2017

Report – mooring analysis

La Manga

Site: La Manga
Document number: FR-12023-0189
Revision: 1

- - Ref.
Reliability class: - -
Meets requirements in NS9415:2009 and NYTEK: No Table 1
 Report – Mooring analysis La Manga
FR-12023-0189, rev. 1

Report title: Mooring analysis La Manga

Site name: Site number: Municipality: State/Country:

La Manga - Guaymas Sonora, Mexico

Contracting authority: VAT no.: Contact person: Client number:

Erling Haug AS 984706146 Robert Pevik 12023

Date of release: Author: Controlled by: Number of pages:

19.06.2017 Thomassen - 36

Rev.: 1 Date of revision: Revision by: Controlled by:

Replaces: 0 20.06.2017 Thomassen López

Report number: Project number: Order number: Do not distribute

FR-12023-0189 0189 0390 without permission
from the client or
Akvasafe AS

Summary:
Please, refer to Table 1.

Akvasafe AS
Address: Espehaugen 41, Pb. 175 Blomsterdalen, 5868 Bergen, Norway
VAT number: 997935187
Website: www.akvasafe.no
e-mail: ingve@akvasafe.no
Telephone: 468 12 632

1
Akvasafe AS Tel.: 468 12 632 www.akvasafe.no
Espehaugen 41, Pb. 175 Blomsterdalen Epost: ingve@akvasafe.no Dok-ID: V6.9.05, rev K
5868 Bergen, Norway Org.nr.: NO 997935187 MVA
 Report – Mooring analysis La Manga
FR-12023-0189, rev. 1

1 Table of contents
1 Table of contents ............................................................................................................................... 2
2 Figure List ........................................................................................................................................... 3
3 Table List ............................................................................................................................................ 3
4 Summary ............................................................................................................................................ 5
5 Site information ................................................................................................................................. 7
6 Description of main components....................................................................................................... 9
6.1 Introduction ............................................................................................................................... 9
6.2 Mooring.................................................................................................................................... 10
6.2.1 Frame and bridles ............................................................................................................ 10
6.2.2 Anchor lines ..................................................................................................................... 12
6.2.3 Buoys ................................................................................................................................ 13
6.3 Floating collar........................................................................................................................... 14
6.4 Nets .......................................................................................................................................... 14
7 Analysis Tools ................................................................................................................................... 15
8 Model ............................................................................................................................................... 16
9 Load cases ........................................................................................................................................ 18
9.1 Introduction ............................................................................................................................. 18
9.2 Serviceability limit state ........................................................................................................... 19
9.3 Ultimate limit state (ULS) ......................................................................................................... 19
9.4 Accidental limit state (ALS) ...................................................................................................... 19
9.5 Fatigue limit state (FLS)............................................................................................................ 19
9.6 Load factors and load combinations used in the analyses ...................................................... 20
10 Results .............................................................................................................................................. 21
10.1 Static equilibrium – pretension................................................................................................ 21
10.2 Ultimate limit state (ULS) ......................................................................................................... 21
10.2.1 Discussion......................................................................................................................... 24
10.3 Accidental limit state (ALS) ...................................................................................................... 25
10.3.1 Introduction ..................................................................................................................... 25
10.3.2 Spring tide ........................................................................................................................ 28
10.3.3 Punctures ......................................................................................................................... 28
10.4 Fatigue limit state (FLS)............................................................................................................ 29
10.5 Anchor points ........................................................................................................................... 30
10.6 Forces acting on the floating collars ........................................................................................ 31
10.7 Buoy forces .............................................................................................................................. 32
10.8 Mooring requirements............................................................................................................. 34
11 Conclusion ........................................................................................................................................ 36
12 References ....................................................................................................................................... 36

2
Akvasafe AS Tel.: 468 12 632 www.akvasafe.no
Espehaugen 41, Pb. 175 Blomsterdalen Epost: ingve@akvasafe.no Dok-ID: V6.9.05, rev K
5868 Bergen, Norway Org.nr.: NO 997935187 MVA
 Report – Mooring analysis La Manga
FR-12023-0189, rev. 1

2 Figure List
Figure 1: Detailed map of the fish farm with mooring .............................................................................. 8
Figure 2: Location of the fish farm ............................................................................................................. 8
Figure 3: Mooring with numbered lines .................................................................................................... 9
Figure 4: Positioning of the buoys and cages in the fish farm ................................................................. 10
Figure 5: Specification from customer ..................................................................................................... 14
Figure 6: Example of a flow profile with two different flow rates ........................................................... 15
Figure 7: View of the model ..................................................................................................................... 16
Figure 8: Behaviour of the bottom chain with (above) and without (below) contact with the seabed.. 16
Figure 9: Net model ................................................................................................................................. 17
Figure 10: Pretension with static equilibrium .......................................................................................... 21
Figure 11: Analysis 12 of 16 produces the highest load in lines 3b, bridle 102 and in frame B1-B2 (ULS)
................................................................................................................................................................. 22
Figure 12: Analysis 6 of 16 produces the highest loads in the North-eastern lines (ULS) ....................... 23
Figure 13: Analysis 12 of 16 produces the highest loads in bridle 102 (ULS) .......................................... 23
Figure 14: Max. dim. forces (incl. load factor) in bridles for analyses 1-16 ............................................. 24
Figure 15: Max. dim. forces (incl. load factor) in frame components for analyses 1-16 ......................... 24
Figure 16: Max. dim. forces (incl. load factor) in mooring components for analyses 1-16 ..................... 24
Figure 17: Analysis 17 with break in line 3b ............................................................................................ 26
Figure 18: Analysis 18 with cut in line 7................................................................................................... 26
Figure 19: Analysis 19 with cut in line 17................................................................................................. 27
Figure 20: Analysis 20 with cut in frame B1-B2 ....................................................................................... 27
Figure 21: Analysis 21 with break in one of the bridles at ring 102......................................................... 28
Figure 22: Maximum forces in analyses 12, 22 and 23 ............................................................................ 28
Figure 23: Map showing positions of the site and the nearby weather station (San Carlos) .................. 29

3 Table List
Table 1: Summary of components requirements (MBL – Minimum Breaking Load) ................................ 5
Table 2: Wind and wave data in eight directions with 10- and 50-years return periods .......................... 7
Table 3: Current velocities at 5 and 15 meters depth in eight directions ................................................. 7
Table 4: Frame ......................................................................................................................................... 10
Table 5: Frame elements ......................................................................................................................... 10
Table 6: Bridles......................................................................................................................................... 10
Table 7: Data on frame ............................................................................................................................ 11
Table 8: Data on bridles ........................................................................................................................... 11
Table 9: Line type A.................................................................................................................................. 12
Table 10: Mooring lines data ................................................................................................................... 12
Table 11: Mooring component properties – weight in water and stiffness ............................................ 12
Table 12: Positions ................................................................................................................................... 13
Table 13: Buoy number and size in litres ................................................................................................. 13
Table 14: Data floating collar ................................................................................................................... 14

3
Akvasafe AS Tel.: 468 12 632 www.akvasafe.no
Espehaugen 41, Pb. 175 Blomsterdalen Epost: ingve@akvasafe.no Dok-ID: V6.9.05, rev K
5868 Bergen, Norway Org.nr.: NO 997935187 MVA
 Report – Mooring analysis La Manga
FR-12023-0189, rev. 1

Table 15: Load and material factors for mooring components ............................................................... 18
Table 16: Material factors for mooring components .............................................................................. 18
Table 17: Load cases for the ultimate limit state..................................................................................... 21
Table 18: ULS results summary ................................................................................................................ 22
Table 19: Load cases for the accidental limit state .................................................................................. 25
Table 20: Summary results ALS ................................................................................................................ 25
Table 21: ALS results summary ................................................................................................................ 26
Table 22: Load cases for fatigue .............................................................................................................. 29
Table 23: Fatigue calculations .................................................................................................................. 30
Table 24: Chain weight in water and other properties ............................................................................ 31
Table 25: Calculated dimensioning vertical lift at the anchoring points in tonnes ................................. 31
Table 26: Capacity floating collar against submersion (ULS) ................................................................... 32
Table 27: Dimensioning forces in tonnes and associated required MBL for the mooring system .......... 34

4
Akvasafe AS Tel.: 468 12 632 www.akvasafe.no
Espehaugen 41, Pb. 175 Blomsterdalen Epost: ingve@akvasafe.no Dok-ID: V6.9.05, rev K
5868 Bergen, Norway Org.nr.: NO 997935187 MVA
 Report – Mooring analysis La Manga
FR-12023-0189, rev. 1

4 Summary
Table 1: Summary of components requirements (MBL – Minimum Breaking Load)

Site summary
Site La Manga
Position 27°57.911' N; 111°09.766' W
HS(50YR), max 4.00 m from NW
Vc(50YR), max 0.50 m/s towards S and SW
Forces summary
Condition Description Force [tonnes] Component
Maximum dimensioning force 29.1 Frame C1-C2
Intact Maximum dimensioning axial force on floating collar 11.5 Bridle 102
Maximum dimensioning vertical force on floating collar 3.9 Bridle 103
Maximum dimensioning force 26.7 Line 3a
Accident Maximum dimensioning axial force on floating collar 12.5 Bridle 103
Maximum dimensioning vertical force on floating collar 3.3 Bridle 103
Summary of requirements on components
Minimum Bruddlast (MBL)
Min. holding force

Min. holding force

concrete block

Chain and chain

Coupling plates
and steel joints
Rope with knot
anchor/bolt
axial force
Max. dim.

components

attachments
Used chain

Shackles

Bottom
Rope

Line no.

[tonnes] [tonnes] [tonnes] [tonnes] [tonnes] [tonnes] [tonnes] [tonnes] [tonnes] [tonnes]
bridles 11.5 11.5 22.9 34.4 57.3 22.9 57.3 17.2 22.9 -
frame long 29.1 29.1 58.2 87.3 145.5 58.2 145.5 43.7 58.2 -
frame cross 13.7 13.7 27.3 41.0 68.3 27.3 68.3 20.5 27.3 -
1 21.5 21.5 43.0 64.5 107.4 43.0 107.4 32.2 43.0 64.5
2a 21.4 21.4 42.8 64.2 107.0 42.8 107.0 32.1 42.8 64.2
2b 27.2 27.2 54.4 81.6 136.0 54.4 136.0 40.8 54.4 81.6
3a 21.7 21.7 43.3 65.0 108.3 43.3 108.3 32.5 43.3 65.0
3b 28.2 28.2 56.4 84.6 141.0 56.4 141.0 42.3 56.4 84.6
4 23.1 23.1 46.3 69.4 115.6 46.3 115.6 34.7 46.3 69.4
5 13.5 13.5 27.0 40.5 67.6 27.0 67.6 20.3 27.0 40.5
6 20.2 20.2 40.5 60.7 101.2 40.5 101.2 30.4 40.5 60.7
7 20.7 20.7 41.4 62.1 103.6 41.4 103.6 31.1 41.4 62.1
8 19.8 19.8 39.7 59.5 99.2 39.7 99.2 29.8 39.7 59.5
9 13.9 13.9 27.7 41.6 69.3 27.7 69.3 20.8 27.7 41.6
10 7.2 7.2 14.5 21.7 36.2 14.5 36.2 10.9 14.5 21.7
11 10.0 10.0 20.1 30.1 50.2 20.1 50.2 15.1 20.1 30.1
12 9.8 9.8 19.6 29.4 49.0 19.6 49.0 14.7 19.6 29.4
13 9.8 9.8 19.7 29.5 49.2 19.7 49.2 14.8 19.7 29.5
14 10.4 10.4 20.8 31.2 52.0 20.8 52.0 15.6 20.8 31.2
15 17.4 17.4 34.7 52.1 86.9 34.7 86.9 26.1 34.7 52.1
16 16.5 16.5 33.0 49.4 82.4 33.0 82.4 24.7 33.0 49.4
17 17.4 17.4 34.9 52.3 87.2 34.9 87.2 26.2 34.9 52.3
18 13.8 13.8 27.6 41.4 69.0 27.6 69.0 20.7 27.6 41.4
- The capacity of buoys D1 has to be increased.
Observations
- An accredited site survey is not available.
- Replaces revision 0;
- Pipe diameter in floating collars is increased from 400 to 450 mm;
Revision 1 - Wind speed 100 km/h;
- Significant wave height from NW increased to 4.0 metres.

An analysis on moored floating pens commissioned by Erling Haug AS was carried out following
instructions provided in the Norwegian Standard NS 9415 (2009) and NYTEK regulations. An accredited
site survey is not available. Thus, the mooring analysis does not comply with given regulations. The
control level is performed for reliability class 2, which means that an internal quality control is carried
out. The mooring analysis described in this report is done by the inspection body Akvasafe AS with
accreditation number INSP 034.

5
Akvasafe AS Tel.: 468 12 632 www.akvasafe.no
Espehaugen 41, Pb. 175 Blomsterdalen Epost: ingve@akvasafe.no Dok-ID: V6.9.05, rev K
5868 Bergen, Norway Org.nr.: NO 997935187 MVA
 Report – Mooring analysis La Manga
FR-12023-0189, rev. 1

The La Manga fish farming site is located off the coast from the municipality of Guaymas, Sonora,
Mexico. The position of the centre of the farm is 27°57.911' N; 111°09.766' W with HS(50YR) = 4.00 m from
NW and Vc(50YR) = 0.50 m/s towards S and SW.

Table 1 summarizes the minimum breaking loads of the different components in each mooring line. For
further details, please refer to Table 27.

6
Akvasafe AS Tel.: 468 12 632 www.akvasafe.no
Espehaugen 41, Pb. 175 Blomsterdalen Epost: ingve@akvasafe.no Dok-ID: V6.9.05, rev K
5868 Bergen, Norway Org.nr.: NO 997935187 MVA
 Report – Mooring analysis La Manga
FR-12023-0189, rev. 1

5 Site information
The La Manga fish farming site is located off the coast from the municipality of Guaymas, Sonora,
Mexico. The position of the centre of the farm is 27°57.911' N; 111°09.766' W with HS(50YR) = 4.00 m from
NW and Vc(50YR) = 0.50 m/s towards S and SW. The environmental loads are specified by the customer.
No accredited site report is available.

The environmental loads shown in Table 2 and 3 are used in the analyses.

Table 2: Wind and wave data in eight directions with 10- and 50-years return periods

Direction (from) N NE E SE S SW W NW
Direction (°) 0 45 90 135 180 225 270 315
U10yr (m/s) 24.79 24.79 24.79 24.79 24.79 24.79 24.79 24.79
HS10yr (m) 1.43 1.27 1.50 1.03 2.44 2.16 2.23 3.57
TP10yr (s) 3.12 2.85 3.30 2.76 5.08 4.91 4.99 7.58
U50yr (m/s) 27.80 27.80 27.80 27.80 27.80 27.80 27.80 27.80
HS50yr (m) 1.60 1.42 1.68 1.16 2.74 2.42 2.50 4.00
TP50yr (s) 3.50 3.20 3.70 3.10 5.70 5.50 5.60 8.50
Max. ocean waves
Direction (from) N NE E SE S SV V NV
Direction (°) - - - - - - - -
HS10yr (m) - - - - - - - -
TP10yr (s) - - - - - - - -
HS50yr (m) - - - - - - - -
TP50yr (s) - - - - - - - -
Max. combined waves
Direction (from) N NE E SE S SV V NV
Direction (°) - - - - - - - -
HS10yr (m) - - - - - - - -
TP10yr (s) - - - - - - - -
HS50yr (m) - - - - - - - -
TP50yr (s) - - - - - - - -

Table 3: Current velocities at 5 and 15 meters depth in eight directions

5m 15 m
Direction
(towards) Direction 10-yr current 50-yr current Direction 10-yr current 50-yr current
(°) (m/s) (m/s) (°) (m/s) (m/s)
N 0 0.19 0.21 0 0.19 0.21
NE 45 0.29 0.33 45 0.29 0.33
E 90 0.41 0.46 90 0.41 0.46
SE 135 0.43 0.48 135 0.43 0.48
S 180 0.45 0.50 180 0.45 0.50
SW 225 0.45 0.50 225 0.45 0.50
W 270 0.17 0.19 270 0.17 0.19
NW 315 0.22 0.25 315 0.22 0.25

7
Akvasafe AS Tel.: 468 12 632 www.akvasafe.no
Espehaugen 41, Pb. 175 Blomsterdalen Epost: ingve@akvasafe.no Dok-ID: V6.9.05, rev K
5868 Bergen, Norway Org.nr.: NO 997935187 MVA
 Report – Mooring analysis La Manga
FR-12023-0189, rev. 1

Figure 1: Detailed map of the fish farm with mooring

Figure 1 and 2 show the La Manga fish farm and its mooring system.

Figure 2: Location of the fish farm

8
Akvasafe AS Tel.: 468 12 632 www.akvasafe.no
Espehaugen 41, Pb. 175 Blomsterdalen Epost: ingve@akvasafe.no Dok-ID: V6.9.05, rev K
5868 Bergen, Norway Org.nr.: NO 997935187 MVA
 Report – Mooring analysis La Manga
FR-12023-0189, rev. 1

6 Description of main components

6.1 Introduction
The positions of the fish farm and mooring lines were specified by the customer. The facility consists of
a framed mooring with 3 rows of 4 cages each. The floating collars have a circumference of 120 metres.
The frames are 65x65 m in size and lie at a depth of 7 m. Three-piece rope bridles connect the floating
collars to the coupling plates in the frames. The numbering of the lines is based on documentation
provided by the client. The orientation is 122°. Figure 3 shows the layout of the mooring.

Figure 3: Mooring with numbered lines

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Akvasafe AS Tel.: 468 12 632 www.akvasafe.no
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 Report – Mooring analysis La Manga
FR-12023-0189, rev. 1

Figure 4: Positioning of the buoys and cages in the fish farm

6.2 Mooring
6.2.1 Frame and bridles
The frames are 65x65 meter in size and lie at a depth of 7 m. Three-piece rope bridles connect the
floating collars to the coupling plates in the frames. See details in Table 4 through 8.

Table 4: Frame Table 5: Frame elements Table 6: Bridles

Frame Frame elements Bridles

Property Description
a (m) Rope length

Property Description
L1 (m) Frame long. Property Description
L2 (m) Frame transv. Å (m) Opening bridles
H (m) Frame depth a (m) Rope length

10
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 Report – Mooring analysis La Manga
FR-12023-0189, rev. 1

Table 7: Data on frame

Frame
a (m) Rope type
position
A1-A2 65 72 mm 8-strand
A2-A3 65 72 mm 8-strand
A3-A4 65 72 mm 8-strand
A4-A5 65 72 mm 8-strand
B1-B2 65 72 mm 8-strand
B2-B3 65 72 mm 8-strand
B3-B4 65 72 mm 8-strand
B4-B5 65 72 mm 8-strand
C1-C2 65 72 mm 8-strand
C2-C3 65 72 mm 8-strand
C3-C4 65 72 mm 8-strand
C4-C5 65 72 mm 8-strand
D1-D2 65 72 mm 8-strand
D2-D3 65 72 mm 8-strand
D3-D4 65 72 mm 8-strand
D4-D5 65 72 mm 8-strand
A1-B1 65 72 mm 8-strand
A2-B2 65 72 mm 8-strand
A3-B3 65 72 mm 8-strand
A4-B4 65 72 mm 8-strand
A5-B5 65 72 mm 8-strand
B1-C1 65 72 mm 8-strand
B2-C2 65 72 mm 8-strand
B3-C3 65 72 mm 8-strand
B4-C4 65 72 mm 8-strand
B5-C5 65 72 mm 8-strand
C1-D1 65 72 mm 8-strand
C2-D2 65 72 mm 8-strand
C3-D3 65 72 mm 8-strand
C4-D4 65 72 mm 8-strand
C5-D5 65 72 mm 8-strand

Table 8: Data on bridles

Å
Cage a (m) Rope type
(m)
1 14.6 27.1/29.4 56 mm 3-strand
2 14.6 27.1/29.4 56 mm 3-strand
3 14.6 27.1/29.4 56 mm 3-strand
4 14.6 27.1/29.4 56 mm 3-strand
5 14.6 27.1/29.4 56 mm 3-strand
6 14.6 27.1/29.4 56 mm 3-strand
7 14.6 27.1/29.4 56 mm 3-strand
8 14.6 27.1/29.4 56 mm 3-strand

11
Akvasafe AS Tel.: 468 12 632 www.akvasafe.no
Espehaugen 41, Pb. 175 Blomsterdalen Epost: ingve@akvasafe.no Dok-ID: V6.9.05, rev K
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 Report – Mooring analysis La Manga
FR-12023-0189, rev. 1

6.2.2 Anchor lines

The components in the mooring system are described in Table 9, 10 and 11.

Table 9: Line type A

Line type A

Property Description
a (m) Rope length
b (m) Bottom chain length
Anchoring Anchor

Table 10: Mooring lines data

Line Line a b Anchoring Bottom chain

Rope type
no. type [m] [m] type type
1 A 160 27,5 Megahold 35 72 mm 8-strand 36 mm stud
1 A 160 27,5 Megahold 35 72 mm 8-strand 36 mm stud
2a A 160 27,5 Megahold 35 72 mm 8-strand 36 mm stud
2b A 160 27,5 Megahold 35 72 mm 8-strand 36 mm stud
3a A 160 27,5 Megahold 35 72 mm 8-strand 30 mm studless
3b A 160 27,5 Megahold 35 72 mm 8-strand 30 mm studless
4 A 160 27,5 Megahold 35 72 mm 8-strand 30 mm studless
5 A 160 27,5 Megahold 35 72 mm 8-strand 30 mm studless
6 A 160 27,5 Megahold 35 72 mm 8-strand 30 mm studless
7 A 160 27,5 Megahold 35 72 mm 8-strand 30 mm studless
8 A 160 27,5 Megahold 35 72 mm 8-strand 30 mm studless
9 A 160 27,5 Megahold 35 72 mm 8-strand 30 mm studless
10 A 160 27,5 Megahold 35 72 mm 8-strand 30 mm studless
11 A 160 27,5 Megahold 35 72 mm 8-strand 30 mm studless
12 A 160 27,5 Megahold 35 72 mm 8-strand 30 mm studless
13 A 160 27,5 Megahold 35 72 mm 8-strand 30 mm studless
14 A 160 27,5 Megahold 35 72 mm 8-strand 30 mm studless
15 A 160 27,5 Megahold 35 72 mm 8-strand 30 mm studless
16 A 160 27,5 Megahold 35 72 mm 8-strand 30 mm studless
17 A 160 27,5 Megahold 35 72 mm 8-strand 30 mm studless
18 A 160 27,5 Megahold 35 72 mm 8-strand 30 mm studless

Table 10 shows an overview of the mooring line components used in the model. The component
properties are shown in Table 11. When dimensioning the different mooring components, please refer
to Table 27. The analyses results reproduce the behaviour of the structure with the components
described above. Any variation in the dimensions of these components may affect the results. Table 12
shows the positions of the moorings. The START points indicate the positions in the frame whilst the
END points indicate the position of the anchoring point.

Table 11: Mooring component properties – weight in water and stiffness

weight EA
Component
[N/m] [N]

56 mm 3-strand rope 1.00 4.60E+06

72 mm 8-strand rope 1.00 6.92E+06
30 mm studless chain 215.32 2.30E+08
36 mm stud chain 258.51 2.76E+08

12
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 Report – Mooring analysis La Manga
FR-12023-0189, rev. 1

Table 12: Positions

START END Depth

Direction
anchor point
Point/Line Latitude (N) Longitude (W) Latitude (N) Longitude (W) (°)
(m)
Fisheries dir. - - - - - -
Centre point 27°57.911' 111°09.766' - - - -
NW 27°57.994' 111°09.800' - - - -
NE 27°57.918' 111°09.666' - - - -
SE 27°57.829' 111°09.730' - - - -
SW 27°57.905' 111°09.864' - - - -
1 27°57.905' 111°09.864' 27°57.957' 111°09.957' 55 302
2a 27°57.935' 111°09.843' 27°57.958' 111°09.937' 55 300
2b 27°57.935' 111°09.843' 27°57.990' 111°09.934' 55 304
3a 27°57.964' 111°09.821' 27°58.013' 111°09.916' 55 300
3b 27°57.964' 111°09.821' 27°58.019' 111°09.912' 55 304
4 27°57.994' 111°09.800' 27°58.046' 111°09.893' 55 302
5 27°57.994' 111°09.800' 27°58.076' 111°09.741' 55 32
6 27°57.975' 111°09.767' 27°58.057' 111°09.707' 55 32
7 27°57.956' 111°09.733' 27°58.038' 111°09.674' 55 32
8 27°57.937' 111°09.699' 27°58.019' 111°09.640' 55 32
9 27°57.918' 111°09.666' 27°58.000' 111°09.606' 55 32
10 27°57.918' 111°09.666' 27°57.866' 111°09.573' 55 122
11 27°57.890' 111°09.686' 27°57.837' 111°09.594' 55 122
12 27°57.860' 111°09.707' 27°57.808' 111°09.614' 55 122
13 27°57.829' 111°09.730' 27°57.776' 111°09.637' 55 122
14 27°57.829' 111°09.730' 27°57.747' 111°09.790' 55 212
15 27°57.848' 111°09.764' 27°57.767' 111°09.823' 55 212
16 27°57.867' 111°09.797' 27°57.786' 111°09.856' 55 212
17 27°57.886' 111°09.830' 27°57.807' 111°09.889' 55 212
18 27°57.905' 111°09.864' 27°57.823' 111°09.924' 55 212

6.2.3 Buoys
Figure 4 shows the positioning of the buoys in the installation, whilst Table 13 indicates the buoy
numbers and sizes in litres.

Table 13: Buoy number and size in litres

Buoy no. Size [l] Buoy no. Size [l]

A1 4100 C1 2100
A2 2100 C2 680
A3 2100 C3 680
A4 2100 C4 680
A5 2100 C5 2100
B1 2100 D1 4200
B2 680 D2 2100
B3 680 D3 2100
B4 680 D4 2100
B5 2100 D5 2100

The Tables in the results section should be consulted for the correct dimensioning of the mooring lines.

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6.3 Floating collar

The customer has stated the use of Polarcirkel plastic floating collars with double Ø450 mm tubes. The
circumference of the collars is 120 m.

Table 14: Data floating collar

Model: 120m – Ø450 Polarcirkel

Max. allowed
Circumference Net buoyancy
Dim. pipes [mm] SDR pipe bridle force
[m] [tonnes]
[tonnes]
120 2 x Ø450 13,6 13,6 29,8

6.4 Nets

Figure 5: Specification from customer

The fish farm has cylindrical nets using EcoNet mesh. The big mesh has been used with calculated 15%
solidity and 22.4% including 50% fowling. The bottom ring is calculated with 35 kg/m and the tip
weight has 500 kg. The values refer to weight in water. Figure 9 in chapter 8 shows the net model.

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7 Analysis Tools
The analyses are carried out with AquaSim, a calculation tool developed by Aquastructures AS. AquaSim
is based on time simulation. The program takes into consideration the effects from non-linear responses
of the different components, their interaction and effect in the overall system. The use of this program
allows to mimic the real physics of the system. In the present case, the following assumptions have been
made:

- Dynamic analysis
- Linear waves
- Mooring lines use the Morison equation with the crossflow principle
- Nets use the Morison equation according to the membrane theory that provides drag and lift
components
- The model takes into account if the body is below or above water when vertical forces are
calculated. This means that the buoyancy forces on a floating element are set to the maximum
volume of the element and the minimal buoyancy force is zero
- Froude Kriloff forces are calculated for the horizontal plane of the cross sections
- Current contribution is represented with interpolated values throughout the entire water
column
- A shadowing effect on succeeding nets is considered
The mooring system is modelled using nodes and elements. Loads calculated on floating structures and
mooring lines are produced by current, wind and waves.

Each simulation has five initial steps, where current builds up from 0 m/s up to its maximum value.
Subsequently, the wave profile for 𝐻𝑠 builds up in one period, and a fully developed wave interacts with
the system in a second period. Each wave is divided into 20 steps and each step is calculated with up to
1200 iterations. At least three analyses with different orientations are visually controlled in order to
check that the system is stable at the initial steps and that reasonable values are being calculated. The
5 m and 15 m depth currents are used in each run. An example of a current profile with two different
current speeds is illustrated in Figure 6.

Figure 6: Example of a flow profile with two different flow rates

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8 Model
The model is generated in AquaSim, see Figure 7. It consists of 4504 nodes and 5031 elements. The
floating collar is modelled with beam elements, the net with membrane and truss elements, and the
mooring lines with truss elements.

Figure 7: View of the model

In order to model the seabed at different depths, “displaced” springs are used in some bottom chain
nodes. Figure 6shows the simulated behaviour of the bottom chain with bottom contact (a, b and c) and
“hanging”, without bottom contact (d, e and f). In every node a load of two Newtons is applied (in the
positive z-direction) together with a “displaced” spring with a stiffness of 1000 N/m (in the positive z-
direction).

(a) (b) (c)

(d) (e) (f)

Figure 8: Behaviour of the bottom chain with (above) and without (below) contact with the seabed

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Figure 9: Net model

The net, Figure 9, is modelled with membrane and truss elements. A concentrated load is applied to
the tip of the net.

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9 Load cases

9.1 Introduction
Three sets of analyses must be executed according to NS9415:2009:

a. Ultimate limit state (ULS);

b. Accidental limit state (ALS);
c. Fatigue limit state (FLS).

Results must staisfy the following condition:

𝑀𝐵𝐿
𝐹 ∙ 𝛾𝑓 ≤ (2)
𝛾𝑚
Where 𝐹 is the force to which the mooring component is subjected to (obtained from the simulations),
𝑀𝐵𝐿 is the minimum breaking load of the component, while 𝛾𝑓 and 𝛾𝑚 are the load and material
factors, see Table 15 and Table 16 (NS9415:2009).

Table 15: Load and material factors for mooring components

Analysis 𝛾𝑓 𝛾𝑚
ULS 1.15 see Table 16
ALS 1 𝛾𝑚 ⁄1.5

Table 16: Material factors for mooring components

Mooring component 𝛾𝑚
Synthetic ropes 3.0
Synthetic ropes with knots 5.0
Chains and chain components 2.0
Used chains 5.0
Coupling plates and other steel coupling elements (first yield) 1.5
Shackles 2.0
Rock bolts and other anchoring elements 3.0

The dimensioning force is defined as:

𝐹𝑑𝑖𝑚 = 𝐹 ∙ 𝛾𝑓 (3)
And,

𝐹𝑚𝑎𝑥 = 𝐹 ∙ 𝛾𝑓 ∙ 𝛾𝑚 = 𝐹𝑑𝑖𝑚 ∙ 𝛾𝑚 (4)

The following inequality must be satisfied:

𝐹𝑚𝑎𝑥 ≤ 𝑀𝐵𝐿 (5)

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9.2 Serviceability limit state

The mooring system is considered exempt from any impaired functionality or reduced resistance under
normal conditions. The regular operating conditions considered are:

- Net replacement
- Net cleaning
- Delousing
- Maintenance of net weights
- Removal of dead fish
Other operating conditions are not considered.

9.3 Ultimate limit state (ULS)

Calculations are performed in order to demonstrate that the moorings withstand the design forces
specified in the site survey.

9.4 Accidental limit state (ALS)

Accidental limit states should be controlled for the following events; progressive break of lines, free
drifitng, capsizing or sinking in special conditions related to collisions with boats, equipment or
accessories.

Two aspects should be controlled:

i. Break of a mooring line. The strength and drifting of the mooring system which may
cause collisions and/or the progressive break of other components when:
a. the most loaded line breaks;
b. a line that is critical in maintaining the integrity of a floating cage breaks;
c. a break is produced in a coupling point (for example in a coupling plate);
d. a line that is critical in the positioning of one or more cages breaks, and the
subsequent drift may result in a collision. This is irrelevant for the mooring of
aquaculture installations.
ii. Spring tide. The water level should be raised 1 meter above the upper tidal level.
In the accidental limit state, the material factors are divided by 1.5. The effect of wind, waves and current
shall be incorporated in the load combination.

9.5 Fatigue limit state (FLS)

Fatigue is dependent upon load variations in time. Consideration should be given to loads that vary with
wave frequency. Chains, made of steel, should be subjected to fatigue analysis.

Calculations are done according to the S-N curve theory, with the number of cycles to fracture 𝑛(𝑠)

𝑛(𝑠) = 𝑎 ∙ 𝑠 −𝑚 (1)

Studless chain: 𝑎 = 6 ∙ 1010 , 𝑚 = 3

Stud link chain: 𝑎 = 1.2 ∙ 1011 , 𝑚 = 3

According to NS 9415:2009 section 11.6.2, the analysis should be base don the 20 year design life. Values
for studless chains are considered.

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The values for the 50-year waves are obtained from the site report. The prevailing wind direction is
assumed to be the direction from which all waves come. This is a conservative assumption.

The main direction is divided into ten blocks with percentile wave distribution. The duration of a sea
state is set to three hours and the Weibull factor ℎ associated with the distribution of 𝐻𝑠 is set to a value
of one.

The distribution is based on DNV-RP-C203 (2010).

In addition, wind and current data is necessary. The 10-year wind and current values are used, the latter
being multiplied by a factor of 0.5. This is, again, a conservative assumption as average values for current
and wind are far below the values for the 10 year return period.

From the analyses, the nominal stress range for the chain components is obtained. Based on the nominal
stress range of the 10 blocks, the 20 year accumulated damage for each component is found.

9.6 Load factors and load combinations used in the analyses

For analyses of the ultimate limit state, eight different directions with two load combinations each are
considered. In the case of fatigue, a main direction with ten blocks is used. The accidental load state
analyses are based on risk assessment; generally, the most highly loaded lines as considered, as well as
components which may lead to the escape of fish.

According to NS9415:2009 the load factor in the ULS is equal to 1.15, and 1.0 in the case of the ALS.

𝛾𝑓−𝑈𝐿𝑆 = 1.15, 𝛾𝑓−𝐴𝐿𝑆 = 1.0

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10 Results
The following results are based on the analyses defined in Table 17, 19 and 22.

10.1 Static equilibrium – pretension

Figure 10 shows pretension in the mooring lines without waves and current. The forces are calculated
including a loading factor of 1.15. These results are informative and not intended as a requirement.

3000
2500
Kraft [kg]

2000
1500
1000
500
0
bridles

11

16
1

4
5
6
7
8
9
10

12
13
14
15

17
18
2a

3a
frame side

2b

3b
frame long

Figure 10: Pretension with static equilibrium

10.2 Ultimate limit state (ULS)

Table 17 shows an overview of the conditions, which define the ultimate limit state analyses. Figure
14, 15 and 16 show maximum forces in detail for bridles, frame elements and mooring lines.

Table 17: Load cases for the ultimate limit state

Direction Current [m/s] Wind

Analysis towards Hs [m] Tp [s] Description
(nautical) 5m 15 m [m/s]
1 N 2.44 5.08 0.21 0.21 24.79
2 NE 2.16 4.91 0.33 0.33 24.79
3 E 2.23 4.99 0.46 0.46 24.79
4 SE 3.57 7.58 0.48 0.48 24.79 Combination 1:
50-yr current
5 S 1.43 3.12 0.50 0.50 24.79 10-yr wave and wind
6 SW 1.27 2.85 0.50 0.50 24.79
7 W 1.50 3.30 0.19 0.19 24.79
8 NW 1.03 2.76 0.25 0.25 24.79
9 N 2.74 5.70 0.19 0.19 27.80
10 NE 2.42 5.50 0.29 0.29 27.80
11 E 2.50 5.60 0.41 0.41 27.80
12 SE 4.00 8.50 0.43 0.43 27.80 Combination 1:
10-yr current
13 S 1.60 3.50 0.45 0.45 27.80 50-yr wave and wind
14 SW 1.42 3.20 0.45 0.45 27.80
15 W 1.68 3.70 0.17 0.17 27.80
16 NW 1.16 3.10 0.22 0.22 27.80

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Table 18: ULS results summary

Force
Component Analysis Figure Comment
[tonnes]
Frame C1-C2 29.1 12 11 Highest loads found in the mooring system
Line 3b 28.2 12 11 Highest loads found in the mooring lines
Bridle 102 11.5 12 13 Highest loads found in the bridles
Line 7 20.7 6 12 Highest loads in the lines heading towards the NE

Figure 11: Analysis 12 of 16 produces the highest load in lines 3b, bridle 102 and in frame C1-C2 (ULS)

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Figure 12: Analysis 6 of 16 produces the highest loads in the North-eastern lines (ULS)

Figure 13: Analysis 12 of 16 produces the highest loads in bridle 102 (ULS)

Figure 16 shows an overview of the maximum forces found the mooring system. See Table 27 for details
on forces and minimum breaking loads (MBL).

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Bridles
15,0
11,5
Force [tonnes]

10,1 10,5
9,5 9,6
10,0 7,8 7,8 7,7 7,8 8,4
6,5 6,3

5,0

0,0
bridle bridle bridle bridle bridle bridle bridle bridle bridle bridle bridle bridle
101 201 301 401 102 202 302 402 103 203 303 403

Figure 14: Max. dim. forces (incl. load factor) in bridles for analyses 1-16

Frame
40,0
Force [tonnes]

27,5 29,1
30,0
19,8 19,1
16,9
20,0 15,5 13,713,4 11,8
9,9 10,7 11,7 11,9
9,8 10,3 12,2 10,4
7,1 6,9 7,3 6,6 7,0 7,1 8,2 7,5 8,1
10,0 5,6 4,7 5,1 6,6 4,6

0,0
B1-B2
B2-B3
B3-B4
B4-B5
A1-A2
A2-A3
A3-A4
A4-A5

C1-C2
C2-C3
C3-C4
C4-C5

B1-C1
B2-C2
B3-C3
B4-C4
B5-C5
C1-D1
C2-D2
C3-D3
C4-D4
C5-D5
D1-D2
D2-D3
D3-D4
D4-D5
A1-B1
A2-B2
A3-B3
A4-B4
A5-B5

Figure 15: Max. dim. forces (incl. load factor) in frame components for analyses 1-16

Mooring lines
28,2
30,0 27,2
23,1
25,0 21,5 21,4 21,7
Force [tonnes]

20,2 20,7 19,8

20,0 17,4 16,5 17,4
13,5 13,9 13,8
15,0 10,4
10,0 9,8 9,8
10,0 7,2

5,0
0,0
1 2a 2b 3a 3b 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

Figure 16: Max. dim. forces (incl. load factor) in mooring components for analyses 1-16

10.2.1 Discussion
The highest forces are found in the frame component between buoys C1 and C2. The value is 29.1
tonnes. Next, we found a force of 28.2 tonnes in line 3b (towards NE). The bridles vary in force from
6.3 to a maximum value of 11.5 tonnes (ring 102).

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10.3 Accidental limit state (ALS)

10.3.1 Introduction
7 accidental conditions were simulated, see Table 19.

Breaks are considered in lines with the highest loads and/or that will have the worst impact on the
mooring.

Table 19: Load cases for the accidental limit state

Ref.
Analysis Kommentar
analysis1
17 12 Rupture in line 3b. Highest load in lines.
18 6 Rupture in line 7. Highest load in lines towards NE.
19 2 Rupture in line 17. Highest load in lines towards SW.
20 12 Rupture in frame C1-C2. Highest load in frame.
21 12 Rupture in bridle 102. Highest load in bridles.
22 12 High tide 3m.
23 12 Puncture ring 102.

Table 20: Summary results ALS

Analysis Figure Kommentar

17 17 Force in line 3a increase to 26.7 tonnes.
18 18 Forces in line 6 and 8 increase to 23.8 and 23.3 tonnes.
19 19 Forces in line 16 and 18 increase to 18.4 and 14.6 tonnes.
20 20 Force in bridle 101 increases to 12.4 tonnes.
21,22,23 21, 22 No important changes in the forces were found.

1
Reference to environmental conditions defined in Table 17.

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Table 21: ALS results summary

Figure 17: Analysis 17 with break in line 3b

Figure 18: Analysis 18 with cut in line 7

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Figure 19: Analysis 19 with cut in line 17

Figure 20: Analysis 20 with cut in frame C1-C2

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Figure 21: Analysis 21 with break in one of the bridles at ring 102

30,0
Force [tonnes]

25,0
20,0
15,0
10,0
5,0
0,0

Analysis 12 Analysis 22 Analysis 23

Figure 22: Maximum forces in analyses 12, 22 and 23

10.3.2 Spring tide

A sea level rise of 3 meters as simulated in analysis 22 has no greater impact on the mooring due to the
elasticity of the connections between the frame and the anchoring points, see Figure 22. The
requirements to minimum breaking load (MBL) in the components stay below the maximum values for
this mooring analysis.

10.3.3 Punctures
The loss of floating elements is considered to influence critically the forces in the mooring system. In
case the tubes are filled with floating elements the effect on the mooring system won’t have a critical
effect. In analysis 23, cage 102 has a reduced buoyancy as one ring was simulated punctured. There is
no increase in required MBL in any mooring components, see Figure 22.

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10.4 Fatigue limit state (FLS)

Based on wind statistics (Wind & weather statistics, 2017) from San Carlos/Guaymas about 7 nautical
miles to the East (90°) from the planned site, the wind and current coming from the South are considered
to produce the highest fatigue in the mooring. See Table 22 for a summary of the analyses for fatigue.
No rope element exceeds a stress of 170 MPa, thus the fatigue resistance of these elements is deemed
satisfactory. Table 23 lists the elements which have been evaluated.

Figure 23: Map showing positions of the site and the nearby weather station (San Carlos)

Table 22: Load cases for fatigue

Heading to Current [m/s] Wind

Analysis Hs [m] Tp [s] Comments
(compass) 5m 15 m [m/s]
24 N 0.11 1.26 0.09 0.09 24.79
25 N 0.22 1.78 0.09 0.09 24.79 Fatigue
26 N 0.34 2.18 0.09 0.09 24.79 with 10 blocks
27 N 0.45 2.51 0.09 0.09 24.79 in one direction.
N 0.56 2.81 0.09 0.09 24.79 50-year return period
28
for waves and 10-year
29 N 0.67 3.08 0.09 0.09 24.79 return period for current
30 N 0.78 3.33 0.09 0.09 24.79 and wind.
31 N 0.90 3.56 0.09 0.09 24.79 Current is multiplied by
32 N 1.01 3.77 0.09 0.09 24.79 a factor of 0.5.
33 N 1.12 3.98 0.09 0.09 24.79

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Table 23: Fatigue calculations

Detail Description Max. stress range [MPa]

components
Examined

Detail 1 Bottom chain line 13 16.22

Detail 2 Bottom chain line 8 14.32
Detail 3 Bottom chain line 6 12.4
Detail 4 Bottom chain line 7 14.79
Block no. Detail 1 Detail 2 Detail 3 Detail 4
Block 1 1.262 3.291 3.474 2.791
Stress ranges [MPa]

Block 2 2.040 4.164 4.364 4.300

Block 3 4.756 6.247 5.756 5.726
Block 4 4.700 8.437 7.141 7.055
Block 5 16.220 5.851 6.951 6.765
Block 6 8.152 7.259 7.446 7.442
Block 7 12.070 14.320 12.400 14.790
Block 8 11.660 5.515 6.194 8.158
Block 9 10.640 7.852 6.894 5.783
Block 10 12.380 8.707 4.553 8.219
Block no. Detail 1 Detail 2 Detail 3 Detail 4
Partial and accumulated (20 years)

Block 1 0.020329 0.360512 0.424058 0.219895

Block 2 0.018487 0.157224 0.180984 0.173137
damage per block

Block 3 0.058241 0.131983 0.103244 0.101639

Block 4 0.014822 0.085736 0.051985 0.050129
Block 5 0.165906 0.007788 0.013057 0.012037
Block 6 0.005854 0.004133 0.004461 0.004454
Block 7 0.005357 0.008945 0.005808 0.009856
Block 8 0.001375 0.000146 0.000206 0.000471
Block 9 0.000300 0.000121 0.000082 0.000048
Block 10 0.000150 0.000052 0.000007 0.000044
Total 0.290822 0.756640 0.783893 0.571710
Lifespan yr >20 years >20 years >20 years >20 years

A total accumulated damage of 1 or less means that the component has a life expectancy of 20 years or
more. Table 23 shows that the bottom chains have a lifespan of more than 20 years.

10.5 Anchor points

The values of the vertical component of the axial force in the bottom chains are extracted, and the
weight of the chains in water (and of any other element attached to the bottom) and of any loads is
subtracted. This way, the residual uplift force at the anchoring points is calculated, see Table 25.

When the residual uplift is greater than the bottom weight / anchor weight, there is a risk of loosening
of the anchor point. In such cases, it must be verified and documented that the bottom weight / anchor
can withstand vertical forces equal to or greater than the values listed in Table 25.

The bottom chain is assumed to have the properties listed in Table 24.

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Table 24: Chain weight in water and other properties

weight in density density volume weight in

chain air/m steel water steel/m water/m
[kg/m] [kg/m3] [kg/m3] [m3] [kg/m]
30 mm 19.5 7850 1025 0.0024 17.0
36 mm 30.4 7850 1025 0.0039 26.4

Table 25: Calculated dimensioning vertical lift at the anchoring points in tonnes

Weight Residual Required

Line Uplift chain Load Weight chain
anchor uplift MBL
no. [tonnes] [tonnes] [tonnes]
[tonnes] [tonnes] [tonnes]
1 5.3 0 0.72 0.65 3.90 64.4
2a 5.3 0 0.72 0.65 3.89 64.0
2b 6.7 0 0.72 0.65 5.35 81.3
3a 5.4 0 0.72 0.65 4.03 64.9
3b 7.1 0 0.72 0.65 5.71 84.5
4 5.6 0 0.72 0.65 4.26 69.2
5 3.3 0 0.47 0.65 2.18 40.5
6 5.0 0 0.47 0.65 3.84 60.7
7 5.1 0 0.47 0.65 3.97 62.1
8 4.9 0 0.47 0.65 3.77 59.5
9 3.3 0 0.47 0.65 2.23 41.5
10 1.7 0 0.47 0.65 0.61 21.7
11 2.4 0 0.47 0.65 1.32 29.9
12 2.4 0 0.47 0.65 1.26 29.2
13 2.4 0 0.47 0.65 1.25 29.5
14 2.5 0 0.47 0.65 1.43 31.2
15 4.3 0 0.47 0.65 3.18 51.8
16 4.0 0 0.47 0.65 2.92 49.1
17 4.4 0 0.47 0.65 3.29 52.3
18 3.3 0 0.47 0.65 2.15 41.3

𝑅𝑒𝑠𝑖𝑑𝑢𝑎𝑙 𝑢𝑝𝑙𝑖𝑓𝑡 = 𝑈𝑝𝑙𝑖𝑓𝑡 𝑐ℎ𝑎𝑖𝑛 − 𝐿𝑜𝑎𝑑 − 𝐶ℎ𝑎𝑖𝑛 𝑤𝑒𝑖𝑔ℎ𝑡 − 𝐴𝑛𝑐ℎ𝑜𝑟 𝑤𝑒𝑖𝑔ℎ𝑡

The required MBL for the anchoring points is specified. Please note that the specified weight of the
components is the weight in water. As can be seen from Table 25, all the anchor points experience
residual uplift. The installation company shall determine the vertical uplift that each anchor can
withstand. A residual uplift greater than 0 does not mean necessarily that the anchor point will detach,
but it is important to check that the anchor is firmly attached to the seabed.

The calculations were done considering an anchor weight of 750 kg (dry condition).

10.6 Forces acting on the floating collars

The highest axial force to which the floating collar is subjected in the ULS is 11.5 tonnes between cage
102 and buoy C1 (3.9 tonnes vertical component at ring 103). The highest axial force to which the floating
collar is subjected in the ALS is 12.5 tonnes at cage 103 (3.3 tonnes vertical component). A Polarcirkel
floating collar with 2xØ450 mm tubes and a 120 m circumference can withstand 13.6 tonnes while using
three-rope bridles for ULS-condition. For the ALS-condition, a value of 22.1 tonnes is used based on

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adapted safety factors. As we see from the results, the floating collar can withstand the forces exerted
by the mooring.

10.7 Buoy forces

The forces presented in Table 26 represent the maximum values found in the ULS analyses in kg. The
specified buoy sizes in litres from Table 13 were used in the model. See Figure 4 for the positions of
the buoys in the frame.

Table 26: Capacity floating collar against submersion (ULS)

Buoyancy
Max. vert. force contribution Difference
Ring-Buoy
[kg] from collar(s) [kg]
[kg]
101-A1 4353 6250 1897
101-A2 4487 6250 1763
101-B1 4651 6250 1599
101-B2 1086 6250 5164
201-A2 2728 6250 3522
201-A3 1706 6250 4544
201-B2 1904 6250 4346
201-B3 536 6250 5714
301-A3 2758 6250 3492
301-A4 2031 6250 4219
301-B3 1937 6250 4313
301-B4 637 6250 5613
401-A4 2519 6250 3731
401-A5 3005 6250 3245
401-B4 1777 6250 4473
401-B5 1414 6250 4836
102-B1 4632 6250 1618
102-B2 801 6250 5449
102-C1 5315 6250 935
102-C2 1125 6250 5125
202-B2 1909 6250 4341
202-B3 705 6250 5545
202-C2 2052 6250 4198
202-C3 604 6250 5646
302-B3 927 6250 5323
302-B4 729 6250 5521
302-C3 1154 6250 5096
302-C4 648 6250 5602
402-B4 1619 6250 4631
402-B5 1869 6250 4381
402-C4 1008 6250 5242
402-C5 1654 6250 4596
103-C1 5346 6250 904
103-C2 666 6250 5584
103-D1 7139 6250 -889
103-D2 2673 6250 3577
203-C2 1797 6250 4453
203-C3 535 6250 5715

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203-D2 4280 6250 1970

203-D3 2278 6250 3972
303-C3 900 6250 5350
303-C4 700 6250 5550
303-D3 3084 6250 3166
303-D4 2371 6250 3879
403-C4 2845 6250 3405
403-C5 1827 6250 4423
403-D4 3497 6250 2753
403-D5 3154 6250 3096

Some of the buoys will experience immersion. The equipment supplier should be consulted to determine
the correct buoy sizes. Immersion of a buoy does not necessarily mean that there is the danger of fish
escape as the floating collar(s) provide with complementary buoyancy.

The value in the Difference column in Table 26 must always be positive. If the sum of these two values
(“Difference”) gives a negative value there is danger of fish escape and the value will be marked in red.

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10.8 Mooring requirements

Table 27: Dimensioning forces in tonnes and associated required MBL for the mooring system

Chain and chain

Coupling plates
and steel joints
Rope with knot

components

attachments
Used chain
axial force
Max. dim.

Shackles

Bottom
Rope
[tonnes] [tonnes] [tonnes] [tonnes] [tonnes] [tonnes] [tonnes] [tonnes]
Bridle ring 101 10.1 30.2 50.3 20.1 50.3 15.1 20.1 -
Bridle ring 201 7.8 23.4 38.9 15.6 38.9 11.7 15.6 -
Bridle ring 301 7.8 23.5 39.2 15.7 39.2 11.8 15.7 -
Bridle ring 401 6.5 19.6 32.7 13.1 32.7 9.8 13.1 -
Bridle ring 102 11.5 34.4 57.3 22.9 57.3 17.2 22.9 -
Bridles

Bridle ring 202 9.5 28.6 47.7 19.1 47.7 14.3 19.1 -
Bridle ring 302 7.7 23.1 38.5 15.4 38.5 11.5 15.4 -
Bridle ring 402 6.3 18.8 31.3 12.5 31.3 9.4 12.5 -
Bridle ring 103 10.5 31.6 52.7 21.1 52.7 15.8 21.1 -
Bridle ring 203 9.6 28.8 48.0 19.2 48.0 14.4 19.2 -
Bridle ring 303 7.8 23.4 39.0 15.6 39.0 11.7 15.6 -
Bridle ring 403 8.4 25.2 41.9 16.8 41.9 12.6 16.8 -
A1-A2 15.5 46.5 77.4 31.0 77.4 23.2 31.0 -
A2-A3 9.9 29.6 49.4 19.8 49.4 14.8 19.8 -
A3-A4 5.6 16.9 28.1 11.3 28.1 8.4 11.3 -
A4-A5 4.7 14.2 23.7 9.5 23.7 7.1 9.5 -
B1-B2 27.5 82.5 137.6 55.0 137.6 41.3 55.0 -
B2-B3 19.8 59.3 98.9 39.6 98.9 29.7 39.6 -
53.5 16.1 21.4 -
Frame long

B3-B4 10.7 32.1 53.5 21.4

B4-B5 7.1 21.4 35.6 14.3 35.6 10.7 14.3 -
C1-C2 29.1 87.3 145.5 58.2 145.5 43.7 58.2 -
C2-C3 19.1 57.3 95.5 38.2 95.5 28.6 38.2 -
C3-C4 11.7 35.1 58.4 23.4 58.4 17.5 23.4 -
C4-C5 6.9 20.7 34.5 13.8 34.5 10.3 13.8 -
D1-D2 16.9 50.6 84.4 33.8 84.4 25.3 33.8 -
D2-D3 11.9 35.7 59.6 23.8 59.6 17.9 23.8 -
D3-D4 9.8 29.5 49.2 19.7 49.2 14.8 19.7 -
D4-D5 5.1 15.4 25.7 10.3 25.7 7.7 10.3 -
Chain and chain

Coupling plates
and steel joints
Rope with knot

components

attachments
Used chain
axial force
Max. dim.

Shackles

Bottom
Rope

Component

[tonnes] [tonnes] [tonnes] [tonnes] [tonnes] [tonnes] [tonnes] [tonnes]

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Chain and chain

Coupling plates
and steel joints
Rope with knot

components

attachments
Used chain
axial force
Max. dim.

Shackles

Bottom
Rope
Component

[tonnes] [tonnes] [tonnes] [tonnes] [tonnes] [tonnes] [tonnes] [tonnes]

A1-B1 6.6 19.8 33.1 13.2 33.1 9.9 13.2 -
A2-B2 10.3 31.0 51.6 20.7 51.6 15.5 20.7 -
A3-B3 12.2 36.7 61.2 24.5 61.2 18.4 24.5 -
A4-B4 10.4 31.3 52.2 20.9 52.2 15.7 20.9 -
A5-B5 7.3 22.0 36.7 14.7 36.7 11.0 14.7 -
B1-C1 6.6 19.8 33.0 13.2 33.0 9.9 13.2 -
Frame cross

B2-C2 7.0 20.9 34.8 13.9 34.8 10.4 13.9 -

B3-C3 7.1 21.4 35.7 14.3 35.7 10.7 14.3 -
B4-C4 8.2 24.6 41.0 16.4 41.0 12.3 16.4 -
B5-C5 4.6 13.8 23.1 9.2 23.1 6.9 9.2 -
C1-D1 7.5 22.6 37.7 15.1 37.7 11.3 15.1 -
C2-D2 13.7 41.0 68.3 27.3 68.3 20.5 27.3 -
C3-D3 13.4 40.1 66.8 26.7 66.8 20.0 26.7 -
C4-D4 11.8 35.5 59.2 23.7 59.2 17.8 23.7 -
C5-D5 8.1 24.2 40.3 16.1 40.3 12.1 16.1 -
Line 1 21.5 64.5 107.4 43.0 107.4 32.2 43.0 64.5
Line 2a 21.4 64.2 107.0 42.8 107.0 32.1 42.8 64.2
Line 2b 27.2 81.6 136.0 54.4 136.0 40.8 54.4 81.6
Line 3a 21.7 65.0 108.3 43.3 108.3 32.5 43.3 65.0
Line 3b 28.2 84.6 141.0 56.4 141.0 42.3 56.4 84.6
Line 4 23.1 69.4 115.6 46.3 115.6 34.7 46.3 69.4
Line 5 13.5 40.5 67.6 27.0 67.6 20.3 27.0 40.5
Line 6 20.2 60.7 101.2 40.5 101.2 30.4 40.5 60.7
Fortøyningsliner

Line 7 20.7 62.1 103.6 41.4 103.6 31.1 41.4 62.1

Line 8 19.8 59.5 99.2 39.7 99.2 29.8 39.7 59.5
Line 9 13.9 41.6 69.3 27.7 69.3 20.8 27.7 41.6
Line 10 7.2 21.7 36.2 14.5 36.2 10.9 14.5 21.7
Line 11 10.0 30.1 50.2 20.1 50.2 15.1 20.1 30.1
Line 12 9.8 29.4 49.0 19.6 49.0 14.7 19.6 29.4
Line 13 9.8 29.5 49.2 19.7 49.2 14.8 19.7 29.5
Line 14 10.4 31.2 52.0 20.8 52.0 15.6 20.8 31.2
Line 15 17.4 52.1 86.9 34.7 86.9 26.1 34.7 52.1
Line 16 16.5 49.4 82.4 33.0 82.4 24.7 33.0 49.4
Line 17 17.4 52.3 87.2 34.9 87.2 26.2 34.9 52.3
Line 18 13.8 41.4 69.0 27.6 69.0 20.7 27.6 41.4
Chain and chain

Coupling plates
and steel joints
Rope with knot

components

attachments
Used chain
axial force
Max. dim.

Shackles

Bottom
Rope

Component

[tonnes] [tonnes] [tonnes] [tonnes] [tonnes] [tonnes] [tonnes] [tonnes]

Table 27 shows the dimensioning forces and associated MBLs for both ULS and ALS conditions. In cases
where the MBL from the ALS analyses exceeds that of the ULS analyses, the cell is coloured in yellow.

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11 Conclusion
The maximum design force in the ultimate limit state (ULS) occurs in frame C1-C2 with 29.1 tonnes. The
highest design force in the accidental limit state (ALS) is of 26.7 tonnes in line 3a. The maximum design
force acting on the floating pens in the ULS reaches 11.5 tonnes and 12.5 tonnes in the ALS. Actions
must be taken to increase the capacity of buoy D1.

It is assumed that the anchoring points are installed and checked for strength.

12 References
AKVA group ASA. (2012). Brukermanual Merder. Mo i Rana: AKVA group ASA.

NS 9415:2009 Marine fish farms - Requirements for site survey, risk analyses, design, dimensioning,
production, installation and operation. (2009). Standard Norge.

Recommended Practice, DNV-RP-C203, Fatigue design of offshore steel structures. (2010). Det Norske
Veritas.

Wind & weather statistics. (2017, 06 18). Retrieved from Windfinder:

https://www.windfinder.com/windstatistics/san_carlos_guaymas

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