BP

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TECHNICAL NOTE
To Bluewater Energy Services Attn. Kees van Beveren
Email addrs Kees.vanBeveren@bluewater.com cc
cc jb@globalmaritime.co.uk
From Jason Bell Pages 6 Date 25 Jun 2013
Reference TN_24138_1
Subject Haewene Brim Bollard Pull Calculations
Introduction
Global Maritime Scotland Ltd (GM) has been requested by Bluewater Energy Services (BES) to carry
out a bollard pull calculation for the Haewene Brim FPSO.
The scope of work and deliverables are detailed in proposal P13854 Ref[1].
The calculations are based on DNV Rules for Planning and Execution of Marine Operations Ref[2],
DNV RP-H103 Ref[3] and DNV OS-C301 Ref[4].
BES has informed GM that the contracted tow tug is the BB Troll with bollard pull of 165 tonnes.
Requirements
As per Ref[2] the towing force requirement for open sea is to be sufficient to maintain zero speed
under the environmental conditions shown in Table 1.
Environmental Condition Value
Wind Velocity (Vw) 20 m/s
Head Current Velocity (Vc) 1 m/s
Significant Wave Height (Hs) 5 m
Table 1: Environmental Conditions
Ref[2] also states that for coastal tows in narrow or shallow waters the bollard pull shall be sufficient
to maintain a speed over ground of 2 knots under defined environmental conditions. The
environmental conditions here will conservatively be taken as those stated in table 1.
Environmental Force Calculations
The three main environmental forces required for the bollard pull calculation are Wind, Current and
Wave Drift forces. The equations for calculating these forces are detailed in Ref[3] and[4] and
summarised as follows:

2. TN_24138_1 Page 2 of 6
Wind Force
The formula for the wind force is shown below:
ࡲ࢝ =
ሺ૙. ૞ ∗ ࡯࢙ ∗ ࡯ࢎ ∗ ࣋ ∗ ࢂ૛
∗ ࡭ሻ
ࢍ
Where:
Fw = Wind force [tonnes]
Cs = Shape coefficient
Ch = Height coefficient
ρ = Density of air [t/m3
]
V = Wind velocity [m/s]
A = Projected area of all exposed surfaces [m2
]
g = Gravity [m/s2
]
Current Force
The formula for calculating the current force is shown below:
ࡲࢉ =
ሺ૙. ૞ ∗ ࣋ ∗ ࡯ ∗ ࢂ૛
∗ ࡭ሻ
ࢍ
Where:
Fc = Current force [tonnes]
ρ = Density of water [t/m3
]
C = Current force coefficient
V = Current velocity [m/s]
A = Wetted surface area of hull [m2
]
g = Gravity [m/s2
]
Wave Drift Force
The formula for wave drift force is shown below:
ࡲ࢝ࢊ =
૚
ૡ
∗ ࣋ ∗ ࡾ૛
∗ ࡮ ∗ ࡴ࢙
૛
Where:
Fwd = Wave drift force [tonnes]
ρ = Density of water [t/m3
]
R = Reflection coefficient
B = Breadth of towed object
Hs = Significant waveheight [m]

3. TN_24138_1 Page 3 of 6
Projected Areas
Wind and current loading areas have been measured using a forward profile drawing of the vessel,
supplied by BES, at a tow draught of 7m.
A projected wind and current area drawing is shown in Appendix B.
Bollard Pull
The required bollard pull to maintain zero speed under the environmental conditions stated in Table 1
is calculated as 117 tonnes. This includes a tug efficiency factor of 0.75 as recommended for offshore
tows in Ref[2].
An additional check with the vessel towed at a speed of 2 knots has been performed. Conservatively
the environmental conditions stated in Table 1 are also adopted here. The required bollard pull here is
calculated at 149 tonnes.
The bollard pull calculation spreadsheet is included in Appendix A.
Conclusion
The calculations show that the BB Troll has sufficient bollard pull capacity to satisfy the DNV code
requirements for the Haewene Brim tow operation.

4. TN_24138_1 Page 4 of 6
References
[1] GM Proposal P13854 Haewene Brim Bollard Pull Calculations, June 2013.
[2] DNV Rules for Planning and Execution of Marine Operations, 1996 Revision, January 2000.
[3] DNV RP-H103 Modelling and Analysis of Marine Operations, April 2011.
[4] DNV-OS-C301 Stability and Watertight Integrity, DNV, April 2011.

5. TN_24138_1 Page 5 of 6
APPENDIX A
Bollard Pull Calculation Spreadsheet

6. BOLLARD PULL CALCULATIONS
VESSEL NAME: Haewene Brim BEAM 42.00 m
DRAUGHT 7.00 m
LENGTH 252.00 m
DEPTH 20.50 m
ϱair 0.00122 tonnes/m
3
ϱwater 1.025 tonnes/m3
g (acceleration) 9.81 m/s
2
Wave Drift Coefficients
From DNV RP-H103 April 2011
Table 7-1 Typical reflection Coeffircients "R"
1) Wave Drift Force Square Face 1.00
Condeep Face 0.97
R 0.45 Vertical Cylinder 0.88
Hs 5.00 DNV Marine Ops Pt.2 Ch. 2 Sect. 3.3.2.4 Barge with Raked Bow 0.67
Barge with Spoon Bow 0.55
WAVE DRIFT FORCE = 27.24 tonnes DNV RP-H103 Sect. 7.2.6.4 Ship Bow 0.45
Wind Coefficients
2) Wind Force From DNV OS-C301 April 2011
Table B1 Values Wind Force Shape Coefficient (Cs)
WIND SPEED 20.00 m/s Shape Cs
Spherical 0.4 0.40
AREA (Hull MSL to 15.3m) 641.94 m^2 Cylindrical 0.5 0.50
Cs 1.00 Large flat surface (hull, deckhouse, smooth under-deck areas) 1.0 1.00
Ch 1.00 Drilling derrick 1.25 1.25
Wires 1.2 1.20
Hull and Main Decks (15.3 to 30.5m) 619.86 m^2 Exposed beams and girders under deck 1.3 1.30
Cs 1.00 Small parts 1.4 1.40
Ch 1.10 Isolated shapes (crane, beam, etc.) 1.5 1.50
Clustered deckhouses or similar structures 1.1 1.10
Deckhouse (30.5 to 46m) 274.30 m^2
Cs 1.10 Table B2 Values Wind Force Height Coefficient (Ch)
Ch 1.20
Height above sea level (metres) Ch
Deckhouse surr. Structure (30.5 to 46m) 38.32 m^2 0 - 15.3 1.00
Cs 1.10 15.3 - 30.5 1.10
Ch 1.20 30.5 - 46.0 1.20
46.0 - 61.0 1.30
Equipment on Deckhouse (30.5 to 46m) 26.06 m^2 61.0 -76.0 1.37
Cs 1.40 76.0 - 91.5 1.43
Ch 1.20 91.5 - 106.5 1.48
106.5 - 122.0 1.52
Equipment on Deckhouse (46 to 61m) 19.54 m^2 122.0 - 137.0 1.56
Cs 1.40 137.0 - 152.5 1.60
Ch 1.30 152.5 - 167.5 1.63
167.5 - 183.0 1.67
Flare Towers (30.5 to 46m) 23.03 m^2 183.0 - 198.0 1.70
Cs 1.25 198.0 - 213.5 1.72
Ch 1.20 213.5 - 228.5 1.75
228.5 - 244.0 1.77
Flare Towers (46 to 61m) 65.37 m^2 244.0 - 256.0 1.79
Cs 1.25 Above 256 1.80
Ch 1.30
Current Coefficients
Flare Tower (61 to 76m) 41.27 m^2 Hull Type Cd
Cs 1.25 SPOON BOW / FAIRED STERN 0.20
Ch 1.37 SPOON BOW / RAKED STERN 0.35
RKD BOW / RKD/SQU STERN 0.50
Exhaust Towers (30.5 to 46m) 71.52 m^2
Cs 1.00
Ch 1.20
WIND FORCE = 52.64 tonnes DNV-OS-C301Section B 100
3) Current/Speed Force
VESSEL/ CURRENT SPEED 1.00 m/s
Cd 0.50
BOW AREA 292.74 m^2
CURRENT FORCE = 7.65 tonnes DNV RP-H103 Sect. 3.2.4
4) Bollard Pull
Static Bollard Pull 87.53 tonnes
Required Bollard Pull 116.71 tonnes
(with tug efficiency of 0.75)
Global Maritime Filename: Haewene Brim BP Calc (updated 24.06.13) Page: 1

7. BOLLARD PULL CALCULATIONS
VESSEL NAME: Haewene Brim BEAM 42.00 m
DRAUGHT 7.00 m
LENGTH 252.00 m
DEPTH 20.50 m
ϱair 0.00122 tonnes/m3
ϱwater 1.025 tonnes/m3
g (acceleration) 9.81 m/s2
Wave Drift Coefficients
From DNV RP-H103 April 2011
Table 7-1 Typical reflection Coeffircients "R"
1) Wave Drift Force Square Face 1.00
Condeep Face 0.97
R 0.45 Vertical Cylinder 0.88
Hs 5.00 DNV Marine Ops Pt.2 Ch. 2 Sect. 3.3.2.4 Barge with Raked Bow 0.67
Barge with Spoon Bow 0.55
WAVE DRIFT FORCE = 27.24 tonnes DNV RP-H103 Sect. 7.2.6.4 Ship Bow 0.45
Wind Coefficients
2) Wind Force From DNV OS-C301 April 2011
Table B1 Values Wind Force Shape Coefficient (Cs)
WIND SPEED 20.00 m/s Shape Cs
Spherical 0.4 0.40
AREA (Hull MSL to 15.3m) 641.94 m^2 Cylindrical 0.5 0.50
Cs 1.00 Large flat surface (hull, deckhouse, smooth under-deck areas) 1.0 1.00
Ch 1.00 Drilling derrick 1.25 1.25
Wires 1.2 1.20
Hull and Main Decks (15.3 to 30.5m) 619.86 m^2 Exposed beams and girders under deck 1.3 1.30
Cs 1.00 Small parts 1.4 1.40
Ch 1.10 Isolated shapes (crane, beam, etc.) 1.5 1.50
Clustered deckhouses or similar structures 1.1 1.10
Deckhouse (30.5 to 46m) 274.30 m^2
Cs 1.10 Table B2 Values Wind Force Height Coefficient (Ch)
Ch 1.20 Height above sea level (metres) Ch
0 - 15.3 1.00
Deckhouse surr. Structure (30.5 to 46m) 38.32 m^2 15.3 - 30.5 1.10
Cs 1.10 30.5 - 46.0 1.20
Ch 1.20 46.0 - 61.0 1.30
61.0 -76.0 1.37
Equipment on Deckhouse (30.5 to 46m) 26.06 m^2 76.0 - 91.5 1.43
Cs 1.40 91.5 - 106.5 1.48
Ch 1.20 106.5 - 122.0 1.52
122.0 - 137.0 1.56
Equipment on Deckhouse (46 to 61m) 19.54 m^2 137.0 - 152.5 1.60
Cs 1.40 152.5 - 167.5 1.63
Ch 1.30 167.5 - 183.0 1.67
183.0 - 198.0 1.70
Flare Towers (30.5 to 46m) 23.03 m^2 198.0 - 213.5 1.72
Cs 1.25 213.5 - 228.5 1.75
Ch 1.20 228.5 - 244.0 1.77
244.0 - 256.0 1.79
Flare Towers (46 to 61m) 65.37 m^2 Above 256 1.80
Cs 1.25
Ch 1.30
Current Coefficients
Flare Tower (61 to 76m) 41.27 m^2 Hull Type Cd
Cs 1.25 SPOON BOW / FAIRED STERN 0.20
Ch 1.37 SPOON BOW / RAKED STERN 0.35
RKD BOW / RKD/SQU STERN 0.50
Exhaust Towers (30.5 to 46m) 71.52 m^2
Cs 1.00
Ch 1.20
WIND FORCE = 52.64 tonnes DNV-OS-C301Section B 100
3) Current/Speed Force
VESSEL/ CURRENT SPEED 2.03 m/s 2 knots vessel speed + 1 m/s current
Cd 0.50
BOW AREA 292.74 m^2
CURRENT FORCE = 31.47 tonnes DNV RP-H103 Sect. 3.2.4
4) Bollard Pull
Bollard Pull 111.36 tonnes
Required Bollard Pull 148.48 tonnes
(with tug efficiency of 0.75)
Global Maritime Filename: Haewene Brim BP Calc (updated 24.06.13) Page: 1

8. TN_24138_1 Page 6 of 6
APPENDIX B
Projected Areas