The list of major jobs to be carried out during dry docking are as under:

1. BOTTOM INSPECTION AND CORRECTIVE ACTION AS

RECOMMENDED BY CLASSIFICATION SOCIETY SURVEYOR.
The first visit of the surveyor on the ship. This inspection is carried out and
the dock is dry with the ship's bottom scraped free of barnacle growth.
This inspection is usually carried out during daylight hours especially after
daybreak. In case the ship docks late in the night the following morning.
The attending superintendent along with Master C/E, C/O & 2/O will enter
the dock and go around the ship from forward to aft. The yard attending
repair manager will also be present during this inspection.

This general inspection and any noticeable defects will be further

examined and corrective action taken accordingly. Normally the defects
noticed are of two types,

(a) Dents which are deep and spread over a small area are further
examined internally to note the extent of damages to stiffeners
fitted internally so that the damaged portion of the stiffeners are
renewed along with the dented shell plating

(b) Areas of shell plating which have eroded and wasted badly are to
be gauged and if needed renewed to the extent required.

2. BOTTOM PREPARATION AND PAINTING AS PER COMPANY'S

PAINTING SPECIFICATIONS

This is the first objective in drydocking commences on the first day and
continues till almost to the last day in dry dock. On the first day, the areas
requiring grit blasting are decided by the superintendent in consultation
with the paint suppliers technical officer and yard's painting department
manager. The areas where heavy grit blasting are required on an average
are as follows:

(a)Topside about 40% of the total top side area. After grit blasting two
coats of primer paint put each coat 30 microns.

(b) The boot top about 60% the total belt area consisting of the wind and
weather strakes extending from summer load line to LWL. After grit
blasting to apply two coats of primer paint each coat 40 microns thick.

(c) On the bottom side the grit blasting area is negligible and at the most
does not exceed about 5%. Two coats of primer paint must be applied to
the blasted areas.

(d) The full painting specification now as an example is as follows

Topside- Two coats primer paint each coat 40 microns thick and two
coats finish paint 40 microns thick, each coat.

Boot Top- Two coats primer paint each coat 40 microns thick, two coats
finish paint, each coat 40 microns thick. Antifouling paint one coat each.
 Bottom- Two coat primer paint 40 microns thick each coat. Two coats
finish paint 40 microns thick each coat. One coat antifouling paint 40
microns thick .

During the painting process, the paint suppliers technical officer checks
the coating thickness using a paint thickness gauge which is a strip of
plating about 3mm thick with marking which whilst scrapping the half-
dried paint indicates the thickness by the thickness noted on the plate
gauge. The paint is applied by airless spray nozzles. The Technical officers
also inspect the blasted strakes before the primer paint is applied.

3. ANCHOR CABLES RANGING AND CALIBRATION

Both the anchors along with their cables are lowered into the dock bottom
and the chains are ranged to enable the chains are ranged to enable the
chains to be calibrated. The diameters of the links are checked and noted
and shown to the surveyor. Links on any chain length which have wasted
are discarded by renewing the chain length. The ship always carries one
spare length as per regulations. This length is attached to either the port
or starboard anchors. It is a good practice to turn the chains end to end at
each drydocking so that the link wear is uniform.

CLEANING AND PAINTING OF CHAIN LOCKER

The chain wells are cleaned of mud and accumulated water and painted
with a slow drying chlorinated rubber based paint. This work can only be
done in dry dock since the anchors and chains are taken out into dry
dock.

4. BUILDING UP THE HAWSE PIPE CAST STEEL COLLARS AT BOTH

ENDS

Due to the frequent rubbing of the chain links on the collars during anchor
dropping and heaving up the anchors, the collars get heavily grooved and
if neglected can cause damage to the hawse pipes. Hence this work is
done during dry docking when the hawse pipes are free of the chains

ECHO SOUNDER TRANSDUCERS CLEANING AND CHECKING OF

WATERTIGHT TERMINAL BOXES

The echo sounder are serviced and the cables are checked for continuity
and earth after cleaning the connections in the terminal box. The
transducer plates are cleaned and a coat of fish oil applied on the
transducers.

5. SAL LOG OR DOPPLER SPEED LOG

The ship may be fitted with a Doppler speed log or a Sal log in the case of
older ships. These equipments are to be serviced and calibrated. The dry
docks provides the best situation for verification since any transducers
fitted underwater can be thoroughly checked and renewed if they are
faulty.
6. SACRIFICIAL ZINC ANODES OR IMPRESSED CURRENT SYSTEM

All zinc sacrificial anodes are to be renewed. Most of them would be

completely wasted. If any un-wasted anodes are found they are not of
good quality and hence must be renewed. The number of zinc anodes
should not be reduced as they are calculated as a total quantity of zinc to
be distributed all over the hull surface especially on the bilge keels, the
stern portion and on the rudder, The total mass of zinc used is
proportional to wetted surface area of the ship and the mass of the
propeller If the ship is fitted with an impressed current system then it
must be serviced and calibrated.

7. SEA CHESTS CLEANING AND PAINTING

All ships are fitted with at least three sea chests in the machinery space
area. They are high sea suction, low sea suction and the emergency fire
pump sea suction. Their suction grids are to be dismantled and cleaned.
The internal surface of the chest have to be scraped clean of all growth. In
case of doubt, the casing plate thickness have to be gauged for thickness
and renewed as necessary. After cleaning they are to be painted in
accordance with the ships hull painting specification. Zinc anodes in the
sea chests are to be renewed.

8. SEA SUCTION AND DISCHARGE VALVES OVERHAUL AND SURVEY

All sea suction and discharge valves are to be overhauled at every

drydocking. Every alternate dry docking they are surveyed. The air and
steam connections to the boxes must be checked and any defects also
attended. Many shipping companies also overhaul the main intermediate
valves and attached mud filters.
9. SANITARY STORM VALVES OVERHAUL AND THEIR SURVEY

All storm valves flaps will be dismantled, their leather washer renewed
and defective hinge pins renewed. The soil pipes will be inspected for any
signs of excessive corrosion, cracks and necessary renewals carried out.
The provision of storm valves is a mandatory requirement under LL
Regulations even if the ship is fitted with sewage treatment plant

10.DAMAGED PORTIONS OF BILGE KEELS TO BE RENEWED

11.RUDDER PINTLE CLEARANCES JUMPING CLEARANCE, ANY REPAIRS

AND HYDRAULIC TESTING

The rudder bottom plug is opened out in dry dock. If accumulated water
comes out. It indicates the rudder plating is cracked and hence sea water
has found its way into the rudder making it heavy causing the rudder
movement sluggish. Hence the location of the damage has to be found out
and then suitably repaired. For this, the rudder top plug is opened. The
bottom plug refitted and rudder filled up with water through the top plug.
The location of the damage will be found out by water seen leaking out
from the hole/crack. Suitable repairs can now be carried out and finally,
an hydrostatic test can be carried out by filling water into the
rudder through a flexible rubber tube fitted at the end of the rubber pipe
with the funnel held at the summer load line level. This test proves the
tightness of the repair when the rudder internally is subjected to head of
water up to summer load line. The internal surface of the rudder is painted
by a process of paint displacing the water, whereby the paint resting on
the water surface spreads all around internally whilst the water level is
being lowered through the bottom plug. This method is called the float
coat method using a rubber based paint of lower density and slower
drying rate. All paint manufacturers supplying ship's paints make this kind
of paint.

The pintle bush clearance for the top and bottom pintles are to be
measured using long feeler gauges. The allowable pintle bush clearance is
15 mm for pintle dia. up to 200mm. For dia. exceeding 200mm the
clearance is proportionately increased. If the clearances are excessive the
bushes are to be renewed after dismantling the rudder. The clearances
are taken at the port, starboard, forward and aft and the maximum of
these is the clearance.

The rudder drop is measured using the rudder trammel gauge, but many
ships are not checking the rudder drop since the verification of jumping
clearance gives the same information. The verification of
jumping clearance is carried out by comparing the clearance at the
jumping bar under the rudder skeg with the clearance at the steering gear
X-head. The clearance at the X-head should be more than the jumping
clearance to prevent the X-head interfering with the rams and damaging
the rams. Jumping clearance can be increased by wear of the rudder
pedestal bearings or by the jumping bar falling off the rudder if the
welding holding the bar has given way. If the pedestal bearing has worn
off the rudder is to be jacked up and the pedestal bearing halves
dismantled, the bearing built up by welding and suitably machined.
12.PROPELLER DROP

The propeller drop is taken or measured at every dry docking

irrespective whether the propeller shaft is withdrawn for survey or not
withdrawn. In oil lubricated shaft systems the drop is measured by a
Vernier poker gauge maintained on board and kept with the C/E. This
poker gauge is inserted in the aft seal box through a plug hole provided
for the same and measured from top and bottom plugs.

Propeller polishing and repairs if needed. The propeller blades and boss
are polished using rotary sand diskers so that the small barnacle growth
on the blade surface are polished thereby restoring the original speed.
After polishing a coat of fish oil is applied on the blades. All air cavitation
 pitting craters are filled up utilizing a polymer-based bronze cement and
then polished. Frayed and cracked blade ends are built up by
brazing utilizing compatible bronze alloy filler rods.

13.PROPELLER SHAFT SURVEY IF DUE

The propeller shaft is withdrawn for the survey in accordance with the
following time intervals

(a) Shafts seawater lubricated and having lignum vitae or synthetic fibre
bushes-every four years.

(b) Shafts keyed and oil lubricated with patent seals- every five years.

(c) Shafts keyless and oil lubricated with patent seals-every ten years.

By this arrangement ships having keyed propeller shafts with patent oil
seals will have their shaft withdrawal and survey every alternate
drydocking. Ships having keyless shafts with patent oil seals will have the
shaft withdrawal and survey every fourth drydocking. Ships having water
lubricated shafts and working in synthetic fibre bushes will have their shaft
survey every four years, which may need special dry docking for this
survey or they may be able to adjust the dry docking to ensure that they
comply with the rule requirements.
 Conclusion: The drydocking survey report issued by the surveyor
attending the dry dock will have the following entries, recordings and
suitable notations:

(a) Bottom inspection- date of inspection and any correction work carried
out with the specification of work carried out.
(b) Anchor chain calibration readings and any renewals
(c) Sea valves survey
(d) Storm valves survey
(e) Rudder pintle clearances measurement. If bushes are renewed it will
be recorded.
(f) If rudder pedestal bearing built up and machined it should be recorded.
(g) Propeller drop recorded.

HARMONISED SHIP SURVEY

Harmonized System of Survey and Certification (HSSC) was brought about with the sole
objective of simplifying and systemizing the survey and certification of ships. This will ensure
that survey works will not be duplicated e.g. survey for load line or cargo ship safety
construction is more or less same with logical changes.

If a ship undergoes survey of one, the survey of other will only overlap and once conducted
can be valid for both. Needless to say, a single survey covering both certifications will save a
lot of time and money. This will also allow the ship to plan the survey in a more relaxed
and professional manner.

The total number of surveys will be reduced and maintenance and work on board will be
more systematic and ships will not be out of service at different times for different surveys.

Harmonized System of Survey and Certification (HSSC) covers the

following certification under the modified or amended instruments:
1. SOLAS 1974 as modified by its 1988 protocol
2. LLC 1966 as modified by its 1988 protocol
3. MARPOL 1973 and 1978 as amended by 1990 resolution (MARPOL 73/78/90)
4. IBC Code
5. IGC Code
6. BCH Code

It covers the following certificates:

1. Cargo Ship Safety Equipment Certificate

2. Cargo Ship Safety Construction Certificate
3. Cargo Ship Safety Radio Certificate
4. International Load Line Certificate
5. International Oil Pollution Prevention Certificate
6. International Pollution Prevention Certificate for Carriage of Noxious Liquid Substances
in Bulk
7. International Sewage Pollution Prevention Certificate
8. International Air Pollution Prevention Certificate
9. International Certificate of Fitness for the Carriage of Dangerous Chemicals in Bulk or
the Certificate of Fitness for the Carriage of Dangerous Chemicals in Bulk
10. International Certificate of Fitness for the Carriage of Liquefied Gases in Bulk
11. Passenger Ship Safety Certificate

Surveys for the issuance of these certificates, under the SOLAS, MARPOL, the Load Line
Convention and the Gas and Chemical Tanker Codes are as follows:

Types of Ship Survey

Initial survey
The initial survey should include a complete inspection, with tests when necessary, of the
structure, machinery, and equipment to ensure that the requirements relevant to the
particular certificate are complied with and that the structure, machinery, and equipment are
fit for the service for which the ship is intended.

The initial survey should consist of:

1. an examination of the plans, diagrams, specifications, calculations and other technical

documentation to verify that the structure, machinery, and equipment comply with the
requirements relevant to the particular certificate.
2. an inspection of the structure, machinery and equipment to ensure that the materials,
scantlings, construction and arrangements, as appropriate, are in accordance with the
approved plans, diagrams, specifications, calculations and other technical
documentation and that the workmanship and installation are in all respects satisfactory;
and
3. a check that all the certificates, record books, operating manuals and other instructions
and documentation specified in the requirements relevant to the particular certificate
have been placed on board the ship.

Annual survey
General inspection of the items relating to the particular certificate to ensure that they have
been maintained and remain satisfactory for the service for which the ship is intended in
accordance with the relevant requirements. The annual survey, as required by the relevant
regulations should be held within three months before or after each anniversary date of the
certificate.

The scope of the annual survey should be as follows:

1. it should consist of a certificate examination, a visual examination of a sufficient extent of

the ship and its equipment, and certain tests to confirm that their condition is being
properly maintained;
2. it should also include a visual examination to confirm that no unapproved modifications
have been made to the ship and its equipment;
3. the content of each annual survey is given in the respective guidelines. The
thoroughness and stringency of the survey should depend upon the condition of the ship
and its equipment; and
4. should any doubt arise as to the maintenance of the condition of the ship or its
equipment, further examination and testing should be conducted as considered
necessary.

Intermediate survey
The intermediate survey should be an inspection of items relevant to the particular certificate
to ensure that they are in a satisfactory condition and are fit for the service for which the ship
is intended.

The intermediate survey, as required by the relevant regulations should be held within three
months before or after the second anniversary date or within three months before or after the
third anniversary date of the appropriate certificate and should take the place of one of the
annual surveys.

Periodical survey
Inspection of the items relating to the particular certificate to ensure that they are in a
satisfactory condition and fit for the service for which the ship is intended. The periodical
survey should also consist of a check that all the certificates, record books, operating
manuals and other instructions and documentation specified in the requirements relevant to
the particular certificate are on board the ship.

The periodical survey, as required by the relevant regulations should be held within three
months before or after the second anniversary date or within three months before or after the
third anniversary date in the case of the cargo ship safety equipment certificate and should
take the place of one of the annual surveys and within three months before or after each
anniversary date in the case of the cargo ship safety radio certificate.

Renewal survey
As per periodical survey but leads to the issue of a new certificate and to be held before the
appropriate certificate is renewed.

he cargo ship safety construction renewal survey may be commenced at the fourth annual
survey and may be progressed during the succeeding year with a view to completion by the
fifth anniversary date. The survey items of the fourth annual survey should not be credited
to the completion of the renewal survey.

The renewal survey should consist of:

1. an inspection, with tests when necessary, of the structure, machinery, and equipment to
ensure that the requirements relevant to the particular certificate are complied with and
that they are in a satisfactory condition and are fit for the service for which the ship is
intended.
2. also consist of a check that all the certificates, record books, operating manuals and
other instructions and documentation specified in the requirements relevant to the
particular certificate are on board the ship.
3. Concurrent crediting to both intermediate and renewal safety construction survey for
surveys of spaces should not be acceptable.

The harmonized system provides for:

One year standard interval between surveys, based on initial, annual,
intermediate, periodical and renewal surveys as appropriate. A scheme for providing the
necessary flexibility for the execution of each survey with the provision that:

1. the renewal survey may be completed within 3 months before the expiry date of
the existing certificate with no loss of the period of validity.
2. there is a “window period” of 6 months, from 3 months before to 3 months after
the anniversary date of the certificate for annual, intermediate and periodical surveys.

 A maximum period of validity of 5 years for all certificates for cargo ships
 A maximum period of validity of 12 months for the Passenger Ship Safety Certificate
 A system for the extension of certificates limited to 3 months to enable a ship
to complete its voyage or one month for ships engaged on short voyages
 The period of validity of the new certificate starts from the expiry of the existing certificate
before its extension if the extension was granted