm (in.)

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Appendix 1 Guide for Fatigue Strength Assessment of Bulk Carriers 5C-3-A1

7.13 Calculation of Stress Range for Hold Frame

For the fatigue strength assessment, the stress range acting at the flange of a hold frame may be obtained
from the following equation:

fR = cf cwKs| f R*2 | N/cm2 (kgf/cm2, lbf/in2)

the value of f R*2 may be approximated by

f R*2 = Ct M/SM + F/A N/cm2 (kgf/cm2, lbf/in2)

where
M = psl2/12 N-cm (kgf-cm, lbf-in.), at the supported ends of the hold frame
F = 10(0.5 + 2lH /be)Bspb, N (kgf, lbf)
At the locations [1] in 5C-3-A1/Figure 4, the bending moment, M, given above, may be adjusted to the
location of the bracket toe, i.e., Mx in 5C-3-4/Figure 4, but not less than 65% of M. At locations [2] and [3]
in 5C-3-A1/Figure 4, the bending moment, M, given above, may be used without modification.
Ks = stress concentration factor
= 1.0 for location [1]
= 2.0 for locations [2] and [3] unless otherwise determined from FEM analysis based
on 5C-3-A1/13
p = total range of the net fluctuating local loads of hold frame, N/cm2 (kgf/cm2, lbf/in2),
for the specified load cases, (LC5 and LC6) and (LC7 and LC8). For hold frames in
ballast holds, the local loads are also to be investigated for the load cases (LC9 and
LC10). The local loads are to be taken as an average value of those calculated at the
lower and upper end of the span.
pb = total range of the net fluctuating loads of double bottom, N/cm2 (kgf/cm2, lbf/in2), for
the corresponding load cases as mentioned above. The local loads are to be taken at
B/4 off the centerline of the hull girder transverse section
s = spacing of hold frames, in cm (in.)
l = unsupported span of the hold frame, as shown in 5C-3-A1/Figure 4, in cm (in.)
lH = length of the cargo hold, in m (ft)
be = breadth of the double bottom structure, in m (ft).
For vessels having lower wing tanks with sloping tops, making an angle of about 45
degrees with horizontal, the breadth may be measured between the midpoints of the
sloping plating
B = breadth of the vessel, in m (ft), as defined in 3-1-1/5
SM = section modulus of the hold frame with the associated effective plating, at the flange
or point considered, cm3 (in3). The effective breadth, be, may be determined as shown
in 5C-3-4/Figure 4, in cm (in.). For the fatigue assessment at locations [2] and [3] in
5C-3-A1/Figure 4, SM is to be taken at the lower and upper supported ends of the
hold frame, respectively. Where the bracket is fitted with the face plate or flange
sniped at both ends, such face plate or flange is not to be included in the calculation
of the section modulus.
A = net sectional area of the frame and the associated plating (stn), in cm2 (in2)
cf, cw and Ct are as defined in 5C-3-A1/9.1.1 and 5C-3-A1/7.11.1 above.

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 1 Guide for Fatigue Strength Assessment of Bulk Carriers 5C-3-A1

TABLE 2
Coefficient k2b for Double Bottom Panels when ρb ≥ 1.0
Bulk Carriers with Bulk Carriers with
ρb Double Sides or Two Single Sides and no
Long. Bulkheads long. Bulkheads
1.0 0.57 0.69
1.2 0.61 0.82
1.4 0.62 0.91
1.6 0.63 0.96
1.8 0.63 0.99
2.0 0.63 1.01
2.2 0.63 1.03
2.5 & up 0.63 1.04

TABLE 3
Coefficient kb′ for Double Bottom Panels when ρb ≤ 1.0
Bulk Carriers with Bulk Carriers with
1/ρb Double Sides or Two Single Sides and no
Long. Bulkheads long. Bulkheads
1.0 0.57 0.69
1.2 0.70 0.79
1.4 0.80 0.86
1.6 0.86 0.90
1.8 0.89 0.92
2.0 0.91 0.93
2.2 & up 0.92 0.92

TABLE 4
Coefficient k3b for Double Bottom Panels
Distance of the longitudinal member in question
from the middle of panel’s width Number of equally spaced* long. girders in the panel
None 1 2 3 4 5 & up
0 1.0 1.15 0.9 1.05 0.98 1.0
0.1b 0.95 1.0 0.9 0.9 0.95
b/6 0.9
0.25b 0.75 0.75 0.75 0.75 0.75 0.75
0.45b 0.30 0.25 0.35 0.30 0.33 0.30
0.50b 0 0 0 0 0 0
* Notes:
1 Girders are considered to be equally spaced if adjacent spacings differ by less than 15%.
2 For locations other than those given in Column 1, k3b is to be obtained by linear interpolation.

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 1 Guide for Fatigue Strength Assessment of Bulk Carriers 5C-3-A1

FIGURE 2
Dimensions of Double Bottom, Double Side
Type I when one or more longitudinal girders are fitted in double-skin structures
Type II when no longitudinal girders are fitted in double-skin structure

TOP AND BOTTOM

CONNECTIONS

l1 b/2

S
T

I II
SL SL

ri ri

_ SL
SL _ = = = =

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Appendix 1 Guide for Fatigue Strength Assessment of Bulk Carriers 5C-3-A1

TABLE 5
Coefficient k2s for Double Side Panels when ρs ≥ 1.0
ρs k2s
1.0 0.31
1.2 0.39
1.4 0.41
1.6 0.43
1.8 0.44
2.0 0.45
2.2 & up 0.45

TABLE 6
Coefficient ks′ for Double Side Panels when γs ≤ 1.0
1/ρs ks′
1.0 0.31
1.2 0.34
1.4 0.35
1.6 0.39
1.8 0.40
2.0 0.40
2.2 & up 0.40

TABLE 7
Coefficient k3s for Double Side Panels
Distance of the longitudinal member under
consideration from the middle of panel’s width Number of side stringers
None 1 2 3 & up
0 1.0 1.15 0.9 1.0
0.1h 0.95 1.0 — 0.95
h/6 — — 0.9 —
0.25h 0.75 0.75 0.75 0.75
0.45h 0.30 0.25 0.35 0.30
0.50h 0 0 0 0
* Note: For locations other than those given is column 1, k3s is to be obtained by linear interpolation.

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 1 Guide for Fatigue Strength Assessment of Bulk Carriers 5C-3-A1

FIGURE 3
Cn = Cn (ψ)

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 1 Guide for Fatigue Strength Assessment of Bulk Carriers 5C-3-A1

FIGURE 4
Hold Frame

[3]

d/2 [3]
d/2

[1]
d
[1]
SHELL PLATING

SHELL PLATING
l

l
SPAN

SPAN
[1]
d
[1]

d/2 d/2

[2] [2]

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Appendix 1 Guide for Fatigue Strength Assessment of Bulk Carriers 5C-3-A1

9 Resulting Total Stress Ranges

9.1 Definitions (1996)

9.1.1
The total stress range, fR, is computed as the sum of the two stress ranges as follows:

fR = cf (fRG + fRL) N/cm2 (kgf/cm2, lbf/in2)

where
fRG = global dynamic stress range in N/cm2 (kgf/cm2, lbf/in2)

= |(fd1vi – fd1vj) + (fd1hi − fd1hj )|

fRL = local dynamic stress range in N/cm2 (kgf/cm2, lbf/in2)

= cw |(fd2i + f d*2i + fd3i) − (fd2j + f d*2 j + fd3j)|

cf = adjustment factor to reflect a mean wasted condition

= 0.95
cw = coefficient for the weighted effects of the two paired loading patterns
= 0.75
fd1vi, fd1vj = wave-induced component of the primary stresses produced by hull girder
vertical bending in, N/cm2 (kgf/cm2, lbf/in2), for load case i and j of the
selected pairs of combined load cases, respectively
fd1hi, fd1hj = wave-induced component of the primary stresses produced by hull girder
horizontal bending in, N/cm2 (kgf/cm2, lbf/in2), for load case i and j of the
selected pairs of combined load cases, respectively
fd2i, fd2j = wave-induced component of the secondary bending stresses produced by the
bending of cross-stiffened panels between transverse bulkheads, in N/cm2
(kgf/cm2, lbf/in2), for load case i and j of the selected pairs of combined load
cases, respectively
f d*2i , f d*2i = wave-induced component of the additional secondary stresses produced by
the local bending of the longitudinal stiffener between supporting structures
(e.g., transverse bulkheads and web frames), in N/cm2 (kgf/cm2, lbf/in2), for
load case i and j of the selected pairs of combined load cases, respectively
fd3i, fd3j = wave-induced component of the tertiary stresses produced by the local
bending of plate elements between the longitudinal stiffeners, in N/cm2
(kgf/cm2, lbf/in2), for load case i and j of the selected pairs of combined load
cases, respectively
For calculating the wave induced stresses, the sign convention is to be observed for the respective
directions of wave-induced loads as specified in 5C-3-3/Table 1. The wave-induced local loads are
to be calculated with the sign convention for the external and internal loads; however, the total of
the external and internal pressures, including both static and dynamic components, need not be
taken less than zero.
These wave-induced stresses are to be determined based on the net ship scantlings (see 5C-3-A1/1.7)
and in accordance with 5C-3-A1/7.5 through 5C-3-A1/7.11. The results of direct calculation where
carried out may also be considered.

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Appendix 1 Guide for Fatigue Strength Assessment of Bulk Carriers 5C-3-A1

11 Determination of Stress Concentration Factors (SCFs)

11.1 General (1995)

This section contains information on stress concentration factors (SCFs) to be considered in the fatigue
assessment.
Where, for a particular example shown, no specific value of SCF is given when one is called for, it indicates
that a finite element analysis is needed. When the fine mesh finite element approach is used, additional
information on calculations of stress concentration factors and the selection of compatible S-N data is
given in 5C-3-A1/13.

11.3 Sample Stress Concentration Factors (SCFs) (1 July 2001)

11.3.1 Cut-outs (Slots) for Longitudinals (1995)
SCFs, fatigue classifications and peak stress ranges may be determined in accordance with
5C-3-A1/Table 8 and 5C-3-A1/Figure 5.

TABLE 8
Ks (SCF) Values
Ks (SCF)
Configuration Unsymmetrical Flange Symmetrical Flange
Location [1] [2] [3] [1] [2] [3]
Single-sided Support 2.0 2.1 — 1.8 1.9 —
Single-sided Support with F.B. Stiffener 1.9 2.0 — 1.7 1.8 —
Double-sided Support 2.4 2.6 1.9 2.4 2.4 1.8
Double-sided Support with F.B. Stiffener 2.3 2.5 1.8 2.3 2.3 1.7

Notes: a The value of Ks is given based on nominal shear stresses near the locations under consideration.
b Fatigue classification
Locations [1] and [2]: Class C or B as indicated in 5C-3-A1/Table 1
Location [3]: Class F
c The peak stress range is to be obtained from the following equations:
1 For locations [1] and [2] (1999)
fRi = cf [Ksifsi + fni]
where
cf = 0.95
fsi = fsc + αi fswi, fsi ≥ fsc
αi = 1.8 for single-sided support
= 1.0 for double-sided support
fni = normal stress range in the web plate
fswi = shear stress range in the web plate
= Fi/Aw
Fi is the calculated web shear force range at the location considered. Aw is the area of web.
fsc = shear stress range in the support (lug or collar plate)
= CyP/(Ac + As)
Cy is as defined in 5C-3-A1/7.11.1.
P = slpo
po = fluctuating lateral pressure
Ac = sectional area of the support or of both supports for double-sided support
As = sectional area of the flat bar stiffener, if any
Ksi = SCFs given above

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Appendix 1 Guide for Fatigue Strength Assessment of Bulk Carriers 5C-3-A1

TABLE 8 (continued)
Ks (SCF) Values
s = spacing of longitudinal/stiffener
l = spacing of transverses

2 For location [3]

2
fR3 = cf [f n 3 + (Ks fs2)2]1/2
where
cf = 0.95
fn3 = normal stress range at location [3]
fs2 = shear stress range as defined in 1 above near location [3].
Ks = SCFs given above

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FIGURE 5
Cut-outs (Slots) For Longitudinal (1995)

Double - Sided Support

Web Plate
Class C or B F.B. Stiffener

[2] [2]
[1]
[1]
F1 F2 F1 F2
R R f3
f3
[1] [1]
[3] [3]
f s1 f s2 f s1 f s2

P R ≥ 35mm P

Web Plate
Class C or B F.B. Stiffener

[2] [2]
[1] [1]
F1 F2 F1 F2
R R R f3
f3
[1] [1] [3] [3]
f s1 f s2 f s2
f s1

R ≥ 35mm
P P

Single - Sided Support

Web Plate
Class C or B F.B. Stiffener

[2] [2] [1] [2]

F1 F2 F1 F2
R R R R
f3 f3
[1]
f s2 [3] f s1 f s1

R ≥ 35mm
P P

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Appendix 1 Guide for Fatigue Strength Assessment of Bulk Carriers 5C-3-A1

11.3.2 Flat Bar Stiffeners for Longitudinals (1999)

11.3.2(a) For assessing fatigue life of a flat bar stiffener at location [1] or [2] as shown in
5C-3-A1/Figure 6, the peak stress range is to be obtained from the following equations:
fRi = [(αi fs)2 + fL2 ]1/2 (i = 1 or 2)
where
fs = nominal stress range in the flat bar stiffener.
= cf CyP/(As + Ac)
P, As, Ac, cf are as defined in 5C-3-A1/11.3.1 and Cy in 5C-3-A1/7.11.1. For flat bar stiffener with
soft-toed brackets, the brackets may be included in the calculation of As.
fLi = stress range in the longitudinal at Location i (i = 1or 2), as specified in
5C-3-A1/9
αi = stress concentration factor at Location i (i = 1or 2) accounting for
misalignment and local distortion.
At location [1]
For flat bar stiffener without brackets
α1 = 1.50 for double-sided support connection
= 2.00 for single-sided support connection
For flat bar stiffener with brackets
α1 = 1.00 for double-sided support connection
= 1.25 for single-sided support connection
At location [2]
For flat bar stiffener without brackets
α2 = 1.25 for single or double-sided support connection
For flat bar stiffener with brackets
α2 = 1.00 for single or double-sided support connection
11.3.2(b) For assessing the fatigue life of the weld throat as shown in 5C-3-A1/Table 1, Class W,
the peak stress range fR at the weld may be obtained from the following equation:
fR = 1.25fsAs /Asw
where
Asw = sectional area of the weld throat. Brackets may be included in the calculation
of Asw.
fs and As are as defined in 5C-3-A1/11.3.2(a).
11.3.2(c) For assessing fatigue life of the longitudinal, the fatigue classification given in
5C-3-A1/Table 1 for a longitudinal as the only load carrying member is to be considered. Alternatively,
the fatigue classification shown in the 5C-3-A1/Figure 6 in conjunction with the combined stress
effects, fR, may be used. In calculation of fR, the αi may be taken as 1.25 for both locations [1] and [2].

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 1 Guide for Fatigue Strength Assessment of Bulk Carriers 5C-3-A1

FIGURE 6
Fatigue Classification for Longitudinals in way of Flat Bar Stiffener

45° 45°

* *

* may be used in the calculation

of As and Asw.

Web Plate
Web Plate

Flat Bar

Flat Bar
[1]
Class E
fL1 [1] [2]

fs
[2] Class E Class E
fs

[1] Class F
Class F

fL1 fL2 fL1 fL2

Longitudinal Longitudinal
Shell Plating Shell Plating

P P

F.B. without Brackets F.B. with Brackets

11.3.3 Welded Connection with Two or More Load Carrying Members

For brackets connecting two or more load carrying members, an appropriate stress concentration
factor (SCF) determined from fine mesh 3D or 2D finite element analysis is to be used. In this
connection, the fatigue class at bracket toes may be upgraded to class E. Sample connections are
illustrated below with SCF.
11.3.3(a) Connection of Longitudinal and Stiffener. Fatigue class designation and SCFs may be
determined as shown in 5C-3-A1/Figure 7.
11.3.3(b) Connection Between Corrugated Transverse Bulkhead and Deck. Fatigue class designation
and SCFs may be determined as shown in 5C-3-A1/Figure 8.
11.3.3(c) Connection Between Corrugated Transverse Bulkhead and Inner Bottom with Respect
to Lateral Load on the Bulkhead. Fatigue class designation and SCFs may be determined as shown
in 5C-3-A1/Figure 9.
11.3.3(d) Connection Between Inner Bottom and Hopper Tank Slope. Fatigue class designation
and SCFs may be determined as shown in 5C-3-A1/Figure 10.
11.3.3(e) Hatch Corner. Fatigue class designation and SCFs may be determined as shown in
5C-3-A1/Figure 11.
11.3.3(f) Hold Frames. Fatigue class designation and SCFs may be determined as shown in
5C-3-A1/Figure 12.
11.3.3(g) Doublers and Non-Load Carrying Members on Deck or Shell Plating. Fatigue class
designation and SCFs may be determined as shown in 5C-3-A1/Figure 13.

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FIGURE 7
Connection of Longitudinal and Stiffener

E with SCF E with SCF

FIGURE 8
Connection Between Corrugated Transverse Bulkhead and Deck

E with SCF

HATCH SIDE
COAMING
DETAIL

Deck

Corrugated Bhd

Deck

E with SCF

E with SCF

Deck

E with SCF

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FIGURE 9
Connection between Corrugated Transverse Bulkhead and Inner Bottom
with Respect to Lateral Load on the Bulkhead

E with SCF E with SCF

E with SCF

E with SCF E with SCF

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FIGURE 10
Connection between Inner Bottom and Hopper Tank Slope

E with SCF C with SCF

FIGURE 11
Hatch Corner

C with SCF

E with SCF

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FIGURE 12
Hold Frames

E with SCF

E with SCF E with SCF

E with SCF

F2

F2 F2
SHELL PLATING

F2

E with SCF

E with SCF

E with SCF E with SCF

F2
G
SHELL PLATING

SHELL PLATING

FRAME
FRAME

G F2

E with SCF E with SCF

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 1 Guide for Fatigue Strength Assessment of Bulk Carriers 5C-3-A1

FIGURE 13
Doublers and Non-load Carrying Members on Deck or Shell Plating

G
G
C E

D E F2

13 Stress Concentration Factors Determined From Finite Element

Analysis

13.1 Introduction (1995)

S-N data and stress concentration factors (SCFs) are related to each other and therefore should be
considered together so that there is a consistent basis for the fatigue assessment.
The following guidance is intended to help make correct decisions.

13.3 S-N Data (1995)

S-N data are presented as a series of straight-lines plotted on log-log scale. The data reflect the results of
numerous tests which often display considerable scatter. The recommended design curves for different
types of structural details and welded connections recognize the scatter in test results in that the design
curves have been based on the selection of the lower bound, 95% confidence limit. In other words, about
2.5% of the test failure results fall below this curve. Treating the design curve in this manner introduces a
high, yet reasonable degree of conservatism in the design and fatigue evaluation processes.
Individual S-N curves are presented to reflect certain generic structural geometries or arrangements.
5C-3-A1/Table 1 and 5C-3-A1/11.3 contain sketches of typically found weld connections and other details
in ship structure, giving a list of the S-N classification. This information is needed to assess the fatigue
strength of a detail. Also needed is a consistent way to establish the demands or load effects placed on the
detail so that a compatible assessment can be made of the available strength versus the demand. Here is
where interpretation and judgment enter the fatigue assessment.
S-N curves are obtained from laboratory sample testing. The applied reference stress on the sample which
is used to establish the S-N data is referred to as the nominal stress. The nominal stress is established in a
simple manner, such as force divided by area and bending moment divided by section modulus (P/A &
M/SM). The structural properties used to establish the nominal stress are taken from locations away from
any discontinuities to exclude local stress concentration effects arising from the presence of a weld or other
local discontinuity. In an actual structure, it is rare that a match will be found between the tested sample
geometry and loadings. One is then faced with the problem of making the appropriate interpretation.

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Appendix 1 Guide for Fatigue Strength Assessment of Bulk Carriers 5C-3-A1

13.5 S-N Data and SCFs (2003)

Selection of appropriate S-N data are straightforward with respect to “standard details” offered in
5C-3-A1/Table 1 or other similar reference. However, in the case of welded connections in complex
structures, it is required that SCFs be used to modify the nominal stress range. An example of the need to
modify nominal stress for fatigue assessment purposes is shown in 5C-3-A1/Figure 14 below, relating to a
hole drilled in the middle of a flat plate traversed by a butt weld.
In this example, the nominal stress SN is P/Area, but the stress to be used to assess the fatigue strength at
point A is SA or SN·SCF. This example is deceptively simple because it does not tell the entire story. The
deficiency of the example is that one needs to have a definitive and consistent basis to obtain the SCF.
There are reference books which indicate that based on the theory of elasticity, the SCF to be applied in
this case is 3.0. However, when the SCF is computed using the finite element analysis techniques, the SCF
obtained can be quite variable depending on the mesh size. The example does not indicate which S-N
curve should be applied, nor does the example show how the selection of the design S-N data could be
affected by the mentioned finite element analysis issues. Therefore, if such interpretation questions exist
for a simple example, the higher difficulty of appropriately treating more complex structures should be evident.
Referring to the S-N curves to be applied to welded connections (for example S-N curves D-W in
5C-3-A1/Figure 1), the SCFs resulting from the presence of the weld itself are already accounted for in
these curves. If one were to have the correct stress distribution in the region – from the weld to a location
sufficiently away from the weld toe (where the stress is suitably established by the nominal stress obtained
from P/A and M/SM – the stress distribution may be generically separated into three distinct segments as
shown in the 5C-3-A1/Figure 15 below.
• Region III is a segment where the stress gradient is controlled by the nominal stress gradient.
• Region II is a segment where the nominal stress gradient is being modified due to the presence of other
structure such as the bracket end shown in the figure. This must be accounted for to obtain an
appropriate stress to be used in the fatigue analysis at the weld toe.
• Region I is a segment where the stress gradient is being modified due to the presence of the weld metal
itself. The stress concentration due to the weld is already accounted for in the S-N design curve and
need not be discussed further. Since the typical way to determine the stress distribution is via planar/linear
elements which ignore the weld, this is consistent with the method of analysis.
This general description of the stress distribution is again inconclusive because one does not know in advance
and with certainty the distances from the weld toe where the indicated changes of slope for the stress
gradient occur. For this reason, definite rules need to be established to determine the slopes, then criteria
can be established and used to find the stress at the weld toe which is to be used in the fatigue assessment.
In this regard two approaches can be used to find the stress at the weld toe, which reflect two methods of
structural idealization. One of these arises from the use of a conventional beam element idealization of the
structure including the end bracket connection, and the other arises from the use of a fine mesh finite
element idealization.
Using a beam element idealization, the nominal stress at any location (i.e., P/A and M/SM) can be obtained.
(See 5C-3-4/Figure 4 for a sample beam element model).
In the beam element idealization, there will be questions as to whether or not the geometric stress concentration
due to the presence of other structure is adequately accounted for; this is the “Segment II” stress gradient
previously described. In the beam modeling approach shown in the figure, the influence on stresses arising
from the “carry over” of forces and bending moments from adjacent structural elements has been approximately
accounted for. At the same time, the strengthening effect of the brackets has been ignored. Hence, for
engineering purposes, this approach is considered to be sufficient in conjunction with the nominal stress
obtained at the location of interest and the nominal S-N curve, i.e., the F or F2 Class S-N data, as appropriate.
In the fine mesh finite element analysis, approach one needs to define the element size to be used. This is
an area of uncertainty because the calculated stress distribution can be unduly affected by both the
employed mesh size and the uniformity of the mesh adjacent to the weld toe. Therefore, it is necessary to
establish “rules” as given below to be followed in the producing of the fine mesh model adjacent to the
weld toe. Further, since the area adjacent to the weld toe (or other discontinuity of interest) may be
experiencing a large and rapid change of stress (i.e., a high stress gradient), it is also necessary to provide a
rule which can be used to establish the stress at the location where the fatigue assessment is to be made.

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Appendix 1 Guide for Fatigue Strength Assessment of Bulk Carriers 5C-3-A1

5C-3-A1/Figure 16 shows an acceptable method which can be used to extract and interpret the “near weld
toe” element stresses and to obtain a (linearly) extrapolated stress at the weld toe. When plate or shell
elements are used in the modeling, it is recommended that each element size is to be equal to the plate
thickness. When stresses are obtained in this manner the use of the E Class S-N data is considered to be
acceptable.
Weld hot spot stress can be determined from linear extrapolation of surface component stresses at t/2 and
3t/2 from weld toe. The principal stresses at hot spot are then calculated based on the extrapolated stresses
and used for fatigue evaluation. Description of the numerical procedure is given in 5C-3-A1/13.7 below.

FIGURE 14
(1995)
S N = P/Area

A
P
SA

SCF = SA / SN

FIGURE 15
(1995)
Calculated Stress

Physical Stress

I Bracket
II
III

Weld

Stiffener

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 1 Guide for Fatigue Strength Assessment of Bulk Carriers 5C-3-A1

FIGURE 16
(2003)
Peak Stress

Weld Toe "Hot Spot" Stress

t Weld Toe

~
~ t Weld Toe Location

t/2

3t/2

13.7 Calculation of Hot Spot Stress for Fatigue Analysis of Ship Structures (2003)
The algorithm described in the following is applicable in order to obtain the hot spot stress for the point at
the toe of a weld. The weld typically connects either a flat bar member or a bracket to the flange of a
longitudinal stiffener as shown in 5C-3-A1/Figure 17.
Consider the four points, P1 to P4, measured by the distances X1 to X4 from the weld toe, designated as the
origin of the coordinate system. These points are the centroids of four neighboring finite elements, the first
of which is adjacent to the weld toe. Assuming that the applicable surface component stresses, Si, at Pi
have been determined from FEM analysis, the corresponding stresses at “hot spot”, i.e., the stress at the
weld toe, can be determined by the following procedure:
13.7.1
Select two points, L and R, such that points L and R are situated at distances t/2 and 3t/2 from the
weld toe; i.e.,
XL = t/2, XR = 3t/2
where t denotes the thickness of the member to which elements 1 to 4 belong (e.g., the flange of a
longitudinal stiffener).
13.7.2
Let X = XL and compute the values of four coefficients as follows:
C1 = [(X – X2) (X – X3) (X – X4)] / [(X1 – X2) (X1 – X3) (X1 – X4)]
C2 = [(X – X1) (X – X3) (X – X4)] / [(X2 – X1) (X2 – X3) (X2 – X4)]
C3 = [(X – X1) (X – X2) (X – X4)] / [(X3 – X1) (X3 – X2) (X3 – X4)]
C4 = [(X – X1) (X – X2) (X – X3)] / [(X4 – X1) (X4 – X2) (X4 – X3)]
The corresponding stress at Point L can be obtained by interpolation as:
SL = C1S1 + C2S2 + C3S3 + C4S4

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13.7.3
Let X = XR and repeat Step in 5C-3-A1/13.7.2 to determine four new coefficients, the stress at
Point R can be interpolated likewise, i.e.,
SR = C1S1 + C2S2 + C3S3 + C4S4

13.7.4 (2003)
The corresponding stress at hot spot, S0, is given by

S0 = (3SL − SR)/2
Footnotes:
The algorithm presented in the foregoing involves two types of operations. The first is to utilize the stress values at the centroid
of the four elements considered to obtain estimates of stress at Points L and R by way of an interpolation algorithm known as
Lagrange interpolation. The second operation is to make use of the stress estimates SL and SR to obtain the hot spot stress via
linear extrapolation.
While the Lagrange interpolation is applicable to any order of polynomial, it is not advisable to go beyond the 3rd order
(cubic). Also, the even order polynomials are biased; so that leaves the choice between a linear scheme and a cubic scheme.
Therefore, the cubic interpolation as described in 5C-3-A1/13.7.2 should be used. It can be observed that the coefficients, C1
to C4 are all cubic polynomials. It is also evident that, when X = Xj which is not equal to Xi all the C‘s vanish except Ci; and
if X = Xi, Ci = 1.

FIGURE 17
(1995)
X
3t/2

t/2

(L) (R)

P1 P2 P3 P4
t

X1
X2
X3
X4

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PART Appendix 2: Calculation of Critical Buckling Stresses

5C
CHAPTER 3 Vessels Intended to Carry Ore or Bulk Cargoes
(150 meters (492 feet) or more in Length)

APPENDIX 2 Calculation of Critical Buckling Stresses

1 General
The critical buckling stresses for various structural elements and members may be determined in accordance
with this Appendix or other recognized design practices. Critical buckling stresses derived from experimental
data or analytical studies may be considered, provided well documented supporting data are submitted for
review.

3 Rectangular Plates (1995)

The critical buckling stresses for rectangular plate elements, such as plate panels between stiffeners; web
plates of longitudinals, girders, floors and transverses; flanges and face plates, may be obtained from the
following equations with respect to uniaxial compression, bending and edge shear, respectively.
fci = fEi for fEi ≤ Pr fyi

fci = fyi[1 − Pr(1 – Pr) fyi/fEi] for fEi > Pr fyi

where
fci = critical buckling stress with respect to uniaxial compression, bending or edge shear,
separately, N/cm2 (kgf/cm2, lbf/in2)
fEi = Ki[π2E/12(1 − ν2)](tn/s)2, N/cm2 (kgf/cm2, lbf/in2)
Ki = buckling coefficient as given in 5C-3-A2/Table 1
E = modulus of elasticity of the material, may be taken as 2.06 × 107 N/cm2
(2.1 × 106 kgf/cm2, 30 × 106 lbf/in2) for steel
ν = Poisson’s ratio, may be taken as 0.3 for steel
tn = net thickness of the plate, in cm (in.)
s = spacing of longitudinals/stiffeners, in cm (in.)
Pr = proportional linear elastic limit of the structure, may be taken as 0.6 for steel
fyi = fy, for uniaxial compression and bending

= fy / 3 , for edge shear

fy = specified minimum yield point of the material, in N/cm2 (kgf/cm2, lbf/in2)

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Appendix 2 Calculation of Critical Buckling Stresses 5C-3-A2

TABLE 1
Buckling Coefficient, Ki (1995)
For Critical Buckling Stress Corresponding to fL, fT, fb or fLT
I. Plate panel between stiffeners Ki
A Uniaxial compression l a. For f′L, = fL: 4C1,
fL fL
1. Long plate b. For f′L, = fL/3: 5.8C1,
l≥s S (see note)

f 'L f 'L

2. Wide plate fT a. For f′T, = fT: [1 + (s/l)2]2C2

f 'T
l≥s b. For f′T, = fT/3: 1.45[1 + (s/l)2]2C2
(see note)
S l

f 'T
fT

B Ideal Bending fb l fb
1. Long plate 24C1
s
l≥s
-fb -fb

2. Wide plate a. For 1.0 ≤ l/s ≤ 2.0: 24 (s/l)2C2

fb
l≥s b. For 2.0 < l/s : 12 (s/l)C2
-fb

s l

-fb

fb

C Edge Shear fLT Ki

[5.34 + 4 (s/l)2]C1
s fLT

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Appendix 2 Calculation of Critical Buckling Stresses 5C-3-A2

TABLE 1 (continued)
Buckling Coefficient, Ki (1995)
D Values of C1 and C2
1. For plate panels between angles or tee stiffeners
C1 = 1.1
C2 = 1.3 within the double bottom or double side*
C2 = 1.2 elsewhere
2. For plate panels between flat bars or bulb plates
C1 = 1.0
C2 = 1.2 within the double bottom or double side*
C2 = 1.1 elsewhere
* applicable where shorter edges of a panel are supported by rigid structural members, such as bottom, inner
bottom, side shell, inner skin bulkhead, double bottom floor/girder and double side web stringer.

II. Web of Longitudinal or Stiffener Ki

A Axial compression
Same as I.A.1 by replacing s with depth of the web and l with unsupported span
a. For f′L = fL : 4C
b. For f′L = fL /2:
5.2C
(see note)
where
C = 1.0 for angle or tee stiffeners
C = 0.33 for bulb plates
C = 0.11 for flat bars
B Ideal Bending
Same as I.B.1 by replacing s with depth of the web and l with unsupported span 24C

III. Flange and Face Plate Ki

Axial Compression 0.44

b2 b2

s = b2
l = unsupported span
Note:
In I.A. (II.A), Ki for intermediate values of f′L/fL (f′T/fT) may be obtained by interpolation between a and b.

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Appendix 2 Calculation of Critical Buckling Stresses 5C-3-A2

5 Longitudinals, Stiffeners, Hold Frames and Unit Corrugation for

Transverse Bulkhead

5.1 Axial Compression (2002)

The critical buckling stress, fca, of a beam-column, i.e., the longitudinal and the associated effective plating,
with respect to axial compression may be obtained from the following equations:
Fca = fE for fE ≤ Pr fy

fca = fy[1 − Pr(1 − Pr)fy /fE], for fE > Pr fy

where
fE = π2E/(l/r)2, N/cm2 (kgf/cm2, lbf/in2)
l = unsupported span of the longitudinal or stiffener, in cm (in.), as defined in
5C-3-4/Figure 3
r = radius of gyration of area Ae, in cm (in.)
Ae = As + bwLtn
As = net sectional area of the longitudinals or stiffeners excluding the associated plating,
cm2 (in2)
bwL = effective width of the plating, as given in 5C-3-5/5.3.2, in cm (in.)
tn = net thickness of the plating, in cm (in.)
fy = minimum specified yield point of the longitudinal or stiffener under consideration,
N/cm2 (kgf/cm2, lbf/in2)
Pr and E are as defined in 5C-3-A2/3.

5.3 Torsional/Flexural Buckling (2002)

The critical torsional/flexural buckling stress with respect to axial compression of a longitudinal, including
its associated plating (effective width, bwL) may be obtained from the following equations:

fct = fET for fET ≤ Pr fy

fct = fy[1 − Pr(1 − Pr)fy /fET] for fET ≥ Pr fy

where
fct = critical torsional/flexural buckling stress with respect to axial compression, N/cm2
(kgf/cm2, lbf/in2)
fET = E[K/2.6 + (nπ/l)2Γ + Co(l/nπ)2/E]/Io[1 + Co(l/nπ)2/Io fcL], N/cm2 (kgf/cm2, lbf/in2)
K = St. Venant torsion constant for the longitudinal’s cross section, excluding the
associated plating.

= 1/3[bf t 3f + dw t w3 ]

Io = polar moment of inertia of the longitudinal, excluding the associated plating, about
the toe (intersection of web and plating), in cm4 (in4)

= Ix + mIy + As( xo2 + y o2 )

Ix, Iy = moment of inertia of the longitudinal about the x-and y-axis, respectively, through the
centroid of the longitudinal, excluding the plating (x-axis perpendicular to the web),
in cm4 (in4)
m = 1.0 − u(0.7 − 0.1 dw /bf)

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Appendix 2 Calculation of Critical Buckling Stresses 5C-3-A2

u = unsymmetry factor
= 1 − 2b1 /bf
xo = horizontal distance between centroid of stiffener As and centerline of the web plate,
cm (in.)
yo = vertical distance between the centroid of the longitudinal’s cross section and its toe,
cm (in.)
dw = depth of the web, cm (in.)
tw = net thickness of the web, cm (in.)
bf = total width of the flange/face plate, cm (in.)
b1 = smaller outstanding dimension of flange with respect to centerline of web (see
5C-3-A2/Figure 1), cm (in.)
tf = net thickness of the flange/face plate, cm (in.)

Co = E t n3 /3s

Γ = warping constant

≅ mIyf d w2 + d w3 t w3 /36

Iyf = tf b 3f (1.0 + 3.0u2dwtw /bf tf)/12, cm4 (in4)

fcL = critical buckling stress for the associated plating corresponding to n half-waves,
N/cm2 (kgf/cm2, lbf/in2)
= π2E(n/α +α/n)2(tn/s)2/12(1 − ν2)
α = l/s
n = number of half-wave which yield a smallest fET
= 1 for fixed end beam
fy = minimum specified yield point of the longitudinal or stiffener under consideration,
N/cm2 (kgf/cm2, lbf/in2)
Pr, E, s and v are as defined in 5C-3-A2/3.
As, tn and l are as defined in 5C-3-A2/5.1.

5.5 Buckling Criteria for Unit Corrugation of Transverse Bulkhead

The critical buckling stress, which is also the ultimate bending stress, fcb, for a unit corrugation may be
determined from the following equation (See 5C-3-5/5.11.2):
fcb = fEc for fEc ≤ Pr fy
fcb = [1 − Pr(1 − Pr)fy /fEc]fy for fEc > Pr fy
where
fEc = kcE(t/a)2
kc = 0.091 [7.65 − 0.26(c/a)2]2
c and a are widths of the web and flange panels, respectively, in cm2 (in2)
t = net thickness of the flange panel, in cm (in.)
Pr, fy and E are as defined in 5C-3-A2/3.
The maximum vertical bending moment, M, may be determined in accordance with 5C-3-4/25 at the lower
end of the corrugation.

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Appendix 2 Calculation of Critical Buckling Stresses 5C-3-A2

FIGURE 1
Net Dimensions and Properties of Stiffeners (1995)
bf

b2 b1
1

tf

xo
CENTROID OF WEB
AND FACE PLATE
(NET SECTION)

tw

yo
dw

tp

be

1 = point considered for

coefficient, Cn given
in 5C-3-A1/Figure 3

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Appendix 2 Calculation of Critical Buckling Stresses 5C-3-A2

7 Stiffened Panels (1996)

7.1 Large Stiffened Panels

For large stiffened panels between bulkheads or panels stiffened in one direction between transverses and
girders, the critical buckling stresses with respect to uniaxial compression may be determined from the
following equations:
fci = fEi for fEi ≤ Pr fy
fci = fy[1 − Pr(1− Pr)fy /fEi] for fEi > Pr fy
where
fEi = kLπ2(DLDT)1/2/tL b2 in the longitudinal direction, N/cm2 (kgf/cm2, lbf/in2)

fEi = kTπ2(DLDT)1/2/tTl2 in the transverse direction, N/ cm2 (kgf/cm2, lbf/in2)

kL = 4 for l/b ≥ 1

= [1/φ 2L + 2η + φ 2L ] for l/b < 1

kT = 4 for b/l > 1

= [1/φ T2 + 2η + φ T2 ] for b/l < 1

DL = EIL/sL(1 − ν2)

DL = E t n3 /12(1 − ν2) if no stiffener in the longitudinal direction

DT = EIT /sT(1 − ν2)

DT = E t n3 /12(1 − ν2) if no stiffener in the transverse direction

l, b = length and width between transverse and longitudinal bulkheads, respectively, cm

(in.) (See 5C-3-A2/Figure 2.)
tL, tT = net equivalent thickness of the plating and stiffener in the longitudinal and transverse
direction, respectively, cm (in.)
= (sLtn + AsL)/sL or (sT tn + AsT)/sT
sL, sT = spacing of longitudinals and transverses, respectively, cm (in.) (See 5C-3-A2/Figure 2.)

φL = (l/b)(DT/DL)1/4

φT = (b/l)(DL/DT)1/4

η = [(IpLIpT)/(ILIT)]1/2
AsL, AsT = net sectional area of the longitudinal and transverse, excluding the associated plating,
respectively, cm2 (in2)
IpL, IpT = net moment of inertia of the effective plating (effective breadth due to shear lag)
alone about the neutral axis of the combined cross section, including stiffener and
plating, cm4 (in4)
IL, IT = net moment of inertia of the stiffener (one) with effective plating in the longitudinal
or transverse direction, respectively, cm4 (in4). If no stiffener, the moment of inertia is
calculated for the plating only.
fy, Pr, E and ν are as defined in 5C-3-A2/3. tn is as defined in 5C-3-A2/5.1.

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Appendix 2 Calculation of Critical Buckling Stresses 5C-3-A2

Except for deck panels, when the lateral load parameter, qo, defined below is greater than 5, reduction of
the critical buckling stresses given above is to be considered.
qo = pnb4/(π4tTDT)

qo = pnl4/(π4tLDL)
where
pn = average net lateral pressure N/cm2 (kgf/cm2, lbf/in2)

DT , b, l, tT and sT are as defined above.

In this regard, the critical buckling stress may be approximated by:
f ci′ = Ro fci N/cm2 (kgf/cm2, lbf/in2)
where
Ro = 1 − 0.045(qo − 5) for qo ≥ 5
Ro is not to be taken less than 0.5.

For deck panels, Ro = 1.0 and f ci′ = fci

FIGURE 2
l
T.B./S.S

sT

pn
longitudinal
b sL

L.B.

T.B. transverse plating, tn T.B.

7.3 Corrugated Transverse Bulkheads

For corrugated transverse bulkheads, the critical buckling stresses with respect to uniaxial compression
may be calculated from the equations given in 5C-3-A2/7.1 above by replacing the subscripts “L” and “T”
with “V” and “H” for the vertical and horizontal directions, respectively, and with the following
modifications. The rigidities DV and DH are defined as follows:
DV = EIv /s
DH = [s/(a+c)][Et3/12(1 − ν2)]

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Appendix 2 Calculation of Critical Buckling Stresses 5C-3-A2

where
Iv = moment of inertia of a unit corrugation with spacing s, s = a + c cos φ

= t/4[c sin φ]2 (a + c/4 + c sin φ/12), in cm4 (in4)

a, c = widths of the flange and web panels, respectively, in cm (in.)
t = net thickness of the corrugations, in cm (in.)
E and ν are as defined in 5C-3-A2/3.
l = length of the corrugation, in cm (in.)
sv, sH = s

η, IpH, AsH = 0
AsV = t c sin φ

φ is as defined in 5C-3-4/Figure 11.

9 Deep Girders, Webs and Stiffened Brackets

9.1 Critical Buckling Stresses of Web Plates and Large Brackets (1995)
The critical buckling stresses of web plates and large brackets between stiffeners may be obtained from the
equations given in 5C-3-A2/3 for uniaxial compression, bending and edge shear.

9.3 Effects of Cut-outs (1995)

The depth of cut-out, in general, is to be not greater than dw/3 and the stresses in the area calculated are to
account for the local increase due to the cut-out.
When cut-outs are present in the web plate, the effects of the cut-outs on reduction of the critical buckling
stresses is to be considered, as outlined below:
9.3.1 Reinforced by Stiffeners Around Boundaries of Cut-outs
When reinforcement is made by installing straight stiffeners along boundaries of the cut-outs, the
critical buckling stresses of web plate between stiffeners with respect to compression and shear
may be obtained from equations given in 5C-3-A2/3
9.3.2 Reinforced by Face Plates Around Contour of Cut-outs
When reinforcement is made by adding face plates along contour of the cut-out, the critical
buckling stresses with respect to compression, bending and shear may be obtained from equations
given in 5C-3-A2/3, without reduction, provided that the net sectional area of the face plate is not
less than 8 t w2 , where tw is the net thickness of the web plate and that depth of cut-out is not greater
than dw /3, where dw is the depth of the web.
9.9.3 No Reinforcement Provided
When reinforcement is not provided, the buckling strength of the web plate surrounding the cut-
out may be treated as a strip of plate with one edge free and the other edge simply supported.

9.5 Tripping (1995)

To prevent tripping of deep girders and webs with wide flanges, tripping brackets are to be installed with a
spacing generally not greater than 3 meters (9.84 ft). Design of tripping brackets may be based on the force
P acting on the flange, as given by the following equation:
⎛ 1 ⎞
P = 0.02 f cl ⎜ A f + Aw ⎟
⎝ 3 ⎠

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Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 2 Calculation of Critical Buckling Stresses 5C-3-A2

Af
P

1/3 Aw TRIPPING BRACKET

where
fcl = critical lateral buckling stress with respect to axial compression between tripping
brackets, N/cm2 (kgf/cm2, lbf/in2)
fcl = fce, for fce ≤ Pr fy
= fy[1 – Pr(1 − Pr) fy/fce], for fce > Pr fy
fce = 0.6E[(bf/tf )(tw/dw )3], N/cm2 (kgf/cm2, lbf/in2)
Af = net cross sectional area of the flange/face plate, in cm2 (in2)
Aw = net cross sectional area of the web, in cm2 (in2)
bf, tf, dw, tw are as defined in 5C-3-A2/5.3.
E, Pr and fy are as defined in 5C-3-A2/3.

11 Stiffness and Proportions

To fully develop the intended buckling strength of the assemblies of structural members and panels, supporting
elements of plate panels and longitudinals are to satisfy the following requirements for stiffness and proportion
in highly stressed regions.

11.1 Stiffness of Longitudinals (1995)

The net moment of inertia of the longitudinals, io, with effective breadth of net plating is to be not less than
that given by the following equation:

st n3
io = γo cm4 (in4)
12(1 − ν 2 )
where
γo = (2.6 + 4.0δ)α2 + 12.4α − 13.2α1/2
δ = A/stn
α = l/s
s = spacing of longitudinals, cm (in.)
tn = net thickness of plating supported by the longitudinal, cm (in.)
ν = Poisson’s ratio
= 0.3 for steel
A = net sectional area of the longitudinal (excluding plating), cm2 (in2)
l = unsupported span of the longitudinal, cm (in.)

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 519
Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 2 Calculation of Critical Buckling Stresses 5C-3-A2

11.3 Stiffness of Web Stiffeners (1995)

The net moment of inertia i of the web stiffener, with the effective breadth of net plating, not exceeding s
or 0.33l, whichever is less, is not to be less than obtained from the following equations:
i = 0.17lt3(l/s)3 cm4 (in4), for l/s ≤ 2.0
3 2 4 4
i = 0.34lt (l/s) cm (in ), for l/s > 2.0
where
l = length of stiffener between effective supports, in cm (in.)
t = required net thickness of web plating, in cm (in.)
s = spacing of stiffeners, in cm (in.)

11.5 Stiffness of Supporting Members (1995)

The net moment of inertia of the supporting members such as transverses and webs is not to be less than
that obtained from the following equation:
Is /io ≥ 0.2(Bs /l)3(Bs /s)
where
Is = moment of inertia of the supporting member, including the effective plating, cm4 (in4)
io = moment of inertia of the longitudinals, including the effective plating, cm4 (in4)
Bs = unsupported span of the supporting member, cm (in.)
l and s are as defined in 5C-3-A2/11.1.

11.7 Proportions of Flanges and Face Plates (1995)

The breadth-thickness ratio of flanges and face plates of longitudinals and girders is to satisfy the limits
given below.
b2/tf = 0.4(E/fy)1/2
where
b2 = larger outstanding dimension of flange, as given in 5C-3-A2/Figure 1, cm (in.)
tf = net thickness of flange/face plate, cm (in.)
E and fy are as defined in 5C-3-A2/3.

11.9 Webs of Longitudinals and Stiffeners

Depth-thickness ratio of webs of longitudinals and stiffeners is to satisfy the limits given below:
dw/tw ≤ 1.5(E/fy)1/2 for angles and tee bars

dw/tw ≤ 0.85(E/fy)1/2 for bulb plates

dw/tw ≤ 0.5(E/fy)1/2 for flat bars

where dw and tw are as defined in 5C-3-A2/5.3 and E and fy are as defined in 5C-3-A2/3
When these limits are complied with, the assumption on buckling control stated in 5C-3-5/5.1.2(e) is
considered satisfied. If not, the buckling strength of the web is to be further investigated as per 5C-3-A2/3
of this Appendix.

520 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
PART Appendix 3: The Design and Evaluation of Ore and Ore/Oil Carriers

5C
CHAPTER 3 Vessels Intended to Carry Ore or Bulk Cargoes
(150 meters (492 feet) or more in Length)

APPENDIX 3 The Design and Evaluation of Ore and Ore/Oil

Carriers

1 General
This Appendix is intended to provide guidance for the design and evaluation of ore and ore/oil carriers,
ranging in length from 150 to 350 meters, fitted with two complete longitudinal bulkheads which divide
the cross section into three holds of approximately equal breadth. The vessels may have a complete or
partial double bottom with a single bottom in the wing spaces and the double bottom space may be
designated for ballast, fuel oil or as voids. The ore cargo is to be carried only in the center holds with the
wing spaces used for ballast or cargo oil. The center holds may also be used for cargo or ballast. The
vessels are assumed to have large openings in the decks for hatchways.
The design criteria specified in Part 5C, Chapter 3 are generally applicable to this type of vessel with
modifications and additions as given in this appendix. The strength criteria as specified in Part 5C, Chapter 1,
and Part 5C, Chapter 2 may be applied to the same type of vessel for carriage of oil cargoes.

3 Nominal Design Corrosion Values

The nominal design corrosion values for an ore carrier may be taken the same as for a single hull tanker in
the wing tanks and as for a bulk carrier in the center hold. In ore/oil carriers where the wing spaces
alternate between ballast and cargo usage, the corrosion values for longitudinal scantlings are to be those
specified for ballast spaces while the nominal design corrosion values for transverse members may
correspond to the actual usage of the tank. Where two corrosion values are specified for one structural
item, as is the case for the longitudinal bulkheads, the larger value is to be adopted. The nominal design
corrosion value for double bottom voids may be 1.00 mm for transverse members.

5 Loading Patterns
Ten loading patterns given in 5C-3-A3/Figure 1 are to be used for determining local loads and calculating
structural responses for design and evaluation. These are applicable in conjunction with the ten combined
load cases specified in 5C-3-3/Table 1.

7 Strength Criteria
In general, initial scantlings for wing tank plating, stiffeners and main supporting structures may be determined
based on the requirements specified in Part 5C, Chapter 1 and Part 5C, Chapter 2. In way of the center ore holds,
the applicable portions of Section 5C-3-4 may be used. Certain structural members, which may be alternately
subject to dry and liquid cargo loading, such as the inner bottom and longitudinal and transverse bulkheads,
are to be checked against both the Tanker and Bulk Carrier Rules to determine the proper initial scantling.
Alternatively, the distribution of bending and shear in the main supporting structure for the determination
of initial scantlings may be obtained from a structural analysis with the loads specified in 5C-3-A3/5 above.
The required thickness of the longitudinal bulkheads for hull girder shear is to be determined in accordance
with 5C-1-4/5 with the distribution factors Ds and Di determined by direct calculation or by Appendix 5C-2-A1.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 521
 522
Part

LOAD CASE 1 LOAD CASE 2 LOAD CASE 3 LOAD CASE 4 LOAD CASE 5
Heading 0 Deg. Heading 0 Deg. Heading 0 Deg. Heading 0 Deg. Heading 90 Deg.
5C Specific Vessel Types

Heave Down Heave Up Heave Down Heave Up Heave Down

Pitch Bow Down Pitch Bow Up Pitch Bow Down Pitch Bow Up Pitch -
Roll - Roll - Roll - Roll - Roll STBD Down
Draft 2/3 Draft Full Draft 2/3 Draft Full Draft 2/3
Wave VBM Sag Wave VBM Hog Wave VBM Sag Wave VBM Hog Wave VBM Sag
Cargo S.G. 1.80 Cargo S.G. 1.80 Cargo S.G. 1.80 Cargo S.G. 1.80 Cargo S.G. 3.00
Ballast S.G. 1.025 Ballast S.G. 1.025 Ballast S.G. 1.025 Ballast S.G. 1.025 Ballast S.G. 1.025
FIGURE 1
Appendix 3 The Design and Evaluation of Ore and Ore/Oil Carriers

LOAD CASE 6 LOAD CASE 7 LOAD CASE 8 LOAD CASE 9 LOAD CASE 10
Loading Pattern of Ore/Oil Carrier

Heading 90 Deg. Heading 60 Deg. Heading 60 Deg. Heading 60 Deg. Heading 60 Deg.
Heave Up Heave Down Heave Up Heave Down Heave Up
Pitch Pitch Bow Down Pitch Bow Up Pitch Bow Down Pitch Bow Up
Roll STBD Up Roll STBD down Roll STBD Up Roll STBD Down Roll STBD Up
Draft Full Draft 2/3 Draft Full Draft 2/3 Draft 2/3
Wave VBM Hog Wave VBM Sag Wave VBM Hog Wave VBM Sag Wave VBM Hog
Cargo S.G. 3.00 Cargo Min S.G.* 1.05/1.80 Cargo S.G. 1.80 Cargo S.G. Cargo S.G.
Ballast S.G. 1.025 Ballast S.G. 1.025 Ballast S.G. 1.025 Ballast S.G. 1.025 Ballast S.G. 1.025
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)

Ballast, Specific Gravity 1.025 Cargo, Min. Specific Gravity* 1.05/1.80 Cargo, Min. Specific Gravity 3.00

*All vessels to be checked for specific gravity 1.05. Specific gravity 7.80 to be checked as special load case on ship by ship basis.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

5C-3-A3
Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 3 The Design and Evaluation of Ore and Ore/Oil Carriers 5C-3-A3

9 Cargo Loading (1 July 2010)

9.1 General
Ore Carriers and Ore or Oil Carriers, as defined in 5C-3-1/1.5.2 and 5C-3-1/1.5.3, are to be specifically
designed to be tolerant of more onerous loading processes, including the capability of loading cargo with a
single pour in each hold. The typical loading/unloading sequence stages shall be developed paying due
attention to the loading/unloading rate, the ballasting/deballasting capacity and the applicable strength
limitations.
This Subsection defines the mandatory design parameters for such loading and provides the evaluation
procedure and technical requirements for these vessels.
9.1.1 Documentation
The designer/shipbuilder is to prepare and submit for approval typical loading and unloading
sequence stages. This includes the synchronizing deballasting and ore loading. The requirements
in 5C-3-A3 especially noting 3-2-A3/5.1.2 and the Annex thereto are to be utilized.
The approved loading manual is to include the following:
• Approved typical loading/unloading sequence stages.
• Cargo Loading Rate in MT/hour, which is the maximum cargo loading rate used in
calculations described in Subsections 9.5 and 9.13.
• Cargo Overshooting in Minutes, which is the maximum cargo overshooting time used in
calculations described in Subsections 9.5 and 9.13.
A copy of the approved loading manual is to be placed onboard the vessel.

9.3 Evaluation Procedure

Compliance with the following is to be documented and demonstrated:
• Description of the target loading processes that are considered onerous for homogeneous, alternate or
other load conditions involving heavy density cargoes.
• Compliance with the allowable still water bending moment and shear force envelope curves through
the longitudinal strength calculations simulating each loading stage which includes load pouring,
loader shifting, de-ballasting and consumable loading.
• Compliance with the cargo mass curves as a function of draft through the hydrostatic calculations
simulating each loading stage which includes load pouring, loader shifting, de-ballasting and consumable
loading.
• Compliance with the FE-based strength criteria in the Steel Vessel Rules with explicit consideration of
cargo overshooting.

9.5 Target Loading Processes

Target loading processes consist of the initial ballast conditions, basic loading parameters and loading
sequences that are considered onerous to the hull structure. Target loading processes are to be defined for
alternate, block and homogeneous load conditions as applicable, involving heavy density cargoes. The
documentation of each target loading process is to be guided by 3-2-A3/5.1.2.
The ballast condition at the beginning of a loading process may have adverse effects on the hull structure.
The ballast condition (arrival) from the Loading Manual is to be used in strength evaluations. In addition,
ballast conditions (arrival at terminal) carrying the minimum ballast water, which are used to reduce de-
ballasting time, shall be considered for strength evaluations. The details of such conditions are typically
defined by air draft limitation, propeller immersion requirement, longitudinal strength considerations and
stability requirements.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 523
Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 3 The Design and Evaluation of Ore and Ore/Oil Carriers 5C-3-A3

Each target loading process is to be documented with the following parameters as applicable:
• The hull structure is to be capable of one loading pour per cargo hold
• The design is to be capable of handling ore loading sequences for the one pour per cargo hold. The
design is also to be checked for multi-pour loading per cargo hold if multi-pour loading is to be used
• Ore loading rate
• Loader shifting time between the hold loading pours. In absence of any available data, the hull structure
is to be evaluated assuming that the loader shifting time over a distance of less than or equal to four
hatch holds is five (5) minutes and the loader shifting time over a distance of more than four hatch
openings is ten (10) minutes. The loading process will stop during the transition of the loader while de-
ballasting will continue.
• The requirements in Appendix 5C-3-A3 are applicable to vessels that are engaged in loading with a
single loader. If simultaneous loading with two or more loaders is to be used, this is to be documented
and will be the subject of special consideration.
• De-ballasting sequences.
• The de-ballasting pump capacity. The hull structure is to be evaluated assuming that 80% of the
de-ballasting pump capacity is attainable during de-ballasting.
• Consumable loading sequences.
• The average overshooting time for individual loading pours, excluding the last trim pours. The hull
structure is to be evaluated assuming that additional cargo intake occurs due to overshooting for an
individual cargo hold. Overshooting in other cargo holds is not assumed.

9.7 Compliance with Allowable Still-Water Loading Limits

For each target loading process, the resulting calculated still-water shear forces and bending moments
along the vessel length are to be within the allowable still-water limits after the completion of each event
sequence stage such as loading pour, de-ballasting of ballast tank, loader shifting and consumable loading.
Compliance with the allowable still-water bending moment and shear force limits is to be verified for each
target loading process with and without overshooting.
Prior to the completion of the target loading process, compliance is to be verified with the allowable
in-port limits. The final loaded condition is to satisfy the allowable at sea limits.

9.9 Compliance with Allowable Mass Curves

For each target loading process, the mass of the contents in each cargo hold and double bottom space is to
be within the allowable mass versus draft curves after the completion of each loading sequence stage such
as loading pour, de-ballasting of ballast tank, loader shifting and consumable loading.
Compliance with the allowable mass versus draft curves is to be verified for each target loading process
without overshooting.
Prior to the completion of the target loading process, compliance is to be verified with the allowable mass
versus draft curves in port. The final loaded condition is to satisfy the allowable curves at sea.

9.11 Intermediate Calculations

The documentation requirements of the previous paragraphs of this section cover the results for the start
and end of each loading sequence stage. Whenever the loading/unloading equipment moves to the next
location, it constitutes the end of that stage. Intermediate calculations confirming that the allowable values
of the still-water bending moment and shear forces and the mass curves are not exceeded during the pour
itself or during the movement of the loader while ballast operations may be continuing are to be performed
and submitted for review. Typical loading rates for ore terminals are about 9,000~10,000 MT/hour. As a
minimum, intermediate strength checks are to be carried out at the time interval of “10,000 MT of
loading”, typically at about a 1 hour interval. If the loading rate is 20,000 MT/hour, the strength check is to
be checked at half hour intervals. The intermediate calculations are not required to be included in the
loading manual or placed onboard.

524 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 3 The Design and Evaluation of Ore and Ore/Oil Carriers 5C-3-A3

9.13 Total Strength Assessment against Cargo Overshooting

The hull structure loaded with extra cargo intake due to overshooting is to be evaluated using the global
finite element models for heavy or empty holds, as applicable. The applicable load cases are those with
heavy density cargo mass.
The following cargo mass definitions are used in this Section:
MHD = maximum cargo mass allowed to be carried in a cargo hold according to design
loading condition(s) with specified holds empty, if applicable, at maximum draft, in
MT
ΔM = overshoot cargo mass, in MT
= loading rate × average overshooting time

9.15 Vessels Carrying Ore Cargoes with SH Notation

The global hull structure is to be verified using Load Case 5 and 6 in 5C-3-A3/Figure 1 with the following
modifications. For these load cases where the holds are originally loaded with MHD, the new cargo mass
MHD + ΔM is to be applied.
The engineering procedures and analysis criteria in Sections 5C-3-3 and 5C-3-5 (except 5C-3-5/5.13) are
to be compiled with.

9.17 Ballast System

The ballast system is to be in accordance with 4-6-4/7. The basic principle of providing a reliable means
of pumping and draining per 4-6-4/7.1.2 is to be demonstrated. Ballast pumps are to be certified in
accordance with 4-6-1/7.3.

9.19 Automatic Draft Reading Sensors and Automatic Level-Gauging System

Consideration may also be given to providing automatic draft reading sensors and automatic level-gauging
systems. Where provided, functional descriptions and system diagrams are to be submitted for approval
for the automatic draft reading sensors and automatic level-gauging system for all ballast tanks linked to
the onboard loading computer, showing compliance with the following subsections. The interface of the
draft reading sensors and level-gauging system with the loading computer is to be demonstrated to the
attending Surveyor’s satisfaction.
9.19.1 Electrical and Mechanical Components
Electrical and mechanical components and their installation are to comply with Part 4, as applicable.
9.19.2 Electrical Installations in Hazardous Areas
Electrical installations in hazardous areas are to comply with 4-8-4/27.
9.19.3 Power Supply
Power supply is to be from the vessel's main power system. Consideration is to be given to the
possible results of loss of power. An uninterruptible power system (UPS) or supply from the
vessel’s emergency power system is to be provided, if considered necessary.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 525
PART Appendix 4: Load Cases for Structural Analysis with Respect to Slamming

5C
CHAPTER 3 Vessels Intended to Carry Ore or Bulk Cargoes
(150 meters (492 feet) or more in Length)

APPENDIX 4 Load Cases for Structural Analysis with Respect

to Slamming

1 Bowflare Slamming

1.1 Load Case – A

First cargo hold filled; second cargo hold empty; ballast tanks in both holds and fore peak ballast tank
empty (see 5C-3-A4/Figure 1).

1.3 Load Case – B

First cargo hold and ballast tanks in both holds empty; second cargo hold filled; fore peak ballast tank
filled (see 5C-3-A4/Figure 1).

1.5 Hull Girder Loads

Additional inertial load may be applied in conjunction with other local loads to yield the specified total
hull girder vertical shear force (VSF) at the aft transverse bulkhead of the first cargo hold of the fore-end
structural model.
Static VSF* kc = ±0.5

Dynamic VSF kc = ±1.0

* Maximum allowable still water VSF at aft transverse bulkhead section.

1.7 External Pressures

(including Pij as specified in 5C-3-3/11.3.1 and 5C-3-3/11.3.2, and 5C-3-3/5.5.4(a) for load case A, and
5C-3-3/11.3.1 and 5C-3-3/11.3.2, for load case B).
Kc = +1.0

Kfo = −1.0 sagging wave

1.9 Internal Bulk and Ballast Pressures

Kc = + 0.5 for bulk and ballast
Wv = + 0.6

Wl = Forward bulkhead + 0.6, Aft bulkhead −0.6

Pitch = −0.5
Roll = 0.0

526 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 4 Load Cases for Structural Analysis with Respect to Slamming 5C-3-A4

FIGURE 1
Loading Patterns for Slamming Study

load case C

Draft 1/2
ballast

S.G. 1.025
ballast
load case B
full load

Draft 2/3
S.G. 3.0
cargo
load case A
full load

Draft 2/3

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 527
Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 4 Load Cases for Structural Analysis with Respect to Slamming 5C-3-A4

1.11 Reference Wave Heading and Position

Heading Angle = 0 (head wave)
Heave = Down
Pitch = Bow down
Roll = 0

3 Bottom Slamming

3.1 Load Case – C

First cargo hold empty; second cargo hold empty; ballast tanks in both holds filled; fore peak ballast tank
filled (see 5C-3-A4/Figure 1).

3.3 Hull Girder Loads

Additional inertial load may be applied in conjunction with other local loads to yield the specified total
hull girder vertical bending moment (VBM) at the aft transverse bulkhead of the first cargo hold of the
fore-end structural model.
Static VBM* kc = +0.5
Dynamic VBM kc = +0.3
* Maximum allowable still water VBM at aft transverse bulkhead section.

3.5 External Pressures

(including Psi as specified in 5C-3-3/11.1.1 and 5C-3-3/11.1.3).
Kc = +1.0
kfo = +1.0 hogging wave

3.7 Internal Ballast Pressures (no bulk pressure)

Kc = +1.0 for ballast

Wv = −0.4

Wl = Forward bulkhead −0.2, Aft bulkhead +0.2

Pitch = +0.5
Roll = 0.0

3.9 Reference Wave Heading and Position

Heading angle = 0 (head wave)
Heave = Up
Pitch = Bow up
Roll = 0

528 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
PART Appendix 5a: Longitudinal Strength of Bulk Carriers in Flooded Condition

5C
CHAPTER 3 Vessels Intended to Carry Ore or Bulk Cargoes
(150 meters (492 feet) or more in Length)

APPENDIX 5a Longitudinal Strength of Bulk Carriers in Flooded

Condition (1 July 2003)

1 General

1.1 Application (1 July 2006)

This Appendix is to be complied with in respect to the flooding of any floodable cargo hold (see 5C-3-A5a/3.1)
of bulk carriers with the notation BC-A or BC-B, as defined in Appendix 5C-3-A6, that are constructed on
or after 1 July 2006.

1.3 Loading Conditions

Such vessels are to have their hull girder strength checked for specified flooded conditions, in each of the
cargo and ballast loading conditions defined in 3-2-1/3.3 and in every other condition considered in the
intact longitudinal strength calculations, including those in 3-2-A3/Table 1 and 3-2-A3/Table 2, except that
harbor conditions, docking condition afloat, loading and unloading transitory conditions in port and loading
conditions encountered during ballast water exchange need not be considered.

3 Flooding Conditions

3.1 Floodable Holds (1 July 2006)

Each cargo hold is to be considered individually flooded up to the equilibrium waterline.

3.3 Loads
The still water loads in the flooded condition are to be calculated for the above cargo and ballast loading
conditions.
The wave loads in the flooded condition are assumed to be equal to 80% of those given in 3-2-1/3.5.

3.5 Flooding Criteria

To calculate the weight of flooded water, the following assumptions are to be made:
i) The permeability of empty cargo spaces and volume left in loaded cargo spaces above any cargo is
to be taken as 0.95.
ii) For the space below the top surface of bulk cargo in the loaded hold, appropriate permeabilities
and bulk cargo densities are to be used for any cargo carried. For iron ore, a permeability of 0.3
with a corresponding bulk density of 3.0 t/m3 (187 lb/ft3) is to be used. For cement, a permeability
of 0.3 with a corresponding bulk density of 1.3 t/m3 (81 lb/ft3) is to be used. In this respect,
“permeability” for bulk cargo means the ratio of the floodable volume between the particles,
granules or any larger piece of the bulk cargo, to the gross volume occupied by the bulk cargo.
For packed cargoes (such as steel mill products), permeability is to be based on the actual floodable volume.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 529
Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 5a Longitudinal of Bulk Carriers in Flooded Conditions 5C-3-A5a

5 Strength Assessment

5.1 Stress Calculation (1 July 2006)

For strength evaluation, the hull structure is to be assumed to remain fully effective in resisting the applied
loading. The actual hull girder bending stress, σbf, in kN/cm2 (tf/cm2, Ltf/in2) at any location is given by:
σbf = (Mswf + 0.8Mw)/SM
where
Mswf = still water bending moment, in kN-m (tf-m, Ltf-ft), in the flooded conditions for the
section under consideration
MW = wave bending moment, in kN-m (tf-m, Ltf-ft), as given in 3-2-1/3.5.2 for the section
under consideration
SM = gross hull girder section modulus, in cm2-m (in2-ft) for the section under
consideration.
The shear strength of the side shell and the inner hull (i.e., longitudinal bulkhead for double side skin bulk
carriers) at any location of the vessel, is to be checked according to the requirements specified in 3-2-1/3.9
in which FSW and FW are to be replaced respectively by FSWF and FWF, where:
FSWF = still water shear force, in kN (tf, Ltf), in the flooded conditions for the section under
consideration, corrected as per 3-2-1/3.9.3
FW = wave shear force, in kN (tf, Ltf), as given in 3-2-1/3.5.3 for the section under
consideration
FWF = 0.8FW

5.3 Strength Criteria

The calculated hull girder bending and shear stresses are not to exceed the values given below:
in bending: fbf = 17.5/Q kN/cm2 (1.784/Q tf/cm2, 11.33/Q Ltf/in2)
in shear: fsf = 11.0/Q kN/cm2 (1.122/Q tf/cm2, 7.122/Q Ltf/in2)
where Q is as defined in 3-2-1/5.5.

5.5 Buckling Strength

The buckling strength of the effective members of the longitudinal hull girder at the deck (from the deck to
the bottom of the upper wing tank) and bottom (from the bottom to the top of the lower wing tank) are to
be verified using the procedures given in 3-2-A4/1, 3-2-A4/3, 3-2-A4/5, and 3-2-A4/9.

530 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
PART Appendix 5b: Bulk Carriers in Flooded Conditions – Corrugated Transverse Watertight Bulkheads

5C
CHAPTER 3 Vessels Intended to Carry Ore or Bulk Cargoes
(150 meters (492 feet) or more in Length)

APPENDIX 5b Bulk Carriers in Flooded Conditions – Corrugated

Transverse Watertight Bulkheads (1 July 1998)

1 Corrugated Transverse Watertight Bulkheads (1998)

1.1 Application (1 July 2006)

This Appendix will apply to vertically corrugated transverse watertight bulkheads between two cargo holds
of Single or Double Skin construction, in bulk carriers of 150 m (492 ft) or more in length, constructed on or
after 1 July 2006, and intended to carry solid bulk cargoes having a density of 1.0 t/m3, (62.4 lb/ft3) or above.

1.3 Definitions
1.3.1 Homogeneous Loading
In Appendix 5C-3-A5b, a homogeneous loading is a loading condition wherein cargo is loaded in
two adjacent holds and wherein the ratio between the higher and lower filling levels, after
correction for different cargo densities, does not exceed 1.20.
1.3.2 Non-homogeneous Loading
Any loading condition not fitting the description in 5C-3-A5b/1.3.1 is considered non-homogeneous
for the application of Appendix 5C-3-A5b, except that non-homogeneous partial loading conditions
associated with multi-port loading and unloading operations for initially homogeneous loading
conditions are excluded.

1.5 Net Thickness and Nominal Design Corrosion Value

In calculating the scantlings for bulkhead and stool structures, the net thickness is to be used. The design
nominal corrosion value for these structures is to be taken as 3.5 mm (0.14 in.).

3 Load Model

3.1 General
The loads to be considered as acting on the bulkheads are those given by the combination of the cargo
loads with those induced by the flooding of one hold of single side skin construction and adjacent to the
bulkhead under examination. The scantlings of each bulkhead are to be checked using the design loading
conditions included in the longitudinal strength calculations and in the loading manual (see 3-2-1/7) and
the most severe combinations of cargoes and flooded water are to be used. Holds carrying packaged
cargoes are to be considered as empty holds for the application of Appendix 5C-3-A5b.
Vessels which are not designed to operate exclusively in non-homogenous conditions carrying heavy ore
cargoes [density greater than 1.78 t/m3 (111 lb/ft3)] are to have their bulkheads evaluated assuming the
hold is filled to the level of the deck at centerline with cargo at the nominal design density. The nominal
design density is defined as the maximum cargo mass in the hold divided by the hold volume.

3.3 Minimum Bulkhead Loading

For any bulkhead, the pressure due to the flooding water alone is to be considered as the minimum loading.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 531
Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 5b Bulk Carriers in Flooded Conditions –Corrugated Transverse Watertight Bulkheads 5C-3-A5b

3.5 Flooding Head

The flooding head hf (see 5C-3-A5b/Figure 1) is the distance, in m (ft), measured vertically with the vessel
in the upright position, from the point under consideration to a level located at a distance df, in m (ft), from
the baseline as given in the following table:

df
After Bulkhead of Foremost Hold (1) All Other Bulkheads
DWT Type of ρc ≥ 1.78 or ρc < 1.78 & ρc ≥ 1.78 or ρc < 1.78 &
(tonnes) Freeboard homo. cargo non-homo. homo. cargo non-homo.
≥ 50,000 or B60, B100 D 0.95D 0.9D 0.85D
< 50,000 and B0 0.95D 0.9D 0.85D 0.8D

Note: 1 Applicable for either case of flooding No.1 cargo hold or No.2 cargo hold

where D is the molded depth of the vessel, in m (ft), defined in 3-1-1/7.1 (see 5C-3-A5b/Figure 1).

3.7 Cargo Pressure in the Intact Holds

At each point of the bulkhead, the pressure pc, in N/cm2 (kgf/cm2, lbf/in2), is given by:
(1 − sin α )
pc = k1 ⋅ ρ c h1 ⋅
(1 + sin α )
The force Fc, in N (kgf, lbf), acting on a corrugation is given by:

(d1 − hDB − hLS ) 2 (1 − sin α )

Fc = k 2 ⋅ ρ c s1 ⋅ ⋅
2 (1 + sin α )
where
k1 = conversion factor, to be taken as 0.981 (0.01, 1/144)

ρc = bulk cargo density, in t/m3 (lb/ft3)

d1 = vertical distance, in m (ft), from the baseline to a horizontal plane corresponding to
the average height of the cargo (see 5C-3-A5b/Figure 1 )
h1 = vertical distance, in m (ft), from the calculation point to horizontal plane corresponding
to the average height of the cargo (see 5C-3-A5b/Figure 1)
α = angle of repose of the cargo, in degrees, that may generally be taken as 35° for iron
ore and 25° for cement
k2 = conversion factor, to be taken as 98.1 (10, 1/12)
s1 = spacing of corrugations, in cm (in.) (see 5C-3-A5b/Figure 2 )
hLS = mean height of the lower stool, in m (ft), from the inner bottom
hDB = height of the double bottom, in m (ft)

532 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 5b Bulk Carriers in Flooded Conditions –Corrugated Transverse Watertight Bulkheads 5C-3-A5b

FIGURE 1

hf
D
df
h1 V
d1

P1

3.9 Combined Cargo/Flooding Pressure in the Flooded Holds

3.9.1 Bulk Cargo Holds
Two cases are to be considered, depending on the values of d1 and df.

3.9.1(a) df ≥ d1
i) At each point of the bulkhead located at a distance between d1 and df from the baseline,
the pressure pc,f , in N/cm2 (kgf/cm2, lbf/in2), is given by:
pc, f = k1 ⋅ ρ ⋅ hf
ii) At each point of the bulkhead located at a distance less than d1 from the baseline, the
pressure pc, f , in N/cm2, (kgf/cm2, lbf/in2), is given by:
1 − sin α
pc, f = k1 ⋅ ρ ⋅ hf + k1 ⋅ [ρc −ρ ⋅ (1 − perm)] ⋅ h1 ⋅
1 + sin α
iii) The force Fc, f, in N (kgf, lbf), acting on a corrugation is given by:

⎡ ( d f − d 1 ) 2 p ⋅ ( d f − d 1 ) + ( p c , f ) le ⎤
Fc, f = k2 ⋅ s1 ⋅ ⎢ ρ ⋅ + ⋅ (d 1 − h DB − h LS )⎥
⎢⎣ 2 2 ⎥⎦

where
ρ = density of sea water, in t/m3 (lb/ft3)
k1 = as defined in 5C-3-A5b/3.7
hf = flooding head as defined in 5C-3-A5b/3.5
df = as given in 5C-3-A5b/3.5
perm = permeability of cargo, to be taken as 0.3 for ore (corresponding bulk cargo
density for iron ore may be 3.0 t/m3), coal cargoes and for cement
(corresponding bulk cargo density for cement may be 1.3 t/m3)
(pc, f)le = pressure, in N/cm2, (kgf/cm2, lbf/in2), at the lower end of the corrugation

k1, k2, s1, d1, h1, hDB, hLS, ρc, α are as given in 5C-3-A5b/3.7

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 533
Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 5b Bulk Carriers in Flooded Conditions –Corrugated Transverse Watertight Bulkheads 5C-3-A5b

3.9.1(b) df < d1
i) At each point of the bulkhead located at a distance between df and d1 from the baseline,
the pressure pc, f , in N/cm2, (kgf/cm2, lbf/in2), is given by:
(1 − sin α )
pc, f = k1 ⋅ ρ c h1 ⋅
(1 + sin α )
ii) At each point of the bulkhead located at a distance lower than df from the baseline, the
pressure pc, f , in N/cm2 (kgf/cm2, lbf/in2), is given by:
⎡1 − sin α ⎤
pc, f = k1 ⋅ ρ ⋅ hf + k1 ⋅ [ρc ⋅ h1 − ρ ⋅ (1 − perm) ⋅ hf ] ⋅ ⎢ ⎥
⎣1 + sin α ⎦
iii) The force Fc, f , in N (kgf, lbf) acting on a unit corrugation is given by:

⎡1 − sin α ⎤
ρ c ⋅ (d1 − d f ) ⎢ ⎥ + ( p c, f ) le
(d 1 − d f ) 2 (1 − sin α ) ⎣1 + sin α ⎦
Fc, f = k 2 ⋅ s1 ⋅ [ ρ c ⋅ ⋅ + ⋅ (d f − h DB − h LS )]
2 (1 + sin α ) 2
where
ρ = density of sea water, in t/m3 (lb/ft3)
perm = permeability of cargo, to be taken as 0.3 for ore (corresponding bulk cargo
density for iron ore may be 3.0 t/m3), coal cargoes and for cement
(corresponding bulk cargo density for cement may be 1.3 t/m3)
df = as given in 5C-3-A5b/3.5
(pc, f)le = pressure, in N/cm2, (kgf/cm2, lbf/in2), at the lower end of the corrugation

k1, k2, ρc, s1, d1, h1, hf, hDB, hLS, α are as given in 5C-3-A5b/3.7.

3.9.2 Empty Holds Pressure due to Flooding Water Alone

At each point of the bulkhead, the hydrostatic pressure pf, in N/cm2 (kgf/cm2, lbf/in2), induced by
the flooding water alone is given by:
pf = k1 ⋅ ρ ⋅ hf
The force Ff, in N (kgf, lbf), acting on a unit corrugation is given by:

(d f − h DB − h LS ) 2
Ff = k2 ⋅ s1 ⋅ ρ ⋅
2
where
ρ = as given in 5C-3-A5b/3.9.1(a)
df = as given in 5C-3-A5b/3.5
k1, k2, s, hDB , hLS are as given in 5C-3-A5b/3.7.

3.11 Resultant Pressure and Force

3.11.1 Homogeneous Loading Conditions
At each point of the bulkhead structures, the resultant pressure p, in N/cm2 (kgf/cm2, lbf/in2),
acting on the bulkhead is given by:
p = pc, f − 0.8Pc or p = pf whichever is greater
The resultant force F, in N (kgf, lbf), acting on a unit corrugation is given by:
F = Fc, f − 0.8Fc or F = Ff whichever is greater

534 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 5b Bulk Carriers in Flooded Conditions –Corrugated Transverse Watertight Bulkheads 5C-3-A5b

3.11.2 Non-homogeneous Loading Conditions

At each point, the resultant pressure p, in N/cm2 (kgf/cm2, lbf/in2), acting on the bulkhead is given by:
p = pc, f or p = pf whichever is greater
The resultant force F, in N (kgf, lbf), acting on a unit corrugation is given by:
F = Fc, f or F = Ff whichever is greater

FIGURE 2

L
C

l l

n = neutral axis of the corrugations a

φ tw

s1 tf

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 535
Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 5b Bulk Carriers in Flooded Conditions –Corrugated Transverse Watertight Bulkheads 5C-3-A5b

5 Bending Moment and Shear Force

The bending moment, M, and the shear force, Q, in the bulkhead corrugations are obtained using the
formulae given in 5C-3-A5b/5.1 and 5C-3-A5b/5.3. The M and Q values are to be used for the checks in
5C-3-A5b/7.3 and 5C-3-A5b/11.

5.1 Bending Moment

The design bending moment M, in N-cm (kgf-cm, lbf-in.), for the bulkhead corrugations is given by:
M = 12.5Fl (SI/MKS units) M = 1.5Fl (US units)
where
F = resultant force, in N (kgf, lbf), as given in 5C-3-A5b/3.11
l = span of the corrugation, in m (ft), to be taken according to 5C-3-A5b/Figure 2 and
5C-3-A5b/Figure 3

5.3 Shear Force

The shear force Q, in N (kgf, lbf), at the lower end of the bulkhead corrugations is given by:
Q = 0.8F
where
F = as given in 5C-3-A5b/3.11

FIGURE 3 (2004)

See
Note

l l l l l

Note: For the definition of l, its upper end is not to be taken more than a distance from the deck at the
centerline equal to:
- Three (3) times the depth of corrugations, in general
- Two (2) times the depth of corrugations, for rectangular stool

536 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 5b Bulk Carriers in Flooded Conditions –Corrugated Transverse Watertight Bulkheads 5C-3-A5b

7 Strength Criteria

7.1 General
The following criteria are applicable to transverse bulkheads with vertical corrugations (see 5C-3-A5b/Figure 2).
For vessels of 190 m or more in length, these bulkheads are to be fitted with a bottom stool, and generally
with an upper stool below deck. For smaller vessels, corrugations may extend from inner bottom to deck.
The corrugation angle φ shown in 5C-3-A5b/Figure 2 is not to be less than 55°.
Requirements for local net plate thickness are given in 5C-3-A5b/13.
In addition, the criteria as given in 5C-3-A5b/7.7 and 5C-3-A5b/9 are to be complied with.
The thickness and material of the lower part of corrugations considered in the application of 5C-3-A5b/7.3
and 5C-3-A5b/9.1 are to be maintained for a distance from the inner bottom (if no lower stool is fitted) or
the top of the lower stool not less than 0.15l, where l is defined in 5C-3-A5b/5.1
The thickness and material of the middle part of corrugations, as considered in the application of 5C-3-A5b/7.3
and 5C-3-A5b/9.3, are to be maintained up to the level within 0.3l from the deck (if no upper stool is fitted)
or the bottom of the upper stool.
The section modulus of the corrugation in the remaining upper part of the bulkhead is not to be less than
75% of that required for the middle part, corrected for any difference in yield stress.

7.3 Bending Capacity

The bending capacity of the corrugation is to comply with the following relationship:
M
≤ 0.95
0.5 ⋅ SM le ⋅ f y ,le + SM m ⋅ f y ,m

where
M = bending moment, in N-cm (kgf-cm, lbf-in), as given in 5C-3-A5b/5.1
SMle = section modulus, in cm3 (in3), at the lower end of corrugations, to be calculated
according to 5C-3-A5b/9.1. SMle is to be taken not greater than SM l′e
Q ⋅ h g − 0.5 ⋅ k ⋅ h g2 ⋅ s1 ⋅ p g
SM l′e = SMg + k ⋅
f y , le

k = 100 (100, 12)

SMg = section modulus, in cm3 (in3), of the corrugations calculated, according to
5C-3-A5b/9.3, in way of the upper end of shedder or gusset plates, as applicable
Q = shear force, in N (kgf, lbf), as given in 5C-3-A5b/5.3
hg = height, in m (ft), of shedders or gusset plates, as applicable (see 5C-3-A5b/Figure 4,
5C-3-A5b/Figure 5, and 5C-3-A5b/Figure 6)
s1 = as given in 5C-3-A5b/3.7
pg = resultant pressure, in N/cm2(kgf/cm2, lbf/in2), as defined in 5C-3-A5b/3.11,
calculated at the middle of the shedders or gusset plates, as applicable
SMm = section modulus, in cm3 (in3), at the mid-span of corrugations, to be calculated
according to 5C-3-A5b/9.3. SMm is to be taken not greater than 1.15 SMle
fy, le = minimum specified yield stress, in N/cm2 (kgf/cm2, lbf/in2), of the material for the
lower end of corrugations
fy, m = minimum specified yield stress, in N/cm2 (kgf/cm2, lbf/in2), of the material for the
mid-span of corrugations

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 537
Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 5b Bulk Carriers in Flooded Conditions –Corrugated Transverse Watertight Bulkheads 5C-3-A5b

7.5 Effective Shedder Plates

In order for shedder plates to be considered effective for the application of 5C-3-A5b/9.1.1, the following
requirements are to be complied with:
7.5.1
The shedder plate lies in one plane, i.e., is not knuckled.
7.5.2
The shedder plate is welded to the corrugations and the top of the lower stool by one side penetration
welds or equivalent.
7.5.3
The shedder plate angle with respect to the base line is at least 45° and the lower edge is in line
with the stool side plating.
7.5.4
The shedder plate is to have a thickness not less than 75% of that of the corrugation flange.
7.5.5
Shedders are to have material properties at least equal to those for the flanges.

7.7 Effective Gusset Plates

In order for gusset plates to be considered effective for the application of 5C-3-A5b/9.1.2, in combination
with shedder plates having thickness, material properties and welded connections in accordance with the
above, the following requirements are to be complied with:
7.7.1
The height of the gusset plates is not to be less than half the corrugation flange width.
7.7.2
The gusset plates are to be fitted in line with the stool side plating.
7.7.3
Gusset plates are to be generally welded to the top of the lower stool by full penetration welds,
and to the corrugations and shedder plates by one side penetration welds or equivalent.
7.7.4
Gusset plates are to have thickness and material properties at least equal to those provided for the
flanges.

538 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 5b Bulk Carriers in Flooded Conditions –Corrugated Transverse Watertight Bulkheads 5C-3-A5b

FIGURE 4
Symmetric Shedder Plates

SHEDDER
PLATE
hg

LOWER
STOOL

FIGURE 5 FIGURE 6
Asymmetric Shedder Plates Symmetric Gusset/Shedder Plates

GUSSET
PLATE
SHEDDER
PLATE
hg hg

1 1

LOWER
STOOL LOWER
STOOL

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 539
Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 5b Bulk Carriers in Flooded Conditions –Corrugated Transverse Watertight Bulkheads 5C-3-A5b

9 Section Properties
All section properties are to be calculated using the net plate thickness.
The section modulus of corrugations are to be calculated on the basis of the procedure given below in
5C-3-A5b/9.1 and 5C-3-A5b/9.3

9.1 Section Modulus at the Lower End of Corrugations

The section modulus is to be calculated with the compression flange having an effective flange width not
greater than one half of bef as given in 5C-3-A5b/9.5.
If the corrugation webs are not supported by local brackets below the stool top (or below the inner bottom)
in the lower part, the section modulus of the corrugations is to be calculated considering the corrugation
webs 30% effective.
9.1.1
Provided effective shedder plates, as defined in 5C-3-A5b/7.5, are fitted above a horizontal stool
top plate, (see 5C-3-A5b/Figure 4 and 5C-3-A5b/Figure 5), when calculating the section modulus
of corrugations at the lower end (cross-section a-a), the area of each applicable flange may be
increased by (k a t f ⋅ t sh ) cm2 (in2)
where
k = 1.25 (1.25, 1.5)
a = width, in m (ft), of the corrugation flange (see 5C-3-A5b/Figure 2)
tsh = net shedder plate thickness, in mm (in.); not to be taken greater than tf
tf = net flange thickness, in mm (in.)

9.1.2
Provided effective gusset plates, as defined in 5C-3-A5b/7.7, are fitted (see 5C-3-A5b/Figure 6),
when calculating the section modulus of corrugations at the lower end (cross-section 1), the area
of each applicable flange may be increased by (k · hg · tf) cm2 (in2) where:
k = 3.5 (3.5, 4.2)
hg = height of gusset plate, in m (ft), see 5C-3-A5b/Figure 6, not to be taken
greater than
⎛ 10 ⎞
⎜ ⋅ s gu ⎟
⎝7 ⎠
sgu = width of the gusset plates, in m (ft)
tf = net flange thickness, in mm (in.)

9.1.3
If the sloping stool top plate is at least 45 degrees to the horizontal, the section modulus of the
corrugations may be calculated considering the corrugation webs fully effective. In case effective
gusset plates are fitted, when calculating the section modulus of corrugations, the area of the
flange may be increased as specified in 5C-3-A5b/9.1.2 above. No credit can be given to shedder
plates only. If the angle to the horizontal is less than 45 degrees, the effectiveness of the web may
be obtained by linear interpolation between 30% at 0 degrees and 100% at 45 degrees.

9.3 Section Modulus of Corrugations at Cross-Sections other than the Lower End
The section modulus is to be calculated with the corrugation webs considered effective and the compression
flange having an effective flange width, not greater than one half of bef, as given in 5C-3-A5b/9.5.

540 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 5b Bulk Carriers in Flooded Conditions –Corrugated Transverse Watertight Bulkheads 5C-3-A5b

9.5 Effective Width of the Compression Flange

The effective width bef, in cm (in.), of the compression flange is given by:
bef = Ce · a
where
2.25 1.25
Ce = − for β > 1.25
β β2
Ce = 1.0 for β ≤ 1.25

a fy
β= ⋅
tf E

tf = net flange thickness, in cm (in.)

a = width, in cm (in.), of the corrugation flange (see 5C-3-A5b/Figure 2)
fy = minimum specified yield stress of the material, in N/cm2 (kgf/cm2, lbf/in2)
E = modulus of elasticity of the material, in N/cm2 (kgf/cm2, lbf/in2)

11 Shear Strength

11.1 Shear Stress

The shearing stress fs in the corrugation web plate is calculated as follows:
Q
fs =
c ⋅ sin⋅ φ ⋅ t w
and is not to exceed the allowable value fa given by:
fa = 0.5fy
Q = shear force in web, in N (kgf, lbf), calculated in accordance with 5C-3-A5b/5.3
fy = minimum specified yield stress, in N/cm2 (kgf/cm2, lbf/in2), of the web material
φ = corrugation angle (see 5C-3-A5b/Figure 2)
c = corrugation web length (see 5C-3-A5b/Figure 2), in cm (in.)
tw = net thickness of the corrugation web plating, in cm (in.)

11.3 Shear Buckling

The buckling check is to be performed for the web plates at the corrugation ends.
The shear stress fs is not to exceed the critical value τc, in N/mm2, (kgf/cm2, psi), as given in Appendix 3-2-A4,
with kt = 6.34 and tb = net thickness of the corrugation web plating.

13 Local Net Plate Thickness

The bulkhead local net plate thickness tn or tw1, in mm (in.), is given by:

p
tn = 0.483sn
fy

p
tw1 = 0.483sw
fy

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 5b Bulk Carriers in Flooded Conditions –Corrugated Transverse Watertight Bulkheads 5C-3-A5b

where
sn, (sw) = width, in mm (in.), of the narrower (wider) plate of the corrugation (a or c as shown
in 5C-3-A5b/Figure 2 )
p = resultant pressure, in N/cm2 (kgf/cm2, lbf/in2), as defined in 5C-3-A5b/3.11, at the
bottom of each strake of plating. The net thickness of the lowest strake is to be
determined using the resultant pressure at the top of the lower stool, or at the inner
bottom, if no lower stool is fitted or at the top of shedders, if shedder or
gusset/shedder plates are fitted.
fy, = minimum specified yield stress, in N/cm2 (kgf/cm2, lbf/in2), of the material
In addition, where the proposed net thickness tnp of narrower plating is less than tw1 given above, the net
thickness of the wider plating is to be not less than tw2, in mm (in.), obtained by the following:

tw2 = 2 ⋅ t w21 − t npn

2

tnp = proposed net thickness of the narrower plate, in mm (in.)

15 Stool Construction
The scantlings, details and arrangements of the upper and lower stool structures are to comply with the
requirements of 5C-3-4/25.9 to 5C-3-4/25.13.

17 Local Scantlings and Details

17.1 Shedder Plates

In addition to the requirements of 5C-3-A5b/7.5, shedder plates are to have a net thickness not less than t
in 5C-3-4/23.1 with the pressure, p, determined as per 5C-3-A5b/3.11 at the middle of the shedder.

17.3 Gusset Plates

In addition to the requirements of 5C-3-A5b/7.7, gusset plates are to comply with the following:
The gusset plating is to be sized in accordance with 5C-3-A5b/13 with s taken as the distance between
gusset stiffeners or the dimension – (a + 2c cos α) or hg, whichever is less if no stiffening is provided. The
pressure, p is to be taken at the lower edge of the gusset.
Gusset plate stiffeners, where fitted, are to comply with the net SM in 5C-3-4/23.3 with the pressure p
determined as per 5C-3-A5b/3.9, c1 = 1.0, k = 8 (8, 125) and fb = 0.90 Sm fy.

542 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
PART Appendix 5c: Bulk Carriers in Flooded Conditions – Permissible Cargo Loads in Holds

5C
CHAPTER 3 Vessels Intended to Carry Ore or Bulk Cargoes
(150 meters (492 feet) or more in Length)

APPENDIX 5c Bulk Carriers in Flooded Conditions – Permissible

Cargo Loads in Holds (1 July 1998)

1 Permissible Cargo Loads in Holds

1.1 Application (1 July 2006)

This Appendix will apply to cargo loading in each hold of Single or Double Side Skin construction in bulk
carriers of 150 m (492 ft) or more in length, constructed on or after 1 July 2006, intended to carry solid
bulk cargoes having a density of 1.0 t/m3 (62.4 lb/ft3) or more, and having conventional double bottom
structures formed by a grillage consisting of regularly spaced floors and girders with a complete inner
bottom supported by hopper tanks at the side and transverse bulkheads at the ends.

1.3 Net Thickness and Nominal Design Corrosion Value

In calculating the shear strength, the net thickness of floors and girders is to be used. The nominal design
corrosion value for the floors and girders is to be taken as 2.5 mm (0.10 in.).

1.5 Check of Proposed Loading Conditions

All proposed cargo loading conditions including the following:
• homogeneous loading conditions;
• non-homogeneous loading conditions;
• packaged cargo conditions (such as steel mill products),
are to be checked against the allowable load in the flooded condition calculated in accordance with 5C-3-A5c/7.
In general, the maximum bulk cargo density to be carried is to be considered in calculating the allowable
load in the hold. In no case is the allowable hold loading in flooded condition to be taken greater than the
design hold loading in intact conditions.

3 Load Model

3.1 General
The loads considered in the assessment of allowable load in cargo holds of single side skin construction are
those by the external sea pressure, the combination of the cargo and flooded water in the hold and the
weight of the contents of the double bottom space in way of the hold.

3.3 Flooding Head

The flooding head hf (see 5C-3-A5c/Figure 1) is the distance, in m (ft), measured vertically with the vessel
in the upright position, from the point under consideration to a level located at a distance df, in m (ft), from
the baseline given in the following table:

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Appendix 5c Bulk Carriers in Flooded Conditions –Permissible Cargo Loads in Holds 5C-3-A5c

df
DWT (tonnes) and/or Type of Freeboard Foremost Hold All Other Holds
≥ 50,000 or B60, B100 D 0.9D
<50,000 and B0 0.95D 0.85D

where D is the distance, in m (ft), from the baseline to the freeboard deck at side amidships, as defined in
3-1-1/7.1.

3.5 External Sea Water Head

The external sea water head (E), in m (ft), is measured vertically from the baseline of the vessel with the
vessel in the upright position, and is given by the following:
E = df − 0.1D
where df, D are as defined above.

FIGURE 1

hf

D
h1 d1 df
h1 V
d1

V= Volume of cargo

5 Shear Strength and Shear Capacity

5.1 Floor Shear Strength

The shear strength of the floor panel adjacent to hoppers, Sf1, and in way of any openings in the same
panel, Sf2, are given by the following:
fs
Sf1 = 10-3mAf in kN (tf, Ltf)
η1
fs
Sf2 = 10-3mAf, h in kN (tf, Ltf)
η2
where
Af = sectional area of the floor panel adjacent to hoppers, in cm2 (in2)

Af, h = sectional area in way of the openings in the same panel, in cm2 (in2)

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 5c Bulk Carriers in Flooded Conditions –Permissible Cargo Loads in Holds 5C-3-A5c

fs = allowable shear stress, in kN/cm2 (tf/cm2, Ltf/in2), to be taken equal to the lesser of:
k ⋅ f y 0.6 fy
or
(s / t net )0.8 k1 3
k = 1.022 (0.41, 0.529)
k1 = 1000 (1000, 2240)
For floors next to stools or transverse bulkheads, as identified in 5C-3-A5c/Figure 2, fs may be taken equal to:

fy
k1 3

fy = minimum specified yield stress of the material, in N/cm2 (kgf/cm2, lbf/in2)

m = 0.50 for the floor next to the stool or transverse bulkhead, see 5C-3-A5c/Figure 2
= 1.0 for all other floors
η1 = 1.10
η2 = 1.20, in general. If the opening in the floor is reinforced by a ring stiffener or “boxed”
by additional panel stiffeners, η2 may be taken as 1.10

FIGURE 2

Transverse bulkhead
Lower stool

Floor adjacent Floor adjacent to the

to the stool transverse bulkhead

L
C

Girders

Floors

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 5c Bulk Carriers in Flooded Conditions –Permissible Cargo Loads in Holds 5C-3-A5c

5.3 Girder Shear Strength

The shear strength of the girder panel adjacent to stools (or transverse bulkheads, if no stool is fitted), Sg1,
and in way of the largest of any openings in the same panel, Sg2, are given by the following:
fs
Sg1 = 10-3Ag in kN (tf, Ltf)
η1
fs
Sg2 = 10-3Ag,h in kN (tf, Ltf)
η2
where
Ag = sectional area of the girder panel adjacent to stools (or transverse bulkheads, if no
stool is fitted), in cm2 (in2)
Ag, h = sectional area in way of the largest opening in the same panel, in cm2 (in2)
fs = allowable shear stress, in kN/cm2 (tf/cm2, Ltf/in2), as given in 5C-3-A5c/5.1
η1 = 1.10
η2 = 1.15 in general. If the opening in the girder is reinforced by a ring stiffener or
‘boxed’ by additional panel stiffeners, η2 may be taken as 1.10.

5.5 Shear Capacity of Double Bottom

The shear capacity, C, of the double bottom, is defined as the sum of the shear strength at each end of
complete floors and girders attached directly to the boundary hopper or stool/bulkhead.
Where in the end holds, girders run out and are not directly attached to the boundary stool/bulkhead, their
strength is to be evaluated for the attached end only.
Only the floors and girders inside the hold boundaries formed by the hoppers and stools (or transverse
bulkheads if no stool is fitted) may be considered. The hopper side girders and the floors directly below the
connection of the bulkhead stools (or transverse bulkheads if no stool is fitted) to the inner bottom are not
to be included.
The shear capacity Ce and Ch for use with Z1 and Z2 in 5C-3-A5c/7 are to be in accordance with the above
definition, with consideration for the type of shear strength, as follows:
Ch = shear capacity of the double bottom, in kN (tf, Ltf), considering for each floor, the
lesser of the shear strengths Sf1 and Sf2 (see 5C-3-A5c/5.1) and, for each girder, the
lesser of the shear strengths Sg1 and Sg2 (see 5C-3-A5c/5.3)
Ce = shear capacity of the double bottom, in kN (tf, Ltf), considering for each floor, the
shear strength Sf1 (see 5C-3-A5c/5.1) and, for each girder, the lesser of the shear
strengths Sg1 and Sg2 (see 5C-3-A5c/5.3)
Where the geometry and/or the structural arrangement of the double bottom differs from the above, the
shear capacity C of double bottom may be determined by an approved method.

7 Allowable Cargo Load in Holds

The allowable cargo load in hold W, is given by:
ρc ⋅V
W = k1⋅ in kN (tf, Ltf)
F
where
k1 = conversion factor, to be taken as 9.81 (1.0, 1/2240)
F = 1.10 for bulk cargoes
= 1.05 for steel mill products

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 5c Bulk Carriers in Flooded Conditions –Permissible Cargo Loads in Holds 5C-3-A5c

ρc = cargo density, in t/m3 (lb/ft3). Generally, for bulk cargoes the maximum density to be
carried is to be considered.
V = volume, in m3 (ft3), occupied by cargo at a level h1
h1 = average height of the cargo, in m (ft) – See 5C-3-A5c/Figure 1

X
=
k1 ⋅ ρ c
X = for bulk cargoes, the lesser of X1 or X2
Z + k1 ⋅ ρ ⋅ ( E − h f )
X1 =
ρ
1− (1 − perm)
ρc
X2 = Z + k1 ρ ⋅ (E − hf ⋅ perm)
= for steel mill products, X may be taken as X1, using perm = 0.
ρ = sea water density, 1.025 t/m3 (64 lb/ft3)
E = external sea water head, in m (ft), as defined in 5C-3-A5c/3.5
hf = flooding head, in m (ft), as defined in 5C-3-A5c/3.3
perm = cargo permeability, (for bulk cargoes, the ratio of floodable volume between the
particles, granules or any larger piece of the cargo, to the gross volume occupied by
the bulk cargo; but need not be taken greater than 0.3)
Z = the lesser of Z1 and Z2 given by:
C h − M DB ,h
Z1 =
ADB;h

C e − M DB ,e
Z2 =
ADB ,e

Ch , Ce = as defined in 5C-3-A5c/5.5
MDB, h = load in kN (tf, Ltf) of the contents of the double bottom space within ADB, h in way of
the hold under consideration
MDB, e = load in kN (tf, Ltf) of the contents of the double bottom space within ADB, e in way of
the hold under consideration
i =n
ADB, e = ∑S
i =1
i ⋅ B DB , i

i =n
ADB, e = ∑S
i =1
i ⋅ (B DB − s )

n = number of floors between stools (or transverse bulkheads, if no stool is fitted)

Si = space of i-th -floor, in m (ft)
BDB, i = BDB − s for the floor for which Sf1 is used in determining Ch or Ce (see 5C-3-A5c/5.5)
BDB, i = BDB, h for the floor for which Sf2 is used in determining Ch (see 5C-3-A5c/5.5)
BDB = breadth, in m (ft), of double bottom between hoppers (see 5C-3-A5c/Figure 3)
BDB, h = distance, in m (ft), between the two considered openings (see 5C-3-A5c/Figure 3)
s = spacing, in m (ft), of double bottom longitudinals next to hoppers

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 5c Bulk Carriers in Flooded Conditions –Permissible Cargo Loads in Holds 5C-3-A5c

FIGURE 3

BDB, h

BDB

548 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
PART Appendix 6: Harmonized System of Notations and Corresponding Design Loading Conditions for Bulk Carriers

5C
CHAPTER 3 Vessels Intended to Carry Ore or Bulk Cargoes
(150 meters (492 feet) or more in Length)

APPENDIX 6 Harmonized System of Notations and

Corresponding Design Loading Conditions for
Bulk Carriers (1 July 2003)

1 General

1.1
This Appendix is intended to improve the transparency of the Rules regarding cargo carrying capabilities
of bulk carriers by applying a harmonized system of notations for corresponding design loading conditions
with respect to strength and stability. This Appendix is an integral part of the ABS Rules.

1.3
This Appendix is not intended to prevent any other loading conditions from being included in the loading
manual for which calculations are to be submitted as required by the Rules, nor is it intended to replace in
any way the required loading manual/instrument.

1.5
The assigned notations and corresponding design loading conditions are to be included in the loading
manual for each vessel and are to be identified as such. It is to be noted that these design loading conditions
are developed to allow maximum operational flexibility and are not intended as specific sample operating
conditions.
A bulk carrier in actual operation may be loaded differently from the design loading conditions, provided
the limitations for longitudinal and local strength and stability as defined in the loading manual and loading
instrument onboard are not exceeded.

1.7
The heavy ballast condition, as required by 5C-3-A6/7.1.4, is to be used while the vessel is operated in
heavy weather.

3 Application

3.1
This Appendix is applicable to bulk carriers as defined in 5C-3-1/1.5.1 with length as defined in 3-1-1/3.1
of 150 meters (492 feet) or more and are contracted for new construction on or after 1 July 2003.

3.3
The loading conditions listed under 5C-3-A6/7.1 are to be used, as may be indicated in the respective
paragraph, for the longitudinal strength, local strength and stability criteria in the Rules. The loading
conditions listed under 5C-3-A6/7.3 are to be used for local strength. See 5C-3-A6/Table 1.

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Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 6 Harmonized System of Notations and Corresponding Design Loading Conditions for
Bulk Carriers 5C-3-A6

5 Harmonized Notations

5.1 Mandatory Notations and Notes

5.1.1 Mandatory Notations
One of the following notations will be assigned to any given ship in association with the design
loading conditions in 5C-3-A6/7.1.
BC-A: for bulk carriers designed to carry dry bulk cargoes of cargo density 1.0 tonne/m3
and above with specified holds empty at the summer load line, in addition to in
all holds
BC-B: for bulk carriers designed to carry dry bulk cargoes of cargo density of 1.0
tonne/m3 and above in all cargo holds, without any hold being specified empty
BC-C: for bulk carriers designed to carry dry bulk cargoes of cargo density less than 1.0
tonne/m3
5.1.2 Supplementary Notes
For all BC-A ships, a supplementary note describing all approved combinations of specified empty
holds are to be entered in the Record:
(all approved combinations of specified empty holds)
This supplementary note will be placed immediately after the mandatory notation in 5C-3-A6/5.1.1.

5.3 Additional Notations

Additional notations will be entered in the Record to identify the particular loading condition, wherever it
is chosen for the design
This supplementary note will be placed immediately after the mandatory notation in 5C-3-A6/5.1.1 or,
where applicable, the supplementary notation in 5C-3-A6/5.1.2.
(maximum cargo density (in tonnes/m3)) – for BC-A and BC-B if the maximum cargo
density is less than 3.0 tonne/m3 ;
(no MP) – for all notations when the vessel has not been designed for loading and unloading in
multiple ports. See 5C-3-A6/7.3.3.

7 Design Loading Conditions for Harmonized Notations

7.1 General Loading Conditions

The following loading conditions are to be applied in association with the harmonized system of bulk
carrier notations in 5C-3-A6/5.1.
7.1.1 BC-C
Fully homogeneous cargo condition with all cargo holds, including hatchways, 100% full at the
summer load line with all ballast tanks empty.
7.1.2 BC-B
The design loading conditions are:
7.1.2(a) As required for BC-C in 5C-3-A6/7.1.1, plus:
7.1.2(b) Heavy cargo condition wherein cargoes having a density of 3.0 tonnes/m3 (187 lb/ft3) are
loaded in all cargo holds at the same filling rate (cargo volume/hold cubic capacity) at the summer
load line with all ballast tanks empty.

550 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 6 Harmonized System of Notations and Corresponding Design Loading Conditions for
Bulk Carriers 5C-3-A6

7.1.2(c) Where the vessel is not intended to carry 3.0 tonnes/m3 (187 lb/ft3) or higher density
cargoes, the design may be based on the maximum density of the cargo the vessel is intended to
carry. In such cases, the maximum density of the cargo that the vessel is allowed to carry will be
distinguished by an additional notation (maximum cargo density (in tonnes/m3)) following
a bulk carrier notation. See 5C-3-A6/5.3 and 5C-3-1/1.1.
7.1.3 BC-A
The design loading conditions are:
7.1.3(a) As required for BC-B in 5C-3-A6/7.1.2, plus:
7.1.3(b) At least one cargo loaded condition with specified holds empty, with cargo density 3.0
tonnes/m3 (187 lb/ft3), and at the same filling rate (cargo volume/hold cubic capacity) in all loaded
cargo holds at the summer load line with all ballast tanks empty.
7.1.3(c) Approved combination of specified empty holds is to be indicated by a supplementary
note “(holds 1, 2… may be empty)”. Where more than one combination is approved, each
approved combination is to be indicated, e.g., “(holds 1, 3, 5 and 7 or holds 2, 4 and 6 may
be empty)” See 5C-3-A6/5.1.2.
7.1.3(d) Where the vessel is not intended to carry 3.0 tonnes/m3 (187 lb/ft3) or higher density
cargoes with specified hold(s) empty, the design may be based on the maximum density of the
cargo the vessel is intended to carry. In such cases, the maximum density of the cargo that the
vessel is allowed to carry in that loading condition is to be included in the additional notation in
the Record which will read “(holds 1, 2… may be empty, with maximum cargo density ρ
tonnes/m3)”. See 5C-3-A6/5.3.
7.1.4 Ballast Conditions (applicable to all notations)
7.1.4(a) Ballast Tank Capacity. All bulk carriers are to have ballast tanks of sufficient capacity
so disposed to fulfil at least the following requirements:
i) Normal Ballast Condition. Normal ballast condition for the purpose of this Appendix is a
ballast (no cargo) condition where:
1. The ballast tanks may be full, partially full or empty. Where partially full option
is exercised, the conditions in the second paragraph of 3-2-1/3.3 are to be complied
with,
2. Any cargo hold or holds adapted for the carriage of water ballast at sea are to be
empty,
3. The propeller is fully immersed, and
4. The trim is by the stern and is not to exceed 0.015L, where L is the length
between perpendiculars of the vessel.
In the assessment of the propeller immersion and trim, the drafts at the forward and after
perpendiculars may be used.
ii) Heavy Ballast Condition. Heavy ballast condition for the purpose of this Appendix is a
ballast (no cargo) condition utilizing all ballast tanks including one or more cargo holds
adapted and designated for the carriage of water ballast at sea. In this condition,
1. The ballast tanks may be full, partially full or empty. Where partially full option
is exercised, the conditions in the second paragraph of 3-2-1/3.3 are to be complied
with,
2. At least one cargo hold adapted for the carriage of water ballast at sea where
required or provided, is to be full,
3. The propeller immersion I/D is to be at least 60% where
I = the distance from propeller centerline to the waterline
D = propeller diameter,

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 6 Harmonized System of Notations and Corresponding Design Loading Conditions for
Bulk Carriers 5C-3-A6

4. The trim is to be by the stern and is not to exceed 0.015L, where L is the length
between perpendiculars of the ship, and
5. The molded forward draft in the heavy ballast condition is not to be less than the
smaller of 0.03L or 8 m (26.25 ft)
7.1.4(b) Strength Requirements
i) Normal Ballast Condition
1. The structures of bottom forward are to be strengthened in accordance with the
requirements of 5C-3-6/13 against slamming for the condition of 5C-3-A6/7.1.4(a)i)
at the lightest forward draft,
2. The longitudinal strength requirements are to be complied with for the condition
of 5C-3-A6/7.1.4(a)i), and
3. In addition, the longitudinal strength requirements are to be met with all ballast
tanks 100% full.
ii) Heavy Ballast Condition
1. The longitudinal strength requirements are to be met for the condition of
5C-3-A6/7.1.4(a)ii),
2. In addition to the conditions in 5C-3-A6/7.1.4(b)ii)1, the longitudinal strength
requirements are to be met under a condition with all ballast tanks 100% full and
one cargo hold adapted and designated for the carriage of water ballast at sea,
where provided, 100% full, and
3. Where more than one hold is adapted and designated for the carriage of water
ballast at sea, it will not be required that two or more holds be assumed 100% full
simultaneously in the longitudinal strength assessment, unless such conditions
are expected in the heavy ballast condition. Unless each hold is individually
investigated, the designated heavy ballast hold and any/all restrictions for the use
of other ballast hold(s) are to be indicated in the loading manual
7.1.5 Departure and Arrival Conditions
Unless otherwise specified, each of the design loading conditions in 5C-3-A6/7.1 through
5C-3-A6/7.4 is to be investigated for the arrival and departure conditions, as defined below:
• Departure condition: with bunker tanks not less than 95% full and other consumables 100%.
• Arrival condition: with all consumables 10%
7.1.6 Summary of Applicable Requirements
For the application of Rule requirements in the respective loading conditions in 5C-3-A6/7.1, see
5C-3-A6/Table 1 below.

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 Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 6 Harmonized System of Notations and Corresponding Design Loading Conditions for
Bulk Carriers 5C-3-A6

TABLE 1
Application of 5C-3-A6/7.1

Emp. Dep or Long’l Strength Stability Prop. Fwd Bridge

z Notation Density Hold Arr Intact Dmged Intact Dmged Imm. Trim Draft Visibility
7.1.1
<1.0 N D&A Y NA Y NA NA NA NA Y
BC-C
Cargo

7.1.2
>1.0 N D&A Y Y Y Y NA NA NA Y
BC-B
7.1.3
>1.0 Y D&A Y Y Y Y NA NA NA Y
BC-A
Topic Cond’n
7.1.4(a) Normal D&A Y Y (1) Y NA 50% Y NA Y
Ballast

Capacity Heavy D&A Y Y (1) Y NA 60% Y Y Y

7.1.4(b) Normal D&A Y Y (1) Y NA N N NA (2) N
L. Strength Heavy D&A Y Y (1)
Y NA N N NA N
Notes:
1 Except BC-C for which longitudinal strength requirements in damaged condition at ballast draft are not applicable.
2 At the lightest forward draft, slamming loads for assessment of structures of bottom forward are to be determined
in accordance with the requirements of 5C-3-6/13.

7.3 Local Loading Conditions for Each Individual Hold

7.3.1 Definitions
The maximum allowable or minimum required cargo mass in a cargo hold, or in two adjacent
holds, is related to the net load on the double bottom. The net load on the double bottom is a function
of draft, cargo mass in the cargo hold, as well as the mass of any contents in double bottom tanks.
The following definitions apply:
MH: the actual cargo mass in a cargo hold corresponding to a fully homogeneous cargo
loaded condition at the molded summer draft (d). See also 3-2-A2/Table 1 item 2.2.4.
MFull: = MH, except that in calculating MFull, the homogeneous cargo density is not to be
taken as less than 1.0 tonne/m3 (62.4 lb/ft3)
MHD: the maximum cargo mass allowed to be carried in a cargo hold according to design
loading condition(s) with specified holds empty at the molded summer draft (d).
7.3.2 General Conditions for All Ships
7.3.2(a)
i) Any cargo hold is to be capable of carrying at least MFull with fuel oil tanks in double
bottom in way of the cargo hold, if any, 100% full and ballast water tanks in the double
bottom in way of the cargo hold empty, at d.
ii) The maximum allowable hold mass for a draft less than d may be obtained by adjusting
the value obtained by 5C-3-A6/7.3.2(a)i) for the loss of buoyancy due to the decrease in draft.
7.3.2(b)
i) Any cargo hold is to be capable of being immersed to d with a mass in hold not exceeding
0.5MH and with all double bottom tanks in way of the cargo hold empty.
ii) The minimum required hold mass for a draft less than d may be obtained by adjusting the
value obtained by 5C-3-A6/7.3.2(b)i) for the loss of buoyancy due to the decrease in draft,
subject to 5C-3-A6/7.3.2(d).

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 6 Harmonized System of Notations and Corresponding Design Loading Conditions for
Bulk Carriers 5C-3-A6

7.3.2(c)
i) Any cargo hold is to be capable of being immersed to the deepest ballast draft (dB) with
the cargo hold and all double bottom tanks in way of the cargo hold empty.
ii) The minimum required mass for a draft greater than dB may be obtained by adjusting the
value obtained by 5C-3-A6/7.3.2(c)i) for the added buoyancy due to the increase in draft,
subject to 5C-3-A6/7.3.2(d).
7.3.2(d) The final minimum required mass in the draft range in 5C-3-A6/7.3.2(b)ii),
5C-3-A6/7.3.2(c)ii) or, where applicable, 5C-3-A6/7.3.3(b)ii) is the least of the two (or three).
7.3.2(e)
i) Any two adjacent cargo holds are to be capable of carrying at least MFull in each cargo
hold with fuel oil tanks in double bottom in way of each cargo hold, if any, 100% full and
ballast water tanks in the double bottom in way of each cargo hold empty, at d.
ii) The maximum allowable hold mass for any two adjacent holds at a draft less than d may
be obtained by adjusting the value obtained by 5C-3-A6/7.3.2(e)i) for the loss of buoyancy
due to the decrease in draft.
7.3.2(f)
i) Any two adjacent cargo holds are to be capable of being immersed to d with a mass not
exceeding 0.5MH in each cargo hold and with all double bottom tanks in way of each
cargo hold empty.
ii) The minimum required hold mass for any two adjacent holds at a draft less than d may be
obtained by adjusting the value obtained by 5C-3-A6/7.3.2(f)i) for the loss of buoyancy
due to the decrease in draft, if that is less than that obtained from 5C-3-A6/7.3.3(d)ii).
7.3.3 Conditions for all Ships without Additional Notation (no MP)
All bulk carriers are to be designed for partial loading conditions in 5C-3-A6/7.3.3(a) through
5C-3-A6/7.3.3(d), unless the additional notation (no MP) is desired.
7.3.3(a)
i) Any cargo hold is to be capable of carrying at least MFull with fuel oil tanks in double
bottom in way of the cargo hold, if any, 100% full and ballast water tanks in the double
bottom in way of the cargo hold empty, at 0.67d.
ii) The maximum allowable hold mass for a draft less than 0.67d may be obtained by adjusting
the value obtained by 5C-3-A6/7.3.3(a)i) for the loss of buoyancy due to the decrease in draft.
7.3.3(b)
i) Any cargo hold is to be capable of being immersed to 0.83d with the hold and all double
bottom tanks in way of the cargo hold empty.
ii) The minimum required hold mass for a draft greater than 0.83d may be obtained by
adjusting the value obtained by 5C-3-A6/7.3.3(b)i) for the added buoyancy due to the
increase in draft, subject to 5C-3-A6/7.3.2(d).
7.3.3(c)
i) Any two adjacent cargo holds are to be capable of carrying at least MFull with fuel oil
tanks in double bottom in way of the cargo holds, if any, 100% full and ballast water
tanks in the double bottom in way of the cargo hold empty, at 0.67d. This requirement
regarding the mass of cargo and fuel oil in double bottom tanks in way of the cargo hold
applies also to the condition where the adjacent hold is fitted with ballast, if applicable.
ii) The maximum allowable hold mass for any two adjacent holds at a draft less than 0.67d
may be obtained by adjusting the value obtained by 5C-3-A6/7.3.3(c)i) for the loss of
buoyancy due to the decrease in draft.

554 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 6 Harmonized System of Notations and Corresponding Design Loading Conditions for
Bulk Carriers 5C-3-A6

7.3.3(d)
i) Any two adjacent cargo holds are to be capable of being immersed to 0.75d, with the
cargo holds and all double bottom tanks in way of the cargo holds empty.
ii) The minimum required hold mass for any two adjacent holds at a draft greater than 0.75d may
be obtained by adjusting the value obtained by 5C-3-A6/7.3.3(d)i) for the added buoyancy
due to the increase in draft, if that is less than that obtained from 5C-3-A6/7.3.2(f)ii).
7.3.4 Additional Conditions Applicable for BC-A Notation
7.3.4(a) Cargo holds, which are intended to be empty at d, are to be capable of being empty with
all double bottom tanks in way of the cargo hold also empty.
7.3.4(b)
i) Cargo holds, which are intended to be loaded with high density cargo, are to be capable of
carrying at least MHD + 0.1MH in each cargo hold, with fuel oil tanks in the double bottom
in way of the cargo holds, if any, 100% full and ballast water tanks in the double bottom
empty in way of the cargo hold, at d.
ii) In operation the maximum allowable cargo mass, with the contents of double bottom
tanks as described above, is to be limited to MHD for draft above d1, where d1 is the draft
corresponding to maximum summer draft d after adjustment for 0.1MH.
iii) The maximum allowable hold mass for a draft less than d1 may be obtained by adjusting
the value obtained by 5C-3-A6/7.3.4(b)i) for the loss of buoyancy due to the decrease in draft.
7.3.4(c)
i) Any two adjacent cargo holds which according to a design loading condition may be
loaded with the adjacent third and fourth holds (or any other spaces) empty, are to be capable
of carrying 10% of MH in each hold in addition to the maximum cargo mass according to
that design loading condition, with fuel oil tanks in the double bottom in way of the cargo
holds, if any, 100% full and ballast water tanks in the double bottom in way of the cargo
holds empty, at d.
ii) In operation the maximum allowable mass in each hold, with the contents of double
bottom tanks as described above, is to be limited to the maximum cargo mass according
to that design loading condition for draft above d1 where d1 is the draft corresponding to
maximum summer draft d after adjustment for 0.1MH.
iii) The maximum allowable hold mass for any two adjacent holds at a draft less than d1 may
be obtained by adjusting the value obtained by 5C-3-A6/7.3.4(c)i) for the loss of buoyancy
due to the decreased draft.
7.3.5 Additional Conditions Applicable for At-sea Ballast Holds
7.3.5(a) Cargo holds, including hatchways, which are designed as ballast water holds at sea, are
to be capable of being 100% full of ballast water with all double bottom tanks in way of the cargo
hold being 100% full at any heavy ballast draft. For at-sea ballast holds adjacent to topside wing,
hopper and double bottom tanks, the local strength is to be satisfactory with the hold full with
ballast and the topside wing, hopper and double bottom tanks empty.
7.3.6 Additional Conditions Applicable during Loading and Unloading in Harbor
7.3.6(a)
i) In harbor condition, any single cargo hold is to be capable of holding, at 0.67d, at least the
maximum allowable seagoing mass (MMAX).
where:
MMAX = MHD + MDBF for loaded hold on BC-A
= MFULL+ MDBF for all other holds
MDBF = mass of fuel oil in double bottom tank

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Part 5C Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 6 Harmonized System of Notations and Corresponding Design Loading Conditions for
Bulk Carriers 5C-3-A6

ii) The maximum allowable hold mass for a draft less than 0.67d may be obtained by
adjusting the value obtained by 5C-3-A6/7.3.6(a)i) for the loss of buoyancy due to the
decrease in draft, subject to 5C-3-A6/7.3.6(c)i).
7.3.6(b)
i) In harbor condition, any two adjacent cargo holds are to be capable of carrying at least
MFull, with fuel oil tanks in the double bottom in way of the cargo holds, if any, 100% full
and ballast water tanks in the double bottom in way of the cargo holds empty, at 0.67d.
ii) The maximum allowable hold mass for any two adjacent holds at a draft less than 0.67d
may be obtained by adjusting the value obtained by 5C-3-A6/7.3.6(b)i) for the loss of
buoyancy due to the decrease in draft.
7.3.6(c)
i) The maximum allowable cargo mass in harbor condition, at a draft less than d [see
5C-3-A6/7.3.2(a)ii)], d1 (see 5C-3-A6/7.3.4(b)iii) et al) or 0.67d (see 5C-3-A6/7.3.3(a)ii)
et al), may be obtained by adding 0.15MHD for loaded holds on BC-A or 0.15MFULL for all
other holds to the allowable seagoing mass at that draft where it is greater than the
allowable mass obtained by 5C-3-A6/7.3.6(a), subject to the maximum of MMAX.
ii) Likewise, the minimum required mass in harbor condition, at a draft greater than dB [see
5C-3-A6/7.3.2(c)ii)], 0.83d [see 5C-3-A6/7.3.3(b)ii)] or 0.75d [see 5C-3-A6/7.3.3(d)ii)]
may be obtained by subtracting 0.15MHD for loaded holds on BC-A or 0.15MFULL for all
other holds from the allowable seagoing cargo mass at that draft, subject to the minimum
of MMIN, where MMIN is the minimum required seagoing cargo mass at a draft less than
those values mentioned.
7.3.7 Hold Mass Curves
7.3.7(a) Hold mass curves, prepared based on the design loading criteria for local strength in
5C-3-A6/7.3.2 to 5C-3-A6/7.3.6 above, and showing maximum allowable and minimum required
mass as a function of draft, are to be included in the loading manual and the loading instrument.
The design loading criteria in 5C-3-A6/7.3.5 is not be used to prepare hold mass curves of dry
cargo for a hold adapted for the carriage of water ballast.
7.3.7(b) Hold mass curves are to be prepared for each single hold, as well as for any two adjacent
holds, each further divided into sea-going condition and during loading and unloading in harbor.
[See 3-2-A3/5.1.1(c) and 3-2-A3/5.1.1(d)].
7.3.7(c) At drafts other than those specified in the design loading conditions above, the maximum
allowable and minimum required mass is to be adjusted for the change in the buoyancy acting on
the bottom as specified in the respective paragraphs.
7.3.7(d) Each hold mass curve is to contain instructions for use with varying amount of contents
in double bottom tanks.
7.3.8 Quick Reference to 5C-3-A6/7.3
A quick reference to local loading conditions in 5C-3-A6/7.3 (except for ballast hold in 5C-3-A6/7.3.5)
is shown in 5C-3-A6/Tables 2A and 2B. For detailed requirements, the respective text is to be
referred to.

556 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
 TABLE 2A
Part

Cargo Hold Loads (5C-3-A6/7.3) – Single Hold

notation L or E Cond’n Maximum Allowable Minimum Required
summer draft (d) shallower draft @ summer draft shallower draft @
5.2.1 (7.3.2a): MFULL + MDBF 5.4.2 (7.3.4b): MHD + MDBF d1 5.2.2 (7.3.2b): 0.5MH 5.2.3 (7.3.2c): 0 dB
at sea
5.4.2 (7.3.4b): MHD + (0.1MH) + MDBF *5.3.1 (7.3.3a): MFULL + MDBF *0.67d *5.3.2 (7.3.3b): 0 *0.83d
Loaded
No MP (at sea) - * marked req’t (at sea) - * marked req’t
Hold
5.6.1 (7.3.6a): MMAX = MHD(MFULL) + MDBF 0.67d 5.6.3 (7.3.6c): (min @sea) >dB, 0.83d,
harbor
BC-A 5.6.3 (7.3.6c): (max @sea) = 0.15MMAX <d,d1,0.67d – 0.15MMIN 0.75d
at sea 5.2.1 (7.3.2a): MFULL + MDBF *5.3.1 (7.3.3a): MFULL + MDBF *0.67d 5.4.1 (7.3.4a): 0
Bulk Carriers

Empty No MP (at sea) - * marked req’t

Hold 5.6.1 (7.3.6a): MMAX = MHD(MFULL) + MDBF 0.67d
harbor
5.6.3 (7.3.6c): (max @sea) = 0.15MMAX <d,d1,0.67d
5.2.1 (7.3.2a): MFULL + MDBF *5.3.1 (7.3.3a): MFULL + MDBF *0.67d 5.2.2(7.3.2b): 0.5MH 5.2.3 (7.3.2c): 0 dB
at sea
5C Specific Vessel Types

*5.3.2 (7.3.3b): 0 *0.83d

BC-B No MP (at sea) - * marked req’t (at sea) - * marked req’t
5.6.1 (7.3.6a): MMAX = MHD(MFULL) + MDBF 0.67d 5.6.3 (7.3.6c): (min @sea) >dB, 0.83d,
harbor
5.6.3 (7.3.6c): (max @sea) = 0.15MMAX <d,d1,0.67d – 0.15MMIN 0.75d
5.2.1 (7.3.2a): MFULL + MDBF *5.3.1 (7.3.3a): MFULL + MDBF *0.67d 5.2.2(7.3.2b): 0.5MH 5.2.3 (7.3.2c): 0 dB
at sea
*5.3.2 (7.3.3b): 0 *0.83d
BC-C No MP (at sea) - * marked req’t (at sea) - * marked req’t
5.6.1 (7.3.6a): MMAX = MHD(MFULL) + MDBF 0.67d 5.6.3 (7.3.6c): (min @sea) >dB, 0.83d,
harbor
5.6.3 (7.3.6c): (max @sea) = 0.15MMAX <d,d1,0.67d – 0.15MMIN 0.75d

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

TABLE 2B
Cargo Hold Loads (5C-3-A6/7.3) (loads in each hold shown)
notation L or E Cond’n Maximum Allowable Minimum Required
summer draft (d) shallower draft @ summer draft shallower draft @
at sea 5.4.3 (7.3.4c): MHD + (0.1MH) + MDBF *5.3.3 (7.3.3c): MFULL + MDBF *0.67d None, (7.3.2f): 0.5MH *5.3.4 (7.3.3d): 0 *0.75d
Two
None, (7.3.2e): MFULL + MDBF
Loaded
No MP (at sea) - * marked req’t (at sea) - * marked req’t
Holds
BC-A harbor 5.6.2 (7.3.6b): MFULL + MDBF 0.67d
at sea None, (7.3.2e): MFULL + MDBF *5.3.3 (7.3.3c): MFULL + MDBF *0.67d *5.3.4 (7.3.3d): 0 *0.75d
All
No MP (at sea) - * marked req’t (at sea) - * marked req’t
Holds
harbor 5.6.2 (7.3.6b): MFULL + MDBF 0.67d
at sea None, (7.3.2e): MFULL + MDBF *5.3.3 (7.3.3c): MFULL + MDBF *0.67d *5.3.4 (7.3.3d): 0 *0.75d
BC-B No MP (at sea) - * marked req’t (at sea) - * marked req’t
harbor 5.6.2 (7.3.6b): MFULL + MDBF 0.67d
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)

at sea None, (7.3.2e): MFULL + MDBF *5.3.3 (7.3.3c): MFULL + MDBF *0.67d *5.3.4 (7.3.3d): 0 *0.75d
BC-C No MP (at sea) - * marked req’t (at sea) - * marked req’t
Appendix 6 Harmonized System of Notations and Corresponding Design Loading Conditions for

harbor 5.6.2 (7.3.6b): MFULL + MDBF 0.67d

557
5C-3-A6
PART Appendix 7: Guide for Hull Girder Ultimate Strength Assessment of Bulk Carriers

5C
CHAPTER 3 Vessels Intended to Carry Ore or Bulk Cargoes
(150 meters (492 feet) or more in Length)

APPENDIX 7 Guide for Hull Girder Ultimate Strength

Assessment of Bulk Carriers (2010)

1 General
The hull structure may be verified for compliance with the hull girder ultimate strength requirements using
this Appendix. For vessels that are to be designed for compliance with the Common Structural Rules
(CSR), the specific hull girder ultimate strength requirements in Part 5B of the Steel Vessel Rules are to be
applied.
In general, the requirements are applicable to the hull structure within 0.4L amidships in sea-going
conditions. For vessels that are subject to higher bending moment, the hull girder ultimate strength in the
forebody and aft body regions is also to be verified.

3 Vertical Hull Girder Ultimate Limit State

The vertical hull girder ultimate bending capacity is to satisfy the following limit state equation:
MU
γSMsw + γWMw ≤
γR
where
Msw = still water bending moment, in kN-m (tf-m), in accordance with 3-2-1/3.3
Mw = maximum wave-induced bending moment, in kN-m (tf-m), in accordance with
3-2-1/3.5.1
MU = vertical hull girder ultimate bending capacity, in kN-m (tf-m), as defined in 5C-3-A7/5

γS = 1.0 partial safety factor for the still water bending moment
γw = 1.20 partial safety factor for the vertical wave bending moment covering
environmental and wave load prediction uncertainties
γR = 1.10 partial safety factor for the vertical hull girder bending capacity covering
material, geometric and strength prediction uncertainties
In general, for vessels where the hull girder ultimate strength is evaluated with gross scantlings, γR is to be
taken as 1.25.

558 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5 Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 7 Hull Girder Ultimate Strength Assessment of Bulk Carriers 5-3-A7

5 Hull Girder Ultimate Bending Moment Capacity

5.1 General
The ultimate bending moment capacities of a hull girder section, in hogging and sagging conditions, are
defined as the maximum values (positive MUH, negative MUS) on the static nonlinear bending moment-
curvature relationship M-κ. See 5C-3-A7/Figure 1. The curve represents the progressive collapse behavior
of the hull girder under vertical bending. Hull girder failure is controlled by buckling, ultimate strength and
yielding of longitudinal structural elements.

FIGURE 1
Bending Moment – Curvature Curve M-κ (2010)
M
Hogging Condition
MUH

MUS
Sagging Condition

The curvature of the critical inter-frame section,κ, is defined as:

θ -1
κ= m
l
where:
θ = relative angle rotation of the two neighboring cross-sections at transverse frame
positions
l = transverse frame spacing in m, i.e., span of longitudinals
The method for calculating the ultimate hull girder capacity is to identify the critical failure modes of all
main longitudinal structural elements.
Longitudinal structural members compressed beyond their buckling limit have reduced load carrying
capacity. All relevant failure modes for individual structural elements, such as plate buckling, torsional
stiffener buckling, stiffener web buckling, lateral or global stiffener buckling and their interactions, are to
be considered in order to identify the weakest inter-frame failure mode.
The effects of shear force, torsional loading, horizontal bending moment and lateral pressure are neglected.

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Part 5 Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 7 Hull Girder Ultimate Strength Assessment of Bulk Carriers 5-3-A7

5.3 Physical Parameters

For the purpose of describing the calculation procedure in a concise manner, the physical parameters and
units used in the calculation procedure are given below.
5.3.1 Hull Girder Load and Cross Section Properties
Mi = hull girder bending moment, in kN-m (tf-m)
Fi = hull girder longitudinal force, in kN (tf)
Iv = hull girder moment of inertia, in m4

SM = hull girder section modulus, in m3

SMdk = elastic hull girder section modulus at deck at side, in m3

SMkl = elastic hull girder section modulus at bottom, in m3

κ = curvature of the ship cross section, in m-1

zj = distance from baseline, in m

5.3.2 Material Properties

σyd = specified minimum yield stress of the material, in N/cm2 (kgf/cm2)

E = Young’s modulus for steel, 2.06 × 107 N/cm2 (2.1 × 106 kgf/cm2)
ν = Poisson’s ratio, may be taken as 0.3 for steel
Φ = edge function as defined in 5C-3-A7/5.9.2
ε = relative strain defined in 5C-3-A7/5.9.2
5.3.3 Stiffener Sectional Properties
The properties of a longitudinal’s cross section are shown in 5C-3-A7/Figure 2.
As = sectional area of the longitudinal or stiffener, excluding the associated plating, in cm2
b1 = smaller outstanding dimension of flange with respect to centerline of web, in cm
bf = total width of the flange/face plate, in cm
dw = depth of the web, in cm
tp = net thickness of the plating, in cm
tf = net thickness of the flange/face plate, in cm
tw = net thickness of the web, in cm
xo = distance between centroid of the stiffener and centerline of the web plate, in cm
yo = distance between the centroid of the stiffener and the attached plate, in cm

560 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5 Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 7 Hull Girder Ultimate Strength Assessment of Bulk Carriers 5-3-A7

FIGURE 2
Dimensions and Properties of Stiffeners (2010)
bf

b2 b1

tf

xo
CENTROID OF WEB
AND FACE PLATE
(NET SECTION)

tw

yo
dw

tp

be

5.5 Calculation Procedure

The ultimate hull girder bending moment capacity MU is defined as the peak value of the curve with
vertical bending moment M versus the curvature κ of the ship cross section as shown in 5C-3-A7/Figure 1.
The curve M-κ is obtained by means of an incremental-iterative approach. The steps involved in the
procedure are given below.
The bending moment Mi which acts on the hull girder transverse section due to the imposed curvature κi is
calculated for each step of the incremental procedure. This imposed curvature corresponds to an angle of
rotation of the hull girder transverse section about its effective horizontal neutral axis, which induces an
axial strain ε in each hull structural element.
The stress σ induced in each structural element by the strain ε is obtained from the stress-strain curve σ-ε
of the element, which takes into account the behavior of the structural element in the nonlinear elasto-
plastic domain.
The force in each structural element is obtained from its area times the stress and these forces are summed
to derive the total axial force on the transverse section. Note the element area is taken as the total net area
of the structural element. This total force may not be zero as the effective neutral axis may have moved due
to the nonlinear response. Hence, it is necessary to adjust the neutral axis position, recalculate the element
strains, forces and total sectional force, and iterate until the total force is zero.
Once the position of the new neutral axis is known, then the correct stress distribution in the structural
elements is obtained. The bending moment Mi about the new neutral axis due to the imposed curvature κi is
then obtained by summing the moment contribution given by the force in each structural element.

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 7 Hull Girder Ultimate Strength Assessment of Bulk Carriers 5-3-A7

The main steps of the incremental-iterative approach are summarized as follows:

Step 1 Divide the hull girder transverse section into structural elements, (i.e., longitudinal stiffened panels
(one stiffener per element), hard corners and transversely stiffened panels), see 5C-3-A7/5.7.
Step 2 Derive the stress-strain curves (also known as the load-end shortening curves) for all structural
elements, see 5C-3-A7/5.9.
Step 3 Derive the expected maximum required curvature, κF. The curvature step size Δκ is to be taken as
κF/300. The curvature for the first step, κ1 is to be taken as Δκ.
Derive the neutral axis zNA-i for the first incremental step (i = 1) with the value of the elastic hull girder
section modulus, see 3-2-1/9.
Step 4 For each element (index j), calculate the strain εij = κi(zj – zNA-i) corresponding to κi, the corresponding
stress σj , and hence the force in the element σj Aj. The stress σj corresponding to the element strain εij is to
be taken as the minimum stress value from all applicable stress-strain curves σ-ε for that element.
Step 5 Determine the new neutral axis position zNA-i by checking the longitudinal force equilibrium over
the whole transverse section. Hence, adjust zNA-i until:
Fi = 10-3 ΔAjσj = 0
Note σj is positive for elements under compression and negative for elements under tension. Repeat from
Step 4 until equilibrium is satisfied. Equilibrium is satisfied when the change in neutral axis position is less
than 0.0001 m.
Step 6 Calculate the corresponding moment by summing the force contributions of all elements as follows:

Mi = 10-3 ∑σ j Aj (z j − z NA−i )
Step 7 Increase the curvature by Δκ, use the current neutral axis position as the initial value for the next
curvature increment and repeat from Step 4 until the maximum required curvature is reached. The ultimate
capacity is the peak value Mu from the M-κ curve. If the peak does not occur in the curve, then κF is to be
increased until the peak is reached.
The expected maximum required curvature κF is to be taken as:
(
max SM dk σ yd , SM kl σ yd )
κF = 3
EI v

5.7 Assumptions and Modeling of the Hull Girder Cross-section

In applying the procedure described in this Appendix, the following assumptions are to be made:
i) The ultimate strength is calculated at a hull girder transverse section between two adjacent transverse
webs.
ii) The hull girder transverse section remains plane during each curvature increment.
iii) The material properties of steel are assumed to be elastic, perfectly plastic.
iv) The hull girder transverse section can be divided into a set of elements which act independently of
each other.
v) The elements making up the hull girder transverse section are:
• Longitudinal stiffeners with attached plating, with structural behavior given in 5C-3-A7/5.9.2,
5C-3-A7/5.9.3, 5C-3-A7/5.9.4, 5C-3-A7/5.9.5 and 5C-3-A7/5.9.6
• Transversely stiffened plate panels, with structural behavior given in 5C-3-A7/5.9.7
• Hard corners, as defined below, with structural behavior given in 5C-3-A7/5.9.1

562 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5 Specific Vessel Types
Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 7 Hull Girder Ultimate Strength Assessment of Bulk Carriers 5-3-A7

vi) The following structural areas are to be defined as hard corners:

• The plating area adjacent to intersecting plates
• The plating area adjacent to knuckles in the plating with an angle greater than 30 degrees.
• Plating comprising rounded gunwales
An illustration of hard corner definition for girders on longitudinal bulkheads is given in
5C-3-A7/Figure 3.
vii) The size and modeling of hard corner elements is to be as follows:
• It is to be assumed that the hard corner extends up to s/2 from the plate intersection for
longitudinally stiffened plate, where s is the stiffener spacing
• It is to be assumed that the hard corner extends up to 20tgrs from the plate intersection for
transversely stiffened plates, where tgrs is the gross plate thickness.
Note: For transversely stiffened plate, the effective breadth of plate for the load shortening portion of the stress-strain
curve is to be taken as the full plate breadth, i.e., to the intersection of other plates – not from the end of the hard
corner. The area is to be calculated using the breadth between the intersecting plates.

FIGURE 3
Example of Defining Structural Elements (2010)
a) Example showing side shell, inner side and deck

Longitudinal
stiffener elements
Hard corner
elements

b) Example showing girder on longitudinal bulkhead

Longitudinal
stiffener elements

Hard corner
element

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 7 Hull Girder Ultimate Strength Assessment of Bulk Carriers 5-3-A7

5.9 Stress-strain Curves σ-ε (or Load-end Shortening Curves)

5.9.1 Hard Corners
Hard corners are sturdier elements which are assumed to buckle and fail in an elastic, perfectly
plastic manner. The relevant stress strain curve σ-ε is to be obtained for lengthened and shortened
hard corners according to 5C-3-A7/5.9.2.
5.9.2 Elasto-Plastic Failure of Structural Elements
The equation describing the stress-strain curve σ-ε of the elasto-plastic failure of structural
elements is to be obtained from the following formula, valid for both positive (compression or
shortening) of hard corners and negative (tension or lengthening) strains of all elements (see
5C-3-A7/Figure 4):
σ = Φ σyd kN/cm2 (kgf/cm2)
where
Φ = edge function
= –1 for ε < –1
= ε for –1 < ε < 1
= 1 for ε > 1
ε = relative strain
εE
=
ε yd

εE = element strain
εyd = strain corresponding to yield stress in the element
σ yd
=
E
Note: The signs of the stresses and strains in this Appendix are opposite to those in the rest of the Rules.

FIGURE 4
Example of Stress Strain Curves σ-ε (2010)
a) Stress strain curve σ-ε for elastic, perfectly plastic failure of a hard corner
σ

σyd

compression or
shortening

tension or
lengthening

−σyd

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 7 Hull Girder Ultimate Strength Assessment of Bulk Carriers 5-3-A7

FIGURE 4 (continued)
Example of Stress Strain Curves σ-ε (2010)
b) Typical stress strain curve σ-ε for elasto-plastic failure of a stiffener
σ

σyd

compression or
shortening
ε

tension or
lengthening

−σyd

5.9.3 Beam Column Buckling

The equation describing the shortening portion of the stress strain curve σCR1-ε for the beam
column buckling of stiffeners is to be obtained from the following formula:
⎛ As + beff − p t p ⎞
σ CR1 = Φσ C1 ⎜ ⎟ kN/cm2 (kgf/cm2)
⎜ As + st p ⎟
⎝ ⎠
where
σC1 = critical stress, in kgf/cm2 (kgf/cm2)

σ E1 σ yd
= for σE1 ≤ ε
ε 2
⎛ σ yd ε ⎞ σ yd
= σ yd ⎜⎜1 − ⎟ for σE1 > ε
⎝ 4σ E1 ⎟⎠ 2

σE1 = Euler column buckling stress, in kgf/cm2 (kgf/cm2)

IE
= π 2E
AE l 2

l = unsupported span of the longitudinal, in cm

s = plate breadth taken as the spacing between the stiffeners, in cm
IE = net moment of inertia of stiffeners, in cm4, with attached plating of width beff-s
beff-s = effective width, in cm, of the attached plating for the stiffener

s
= for βp > 1.0
βp

= s for βp ≤ 1.0

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Appendix 7 Hull Girder Ultimate Strength Assessment of Bulk Carriers 5-3-A7

s εσ yd
βp =
tp E

AE = net area of stiffeners, in cm2, with attached plating of width beff-p

beff-p = effective width, in cm, of the plating

⎛ 2.25 1.25 ⎞
= ⎜ − 2 ⎟s for βp > 1.25
⎜ βp β p ⎟⎠
⎝
= s for βp ≤ 1.25

5.9.4 Torsional Buckling of Stiffeners

The equation describing the shortening portion of the stress-strain curve σCR2-ε for the lateral-
flexural buckling of stiffeners is to be obtained according to the following formula:
⎛ As σ C 2 + st p σ CP ⎞
σ CR 2 = Φ⎜ ⎟ kN/cm2 (kgf/cm2)
⎜ As + st p ⎟
⎝ ⎠
where
σC2 = critical stress

σ E2 σ yd
= for σE2 ≤ ε
ε 2
⎛ σ yd ε ⎞ σ yd
= σ yd ⎜⎜1 − ⎟ for σE2 > ε
⎝ 4σ E 2 ⎟⎠ 2

σCP = ultimate strength of the attached plating for the stiffener

⎛ 2.25 1.25 ⎞
= ⎜ − 2 ⎟σ yd for βp > 1.25
⎜ βp β p ⎟⎠
⎝
= σyd for βp ≤ 1.25

βp = coefficient defined in 5C-3-A7/5.9.3

σE2 = Euler torsional buckling stress, in kN/cm2 (kgf/cm2), equal to reference stress
for torsional buckling σET
σET = E[K/2.6 + (nπ/l)2Γ + Co(l/nπ)2/E]/Io[1 + Co(l/nπ)2/Io fcL]
K = St. Venant torsion constant for the longitudinal’s cross section, excluding the
associated plating

= [b t f
3
f ]
+ d w t w3 / 3

Io = polar moment of inertia of the longitudinal, excluding the associated plating,

about the toe (intersection of web and plating)

= Ix + mIy + As x o2 + y o2 ( ) in cm4
Ix, Iy = moment of inertia of the longitudinal about the x- and y-axis, respectively,
through the centroid of the longitudinal, excluding the plating (x-axis
perpendicular to the web), in cm4
m = 1.0 − u(0.7 − 0.1dw/bf)

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Chapter 3 Vessels Intended to Carry Ore or Bulk Cargoes (150 m (492 ft) or more in Length)
Appendix 7 Hull Girder Ultimate Strength Assessment of Bulk Carriers 5-3-A7

u = unsymmetry factor
= 1 − 2b1/bf

Co = E t 3p /3s

Γ = warping constant

≅ mIyf d w2 + d w3 t w3 /36

Iyf = tf b 3f (1.0 + 3.0 u2dwtw/As)/12

fcL = critical buckling stress for the associated plating, corresponding to n-half
waves
= π2E(n/α + α/n)2(tp/s)2/12(1 − ν2)
α = l/s
l = unsupported span of the longitudinal, in cm
s = plate breadth taken as the spacing between the stiffeners, in cm
n = number of half-wave which yield a smallest σET

5.9.5 Web Local Buckling of Stiffeners with Flanged Profiles

The equation describing the shortening portion of the stress strain curve σCR3-ε for the web local
buckling of flanged stiffeners is to be obtained from the following formula:
⎛ beff − p t p + d w−eff t w + b f t f ⎞
σ CR 3 = Φσ yd ⎜ ⎟ kN/cm2 (kgf/cm2)
⎜ st p + d w t w + b f t f ⎟
⎝ ⎠
where
s = plate breadth taken as the spacing between the stiffeners, in cm
beff-p = effective width of the attached plating in cm, defined in 5C-3-A7/5.9.3
dw-eff = effective depth of the web, in cm

⎛ 2.25 1.25 ⎞
= ⎜ − 2 ⎟d w for βw > 1.25
⎜ β
⎝ w β w ⎟⎠
= dw for βw ≤ 1.25

dw εσ yd
βw =
tw E

5.9.6 Local Buckling of Flat Bar Stiffeners

The equation describing the shortening portion of the stress-strain curve σCR4-ε for the web local
buckling of flat bar stiffeners is to be obtained from the following formula:
⎛ As σ C 4 + st p σ CP ⎞
σ CR 4 = Φ⎜ ⎟ kN/cm2 (kgf/cm2)
⎜ As + st p ⎟
⎝ ⎠
where
σCP = ultimate strength of the attached plating, in kN/cm2 (kgf/cm2)

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Appendix 7 Hull Girder Ultimate Strength Assessment of Bulk Carriers 5-3-A7

σC4 = critical stress, in kN/cm2 (kgf/cm2)

σ E4 σ yd
= for σE4 ≤ ε
ε 2
⎛ σ yd ε ⎞ σ yd
= σ yd ⎜⎜1 − ⎟ for σE4 > ε
⎝ 4σ E 4 ⎟⎠ 2

σE4 = Euler buckling stress

2
0.44π 2 E ⎛ t w ⎞
⎜ ⎟
=
( )
12 1 − ν 2 ⎜⎝ d w ⎟
⎠

5.9.7 Buckling of Transversely Stiffened Plate Panels

The equation describing the shortening portion of the stress-strain curve σCR5-ε for the buckling of
transversely stiffened panels is to be obtained from the following formula:
⎧ ⎡ ⎛ 2.25 1.25 ⎞ ⎞ ⎤
2
⎪σ ⎢ s ⎛ s ⎞⎛ 1
⎪ yd ⎜ ⎟
− 2 + 0.115⎜1 − ⎜
⎟ 1+ ⎟ ⎥
σ CR 5 = min ⎨ ⎢ l stf ⎜ βp βp ⎠⎟ ⎜ l ⎟⎜
stf ⎠⎝
2 ⎟ ⎥ kN/cm2 (kgf/cm2)
βp ⎠
⎢⎣ ⎝ ⎝ ⎥⎦
⎪
⎪⎩σ yd Φ

where
βp = coefficient defined in 5C-3-A7/5.9.3
s = plate breadth taken as the spacing between the stiffeners, in cm
lstf = span of stiffener equal to spacing between primary support members, in cm

568 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
PART Chapter 4: Vessels Intended to Carry Ore or Bulk Cargoes (Under 150 meters (492 feet) in Length)

5C
CHAPTER 4 Vessels Intended to Carry Ore or Bulk Cargoes
(Under 150 meters (492 feet) in Length)

CONTENTS
SECTION 1 Introduction ........................................................................................ 571
1 General ...........................................................................................571
1.1 Classification ............................................................................... 571
1.3 Application................................................................................... 571
1.5 Arrangement................................................................................ 571
1.7 Scantlings.................................................................................... 571
1.9 Higher-strength Materials ............................................................ 571
1.11 Protection of Structure................................................................. 572
3 Carriage of Oil Cargoes ..................................................................572
3.1 General........................................................................................ 572
3.3 Gas Freeing................................................................................. 572
3.5 Slop Tanks .................................................................................. 572
5 Special Requirements for Deep Loading ........................................572
7 Forecastle .......................................................................................572
7.1 General........................................................................................ 572
7.3 Arrangements.............................................................................. 573
7.5 Dimensions.................................................................................. 573
7.7 Structural Arrangements and Scantlings ..................................... 573

FIGURE 1 .......................................................................................573

SECTION 2 Hull Structure ..................................................................................... 574

1 Hull Girder Strength ........................................................................574
1.1 Normal-strength Standard ........................................................... 574
1.3 Hull Girder Shear and Bending Moments .................................... 574
1.5 Loading Guidance ....................................................................... 574
3 Transverse Bulkheads in Hold........................................................574
5 Shell Plating ....................................................................................574
7 Deck Plating....................................................................................574
9 Double-bottom and Tank Structure.................................................575
9.1 General........................................................................................ 575
9.3 Floors and Transverses............................................................... 575
9.5 Bottom Longitudinals and Side Tank Framing............................. 575
9.7 Inner-bottom Longitudinals .......................................................... 575
9.9 Inner-bottom Plating .................................................................... 576
9.11 Tank Bulkhead Plating ................................................................ 576

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 569
 9.13 Lower Wing Tank Stiffeners.........................................................576
9.15 Transverse Webs.........................................................................577
9.17 Carriage of Water Ballast or Liquid Cargoes in Cargo Holds.......577
11 Framing ...........................................................................................577
11.1 Transverse Hold Framing ............................................................577
11.3 Upper Wing Tank Framing...........................................................579
11.5 Transverse Webs.........................................................................579
13 Cargo Hold Hatch Covers, Coamings and Closing
Arrangements..................................................................................579
13.1 General........................................................................................579
13.3 Hatch Cover Design Pressures ...................................................579
15 Testing ............................................................................................580
17 Self-unloading Gear ........................................................................580

FIGURE 1 Length of Hold Frame ...........................................................581

FIGURE 2.....................................................................................................582
FIGURE 3.....................................................................................................582
FIGURE 4.....................................................................................................583

SECTION 3 Cargo Safety and Vessel Systems .................................................... 584

570 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
PART Section 1: Introduction

5C
CHAPTER 4 Vessels Intended to Carry Ore or Bulk Cargoes
(Under 150 meters (492 feet) in Length)

SECTION 1 Introduction
Note: Vessels with Freeboard Length Lf, as defined in 3-1-1/3.3, of 150 m (492 ft) or more are to comply with SOLAS
Chapter XII. Part 5C, Chapter 3 of these Rules may be used for that purpose.

1 General

1.1 Classification
In accordance with 1-1-3/3, the classification À A1 Bulk Carrier or À A1 Ore Carrier is to be assigned
to vessels designed for the carriage of bulk cargoes, or ore cargoes, and built to the requirements of this
section and other relevant sections of the Rules. Where the vessel has been specially reinforced for the
carriage of heavy-density cargoes, special loading arrangements, or both, it will be distinguished in the
Record with a notation describing the special arrangements. Full particulars of the loading conditions and
the maximum density of the cargoes to be provided for are to be given on the basic design drawings.

1.3 Application
These requirements are intended to apply to vessels having machinery aft, one deck and a complete or
partial double bottom. They are intended to apply to vessels generally of welded construction, of usual
form and having proportions in accordance with 3-1-2/7. They are applicable to vessels having
longitudinal framing and that have topside tanks and side tanks, or two continuous longitudinal bulkheads.
Transverse side framing will also be acceptable. These Rules are also intended to apply to other vessels of
similar type and arrangement.

1.5 Arrangement
Watertight and strength bulkheads, in accordance with Section 3-2-9, are to be provided. Where this is
impracticable, the transverse strength and stiffness of the hull is to be effectively maintained by deep webs
or partial bulkheads. Where it is intended to carry liquid in any of the spaces, additional bulkheads or
swash bulkheads may be required. Tank bulkheads are to be in accordance with the requirements of
Section 3-2-10 or Section 5C-2-2, as appropriate. The depth of double bottom at the centerline is not to be
less than the height for center girders, as obtained from Section 3-2-4. Tanks forward of the collision
bulkhead are not to be arranged for the carriage of oil or other liquid substances that are flammable.

1.7 Scantlings
It is recommended that compliance with the following requirements be accomplished through detailed
investigation of the magnitude and distribution of the imposed longitudinal and transverse forces by using
an acceptable method of engineering analysis. Where the structural members are highly stressed, their
stability characteristics are to be investigated. In any case, the following paragraphs are to be used as a
guide in determining scantlings.

1.9 Higher-strength Materials

In general, applications of higher-strength materials for vessels intended to carry ore or bulk cargoes are to
meet the requirements of this chapter, but may be modified generally in accordance with the following
sections: Section 3-2-4 for deep longitudinal members, Section 3-2-4 and Section 3-2-7 for longitudinals,
Section 3-2-10 for bulkhead plating, Section 3-2-2 for shell plating and Section 3-2-3 for deck plating

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Chapter 4 Vessels Intended to Carry Ore or Bulk Cargoes (Under 150 m (492 ft) in Length)
Section 1 Introduction 5C-4-1

1.11 Protection of Structure

For the protection of structure, see 3-2-18/5.

1.13 Selection of Material Grade (1 July 2009)

Steel materials for particular locations are not to be of lower grades than those required by 3-1-2/Table 1
for the material class given in 3-1-2/Table 2, except the special application for single-side skin bulk
carriers subject to SOLAS regulation XII/6.5.3 as indicated in 5C-4-1/Table 1.

TABLE 1
Minimum Material Grades for Single-side Skin Bulk Carriers
Subject to SOLAS Regulation XII/6.5.3 (1 July 2009)
Line No. Structural Members Material Grade
(1, 2)
BC1 Lower bracket of ordinary side frame
Side shell strakes included totally or partially between the two D/DH
BC2 points located to 0.125l above and below the intersection of side
shell and bilge hopper sloping plate or inner bottom plate (2)
Notes:
1 “Lower bracket” means webs of lower brackets and webs of the lower part of side
frames up to the point of 0.125l above the intersection of side shell and bilge hopper
sloping plate or inner bottom plate.
2 The span of the side frame, l, is defined as the distance between the supporting structures.

3 Carriage of Oil Cargoes

3.1 General
Ore carriers and bulk carriers intended also for the carriage of oil cargoes, as defined in 5C-2-1/1, are to
comply with the applicable parts of Section 5C-2-1 as well as this section.

3.3 Gas Freeing

Prior to and during the handling of bulk or ore cargoes, all spaces except slop tanks are to be free of cargo
oil vapors.

3.5 Slop Tanks

Slop tanks are to be separated from spaces that may contain sources of vapor ignition by oiltight and adequately
vented cofferdams, as defined in 5C-2-1/5.3, or by cargo oil tanks which are maintained gas free.

5 Special Requirements for Deep Loading

Bulk carriers or ore carriers to which freeboards are assigned based on the subdivision requirements of the
International Convention on Load Lines, 1966, are to comply with those regulations.

7 Forecastle (2004)

7.1 General
These requirements apply to all bulk carriers, ore carriers and combination carriers. These vessels are to be
fitted with an enclosed forecastle on the freeboard deck in accordance with the requirements in this section.

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Chapter 4 Vessels Intended to Carry Ore or Bulk Cargoes (Under 150 m (492 ft) in Length)
Section 1 Introduction 5C-4-1

7.3 Arrangements (2007)

The forecastle is to be located on the freeboard deck with its aft bulkhead fitted in way or aft of the
forward bulkhead of the foremost hold, as shown in 5C-4-1/Figure 1. However, if this requirement hinders
hatch cover operation, the aft bulkhead of the forecastle may be fitted forward of the forward bulkhead of
the foremost cargo hold provided the forecastle length is not less than 0.07Lf (Lf: see 3-1-1/3.3) abaft the
forward perpendicular.
A breakwater is not to be fitted on the forecastle deck with the purpose of protecting the hatch coaming or
hatch covers. If fitted for other purposes, it is to be located such that its upper edge at center line is not less
than HB /tan 20° forward of the aft edge of the forecastle deck, where HB is the height of the breakwater
above the forecastle (see 5C-4-1/Figure 1).

7.5 Dimensions
7.5.1 Heights
The forecastle height, HF, above the main deck at side is to be not less than:

• The standard height of a superstructure as specified in the International Convention on Load

Line 1966 and its Protocol of 1988, or
• HC + 0.5 m, where HC is the height of the forward transverse hatch coaming of cargo hold No. 1,
whichever is the greater.
7.5.2 Location of Aft Edge of Forecastle Deck
All points of the aft edge of the forecastle deck are to be located at a distance lF:

l F ≤ 5 H F − HC

from the No.1 hatch forward coaming plate in order to apply the reduced loading to the No. 1
forward transverse hatch coaming and No. 1 hatch cover in applying 5C-4-2/13.

7.7 Structural Arrangements and Scantlings

The structural arrangements and scantlings of the forecastle are to comply with the applicable requirements
of 3-2-2/5.7, 3-2-5/5, 3-2-7/3, 3-2-11/1.3 and 3-2-11/9.

FIGURE 1
HB
Top of the hatch coaming

HF
HC

lF

Forward
bulkhead

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 573
PART Section 2: Hull Structure

5C
CHAPTER 4 Vessels Intended to Carry Ore or Bulk Cargoes
(Under 150 meters (492 feet) in Length)

SECTION 2 Hull Structure

1 Hull Girder Strength

1.1 Normal-strength Standard

The longitudinal hull girder strength is to be as required by the equations given in Section 3-2-1.

1.3 Hull Girder Shear and Bending Moments

For shear and bending moment calculation requirements, see Section 3-2-1.

1.5 Loading Guidance

Loading Guidance is to be as required by 3-2-1/7.

3 Transverse Bulkheads in Hold (1995)

Transverse bulkheads in holds are to be in accordance with 5C-4-1/1.5. For corrugated bulkheads, the
distance, l, between supporting members, may be measured between the upper and lower stools, except
that the credit for upper stools of rectangular cross section is not to exceed twice the width of the cross
section.

5 Shell Plating (1 July 1998)

Shell plating is to be not less in thickness than required by Section 3-2-1 and Section 3-2-2. In addition, the
thickness of the side shell plating in way of cargo holds of single side skin bulk carriers is not to be less
than given by:
tmin = (L)1/2 mm tmin = 0.02175(L)1/2 in.
where L is the length of the vessel, as defined in 3-1-1/3.1, in m (ft).

7 Deck Plating
Deck plating is to be not less in thickness than required by Section 3-2-1 and Section 3-2-3.

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Chapter 4 Vessels Intended to Carry Ore or Bulk Cargoes (Under 150 m (492 ft) in Length)
Section 2 Hull Structure 5C-4-2

9 Double-bottom and Tank Structure

9.1 General
The double bottom is generally to be arranged with a centerline girder, or equivalent, and full-depth side
girders, in accordance with Section 3-2-4, except that the side girders are to be spaced approximately 3 m
(10 ft). The scantlings of the double-bottom structure are to be in accordance with Section 3-2-4, except as
modified in this section. Increases may be required when cargo is to be carried in alternate holds. It is
recommended that the depth of double bottom forward be increased where subject to slamming forces and
that unnecessary openings in the floors and girders be avoided. See also 5C-4-1/1.5. Where ducts forming
a part of the double bottom structure are used as a part of the piping system for transferring cargo oil or
ballast, the structural integrity of the duct is to be safeguarded by suitable relief valves or other
arrangement to limit the pressure in the system to the value for which it is designed. See also 5C-4-1/1.5.

9.3 Floors and Transverses

In general, transverse floors under the cargo holds are to be spaced not more than 3 m (10 ft) and their
thickness is to be as required by Section 3-2-4. Closely spaced transverses or floors fitted in the lower wing
tanks are to have thickness as required by 3-2-4/5 for floors, intercostals and brackets elsewhere.

9.5 Bottom Longitudinals and Side Tank Framing

Bottom longitudinals are to be in accordance with 3-2-4/11.3. Side members in lower wing tanks or side
tanks in bulk carriers, as well as shell frames and longitudinal bulkhead-stiffeners in ore carriers, are to
have a section modulus SM not less than that obtained from the following equation:
SM = 7.8chsl2 cm3 SM = 0.0041chsl2 in3
where
c = 1.00 for vertical side shell frames and vertical stiffeners on bulkheads
= 0.95 for side shell longitudinals
= 0.90 for horizontal stiffeners on bulkheads
h = for frames, the distance, in m (ft), from the longitudinal or from the middle of l for
vertical members, to the load line, or to a point located two-thirds of the distance
from the keel to the bulkhead or freeboard deck, whichever is greater.
= for bulkhead stiffeners, the distance measured to a point located two-thirds of the
distance from the top of the tank to the top of the overflow, and in no case is h to be
less than the distance measured to a point located above the top of the tank as given
in column (e) of 3-2-7/Table 1, appropriate to the vessel’s length
s = spacing of the members, in m (ft)
l = length of unsupported span, in m (ft)
Longitudinals around the bilge are to be graded in size from that required for the lowest side longitudinal
to that required for bottom longitudinals. Shell longitudinals are to be at least as required by Section 3-2-9
or Section 3-2-10 for bulkhead stiffeners and by 3-2-5/3.17 for side longitudinals.

9.7 Inner-bottom Longitudinals

The section modulus SM of each inner-bottom longitudinal is not to be less than 85% of that required for
bottom longitudinals, nor is to be less than that obtained from the following equation:
SM = kcnhsl2 cm3 (in3)

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Chapter 4 Vessels Intended to Carry Ore or Bulk Cargoes (Under 150 m (492 ft) in Length)
Section 2 Hull Structure 5C-4-2

where
k = 7.8 (0.0041)
c = 1.12 for vessels intended for bulk cargo
= 1.75 for vessels specially reinforced for ore cargo or for loading in alternate holds
n = 0.40 (1 + V/1041) for vessels intended for bulk cargo SI and
= V/2403 for vessels specially reinforced for ore cargo or MKS
for loading in alternate holds Units

= 0.40 (1 + V/65) for vessels intended for bulk cargo US

= V/150 for vessels specially reinforced for ore cargo or Units
for loading in alternate holds
In no case is n to be less than 0.80.
V = cargo deadweight, in kg (lb), divided by the total volume of the holds, in m3 (ft3).
Where the cargo is not uniformly distributed in all holds, the value of V is to be
checked for each hold [cargo deadweight of each hold, in kg (lb), divided by the
volume of the hold, in m3 (ft3)], and where in any one hold it exceeds the mean value
calculated as directed above, the longitudinals of that hold are to be increased
accordingly.
h = distance, in m (ft), from the inner bottom to the deck at centerline, or for inner bottom
longitudinals located directly under upper wing tanks to the underside of the upper
wing tank.
s = spacing of longitudinals, in m (ft)
l = spacing of the floors, in m (ft)

9.9 Inner-bottom Plating

The inner-bottom plating is to be not less than required by 3-2-4/9.1 and 3-2-4/9.3 and is to be flush
throughout the cargo space.
Where ore or heavy bulk cargoes are carried or where cargo is handled by grabs, the requirements of
3-2-4/9.1 are to be suitably increased, but the increase need not exceed 5 mm (0.20 in.).
For vessels specially designed as ore carriers, it is recommended that the minimum thickness of inner
bottom be 19 mm (0.75 in.) at 510 mm (20 in.) spacing of longitudinals.

9.11 Tank Bulkhead Plating

The thickness of the transverse and longitudinal bulkheads of side or wing tanks is not to be less than that
required by 3-2-10/3.1 for the spacing of stiffeners and the distance h, in m (ft), measured from the lower
edge of the plating to a point located at two-thirds of the distance from the top of the tank to the top of the
overflow. In no case is h to be less than the distance measured to a point located above the top of the tank
as given in column (e) of 3-2-7/Table 1, appropriate to the vessel’s length.
For vessels intended to carry cargo oil, the thickness of the transverse or longitudinal bulkheads of side or
wing tanks is to be not less than required by 5C-2-2/7.1.
Where a sloped part of the tank bulkhead plating is within or near the line of the cargo hatch, it is
recommended that the part of the sloping bulkhead within or near the line of the cargo hatch be suitably
reinforced.

9.13 Lower Wing Tank Stiffeners

The section modulus for each stiffener on the lower wing tank bulkheads is to be in accordance with
5C-4-2/9.5, or as determined by the equation in 5C-4-2/9.7, except that for the latter, h is to be measured
from the longitudinal or, in the case of vertical stiffeners, from the middle of l.

576 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 4 Vessels Intended to Carry Ore or Bulk Cargoes (Under 150 m (492 ft) in Length)
Section 2 Hull Structure 5C-4-2

9.15 Transverse Webs

Each transverse web in the lower wing tanks, where fitted in bulk carriers, is to have a section modulus SM
not less than that obtained from the following equation:
SM = 4.74chsl2 cm3 SM = 0.0025chsl2 in3
where
c = 1.5 for side-shell, bottom-shell and wing-tank bulkheads.
s, h, l are as defined under 5C-4-2/9.5
Transverse webs are to be in line with the solid floors and are to have depths of not less than 0.145l (1.75 in/ft
of span l). In general, the depth is to be not less than two times the depth of the slots. See also 5C-4-2/9.3.

9.17 Carriage of Water Ballast or Liquid Cargoes in Cargo Holds

Where a cargo hold is intended to be used for the carriage of water ballast or liquid cargoes, the hold is in
general to be assumed completely filled and the scantlings of the inner bottom, side structure, transverse
bulkheads, deck and hatch covers are also to be in accordance with Section 3-2-10. The hatch cover and
securing devices are to be suitable for the internal loading. See 3-2-15/9.
Special consideration may be given to the scantlings of cargo holds partially filled with water ballast or
liquid cargoes, and full particulars are to be submitted.

11 Framing

11.1 Transverse Hold Framing (1 July 1998)

11.1.1 Frames
Transverse hold frames are to meet the requirements in Section 3-2-5, as modified below.
For a bulk carrier having upper and lower wing tanks with adequately spaced transverse strength
bulkheads, the section modulus SM is not to be less than that obtained from the following equation.
SM = 3.5sh1l2 cm3 SM = 0.00185sh1l2 in3
where
h1 = h+P
s = frame spacing, in m (ft)
l = unsupported span of frames, in m (ft), as indicated in 5C-4-2/Figure 1
h = vertical distance, in m (ft), from the middle of l to the load line

P = C1(1.09 _ 0.65h/d) m

= 3.28C1(1.09 _ 0.65h/d) ft
C1 = as defined in 3-2-1/3.5.1
d = molded draft, as defined in 3-1-1/9
The web depth to thickness ratio is to comply with the requirements of 5C-1-A2/11.9.
The ratio of outstanding flange breadth to thickness is not to exceed 10 Q where Q is as defined
in 3-2-1/5.5.
11.1.2 Frame Brackets (1998)
11.1.2(a) The section modulus SME of the frame and bracket measured at the heels of the frame
attachment is to be at least 2.0 times the SM required by 5C-4-2/11.1.1 above. See 5C-4-2/Figure 1.

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Part 5C Specific Vessel Types
Chapter 4 Vessels Intended to Carry Ore or Bulk Cargoes (Under 150 m (492 ft) in Length)
Section 2 Hull Structure 5C-4-2

11.1.2(b) Side frames of higher tensile steels are to be symmetrical sections with integral upper
and lower brackets. The brackets are to be soft toed.
The flange of the frame is to be curved (not knuckled) at the transition to the integral brackets and
the radius of curvature is not to be less than r, in mm (in.), given by:
r = 0.4 bf2/tf
where
tf = flange thickness of the bracket, in mm (in.)
bf = flange width, in mm (in.)
11.1.2(c) Where frames and brackets are of ordinary strength steel, the frames may be asymmetric
or rolled sections and fitted with separate brackets. The brackets are to be soft toed at their heels
and the face plate or flange sniped at both ends.
11.1.2(d) Integral or separate frame brackets are to extend at least for a length of 0.125h3 onto the
frame, and the depth of the bracket plus frame measured at the heel of the frame is generally to be
at least 1.5 times that of the frame. Where the hull form renders this impracticable, equivalent
strength in shear and bending is to be provided. The brackets are to be arranged with “soft” toes.
See 5C-4-2/Figure 2 and 5C-4-2/Figure 3.
11.1.3 Minimum Thickness
11.1.3(a) Frames and Upper Brackets. The thickness of upper brackets and the web portions of
the frames are not to be less than that obtained from the following equations:
t = 0.03L1 + 7 mm
t = 0.00036L1 + 0.28 in.
L1 = scantling length of the vessel, in m (ft), as defined in 3-1-1/3.1
In the foremost cargo hold, the thickness given in 5C-4-2/11.1.3(a) above is to be increased by a
factor of 1.15.
11.1.3(b) Lower Brackets. The thickness of the brackets at the lower end of frames is to be at
least 2 mm (0.08 in.) greater than the minimum thickness of web portions of frames required by
5C-4-2/11.1.3(a) above or the actual thickness of the web of the frame being supported, whichever
is greater.
11.1.4 Supporting Brackets
Brackets are to be fitted in the lower and upper wing tanks in line with every side frame. These
brackets are to be stiffened against buckling.
11.1.5 Longitudinals at the Toe of Brackets
The section moduli of side longitudinals and sloping bulkhead longitudinals at the toe of brackets
are to be determined as per 5C-4-2/9.5, 5C-4-2/9.13 and 5C-4-2/11.3, with length l equal to the
unsupported span between transverses and spacing s equal to “b”, as indicated in 5C-4-2/Figure 3.
11.1.6 Tripping Brackets
When the frames in the foremost hold are asymmetric sections, tripping brackets are to be fitted at
every two frames at approximately mid-span, as shown in 5C-4-2/Figure 4.
11.1.7 Side Frame Aft of Collision Bulkhead
In order to prevent large relative deflection of the side shell plating, e.g., panels just aft of the
collision bulkhead, the section modulus of the first two frames aft of this bulkhead is to be at least
2.5 times the requirement in 5C-4-2/11.1.1 above. Other means of achieving this, such as brackets
in line with forepeak structures, will be considered.

578 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 4 Vessels Intended to Carry Ore or Bulk Cargoes (Under 150 m (492 ft) in Length)
Section 2 Hull Structure 5C-4-2

11.3 Upper Wing Tank Framing

Each structural section for the side shell and wing tank stiffener and deck longitudinal in way of upper
wing tanks is to have a section modulus SM not less than that obtained from the following equation:
SM = 7.8chsl2 cm3 SM = 0.0041chsl2 in3
where
c = 0.95 for side-shell longitudinals
= 0.90 for bulkhead longitudinals
= 1.00 for vertical side frames and bulkhead stiffeners
= 1.05 for deck longitudinals
h = distance, in m (ft), from the center of the area supported to a point located two-thirds
of the distance from the top of the tank to the top of the overflow, and in no case is h
to be less than the distance measured to a point located above the top of the tank, as
given in column (e) of 3-2-7/Table 1, appropriate to the vessel’s length, except for
deck members where column (a) of 3-2-7/Table 1 applies
s = spacing of member, in m (ft)
l = unsupported span, in m (ft)

11.5 Transverse Webs

Each transverse web in the upper wing tanks, where fitted, is to have a section modulus SM not less than
that obtained from the following equation:
SM = 4.74chsl2 cm3 SM = 0.0025chsl2 in3
where
c = 1.50 for shell and sloping-bulkhead webs and deck transverses
s, h, l are as defined under 5C-4-2/11.3.
The webs in the upper wing tanks are to have depths of not less than 0.0832l (1 in. per ft of span).
Thickness is to be not less than 1 mm per 100 mm (0.01 in. per in.) of depth plus 4 mm (0.16 in.), but is to
be not less than 8 mm (0.31 in.) and need not exceed 11 mm (0.44 in.). In general, the depth is to be not
less than twice the depth of the slots.

13 Cargo Hold Hatch Covers, Coamings and Closing Arrangements (2004)

13.1 General
On all bulk carriers, ore carriers and combination carriers, all cargo hold hatch covers, hatch coamings and
closing arrangements for cargo hold hatches in position 1, as defined in 3-2-15/3.1, are to meet the
requirements in 5C-3-4/19 using the design pressures as indicated in 5C-4-2/13.3.

13.3 Hatch Cover Design Pressures

The following hatch cover design pressure, p, is to be used in conjunction with 5C-3-4/19:
For ships of 100 m (328 ft) in length and above:
p = p0 + (pFP – p0)(0.25 – x/Lf)/0.25 kN/m2 (tf/m2, Ltf/ft2)
For ships less than 100 m (328 ft) in length:
p = R{15.8 + (Lf/N)[1 – (5/3)(x/Lf)] – 3.6x/Lf } kN/m2 (tf/m2, Ltf/ft2)

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 579
Part 5C Specific Vessel Types
Chapter 4 Vessels Intended to Carry Ore or Bulk Cargoes (Under 150 m (492 ft) in Length)
Section 2 Hull Structure 5C-4-2

where
p0 = 34.3 (3.5, 0.32) kN/m2 (tf/m2, Ltf/ft2)
pFP = pressure at the forward perpendicular

= 49.0 + a(Lf – 100) kN/m2 for Lf in meters

= 5 + a(Lf – 100) tf/m2 for Lf in meters

= 0.457 + a(Lf – 328) Ltf/ft2 for Lf in feet

a = 0.0726 (0.0074, 0.000206) kN/m2 (tf/m2, Ltf/ft2), for type B freeboard ships
= 0.356 (0.0363, 0.00101) kN/m2 (tf/m2, Ltf/ft2), for ships with reduced freeboard
Lf = freeboard length, in m (ft), as defined in 3-1-1/3.3
x = distance, in m (ft), from the mid length of the hatch cover under examination to the
forward end of Lf, or 0.25Lf, whichever is less.
R = 1.0 (0.102, 0.00932)
N = 3 (3, 9.84)
For ships of 100 m (328 ft) in length and above, where a position 1 hatchway is located at least one
superstructure standard height higher than the freeboard deck, the pressure p may be 34.3 kN/m2 (3.5 tf/m2,
0.32 Ltf/ft2).
Special consideration is to be given for design pressures of ships less than 24 m (79 ft).

15 Testing
Requirements for testing are contained in Section 3-7-1.

17 Self-unloading Gear
Requirements for self-unloading gear are contained in 5C-3-7/7.

580 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 4 Vessels Intended to Carry Ore or Bulk Cargoes (Under 150 m (492 ft) in Length)
Section 2 Hull Structure 5C-4-2

FIGURE 1
Length of Hold Frame (1 July 1998)

Upper
Wing Tank

b
SME 1.5b

l Unsupported
Span

SM E
1.5b1
b1

Lower
Wing Tank

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 581
Part 5C Specific Vessel Types
Chapter 4 Vessels Intended to Carry Ore or Bulk Cargoes (Under 150 m (492 ft) in Length)
Section 2 Hull Structure 5C-4-2

FIGURE 2 (1 July 1998)

0.5d
(in general)

0.125h3

d
WEB HEIGHT

FIGURE 3 (1 July 1998)

SOFT TOE

582 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 4 Vessels Intended to Carry Ore or Bulk Cargoes (Under 150 m (492 ft) in Length)
Section 2 Hull Structure 5C-4-2

FIGURE 4 (1 July 1998)

HOLD NO. 1

ASYMMETRIC

BHD
SIDE FRAME

FP

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 583
PART Section 3: Cargo Safety and Vessel Systems

5C
CHAPTER 4 Vessels Intended to Carry Ore or Bulk Cargoes
(Under 150 meters (492 feet) in Length)

SECTION 3 Cargo Safety and Vessel Systems

See Section 5C-3-7.

584 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
PART Chapter 5: Vessels Intended to Carry Containers (130 meters (427 feet) to 350 meters (1476 feet) in Length)

5C
CHAPTER 5 Vessels Intended to Carry Containers (130 meters
(427 feet) to 450 meters (1476 feet) in Length)

CONTENTS
SECTION 1 Introduction ........................................................................................ 594
1 General ...........................................................................................594
1.1 Classification ............................................................................... 594
1.2 Optional Class Notation for Design Fatigue Life.......................... 594
1.3 Application................................................................................... 594
1.5 Arrangement................................................................................ 595
1.7 Submission of Plans .................................................................... 595
3 Section Properties of Structural Members ......................................595

FIGURE 1.....................................................................................................596

SECTION 2 Design Considerations and General Requirements........................ 597

1 General Requirements....................................................................597
1.1 General........................................................................................ 597
1.3 Initial Scantling Requirements ..................................................... 597
1.5 Strength Assessment-Failure Modes .......................................... 597
1.7 Structural Redundancy and Residual Strength............................ 597
3 Nominal Design Corrosion Values (NDCV) ....................................598

TABLE 1 Nominal Design Corrosion Values (NDCV) for Container

Carriers .................................................................................600

FIGURE 1 Nominal Design Corrosion Values (NDCV) ..........................599

SECTION 3 Load Criteria ....................................................................................... 601

1 General ...........................................................................................601
1.1 Load Components ....................................................................... 601
3 Static Loads ....................................................................................601
3.1 Still-water Bending Moments, Shear Forces and Torsional
Moment ....................................................................................... 601
3.3 Cargo Container Loads ............................................................... 604
5 Wave-induced Loads ......................................................................604
5.1 Wave-induced Longitudinal Bending and Torsional Moments
and Shear Forces........................................................................ 604
5.3 External Pressures and Impact Loads......................................... 607
5.5 Cargo Loads and Liquid Pressure ............................................... 610

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 585
 7 Nominal Design Loads....................................................................634
7.1 Hull Girder Loads – Longitudinal Bending Moments, Shear
Forces and Torsional Moment .....................................................634
7.3 Local Loads for Design of Supporting Structures ........................634
7.5 Local Pressures for Design of Plating and Longitudinals.............635
9 Combined Load Cases ...................................................................635
9.1 Combined Load Cases for Structural Analysis ............................635
9.3 Combined Load Cases for Strength Assessment ........................635
11 Impact Loads ..................................................................................636
11.1 Bottom Slamming Pressure .........................................................636
11.3 Bowflare Slamming......................................................................637
13 Other Loads ....................................................................................643
13.1 Vibrations.....................................................................................643
13.3 Ice Loads .....................................................................................643
13.5 Accidental Loads .........................................................................643

TABLE 1A Combined Load Cases for Yielding and Buckling Strength

Formulation ...........................................................................623
TABLE 1B Combined Load Cases for Fatigue Strength Formulation ....627
TABLE 2 Design Pressure for Local and Supporting Members ...........630
TABLE 3 Values of α ............................................................................640
TABLE 4 Values of Ai and Bi ................................................................640

FIGURE 1 Sign Conventions ..................................................................602

FIGURE 2 Distribution Factor fMV............................................................602
FIGURE 3 Loading Pattern of Container Carrier ....................................603
FIGURE 4 Distribution Factor mh ............................................................617
FIGURE 5 Distribution Factor fh ..............................................................617
FIGURE 6 Distribution Factor mT ............................................................618
FIGURE 7 Torsional Moment Distribution Curves..................................618
FIGURE 8 Distribution of Hydrodynamic Pressure.................................619
FIGURE 9 Hydrodynamic Pressure Distribution Factor klo.....................619
FIGURE 10 Illustration of Determining Total External Pressure ..............620
FIGURE 11 Definition of Bow Geometry ..................................................620
FIGURE 12 Distribution of Container Loads to Corners in Hold ..............621
FIGURE 13 Transfer of Container Corner Loads on the Cell Guide to
Support Points.......................................................................621
FIGURE 14 Definition of Tank Geometry .................................................622
FIGURE 15 Location of Hold for Nominal Pressure Calculation ..............632
FIGURE 16 Nominal Pressure Calculation Procedure for
Non-Prismatic Tank...............................................................632
FIGURE 17 Applicable Areas of Design Pressures..................................633
FIGURE 18 Distribution of Bottom Slamming Pressure Along the
Section Girth .........................................................................641
FIGURE 19 Ship Stem Angle, γ................................................................641
FIGURE 20 Definition of Bow Flare Geometry for Bow Flare Shape
Parameter .............................................................................642
FIGURE 21 Definition of Half Deck Width ................................................642

586 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
 SECTION 4 Initial Scantling Criteria ..................................................................... 644
1 General ...........................................................................................644
1.1 Strength Requirements ............................................................... 644
1.3 Calculation of Load Effects.......................................................... 644
1.5 Structural Details ......................................................................... 644
1.7 Evaluation of Grouped Stiffeners................................................. 644
3 Hull Girder Strength ........................................................................646
3.1 Hull Girder Section Modulus........................................................ 646
3.3 Hull Girder Moment of Inertia ...................................................... 646
3.5 Transverse Strength .................................................................... 646
5 Hull Girder Shearing Strength.........................................................646
5.1 General........................................................................................ 646
5.3 Net Thickness of Side Shell Plating............................................. 647
5.5 Net Thickness of the Longitudinal Bulkhead Plating.................... 647
7 Hull Girder Torsional Stiffness ........................................................648
9 Torsion-induced Longitudinal Stress ..............................................649
9.1 Total Torsion-induced Longitudinal Stress, (Warping Stress)...... 649
9.3 Wave-induced Warping Stress .................................................... 649
9.5 Still-water Warping Stress ........................................................... 651
9.7 Permissible Warping Stress ........................................................ 652
11 Double Bottom Structures...............................................................657
11.1 General........................................................................................ 657
11.3 Bottom Shell and Inner Bottom Plating........................................ 657
11.5 Bottom and Inner Bottom Longitudinals ...................................... 660
11.7 Bilge Plate and Longitudinals/Frames ......................................... 661
11.9 Bottom Struts............................................................................... 662
11.11 Centerline Girder in way of Cargo Holds ..................................... 662
11.13 Bottom Side Girders .................................................................... 663
11.15 Longitudinally Stiffened Bottom Girders ...................................... 664
11.17 Bottom Tank Boundary Girders ................................................... 664
11.19 Vertical Web on Bottom Tank Boundary Girder........................... 665
11.21 Bottom Floors .............................................................................. 666
11.23 Tank End Floors .......................................................................... 666
11.25 Transverses in Pipe Tunnel......................................................... 666
11.27 Container Supporting Structures ................................................. 667
13 Side Shell Plating and Longitudinals ..............................................671
13.1 Side Shell Plating ........................................................................ 671
13.3 Side Longitudinals and Side Frames........................................... 674
13.5 Side Struts................................................................................... 676
15 Side Transverses and Side Stringers .............................................676
15.1 Side Transverse in Double Side Structures................................. 677
15.3 Side Transverse in Single Side Shell .......................................... 678
15.5 Side Transverse in Underdeck Passageway ............................... 679
15.7 Side Stringers in Double Side Structures .................................... 680
15.9 Transverses Forming Tank Boundaries....................................... 681
15.11 Side Stringers Forming Tank Boundaries.................................... 681
15.13 Container Supporting Structures ................................................. 683

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 587
 17 Deck Structures ..............................................................................684
17.1 Strength Deck Plating ..................................................................684
17.3 Strength Deck Longitudinals........................................................685
17.5 Upper Wing Torsional Box...........................................................685
17.7 Cross Deck Structure...................................................................687
17.9 Longitudinal Deck Girders Inboard of Lines of Openings.............689
17.11 Deck Transverse in Underdeck Passageway ..............................691
17.13 Underdeck Passageway (Second Deck) .....................................691
19 Hatch Coamings and Hatch Covers ...............................................694
19.1 Hatch Coamings ..........................................................................694
19.3 Hatch Covers ...............................................................................694
21 Longitudinal Bulkheads...................................................................694
21.1 Tank Bulkhead Plating.................................................................694
21.3 Tank Bulkhead Longitudinals/Stiffeners.......................................697
21.5 Watertight Bulkhead Plating ........................................................698
21.7 Watertight Bulkhead Longitudinals/Stiffeners ..............................699
21.9 Longitudinals in Upper Wing Torsional Box .................................699
21.11 Transverse Web on Longitudinal Bulkhead in Underdeck
Passageway ................................................................................699
23 Transverse Bulkheads – Plating and Stiffeners..............................701
23.1 Tank Bulkhead Plating.................................................................701
23.3 Tank Bulkhead Stiffeners.............................................................701
23.5 Watertight Bulkhead Plating ........................................................702
23.7 Watertight Bulkhead Stiffeners ....................................................702
23.9 Underdeck Passageway ..............................................................702
25 Watertight Bulkhead Main Supporting Members ............................702
25.1 Transverse Watertight Bulkhead .................................................702
25.3 Mid-hold Strength Bulkhead ........................................................706
25.5 Minimum Thickness and Stiffening Arrangement of Webs ..........709

FIGURE 1 Scantling Requirement Reference by Subsection ................645

FIGURE 2 Improvement of Hatch Corners and Heavy Insert Deck
Plate ......................................................................................645
FIGURE 3 Strength Deck Definition of l1, l2, b0, b0′, B and B′ ................653
FIGURE 4 Deck Structure ......................................................................654
FIGURE 5 Specified Stations and Coefficients for Warping Stress
Calculation ............................................................................655
FIGURE 6 Unsupported Span of Longitudinals......................................668
FIGURE 7 Effective Breadth of Plating be ...............................................669
FIGURE 8 Definitions of ls, bs, h, db, dw, ds and y.....................................670
FIGURE 9 Effectiveness of Brackets for Main Supporting Members .....671
FIGURE 10 Definitions of h1 and h2 ..........................................................692
FIGURE 11 Sizes of Insert Plates ............................................................693
FIGURE 12 Transverse Watertight and Mid-hold Strength Bulkhead
Definition of Spans for Bulkhead without Bottom Stool ........710
FIGURE 13 Transverse Watertight and Mid-hold Strength Bulkhead
Definitions of Spans for Bulkhead with Bottom Stool............710

588 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
 SECTION 5 Total Strength Assessment............................................................... 711
1 General Requirements....................................................................711
1.1 General........................................................................................ 711
1.3 Loads and Load Cases ............................................................... 711
1.5 Stress Components ..................................................................... 711
1.7 Structural Details ......................................................................... 712
3 Yielding Criteria...............................................................................712
3.1 General........................................................................................ 712
3.3 Structural Members and Elements .............................................. 712
3.5 Plating ......................................................................................... 713
5 Buckling and Ultimate Strength Criteria..........................................714
5.1 General........................................................................................ 714
5.3 Plate Panels ................................................................................ 714
5.5 Longitudinals and Stiffeners ........................................................ 716
5.7 Stiffened Panels .......................................................................... 717
5.9 Deep Girders and Webs .............................................................. 717
5.11 Longitudinal Deck Girders, Cross Deck Box Beams and
Vertical Webs .............................................................................. 718
5.13 Hull Girder Ultimate Strength....................................................... 719
7 Fatigue Life .....................................................................................720
7.1 General........................................................................................ 720
7.3 Procedures .................................................................................. 721
7.5 Spectral Analysis......................................................................... 721
9 Calculation of Structural Responses...............................................722
9.1 Methods of Approach and Analysis Procedures.......................... 722
9.3 3D Finite Element Models ........................................................... 722
9.5 2D Finite Element Models ........................................................... 722
9.7 Refined 3D Local Structural Models ............................................ 722
9.9 Load Cases ................................................................................. 722
11 Critical Areas...................................................................................722

FIGURE 1 Critical Areas.........................................................................723

SECTION 6 Hull Structure Beyond 0.4L Amidships ............................................ 724

1 General Requirements....................................................................724
1.1 General........................................................................................ 724
1.3 Structure within Cargo Spaces .................................................... 724
3 Bottom Shell Plating and Stiffeners in Forebody ............................724
3.1 Bottom Shell Plating .................................................................... 724
3.3 Bottom Longitudinals and Transverse Frames ............................ 725
5 Side Shell Plating and Stiffeners in Forebody ................................726
5.1 Side Shell Plating ........................................................................ 726
5.3 Forecastle Side Shell Plating....................................................... 726
5.5 Stem Plating ................................................................................ 727
5.7 Bow Thruster Tunnel ................................................................... 727
5.9 Immersed Bow Plating................................................................. 727
5.11 Side Longitudinals and Transverse Frames ................................ 728

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 589
 7 Side Transverses and Stringers in Forebody .................................731
7.1 Transverse Web Frames .............................................................731
7.3 Stringers ......................................................................................732
7.5 Fore Peak-stringer .......................................................................732
9 Deck Structures ..............................................................................733
9.1 Strength Deck Plating Outside Line of Openings.........................733
9.3 Strength Deck Plating Within Line of Openings ...........................734
9.5 Forecastle Decks .........................................................................734
9.7 Platform Decks in Enclosed Spaces ............................................734
9.9 Watertight Flats............................................................................735
9.11 Deck Longitudinals and Beams ...................................................735
9.13 Deck Girders and Transverses Clear of Tanks............................736
9.15 Deck Girders and Transverses in Tanks......................................737
11 Pillars or Struts................................................................................737
11.1 Permissible Load .........................................................................737
11.3 Calculated Load...........................................................................738
11.5 Pillars under the Tops of Deep Tanks..........................................738
13 Transition Zone ...............................................................................738
13.1 General........................................................................................738
15 Fore-peak Structure ........................................................................739
15.1 General........................................................................................739
15.3 Center Girder and Floor Plating ...................................................739
15.5 Peak Frames ...............................................................................739
17 Watertight Bulkheads......................................................................739
17.1 Plating..........................................................................................739
17.3 Stiffeners .....................................................................................740
17.5 Girders and Webs........................................................................741
19 Deep Tank Bulkheads.....................................................................741
19.1 Plating..........................................................................................741
19.3 Stiffeners .....................................................................................742
19.5 Girders and Webs........................................................................743
21 Collision Bulkheads.........................................................................743
21.1 Plating..........................................................................................743
21.3 Stiffeners .....................................................................................744
21.5 Girders and Webs........................................................................745
23 Structure Strengthening for Impact Loads ......................................746
23.1 Bottom Slamming ........................................................................746
23.3 Bowflare Slamming......................................................................747
23.5 Bow Strengthening ......................................................................754
25 Aftbody and Machinery Space Structure ........................................755
25.1 Bottom Structure..........................................................................755
25.3 Double Bottom in Engine Space ..................................................756
25.5 Side Shell Structures ...................................................................758
25.7 Side Transverse Web Frames and Stringers...............................761
25.9 Decks...........................................................................................763
25.11 Pillars...........................................................................................767
25.13 After-peak ....................................................................................768
25.15 Watertight Bulkheads...................................................................769

590 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
 25.17 Deep Tank Bulkheads ................................................................. 771
25.19 Machinery Space......................................................................... 773

TABLE 1 Coefficient c2 .........................................................................749

TABLE 2 Coefficient c3 .........................................................................749
TABLE 3 Coefficient c4 .........................................................................749
TABLE 4 Coefficient c1 .........................................................................752
TABLE 5 Coefficient c3 .........................................................................752

FIGURE 1 Transverse Frames...............................................................730

FIGURE 2 Web Frames..........................................................................733
FIGURE 3 Definition of Spans................................................................750

SECTION 7 Cargo Safety ....................................................................................... 774

1 Application ......................................................................................774
3 Container Cargo Spaces.................................................................774
3.1 General Fire Protection ............................................................... 774
3.3 Vessels Intended to Carry Dangerous Goods ............................. 774
5 Refrigerated Containers..................................................................774

TABLE 1 Dangerous Goods Classes ...................................................775

TABLE 2 Application of Requirements to Container Cargo Spaces ....775
TABLE 3 Application of the Requirements in 4-7-2/7.3 to Different
Classes of Dangerous Goods, Except Solid Dangerous
Goods in Bulk........................................................................776

APPENDIX 1 Guide for Fatigue Strength Assessment of Container Carriers ..... 777
1 General ...........................................................................................777
1.1 Note............................................................................................. 777
1.3 Applicability ................................................................................. 777
1.5 Loadings...................................................................................... 777
1.7 Effects of Corrosion..................................................................... 777
1.9 Format of the Criteria .................................................................. 778
3 Connections to be Considered for the Fatigue Strength
Assessment ....................................................................................778
3.1 General........................................................................................ 778
3.3 Guidance on Locations................................................................ 778
3.5 Fatigue Classification .................................................................. 779
5 Permissible Stress Range...............................................................789
5.1 Assumption.................................................................................. 789
5.3 Criteria......................................................................................... 790
5.5 Long Term Stress Distribution Parameter, γ ................................ 790
5.7 Permissible Stress Range ........................................................... 791
7 Calculation of Fluctuating Loads and Determination of Total
Stress Ranges ................................................................................794
7.1 General........................................................................................ 794
7.3 Wave-induced Loads................................................................... 794

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 591
 7.5 Resulting Stress Ranges .............................................................794
7.7 Primary Stress fd1 .........................................................................797
7.9 Secondary Stress fd2i ...................................................................797
7.11 Additional Secondary Stresses f*d2 and Tertiary Stresses fd3i .....799
7.13 Calculation of Stress Range for Side Frame and Vertical
Stiffener on Longitudinal Bulkhead ..............................................801
9 Determination of Stress Concentration Factors (SCFs) .................805
9.1 General........................................................................................805
9.3 Sample Stress Concentration Factors (SCFs).............................805
9.5 Hatch Corner ...............................................................................809
11 Stress Concentration Factors Determined from Finite Element
Analysis...........................................................................................821
11.1 General........................................................................................821
11.3 S-N Data......................................................................................821
11.5 S-N Data and SCFs .....................................................................822
11.7 Calculation of Hot Spot Stress for Fatigue Analysis of Ship
Structures ....................................................................................824

TABLE 1 Fatigue Classification for Structural Details ..........................780

TABLE 2 Welded Joint with Two or More Load Carrying Members.....783
TABLE 2A Coefficient, C.........................................................................791
TABLE 3 Combined Load Cases for Container Carriers......................804
TABLE 4 Coefficient k3b for Double Bottom Panels ..............................805
TABLE 5 Coefficient ai and bi for Double Bottom Panels .....................805
TABLE 6 Ks (SCF) Values ....................................................................805

FIGURE 1 Basic Design S-N Curves .....................................................792

FIGURE 2 Dimensions of Double Bottom and Double Side...................802
FIGURE 3 Cn = Cn (ψ) .............................................................................803
FIGURE 4 Cut-outs (Slots) For Longitudinal ..........................................807
FIGURE 5 Fatigue Classification for Longitudinals in way of Flat Bar
Stiffener.................................................................................809
FIGURE 6 Side Hatch Corners...............................................................819
FIGURE 7 Circular Shape ......................................................................820
FIGURE 8 Double Curvature Shape ......................................................820
FIGURE 9 Elliptical Shape......................................................................820
FIGURE 10 Hatch Corner for Longitudinal Deck Girder...........................821
FIGURE 11...................................................................................................823
FIGURE 12...................................................................................................823
FIGURE 13...................................................................................................824
FIGURE 14...................................................................................................825

APPENDIX 2 Calculation of Critical Buckling Stresses......................................... 826

1 General ...........................................................................................826
3 Rectangular Plates..........................................................................826

592 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
 5 Longitudinal Deck Girders, Cross Deck Box Beams, Vertical
Webs, Longitudinals and Stiffeners ................................................829
5.1 Axial Compression ...................................................................... 829
5.3 Bending ....................................................................................... 829
5.5 Torsional/Flexural Buckling ......................................................... 831
7 Stiffened Panels..............................................................................835
9 Deep Girders, Webs and Stiffened Brackets ..................................836
9.1 Critical Buckling Stresses of Web Plates and Large
Brackets ...................................................................................... 836
9.3 Effects of Cut-outs ....................................................................... 836
9.5 Tripping ....................................................................................... 837
11 Stiffness and Proportions................................................................837
11.1 Stiffness of Longitudinals............................................................. 838
11.3 Stiffness of Web Stiffeners .......................................................... 838
11.5 Stiffness of Supporting Members ................................................ 838
11.7 Proportions of Flanges and Face Plates...................................... 839
11.9 Proportions of Webs of Longitudinals and Stiffeners................... 839

TABLE 1 Buckling Coefficient, Ki .........................................................827

FIGURE 1 Net Dimensions and Properties of Stiffeners........................833

FIGURE 2 Torsional Properties..............................................................834
FIGURE 3.....................................................................................................836

APPENDIX 3 Definition of Hull Girder Torsional Properties ................................. 840

1 General ...........................................................................................840
3 Warping Function, ω .......................................................................840
5 Location of Shear Center, e ............................................................841
7 Warping Constant, Γ .......................................................................841
9 St. Venant Torsional Constant, J ....................................................841

APPENDIX 4 Guide for Hull Girder Ultimate Strength Assessment of

Container Carriers.............................................................................. 842
1 General ...........................................................................................842
3 Vertical Hull Girder Ultimate Limit State .........................................842
5 Hull Girder Ultimate Bending Moment Capacity .............................843
5.1 General........................................................................................ 843
5.3 Physical Parameters ................................................................... 844
5.5 Calculation Procedure ................................................................. 845
5.7 Assumptions and Modeling of the Hull Girder Cross-section....... 846
5.9 Stress-strain Curves σ-ε (or Load-end Shortening Curves)......... 848

FIGURE 1 Bending Moment – Curvature Curve M-κ .............................843

FIGURE 2 Dimensions and Properties of Stiffeners ..............................845
FIGURE 3 Example of Defining Structural Elements .............................847
FIGURE 4 Example of Stress Strain Curves σ-ε ....................................848

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 593
PART Section 1: Introduction

5C
CHAPTER 5 Vessels Intended to Carry Containers (130 meters
(427 feet) to 450 meters (1476 feet) in Length)

SECTION 1 Introduction

1 General

1.1 Classification (1 July 2001)

In accordance with 1-1-3/3 and 1-1-3/25, the classification notation À A1 Container Carrier, SH, SHCM
is to be assigned to vessels designed primarily for the carriage of containers in holds or on deck or both,
with structures for that purpose, such as cell guides, pedestals, etc., and built to the requirements of this
Chapter and other relevant Sections of the Rules.

1.2 Optional Class Notation for Design Fatigue Life (2003)

Vessels designed and built to the requirements in this Chapter are intended to have a structural fatigue life
of not less than 20 years. Where a vessel’s design calls for a fatigue life in excess of the minimum design
fatigue life of 20 years, the optional class notation FL (year) will be assigned at the request of the
applicant. This optional notation is eligible, provided the excess design fatigue life is verified to be in
compliance with the criteria in Appendix 1 of this Chapter, “Guide for Fatigue Strength Assessment of
Container Carriers.” Only one design fatigue life value is published for the entire structural system. Where
differing design fatigue life values are intended for different structural elements within the vessel, the
(year) refers to the least of the varying target lives. The ‘design fatigue life’ refers to the target value set
by the applicant, not the value calculated in the analysis.
The notation FL (year) denotes that the design fatigue life assessed according to Appendix 1 of this
Chapter is greater than the minimum design fatigue life of 20 years. The (year) refers to the fatigue life
equal to 25 years or more (in 5-year increments), as specified by the applicant. The fatigue life will be
identified in the Record by the notation FL (year); e.g., FL(30) if the minimum design fatigue life
assessed is 30 years.

1.3 Application (1998)

1.3.1 Size and Proportions (1 July 2005)
The requirements contained in this Chapter are applicable to container carriers in the range of 130
to 450 meters (427 to 1476 feet) in length, having proportions within the range as specified in 3-2-1/1
and are intended for unrestricted service.
1.3.2 Vessel Types
The equations and formulae for determining design load and strength requirements as specified in
Section 5C-5-3 and Section 5C-5-4 are applicable to container carriers with either double-sided or
single-sided construction. In general, the strength assessment procedure and failure criteria as
specified in Section 5C-5-5 are applicable to all types of container carriers.

594 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 1 Introduction 5C-5-1

1.3.3 Direct Calculations (1 July 2005)

For a vessel with length greater than 250 meters (820 feet), the torsional response and critical
structural details beyond 0.4L amidships are to be evaluated using a full ship finite element model
unless a proven design or an equivalent analysis result is available.
For a vessel with length in excess of 350 meters (1148 feet), the hull structure and critical structural
details are to comply with the requirements of the Dynamic Loading Approach and Spectral Fatigue
Analysis. For analysis using the Dynamic Loading Approach, acceptance of an equivalent method
can be considered by ABS. The vessel will be identified in the Record by the notations SH-DLA
and SFA.
Direct calculations with respect to the determination of design loads and the establishment of
alternative strength criteria based on first principles will be accepted for consideration, provided
all the supporting data, analysis procedures and calculated results are fully documented and
submitted for review. In this regard, due consideration is to be given to the environmental conditions,
probability of occurrence, uncertainties in load and response predictions, and reliability of the
structure in service. For long term prediction of wave loads, realistic wave spectra covering the
North Atlantic Ocean and a probability level of 10-8 are to be employed.
1.3.4 SafeHull Construction Monitoring Program (1 July 2001)
For the class notation SH, SHCM, a Construction Monitoring Plan for critical areas, prepared in
accordance with the requirements of Part 5C, Appendix 1, is to be submitted for approval prior to
comencement of fabrication. See Part 5C, Appendix 1 “Guide for SafeHull Construction Monitoring
Program.”

1.5 Arrangement
Strength bulkheads or combined deep webs and substantial partial bulkheads are to be provided in accordance
with 3-2-9/1.7. Upper wing torsional boxes or double hull side construction are to be provided in way of
container holds having wide deck openings.

1.7 Submission of Plans

In addition to the plans listed elsewhere in the Rules (see Section 1-1-7), the following plans are to be submitted.
Stowage arrangement of containers including stacking loads and height. Location of container supports and
their connection to hull.

3 Section Properties of Structural Members (1 July 2008)

The geometric properties of structural members may be calculated directly from the dimensions of the
section and the associated effective plating (see 3-1-2/13.3 or 5C-5-4/Figure 6, as applicable). For structural
members with angle θ between web and associated plating not less than 75 degrees, the section modulus,
web sectional area and moment of inertia of the “standard” (θ = 90 degrees) section may be used without
modification. Where the angle θ is less than 75 degrees, the sectional properties are to be directly
calculated about an axis parallel to the associated plating. (See 5C-5-1/Figure 1)
For longitudinals, frames and stiffeners, the section modulus may be obtained by the following equation:
SM = αθSM90
where
αθ = 1.45 – 40.5/θ
SM90 = the section modulus at θ = 90 degrees
The effective section area may be obtained from the following equation:
A = A90 sin θ
where
A90 = effective shear area at θ = 90 degrees

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 595
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 1 Introduction 5C-5-1

FIGURE 1 (1998)

dw

θ = 90°

Standard

dw

596 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
PART Section 2: Design Considerations and General Requirements

5C
CHAPTER 5 Vessels Intended to Carry Containers (130 meters
(427 feet) to 450 meters (1476 feet) in Length)

SECTION 2 Design Considerations and General Requirements

1 General Requirements (1998)

1.1 General (1998)

The strength requirements specified in this Chapter are based on a “net” ship approach. In determining
compliance with the required scantlings, and performing structural analyses and strength assessments, the
nominal design corrosion values given in 5C-5-2/Table 1 are to be deducted from the offered scantlings.

1.3 Initial Scantling Requirements (1998)

The initial plating thicknesses, section moduli of longitudinals/stiffeners and the scantlings of the main
supporting structures are to be determined in accordance with Section 5C-5-4 for the “net” ship for further
assessment, as required in the following paragraph. The relevant nominal design corrosion values are then
added to obtain the full scantling requirements.

1.5 Strength Assessment-Failure Modes (1998)

A total assessment of the structures determined on the basis of the initial strength criteria in Section 5C-5-4
is to be carried out against the following three failure modes.
1.5.1 Material Yielding
The calculated stress intensities are not to be greater than the yielding state limit given in 5C-5-5/3
for all load cases specified in 5C-5-3/9.
1.5.2 Buckling and Ultimate Strength
For each individual member, plate or stiffened panel, the buckling and ultimate strength are to be
in compliance with the requirements specified in 5C-5-5/5. In addition, the hull girder ultimate
strength is to be in accordance with 5C-5-5/5.13.
1.5.3 Fatigue
The fatigue strength of structural details and welded joints in highly stressed regions is to be in
accordance with 5C-5-5/7.

1.7 Structural Redundancy and Residual Strength (1998)

Consideration is to be given to structural redundancy and hull girder residual strength in the early design
stages.
Vessels which have been built in accordance with the procedures and criteria for calculating and evaluating
the residual strength of hull structures in the ABS Guide for Assessing Hull-Girder Residual Strength, in
addition to other requirements of these Rules, will be classed and distinguished in the Record by the
symbol RES placed after the appropriate hull classification notation.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 597
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 2 Design Considerations and General Requirements 5C-5-2

3 Nominal Design Corrosion Values (NDCV) (1998)

As indicated in 5C-5-2/1.1, the strength criteria specified in this Chapter are based on a “net” ship approach,
wherein the nominal design corrosion values are deducted.
The “net” thickness or scantlings correspond to the minimum strength requirements acceptable for
classification, regardless of the design service life of the vessel. In addition to the coating protection specified
in the Rules, minimum corrosion values for plating and structural members, as given in 5C-5-2/Table 1 and
5C-5-2/Figure 1, are to be applied. These minimum corrosion values are being introduced solely for the
above purpose, and are not to be construed as renewal standards.
In view of the anticipated higher corrosion rates for structural members in some regions, such as highly
stressed areas, it is advisable to consider additional design margins for the primary and critical structural
members to minimize repairs and maintenance costs. The beneficial effects of these design margins on
reduction of stresses and increase of the effective hull girder section modulus can be appropriately
accounted for in the design evaluation.

598 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 2 Design Considerations and General Requirements 5C-5-2

FIGURE 1
Nominal Design Corrosion Values (NDCV) (2007)
NOTES
1) In splash zone (1.5 meters down from 2nd deck), use uniform
corrosion value of 2.0 mm (0.08 in.) for all internal members
within this zone. Boundary plating of tank is considered according
to 5C-5-2/Table 1.
2) It is recognized that corrosion depends on many factors
including coating properties, cargo and temperature of carriage
and that actual wastage rates observed may be appreciably
different from those given here.
3) Pitting and grooving are regarded as localized phenomena
LONGITUDINAL BULKHEAD
and are not covered in 5C-5-2/Table 1.
HATCH COAMINGS INCLUDING STAYS
1.0 mm - PLATE IN TANK SPACE
1.0 mm - STIFFENER WEB 1.5 mm - PLATE***
1.0 mm - STIFFENER FLANGE 1.0 mm - STIFFENER WEB*
1.0 mm - STIFFENER FLANGE*
IN DRY SPACE LONGITUDINAL DECK GIRDER
STRENGTH DECK 1.0 mm - PLATE AND CROSS DECK BOX BEAM
OUTBOARD OF LINES OF HATCH OPENINGS 1.0 mm - STIFFENER WEB 0.5 mm - PLATE
1.5 mm - PLATE 1.0 mm - STIFFENER FLANGE 0.5 mm - STIFFENER WEB
1.0 mm - STIFFENER WEB 0.5 mm - STIFFENER FLANGE
1.0 mm - STIFFENER FLANGE
INBOARD OF LINES OF HATCH OPENINGS
1.0 mm - PLATE
1.0 mm - STIFFENER WEB
1.0 mm - STIFFENER FLANGE

SIDE SHELL
IN TANK SPACE
1.5 mm - PLATE
1.0 mm - STIFFENER WEB*
1.0 mm - STIFFENER FLANGE*
IN DRY SPACE
1.0 mm - PLATE
1.0 mm - STIFFENER WEB
1.0 mm - STIFFENER FLANGE

SIDE STRINGER
TIGHT**
2.0 mm - PLATE
2.0 mm - STIFFENER WEB
2.0 mm - STIFFENER FLANGE
NON-TIGHT
1.5 mm - PLATE TRANSVERSE BULKHEAD
1.0 mm - STIFFENER WEB IN TANK SPACE
2.0 mm - STIFFENER FLANGE** 1.5 mm - PLATE***
IN VOID SPACE 1.0 mm - STIFFENER WEB*
1.0 mm - PLATE 1.0 mm - STIFFENER FLANGE*
1.0 mm - STIFFENER WEB IN DRY SPACE
1.0 mm - STIFFENER FLANGE 0.5 mm - PLATE
TRANSVERSE WEB 0.5 mm - STIFFENER WEB
IN TANK SPACE 0.5 mm - STIFFENER FLANGE
1.5 mm - PLATE
1.0 mm - STIFFENER WEB*
1.0 mm - STIFFENER FLANGE*
IN DRY SPACE
1.0 mm - PLATE
1.0 mm - STIFFENER WEB
1.0 mm - STIFFENER FLANGE

TRANSVERSE IN PIPE DUCT SPACE

1.0 mm - PLATE
1.0 mm - WEB
1.0 mm - FLANGE

TIGHT FLAT FORMING RECESSES OR STEPS

BOTTOM AND BILGE 1.5 mm - PLATE
IN TANK SPACE 2.0 mm - STIFFENER WEB**
1.0 mm - PLATE 2.0 mm - STIFFENER FLANGE**
2.0 mm - STIFFENER WEB**
2.0 mm - STIFFENER FLANGE** INNER BOTTOM
IN PIPE DUCT SPACE
1.0 mm - PLATE 1.5 mm - PLATE
2.0 mm - STIFFENER WEB**
1.0 mm - STIFFENER WEB
C.L.
1.0 mm - STIFFENER FLANGE 2.0 mm - STIFFENER FLANGE**
DOUBLE BOTTOM FLOOR IN PIPE DUCT SPACE
IN TANK SPACE** 1.0 mm - PLATE
DOUBLE BOTTOM GIRDER 2.0 mm - PLATE 1.0 mm - STIFFENER WEB
IN TANK SPACE** 2.0 mm - STIFFENER WEB 1.0 mm - STIFFENER FLANGE
2.0 mm - PLATE 2.0 mm - STIFFENER FLANGE
2.0 mm - STIFFENER WEB
2.0 mm - STIFFENER FLANGE IN PIPE DUCT SPACE
IN PIPE DUCT SPACE 1.5 mm - PLATE
1.0 mm - PLATE 1.0 mm - STIFFENER WEB * 2.0 mm For Non-Vertical Web or Flange (also see **)
1.0 mm - STIFFENER WEB 1.0 mm - STIFFENER FLANGE ** May be reduced to 1.5 mm if located inside Fuel Oil Tank
1.0 mm - STIFFENER FLANGE
STRUT *** May be reduced to 1.0 mm (0.04 in.) if located between dry
IN DOUBLE BOTTOM TANK
2.0 mm - PLATE** and tank spaces
IN SIDE TANK
1.0 mm - PLATE*

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 599
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 2 Design Considerations and General Requirements 5C-5-2

TABLE 1
Nominal Design Corrosion Values (NDCV)
for Container Carriers (2007)
Nominal Design Corrosion Values in mm (in.)
Attached Stiffeners
Structural Element/Location Plate Web Flange
Strength Deck Outboard of Lines of Hatch Openings 1.5 (0.06) 1.0 (0.04) 1.0 (0.04)
Inboard of Lines of Hatch Openings 1.0 (0.04) 1.0 (0.04) 1.0 (0.04)
Side Shell In Tank Space 1.5 (0.06) 1.0 (0.04) * 1.0 (0.04) *
In Dry Space 1.0 (0.04) 1.0 (0.04) 1.0 (0.04)
Bottom and Bilge In Tank Space 1.0 (0.04) 2.0 (0.08) ** 2.0 (0.08) **
In Pipe Duct Space 1.0 (0.04) 1.0 (0.04) 1.0 (0.04)
Inner Bottom In Tank Space 1.5 (0.06) 2.0 (0.08) ** 2.0 (0.08) **
In Pipe Duct Space 1.0 (0.04) 1.0 (0.04) 1.0 (0.04)
Longitudinal Bulkhead In Tank Space 1.5 (0.06) *** 1.0 (0.04) * 1.0 (0.04) *
In Dry Space 1.0 (0.04) 1.0 (0.04) 1.0 (0.04)
Transverse Bulkhead In Tank Space 1.5 (0.06) *** 1.0 (0.04) * 1.0 (0.04) *
(except for Cross Deck Box Beam) In Dry Space 0.5 (0.02) 0.5 (0.02) 0.5 (0.02)
Transverse Web In Tank Space 1.5 (0.06) 1.0 (0.04) * 1.0 (0.04) *
In Dry Space 1.0 (0.04) 1.0 (0.04) 1.0 (0.04)
Tight Flat forming Recesses or Steps (except 2nd deck) 1.5 (0.06) 2.0 (0.08) ** 2.0 (0.08) **
Side Stringer Tight ** 2.0 (0.08) 2.0 (0.08) 2.0 (0.08)
Non-Tight 1.5 (0.06) 1.0 (0.04) 2.0 (0.08) **
In Void Space 1.0 (0.04) 1.0 (0.04) 1.0 (0.04)
Double Bottom Girder In Tank ** 2.0 (0.08) 2.0 (0.08) 2.0 (0.08)
In Pipe Duct Space 1.0 (0.04) 1.0 (0.04) 1.0 (0.04)
Double Bottom Floor In Tank ** 2.0 (0.08) 2.0 (0.08) 2.0 (0.08)
In Pipe Duct Space 1.0 (0.04) 1.0 (0.04) 1.0 (0.04)
Transverse in Pipe Duct Space 1.5 (0.06) 1.0 (0.04) 1.0 (0.04)
Longitudinal Deck Girder and Box Beam 0.5 (0.02) 0.5 (0.02) 0.5 (0.02)
Hatch Coamings including Stays 1.0 (0.04) 1.0 (0.04) 1.0 (0.04)
Hatch Cover 1.0 (0.04) 1.0 (0.04) 1.0 (0.04)
Strut In Double Bottom Tank -- 2.0 (0.08) **
In Side Tank -- 1.0 (0.04) *

* 2.0 mm (0.08 in.) for non vertical members (also see ***)
** May be reduced to 1.5 mm (0.06 in.) if located inside fuel oil tank
*** May be reduced to 1.0 mm (0.04 in.) if located between dry and tank spaces
Notes: 1 In splash zone (1.5 meters down from 2nd deck), use uniform corrosion value of 2.0 mm (0.08 in.) for all internal
members within this zone. Boundary plating of tank is considered according to the above table.
2 It is recognized that corrosion depends on many factors including coating properties, cargo and temperature of
carriage and that actual wastage rates observed may be appreciably different from those given here.
3 Pitting and grooving are regarded as localized phenomena and are not covered in this table.

600 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
PART Section 3: Load Criteria

5C
CHAPTER 5 Vessels Intended to Carry Containers (130 meters
(427 feet) to 450 meters (1476 feet) in Length)

SECTION 3 Load Criteria

1 General

1.1 Load Components (1998)

In the design of the hull structure of container carriers, all load components with respect to the hull girder
and local structure as specified in this Chapter and Section 3-2-1 are to be taken into account. These
include static loads in still water, wave-induced hull girder loads, wave-induced internal and external
loads, slamming, impact loads and other loads, where applicable.

3 Static Loads (1998)

The sign convention for bending, MH, and torsional moments, TS, and shear forces, FH, is as follows in
5C-5-3/Figure 1.

3.1 Still-water Bending Moments, Shear Forces and Torsional Moment (1 July 2005)
For still-water bending moment and shear force calculations, see 3-2-1/3.3.
Envelope curves are also to be provided for the still-water bending moments (hogging and sagging) and
shear forces (positive and negative).
Except for special loading cases, the loading patterns shown in 5C-5-3/Figure 3 are to be considered in
determining local static loads.
Still-water torsional moment due to uneven distribution of cargo and other weights is to be considered.
Unless the maximum still-water torsional moment is specified in the loading manual, the following equation
may be used to calculate still-water torsional moment amidships:
TS = ± k B WT kN-m (tf-m, Ltf-ft)
where
k = 0.004
B = breadth of vessel, as defined in 3-1-1/5, in m (ft)
WT = maximum total container weight of vessel, kN (tf, Ltf)
The sign convention for bending, MH, and torsional moments, TS, and shear forces, FH, is shown in
5C-5-3/Figure 1.
The still-water torsional moment along the length of the vessel L may be obtained by multiplying the
midship value by the distribution factor mT as given in 5C-5-3/Figure 6.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 601
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 3 Load Criteria 5C-5-3

FIGURE 1
Sign Conventions

(+)
FH

(+)
MH

TS, TM
(+)
(+)

FIGURE 2
Distribution Factor fMV

1.0

fMV

0.0
0.0 0.4 0.65 1.0
Aft Forward
end of L end of L
Distance from the aft end of L in terms of L

602 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
 Part

Section
Chapter
3 Load Criteria

LOAD CASE 1 LOAD CASE 2 LOAD CASE 3 LOAD CASE 4 LOAD CASE 5
Heading 0 Deg. Heading 0 Deg. Heading 0 Deg. Heading 0 Deg. Heading 90 Deg.
Heave Down Heave Up Heave Down Heave Up Heave Down
5C Specific Vessel Types

Pitch Bow Down Pitch Bow Up Pitch Bow Down Pitch Bow Up Pitch -
Roll - Roll - Roll - Roll - Roll STBD Down
Draft 2/3 Draft Full Draft 2/3 Draft Full Draft 2/3
Wave VBM Sag Wave VBM Hog Wave VBM Sag Wave VBM Hog Wave VBM Sag

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

FIGURE 3

LOAD CASE 6 LOAD CASE 7 LOAD CASE 8 LOAD CASE 9 LOAD CASE 10
Heading 90 Deg. Heading 60 Deg. Heading 60 Deg. Heading 60 Deg. Heading 60 Deg.
Heave Up Heave Down Heave Up Heave Up Heave Down
Pitch - Pitch Bow Down Pitch Bow Up Pitch Bow Up Pitch Bow Down
Roll STBD Up Roll STBD Down Roll STBD Up Roll STBD Up Roll STBD Down
Draft 2/3 Draft 2/3 Draft Full Draft 2/3 Draft Full
Wave VBM Hog Wave VBM Sag Wave VBM Hog Wave VBM Sag Wave VBM Hog
Loading Pattern of Container Carrier (1 July 2005)

Light Cargo Heavy Cargo

Ballast, S.G. = 1.025
5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)

7 mt per TEU as a maximum 14 mt per TEU as a minimum

Heavy cargo 14 mt per TEU as a minimum, but

need not be more than the maximum weight per
TEU calculated rom the approved stack weight
in hold and on deck.

603
5C-5-3
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 3 Load Criteria 5C-5-3

3.3 Cargo Container Loads (1998)

The cargo container loads acting on the supporting structure in still water may be determined based on the
weight of containers and may be distributed as given in 5C-5-3/5.5.2. The stowage arrangement of containers
including stacking loads and heights is to be submitted for review.

5 Wave-induced Loads (1998)

Where a direct calculation of the wave-induced loads [i.e., longitudinal bending moments and shear forces,
hydrodynamic pressures (external) and inertial forces and added pressure heads (internal)] is not available,
the approximation equations given below and specified in 3-2-1/3.5 may be used to calculate the design
loads.
When a direct calculation is performed, envelope curves for the combined wave and still-water bending
moments and shear forces, covering all the anticipated loading conditions, are to be submitted for review.

5.1 Wave-induced Longitudinal Bending and Torsional Moments and Shear Forces
5.1.1 Vertical Wave Bending Moment (1 July 2005)
The vertical wave bending moment amidships, expressed in kN-m (tf-m, Ltf-ft), may be obtained
from the following equations:
Mw = kw Mws Wave Sagging Moment
Mw = kw Mwh Wave Hogging Moment
where
kw = 1.0 for the nominal wave bending moment in the determination of the hull
girder section modulus in 5C-5-4/3.1.1 and the bowflare slamming effects on
hull girder sagging bending moment in 5C-5-3/11.3.3
= (1.84 – 0.56Cb) for wave sagging bending moment used in strength
formulation and assessment of local structural elements and members in
Section 5C-5-4, 5C-5-5/1, 5C-5-5/3 and 5C-5-5/5
= 1.0 for wave hogging bending moment used in strength formulation and
assessment of local structural elements and members in Section 5C-5-4,
5C-5-5/1, 5C-5-5/3 and 5C-5-5/5
= (1.09 + 0.029V − 0.47Cb)1/2 for wave hogging and sagging bending moments
used in fatigue strength formulation in 5C-5-5/7 and Appendix 5C-5-A1
V = 75% of the design speed, Vd, in knots.
V need not to be taken greater than 24 knots.
Vd = the design speed, as defined in 3-2-14/3
Mws, Mwh and Cb are as defined in 3-2-1/3.5.1.

5.1.2 Vertical Wave Shear Force (1 July 2005)

The envelopes of the maximum wave-induced shearing forces, Fw, expressed in kN (tf, Ltf), may
be obtained from the following equations:
Fw = kw Fwp for positive shear force (upward front section)
Fw = kw Fwn for negative shear force (downward front section)
where
kw = 1.0 for the nominal wave-induced positive and negative shear forces in
determination of shearing strength in 5C-5-4/5 and bowflare slamming
effects on hull girder positive shear force in 5C-5-3/11.3.3

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Section 3 Load Criteria 5C-5-3

kw = kwp for positive shear force (upward front section)

kw = kwn for negative shear force (downward front section)
kwp and kwn are for wave-induced shear forces used in strength formulation and assessment of local
structural elements and members in Section 5C-5-5, Linear interpolation may be used for intermediate
values.
kwp = 1.0 at AP

= (1.61 – 0.47 Cb)1/2 from 0.2L to 0.3L from AP

= 1.0 from 0.4L to 0.6 L from AP
= 1.5 from 0.7L to 0.85L from AP
= 1.0 at FP
kwn = 1.0 at AP
= 1.5 from 0.2L to 0.3L from AP
= 1.0 from 0.4L to 0.6L from AP
= 1.1(1.61 – 0.47 Cb)1/2 from 0.7L to 0.85L from AP
= 1.0 at FP
kw = (1.09 + 0.029V − 0.47Cb)1/2 for positive and negative wave-induced shear
forces used in fatigue strength formulation in 5C-5-5/7 and Appendix
5C-5-A1
Fwp, Fwn are the envelopes of maximum wave-induced vertical shearing forces, as defined in
3-2-1/3.5.3, wherein Cb is not to be taken less than 0.6. V is as defined in 5C-5-3/5.1.1.
5.1.3 Horizontal Wave Bending Moment (1 July 2005)
The horizontal wave bending moment amidships, expressed in kN-m (tf-m, Ltf-ft), positive
(tension port) or negative (tension starboard), may be obtained from the following equation:
MH = ± ks K3 C1 L2 D (Cb + 0.7) × 10-3
where
ks = (1.61 – 0.47 Cb)1/2 for strength formulation and assessment of local structural
elements and members in Sections 5C-5-4 and 5C-5-5
= (1.09 + 0.029V − 0.47Cb)1/2 for fatigue strength formulation in 5C-5-5/7 and
Appendix 5C-5-A1
K3 = 104.2 (10.62, 0.973)
L = length of vessel, as defined in 3-1-1/3.1, in m (ft)
D = depth of vessel, as defined in 3-1-1/7, in m (ft)
C1 is as given in 3-2-1/3.5.1.
Cb is as defined in 3-2-1/3.5.1 and is not to be taken less than 0.6.
V is as defined in 5C-5-3/5.1.1.
The horizontal wave bending moment along the length of the vessel L may be obtained by
multiplying the midship value by the distribution factor mh, as given in 5C-5-3/Figure 4.

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 3 Load Criteria 5C-5-3

5.1.4 Horizontal Wave Shear Force (1 July 2005)

The envelope of the horizontal wave shear force, FH, expressed in kN (tf, Ltf), positive (toward
port front section) or negative (toward starboard front section), may be obtained from the following
equation:
FH = fh ks k C1 L D (Cb + 0.7) × 10-2 kN (tf, Ltf)
where
ks = (1.61 – 0.47 Cb)1/2 for strength formulation and assessment of local structural
elements and members in Sections 5C-5-4 and 5C-5-5
= (1.09 + 0.029V − 0.47Cb)1/2 for fatigue strength formulation in 5C-5-5/7 and
Appendix 5C-5-A1.
fh = distribution factor, as given in 5C-5-3/Figure 5
k = 36 (3.67, 0.34)
C1, L, D and Cb are as defined in 5C-5-3/5.1.3 above. V is as defined in 5C-5-3/5.1.1.

5.1.5 Wave-induced Torsional Moment

5.1.5(a) Nominal Wave-induced Torsional Moment (1 July 2005). The nominal wave-induced
torsional moment amidships, in kN-m (tf-m, Ltf-ft), positive clockwise looking forward, may be
determined as follows:
TM = ks k L B2d [(Cw − 0.5)2 + 0.1] [0.13 − (e/D)(co/d)1/2]
where
ks = (1.61 – 0.47Cb)1/2 for strength formulation and assessment of local structural
elements and members in Sections 5C-5-4 and 5C-5-5
= (1.09 + 0.029V − 0.47Cb)1/2 for fatigue strength formulation in 5C-5-5/7 and
Appendix 5C-5-A1.
k = 2.7 (0.276, 0.077)
co = 0.14 (0.14, 0.459)
d = draft, as defined in 3-1-1/9, in m (ft); its value is not to be taken less than
12.5 m (41 ft)
e = the vertical distance, in m (ft), of the effective shear center of the hull girder
within cargo space, measured from the baseline of the vessel, positive upward.
The effective shear center may be calculated by considering an open section of the cargo hold
nearest to midship.
Cw = waterplane coefficient for the draft d. If not available, it may be approximated
by Cw = Cb + 0.2, but need not to be taken greater than 0.9 for typical
container carriers
L, B and D are as defined in 3-1-1/3.1, 3-1-1/5, and 3-1-1/7, respectively.
Cb is as defined in 3-2-1/3.5.1 and is not to be taken less than 0.6.
V is as defined in 5C-5-3/5.1.1.
5.1.5(b) Distribution of Wave-induced Torsional Moment. The nominal wave induced torsional
moment along the length of the vessel L may be obtained by multiplying the midship value by the
distribution factor mT, as given in 5C-5-3/Figure 6.

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 3 Load Criteria 5C-5-3

5.1.5(c) Simultaneous Distribution of Wave-induced Torsional Moment. When a direct calculation

is not available, the wave-induced torsional moment, T(x), along the length of vessel at an
instantaneous time may be approximated by the following equations. For assessing the structural
response to torsion, i.e., distortions and warping stresses, at least two different torsional moment
distribution curves in a critical region, such as in front of the engine room, are to be considered.
One curve gives approximately a peak value of the torsional moment, one shows a maximum
slope of the moment curve. Three sample torsional moment distribution curves are shown in
5C-5-3/Figure 7. These three curves should be considered as the least set to assess torsional
responses for the engine room region, amidships, and the forward quarter length region, respectively.
A: T(x) = TM [0.8 sin [2π (x/L − 0.025)] + 0.2], for 0.05L ≤ x ≤ 0.95L

B: T(x) = TM [0.7 cos [2.72π (x/L − 0.5)] + 0.3], for 0.05L ≤ x ≤ 0.95L

C: T(x) = -TM [0.75 sin (2π x/L) + 0.05], for 0.05L ≤ x ≤ 0.95L
T(x) = 0, at x = 0 and x = 1.0L
where
TM is as defined in 5C-5-3/5.1.5(a) above.
x is the distance from the aft end of L to station considered, in m (ft).
L is as defined in 3-1-1/3.1.

5.3 External Pressures and Impact Loads (1998)

5.3.1 Pressure Distribution (1 July 2005)
The external pressures, pe, positive toward inboard, imposed on the hull in a seaway can be expressed
by the following equation at a given location:
pe = ρ g(hs + kuhde) ≥ 0 N/cm2 (kgf/cm2, lbf/in2)
where
ρg = specific weight of sea water
= 1.005 N/cm2-m (0.1025 kgf/cm2-m, 0.4444 lbf/in2-ft)
hs = hydrostatic pressure head in still water, in m (ft)
ku = load factor, and may be taken as unity unless otherwise specified
hde = hydrodynamic pressure head induced by the wave, in m (ft), may be
calculated as follows
hde = kchdi
where
kc = correlation factor for a specific combined load, as given in 5C-5-3/Table 1
and 5C-5-3/Table 2
hdi = hydrodynamic pressure head, in m (ft), at location i, (i = 1, 2, 3, 4 or 5; see
5C-5-3/Figure 8)
= klαi hdo, in m (ft)
kl = distribution factor along the length of the vessel
= 1 + (klo − 1) cos μ, klo is as given in 5C-5-3/Figure 9
= 1.0 amidships
hdo = 1.36 ks C1

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 3 Load Criteria 5C-5-3

ks = 1.0 for strength formulation and assessment of local structural elements and
members in Sections 5C-5-4 and 5C-5-5
= (1.09 + 0.029V − 0.47Cb)1/2 for fatigue strength formulation in 5C-5-5/7 and
Appendix 5C-5-A1
C1 = as defined in 3-2-1/3.5.1
αi = distribution factor around the girth of vessel at location “i”, linearly
interpolated at other locations
= 1.00 − 0.25 cos μ, for i = 1, at WL, starboard
= 0.40 − 0.10 cos μ, for i = 2, at bilge, starboard
= 0.30 − 0.20 sin μ, for i = 3, at bottom centerline
= 2 α3 − α2, for i = 4, at bilge, port
= 0.75 − 1.25 sin μ, for i = 5, at WL, port
μ = wave heading angle in degrees, to be taken from 0° to 90° (0° for head sea,
90° for beam sea for wave coming from starboard)
The distribution of the total external pressure including static and hydrodynamic pressures is
illustrated in 5C-5-3/Figure 10.
Cb is as defined in 3-2-1/3.5.1 and is not to be taken less than 0.6. V is as defined in 5C-5-3/5.1.1.

5.3.2 Extreme Pressures

In determining the required scantlings of local structural members, the extreme external pressure,
pe, as defined in 5C-5-3/5.3.1 with ku and kc given in 5C-5-3/7 and 5C-5-3/9, is to be used.

5.3.3 Simultaneous Pressures

For performing 3D structural analysis, the simultaneous pressure along any portion of the hull
girder may be obtained from:
pes = ρ g(hs + kf ku hde) ≥ 0 N/cm2 (kgf/cm2, lbf/in2)
where
kf is the distribution function of hde corresponding to a designated wave profile along the vessel’s
length, and may be determined as follows:
5.3.3(a) For the combined load cases, L.C.1 through L.C.6 specified in 5C-5-3/Table 1
kf = kfo {1− [1 − cos 2π (x/L − xo/L) ] cos μ}
5.3.3(b) For the combined load cases, L.C.7 and L.C.8 specified in 5C-5-3/Table 1
kf = kfo cos {4π (x/L − xo/L − 0.25) cos μ}
5.3.3(c) For the combined load cases, L.C.9 and L.C.10 specified in 5C-5-3/Table 1
kf = kfo cos {4π (x/L − xo/L + 0.25) cos μ}
5.3.3(d) For the combined load cases, L.C. F1 and L.C. F2 specified in 5C-5-A1/Table 3
kf = kfo cos {4π (x/L − xo/L) cos μ}
where
x = distance from AP to the station considered, in m (ft)
xo = distance from AP to the reference station, in m (ft).
The reference station is the point along the vessel length where the wave
trough or crest is located in head seas, and may be taken as the mid-point of
the middle hold of tbe three hold model.

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 3 Load Criteria 5C-5-3

L is the vessel length, as defined in 3-1-1/3.1, in m (ft).

μ is the wave heading angle, in degrees, as defined in 5C-5-3/5.3.1.
kfo = ± 1.0, as specified in 5C-5-3/Table 1 and 5C-5-A1/Table 3
The simultaneous pressure distribution around the girth of the vessel is to be determined based on
the wave heading angles specified in 5C-5-3/Table 1 and 5C-5-A1/Table 3.
5.3.4 Impact Loads on Bow and Deck
5.3.4(a) Bow Pressures. When experimental data or direct calculation is not available, nominal
wave-induced bow pressures above the load waterline (LWL) in the region from the forward end
to the collision bulkhead may be obtained from the following equations:
pbij = k Ck Cij Vij2 sin γij kN/m2 (tf/m2, Ltf/ft2)
where
k = 1.025 (0.1045, 0.00888)
Cij = {1 + cos2 [90 (Fbi – 2αij)/Fbi]}1/2

Vij = ω1 V sin αij + ω2 (L)1/2

ω1 = 0.515 (1.68) for m (ft)

ω2 = 1.0 (1.8) for m (ft)

V = as defined in 5C-5-3/5.1.1. V is not taken less than 10 knots.
γij = local bow angle measured from the horizontal, not to be taken less than 50°

= tan-1 (tan βij /cos αij)

αij = local waterline angle between the tangent line and the centerline, see
5C-5-3/Figure 11, not taken less than 35°
βij = local body plan angle measured from the horizontal, see 5C-5-3/Figure 11,
not taken less than 35°
Fbi = freeboard from the highest deck at side to the LWL at station i, in m (ft), see
5C-5-3/Figure 11
αij = vertical distance from the LWL to j-th WL, in m (ft), see 5C-5-3/Figure 11
Ck = 0.7 at collision bulkhead and 0.9 at 0.0125L aft of the FP, with linear
interpolation for intermediate locations
= 0.9 between 0.0125L aft of the FP and the FP
= 1.0 at and forward of the FP
i, j = station and waterline, to be taken to correspond to the locations as required
by the forward body strength requirements
L = vessel length, as defined in 3-1-1/3.1, in m (ft).
5.3.4(b) Green Water. When experimental data or direct calculation is not available, nominal
green water pressures imposed on deck in the region forward of 0.3L from the FP may be obtained
from the following equations. pgi is not to be taken less than 20.6 kN/m2 (2.1 tf/m2, 0.192 Ltf/ft2).

pgi = k Fn sin (δj)(MRi − k1Fbi)1/2 kN/m2 (tf/m2, Ltf/ft2)

where
k = 128.16 (13.063, 0.3584)
k1 = 1.5 (4.92) for m (ft)

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Section 3 Load Criteria 5C-5-3

Fn = Vd /(gL)1/2 ≥ 0.225, Vd is design speed as defined in 3-2-14/3, in m/s (ft/s)

Fbi = freeboard at station i, in m (ft)
MRi = as defined in 5C-5-3/11.1, if MRi < k1Fbi, then pgi = 0
δj = the angle between the horizontal and a line connecting the highest deck at the
side and the half beam at the still waterline of station i, see 5C-5-3/Figure 11
g = acceleration due to gravity = 9.807 m/sec2 (32.2 ft/sec2)

5.5 Cargo Loads and Liquid Pressure (1998)

5.5.1 Ship Motions and Accelerations
In determining the cargo loads and liquid pressure, the dominant ship motions, pitch and roll, and
the resultant accelerations induced by the wave are required. When a direct calculation is not
available, the approximate equations given below may be used:
5.5.1(a) Pitch. (1998) The pitch amplitude: (positive bow up)
φ = k1(V/Cb)1/4/L in deg.,
but need not to be taken more than 10 deg.
The pitch natural period:
Tp = k2 (Cb di)1/2 in sec.
where
k1 = 1030 (3378) for L, in m (ft)
k2 = 3.5 (1.932) for di, in m (ft)
V = as defined in 5C-5-3/5.1.1
di = draft amidships for the relevant loading conditions
The vessel length L is as defined in 3-1-1/3.1, in m (ft).
Cb is as defined in 3-2-1/3.5.1 and is not to be taken less than 0.6.
5.5.1(b) Roll. (1998) The roll amplitude: (positive starboard down)
θ = CR (28.4 − kθ Cdi Δ/1000) if Tr > 20 sec.

θ = CR (28.4 − kθ Cdi Δ/1000)(1.5375 − 0.027 Tr) if 12.5 ≤ Tr ≤ 20 sec.

θ = CR (28.4 − kθ Cdi Δ/1000) 1.2 if Tr < 12.5 sec.

where
kθ = 0.002 (0.02, 0.02)

θ, in degrees, but need not to be taken greater than 30 degrees.

CR = 1.0 − 0.00625V
V = as defined in 5C-5-3/5.1.1
Cdi = 1.25 (di /d) − 0.25
di = draft amidships for the relevant loading conditions, in m (ft)
d = draft as defined in 3-1-1/9, in m (ft)
Δ = k d Cb L B d kN (tf, Ltf)
kd = 10.05 (1.025, 0.0286)

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Section 3 Load Criteria 5C-5-3

L, B are as given in 3-1-1/3.1 and 3-1-1/5.

Cb is as defined in 3-2-1/3.5.1 and is not to be taken less than 0.6.
The roll natural motion period:
Tr = k4 kr /GM1/2 in sec.
where
k4 = 2 (1.104) for kr, GM in m (ft)
kr = roll radius of gyration, in m (ft), and may be taken as 0.35B for full load
conditions and 0.40B for 2/3 draft conditions.
GM = metacentric height, to be taken as:
= GM(full) for di = d
= 3.0 GM(full) for di = 2/3 d
GM(full) = metacentric height for fully loaded condition
If GM(full) is not available, GM(full) can be taken as 0.06B.
5.5.1(c) Accelerations (1 July 2005). The vertical, longitudinal and transverse accelerations of
tank contents (cargo or liquid), av, al and at may be obtained from the following formulae:

a v = Cv k v a o g m/sec2 (ft/sec2) positive downward

al = Cl kl ao g m/sec2 (ft/sec2) positive forward

at = Ct kt ao g m/sec2 (ft/sec2) positive starboard

where
ao = k0 (2.4/L1/2 + 34/L − 600/L2) for L in m

= k0 (4.347/L1/2 + 111.55/L − 6458/L2) for L in ft

k0 = (1.3 – 0.47Cb) for strength formulation and assessment of local structural
elements and members in Sections 5C-5-4 and 5C-5-5
= (1.09 + 0.029V − 0.47Cb) for fatigue strength formulation in 5C-5-5/7,
Appendix 5C-5-A1
V = as defined in 5C-5-3/5.1.1
Cb = as defined in 3-2-1/3.5.1 and is not to be taken less than 0.6

Cv = cos2 μ + (1 + 1.0 z/B) (sin μ)/kv

μ = wave heading angle in degrees, 0° for head sea, and 90° for beam sea for
wave coming from starboard
kv = [1 + 0.65(5.3 − 45/L)2 (x/L − 0.45)2]1/2 for L in m

= [1 + 0.65(5.3 − 147.6/L) 2 (x/L − 0.45)2]1/2 for L in ft

Cl = 0.35 − 0.0005 (L − 200) for L in m

= 0.35 − 0.00015 (L − 656) for L in ft

kl = 0.5 + 8y/L
Ct = 1.27[1 + 1.52(x/L − 0.45)2]1/2

kt = (0.35 + 0.5 y/B) sin μ

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Section 3 Load Criteria 5C-5-3

x = longitudinal distance from the AP to the station considered, in m (ft)

y = vertical distance from the waterline to the point considered, in m (ft),
positive upward
z = transverse distance from the centerline to the point considered in m (ft),
positive starboard
g = acceleration due to gravity = 9.807 m/sec2 (32.2 ft/sec2)
L, B are the length and breadth of vessel, as defined in 3-1-1/3.1 and 3-1-1/5, respectively, in m (ft).
5.5.2 Cargo Container Loads
5.5.2(a) General. For the design and evaluation of hull structure, the following forces due to the
loaded containers are to be considered:
• Static weight in upright condition
• Dynamic forces due to roll and pitch of vessel
• Inertial force due to acceleration.
For the design and evaluation of the hull structure, all containers are considered to be stowed by
stacks in the cargo hold and above the deck. All containers in the hold are to be restrained by cell
guides, which are a series of vertical steel angles, suitably spaced according to the container length and
width, which provide alignment and horizontal restraint for container stacks. The static and dynamic
forces due to loaded containers are to be applied to supporting structures, such as web, girders, pillars,
etc., as concentrated forces through the cell guide and to bottom corners of the container stack.
The container loads from the containers stored above the deck are to be applied to hatch coamings,
bulwark or other supporting structures at the bottom of the container stack.
5.5.2(b) Loads. The forces from individual containers are to be calculated at the center of gravity
of each container. The center of gravity of the container may be normally considered as the mid
point of the container.
Fv = W + ku Fdv kN (tf, Ltf)
Ft = ku Fdt kN (tf, Ltf)
Fl = ku Fdl kN (tf, Ltf)
where
Fv = vertical container load due to each container, positive downward
Ft = transverse container load due to each container, positive starboard
Fl = longitudinal container load due to each container, positive forward
W = gross weight of the container, in kN (tf, Ltf)
Fdv = dynamic vertical container load due to ship motion
= kc W [cos φe cos θe + ave /g − 1]
Fdt = dynamic transverse container load due to ship motion, positive starboard
= kc W [sin θe + ate /g]
Fdl = dynamic longitudinal container load due to ship motion, positive forward
= kc W [–sin φe + ale /g]
kc = correlation coefficient and may be taken as unity unless otherwise specified
ku = dynamic load factor and may be taken as unity unless otherwise specified
θe = effective angle of roll = 0.71 Cθθ

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Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 3 Load Criteria 5C-5-3

φe = effective angle of pitch = 0.71 Cφφ

ave = effective vertical acceleration = 0.71 cvav
ate = effective transverse acceleration = 0.71 cTat
ale = effective longitudinal acceleration = 0.71 cLal
cv, cT, cL, Cθ and Cφ are as specified in 5C-5-3/Table 1, 5C-5-3/Table 2 and 5C-5-A1/Table 3.
av, at, and al are as specified in 5C-5-3/5.5.1(c).

φ and θ are pitch and roll amplitudes, as given in 5C-5-3/5.5.1(a) and 5C-5-3/5.5.1(b).
The container loads Fv, Ft, and Fl may be distributed equally to the four corners of the container in
the direction of the load component, as shown in 5C-5-3/Figure 12. The transverse and longitudinal
container loads acting on the cell guide may be transmitted to supporting structural members by
statically distributing the loads to adjacent supporting points along the cell guide, as shown in
5C-5-3/Figure 13.
All vertical container loads are to be transmitted to the bottom corners of each container stack.
All container loads above the deck are to be transmitted to the bottom corners of each container
stack, and then distributed to supporting structures such as hatch coaming, bulwark or stanchions.
5.5.3 Internal Liquid Pressures
5.5.3(a) Distribution of Internal Pressures (1 July 2005). The internal liquid pressures, pi, positive
toward tank boundaries for a fully filled ballast or other tank may be obtained from the following
formula:
pi = ρ g(η + Δη + ku hd) ≥ 0 in N/cm2 (kgf/cm2, lbf/in2)
where
ρg = specific weight of the fluid in N/cm2-m (kgf/cm2-m, lbf/in2-ft), but not to be
taken less than the specific weight of sea water
η = local coordinate in vertical direction for tank boundaries measuring from the
top of the tank to the point considered, as shown in 5C-5-3/Figure 14, in m (ft)
Δη = 0 for the upper tank whose tank top extends to the strength deck
= a distance equivalent to 2/3 of the distance from tank top to the top of the
overflow (The exposed height is minimum 760 mm above freeboard deck or
450 mm above superstructure deck.) for the lower tank whose tank top does
not extend to the strength deck.
Where a side shell wing tank top extends to the underdeck passageway
(second deck), this distance need not be greater than 1/3 of the distance from
the second deck to the top of the overflow
ku = load factor and may be taken as unity unless otherwise specified.
hd = wave induced pressure head, including inertial force and added pressure head

= kc(ηai /g + Δhi), m (ft)

kc = correlation factor and may be taken as unity unless otherwise specified.
ai = effective resultant acceleration, in m/sec2 (ft/sec2), at the point considered,
may be approximated by 0.71Cdp[wv av + wl(l/h) al + wt(b/h)at]
g = acceleration due to gravity
= 9.807 m/sec2 (32.2 ft/sec2)
Cdp is specified in 5C-5-3/5.5.3(d).

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Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 3 Load Criteria 5C-5-3

av, al and at are as given in 5C-5-3/5.5.1(c).

wv, wl and wt are weighted coefficients, showing directions, as specified in 5C-5-3/Table 1,
5C-5-3/Table 2, and 5C-5-A1/Table 3.
Δhi = added pressure head due to pitch and roll motions at the point considered, in
m (ft).
In general, the added head may be calculated based on the vertical distance from the reference
point of the tank to the point considered. The reference point is (i) the highest point of the tank
boundary after roll and pitch, or (ii) the average height of the points after roll and pitch, which are
Δη above the top of the tank at the overflow, whichever is greater.
For prismatic tanks on the starboard side, whose tank top extends to the strength deck, the added
pressure head may be calculated as follows:
i) for bow down and starboard down (φe < 0, θe > 0)

Δhi = ξ sin(-φe) + Cru (ζe sin θe cos φe + ηe cos θe cos φe − η)

ζe = b − ζ
ηe = η
ii) for bow up and starboard up (φe > 0, θe < 0)

Δhi = (l – ξ)sin φe + Cru {ζe sin(-θe) cos φe + ηe cos θe cos φe − η}

ζe = ζ − δb
ηe = η − δh
Cru is specified in 5C-5-3/5.5.3(d).

ξ, ζ, η are the local coordinates, in m (ft), for the point considered with respect to the origin shown
in 5C-5-3/Figure 14; b and h are the local coordinate adjustments, in m (ft), for a rounded tank
corner, as shown in 5C-5-3/Figure 14.
where
θe = 0.71 Cθθ

φe = 0.71 Cφφ

l = length of the tank, in m (ft)

b = breadth of the tank considered, in m (ft)
h = height of the tank considered, in m (ft)
φ and θ are pitch and roll amplitudes, as given in 5C-5-3/5.5.1(a) and 5C-5-3/5.5.1(b).
Cφ and Cθ are weighted coefficients showing directions, as given in 5C-5-3/Table 1, 5C-5-3/Table 2
and 5C-5-A1/Table 3.
For prismatic lower tanks on starboard side whose tank top does not extend to the strength deck,
added pressure head may be calculated as follows, assuming the reference point based on the
average height of the overflow.
i) for bow down and starboard down (φe < 0, θe > 0)

Δhi = (ξ − l/2) sin (-φe) + Cru (ζe sin θe cos φe + ηe cos θe cos φe − ηe)

ζe = ba − ζ
ηe = η + Δη

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Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 3 Load Criteria 5C-5-3

ii) for bow up and starboard up (φe > 0, θe < 0)

Δhi = (l/2 − ξ) sin φe + Cru {ζe sin(-θe) cos φe + ηe cos θe cos φe − ηe}

ζe = ζ − ba
ηe = η + Δη
ba is the transverse distance of overflow from ξ axis. All other parameters are as defined above.
5.5.3(b) Extreme Internal Liquid Pressure. For assessing local structures at a tank boundary, the
extreme internal liquid pressure with ku, as specified in 5C-5-3/7, is to be considered.
5.5.3(c) Simultaneous Internal Liquid Pressures. In performing a structural analysis, the internal
liquid pressures may be calculated in accordance with 5C-5-3/5.5.3(a) and 5C-5-3/5.5.3(b) above
for tanks in the midbody. For tanks in the fore or aft body, the pressures are to be determined
based on linear distributions of accelerations and ship motions along the length of the vessel.
5.5.3(d) Definition of Tank Shape and Associated Coefficients
i) Rectangular Tank
The following tank is considered as a rectangular tank:
b/b1 ≤ 3.0 or h/h1 ≤ 3.0
where
b = extreme breadth of the tank considered
b1 = least breadth of wing tank part of the tank considered
h = extreme height of the tank considered
h1 = least height of double bottom part of the tank considered
as shown in 5C-5-3/Figure 14
The coefficients Cdp and Cru of the tank are as follows:
Cdp = 1.0
Cru = 1.0
ii) J-shaped Tank
A tank having the following configurations is considered as a “J-shaped” tank.
b/b1 ≥ 5.0 and h/h1 ≥ 5.0
The coefficients Cdp and Cru are as follows:
Cdp = 0.7
Cru = 1.0
iii) U-shaped Tank
A half of a “U-shaped” tank, divided at the centerline, should satisfy the condition of a “J-shaped” tank.
The coefficients Cdp and Cru are as follows:
Cdp = 0.5
Cru = 0.7
ai, defined in 5C-5-3/5.5.3(a), for U-shaped tank is not to be taken less than that calculated for
J-shaped tank.

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Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 3 Load Criteria 5C-5-3

iv) In a case where the minimum tank ratio of b/b1 or h/h1, whichever is lesser, is greater than
3.0 but less than 5.0, the coefficients Cdp and Cru of the tank are to be determined by the
following interpolation:
An intermediate tank between rectangular and J-shaped tank:
(Rectangular - J-shaped like tank)
Cdp = 1.0 − 0.15 (the min. tank ratio - 3.0)
Cru = 1.0
An intermediate tank between rectangular and U-shaped tank:
(Rectangular - U-shaped like tank)
Cdp = 1.0 − 0.25 (the min. tank ratio - 3.0)

Cru = 1.0 − 0.15 (the min. tank ratio - 3.0)

ai, defined in 5C-5-3/5.5.3(a), for a rectangular – “U” shape like tank is not to be taken less than
that calculated for a rectangular – “J” shape like tank.
v) For non-prismatic tanks mentioned in Note 4 of 5C-5-3/Table 2, b1, h and h1 are to be
determined based on the extreme section.

616 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 3 Load Criteria 5C-5-3

FIGURE 4
Distribution Factor mh (1998)

Distribution m h 1.0

0.0
0.0 0.4 0.6 1.0
Aft Forward
end of L end of L
Distance from the aft end of L in terms of L

FIGURE 5
Distribution Factor fh (1998)

1.0
Distribution f h

0.7

0.0
0.0 0.2 0.3 0.4 0.60 0.7 0.8 1.0
Aft Forward
end of L end of L
Distance from the aft end of L in terms of L

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 617
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 3 Load Criteria 5C-5-3

FIGURE 6
Distribution Factor mT (1998)

1.0

0.7
Distribution mT

0.0
0.0 0.15 0.55 0.65 0.9 1.0
Aft Forward
end of L end of L
Distance from the aft end of L in terms of L

FIGURE 7
Torsional Moment Distribution Curves (1998)

1.2

1.0
A B
0.8

0.6 C

0.4
Distribution mT

0.2

0.0
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
-0.2

-0.4

-0.6

-0.8

-1.0

-1.2
Distance from the aft end of L in terms of L

618 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 3 Load Criteria 5C-5-3

FIGURE 8
Distribution of Hydrodynamic Pressure (1998)
h = freeboard to W.L.

Freeboard Deck

hd5 hd1 W.L.

h or h*
whichever is lesser

hd4 h hd2
d3

View from the Stern

Note: h* = ku kc hd1 for nominal pressure

h* = kf ku hd1 for simultaneous pressure

FIGURE 9
Hydrodynamic Pressure Distribution Factor klo (1998)

2.5
Distribution klo

1.5

1.0

0.0
0.0 0.2 0.7 1.0
Aft Forward
end of L end of L
Distance from the aft end of L in terms of L

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 619
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 3 Load Criteria 5C-5-3

FIGURE 10
Illustration of Determining Total External Pressure

h
hd1

h or h*
whichever is lesser

hd : Hydrodynamic Pressure Head (indicates negative)

hs : Hydrostatic Pressure Head in Still Water

: Total External Pressure Head

Note: h* = ku kc hd1 for nominal pressure

h* = kf ku hd1 for simultaneous pressure

FIGURE 11
Definition of Bow Geometry (1 July 2008)

WLj A B

αij
waterline angle
tangent line

B A

CL

CL CL
highest
deck

Fbi tangent line tangent line

s
normal
body plan
angle βij body plan βij'
angle
WLj

aij
δj
LWL
A-A B-B

620 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 3 Load Criteria 5C-5-3

FIGURE 12
Distribution of Container Loads to Corners in Hold
1/4Fl
1/4Fl
1/4Ft
AFT
1/4Fl 1/4Fl
1/4Ft
RT
1/4Ft PO
OM 1/4Fv
1/4Fv
OTT
B

1/4Ft

1/4Fv 1/4Fv

FIGURE 13
Transfer of Container Corner Loads on the Cell Guide to Support Points

Support Point B

FB

b
b
FA = F
a+b
F
FB = a
F
a a+b

FA

Support Point A

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 621
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 3 Load Criteria 5C-5-3

FIGURE 14
Definition of Tank Geometry

ξ
F.P.

b1

h l

h1

Tank Shape Parameters ζ O

b

B/2
L
C
Plan View
δb ξ

δb δh
l δh
O
ζ

ζ O

b
η
B/2 Elevation
L
C

η
Isometric View

622 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
 TABLE 1A
Part

Combined Load Cases for Yielding and Buckling Strength Formulation (2007)
Section
Chapter

L.C. 1 L.C. 2 L.C. 3 L.C. 4 L.C. 5 L.C. 6 L.C. 7 L.C. 8 L.C. 9 L.C. 10
(2)
A. Hull Girder Loads
Vertical B.M.(3) Sag (–) Hog (+) Sag (–) Hog (+) Sag (–) Hog (+) Sag (–) Hog (+) Sag (–) Hog (+)
kc 1.0 1.0 0.7 0.7 0.3 0.3 0.4 0.4 0.4 0.4
Vertical S.F. (+) (–) (+) (–) (+) (–) (+) (–) (–) (+)
kc 0.5 0.5 1.0 1.0 0.3 0.3 0.4 0.4 0.4 0.4
3 Load Criteria

Horizontal B.M Stbd Tens (–) Port Tens (+) Stbd Tens (–) Port Tens (+) Port Tens (+) Stbd Tens (–)
kc 0.0 0.0 0.0 0.0 0.3 0.3 0.5 0.5 0.7 0.7
Horizontal S.F. (+) (–) (+) (–) (–) (+)
5C Specific Vessel Types

kc 0.0 0.0 0.0 0.0 1.0 1.0 0.5 0.5 0.7 0.7
Torsional Mt.(4) (–) (+) (–) (+) (–) (+)
kc 0.0 0.0 0.0 0.0 0.55αs 0.55αs αs αs αs αs
B. External Pressure
kc 0.5 0.5 0.5 1.0 0.5 1.0 0.5 1.0 0.5 1.0
kfo -1.0 1.0 -1.0 1.0 -1.0 1.0 -1.0 1.0 1.0 -1.0
C. Container Cargo Load

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

kc 0.4 0.4 1.0 0.5 1.0 0.5 1.0 0.5 1.0 0.5
Cv 0.8 -0.8 0.8 -0.8 0.4 -0.4 0.7 -0.7 -0.7 0.7
CL Fwd Bhd Fwd Bhd Fwd Bhd Fwd Bhd -- -- Fwd Bhd Fwd Bhd Fwd Bhd Fwd Bhd
0.6 0.0 0.6 0.0 -- -- 0.7 0.0 0.0 0.7
Aft Bhd Aft Bhd Aft Bhd Aft Bhd Aft Bhd Aft Bhd Aft Bhd Aft Bhd
0.0 -0.6 0.0 -0.6 0.0 -0.7 -0.7 0.0
CT -- -- -- -- Port Wall Port Wall Port Wall Port Wall Port Wall Port Wall
-- -- -- -- 0.0 -0.9 0.0 -0.7 -0.7 0.0
Stbd Wall Stbd Wall Stbd Wall Stbd Wall Stbd Wall Stbd Wall
0.9 0.0 0.7 0.0 0.0 0.7
Cφ, Pitch -0.35 0.35 -0.70 0.70 0.0 0.0 -0.30 0.30 0.30 -0.30
Cθ, Roll 0.0 0.0 0.0 0.0 1.0 -1.0 0.30 -0.30 -0.30 0.30
5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)

623
5C-5-3
 TABLE 1A (continued)

624
Part

Combined Load Cases for Yielding and Buckling Strength Formulation (2007) Section
Chapter

L.C. 1 L.C. 2 L.C. 3 L.C. 4 L.C. 5 L.C. 6 L.C. 7 L.C. 8 L.C. 9 L.C. 10
D. Internal Ballast Tank Pressure
kc 0.4 0.4 1.0 0.5 1.0 0.5 1.0 0.5 1.0 0.5
wv 0.75 -0.75 0.75 -0.75 0.25 -0.25 0.4 -0.4 -0.4 0.4
wl Fwd Bhd Fwd Bhd Fwd Bhd Fwd Bhd -- -- Fwd Bhd Fwd Bhd Fwd Bhd Fwd Bhd
0.25 -0.25 0.25 -0.25 -- -- 0.2 -0.2 -0.2 0.2
3 Load Criteria

Aft Bhd Aft Bhd Aft Bhd Aft Bhd Aft Bhd Aft Bhd Aft Bhd Aft Bhd
-0.25 0.25 -0.25 0.25 -0.2 0.2 0.2 -0.2
wL -- -- -- -- Port Wall Port Wall Port Wall Port Wall Port Wall Port Wall
5C Specific Vessel Types

-- -- -- -- -0.75 0.75 -0.4 0.4 0.4 -0.4

Stbd Wall Stbd Wall Stbd Wall Stbd Wall Stbd Wall Stbd Wall
0.75 -0.75 0.4 -0.4 -0.4 0.4
Cφ, Pitch -0.35 0.35 -0.70 0.70 0.0 0.0 -0.30 0.30 0.30 -0.30
Cθ, Roll 0.0 0.0 0.0 0.0 1.0 -1.0 0.30 -0.30 -0.30 0.30
E. Reference Wave Heading and Position
Heading 0 0 0 0 90 90 60 60 60 60
Angle
Heave Down Up Down Up Down Up Down Up Up Down
Pitch Bow Down Bow Up Bow Down Bow Up -- -- Bow Down Bow Up Bow Up Bow Down
Roll -- -- -- -- Stbd Down Stbd Up Stbd Down Stbd Up Stbd Up Stbd Down
Draft 2/3 1 2/3 1 2/3 2/3 2/3 1 2/3 1

1 ku = 1.0 for all load components.

2 Boundary forces are to be applied to produce the above specified hull girder bending moment at the middle of the structural model, and specified hull girder shear force at one
end of the middle hold of the model. The sign convention for the shear force corresponds to the forward end of middle hold. The specified torsional moment is to be produced at
the aft bulkhead of the middle hold for L.C. 5-8, and at the forward bulkhead of the middle hold for L.C. 9-10.
3 (1 July 2005) The following still water bending moment (SWBM) is to be used for structural analysis.
L.C. 1, 3, 5, 7 and 9: Minimum hogging SWBM amidships of the actual container cargo loading conditions. This SWBM is not be more than 20% of the wave-induced sagging
moment.
5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)

L.C. 2, 4, 6, 8 and 10: Maximum hogging SWBM.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

5C-5-3
 TABLE 1A (continued)
Part

Combined Load Cases for Yielding and Buckling Strength Formulation (2007)
Section
Chapter

4 (1999) αs is to be obtained by the following equation:

αs = (Tm + Ts)/Tm
where
Tm = nominal wave-induced torsional moment amidships, in kN-m (tf-m, Ltf-ft), as defined in 5C-5-3/5.1.5(a)
Ts = still-water torsional moment amidships, in kN-m (tf-m, Ltf-ft), as defined in 5C-5-3/3.1
3 Load Criteria

5 (2007) For the lower tanks whose tank top does not extend to the second deck, Δη is to be the distance equivalent to 1/2 of the distance from the tank top to the top of the overflow
(the exposed height is minimum 760 mm above the freeboard deck or 450 mm above the superstructure deck). However, Δη need not be greater than the distance between the
tank top and second deck.
5C Specific Vessel Types

6 (2007) L.C. 9 & 10 are applicable to the structural model representing the cargo hold immediately forward of the engine room.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)

625
5C-5-3
 TABLE 1B

626
Part

Combined Load Cases for Fatigue Strength Formulation (2007) Section

Chapter

L.C. 1 L.C. 2 L.C. 3 L.C. 4 L.C. 5 L.C. 6 L.C. 7 L.C. 8 L.C. 9 L.C. 10
(2)
A. Hull Girder Loads
Vertical B.M.(3) Sag (–) Hog (+) Sag (–) Hog (+) Sag (–) Hog (+) Sag (–) Hog (+) Sag (–) Hog (+)
kc 1.0 1.0 0.7 0.7 0.3 0.3 0.4 0.4 0.4 0.4
Vertical S.F. (+) (–) (+) (–) (+) (–) (+) (–) (–) (+)
kc 0.5 0.5 1.0 1.0 0.3 0.3 0.4 0.4 0.4 0.4
3 Load Criteria

Horizontal B.M Stbd Tens (–) Port Tens (+) Stbd Tens (–) Port Tens (+) Port Tens (+) Stbd Tens (–)
kc 0.0 0.0 0.0 0.0 0.3 0.3 0.5 0.5 0.7 0.7
Horizontal S.F. (+) (–) (+) (–) (–) (+)
5C Specific Vessel Types

kc 0.0 0.0 0.0 0.0 1.0 1.0 0.5 0.5 0.7 0.7
Torsional Mt.(4) (–) (+) (–) (+) (–) (+)
kc 0.0 0.0 0.0 0.0 0.55αs 0.55αs αs αs αs αs
B. External Pressure
kc 0.5 0.5 0.5 1.0 0.5 1.0 0.5 1.0 0.5 1.0
kfo -1.0 1.0 -1.0 1.0 -1.0 1.0 -1.0 1.0 1.0 -1.0
C. Container Cargo Load
kc 0.4 0.4 1.0 0.5 1.0 0.5 1.0 0.5 1.0 0.5
Cv 0.8 -0.8 0.8 -0.8 0.4 -0.4 0.7 -0.7 -0.7 0.7
CL Fwd Bhd Fwd Bhd Fwd Bhd Fwd Bhd -- -- Fwd Bhd Fwd Bhd Fwd Bhd Fwd Bhd
0.6 0.0 0.6 0.0 -- -- 0.7 0.0 0.0 0.7
Aft Bhd Aft Bhd Aft Bhd Aft Bhd Aft Bhd Aft Bhd Aft Bhd Aft Bhd
0.0 -0.6 0.0 -0.6 0.0 -0.7 -0.7 0.0
CT -- -- -- -- Port Wall Port Wall Port Wall Port Wall Port Wall Port Wall
-- -- -- -- 0.0 -0.9 0.0 -0.7 -0.7 0.0
Stbd Wall Stbd Wall Stbd Wall Stbd Wall Stbd Wall Stbd Wall
0.9 0.0 0.7 0.0 0.0 0.7
Cφ, Pitch -1.0 1.0 -1.0 1.0 0.0 0.0 -0.7 0.7 0.7 -0.7
Cθ, Roll 0.0 0.0 0.0 0.0 1.0 -1.0 0.7 -0.7 -0.7 0.7
5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

5C-5-3
 TABLE 1B (continued)
Part

Combined Load Cases for Fatigue Strength Formulation (2007)

Section
Chapter

L.C. 1 L.C. 2 L.C. 3 L.C. 4 L.C. 5 L.C. 6 L.C. 7 L.C. 8 L.C. 9 L.C. 10
D. Internal Ballast Tank Pressure
kc 0.4 0.4 1.0 0.5 1.0 0.5 1.0 0.5 1.0 0.5
wv 0.75 -0.75 0.75 -0.75 0.25 -0.25 0.4 -0.4 -0.4 0.4
wl Fwd Bhd Fwd Bhd Fwd Bhd Fwd Bhd -- -- Fwd Bhd Fwd Bhd Fwd Bhd Fwd Bhd
0.25 -0.25 0.25 -0.25 -- -- 0.2 -0.2 -0.2 0.2
3 Load Criteria

Aft Bhd Aft Bhd Aft Bhd Aft Bhd Aft Bhd Aft Bhd Aft Bhd Aft Bhd
-0.25 0.25 -0.25 0.25 -0.2 0.2 0.2 -0.2
wL -- -- -- -- Port Wall Port Wall Port Wall Port Wall Port Wall Port Wall
5C Specific Vessel Types

-- -- -- -- -0.75 0.75 -0.4 0.4 0.4 -0.4

Stbd Wall Stbd Wall Stbd Wall Stbd Wall Stbd Wall Stbd Wall
0.75 -0.75 0.4 -0.4 -0.4 0.4
Cφ, Pitch -1.0 1.0 -1.0 1.0 0.0 0.0 -0.7 0.7 0.7 -0.7
Cθ, Roll 0.0 0.0 0.0 0.0 1.0 -1.0 0.7 -0.7 -0.7 0.7
E. Reference Wave Heading and Position
Heading 0 0 0 0 90 90 60 60 60 60

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

Angle
Heave Down Up Down Up Down Up Down Up Up Down
Pitch Bow Down Bow Up Bow Down Bow Up -- -- Bow Down Bow Up Bow Up Bow Down
Roll -- -- -- -- Stbd Down Stbd Up Stbd Down Stbd Up Stbd Up Stbd Down
Draft 2/3 1 2/3 1 2/3 2/3 2/3 1 2/3 1

1 ku = 1.0 for all load components.

2 Boundary forces are to be applied to produce the above specified hull girder bending moment at the middle of the structural model, and specified hull girder shear force at one
end of the middle hold of the model. The sign convention for the shear force corresponds to the forward end of middle hold. The specified torsional moment is to be produced at
the aft bulkhead of the middle hold for L.C. 5-8, and at the forward bulkhead of the middle hold for L.C. 9-10.
3 The following still water bending moment (SWBM) is to be used for structural analysis.
L.C. 1, 3, 5, 7 and 9: Minimum hogging SWBM amidships of the actual container cargo loading conditions. This SWBM is not be more than 20% of the wave-induced sagging
moment.
5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)

L.C. 2, 4, 6, 8 and 10: Maximum hogging SWBM.

627
5C-5-3
 TABLE 1B (continued)

628
Part

Combined Load Cases for Fatigue Strength Formulation (2007) Section

Chapter

4 αs is to be obtained by the following equation:

αs = (Tm + Ts)/Tm
where
Tm = nominal wave-induced torsional moment amidships, in kN-m (tf-m, Ltf-ft), as defined in 5C-5-3/5.1.5(a)
Ts = still-water torsional moment amidships, in kN-m (tf-m, Ltf-ft), as defined in 5C-5-3/3.1
3 Load Criteria

5 For the lower tanks whose tank top does not extend to the second deck, Δη is to be the distance equivalent to 1/2 of the distance from the tank top to the top of the overflow (the
exposed height is minimum 760 mm above the freeboard deck or 450 mm above the superstructure deck). However, Δη need not be greater than the distance between the tank
top and second deck.
5C Specific Vessel Types

6 L.C. 9 & 10 are applicable to the structural model representing the cargo hold immediately forward of the engine room.
5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

5C-5-3
 TABLE 2
Part

Design Pressure for Local and Supporting Members (2007)

Section
Chapter

A. Local Structures - Plating & Long’ls/Stiffeners

The nominal pressure (4, 5), p = ⏐pi – pe⏐, is to be determined from load cases “a” & “b” below, whichever is greater, with ku = 1.1 and kc = 1.0 unless otherwise specified in the
table (1)
Case “a” At Forward end of the tank or hold Case “b” At Forward end of the tank or hold
(2, 3) Coefficients Coefficients
Structural Members/ Draft/Wave Location and Draft/Wave Location (2, 3) and
Components Heading Angle Loading Pattern pi pe Heading Angle Loading Pattern pi pe
3 Load Criteria

1. Bottom Plating and Long‘l 2/3draft/0° Full double bottom & wing tanks Ai Ae Full draft/0° Empty double bottom & wing -- Be
tanks
2. Inner Bottom Plating and 2/3 draft/0° Full double bottom & wing tanks, Ai -- --
5C Specific Vessel Types

Long’l cargo holds empty

3. Side Shell Plating & 2/3 draft/60° Starboard side (6) of full double Bi Ae Full draft/60° Empty double bottom & wing -- Be
Long’l/Frame bottom & wing tank tanks
4. Main Deck Plating & Long’l 2/3 draft/0° Full wing tank (7) Ci --
5. Long’l Bulkhead Plating & 2/3 draft/60° Starboard side (6) of full double Bi -- Flooded Flooded (8) cargo hold, double Di --
long’l/Stiffeners bottom & wing tanks, cargo hold Condition bottom & wing tanks empty
empty

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

6. Transverse Bulkhead Plating
& Stiffeners
(i) Tank Boundaries 2/3 draft/0° Forward Bulkhead of full double Ai
bottom & wing tanks
(ii) Cargo Hold Boundaries Flooded Flooded (8) cargo hold Di
Condition
7. Double Bottom Structure
(i) Watertight Girder 2/3 draft/60° Starboard side (6) of full double Bi
Plating & Stiffeners bottom or wing tanks, adjacent
tanks empty
(ii) Tank End Floor Plating 2/3 draft/0° Forward tank end floor of full Ai
& Stiffeners double bottom or side tank,
adjacent tanks empty
8. Watertight Side Stringer 2/3 draft/60° Full double bottom or side tank, Bi
5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)

adjacent tanks empty

629
5C-5-3
 TABLE 2 (continued)

630
Part

Design Pressure for Local and Supporting Members (2007) Section

Chapter

B. Main Supporting Members

The nominal pressure, p = ⏐pi – pe⏐, is to be determined from load cases “a” & “b” below, whichever is greater, with ku = 1.0 and kc = 1.0 unless otherwise specified in the table
Case “a” Mid-Tank Case “b” Mid-Tank
Structural Members/ Draft/Wave Location and Coefficients Draft/Wave Location and Coefficients
Components Heading Angle Loading Pattern pi pe Heading Angle Loading Pattern pi pe
3 Load Criteria

9. Double Bottom Floors & Full draft/0° Mid-tank, cargo holds and ballast --- Be
Girders Bottom Transverse tanks empty
in Pipe Duct Space
10. Transverses and Stringers Full draft/90° Starboard side of mid-tank, cargo --- Be
5C Specific Vessel Types

hold and ballast tanks empty

11. Horizontal Girders and Flooded Flooded (8) cargo hold Di
Vertical Webs on Transverse Condition
Watertight Bulkhead
12. Transverse Webs on Flooded Flooded (8) cargo hold, double Di
Longitudinal Watertight Condition bottom & wing tanks empty
Bulkhead
13. Deck Transverse 2/3 draft/0° Full wing tank (7) Ci
14. Vertical Web on Double 2/3 draft/60° Starboard side (6) of full double Bi
Bottom Watertight Girder bottom or wing tanks, adjacent
tanks empty
5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

5C-5-3
 TABLE 2 (continued)
Part

Design Pressure for Local and Supporting Members (2007)

Section
Chapter

Notes:
1 For calculating pi and pe, the necessary coefficients are to be determined based on the following designated groups:
a) for pi

wl wt
wv Forward Bulkhead AFt Bulkhead Starboard side Port side Cφ Cθ
3 Load Criteria

Ai 0.75 0.25 -0.25 0.0 0.0 -0.35 0.0

Bi 0.40 0.20 -0.20 0.4 -0.4 -0.30 0.30
Ci -0.75 0.25 -- 0.0 0.0 -0.35 0.0
0.0 0.0 0.0 0.0 0.0 0.0 0.0
5C Specific Vessel Types

Di

b) for pe
Ae: klo = 1.0, ku = 1.0, kc = - 0.5
Be: klo = 1.0
2 For structures within 0.4L amidships, the nominal pressure is to be calculated for a hold or tank located amidships.
The net scantlings of the structural members within 0.4L amidships are to be determined for each cargo hold or tank in the region, based on the assumption that the cargo hold or

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

tank is located amidships as shown 5C-5-3/Figure 15.
3 For structures outside 0.4L amidships, the nominal pressure is to be calculated for members in a hold or tank under consideration.
4 The nominal pressure of a non-prismatic tank is to be calculated based on the extreme tank boundary section which is assumed constant lengthwise as illustrated in 5C-5-3/Figure
16. This calculated pressure is not applicable to members outside the actual tank boundary.
5 In calculation of the nominal pressure, ρg of the liquid or ballast is not to be taken less than 1.005 N/cm2-m (0.1025 kgf/cm2-m, 0.4444 lbf./in2-ft).
6 “Starboard side” and “Port side” designate the desired half portion of the tank, respectively. When calculating the nominal pressure for case a of item 5 and 11, the pressure at the
other half portion of the tank is to be examined.
7 The nominal deck pressure is to be not less than 2.06 N/cm2 (0.21 kgf/cm2, 2.99 lbf/in2) in Position 1 and 1.57 N/cm2 (0.16 kgf/cm2, 2.28 lbf/in2) in Position 2. Position 1 and
Position 2 are defined in 3-2-15/3 of the Rules.
8 (1 July 2005) The nominal pressure for watertight requirement for flooding condition may be taken as the cargo hold filled up to the deepest equilibrium waterline in the one
compartment damaged condition. This is not to be less than the cargo hold filled up to the bulkhead deck at center unless a deck lower than the uppermost continuous deck is
designed as freeboard deck, as allowed in 3-1-1/13.1. In such case, the nominal pressure may be taken as the cargo hold filled up to freeboard deck at center.
5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)

9 Application items for typical sections are illustrated in 5C-5-3/Figure 17. See also Note 6 for members marked with (*).

631
5C-5-3
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 3 Load Criteria 5C-5-3

FIGURE 15
Location of Hold for Nominal Pressure Calculation

5
Hold or Tank considered

5 4 3 2 1
FP
AP 0.4L

FIGURE 16
Nominal Pressure Calculation Procedure for Non-Prismatic Tank

Obtain the extreme

boundary section of a tank

Assume the extreme boundary

section is constant along the
tank's length.

Calculated pressure is not

applicable to members outside
the actual tank

632 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 3 Load Criteria 5C-5-3

FIGURE 17
Applicable Areas of Design Pressures
4

Passage way

(6(ii))

5b

3
Type A

5a (*)
(6(i))

8
2

7(i)
7(i)
7(ii) 7(ii)

Passage way

(6(ii))

5b

3
Type B
5a (*)

(6(i))

2
8
7(i)
7(i)

(7(ii)) (7(ii))

Passage way

(6(ii))
(6(i))
5b

Type C
3
5a (*)

8
2 (6(i))
7(i)
7(i)

(7(ii)) (7(ii))

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 633
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 3 Load Criteria 5C-5-3

7 Nominal Design Loads (1998)

The nominal design loads specified below are to be used for determining the required scantlings of hull
structures in conjunction with the specified permissible stresses given in Section 5C-5-4.

7.1 Hull Girder Loads – Longitudinal Bending Moments, Shear Forces and Torsional
Moment (1998)
7.1.1 Total Vertical Bending Moment and Shear Force
The total longitudinal vertical bending moment and shear force may be obtained from the following
equations:
Mt = Ms + ku kc Mw kN-m (tf-m, Ltf-ft)
Ft = Fs + ku kc Fw kN (tf, Ltf)
where
Ms and Mw are the stillwater bending moment and vertical wave-induced bending moment,
respectively, as specified in 5C-5-3/3.1 and 5C-5-3/5.1, for either hogging or sagging conditions.
Fs and Fw are the stillwater and the vertical wave-induced shear forces, respectively, as obtained
from 5C-5-3/3.1 and 5C-5-3/5.1 for either positive or negative shears.
ku is a load factor and may be taken as unity unless otherwise specified.
kc is a correlation factor and may be taken as unity unless otherwise specified.
The total bending moment is to be obtained based on the envelope curves, as specified in
5C-5-3/3.1 and 5C-5-3/5. For this purpose, ku = 1.0, and kc = 1.0.

7.1.2 Horizontal Wave Bending Moment and Shear Force

For non-head sea conditions, the horizontal wave bending moment and the horizontal shear force,
as specified in 5C-5-3/5.1, are to be considered as additional hull girder loads, especially for the
design of the side shell and inner skin structures within the range of 0.35D above and below the
mid-depth of vessel. The effective horizontal bending moment and shear force, MHE and FHE, may
be determined by the following equations:
MHE = ku kc MH kN-m (tf-m, Ltf-ft)
FHE = ku kc FH kN (tf, Ltf)
MH and FH are as specified in 5C-5-3/5.1.

7.1.3 Wave-Induced Torsional Moment

The effective wave-induced torsional moment for non-head sea conditions is to be considered in
addition to the hull girder loads specified in 5C-5-3/7.1.1 and 5C-5-3/7.1.2 above.
TME = ku kc TM kN-m (tf-m, Ltf-ft)
where
TM is as specified in 5C-5-3/5.1.5.
where ku and kc are load factor and correlation factor, respectively, which may be taken as unity
unless otherwise specified. For this purpose, ku = 1.0 and kc = 1.0.

7.3 Local Loads for Design of Supporting Structures (1998)

In determining the required scantlings of the main supporting structures, such as girders, transverses, stringers,
floors and deep webs, the nominal loads induced by the external pressures, ballast pressures and cargo loads
distributed over both sides of the structural panel within the cargo hold boundaries are to be considered for
the worst possible load combinations. In general, consideration is to be given to the following two loading
cases accounting for the worst effects of the dynamic load components.

634 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 3 Load Criteria 5C-5-3

7.3.1
Maximum internal cargo loads or pressures for a fully loaded cargo hold with the adjacent holds
empty and minimum external pressures, where applicable.
7.3.2
Empty cargo hold with the fore and aft holds full and maximum external pressures, where applicable.
The specified design loads for main supporting structures are given in 5C-5-3/Table 2.

7.5 Local Pressures for Design of Plating and Longitudinals (1998)

In calculating the required scantlings of plating, longitudinals and stiffeners, the nominal pressures are to
be considered for the two load cases given in 5C-5-3/7.3, using ku = 1.1 instead of ku = 1.0, as shown above.
The necessary details for calculating the nominal pressures are given in 5C-5-3/Table 2.

9 Combined Load Cases

9.1 Combined Load Cases for Structural Analysis (1998)

For assessing the strength of the hull girder structures and in performing a structural analysis as outlined in
Section 5C-5-5, the ten combined load cases specified in 5C-5-3/Table 1 are to be considered. Additional
combined load cases may be required as warranted. The loading patterns are shown in 5C-5-3/Figure 3 for
three cargo hold lengths. It is to be noted that the midship section should be located within the mid-hold of
the three hold FE model. The necessary factors and coefficients for calculating hull girder and local loads
are given in 5C-5-3/Table 1. The total external pressure distribution including static and hydrodynamic
pressures is illustrated in 5C-5-3/Figure 10.
If deemed necessary, another three hold length model consisting of the engine room and two adjacent
cargo holds forward is to be analyzed to assess the torsional response of the deck structures immediately
forward of the engine room. For this purpose, four load cases, Load Cases 7 through 10 of 5C-5-3/Table 1,
are to be considered using the loading patterns of cargo holds specified in 5C-5-3/Figure 3.

9.3 Combined Load Cases for Strength Assessment (1998)

For assessing the failure modes with respect to material yielding, buckling and ultimate strength, the
following combined load cases are to be considered:
9.3.1 Ultimate Strength of Hull Girder
For assessing ultimate strength of the hull girder, the combined effects of the following primary
and local loads are to be considered.
9.3.1(a) Primary Loads, Longitudinal Bending Moments and Shear Forces in Head Sea Conditions
(MH = 0, FH = 0, TM = 0)
Mt = Ms + ku kc Mw , kc = 1.0 hogging and sagging
Ft = Fs + ku kc Fw , kc = 1.0 positive and negative
ku = 1.15 for vessels without bowflare
For vessels having significant bowflare, ku is to be increased as specified in 5C-5-3/11.3.3.
Ms, Mw, Fs and Fw are as defined in 5C-5-3/3 and 5C-5-3/5.
9.3.1(b) Local loads for large stiffened panels. Internal and external pressure loads as given in
5C-5-3/Table 2 are to be considered.
9.3.2 Yielding, Buckling and Ultimate Strength of Local Structures
For assessing the yielding, buckling and ultimate strength of local structures, the ten combined
load cases given in 5C-5-3/Table 1 are to be considered.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 635
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 3 Load Criteria 5C-5-3

9.3.3 Fatigue Strength

For assessing the fatigue strength of structural joints, the ten combined load cases given in 5C-5-3/9.1
and two additional load cases given in 5C-5-A1/Table 3 are to be used for fatigue strength assessment,
as described in Appendix 5C-5-A1.

11 Impact Loads

11.1 Bottom Slamming Pressure (2002)

For container carriers with a heavy ballast draft forward less than 0.04L, bottom slamming loads are to be
considered for assessing strength of the flat of bottom plating forward and the associated stiffening system
in the fore body region.
The equivalent bottom slamming pressure for the strength assessment is to be determined based on well
documented experimental data or analytical studies. When these direct calculations are not available, nominal
bottom slamming pressures may be determined by the following equations:
Psi = k ki [v02 + MVi Eni] Ef kN/m2 (tf/m2, Ltf/ft2)
where
Psi = equivalent bottom slamming pressure for section i
k = 1.025 (0.1045, 0.000888)
ki = 2.2 b*/d0 + α ≤ 40

b* = half width of flat of bottom at the i-th ship station, see 5C-5-3/Figure 18
d0 = 1/
10 of the section draft at the heavy ballast condition, see 5C-5-3/Figure 18

α = a constant as given in 5C-5-3/Table 3

Ef = f1 ω1 (L)1/2
f1 = 0.004 (0.0022), m (ft)
ω1 = natural angular frequency of the hull girder 2-node vertical vibration of the vessel in
the wet mode and the heavy ballast draft condition, in rad/second. If not known, the
following equation may be used:
= μ[B D3/(ΔS Cb3 L3)]1/2 + 1.0 ≥ 3.7
μ = 23400 (7475, 4094)
ΔS = Δb[1.2 + B/(3db)]
Δb = vessel displacement at the heavy ballast condition, in kN (tf, Ltf)
db = mean draft of vessel at the heavy ballast condition, in m (ft)
V = 75% of design speed, Vd, in knots. V is not to be taken less than 10 knots.
Vd = the design speed as defined in 3-2-14/3

v0 = c0 L1/2, m/s (ft/s)

c0 = 0.29 (0.525), m (ft)
L = vessel’s length, as defined in 3-1-1/3.1, in m (ft)
Eni = natural log of ni

ni = 5730 (MVi /MRi)1/2 Gei, if ni < 1 then Psi = 0

636 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 3 Load Criteria 5C-5-3

2 2
Gei = e[-(v0 /M vi + di /M Ri )]
di = local section draft, in m (ft)
MVi = Bi MRi

MRi = c1 Ai (VL/Cb)1/2
c1 = 0.44 (2.615), m (ft)
Ai and Bi are as given in 5C-5-3/Table 4.
Cb is as defined in 3-2-1/3.5.1 and is not to be less than 0.6.
where b represents the half breadth at the 1/10 draft of the section, see 5C-5-3/Figure 18. Linear interpolation
may be used for intermediate values.

11.3 Bowflare Slamming

Bowflare slamming loads are to be considered for assessing the strength of the side plating and the
associated stiffening system in the forebody region of the vessel at its load waterline.
11.3.1 Nominal Bowflare Slamming (1 July 2008)
When experimental data or direct calculation is not available, nominal bowflare slamming pressures
above the load waterline (LWL) may be determined by the following equations:
Pij = P0ij or Pbij as defined below, whichever is greater

P0ij = k1(9MRi − hij2)1/2 kN/m2 (tf/m2, Ltf/ft2)

Pbij = k2 k3{c2 + Kij MVi (1 + Eni)} kN/m2 (tf/m2, Ltf/ft2)

where
k1 = 9.807 (1, 0.0278)
k2 = 1.025 (0.1045, 0.000888)

k3 = 1 for hij ≤ hb*

= 1 + (hij/ hb* – 1)2 for hb* < hij < 2hb*

= 2 for hij ≥ 2 hb*

c2 = 39.2 (422.46) for m (ft)
Eni = natural log of nij

nij = 5730 (MVi/MRi)1/2 Gij ≥ 1.0

Gij = exp (-hij2/MRi)

Mvi = Bi MRi, where Bi is given in 5C-5-3/Table 4

MRi = c1 Ai (VL/Cb)1/2, where Ai is given in 5C-5-3/Table 4, if 9MRi < hij2, then Poij = 0
c1 = 0.44 (2.615) for m (ft)
hij = vertical distance measured from the load waterline (LWL) at station i to WLj on
the bowflare. The value of hij is not to be taken less than hb* . Pbij at a location
between LWL and hb* above LWL need not be taken greater than pbij *
.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 637
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 3 Load Criteria 5C-5-3

hb* = 0.005(L – 130) + 3.0 (m) for L < 230 m

= 0.005(L – 426.4) + 9.84 (ft) for L < 754 ft
= 7.143 × 10 (L – 230) + 3.5 (m)
-3
for 230 m ≤ L < 300 m
= 7.143 × 10-3(L – 754.4) +11.48 (ft) for 754 ft ≤ L < 984 ft
= 4.0 m (13.12 ft) for L ≥ 300 m (984 ft)
*
pbij = Pbi* β i* β ij′

P *bi = Pbij at hb* above LWL

Kij = fij [rj/(bbij + 0.5hij)]3/2 [lij/rj ] [1.09 + 0.029V − 0.47 Cb] 2
rj = (MRi) 1/2
bbij = bij − bi0 > 2.0 m (6.56 ft)
bij = local half beam of location j at station i
bi0 = load waterline half beam at station i
lij = longitudinal distance of station i at j-th WL measured from amidships, based
on the scantling length
fij = [90/ β ij′ − 1]2 [tan2 ( β ij′ )/9.86] cos γ

β ij′ = normal local body plan angle

= tan-1[tan(βij)/cos(αij)]
αij = waterline angle as in 5C-5-3/Figure 11
βij = local body plan angle, in degrees, measured from the horizontal, as in
5C-5-3/Figure 11, not to be taken greater than 75 degrees

β i* = β ij′ at hb* above LWL

γ = ship stem angle at the centerline plane measured from the horizontal, as in
5C-5-3/Figure 19, in degrees, not to be taken greater than 75 degrees.
V = as defined in 5C-5-3/11.1
L = as defined in 3-1-1/3.1, in m (ft)
Cb = as defined in 3-2-1/3.5.1 and not to be less than 0.6.

11.3.2 Simultaneous Bowflare Slamming Pressure

For performing structural analyses to determine overall responses of the hull structures, the spatial
distribution of instantaneous bowflare pressures on the fore body region of the hull may be
expressed by multiplying the calculated maximum bowflare slamming pressures, Pij, at forward
ship stations by a factor of 0.71 for the region between the stem and 0.3L from the FP.
11.3.3 Effects of Bowflare Slamming on Vertical Hull Girder Bending Moment and Shear Force
(1 July 2005)
For container carriers having a forebody parameter, Ar dk, greater than 70 m2 (753 ft2), the buckling
strength of the hull girder structure in the forward half-length is to be evaluated using the
following hull girder bending moment and shear force.
The still water bending moment used to calculate the total bending moment may be determined
from the minimum hogging bending moment or maximum sagging bending moment, whichever is
applicable in the container cargo loading conditions.

638 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 3 Load Criteria 5C-5-3

The maximum bending moment due to bowflare slamming and regular waves may be determined
by the following equation:
Mwbi = k[αiL2ArdkFn1/3/(ω1Cb2d)]
where
Mwbi = maximum bending moment due to bowflare slamming and regular waves
ending moment at station i, where station 10 denotes the midship and station
20 is the AP, not to be less than |Mwi|
|Mwi| = absolute value of wave induced bending moment at station i, as specified in
5C-5-3/5.1.1 for sagging condition, where station 10 denotes the midship and
station 20 is the AP
k = 10.3 (1.05, 3.44) for kN-m (tf-m, Ltf-ft)
αi = envelope curve factors: 0.6, 1.2, 1.8, 2.05, 2.1 and 2.0, corresponding to
stations at 0.1, 0.2, 0.3, 0.35, 0.4, and 0.5L from the FP, respectively. Linear
interpolation may be used for intermediate values
ω1 = natural frequency of the 2-node hull girder vibration of the vessel in the wet
mode, in rad/second. If not known, the following equation may be used
= μ [B D3/(Δs Cb L3)]1/2 + 1.4 ≥ 3.7
where
μ = 23400 (7475, 4094)
Δs = Δ{1.2 + B/(3d)}
Δ = displacement as defined in 5C-5-3/5.5.1(b) in kN (tf, Ltf)
d = draft as defined in 3-1-1/9 in m (ft)
Ar = the maximum value of Ari in the forebody region
Ari = bowflare shape parameter at station i forward of the quarter length, up to the
FP of the vessel, to be determined between the LWL and the highest deck, as
follows:

∑ [b ]
2 1/ 2
= (bTi/Hi) j + s 2j , j = 1, n n≥4

5
dk = 0.2 ∑b
i
Ti

= nominal half deck width based on forward five stations of the FP, 0.05L,
0.1L, 0.15L and 0.2L, (see 5C-5-3/Figure 21)
where
bTi = Σb j at station i

Hi = Σsj at station i
bj = local change (increase) in beam for the j-th segment at station i
(see 5C-5-3/Figure 20)
sj = local change (increase) in freeboard up to the highest deck for the j-th
segment at station i forward (see 5C-5-3/Figure 20)
The still water shear force used to calculate the total shear force can be determined from the maximum
negative shear force or minimum positive shear force whichever is applicable in the container
cargo loading conditions.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 639
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 3 Load Criteria 5C-5-3

The shear force due to bowflare slamming and regular waves may be determined by the following
equation:

Fwbi = Ksi[c2 L Ar dk Fn1 / 3 /(ω1 Cb2 d)]

where
Fwbi = maximum positive wave induced shear force due to bowflare slamming and
regular waves at station i, where station 10 denotes the midship, kN (tf, Ltf),
not to be less than Fwi
Fwi = positive wave induced shear force (see 5C-5-3/5.1.2 ) at station i, where
station 10 denotes the midship, kN (tf, Ltf)
c2 = 66.95 (6.825, 22.386) for kN (tf, Ltf)
Ksi = shear envelope curve factor at station i
= 0.0 for the forward perpendicular
= 1.0 for 0.7L to 0.85L from the aft end of L
= 0.5 for 0.5L to 0.6L from the aft end of L
Linear interpolation may be used for intermediate values.
Fn = 0.514 Vd /(gL)1/2, for SI and MKS units
1/2
= 1.688 Vd /(gL) , for US units
Vd is the design speed, as defined in 3-2-14/3, in knots. g is the acceleration due to gravity (9.807
m/sec2, 32.2 ft/sec2). Fn is not to be taken less than 0.225.
L, B, D and Cb are as defined in Section 3-1-1. Cb is not to be taken less than 0.6.

TABLE 3
Values of α
b/do α b/do α
≤ 1.00 0.00 4.00 20.25
1.50 9.00 5.00 22.00
2.00 11.75 6.00 23.75
2.50 14.25 7.00 24.50
3.00 16.50 7.50 24.75
3.50 18.50 ≥ 25.0 24.75

TABLE 4
Values* of Ai and Bi
Ai Bi
- 0.05L 1.25 0.3600
FP 1.00 0.4000
0.05L 0.80 0.4375
0.10L 0.62 0.4838
0.15L 0.47 0.5532
0.20L 0.33 0.6666
0.25L 0.22 0.8182
0.30L 0.22 0.8182
* Linear interpolation may be used for intermediate values

640 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 3 Load Criteria 5C-5-3

FIGURE 18
Distribution of Bottom Slamming Pressure Along the Section Girth

centerline

b* do (1/10 draft)

Ps

FIGURE 19
Ship Stem Angle, γ
F.P.

Stem
Angle

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 641
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 3 Load Criteria 5C-5-3

FIGURE 20
Definition of Bow Flare Geometry for Bow Flare Shape Parameter

highest deck b4

s4

s3
b3

s2
βij
(body plan angle)
b2

s1

b1
LWL
centerline

FIGURE 21
Definition of Half Deck Width

highest deck line

B T5

LWL B T1

CL

0.2L FP

642 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 3 Load Criteria 5C-5-3

13 Other Loads

13.1 Vibrations
In addition to the vibratory hull girder loads induced by bottom and bow slamming specified in 5C-5-3/11,
vibratory responses of hull structures induced by the propulsion system and waves are also to be examined,
as applicable.

13.3 Ice Loads

For vessels intended for special services, such as navigating in cold regions, consideration is to be given to
the effects of ice loads in assessing the strength of the hull structure.
In this case, the limits of the ice loads are to be furnished and analyzed by the designer.

13.5 Accidental Loads

The effects of possible accidental loads on the stiffening systems in the design of the main supporting
members of the side and bottom shell structures are to be considered. The pressures for the flooded
condition, as specified in Note 8 of 5C-5-3/Table 2 for watertight bulkheads, and nominal magnitudes of
the accidental loads with respect to collision or grounding, as outlined in the ABS Guide for Assessing
Hull-Girder Residual Strength, may be applied for this purpose.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 643
PART Section 4: Initial Scantling Criteria

5C
CHAPTER 5 Vessels Intended to Carry Containers (130 meters
(427 feet) to 450 meters (1476 feet) in Length)

SECTION 4 Initial Scantling Criteria

1 General

1.1 Strength Requirements (1998)

This section specifies the minimum strength requirements for the hull structure with respect to the
determination of initial scantlings, including the hull girder, shell and bulkhead plating, frames/stiffeners
and main supporting members. Once the minimum scantlings are determined, the strength of the resulting
design is to be assessed in accordance with Section 5C-5-5. The assessment is to be carried out by means
of an appropriate structural analysis, as per 5C-5-5/9, in order to establish compliance with the failure
criteria in 5C-5-5/3, 5C-5-5/5 and 5C-5-5/7. Structural details are to comply with 5C-5-5/1.7.
The requirements for the hull girder strength are specified in 5C-5-4/3. The requirements in 5C-5-4/7 and
5C-5-4/9 are applicable to container carriers having upper wing torsional boxes and special consideration
is to be given to vessels without upper wing torsional boxes. The required scantlings of double bottom
structures, side structures, deck structures, longitudinal bulkheads and transverse bulkheads structures are
specified in 5C-5-4/11, 5C-5-4/13, 5C-5-4/15, 5C-5-4/17, 5C-5-4/19, 5C-5-4/21, 5C-5-4/23 and 5C-5-4/25,
respectively. 5C-5-4/Figure 1 shows the paragraph numbers giving scantling requirements for the various
structural components of typical container carriers. For hull structures beyond 0.4L amidships, the initial
scantlings are to be determined in accordance with Section 5C-5-6.

1.3 Calculation of Load Effects (1998)

Approximation equations are given in 5C-5-4/11 through 5C-5-4/25 and Section 5C-5-6 for calculating the
maximum bending moments and shear forces for main supporting members clear of the end brackets for
typical structural arrangements and configurations. For designs with different structural configurations,
these local load effects may be determined from a proper 3D structural analysis at the early design stages,
as outlined in 5C-5-5/9, for the combined load cases specified in 5C-5-3/9, excluding the hull girder load
components. In this case, the results of detailed stress analysis are to be submitted for review.

1.5 Structural Details (1 July 2008)

See 5C-5-5/1.7 and 5C-5-4/Figure 2.
Stiffening members, cell guides and doublers for container fittings are not to be directly welded to hatch
corners. During construction, hatch corners are not to be altered to create space to accommodate cell guides.
Where container fittings are fitted for container securing, doubler pads are to be welded at least 100 mm
(4 in.) away from curved edges of hatch corners.

1.7 Evaluation of Grouped Stiffeners (1 July 2005)

Where several members in a group with some variation in requirement are selected as equal, the section
modulus requirement may be taken as the average of each individual requirement in the group. However,
the section modulus requirement for the group is not to be taken less than 90% of the largest section
modulus required for individual stiffeners within the group. Sequentially positioned stiffeners of equal
scantlings may be considered a group.

644 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

FIGURE 1
Scantling Requirement Reference by Subsection
3-2-1/17 5C-5-4/17.7
5C-5-4/17.9 5C-5-4/19
5C-5-4/19
5C-5-4/19

5C-5-4/5.5
5C-5-4/21.1 5C-5-4/17.7.2
5C-5-4/21.5
5C-5-4/17.1 5C-5-4/17.7
5C-5-4/19

5C-5-4/15.5
5C-5-4/17.5
5C-5-4/17.11
5C-5-4/17.13
5C-5-4/23.9

5C-5-4/13.3

5C-5-4/5.3
5C-5-4/13.1
5C-5-4/23.1
5C-5-4/23.5

5C-5-4/21.3
5C-5-4/21.7 5C-5-4/23.3
5C-5-4/23.7
5C-5-4/21.9

5C-5-4/15
5C-5-4/25.1

5C-5-4/15.11 5C-5-4/25.3
5C-5-4/21.1
5C-5-4/21.5

5C-5-4/11.7
5C-5-4/11.25
5C-5-4/11.5 5C-5-4/11.19

5C-5-4/11.21 5C-5-4/11.3.2
5C-5-4/11.23
5C-5-4/11.3.1

5C-5-4/11.13 5C-5-4/11.11
C . L. 5C-5-4/11.15
5C-5-4/11.17
5C-5-4/11.15
5C-5-4/11.17

FIGURE 2
Improvement of Hatch Corners and Heavy Insert Deck Plate

(t)

Thick Insert Plate

(ti )

Generous
Corner Radius
Cell Guide

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 645
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

3 Hull Girder Strength

3.1 Hull Girder Section Modulus (1998)

3.1.1 Hull Girder Section Modulus Amidships (2010)
The required hull girder section modulus amidships is to be calculated in accordance with 3-2-1/3.7,
3-2-1/5, and 3-2-1/9 where the calculation of the total vertical bending moment, Mt, is in accordance
with 5C-5-3/7.1.1. For the assessment of the ultimate strength as specified in Section 5C-5-5 and
the determination of initial net structural scantlings, the net hull girder section modulus amidships,
SMn, is to be calculated in accordance with 5C-5-4/3.1.2 below. The Q factor for H40 strength
steel with thickness greater than 51 mm or H47 strength steel is to be specially considered in
accordance with the requirements in the ABS Guide for Application of Higher-Strength Hull
Structural Thick Steel Plates in Container Carriers.
3.1.2 Effective Longitudinal Members
The hull girder section modulus calculation is to be carried out in accordance with 3-2-1/9 as modified
below. To suit the strength criteria based on a “net” ship concept, the nominal design corrosion
values specified in 5C-5-2/Table 1 are to be deducted in calculating the net section modulus, SMn.

3.1.3 Extent of Midship Scantlings

The items included in the hull girder section modulus amidships are to be extended as necessary to
meet the hull girder section modulus required at the location being considered. The required hull
girder section modulus can be obtained as Mt/fp at the location being considered, except if (Mt)max /fp
is less than SMmin in 3-2-1/3.7.1(b). In this case, the required section modulus is to be obtained by
multiplying SMmin by the ratio of Mti/(Mt)max where Mti is the total bending moment at the location
under consideration and (Mt)max is the maximum total bending moment amidships.

3.3 Hull Girder Moment of Inertia (1998)

The hull girder moment of inertia is to be not less than required by 3-2-1/3.7.2.

3.5 Transverse Strength (1998)

To ensure adequate transverse strength of the hull girder, the requirements for the sizes and scantlings of
the primary transverse supporting members, such as the cross deck box beams on top of watertight and
mid-hold strength transverse bulkheads, specified in this section, as well as the requirements for the
arrangement of transverse bulkheads given in other sections of the Rules are to be satisfied

5 Hull Girder Shearing Strength (1998)

5.1 General
The net thicknesses of the side shell and longitudinal bulkhead plating are to be determined based on the
total vertical shear force, Ft, and the permissible shear stress fs, given below.
Ft = FS + ku kc FW kN (tf, Ltf)
fs = 11.96/Q kN/cm2 (1.220/Q tf/cm2, 7.741/Q Ltf/in2) at Sea
= 10.87/Q kN/cm2 (1.114/Q tf/cm2, 7.065/Q Ltf/in2) in Port
where
FS = still-water shear force based on the envelope curve required by 5C-5-3/3.1 for all
anticipated loading conditions at the location considered, in kN (tf, Ltf).
FW = vertical wave shear force, as given in 5C-5-3/5.1.2, with kw = 1.0, in kN (tf, Ltf).
FW for in-port condition may be taken as zero.
For vessels having significant bow flare, the value of FW at the forebody is subject to
special consideration, as specified in 5C-5-3/11.3.3.

646 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

Q = material conversion factor

= 1.0 for ordinary strength steel
= 0.78 for Grade H32 steel
= 0.72 for Grade H36 steel
= 0.68 for Grade H40 steel
ku, kc may be taken as unity unless otherwise specified.
The shear stresses in the side shell and longitudinal bulkhead plating (net thickness) may be calculated
using a direct analysis to determine the general shear distribution. When a direct calculation is not available
and the longitudinal bulkhead is located at any point not less than 0.045B but no further than 0.12B from
the side shell, the net thickness of the side shell and longitudinal bulkhead plating may be obtained from
the equations given in 5C-5-4/5.3 and 5C-5-4/5.5 below.
The nominal design corrosion values, as given in 5C-5-2/Table 1, for the side shell and longitudinal bulkhead
plating are to be added to the “net” thickness.

5.3 Net Thickness of Side Shell Plating

ts ≥ Ft Ds m/I fs cm (in.)
where
Ft and fs are as defined above.
Ds = shear distribution factor for side shell
= 0.515 (As/A)(-0.143 + 2.109 As/A)(1.021 − 0.363 b/B) for Type A
= 0.515 (As/A)(-0.266 + 2.449 As/A)(1.029 − 0.692 b/B) for Type B
= 0.515 (As/A)(-0.032 + 1.934 As/A)(0.981 − 0.538 b/B) for Type C
Ab = total projected area of the net longitudinal bulkhead plating above inner bottom (one
side), in cm2 (in2)
As = total projected area of the net side shell plating (one side), in cm2 (in2)
A = Ab + As
b = distance between outer longitudinal bulkhead and side shell, in m (ft)
B = breadth of the vessel, in m (ft), as defined in 3-1-1/5
Sections of Types A, B and C are defined in 5C-5-3/Figure 17.
I = moment of inertia of the “net” hull girder section at the position considered in, cm4 (in4)
m = first moment of the “net” hull girder section, in cm3 (in3), about the neutral axis, of
the area between the vertical level at which the shear stress is being determined and
the vertical extremity of the section under consideration.

5.5 Net Thickness of the Longitudinal Bulkhead Plating

tb ≥ Ft Db m/I fs cm (in.)
where
Db = shear distribution factor for longitudinal bulkhead plating
= 0.550 (Ab/A)(-0.120 + 2.445 Ab/A)(0.975 + 0.431 b/B) for Type A
= 0.550 (Ab/A)(-0.198 + 2.480 Ab/A)(0.969 + 0.741 b/B) for Type B
= 0.550 (Ab/A)(0.098 + 1.934 Ab/A)(1.022 + 0.612 b/B) for Type C
All other parameters are as defined in 5C-5-4/5.3 above.

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Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

7 Hull Girder Torsional Stiffness (1998)

The strength criteria are based on the following assumptions and limitations to prevent excessive hull
girder distortion in operation.
i) b0 ≤ 0.905 B

ii) L0 ≤ 0.75 L

iii) αM ΓM ≥ 32 Cn (TM + TS) L20 (2ωM + he b0)l0/[E ( l 20 + b02 )]

where
b0 = width of the hatch opening amidships, measured between the inboard edges of the
strength deck, in m (ft)
L, B, D = length, breadth, depth of the vessel, in m (ft), as defined in Section 3-1-1
Cn = 1.0 for vessel without deck girders or with a centerline deck girder inboard of
lines of hatch openings
= 0.95 for vessel with two continuous longitudinal deck girders inboard of lines of
hatch openings
TM = nominal wave-induced torsional moment amidships, in kN-m (tf-m, Ltf-ft), as
defined in 5C-5-3/5.1.5
TS = still-water torsional moment amidships, in kN-m (tf-m, Ltf-ft), as defined in
5C-5-3/3.1
L0 = effective length, in m (ft), of the consecutive hatch openings between engine room
and forepeak space, as defined in 5C-5-4/9.3
l0 = length of the hatch opening amidships, in m (ft)
E = modulus of elasticity of the material, may be taken as 2.06 × 108 kN/m2
(2.1 × 107 tf/m2, 1.92 × 106 Ltf/ft2) for steel.
he = D−e

αM = 1 + 0.04 L20 JM /ΓM

ΓM = warping constant of the net hull girder section amidships, in m6 (ft6), (see Appendix
5C-5-A3)
JM = St. Venant torsional constant of the net hull girder section amidships, in m4 (ft4), (see
Appendix 5C-5-A3)
ωM = warping function (see Appendix 5C-5-A3)of the net hull girder section amidships at
the inboard edge of the strength deck plating, clear of hatch corner, in m2 (ft2)
e is as defined in 5C-5-3/5.1.5, measured from the baseline of the vessel, positive upward.
For designs which do not satisfy these assumptions, an appropriate hull girder analysis to verify the offered
torsional stiffness is to be submitted for review.

648 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

9 Torsion-induced Longitudinal Stress (1998)

9.1 Total Torsion-induced Longitudinal Stress, (Warping Stress)

The total warping stress in deck structures may be obtained from the following equation:
fLW = fLWW + fLWS N/cm2 (kgf/cm2, lbf/in2)
where
fLWW = wave-induced warping stress in N/cm2 (kgf/cm2, lbf/in2), as specified in 5C-5-4/9.3

fLWS = still-water warping stress in N/cm2 (kgf/cm2, lbf/in2), as specified in 5C-5-4/9.5

The total warping stress is not to be greater than the permissible warping stress, fw, as specified in 5C-5-4/9.7.

9.3 Wave-induced Warping Stress

When a direct calculation using finite element analysis is not available, the wave-induced warping stress
may be determined as specified below:
9.3.1 For Cargo Space Forward of Engine Room
9.3.1(a) The Maximum Wave Induced Warping Stress in the Strength Deck Plating in way of Hatch
Opening. The maximum wave-induced warping stress, fLWW, in the strength deck plating in way
of hatch opening may be obtained from the following equation:
fLWW = k CwTM L0 b0ωM /(BαM ΓM) N/cm2 (kgf/cm2, lbf/in2)
where
k = 0.0123 (0.0123, 0.583)
Cw = Cn (1 + η Cl)
Cn is as defined in 5C-5-4/7.

Cl is a parameter, as given in 5C-5-4/Figure 5, for the specified stations in function of η, ΓE/R, ΓFC,
lE/R , lFC , ICB , I, b0 and l0, as defined below.
TM = nominal wave-induced torsional moment amidships, in kN-m (tf-m, Ltf-ft),
as defined in 5C-5-3/5.1.5
L0 = effective length, in m (ft), of the consecutive hatch openings at the strength
deck level between the aft end of the hatch opening immediately forward of
the engine room and the forward end of the foremost hatch opening
= l1 + δl2
l1 = length measured between the aft end of the hatch opening immediately
forward of the engine room and the forward end of the first hatch opening
that has the same width as that amidships, in m (ft), as shown in
5C-5-4/Figure 3
l2 = length of the fore-end hatch opening area, in m (ft), as shown in
5C-5-4/Figure 3
δ = (b0′/B′)f /(b0/B)M ≤ 1.0
(b0′/B′)f = average ratio of the hatch opening width to the mean vessel’s breadth for all
hatch openings in the fore-end hatch opening region, l2
(b0/B)M = ratio of the hatch opening width to the vessel’s breadth amidships
b0, b0′ = width, in m (ft), of the strength deck hatch opening amidships and the mean
width of the fore-end hatch opening region, l2, respectively, measured
between the inboard edges of the strength deck, as shown in 5C-5-4/Figure 3

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Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

B , B′ = vessel’s breadth, in m (ft), amidships and the mean vessel’s breadth of the
fore-end hatch opening region, l2, respectively, as shown in 5C-5-4/Figure 3
η = [(αM ΓM)/(α Γ)] (ω /ωM)

α = 1 + 0.04 L20 J/Γ

Γ = warping constant of the net hull girder section under consideration, in m6
(ft6), (see Appendix 5C-5-A3)
J = St. Venant torsional constant of the net hull girder section under consideration,
in m4 (ft4), (see Appendix 5C-5-A3)
ω = warping function, (see Appendix 5C-5-A3), of the net hull girder section
under consideration at the inboard edge of the strength deck plating, clear of
hatch corner, in m2 (ft2)
αM, JM, ΓM and ωM are as defined in 5C-5-4/7.
ΓE/R, ΓFC = warping constant, in m6 (ft6), determined in way of the closed hull girder
section immediately abaft of the forward bulkhead of the engine room, and
in way of the closed hull girder section immediately forward of the foremost
hatch opening, respectively
lE/R, lFC = length, in m (ft), of the closed hull girder section in the engine room and in
the fore-end region, respectively
ICB , I = net moment of inertia, in m4 (ft4), about the vertical axis z of the cross deck
box beam at the vessel’s centerline and of the side longitudinal deck box,
respectively, under consideration (5C-5-4/Figure 4)
l0 = as defined in 5C-5-4/7
The following items may be included in the calculation of the moment of inertia ICB of the cross
deck box beam:
• Transverse hatch end coaming plate and continuous stiffeners (above the strength deck)
• Cross deck plating and continuous beams at the strength deck level
• Bottom and top plating and continuous stiffeners of the cross deck box beam
• Side transverse plates and continuous stiffeners of cross deck box beam
The following items may be included in the calculation of the moment of inertia I of the side
longitudinal deck box:
• Strength deck plating and continuous longitudinals
• Side shell and longitudinal bulkhead plating and continuous longitudinals. Effective depth of
side shell and longitudinal bulkhead is equal to the distance between the strength deck and the
second deck, but not to be more than 0.22D
• Second deck plating and continuous longitudinals, if the distance between strength and second
decks does not exceed 0.22D
• Continuous longitudinal hatch side coaming (plate and continuous longitudinal stiffeners)
9.3.1(b) The Maximum Wave Induced Warping Stress at the Top of a Continuous Longitudinal Hatch
Coaming. The maximum wave-induced warping stress, fLWW, for the top of the continuous longitudinal
hatch coaming may be obtained from the equation given in 5C-5-4/9.1 above by substituting the
warping function ω by ωc as defined below, and using Cl as given in 5C-5-4/Figure 5 for the hatch
coaming top.
ωc = ω + 0.5 h b0

650 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

where
h = height, in m (ft), of the continuous longitudinal hatch coaming of the hull
girder section under consideration
b0 = width, in m (ft), of the hatch opening of the hull girder section under
consideration
9.3.2 For Cargo Space Abaft Engine Room
The maximum wave-induced warping stress, fLWW, in the strength deck plating in way of hatch
opening may be obtained from the following equation:
fLWW = k Cw′ TM′ L0′ b0′ ω′/(B′ α′ Γ′) N/cm2 (kgf/cm2, lbf/in2)
where
k = 0.0123 (0.0123, 0.583)
Cw′ = Cn (1 + η′ Cl)

η′ = [(α′ Γ′)/(α Γ)] (ω/ω′)

ω, α and Γ are as defined in 5C-5-4/9.3.1 above and are to be determined at the hull girder section
under consideration.
ω′, α′ and Γ′ are as defined in 5C-5-4/9.3.1 above for ω, α and Γ and are to be determined at the
hull girder section immediately abaft the engine room (station B in 5C-5-4/Figure 5).
ΓE/R′ = warping constant in way of the closed hull girder section immediately
forward of the aft bulkhead of the engine room
TM′ = nominal wave-induced torsional moment, in kN-m (tf-m, Ltf-ft), in way of the
hull girder section immediately abaft the engine room, as defined in 5C-5-3/5.1.5
L0′ = length, in m (ft), of the consecutive hatch openings at the strength deck level
abaft the engine room
b0′, B′ = width, in m (ft), of hatch opening immediately abaft the engine room and the
vessel’s breadth, respectively, at the mid-length of that hatch opening, in m (ft)
Cn is as defined in 5C-5-4/7.
Cl is a parameter as given in 5C-5-4/Figure 5.

9.3.3 For Hatch Openings in Forecastle Deck

For vessels with hatch openings in the forecastle deck, the maximum wave-induced warping
stress, fLWW, in the forecastle deck plating in way of hatch opening may be obtained from the
equation specified in 5C-5-4/9.3.1 above with the appropriate coefficients given in 5C-5-4/Figure 5.

9.5 Still-water Warping Stress

The still-water warping stresses at the inboard edge of strength deck plating and at the top of continuous
longitudinal hatch coaming may be obtained from the equations in 5C-5-4/9.3 using TS in lieu of TM, or TS′
in lieu of TM′, where TS is as specified in 5C-5-3/3.1 and TS′ is still-water torsional moment, in kN-m (tf-m,
Ltf-ft), at the section corresponding to TM′.
TM′ is as specified in 5C-5-4/9.3.2.

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Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

9.7 Permissible Warping Stress

9.7.1
Permissible warping stress may be obtained from the following equation:
fw = C Sm fy − (fV + fH + f2) N/cm2 (kgf/cm2, lbf/in2)
where
C = 0.90 for the inboard edge of the strength deck
= 0.95 for the top of the continuous longitudinal hatch side coaming
Sm = strength reduction factor, as defined in 5C-5-4/11.3.1
fy = minimum specified yield point of the material of the member for which the
warping stress is calculated, in N/cm2 (kgf/cm2, lbf/in2)
fV = stress due to vertical still-water and wave-induced hull girder bending
moments, as specified in 5C-5-4/9.7.2 below, in N/cm2 (kgf/cm2, lbf/in2)
fH = stress due to horizontal wave-induced bending moment, as specified in
5C-5-4/9.7.3 below, in N/cm2 (kgf/cm2, lbf/in2)
f2 = secondary stress, in N/cm2 (kgf/cm2, lbf/in2)
= f P + fB
fP = stress due to external water pressure on side shell, in N/cm2 (kgf/cm2,
lbf/in2), as specified in 5C-5-4/17.5.2
fP may be taken as zero when a vessel is under hogging condition.
fB = stress due to dynamic container load on transverse bulkhead, in N/cm2
(kgf/cm2, lbf/in2), as specified in 5C-5-4/17.5.3
fB may be taken as zero at Stations A, B, C, G, F′ and G′ shown in 5C-5-4/Figure 5.

9.7.2
Stress due to vertical hull girder bending moment may be obtained from the following equation:
fV = k MV /SMV N/cm2 (kgf/cm2, lbf/in2)
where
k = 1000 (1000, 2240)
MV = vertical hull girder bending moment at the section under consideration, in
kN-m (tf-m, Ltf-ft)
= MS + 0.40 fMV MW
MS = still-water bending moment at the section under consideration, in kN-m
(tf-m, Ltf-ft), as specified in 5C-5-3/3.1
MW = vertical wave-induced bending moment amidships, in kN-m (tf-m, Ltf-ft), as
specified in 5C-5-3/5.1.1
fMV = distribution factor, as shown in 5C-5-3/Figure 2
SMV = vertical hull girder net section modulus at the strength deck or at the top of
continuous longitudinal hatch coaming at the section under consideration, in
m-cm2 (ft-in2), determined based on 5C-5-4/3.1.2

652 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

9.7.3
Stress due to horizontal hull girder bending moment may be obtained from the following equation:
fH = k Mh/SMH N/cm2 (kgf/cm2, lbf/in2)
where
k = 1000 (1000, 2240)
Mh = horizontal wave-induced bending moment, in kN-m (tf-m, Ltf-ft), at the
section under consideration
= 0.7 mh MH
MH = horizontal wave-induced bending moment amidships, in kN-m (tf-m, Ltf-ft),
as specified in 5C-5-3/5.1.3
mh = distribution factor, as specified in 5C-5-3/5.1.3

SMH = 2 Iz/b0 = horizontal hull girder net section modulus, in m-cm2 (ft-in2)
Iz = hull girder net moment of inertia of the section under consideration about the
vertical axis through the centerline of the vessel, in cm2-m2 (in2-ft2)
b0 = width of the hatch opening measured between the inboard edges of the
strength deck at the section under consideration, in m (ft)

FIGURE 3
Strength Deck Definition of l1, l2, b0, b0′, B and B′
l1 l2

0.5B'a
0.5B
Engine 0.5B'b
room
Hatch
0.5b0 Hatch opening Hatch
0.5b'0a 0.5b'0b
openings "a" opening
amidship "b"
L
C

Foremost
hatch opening

l2a l2b

L0 = l1 + δl2

δ = (b0′/B′)f /(b0/B)M ≤ 1.0

(b0′/B′)f = (b0a′/Ba′) (l2a/l2) + (b0b′/Bb′) (l2b/l2)

(b0/B)M = b 0 /B

Note: b0, b0a′, b0b′, Ba′, and Bb′ are to be measured at midpoint
of the hatch opening under consideration

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 653
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

FIGURE 4
Deck Structure

B l

B C
W1 W2

0.5b0

A A C
Z
C.L.

l0

STRENGTH DECK

0.22D

Z - AXIS Z - AXIS Z - AXIS

SECTION A - A SECTION B - B SECTION C - C

654 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

FIGURE 5
Specified Stations and Coefficients for Warping Stress Calculation

Vessels with hatch

opening in forecastle deck

F' G'

Forecastle

Station E : the forward end of the hatch that has the

same width of b0 as that amidships
Station F : the forward ends of hatches where there is
a change of b0, other than station E or G C.L.
Station G : the forward end of the foremost hatch l2 lFC

w' = distance between the hatch corners of two adjacent

hatch opening as shown below
w = width of cross deck

A B C D D' E F G

w
l0(D&D') l0 (E) '
l0 (F) w
Engine
'
(D&D')

Room

b0/2 (E)
b0/2

b0/2
w

(F)
w
C.L.
W.T. mid-Hold
Strength
Bhd Bhd
l0' l E/R l1 l2 lFC
Vessels without hatch opening in forecastle deck
or
Vessels without forecastle

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 655
 FIGURE 5 (continued)

656
Part

Specified Stations and Coefficients for Warping Stress Calculations Section

Chapter

Hatch Opening on strength Deck Level Hatch Opening on Forecastle

Deck
Station A B C D D′ E F G F′ G′
Coefficients &
α3 Cl α3 Cl α1 Cl α4 Cl α4 Cl α5 Cl α5 Cl α2 Cl α2 Cl α2 Cl
Parameters
0.05 0.45 0.25 1.75 20 1.90 0.010 0.900 0.010 0.750 0.020 0.52 0.100 0.50 2.5 0.45 7.00 0.97 2.00 1.06
0.2 0.55 1.00 2.25 40 2.00 0.024 0.950 0.024 0.870 0.060 0.53 0.300 0.51 10.0 0.55 9.00 0.98 2.20 1.08
5C Specific Vessel Types

0.40 0.63 2.00 2.60 60 2.05 0.030 0.975 0.030 0.910 0.120 0.56 0.500 0.53 20.0 0.62 11.00 1.04 2.40 1.27
4 Initial Scantling Criteria

Strength Deck 0.70 0.72 3.00 2.80 80 2.08 0.036 1.000 0.036 0.930 0.300 0.68 0.700 0.56 30.0 0.65 13.00 1.10 2.60 1.44
1.00 0.77 4.00 2.95 100 2.10 0.042 1.025 0.042 0.950 0.480 0.86 0.900 0.57 40.0 0.66 15.00 1.16 2.70 1.53
1.30 0.79 5.00 2.98 120 2.12 0.048 1.035 0.048 0.960 0.720 1.09 1.200 0.58 60.0 0.67 17.00 1.22 2.80 1.62
2.40 0.80 12.00 3.00 200 2.15 0.100 1.050 0.100 0.970 0.960 1.20 1.600 0.59 95.0 0.68 19.00 1.22 3.00 1.62
0.05 0.25 5 0.010 0.60 0.010 0.48 0.020 0.40 0.025 0.15 2.5
0.024 0.62 0.024 0.58 0.060 0.41 0.050 0.16
1.75* 1.4* 0.030 0.64 0.030 0.60 0.120 0.42 0.100 0.18
Coaming Top .05** (0.7**) (0.7**) 0.036 0.67 0.036 0.62 0.300 0.47 0.300 0.21 0.1**
0.042 0.69 0.042 0.63 0.480 0.56 0.500 0.22
0.048 0.70 0.048 0.64 0.720 0.62 0.700 0.23
3.00 20.00 250 0.100 0.72 0.100 0.65 0.960 0.64 1.600 0.24 100.0
α 1 = (Γ ⋅ L0 ) / (Γ E / R ⋅ l E / R ) α 2 = (Γ ⋅ L0 ) / (Γ FC ⋅ l FC ) α 3 = (Γ ⋅ L0′ ) / (Γ E′ / R ⋅ l E / R )
α 4 = [(I CB / b0 ) / (I / l 0 )] / η α5 = (w′/w)2 α4

Notes:
1 Defintition of parameters and coefficients are specified in 5C-5-4/9.3, except otherwise noted.
For calculation of α4, b0 and l0 are as shown in the figure.
5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)

b0 is to be measured at the midpoint of the hatch opening.

2 For different value of parameter, Cl may be linearly interpolated or extrapolated.
3 Cl may be taken as zero where blank.
4 * -- Fully connected to the deck house; ** -- End bracket only.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012

5C-5-4
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

11 Double Bottom Structures

11.1 General (1998)

11.1.1 General
The arrangement of bottom girders, solid floors, stiffening systems and access openings, and the
depth of the double bottom are to be in compliance with the Rules. Centerline and side girders are
to be fitted, as necessary, to provide sufficient stiffness and strength for docking loads as well as
those specified in Section 5C-5-3.
11.1.2 Framing
Generally, bottom and inner bottom plating is to be longitudinally framed, except for limited areas
such as those in way of pipe tunnels and the bilge areas.
11.1.3 Keel Plate Thickness
The thickness of the flat keel plate is to be not less than that required for the bottom shell plating
at that location by 5C-5-4/11.3.1, increased by 1.5 mm (0.06 in.), except where the submitted
docking plan specifies all docking blocks be arranged away from the keel.
11.1.4 Definition of Bottom Shell Plating
The term “bottom shell plating” refers to the plating from the keel to the upper turn of the bilge
amidships, but the upper turn of the bilge is not to be taken more than 0.2D above the baseline.
11.1.5 Non-prismatic Double Bottom Structures
See Note in 5C-5-4/Figure 8 for non-prismatic double bottom structures where the breadths of the
forward and aft ends are different.

11.3 Bottom Shell and Inner Bottom Plating (1998)

The net thicknesses of the bottom shell and inner bottom plating, over the midship 0.4L, are to satisfy the
hull girder section modulus requirements in 5C-5-4/3.1, the buckling and ultimate strength requirements in
5C-5-5/5, and are to be not less than that obtained from the following.
11.3.1 Bottom Shell Plating (1 July 2005)
The net thickness of the bottom shell plating, tn, is to be not less than t1, t2 and t3, specified as follows:
t1 = 0.73s(k1 p/f1)1/2 mm (in.)
t2 = 0.73s(k2 p/f2)1/2 mm (in.)
1/2
t3 = c s(Sm fy/E) mm (in.)
where
s = spacing of bottom longitudinals, in mm (in.)
k1 = 0.342
k2 = 0.500
p = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), as specified in 5C-5-3/Table 2.
For pipe tunnel, pressure is to be taken as that of the adjacent tank.
f1 = permissible bending stress, in longitudinal direction, in N/cm2 (kgf/cm2, lbf/in2)
= (0.95 − 0.67α1SMRB/SMB)Sm fy ≤ Kp Sm fy
Kp = 0.40 for load case 1-“a” in 5C-5-3/Table 2
= 0.36 for L > 210 m (689 ft) for load case 1-“b” in 5C-5-3/Table 2
= 0.36 + (210 − L)/900 for L ≤ 210 m [0.36 +( 689 – L)/2950 for L ≤ 689 ft] for
load case 1-“b” in 5C-5-3/Table 2

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

SMRB = reference net hull girder section modulus based on material factor of the
bottom flange of the hull girder, in cm2-m (in2-ft)
= 0.9 SM
SM = required gross hull girder section modulus amidships, in accordance with
5C-5-4/3.1.1, with kw defined in 5C-5-3/5.1.1 for the purpose of calculating
Mw (sagging and hogging), based on material factor of the bottom flange of
the hull girder, in cm2-m (in2-ft)
SMB = design (actual) net hull girder section modulus at the bottom, amidships in
cm2-m (in2-ft)
α1 = Sm1 fy1/Sm fy
Sm = strength reduction factor for plating under consideration
= 1.0 for ordinary mild steel
= 0.95 for Grade H32 steel
= 0.908 for Grade H36 steel
= 0.875 for Grade H40 steel
Sm1 = strength reduction factor for the bottom flange of the hull girder
fy = minimum specified yield point of the material, in N/cm2 (kgf/cm2, lbf/in2)
fy1 = minimum specified yield point of the bottom flange of the hull girder, in
N/cm2 (kgf/cm2, lbf/in2)
f2 = permissible bending stress, in the transverse direction, in N/cm2 (kgf/cm2,
lbf/in2)
= 0.80 Sm fy
E = modulus of elasticity of the material, may be taken as 2.06 × 107 N/cm2
(2.1 × 106 kgf/cm2, 30 × 106 lbf/in2) for steel
c = 0.7N2 − 0.2, not to be taken less than 0.4Q1/2
N = Rb (Q/Qb)1/2
Rb = (SMRBH /SMB)1/2
SMRBH = reference net hull girder section modulus for hogging bending moment based
on the material factor of the bottom flange of the hull girder, in cm2-m (in2-ft)
= 0.9SMH
SMH = required gross hull girder section modulus amidships in accordance with
5C-5-4/3.1.1 for hogging total bending moment, with kw defined in
5C-5-3/5.1.1 for the purpose of calculating Mw (hogging), based on the
material factor of the bottom flange of the hull girder, in cm2-m (in2-ft)
Q, Qb = material conversion factor in 5C-5-4/5 for the bottom plating and the bottom
flange of the hull girder, respectively
Bottom shell plating may be transversely framed in pipe tunnels or bilge areas, provided the net
thickness of the bottom shell plating, tn, is not less than t4 specified below:
t4 = 0.73 s k (k2 p/f1)1/2 mm (in.)

658 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

where
s = spacing of bottom transverse frame, in mm (in.)
k = (3.075(α)1/2 − 2.077)/(α + 0.272), (1 ≤ α ≤ 2)
= 1.0 (α > 2)
α = aspect ratio of the panel (longer edge/shorter edge)
k2 = 0.500
All other parameters are as defined above.
The net thickness, t3, may be determined based on Sm and fy of the hull girder strength material
required at the location under consideration.
In addition to the foregoing, the net thickness of the bottom shell plating, outboard of 0.3B from
the centerline of the vessel, is to be not less than that of the lowest side shell plating required by
5C-5-4/13.1, adjusted for the spacing of the bottom/bilge longitudinals or frames and the material
factors. For a curved plate where girth spacing is greater than that of the adjacent bottom plating,
the spacing may be modified by the equations, as specified in 5C-5-4/11.7.
11.3.2 Inner Bottom Plating (1999)
The net thickness of the inner bottom plating, tn, is to be not less than t1, t2 and t3, specified as
follows:
t1 = 0.73s(k1 p/f1)1/2 mm (in.)
t2 = 0.73s(k2 p/f2)1/2 mm (in.)
t3 = c s (Sm fy /E)1/2 mm (in.)
where
s = spacing of inner bottom longitudinals, in mm (in.)
k1 = 0.342
k2 = 0.500

p = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), as specified in 5C-5-3/Table 2.

For pipe tunnel, internal pressure is to be taken as that of the adjacent tank.
f1 = permissible bending stress, in longitudinal direction, in N/cm2 (kgf/cm2, lbf/in2)
= (0.95 − 0.50α1SMRB /SMB) Sm fy ≤ 0.55Sm fy , where SMB /SMRB is not to be
taken more than 1.4
f2 = permissible bending stress, in the transverse direction, in N/cm2 (kgf/cm2,
lbf/in2)
= 0.85 Sm fy

α1 = Sm1 fy1/Sm fy
Sm = strength reduction factor, as defined in 5C-5-4/11.3.1, for the inner bottom
plating
Sm1 = strength reduction factor, as defined in 5C-5-4/11.3.1, for the bottom flange
of the hull girder
fy = minimum specified yield point of the inner bottom plating, in N/cm2
(kgf/cm2, lbf/in2)
fy1 = minimum specified yield point of the bottom flange of the hull girder, in
N/cm2 (kgf/cm2, lbf/ in2)

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 659
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

c = 0.7N2 − 0.2, not to be taken less than 0.4Q1/2

N = Rb[(Q/Qb) (y/yn)]1/2
Q, Qb = material conversion factor in 5C-5-4/5 for the inner bottom plating and the
bottom flange of the hull girder, respectively
y = vertical distance, in m (ft), measured from the inner bottom to the neutral
axis of the hull girder section
yn = vertical distance, in m (ft), measured from the bottom to the neutral axis of
the section
SMRB, SMB and E are as defined in 5C-5-4/11.3.1.
Inner bottom plating may be transversely framed in pipe tunnels, provided the net thickness of the
inner bottom plating, tn, is not less than t4, as specified below:
t4 = 0.73 s k(k2 p/f1)1/2 mm (in.)
where
s = spacing of inner bottom transverse frames, in mm (in.)
k2 = 0.500

k = (3.075(α)1/2 − 2.077)/(α + 0.272) (1 ≤ α ≤ 2)

= 1.0 (α > 2)
α = aspect ratio of the panel (longer edge/shorter edge)
All other parameters are as defined above.
The net thickness, t3, may be determined based on Sm and fy of the hull girder strength material
required at the location under consideration.

11.5 Bottom and Inner Bottom Longitudinals (2007)

The net section modulus of each bottom or inner bottom longitudinal or each transverse frame in pipe
tunnels, in association with the effective plating to which it is attached, is to be not less than that obtained
from the following equations:
SM = M/fb cm3 (in3)

M = cpsl2 103/k N-cm (kgf-cm, lbf-in.)

where
c = 1.0 without struts
= 0.65 with effective struts
p = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), as specified in 5C-5-3/Table 2 for bottom
and inner bottom plating, respectively. For pipe tunnel, pressure is to be taken as that
of the adjacent tank.
s = spacing of longitudinals or transverse frames, in mm (in.)
l = span of longitudinals or transverse frames between effective supports, as shown in
5C-5-4/Figure 6, in m (ft)
k = 12 (12, 83.33)
fb = permissible bending stresses, in N/cm2 (kgf/cm2, lbf/in2)
= 1.2[1.0 − 0.65α1SMRB /SMB]Sm fy ≤ 0.60Sm fy for bottom longitudinals
= 1.1[1.0 − 0.50α1SMRB /SMB]Sm fy ≤ 0.65Sm fy for inner bottom longitudinals
= 0.70 Sm fy for transverse frames

660 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

α1 = Sm1 fy1/Sm fy
Sm = strength reduction factor, as defined in 5C-5-4/11.3.1, for the material of
longitudinals or transverse frames considered
Sm1 = strength reduction factor, as defined in 5C-5-4/11.3.1, for the bottom flange material
of the hull girder
fy = minimum specified yield point for the material of longitudinals or transverse frames
considered, in N/cm2 (kgf/cm2, lbf/in2)
fy1 = minimum specified yield point of the bottom flange of the hull girder, in N/cm2
(kgf/cm2, lbf/in2)
SMRB and SMB are as defined in 5C-5-4/11.3.1.
The net section modulus of the bottom longitudinals, outboard of 0.3B from the centerline of the vessel, is
also to be not less than that of the lowest side longitudinal required by 5C-5-4/13.3, adjusted for the span
and spacing of the longitudinals and the material factors.
Where effective struts are fitted between bottom and inner bottom longitudinals, the net section modulus of
the inner bottom longitudinals is also to be not less than 90% of that required for the bottom longitudinals.
When determining compliance with the foregoing, an effective breadth, be, of the attached plating is to be
used in the calculation of the section modulus of the design longitudinal. be is to be calculated from section
a) of 5C-5-4/Figure 7.

11.7 Bilge Plate and Longitudinals/Frames (1 July 2005)

In general, the bilge plate is to be longitudinally stiffened. The net thickness of the bilge plate is to be not
less than required in 5C-5-4/11.3.1, adjusted for the spacing of the bilge longitudinals or frames and the
material factors. Where girth spacing of bilge longitudinals is greater than that of the adjacent bottom
plating, the spacing may be modified by the following equation in calculations of t1 and t2:
s = kr1 sg mm (in.)
but not to be taken less than the spacing of the longitudinals of the adjacent bottom plating
where
sg = girth spacing of bilge longitudinals, in mm (in.)

kr1 = (1 − 0.5 sg /R)2 but not less than 0.55

R = radius of bilge, in mm (in.)
Longitudinals around the bilge are to be graduated in size from that required for the lowest side longitudinal
to that required for the most outboard bottom longitudinals. The permissible bending stresses are to be
calculated at the lowest side longitudinal and the most outboard bottom longitudinal.
For container carriers with length over 250 m in length, bilge longitudinals of asymmetric cross section below
1/ d from the waterline are to have double-sided support connections to side transverses. Alternatively, the
3
fatigue strength of the welded connections of the slot connections is to be evaluated using a fine mesh
finite element model.
α = kr2 sg /s but not less than 1.0
where
s = spacing of bilge transverse frames, in mm (in.)
sg = longer edge (girth) of the panel under consideration, in mm (in.)
kr2 = 15/(1 + 40 sg /R)
R = radius of bilge, in mm (in.)

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 661
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

In no case is the net thickness of the bilge plate to be less than that of the adjacent bottom plating.
The net thickness of the web part of the transverse frame or of the web plate is to be not less than t1, as
required in 5C-5-4/11.21, for the bottom floor.
In addition, the net section modulus of the frame is to be not less than that required in 5C-5-4/11.5 for
transverse frames nor less than that required for side frames with a nominal pressure at the upper turn of
the bilge in 5C-5-4/13.3, adjusted for the span and spacing of the frames and the material factors.

11.9 Bottom Struts (1998)

Where struts are fitted as an effective supporting system for bottom and inner bottom longitudinals, they
are to be positioned so as to divide the span into approximately equal intervals. They are to have net area
not less than Ar1 or Ar2, whichever is greater, obtained from the following equations:
Ar1 = k pa b s/wa cm2 (in2)
Ar2 = k pb b s/wb cm2 (in2)
where
k = 0.01 (0.01, 1.0)
b = mean length of longitudinals supported, in mm (in.)
s = spacing of longitudinals, in mm (in.)
pa = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), at the strut considered as specified in
Case “a” of 5C-5-3/Table 2 for inner bottom longitudinals
pb = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), at the strut considered as specified in
Case “b” of 5C-5-3/Table 2 for bottom longitudinals
wa = 0.45 Sm fy

wb = 0.45fy[1 − 0.0254(fy /E)(l/r)2]

l = unsupported span of the strut, in cm (in.)

r = least radius of gyration of the strut, in cm (in.)
fy = minimum specified yield point of the struts, in N/cm2 (kgf/cm2, lbf/in2)
E is as defined in 5C-5-4/11.3.1.

11.11 Centerline Girder in way of Cargo Holds (2004)

The net thickness of the centerline girder in cargo holds is to be not less than t1 and t2, as defined below,
whichever is greater:
t1 = (0.045L + 4.5)R mm for SI or MKS Units
= (0.00054L + 0.177)R in. for U.S. Units
t2 = 10F1/(db fs) mm for SI or MKS Units
= F1/(db fs) in. for U.S. Units
where F1 is the maximum shear force of the centerline girder, as obtained from the equations given below
(see also 5C-5-4/1.3 ). Alternatively, F1 may be determined from finite element analyses, as specified in
5C-5-5/9 with the combined load cases in 5C-5-3/9. However, in no case is F1 to be taken less than 85%
of that determined from the equations below.
F1 = k 750 α1 γ1 n1 n2 p ls s1 N (kgf, lbf) for λ ≤ 1.5

F1 = k 259 γ1 n1 n2 p bs s1 N (kgf, lbf) for λ > 1.5

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

where
k = 1.0 (1.0, 2.24)
α1 = 0.505 − 0.183λ
λ = ls /bs
ls = unsupported length of the double bottom structures under consideration, in m (ft), as
shown in 5C-5-4/Figure 8
bs = unsupported width of the double bottom structures under consideration, in m (ft), as
shown in 5C-5-4/Figure 8
γ1 = |2.67x/(ls − sf) − 0.33| ≤ 1.0
n1 = 0.0374(s1/sf)2 − 0.326 (s1/sf) + 1.289
n2 = 1.3 − (sf /12) for SI or MKS Units
= 1.3 − (sf /39.37) for U.S. Units
s1 = sum of one-half of girder spacings on both sides of the centerline girder, in m (ft)
sf = average spacing of floors, in m (ft)
x = longitudinal distance from the mid-span of length ls to the location on the girder
under consideration, in m (ft)
p = nominal pressure, in kN/m2 (tf/m2, Ltf/ft2), as specified in 5C-5-3/Table 2
db = depth of the double bottom structure, in cm (in.)
fs = permissible shear stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.50 Sm fy
R = 1.0 for ordinary mild steel
= fym /Sm fyh for higher strength material
fym = specified minimum yield point for mild steel, in N/cm2 (kgf/cm2, lbf/in2)
fyh = specified minimum yield point for higher tensile steel, in N/cm2 (kgf/cm2, lbf/in2)
L = length of vessel, in m (ft), as defined in 3-1-1/3.1
Sm and fy are as defined in 5C-5-4/11.3.1
Pipe tunnels may be substituted for centerline girders, provided the tunnel is suitably stiffened by fitting
deep, closely spaced transverse webs. The thickness of each girder forming the pipe tunnel and center
girder within the pipe tunnel, if any, is not to be less than that required for the bottom side girder (see
5C-5-4/11.13).

11.13 Bottom Side Girders

The net thickness of the bottom side girders is to be not less than t1 and t2, as defined below.
t1 = (0.026L + 4.5)R mm for SI or MKS Units
= (0.00031L + 0.177)R in. for U.S. Units
t2 = 10F2/(db fs) mm for SI or MKS Units
= F2/(db fs) in. for U.S. Units
where F2 is the maximum shear force of the side girder under consideration, as obtained from the equations
given below (see also 5C-5-4/1.3). Alternatively, F2 may be determined from finite element analyses, as
specified in 5C-5-5/9 with the combined load cases in 5C-5-3/9; however, in no case is F2 to be taken less
than 85% of that determined from the equations below.

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Section 4 Initial Scantling Criteria 5C-5-4

F2 = k 750 α2 β1 γ1 n3 n4 p ls s2 N (kgf, lbf) for λ ≤ 1.5

F2 = k 214 β1 γ1 n3 n4 p bs s2 N (kgf, lbf) for λ > 1.5

where
k = 1.0 (1.0, 2.24)
α2 = 0.445 − 0.17λ
β1 = 1.25 − (2z1/bs) ≥ 0.6
n3 = 1.072 − 0.0715(s2/sf)
n4 = 1.2 − (sf /18) for SI or MKS Units
= 1.2 − (sf /59.1) for U.S. Units
s2 = sum of one-half of girder spacings on both sides of side girder, in m (ft)
z1 = transverse distance from the centerline of the vessel to the location of the girder under
consideration, in m (ft).
γ1, ls, bs, sf, λ, p, db, fs, L and R are as defined in 5C-5-4/11.11.

11.15 Longitudinally Stiffened Bottom Girders (1999)

In addition to 5C-5-4/11.11 or 5C-5-4/11.13, the net thickness of longitudinally stiffened bottom girders is
to be not less than t3, as defined below:
t3 = c s (Sm fy /E)1/2 mm (in.)
where
s = space of stiffeners, in mm (in.)
c = 0.7N2 − 0.2, not to be taken less than 0.4Q1/2
N = Rb[(Q/Qb) (y/yn)]1/2
Q, Qb = material conversion factor in 5C-5-4/5 for the bottom girder plating and the bottom
flange of the hull girder, respectively
y = vertical distance, in m (ft), measured from the lower edge of the bottom girder plating
to the neutral axis of the hull girder section.
yn = vertical distance, in m (ft), measured from the bottom to the neutral axis of the
section
Sm, fy, SMRB, SMB, Rb and E are defined in 5C-5-4/11.3.1.
The net thickness, t3, may be determined based on Sm and fy of the hull girder strength material required at
the location under consideration.

11.17 Bottom Tank Boundary Girders (2007)

The net thickness of the double bottom girders forming boundaries of deep tanks, in addition to complying with
5C-5-4/11.11, 5C-5-4/11.13 and 5C-5-4/11.15, is to be not less than obtained from the following equations:
t1 = 0.73s(k1 p/f1)1/2 mm (in.)
t2 = 0.73s(k2 p/f2)1/2 mm (in.)
where
s = spacing of longitudinals or vertical stiffeners, in mm (in.)
k1 = 0.342 for longitudinally stiffened plating
2
= 0.500k for vertically stiffened plating
k2 = 0.50

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

k = (3.075 α1/2 − 2.077)/(α + 0.272) (1 ≤ α ≤ 2)

= 1.0 (α > 2)
α = aspect ratio of the panel (longer edge/shorter edge)
p = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), at the lower edge of each plate, as
specified in 5C-5-3/Table 2
f1 = permissible bending stress in longitudinal direction, in N/cm2 (kgf/cm2, lbf/in2)
= 1.25[1 − 0.33(z1/B) − 0.52 α1 (SMRB/SMB) (y/yn)] Sm fy ≤ 0.75Sm fy
f2 = permissible bending stress in vertical direction, in N/cm2 (kgf/cm2, lbf/in2)
= 0.95 Sm fy
y = vertical distance, in m (ft), measured from the neutral axis of the hull girder transverse
section to the lower edge of each plate where the plating is longitudinally stiffened
= vertical distance, in m (ft), measured from the neutral axis of the hull girder transverse
section to the mid-depth of the double bottom height where the plating is vertically
stiffened
B = vessel’s breadth, in m (ft), as defined in 3-1-1/5
SMRB and SMB are as defined in 5C-5-4/11.3.1.
Sm, fy and α1 are as defined in 5C-5-4/11.5.
z1 and yn are as defined in 5C-5-4/11.13 and 5C-5-4/11.15, respectively.

11.19 Vertical Web on Bottom Tank Boundary Girder

Vertical webs on double bottom watertight girders, if fitted, are to have scantlings not less than obtained
from the following equations.
SM = M/fb cm3 (in3)
M = p sl2 105/k1 N-cm (kgf-cm, lbf-in)
As = F/fs cm2 (in2)
F = k2 500 psl N (kgf, lbf)
where
k1 = 12 (12, 44.64)
k2 = 1.0 (1.0, 2.24)
p = nominal pressure at the midspan of the vertical web, in kN/m2 (tf/m2, Ltf/ft2), as
specified in 5C-5-3/Table 2.
s = spacing of the vertical web, in m (ft)
l = span of the vertical web, in m (ft)
l may be modified in accordance with 5C-5-4/Figure 9
fb = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.7 Sm fy
fs = permissible shear stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.4 Sm fy
Sm = strength reduction factor for the vertical web, as defined in 5C-5-4/11.3.1
fy = minimum specified yield point for the vertical web, in N/cm2 (kgf/cm2, lbf/in2)
The net thickness of the web plate of the vertical web is to be not less than t1, obtained in 5C-5-4/11.15, as
adjusted for the material of the web plate.

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

11.21 Bottom Floors (1 July 2005)

The net thickness of the floors is to be not less than t1 and t2, as defined below, whichever is greater:
t1 = (0.025L + 4.0)R mm for SI or MKS Units
= (0.0003L + 0.157)R in. for U.S. Units
t2 = 10F3 /(db fs) mm for SI or MKS Units
= F3 /(db fs) in. for U.S. Units
where
L = length of the vessel, in m (ft), as defined in Section 3-1-1, but need not exceed 240 m
(787 feet)
F3 = maximum shear force at the floor under consideration, as obtained from the equation
given below (see also 5C-5-4/1.3). Alternatively, F3 may be determined from finite
element analyses, as specified in 5C-5-5/9 with the combined load cases in 5C-5-3/9.
However, in no case is F3 to be taken less than 85% of that determined from the
equation below:
= k 650 α3 β2 γ2 p bs s3 N (kgf, lbf)
k = 1.0 (1.0, 2.24)
α3 = 0.5 η (0.66 − 0.08η)
β2 = 2z2/bs ≥ 0.4

γ2 = (ls − 2x)/(3 sf) ≤ 1.0

η = (ls /bs)(sg /sf)1/4

sg = average spacing of girders, in m (ft)
s3 = sum of one-half of floor spacings on both sides of floor, in m (ft)
x = longitudinal distance from the mid-span of lengths ls to the location of the floor under
consideration, in m (ft)
z2 = transverse distance from the centerline of the vessel to the location on the floor under
consideration, in m (ft)
ls, bs, sf, p, db, fs, and R are as defined in 5C-5-4/11.11.

11.23 Tank End Floors (1998)

The net thickness of the tank end floors is to be not less than required in 5C-5-4/23.1.

11.25 Transverses in Pipe Tunnel

Transverses in pipe tunnels are to have scantlings, SM and As, not less than obtained from the following
equations:
SM = M/fb cm3 (in3)

M = psl2 105/k1 N-cm (kgf-cm, lbf-in)

As = F/fs cm2 (in2)

F = k2 600psl N (kgf, lbf)

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

where
k1 = 10 (10, 37.2)
k2 = 1.0 (1.0, 2.24)

p = nominal pressure for the bottom transverse, in kN/m2 (tf/m2, Ltf/ft2), as specified in
5C-5-3/Table 2. p for the inner bottom transverse is to be taken 90% of that for the
bottom transverse.
s = spacing of the transverse, in m (ft)
l = span of the transverse, in m (ft)
l may be modified in accordance with 5C-5-4/Figure 9
fb = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.7 Sm fy
fs = permissible shear stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.4 Sm fy
Sm = strength reduction factor for the transverses, as defined in 5C-5-4/11.3.1
fy = minimum specified yield point for the transverses, in N/cm2 (kgf/cm2, lbf/in2)
The net thickness of the web plate of the transverse is to be not less than t1, obtained in 5C-5-4/11.21
above, adjusted for the material of the web plate.

11.27 Container Supporting Structures (1998)

Generally, bottom floors and girders are to be so arranged to support container loads. Where the container
pads are not in line with these members, brackets or headers are to be provided to transmit the container
loads to these members. Each bracket or header is to have a net section modulus, SM, in cm3 (in3), and a
net sectional area, As, in cm2 (in2), of the web portion not less than that obtained from the following equations:
SM = M/fb
As = F/fs
where
M = maximum bending moment due to container loads, in N-cm (kgf-cm, lbf-in)
fb = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.80 Sm fy
F = shearing force at the location under consideration due to container loads, in N (kgf, lbf)
fs = permissible shear stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.53 Sm fy
Sm and fy are as defined in 5C-5-4/11.3.1.
The container loads are to be obtained from the equations in 5C-5-3/5.5.2(b) in association with the maximum
design container weight for load case 3 specified in Item C in 5C-5-3/Table 1.

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

FIGURE 6
Unsupported Span of Longitudinals

Trans Trans
a) Supported by transverses

F.B. F.B.

Trans Trans
b) Supported by transverses
and flat bar stiffeners

F.B. F.B.

d/2

Trans Trans

c) Supported by transverses,
flat bar stiffeners
and brackets

668 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

FIGURE 7
Effective Breadth of Plating be

Longitudinal

Mx
M

c l c lo
For bending For bending
at ends at midspan s = spacing of longitudinals

a) For bending at midspan

clo/s 1.5 2 2.5 3 3.5 4 4.5 and greater

be/s 0.58 0.73 0.83 0.90 0.95 0.98 1.0

b) For bending at ends [be/s = (0.124cl/s – 0.062)1/2]

cl/s 1 1.5 2 2.5 3 3.5 4.0

be/s 0.25 0.35 0.43 0.5 0.55 0.6 0.67

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Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

FIGURE 8
Definitions of ls, bs, h, db, dw, ds and y

W.T.Bhd W.T.Bhd

cargo hold

lS

Longitudinal Elevation

Strength deck

2nd deck
dS

h dw

y bS/2
db

bs / 2
dw
h h h
dw
bs / 2
bs / 2

Note
Where the breadths of the forward and aft ends of double bottom structure are different, i.e., non-prismatic double bottom
structure, bs is to be taken as the actual breadth of double bottom structure depending upon the longitudinal distance (x) from
the mid-span of length ls under consideration. For calculation of shear force for side girders, the actual length of side girders
is to be used in lieu of ls. All other formulae and parameters are applicable to shear force calculations. (See 5C-5-4/11.11,
5C-5-4/11.13 and 5C-5-4/11.21.)

670 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

FIGURE 9
Effectiveness of Brackets for Main Supporting Members

Span Span

d/2
d/4

ha ha
d
d Length of Length of
Bracket Bracket

Where face plate area on the member is Where face plate area on the member is not carried along the face
carried along the face of the bracket of the bracket,and where the face plate area on the bracket is at
least one-half the face plate area on the member.

Brackets are not to be considered effective beyond the point where the arm
on the girder or web is 1.5 times the arm on the bulkhead or base.

13 Side Shell Plating and Longitudinals (1998)

13.1 Side Shell Plating (1 July 2007)

The net thickness of the side shell plating, in addition to compliance with 5C-5-4/5.3, is to be not less than
t1, t2 and t3 specified below for the midship 0.4L:
t1 = 0.73s(k1 p/f1)1/2 mm (in.)
t2 = 0.73s(k2 p/f2)1/2 mm (in.)
t3 = c s (Sm fy /E)1/2 mm (in.)
where
s = spacing of side longitudinals, in mm (in.)
k1 = 0.342
k2 = 0.500

p = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), at the lower edge of each plate strake,
as specified in 5C-5-3/Table 2, but is not to be taken less than 85% of the pressure at
the upper turn of the bilge. The nominal pressure at the upper turn of bilge for case
“a” in 5C-5-3/Table 2 is not to be taken less than that at bottom boundary of wing
tank where the bottom boundary is located between the upper turn of bilge and 0.35D
above the base line.

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

f1 = permissible bending stress, in longitudinal direction, in N/cm2 (kgf/cm2, lbf/in2)

= [0.835 − 0.40 α1 (SMRB /SMB)(y/yb)]Sm fy, below neutral axis, where SMB/SMRB is not
to be taken more than 1.4
= [0.835 – 0.52α2 (SMRD/SMD)(y/yn)] Sm fy, above neutral axis
f1 is not to be taken greater than:

0.43Smfy for L ≥ 210 m (689 ft)

[0.43 + (210 – L)/2600]Sm fy for L < 210 m
[0.43 + (689 – L)/8531]Sm fy for L < 689 ft
f2 = permissible bending stress, in the vertical direction, in N/cm2 (kgf/cm2, lbf/in2)
= 0.80 Sm fy
α1 = Sm1 fy1/Sm fy
α2 = Sm2 fy2/Sm fy
Sm = strength reduction factor, as defined in 5C-5-4/11.3.1, of the side shell plating
Sm1 = strength reduction factor, as defined in 5C-5-4/11.3.1, of the bottom flange of the hull
girder
Sm2 = strength reduction factor, as defined in 5C-5-4/11.3.1, of the strength deck flange of
the hull girder
fy = minimum specified yield point of the side shell plating, in N/cm2 (kgf/cm2, lbf/in2)
fy1 = minimum specified yield point of the bottom flange of the hull girder, in N/cm2
(kgf/cm2, lbf/in2)
fy2 = minimum specified yield point of the strength deck flange of the hull girder, in N/cm2
(kgf/cm2, lbf/in2)
SMRD = reference net hull-girder section modulus based on the material factor of the strength
deck flange of the hull girder, in cm2-m (in2-ft).
= 0.95 SM
SM = required gross hull girder section modulus amdiships, in accordance with 5C-5-4/3.1.1,
with kw defined in 5C-5-3/5.1.1 for the purpose of calculating Mw (sagging and hogging),
based on the material factor of the strength deck flange of the hull girder, in cm2-m
(in2-ft)
SMD = design (actual) net hull girder section modulus at the strength deck amidships, in cm2-m
(in2-ft)
c = 0.7N2 − 0.2, not to be taken less than 0.4Q1/2
N = Rd (Q/Qd)1/2 for the sheer strake
= Rd [(Q/Qd) (ya/yn)]1/2 for other locations above neutral axis
1/2
= Rb [(Q/Qb) (ya/yn)] for locations below neutral axis
Rd = (SMRDS /SMD)1/2
Rb = (SMRBH /SMB)1/2
SMRDS = reference net hull girder section modulus for sagging bending moment based on the
material factor of the strength deck flange of the hull girder, in cm2-m (in2-ft)
= 0.95 SMs

672 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

SMs = required gross hull girder section modulus amidships, in accordance with 5C-5-4/3.1.1,
with kw defined in 5C-5-3/5.1.1 for the purpose of calculating Mw (sagging), based on
material factor of the strength deck flange of the hull girder, in cm2-m (in2-ft)
SMRBH = reference net hull girder section modulus for hogging bending moment based on the
material factor of the bottom flange of the hull girder, in cm2-m (in2-ft)
= 0.9 SMH
SMH = required gross hull girder section modulus amidships, in accordance with 5C-5-4/3.1.1,
with kw defined in 5C-5-3/5.1.1 for the purpose of calculating Mw (hogging), based on
the material factor of the bottom flange of the hull girder, in cm2-m (in2-ft)
Q, Qb, Qd = material conversion factor in 5C-5-4/5 for the side shell plating, the bottom flange
and the strength deck flange of the hull girder, respectively
y = vertical distance, in m (ft), measured from the neutral axis of the hull girder transverse
section to the lower edge of the side shell strake
ya = vertical distance, in m (ft), measured from the neutral axis of the hull girder transverse
section to the lower edge (upper edge) of the side shell strake, when the strake under
consideration is below (above) the neutral axis.
yb = vertical distance, in m (ft), measured from the upper turn of bilge to the neutral axis
of the section
yn = vertical distance, in m (ft), measured from the bottom (deck) to the neutral axis of the
hull girder transverse section, when the strake under consideration is below (above)
the neutral axis
SMRB, SMB, and E are as defined in 5C-5-4/11.3.1.
t1 and t2, as calculated for each plate, need not to be taken in excess of those calculated at the upper turn of
the bilge, respectively, as adjusted for the spacing of the longitudinals and the material factors.
In addition, the net thickness of the side shell plating is not to be taken less than t4, obtained from the
following equation:
t4 = 90(s/1000 + 0.7) [Bd/(Sm fy)2]1/4 + tk mm
t4 = 7.3(s/39.4 + 0.7) [Bd/(Sm fy)2]1/4 + tk in.
where
s = spacing of side frames, in mm (in.)
B = breadth of vessel, as defined in 3-1-1/5, in m (ft)
d = molded draft, as defined in 3-1-1/9, in m (ft)
tk = 0.5 mm (0.02 in.) for mild steel
= 1.0 mm (0.04 in.) for Grade H32 steel
= 1.5 mm (0.06 in.) for Grade H36 steel
All other parameters are as defined above.
The net thickness, t4, is to be applied to the following extent of the side shell plating:
Longitudinal extent: between a section aft of amidships where the breadth at the waterline exceeds 0.9B,
and a section forward of amidships where the breadth at the waterline exceeds 0.6B,
Vertical extent: between 300 mm (12 in.) below the lowest ballast waterline to 0.25d or 2.2 m
(7.2 ft), whichever is greater, above the summer load line.
The net thickness, t3, may be determined based on Sm and fy of the hull girder strength material required at
the location under consideration.

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

In general, the side shell is to be longitudinally framed within the regions of 0.15D from the baseline and
0.15D from the upper deck. Other parts of side shell plating may be transversely framed, provided the net
thickness of the side shell plating is not less than t5, as specified below, and is also not less than that of
adjacent longitudinally framed shell:
t5 = 0.73s k (k2 p/f )1/2 mm (in.)
where
s = spacing of side frames, in mm (in.)
k2 = 0.500
k = (3.075(α)1/2 − 2.077)/(α + 0.272), (1 ≤ α ≤ 2)
= 1.0 (α > 2)
α = aspect ratio of the panel (longer edge/shorter edge)
p = nominal pressure at side shell under consideration, in N/cm2 (kgf/cm2, lbf/in2), as
specified in 5C-5-3/Table 2 for side structural members
f = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= [0.835 − 0.40α1 (SMRB /SMB)(y/yb)]Sm fy ≤ 0.55Sm fy, below neutral axis, where
SMB/SMRB is not to be taken more than 1.4
= 0.55 Sm fy, above neutral axis
All other parameters are as defined above.
For a curved plate where girth spacing is greater than that of the adjacent side plating, the spacing may be
modified by the equations as specified in 5C-5-4/11.7.
The minimum width of the sheer strake for the midship 0.4L is to be obtained from the following equations:
b = 5L + 800 mm for L ≤ 200 m
= 0.06L + 31.5 in. for L ≤ 656 ft
b = 1800 mm for 200 < L ≤ 350 m
= 70.87 in. for 656 < L ≤ 1148 ft
L = length of vessel, as defined in 3-1-1/3.1, in m (ft)
b = width of sheer strake, in mm (in.)
The thickness of the sheer strake is to be increased 25% in way of breaks of superstructures, but this
increase need not exceed 6.5 mm (0.25 in.).

13.3 Side Longitudinals and Side Frames (1 July 2005)

The net section modulus of each side longitudinal or side frame, in association with the effective plating, is
to be not less than that obtained from the following equations:
SM = M/fb cm3 (in3)

M = cpsl2103/k N-cm (kgf-cm, lbf-in)

where
c = 1.0 without struts
= 0.65 with effective struts
p = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), at the side longitudinal considered, as
specified in 5C-5-3/Table 2, but is not to be taken less than 2.25 N/cm2 (0.23 kgf/cm2,
3.27 lbf/in2). For side frames, pressure is to be taken at the middle of the span of the
side frame.

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

s = spacing of side longitudinals or side frames, in mm (in.)

l = span of longitudinals or frames between effective supports, as shown in 5C-5-4/Figure 6,
in m (ft)
k = 12 (12, 83.33)
fb = permissible bending stresses, in N/cm2 (kgf/cm2, lbf/in2)

= 1.5 [0.835 − 0.52α2 (SMRDS /SMD)(y/yn)]Sm fy ≤ 0.85Sm fy

for side longitudinals above neutral axis in load case 3-B in 5C-5-3/Table 2
= 1.0 [0.835 − 0.52α1 (SMRB /SMB)(y/yn)]Sm fy ≤ 0.75Sm fy
for side longitudinals below neutral axis
= 1.5 [0.835 − 0.52α2 (SMRD /SMD)(y/yn)]Sm fy ≤ 0.85Sm fy
for side longitudinals above neutral axis in load case 3-A in 5C-5-3/Table 2
= 0.90 Sm fy for side frames

α2 = Sm2 fy2/Sm fy
Sm, fy and α1 are as defined in 5C-5-4/11.3.1.
Sm2 = strength reduction factor for the strength deck flange of the hull girder, as defined in
5C-5-4/11.3.1
fy2 = minimum specified yield point of the strength deck flange of the hull girder, in N/cm2
(kgf/cm2, lbf/in2)
SMD and SMRDS are as defined in 5C-5-4/13.1 and SMRDS is to be taken not less than 0.5 SMRD.
SMRB and SMB are as defined in 5C-5-4/11.3.1.
SMRD = reference net hull girder section modulus based on material factor of the strength
deck flange of the hull girder, in cm2-m (in2-ft)
= 0.95 SM
SM = reference gross hull girder section modulus amidships in accordance with 5C-5-4/3.1.1,
with kw defined in 5C-5-3/5.1.1 for the purpose of calculating Mw (sagging and
hogging), based on material factor of the strength deck flange of the hull girder, in
cm2-m (in2-ft)
y = vertical distance, in m (ft), measured from the neutral axis of the section to the side
longitudinal under consideration at its connection to the associated plate
yn = vertical distance, in m (ft), measured from the strength deck (bottom) to the neutral
axis of the section, when the longitudinal under consideration is above (below) the
neutral axis
The effective breadth of plating, be, is as defined in 5C-5-4/11.5.
The net moment of inertia of side longitudinals within the region of 0.1D from the strength deck, in association
with the effective plating (bWL tn), is to be not less than that obtained from the following equation:
io = k Ael2fy /E cm4 (in4)
where
k = 610 (610, 8.79)
Ae = net sectional area of the longitudinal with the associated effective plating (bWL tn), in
cm2 (in2)

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

bWL = ce s

ce = 2.25/β − 1.25/β 2 for β ≥ 1.25

= 1.0 for β ≤ 1.25

β = (fy /E)1/2 s/tn
tn = net thickness of the plate, in mm (in.)
D = depth of vessel, in m (ft), as defined in 3-1-1/7
l, s and fy are as defined in 5C-5-4/11.5.
E is as defined in 5C-5-4/11.3.1.
For container carriers with length over 250 m in length, side shell longitudinals of asymmetric cross section
below 1/3d from the waterline are to have lugged slot connections to side transverses. Alternatively, the
fatigue strength of the welded connections of the slot connections is to be evaluated using a fine mesh
finite element model.

13.5 Side Struts (1998)

Where struts are fitted as an effective supporting system for side tank structures, they are to be positioned
so as to divide the span into approximately equal intervals. They are to have net area not less than Ar1 or
Ar2, whichever is greater, obtained from the following equations:
Ar1 = kpabs/wa cm2 (in2)
Ar2 = kpbbs/wb cm2 (in2)
where
k = 0.01 (0.01, 1.0)
b = mean span of the side frames or side longitudinals supported, in mm (in.)
s = spacing of the side frames or side longitudinals, in mm (in.)
pa = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), at the strut considered, as specified in
Case “a” of 5C-5-3/Table 2 for side longitudinals
pb = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), at the strut considered, as specified in
Case “b” of 5C-5-3/Table 2 for side longitudinals
wa = 0.45 Sm fy
wb = 0.56fy [1 − 0.0254 (fy /E) (l/r)2] when (l/r)2 (fy /E) < 20
= 5.55E (l/r)2 when (l/r)2 (fy /E) ≥ 20
l = unsupported span of the strut, in cm (in.)
r = least radius of gyration of the strut, in cm (in.)
fy = minimum specified yield point of the struts, in N/cm2 (kgf/cm2, lbf/in2)
E is as defined in 5C-5-4/11.3.1.

15 Side Transverses and Side Stringers (1998)

The minimum scantlings for the side transverses and side stringers are to be determined from 5C-5-4/15.1,
5C-5-4/15.3, 5C-5-4/15.5, 5C-5-4/15.7, 5C-5-4/15.9 and 5C-5-4/15.11, as follows. Alternatively, t2 in
5C-5-4/15.1 and 5C-5-4/15.7 and the scantlings in 5C-5-4/15.3 and 5C-5-4/15.5 may be determined from finite
element analyses, as specified in 5C-5-5/9 with the combined load cases in 5C-5-3/9. However, in no case
are the scantlings to be taken less than 85% of those determined from the corresponding equations below.
For this purpose, an additional load case is also to be investigated modifying load case 6 with a full draft.

676 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

15.1 Side Transverse in Double Side Structures (1 July 2005)

The net thickness of the side transverse in a double side is to be not less than t1 and t2, as defined below,
whichever is greater.
t1 = 8.5 mm where L ≥ 200 m

= 0.02L + 4.5 mm where 200 > L ≥ 130 m for SI or MKS Units

= 0.334 in. where L ≥ 656 ft
= 0.00024L + 0.177 in. where 656 ft > L ≥ 427 ft for US Units
t2 = 10F1/(dw fs) mm for SI or MKS Units
= F1/(dw fs) in. for U.S. Units
where F1 is the maximum shear force of the side transverse under consideration, as obtained from the
equations given below (see also 5C-5-4/1.3):
F1 = k190λβ1γ1phs1 N (kgf, lbf)
where
k = 1.0 (1.0, 2.24)
λ = ls/h, but need not be taken more than 2.5

β1 = 1 − 1.25 y/h ≥ 0.45

ls = length of the cargo hold under consideration, in m (ft)

h = height of the double side structure, in m (ft), as shown in 5C-5-4/Figure 8
γ1 = 1.25 if no stringer is installed
= 1.05 if a stringer or stringers are installed within the upper half of the side height
h, but no stringer is installed within the lower half
= 0.93 if a stringer or stringers are installed up to 0.5h from the lower end of the
side height h
s1 = sum of one-half of transverse spacings on both sides of transverse, in m (ft)
y = vertical distance from the inner bottom or the lowest deck level to the location on the
transverse under consideration, as shown in 5C-5-4/Figure 8, in m (ft)
dw = width of the transverse web plate at elevation y, as shown in 5C-5-4/Figure 8, in cm (in.)
p = nominal pressure on the double side structure at an elevation of 0.2h above the lower
end of h, as specified in 5C-5-3/Table 2, in kN/m2 (tf/m2, Ltf/in2)
fs = permissible shear stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.50 Sm fy
L = length of vessel, in m (ft), as defined in 3-1-1/3.1
Sm and fy are as defined in 5C-5-4/11.3.1.
The net thickness of the transverse in the bilge part is to be not less than t1 as required above and the lower
part is also to be not less than t1 as required in 5C-5-4/11.21 for the bottom floor.
Where the shell is longitudinally framed, web stiffeners are to be fitted for the full depth of the transverses
at every longitudinal. Other stiffening arrangement may be considered based on the structural stability of
the web plates.

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

15.3 Side Transverse in Single Side Shell

Side transverse on single skin side shell is to have scantlings not less than that obtained from the following
equations.
15.3.1 Section Modulus
The net section modulus of the side transverse is not to be less than obtained from the following
equation:
SM = M/fb cm3 (in3)

M = 3350λγpsh2/k N-cm (kgf-cm, lbf-in)

where
k = 1.0 (1.0, 3.72)
h = height of the single skin side structure, in m (ft)
λ = ls/h, but need not be taken more than 2.5
γ = 1.0 if no stringer is installed
= 0.8 if a stringer or stringers are installed within the upper half of the side
height h , but no stringer is installed within the lower half
= 0.65 if a stringer or stringers are installed up to 0.5h from the lower end
of side height h
p = nominal pressure on the single skin side structure at an elevation of 0.2h
above the lower end of h, in kN/m2 (tf/m2, Ltf/ft2), as specified in
5C-5-3/Table 2
s = spacing of the side transverse, in m (ft)
fb = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.75 Sm fy
Sm and fy are as defined in 5C-5-4/11.3.1. ls is defined in 5C-5-4/15.1 above.
15.3.2 Web Thickness (1 July 2005)
The net web thickness of the side transverse is not to be less than that obtained from the following
equations:
t1 = 8.5 mm where L ≥ 200 m

= 0.02L + 4.5 mm where 200 > L ≥ 130 m for SI or MKS Units

= 0.334 in. where L ≥ 656 ft
= 0.00024L + 0.177 in. where 656 ft > L ≥ 427 ft for U.S. Units
t2 = k3F/(dw fs) mm (in.)

F = k160λβ1γ1psh N (kgf, lbf)

where
k3 = 10 (10, 1.0)
fs = permissible shear stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.50 Sm fy
dw = depth of the side transverse, in cm (in.)
β1 = 1 − 1.25y/h ≥ 0.45
λ, p, s and h are as defined in 5C-5-4/15.3.1 above. k, γ1 and y are defined in 5C-5-4/15.1 above.

678 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

15.3.3 Web Stiffeners

Web stiffeners extending to the full depth of the side transverses are to be fitted at every longitudinal.
Other stiffening arrangements may be considered based on the structural stability of the web plates.

15.5 Side Transverse in Underdeck Passageway

Side transverses in the underdeck passageway forming an upper wing torsional box are to have scantlings
not less than obtained from the following equations:
15.5.1 Section Modulus
The net section modulus of the side transverses is not to be less than that obtained from the
following equation:
SM = (M1 + M2)/fb cm3 (in3)

M1 = c1pusl2105/k1 N-cm (kgf-cm, lbf-in)

M2 = k8λγ1phs1y N-cm (kgf-cm, lbf-in)

where
k1 = 12 (12, 44.64)

c1 = 1 − 0.1l/pu
pu = nominal pressure calculated at the mid-span of the side transverse under
consideration, in kN/m2 (tf/m2, Ltf/ft2), as specified in 5C-5-3/Table 2
s = spacing of the side transverses, in m (ft)
l = span of the side transverse, in m (ft), l may be modified in accordance with
5C-5-4/Figure 9
y = k2(l − hu /2) ≥ 0
k2 = 100 (100, 12)
hu = height of the underdeck passageway, in m (ft)
fb = permissible bending stress, in N/cm2 (kgf/cm2, Ibf/in2)
= 0.85 Sm fy

Sm and fy are as defined in 5C-5-4/11.3.1. k, λ, γ1, p, h and s1 are as defined in 5C-5-4/15.1 above.

15.5.2 Depth of Side Transverse

The depth of the side transverse is not to be less than that obtained from the following equation:
d = kl mm (in.)
where
k = 125 (1.5)
l is as defined in 5C-5-4/15.5.1 above.
15.5.3 Web Thickness
The net web thickness of the side transverse is not to be less than that obtained from the following
equation:
t = k3 (F1 + F2)/(dw fs) mm (in.) but not less than 8.0 mm (0.31 in.)

F1 = k500c2pusl N (kgf, lbf)

F2 = k14.25λγ1phs1 N (kgf, lbf)

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

where
k3 = 10 (10, 1.0)

c2 = 1 − 0.2l/pu
fs = permissible shear stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.50 Sm fy
dw = depth of the side transverse, in cm (in.)
pu, s and l are as defined in 5C-5-4/15.5.1 above. k, λ, γ1, p, h and s1 are as defined in 5C-5-4/15.1
above.
15.5.4 Web Stiffeners
Web stiffeners extending to the full depth of the side transverses are to be fitted at least every two
longitudinals. Other stiffening arrangements may be considered based on the structural stability of
the web plates.

15.7 Side Stringers in Double Side Structures (1 July 2005)

If longitudinal stringers are installed in the double side below the 2nd deck, the net thickness of the stringer
plate is to be not less than t1 and t2, as defined below, whichever is greater.

t1 = 9.5 mm where L ≥ 200 m

= 0.02L + 5.5 mm where 200 > L ≥ 130 m for SI or MKS Units

= 0.374 in. where L ≥ 656 ft
= 0.00024L + 0.217 in. where 656 ft > L ≥ 427 ft for U.S. Units
t2 = 10F2/(ds fs) mm for SI or MKS Units
= F2/(ds fs) in. for U.S. Units
where F2 is the maximum shear force in the stringer under consideration, as obtained from the approximation
equations given below (see also 5C-5-4/1.3 ).
F2 = k95 γ2 pslss2 N (kgf, lbf)
where
k = 1.0 (1.0, 2.24)
γ2 = 2x/ls ≥ 0.45
s2 = sum of the one-half of stringer spacings on both sides of each stringer, in m (ft)
x = longitudinal distance from the mid-span of length ls to the location on the stringer
under consideration, m (ft)
ds = width of the stringer, as shown in 5C-5-4/Figure 8, in cm (in.)
ps = nominal pressure on the double side structure at the level of the stringer under
consideration, as specified in 5C-5-3/Table 2, in kN/m2 (tf/m2, Ltf/in2)
L, ls, and fs are as defined in 5C-5-4/15.1.
In addition, the net thickness of the longitudinally framed plate is to be not less than that obtained from the
following equation:
t3 = c s (Sm fs/E)1/2 mm (in.)

680 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

where
s = spacing of longitudinals, in mm (in.)
c = 0.7N2 − 0.2, not to be taken less than 0.2
N = Rd [(Q/Qd) (y/yn)]1/2 for side stringers located above neutral axis
= Rb [(Q/Qb) (y/yn)]1/2 for side stringers located below neutral axis
Rd = (SMRDS /SMD)1/2
Rb = (SMRBH /SMB)1/2
SMRDS = reference net hull girder section modulus for sagging bending moment based on the
material factor of the strength deck flange of the hull girder, in cm2-m (in2-ft)
= 0.95 SMS
SMS = reference gross hull girder section modulus in accordance with 5C-5-4/3.1.1 for
sagging total bending moment, with kw defined in 5C-5-3/5.1.1 for the purpose of
calculating Mw (sagging), based on the material factor of the strength deck flange of
the hull girder, in cm2-m (in2-ft)
SMRBH = reference net hull girder section modulus for hogging bending moment based on the
material factor of the bottom flange of the hull girder, in cm2-m (in2-ft)
= 0.9SMH
SMH = reference gross hull girder section modulus in accordance with 5C-5-4/3.1.1 for
hogging total bending moment, with kw defined in 5C-5-3/5.1.1 for the purpose of
calculating Mw (hogging), based on the material factor of the bottom flange of the
hull girder, in cm2-m (in2-ft)
Q, Qb, Qd = material conversion factor in 5C-5-4/5 for the side stringer plating, the bottom flange
and the strength deck flange of the hull girder, respectively
y = vertical distance, in m (ft), measured from the neutral axis of the hull girder transverse
section to the side stringer.
yn = vertical distance, in m (ft), measured from the neutral axis of the hull girder transverse
section, when the side stringer under consideration is below (above) the neutral axis
Sm and fy are defined in 5C-5-4/11.3.1.
The net thickness, t3, may be determined based on Sm and fy of the hull girder strength material required at
the location under consideration.
Where the shell is transversely framed, web stiffeners are to be fitted for the full width of the side stringer
at every frame. Other stiffening arrangements may be considered based on the structural stability of the
web plates.

15.9 Transverses Forming Tank Boundaries

Where transverses form tank boundaries, the net thickness is also to be not less than as required in 5C-5-4/23.

15.11 Side Stringers Forming Tank Boundaries

15.11.1 Plating
Where the side stringer forms tank boundaries, the net thickness of the boundary plating is also to
be not less than t1 and t2 specified as follows:
t1 = 0.73s(k1 p/f1)1/2 mm (in.)
t2 = 0.73s(k2 p/f2)1/2 mm (in.)

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

where
s = spacing of longitudinals or stiffeners, in mm (in.)
k1 = 0.342, for longitudinally stiffened plating

= 0.500 k2, for transversely stiffened plating

k2 = 0.500

k = (3.075(α)1/2 − 2.077)/(α + 0.272), (1 ≤ α ≤ 2)

= 1.0 (α > 2)
α = aspect ratio of the panel (longer edge/shorter edge)
p = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), as specified in 5C-5-3/Table 2
f1 = permissible bending stress, in longitudinal direction, in N/cm2 (kgf/cm2, lbf/in2)

= c[1.0 − 0.70α1SMRB /SMB (y/yn)] Sm fy ≤ 0.85Sm fy, below neutral axis

= c[1.0 − 0.70α2SMRD /SMD (y/yn)] Sm fy ≤ 0.85Sm fy, above neutral axis
c = 1.1 for longitudinally stiffened plating
= 1.4 for transversely stiffened plating
f2 = permissible bending stress, in the transverse direction, in N/cm2 (kgf/cm2, lbf/in2)
= 0.95 Sm fy

α1 = Sm1 fy1/Sm fy
α2 = Sm2 fy2/Sm fy
Sm = strength reduction factor of the longitudinal bulkhead plating, as defined in
5C-5-4/11.3.1
fy = minimum specified yield point of the longitudinal bulkhead plating, in N/cm2
(kgf/cm2, lbf/in2)
y = vertical distance, in m (ft), measured from the neutral axis of the hull girder
transverse section to the side stringer under consideration
yn = distance, in m (ft), measured from the main deck (bottom) to the neutral axis
of the section
SMRB, SMB, and E are as defined in 5C-5-4/11.3.1.
Sm1 and fy1 are as defined in 5C-5-4/11.5.
Sm2, SMRD and fy2 are as defined in 5C-5-4/13.3.
SMD is as defined in 5C-5-4/13.1.

15.11.2 Stiffeners on Side Stringer

The net section modulus of each longitudinal or stiffener on side stringer forming tank boundaries, in
association with the effective plating, is to be not less than that obtained from the following equations:
SM = M/fb cm3 (in3)

M = cpsl2103/k N-cm (kgf-cm, lbf-in)

682 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

where
k = 12 (12, 83.33)
c = 1.0
p = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), at the longitudinal considered,
as specified in 5C-5-3/Table 2
s = spacing of longitudinals or stiffeners, in mm (in.)
l = span of longitudinals or stiffeners between effective supports, as shown in
5C-5-4/Figure 6, in m (ft)
fb = permissible bending stresses, in N/cm2 (kgf/cm2, lbf/in2)
= 1.1[1.0 − 0.70α1(SMRB /SMB)(y/yn)]Sm fy ≤ 0.80Sm fy
for longitudinals below neutral axis
= 1.6[1.0 − 0.70α2(SMRD /SMD)(y/yn)]Sm fy ≤ 0.80Sm fy
for longitudinals above neutral axis
= 0.90 Sm fy for stiffeners
y = vertical distance, in m (ft), measured from the neutral axis of the hull girder
transverse section to the longitudinal under consideration at its connection to
the associated plate
SMRB and SMB are as defined in 5C-5-4/11.3.1.
Sm1 and fy1 are as defined in 5C-5-4/11.5.
SMRD, Sm2 and fy2 are as defined in 5C-5-4/13.3.

Sm, fy, yn, α1 and α2 are defined in 5C-5-4/15.11.1.

SMD is as defined in 5C-5-4/13.1.

15.13 Container Supporting Structures (1998)

Where brackets or headers are provided to transmit the dynamic container loads due to ship’s motion to the
main supporting side structures, each bracket or header is to have a net section modulus, SM, in cm3 (in3),
and a net sectional area, As, in cm2 (in2), of the web portion not less than that obtained from the following
equations:
SM = M/fb
As = F/fs
where
M = maximum bending moment due to dynamic container load, N-cm (kgf-cm, lbf-in)
fb = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.80 Sm fy
F = shear force at the location under consideration due to dynamic container load, in N
(kgf, lbf)
fs = permissible shear stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.53 Sm fy
Sm and fy are as defined in 5C-5-4/11.5.
The dynamic container loads are to be obtained from the equations in 5C-5-3/5.5.2(b) in association with
the maximum design container weight for load case 5, as specified in Item C in 5C-5-3/Table 1.

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

17 Deck Structures

17.1 Strength Deck Plating (1 July 2005)

In general, the strength deck is to be longitudinally framed. The net thickness of the strength deck plating
is to be not less than that needed to meet the hull girder section modulus requirements in 5C-5-4/3.1 and
the buckling and ultimate strength requirements in 5C-5-5/5, nor is the thickness to be less than t1, t2 and t3,
specified below for the midship 0.4L:
t1 = 0.73s(k1 p/f1)1/2 mm (in.)
t2 = 0.73s(k2 p/f2)1/2 mm (in.)
t3 = cs(Sm fy /E)1/2 mm (in.)
where
s = spacing of deck longitudinals, in mm (in.)
k1 = 0.342
k2 = 0.500

p = nominal deck pressure, in N/cm2 (kgf/cm2, lbf/ in2), as specified in 5C-5-3/Table 2.

f1 = permissible bending stress in longitudinal direction, in N/cm2 (kgf/cm2, lbf/in2)
= 0.15 Sm fy
f2 = permissible bending stress, in the transverse direction, in N/cm2 (kgf/cm2, lbf/in2)
= 0.80 Sm fy
c = 0.5(0.6 + 0.0015L) for SI or MKS units
= 0.5(0.6 + 0.0046L) for US Units
c is to be taken not less than 0.7N2 − 0.2 for vessel less than 267 m (876 ft) in length.
L = length of vessel, in m (ft), as defined in 3-1-1/3.1
N = Rd(Q/Qd)1/2
Rd = (SMRDS /SMD)1/2
SMRDS = reference net hull girder section modulus for sagging bending moment based on the
material factor of the strength deck flange of the hull girder, in cm2-m (in2-ft)
= 0.95SMS
SMS = reference gross hull girder section modulus in accordance with 5C-5-4/3.1.1 for
sagging total bending moment, with kw defined in 5C-5-3/5.1.1 for the purpose of
calculating Mw (sagging), based on the material factor of the strength deck flange of
the hull girder, in cm2-m (in2-ft)
Q, Qd = material conversion factor in 5C-5-4/5 for the deck plating and the strength deck
flange of the hull girder, respectively
Sm, fy and E are as defined in 5C-5-4/11.3.1.
SMD is as defined in 5C-5-4/13.1.
The net thickness, t3, may be determined based on Sm and fy of the hull girder strength material required at
the location under consideration.

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

17.3 Strength Deck Longitudinals (1998)

The net section modulus of each individual deck longitudinal, in association with the effective plating, is to
be not less than that obtained from the following equations:
SM = M/fb cm3 (in3)

M = psl2103/k N-cm (kgf-cm, lbf-in)

where
k = 12 (12, 83.33)
s = spacing of deck longitudinals, in mm (in.)
l = span of longitudinals between effective supports, as shown in 5C-5-4/Figure 6, in m (ft)
p = nominal deck pressure, in N/cm2 (kgf/cm2, lbf/in2), as specified in 5C-5-3/Table 2.
fb = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.3 Sm fy
Sm and fy are as defined in 5C-5-4/11.5.
The effective breadth of plating, be, is as defined in 5C-5-4/11.5.
The net moment of inertia of the deck longitudinal in association with the effective plating (bWL tn) is to be
not less than io, as specified in 5C-5-4/13.3.

17.5 Upper Wing Torsional Box

17.5.1 Width of Torsional Box
In general, the width of the upper wing torsional box is not to be less than 0.009L0, where L0 is as
defined in 5C-5-4/9.3.
17.5.2 Calculation of Secondary Stress due to External Water Pressure on Side Shell
The stress at the strength deck and at the top of a continuous longitudinal hatch side coaming, induced
by external water pressure on the side shell, may be obtained from the following equation:
fP = MP/SM N/cm2 (kgf/cm2, lbf/in2)
where
MP = kQl105 N-cm (kgf-cm, lbf-in)
k = 0.15 (0.15, 0.0403)

Q = k1(0.94C1klh2 + 0.5 h22 + 0.67C1klh1)s kN (tf, Ltf)

k1 = 9.807 (1, 0.028)
kl = 0.5(1 + klo)
s = spacing of side transverses, spacing, in m (ft), below the second deck
l = l0 + 0.5(w1 + w2)
l0 = length of the hatch opening amidships, in m (ft)
w1, w2 = widths of the cross deck box beams, in m (ft), clear of hatch corner, fore and
aft of the hatch opening amidships, as shown in 5C-5-4/Figure 4
SM = net section modulus of the upper wing torsional box, in cm3 (in3), at the inboard
edge of the strength deck or at the top of the continuous longitudinal hatch
side coaming with respect to vertical axis z (5C-5-4/Figure 4) for the hull
girder section under consideration.

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

C1 is as defined in 3-2-1/3.5.
klo is as defined in 5C-5-3/Figure 9.
h1 and h2 are as shown in 5C-5-4/Figure 10 for hull girder section under consideration, in m (ft).
The following items may be included in the calculation of the section modulus SM:
• Strength deck plating and continuous longitudinals
• Side shell and longitudinal bulkhead plating and continuous longitudinals. Effective depth of
side shell and longitudinal bulkhead is equal to the distance between the strength deck and the
second deck
• Second deck plating and continuous longitudinals
• Continuous longitudinal hatch coaming and continuous longitudinal stiffeners
17.5.3 Calculation of Secondary Stress due to Dynamic Container Load on Transverse Bulkhead
The stress at the strength deck and at the top of the continuous longitudinal hatch coaming, induced
by container load on transverse bulkhead and transmitted through cross deck, may be obtained from
the following equation:
fB = MB /SM N/cm2 (kgf/cm2, lbf/in2)
where
MB = kC2R b0105/12 N-cm (kgf-cm, lbf-in)
k = 1.0 (1.0, 0.269)
R = 0.5Q1 + 0.25Q2 n/(n + 1) kN (tf, Ltf)
Q1 = total dynamic container load in longitudinal direction on cross deck box
beam (above the bottom of cross deck box beam), in kN (tf, Ltf)
= m1m2W(1 − h5/h4) (sin (0.5φ) + 0.5a1/g)
Q2 = total dynamic container load in longitudinal direction on transverse
bulkhead, (below the bottom of cross deck box beam), in kN (tf, Ltf)
= m1m2W(h5/h4) (sin (0.5φ) + 0.5a2/g)
C2 = 1.72 − 0.26n0.5 ≥ 1.0
b0 = width of the strength deck hatch opening amidships, in m (ft), as specified in
5C-5-4/7
n = number of vertical webs on transverse bulkhead under consideration
m1 = tier number of container stacks in the cargo hold amidships
m2 = row number of container stacks in the cargo hold amidships
h4 = m1hC
hC = height of container, in m (ft)
h5 = vertical distance between inner bottom and the bottom of cross deck box
beam at center line, amidships, in m (ft)
W = maximum design weight of an equivalent 40 ft container in hold, not to be
taken less than 274 kN (28 tf, 27.6 Ltf)
g = acceleration due to gravity = 9.807 m/sec2 (32.2 ft/sec2)
a1 = longitudinal acceleration al, as specified in 5C-5-3/5.5.1(c) at a vertical
height 0.5(h4 + h5), measured from inner bottom amidships, in m/sec2
(ft/sec2)

686 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

a2 = longitudinal acceleration al, as specified in 5C-5-3/5.5.1(c) at a vertical

height 0.5h5, measured from inner bottom amidships, in m/sec2 (ft/sec2)
φ = angle of pitch in degrees, as specified in 5C-5-3/5.5.1(a)
SM is as defined in 5C-5-4/17.5.2 with the following modification.
The following items may be included in the calculation of the section modulus SM:
• Strength deck plating and continuous longitudinals
• Side shell and longitudinal bulkhead plating and continuous longitudinals. Effective depth of
side shell and longitudinal bulkhead is equal to the distance between the strength deck and the
second deck, but not to be more than 0.22D
• Second deck plating and continuous longitudinals, if the distance between strength and second
decks does not exceed 0.22D as shown in 5C-5-4/Figure 4
• Continuous longitudinal hatch side coaming (plate and continuous longitudinal stiffeners)

17.7 Cross Deck Structure (1998)

17.7.1 Cross Deck Width
In general, the width of the cross deck box beam is not to be less than 0.04b0 for watertight
bulkhead and 0.03b0 for mid-hold strength bulkhead where b0 is as defined in 5C-5-4/7.
17.7.2 Cross Deck Plating
The net thickness of the cross deck plating at the strength deck level and at the bottom of the cross
deck box is not to be less than that obtained from the following equation:
t = kFo/(wfs) mm (in.)
but not to be taken less than 9.0 mm (0.35 in.).
where
k = 100 (100, 186.8)
Fo = F+R
F = C1(TM + Ts) ωM L02ICB/(b3αMΓM) kN (tf, Ltf)
C1 = 70/(9 + μ)
*
μ = 107 I CB /(b03l0)
*
I CB = 0.5(ICB1 + ICB2)
ICB1 and ICB2 = net moment of inertia of the cross deck box beam at the vessel’s centerline,
in m4 (ft4), fore and aft of the hatch opening amidships with respect to the
vertical axis z, (5C-5-4/Figure 4)
ICB = net moment of inertia of the cross deck box beam under consideration at the
vessel’s centerline, in m4 (ft4), about the vertical axis z (5C-5-4/Figure 4)
b = 0.5(B + b0)
b0 = width, in m (ft), of the strength deck hatch opening amidships, measured
between the inboard edges of the strength deck, as shown in 5C-5-4/Figure 4
l0 = length of the hatch opening amidships, in m (ft)
B = vessel’s breadth, in m (ft), amidships
w = width of the cross deck structure under consideration, in m (ft)

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

fs = permissible shear stress, in N/cm2 (kgf/cm2, lbf/in2)

= 0.45 Sm fy
Ts is as defined in 5C-5-3/3.1.

TM, ωM, L0, αM and ΓM are as defined in 5C-5-4/7.

R is as defined in 5C-5-4/17.5.3.
Sm and fy are as defined in 5C-5-4/11.3.1.

For cross deck structures abaft engine room, L0 may be taken as L0′, defined in 5C-5-4/9.3.2.
The net thicknesses t1 and t2 (5C-5-4/Figure 11) of the side plate of the cross deck box beam are
not to be less than the following:
t1 = L/50 + 6 mm (L/4170 + 0.24 in.), but need not be greater than 10 mm (0.39 in.)
t2 = 14 mm (0.55 in.)
where
L = length of vessel, in m (ft), as defined in 3-1-1/3.1
The following minimum extent a1 and a2 of insert plates, (5C-5-4/Figure 11) are provided as guidance:
a1 = 1.5br
a2 = 0.5bs
br = horizontal distance from the longitudinal bulkhead to the bracket end, as
shown in 5C-5-4/Figure 11
bs = width of the strength deck of the hull girder section under consideration, as
shown in 5C-5-4/Figure 11
The required net thickness t2 may be reduced, provided the strength of the resultant design is
verified by fine mesh finite element analyses, as specified in 5C-5-5/9.5 or 5C-5-5/9.7 with the
combined load cases 5C-5-3/9; however, in no case is the thickness to be taken less than t1,
obtained from the above equation.
The side plating above the strength deck is also to meet the requirement in 5C-5-4/19.1.1.
17.7.3 Cross Deck Beams
The net section modulus of each deck beam at the weather deck, in association with the effective
plating to which it is attached, is to be not less than that obtained from the following equations:
SM = M/fb cm3 (in3)

M = psl2103/k N-cm (kgf-cm, lbf-in)

where
k = 12 (12, 83.33)
s = spacing of deck beams
l = span of beam between effective supports, in m (ft)
p = nominal deck pressure, in N/cm2 (kgf/cm2, lbf/in2), as specified in
5C-5-3/Table 2.
fb = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.4 Sm fy
Sm and fy are as defined in 5C-5-4/11.3.1.

688 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

The effective breadth of plating, be, is as defined in 5C-5-4/11.3.1.

In general, the side plate of the cross deck box beam is to be horizontally stiffened. The net section
modulus of stiffeners is to be not less than as required for watertight bulkhead stiffeners in 5C-5-4/23.7
in the same location. Pressure is not to be taken less than 2.25 N/cm2 (0.23 kgf/ cm2, 3.27 lbf/in2).
17.7.4 Section Modulus of Cross Deck Box Beam
The net section modulus at any section of the cross deck box beam with respect to the vertical axis
z (5C-5-4/Figure 4) is not to be less than obtained from the following equation:
SM = M/fb cm3 (in3)
where
M = M1 + M2
M1 = kFz105 N-cm (kgf-cm, lbf-in)
M2 = k0.17C2Rb1 105 N-cm (kgf-cm, lbf-in)
k = 1.0 (1.0, 0.269)
C2 and R are as defined in 5C-5-4/17.5.3.
F is as defined in 5C-5-4/17.7.2.
b1 = width, in m (ft), of the hatch opening for the hull girder section under
consideration
z = horizontal distance from centerline of the vessel to the section of cross deck
box beam under consideration, in m (ft), as shown in 5C-5-4/Figure 4. z need
not be taken more than 0.5 b1
fb = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2) = 0.85 Sm fy
Sm and fy are as defined in 5C-5-4/11.3.1.
The following items may be included in the calculation of the cross deck box beam section modulus
SM:
• Transverse hatch coaming (above the strength deck)
• Cross deck plating with stiffeners at the strength deck level
• Bottom and top plating of the cross deck box beam with stiffeners
• Side plates of cross deck box beam with stiffeners, (between strength deck and bottom of the
cross deck box beam)

17.9 Longitudinal Deck Girders Inboard of Lines of Openings (1 July 2005)

The net scantlings of the longitudinal deck girders inside the lines of outer-most hatch openings are to
satisfy the following condition and, in general, are to be maintained throughout its length:
fL1/η ≤ fa1 and fL2 ≤ fa2
where
fL1 = Ho fLD1
fL2 = Ho fLD2
fLD1 = calculated longitudinal hull girder compressive stress at the top flange of the
longitudinal deck girder, in N/cm2 (kgf/cm2, lbf/in2)
= CMsv /SM

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

fLD2 = calculated maximum longitudinal hull girder bending stress at the top flange of the
longitudinal deck structures, in N/cm2 (kgf/cm2, lbf/in2)
= CMt /SM
Ho = effectiveness of longitudinal deck structures, as specified in 3-2-1/17.3
Msv = the maximum total vertical sagging bending moment amidships, in kN-m (tf-m, Ltf-ft),
but is to be taken not less than Mw (sagging), as specified in 5C-5-3/5.1.1. For this
purpose, Mw is to be calculated with kw defined in 5C-5-3/5.1.1.
Mt = total hull girder vertical bending moment, as specified in 5C-5-3/7.1.1, with ku = 1.0,
kc = 1.0 and kw defined in 5C-5-3/5.1.1, in kN-m (tf-m, Ltf-ft)
SM = the offered net design hull girder vertical section modulus amidships at the top flange
of the longitudinal deck girder, cm2-m (in2-ft)
C = 1000 (1000, 2240)
η = fE /fy for fE /fy ≤ 0.6

= (1 − 0.24 fy /fE) for fE /fy > 0.6

fa1 = Sm fy − fb N/cm2 (kgf/cm2, lbf/in2)
fa2 = 0.9Sm fy − fb N/cm2 (kgf/cm2, lbf/in2)
Sm = strength reduction factor for the longitudinal deck girders, as defined in 5C-5-4/11.3.1

fE = π2E/(l0/r)2 N/cm2 (kgf/cm2, lbf/in2)

E = modulus of elasticity of the material, may be taken as 2.06 × 107 N/cm2 (2.1 × 106
kgf/cm2, 30 × 106 lbf/in2) for steel
l0 = length of the strength deck hatch opening, in cm (in.)
r = least radius of gyration of the longitudinal deck girder, in cm (in.)
fb = bending stress, N/cm2 (kgf/cm2, lbf/in2). Where the longitudinal deck girder is
effectively supported by pillars, fb may be taken as zero
= M/SMv
M = bending moment of the longitudinal deck girder induced by container loads on deck,
in kN-cm (tf-cm, Ltf-in)
= cmd1md2Wdl0
c = 45 (45, 101.9) for a centerline longitudinal deck girder
= 30 (30, 67.2) for two longitudinal deck girders
md1 = tier number of 20 ft container stacks on deck
md2 = row number of 20 ft container stacks on deck
Wd = maximum design weight of a 20 ft container on deck, not to be taken less than 137.3 kN
(14 tf, 13.8 Ltf)
SMv = section modulus of the longitudinal deck girder about its horizontal neutral axis, in
cm3 (in3)
fy = specified minimum yield point of the longitudinal deck girders, in N/cm2 (kgf/cm2,
lbf/in2)

690 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

17.11 Deck Transverse in Underdeck Passageway (1998)

Deck transverses of the strength deck in the underdeck passageway are to have scantlings not less than that
obtained from the following equations:
17.11.1
The net section modulus of the deck transverse is not to be less than that obtained from the
following equation:
SM = M/fb cm3 (in3)

M = psl2105/k N-cm (kgf-cm, lbf-in)

where
k = 12 (12, 44.64)
p = nominal pressure in kN/m2 (tf/m2, Ltf/ft2), as specified in 5C-5-3/Table 2
s = spacing of the deck transverse, in m (ft)
l = span of the deck transverse, in m (ft)
l may be modified in accordance with 5C-5-4/Figure 9.
fb = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.7 Sm fy
Sm and fy are as defined in 5C-5-4/11.3.1.

17.11.2
The net section modulus of the deck transverse is not to be less than the section modulus of the
side transverse in 5C-5-4/15.5. The depth and the net web thickness of the deck transverse are also
not to be less than required for side transverse in 5C-5-4/15.3 nor for transverse web on
longitudinal bulkhead in 5C-5-4/21.11.

17.13 Underdeck Passageway (Second Deck) (1 July 2005)

The net thickness of the passage deck is to be not less than t1, as specified below:

t1 = 9.0 mm for L ≥ 200 m

t1 = 0.02 L + 5.0 mm for 200 m ≥ L ≥ 130 m
t1 = 0.354 in. for L ≥ 656 ft.
t1 = 0.00024 L + 0.20 in. for 656 ft > L ≥ 427 ft.
In addition, the net thickness of the longitudinally framed passage deck plate is to be not less than that
obtained from the following equation:
t2 = cs(Sm fy /E)1/2 mm (in.)
where
s = spacing of longitudinals, in mm (in.)
c = 0.7N2 − 0.2, not to be taken less than 0.2
N = Rd[(Q/Qd)(y/yn)]1/2
Rd = (SMRDS /SMD)1/2

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

SMRDS = reference net hull girder section modulus for sagging bending moment based on the
material factor of the strength deck flange of the hull girder, in cm2-m (in2-ft)
= 0.95SMS
SMS = reference gross hull girder section modulus in accordance with 5C-5-4/3.1.1 for
sagging total bending moment, with kw defined in 5C-5-3/5.1.1 for the purpose of
calculating Mw (sagging), based on the material factor of the strength deck flange of
the hull girder, in cm2-m (in2-ft)
SMD = net design hull girder section modulus amidships at the strength deck, in cm2-m (in2-ft)
Q, Qd = material conversion factor in 5C-5-4/5 for the side stringer plating, the bottom flange
and the strength deck flange of the hull girder, respectively
y = vertical distance, in m (ft), measured from the neutral axis of the hull girder transverse
section to the passage deck
yn = vertical distance, in m (ft), measured from the deck to the neutral axis of the hull
girder transverse section,
Sm and fy are defined in 5C-5-4/11.3.1.
The net thickness, t2, may be determined based on Sm and fy of the hull girder strength material required at
the location under consideration.
In addition, the passage deck forming a tank boundary is to comply with the requirement for a side stringer
in 5C-5-4/15.11. Where the passage deck forms a cargo hold boundary, the scantlings of the deck are also
to comply with the requirements for watertight longitudinal bulkhead in 5C-5-4/21.5 and 5C-5-4/21.7.

FIGURE 10
Definitions of h1 and h2
Strength Deck
= = =
= Second Deck = =

h1 h1 h1

LWL

h2 h2 h2

d d d

692 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

FIGURE 11
Sizes of Insert Plates

br

a1

t2

bs
t2

t1
a2 t2
t2

a2
t1

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

19 Hatch Coamings and Hatch Covers (1998)

19.1 Hatch Coamings

Hatch coamings are to satisfy the following requirements.
19.1.1 Thickness of Coamings
The net thickness of the coaming plates is to be not less than 10 mm (0.4 in.). Horizontal stiffeners
are to be fitted on coamings. Effective brackets or stays are to be fitted at intervals of not more
than 3.0 m (10 ft). Where coamings exceed 915 mm (36 in.) in height, the arrangement of stiffeners
and brackets, or stays is to provide equivalent strength and stiffness. Consideration is to be given
to provide additional strength for deep coamings fitted forward of 0.20L from the FP, which may
be subject to impact loading from green water.
Where chocks are provided on the coaming to limit the horizontal movement of hatch cover, the
strength of the coaming and deck structure is to be adequate to withstand the load on these chocks.
Similar consideration is to be given to pads supporting the load from hatch covers.
19.1.2 Continuous Longitudinal Hatch Coamings
Continuous longitudinal hatch coamings on the strength dec,k which extend more than 1/7L and
are effectively supported by underdeck structures, are to be longitudinally stiffened. The coaming
thickness is to be not less than the value of t3, given in 5C-5-4/17.1, adjusted for the spacing of the
coaming stiffeners and the material conversion factor. The stiffeners are to comply with the
requirements of 5C-5-4/17.3 where l is the distance between brackets. The hull girder section
modulus to the top of the coaming is to be as required by 5C-5-4/3.1.1 and 5C-5-4/3.1.3.

19.3 Hatch Covers (2002)

The strength and arrangements of hatch covers are generally to be determined in accordance with the
applicable parts of 3-2-15/7 and 3-2-15/9.
For container loading, the description of the container stowage arrangement including the exact locations
of the container pads, maximum design weight of a container and numbers of tiers and rows is to be submitted.
Where the pads are not in line with supporting structures, headers are to be provided to transmit the
container loads to these members. Each member intended to support containers is to meet the requirements
in 3-2-15/9.9.
For dynamic container loading, the container load is to be obtained from the equations in 5C-5-3/5.5.2(b)
with the maximum design container weight for load case 3, 5 and 7 specified in Item C in 5C-5-3/Table 1.

21 Longitudinal Bulkheads (1998)

21.1 Tank Bulkhead Plating (1 July 2005)

The net thickness of the longitudinal bulkhead plating forming tank boundaries, in addition to compliance
with 5C-5-4/5.5, is to be not less than t1 and t2, specified below:
t1 = 0.73s(k1 p/f1)1/2 mm (in.)
t2 = 0.73s(k2 p/f2)1/2 mm (in.)
but not less than 9.5 mm (0.37 in.) or L/60 + 6.0 mm (L/5000 + 0.24 in.), whichever is less.
where
s = spacing of longitudinal bulkhead longitudinals, in mm (in.)
k1 = 0.342
k2 = 0.500

694 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

p = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), at the lower edge of each plate, as
specified in 5C-5-3/Table 2.
f1 = permissible bending stress, in longitudinal direction, in N/cm2 (kgf/cm2, lbf/in2)
= 1.1[1.0 − 0.33(z/B) − 0.52α1(SMRB /SMB)(y/yn)]Sm fy ≤ 0.75Sm fy below neutral axis

= 1.1[1.0 − 0.33(z/B) − 0.52α2(SMRD /SMD)(y/yn)]Sm fy ≤ 0.75Sm fy above neutral axis

SMB /SMRB is not to be taken more than 1.2α1 or 1.4, whichever is less.
f2 = permissible bending stress, in the vertical direction in N/cm2 (kgf/cm2, lbf/in2)
= 0.90Sm fy
α1 = Sm1 fy1/Sm fy
α2 = Sm2 fy2/Sm fy
Sm = strength reduction factor of the longitudinal bulkhead plating, as defined in
5C-5-4/11.3.1
fy = minimum specified yield point of the longitudinal bulkhead plating, in N/cm2
(kgf/cm2, lbf/in2)
z = transverse distance, in m (ft), measured from the centerline of the section to the
longitudinal bulkhead strake under consideration
y = vertical distance, in m (ft), measured from the neutral axis of the hull girder transverse
section to the lower edge of the longitudinal bulkhead strake under consideration
yn = vertical distance, in m (ft), measured from the strength deck (bottom) to the neutral
axis of the section
L = vessel’s length, in m (ft), as defined in 3-1-1/3.1
B = vessel’s breadth, in m (ft), as defined in 3-1-1/5
SMRB, SMB, and E are as defined in 5C-5-4/11.3.1.
Sm1 and fy1 are as defined in 5C-5-4/11.5.
SMRD, Sm2 and fy2 are as defined in 5C-5-4/13.3.
SMD is as defined in 5C-5-4/13.1.
In general, the longitudinal bulkhead is to be longitudinally framed, except for the areas of 0.35D above
and below mid-depth of the longitudinal bulkhead. These areas of longitudinal bulkhead plating may be
transversely framed, provided the net thickness of the longitudinal bulkhead plating is not less than t, as
specified below:
t = 0.73sk(k2 p/f)1/2 mm (in.)
where
s = spacing of vertical stiffener on the longitudinal bulkhead, in mm (in.)
k = (3.075(α)1/2 − 2.077)/(α + 0.272), (1 ≤ α ≤ 2)
= 1.0 (α > 2)
α = aspect ratio of the panel (longer edge/shorter edge)
f = permissible bending stress, in longitudinal direction, in N/cm2 (kgf/cm2, lbf/in2)
= 1.2[1.0 − 0.33(z/B) − 0.52α1(SMRB /SMB)(y/yn)]Sm fy ≤ 0.85Sm fy below neutral axis
= 1.2[1.0 − 0.33(z/B) − 0.52α2(SMRD /SMD)(y/yn)]Sm fy ≤ 0.85Sm fy above neutral axis
All other parameters are as defined above.

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

Flats forming recesses or steps in the longitudinal bulkhead are also to be of not less net thickness than
required for the side stringer in 5C-5-4/15.11.1.
In addition to the above tank requirements, the longitudinal bulkhead forming the cargo hold boundary is
to comply with the requirements in 5C-5-4/21.5 for watertight bulkheads.
In addition to the above requirements, the net thickness of the longitudinally framed strakes is also to be
not less than that obtained from the following equation:
t3 = cs(Sm fy /E)1/2 mm (in.)
where
s = spacing of longitudinal bulkhead longitudinals, in mm (in.)
c = 0.7N2 − 0.2, not to be less than 0.2
c for the top strake is not to be taken less than 0.4Q1/2.
N = Rd(Q/Qd)1/2 for the top strake
= Rd[(Q/Qd)(y/yn)]1/2 for other locations above neutral axis
= Rb[(Q/Qb)(y/yn)]1/2 for locations below neutral axis
Rd = (SMRDS /SMD)1/2
Rb = (SMRBH /SMB)1/2
SMRDS = reference net hull girder section modulus for sagging bending moment based on the
material factor of the strength deck flange of the hull girder, in cm2-m (in2-ft)
= 0.95SMs
SMs = reference gross hull girder section modulus in accordance with 5C-5-4/3.1.1, for
sagging total bending moment, with kw defined in 5C-5-3/5.1.1 for the purpose of
calculating Mw (sagging), based on material factor of the strength deck flange of the
hull girder, in cm2-m (in2-ft)
SMRBH = reference net hull girder section modulus for hogging bending moment based on the
material factor of the bottom flange of the hull girder, in cm2-m (in2-ft)
= 0.9SMH
SMH = reference gross hull girder section modulus in accordance with 5C-5-4/3.1.1 for
hogging total bending moment, with kw defined in 5C-5-3/5.1.1 for the purpose of
calculating Mw (hogging), based on the material factor of the bottom flange of the
hull girder, in cm2-m (in2-ft)
Q, Qb, Qd = material conversion factor in 5C-5-4/5 for the bulkhead plating, the bottom flange
and the strength deck flange of the hull girder, respectively
y = vertical distance, in m (ft), measured from the neutral axis of the hull girder transverse
section to the lower edge (upper edge) of the bulkhead strake, when the strake under
consideration is below (above) the neutral axis.
yn = vertical distance, in m (ft), measured from the bottom (deck) to the neutral axis of the
hull girder transverse section, when the strake under consideration is below (above)
the neutral axis
Sm and fy are defined in 5C-5-4/21.1 and E is defined in 5C-5-4/11.3.1.
The net thickness, t3, may be determined based on Sm and fy of the hull girder strength material required at
the location under consideration.

696 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

The minimum width of the top strake for the midship 0.4L is to be obtained from the following equations:
b = 5L + 800 mm for L ≤ 200 m
= 0.06L + 31.5 in. for L ≤ 656 ft
b = 1800 mm for 200 < L ≤ 500 m
= 70.87 in. for 656 < L ≤ 1640 ft
L = length of vessel as defined in 3-1-1/3.1, in m (ft)
b = width of top strake, in mm (in.)

21.3 Tank Bulkhead Longitudinals/Stiffeners (1 July 2005)

The net section modulus of each longitudinal or each vertical stiffener on the longitudinal bulkhead and
double bottom water-tight girder forming tank boundaries, in association with the effective plating to which it
is attached, is to be not less than that obtained from the following equations:
SM = M/fb cm3 (in3)

M = c1c2 psl2103/k N-cm (kgf-cm, lbf-in)

where
k = 12 (12, 83.33)
c1 = 1.0 for longitudinals

= 1 + γl/10p for vertical stiffeners

γ = specific weight of the liquid ≥ 1.005 N/cm2-m (0.1025 kgf/cm2-m, 0.444 lbf/in2-ft)
c2 = 1.0 without struts
= 0.65 with effective struts
s = spacing of longitudinals or vertical stiffeners, in mm (in.)
l = span of longitudinals or vertical stiffeners between effective supports, as shown in
5C-5-4/Figure 6, in m (ft)
p = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), at the longitudinal considered, as
specified in 5C-5-3/Table 2. For vertical stiffeners, pressure is to be taken at the
midspan of each stiffener.
fb = permissible bending stresses, in N/cm2 (kgf/cm2, lbf/in2)

= 1.15[1.0 − 0.33(z/B) − 0.52α1(SMRB /SMB)(y/yn)]Sm fy ≤ 0.80Sm fy

for longitudinals on the longitudinal bulkhead below neutral axis
= 1.3[1.0 − 0.33(z/B) − 0.52α2(SMRD /SMD)(y/yn)]Sm fy ≤ 0.80Sm fy
for longitudinals on the longitudinal bulkhead above neutral axis
= 1.4[1.0 − 0.33(z/B) − 0.52(α1SMRB /SMB)(y/yn)]Sm fy ≤ 0.80Sm fy
for longitudinals on the double bottom tight girders
= 0.90 Sm fy for vertical stiffeners
y = vertical distance, in m (ft), measured from the neutral axis of the hull girder transverse
section to the longitudinal under consideration at its connection to the associated plate

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

SMRB and SMB are as defined in 5C-5-4/11.3.1.

Sm1 and fy1 are as defined in 5C-5-4/11.5.
SMRD, Sm2 and fy2 are as defined in 5C-5-4/13.3.
SMD is as defined in 5C-5-4/13.1.
Sm, fy, α1, α2, z, and yn are defined in 5C-5-4/21.1.
The effective breadth of plating, be, is as defined in 5C-5-4/11.5.
Where side struts are fitted as an effective supporting system for side tank structures, the requirement for
the vertical stiffeners on the longitudinal bulkhead is also to be not less than 90% of the side frame
requirement in 5C-5-4/13.3.
Longitudinals or horizontal stiffeners on the flats forming recesses or steps in the longitudinal bulkhead are
to comply with the requirements for stiffeners on the side stringer in 5C-5-4/15.11.2.
In addition to the above tank requirements, the longitudinal bulkhead forming a cargo hold boundary is to
comply with the requirements in the following subsection for the watertight bulkhead.

21.5 Watertight Bulkhead Plating (1 July 2005)

The net thickness of the longitudinal bulkhead plating forming cargo hold boundaries, in addition to
compliance with 5C-5-4/5.5, is to be not less than t1 and t2, specified below:
t1 = 0.73s(k1p/f1)1/2 mm (in.)
t2 = 0.73s(k2p/f2)1/2 mm (in.)
but not less than 9.0 mm (0.354 in.) or L/60 + 4.0 mm (L/5000 + 0.157 in.), whichever is less.
where
s = spacing of longitudinals or vertical stiffeners, in mm (in.)
k1 = 0.342 for longitudinally stiffened plating

= 0.500k2 for vertically stiffened plating

k2 = 0.500
p = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), at the lower edge of each plate, as
specified in 5C-5-3/Table 2. Pressure is not to be taken less than 2.25 N/cm2
(0.23 kgf/cm2, 3.27 lbf/in2).
f1 = permissible bending stress, in longitudinal direction, in N/cm2 (kgf/cm2, lbf/in2)

= [1.0 − 0.33(z/B) − 0.52α1(SMRB/SMB)(y/yn)]Sm fy ≤ 0.75Smfy below neutral axis

= [1.0 − 0.33(z/B) − 0.52α2(SMRD/SMD)(y/yn)]Sm fy ≤ 0.75Smfy above neutral axis

SMB/SMRB is not to be taken more than 1.2α1 or 1.4, whichever is less.

f2 = permissible bending stress, in the vertical direction in N/cm2 (kgf/cm2, lbf/in2)
= 0.85 Sm fy
All other parameters are defined in 5C-5-4/21.1.
In addition to the above requirement, the required net thickness t3 of the longitudinally framed strakes and
the minimum width of the top strake for the midship 0.4L are to be obtained from 5C-5-4/21.1.

698 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

21.7 Watertight Bulkhead Longitudinals/Stiffeners (1 July 2005)

The net section modulus of each longitudinal or vertical stiffener on the longitudinal bulkhead forming
cargo hold boundaries, in association with the effective plating to which it is attached, is to be not less than
that obtained from the following equations:
SM = M/fb cm3 (in3)

M = c1c2 psl2103/k N-cm (kgf-cm, lbf-in)

where
p = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), at the longitudinal considered, as
specified in 5C-5-3/Table 2. For vertical stiffeners, pressure is to be taken at the
midspan of each stiffener. Pressure is not to be taken less than 2.25 N/cm2
(0.23 kgf/cm2, 3.27 lbf/in2).
fb = permissible bending stresses, in N/cm2 (kgf/cm2, lbf/in2)

= 1.2[1.0 − 0.33(z/B) − 0.52α1(SMRB /SMB)(y/yn)]Sm fy ≤ 0.85Sm fy

for longitudinals below neutral axis
= 1.35[1.0 − 0.33(z/B) − 0.52α2(SMRD /SMD)(y/yn)]Sm fy ≤ 0.85Sm fy
for longitudinals above neutral axis
= 0.95Sm fy for vertical stiffeners
All other parameters are as defined in 5C-5-4/21.3 above.

21.9 Longitudinals in Upper Wing Torsional Box

The net section modulus of longitudinals on the longitudinal bulkhead forming the upper wing torsional
box is to be not less than as required for watertight bulkhead longitudinals in 5C-5-4/21.7 above in the
same location. Pressure is not to be taken less than 2.25 N/cm2 (0.23 kgf/cm2, 3.27 lbf/in2). In addition, the
net moment of inertia of longitudinals on the longitudinal bulkhead, within the region of 0.1D from the strength
deck, in association with the effective plating (bWL tn), is to be not less than io, as specified in 5C-5-4/13.3.

21.11 Transverse Web on Longitudinal Bulkhead in Underdeck Passageway (1 July 2005)

Transverse webs on the longitudinal bulkhead in the underdeck passageway are to have scantlings not less
than that obtained from the following equations.
21.11.1 Section Modulus of Web
The net section modulus of the side transverse web on the longitudinal bulkhead is not to be less
than that obtained from the following equation:
SM1 = M/fb1 cm3 (in3)
SM2 = M2/fb2 cm3 (in3)

M1 = pusl2105/k1 N-cm (kgf-cm, lbf-in)

M2 = k8λγ1 phs1 y N-cm (kgf-cm, lbf-in)

where
k1 = 12 (12, 44.64)
pu = nominal pressure for flooding condition calculated at the mid-span of the
transverse web under consideration, in kN/m2 (tf/m2, Ltf/ft2), as specified in
5C-5-3/Table 2. Pressure is not to be taken less than 22.5 kN/m2 (2.3 tf/m2,
0.21 Ltf/ft2)

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

s = spacing of the transverse webs, in m (ft)

l = span of the transverse web, in m (ft)
l may be modified in accordance with 5C-5-4/Figure 9
y = k2hu/2
k2 = 100 (100, 12)
hu = height of the underdeck passageway, in m (ft)
fb1 = permissible bending stress, in N/cm2 (kgf/cm2 lbf/in2)
= 0.85 Sm fy
fb2 = permissible bending stress, in N/cm2 (kgf/cm2 lbf/in2)
= 0.85 Sm fy
Sm and fy are as defined in 5C-5-4/11.3.1.

k, λ, γ1, p, h and s1 are as defined in 5C-5-4/15.1.

21.11.2 Depth of Web

The depth of the transverse web is not to be less than that obtained from the following equation:
d = kl mm (in.)
where
k = 125 (1.5)
l is as defined in 5C-5-4/21.11.1 above.
21.11.3 Web Thickness
The net web thickness of the transverse web is not to be less than that obtained from the following
equations:
t1 = k3F1/(dw fs) mm (in.)
t2 = k3F2/(dw fs) mm (in.)
but not less than 8.0 mm (0.31 in.)
F1 = k500pusl N (kgf, lbf)
where
k3 = 10 (10, 1.0)
k = 1.0 (1.0, 2.24)
fs = permissible shear stress, in N-cm2 (kgf-cm2, lbf-in2)
= 0.50 Sm fy
dw = depth of the side transverse, in cm (in.)

pu, s and l are as defined in 5C-5-4/21.11.1 above. F2 is as defined in 5C-5-4/15.5.3.

700 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

23 Transverse Bulkheads – Plating and Stiffeners (1998)

23.1 Tank Bulkhead Plating (2007)

The net thickness of transverse bulkhead plating forming tank boundaries is to be not less than t, as specified
below:
t = 0.73sk(k1 p/f)1/2 mm (in.)
but not less than 9.0 mm (0.35 in.) or L/60 + 5.0 mm (L/5000 + 0.20 in.), whichever is less.
where
s = spacing of bulkhead stiffeners, in mm (in.)
k1 = 0.500

k = (3.075(α)1/2 − 2.077)/(α + 0.272), (1 ≤ α ≤ 2)

= 1.0, (α > 2)
α = aspect ratio of the panel (longer edge/shorter edge)
p = nominal pressure, N/cm2 (kgf/cm2, lbf/in2), at the lower edge of each plate, as
specified in 5C-5-3/Table 2 for transverse bulkhead members
f = permissible bending stress
= 0.95 Sm fy, in N/cm2 (kgf/cm2, lbf/in2)
L = vessel’s length, in m (ft), as defined in 3-1-1/3.1
Sm and fy are as defined in 5C-5-4/11.3.1.
In addition to the above tank requirements, the transverse bulkhead forming a cargo hold boundary is to
comply with the requirements in 5C-5-4/23.5 for the watertight bulkhead.

23.3 Tank Bulkhead Stiffeners

The net section modulus of each individual vertical/horizontal stiffener on the transverse bulkheads forming
tank boundaries and tank end floors, in association with the effective plating, is to be not less than that obtained
from the following equation:
SM = M/fb cm3 (in3)

M = c1 psl2103/k N-cm (kgf-cm, lbf-in)

where
k = 12 (12, 83.33)
c1 = 1.0 for horizontal stiffeners
= 1 + γl/10p for vertical stiffeners
γ = specific weight of the liquid, 1.005 N/cm2-m (0.1025 kgf/cm2-m, 0.444 lbf/in2-ft)
s = spacing of vertical/horizontal stiffeners, in mm (in.)
l = span of stiffeners between effective supports, in m (ft)
p = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), at the stiffener considered, as specified
in 5C-5-3/Table 2. For vertical stiffeners, pressure is to be taken at the midspan of
each stiffener.
fb = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.70 Sm fy
Sm and fy are as defined in 5C-5-4/11.3.1.

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

23.5 Watertight Bulkhead Plating (1 July 2005)

The net thickness of transverse bulkhead plating forming cargo hold boundaries is to be not less than t, as
specified below:
t = 0.73sk(k1 p/f )1/2 mm (in.)
but not less than 9.0 mm (0.354 in.) or L/60 + 4.0 mm (L/5000 + 0.157 in.), whichever is less.
where
s = spacing of bulkhead stiffeners, in mm (in.)
k1 = 0.50

p = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), at the lower edge of each plate, as
specified in 5C-5-3/Table 2. Pressure is not to be taken less than 2.25 N/cm2
(0.23 kgf/cm2, 3.27 lbf/in2).
f = permissible bending stress
= 0.85 Sm fy, in N/cm2 (kgf/cm2, lbf/in2)
All other parameters are as defined in 5C-5-4/23.1 above.

23.7 Watertight Bulkhead Stiffeners (1 July 2005)

The net section modulus of each individual vertical/horizontal stiffener on the transverse bulkheads in
cargo hold, in association with the effective plating to which they are attached, is to be not less than that
obtained from the following equation:
SM = M/fb cm3 (in3)

M = c1 psl2103/k N-cm (kgf-cm, lbf-in)

where
p = nominal pressure, in N/cm2 (kgf/cm2, lbf/in2), at the longitudinal considered. as
specified in 5C-5-3/Table 2. For vertical stiffeners, pressure is to be taken at the
mid-span of each stiffener. Pressure is not to be taken less than 2.25 N/cm2
(0.23 kgf/cm2, 3.27 lbf/in2).
fb = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= Sm f y
All other parameters are as defined in 5C-5-4/23.3 above.

23.9 Underdeck Passageway (1998)

In a case where watertight transverse bulkheads are provided within the underdeck passageway, their
scantlings are to be not less than required for watertight transverse bulkheads in cargo hold in 5C-5-4/23.5
and 5C-5-4/23.7.

25 Watertight Bulkhead Main Supporting Members (1998)

25.1 Transverse Watertight Bulkhead (1 July 2005)

For the service conditions with dynamic container load and relative displacements due to torsion, the minimum
scantlings for the horizontal girders and vertical webs on the watertight bulkheads are to be determined in
accordance with the subsequent paragraphs of this Section. Alternatively, these scantlings may be determined
from the total strength assessment in Section 5C-5-5. However, in no case are the scantlings to be taken
less than 85% of those determined from the corresponding equations below for the service conditions.

702 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

For the flooding conditions, the minimum scantlings for the horizontal and vertical webs on the watertight
bulkhead are to be determined in accordance with the subsequent paragraphs of this Section. Alternatively,
the horizontal and vertical webs may also be evaluated using a finite element model in conjunction with
the design flooding pressures specified in 5C-5-3/Table 2 and the corresponding permissible bending and
shear stresses in this Section. The mesh size of the finite element model should be sufficiently refined so
that the openings in the horizontal girders and vertical webs can be properly modeled. For container
carriers over 250 m in length, the watertight bulkhead main supporting members are to be evaluated by a
finite element model.
25.1.1 Section Modulus of Horizontal Girder
The net section modulus of horizontal girders on watertight bulkheads is not to be less than SM1
and SM2, as defined below, whichever is greater (see also 5C-5-4/1.3):
SM1 = (M1 + M2)/fb1 cm3 (in3)
SM2 = M3/fb2 cm3 (in3)

M1 = k110,000c2 Pllb N-cm (kgf-cm, lbf-in)

M2 = k26,000EIδc3/ l2b N-cm (kgf-cm, lbf-in)

M3 = k110,000c2 ps l2b N-cm (kgf-cm, lbf-in)

where
k1 = 1.0 (1.0, 0.269)
k2 = 1.0 (1.0, 2.24)
Pl = dynamic container load in longitudinal direction on horizontal girder, in kN
(tf, Ltf)
= Q/(n + 1)
n = number of the horizontal girders
Q = m1m2W(lv /h4) (sin (0.5φ) + 0.5al/g)

φ = angle of pitch, in degrees, as specified in 5C-5-3/5.5.1(a)

al = longitudinal acceleration, as specified in 5C-5-3/5.5.1(c) at the mid-span of
the vertical web of span lv, in m/sec2 (ft/sec2)
lv = span of vertical web, in m (ft), as defined in 5C-5-4/Figure 12 and
5C-5-4/Figure 13, as applicable
lb = span of the horizontal girders measured between the longitudinal bulkheads,
in m (ft), as defined in 5C-5-4/Figure 12 and 5C-5-4/Figure 13, as applicable
p = pressure for flooding condition calculated at the mid-span of the horizontal
girder under consideration, in kN/m2 (tf/m2, Ltf/ft2), as specified in
5C-5-3/Table 2
s = spacing of the horizontal girders under consideration, in m (ft)
δ = relative displacement in longitudinal direction due to torsion at both ends of
horizontal girder under consideration, in cm (in.)
= 60Cn(TM + TS)L02ωM (yh − db)/[EαMΓM (D − db)]
TM = nominal wave-induced torsional moment amidships, in kN (tf-m, Ltf-ft), as
defined in 5C-5-3/5.1.5
TS = still-water torsional moment amidships, in kN (tf-m, Ltf-ft), as specified in
5C-5-3/3.1

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

yh = vertical distance from baseline to the horizontal girder under consideration,

in m (ft)
db = depth of the double bottom, in m (ft)
D = vessel’s depth, in m (ft), as defined in 3-1-1/7
c2 = 0.316α2 for α < 0.5

= 0.204α2 + 0.028 for 0.5 ≤ α ≤ 1.0

= 0.077α + 0.16 for α > 1.0
c2 is not to be taken less than 0.05

α = 0.9(lv/lb) [(I/Iv)(sv/s)]1/4
if more than one vertical web is fitted on the bulkhead, average values of lv,
sv and Iv are to be used when these values are not the same for each web.
sv = spacing of vertical webs, in m (ft)

I = moment of inertia of the horizontal girder at the mid-span, in m4 (ft4)

Iv = moment of inertia of the vertical web at the mid-span, in m4 (ft4)

c3 = 2z/lb, ≥ 0.4
z = horizontal distance from the mid-span of the horizontal girder to the location
under consideration, in m (ft), as defined in 5C-5-4/Figure 12 or
5C-5-4/Figure 13
E = modulus of elasticity of the material, may be taken as 2.06 × 108 kN/m2
(2.1 × 107 tf/m2, 1.92 × 106 Ltf/ ft2) for steel
fb1 = permissible bending stress for service conditions, in N/cm2 (kgf/cm2, lbf/in2)
= 0.70 Sm fy
fb2 = permissible bending stress for flooding condition, in N/cm2 (kgf/cm2, lbf/in2)
= 0.95 Sm fy
Cn, αM, ΓM and ωM are as defined in 5C-5-4/7.
L0 is as defined in 5C-5-4/9.3.
m1, m2, W, h4 and g are as defined in 5C-5-4/17.5.3.
Sm and fy are as defined in 5C-5-4/11.3.1.

25.1.2 Web Sectional Area of Horizontal Girder

The net sectional area of the web portion of horizontal girders on watertight bulkheads is not to be
less than A1 and A2, as defined below, whichever is greater (see also 5C-5-4/1.3);
A1 = (F1 + F2)/fs1 cm2 (in2)
A2 = F3/fs2 cm2 (in2)
F1 = k2500cFPl N (kgf, lbf)

F2 = k120EIδ/ l 3b N (kgf, lbf)

F3 = k2500cF pslb N (kgf, lbf)

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

where
k = 1.0 (1.0, 18.67)
cF = 0.51α − 0.01 for α < 0.7

= 0.42α1/2 for 0.7 ≤ α

cF is not to be taken less than 0.25.
fs1 = permissible shear stress for service conditions, in N/cm2 (kgf/cm2, lbf/in2)
= 0.45 Sm fy
fs2 = permissible shear stress for flooding condition, in N/cm2 (kgf/cm2, lbf/in2)
= 0.54 Sm fy
Sm and fy are as defined in 5C-5-4/11.3.1.

k2, α, Pl, p, s, lb, E, I and δ are as defined in 5C-5-4/25.1.1 above.

25.1.3 Section Modulus of Vertical Web

The net section modulus of vertical webs on watertight bulkheads is not to be less than that obtained
from the following equation (see also 5C-5-4/1.3):
SM = M/fb cm3 (in3)

M = k110,000cM psv l v2 N-cm (kgf-cm, lbf-in)

where
k1 = 1.0 (1.0, 0.269)
lv = span of vertical web, in m (ft), as defined in 5C-5-4/Figure 12 and
5C-5-4/Figure 13, as applicable
sv = spacing of vertical webs, in m (ft)
p = pressure for flooding condition calculated at the mid-span of the vertical web
under consideration, in kN/m2 (tf/m2, Ltf/ft2), as specified in 5C-5-3/Table 2
cM = 0.637 for bulkhead without horizontal girder

= 0.637 − 0.4α ≥ 0.35 for bulkhead with horizontal girder

α = as defined in 5C-5-4/25.1.1, except that the value of s, lb and I are to be
averaged in case more than one horizontal girder is fitted on bulkhead
fb = permissible bending stress for flooding condition, in N/cm2 (kgf/cm2, lbf/in2)
= 0.95 Sm fy
Sm and fy are as defined in 5C-5-4/11.3.1.

25.1.4 Web Sectional Area of Vertical Web

The net sectional area of the web portion of vertical webs on watertight bulkheads is not to be less
than obtained from the following equation (see also 5C-5-4/1.3):
A = F/fs cm2 (in2)

F = k2600c1c2 psvlv N (kgf, lbf)

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

where
c1 = 0.678 for bulkhead without horizontal girder

= 0.678 − 0.36α, ≥ 0.45 for bulkhead with horizontal girder

c2 = 1 − 0.4y/lv
y = vertical distance from the lower end of the vertical web to the location under
consideration, in m (ft), as defined in 5C-5-4/Figure 12 or 5C-5-4/Figure 13
fs = permissible shear stress for flooding condition, in N/cm2 (kgf/cm2, lbf/in2)
= 0.54 Sm fy
Sm and fy are as defined in 5C-5-4/11.3.1.

lv , sv, p and α are as defined in 5C-5-4/25.1.3 above.

k2 is as defined in 5C-5-4/25.1.1 above.

25.3 Mid-hold Strength Bulkhead

Where fitted in accordance with 3-2-9/1.7, mid-hold strength bulkheads are to meet the following requirements.
The requirements of the net section modulus and net sectional area for horizontal girders and vertical webs
may be reduced, provided the strength of the resultant design is verified with the subsequent total strength
assessment in Section 5C-5-5. However, in no case are they to be taken less than 85% of those determined
from the following equations.
25.3.1 Section Modulus of Horizontal Girder
The net section modulus of horizontal girders on mid-hold strength bulkheads is not to be less than
obtained from the following equation (see also 5C-5-4/1.3):
SM = (M1 + M2)/fb cm3 (in3)

M1 = k110,000c2Pllb N-cm (kgf-cm, lbf-in)

M2 = k26,000EIδc3/ l b2 N-cm (kgf-cm, lbf-in)

where
fb = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.75Sm fy − 1,000Pt /A
Pt = dynamic container load in transverse direction on horizontal girder, in kN
(tf, Ltf)
= c4Qt /(n + 1)
c4 = 0.5 + z/lb
n = number of the horizontal girders
Qt = m1(m2 − 1)W(lv /h4)(sin (0.5θ) + 0.5at /g)
θ = angle of roll at LWL draft, in degrees, as specified in 5C-5-3/5.5.1(b)
at = transverse acceleration amidships, as specified in 5C-5-3/5.5.1(c) at the mid-
span of vertical web of span lv for wave heading of 60°, in m/sec2 (ft/sec2)
A = net cross sectional area of the horizontal girder, in cm2 (in2)
Sm and fy are as defined in 5C-5-4/11.3.1.
m1, m2, W, h4 and g are as defined in 5C-5-4/17.5.3.
k1, k2, Pl, lb, lv, E, I, δ, c2, c3 and z are as defined in 5C-5-4/25.1.1 above.

706 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

25.3.2 Web Sectional Area of Horizontal Girder

The net sectional area of the web portion of horizontal girders on mid-hold strength bulkheads is
not to be less than that obtained from the following equation (see also 5C-5-4/1.3):
A1 = (F1 + F2)/fs cm2 (in2)
F1 = k2500cFPl N (kgf, lbf)

F2 = k120EIδ/ l 3b N (kgf, lbf)

where
fs = permissible shear stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.45 Sm fy
Sm and fy are as defined in 5C-5-4/11.3.1.

k2, Pl, lb, E, I and δ are as defined in 5C-5-4/25.1.1 above.

k and cF are as defined in 5C-5-4/25.1.2 above.

25.3.3 Section Modulus of Vertical Web

The net section modulus of the vertical web on mid-hold strength bulkheads is not to be less than
that obtained in 5C-5-4/25.3.3(a) and 5C-5-4/25.3.3(b) below.
25.3.3(a) Section Modulus Parallel to Transverse Section. The net section modulus of the vertical
web on mid-hold strength bulkheads, about the neutral axis parallel to the transverse section of the
vessel, is not to be less than that obtained from the following equation (see also 5C-5-4/1.3):
SM = M/fb cm3 (in3)

M = k110,000cMPllv N-cm (kgf-cm, lbf-in)

where
Pl = dynamic container load in longitudinal direction on vertical web, in kN (tf, Ltf)
= Ql/(n + 1)
n = number of the vertical webs
Ql = m1m2W(lv/h4)[sin (0.71φ) + 0.5al/g]

φ = angle of pitch, in degrees, as specified in 5C-5-3/5.5.1(a).

al = longitudinal acceleration, as specified in 5C-5-3/5.5.1(c), at the mid-span of
the vertical web, in m/sec2 (ft/sec2)
fb = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)

= 0.75Sm fy − 1,000Pv /A
Pv = static and dynamic container load in vertical direction on vertical web, in kN
(tf, Ltf)
= Qv /(n + 1)

Qv = md1md2Wd(1 + 0.57av /g)(lb/B)

md1 = tier number of container stacks on deck
md2 = row number of container stacks on deck

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Section 4 Initial Scantling Criteria 5C-5-4

Wd = maximum design weight of an equivalent 40 ft container on deck, not to be

taken less than 176.5 kN (18 tf, 17.7 Ltf)
av = vertical acceleration amidships, as specified in 5C-5-3/5.5.1(c) for wave
heading angle of 0°, in m/sec2 (ft/sec2)
A = net sectional area of the vertical web, in cm2 (in2)
B = breadth of vessel, in m (ft), as defined in 3-1-1/5.
Sm and fy are as defined in 5C-5-4/11.3.1.
m1, m2, W, h4 and g are as defined in 5C-5-4/17.5.3.

k1 and lb are as defined in 5C-5-4/25.1.1 above.

cM and lv are as defined in 5C-5-4/25.1.3 above.

25.3.3(b) Section Modulus Parallel to Longitudinal Section. The net section modulus of the vertical
web, about the neutral axis parallel to the center line of the vessel, is not to be less than that obtained
from the following equation (see also 5C-5-4/1.3):
SM = M/fb cm3 (in3)

M = k1cPt1lv1 N-cm (kgf-cm, lbf-in)

where
k1 = 1.0 (1.0, 0.269)
lv1 = span of vertical web between adjacent horizontal girders, in m (ft), as defined
in 5C-5-4/Figure 12 and 5C-5-4/Figure 13 for bulkhead with horizontal girders
= lv for bulkhead without horizontal girder
c = 12500 where two (2) containers are located between adjacent
horizontal girders
= 22200 where three (3) containers are located between adjacent
horizontal girders
= 8330(m1 − 1) where there is no horizontal girder
Pt1 = W[sin (0.71θ) + 0.64at /g], in kN (tf, Ltf)

θ = angle of roll at LWL draft, in degrees, as specified in 5C-5-3/5.5.1(b)

at = transverse acceleration amidships, as specified in 5C-5-3/5.5.1(c) at the level
of the mid-span lv1 of vertical web of span, lv1 for wave heading angle of
90°, amidships, in m/sec2 (ft/sec2)
fb = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.80 Sm fy
m1, W and g are as defined in 5C-5-4/17.5.3.
Sm and fy are as defined in 5C-5-4/11.3.1.

708 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

25.3.4 Web Sectional Area of Vertical Web

The net sectional area of the web portion of the vertical web on mid-hold strength bulkhead is not
to be less than that obtained from the following equation, (see also 5C-5-4/1.3):
A = F/fs cm2 (in2)
F = k2500c1Pl N (kgf, lbf)
where
fs = permissible shear stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.45 Sm fy
Sm and fy are as defined in 5C-5-4/11.3.1.
k2 is as defined in 5C-5-4/25.1.1 above.
c1 is as defined in 5C-5-4/25.1.4 above.
Pl is as defined in 5C-5-4/25.3.3(a) above.

25.5 Minimum Thickness and Stiffening Arrangement of Webs

The net thickness of the web plate of the main supporting members is to be not less than 8.5 mm (0.33 in.).
Suitable stiffening arrangements are to be considered based on the structural stability of the web plates.
Tripping brackets are to be fitted at intervals of about 3 m (10 ft).

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 4 Initial Scantling Criteria 5C-5-4

FIGURE 12
Transverse Watertight and Mid-hold Strength Bulkhead
Definition of Spans for Bulkhead without Bottom Stool

cross deck box beam

lb

lv lv lv1

y
lb

CL

FIGURE 13
Transverse Watertight and Mid-hold Strength Bulkhead
Definitions of Spans for Bulkhead with Bottom Stool

cross deck box beam

lb

lv lv1

inner bottom

CL

710 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
PART Section 5: Total Strength Assessment

5C
CHAPTER 5 Vessels Intended to Carry Containers (130 meters
(427 feet) to 450 meters (1476 feet) in Length)

SECTION 5 Total Strength Assessment (1998)

1 General Requirements

1.1 General (1998)

When assessing the adequacy of the structural configuration and the initially selected scantlings, the
strength of the hull girder and the individual structural member or element is to be in compliance with the
failure criteria specified in 5C-5-5/3, 5C-5-5/5 and 5C-5-5/7 below. In this regard, the structural response
(load effects) is to be calculated by performing a structural analysis as specified in 5C-5-5/9 or by other
equivalent and effective means. Due consideration is to be given to structural details as given in 5C-5-5/1.7.

1.3 Loads and Load Cases (1998)

In the determination of the structural response, the combined load cases given in 5C-5-3/9.3 are to be
considered. Bottom slamming, bowflare slamming and other loads, as specified in 5C-5-3/11 and 5C-5-3/13,
are also to be considered, as necessary.

1.5 Stress Components (1998)

The total stress in stiffened plate panels of the hull girder can be divided into the following three categories:
1.5.1 Primary
Primary stresses are those resulting from hull girder bending. The primary bending stresses may
be determined by simple beam theory, using the specified total vertical and horizontal wave
bending moments and the effective hull girder section modulus at the section considered. These
primary stresses, designated by fL1 (fL1V, fL1H for vertical and horizontal bending, respectively),
may be regarded as uniformly distributed across the thickness of plate elements at the same level,
measuring from the relevant neutral axis of the hull girder.
In addition, warping stresses in the longitudinal direction, fLW, are also to be considered for the
deck structures, as specified in this Section.
1.5.2 Secondary
Secondary stresses are those resulting from bending of large stiffened panels between longitudinal
and transverse bulkheads due to local loads. The secondary bending stresses designated by fL2 or
fT2 are to be determined by performing a 3D FEM analysis, as outlined in this section.
For longitudinally stiffened hull structures, there is another secondary stress corresponding to
bending of longitudinals with the associated plating between deep transverses or floors. These
additional secondary stresses, designated by f L*2 , may be approximated by simple beam theory.
The secondary stresses, fL2, fT2 or f L*2 , may be taken as uniformly distributed in the flange plating
and face plates.
1.5.3 Tertiary
Tertiary stresses are those resulting from local bendings of the plate panels between stiffeners. The
tertiary stresses, designated by fL3 or fT3, can be calculated using classic plate theory. These
stresses are referred to as point stresses at the surface of the plate.

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 5 Total Strength Assessment 5C-5-5

1.7 Structural Details (1998)

The strength criteria specified in 5C-5-4/3 through 5C-5-4/25 and Section 5C-5-6 are based on assumptions
that all structural joints and welded details are properly designed and fabricated and are compatible with
the anticipated working stress levels at the locations considered. It is critical to closely examine the loading
patterns, stress concentrations and potential failure modes of all structural joints and details during the
design of highly stressed regions. In this exercise, failure criteria specified in 5C-5-5/3, 5C-5-5/5 and 5C-5-5/7
may be used to assess the adequacy of structural details.
To enhance the structural integrity and to prevent possible cracks at hatch corners, due consideration is to
be given to the shapes of cut-outs and to the heavy insert plates as shown in 5C-5-4/Figure 2, of material
with impact properties corresponding to the material class required for stringer plate in strength deck in
3-1-2/Tables 1 and 2.

3 Yielding Criteria

3.1 General
To prevent structural failure due to material yielding, the calculated stresses in the hull structure are to be
within the limits given below for all of the combined load cases specified in 5C-5-3/9.3.

3.3 Structural Members and Elements

For all structural members and elements, such as longitudinals/stiffeners, web plates and flanges, the combined
effects of all of the calculated stress components are to satisfy the following limit:
fi ≤ Sm fy N/cm2 (kgf/cm2, lbf/in2)
where
fi = stress intensity

= ( f L2 + f T2 − fL fT + 3 f LT
2 1/2
)
fL = calculated total in-plane stress in the longitudinal direction including the primary,
secondary and local load effects

= fL1 + fL2 + f L*2 + fLW N/cm2 (kgf/cm2, lbf/in2)

fL1 = direct stress due to primary (hull girder) bending, in N/cm2 (kgf/cm2, lbf/in2)
fL2 = direct stress due to secondary bending between bulkheads in the longitudinal
direction N/cm2 (kgf/cm2, lbf/in2)
f L*2 = direct stress due to local bending of longitudinals or stiffeners between transverses in
the longitudinal direction, in N/cm2 (kgf/cm2, lbf/in2)
fLW = warping stresses in the longitudinal direction, in N/cm2 (kgf/cm2, lbf/in2)
fT = calculated total direct stress in the transverse/vertical direction, including the
secondary and local load effects

= fT2 + f T*2 N/cm2 (kgf/cm2, lbf/in2)

fLT = calculated total in-plane shear stress, in N/cm2 (kgf/cm2, lbf/in2)
fT2 = direct stress due to secondary bending between bulkheads in the transverse/vertical
direction, in N/cm2 (kgf/cm2, lbf/in2)
f T*2 = direct stress due to local bending of stiffeners in the transverse/vertical direction, in
N/cm2 (kgf/cm2, lbf/in2)
fy = specified minimum yield point, in N/cm2 (kgf/cm2, lbf/in2)
Sm = strength reduction factor, as defined in 5C-5-4/11.3.1

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 5 Total Strength Assessment 5C-5-5

For this purpose, f L*2 and f T*2 in the flanges of longitudinals and stiffeners, at the ends of their spans, may
be obtained from the following equation:

f L*2 = 0.071spl2/SML N/cm2 (kgf/cm2, lbf/in2)

f T*2 = 0.071spl2/SMT N/cm2 (kgf/cm2, lbf/in2)

where
s = spacing of longitudinals (stiffeners), in cm (in.)
l = unsupported span of the longitudinal (stiffener), in cm (in.)
p = net pressure load, in N/cm2 (kgf/cm2, lbf/in2), for the longitudinal (stiffener)
SML (SMT) = net section modulus, in cm3 (in3), of the longitudinal (stiffener)

3.5 Plating (2007)

For plating away from knuckle or cruciform connection of high stress concentrations and subject to both
in-plane and lateral loads, the combined effects of all of the calculated stress components are to satisfy the
limits specified in 5C-5-5/3.3 above with fL and fT modified as follows:
fL = fL1 + fL2 + f L*2 + fLW + fL3 N/cm2 (kgf/cm2, lbf/in2)
fT = fT2 + f T*2 + fT3 N/cm2 (kgf/cm2, lbf/in2)
where
fL3, fT3 = equivalent plate bending stresses between stiffeners in the longitudinal and transverse
directions, respectively, and may be approximated as follows:
fL3 = kL p(s/tn)2 N/cm2 (kgf/cm2, lbf/in2)
fT3 = kT p(s/tn)2 N/cm2 (kgf/cm2, lbf/in2)
kL = 0.182 or 0.266 for stiffeners in the longitudinal or transverse direction, respectively
kT = 0.266 or 0.182 for stiffeners in the longitudinal or transverse direction, respectively
p = net lateral pressures for the combined load case considered [see 5C-5-3/9.3.1(b)], in
N/cm2 (kgf/cm2, lbf/in2)
s = stiffeners spacing, in mm (in.)
tn = net plate thickness, in mm (in.)
For plating within two longitudinals or stiffeners from knuckle or cruciform connections of high stress
concentrations, the combined effects of the calculated stress components are to satisfy the following stress limit:
fi ≤ 0.80 Sm fy
where
fi = stress intensity

= (f L
2
+ f T2 − f L f T + 3 f LT
2
)
1/ 2

fL = calculated total in-plane stress in the longitudinal direction including the primary and
secondary stresses
= fL1 + fL2 + fLW N/cm2 (kgf/cm2, lbf/in2)
fT = calculated total direct stress in the transverse/vertical direction, including the secondary
stresses
= fT2 N/cm2 (kgf/cm2, lbf/in2)
In addition, the failure criteria for knuckle or cruciform connections in 5C-5-5/11 are to be complied with.
fL1, fL2, f L*2 , fLW, fT2 and f T*2 are as defined in 5C-5-5/3.3 above

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 5 Total Strength Assessment 5C-5-5

5 Buckling and Ultimate Strength Criteria (1998)

5.1 General
5.1.1 Approach
The strength criteria given here correspond to either serviceability (buckling) state limit or ultimate
state limit for structural members and panels, according to the intended functions and buckling
resistance capability of the structure. For plate panels between stiffeners of decks, shell or plane
bulkhead, buckling in the elastic range is acceptable, provided that the ultimate strength of the
structure satisfies the specified design limits. The critical buckling stresses and ultimate strength of
structural elements and members may be determined based on either well documented experimental
data or a calibrated analytical approach. When a detailed analysis is not available, the equations
given in Appendix 5C-5-A2 may be used to assess the buckling strength.
5.1.2 Buckling Control Concepts
The strength criteria, given in 5C-5-5/5.3 through 5C-5-5/5.11 below, are based on the following
assumptions and limitations with respect to buckling control in the design.
5.1.2(a) The buckling strength of longitudinals and stiffeners is generally greater than that of the
plate panels being supported by the stiffeners.
5.1.2(b) All of the longitudinals and stiffeners are designed to have moments of inertia with the
associated effective plating not less than io given in 5C-5-A2/11.1.
5.1.2(c) The main supporting members, including transverses, girders and floors with the effective
associated plating, are to have the moment of inertia not less than is given in 5C-5-A2/11.5.
5.1.2(d) Face plates and flanges of girders, longitudinals and stiffeners are proportioned such that
local instability is prevented. (5C-5-A2/11.7).
5.1.2(e) Webs of longitudinals and stiffeners are proportioned such that local instability is prevented.
(5C-5-A2/11.9).
5.1.2(f) Webs of girders, floors and transverses are designed with proper proportions and stiffening
systems to prevent local instability. Critical buckling stresses of the webs may be calculated from
equations given in 5C-5-A2/3.
For structures which do not satisfy these assumptions, a detailed analysis of buckling strength
using an acceptable method is to be submitted for review.

5.3 Plate Panels

5.3.1 Buckling State Limit (1 July 2005)
The buckling state limit for plate panels between stiffeners is defined by the following equation:
(fL /fcL)2 + (fT /fcT)2 + (fLT /fcLT)2 ≤ 1.0
where
fL = calculated total compressive stress in the longitudinal direction for the plate,
in N/cm2 (kgf/cm2, lbf/in2), induced by bending and torsion of the hull girder
and large stiffened panels between bulkheads
fT = calculated total compressive stress in the transverse/vertical direction, in
N/cm2 (kgf/cm2, lbf/in2)
fLT = calculated total shear stresses in the horizontal/vertical plane, in N/cm2
(kgf/cm2, lbf/in2)
fcL, fcT and fcLT are the critical buckling stresses corresponding to uniaxial compression in the
longitudinal, transverse/vertical direction and edge shear, respectively, in N/cm2 (kgf/cm2, lbf/in2),
and may be determined from the equations given in Appendix 5C-5-A2.
fL, fT and fLT are to be determined for the critical combined load cases specified in 5C-5-3/9.3
including the primary and secondary stresses as defined in 5C-5-5/3.3. fL and fT may be taken as
zero when they are in tension.

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Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 5 Total Strength Assessment 5C-5-5

5.3.2 Effective Width

When the buckling state limit specified in 5C-5-5/5.3.1 above is not satisfied, the effective width
bwL or bwT of the plating given below is to be used instead of the full width between longitudinals,
s, for determining the effective hull girder section modulus SMe, specified in 5C-5-5/5.13.1 and
also for verifying the ultimate strength as specified in 5C-5-5/5.3.3 below. When the buckling state
limit in 5C-5-5/5.3.1 above is satisfied, the full width between longitudinals, s, may be used as the
effective width bwL for verifying the ultimate strength of longitudinals and stiffeners specified in
5C-5-5/5.5 and for determining the effective hull girder section modulus SMe specified in
5C-5-5/5.13.1 below.
5.3.2(a) For long plate (Compression on the short edges)
bwL /s = Ce
Ce = 2.25/β − 1.25/β2 for β > 1.25

= 1.0 for β ≤ 1.25

β = (fy /E)1/2s/tn
fy = specified minimum yield point of the material, in N/cm2 (kgf/cm2, lbf/in2)
s, tn and E are as defined in 5C-5-5/5.3.1 above.
5.3.2(b) For wide plate (Compression on the long edges)
bwT /l = Ces/l + 0.115 (1 − s/l) (1+ 1/β2)2 ≤ 1.0
where
l = spacing of transverses/girders
Ce, s and l are as defined in 5C-5-5/5.3.2(a) above.

5.3.3 Ultimate Strength (1 July 2005)

The ultimate strength of a plate panel between stiffeners is to satisfy all of the following equations:
(fL /fuL)2 + (fLT /fuLT)2 ≤ Sm;
(fT /fuT)2 + (fLT /fuLT)2 ≤ Sm;

(fL /fuL)2 + (fT /fuT)2 − η(fL /fuL)(fT /fuT) + (fLT /fuLT)2 ≤ Sm

where
η = (1/2)(3 − β) ≥ 0
fL, fT and fLT are as defined in 5C-5-5/5.3.1 above.

β is as defined in 5C-5-5/5.3.2 above.

Sm is as defined in 5C-5-4/11.3.1.
fuL, fuT and fuLT are the ultimate strengths with respect to uniaxial compression and edge shear,
respectively, and may be obtained from the following equations and do not need to be taken less
than the corresponding critical buckling stresses specified in 5C-5-5/5.3.1 above:
fuL = fy bwL /s ≥ fcL, fuT = fy bwT /l ≥ fcT
for plating longitudinally stiffened
fuL = fy bwT /l ≥ fcL, fuT = fy bwL /s ≥ fcT
for plating transversely stiffened
fuLT = fcLT + 0.5 (fy − 1.73fcLT)/(1 + α + α2)1/2 ≥ fcLT

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 5 Total Strength Assessment 5C-5-5

where
α = l/s
fy, bwL, bwT, s, l, fcL, fcT and fcLT are as defined above.
When assessing the ultimate strength of plate panels between stiffeners, special attention is to be
paid to the longitudinal bulkhead plating in the regions of high hull girder shear forces, and the
bottom and inner bottom platings in the mid region of cargo holds subject to bi-axial compression.

5.5 Longitudinals and Stiffeners

5.5.1 Beam-Column Buckling State Limits and Ultimate Strength (2007)
The buckling state limit for longitudinals and stiffeners are considered as the ultimate state limit
for these members and, in combination with the effective plating, are to be determined as follows:
fa/(fca Ae /A) + m fb/fy ≤ Sm
where
fa = nominal calculated compressive stress
= P/A N/cm2 (kgf/cm2, lbf/in2)
P = total compressive load, N (kgf, lbf)
fca = critical buckling stress, as given in 5C-5-A2/5.1, in N/cm2 (kgf/cm2, lbf/in2)
A = total net sectional area, in cm2 (in2)
= As + stn
As = net sectional area of the longitudinal, excluding the associated plating, in cm2
(in2)
Ae = effective net sectional area, in cm2 (in2)
= As + bwL tn
E = Young’s modulus for steel, 2.06 × 107 N/cm2 (2.1 × 106 kgf/cm2,
30 × 106 lbf/in2)
fy = minimum specified yield point of the longitudinal or stiffener under
consideration, N/cm2 (kgf/cm2, lbf/in2)
fb = effective bending stress, N/cm2 (kgf/cm2, lbf/in2)
= M/SMe
M = maximum total bending moment induced by lateral loads
= Cm psl2/12 N-cm (kgf-cm, lbf-in)
Cm = moment adjustment coefficient and may be taken as 0.75
p = lateral pressure for the region considered, in N/cm2 (kgf/cm2, lbf/in2)
s = spacing of the longitudinals, cm (in.)
SMe = effective net section modulus of the longitudinal at flange, including the
effective plating be, in cm3 (in3).
be = effective breadth as specified in 5C-5-4/Figure 7, line b.
m = amplification factor
= 1/[1 − fa/π2E (r/l)2] ≥ 1.0
tn and bWL are as defined in 5C-5-5/5.3, in cm (in.).
Sm is as defined in 5C-5-4/11.3.1.

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 5 Total Strength Assessment 5C-5-5

r and l are as defined in 5C-5-A2/5.1.

The above ultimate state limit need not be applied to the longitudinals having a relatively rigid
support at one end provided that the bracket system at the rigid end is evaluated using a fine mesh
finite element model and the following strength requirement is complied with:
fa/(fca Ae /A) ≤ Sm

5.5.2 Torsional-Flexural Buckling State Limit (2002)

In general, the torsional-flexural buckling state limit of longitudinals and stiffeners is to satisfy the
ultimate state limits given below:
fa /( fct Ae /A) ≤ Sm
where
fa = nominal calculated compressive stress, in N/cm2 (kgf/cm2, lbf/in2), as
defined in 5C-5-5/5.5.1 above
fct = critical torsional-flexural buckling stress, in N/cm2 (kgf/cm2, lbf/in2), and
may be determined by equations given in 5C-5-A2/5.5.
Ae and A are as defined in 5C-5-5/5.5.1 above and Sm is as defined in 5C-5-4/11.3.1.

5.7 Stiffened Panels

5.7.1 Large Stiffened Panels Between Bulkheads
For a vessel under the assumptions made in 5C-5-5/5.1 above with respect to the buckling control
concepts, the large stiffened panels of the double bottom and double side structures between
transverse bulkheads should automatically satisfy the design limits, provided each individual plate
panel and longitudinally and uniaxially stiffened panel satisfy the specified ultimate state limits.
Assessments of the buckling state limits are to be performed for large stiffened panels of the single
side shell and plane transverse bulkheads. In this regard, the buckling strength is to satisfy the
following condition for uniaxially or orthogonally stiffened panels.
(fL /fcL)2 + (fT /fcT)2 ≤ Sm
where
fL , fT = the calculated average compressive stresses in the longitudinal and
transverse/vertical directions, respectively, in N/cm2 (kgf/cm2, lbf/in2).
fcL, fcT = the critical buckling stresses for uniaxial compression in the longitudinal and
transverse direction, respectively, and may be determined in accordance with
5C-5-A2/7, in N/cm2 (kgf/cm2, lbf/in2)
Sm = strength reduction factor, as defined in 5C-5-4/11.3.1

5.7.2 Uniaxially Stiffened Panels between Transverses and Girders

The buckling strength of uniaxially stiffened panels between deep transverses and girders is also
to be examined in accordance with the specifications given in 5C-5-5/5.7.1 above.

5.9 Deep Girders and Webs

5.9.1 Buckling Criteria (2007)
In general, the stiffness of the web stiffeners along the depth of the web plating is to be in compliance
with the requirements 5C-5-A2/11.3. Web stiffeners which are oriented parallel to and near the face
plate and thus subject to axial compression are also to satisfy the limits specified in 5C-5-5/5.5,
considering the combined effect of the compressive and bending stresses in the web. In this case, the
unsupported span of these parallel stiffeners may be taken between tripping brackets, as applicable.
The buckling strength of the web plate between stiffeners and flange/face plate is to satisfy the
limits specified below:

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 5 Total Strength Assessment 5C-5-5

5.9.1(a) For Web Plate

(fL /fcL)2 + (fb /fcb)2 + (fLT /fcLT)2 ≤ Sm
where
fL = calculated uniform compressive stress along the length of the girder, in
N/cm2 (kgf/cm2, lbf/in2).
fb = calculated ideal bending stress, in N/cm2 (kgf/cm2, lbf/in2).
fLT = calculated total shear stress, including hull girder and local loads where
applicable, in N/cm2 (kgf/cm2, lbf/in2).
fL, fb and fLT are to be calculated for the panel in question under the combined load cases specified
in 5C-5-3/9.3 and these stresses may be calculated from the relative displacements of four corner
nodes. This method is useful when the meshing within the panel is irregular. However, care should
be taken when one corner of the panel is located in an area of high stress concentration. The
calculated stresses from the above mentioned method tend to be on the conservative side. If the
mesh is sufficiently refined, the plate panel stresses may be calculated from the displacements
slightly away from the corner point in the said high stress concentration. For a regularly meshed
plate panel, fL, fb and fLT may be also directly calculated from the components stresses for the
elements in the panel. fcL, fcb and fcLT are critical buckling stresses with respect to uniform
compression, ideal bending and shear, respectively, and may be determined in accordance with
Appendix 5C-5-A2.
Sm is as defined in 5C-5-4/11.3.1.
In the determination of fcL and fcLT, the effects of openings are to be appropriately considered.
A practical method of determining the buckling strength is the well established eigenvalue analysis
method with suitable edge constrains. If the predicted buckling stresses exceed the proportional
linear elastic limit, which may be taken as 0.6 × fy for steel, plasticity correction is to be made.
5.9.1(b) For Face Plate and Flange. The breadth to thickness ratio of face plate and flange is to
satisfy the limits given in 5C-5-A2/11.7.
5.9.1(c) For Large Brackets and Sloping Webs. The buckling strength is to satisfy the limits
specified in 5C-5-5/5.9.1(a) above for web plate.
5.9.2 Tripping
Tripping brackets are to be provided in accordance with 5C-5-A2/9.5.

5.11 Longitudinal Deck Girders, Cross Deck Box Beams and Vertical Webs
The buckling and ultimate state limits for the longitudinal deck girders inboard of lines of hatch openings,
the cross deck box beams where no longitudinal deck girder is installed, and the vertical webs of mid-hold
strength bulkhead where no horizontal girder is installed are to be determined as follows:
fa /fua + fb/fy ≤ Sm
where
fa = nominal calculated compressive stress = P/A, in N/cm2 (kgf/cm2, lbf/in2)
P = total compressive load, in N (kgf, lbf)
fua = critical buckling stress, fca as given in 5C-5-A2/5.1 or fcT as given 5C-5-A2/5.5,
whichever is lesser, in N/cm (kgf/cm2, lbf/in2)
A = total net sectional area, in cm2 (in2)
fb = effective bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= M/SM

718 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 5 Total Strength Assessment 5C-5-5

M = maximum bending moment, as given in 5C-5-5/5.5.1. (See also 5C-5-A2/5.3.2.)

SM = effective section modulus, in cm3 (in3)
Sm and fy are as defined in 5C-5-4/11.3.1.

5.13 Hull Girder Ultimate Strength

In addition to the strength requirements specified in 5C-5-4/3.1, the ultimate strength of the hull girder is to
be assessed for the combined load cases given in 5C-5-3/9.3 and the specifications given in 5C-5-5/5.13.1
and 5C-5-5/5.13.2 below.
5.13.1 Maximum Longitudinal Bending Stresses
The maximum longitudinal bending stresses in the deck and bottom plating are not to be greater
than that given in 5C-5-5/5.13.1(a), below.
5.13.1(a) (1 July 2005)
fL ≤ S m f y
where
fL = total direct stress in the longitudinal direction, in N/cm2 (kgf/cm2, lbf/in2)
= fb1 + fb2
fb1 = effective longitudinal bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= Mt /SMe
Mt = Ms + ku kc Mw in N-cm (kgf-cm, lbf-in)
ku = 1.15
kc = 1.0
SMe = the effective section modulus, as obtained from 5C-5-5/5.13.1(b) below, in
cm3 (in3).
Sm = the strength reduction factor, as defined in 5C-5-4/11.3.1
fy = minimum specified yield point of the material, in N/cm2 (kgf/cm2, lbf/in2)
fb2 = secondary bending stress of large stiffened panel between longitudinal
bulkheads and transverse bulkheads, in N/cm2 (kgf/cm2, lbf/in2)
5.13.1(b) Calculation of SMe (2010). For assessing the hull girder ultimate strength, the effective
section modulus is to be calculated, accounting for the buckling of plate panels. For vessels
constructed of higher strength material, the effective width of the side, bottom shell and
longitudinal bulkhead plating is to be used instead of the full width between longitudinals. The
effective width, bwL, is given in 5C-5-5/5.3.2 above.
Alternatively, the hull girder ultimate strength can be determined in accordance with Appendix
5C-5-A4 “Guide for Hull Girder Ultimate Strength Assessment of Container Carriers”. The wave
induced bending moment used in the evaluation is calculated with kw = 1.84 – 0.56Cb in 5C-5-3/5.1.

5.13.2 Buckling and Ultimate Strength of Large Stiffened Panels

Under the combined effects of the normal stresses, fL and fT, and shear stresses, fLT, the buckling
strength and ultimate strength of the stiffened panel are to satisfy the requirements specified in
5C-5-5/5.7.

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 5 Total Strength Assessment 5C-5-5

5.13.3 Hull Girder Shear Strength (1 July 2005)

The hull girder shear stress of the side shell and longitudinal bulkhead is not to be greater than that
given below.
fs ≤ Sm fuLT
where
fs = hull girder shear stress, in N/cm2 (kgf/cm2, lbf/in2), may be calculated for Ft
from the equations in 5C-5-4/5.3 and 5C-5-4/5.5, using the net thickness of
the side shell and longitudinal bulkhead.
Ft = Fs + kc ku Fw , ku = 1.15, kc = 1.0, kN (tf, Ltf)
Sm = strength reduction factor, as defined in 5C-5-4/11.3.1
fuLT = ultimate shear strength of panel, as defined in 5C-5-5/5.3.3

7 Fatigue Life (1998)

7.1 General
The fatigue strength of welded joints and details in highly stressed areas is to be analyzed, especially where
higher strength steel is used. Special attention is to be given to structural notches, cut-outs and bracket toes
and also to abrupt changes of structural sections. A simplified assessment of the fatigue strength of
structural details may be accepted when carried out in accordance with Appendix 5C-5-A1.
The following subparagraphs are intended to emphasize the main points and to outline procedures where
refined spectral analysis techniques are used to establish fatigue strength.
7.1.1 Workmanship
Most fatigue data available were experimentally developed under controlled laboratory conditions.
Therefore, consideration is to be given to the workmanship expected during the construction.
7.1.2 Fatigue Data
In the selection of appropriate S-N curves and the associated stress concentration factors, attention
is to be paid to the background of all design data and its validity for the details being considered.
In this regard, recognized design data, such as those by AWS (American Welding Society), API
(American Petroleum Institute), and DEn (Department of Energy), should be considered. Sample
fatigue data and their applications are shown in Appendix 5C-5-A1, “Guide for Fatigue Strength
Assessment of Container Carriers.” If other fatigue data are to be used, the background and supporting
data are to be submitted for review.
In this regard, clarification is required whether or not the stress concentration due to the weld
profile, certain structural configurations and also the heat effects are accounted for in the proposed
S-N curve. Considerations are also to be given to the additional stress concentrations.
7.1.3 Total Stress Range
For determining total stress ranges, the fluctuating stress components resulting from the load cases
specified in 5C-5-A1/7.5.2 are to be considered.
7.1.4 Design Consideration
In design, consideration is to be given to the minimization of structural notches and stress
concentrations. Areas subject to highly concentrated forces are to be properly configured and
stiffened to dissipate the concentrated loads. See also 5C-5-5/1.7.

720 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 5 Total Strength Assessment 5C-5-5

7.3 Procedures
The analysis of fatigue strength for a welded structural joint/detail may be performed in accordance with
the following procedures.
7.3.1 Step 1 – Classification for Various Critical Locations
The class designations and associated load patterns are given in 5C-5-A1/Table 1
7.3.2 Step 2 – Permissible Stress Range Approach
Where deemed appropriate, the total applied stress range of the structural details classified in Step 1
may be checked against the permissible stress ranges as shown in Appendix 5C-5-A1.
7.3.3 Step 3 – Refined Analysis
Refined analyses are to be performed as outlined in 5C-5-5/7.3.3(a) or 5C-5-5/7.3.3(b) below for
the structural details for which the total applied stress ranges obtained from Step 2 are greater than
the permissible stress ranges, or for which the fatigue characteristics are not covered by the
classified details and the associated S-N curves.
The fatigue life of the structure is generally not to be less than 20 years unless otherwise specified.
7.3.3(a) Spectral Analysis. Alternatively, a spectral analysis may be performed as outlined in
5C-5-5/7.5 below to directly calculate fatigue lives for the structural details in question.
7.3.3(b) Refined Fatigue Data. For structural details which are not covered by the detail
classifications, proposed S-N curves and the associated SCFs, when applicable, may be submitted
for consideration. In this regard, sufficient supporting data and background are also to be submitted
for review. The refined SCFs may be determined by finite element analyses.

7.5 Spectral Analysis

Where the option in 5C-5-5/7.3.3(a) is exercised, a spectral analysis is to be performed in accordance with
the following guidelines.
7.5.1 Representative Loading Patterns
Several representative loading patterns are to be considered to cover the worst scenarios anticipated
for the design service life of the vessel with respect to the hull girder local loads.
7.5.2 Environmental Representation
Instead of the design wave loads specified in Section 5C-5-3, a wave scatter diagram (such as
Walden Data) is to be employed to simulate a representative distribution of all of the wave
conditions expected for the design service life of the vessel. In general, the wave data is to cover a
time period of not less than 20 years. The probability of occurrence for each combination of significant
wave height and mean period of the representative wave scatter diagram is to be weighted based
on the transit time of the vessel at each wave environment within the anticipated shipping routes.
The representative environment (the wave scatter diagram) is not to be taken less severe than the
North Atlantic Ocean in terms of the fatigue damage.
7.5.3 Calculation of Wave Load RAOs
The wave load RAOs with respect to the wave induced bending moments, shear forces, motions,
accelerations and hydrodynamic pressures can then be predicted by ship motion calculation for a
selected representative loading condition.
7.5.4 Generation of Stress Spectrum
The stress spectrum for each critical structural detail (spot) may be generated by performing a
structural analysis, accounting for all of the wave loads separately for each individual wave group.
For this purpose, the 3D structural model and 2D models specified in Section 5C-5-3 may be used
for determining structural responses. The additional secondary and tertiary stresses are also to be
considered.
7.5.5 Cumulative Fatigue Damage and Fatigue Life
Based on the stress spectrum and the wave scatter diagram established above, the cumulative fatigue
damage and the corresponding fatigue life can be estimated by the Palmgren-Miner linear damage rule.

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Section 5 Total Strength Assessment 5C-5-5

9 Calculation of Structural Responses (1998)

9.1 Methods of Approach and Analysis Procedures (1998)

To verify the strength of the structure, the maximum stresses (load effects) in the structure are to be determined
by performing appropriate structural analyses as outlined below. Guidelines on structural idealization, load
application and structural analysis are given in ABS Guidance for Finite Element Analysis of Container
Carrier Structures.

9.3 3D Finite Element Models (1998)

A simplified three-dimensional (3D) finite element model, usually representing three cargo holds within
0.4L amidships, is required to determine the load distribution in the structure.
Two or more 3D F.E. models may be required to simulate the actual design arrangements and scantlings to
cover all critical regions for designs where the structural configuration and scantlings of the hold structure
vary significantly among the cargo spaces. A separate 3D F.E. model is recommended to represent the
forebody structures for the analysis when bottom slamming and bowflare slamming are to be considered,
as specified in 5C-5-3/11.1 and 5C-5-3/11.3.

9.5 2D Finite Element Models (1998)

Two-dimensional fine mesh finite element models are required to determine the stress distribution in major
supporting structures, particularly at intersections of two or more major structural members, for longitudinal
and transverse/horizontal structural sections.

9.7 Refined 3D Local Structural Models (1998)

A 3D fine mesh model is to be used to examine stress concentrations, such as at hatch corners, connections
of longitudinal hatch girders to cross deck box beams and at intersections of transverse bulkheads with
longitudinal wing box girders.

9.9 Load Cases (1998)

When performing structural analyses, the ten combined load cases specified in 5C-5-3/9.1 are to be considered.
In general, the structural responses for the still-water conditions are to be calculated separately to establish
reference points for assessing the wave induced responses. Additional load cases may be required for
special loading patterns and unusual design functions, such as impact loads as specified in 5C-5-3/11.
Additional load cases may also be required for hull structures beyond the region of 0.4L amidships.

11 Critical Areas (2007)

The fatigue strength of the critical areas shown in 5C-5-5/Figure 1 is to be verified by fine mesh finite
element models built in accordance with Appendix 5C-5-A1.
The mesh size in way of high stress concentration is to be of plate thickness dimension (t), and not to be
greater than 50 mm × 50 mm. The element stress intensity of half plate thickness dimension (t/2) away
from the weld toe is to satisfy the following stress limit:
fi ≤ fu
where
fi = stress intensity

= (f L
2
+ f T2 − f L f T + 3 f LT
2
)
1/ 2

fL = calculated total in-plane element stress in the longitudinal direction

fT = calculated total in-plane element stress in the transverse/vertical direction
fLT = calculated total in-plane element shear stress
fu = the minimum tensile strength of the material

722 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 5 Total Strength Assessment 5C-5-5

FIGURE 1
Critical Areas (2007)

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 723
PART Section 6: Hull Structure Beyond 0.4L Amidships

5C
CHAPTER 5 Vessels Intended to Carry Containers (130 meters
(427 feet) to 450 meters (1476 feet) in Length)

SECTION 6 Hull Structure Beyond 0.4L Amidships

1 General Requirements

1.1 General
The structural configurations, stiffening systems and design scantlings of the hull structures located beyond
0.4L amidships, including the forebody, aftbody and machinery spaces, are to be in compliance with the Rules.
The nominal design corrosion values for structural members within cargo spaces are to be in compliance
with 5C-5-2/Table 1. For structural members located in other than cargo spaces, the corrosion values may
be taken as below in establishing design scantlings.
1. 1.5 mm (0.06 in.) for side shell plating
2. 1.0 mm (0.04 in.) for bottom shell plating
3. 1.5 mm (0.06 in.) in the tank spaces and double bottom
4. 1.0 mm (0.04 in.) in dry spaces and decks

1.3 Structure within Cargo Spaces (2002)

The scantlings of longitudinal structural members in way of cargo spaces beyond the 0.4L amidships may
be gradually reduced toward 0.1L from the ends, provided that the hull girder section modulus is in
compliance with the requirements given in 5C-5-4/3.1.1 and that the strength of the structure satisfies the
requirements specified in 5C-5-6/3 through 5C-5-6/21 and 5C-5-6/25 and the material yielding, buckling
and ultimate strength criteria specified in 5C-5-5/3 and 5C-5-5/5.
In addition, consideration is to be given to the effects of the impact loads, as specified in 5C-5-3/5.3 and
5C-5-3/11, with respect to the local structures, as outlined in 5C-5-6/23.
The scantlings of transverse bulkheads in way of cargo spaces beyond 0.4L amidships may be determined
in accordance with 5C-5-4/23.

3 Bottom Shell Plating and Stiffeners in Forebody

3.1 Bottom Shell Plating

The net thickness of the bottom shell plating is to be not less than t, obtained from the following equations
and is not to extend for more than 0.1L at the fore end. Between the midship 0.4L and 0.1L from the FP,
the thickness of the plating may be gradually tapered.
t = 0.03(L + 29) + 0.009s mm for L ≤ 305 m

= (10.70 + 0.009s) D / 35 mm for L > 305 m

t = 0.00036(L + 95) + 0.009s in. for L ≤ 1000 ft

= (0.421 + 0.009s) D / 114.8 in. for L > 1000 ft

724 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

where
s = fore peak frame spacing, in mm (in.)
L = length of vessel, as defined in 3-1-1/3.1, in m (ft)
D = molded depth, in m (ft), as defined in 3-1-1/7.1 or 35 m (114.8 ft), whichever is greater
The net bottom shell plating thickness, where constructed of higher-strength material, is to be not less than
obtained from the following equation:

thts = [tms − C] [(Q + 2 Q )/3] + C

where
thts = net thickness of higher-strength material, in mm (in.)
tms = net thickness, in mm (in.), of ordinary-strength steel, as required above.
Q = material conversion factor, as specified in 5C-5-4/5
C = 3.3 (0.13)
In determining the thickness of bottom shell plating constructed of higher-strength material and transversely
framed, the critical buckling stress of the plating is to be checked in accordance with Appendix 5C-5-A2.
Shell plating is also not to be less in thickness than required by 5C-5-6/19 for deep tanks.

3.3 Bottom Longitudinals and Transverse Frames

Frames are not to have less strength than is required in 5C-5-6/3.3.1 and 5C-5-6/3.3.2 below, respectively.
In way of deep tanks, they are not to have less strength than is required in 5C-5-6/19 for stiffeners on deep-
tank bulkheads.
3.3.1 Bottom Longitudinals
The net section modulus of the bottom longitudinal required by 5C-5-4/11.5 for 0.4L amidships
may be gradually reduced to the values required by 5C-5-6/5.11.1 toward 0.1L from the FP,
provided that the hull girder section modulus at the location under consideration is in compliance
with the requirements given in 5C-5-4/3.1.1. In no case is the net section modulus of each bottom
shell longitudinal in association with the effective plating to be less than that obtained from the
equations in 5C-5-6/5.11.1.
3.3.2 Bottom Transverse Frames
The bottom transverse frame, in association with the effective plating to which it is attached, is to
be not less than that obtained from the following equation:
SM = kc1c2hsl2Q cm3 (in3)
where
k = 7.8 (0.0041)
s = spacing of the frames, in m (ft)
c1 = 1.0
c2 = 0.85
h = the vertical distance, in m (ft), from the middle of l to the load line, or two-
thirds of the distance to the bulkhead deck or freeboard deck, whichever is
greater.
l = span of frames between effective supports, in m (ft), as shown in
5C-5-4/Figure 6.
Q = material conversion factor, as specified in 5C-5-4/5.
The effective breadth of plating, be, is as defined in 5C-5-4/11.5.

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Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

5 Side Shell Plating and Stiffeners in Forebody

5.1 Side Shell Plating

The net thickness of the side shell plating is to be not less than t, obtained from the following equations
and is not to extend for more than 0.1L at the fore end. Between the midship 0.4L and 0.1L from the FP,
the thickness of the plating may be gradually tapered.
t = 0.029(L + 29) + 0.009s mm for L ≤ 305 m

= (10.20 + 0.009s) D / 35 mm for L > 305 m

t = 0.00034(L + 95) + 0.009s in. for L ≤ 1000 ft

= (0.402 + 0.009s) D / 114.8 in. for L > 1000 ft

where
s = fore peak frame spacing, in mm (in.)
L = length of vessel, as defined in 3-1-1/3.1, in m (ft)
D = molded depth, in m (ft), as defined in 3-1-1/7.1 or 35 m (114.8 ft), whichever is greater
The net side shell plating thickness, where constructed of higher-strength material, is to be not less than
obtained from the following equation:

thts = [tms – C][(Q + 2 Q )/3] + C

where
thts = net thickness of higher-strength material, in mm (in.)
tms = net thickness, in mm (in.), of ordinary-strength steel, as required above
Q = material conversion factor, as specified in 5C-5-4/5
C = 2.8 (0.11)
In determining the thickness of side shell plating constructed of higher-strength material and transversely
framed, the critical buckling stress of the plating is to be checked in accordance with Appendix 5C-5-A2.
Shell plating is also not to be less in thickness than required by 5C-5-6/19 for deep tanks.
Also, see 5C-5-6/5.9 for shell plating below the load water line for 0.16L from the FP.

5.3 Forecastle Side Shell Plating

The net thickness, t, of the forecastle side shell plating is to be not less than that obtained from the following
equation:
t = 0.0315(L + 154) + 0.006(s − S) mm
t = 0.00038(L + 505) + 0.006(s − S) in.
where
s = frame spacing, in mm (in.)
S = standard frame spacing
= 2.08L + 438 mm for L ≤ 270 m
= 1000 mm for L > 270 m
= 610 mm in way of the fore peak
S = 0.025L + 17.25 in. for L ≤ 886 ft
= 39.4 in. for L > 886 ft
= 24 in. in way of the fore peak

726 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

L = length of vessel, as defined in 3-1-1/3.1, in m (ft), but need not be taken more than
305 m (1000 ft.)
Where constructed of higher-strength material, the plating thickness is to be not less than that obtained
from the following equation:

thts = [tms − C][(Q + 2 Q )/3] + C

where
thts = net thickness of higher-strength material, in mm (in.)
tms = net thickness, in mm (in.), of ordinary-strength steel, as required above
Q = material conversion factor, as specified in 5C-5-4/5
C = 2.8 (0.11)

5.5 Stem Plating

The net thickness of plate stems at the design load waterline, where used, is not to be less than that
required by the following equations:
t = L/12 mm L ≤ 246 m
t = 20.5 mm L > 246 m
t = L/1000 in. L ≤ 807 ft
t = 0.807 in. L > 807 ft
Above and below the design load waterline, the thickness may be tapered to the thickness required in
5C-5-6/5.1 at the freeboard deck and to the thickness of the flat-plate keel at the forefoot, respectively.

5.7 Bow Thruster Tunnel

The net thickness of the tunnel plating is to be not less than required in 5C-5-6/5.1 above, where s is to be
taken as the standard frame spacing S given by the equation in 5C-5-6/5.3, nor is the thickness to be less
than that obtained from the following equation:
t = 0.008d + 1.8 mm
t = 0.008d + 0.07 in.
d = inside diameter of the tunnel, in mm (in.), but is to be taken not less than 968 mm (38 in.)
Where the outboard ends of the tunnel are provided with bars or grids, the bars or grids are to be effectively
secured.

5.9 Immersed Bow Plating (1 July 2005)

The net thickness of the plating below the load waterline for 0.16L from the FP is to be not less than t,
given by the following equations, but need not be greater than the thickness of the side shell plating amidships.
t = 0.045(L + 20) + 0.009s mm for L ≤ 305 m
= 0.00054(L + 65.6) + 0.009s in. for L ≤ 1000 ft

t = (14.75 + 0.009s) D / 35 mm for L > 305 m

= (0.58 + 0.009s) D / 114.8 in. for L > 1000 ft

where
s = fore peak frame spacing, in mm (in.)
L = length of vessel, as defined in 3-1-1/3, in m (ft)
D = molded depth, in m (ft), as defined in 3-1-1/7 or 35 m (114.8 ft), whichever is greater

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

The net plating thickness, where constructed of higher-strength material, is to be not less than obtained
from the following equation:

thts = [tms − C][(Q + 2 Q )/3] + C

where
thts = net thickness of higher-strength material, in mm (in.)
tms = net thickness, in mm (in.), of ordinary-strength steel, as required above.
Q = material conversion factor, as specified in 5C-5-4/5
C = 2.8 (0.11)

5.11 Side Longitudinals and Transverse Frames

Frames are not to have less strength than is required in 5C-5-6/17.3 for bulkhead stiffeners in the same
location in conjunction with heads to the bulkhead deck. In way of deep tanks, they are not to have less
strength than is required in 5C-5-6/19.3 for stiffeners on deep-tank bulkheads. Framing sections are to have
sufficient thickness and depth in relation to the spans between supports. See also 3-1-2/13.5.
5.11.1 Side Longitudinals
The net section modulus of each side longitudinal, in association with the effective plating to
which it is attached, is to be not less than that obtained from the following equation:
SM = k c1c2 hsl2Q cm3 (in3)
where
k = 7.8 (0.0041)
s = spacing of side longitudinals, in m (ft)
c1 = 0.95
c2 = 0.85
h = above 0.5D from the keel, the vertical distance, in m (ft), from the longitudinal
frame to the bulkhead deck but is not to be taken as less than 2.13 m (7.0 ft)
= at and below 0.5D from the keel, 0.75 times the vertical distance, in m (ft),
from the longitudinal frame to the bulkhead deck, but is not less than 0.5D
D = depth of vessel, in m (ft), as defined in 3-1-1/7
l = span of longitudinals between effective supports, in m (ft), as shown in
5C-5-4/Figure 6.
Q = material conversion factor, as specified in 5C-5-4/5.
The effective breadth of plating, be, is as defined in 5C-5-4/11.5.
The net section modulus of each longitudinal tween-deck frame forward of 0.125L from the stem
is also to be not less than required by 5C-5-6/5.11.3 below, in the same location taking l as the
unsupported span along the frame length.
5.11.2 Fore-end Transverse Frames Forward of 0.3L to 0.125L from FP
The net section modulus SM of each transverse frame, in association with the effective plating to
which it is attached, is to be not less than obtained from the following equation:
SM = sc2l2(h + bh1/33)(7 + 45/l3)Q cm3

= sc2l2(h + bh1/100)(0.0037 + 0.84/l3)Q in3

728 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

where
s = spacing of side frames, in m (ft)
c2 = 0.85
l = actual girth length along the frame, as shown in 5C-5-6/Figure 1.
Where frames are supported by a system of web frames and side stringers of
the size and arrangements obtained from Section 3-2-6, l may be taken as the
distance from the toe of the bracket to the lowest stringer plus 0.15 m (0.5 ft).
The value of l for use with the equation is not be less than 2.10 m (7 ft).
h = vertical distance, in m (ft), from the middle of l to the load line or 0.4l,
whichever is the greater.
b = horizontal distance, in m (ft), from the outside of the frames to the first row
of deck supports, as shown in 5C-5-6/Figure 1
h1 = vertical distance, in m (ft), from the deck at the top of the frame to the bulkhead
or freeboard deck plus the height of all cargo tween-deck spaces, or plus
2.44 m (8 ft). if that is greater. Where the cargo load differs from 715 kgf/m3
(45 lbf/ft3) multiplied by the tween-deck height in m (ft), the height of that
tween-deck is to be proportionately adjusted in calculating h1.
Q = material conversion factor, as specified in 5C-5-4/5
The effective breadth of plating, be, is as defined in 5C-5-4/11.5.

5.11.3 Transverse Tween-deck Frames

The net section modulus SM of each transverse tween-deck frame, in association with the effective
plating, is to be not less than that obtained from the following equation:
SM = (7 + 45/l3)sc2l2KQ cm3

= (0.0037 + 0.84/l3)sc2l2KQ in3

where
s = spacing of side frames, in m (ft)
c2 = 0.85

l = tween deck height or unsupported span along the frame length, as shown in
5C-5-6/Figure 1, whichever is greater, in m (ft)
K = factor appropriate to the length of vessel and type of tween decks, as shown
in 5C-5-6/Figure 1, defined as follows:
For L in m:
KA = 0.022L − 0.47
KB = 0.034L − 0.56
KC = 0.036L − 0.09 for L ≤ 180 m
= 0.031L + 0.83 for L > 180 m
KD = 0.029L + 1.78
For L in ft:
KA = 0.022L − 1.54
KB = 0.034L − 1.84

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

KC = 0.036L − 0.29 for L ≤ 590 ft

= 0.031L + 2.8 for L > 590 ft
KD = 0.029L + 5.84
L = length of vessel, as defined in 3-1-1/3.1, in m (ft), but need not be taken as
greater than 305 m (1000 ft)
Q = material conversion factor, as specified in 5C-5-4/5.
For tween-deck frames above the bulkhead deck forward of 0.125L from the FP, K is to be based
on KB.
The effective breadth of plating, be, is as defined in 5C-5-4/11.5.

FIGURE 1
Transverse Frames

MINIMUM
2.44 m h1 KA
BULKHEAD DECK

KB

0.15 m
h
(NO STRINGER) STRINGER
(3-2-5/3.11)
l
l

0.5 l
INNER
BOTTOM

730 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

7 Side Transverses and Stringers in Forebody

7.1 Transverse Web Frames

The net section modulus of each web frame, in association with the effective plating to which it is attached,
is to be not less than that obtained from the following equation:
SM = kc1c2sl2 (h + bh1/45K)Q cm3

= kc1c2sl2 (h + bh1/150K)Q in3

where
k = 4.74 (0.0025)
c1 = 1.5
c2 = 0.95
s = spacing of the web frames, in m (ft)
l = span, in m (ft), measured from the line of the inner bottom (extended to the side of
the vessel) to the deck at the top of the web frames. Where effective brackets are
fitted, the length l may be modified as shown in 5C-5-4/Figure 9.
h = vertical distance, in m (ft), from the middle of l to the load line. h ≥ 0.5l
h1 = vertical distance, in m (ft), from the deck at the top of the frame to the bulkhead or
freeboard deck plus the height of all cargo tween-deck spaces, or plus 2.44 m (8 ft). if
that is greater. Where the cargo load differs from 715 kgf/m3 (45 lbf/ft3) multiplied by
the tween-deck height, in m (ft), the height of that tween-deck is to be proportionately
adjusted in calculating h1
b = horizontal distance in, m (ft), from the outside of the frame to the first row of deck
supports, as shown in 5C-5-6/Figure 2.
K = 1.0, where the deck is longitudinally framed and a deck transverse is fitted in way of
each web frame
= number of transverse frame spaces between web frames where the deck is
transversely framed
Q = material conversion factor, as specified in 5C-5-4/5.
The depth and net thickness of the web are not to be less than dw and tw, respectively, as defined below:

dw = 125l mm

= 1.5l in.
tw = dw /100 + a mm (in.)
need not be greater than 13.0 mm (0.51 in.)
l is as defined above.
Web frames in way of deep-tank are to comply with 5C-5-6/19.5.
a = 2.5 (0.1)

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 731
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

7.3 Stringers
The net section modulus of each side stringer, in association with the effective plating to which it is attached,
is to be not less than that obtained from the following equation:
SM = kc1c2hsl2Q cm3 (in3)
where
k = 4.74 (0.0025)
c1 = 1.5
c2 = 0.95
Q = material conversion factor, as specified in 5C-5-4/5
h = vertical distance, in m (ft), from the middle of s to the load line, or to two-thirds of
the distance from the keel to the bulkhead deck, or 1.8 m (6 ft), whichever is greatest
s = sum of the half lengths, in m (ft), (on each side of the stringer) of the frames
supported
l = span, in m (ft), between web frames, or between web frame and bulkhead; where
brackets are fitted, the length l may be modified as shown in 5C-5-4/Figure 9
The depth and net thickness of the stringer are not to be less than dw and tw, respectively, as defined below:
dw = 125l + 0.25ds mm
= 1.5l + 0.25ds in.
but need not exceed depth of the web frames to which they are attached
tw = 0.014L + 6.2 mm for L ≤ 200 m
= 0.007L + 7.6 mm for L > 200 m
tw = 0.00017L + 0.244 in. for L ≤ 656 ft
= 0.00008L + 0.3 in. for L > 656 ft
dS is the depth of the slot, in mm (in.), for the frames and l is as defined above. In general, the depth of the
stringer is not to be less than three (3) times the depth of the slots or the slots are to be fitted with filler plates.
L = length of vessel, as defined in 3-1-1/3.1, in m (ft)
Stringers in way of deep-tank are also to comply with 5C-5-6/19.5.

7.5 Fore Peak-stringer

The peak stringer net plate thickness t and breadth b are not to be less than that obtained from the following
equations, respectively:
t = 0.014L + 5.7 mm for L ≤ 200 m
= 0.007L + 7.1 mm for L > 200 m
t = 0.00017L + 0.224 in. for L ≤ 656 ft
= 0.00008L + 0.28 in. for L > 656 ft
b = 2.22L + 600 mm
= 0.027L + 23.5 in.
where
L = length of vessel, as defined 3-1-1/3.1 in m (ft)
Where beams or struts are not fitted on every frame, the edge of the stringer is to be adequately stiffened
by a flange or face bar.

732 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

FIGURE 2
Web Frames

MINIMUM
2.44 m h1

BULKHEAD DECK

0.5 l
INNER
BOTTOM

9 Deck Structures

9.1 Strength Deck Plating Outside Line of Openings

The net thickness of the strength deck plating is to be not less than that required to meet the longitudinal
hull girder strength. The deck area contributing to the hull girder strength for amidships 0.4L is to be
gradually reduced to the end of the vessel. Where bending moment envelope curves are used to determine
the required hull girder section modulus as permitted in 5C-5-4/3.1.3, the strength deck area is to be maintained
a suitable distance beyond superstructure breaks and is to be extended into the superstructure to provide
adequate structural continuity. The net thickness is also to be not less than t specified below, except within
deckhouse where the plating may be reduced by 1 mm (0.04 in.).
9.1.1 For Longitudinally Framed Decks
t = 0.009sb + 1.4 mm for sb ≤ 760 mm (30 in.)
= 0.009sb + 0.055 in.
t = 0.006sb + 3.7 mm for sb > 760 mm (30 in.)
= 0.006sb + 0.146 in.

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

9.1.2 For Transversely Framed Decks

t = 0.01sb + 1.3 mm for sb ≤ 760 mm (30 in.)
= 0.01sb + 0.05 in.
t = 0.0066sb + 3.9 mm for sb > 760 mm (30 in.)
= 0.0066sb + 0.154 in.
where
L = length of vessel, as defined in 3-1-1/3.1, in m (ft)
sb = spacing of deck beams, in mm (in.)
The net thickness of the deck plating for longitudinally framed decks constructed of higher-strength material
is to be not less than that obtained from the following equation:
thts = (tms − C)Q + C
where
thts = net thickness of higher-strength material, in mm (in.)
tms = net thickness, in mm (in.), of ordinary-strength steel as required above
C = 3.3 (0.13)
Q = material conversion factor, as specified in 5C-5-4/5

0.92/ Q is to be used in lieu of Q for application of 5C-5-6/9.1.2 and is not to be less than 1.0.

In general, where the deck plating is constructed of higher-strength material, the critical buckling stress of
the plating is to be checked in accordance with Appendix 5C-5-A2.
The net thickness of the stringer plate is to be increased 25% in way of breaks of superstructures, but this
increase need not exceed 6.5 mm (0.25 in.).

9.3 Strength Deck Plating Within Line of Openings

Within deckhouses, the plating may be of the thickness obtained from the following equations:
t = 0.009sb − 0.2 mm for sb ≤ 685 mm (27 in.)
= 0.009sb − 0.008 in.
t = 0.0039sb + 3.3 mm for sb > 685 mm (27 in.)
= 0.0039sb + 0.13 in.
sb is as defined in 5C-5-6/9.1, above.

9.5 Forecastle Decks

The net thickness of exposed forecastle decks plating is to be not less than that obtained from 5C-5-6/9.1.2
above.

9.7 Platform Decks in Enclosed Spaces

The net thickness of the platform deck plating including lower decks is to be not less than that obtained
from the following equation:

t = ksb h + a mm (in.)
but not less than 4.0 mm (0.16 in.).

734 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

where
k = 0.00394 (0.00218)
a = 0.5 (0.02)
h = tween deck height, in m (ft)
= p/n when a design load, p, is specified
p = specified design load, in kN/m2 (kgf/m2, lbf/ft2)
n = 7.05 (715, 45)
sb is as defined in 5C-5-6/9.1.
Where the platform decks are subjected to hull girder bending, special consideration is to be given to the
structural stability of deck supporting members. Appendix 5C-5-A2 may be applied.

9.9 Watertight Flats

Watertight flats over tunnels or forming recesses or steps in bulkheads are to be of not less thickness than
required for the plating of ordinary bulkhead at the same level obtained from 5C-5-6/17.1 plus 1 mm (0.04 in.).
For decks forming tops of tanks see requirements in 5C-5-6/19.1.

9.11 Deck Longitudinals and Beams

9.11.1 Deck Longitudinals Outside the Line of Openings
The net sectional area of each deck longitudinal or beam, in association with the effective deck
plating, is to be not less than that required to meet the longitudinal hull girder strength, nor is the
associated net section modulus to be less than that obtained in 5C-5-6/9.11.2, below.
9.11.2 Beams (1 July 2005)
Each beam, in association with the plating, is to have a net section modulus SM not less than that
obtained from the following equation:
SM = kc1c2hsl2Q cm3 (in3)
where
k = 7.8 (0.0041)
s = spacing of beams, in m (ft.)
c1 = 0.585 for beams between longitudinal deck girders
for longitudinal beams of platform decks and between hatches
at all decks
= 0.90 for beams at deep-tank tops supported at one or both ends at the
shell or longitudinal bulkheads
= 0.945 for longitudinal beams of strength decks and of effective lower
decks
= 1.0 for beams at deep-tank top between longitudinal girders
c2 = 0.85
l = span of beams between effective supports, as shown in 5C-5-4/Figure 6, in m (ft)
h = height, in m (ft), as follows:
= for bulkhead recesses and tunnel flats, is the height to the bulkhead deck at
the centerline; where that height is less than 6.10 m (20 ft), the value of h is
to be taken as 0.8 times the actual height plus 1.22 m (4 ft)
= for deep-tank tops, is not to be less than two-thirds of the distance from the top
of the tank to the top of the overflow; it is not to be less than 1.3 m (4.27 ft),
the height to the load line or two-thirds of the height to the bulkhead or
freeboard deck, whichever is greatest

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Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

Elsewhere, the value of h may be taken as follows:

h = 2.9 m (9.5 ft) for bulkhead or freeboard deck having no deck below
= 2.29 m (7.5 ft) for bulkhead or freeboard deck having deck below
= 1.98 m (6.5 ft) for lower decks and platform deck
= 1.68 m (5.5 ft) for forecastle deck above bulkhead deck
Q = material conversion factor, as specified in 5C-5-4/5
The effective breadth of plating, be, is as defined in 5C-5-4/11.5.
Calculations are to be submitted to show adequate provision against buckling where higher-strength
materials are used for deck beams. Longitudinal beams are to be essentially of the same material
as the plating they support.

9.13 Deck Girders and Transverses Clear of Tanks

9.13.1 Section Modulus
Each deck girder or transverse is to have a net section modulus SM not less than obtained from the
following equation:
SM = kc1c2bhl2Q cm3 (in3)
where
k = 4.74 (0.0025)
c1 = 1.0
c2 = 0.95
b = mean breadth of the area of deck supported, in m (ft)
h = height, in m (ft), normally to be the height measured at the side of the vessel,
of the cargo space wherever stores or cargo may be carried. Where the cargo
load differs from 715 kgf/m3 (45 lbf/ft3) multiplied by the tween-deck height,
in m (ft), the height is to be proportionately adjusted.
Elsewhere, the value of h may be taken as follows:
h = 2.9 m (9.5 ft) for bulkhead or freeboard deck having no deck below
= 2.29 m (7.5 ft) for bulkhead or freeboard deck having deck below
= 1.98 m (6.5 ft) for lower decks and platform deck
= 1.68 m (5.5 ft) for forecastle deck above bulkhead deck
l = span between centers of supporting pillars, or between pillar and bulkhead,
in m (ft). Where an effective bracket is fitted at the bulkhead, the length l
may be modified as shown in 5C-5-4/Figure 9.
Q = material conversion factor, as specified in 5C-5-4/5
9.13.2 Proportions
The depth and net thickness of the girders and transverses are not to be less than dw and tw, respectively,
as defined below:
d w = kl mm (in.)
tw = dw /100 + a mm (in.)
≥ 7.5 mm (0.30 in.) for AF ≤ 38 cm2 (5.27 in2)
≥ 9.0 mm (0.35 in.) for AF ≤ 46 cm2 (8.84 in2)
≥ 11.5 mm (0.45 in.) for AF ≤ 101 cm2 (18.14 in2)
≥ 14.0 mm (0.55 in.) for AF > 165 cm2 (27.44 in2)

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Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

where
k = 58.3 (0.7)
a = 3 (0.12)
The thickness for intermediate face area may be obtained by linear interpolation.
AF is the net face area and l is as defined in 5C-5-6/9.13.1, above.

9.15 Deck Girders and Transverses in Tanks

Deck girders and transverses in tanks are to have net section modulus SM not less than obtained in the
same manner as given in 5C-5-6/9.13.1 above, except the values of c1 and h are to be as modified below.
The proportionality requirements are to be the same as given in 5C-5-6/9.13.2 of the above, except that k
for dw is not to be less than 83.3 (1.0).
c1 = 1.5

h = the greatest of the following distances, in m (ft), from the middle of l to:
• A point located two-thirds of the distance from the top of the tank to the top of
the overflow
• 1.3 m (4.27 ft) above the top of the tank
• The load line
• A point located at two-thirds of the distance to the bulkhead or freeboard deck

11 Pillars or Struts

11.1 Permissible Load

The permissible load Wa of a pillar or strut is to be obtained from the following equation which will, in all
cases, be equal to or greater than the calculated load W as determined in 5C-5-6/11.3 below.
Wa = c2(k − nl/r)Ac kN(tf, Ltf)
where
c2 = 1.05
k = 12.09 (1.232, 7.83) ordinary strength steel
= 16.11 (1.643, 10.43) HT32
= 18.12 (1.848, 11.73) HT36
l = unsupported span, in cm (ft)
The length l is to be measured from the top of the inner bottom, deck or other structure on which the
pillars or struts are based to the underside of the beam or girder supported.
r = least radius of gyration, in cm (in.)
Ac = net cross sectional area of pillar or strut, in cm2 (in2)
n = 0.0444 (0.00452, 0.345) ordinary strength steel
= 0.0747 (0.00762, 0.581) HT32
= 0.0900 (0.00918, 0.699) HT36

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

11.3 Calculated Load

The calculated load W for a pillar or strut is to be obtained from the following equation:
W = nbhs kN(tf, Ltf)
where
n = 7.04 (0.715, 0.02)
b = mean breadth of the area supported, in m (ft)
h = height above the area supported, as defined below, in m (ft)
For pillars spaced not more than two frame spaces, the height h is to be taken as the distance from the deck
supported to a point 3.80 m (12.5 ft) above the freeboard deck.
For wide-spaced pillars, the height h is to be taken as the distance from the deck supported to a point 2.44 m
(8 ft) above the freeboard deck, except in the case of such pillars immediately below the freeboard deck, in
which case, the value of h is not to be less than 2.9 m (9.5 ft) in measuring the distance from the deck
supported to the specified height above the freeboard deck.
s = mean length of the area supported, in m (ft)

11.5 Pillars under the Tops of Deep Tanks

Pillars under the tops of deep tanks are not to be less than required by the foregoing. They are to be of solid
sections and to have the net cross sectional area not less than A, as specified below:
A = c1c2 nbhs cm2 (in2)
where
c1 = 0.1035 (1.015, 0.16) ordinary strength steel
= 0.0776 (0.761, 0.12) HT32
= 0.069 (0.677, 0.107) HT36
c2 = 0.95
n = 10.5 (1.07, 0.03)
b = breadth of the area of the top of the tank supported by the pillar, in m (ft)
s = length of the area of the top of the tank supported by the pillar, in m (ft)
h = two-thirds of the distance from the top of the tank to the top of the overflow; it is not
to be less than 1.3 m (4.27 ft), the height to the load line or two-thirds of the height to
the bulkhead or freeboard deck, whichever is greatest.

13 Transition Zone

13.1 General
In the transition zone in way of the forepeak bulkhead, consideration is to be given to the proper tapering
of longitudinal members such as flats, decks, longitudinal bulkheads, horizontal ring frames or side stringers
forward into the fore peak.

738 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

15 Fore-peak Structure

15.1 General
The center girder continued from the midship is to extend as far forward as practicable. Forepeak frames
are to be efficiently connected to deep floors. The floors are to extend as high as necessary to give lateral
stiffness to the structure and are to be properly stiffened on their upper edges. Care is to be taken in
arranging the framing and floors to assure no wide areas of unsupported plating adjacent to the stem. Angle
ties are to be fitted as required across the tops of the floors and across all tiers of beams or struts to prevent
vertical or lateral movement. Breast hooks are to be arranged at regular intervals at and between the
stringers above and below the waterline.

15.3 Center Girder and Floor Plating (2001)

The net thickness of the plating is not to be less than that obtained from the following equation, but need
not exceed 12.5 mm (0.50 in.), provided the stiffeners are not spaced more than 1.22 m (4 ft).and the
buckling strength is proven adequate (see 5C-5-A2/3).
t = 0.036L + 3.2 mm
= 0.00043L + 0.126 in.
L = length of vessel, as defined in 3-1-1/3.1, in m (ft)
Floors and girders, where constructed of higher-strength material, are to be not less in thickness than as
modified by the following equation:

thts = [tms − C][(Q + 2 Q )/3] + C

where
thts = net thickness of higher-strength material, in mm (in.)
tms = net thickness, in mm (in.), of ordinary-strength steel, as required above.
Q = material conversion factor, as specified in 5C-5-4/5
C = 1.5 (0.06)

15.5 Peak Frames

The net section modulus of each peak frame is to be in compliance with 5C-5-6/5.11.
Peak frames in way of fore peak tank are to be in compliance with 5C-5-6/19.3.

17 Watertight Bulkheads

17.1 Plating (2002)

The net thickness t of the bulkhead plating forming watertight boundaries is to be not less than obtained
from the following equation:

t = sk qh /C + a mm (in.)

but not less than tmin or s/200 + c1, whichever is greater.

where
tmin = 5.5 mm (0.22 in.) within cargo spaces
5.0 mm (0.20 in.) for other than cargo spaces
c1 = 2.0 mm (0.08 in.) within cargo spaces
1.5 mm (0.06 in.) for other than cargo spaces

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

s = spacing of stiffeners, in mm (in.)

k = (3.075 α − 2.077)/(α + 0.272) (1 ≤ α ≤ 2)

= 1.0 (α > 2)
α = aspect ratio of the panel (longer edge/shorter edge)
q = 235/Y (N/mm2), 24/Y (kgf/mm2) or 34,000/Y (lbf/in2)
Y = specified minimum yield point or yield strength, in N/mm2 (kgf/mm2, lbf/in2), for the
higher-strength material or 72% of the specified minimum tensile strength, whichever
is the lesser
h = distance from the lower edge of the plate to the deepest equilibrium waterline in the
one compartment damaged condition, in m (ft)
h is to be not less than the distance to the bulkhead deck at center unless a deck lower
than the uppermost continuous deck is designated as the freeboard deck, as allowed
in 3-1-1/13.1. In such case, h is to be not less than the distance to the designated
freeboard deck at center.
C = 290 (525)
a = 1.0 (0.04) within cargo spaces
= 0.5 (0.02) for other than cargo spaces

17.3 Stiffeners (2002)

The net section modulus of each stiffener, in association with the effective plating to which it is attached, is
to be not less than that obtained from the following equation:
SM = kc1c2hsl2Q cm3 (in3)
where
k = 7.8 (0.0041)
c1 = 0.56
c2 = 0.85
s = spacing of the stiffeners, in m (ft)
h = distance, in m (ft), from the middle of l to the deepest equilibrium waterline in the
one compartment damaged condition
h is to be not less than the distance to the bulkhead deck at center unless a deck lower
than the uppermost continuous deck is designated as the freeboard deck, as allowed
in 3-1-1/13.1. In such case, h is to be not less than the distance to the designated
freeboard deck at center.
Where the distance indicated above is less than 6.10 m (20 ft), h is to be taken as 0.8
times the distance plus 1.22 m (4 ft)
l = span of stiffeners between effective supports, as shown in 5C-5-4/Figure 6, in m (ft)
Q = material conversion factor, as specified in 5C-5-4/5
The effective breadth of plating, be, is as defined in 5C-5-4/11.5.

740 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

17.5 Girders and Webs

17.5.1 Section Modulus (2002)
Each girder and web which supports bulkhead stiffeners is to have a net section modulus SM not
less than obtained from the following equation:
SM = kc1c2hsl2Q cm3 (in3)
where
k = 4.74 (0.0025)
c1 = 1.0
c2 = 0.95
h = vertical distance, in m (ft), to the deepest equilibrium waterlline in the one
compartment damaged condition from the middle of s in the case of girders,
and from the middle of l in the case of webs
h is to be not less than the distance to the bulkhead deck at center unless a deck
lower than the uppermost continuous deck is designated as the freeboard
deck, as allowed in 3-1-1/13.1. In such case, h is to be not less than the
distance to the designated freeboard deck at center.
Where the distance indicated above is less than 6.10 m (20 ft), h is to be taken
as 0.8 times the distance plus 1.22 m (4 ft).
s = sum of half lengths (on each side of girder or web) of the stiffener supported,
in m (ft)
l = span measured between the heel of end attachments, in m (ft). Where an
effective bracket is fitted at the bulkhead, the length l may be modified as
shown in 5C-5-4/Figure 9.
Q = material conversion factor, as specified in 5C-5-4/5
17.5.2 Proportions
The depth and net thickness of the girders and webs are not to be less than dw and tw, respectively,
as defined below:
dw = 83.3l + 0.25dS mm

= l + 0.25ds in.
tw = dw /100 + 2.0 mm need not exceed 10.5 mm (0.41 in.)
= dw /100 + 0.08 in.

dS is the depth of the slots for the stiffeners, in mm (in.) and l is as defined in 5C-5-6/17.5.1 above.

19 Deep Tank Bulkheads

This section applies to deep tank bulkheads where the requirements in this section exceed those of 5C-5-6/17.

19.1 Plating (1 July 2005)

The net thickness t of bulkhead plating forming tank boundaries is to be not less than obtained from the
following equation:

t = sk qh /C + a mm (in.)

but not less than 5.0 mm (0.2 in.) or s/150 + 1.0 mm (s/150 + 0.04 in.), whichever is greater.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 741
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

where
s = spacing of stiffeners, in mm (in.)

k = (3.075 α − 2.077)/(α + 0.272) (1 ≤ α ≤ 2)

= 1.0 (α > 2)
α = aspect ratio of the panel (longer edge/shorter edge)
q = 235/Y (N/mm2), 24/Y (kgf/mm2) or 34,000/Y (lbf/in2)
Y = specified minimum yield point or yield strength, in N/mm2 (kgf/mm2, lbf/in2), for the
higher-strength material or 72% of the specified minimum tensile strength, whichever
is the lesser
h = the greatest of the following distances, in m (ft), from the lower edge of the plate to:
• A point located two-thirds of the distance from the top of the tank to the top of
the overflow; where a side wing tank top extends to the underdeck passageway
(second deck), this distance need not be greater than one-third of the distance
from the second deck to the top of the overflow
• 1.3 m (4.27 ft) above the top of the tank
• The load line
• A point located at two-thirds of the distance to the bulkhead or freeboard deck
C = 254 (460)
a = 1.0 (0.04)
The tops of tanks are to have plating 0.5 mm (0.02 in.) thicker than would be required for vertical plating
at the same level.

19.3 Stiffeners (1 July 2005)

The net section modulus of each stiffener, in association with the effective plating to which it is attached, is
not to be less than that obtained from the following equation:
SM = kc1c2hsl2Q cm3 (in3)
where
k = 7.8 (0.0041)
c1 = 0.90
c2 = 0.85
s = spacing of the stiffeners, in m (ft)
h = the greatest of the following distances, in m (ft), from the middle of l to:
• A point located two-thirds of the distance from the top of the tank to the top of
the overflow; where a side wing tank top extends to the underdeck passageway
(second deck), this distance need not be greater than one-third of the distance
from the second deck to the top of the overflow
• 1.3 m (4.27 ft) above the top of the tank
• The load line
• A point located at two-thirds of the distance to the bulkhead or freeboard deck
l = span of stiffeners between effective supports, as shown in 5C-5-4/Figure 6, in m (ft)
Q = material factor, as specified in 5C-5-4/5
The effective breadth of plating, be, is as defined in 5C-5-4/11.5

742 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

19.5 Girders and Webs

19.5.1 Section Modulus
Each girder and web which support bulkhead stiffeners are to have a net section modulus SM not
less than obtained from the following equation:
SM = kc1c2shl2Q cm3 (in3)
where
k = 4.74 (0.0025)
c1 = 1.5
c2 = 0.95
h = vertical distance, in m (ft), from the middle of s in the case of girders, and from
the middle of l in the case of webs to the same height to which h for the
stiffeners is measured. See 5C-5-6/19.3, above.
s = sum of half lengths (on each side of girder or web) of the frame or stiffener
supported, in m (ft)
l = span measured between the heels of the end of the attachments, in m (ft).
Where effective brackets are fitted, the length l may be modified as shown in
5C-5-4/Figure 9.
Q = material conversion factor, as specified in 5C-5-4/5
19.5.2 Proportions
The depth and net thickness of the girders and webs are to be not less than dw and tw, respectively,
as defined below:
dw = 145l + 0.25dS mm
where no struts or ties are fitted
= 1.74l + 0.25dS in.

= 83.3l + 0.25dS mm
where struts are fitted
= l + 0.25dS in.
tw = dw/100 + 1.5 mm need not exceed 10.0 mm (0.4 in.)
= dw/100 + 0.06 in.
dS is the depth of the slots, in mm (in.), for the stiffeners and l is as defined above. In general, the
depth of the girder or web is not to be less than three (3) times the depth of the slots or the slots
are to be fitted with filler plates.

21 Collision Bulkheads

21.1 Plating (2002)

The net thickness t of the collision bulkhead plating is to be not less than obtained from the following equation:

t = sk qh /C + α mm (in.)

but not less than tmin or s/200 + c1, whichever is greater.

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

where
tmin = 5.5 mm (0.22 in.) within cargo spaces
5.0 mm (0.20 in.) for other than cargo spaces
c1 = 2.0 mm (0.08 in.) within cargo spaces
1.5 mm (0.06 in.) for other than cargo spaces
s = spacing of stiffeners, in mm (in.)

k = (3.075 α − 2.077)/(α + 0.272) (1 ≤ α ≤ 2)

= 1.0 (α > 2)
α = aspect ratio of the panel (longer edge/shorter edge)
q = 235/Y (N/mm2), 24/Y (kgf/mm2) or 34,000/Y (lbf/in2)
Y = specified minimum yield point or yield strength, in N/mm2 (kgf/mm2, lbf/in2), for the
higher-strength material or 72% of the specified minimum tensile strength, whichever
is the lesser
h = distance from the lower edge of the plate to the deepest equilibrium waterline in the
one compartment damaged condition , in m (ft)
h is to be not less than the distance to the bulkhead deck at center unless a deck lower
than the uppermost continuous deck is designated as the freeboard deck, as allowed
in 3-1-1/13.1. In such case, h is to be not less than the distance to the designated
freeboard deck at center.
C = 254 (460)
α = 1.0 (0.04) within cargo spaces
= 0.5 (0.02) for other than cargo spaces
Where the plating of collision bulkheads forms tank boundaries, the plating is not to be less than required
for bulkhead plating obtained in 5C-5-6/19.1.

21.3 Stiffeners (2002)

The net section modulus of each stiffener, in association with the effective plating to which it is attached, is
to be not less than that obtained from the following equation:
SM = kc1c2hsl2Q cm3 (in3)
where
k = 9.75 (0.0051)
c1 = 0.56
c2 = 0.85
s = spacing of the stiffeners, in m (ft)
h = distance, in m (ft), from the middle of l to the deepest equilibrium waterline in the
one compartment damaged condition
h is to be not less than the distance to the bulkhead deck at center unless a deck lower
than the uppermost continuous deck is designated as the freeboard deck, as allowed
in 3-1-1/13.1. In such case, h is to be not less than the distance to the designated
freeboard deck at center.
Where the distance indicated above is less than 6.10 m (20 ft), h is to be taken as 0.8
times the distance plus 1.22 m (4 ft).

744 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

l = span of stiffeners between effective supports, as shown in 5C-5-4/Figure 6, in m (ft)

Q = material conversion factor, as specified in 5C-5-4/5
The effective breadth of plating, be, is as defined in 5C-5-4/11.5.
For stiffeners on bulkheads forming a tank boundary, the net section modulus is not to be less than required
for stiffeners obtained in 5C-5-6/19.3.

21.5 Girders and Webs

21.5.1 Section Modulus (2002)
Each girder and web which supports bulkhead stiffeners is to have a net section modulus SM not
less than obtained from the following equation:
SM = k c1c2hsl2Q cm3 (in3)
where
k = 5.925 (0.0031)
c1 = 1.0
c2 = 0.95
h = vertical distance, in m (ft), to the deepest equilibrium waterline in the one
compartment damaged condition from the middle of s in the case of girders,
and from the middle of l in the case of webs
h is to be not less than the distance to the bulkhead deck at center unless a
deck lower than the uppermost continuous deck is designated as the freeboard
deck, as allowed in 3-1-1/13.1. In such case, h is to be not less than the
distance to the designated freeboard deck at center.
Where the distance indicated above is less than 6.10 m (20 ft), h is to be
taken as 0.8 times the distance plus 1.22 m (4 ft).
s = sum of half lengths (on each side of girder or web) of the stiffener supported,
in m (ft)
l = span measured between the heels of end attachments, in m (ft). Where an
effective bracket is fitted at the bulkhead, the length l may be modified as
shown in 5C-5-4/Figure 9.
Q = material factor, as specified in 5C-5-4/5
Where the girders and webs form tank boundaries, the net section modulus is to comply with
5C-5-6/19.5.
21.5.2 Proportions
The depth and net thickness of the girders and webs are to be not less than dw and tw, respectively,
as defined below:
dw = 83.3l + 0.25dS mm

= l + 0.25dS in.
tw = dw/100 + 2.0 mm need not exceed 10.5 mm (0.41 in.)
= dw/100 + 0.08 in.

dS is the depth of the slots, in mm (in.), for the stiffeners and l is as defined above.
Where the girders and webs form tank boundaries, the proportions are to be in compliance with
5C-5-6/19.5.

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

23 Structure Strengthening for Impact Loads

Where the hull structure is subject to impact loads as specified in 5C-5-3/5.3 or 5C-5-3/11, appropriate
strengthening is to be required, as outlined below.

23.1 Bottom Slamming

When bottom slamming as specified in 5C-5-3/11.1 is considered, the bottom structure in the region of the
flat of bottom forward of 0.25L from the FP is to be in compliance with the following requirements.
23.1.1 Bottom Plating
The net thickness of the flat of bottom plating forward of 0.25L from the FP is not to be less than
t1 or t2, whichever is greater, obtained from the following equations:
t1 = 0.73s(k1 ps /f1)1/2 mm (in.)
t2 = 0.73s(k2 ps /f2)1/2 mm (in.)
where
s = spacing of longitudinals or transverse stiffeners, in mm (in.)
k1 = 0.342 for longitudinally stiffened plating

= 0.5k2 for transversely stiffened plating

k2 = 0.5 for longitudinally stiffened plating
= 0.342 for transversely stiffened plating
k = (3.075(α)1/2 − 2.077)/(α + 0.272) (1 ≤ α ≤ 2)
= 1.0 (α > 2)
α = aspect ratio of the panel (longer edge/shorter edge)
ps = the maximum slamming pressure = ku psi
psi = nominal bottom slamming pressure, as specified in 5C-5-3/11.1 at the center
of the panel, in N/cm2 (kgf/cm2, lbf/in2)
ku = slamming load factor = 1.1
f1 = permissible bending stress in the longitudinal direction, in N/cm2 (kgf/cm2,
lbf/in2)
= 0.85 Sm fy forward of 0.125L from the FP
= 0.75 Sm fy between 0.125L and 0.25L, from the FP
f2 = permissible bending stress in the transverse direction, in N/cm2 (kgf/cm2,
lbf/in2)
= 0.85 Sm fy
Sm and fy are as defined in 5C-5-4/11.3.1.

23.1.2 Bottom Longitudinals and Frames

The section modulus of the frame, including the associated effective plating on the flat of bottom
plating forward of 0.25L from the FP, is not to be less than that obtained from the following equation:
SM = M/fb cm3 (in3)

M = pssl2103/k N-cm (kgf-cm, lbf-in)

746 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

where
k = 16 (16, 111.1)
ps = the maximum slamming pressure = ku psi
psi = nominal bottom slamming pressure, as specified in 5C-5-3/11.1, at the
midpoint of the span l, in N/cm2 (kgf/cm2, lbf/in2)
ku = slamming load factor = 1.1
s = spacing of longitudinal or transverse frames, in mm (in.)
l = the unsupported span of the frame, as shown in 5C-5-4/Figure 6, in m (ft)
fb = 0.9 Sm fy for transverse and longitudinal frames in the region forward of
0.125L from the FP, in N/cm2 (kgf/cm2, lbf/in2)
= 0.8 Sm fy for longitudinal frames in the region between 0.125L and 0.25L
from the FP, in N/cm2 (kgf/cm2, lbf/in2)
The effective breadth of plating, be, is as defined in 5C-5-4/11.5.
Struts connecting the bottom and inner bottom longitudinals are not to be fitted.

23.3 Bowflare Slamming

When bowflare slamming as specified in 5C-5-3/11.3 is considered, the side shell structure above the
waterline in the region between 0.0125L and 0.25L from the FP is to be in compliance with the following
requirements in addition to 5C-5-6/5.
23.3.1 Side Shell Plating (2007)
The net thickness of the side shell plating between 0.0125L and 0.25L from the FP is not to be less
than t1 or t2, whichever is greater, obtained from the following equations:
t1 = 0.73s(k1 ps/f1)1/2 in mm (in.)
1/2
t2 = 0.73s(k2 ps /f2) in mm (in.)
where
s = spacing of longitudinal or transverse frames, in mm (in.)
k1 = 0.342 for longitudinally stiffened plating
= 0.5 k2 for transversely stiffened plating
k2 = 0.5 for longitudinally stiffened plating
= 0.342 for transversely stiffened plating
k = (3.075(α) 1/2
− 2.077)/(α + 0.272), (1 ≤ α ≤ 2)
= 1.0 (α > 2)
α = aspect ratio of the panel (longer edge/shorter edge)
ps = the design slamming pressure = ku pij
pij = nominal bowflare slamming pressure, as specified in 5C-5-3/11.3.1, at the
center of the supported panel under consideration, in N/ cm2 (kgf/cm2, lbf/in2)
ku = slamming load factor = 1.1
f1 = 0.9 Sm fy for side shell plating in the region between 0.0125L and 0.125L,
from the FP, in N/cm2 (kgf/cm2, lbf/in2)
= 0.75 Sm fy for side shell plating in the region between 0.125L and 0.25L,
from the FP, in N/cm2 (kgf/cm2, lbf/in2)
f2 = 0.9 Sm fy, in N/cm2 (kgf/cm2, lbf/in2)
Sm and fy are as defined in 5C-5-4/11.3.1.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 747
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

23.3.2 Side Longitudinals and Frames

The net section modulus of the frame, including the associated effective plating, is not to be less
than that obtained from the following equation:
SM = M/fb in cm3 (in3)

M = pssl2103/k in N-cm (kgf-cm, lbf-in)

where
k = 16 (16, 111.1)
l = unsupported span of the frame, as shown in 5C-5-4/Figure 6, in m (ft)
ps = the maximum slamming pressure, in N/cm2 (kgf/cm2, lbf/in2), as defined in
5C-5-6/23.3.1 above, at the midpoint of the span l
s = spacing of longitudinal or transverse frames, in mm (in.)
fb = 0.9 Sm fy for transverse and longitudinal frames in the region between
0.0125L and 0.125L, from the FP
= 0.8 Sm fy for longitudinal frames in the region between 0.125L and 0.25L
from the FP, in N/cm2 (kgf/cm2, lbf/in2)
The effective breadth of plating, be, is as defined in 5C-5-4/11.5.
Sm and fy are as defined in 5C-5-4/11.3.1.

23.3.3 Side Transverses and Stringers (1 July 2008)

Note: When the scantlings of side transverses and stringers are evaluated, the section modulus and effective
shear area are to be calculated with due consideration to the inclined angle (5C-5-1/3). If the flange of such
a member is constructed in a less effective way to resist bending (such as snipped close to the most critical
area), the section modulus is to be calculated without considering the contribution from the flange.
23.3.3(a) Section Modulus. The net section modulus of side transverse and stringer, in association
with the effective side shell plating, is not to be less than that obtained from the following equation:
SM = M/fb in cm3 (in3)
i) Longitudinally Framed Side Shell
For side stringer
M = c1c2 psltls105/k in N-cm (kgf-cm, lbf-in)
For side transverse, M is not to be less than M1 or M2, whichever is greater

M1 = c3 ps l 2t (1.0 − c4φ)105/k in N-cm (kgf-cm, lbf-in)

M2 = p1s l 2t 105/k in N-cm(kgf-cm, lbf-in)

where
k = 12 (12, 44.64)
c1 = 0.125 + 0.875φ, but not less than 0.3
Coefficients c2, c3 and c4 are given in the 5C-5-6/Tables 1, 2 and 3, respectively.
p = slamming pressure = ku pij, in kN/m2 (tf/m2, Ltf/ft2)

For side transverse; p is taken at the midspan of lt of the side transverse under consideration.

For side stringer; p is taken at the midspan of ls of the stringer under consideration.

748 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

p1 = slamming pressure, in kN/m2 (tf/m2, Lft/ft2), at the midspan of lt1 of the side
transverse under consideration.
= ku pij
ku = slamming load factor = 0.71
pij = nominal bowflare slamming pressure, in kN/m2 (tf/m2, Lft/ft2), as defined in
5C-5-3/11.3.1
s = sum of half distances on each side of a transverse, in m (ft), between the side
transverse under consideration and adjacent side transverses or transverse
bulkhead (strength bulkhead)
= 0.45ls for stringer
φ = 1/(1 + α)
α = 1.33(It /Is)(ls /lt)3
It = moment of inertia, in cm4 (in4), (with effective side plating) of side transverse.
It is to be taken as average of those at the middle of each span lt1 between
side stringers or side stringer and platform (flat), clear of the bracket
Is = moment of inertia, in cm4 (in4), (with effective side plating) of side stringer
at the middle of the span ls clear of the bracket
lt = spans, in m (ft), of the side transverse under consideration between platforms
or flats, as shown in 5C-5-6/Figure 3b
ls = spans, in m (ft), of the side stringer under consideration between transverse
bulkheads or strength bulkheads, as shown in 5C-5-6/Figure 3a
lt1 = span, in m (ft), of side transverse under consideration between stringers, or
stringer and platform (flat), as shown in 5C-5-6/Figure 3b
fb = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.75 Sm fy
Sm and fy are as defined in 5C-5-4/11.3.1.
The bending moment for side transverse below stringer (or below the platform if no stringer is
fitted) is not to be less than 80% of that for side transverse above stringer (or above platform if no
stringer is fitted).

TABLE 1
Coefficient c2 (1 July 2008)
Number of Side Stringers Between Platforms (flats) No Stringer One Stringer More than One Stringer
Stringer 0.0 1.06 0.94

TABLE 2
Coefficient c3 (1 July 2008)
Number of Side Stringers Between Platforms (flats) No Stringer One Stringer More than One Stringer
Transverse 1.0 0.80 0.80

TABLE 3
Coefficient c4
Number of Side Stringers Between Platforms (flats) No Stringer One Stringer More than One Stringer
Transverse 0.0 0.75 0.80

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 749
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

FIGURE 3
Definition of Spans

he

he h
e SIDE
SHEL
L
he
ls1
TRANSV. BHD OR STRENGTH BHD

ls

ls1

OR STRENGTH BHD
l1

TRANSV. BHD
l

a. Stringer

PLATFORM FLAT

he

l1
lt1
he

he lt l

lt1
SIDE SHELL

l1

he
PLATFORM FLAT

b. Transverse

750 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

ii) Transversely Framed Side Shell

For side transverse
M = c1 psltls105/k in N-cm (kgf-cm, lbf-in)
For side stringer, M is not to be less than M1 or M2, whichever is greater

M1 = c2 ps l 2s (1.0 – c3φ1)105/k in N-cm (kgf-cm, lbf-in)

M2 = 1.30p1 s l 2s1 105/k in N-cm (kgf-cm, lbf-in)

where
k = 12 (12, 44.64)
c1 = 0.12 + 0.82φ1, but not to be taken less than 0.1
If no side transverses are fitted between transverse bulkheads or strength bulkheads
c2 = 1.3
c3 = 0
If side transverses are fitted between transverse bulkheads or strength bulkheads
c2 = 0.94
c3 = 0.8
p is as defined in 5C-5-6/23.3.3(a)i) above.
p1 = slamming pressure, in kN/m2 (tf/m2, Lft/ft2), at the midspan of ls1 of the side
stringer under consideration.
= ku pij
pij = nominal bowflare slamming pressure, in kN/cm2 (tf/m2, Ltf/ft2), as defined in
5C-5-3/11.3.1
ku = slamming load factor = 0.71
s = sum of half distances, in m (ft), between side stringer under consideration
and adjacent side stringers or platforms (flats), on each side of the stringer.
= for transverse; 0.45lt

φ1 = α/(1 + α)
ls1 = span, in m (ft), of side stringer under consideration between side transverses,
or side transverse and transverse bulkhead (strength bulkhead), as shown in
5C-5-6/Figure 3a
fb = permissible bending stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.75 Sm fy
Sm and fy are as defined in 5C-5-4/11.3.1.

lt, ls and α are as defined in 5C-5-6/23.3.3(a)i) above.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 751
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

23.3.3(b) Sectional Area of Web. The net sectional area of the web portion of the side transverse
and side stringer is not to be less than that obtained from the following equation:
A = F/fs cm2 (in2)
i) Longitudinally Framed Side Shell
For side stringer
F = kc1 pls103 in N (kgf, lbf)
For side transverse, F is not to be less than F1 or F2, whichever is greater

F1 = kc2 pls(1.0 − c3φ − 2he /l)103 in N (kgf, lbf)

F2 = 2kc2 p1s(0.5l1 − he)103 in N (kgf, lbf)

where
k = 0.5 (0.5, 1.12)
c2 = 1.0
Coefficients c1, and c3 are given in the 5C-5-6/Table 4 and 5C-5-6/Table 5, respectively.
l = span, in m (ft), of the side transverse under consideration between platforms
(flats), as shown in 5C-5-6/Figure 3b
l1 = span, in m (ft), of the side transverse under consideration between side
stringers or side stringer and platforms (flats), as shown in 5C-5-6/Figure 3b
he = length, in m (ft), of the end bracket of the side transverse, as shown in
5C-5-6/Figure 3b
To obtain F1, he is equal to the length of the end bracket at the end of span l of side transverse, as
shown in 5C-5-6/Figure 3b.
To obtain F2, he is equal to the length of the end bracket at the end of span l1 of side transverse, as
shown in 5C-5-6/Figure 3b.
fs = permissible shear stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.45 Sm fy
Sm and fy are as defined in 5C-5-4/11.3.1.

p, p1, φ and s are as defined in 5C-5-6/23.3.3(a)i).

The shear force for the side transverse below the lowest stringer (or below the platform if no
stringer is fitted) is not to be less than 110% of that for the side transverse above the top stringer
(or above the platform if no stringer is fitted).

TABLE 4
Coefficient c1 (1 July 2008)
Number of Side Stringers Between Platforms (flats) No Stringer One Stringer More than One Stringer
Stringers 0.0 0.61 0.72

TABLE 5
Coefficient c3
Number of Side Stringers Between Platforms (flats) No Stringer One Stringer More than One Stringer
Transverses 0.0 0.5 0.6

752 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

ii) Transversely Framed Side Shell

For side transverse
F = kc1 pls103 in N (kgf, lbf)
For side stringer, F is not to be less than F1 or F2, whichever is greater

F1 = 1.18kpls(1.0 − 0.6φ1 − 2he /l)103 in N (kgf, lbf)

F2 = 2.4kp1 s (0.5l1 − he)103 in N (kgf, lbf)

where
k = 0.5 (0.5, 1.12)
c1 = 0.1 + 0.7φ1, but not to be taken less than 0.2
l = span, in m (ft), of the side stringer under consideration between transverse
bulkheads, as shown in 5C-5-6/Figure 3a
l1 = span, in m (ft), of the side stringer under consideration between side transverses
or side transverse and bulkhead, as shown in 5C-5-6/Figure 3a
he = length, in m (ft), of the end bracket of the side stringer under consideration,
as shown in 5C-5-6/Figure 3a
To obtain F1, he is equal to the length of the end bracket at the end of span l of side stringer, as
shown in 5C-5-6/Figure 3a.
To obtain F2, he is equal to the length of the end bracket at the end of span l1 of side stringer, as
shown in 5C-5-6/Figure 3a.
fs = permissible shear stress, in N/cm2 (kgf/cm2, lbf/in2)
= 0.45 Sm fy
Sm and fy are as defined in 5C-5-4/11.3.1.

p, p1, φ and s are as defined in 5C-5-6/23.3.3(a)ii) above.

23.3.3(c) Depths of Side Transverses and Stringers. The depths of side transverses and stringers
dw are neither to be less than that obtained from the following equations nor be less than 2.5 times
the depth of the slots, respectively.
i) Longitudinally Framed Side Shell
For side transverse
If side stringer is fitted between platforms (flats)
dw = (0.08 + 0.80α)lt for α ≤ 0.05

= (0.116 + 0.084α)lt for α > 0.05 and need not be greater than 0.2lt
If no side stringer is fitted between platforms (flats):
dw ≥ 0.2lt
For side stringer
dw = (0.42 − 0.9α)ls for α ≤ 0.2

= (0.244 − 0.0207α)ls for α > 0.2

α is not to be taken greater than 8.0 to determine the depth of the side stringer.
lt, ls and α are as defined in 5C-5-6/23.3.3(a)i), above.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 753
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

ii) Transversely Framed Side Shell

For side stringer
If side transverse is fitted between transverse bulkheads
dw = (0.08 + 0.80α1)ls for α1 ≤ 0.05

= (0.116 + 0.084α1)ls for α1 > 0.05 and need not be greater than 0.2ls
If no side transverse is fitted between transverse bulkheads
dw = 0.2ls
For side transverse
dw = (0.277 − 0.385α1)lt for α1 ≤ 0.2

= (0.204 − 0.0205α1)lt for α1 > 0.2

α is not to be taken greater than 7.5 to determine the depth of the side transverse.
where
α1 = 1/α
lt, ls and α are as defined in 5C-5-6/23.3.3(a)i), above.

23.5 Bow Strengthening

When impact loads on bow, as specified in 5C-5-3/5.3.4, is considered, the side shell structure above the
waterline in the region forward of collision bulkhead is to be in compliance with the following requirements
in addition to 5C-5-6/5.
23.5.1 Side Shell Plating (1999)
The net thickness of the side shell plating is not to be less than t3, obtained from the following
equations:
t3 = 0.73sk(k3 pb /f3)1/2 in mm (in.)
where
s = spacing of longitudinal or transverse frames, in mm (in.)
k3 = 0.5

k = (3.075(α)1/2 − 2.077)/(α + 0.272), (1 ≤ α ≤ 2)

= 1.0 (α > 2)
α = aspect ratio of the panel (longer edge/shorter edge)
pb = the design bow pressure = ku pbij
pbij = nominal bow pressure, as specified in 5C-5-3/5.3.4(a), at the center of the
supported panel under consideration, in N/cm2 (kgf/cm2, lbf/in2)
ku = impact load factor = 1.1
f3 = 0.85 Sm fy, in N/cm2 (kgf/cm2, lbf/in2)
Sm and fy are as defined in 5C-5-4/11.3.1.

754 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

23.5.2 Side Longitudinals and Frames

The net section modulus of the frame, including the effective plating, is not to be less than that
obtained from the following equation:
SM = M/fbi in cm3 (in3)

M = pbsl2103/k in N-cm (kgf-cm, lbf-in)

where
k = 16 (16, 111.1)
l = unsupported span of the frame, as shown in 5C-5-4/Figure 6, in m (ft)
pb = the maximum bow pressure, in N/cm2 (kgf/cm2, lbf/in2), as defined in
5C-5-6/23.5.1 above, at the midpoint of the span l
s = spacing of longitudinal or transverse frames, in mm (in.)
fbi = 0.9 Sm fy for transverse and longitudinal frames
The effective breadth of plating, be, is as defined in 5C-5-4/11.5.

25 Aftbody and Machinery Space Structure

25.1 Bottom Structure

25.1.1 Bottom Shell Plating
The minimum net thickness of the bottom shell plating is not to be less than t, obtained from the
following equations and is not to extend for more than 0.1L from the aft end.
Between the midship 0.4L and 0.1L from the aft end, the thickness of the plating may be gradually
tapered.
t = 0.03(L + 29) + 0.009s mm for L ≤ 305 m

t = (10.70 + 0.009s) D / 35 mm for L > 305 m

t = 0.00036(L + 95) + 0.009s in. for L ≤ 1000 ft

t = (0.402 + 0.009s) D / 114.8 in. for L > 1000 ft

where
s = after peak frame spacing, in mm (in.)
L = length of vessel, as defined in 3-1-1/3.1, in m (ft)
D = molded depth, as defined in 3-1-1/7.1, in m (ft), or 35 m (114.8 ft),
whichever is greater
The net bottom-shell plating where constructed of higher-strength material is not to be less in
thickness than that obtained from the following equation:

thts = [tms − C] [(Q + 2 Q )/3] + C

where
thts = net thickness of higher-strength material, in mm (in.)
tms = net thickness, in mm (in.), of ordinary-strength steel, as required above
Q = material conversion factor, as specified in 5C-5-4/5
C = 3.3 (0.13)

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 755
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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

In determining the thickness of bottom shell plating constructed of higher-strength material and
transversely framed, the critical buckling stress of the plating is to be checked in accordance with
Appendix 5C-5-A2.
Shell plating is also not to be less in thickness than required by 5C-5-6/25.17 for deep tanks.
25.1.2 Bottom Longitudinals and Transverse Frames
Frames are not to have less strength than is required in 5C-5-6/25.1.2(a) and 5C-5-6/25.1.2(b)
below, respectively. In way of deep tanks, they are not to have less strength than is required in
5C-5-6/25.17 for stiffeners on deep-tank bulkheads.
25.1.2(a) Bottom Longitudinals. The net section modulus of the bottom longitudinal, required by
5C-5-4/11.5 for 0.4L amidship may be gradually reduced to the values required by 5C-5-6/25.5.4(a)
toward 0.1L from the end, provided that the hull girder section modulus at the location under
consideration is in compliance with the requirements given in 5C-5-4/3.1.1. In no case is the net
section modulus of each bottom shell longitudinal, in association with the effective plating to
which it is attached, to be less than obtained from the equations 5C-5-6/25.5.4(a).
25.1.2(b) Bottom Transverse Frames. The bottom shell transverse frame, in association with the
effective plating, is to be not less than that obtained from the following equation:
SM = kc1c2hsl2Q cm3 (in3)
where
k = 7.8 (0.0041)
s = spacing of the frames, in m (ft)
c1 = 1.0
c2 = 0.85

h = the vertical distance, in m (ft), from the middle of l to the load line, or two-
thirds of the distance to the bulkhead deck or freeboard deck, whichever is
greater
l = span of frames between effective supports, in m (ft), as shown in
5C-5-4/Figure 6
Q = material conversion factor, as specified in 5C-5-4/5
The effective breadth of plating, be, is as defined in 5C-5-4/11.5.

25.3 Double Bottom in Engine Space

25.3.1 Depth
The depth of the double bottom in the engine space, dDB, is not to be less than that obtained from
the following equation:

dDB = 32B + 190 d mm

dDB = 0.384B + 4.13 d in.

where
B = breadth of vessel, as defined in 3-1-1/5, in m (ft)
d = molded draft of vessel, as defined in 3-1-1/9, in m (ft)

756 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

25.3.2 Center Girder

The net thickness of center-girder plates is not to be less than that obtained from the following
equation:
t = 0.056L + 4.0 mm
t = 0.00067L + 0.157 in.
25.3.3 Solid Floors and Side Girders (2001)
The net thickness of solid floors and side girders is not to be less than that obtained from the following
equation:
t = 0.036L + 3.2 mm
t = 0.00043L + 0.126 in.
L = length of vessel, as defined in 3-1-1/3.1, in m (ft)
Solid floors are to be fitted on every frame under machinery and transverse boiler bearers. In this
arrangement, the net thickness of floors needs not exceed 12.5 mm (0.5 in.), provided the buckling
strength is proven adequate (see 5C-5-A2/3).
Where boilers are mounted on the tank top, the thickness of the floors in way of the boilers is to be
increased by 1.5 mm (0.06 in.).
Floors and side girders where constructed of higher-strength material are to be not less in thickness
than obtained from the following equation:

thts = [tms − C][(Q + 2 Q )/3] + C

where
thts = net thickness of higher-strength material, in mm (in.)
tms = net thickness, in mm (in.), of ordinary-strength steel, as required above.
Q = material conversion factor, as specified in 5C-5-4/5.
C = 1.5 (0.06)
25.3.4 Floor Stiffeners
Stiffeners spaced not more than 1.53 m (5 ft) apart are to be fitted on solid floors. Stiffeners may
be omitted on non-tight floors with transverse framing, provided the thickness of the floor plate is
increased 10% above the thickness obtained from 5C-5-6/25.3.3, above.
25.3.5 Inner-bottom Plating Thickness
The net thickness of inner-bottom plating is not to be less than that obtained from the following
equation:
t = 0.037L + 0.009s mm
t = 0.00044L + 0.009s in.
where
L = length of vessel, as defined in 3-1-1/3.1, in m (ft)
s = frame spacing, in mm (in.)
For vessels with longitudinally-framed inner bottoms, the thickness of inner-bottom plating, as
obtained above, may be reduced by 1.0 mm (0.04 in.).
The net inner-bottom plating, where constructed of higher-strength material, is to be not less in
thickness than that obtained by the following equation:

thts = [tms − C][(Q + 2 Q )/3] + C

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 757
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

where
thts = net thickness of higher-strength material, in mm (in.)
tms = net thickness, in mm (in.), of ordinary-strength steel, as required above.
Q = material conversion factor, as specified in 5C-5-4/5
C = 1.5 (0.06)
In way of engine bed plates or thrust blocks which are bolted directly to the inner bottom, the net
plating thickness is to be at least 17.5 mm (0.7 in.); the thickness is to be increased according to
the size and power of the engines. Holding down bolts are to pass through angle flanges of sufficient
breadth to take the nuts.
Also see 3-2-12/1.
Where the inner-bottom forms tank boundaries, plating is to be in compliance with 5C-5-6/25.17.1.

25.5 Side Shell Structures

25.5.1 Side Shell Plating
The minimum net thickness of the side shell plating at ends, including transom plating, is to be not
less than t, obtained from the following equations and is not to extend for more than 0.1L from the
aft end. Between the midship 0.4L and the end 0.1L, the thickness of the plating may be gradually
tapered.
t = 0.029(L + 29) + 0.009s mm for L ≤ 305 m

t = (10.20 + 0.009s) D / 35 mm for L > 305 m

t = 0.00036(L + 95) + 0.009s in. for L ≤ 1000 ft

t = (0.402 + 0.009s) D / 114.8 in. for L > 1000 ft

where
s = after peak frame spacing, in mm (in.)
L = length of vessel, as defined in 3-1-1/3.1, in m (ft)
D = molded depth, in m (ft), as defined in 3-1-1/7.1 or 35 m (114.8 ft), whichever
is greater
Where the strength deck at the ends is above the freeboard deck, the net thickness of the side shell
plating above the freeboard deck may be reduced to the thickness as given in 5C-5-6/25.5.2 below.
The required net thickness of the side shell plating is also to meet the hull girder shear strength at
the location considered.
The net thickness of side-shell plating where constructed of higher-strength material is to be not
less in thickness than that obtained from the following equation:

thts = [tms − C][(Q + 2 Q )/3] + C

where
thts = net thickness of higher-strength material, in mm (in.)
tms = net thickness, in mm (in.), of ordinary-strength steel, as required above.
Q = material conversion factor, as specified in 5C-5-4/5
C = 2.8 (0.11)
In determining the thickness of side-shell plating constructed of higher-strength material and
transversely framed, the critical buckling stress of the plating is to be checked in accordance with
Appendix 5C-5-A2.

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

Shell plating is also not to be less in thickness than required by 5C-5-6/25.17 for deep tanks.
Shell plating thickness is to be increased 25% in way of breaks of superstructures, but this
increase need not exceed 6.5 mm (0.25 in.).
25.5.2 Poop Side Plating
The net thickness, t, of the plating is not to be less than that obtained from the following equation:
t = 0.028(L + 150) + 0.006(s − S) mm
t = 0.00034(L + 492) + 0.006(s − S) in.
where
s = frame spacing. in mm (in.)
S = standard frame spacing
= 2.08L + 438 mm for L ≤ 270 m
= 0.025L + 17.25 in. for L ≤ 886 ft
= 1000 (39.4) mm (in.) for L > 270 m (886 ft)
= 610 (24) mm (in.) in way of the aft peak
L = length of vessel, as defined in 3-1-1/3.1, in m (ft), but need not be taken
more than 305 m (1000 ft)
Where constructed of higher-strength material, the plating is to be not less in thickness than that
obtained from the following equation:

thts = [tms − C][(Q + 2 Q )/3] + C

where
thts = net thickness of higher-strength material, in mm (in.)
tms = net thickness, in mm (in.), of ordinary-strength steel, as required above
Q = material conversion factor, as specified in 5C-5-4/5
C = 2.8 (0.11)
25.5.3 Stern Thruster Tunnels
The net thickness of the tunnel plating is to be not less than required by 5C-5-6/25.5.1, where s is
to be taken as the standard frame spacing S given by the equation in 5C-5-6/25.5.2, nor is the
thickness to be less than that obtained from the following equation:
t = 0.008d + 1.8 mm
t = 0.008d + 0.07 in.
d = inside diameter of the tunnel, in mm (in.), but is to be taken not less than
968 mm (38 in.)
Where the outboard ends of the tunnel are provided with bars or grids, the bars or grids are to be
effectively secured.
25.5.4 Side Longitudinals and Transverse Frames
Frames are not to have less strength than is required in 5C-5-6/25.15.2 for bulkhead stiffeners in
the same location in conjunction with the heads to the bulkhead deck. In way of deep tanks, they
are not to have less strength than is required in 5C-5-6/25.17.2 for stiffeners on deep-tank bulkheads.
Framing sections are to have sufficient thickness and depth in relation to the spans between supports.
See also 5C-5-A2/11.9.

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

25.5.4(a) Side Longitudinals. The net section modulus of each side longitudinal, in association
with the effective plating to which it is attached, is not to be less than that obtained from the following
equation:
SM = kc1c2hsl2Q cm2 (in2)
where
k = 7.8 (0.0041)
s = spacing of side longitudinals, in m (ft)
c1 = 0.95
c2 = 0.85
above 0.5D from the keel:
h = the vertical distance, in m (ft), from the side longitudinal to the bulkhead
deck, but is not to be taken less than 2.13 m (7.0 ft)
at and below 0.5D from the keel:
h = 0.75 times the vertical distance, in m (ft), from the longitudinal frame to the
bulkhead deck, but is not to be less than 0.5D
D = depth of vessel, in m (ft), as defined in 3-1-1/7.
l = span of longitudinal between effective supports, as shown in 5C-5-4/Figure 6,
in m (ft)
Q = material conversion factor, as specified in 5C-5-4/5
The effective breadth of plating, be, is as defined in 5C-5-4/11.5.
25.5.4(b) Transverse Frames. The net section modulus SM of each transverse frame, in association
with the effective plating to which it is attached, is to be obtained from the following equation:
SM = c2sl2 (h + bh1/33)(7 + 45/l3)Q cm3

SM = c2sl2 (h + bh1/100)(0.0037 + 0.84/l3)Q in3

where
s = spacing of side frames, in m (ft)
c2 = 0.85
l = the span of frames between effective supports, as defined in 5C-5-6/Figure 1,
in m (ft). The value of l for use with the equation is not to be less than 2.10
m (7 ft).
h = vertical distance, in m (ft), from the middle of l to the load line or 0.4l,
whichever is the greater, as shown in 5C-5-6/Figure 1.
b = horizontal distance, in m (ft), from the outside of the frames to the first row
of deck supports, as shown in 5C-5-6/Figure 1
h1 = vertical distance, in m (ft), from the deck at the top of the frame to the bulkhead
or freeboard deck plus the height of all cargo tween-deck spaces and one half
the height of all passenger spaces above the bulkhead or freeboard deck, or plus
2.44 m (8 ft) if that be greater. Where the cargo load differs from 715 kgf/m3
(45 lbf/ft3) multiplied by the tween-deck height in m (ft), the height of that
tween-deck is to be proportionately adjusted in calculating h1.
Q = material conversion factor, as specified in 5C-5-4/5
The effective breadth of plating, be, is as defined in 5C-5-4/11.5.

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

25.5.4(c) Transverse tween-deck Frames. The net section modulus SM of each transverse tween-
deck frame, in association with the effective plating to which it is attached, is to be not less than
that obtained from the following equation:
SM = c2(7 + 45/l3)sl2KQ cm3

SM = c2(0.0037 + 0.84/l3)sl2KQ in3

where
s = spacing of side frames, in m (ft)
c2 = 0.85

l = tween deck height or unsupported span along the frame length, as shown in
5C-5-4/Figure 6, whichever is greater, in m (ft)
K = factor appropriate to the length of vessel and type of tween decks, as shown
in 5C-5-6/Figure 1, defined as follows:
For L in m:
KA = 0.022L − 0.47
KB = 0.034L − 0.56
KC = 0.036L − 0.09 for L ≤ 180 m
KC = 0.031L + 0.83 for L > 180 m
KD = 0.029L + 1.78
For L in ft:
KA = 0.022L − 1.54
KB = 0.034L − 1.84
KC = 0.036L − 0.29 for L ≤ 590 ft
KC = 0.031L + 2.8 for L > 590 ft
KD = 0.029L + 5.84
L = length of vessel, as defined in 3-1-1/3.1, in m (ft), but need not be taken as
greater than 305 m (1000 ft)
Q = material conversion factor, as specified in 5C-5-4/5
The effective breadth of plating, be, is as defined in 5C-5-4/11.5.

25.7 Side Transverse Web Frames and Stringers

25.7.1 Transverse Web Frames
The net section modulus of each web frame, in association with the effective plating to which it is
attached, is to be not less than that obtained from the following equation:
SM = kc1c2sl2(h + bh1/45K)Q cm3

SM = kc1c2sl2(h + bh1/150K)Q in3

where
k = 4.74 (0.0025)
c1 = 1.5

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Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

c2 = 0.95
s = spacing of the web frames, in m (ft)
l = span, in m (ft), measured from the line of the inner bottom (extended to the
side of the vessel) to the deck at the top of the web frames. Where effective
brackets are fitted, the length l may be modified as shown in 5C-5-4/Figure 9.
h = vertical distance, in m (ft), from the middle of l to the load line, the value of
h is not to be less than 0.5l
h1 = vertical distance, in m (ft), from the deck at the top of the frame to the bulkhead
or freeboard deck plus the height of all cargo tween-deck spaces and one half
the height of all passenger spaces above the bulkhead or freeboard deck, or
plus 2.44 m (8 ft) if that be greater. Where the cargo load differs from 715
kgf/m3 (45 lb/ft3) multiplied by the tween-deck height in m (ft), the height of
that tween-deck is to be proportionately adjusted in calculating h1.
b = horizontal distance, in m (ft), from the outside of the frame to the first row of
deck supports, as shown in 5C-5-6/Figure 2
K = 1.0, where the deck is longitudinally framed and a deck transverse is fitted in
way of each web frame
= number of transverse frame spaces between web frames where the deck is
transversely framed
Q = material conversion factor, as specified in 5C-5-4/5
The depth and net thickness of the web are not to be less than dw and tw, respectively, as defined below:

dw = 125l mm

= 1.5l in.
tw = dw /100 + 2.5 mm need not be greater than 13.0 mm (0.51 in.)
= dw /100 + 0.1 in.

l is as defined above.
Where the webs are in close proximity to boilers, the thickness of the webs, face bars, flanges, etc.,
are to be increased 1.5 mm (0.06 in.) above the normal requirements.
Web frames in way of deep-tank are to comply with 5C-5-6/25.17
25.7.2 Stringers
The net section modulus of each side stringer, in association with the effective plating to which it
is attached, is to be not less than that obtained from the following equation:
SM = kc1c2hsl2Q cm3 (in3)
where
k = 4.74 (0.0025)
c1 = 1.5
c2 = 0.95
Q = material conversion factor, as specified in 5C-5-4/5
h = vertical distance, in m (ft), from the middle of s to the load line, or to two-
thirds of the distance from the keel to the bulkhead deck, or 1.8 m (6 ft),
whichever is greatest

762 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

s = sum of the half lengths, in m (ft), (on each side of the stringer) of the frame
supported
l = span, in m (ft), between web frames, or between web frame and bulkhead;
where brackets are fitted, the length l may be modified as shown in
5C-5-4/Figure 9
The depth and net thickness of the stringer are not to be less than dw and tw, respectively, as defined
below:
dw = 125l + 0.25ds mm

= 1.5l + 0.25ds in.

but need not exceed depth of the web frames to which they are connected
tw = 0.014L + 6.2 mm for L ≤ 200 m
= 0.007L + 7.6 mm for L > 200 m
tw = 0.00017L + 0.24 in. for L ≤ 656 ft
= 0.00008L + 0.3 in. for L > 656 ft
L = length of vessel, as defined in 3-1-1/3.1, in m (ft)
dS is the depth of the slot, in mm (in.), for the transverse frames and l is as defined above. In
general, the depth of the stringers is not to be less than three (3) times the depth of the slots or the
slots are to be fitted with filler plates.
Where the stringers are in close proximity to boilers, the thickness of the stringer plates, face bars,
flanges, etc. are to be increased 1.5 mm (0.06 in.) above the normal requirements.
Stringers in way of deep-tanks are also to comply with 5C-5-6/25.17.
25.7.3 After-peak Stringers
The after peak stringer plate net thickness t and breadth b are not to be less than that obtained from
the following equations:
t = 0.014L + 5.7 mm for L ≤ 200 m
t = 0.007L + 7.1 mm for L > 200 m
t = 0.00017L + 0.22 in. for L ≤ 656 ft
= 0.0008L + 0.28 in. for L > 656 ft
b = 2.22L + 600 mm
= 0.0266L + 23.62 in.
L = length of vessel, as defined in 3-1-1/3.1, in m (ft)
Where beams or struts are not fitted on every frame, the edge of the stringer is to be adequately
stiffened by a flange or face bar.

25.9 Decks
25.9.1 Strength Deck Plating Outside Line of Openings
The net thickness of the strength deck plating is to be not less than that required to meet the
longitudinal hull girder strength. The deck area contributing to the hull girder strength for amidship
0.4L is gradually reduced to the end of the vessel. Where bending moment envelope curves are
used to determine the required hull girder section modulus as permitted in 5C-5-4/3.1.1, the strength
deck area is to be maintained a suitable distance beyond superstructure breaks and is to be extended
into the superstructure to provide adequate structural continuity. The thickness is also to be not less
than t, specified below, except within deckhouse where the plating may be reduced by 1 mm (0.04 in.).

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

25.9.1(a) for longitudinally framed decks

t = 0.009sb + 1.4 mm

= 0.009sb + 0.055 in. for sb ≤ 760 mm (30 in.)

t = 0.006sb + 3.7 mm
= 0.006sb + 0.146 in. for sb > 760 mm (30 in.)
25.9.1(b) for transversely framed decks
t = 0.01sb + 1.3 mm

= 0.01sb + 0.05 in. for sb ≤ 760 mm (30 in.)

t = 0.0066sb + 3.9 mm
= 0.0066sb + 0.154 in. for sb > 760 mm (30 in.)
where
L = length of vessel, as defined in 3-1-1/3.1, in m (ft)
sb = spacing of deck beams, in mm (in.)
The net thickness of deck plating, for longitudinally framed decks, constructed of higher-strength
material, is to be not less than that obtained from the following equation:
thts = (tms − C) Q + C
where
c = 3.3 (0.13)
thts = net thickness of higher-strength material, in mm (in.)
tms = net thickness, in mm (in.), of ordinary-strength steel, as required above
Q = material conversion factor 0.92/ Q is to be used in lieu of Q, as specified in
5C-5-4/5 and is not to be less than 1.0.
In general, where the deck plating is constructed of higher-strength material, the critical buckling
stress of the plating of the higher-strength material is to be checked in accordance with Appendix
5C-5-A2.
The net thickness of the stringer plate is to be increased 25% in way of breaks of superstructures,
but this increase need not exceed 6.5 mm (0.25 in.).
25.9.2 Strength Deck Plating within Line of Openings
Within deckhouses, the plating may be of the thickness obtained from the following equations:
t = 0.009sb − 0.2 mm for sb ≤ 685 mm
t = 0.0039sb + 3.3 mm for sb > 685 mm

t = 0.009sb − 0.008 in. for sb ≤ 27 in.

t = 0.0039sb − 0.13 in. for sb > 27 in.
sb is as defined in 5C-5-6/25.9.1 above.

25.9.3 Poop Decks

The net thickness of exposed poop deck plating is to be not less than that obtained from 5C-5-6/25.9.2,
above.

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

25.9.4 Platform Decks in Enclosed Spaces

The net thickness of platform deck plating, including lower decks in machinery space, is to be not
less than that obtained from the following equation:

t = ksb h + a mm (in.)
but not less than 4.0 mm (0.2 in.).
where
k = 0.00394 (0.00218)
a = 0.5 (0.02)
h = tween deck height, in m (ft)
= p/n, when a design load, p, is specified
p = specified design load, in kN/m2 (kgf/m2, lbf/ft2)
n = 7.05 (715, 45)
sb is as defined in 5C-5-6/25.9.1 above.
Where the platform decks are subjected to hull girder bending, special consideration is to be given
to the structural stability of deck supporting members. Appendix 5C-5-A2 may be used.
25.9.5 Watertight Flats (1 July 2005)
Watertight flats over tunnels or forming recesses or steps in bulkheads are to be of not less thickness
than required for the plating of ordinary bulkhead at the same level obtained from 5C-5-6/25.15.1
plus 1 mm (0.04 in.).
For decks forming tops of tanks, see requirements in 5C-5-6/25.17.
25.9.6 Deck Longitudinals and Beams (1 July 2005)
25.9.6(a) Deck Longitudinals Outside the Line of Openings. The net sectional area of each deck
longitudinal or beam, in association with the effective deck plating to which it is attached, is to be
not less than that required to meet the longitudinal hull girder strength nor is the associated net
section modulus to be less than that obtained in 5C-5-6/25.9.6(b), below.
25.9.6(b) Beams. The net section modulus of each deck longitudinal or beams in association with
the effective plating is not to be less than that obtained from the following equation:
SM = kc1c2hsl2Q cm3 (in3)
where
k = 7.8 (0.0041)
s = spacing of longitudinals or beams, in m (ft)
c1 = 0.585 for beams between longitudinal deck girders.
for longitudinal beams of platform decks and between hatches
at all decks
= 0.90 for beams at deep-tank tops supported at one or both ends at the
shell or on longitudinal bulkheads
= 0.945 for longitudinals of strength decks and of effective lower decks
= 1.0 for beams at deep-tank top
c2 = 0.85

l = span of longitudinals or beams between effective supports, as shown in

5C-5-4/Figure 6, in m (ft).

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

h = height, in m (ft), as follows

= for bulkhead recesses and tunnel flats, is the height to the bulkhead deck at
the centerline; where that height is less than 6.10 m (20 ft), the value of h is
to be taken as 0.8 times the actual height plus 1.22 m (4 ft).
= for deep-tank tops, is not to be less than two-thirds of the distance from the
top of the tank to the top of the overflow; it is not to be less than 1.3 m (4.27
ft), the height to the load line or two-thirds of the height to the bulkhead or
freeboard deck, whichever is greatest.
Elsewhere, the value of h may be taken as follows.
h = 2.9 m (9.5 ft) for bulkhead or freeboard deck having no deck below
= 2.29 m (7.5 ft) for bulkhead or freeboard deck having deck below
= 1.98 m (6.5 ft) for lower decks and platform deck
= 1.68 m (5.5 ft) for poop deck above bulkhead deck
Q = material conversion factor, as specified in 5C-5-4/5
The effective breadth of plating, be, is as defined in 5C-5-4/11.5. Calculations are to be submitted
to show adequate provision against buckling where higher-strength materials is used for deck beams.
Longitudinal members are to be essentially of the same material as the plating they support.
25.9.7 Deck Girders and Transverses Clear of Tanks
25.9.7(a) Section Modulus. The net section modulus of each deck girder or transverse with the
effective plating is not to be less than that obtained from the following equation:
SM = kc1c2bhl2Q cm3 (in3)
where
k = 4.74 (0.0025)
c1 = 1.0
c2 = 0.95
b = mean breadth of the area of deck supported, in m (ft)
h = the height, in m (ft), measured at the side of the vessel, of the cargo space
wherever stores or cargo may be carried. Where the cargo load differs from
715 kgf/m3 (45 lbf/ft3) multiplied by the tween-deck height, in m (ft), the
height is to be proportionately adjusted.
Elsewhere, the value of h may be taken as follows.
h = 2.9 m (9.5 ft) for bulkhead or freeboard deck having no deck below
= 2.29 m (7.5 ft) for bulkhead or freeboard deck having deck below
= 1.98 m (6.5 ft) for lower decks and platform deck
= 1.68 m (5.5 ft) for poop deck above bulkhead deck
l = span between centers of supporting pillars, or between pillar and bulkhead,
in m (ft). Where an effective bracket is fitted at the bulkhead, the l may be
modified, as shown in 5C-5-4/Figure 9.
Q = material conversion factor, as specified in 5C-5-4/5

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

25.9.7(b) Proportions. The depth and net thickness of the girders and transverses are not to be
less than dw and tw, respectively, as defined below:

dw = kl mm (in.)
tw = dw /100 + a mm (in.)
≥ 7.5 mm (0.30 in.) for AF ≤ 38 cm2 (5.27 in2)

≥ 9.0 mm (0.35 in.) for AF ≤ 46 cm2 (8.84 in2)

≥ 11.5 mm (0.45 in.) for AF ≤ 101 cm2 (18.14 in2)
≥ 14.0 mm (0.55 in.) for AF > 165 cm2 (27.44 in2)
k = 58.3 (0.7)
a = 3.0 (0.12)
The thickness for intermediate face area may be obtained by interpolation.
AF is the net face area and l is as defined in 5C-5-6/25.9.7(a), above.

25.9.8 Deck Girders and Transverses in Tanks

The net section modulus SM of deck girders and transverses in tanks are to be obtained in the
same manner as given in 5C-5-6/25.9.7 above, except the values of c1 and h are to be as modified
below. The proportionality requirements are to be the same as given in 5C-5-6/25.9.7 above,
except that k for dw is not to be less than 83.3 (1.0).
c1 = 1.5

h = the greatest of the following distances, in m (ft), from the middle of l to:
• A point located two-thirds of the distance from the top of the tank to the
top of the overflow
• 1.3 m (4.27 ft) above the top of the tank
• The load line
• A point located at two-thirds of the distance to the bulkhead or freeboard
deck

25.11 Pillars
25.11.1 Permissible Load
The permissible load Wa of a pillar or strut is to be obtained from the following equation which
will, in all cases, be equal to or greater than the calculated load W as in 5C-5-6/25.11.2, below.
Wa = c2(k − nl/r)Ac kN(tf, Ltf)
where
c2 = 1.05
k = 12.09 (1.232, 7.83) ordinary strength steel
= 16.11 (1.643, 10.43) HT32
= 18.12 (1.848, 11.73) HT36
l = unsupported span, in cm (ft)
The length l is to be measured from the top of the inner bottom, deck or other structure on which
the pillars or struts are based to the underside of the beam or girder supported.

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Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

r = least radius of gyration, in cm (in.)

Ac = net cross sectional area of pillar or strut, in cm2 (in2)
n = 0.0444 (0.00452, 0.345) ordinary strength steel
= 0.0747 (0.00762, 0.581) HT32
= 0.0900 (0.00918, 0.699) HT36
25.11.2 Calculated Load
The calculated load W for a specific pillar is to be obtained from the following equation:
W = nbhs kN (tf, Ltf)
where
n = 7.04 (0.715, 0.02)
b = mean breadth of the area supported, in m (ft)
h = height above the area supported, as defined below, in m (ft)
For pillars spaced not more than two frame spaces, the height h is to be taken as the distance from
the deck supported to a point 3.80 m (12.5 ft) above the freeboard deck.
For wide-spaced pillars, the height h is to be taken as the distance from the deck supported to a
point 2.44 m (8 ft) above the freeboard deck, except in the case of such pillars immediately below
the freeboard deck, in which case, the value of h is not to be less than 2.9 m (9.5 ft) in measuring
the distance from the deck supported to the specified height above the freeboard deck, the height
for any tween decks devoted to crew accommodation may be taken as 1.98 m (6.5 ft).
s = mean length of the area supported, in m (ft)
25.11.3 Pillars under the Tops of Deep Tanks
Pillars under the tops of deep tanks are not to be less than required by the foregoing. They are to
be of solid sections and to have the net cross sectional area not less than A, specified below.
A = c1c2 nbhs kN (tf, Ltf)
where
c1 = 0.1035 (1.015, 0.16) ordinary strength steel
= 0.0776 (0.761, 0.12) HT32
= 0.069 (0.677, 0.107) HT36
c2 = 0.95
n = 10.5 (1.07, 0.03)
b = breadth of the area of the top of the tank supported by the pillar, in m (ft)
s = length of the area of the top of the tank supported by the pillar, in m (ft)
h = two-thirds of the distance from the top of the tank to the top of the overflow;
it is not to be less than 1.3 m (4.27 ft), the height to the load line or two-
thirds of the height to the bulkhead or freeboard deck, whichever is greatest.

25.13 After-peak
25.13.1 Center Girder and Floor Plating
The center girder continued from the midship is to extend as far aft as practicable and to be attached to
the stern frame. The net thickness of plating is not to be less than that obtained from the following
equation, but need not exceed 12.5 mm (0.5 in.), provided that it is suitably stiffened.

768 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

t = 0.036L + 3.2 mm
t = 0.00043L + 0.126 in.
L = length of vessel, as defined in 3-1-1/3.1, in m (ft)
The floors are to extend as high as necessary to give lateral stiffness to the structure and are to be
properly stiffened with flanges. If applicable, means are to be provided to prevent lateral movement
of floors.
25.13.2 Peak Frame
The net section modulus of each peak frame is to comply with 5C-5-6/25.5.4.
Peak frames in way of aft peak tank are to be in compliance with 5C-5-6/25.17.2.

25.15 Watertight Bulkheads

25.15.1 Plating (2002)
The net thickness t of bulkhead plating forming watertight boundaries is to be obtained from the
following equation:

t = sk qh /C + a mm (in.)

but not less than tmin or s/200 + c1, whichever is greater.

where
tmin = 5.5 mm (0.22 in.) within cargo spaces
5.0 mm (0.20 in.) for other than cargo spaces
c1 = 2.0 mm (0.08 in.) within cargo spaces
1.5 mm (0.06 in.) for other than cargo spaces
C = 290 (525)
a = 1.0 (0.04) within cargo spaces
= 0.5 (0.02) for other than cargo spaces
s = spacing of stiffeners, in mm (in.)

k = (3.075 α − 2.077)/(α + 0.272) (1 ≤ α ≤ 2)

= 1.0 (α > 2)
α = aspect ratio of the panel (longer edge/shorter edge)
q = 235/Y (N/mm2), 24/Y (kgf/mm2) or 34,000/Y (lbf/in2)
Y = minimum specified yield point or yield strength, in N/mm2 (kgf/mm2, lbf/in2),
for the higher-strength material or 72% of the specified minimum tensile
strength, whichever is the lesser
h = distance from the lower edge of the plate to the deepest equilibrium waterline
in the one compartment damaged condition, in m (ft)
h is to be not less than the distance to the bulkhead deck at center unless a deck
lower than the uppermost continuous deck is designated as the freeboard
deck, as allowed in 3-1-1/13.1. In such case, h is to be not less than the
distance to the designated freeboard deck at center.
The net plating thickness of afterpeak bulkheads below the lowest flat is not to be less than
required for solid floors obtained by 5C-5-6/25.13.1.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 769
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

25.15.2 Stiffeners (2002)

The net section modulus of each stiffener, in association with the effective plating to which it is
attached, is to be not less than that obtained from the following equation:
SM = kc1c2hsl2Q cm3 (in3)
where
k = 7.8 (0.0041)
c1 = 0.56
c2 = 0.85
s = spacing of the stiffeners, in m (ft)
h = distance, in m (ft), from the middle of l to the deepest equilibrium waterline
in the one compartment damaged condition
h is to be not less than the distance to the bulkhead deck at center unless a
deck lower than the uppermost continuous deck is designated as the freeboard
deck, as allowed in 3-1-1/13.1. In such case, h is to be not less than the
distance to the designated freeboard deck at center.
Where the distance indicated above is less than 6.10 m (20 ft), h is to be
taken as 0.8 times the distance plus 1.22 m (4 ft).
l = span of stiffeners between effective supports, as shown in 5C-5-4/Figure 6,
in m (ft)
Q = material conversion factor, as specified in 5C-5-4/5
The effective breadth of plating, be, is as defined in 5C-5-4/11.5.
25.15.3 Girders and Webs (Watertight Bulkhead) (2002)
25.15.3(a) Section Modulus. The net section modulus SM of each girder and web with effective
plating which support bulkhead stiffeners is not to be less than as obtained from the following equation:
SM = kc1c2hsl2Q cm3 (in3)
where
k = 4.74 (0.0025)
c1 = 1.0
c2 = 0.95
h = vertical distance, in m (ft), to the deepest equilibrium waterline in the one
compartment damaged condition from the middle of s in the case of girders,
and from the middle of l in the case of webs
h is to be not less than the distance to the bulkhead deck at center unless a
deck lower than the uppermost continuous deck is designated as the freeboard
deck, as allowed in 3-1-1/13.1. In such case, h is to be not less than the
distance to the designated freeboard deck at center.
Where the distance indicated above is less than 6.10 m (20 ft), h is to be
taken as 0.8 times the distance plus 1.22 m (4 ft).
s = sum of half lengths l on each side of girder or web of the stiffeners
supported, in m (ft)
l = span measured between the heels of end attachments, in m (ft). Where an
effective bracket is fitted at the bulkhead, the length l may be modified as
shown in 5C-5-4/Figure 9.
Q = material conversion factor, as specified in 5C-5-4/5

770 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

25.15.3(b) Proportions. The depth and net thickness of the girders and web are not to be less
than dw and tw, respectively, as defined below:

dw = 83.3l + 0.25dS mm

dw = 1.0l + 0.25dS in.

tw = dw /100 + 2.0 mm need not exceed 10.5 mm (0.41 in.)
tw = dw /100 + 0.08 in.

dS is the depth of the slots in mm (in.) for the stiffeners and l is as defined above.

25.17 Deep Tank Bulkheads

This section applies to deep tank bulkheads where the requirements in this section exceed those of
5C-5-6/25.15.
25.17.1 Plating (1 July 2005)
The net thickness t of bulkhead plating forming tank boundary is to be obtained from the following
equation:

t = sk qh /C + a mm (in.)

but not less than 5.0 mm (0.2 in.) or s/150 + a mm (in.), whichever is greater.
where
C = 254 (460)
a = 1.0 (0.04)
s = spacing of stiffeners, in mm (in.)

k = (3.075 α − 2.077)/(α + 0.272) (1 ≤ α ≤ 2)

= 1.0 (α > 2)
α = aspect ratio of the panel (longer edge/shorter edge)
q = 235/Y (N/mm2), 24/Y (kgf/mm2) or 34,000/Y (lbf/in2)
Y = minimum specified yield point or yield strength, in N/ mm2 (kgf/mm2, lbf/in2),
for the higher-strength material or 72% of the specified minimum tensile
strength, whichever is the lesser
h = the greatest of the following distances, in m (ft), from the lower edge of the
plate to:
• A point located two-thirds of the distance from the top of the tank to the
top of the overflow; where a side wing tank top extends to the underdeck
passageway (second deck), this distance need not be greater than one-
third of the distance from the second deck to the top of the overflow
• 1.3 m (4.27 ft) above the top of the tank
• The load line
• A point located at two-thirds of the distance to the bulkhead or freeboard
deck
The tops of tanks are to have plating 0.5 mm (0.02 in.) thicker than would be required for vertical
plating at the same level.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 771
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

25.17.2 Stiffeners (1 July 2005)

The net section modulus of each stiffener, in association with the effective plating to which it is
attached, is not to be less than that obtained from the following equation:
SM = kc1c2hsl2Q cm3 (in3)
where
k = 7.8 (0.0041)
c1 = 0.90
c2 = 0.85
s = spacing of the stiffeners, in m (ft)
h = the greatest of the following distances, in m (ft), from the middle of l to:
• A point located two-thirds of the distance from the top of the tank to the
top of the overflow; where a side wing tank top extends to the underdeck
passageway (second deck), this distance need not be greater than one-
third of the distance from the second deck to the top of the overflow
• 1.3 m (4.27 ft) above the top of the tank
• The load line
• A point located at two-thirds of the distance to the bulkhead or freeboard
deck
l = span of stiffeners between effective supports, as shown in 5C-5-4/Figure 6,
in m (ft)
Q = material conversion factor, as specified in 5C-5-4/5
The effective breadth of plating, be, is as defined in 5C-5-4/11.5.

25.17.3 Girders and Webs (Deep Tank Bulkhead)

25.17.3(a) Section Modulus. The net section modulus of each girder and web with effective plating
which supports bulkhead stiffeners is not to be less than that obtained from the following equation:
SM = kc1c2shl2Q cm3 (in3)
where
k = 4.74 (0.0025)
c1 = 1.5
c2 = 0.95
h = vertical distance, in m (ft), from the middle of s in the case of girders, and
from the middle of l in the case of webs to the same height to which h for the
stiffeners is measured (See 5C-5-6/25.17.2, above).
s = sum of half lengths l on each side of girder or web of the frame or stiffener
supported, in m (ft)
l = span measured between the heels of the end of the attachments, in m (ft).
Where effective brackets are fitted, the length l may be modified as defined
in 5C-5-4/Figure 9.
Q = material conversion factor, as specified in 5C-5-4/5

772 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 6 Hull Structures Beyond 0.4L Amidships 5C-5-6

25.17.3(b) Proportions. The depth and net thickness of the girders and web are not to be less
than dw and tw, respectively, as defined below:

dw = 145l + 0.25dS mm

= 1.74l + 0.25dS in.

where no struts or ties are fitted
dw = 83.3l + 0.25dS mm

= 1.0l + 0.25dS in.

where struts are fitted
tw = dw /100 + 1.5 mm need not exceed 10.0 mm (0.4 in.)
= dw /100 + 0.06 in.
dS is the depth of the slots, in mm (in.), for the stiffeners and l is as defined above. In general, the
depth is not to be less than three (3) times the depth of the slots or the slots are to be fitted with
filler plates.

25.19 Machinery Space

Care is to be taken to provide sufficient transverse strength and stiffness in the machinery space by means
of webs, plated through beams, and heavy pillars in way of deck openings and casings.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 773
PART Section 7: Cargo Safety

5C
CHAPTER 5 Vessels Intended to Carry Containers (130 meters
(427 feet) to 450 meters (1476 feet) in Length)

SECTION 7 Cargo Safety

1 Application
The provisions of Part 5C, Chapter 5, Section 7 (referred to as Section 5C-5-7) apply to vessels intended to
carry containers in respect of hazards posed by some cargoes. They form a part of the necessary condition
for assigning the class notation Container Carrier. The provisions of Part 4, specifying conditions for
assigning the machinery class notation AMS (see 4-1-1/1.5), are applicable to container carriers in addition
to the provisions of this Section.

3 Container Cargo Spaces

3.1 General Fire Protection

Except for cargo spaces covered in 5C-5-7/3.3, cargo spaces of vessels of 2,000 gross tonnage and upwards
are to be protected by a fixed gas fire extinguishing system complying with the provisions of 4-7-3/3 or by
a fire extinguishing system which gives equivalent protection.

3.3 Vessels Intended to Carry Dangerous Goods

Container holds intended for the carriage of dangerous goods are to comply with the following tabulated
requirements, except when carrying dangerous goods in limited quantities (as defined in section 18 of the
General Introduction of IMDG Code):
• 5C-5-7/Table 1 provides a description of the list of dangerous goods as defined in IMDG Code.
• 5C-5-7/Table 2 provides the application of the requirements described in 4-7-2/7.3 to container cargo
spaces.
• 5C-5-7/Table 3 provides the application of the requirements described in 4-7-2/7.3 to the different
classes of dangerous goods except dangerous goods in bulk.

5 Refrigerated Containers (2000)

Where independent refrigerated containers are carried, requirements specified in 4-8-2/3.1.1 are to be complied
with, taking into consideration electrical loads of the containers with any one generator in reserve.

774 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 7 Cargo Safety 5C-5-7

TABLE 1
Dangerous Goods Classes
Class Substance
1 Explosives
(1.1 through 1.6)
2.1 Flammable gases (compressed, liquefied or dissolved under pressure)
2.2 Non flammable gases (compressed, liquefied or dissolved under pressure)
2.3 Toxic gases
3 Flammable liquids
(3.1 through 3.3)
4.1 Flammable solids
4.2 Substances liable to spontaneous combustion
4.3 Substances which, in contact with water, emit flammable gases
5.1 Oxidizing substances
5.2 Organic peroxides
6.1 Toxic substances
6.2 Infectious substances
7 Radioactive materials
8 Corrosives
9 Miscellaneous dangerous substances and articles, that is any substance which
experience has shown, or may show, to be of such a dangerous character that the
provisions for dangerous substance transportation are to be applied.

TABLE 2
Application of Requirements to Container Cargo Spaces
4-7-2/… Requirements Container Weather
cargo spaces deck
7.3.1(a) Availability of water x x
7.3.1(b) Quantity of water x x
7.3.1(c) Underdeck cargo space cooling x -
7.3.1(d) Alternative to cooling by water x -
7.3.2 Sources of ignition x -
7.3.3 Detection system x -
7.3.4 Ventilation x (1) -
7.3.5 Bilge pumping x -
7.3.6 Personnel protection x x
7.3.7 Portable fire extinguisher - x
(2)
7.3.8 Insulation of machinery space boundary x x
7.3.9 Water-spray system - -
Notes
1 For classes 4 and 5.1 dangerous goods not applicable to closed freight
containers. For classes 2, 3, 6.1 and 8 when carried in closed freight
containers, the ventilation rate may be reduced to not less than two air
changes. For the purpose of this requirement, a portable tank is a closed
freight container.
2 Applicable to decks only.

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Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Section 7 Cargo Safety 5C-5-7

TABLE 3
Application of the Requirements in 4-7-2/7.3 to Different Classes of
Dangerous Goods, Except Solid Dangerous Goods in Bulk (1 July 2002)
Dangerous 4-7-2/Paragraph:
Goods 7.3.1 7.3.2 7.3.3 7.3.4 7.3.5 7.3.6 7.3.7 7.3.8 7.3.9 7.3.10
Class
(a) (b) (c) (d) (a) (b)
1.1 – 1.6 x x x x x x x (2) x x
1.4S x x x x x
2.1 x x x x x x x x x x
2.2 x x x x x x x
2.3 x x x x x x x x
3.1, 3.2 x x x x x x x x x x x x
≤ 23°C
3.3 x x x x x x x x
4.1 x x x x (1) x x x x x
(1)
4.2 x x x x x x x x x
4.3 x x x x x x x x x
5.1 x x x x (1) x x x (3) x x
5.2 x x x x x
6.1 liquids x x x x x x x
6.1 liquids x x x x x x x x x x x x
≤ 23°C
6.1 liquids x x x x x x x x x x x
> 23°C
≤ 61°C
6.1 solids x x x x (1) x x x
8 liquids x x x x x x
8 liquids x x x x x x x x x x x x
≤ 23°C
8 liquids x x x x x x x x x x
> 23°C
≤ 61°C
8 solids x x x x x x
9 x x (1) x (4) x x
Notes
1 When “mechanically ventilated spaces” are required by the IMDG Code, as amended.
2 Stow 3 m (10 ft) horizontally away from the machinery space boundaries in all cases.
3 Refer to the IMDG Code.
4 As appropriate to the goods being carried.

776 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
PART Appendix 1: Guide for Fatigue Strength Assessment of Container Carriers

5C
CHAPTER 5 Vessels Intended to Carry Containers (130 meters
(427 feet) to 450 meters (1476 feet) in Length)

APPENDIX 1 Guide for Fatigue Strength Assessment of

Container Carriers

1 General

1.1 Note
This Guide provides a designer oriented approach to fatigue strength assessment which may be used, for
certain structural details, in lieu of more elaborate methods such as spectral fatigue analysis. The term
assessment is used here to distinguish this approach from the more elaborate analysis.
The criteria in this Guide are developed from various sources including the Palmgren-Miner linear damage
model, S-N curve methodologies, long-term environment data of the North-Atlantic Ocean (Walden’s Data),
etc., and assume workmanship of commercial marine quality acceptable to the Surveyor. The capacity of
structures to resist fatigue is given in terms of permissible stress range to allow designers the maximum
flexibility possible.
While this is a simplified approach, a good amount of effort is still required in applying these criteria to the
actual design. For this reason, PC-based software has been developed and is available to the clients. Interested
parties are kindly requested to contact the nearest ABS plan approval office for more information.

1.3 Applicability (1998)

The criteria in this Guide are specifically written for container carriers to which Part 5C, Chapter 5 is applicable.

1.5 Loadings (1998)

The criteria have been written for ordinary wave-induced motions and loads. Other cyclic loadings, which
may result in significant levels of stress ranges over the expected lifetime of the vessel, are also to be
considered by the designer.
Where it is known that a vessel will be engaged in long-term service on a route with more severe environment,
the fatigue strength assessment criteria in this Guide are to be modified, accordingly.

1.7 Effects of Corrosion (1998)

To account for the mean wastage throughout the service life, the total stress range calculated using the net
scantlings (i.e., deducting nominal design corrosion values, see 5C-5-2/Table 1) is modified by a factor cf.
See 5C-5-A1/7.5.1.

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Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 1 Guide for Fatigue Strength Assessment of Container Carriers 5C-5-A1

1.9 Format of the Criteria (1998)

The criteria in this Guide are presented as a comparison of fatigue strength of the structure (capacity) and
fatigue inducing loads (demands) as represented by the respective stress ranges. In other words, the permissible
stress range is to be not less than the total stress range acting on the structure.
5C-5-A1/5 provides the basis to establish the permissible stress range for the combination of the fatigue
classification and typical structural joints of container carriers. 5C-5-A1/7 presents the procedures to be
used to establish the applied total stress range. 5C-5-A1/9 provides typical stress concentration factors
(SCFs) and guidelines for direct calculation of the required SCFs. 5C-5-A1/11 provides the guidance for
assessment of stress concentration factors and the selection of compatible S-N data where a fine mesh
finite element approach is used.

3 Connections to be Considered for the Fatigue Strength Assessment

3.1 General (1998)

These criteria have been developed to allow consideration of a broad variation of structural details and
arrangements so that most of the important structural details anywhere in the vessel can be subjected to an
explicit (numerical) fatigue assessment using these criteria. However, where justified by comparison with
details proven satisfactory under equal or more severe conditions, an explicit assessment can be exempted.

3.3 Guidance on Locations (1998)

As a general guidance for assessing fatigue strength for a container carrier, the following connections and
locations are to be considered:
3.3.1 Connections of Longitudinal Stiffeners to Transverse Web/Floor and to Transverse Bulkhead
3.3.1(a) Two (2) to three (3) selected side longitudinals in the region from 1.1 draft (d) to about
1/ draft (d) in the midship region and also in the region between 0.15L and 0.25L from the FP
3

3.3.1(b) One (1) to two (2) selected longitudinals from each of the following groups:
Deck longitudinals, bottom longitudinals, inner bottom longitudinals and longitudinals
on the longitudinal bulkheads.
For these structural details, the fatigue assessment is to be first focused on the flange of the longitudinal
at the rounded toe welds of attached flat bar stiffeners and brackets, as illustrated for Class F item 2)
and Class F2 item 1) and at the connection of the strut for Class G item 4) in 5C-5-A1/Table 1.
Then, the critical spots on the web plate cut-out, on the lower end of the flat bar stiffener as well
as the weld throat are also to be checked for the selected structural detail. For illustration, see
5C-5-A1/9.3.1 and 5C-5-A1/9.3.2(a), 5C-5-A1/9.3.2(b) and 5C-5-A1/9.3.2(c).
Where the longitudinal stiffener end bracket arrangements are different on opposing sides of a
transverse web or transverse bulkhead, both configurations are to be checked.
3.3.2 End Connections of Side Frame and Vertical Stiffener on Longitudinal Bulkhead
End connections of side frame and vertical stiffener on longitudinal bulkhead.
3.3.3 Connections of Transverse Web or Floor to Side Shell, Bottom, Inner Bottom or Bulkhead Plating
(for Fatigue Strength of Plating)
3.3.3(a) One (1) to two (2) selected locations of side shell plating near the summer LWL amidships
and between 0.15L and 0.25L from the FP, respectively.
3.3.3(b) One (1) to two (2) selected locations in way of bottom, inner bottom and also lower strakes
of the longitudinal bulkhead amidships, respectively.

778 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 1 Guide for Fatigue Strength Assessment of Container Carriers 5C-5-A1

3.3.4 Hatch Corners

The following locations (stations) of hatch corners, as shown in 5C-5-4/Figure 5:
3.3.4(a) Typical hatch corners within 0.4L amidships, one each at water-tight and mid-hold strength
bulkheads, station D and D′.
3.3.4(b) Hatch corners immediately forward and aft of the engine room, stations C and B.
3.3.4(c) One of the forward hatch corners subject to significant warping constraint from the
adjacent structures, station E, F or G, whichever has the greatest warping constraint.
3.3.5 Connection of Longitudinal Hatch Girders and Cross Deck Box Beams to Other Supporting
Structures
Two or more representative locations of each hatch girder and cross deck box beam connections.
3.3.6 End Bracket Connections for Transverses and Girders
One (1) to two (2) selected locations in the midship region for each type of bracket configuration.
3.3.7 End Bracket Connections for Hatch Side and Hatch End Coamings
One (1) to two (2) selected locations in the midship region for each type of bracket configuration.
3.3.8 Representative Cut-outs
Representative cut-outs in the longitudinal bulkheads, longitudinal deck girder, hatch side coamings
and cross deck box beams.
3.3.9 Other Regions and Locations
Highly stressed by fluctuating loads, as identified from structural analysis
For these structural details of items 5C-5-A1/3.3.4, 5C-5-A1/3.3.5 and 5C-5-A1/3.3.7, the value of the total
stress range, fR, as specified in 5C-5-A1/7.5.1, may be determined from fine mesh F.E.M. analyses for the
combined load cases, as specified in 5C-5-A1/7.5.2(d). Alternatively, the value of fR may be calculated by
the approximate equations given in this Guide.

3.5 Fatigue Classification

3.5.1 Welded Connections with One Load Carrying Member
Fatigue classification for structural details is shown in 5C-5-A1/Table 1.

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Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 1 Guide for Fatigue Strength Assessment of Container Carriers 5C-5-A1

TABLE 1
Fatigue Classification for Structural Details (1998)
Long-term
Permissible
Distribution
Stress Range
Parameter
Class
Designation Description γ kgf/mm2
B Parent material, plates or shapes as rolled or draw, with no flame- 0.7 92.2*
cut edges 0.8 75.9
0.9 64.2
1.0 55.6

C 1) Parent material with automatic flame-cut edges 0.7 79.2

2) Full penetration seam welds or longitudinal fillet welds made by 0.8 63.9
an automatic submerged or open are process, and with no stop- 0.9 53.3
start positions within the length.
1.0 45.7

D 1) Full penetration butt welds made either manually or by an 0.7 59.9

automatic process other than submerged arc, from both sides, in 0.8 47.3
downhand position.
0.9 38.9
2) Weld in C-2) with stop-start positions within the length 1.0 32.9

E 1) Full penetration butt welds made by other processes than those 0.7 52.8
specified under D-1) 0.8 41.7
2) Full penetration butt welds made form both sides between plates 0.9 34.2
of unequal widths or thicknesses 1.0 29.0
2a 2b
E
4 1
TAPER
E
1 3
TAPER

3) Welds of brackets and stiffeners to web plat of girders

780 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 1 Guide for Fatigue Strength Assessment of Container Carriers 5C-5-A1

TABLE 1 (continued)
Fatigue Classification for Structural Details (1998)
Long-term
Permissible
Distribution
Stress Range
Parameter
Class
Designation Description γ kgf/mm2
F 1) Full penetration butt weld made on a permanent backing strip 0.7 44.7
0.8 35.3
2) Rounded fillet welds as shown below 0.9 29.0
1.0 24.5

2a 2b
TRANSVERSE OR FLOOR

Y
F
F F
LONGITUDINAL

SHELL OR BOTTOM PLATING

"Y" IS REGARDED AS A NON-LOAD CARRYING F
MEMBER

3) Welds of brackets and stiffeners to flanges

EDGE DISTANCE ≥ 10mm

4) Attachments on plate or face plate
F

EDGE DISTANCE ≥ 10mm

(Class G for edge distance < 10 mm)

F2 Fillet welds as shown below with rounded welds and no 0.7 39.3
1)
undercutting 0.8 31.1
0.9 25.5
1a 1b

Y Y

F F F F
2 2 2 2

"Y" is a non-load carrying member

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TABLE 1 (continued)
Fatigue Classification for Structural Details (1998)
Long-term
Distribution Permissible Stress
Parameter Range
Class
Designation Description γ kgf/mm2
Fillet welds with any undercutting at the corners dressed out by 1.0 21.6
2)
local grinding

2b)
2a)

F2

F2

F2 F2

Fillet welds in F2 – 1) without rounded tow welds or with limited 0.7 32.8
G 1)
minor undercutting at corners or bracket toes 0.8 25.9
2) Fillet welds in F2 – 2) with minor undercutting 0.9 21.3
3) Doubler on face plate or flange, small deck openings 1.0 18.0
4) Overlapped joints as shown below
G

I I
G

I-
G I G

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TABLE 1 (continued)
Fatigue Classification for Structural Details (1998)
Long-term
Distribution Permissible Stress
Parameter Range
Class
Designation Description γ kgf/mm2
W 1) Fillet welds in G - 3) with any undercutting at the toes 0.7 28.3
0.8 22.3
2) Fillet welds - weld throat 0.9 18.4
1.0 15.5

1) The permissible stress range can not be taken greater that two times the specified minimum tensile strength of the
material.
2) To obtain the permissible stress range in SI and U.S. Units, the conversion factors of 9.807 (N/mm2) and 1422 (lb/in2)
can be used, respectively.

3.5.2 Welded Joint with Two or More Load Carrying Members

For brackets connecting two or more load carrying members, an appropriate stress concentration
factor (SCF) determined from fine mesh 3D or 2D finite element analysis is to used. In this connection,
the fatigue class at bracket toes may be upgraded to class E. Sample connections are illustrated
below with/without SCF.

TABLE 2
Welded Joint with Two or More Load Carrying Members
a Connections of Longitudinal and Stiffener

E with SCF E with SCF

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TABLE 2 (continued)
Welded Joint with Two or More Load Carrying Members
b Connections of Longitudinal Deck Girders and Cross Deck Box
Beams to Other Supporting Structures

A-A C B

HATCH COAMING TOP

E WITH SCF

E WITH SCF

E WITH SCF
E WITH C B
SCF

D A
B-B
HATCH COAMING TOP

STRENGTH DECK

E WITH SCF

CROSS BOX CIRDER BOTTOM

D
W.T. BHD

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TABLE 2 (continued)
Welded Joint with Two or More Load Carrying Members
C-C D

HATCH COAMING TOP

C WITH SCF
STRENGTH DECK E WITH SCF

C WITH SCF

LONGITUDINAL DECK GIRDER BOTTOM E WITH SCF

CROSS DECK BOX GIRDER BOTTOM

D-D
Z

Y Y

z
Z
CL

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TABLE 2 (continued)
Welded Joint with Two or More Load Carrying Members
c Discontinuous Hatch Side Coaming
1) without face plate Hatch End Coaming

Hatch Side Coaming Top

Strength Deck

C with SCF

2) with face plate Hatch End Coaming

Hatch Side Coaming Top

Strength Deck

E with SCF

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TABLE 2 (continued)
Welded Joint with Two or More Load Carrying Members
d Hatch Corners

Circular Corner

D WITH SCF

C WITH SCF

D WITH SCF

Double Curvature

D WITH SCF

C WITH SCF
R2

D WITH SCF
R1

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TABLE 2 (continued)
Welded Joint with Two or More Load Carrying Members
Cut-out Radius

D WITH SCF

C WITH SCF

D WITH SCF

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TABLE 2 (continued)
Welded Joint with Two or More Load Carrying Members
End Connections at Lower Deck

Side Deck
fRS

fRC
Fatique Class: F2
or
fR = α ( fRS2 + fRC2 )1/2

Cross Deck
Fatique Class :
E with SCF where α = 1.25
fRS = Cf (fRG1 + fRL1)
fRC = Cf (fRG2 + fRL2)
fRG1 ,fRL1, fRG2 and fRL2
are as specified in 5C-5-A1/9.5.1
Cf is defined in 5C-5-A1/7.5.1

Side Deck
fRS
fRC

Fatique Class: F2
Cross Deck

fR = ( fRS2 + fRC2 )1/2

Side Deck
fRS
fRC

Fatique Class: F
or fR = fRS
Cross Deck

Fatique Class :
E with SCF see 5C-5-A1/9.5.1

Fatique Class: F
fR = fRC

Note: Thickness of brackets is to be not less than that of cross deck plating in the same location (level).
For fitting of cell guide, no cut nor welding to the brackets is allowed.

5 Permissible Stress Range

5.1 Assumption (1998)

The fatigue strength of a structural detail under the loads specified here in terms of a long term, permissible
stress range is to be evaluated using the criteria contained in this section. The key assumptions employed
are listed below for guidance.
• A linear cumulative damage model (i.e., Palmgren-Miner’s Rule) has been used in connection with the
S-N data in 5C-5-A1/Figure 1 (extracted from Ref. 1*).
* Ref. 1: “Offshore Installations: Guidance on Design, Construction and Certification”, Department of Energy, U.K.,
Fourth Edition - 1990, London: HMSO

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• Cyclic stresses due to the loads in 5C-5-A1/7 have been used and the effects of mean stress have been
ignored.
• The target design life of the vessel is taken to be 20 years.
• The long-term stress ranges on a detail can be characterized by using a modified Weibull probability
distribution parameter (γ).
• Structural details are classified and described in 5C-5-A1/Table 1, “Fatigue Classification of Structural
Details”.
• Simple nominal stress (e.g., determined by P/A and M/SM) is the basis of fatigue assessment rather
than more localized peak stress in way of weld.
The structural detail classification in 5C-5-A1/Table 1 is based on joint geometry and direction of the
dominant load. Where the loading or geometry is too complex for a simple classification, a finite element
analysis of the details is to be carried out to determine the stress concentration factors. 5C-5-A1/11 contains
guidance on finite element analysis modeling to determine stress concentration factors for weld toe locations
that are typically found at longitudinal stiffener end connections.

5.3 Criteria (1998)

The permissible stress range obtained using the criteria in 5C-5-A1/5 is to be not less than the fatigue
inducing stress range obtained from 5C-5-A1/7.

5.5 Long Term Stress Distribution Parameter, γ (1998)

In 5C-5-A1/Table 1, the permissible stress range is given as a function of the long-term distribution parameter,
γ, as defined below.
γ = ms γo
where
ms = 1.05 for deck and bottom structures of vessels with a forebody parameter,
Ar dk = 155 m2 (1667.5 ft2), as defined in 5C-5-3/11.3.
= 1.02 for deck and bottom structures of vessels with a forebody parameter,
Ar dk = 112 m2 (1205 ft2)
= 1.0 for structures elsewhere, and all structures of vessels without bowflare slamming
[Ar dk ≤ 70 m2 (753 ft2)]
For intermediate values of Ardk, ms may be obtained by linear interpolation. For Ardk > 155 m2 (1667.5 ft2),
ms is to be determined by direct calculations.
γo = 1.40 – 0.2 αL0.2 for 130 < L ≤ 305 m
= 1.54 – 0.245 α0.8L0.2 for L > 305 m
γo = 1.40 – 0.16 αL 0.2
for 427 < L ≤ 1001 ft
= 1.54 – 0.19 α0.8L0.2 for L > 1001 ft
where
α = 1.0 for deck structures, including side shell and longitudinal bulkhead structures
within 0.1D from the deck
= 0.93 for bottom structures, including inner bottom, and side shell and longitudinal
bulkhead structures within 0.1D from the bottom
= 0.86 for side shell and longitudinal bulkhead structures within the region of 0.25D
upward and 0.3D downward from the mid-depth
= 0.80 for side frames, vertical stiffeners on longitudinal bulkhead and transverse
bulkhead structures

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Appendix 1 Guide for Fatigue Strength Assessment of Container Carriers 5C-5-A1

α may be linearly interpolated for side shell and longitudinal bulkhead structures between 0.1D and 0.25D
from the deck and between 0.1D and 0.2D from the bottom.
In the calculation of γ for fatigue assessment of hatch corners, ms, given in the above equation in association
with Ar dk, is to be used in L.C.1 through L.C.4 and ms may be taken as 1.0 in other loading conditions. α may
be also taken as 1.0.
L and D are the vessel’s length and depth, as defined in 3-1-1/3.1 and 3-1-1/7.

5.7 Permissible Stress Range (1998)

5C-5-A1/Table 1 contains a listing of permissible stress ranges for various categories of structural details.
The permissible stress range is determined for the combination of the types of connections/ details, the
direction of the dominant loading and the parameter, γ, as defined in 5C-5-A1/5.5. Linear interpolation
may be used to determine the values of permissible stress range for γ between those given.
(2003) For vessels designed for a fatigue life in excess of the minimum design fatigue life of 20 years (see
5C-5-1/1.2), the permissible stress ranges (PS) calculated above are to be modified by the following equation:
PS[Yr] = C(20/Yr)1/m PS
where
PS[Yr] = permissible stress ranges for the design fatigue life for the Yr
Yr = target value of “design fatigue life” set by the applicant in 5 year increment
m = 3 for Class D through W of S-N curve, 3.5 for Class C or 4 for Class B curves
C = correction factor related to target design fatigue life considering the two-segment S-N
curves (see 5C-5-A1/Table 2A).

TABLE 2A
Coefficient, C
Long-term Stress Target Design Fatigue S-N Curve Classes
Distribution Parameter, γ Life, years, Yr B C D through W
0.7 20 1.000 1.000 1.000
30 1.004 1.006 1.011
40 1.007 1.012 1.020
50 1.010 1.016 1.028
0.8 20 1.000 1.000 1.000
30 1.005 1.008 1.014
40 1.009 1.015 1.025
50 1.013 1.021 1.035
0.9 20 1.000 1.000 1.000
30 1.006 1.010 1.016
40 1.012 1.019 1.030
50 1.017 1.026 1.042
1.0 20 1.000 1.000 1.000
30 1.008 1.012 1.019
40 1.015 1.022 1.035
50 1.020 1.031 1.049
Note: Linear interpolations may be used to determine the values of C where Yr = 25, 35 and 45

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FIGURE 1
Basic Design S-N Curves (1998)

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Appendix 1 Guide for Fatigue Strength Assessment of Container Carriers 5C-5-A1

FIGURE 1 (continued)
Basic Design S-N Curves (1998)
Notes (For 5C-5-A1/Figure 1)
a) Basic design S-N curves
The basic design curves consist of linear relationships between log(SB) and log(N). They are based upon a
statistical analysis of appropriate experimental data and may be taken to represent two standard deviations
below the mean line.
Thus the basic S-N curves are of the form:
log(N) = log(K2) – m log(SB)
where
log(K2) = log(K1) – 2σ
N is the predicted number of cycles to failure under stress range SB;
K1 is a constant relating to the mean S-N curve;

σ is the standard deviation of log N;

m is the inverse slope of the S-N curve.
The relevant values of these terms are shown in the table below.
The S-N curves have a change of inverse slope from m to m + 2 at N = 107 cycles.

Details of basic S-N curves

K1 Standard Deviation
Class K1 log10 loge m log10 loge K2

B 2.343 × 1015 15.3697 35.3900 4.0 0.1821 0.4194 1.01 × 1015

C 1.082 × 1014 14.0342 32.3153 3.5 0.2041 0.4700 4.23 × 1013
12
D 3.988 × 10 12.6007 29.0144 3.0 0.2095 0.4824 1.52 × 1012
E 3.289 × 1012 12.5169 28.8216 3.0 0.2509 0.5777 1.04 × 1012
F 1.726 × 1012 12.2370 28.1770 3.0 0.2183 0.5027 0.63 × 1012
12
F2 1.231 × 10 12.0900 27.8387 3.0 0.2279 0.5248 0.43 × 1012
G 0.566 × 1012 11.7525 27.0614 3.0 0.1793 0.4129 0.25 × 1012
W 0.368 × 1012 11.5662 26.6324 3.0 0.1846 0.4251 0.16 × 1012

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7 Calculation of Fluctuating Loads and Determination of Total Stress

Ranges

7.1 General (1998)

This section provides: 1) the criteria to define the individual load components considered to cause fatigue
damage (see 5C-5-A1/7.3.1); 2) the load combination cases to be considered for different regions of the
hull containing the structural detail being evaluated (see 5C-5-A1/7.5.2); and 3) procedures to idealize the
structural components to obtain the total stress ranges acting on the structure.

7.3 Wave-induced Loads

7.3.1 Load Components (1998)
The fluctuating load components to be considered are those induced by the seaway. They are
divided into the following three groups:
• Hull girder wave-induced moments (vertical, horizontal, and torsion), see 5C-5-3/5 and 5C-5-3/7.
• External hydrodynamic pressures, see 5C-5-3/5.3.
• Internal fluid loads (including inertial loads and added static head due to ship’s motion), see
5C-5-3/5.5.

7.5 Resulting Stress Ranges

7.5.1 Definitions (2007)
The total stress range, fR, is computed as the sum of the two stress ranges, as follows:
fR = cf cm (fRG + fRL) N/cm2 (kgf/cm2, lbf/in2)
where
fRG = global dynamic stress range, in N/cm2 (kgf/cm2, lbf/in2)
= |(fd1vi – fd1vj) + (fd1hi – fd1hj) + (fd1wi – fd1wj)|
fRL = local dynamic stress range, in N/cm2 (kgf/cm2, lbf/in2)

= cw |(fd2i + f d*2i + fd3i) – (fd2j + f d*2 j + fd3j)|

cf = adjustment factor to reflect a mean wasted condition

= 0.95
cm = 0.85 for connections of longitudinals to transverse web/floor and
transverse bulkhead in bottom part of Zone A, as specified in
5C-5-A1/7.5.2(a)
= 0.85 for connection of floor to plates in bottom part of Zone A
= 1.0 for all other locations
cw = coefficient for the weighted effects of the two paired loading patterns
= 0.75 for local dynamic stress range, as specified in 5C-5-A1/7.9.1,
5C-5-A1/7.9.2 and 5C-5-A1/7.11
= 1.0 otherwise
fd1vi, fd1vj = wave-induced component of the primary stresses produced by hull girder
vertical bending, in N/cm2 (kgf/cm2, lbf/in2), for load case i and j of the
selected pairs of combined load cases, respectively. For this purpose, kw is to
be taken as k01/2 in calculating Mw (sagging and hogging) in 5C-5-3/5.1.1

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fd1hi, fd1hj = wave-induced component of the primary stresses produced by hull girder
horizontal bending, in N/cm2 (kgf/cm2, lbf/in2), for load case i and j of the
selected pairs of combined load cases, respectively
fd1wi, fd1wj = wave-induced component of the primary stresses produced by hull girder
torsion (warping stress) moment, in N/cm2 (kgf/cm2, lbf/in2), for load case i
and j of the selected pairs of combined load cases, respectively. These
components are applicable to the structural details in 5C-5-A1/3.3.4 and
5C-5-A1/3.3.5
fd2i, fd2j = wave-induced component of the secondary bending stresses produced by the
bending of cross stiffened panels between transverse bulkheads, in N/cm2
(kgf/cm2, lbf/in2), for load case i and j of the selected pairs of combined load
cases, respectively
f d*2i , f d*2 j = wave-induced component of the additional secondary bending stresses produced
by the local bending of the longitudinal stiffener between supporting structures
(e.g., transverse bulkheads and web frames), in N/cm2 (kgf/cm2, lbf/in2), for
load case i and j of the selected pairs of combined load cases, respectively
fd3i, fd3j = wave-induced component of the tertiary bending stresses produced by the
local bending of plated elements between the longitudinal stiffeners, in
N/cm2 (kgf/cm2, lbf/in2), for load case i and j of the selected pairs of
combined load cases, respectively
For calculating the wave induced stresses, sign convention is to be observed for the respective
directions of wave-induced loads, as specified in 5C-5-3/Table 1. The wave-induced load components
are to be calculated with the sign convention for the external and internal loads and the wave-
induced local net pressure is to be taken positive toward inboard and positive upwards; however,
the total of the external static and dynamic components or the total of the internal static and dynamic
components need not be taken less than zero.
These wave-induced stresses are to be determined based on the net ship scantlings (see 5C-5-A1/1.7)
and in accordance with 5C-5-A1/7.5.2 through 5C-5-A1/7.11. The results of direct calculation,
where carried out, may also be considered.
7.5.2 Fatigue Assessment Zones and Controlling Load Combination (1998)
Depending on the location of the structural detail undergoing the fatigue assessment, different
combinations of load cases are to be used to find the appropriate stress range as indicated below
for indicated respective zones.
7.5.2(a) Zone A. Zone A consists of deck and bottom structures, side shell and all longitudinal
bulkhead structures within 0.10D (D is vessel’s molded depth) from deck or bottom, respectively,
except for members and locations specified in 5C-5-A1/3.3.6 through 5C-5-A1/3.3.9 (see
5C-5-A1/7.5.2(d) below). For Zone A, stresses are to be calculated based on the wave-induced
loads specified in 5C-5-3/Table 1, as follows, except for the members and locations specified in
5C-5-A1/3.3.4, 5C-5-A1/3.3.5, 5C-5-A1/3.3.7 and 5C-5-A1/3.3.8 (see 5C-5-A1/7.5.2(d) below).
1 Calculate dynamic component of stresses for load cases L.C.1 through L.C.4, respectively.
2 Calculate two sets of stress ranges, one each for the following two pairs of combined loading
cases.
- L.C.1 and L.C.2, and
- L.C.3 and L.C.4
3 Use the greater of the stress ranges obtained by 2.

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7.5.2(b) Zone B. Zone B consists of side shell and all longitudinal bulkhead structures within the
region between 0.25D upward and 0.30D downward from the mid-depth and all transverse bulkhead
structures. The total stress ranges for Zone B may be calculated based on the wave-induced loads
specified in 5C-5-A1/Table 3 and 5C-5-3/Table 1, as follows, except for the members and locations
specified in 5C-5-A1/3.3.4, 5C-5-A1/3.3.5, 5C-5-A1/3.3.7 and 5C-5-A1/3.3.8 (see 5C-5-A1/7.5.2(d)
below).
1 Calculate dynamic component of stresses for load cases L.C.5 through L.C.10, L.C.F1
and L.C.F2, respectively.
2 Calculate four sets of stress ranges, one each for the following four pairs of combined
loading cases.
- L.C.5 and L.C.6,
- L.C.7 and L.C.8,
- L.C.9 and L.C.10, and
- L.C.F1 and L.C.F2
3 Use the greater of the stress ranges obtained by 2.
7.5.2(c) Transitional Zone. Transitional zone between A and B consists of side shell and all
longitudinal bulkhead structures between 0.1D and 0.25D (0.2D) from deck (bottom).
fR = fR(B) – [fR(B) – fR(A)] yu /0.15D
for upper transitional zone
fR = fR(B) – [fR(B) – fR(A)] yl/0.10D
for lower transitional zone
where
fR(A), fR(B) = the total stress ranges based on the combined load cases defined for Zone A
and Zone B, respectively
yu = vertical distance from 0.25D upward from the mid-depth upward to the
location considered
yl = vertical distance from 0.3D downward from the mid-depth downward to the
location considered
7.5.2(d) Hatch Related Members For members and locations specified in 5C-5-A1/3.3.4,
5C-5-A1/3.3.5 and 5C-5-A1/3.3.7, the total stress ranges are to be obtained in the same manner as
in 5C-5-A1/7.5.2(a) and 5C-5-A1/7.5.2 (b) for Zones A and B for the following six pairs of combined
loading cases:
- L.C.1 and L.C.2,
- L.C.3 and L.C.4,
- L.C.5 and L.C.6,
- L.C.7 and L.C.8,
- L.C.9 and L.C.10, and
- L.C.F1 and L.C.F2
7.5.2(e) Vessels with either Special Loading Patterns or Special Structural Configuration. For
vessels with either special loading patterns or special structural configurations/features, additional
load cases may be required for determining the stress range.

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Appendix 1 Guide for Fatigue Strength Assessment of Container Carriers 5C-5-A1

7.7 Primary Stress fd1 (2002)

fd1v and fd1h may be calculated by a simple beam approach. For assessing fatigue strength of side shell and
longitudinal bulkhead plating at welded connections, the value of wave-induced primary stress is to be
taken as that of maximum principal stresses at the location considered to account for the combined load
effects of the normal stresses and shear stresses. For calculating the value of fd1v for longitudinal deck
members, normal camber may be disregarded.
fd1w in way of hatch corners at strength deck, top of continuous hatch side coaming and lower deck, which
is effective for the hull girder strength and is located in line with the bottom of cross deck box beam,
within 0.22D below the strength deck at side, may be approximated by the following equation:
fd1w = kc fLWW N/cm2 (kgf/cm2, lbf/in2)
fLWW is defined in 5C-5-4/9.3 as specified for cargo space forward of engine room and for cargo space abaft
engine room. ω is to be used as a warping function at the location under consideration.
In a calculation of fLWW , Cw for the lower deck is to be used as 80% of that given for the strength deck in
5C-5-4/9.3.
kc is specified in 5C-5-A1/Table 3 and 5C-5-3/Table 1 for torsional moment with αs = 1.0.

7.9 Secondary Stress fd2i (1998)

When a 3D structural analysis is not available, the secondary bending stress ranges may be obtained from
an analytic calculation or experimental data with appropriate boundary conditions. Otherwise, the secondary
bending stresses may be calculated using the approximate equations given below. For the connections
specified in 5C-5-A1/3.3.1, the secondary bending stresses are low and may be ignored.
7.9.1 Double Bottom
The secondary longitudinal bending stress in double bottom panels may be obtained from the following
equation:

fd2bi = k1bk2bk3b pbei l2s rb/iG , N/cm2 (kgf/cm2, lbf/in2)

where
fd2bi = secondary longitudinal bending stress in the double bottom panel at the
intersection with the transverse bulkhead for the load case “i” considered.
For other intersections with transverse web/floor, fd2bi may be taken as zero.
k1b = 100 (100, 0.173) for bottom or inner bottom plating
= 91 (91, 0.157) for face plates, flanges and web plates of bottom and
inner bottom longitudinals
k2b = coefficient depending on apparent aspect ratio “ρb”, as given in 5C-5-A1/Table 4

ρb = 2.1(b/ls)(iG /iF)1/4
k3b = 1 – 3.9(z/b)2
z = the distance from vessel’s centerline to the double bottom longitudinal
member under consideration, in m (ft)
pbei = wave-induced external pressure on the bottom shell at the centerline and at
midpoint between watertight and mid-hold strength bulkheads of the hold
under consideration, for the load case “i” considered, as specified in 5C-5-3/9,
in N/cm2 (kgf/cm2, lbf/in2)
b = width of the double bottom panel (see 5C-5-A1/Figure 2), in m (ft)
ls = length between watertight bulkheads of the cargo hold being considered (see
5C-5-4/Figure 8), in m (ft)

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iG and iF = unit moments of inertia of the double bottom girders and floors, respectively
iG = IG /SG
iF = IF /SF
IG and IF = moments of inertia of an average girder and an average floor (see
5C-5-A1/Figure 2), respectively, including the effective width of
plating and stiffeners attached to the effective plating, in cm4 (in4)
SG and SF = average spacing of bottom girders and floors, respectively, in m (ft)
rb = distance between the horizontal neutral axis of the double bottom cross
section and the location of the structural element being considered
(bending lever arm – see 5C-5-A1/Figure 2), in cm (in.)
7.9.2 Double Sides
For double side structural members, the secondary longitudinal bending stress at the intersection
with the transverse strength bulkheads and web frames may be obtained from the following equation:
fd2si = k1sk2s psei h2rs/(iS iW)1/2 N/cm2 (kgf/cm2, lbf/in2)
where
fd2si = secondary longitudinal bending stress in the double side panel for the load
case “i” considered. fd2si at other intersections with transverse web/web frame
may be taken as zero.
k1s = 7.5 (7.5, 0.013) for side shell or longitudinal bulkhead plating
= 6.8 (6.8, 0.012) for face plates, flanges and web plates of side
longitudinals and longitudinal bulkhead stiffeners
k2s = [4ai(1 – y/h) – bi(1 – 2y/h)](y/h)
ai and bi = coefficients depending on apparent aspect ratio “ρs”, as given in
5C-5-A1/Table 5,
y = vertical distance from the lower end of “h” to the longitudinal member under
consideration, as shown in 5C-5-A1/Figure 2, in m (ft)
ρs = 0.48 (ls/h)(iW /iS)1/4
psei = wave-induced external pressure on the double side at the lower end of “h”
(but need not be lower than the upper turn of bilge) at the midpoint between
watertight and mid-hold strength bulkheads of hold under consideration, for
the load case “i” considered, as specified in 5C-5-3/9 in N/cm2 (kgf/cm2, lbf/in2)
h = height of the double side panel (see 5C-5-A1/Figure 2), in m (ft)
ls = length between watertight bulkheads of the cargo hold being considered (see
5C-5-4/Figure 8), in m (ft)
iS and iW = unit moments of inertia of the double side panel in the longitudinal and
vertical directions, respectively
iS = IS /SS
iW = IW /SW
IS and IW = moments of inertia of an average longitudinal stringer and an average web
frame, respectively, including the effective width of plating and stiffeners
attached to the effective plating, in cm4 (in4); where no stringers are fitted
within the double side height “h”, IS is to be calculated for a unit including
an average single longitudinal stiffener, as shown in 5C-5-A1/Figure 2

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Appendix 1 Guide for Fatigue Strength Assessment of Container Carriers 5C-5-A1

SS and SW = average spacing of longitudinal stringers and web plates, respectively, in m (ft);
where no stringers are fitted within the double side height “h”, SS is to be
taken as an average spacing between longitudinal stiffeners, as shown in
5C-5-A1/Figure 2
rs = distance between the vertical neutral axis of the double side cross section and
the location of structural element being considered (bending lever arm – see
5C-5-A1/Figure 2), in cm (in.)

7.11 Additional Secondary Stresses f d*2 and Tertiary Stresses fd3i (1998)

7.11.1 Calculation of f d*2

Where required, the additional secondary stresses acting at the flange of a longitudinal stiffener,
f d*2i may be approximated by

f d*2i = CtCy Mi /SM N/cm2 (kgf/cm2, lbf/in2)

where
Mi = pisl2/12 N-cm (kgf-cm, lbf-in) at the supported ends of
longitudinal without strut
= (cpi + co poi)sl2/12 N-cm (kgf-cm, lbf-in) at the supported ends and at the
strut connection of a longitudinal with strut
Where flat bar stiffeners or brackets are fitted, the bending moment, Mi, given above, may
be adjusted to the location of the brackets toe, i.e., Mx in 5C-5-4/Figure 7.
Where a longitudinal has remarkably different support stiffness at its two ends (e.g., a
longitudinal connected to a transverse bulkhead on one end), consideration is to be given
to the increase of bending moment at the joint.
pi = wave-induced local net pressure, N/cm2 (kgf/cm2, lbf/in2), for specified
location for the load case “i” at the midspan of the longitudinal considered
poi = wave-induced local net pressure, N/cm2 (kgf/cm2, lbf/in2), for specified
location for the load case “i” considered at the midspan of the longitudinal
connected to the other end of the strut
c = 0.650 at the supported ends
= -0.15 at the strut connection
co = 0.375 at the supported ends
= -0.375 at the strut connection
s = spacing of longitudinals/stiffeners, in cm (in.)
l = unsupported span of longitudinal/stiffener, in cm (in.), as shown in
5C-5-4/Figure 6
SM = net section modulus of the longitudinal with the associated effective plating,
in cm3 (in3), at the flange or point considered. The effective breadth, be, in
cm (in.), may be determined as shown in 5C-5-4/Figure 7.
Ct = correction factor for the combined bending and torsional stress induced by
lateral loads at the welded connection of the flat bar stiffener or bracket to
the flange of longitudinal, as shown in 5C-5-4/Figure/6.
= 1.0 + ar for unsymmetrical sections, fabricated or rolled
= 1.0 for tee and flat bars

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Cy = 0.656(d/y)4 ≥ 0.30 for side longitudinals, for y/d ≥ 0.9

= 1.0 for all other locations
d = draft, as defined in 3-1-1/9, in m (ft)
y = vertical distance from the base line to the side longitudinal under
consideration, in m (ft)
ar = CnCp SM/K

Cp = 31.2dw (e/l)2
e = horizontal distance between web centerline and shear center of the cross
section, including longitudinal and the effective plating
≈ dwbf2tf u/(2SM) cm (in.)
K = St. Venant torsion constant for the longitudinal’s cross section, excluding the
associated plating

= [bf tf3 + dw t w3 ]/3 cm4 (in4)

Cn = coefficient given in 5C-5-A1/Figure 3, as a function of ψ, for point (1)
shown in 5C-5-A2/Figure 1.
u = 1 – 2b1/bf

ψ = 0.31l(K/Γ)1/2
Γ = Warping constant

= mIyf d w2 + d w3 t w3 /36 cm6 (in6)

Iyf = tf bf3(1.0 + 3.0u2Aw /As)/12 cm4 (in4)
Aw = d w tw cm2 (in2)
As = net sectional area of the longitudinals, excluding the associated plating, in
cm2 (in2)
m = 1.0 – u(0.7 – 0.1dw /bf)
dw, tw, b1, bf, tf, all in cm (in.), are as defined in 5C-5-A2/Figure 1.
For general applications, ar need not be taken greater than 0.65 for a fabricated angle bar and 0.50
for a rolled section.
For connection as specified in 5C-5-A1/3.3.3, the wave-induced additional secondary stress f d∗2i
may be ignored.
7.11.2 Calculation of fd3i
For welded joints of a stiffened plate panel, fd3i may be determined based on the wave-induced
local loads as specified in 5C-5-A1/7.11.1 above, using the approximate equations given below.
For direct calculation, non-linear effect and membrane stresses in the plate may be considered.
For plating subjected to lateral load, fd3i in the longitudinal direction is determined as:
fd3i = 0.182pi(s/tn)2 N/cm2 (kgf/cm2, lbf/in2)
where
pi = wave-induced local net pressure for the load case “i” considered, in N/cm2
(kgf/cm2, lbf/in2)
s = spacing of longitudinal stiffeners, in mm (in.)
tn = net thickness of plate, in mm (in.)

800 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 1 Guide for Fatigue Strength Assessment of Container Carriers 5C-5-A1

7.13 Calculation of Stress Range for Side Frame and Vertical Stiffener on Longitudinal
Bulkhead (1998)
For fatigue strength assessment, the stress range acting at the flange of a side frame and vertical stiffener
on longitudinal bulkhead may be obtained from the following equation:

fR = cf cw( | f d*2i | + | f d*2 j | ) N/cm2 (kgf/cm2, lbf/in2)

The values of f d*2i and f d*2 j may both be approximated by

f d*2i = CtMi /SM N/cm2 (kgf/cm2, lbf/in2)

where
Mi = pisl2/12 N-cm (kgf-cm, lbf-in)
at the supported ends of frame without strut
= (cpi + copoi)sl2/12 N-cm (kgf-cm, lbf-in)
at the supported ends and at the strut connection of a frame with strut
Where flat bar stiffeners or brackets are fitted, the bending moment, Mi, given above, may be adjusted to
the location of the bracket toe, i.e., Mx in 5C-5-4/Figure 7.
pi = wave-induced local net pressure, in N/cm2 (kgf/cm2, lbf/in2), for specified location for
load case “i” at the midspan of the frame considered. The local net pressure is to be
taken as an average value of that calculated at lower and upper ends of the span.
poi = wave-induced local net pressure, in N/cm2 (kgf/cm2, lbf/in2), for specified location for
load case “i” at the midspan of the stiffener connected to the other end of the strut
c = 0.650 at the supported ends
= -0.125 at the strut connection
co = 0.375 at the supported ends
= -0.375 at the strut connection
s = spacing of frame/stiffener, in cm (in.)
l = unsupported span of frame/stiffener, in cm (in.)
SM = net section modulus of the frame with the associated effective plating, in cm3 (in3), at
the flange or point considered. The effective breadth, be, in cm (in.), may be
determined as shown in 5C-5-4/Figure 7.
cf and cw are as defined in 5C-5-A1/7.5.1 and Ct is as defined in 5C-5-A1/7.11.1.

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Appendix 1 Guide for Fatigue Strength Assessment of Container Carriers 5C-5-A1

FIGURE 2
Dimensions of Double Bottom and Double Side (1998)
Mid-Hold
W. T. Srength Bhd Strength Bhd W. T. Srength Bhd

CARGO HOLD

rS

SS

SF

Strength Deck

2nd deck

II
h

SS y b/2

SG

rb
L
C

b/2
h h
h b/2

b/2

L
C L
C L
C

Type I when one or more longitudinal stringers (decks) are fitted in double-side structure
Type II when no longitudinal stringers are fitted in double-side structure

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 1 Guide for Fatigue Strength Assessment of Container Carriers 5C-5-A1

FIGURE 3
Cn = Cn (ψ) (1998)

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 1 Guide for Fatigue Strength Assessment of Container Carriers 5C-5-A1

TABLE 3
Combined Load Cases for Container Carriers (1998)
Fatigue Assement (1)
L.C. F1 L.C. F2 Load Cases F1 and F2 for Fatigue
A HULL GIRDER LOADS (2) Load Cases F1 and F2 For Fatique
Vertical B.M. (3) kc Sag (−) 0.4 Hog (+) 0.4
Vertical S.F. kc (+) 0.4 (−) 0.4
Horizontal B.M. kc Stbd Tens (-) 1.0 Port Tens (+) 1.0
Horizontal S.F. kc (+) 1.0 (−) 1.0
Torsional Mt. (4) kc (−) 0.55 αs (+) 0.55 αs
B EXTERNAL PRESSURE
kc 0.5 1.0
kf0 −1.0 1.0
LOAD CASE F1
C CONTAINER CARGO LOAD Heading 60 Deg.
kc 1.0 0.5 Heave Down
Pitch Bow Down
cV 0.7 −0.7 Roll STBD
Down
cL Fwd Bhd 0.7 Fwd Bhd 0.0 Draft Full
Aft Bhd 0.0 Aft Bhd −0.7 Wave VBM Sag
cT Port Wall 0.0 Port Wall −0.7
Stbd Wall 0.7 Stbd Wall 0.0
Cφ, Pitch −0.7 0.7
Cθ, Roll 0.7 −0.7
D INTERNAL BALLAST TANK PRESSURE
kc 1.0 0.5
wv 0.4 −0.4
wl Fwd Bhd 0.2 Fwd Bhd −0.2 LOAD CASE F2
Aft Bhd −0.2 Aft Bhd 0.2 Heading 60 Deg.
Heave Up
wt Port Wall −0.4 Port Wall 0.4 Pitch Bow Up
Stbd Wall 0.4 Stbd Wall −0.4 Roll STBD Up
Draft Full
Cφ, Pitch −0.7 0.7
Wave VBM Hog
Cθ, Roll 0.7 −0.7
E REFERENCE WAVE HEADING AND POSITION Light Cargo
Heading Angle 60 60 7 mt per TEU as a maximum

Heave Down Up
Heavy Cargo
Pitch Bow Down Bow Up 14 mt per TEU as a minimum

Roll Stbd Down Stbd Up

Ballast, S.G. = 1.025
Draft 1 1

1 ku = 1.0 for all load components.

2 Boundary forces are to be applied to produce the above specified hull girder bending moment at the middle of the structural
model, and specified hull girder shear force at one end of the middle hold of the model. The sign convention for the shear
force corresponds to the forward end of middle hold. The specified torsional moment is to be produced at the aft bulkhead of
the middle hold.
3 The following still water bending moment (SWBM) is to be used for structural analysis.
L.C. F1: Maximum sagging SWBM.
L.C. F2: Maximum hogging SWBM.
4 (1999) αs is to be obtained by the following equation:
αs = (Tm + Ts)/Tm
where
Tm = nominal wave-induced torsional moment amidships, in kN-m (tf-m, Ltf-ft), as defined in 5C-5-3/5.1.5(a)
Ts = still-water torsionl moment amidships, in kN-m (tf-m, Ltf-ft), as defined in 5C-5-3/3.1

804 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 1 Guide for Fatigue Strength Assessment of Container Carriers 5C-5-A1

TABLE 4
Coefficient k3b for Double Bottom Panels
ρb 1.0 1.2 1.4 1.6 1.8 2.0 ≥ 2.2
k2b 700 791 844 876 896 908 915

TABLE 5
Coefficient ai and bi for Double Bottom Panels
ρs 0.7 0.8 0.9 1.0 1.2 1.5 ≥ 2.0
At W/T ai 566 464 389 333 254 183 120
Strength Bhd bi 166 150 136 123 101 74 45
At Mid-hold ai 508 417 350 299 228 164 108
Strength Bhd bi 150 136 123 111 91 67 40

9 Determination of Stress Concentration Factors (SCFs) (1998)

9.1 General
This section contains information on stress concentration factors (SCFs) to be considered in the fatigue
assessment.
Where, for a particular example shown, no specific value of SCF is given when one is called for, it indicates
that a finite element analysis is needed. When the fine mesh finite element approach is used, additional
information on calculations of stress concentration factors and the selection of compatible S-N data is
given in 5C-5-A1/11.

9.3 Sample Stress Concentration Factors (SCFs) (1 July 2001)

9.3.1 Cut-outs (Slots) for Longitudinal (1998)
SCFs, fatigue classifications and peak stress ranges may be determined in accordance with
5C-5-A1/Table 6 and 5C-5-A1/Figure 4.

TABLE 6
Ks (SCF) Values
Ks (SCF)
Configuration Unsymmetrical Flange Symmetrical Flange
Location [1] [2] [3] [1] [2] [3]
Single-sided Support 2.0 2.1 — 1.8 1.9 —
Single-sided Support with F.B. Stiffener 1.9 2.0 — 1.7 1.8 —
Double-sided Support 2.4 2.6 1.9 2.4 2.4 1.8
Double-sided Support with F.B. Stiffener 2.3 2.5 1.8 2.3 2.3 1.7

Notes: a The value of Ks is given based on nominal shear stresses near the locations under consideration.
b Fatigue classification
Locations [1] and [2]: Class C or B as indicated in 5C-5-A1/Table 1
Location [3]: Class F

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Appendix 1 Guide for Fatigue Strength Assessment of Container Carriers 5C-5-A1

TABLE 6 (continued)
Ks (SCF) Values
c The peak stress range is to be obtained from the following equations:
1 For locations [1] and [2] (1999)
fRI = cf [Ksifsi + fni]
where
cf = 0.95
fsi = fsc + αi fswi, fsi ≥ fsc
αi = 1.8 for single-sided support
= 1.0 for double-sided support
fni = normal stress range in the web plate
fswi = shear stress range in the web plate
= Fi/Aw
Fi is the calculated web shear force range at the location considered. Aw is the area of web.
fsc = shear stress range in the support (lug or collar plate)
= CyP/(Ac + As)
Cy is as defined in 5C-5-A1/7.11.1.
P = s l po
po = fluctuating lateral pressure
Ac = sectional area of the support or of both supports for double-sided support
As = sectional area of the flat bar stiffener, if any
Ksi = SCFs given above
s = spacing of longitudinal/stiffener
l = spacing of transverses

2 For location [3]

2
fR3 = cf [f n 3 + (Ks fs2)2]1/2
where
cf = 0.95
fn3 = normal stress range at location [3]
fs2 = shear stress range as defined in 1 above near location [3].
Ks = SCFs given above

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Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 1 Guide for Fatigue Strength Assessment of Container Carriers 5C-5-A1

FIGURE 4
Cut-outs (Slots) For Longitudinal (1998)

Double - Sided Support

Web Plate
Class C or B F.B. Stiffener

[2] [2]
[1]
[1]
F1 F2 F1 F2
R R f3
f3
[1] [1]
[3] [3]
f s1 f s2 f s1 f s2

P R ≥ 35mm P

Web Plate
Class C or B F.B. Stiffener

[2] [2]
[1] [1]
F1 F2 F1 F2
R R R f3
f3
[1] [1] [3] [3]
f s1 f s2 f s2
f s1

R ≥ 35mm
P P

Single - Sided Support

Web Plate
Class C or B F.B. Stiffener

[2] [2] [1] [2]

F1 F2 F1 F2
R R R R
f3 f3
[1]
f s2 [3] f s1 f s1

R ≥ 35mm
P P

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Appendix 1 Guide for Fatigue Strength Assessment of Container Carriers 5C-5-A1

9.3.2 Flat Bar Stiffeners for Longitudinals (1999)

9.3.2(a) For assessing fatigue life of a flat bar stiffener at location [1] or [2] as shown in
5C-5-A1/Figure 5, the peak stress range is to be obtained from the following equations:
fRi = [(αi fs)2 + fL2 ]1/2 (i = 1 or 2)
where
fs = nominal stress range in the flat bar stiffener.
= cf CyP/(As + Ac)
P, As, Ac, cf as defined in 5C-5-A1/9.3.1 and Cy in 5-3-A1/7.11.1. For flat bar stiffeners with soft-
toed brackets, the brackets may be included in the calculation of As.
fLi = stress range in the longitudinal at location i (i = 1 or 2), as specified in
5C-5-A1/7.5
αi = stress concentration factor at location i (i = 1 or 2) accounting for
misalignment and local distortion.
At location [1]
For flat bar stiffener without brackets
α1 = 1.50 for double-sided support connection
= 2.00 for single-sided support connection
For flat bar stiffener with brackets
α1 = 1.00 for double-sided support connection
= 1.25 for single-sided support connection
At location [2]
For flat bar stiffener without brackets
α2 = 1.25 for single or double-sided support connection
For flat bar stiffener with brackets
α2 = 1.00 for single or double-sided support connection
9.3.2(b) For assessing the fatigue life of the weld throat as shown in 5C-5-A1/Table 1, Class W,
the peak stress range fR at the weld may be obtained from the following equation:
fR = 1.25fsAs/Asw
where
Asw = sectional area of the weld throat. Brackets may be included in the calculation
of Asw
fs and As are as defined in 5C-5-A1/9.3.2(a) above.
9.3.2(c) To assess the fatigue life of the longitudinal, the fatigue classification given in
5C-5-A1/Table 1 for the longitudinal as the only load carrying member is to be considered.
Alternatively, the fatigue classification shown in 5C-5-A1/Figure 5 in conjunction with the combined
stress effects, fR, may be used. In calculation of fR, the αi may be taken as 1.25 for both locations
[1] and [2].

808 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 1 Guide for Fatigue Strength Assessment of Container Carriers 5C-5-A1

FIGURE 5
Fatigue Classification for Longitudinals in way of Flat Bar Stiffener

45° 45°

* *

* may be used in the calculation

of As and Asw.

Web Plate
Web Plate

Flat Bar

Flat Bar
[1]
Class E
fL1 [1] [2]

fs
[2] Class E Class E
fs

[1] Class F
Class F

fL1 fL2 fL1 fL2

Longitudinal Longitudinal
Shell Plating Shell Plating

P P

F.B. without Brackets F.B. with Brackets

9.5 Hatch Corner (1998)

9.5.1 Side Hatch Corners
The peak stress range, fR, for hatch corners at the strength deck, the top of the continuous hatch
side coaming and the lower deck which is effective for the hull girder strength and is located in
line with the bottom of cross deck box beam, within 0.22D below the strength deck at side may be
approximated by the following equation:
fR = cf [Ks1cL1(fRG1 + fRL1) + Ks2cL2(fRG2 + fRL2)] N/cm2 (kgf/cm2, lbf/in2)
where
fRG1 = global dynamic longitudinal stress range at the inboard edge of the strength
deck plating of hull girder section under consideration clear of hatch corner,
in N/cm2 (kgf/cm2, lbf/in2)
= |(fd1vi – fd1vj) + (fd1hi – fd1hj) + (fd1wi – fd1wj)|
fRG2 = bending stress range in connection with hull girder twist induced by torsion
in cross deck structure in transverse direction, in N/cm2 (kgf/cm2, lbf/in2).
fRG2 may be taken as zero in Stations A, B, C, F′ and G in 5C-5-4/Figure 5.
= |fd1ci – fd1cj|
fRL1 = secondary dynamic longitudinal stress range induced by external pressure at
the inboard edge of the strength deck plating of hull girder section under
consideration clear of hatch corner, in N/cm2 (kgf/cm2, lbf/in2)
= cw (|fd2si – fd2sj|)

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Appendix 1 Guide for Fatigue Strength Assessment of Container Carriers 5C-5-A1

fRL2 = secondary stress range on the cross deck structure in transverse direction due
to dynamic container load in longitudinal direction, in N/cm2 (kgf/cm2, lbf/in2).
fRL2 may be taken as zero in Stations A, B, C, F′ and G in 5C-5-4/Figure 5.
= cw(|fd2ci – fd2cj|)
cw = 0.75
cf, cw, fd1vi, fd1vj, fd1hi, fd1hj, fd1wi and fd1wj are as defined in 5C-5-A1/7.5.1 and 5C-5-A1/7.7.
Ks1 and Ks2 are stress concentration factors for the hatch corners considered and can be obtained
by a direct finite element analysis. When a direct analysis is not available, these may be obtained
from the following equations, but not to be taken less than 1.0:
Ks1 = αl1ctαt1αcαsks1

Ks2 = αl2αgαctαt2ks2
where
ks1 = nominal stress concentration factor in longitudinal direction, as given in a
table below
ks2 = nominal stress concentration factor in transverse direction, as given in a table
below
ct = 0.8 for locations where coaming top terminated
= 1.0 for other locations
αl1 = location adjustment factor
= 1.0 for typical hatch corners of the strength deck and the lower deck in
the midship region, e.g., Stations D and D′ as in 5C-5-4/Figure 5
= 1.2 for hatch corners of the strength deck and the lower deck at Stations
E and F as in 5C-5-4/Figure 5 where there is a change in width of
the hatch opening
= 1.55 for hatch corners of the strength deck and the lower deck at Stations
A, B, C, F′ and G, as in 5C-5-4/Figure 5
= 0.9 for a hatch corner at the top of a continuous hatch side coaming
αl2 = 1.0 for a hatch corner at the strength deck and the lower deck
= 0.9 for a hatch corner at the top of a continuous hatch side coaming
αc = adjustment factor for cutout at hatch corners
= 1.0 for shapes without cutout
= 1 – 0.04(c/R)3/2 for circular shapes with a cutout
= [1 – 0.04(c/rd)3/2] for double curvature shapes with a cutout
= [1 – 0.04(c/R1)3/2] for elliptical shapes with a cutout

αs = adjustment factor for contour curvature

= 1.0 for circular shapes
= 0.33 [1 + 2(rs1/rd) + 0.1(rd /rs1)2] for double curvature shapes
= 0.33 [1 + 2(R2/R1) + 0.1(R1/R2)2] for elliptical shapes

810 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 1 Guide for Fatigue Strength Assessment of Container Carriers 5C-5-A1

αg = 0.9 for hatch corners at Station E and F where there is a change in width
of the hatch opening by an offset of one container row.
= 0.8 for hatch corners at Station E and F where there is a change in width
of the hatch opening by an offset of two container rows or more
= 1.0 for other hatch corners
αct = 1.0 for shapes without cutout
= 0.5 for shapes with cutout
αt1 = (ts /ti) 1/2

αt2 = 6.0/[5.0 + (ti /tc)], but not less than 0.85

αt1 or αt2 is to be taken as 1.0 where longitudinal or transverse extent of the reinforced
plate thickness in way of the hatch corner is less than that required in 5C-5-A1/9.5.3
below, as shown in 5C-5-A1/Figure 6.
rs1 = R for circular shapes in 5C-5-A1/Figure 7, in mm (in.)

= [3R1/(R1 – R2) + cos θ]re2 /[3.816 + 2.879R2/(R1 – R2)]

for double curvature shapes in 5C-5-A1/Figure 8, in mm (in.)
= R2 for elliptical shapes in 5C-5-A1/Figure 9, in mm (in.)
rs2 = R for circular shapes in 5C-5-A1/Figure 7, in mm (in.)
= R2 for double curvature shapes in 5C-5-A1/Figure 8, in mm (in.)
= R22/R1 for elliptical shapes in 5C-5-A1/Figure 9, in mm (in.)

rd = (0.753 – 0.72R2/R1)[R1/(R1 – R2) + cos θ]re1

ts = net plate thickness of the strength deck, hatch side coaming top or lower
deck clear of the hatch corner under consideration, in mm (in.)
tc = net plate thickness of the cross deck, hatch end coaming top or bottom of
cross box beam clear of the hatch corner under consideration, in mm (in.)
ti = net plate thickness of the strength deck, hatch coaming top or lower deck in
way of the hatch corner under consideration, in mm (in.).
R, R1 and R2 for each shape are as shown in 5C-5-A1/Figures 7, 8 and 9.

θ for double curvature shapes is defined in 5C-5-A1/Figure 8.

re1 and re2 are also defined for double curvature shapes in 5C-5-A1/9.5.3 below.

ks1
rs1 / w1 0.1 0.2 0.3 0.4 0.5
ks1 1.945 1.89 1.835 1.78 1.725

ks2
rs2 / w2 0.1 0.2 0.3 0.4 0.5
ks2 2.35 2.20 2.05 1.90 1.75

Note: ks1 and k s2 may be obtained by interpolation for intermediate values of rs1/w1 or rs2/ w2.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 811
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 1 Guide for Fatigue Strength Assessment of Container Carriers 5C-5-A1

where
w1 = width of the cross deck under consideration, in mm (in.), for hatch corners of
the strength deck and lower deck at Stations D, D′, E and F
= 100b1 for SI or MKS Units, (1.2b1 for U.S. Units) for hatch corners of the
strength deck and lower deck at Stations A, B, C, F′ and G
= width of the coaming top for the continuous hatch side coaming, in mm (in.)
w2 = width of the cross deck under consideration, in mm (in.), for strength deck
and lower deck
= width of the coaming top for the hatch end coaming, in mm (in.)
b1 = width of the hatch opening under consideration, in m (ft)
Ks1 and Ks2 for hatch corners with configurations other than that specified in this section are to be
determined from fine mesh 3D and 2D finite element analysis.
The angle φ in degrees along the hatch corner contour is defined as shown in 5C-5-A1/Figures 7, 8
and 9 and cL1 and cL2 at a given φ may be obtained by the following equations. For determining the
maximum fR, cL1 and cL2 are to be calculated at least for 5 locations, i.e., at φ = φ1, φ2 and three
intermediate angles for each pair of the combined load cases considered. Alternatively, the
maximum fR may be searched by a computer program provided in the SafeHull software package.
for circular shapes, 25 ≤ φ ≤ 55
cL1 = 1 – 0.00045(φ – 25)2

cL2 = 0.8 – 0.0004(φ – 55)2

for double curvature shapes, φ1 ≤ φ ≤ φ2
cL1 = [1.0 – 0.02(φ – φ1)]/[1 – 0.015(φ – φ1) + 0.00014(φ – φ1)2] for θ < 55
= [1.0 – 0.026(φ – φ1)]/[1 – 0.03(φ – φ1) + 0.0012(φ – φ1)2] for θ ≥ 55
cL2 = 0.8/[1.1 + 0.035(φ – φ2) + 0.003(φ – φ2)2]
where
φ1 = μ(95 – 70rs1/rd)
φ2 = 95/(0.6 + rs1/rd)

μ = 0.165(θ – 25)1/2 for θ < 55

= 1.0 for θ ≥ 55
for elliptical shapes, φ1 ≤ φ ≤ φ2
cL1 = 1 – 0.00004(φ – φ1)-3

cL2 = 0.8/[1 + 0.0036(φ – φ2)2]

where
φ1 = 95 – 70R2/R1
φ2 = 88/(0.6 + R2/R1)
The peak stress range, fR, is to be obtained through calculations of cL1 and cL2 at each φ along a
hatch corner.

812 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 1 Guide for Fatigue Strength Assessment of Container Carriers 5C-5-A1

The formulas for double curvature shapes and elliptical shapes may be applicable to the following
range:
0.3 ≤ R2/R1 ≤ 0.6 and 45° ≤ θ ≤ 70° for double curvature shapes

At Stations A, B, C, F′ and G, the upper limit of θ may be increased to 80°.

For hatch coaming top and longitudinal deck girders, R2/R1 may be reduced to 0.15.

0.3 ≤ R2/R1 ≤ 0.9 for elliptical shapes

fd1ci, fd2si and fd2ci for the load case i may be obtained from the following equations:
9.5.1(a) Calculation of fd1ci (2002)

fd1ci = ckcM1/SMc N/cm2 (kgf/cm2, lbf/in2)

where
SMc = net section modulus of the cross deck box beam clear of the hatch corner under
consideration with respect to the vertical axis z (5C-5-4/Figure 4), in cm3 (in3)
c = 1.0 for strength deck and hatch coaming top
= 0.8 for lower deck
M1 is as defined in 5C-5-4/17.7.4. In calculation of M1, Ts is to be taken as zero and z is to be
taken as a distance from the vessel’s centerline to a section clear of hatch corner but need not be
more than b0/2 at each station, as shown in 5C-5-4/Figure 5.
fd1ci may be taken as zero at Stations A, B, C, F′ and G in 5C-5-4/Figure 5.

kc is specified in 5C-5-A1/Table 3 and 5C-5-3/Table 1 for torsional moment with αs = 1.0..

9.5.1(b) Calculation of fd2si
fd2si = Ms/SM N/cm2 (kgf/cm2, lbf/in2)
where
Ms = secondary bending moment due to external water pressure at watertight or
mid-hold strength bulkhead, in N-m (kgf-cm, lbf-in)

= kpsi l o2 h
k = 1000 (1000, 269)
psi = wave-induced external pressure, kN/m2 (tf/m2, Ltf/ft2), at the lower end of h
(but need not be lower than the upper turn of bilge) at the midpoint of the
hatch opening under consideration.
lo = length of the hatch opening under consideration, in m (ft)
h is as defined in 5C-5-A1/7.9.2.
SM is as defined in 5C-5-4/17.5.2.
9.5.1(c) Calculation of fd2ci

fd2ci = M/SMc N/cm2 (kgf/cm2, lbf/in2)

where
M = secondary bending moment on the cross deck structure due to dynamic
container load in longitudinal direction, in N-cm (kgf-cm, lbf-in)
= KC2[0.5Qd1 + 0.25Qd2 n/(n + 1)]b1105

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 813
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 1 Guide for Fatigue Strength Assessment of Container Carriers 5C-5-A1

K = 0.17 (0.17, 0.046)

Qd1 = total dynamic container load in longitudinal direction on cross deck box
beam (above the bottom of cross deck box beam), in kN (tf, Ltf)
= m1m2(1 – h5/h4) Fdl1
Qd2 = total dynamic container load in longitudinal direction on transverse
bulkhead, (below the bottom of cross deck box beam), in kN (tf, Ltf)
= m1m2(h5/h4) Fdl 2
m1 = tier number of container stacks in the cargo hold under consideration
m2 = row number of container stacks in the cargo hold under consideration
h4 = m1hC
h5 = vertical distance between the bottom of the cargo hold under consideration
and the bottom of cross deck box beam at center line, in m (ft)
Fdl1 = dynamic longitudinal container force Fdl, as specified in 5C-5-3/5.5.2(b), with
W of the maximum design container weight at a vertical height 0.5(h4 + h5),
measured from inner bottom
Fdl2 = dynamic longitudinal container force Fdl, as specified in 5C-5-3/5.5.2(b),
with W of the maximum design container weight at a vertical height 0.5h5,
measured from inner bottom
W, C2, n and hC are as defined in 5C-5-4/17.5.3.
b1 is as defined in 5C-5-4/17.7.4, but need not be taken as greater than b0 at each station in
5C-5-4/Figure 5.
fd2ci may be taken as zero at Stations A, B, C, F′ and G in 5C-5-4/Figure 5.
SMc is as defined in 5C-5-A1/9.5.1(a) above.

9.5.2 Hatch Corners at the End Connections of Longitudinal Deck Girder

The total stress range, fR, for hatch corners at the connection of longitudinal deck girder with cross
deck box beam may be approximated by the following equation:
fR = cf[(αiKd1(fRG1 + fRL1) + Kd2 fRG2] N/cm2 (kgf/cm2, lbf/in2)
where
fRG1 = wave-induced stress range by hull girder vertical and horizontal bending
moments at the longitudinal deck girder of hull girder section, in N/cm2
(kgf/cm2, lbf/in2)
= |(fd1vi – fd1vj) + (fd1hi – fd1hj)|
fRG2 = wave-induced stress range by hull girder torsional moment at the connection
of the longitudinal deck girder with the cross deck box beam, in N/cm2
(kgf/cm2, lbf/in2)
= |fd1di – fd1dj|
fRL1 = secondary dynamic stress range on the longitudinal deck girder due to on-
deck container load in vertical direction, in N/cm2 (kgf/cm2, lbf/in2)
= cw( |fd2di – fd2dj| )
cw = 0.75

814 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 1 Guide for Fatigue Strength Assessment of Container Carriers 5C-5-A1

αi = 1.0 for symmetrical section of the longitudinal deck girder about its
vertical neutral axis
= 1.25 for unsymmetrical section of the longitudinal deck girder about its
vertical neutral axis
cf is as defined in 5C-5-A1/7.5.1.
Kd1 and Kd2 may be obtained from the following equations, but not to be taken less than 1.0:
Kd1 = 1.0

Kd2 = α1αskd
where
kd = nominal stress concentration factor as given in a table below
αs = 1.0 for circular shapes
= 0.33[1 + 2(rs1/rd) + 0.1(rd /rs1)2] for double curvature shapes
= 0.33[1 + 2(R2/R1) + 0.1(R1/R2)2] for elliptical shapes

αt = (td/ti)1/2
αt is to be taken as 1.0 where longitudinal or transverse extent of the reinforced plate thickness in
way of the hatch corner is less than that in 5C-5-A1/9.5.3 below, as shown in 5C-5-A1/Figure 10.
td = flange net plate thickness of the longitudinal deck girder clear of the hatch
corner under consideration, in mm (in.)
ti = net plate thickness at the end connection of the longitudinal deck girder
under consideration, in mm (in.).
R, R1 and R2 for each shape are as shown in 5C-5-A1/Figures 7, 8 and 9.

θ for double curvature shapes is defined in 5C-5-A1/Figure 8.

rs1 and rd are as defined for double curvature shapes in 5C-5-A1/9.5.1, above.
re1 and re2 are as defined for double curvature shapes in 5C-5-A1/9.5.3, below.

kd
rs1 / wd 0.1 0.2 0.3 0.4 0.5
kd 2.35 2.20 2.05 1.90 1.75

Note: kd may be obtained by interpolation for intermediate values of rs1 / wd.

where
wd = width of the longitudinal deck girder, in mm (in.)
fd1vi, fd1hi, fd1di and fd2di for the load case i may be obtained from the following equations:
9.5.2(a) Calculation of fd1vi
fd1vi = cHoMwE /SM N/cm2 (kgf/cm2, lbf/in2)
where
c = 1000 (1000, 2240)
Ho = effectiveness of longitudinal deck structure, as specified in 3-2-1/17.3

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 815
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 1 Guide for Fatigue Strength Assessment of Container Carriers 5C-5-A1

MwE = wave-induced bending moment at the section under consideration, in a

condition as specified in 5C-5-3/Table 1 and 5C-5-A1/Table 3, in kN-m
(tf-m, Ltf-ft)
= kukc fMVMw
SM = net hull girder vertical section modulus at the section under consideration,
cm2-m (in2-ft)
= I/y
I = moment of inertia of hull girder section under consideration about the
horizontal neutral axis, in cm2-m2 (in2-ft2)
y = vertical distance from the horizontal neutral axis of the hull girder section to
the point under consideration, m (ft)
Mw = the nominal wave-induced vertical bending moment, as defined in 5C-5-3/5.1.1,
with kw = k 01 / 2 for either hogging or sagging condition, as specified in
5C-5-3/Table 1 and 5C-5-A1/Table 3, in kN-m (tf-m, Ltf-m)
ku and kc are specified in 5C-5-A1/Table 3 and 5C-5-3/Table 1 for hull girder vertical bending moment.
fMV is as shown in 5C-5-3/Figure 2.
9.5.2(b) Calculation of fd1hi

fd1hi = cHoMHE/SMH N/cm2 (kgf/cm2, lbf/in2)

where
c = 1000 (1000, 2240)
Ho = effectiveness of longitudinal deck structure, as specified in 3-2-1/17.3
MHE = effective wave-induced horizontal bending moment at the section under
consideration, in a condition as specified in 5C-5-3/Table 1 and
5C-5-A1/Table 3, in kN-m (tf-m, Ltf-ft)
= kukcmhMH
SMH = net hull girder horizontal section modulus at the section under consideration,
in cm2-m (in2-ft)
= IH /z
IH = moment of inertia of hull girder section under consideration about the
vessel’s centerline, in cm2-m2 (in2-ft2)
z = horizontal distance from the vessel’s centerline to the vertical neutral axis
(z axis of section D-D in item b of 5C-5-A1/Table 2) of the longitudinal side
deck girder, in m (ft)
fd1hi for the centerline deck girder may be taken zero.
ku and kc are specified in 5C-5-A1/Table 3 and 5C-5-3/Table 1 for hull girder horizontal bending
moment.
MH is as defined in 5C-5-3/5.1.3 and mh is as shown in 5C-5-3/Figure 4.
9.5.2(c) Calculation of fd1di (2002)
fd1di = MD /SMh N/cm2 (kgf/cm2, lbf/in2)

816 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 1 Guide for Fatigue Strength Assessment of Container Carriers 5C-5-A1

where

MD = kc1kcC1TM L20 ωM105/(c2b0αMΓM) N-cm (kgf-cm, lbf-in)

k = 1.0 (1.0, 0.269)
SMh = net section modulus of the longitudinal deck girder under consideration about
its vertical neutral axis (z axis of section D-D in item b of 5C-5-A1/Table 2),
in cm3 (in3)
cs = 0.53 for centerline deck girder
= 0.42 for two side deck girders
∗
c2 = c3b0/ I CB + l0/Ig
c3 = 0.75 for centerline deck girder
= 0.425 for two side deck girders
l0 = length of the hatch opening amidships, in m (ft)
∗
I CB = average net moment of inertia of the cross deck box beam at the vessel’s
centerline, in m4 (ft4), fore and aft of the hatch opening amidships with
respect to vertical axis, z.
Ig = net moment of inertia of the longitudinal deck girder amidships about its
vertical neutral axis (z axis of section D-D in 5C-5-A1/Table 2b), in cm4 (in4)
TM, L0, ωM, αM, ΓM and b0 are as defined in 5C-5-4/7 and C1 is as defined in 5C-5-4/17.7.2. kc is
specified in 5C-5-3/Table 1 and 5C-5-A1/Table 3 for torsional moment with αs = 1.0.
For the longitudinal deck girders abaft the engine room, L0 may be taken as L0′ defined in
5C-5-4/9.3.2.
9.5.2(d) Calculation of fd2di
fd2di = M/SMV N/cm2 (kgf/cm2, lbf/in2)
where
M = secondary bending moment on the longitudinal deck girder due to dynamic
container load on deck in vertical direction, in N-cm (kgf-cm, lbf-in)
= k c md1md2Fdvl·105
k = 1.0 (1.0, 0.269)
c = 0.042 for centerline deck girder
= 0.028 for two side deck girders
md1 = tier number of 20 ft container stacks on deck
md2 = row number of 20 ft container stacks on deck
Fdv = dynamic vertical container force as specified in 5C-5-3/5.5.2 with W of the
maximum design 20 ft container weight on deck and W not to be taken less
than 137.3 kN (14 tf, 13.8 Ltf)
SMv = net section modulus of the longitudinal deck girder under consideration about
its horizontal axis (y axis of section D-D in 5C-5-A1/Table 2b), in cm3 (in3)
l is as defined in 5C-5-A1/7.9.2.
For calculation of Cv in 5C-5-3/5.5.1(c), z, defined in 5C-5-A1/9.5.2(b) above, may be used.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 817
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 1 Guide for Fatigue Strength Assessment of Container Carriers 5C-5-A1

9.5.3 Extent of Reinforced Plate Thickness at Hatch Corners

Where plating of increased thickness is inserted at hatch corners, the extent of the inserted plate,
as shown in 5C-5-A1/Figure 6 and 5C-5-A1/Figure 10, is to be generally not less than that obtained
from the following:
li = 1.75re1 mm (in.)
bi = 1.75re2 mm (in.)
bd = 1.1re2 mm (in.)
for a cut-out radius type,
li1 = 1.75re1 mm (in.)

li2 = 1.0re1 mm (in.)

bi = 2.5re2 mm (in.)
bd = 1.25re2 mm (in.)
where
re1 = R for circular shapes in 5C-5-A1/Figure 7, in mm
(in.)
= R2 + (R1 – R2)cos θ for double curvature shapes in 5C-5-A1/Figure 8, in
mm (in.)
= (R1 + R2)/2 for elliptical shapes in 5C-5-A1/Figure 9, in mm
(in.)
re2 = R for circular shapes in 5C-5-A1/Figure 7, in mm
(in.)
= R1 – (R1 – R2)sin θ for double curvature shapes in 5C-5-A1/Figure 8, in
mm (in.)
= R2 for elliptical shapes in 5C-5-A1/Figure 9, in mm
(in.)
At welding joints of the inserted plates to the adjacent plates, a suitable transition taper is to be
provided and the fatigue assessment at these joints may be approximated by the following:
fR = cf Kt fs N/cm2 (kgf/cm2, lbf/in2)
where
fs = nominal stress range at the joint under consideration
= fRG1 + fRL1 for side longitudinal deck box, as specified in
5C-5-A1/9.5.1, in N/ cm2 (kgf/cm2, lbf/in2)
= fRG2 + fRL2 for cross deck box beam, as specified in 5C-5-A1/9.5.1,
in N/cm2 (kgf/cm2, lbf/in2)
= fRG1 + fRG2 + fRL1 for longitudinal deck girder, as specified in
5C-5-A1/9.5.2, in N/cm2 (kgf/cm2, lbf/in2)
Kt = 0.25(1 + 3ti/ta) ≤ 1.25
ti = net plate thickness of inserted plate, in mm (in.)
ta = net plate thickness of plate adjacent to the inserted plate, in mm (in.)
cf is as defined in 5C-5-A1/7.5.1.

818 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 1 Guide for Fatigue Strength Assessment of Container Carriers 5C-5-A1

FIGURE 6
Side Hatch Corners (1998)
li

ts
li

bd
Insert Plate ts
Insert Plate
ti ti

bi

bi
tc tc

longitudinal direction
(Strength Deck & Lower (Hatch Coaming Top)
Deck)

li1

bd ts

Insert Plate

ti
bi

li2

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 819
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 1 Guide for Fatigue Strength Assessment of Container Carriers 5C-5-A1

FIGURE 7
Circular Shape

φ
φ R
R
C

longitudinal direction

without cutout with cutout

FIGURE 8
Double Curvature Shape

φ R φ
2

R
2
R1
C
R1

θ longitudinal θ
direction

without cutout with cutout

FIGURE 9
Elliptical Shape

φ φ
R2
R1 R2
R1
C

longitudinal direction

without cutout with cutout

820 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 1 Guide for Fatigue Strength Assessment of Container Carriers 5C-5-A1

FIGURE 10
Hatch Corner for Longitudinal Deck Girder (1998)

ti bi

td td
Insert Plate

bi
li li

longitudinal
direction

11 Stress Concentration Factors Determined from Finite Element

Analysis

11.1 General (1998)

S-N data and stress concentration factors (SCFs) are related to each other and therefore should be
considered together so that there is a consistent basis for the fatigue assessment.
The following guidance is intended to help make correct decisions.

11.3 S-N Data (1998)

S-N data are presented as a series of straight-lines plotted on log-log scale. The data reflect the results of
numerous tests which often display considerable scatter. The recommended design curves for different
types of structural details and welded connections recognize the scatter in test results in that the design
curves have been based on the selection of the lower bound, 95% confidence limit. In other words, about
2.5% of the test failure results fall below this curve. Treating the design curve in this manner introduces a
high, yet reasonable degree of conservatism in the design and fatigue evaluation processes.
Individual S-N curves are presented to reflect certain generic structural geometries or arrangements.
5C-5-A1/Table 1 and 5C-5-A1/9.3 contain sketches of typical weld connections and other details in ship
structure, giving a list of the S-N classification. This information is needed to assess the fatigue strength of
a detail. Also needed is a consistent way to establish the demands or load effects placed on the detail so
that a compatible assessment can be made of the available strength versus the demand. Here is where
interpretation and judgment enter the fatigue assessment.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 821
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 1 Guide for Fatigue Strength Assessment of Container Carriers 5C-5-A1

S-N curves are obtained from laboratory sample testing. The applied reference stress on the sample which
is used to establish the S-N data is referred to as the nominal stress. The nominal stress is established in a
simple manner, such as force divided by area and bending moment divided by section modulus (P/A &
M/SM). The structural properties used to establish the nominal stress are taken from locations away from
any discontinuities to exclude local stress concentration effects arising from the presence of a weld or other
local discontinuity. In an actual structure, it is rare that a match will be found between the tested sample
geometry and loadings. One is then faced with the problem of making the appropriate interpretation.

11.5 S-N Data and SCFs (2003)

Selection of appropriate S-N data is straight-forward with respect to “standard details” offered in
5C-5-A1/Table 1 or other similar reference. However, in the case of welded connections in complex
structures, it is required that SCFs be used to modify the nominal stress range. An example of the need to
modify the nominal stress for fatigue assessment purposes is shown in 5C-5-A1/Figure 11 below, relating
to a hole drilled in the middle of a flat plate traversed by a butt weld.
In this example, the nominal stress SN is P/Area, but the stress to be used to assess the fatigue strength at
point A is SA or SN·SCF. This example is deceptively simple because it does not tell the entire story. The
prerequisite of the example is that one needs to have a definitive and consistent basis to obtain the SCF.
There are reference books which indicate that based on the theory of elasticity, the SCF to be applied in
this case is 3.0. However, when the SCF is computed using the finite element analysis techniques, the SCF
obtained can be quite variable depending on the mesh size. The example does not indicate which S-N
curve should be applied, nor does the example show how the selection of the design S-N data could be
affected by the mentioned finite element analysis issues. Therefore, if such interpretation questions exist
for a simple example, the higher difficulty of appropriately treating more complex structures should be evident.
Referring to the S-N curves to be applied to welded connections (for example, S-N curves, D-W in
5C-5-A1/Figure 1) the SCFs resulting from the presence of the weld itself are already accounted for in
these curves. If one were to have the correct stress distribution in the region – from the weld to a location
sufficiently away from the weld toe (where the stress is suitably established by the nominal stress obtained
from P/A and M/SM) – the stress distribution may be generically separated into three distinct segments, as
shown in the 5C-5-A1/Figure 12, below.
• Region III is a segment where the stress gradient is controlled by the nominal stress gradient.
• Region II is a segment where the nominal stress gradient is being modified due to the presence of other
structure such as the bracket end shown in the figure. This must be accounted for to obtain an
appropriate stress at the weld toe to be used in the fatigue analysis.
• Region I is a segment where the stress gradient is being modified due to the presence of the weld metal
itself. The stress concentration due to the weld is already accounted for in the S-N design curve and
need not be discussed further. Since the typical way to determine the stress distribution is via
planar/linear elements which ignore the weld, this is consistent with the method of analysis.
This general description of the stress distribution is again inconclusive because one does not know in
advance and with certainty the distances from the weld toe where the indicated changes of slope for the stress
gradient occur. For this reason, definite rules need to be established to determine the slopes, then criteria
can be established and used to find the stress at the weld toe which is to be used in the fatigue assessment.
In this regard, two approaches can be used to find the stress at the weld toe, which reflect two methods of
structural idealization. One of these arises from the use of a conventional beam element idealization of the
structure including the end bracket connection, and the other arises from the use of a fine mesh finite
element idealization. Using a beam element idealization, the nominal stress at any location (i.e., P/A and
M/SM) can be obtained (see 5C-5-4/Figure 7 for a sample beam element model). In the beam element
idealization there will be difficulty in accounting for the geometric stress concentration due to the presence
of other structure; this is the “Segment II” stress gradient previously described. In the beam modeling
approach shown in the figure, the influence on stresses arising from the “carry over” of forces and bending
moments from adjacent structural elements has been approximately accounted for. At the same time, the
strengthening effect of the brackets has been ignored. Hence for engineering purposes, this approach is
considered to be sufficient in conjunction with the nominal stress obtained at the location of interest and
the nominal S-N curve, i.e., the F or F2 Class S-N data, as appropriate.

822 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 1 Guide for Fatigue Strength Assessment of Container Carriers 5C-5-A1

In the fine mesh finite element analysis approach, one needs to define the element size to be used. This is
an area of uncertainty because the calculated stress distribution can be unduly affected by both the
employed mesh size and the uniformity of the mesh adjacent to the weld toe. Therefore, it is necessary to
establish “rules”, as given below, to be followed in producing the fine mesh model adjacent to the weld
toe. Further, since the area adjacent to the weld toe (or other discontinuity of interest) may be experiencing
a large and rapid change of stress (i.e., a high stress gradient) it is also necessary to provide a rule which
can be used to establish the stress at the location where the fatigue assessment is to be made.
5C-5-A1/Figure 13 shows an acceptable method which can be used to extract and interpret the “near weld
toe” element stresses and to obtain a (linearly) extrapolated stress at the weld toe. When plate or shell elements
are used in the modeling, it is recommended that each element size is to be equal to the plate thickness.
When stresses are obtained in this manner, the use of the E Class S-N data is considered acceptable.
Weld hot spot stress can be determined from linear extrapolation of surface component stresses at t/2 and
3t/2 from weld toe. The principal stresses at hot spot are then calculated based on the extrapolated stresses
and used for fatigue evaluation. Description of the numerical procedure is given in 5C-5-A1/13.7, below.

FIGURE 11
(1998)
S N = P/Area

A
P
SA

SCF = SA / SN

FIGURE 12
(1998)
Calculated Stress

Physical Stress

I Bracket
II
III

Weld

Stiffener

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 823
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 1 Guide for Fatigue Strength Assessment of Container Carriers 5C-5-A1

FIGURE 13
(2003)
Peak Stress

Weld Toe "Hot Spot" Stress

t Weld Toe

~
~ t Weld Toe Location

t/2

3t/2

11.7 Calculation of Hot Spot Stress for Fatigue Analysis of Ship Structures (2003)
The algorithm described in the following is applicable to obtain the hot spot stress for the point at the toe
of a weld. The weld typically connects either a flat bar member or a bracket to the flange of a longitudinal
stiffener, as shown below in 5C-5-A1/Figure 14.
Consider the four points, P1 to P4, measured by the distances X1 to X4 from the weld toe, designated as the
origin of the coordinate system. These points are the centroids of four neighboring finite elements, the first
of which is adjacent to the weld toe. Assuming that the applicable surface component stresses, Si, at Pi
have been determined from FEM analysis, the corresponding stresses at “hot spot”, i.e., the stress at the
weld toe can be determined by the following procedure:
11.7.1
Select two points, L and R, such that points L and R are situated at distances t/2 and 3t/2 from the
weld toe; i.e.,
XL = t/2, XR = 3t/2
where t denotes the thickness of the member to which elements 1 to 4 belong (e.g., the flange of a
longitudinal stiffener).
11.7.2
Let X = XL and compute the values of four coefficients as follows:
C1 = [(X − X2)(X − X3)(X − X4)] / [(X1 − X2)(X1 − X3)(X1 − X4)]

C2 = [(X − X1)(X − X3)(X − X4)] / [(X2 − X1)(X2 − X3)(X2 − X4)]

C3 = [(X − X1)(X − X2)(X − X4)] / [(X3 − X1)(X3 − X2)(X3 − X4)]

C4 = [(X − X1)(X − X2)(X − X3)] / [(X4 − X1)(X4 − X2)(X4 − X3)]

The corresponding stress at Point L can be obtained as:
SL = C1S1 + C2 S2 + C3 S3 + C4 S4

824 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 1 Guide for Fatigue Strength Assessment of Container Carriers 5C-5-A1

11.7.3
Let X = XR and repeat Step in 5C-5-A1/11.7.2 to determine four new coefficients, the stress at
Point R can be obtained likewise, i.e.,
SR = C1S1 + C2 S2 + C3 S3 + C4 S4

11.7.4 (2003)
The corresponding stress at hot spot, S0, is given by:

S0 = (3SL − SR)/2

FIGURE 14
(1998)
X
3t/2

t/2

(L) (R)

P1 P2 P3 P4
t

X1
X2
X3
X4

Footnotes:
The algorithm presented in the foregoing involves two types of operations. The first is to utilize the stress values at the centroid
of the four elements considered to obtain the estimates of the stress at Points L and R by way of an interpolation algorithm
known as Lagrange interpolation. The second operation is to make use of the stress estimates SL and SR to obtain the hot spot
stress via linear extrapolation.
While the Lagrange interpolation is applicable to any order of polynomial, it is not advisable to go beyond the 3rd order
(cubic). Also, the even order polynomials are biased; so that leaves the choice between a linear scheme and a cubic scheme.
Therefore, the cubic interpolation as described in 5C-5-A1/11.7.2 should be used. It can be observed that the coefficients, C1
to C4 are all cubic polynomials. It is also evident that, when X = Xj which is not equal to Xi all of the C’s vanish, except Ci;
and if X = Xi, Ci = 1.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 825
PART Appendix 2: Calculation of Critical Buckling Stresses

5C
CHAPTER 5 Vessels Intended to Carry Containers (130 meters
(427 feet) to 450 meters (1476 feet) in Length)

APPENDIX 2 Calculation of Critical Buckling Stresses

1 General
The critical buckling stresses for various structural elements and members may be determined in accordance
with this Appendix or other recognized design practices. Critical buckling stresses derived from experimental
data or analytical studies may be considered, provided well documented supporting data are submitted for
review.

3 Rectangular Plates (1998)

The critical buckling stresses for rectangular plate elements, such as plate panels between stiffeners; web
plates of longitudinals, girders, floors and transverses; flanges and face plates, may be obtained from the
following equations with respect to uniaxial compression, bending and edge shear, respectively.
fci = fEi, for fEi ≤ Pr fyi
fci = fyi[1 − Pr(1 − Pr) fyi /fEi], for fEi > Pr fyi
where
fci = critical buckling stress with respect to uniaxial compression, bending or edge shear,
separately, in N/cm2 (kgf/cm2, lbf/in2)
fEi = Ki[π2E/12(1 − v2)](tn /s)2, N/cm2 (kgf/cm2, lbf/in2)
Ki = buckling coefficient, as given in 5C-5-A2/Table 1
E = modulus of elasticity of the material, may be taken as 2.06 × 107 N/cm2
(2.1 × 106 kgf/cm2, 30 × 106 lbf/in2) for steel
v = Poisson’s ratio, may be taken as 0.3 for steel
tn = net thickness of the plate, in cm (in.)
s = spacing of longitudinals/stiffeners, in cm (in.)
Pr = proportional linear elastic limit of the structure, may be taken as 0.6 for steel
fyi = fy , for uniaxial compression and bending

= fy / 3 for edge shear

fy = specified minimum yield point of the material, in N/cm2 (kgf/cm2, lbf/in2)

826 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 2 Calculation of Critical Buckling Stresses 5C-5-A2

TABLE 1
Buckling Coefficient, Ki (1995)
For Critical Buckling Stress Corresponding to fL, fT, fb or fLT
I. Plate panel between stiffeners Ki
A Uniaxial compression l a. For f‘L, = f L: 4C1,
fL fL
1. Long plate b. For f‘L, = f L /3: 5.8C1,
l≥s S (see note)

f 'L f 'L

2. Wide plate fT a. For f‘T, = f T: [1 + (s/l)2]2C2

f 'T
l≥s b. For f‘T, = f T /3: 1.45[1 + (s/l)2]2C2
(see note)
S l

f 'T
fT

B Ideal Bending fb l fb
1. Long plate 24C1
s
l≥s
-fb -fb

2. Wide plate a. For 1.0 ≤ l/s ≤ 2.0: 24(s/l)2C2

fb
l≥s b. For 2.0 < l/s: 12(s/l)C2
-fb

s l

-fb

fb

C Edge Shear fLT Ki

[5.34 + 4 (s/l)2]C1
s fLT

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 827
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 2 Calculation of Critical Buckling Stresses 5C-5-A2

TABLE 1 (continued)
Buckling Coefficient, Ki (1995)
D Values of C1 and C2
1. For plate panels between angles or tee stiffeners
C1 = 1.1
C2 = 1.3 within the double bottom or double side*
C2 = 1.2 elsewhere
2. For plate panels between flat bars or bulb plates
C1 = 1.0
C2 = 1.2 within the double bottom or double side*
C2 = 1.1 elsewhere
* applicable where shorter edges of a panel are supported by rigid structural members, such as bottom, inner
bottom, side shell, inner skin bulkhead, double bottom floor/girder and double side web stringer.

II. Web of Longitudinal or Stiffener Ki

A Axial compression
Same as I.A.1 by replacing s with depth of the web and l with unsupported span
a. For f‘L = fL : 4C
b. For f‘L = fL/2:
5.2C
(see note)
where
C = 1.0 for angle or tee stiffeners
C = 0.33 for bulb plates
C = 0.11 for flat bars
B Ideal Bending
Same as I.B.1 by replacing s with depth of the web and l with unsupported span 24C

III. Flange and Face Plate Ki

Axial Compression 0.44

b2 b2

s = b2
l = unsupported span
Note:
In I.A. (II.A), Ki for intermediate values of f‘L / fl (f‘T / fT) may be obtained by interpolation between a and b.

828 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 2 Calculation of Critical Buckling Stresses 5C-5-A2

5 Longitudinal Deck Girders, Cross Deck Box Beams, Vertical Webs,

Longitudinals and Stiffeners

5.1 Axial Compression (2002)

The critical buckling stress fca, of a beam-column, i.e., the longitudinal and the associated effective plating,
with respect to axial compression, may be obtained from the following equations:
fca = fE, for fE ≤ Pr fy
fca = fy[1 − Pr(1 − Pr)fy /fE], for fE > Pr fy
where
fE = π2E/(l/r)2, in N/cm2 (kgf/cm2, lbf/in2)
l = unsupported span of the longitudinal or stiffener, in cm (in.), as defined in
5C-5-4/Figure 6.
r = radius of gyration of area, Ae, in cm (in.)
Ae = As + bwLtn
As = net sectional area of the longitudinals or stiffeners, excluding the associated plating,
in cm2 (in2)
bwL = effective width of the plating, as given in 5C-5-5/5.3.2, in cm (in.)
tn = net thickness of the plating, in cm (in.)
fy = minimum specified yield point of the longitudinal or stiffener under consideration,
N/cm2 (kgf/cm2, lbf/in2)
Pr and E are as defined in 5C-5-A2/3.

5.3 Bending
5.3.1 Longitudinals, Stiffeners and Frames (1998)
The allowable ultimate stress with respect to bending moment induced by lateral loads, fub, for a
longitudinal may be taken as fy. In this regard, the corresponding bending stress, fb, specified in
5C-5-5/5.5, is to be determined from the following equation:
fb = M/SMe N/cm2 (kgf/cm2, lbf/in2)
where
M = maximum total bending moment induced by lateral loads and the end
structures connected
= cm psl2/12 N-cm (kgf-cm, lbf-in)
cm = moment adjustment coefficient, and may be taken as 0.75

p = lateral pressure for the region considered, in N/cm2 (kgf/cm2, lbf/in2)

SMe = net section modulus of the longitudinals, in cm3 (in3), including the effective
breadth of the plating, be , at midspan. be may be taken as that given in
5C-5-4/Figure 7.
s is as defined in 5C-5-A2/3.
l is as defined in 5C-5-A2/5.1.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 829
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 2 Calculation of Critical Buckling Stresses 5C-5-A2

5.3.2 Longitudinal Deck Girders, Cross Deck Box Beams and Vertical Webs (1998)
The allowable ultimate stress with respect to bending moment, fub, for these structural members
may be taken as fy. In this regard, the corresponding bending stress, fb, specified in 5C-5-5/5.11, is
to be determined from the following equations:
5.3.2(a) Longitudinal Deck Girders inboard of Lines of Hatch Openings
fb = M/SM N/cm2 (kgf/cm2, lbf/in2)
where

M = kc1KC C1TM L2o ωM 105/(c2boαM ΓM) N-cm (kgf-cm, lbf-in)

k = 1.0 (1.0, 0.269)
SM = net section modulus of the longitudinal deck girder about its vertical neutral
axis (z axis of section C-C in 5C-5-4/Figure 4), in cm3 (in3)
c1 = 0.53 for centerline deck girders
= 0.42 for two side deck girders
Kc = 0.9kc
kc is specified in 5C-5-3/Table 1 for torsional moment.
∗
c2 = c3bo/ I CB + lo /Ig
c3 = 0.75 for centerline deck girder
= 0.425 for two side deck girders
∗
TM, Lo, ωM, lM, bo, lo, αM and ΓM are as defined in 5C-5-4/9.3 and C1 and I CB are as defined in
5C-5-4/17.7.2.
5.3.2(b) Cross Deck Box Beams where no Longitudinal Deck Girders are installed
fb = (Kc M1 + M2)/SM N/cm2 (kgf/cm2, lbf/in2)
where
M1 is defined in 5C-5-4/17.7.4. In calculation of M1, z is to be taken as 0.5 b1 where b1 is as defined
in 5C-5-4/17.7.4.
Kc = 0.9 kc
kc is specified in 5C-5-3/Table 1 for torsional moment.

M2 = kC2[0.5Qd1 + 0.25Qd2 n/(n + 1)]b1105

k = 0.17 (0.17, 0.046)
Qd1 = total dynamic container load in longitudinal direction on cross deck box
beam (above the bottom of the cross deck box beam), in kN (tf, Ltf)
= m1m2(1 − h5/h4) Fdl1
Qd2 = total dynamic container load in longitudinal direction on transverse
bulkhead, (below the bottom of cross deck box beam), in kN (tf, Ltf)
= m1m2(h5/h4) Fdl2
m1 = tier number of container stacks in the cargo hold under consideration
m2 = row number of container stacks in the cargo hold under consideration
h4 = m1hC

830 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 2 Calculation of Critical Buckling Stresses 5C-5-A2

h5 = vertical distance between inner bottom and the bottom of cross deck box
beam at center line, in m (ft)
Fdl1 = longitudinal dynamic container load Fdl,as specified in 5C-5-3/5.5.2(b), with
W of the maximum design container weight at a vertical height 0.5(h4 + h5),
measured from inner bottom
Fdl2 = longitudinal dynamic container load Fdl, as specified in 5C-5-3/5.5.2(b), with
W of the maximum design container weight at a vertical height 0.5h5,
measured from inner bottom
SM = net section modulus of the cross deck box beam clear of the hatch corner
under consideration about vertical axis (z axis of section A-A in
5C-5-4/Figure 4), in cm3 (in3)
W, C2, n and hC are as defined in 5C-5-4/17.5.3 and b1 is as defined in 5C-5-4/17.7.4.
5.3.2(c) Vertical Webs of Mid-hold Strength Bulkhead where no Horizontal Girder is Installed
fb = M/SM N/cm2 (kgf/cm2, lbf/in2)
where
M = kcFdtlv
k = 1.0 (1.0, 0.269)
c = 8330(m1 − 1)
m1 is as defined in 5C-5-A2/5.3.2(b)
Fdt = transverse dynamic container load, as specified in 5C-5-3/5.5.2(b), with W of
the maximum design container weight at the mid-span of vertical web of
span lv, in kN (tf, Ltf)
SM = net section modulus of the vertical web under consideration about the neutral
axis parallel to the longitudinal centerline plane of vessel, in cm3 (in3)
W and lv are as defined in 5C-5-4/17.5.3 and 5C-5-4/25.1, respectively.

5.5 Torsional/Flexural Buckling (1998)

The critical torsional/flexural buckling (ultimate) stress with respect to axial compression, e.g., of a
longitudinal or stiffener including its associated plating (effective width, bwL) may be obtained from the
following equations:
fct = fET , for fET ≤ Pr fy
fct = fy[1 − Pr(1 − Pr)fy /fET], for fET > Pr fy
where fET may be determined as follows.

5.5.1 Longitudinals, Stiffeners and Frames (2002)

fET = E[K/2.6 + (nπ/l)2Γ + Co(l/nπ)2/E]/Io[1 + Co(l/nπ)2/Io fcL], in N/cm2 (kgf/cm2, lbf/in2)
where
fct = critical torsional/flexural buckling (ultimate) stress with respect to axial
compression, N/cm2 (kgf/cm2, lbf/in2).
K = St. Venant torsion constant for the stiffener’s cross section, excluding the
associated plating, in cm4 (in4)

= 1/3[bf t 3f + dw t w3 ]

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 831
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 2 Calculation of Critical Buckling Stresses 5C-5-A2

Io = polar moment of inertia of the stiffener’s cross section, excluding the associated
plating, about the toe (intersection of web and plating), in cm4 (in4)

= Ix + mIy + As( xo2 + y o2 )

Ix, Iy = moment of inertia of the longitudinal about the x- and y-axis, respectively,
through the centroid of the longitudinal, excluding the plating (x-axis
perpendicular to the web), in cm4 (in4)
m = 1.0 − u(0.7 − 0.1dw /bf)
u = unsymmetry factor
= 1 − 2b1/bf
xo = horizontal distance between centroid of stiffiner As and centerline of the web
plate, in cm (in.)
yo = vertical distance between the centroid of the longitudinal’s cross section As
and its toe, in cm (in.)
dw = depth of the web, in cm (in.)
tw = net thickness of the web, in cm (in.)
bf = total width of the flange/face plate, in cm (in.)
b1 = smaller outstanding dimension of flange with respect to web’s centerline (see
5C-5-A2/Figure 1), in cm (in.)
tf = net thickness of the flange/face plate, in cm (in.)

Co = E t n3 /3s

Γ = warping constant, in cm6 (in6)

≅ mIyf d w2 + d w3 t w3 /36

Iy f = tf b 3f (1.0 + 3.0u2dwtw/As)/12, cm4 (in4)

fcL = critical buckling stress for the associated plating corresponding to n-half
waves, in N/cm2 (kgf/cm2, lbf/in2)
= π2E(n/α + α/n)2(tn/s)2/12(1 − v2)
α = l/s
n = number of half-waves which yield smallest fET
fy = minimum specified yield point of the longitudinal or stiffener under
consideration, N/cm2 (kgf/cm2, lbf/in2)
Pr, E, s and v are as defined in 5C-5-A2/3.

As, tn and l are as defined in 5C-5-A2/5.1.

832 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 2 Calculation of Critical Buckling Stresses 5C-5-A2

FIGURE 1
Net Dimensions and Properties of Stiffeners (1998)
bf

b2 b1
1

tf

xo
CENTROID OF WEB
AND FACE PLATE
(NET SECTION)

tw

yo
dw

tp

be

1 = point considered for

coefficient, Cn given
in 5C-5-A1/Figure 3

5.5.2 Longitudinal Deck Girders, Cross Deck Box Beams, and Vertical Webs
fET = E[K/2.6 + (π/l)2Γ]/Io
fct = critical torsional/flexural buckling (ultimate) stress with respect to axial
compression, in N/cm2 (kgf/cm2, lbf/in2).
K = St. Venant torsion constant for the member’s cross section, in cm4 (in4)
Γ = warping constant, in cm6 (in6)
Io = polar moment of inertia of the member’s cross section with respect to shear
center, in cm4 (in4)

= Ix + Iy + A( y o2 + xo2 )

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 833
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 2 Calculation of Critical Buckling Stresses 5C-5-A2

Ix, Iy = moment of inertia of the member’s cross section about the x- and y-plane,
through its neutral axis (x-plane perpendicular to the web), in cm4 (in4)
yo = vertical distance between the centroid of the member’s cross section A and
its shear center, in cm (in.)
xo = horizontal distance between the centroid of member’s cross section A and its
shear center, in cm (in.)
A = total net sectional area of the structural members, in cm2 (in2)
l is as defined in 5C-5-A2/5.1
For illustration purposes, the torsional properties are shown in 5C-5-A2/Figure 2 for I section with
two planes of symmetry and channel section with one plane of symmetry.

FIGURE 2
Torsional Properties
bf bf

y y

tf tf
tw

x h x
h
tw

tf tf e

bf bf

For I section with two axes of symmetry:

e = 0
3 3
2 b f t f + h tw
K =
3
3
t f h 2b f
Γ =
24
For channel section with one axis of symmetry:

3 bf 2 t f
e =
6 b f t f + h tw

3 3
2 b f t f + h tw
K =
3
3
t f h 2 b f (3 b f t f + 2 h t w )
Γ =
12 (6 b f t f + h t w )

834 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 2 Calculation of Critical Buckling Stresses 5C-5-A2

7 Stiffened Panels (1998)

For large stiffened panels between bulkheads or panels stiffened in one direction between transverses and
girders, the critical buckling stresses with respect to uniaxial compression may be determined from the
following equations:
fci = fEi for fEi ≤ Pr fy

fci = fy[1 − Pr(1 − Pr) fy /fEi], for fEi > Pr fy

where
fEi = kL π2(DLDT)1/2/tL b2 in the longitudinal direction, N/cm2 (kgf/cm2, lbf/in2)

fEi = kT π2(DLDT)1/2/tT l2 in the transverse direction, N/cm2 (kgf/cm2, lbf/in2)

kL = 4 for l/b ≥ 1

= [1/φ 2L + 2η + φ 2L ] for l/b < 1

kT = 4 for b/l ≥ 1

= [1/φ T2 + 2η + φ T2 ] for b/l < 1

DL = EIL/sL(1 − v2)
DL = Etn3/12(1 − v2) if no stiffener in the longitudinal direction
DT = EIT/sT(1 − v2)
DT = Etn3/12(1 − v2) if no stiffener in the transverse direction
l, b = length and width between transverse bulkheads and side shell/longitudinal bulkheads,
respectively, cm (in.) (See 5C-5-A2/Figure 2.)
tL, tT = equivalent net thickness of the plating and smeared stiffener in the longitudinal and
transverse direction, respectively, cm (in.)
= (sLtn + AsL)/sL or (sTtn + AsT)/sT
sL, sT = spacing of longitudinals and transverses, respectively, cm (in.) (See 5C-5-A2/Figure 2.)
φL = (l/b)(DT/DL)1/4
φT = (b/l)(DL/DT)1/4
η = [(IpLIpT)/(ILIT)]1/2
AsL, AsT = net sectional area of the longitudinal and transverse, excluding the associated plating,
respectively, cm2 (in2)
IpL, IpT = moment of inertia of the effective plating (effective breadth due to shear lag) alone
about the neutral axis of the combined cross section, including stiffener and plating,
in the longitudinal and transverse direction, respectively, cm4 (in4)
IL, IT = moment of inertia of the stiffener (one) with effective plating in the longitudinal and
transverse direction, respectively, cm4 (in4)
If no stiffener, the moment of inertia is calculated for the plating only.
Pr, fy, E and v are as defined in 5C-5-A2/3. tn is as defined in 5C-5-A2/5.1.
Except for deck panels, when the lateral load parameter, qo, defined below is greater than 5, reduction of
the critical buckling stresses given above is to be considered.
qo = pnl4/(π4tLDL) if no stiffener in the transverse direction
qo = pnb4/(π4tT DT) for all other cases

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 835
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 2 Calculation of Critical Buckling Stresses 5C-5-A2

where
pn = average net lateral pressure, N/cm2 (kgf/cm2, lbf/in2)

DL, DT, b, l, tT, and tL are as defined above.

In this regard, the critical buckling stress may be approximated by:
f ci′ = Ro fci N/cm2 (kgf/cm2, lbf/in2)
where
Ro = 1 − 0.045(qo − 5) for qo ≥ 5

For deck panels, Ro = 1.0 and f ci′ = fci

FIGURE 3
l
T.B./S.S

sT

pn
longitudinal
b sL

L.B.

transverse plating, tn T.B.

T.B.

9 Deep Girders, Webs and Stiffened Brackets

9.1 Critical Buckling Stresses of Web Plates and Large Brackets (1998)
The critical buckling stresses of web plates and large brackets between stiffeners may be obtained from the
equations given in 5C-5-A2/3 for uniaxial compression, bending and edge shear.

9.3 Effects of Cut-outs (1998)

The depth of cut-outs, in general, is to be not greater than dw/3, where dw is the depth of the web, and the
stresses in the area calculated are to account for the local increase due to the cut-out.
When cut-outs are present in the web plate, the effects of the cut-outs on reduction of the critical buckling
stresses are to be considered as outlined below:
9.3.1 Reinforced by Stiffeners Around Boundaries of Cut-outs
When reinforcement is made by installing straight stiffeners along the boundaries of the cut-outs,
the critical buckling stresses of web plate between stiffeners with respect to compression and shear
may be obtained from equations given in 5C-5-A2/3

836 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 2 Calculation of Critical Buckling Stresses 5C-5-A2

9.3.2 Reinforced by Face Plates Around Contour of Cut-outs

When reinforcement is made by adding face plates around the contours of the cut-outs, the critical
buckling stresses with respect to compression, bending and shear may be obtained from equations
given in 5C-5-A2/3, without reduction, provided the net sectional area of the face plate is not less
than 8 t w2 , where tw is the net thickness of the web plate and the depth of the cut-outs is not greater
than dw/3, where dw is the depth of the web.
9.3.3 No Reinforcement Provided
When reinforcement is not provided, the buckling strength of web plate surrounding the cut-out
may be treated as a strip of plate with one edge free and the other edge simply supported.

9.5 Tripping (1998)

To prevent tripping of deep girders and webs with wide flanges, tripping brackets are to be installed with a
spacing generally not greater than 3 meters (9.84 feet).
Design of tripping brackets may be based on the force, P, acting on the flange, as given by the following
equation:
P = 0.02fcl (Af + Aw /3)

Af
P

1/3 Aw TRIPPING BRACKET

where
fcl = critical lateral buckling stress with respect to axial compression between tripping
brackets, N/cm2 (kgf/ cm2, lbf/in2)
fcl = fce for fce ≤ Pr fy

= fy[1 − Pr(1 − Pr) fy /fce] for fce > Pr fy

fce = 0.6E[(bf /tf) (tw /dw)3] N/cm2 (kgf/cm2, lbf/in2)
Af = net cross sectional area of the flange/face plate, in cm2 (in2)

Aw = net cross sectional area of the web, in cm2 (in2)

bf , tf , dw , tw are as defined in 5C-5-A2/5.5.1.
E, Pr and fy are as defined in 5C-5-A2/3.

11 Stiffness and Proportions

To fully develop the intended buckling strength of the assemblies of structural members and panels, supporting
elements of plate panels and longitudinals are to satisfy the following requirements for stiffness and proportion
in highly stressed regions.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 837
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 2 Calculation of Critical Buckling Stresses 5C-5-A2

11.1 Stiffness of Longitudinals (1998)

The net moment of inertia of the longitudinals, io, with effective plating is to be not less than that given by
the following equation:
3
s tn
io = γo cm4 (in4)
12(1 − v 2 )
where
γo = (2.6 + 4.0δ)α2 + 12.4α − 13.2α1/2

δ = A/(stn)

α = l/s
s = spacing of longitudinals/stiffeners, in cm (in.)
tn = net thickness of plating supported by the longitudinal, in cm (in.)
v = Poisson’s ratio
= 0.3 for steel
A = net sectional area of the longitudinal section (excluding effective plating), in cm2 (in2)
l = unsupported span of the longitudinal, in cm (in.)

11.3 Stiffness of Web Stiffeners (1998)

The net moment of inertia, i, of the web stiffener with the effective breadth of net plating not exceeding s
or be, as specified in 5C-5-4/11.5, whichever is less, is not to be less than that obtained from the following
equations:
i = 0.17lt3(l/s)3 cm4 (in4) for l/s ≤ 2.0
i = 0.34lt3(l/s)2 cm4 (in4) for l/s > 2.0
where
l = length of stiffener between effective supports, in cm (in.)
t = required net thickness of web plating, in cm (in.)
s = spacing of stiffeners, in cm (in.)

11.5 Stiffness of Supporting Members (1998)

The net moment of inertia of the supporting members such as transverses, girders and webs is to be not less
than that obtained from the following equation:
Is/io ≥ 0.2(Bs /l)3(Bs /s)
where
Is = moment of inertia of the supporting member, including the effective plating, in cm4 (in4)
io = moment of inertia of the longitudinals/stiffeners, including the effective plating, in
cm4 (in4)
Bs = unsupported span of the supporting member, in cm (in.)

l and s are as defined in 5C-5-A2/11.1.

838 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 2 Calculation of Critical Buckling Stresses 5C-5-A2

11.7 Proportions of Flanges and Face Plates (1998)

The breadth-thickness ratio of flanges and face plates of longitudinals and girders is to satisfy the limits
given below:
b2/tf ≤ 0.4(E/fy)1/2
where
b2 = breadth of flange, as given in 5C-5-A2/Figure 1, in cm (in.)
tf = net thickness of flange/face plate, in cm (in.)
E and fy are as defined in 5C-5-A2/3.

11.9 Proportions of Webs of Longitudinals and Stiffeners (1998)

The depth-thickness ratio of webs of longitudinals and stiffeners is to satisfy the limits given below:
dw /tw ≤ 1.5(E/fy)1/2 for angles and tee-bars

dw /tw ≤ 0.85(E/fy)1/2 for bulb plates

dw /tw ≤ 0.5(E/fy)1/2 for flat bars

where
dw and tw are as defined in 5C-5-A2/5.5 and E and fy are as defined in 5C-5-A2/3.
When these limits are complied with, the assumption on buckling control stated in 5C-5-5/5.1.2(e) is
considered satisfied. If not, the buckling strength of the web is to be further investigated, as per 5C-5-A2/3.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 839
PART Appendix 3: Definitions of Hull Girder Torisional Properties

5C
CHAPTER 5 Vessels Intended to Carry Containers (130 meters
(427 feet) to 450 meters (1476 feet) in Length)

APPENDIX 3 Definition of Hull Girder Torsional Properties

1 General (1998)
The hull girder torsional properties may be calculated based on the thin walled beam theory. The hull
girder section of a typical container carrier is usually modeled as an assemblage of segments (plates) connected
to nodal points, consisting of open zones and closed cells. The following sections define the torsional
properties used in the Rules. The torsional properties for each design will be calculated with SafeHull software.

3 Warping Function, ω (1998)

The warping function for node “N”, ω(s)N, may be obtained from the following equation:
ω(s)N = ω(s) *N + e xN
"N "
⎛ qs ⎞
ω(s) *N = ∫ ⎜⎜⎝ r
o
s −
ts
⎟⎟ds
⎠
where
rs = distance from the origin to the axis of each segment
The origin is taken as the intersection of the centerline and baseline of the vessel.
qs = specific stress flow of cell to which each segment belongs
ts = plate thickness of each segment with the area of longitudinal stiffeners smeared
e = distance of shear center of the hull girder section, measured from the baseline,
positive upward
xN = horizontal distance from the centerline of the vessel to node “N”
s = length along girth
The specific stress flow, q, of each cell may be obtained from the following set of equations; the number of
the equations is equal to the number of cells in hull girder section.
ds ds ds
qi ∫ − q i −1 ∫ Div − q i +1 ∫ Div = 2 Ai , (i = 1, 2, − − − k )
i t t t
where
qi = specific flow for cell “i”
qi − 1 = specific flow for adjacent cell “i − 1”
qi + 1 = specific flow for adjacent cell “i + 1”
k = number of the cells in hull girder section
Ai = enclosed area of cell “i”
t = plate thickness of segment with the area of longitudinal stiffeners smeared

840 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 3 Definition of Hull Girder Torsional Properties 5C-5-A3

5 Location of Shear Center, e (1998)

The location of the shear center, e, of the hull girder, measured from the baseline may be obtained from the
following equation:
e = − (Iωy /Iy)
where
Iωy = sectorial moment

∫ ω (s)
*
= N x N t s ds
c

Iy = hull girder moment of inertia about the centerline of the vessel

C = total girth length

ω(s) *N , xN , ts are as defined in 5C-5-A3/3.

7 Warping Constant, Γ (1998)

The warping constant, Γ, for the hull girder section may be obtained from the following equation:
p ln

Γ = ∑t ∫ω
n −1
n
2
( s )ds
0

where
p = number of segments in hull girder section
ln = length of segment “n”
tn = plate thickness of segment “n” with the area of longitudinal stiffeners smeared

ω(s) = warping function

9 St. Venant Torsional Constant, J (1998)

The St. Venant torsional constant, J, may be obtained from the following equation:
k
Ai2
J =4 ∑
i =1
∫ ds / t
where
Ai = enclosed area of cell “i”
t = plate thickness of segment in cell “i” without smearing longitudinal stiffeners
k is as defined in 5C-5-A3/3.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 841
PART Appendix 4: Guide for Hull Girder Ultimate Strength Assessment of Container Carriers

5C
CHAPTER 5 Vessels Intended to Carry Containers (130 meters
(427 feet) to 450 meters (1476 feet) in Length)

APPENDIX 4 Guide for Hull Girder Ultimate Strength

Assessment of Container Carriers (2010)

1 General
The hull structure may be verified for compliance with the hull girder ultimate strength requirements using
this Appendix. For vessels that are to be designed for compliance with the Common Structural Rules
(CSR) for oil carriers and bulk carriers, the specific hull girder ultimate strength requirements in Part 5A
and 5B of the Steel Vessel Rules are to be applied.
In general, the requirements are applicable to the hull structure within 0.4L amidships in sea-going
conditions. For vessels that are subject to higher bending moment, the hull girder ultimate strength in the
forebody region is also to be verified.

3 Vertical Hull Girder Ultimate Limit State

The vertical hull girder ultimate bending capacity is to satisfy the following limit state equation:
MU
γSMsw + γWMw ≤
γR
where
Msw = still water bending moment, in kN-m (tf-m), in accordance with 3-2-1/3.3
Mw = maximum wave-induced bending moment, in kN-m (tf-m), in accordance with
5C-5-3/5.1.1, using kw = 1.0 for wave hogging bending moment and kw = 1.84 –
0.56Cb for wave sagging bending moment
MU = vertical hull girder ultimate bending capacity, in kN-m (tf-m), as defined in 5C-5-A4/5

γS = 1.0 partial safety factor for the still water bending moment
γw = 1.20 partial safety factor for the vertical wave bending moment covering
environmental and wave load prediction uncertainties
γR = 1.10 partial safety factor for the vertical hull girder bending capacity covering
material, geometric and strength prediction uncertainties
In general, for vessels where the hull girder ultimate strength is evaluated with gross scantlings, γR is to be
taken as 1.25.

842 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 4 Hull Girder Ultimate Strength Assessment of Container Carriers 5C-5-A4

5 Hull Girder Ultimate Bending Moment Capacity

5.1 General
The ultimate bending moment capacities of a hull girder section, in hogging and sagging conditions, are
defined as the maximum values (positive MUH, negative MUS) on the static nonlinear bending moment-
curvature relationship M-κ. See 5C-5-A4/Figure 1. The curve represents the progressive collapse behavior
of the hull girder under vertical bending. Hull girder failure is controlled by buckling, ultimate strength and
yielding of longitudinal structural elements.

FIGURE 1
Bending Moment – Curvature Curve M-κ (2010)
M
Hogging Condition
MUH

MUS
Sagging Condition

The curvature of the critical inter-frame section,κ, is defined as:

θ -1
κ= m
l
where:
θ = relative angle rotation of the two neighboring cross-sections at transverse frame
positions
l = transverse frame spacing in m, i.e., span of longitudinals
The method for calculating the ultimate hull girder capacity is to identify the critical failure modes of all
main longitudinal structural elements.
Longitudinal structural members compressed beyond their buckling limit have reduced load carrying
capacity. All relevant failure modes for individual structural elements, such as plate buckling, torsional
stiffener buckling, stiffener web buckling, lateral or global stiffener buckling and their interactions, are to
be considered in order to identify the weakest inter-frame failure mode.
The effects of shear force, torsional loading, horizontal bending moment and lateral pressure are neglected.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 843
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 4 Hull Girder Ultimate Strength Assessment of Container Carriers 5C-5-A4

5.3 Physical Parameters

For the purpose of describing the calculation procedure in a concise manner, the physical parameters and
units used in the calculation procedure are given below.
5.3.1 Hull Girder Load and Cross Section Properties
Mi = hull girder bending moment, in kN-m (tf-m)
Fi = hull girder longitudinal force, in kN (tf)
Iv = hull girder moment of inertia, in m4

SM = hull girder section modulus, in m3

SMdk = elastic hull girder section modulus at deck at side, in m3

SMkl = elastic hull girder section modulus at bottom, in m3

κ = curvature of the ship cross section, in m-1

zj = distance from baseline, in m

5.3.2 Material Properties

σyd = specified minimum yield stress of the material, in N/cm2 (kgf/cm2)

E = Young’s modulus for steel, 2.06 × 107 N/cm2 (2.1 × 106 kgf/cm2)
ν = Poisson’s ratio, may be taken as 0.3 for steel
Φ = edge function as defined in 5C-5-A4/5.9.2
ε = relative strain defined in 5C-5-A4/5.9.2
5.3.3 Stiffener Sectional Properties
The properties of a longitudinal’s cross section are shown in 5C-5-A4/Figure 2.
As = sectional area of the longitudinal or stiffener, excluding the associated plating, in cm2
b1 = smaller outstanding dimension of flange with respect to centerline of web, in cm
bf = total width of the flange/face plate, in cm
dw = depth of the web, in cm
tp = net thickness of the plating, in cm
tf = net thickness of the flange/face plate, in cm
tw = net thickness of the web, in cm
xo = distance between centroid of the stiffener and centerline of the web plate, in cm
yo = distance between the centroid of the stiffener and the attached plate, in cm

844 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 4 Hull Girder Ultimate Strength Assessment of Container Carriers 5C-5-A4

FIGURE 2
Dimensions and Properties of Stiffeners (2010)
bf

b2 b1

tf

xo
CENTROID OF WEB
AND FACE PLATE
(NET SECTION)

tw

yo
dw

tp

be

5.5 Calculation Procedure

The ultimate hull girder bending moment capacity MU is defined as the peak value of the curve with
vertical bending moment M versus the curvature κ of the ship cross section as shown in 5C-5-A4/Figure 1.
The curve M-κ is obtained by means of an incremental-iterative approach. The steps involved in the
procedure are given below.
The bending moment Mi which acts on the hull girder transverse section due to the imposed curvature κi is
calculated for each step of the incremental procedure. This imposed curvature corresponds to an angle of
rotation of the hull girder transverse section about its effective horizontal neutral axis, which induces an
axial strain ε in each hull structural element.
The stress σ induced in each structural element by the strain ε is obtained from the stress-strain curve σ-ε
of the element, which takes into account the behavior of the structural element in the nonlinear elasto-
plastic domain.
The force in each structural element is obtained from its area times the stress and these forces are summed
to derive the total axial force on the transverse section. Note the element area is taken as the total net area
of the structural element. This total force may not be zero as the effective neutral axis may have moved due
to the nonlinear response. Hence, it is necessary to adjust the neutral axis position, recalculate the element
strains, forces and total sectional force, and iterate until the total force is zero.
Once the position of the new neutral axis is known, then the correct stress distribution in the structural
elements is obtained. The bending moment Mi about the new neutral axis due to the imposed curvature κi is
then obtained by summing the moment contribution given by the force in each structural element.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 845
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 4 Hull Girder Ultimate Strength Assessment of Container Carriers 5C-5-A4

The main steps of the incremental-iterative approach are summarized as follows:

Step 1 Divide the hull girder transverse section into structural elements, (i.e., longitudinal stiffened panels
(one stiffener per element), hard corners and transversely stiffened panels), see 5C-5-A4/5.7.
Step 2 Derive the stress-strain curves (also known as the load-end shortening curves) for all structural
elements, see 5C-5-A4/5.9.
Step 3 Derive the expected maximum required curvature, κF. The curvature step size Δκ is to be taken as
κF/300. The curvature for the first step, κ1 is to be taken as Δκ.
Derive the neutral axis zNA-i for the first incremental step (i = 1) with the value of the elastic hull girder
section modulus, see 3-2-1/9.
Step 4 For each element (index j), calculate the strain εij = κi(zj – zNA-i) corresponding to κi, the corresponding
stress σj , and hence the force in the element σj Aj. The stress σj corresponding to the element strain εij is to
be taken as the minimum stress value from all applicable stress-strain curves σ-ε for that element.
Step 5 Determine the new neutral axis position zNA-i by checking the longitudinal force equilibrium over
the whole transverse section. Hence, adjust zNA-i until:
Fi = 10-3 ΔAjσj = 0
Note σj is positive for elements under compression and negative for elements under tension. Repeat from
Step 4 until equilibrium is satisfied. Equilibrium is satisfied when the change in neutral axis position is less
than 0.0001 m.
Step 6 Calculate the corresponding moment by summing the force contributions of all elements as follows:

Mi = 10-3 ∑σ j Aj (z j − z NA−i )
Step 7 Increase the curvature by Δκ, use the current neutral axis position as the initial value for the next
curvature increment and repeat from Step 4 until the maximum required curvature is reached. The ultimate
capacity is the peak value Mu from the M-κ curve. If the peak does not occur in the curve, then κF is to be
increased until the peak is reached.
The expected maximum required curvature κF is to be taken as:
(
max SM dk σ yd , SM kl σ yd )
κF = 3
EI v

5.7 Assumptions and Modeling of the Hull Girder Cross-section

In applying the procedure described in this Appendix, the following assumptions are to be made:
i) The ultimate strength is calculated at a hull girder transverse section between two adjacent transverse
webs.
ii) The hull girder transverse section remains plane during each curvature increment.
iii) The material properties of steel are assumed to be elastic, perfectly plastic.
iv) The hull girder transverse section can be divided into a set of elements which act independently of
each other.
v) The elements making up the hull girder transverse section are:
• Longitudinal stiffeners with attached plating, with structural behavior given in 5C-5-A4/5.9.2,
5C-5-A4/5.9.3, 5C-5-A4/5.9.4, 5C-5-A4/5.9.5 and 5C-5-A4/5.9.6
• Transversely stiffened plate panels, with structural behavior given in 5C-5-A4/5.9.7
• Hard corners, as defined below, with structural behavior given in 5C-5-A4/5.9.1

846 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 4 Hull Girder Ultimate Strength Assessment of Container Carriers 5C-5-A4

vi) The following structural areas are to be defined as hard corners:

• The plating area adjacent to intersecting plates
• The plating area adjacent to knuckles in the plating with an angle greater than 30 degrees.
• Plating comprising rounded gunwales
An illustration of hard corner definition for girders on longitudinal bulkheads is given in
5C-5-A4/Figure 3.
vii) The size and modeling of hard corner elements is to be as follows:
• It is to be assumed that the hard corner extends up to s/2 from the plate intersection for
longitudinally stiffened plate, where s is the stiffener spacing
• It is to be assumed that the hard corner extends up to 20tgrs from the plate intersection for
transversely stiffened plates, where tgrs is the gross plate thickness.
Note: For transversely stiffened plate, the effective breadth of plate for the load shortening portion of the stress-strain
curve is to be taken as the full plate breadth, i.e., to the intersection of other plates – not from the end of the hard
corner. The area is to be calculated using the breadth between the intersecting plates.

FIGURE 3
Example of Defining Structural Elements (2010)
a) Example showing side shell, inner side and deck

Longitudinal
stiffener elements
Hard corner
elements

b) Example showing girder on longitudinal bulkhead

Longitudinal
stiffener elements

Hard corner
element

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 847
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 4 Hull Girder Ultimate Strength Assessment of Container Carriers 5C-5-A4

5.9 Stress-strain Curves σ-ε (or Load-end Shortening Curves)

5.9.1 Hard Corners
Hard corners are sturdier elements which are assumed to buckle and fail in an elastic, perfectly
plastic manner. The relevant stress strain curve σ-ε is to be obtained for lengthened and shortened
hard corners according to 5C-5-A4/5.9.2.
5.9.2 Elasto-Plastic Failure of Structural Elements
The equation describing the stress-strain curve σ-ε of the elasto-plastic failure of structural
elements is to be obtained from the following formula, valid for both positive (compression or
shortening) of hard corners and negative (tension or lengthening) strains of all elements (see
5C-5-A4/Figure 4):
σ = Φ σyd kN/cm2 (kgf/cm2)
where
Φ = edge function
= –1 for ε < –1
= ε for –1 < ε < 1
= 1 for ε > 1
ε = relative strain
εE
=
ε yd

εE = element strain
εyd = strain corresponding to yield stress in the element
σ yd
=
E
Note: The signs of the stresses and strains in this Appendix are opposite to those in the rest of the Rules.

FIGURE 4
Example of Stress Strain Curves σ-ε (2010)
a) Stress strain curve σ-ε for elastic, perfectly plastic failure of a hard corner
σ

σyd

compression or
shortening

tension or
lengthening

−σyd

848 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 4 Hull Girder Ultimate Strength Assessment of Container Carriers 5C-5-A4

FIGURE 4 (continued)
Example of Stress Strain Curves σ-ε (2010)
b) Typical stress strain curve σ-ε for elasto-plastic failure of a stiffener
σ

σyd

compression or
shortening
ε

tension or
lengthening

−σyd

5.9.3 Beam Column Buckling

The equation describing the shortening portion of the stress strain curve σCR1-ε for the beam
column buckling of stiffeners is to be obtained from the following formula:
⎛ As + beff − p t p ⎞
σ CR1 = Φσ C1 ⎜ ⎟ kN/cm2 (kgf/cm2)
⎜ As + st p ⎟
⎝ ⎠
where
σC1 = critical stress, in kgf/cm2 (kgf/cm2)

σ E1 σ yd
= for σE1 ≤ ε
ε 2
⎛ σ yd ε ⎞ σ yd
= σ yd ⎜⎜1 − ⎟ for σE1 > ε
⎝ 4σ E1 ⎟⎠ 2

σE1 = Euler column buckling stress, in kgf/cm2 (kgf/cm2)

IE
= π 2E
AE l 2

l = unsupported span of the longitudinal, in cm

s = plate breadth taken as the spacing between the stiffeners, in cm
IE = net moment of inertia of stiffeners, in cm4, with attached plating of width beff-s
beff-s = effective width, in cm, of the attached plating for the stiffener

s
= for βp > 1.0
βp

= s for βp ≤ 1.0

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 849
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 4 Hull Girder Ultimate Strength Assessment of Container Carriers 5C-5-A4

s εσ yd
βp =
tp E

AE = net area of stiffeners, in cm2, with attached plating of width beff-p

beff-p = effective width, in cm, of the plating

⎛ 2.25 1.25 ⎞
= ⎜ − 2 ⎟s for βp > 1.25
⎜ βp β p ⎟⎠
⎝
= s for βp ≤ 1.25

5.9.4 Torsional Buckling of Stiffeners

The equation describing the shortening portion of the stress-strain curve σCR2-ε for the lateral-
flexural buckling of stiffeners is to be obtained according to the following formula:
⎛ As σ C 2 + st p σ CP ⎞
σ CR 2 = Φ⎜ ⎟ kN/cm2 (kgf/cm2)
⎜ As + st p ⎟
⎝ ⎠
where
σC2 = critical stress

σ E2 σ yd
= for σE2 ≤ ε
ε 2
⎛ σ yd ε ⎞ σ yd
= σ yd ⎜⎜1 − ⎟ for σE2 > ε
⎝ 4σ E 2 ⎟⎠ 2

σCP = ultimate strength of the attached plating for the stiffener

⎛ 2.25 1.25 ⎞
= ⎜ − 2 ⎟σ yd for βp > 1.25
⎜ βp β p ⎟⎠
⎝
= σyd for βp ≤ 1.25

βp = coefficient defined in 5C-5-A4/5.9.3

σE2 = Euler torsional buckling stress, in kN/cm2 (kgf/cm2), equal to reference
stress for torsional buckling σET
σET = E[K/2.6 + (nπ/l)2Γ + Co(l/nπ)2/E]/Io[1 + Co(l/nπ)2/Io fcL]
K = St. Venant torsion constant for the longitudinal’s cross section, excluding the
associated plating

= [b t f
3
f ]
+ d w t w3 / 3

Io = polar moment of inertia of the longitudinal, excluding the associated plating,

about the toe (intersection of web and plating)

= Ix + mIy + As x o2 + y o2 ( ) in cm4
Ix, Iy = moment of inertia of the longitudinal about the x- and y-axis, respectively,
through the centroid of the longitudinal, excluding the plating (x-axis
perpendicular to the web), in cm4
m = 1.0 − u(0.7 − 0.1dw/bf)

850 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 4 Hull Girder Ultimate Strength Assessment of Container Carriers 5C-5-A4

u = unsymmetry factor
= 1 − 2b1/bf

Co = E t 3p /3s

Γ = warping constant

≅ mIyf d w2 + d w3 t w3 /36

Iyf = tf b 3f (1.0 + 3.0 u2dwtw/As)/12

fcL = critical buckling stress for the associated plating, corresponding to n-half
waves
= π2E(n/α + α/n)2(tp/s)2/12(1 − ν2)
α = l/s
l = unsupported span of the longitudinal, in cm
s = plate breadth taken as the spacing between the stiffeners, in cm
n = number of half-wave which yield a smallest σET

5.9.5 Web Local Buckling of Stiffeners with Flanged Profiles

The equation describing the shortening portion of the stress strain curve σCR3-ε for the web local
buckling of flanged stiffeners is to be obtained from the following formula:
⎛ beff − p t p + d w−eff t w + b f t f ⎞
σ CR 3 = Φσ yd ⎜ ⎟ kN/cm2 (kgf/cm2)
⎜ st p + d w t w + b f t f ⎟
⎝ ⎠
where
s = plate breadth taken as the spacing between the stiffeners, in cm
beff-p = effective width of the attached plating in cm, defined in 5C-5-A4/5.9.3
dw-eff = effective depth of the web, in cm

⎛ 2.25 1.25 ⎞
= ⎜ − 2 ⎟d w for βw > 1.25
⎜ β
⎝ w β w ⎟⎠
= dw for βw ≤ 1.25

dw εσ yd
βw =
tw E

5.9.6 Local Buckling of Flat Bar Stiffeners

The equation describing the shortening portion of the stress-strain curve σCR4-ε for the web local
buckling of flat bar stiffeners is to be obtained from the following formula:
⎛ As σ C 4 + st p σ CP ⎞
σ CR 4 = Φ⎜ ⎟ kN/cm2 (kgf/cm2)
⎜ As + st p ⎟
⎝ ⎠
where
σCP = ultimate strength of the attached plating, in kN/cm2 (kgf/cm2)

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 851
Part 5C Specific Vessel Types
Chapter 5 Vessels Intended to Carry Containers (130 m (427 ft) to 450 m (1476 ft) in Length)
Appendix 4 Hull Girder Ultimate Strength Assessment of Container Carriers 5C-5-A4

σC4 = critical stress, in kN/cm2 (kgf/cm2)

σ E4 σ yd
= for σE4 ≤ ε
ε 2
⎛ σ yd ε ⎞ σ yd
= σ yd ⎜⎜1 − ⎟ for σE4 > ε
⎝ 4σ E 4 ⎟⎠ 2

σE4 = Euler buckling stress

2
0.44π 2 E ⎛ t w ⎞
⎜ ⎟
=
( )
12 1 − ν 2 ⎜⎝ d w ⎟
⎠

5.9.7 Buckling of Transversely Stiffened Plate Panels

The equation describing the shortening portion of the stress-strain curve σCR5-ε for the buckling of
transversely stiffened panels is to be obtained from the following formula:
⎧ ⎡ ⎛ 2.25 1.25 ⎞ ⎞ ⎤
2
⎪σ ⎢ s ⎛ s ⎞⎛ 1
⎪ yd ⎜ ⎟
− 2 + 0.115⎜1 − ⎜
⎟ 1+ ⎟ ⎥
σ CR 5 = min ⎨ ⎢ l stf ⎜ βp βp ⎠⎟ ⎜ l ⎟⎜
stf ⎠⎝
2 ⎟ ⎥ kN/cm2 (kgf/cm2)
βp ⎠
⎢⎣ ⎝ ⎝ ⎥⎦
⎪
⎪⎩σ yd Φ

where
βp = coefficient defined in 5C-5-A4/5.9.3
s = plate breadth taken as the spacing between the stiffeners, in cm
lstf = span of stiffener equal to spacing between primary support members, in cm

852 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
PART Chapter 6: Vessels Intended to Carry Containers (Under 130 meters (427 feet) in Length)

5C
CHAPTER 6 Vessels Intended to Carry Containers (Under 130
meters (427 feet) in Length)

CONTENTS
SECTION 1 Introduction ........................................................................................ 854
1 General ...........................................................................................854
1.1 Classification ............................................................................... 854
1.3 Application................................................................................... 854
1.5 Arrangement................................................................................ 854
1.7 Submission of Plans .................................................................... 854
3 Definitions .......................................................................................854
3.1 Freeboard Deck........................................................................... 854

SECTION 2 Hull Structure ..................................................................................... 855

1 Hull Girder Strength ........................................................................855
1.1 Normal-strength Standard ........................................................... 855
1.3 Hull Girder Shear and Bending Moment...................................... 855
1.5 Torsion and Horizontal Bending .................................................. 855
1.7 Loading Guidance ....................................................................... 855
1.9 Continuous Longitudinal Deck Structures Between Hatch
Openings ..................................................................................... 855
3 Local Strength.................................................................................855
3.1 Double Bottom............................................................................. 855
3.3 Container Loading ....................................................................... 855
3.5 Securing Arrangement................................................................. 855
3.7 Hatchway Closures ..................................................................... 855

SECTION 3 Cargo Safety ....................................................................................... 856

APPENDIX 1 Guide for Strength Assessment of Container Carriers – Vessels

Under 130 meters (427 feet) in Length ............................................. 857
1 Note.................................................................................................857
3 Application ......................................................................................857
5 Hull Girder Longitudinal Strength....................................................857
5.1 Check Points ............................................................................... 857
5.3 Hull Girder Stress ........................................................................ 858

FIGURE 1 Strength (Upper) Deck ..........................................................861

FIGURE 2 Midship Section.....................................................................862
FIGURE 3 Section Under Consideration ................................................862

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 853
PART Section 1: Introduction

5C
CHAPTER 6 Vessels Intended to Carry Containers (Under 130
meters (427 feet) in Length)

SECTION 1 Introduction

1 General

1.1 Classification
In accordance with 1-1-3/3, the classification À A1 Container Carrier is to be assigned to vessels built
to the requirements of this Chapter and other relevant Sections of the Rules.

1.3 Application
The requirements in this Chapter are applicable to vessels designed primarily for the carriage of containers
in holds or on deck, or both, with structures for that purpose, such as cell guides, pedestals, etc.

1.5 Arrangement
Strength bulkheads or combined deep webs and substantial partial bulkheads are to be provided in
accordance with 3-2-9/1.7. Upper wing torsional boxes or double hull side construction are to be provided
in way of container holds having wide deck openings.

1.7 Submission of Plans

In addition to the plans listed elsewhere in the Rules, the following plans are to be submitted. See Section
1-1-7.
Stowage arrangement of containers including stacking loads. Location of container supports and their
connection to hull.

3 Definitions

3.1 Freeboard Deck

For the purpose of this Part, freeboard deck may be taken as the lowest actual deck from which the draft
can be obtained under the International Load Line Regulations.

854 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
PART Section 2: Hull Structure

5C
CHAPTER 6 Vessels Intended to Carry Containers (Under 130
meters (427 feet) in Length)

SECTION 2 Hull Structure

1 Hull Girder Strength

1.1 Normal-strength Standard

The longitudinal hull girder strength is to be required by the equations given in Section 3-2-1.

1.3 Hull Girder Shear and Bending Moment

For shear and bending-moment calculation requirements, see Section 3-2-1.

1.5 Torsion and Horizontal Bending

The hull girder strength calculations under combined vertical and horizontal bending moment and torsion
are to be submitted. ABS Guide for Strength Assessment of Container Carriers (Appendix 5C-6-A1) provides
guidance in performing this calculation. A more comprehensive analysis will also be acceptable.

1.7 Loading Guidance

Loading guidance is to be as required by 3-2-1/7.

1.9 Continuous Longitudinal Deck Structures Between Hatch Openings

The degree of effectiveness of continuous longitudinal deck structures between hatch openings is to be
determined in accordance with 3-2-1/17.3.

3 Local Strength

3.1 Double Bottom

Structures under base sockets are to be reinforced to withstand the anticipated load. An engineering
analysis for the double bottom structure may be required.
In determining the scantlings of inner bottom longitudinals and bottom longitudinals with struts, reduced
length permitted for uniformly loaded inner bottom is not to be used.

3.3 Container Loading

Deck and hatch cover structures supporting containers are to have scantlings, as required by 3-2-7/5,
3-2-8/1.3 and 3-2-15/9.9. See also 3-2-15/5.5 for chocks and pads on hatch coaming.

3.5 Securing Arrangement

When requested, the container securing system may be certified in accordance with the ABS Guide for
Certification of Container Securing Systems. Additional plans and calculations as required in that Guide
are to be submitted.

3.7 Hatchway Closures

For gasketless hatch covers, see 3-2-15/11.1. Vessels without hatch covers will be specially considered.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 855
PART Section 3: Cargo Safety

5C
CHAPTER 6 Vessels Intended to Carry Containers (Under 130
meters (427 feet) in Length)

SECTION 3 Cargo Safety

See Section 5C-5-7.

856 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
PART Appendix 1: Guide for Strength Assessment of Container Carriers – Vessels Under 130 meters (427 feet) in Length

5C
CHAPTER 6 Vessels Intended to Carry Containers (Under 130
meters (427 feet) in Length)

APPENDIX 1 Guide for Strength Assessment of Container

Carriers – Vessels Under 130 meters (427 feet) in
Length

1 Note
The requirements given herein contain equation for warping stress developed from the theory of thin-
walled beams. Equations for horizontal bending stress are also included together with that for combined
stress which is being used as the parameter. The combined stresses, calculated for four designs, were used
in arriving at the acceptance criteria.

3 Application
These criteria are applicable to steel vessels of up to 130 m (427 ft) in length, designed for the carriage of
containers and intended for unrestricted ocean service. The basic structural arrangement consists of a
double bottom with a double skin side structure or a single skin side structure with upper torsion boxes.
In addition to complying with the ABS Rules for Building and Classing Steel Vessels, the strength of the
vessel is to be evaluated using the criteria presented in this Guide.
If the stresses, determined in accordance with this Guide, exceed the permissible value given herein, a
direct calculation stress analysis can be carried out to evaluate the adequacy of the vessel’s structural
design in a more sophisticated manner. On request, this analysis may be carried out by ABS.

5 Hull Girder Longitudinal Strength

5.1 Check Points

The combined longitudinal hull girder stress σ is to be calculated at the inboard edge of the strength
(upper) deck plating at the transverse sections shown on 5C-6-A1/Figure 1:
1 The aft end of the hatch opening immediately forward of the machinery room, (Section No. 1).
2 The forward end of the foremost hatch where there is a change in the width of the hatch, (Section
No. 2).
3 The forward end of the next hatch aft of the section No. 2, (Section No. 3).

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 857
Part 5C Specific Vessel Types
Chapter 6 Vessels Intended to Carry Containers (Under 130 m (427 ft) in Length)
Appendix 1 Guide for Strength Assessment of Container Carriers 5C-6-A1

5.3 Hull Girder Stress

5.3.1 Combined Longitudinal Hull Girder Stress
The combined longitudinal hull girder stress σ at the inboard edge of the strength deck plating is
to be obtained from the following equation:
σ = σs + σv + σH + σT
where
σs = still-water bending component, see 5C-6-A1/5.3.2

σv = vertical wave-induced bending component, see 5C-6-A1/5.3.3

σH = horizontal wave-induced bending component, see 5C-6-A1/5.3.4

σT = warping component, see 5C-6-A1/5.3.5

The calculated longitudinal hull girder stress σ is not to exceed 60% of the minimum specified
yield point or yield strength of the material.
5.3.2 Still-water Bending Component
The still-water bending component is to be obtained from the following equation:
σs = Ms/SM kN/cm2 (tf/cm2, Lft/in2)
where
Ms = still-water bending at the section under consideration for design loading
conditions, in kN-m (ft-m, Ltf-ft)
SM = hull girder section modulus about the horizontal neutral axis at the section
under consideration, in cm2-m (in2-ft)
5.3.3 Vertical Wave-induced Bending Component
The vertical wave-induced bending component is to be obtained from the following equation:
σv = 0.47M · Mwh/SM kN/cm2 (ft/cm2, Ltf/in2)
where
Mwh = wave-induced bending moment amidships, as given in 3-2-1/3.5.1 of the
Rules, in kN-m (tf-m, Ltf-ft)
SM = hull girder section modulus, defined in 5C-6-A1/5.3.2, in cm2-m (in2-ft)
M = distribution factor given by 3-2-1/Figure 2 of the Rules
5.3.4 Horizontal Wave-induced Bending Component
The horizontal wave-induced bending component is to be obtained from the following equation:
0.175M wh bo (1 − 2 x / L )
σH = kN/cm2 (ft/cm2, Ltf/in2)
Iz
where
Mwh = wave-induced bending moment amidships, as given by 3-2-1/3.5.1 of the
Rules, in kN-m (tf-m, Ltf-ft)
L = length of the vessel, as defined in 3-1-1/3.1 of the Rules, in m (ft)
x = distance from amidships to the section under consideration, in m (ft)

858 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 6 Vessels Intended to Carry Containers (Under 130 m (427 ft) in Length)
Appendix 1 Guide for Strength Assessment of Container Carriers 5C-6-A1

bo = width of the strength deck’s hatch opening of the section under consideration,
measured between the inboard edges of the strength deck, (5C-6-A1/Figure 3),
in m (ft)
Iz = hull girder moment of inertia of the section under consideration about the
vertical axis through the centerline of the vessel, in cm2-m2 (in2-ft2)
5.3.5 Warping Component
The warping component is to be obtained from the following equation:

KK 13 NαhL3o Bo (1 − 0.7bo / Bo )(1 − 0.062 K1 C )

σT = kN/cm2 (tf/cm2, Ltf/in2)
Dt (0.45 − 0.4b / B)
where
K = 9.81 if σT in kN/cm2

= 1.0 if σT in tf/cm2

= 21.58 × 10-4 if σT in Ltf/in2

B = breadth of the vessel amidships, as defined in 3-1-1/5 of the Rules, in m (ft)
Bo = breadth of the vessel at the section under consideration, (5C-6-A1/Figure 3),
in m (ft)
D = depth of the vessel amidships, as defined in 3-1-1/7 of the Rules, in m (ft)
h = 0.0124Lo + 4.37Lo/L SI/MKS units (0.124 Lo + 14.34 Lo /L US units)
Lo = length, as shown on 5C-6-A1/Figure 1, measured from the forward engine
room’s bulkhead and the first section of the forward part of the hatch
opening that has hatch width greater than the hatch forward, in m (ft)
K1 = 1.0 for sections Nos. 1 and 2, as defined in 5C-6-A1/5.1

= l/Lo for section No. 3, as defined in 5C-6-A1/5.1

K1 is not to be less than 0.85.

l = distance from the forward engine room bulkhead to the section No. 3, in m (ft)
N for section No. 1
= 2.8 × 10-7, (Cb ≤ 0.65)

= 8(1 _ Cb) × 10-7, (Cb > 0.65)

N for sections Nos. 2 and 3
= 5.6 × 10-7, (Cb ≤ 0.65)

= 16(1 _ Cb) × 10-7, (Cb > 0.65)

Cb = block coefficient at summer load waterline
b = width of the strength deck’s hatch opening amidships, measured between the
inboard edges of the strength deck, (5C-6-A1/Figure 2), in m (ft)
bo = width of the strength deck’s hatch opening of the section under consideration,
measured between the inboard edges of the strength deck, (5C-6-A1/Figure 3),
in m (ft)
t = apparent thickness of the side and bottom structures amidships, in mm (in.)

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 859
Part 5C Specific Vessel Types
Chapter 6 Vessels Intended to Carry Containers (Under 130 m (427 ft) in Length)
Appendix 1 Guide for Strength Assessment of Container Carriers 5C-6-A1

The apparent thickness is the total area of the side and bottom structures (plating and longitudinals)
divided by the combined girth of the side and bottom.
where

C =
[Bd DB + 2 Dd D ]2 L20
B 3 D 2 t (1.67d D / t D + 1.11D / t s + 0.56 B / t B ) (0.45 − 0.4b / B )
dDB = depth of double bottom amidships, (5C-6-A1/Figure 2), in m (ft)
dD = width of the strength deck plating amidships, (5C-6-A1/Figure 2), in m (ft)
tD, ts, tB = mean thickness of the strength deck, side shell, and bottom plating amidships
(inner bottom and longitudinal bulkhead plating are not to be included),
(5C-6-A1/Figure 2), in mm (in.)
α = a B1/Bo + c
B1 = width of the section under consideration at a height of D/2, as shown on
5C-6-A1/Figure 3, in m (ft)
a and c are coefficients, as given in the following table:

Coefficient Coefficient
Section Number per 5C-6-A1/5.1 a c
1 2 -1.45
2 0.53 -0.02
3 0.33 0.05

860 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
Part 5C Specific Vessel Types
Chapter 6 Vessels Intended to Carry Containers (Under 130 m (427 ft) in Length)
Appendix 1 Guide for Strength Assessment of Container Carriers 5C-6-A1

FIGURE 1
Strength (Upper) Deck

L
C

C
Number of section for
stress calculation
Ship A

Ship B

2
bo / 2
2
bo / 2

Lo

3
Lo

1
1

Machinery
Machinery

Room
Room

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 861
Part 5C Specific Vessel Types
Chapter 6 Vessels Intended to Carry Containers (Under 130 m (427 ft) in Length)
Appendix 1 Guide for Strength Assessment of Container Carriers 5C-6-A1

FIGURE 2 FIGURE 3
Midship Section Section Under Consideration
dD
Bo / 2

tD
D/2

bo / 2
b/2 tS

B1 / 2
D/2

dDB

tB

862 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
PART Appendix 1: Guide for SafeHull Construction Monitoring Program

5C
APPENDIX 1 Guide for SafeHull Construction Monitoring
Program (1 July 2001)

1 Introduction
The structural strength criteria specified in the ABS Rules are used by designers to establish acceptable
scantlings in order that a vessel constructed to such standards and properly maintained will have adequate
durability and capability to resist the failure modes of yielding, buckling and fatigue.
The application of SafeHull and other review techniques to assess a design for compliance with Rule
criteria also gives the designer and ABS the ability to identify areas that are considered critical to
satisfactory in-service performance.
Knowing that the actual structural performance is also a function of construction methods and standards, it
is prudent to identify ‘critical’ areas, particularly those approaching design limits, and use appropriate
specified construction quality standards and associated construction monitoring and reporting methods to
limit the risk of unsatisfactory in-service performance.
Accordingly, this Guide defines what is meant by critical areas, describes how they are to be identified and
recorded, delineates what information the shipyard is to include in the construction monitoring plan and
lays out the certification regime to be followed.

3 Application
Vessels designed and reviewed to Part 5C, Chapters 1, 3 and 5 of the ABS Rules are to comply with the
requirements of this Guide and have the notation SH, SHCM. Other vessel types may be considered on a
case by case basis.

5 Critical Area
The term critical area, as used in this Guide, is defined as an area within the structure that may have a
higher probability of failure during the life of the vessel compared to the surrounding areas, even though
they may have been modified in the interest of reducing such probability. The higher probability of failure
can be a result of stress concentrations, high stress levels and high stress ranges due to loading patterns,
structural discontinuities or a combination of these factors.
In order to provide an even greater probability of satisfactory in-service performance, the areas that are
approaching the acceptance criteria can be identified so that additional attention may be paid during
fabrication.
The objective of heightened scrutiny of building tolerance and monitoring in way of the critical areas is to
minimize the effect of stress increases incurred as a result of the construction process. Improper alignment
and fabrication tolerances may be potentially influential in creating construction-related stress.

ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012 863
Part 5C Specific Vessel Types
Appendix 1 Guide for SafeHull Construction Monitoring Program 5C-A1

7 Determination of Critical Areas

Critical areas can be determined in a number of ways, including but not limited to:
i) The results of engineering strength and fatigue analyses, such as specified in the ABS Rules
Section 5C-1-5, 5C-3-5 or 5C-5-5 (SafeHull), Finite Element Analysis or a Dynamic Loading
Approach analysis, particularly for areas approaching the allowable criteria.
ii) The application of ABS Rules, such as 3-1-2/15.3.
iii) Details where fabrication is difficult, such as blind alignment, complexity of structural details and
shape, limited access, etc.
iv) Input from owners, designers and/or shipyards based on previous in-service experience from
similar vessels, such as corrosion, wear and tear, etc.

9 Construction Monitoring Plan

A Construction Monitoring Plan for critical areas is to be prepared by the shipyard and submitted for
approval prior to the start of fabrication. The plan is to include:
i) Structural drawings indicating the location of critical areas as identified by the ABS review (see
5C-A1/7).
ii) Construction standards and control procedures to be applied.
iii) Verification and recording procedures at each stage of construction, including any proposed
nondestructive testing.
iv) Procedures for defect correction.
An approved copy of the Construction Monitoring plan is to be placed onboard the vessel.

11 Surveys After Construction

To monitor critical areas during service, an approved copy of the Construction Monitoring Plan should be
available for all subsequent surveys.

13 Notation
Vessels having been found in compliance with the requirements of this Guide may be distinguished in the
Record with the notation SH, SHCM.

864 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012
PART Appendix 2: Guide for ABS Construction Monitoring Program

5C
APPENDIX 2 Guide for ABS Construction Monitoring Program
(1 April 2006)

(This Appendix applies to Part 5A and Part 5B of the Rules for Building and Classing Steel
Vessels for the class notation, CSR, AB-CM.)

1 Introduction
The structural strength criteria specified in the ABS Rules are used by designers to establish acceptable
scantlings in order that a vessel constructed to such standards and properly maintained will have adequate
durability and capability to resist the failure modes of yielding, buckling and fatigue.
The application of Part 5A “Common Structural Rules for Double Hull Oil Tankers”, Part 5B “Common
Structural Rules for Bulk Carriers” and other review techniques to assess a design for compliance with
Rule criteria also gives the designer and ABS the ability to identify areas that are considered critical to
satisfactory in-service performance.
Knowing that the actual structural performance is also a function of construction methods and standards, it
is prudent to identify ‘critical’ areas, particularly those approaching design limits, and use appropriate
specified construction quality standards and associated construction monitoring and reporting methods to
limit the risk of unsatisfactory in-service performance.
Accordingly, this Guide defines what is meant by critical areas, describes how they are to be identified and
recorded, delineates what information the shipyard is to include in the construction monitoring plan and
lays out the certification regime to be followed.

3 Application
Vessels designed and reviewed to Part 5A and Part 5B of the ABS Rules are to comply with the
requirements of this Guide and have the notation CSR, AB-CM.

5 Critical Area
The term critical area, as used in this Guide, is defined as an area within the structure that may have a
higher probability of failure during the life of the vessel compared to the surrounding areas, even though
they may have been modified in the interest of reducing such probability. The higher probability of failure
can be a result of stress concentrations, high stress levels and high stress ranges due to loading patterns,
structural discontinuities or a combination of these factors.
In order to provide an even greater probability of satisfactory in-service performance, the areas that are
approaching the acceptance criteria can be identified so that additional attention may be paid during
fabrication.
The objective of heightened scrutiny of building tolerance and monitoring in way of the critical areas is to
minimize the effect of stress increases incurred as a result of the construction process. Improper alignment
and fabrication tolerances may be potentially influential in creating construction-related stress.

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Part 5C Specific Vessel Types
Appendix 2 Guide for ABS Construction Monitoring Program 5C-A2

7 Determination of Critical Areas

Critical areas can be determined in a number of ways, including but not limited to:
i) The results of engineering strength and fatigue analyses, such as specified in the ABS Rules
Section 5A-9 or Chapters 5B-7 and 5B-8, particularly for areas approaching the allowable criteria.
ii) The application of ABS Rules, such as 3-1-2/15.3 and Section 5A-4-3/2.
iii) Details where fabrication is difficult, such as blind alignment, complexity of structural details and
shape, limited access, etc.
iv) Input from owners, designers and/or shipyards based on previous in-service experience from
similar vessels, such as corrosion, wear and tear, etc.

9 Construction Monitoring Plan

A Construction Monitoring Plan for critical areas is to be prepared by the shipyard and submitted for
approval prior to the start of fabrication. The plan is to include:
i) Structural drawings indicating the location of critical areas as identified by the ABS review (see
5A/5B-A1/7).
ii) Construction standards and control procedures to be applied.
iii) Verification and recording procedures at each stage of construction, including any proposed
nondestructive testing.
iv) Procedures for defect correction.
An approved copy of the Construction Monitoring plan is to be placed onboard the vessel.

11 Surveys After Construction

To monitor critical areas during service, an approved copy of the Construction Monitoring Plan should be
available for all subsequent surveys.

13 Notation
Vessels having been found in compliance with the requirements of this Guide may be distinguished in the
Record with the notation CSR, AB-CM.

866 ABS RULES FOR BUILDING AND CLASSING STEEL VESSELS . 2012