Welcome to the Bollard Pull Calculator for Barges - Rev 02

What does this Excel Sheet do?

This Excel sheet helps you calculate the Required Bollard pull of a Tug used for towing a Barge

How is the Excel Sheet Organised?

The Excel Sheet provides four different methods for calculations.

The First Method is based on DNV rules for Marine Operations. This is contained in the sheet named "Bollard Pull - DNV"

The Second Method is using industry standard OPL Guidelines for Barge Transportation Vol 5. This is contained in the sheet named "Bollard Pull - OPL Guideline"

The Third Method is based on Bureau Veritas rules and formulas for Bollard Pull Calculations. This is contained in the sheet named "Bollard Pull - BV"

The Fourth method is using a simple Empirical formula. This is contained in the sheet named "Empirical Formula". It provides Bollard Pull for different weather conditions: Calm, Rough and Extreme

How to use this Excel SheetIn all the three methods, the user is asked for some inputs to be provided. For example, the Wetted Surface area of Barge, Wind Speed etc. The Input cells are highlighted in blue.The user has to provide all the inputs highlighted in blue.For some inputs, Tables and charts are required to be referred. These Tables and charts are provided alongwith for the user to enter these inputs.Once all inputs are provided, the components of required bollard pull are calculated and added up to give the final Bollard Pull required.

Change log Rev 021. DNV Formula - Added Wave Resistance now based on DNV-RP-H1032. References updated for DNV method3. OPL method - Wave effect resistance is now being automatically calculated, and user need not input it4. OPL method - some typo errors rectified

Spherical 0.4

Parameter Notation Value Units Cylindrical 0.5Air Density ρa 1.225 kg/m

3Large flat surface (hull, deckhouse, smooth under deck areas) 1

Sea Water Density ρw 1025 kg/m3

Drilling derrick 1.25

Acc. Due to Gravity g 9.81 m/s2

Wires 1.2

3.88 MT Exposed beams and girders under deck 1.3

Small parts 1.4

Parameter Notation Value Units Isolated shapes (cranes, beam, etc) 1.5

Length L 116.00 m 0.00 MT Clustered deck houses or similar structures 1.1

Breadth B 36.60 m

Depth D 7.00 m 3.88 MT Reference: ABS, 2016, Rules for Building and Classing Mobile Offshore Drilling Units, Part 3 Chapter 1,

Draft (Mid) T 3.00 m Section 3, ‘Environmental Loadings’, p.11.

Type of Bow (1 - Square face, 2 -

Raked, 3 - Spoon, 4 - Ship Shape)3

Freeboard f 4.00 m

Hull Windage Area AWH = B X f 146.40 m2

1.43 MT

Hull Underwater Area ACH = B X T 109.80 m2

1.00

Current Drag Coefficient (Hull) CD 1.00 Over Not exceeding Ch 0.97

0 15.3 1 0.88

315.3 30.5 1.1 0.67

0.55 30.5 46 1.2 0.55

35.46 MT 46 61 1.3 0.45

Parameter Notation Value Units *Reference: DNV RP-H-103, Sec 7.2.6.4 61 76 1.37

Breadth Overall Bc 0.00 m 76 91.5 1.43

Height Overall Hc 0.00 m 91.5 106.5 1.48 Reference, DNV-RP-H103, 2011, Table 7-1

Height Coefficient Ch 1.10 See Table 1 106.5 122 1.52

Shape Coefficient Cs 1.00 See Table 2 3.88 MT 122 137 1.56

Cargo Windage Area AWC = BC X HC 0.00 m2

1.43 MT 137 152.5 1.6

35.46 MT 152.5 167.5 1.63

40.78 MT 167.5 183 1.67

183 198 1.7

Parameter Notation Value Units 198 213.5 1.72

Wave Height HS 5.0 m 0.75 213.5 228.5 1.75

Current Speed VC 0.5 m/s **Reference: DNV Rules for Marine Operations Pt2 Ch2, Towing, 3.3.2.6 228.5 244 1.77

Wind Speed VW 20.6 m/s 244 259 1.79

259+ 1.8

54.37 MT

Parameter Notation Value Units Use Centre of Area for Above Heights

Actual Bollard Pull of Tug BPT 60.0 MT Reference: ABS, 2016, Rules for Building and Classing Mobile Offshore Drilling Units, Part 3 Chapter 1,

Tug Efficiency η 0.75 Section 3, ‘Environmental Loadings’, p.11.

Change Log (Rev 02)

1. DNV Calculation now based on DNV-RP-H-103, the latest document from DNV which replaces the earlier Rules for Marine Operations (2000)

Table 2: Height Coefficient

Current Resistance FC

Fc

CARGO

FW = FWH + FWC

Ch: Height Coefficient

Height above sea level (metres)

TUG EFFICIENCY

SEA STATE

TOTAL RESISTANCE, FT = FW + FC + FD

INPUTS REQUIRED BOLLARD PULL CALCULATION FOR BARGES TOW PULL CALCULATION - DNV METHOD

This method is based on DNV Recommended Practice RP-H103 7.2.6 (Applicable for zero towing speed).

Shape and Height coefficients are taken from ABS MODU Rules 2016

Table 1: Shape Coefficient

Summary: This method calculates the Required Bollard Pull to hold the tow in a given Sea State. The Standard Sea State

used is Hs = 5m, Current = 1 kn and Wind =40 Kn. Directions: The applicability of the method is shown in the box titled

"Applicability Check" on the left. All input cells are in blue. Tug efficiency can be varied. Coefficients Cs and Ch can be

obtained from the Tables on the right.

Wind Resistance, FW = FWH + FWC

FWH = Wind Resistance for Hull

FWH = 1/2 x ρa x VW2 x AWH

FWH

REQUIRED BOLLARD PULL 54.37 MT

Cs : Shape Coefficient

GENERAL

BARGE

FWC = 1/2 x ρa x VW2 x AWC x Ch x Cs

FWC = Wind Resistance for Cargo

FC = 1/2 x ρs x CD x VC2 x ACH

Tug Efficiency, η**

Current Resistance, FC

Wind Resistance, FW

Wave Drift Resistance, FD

Total Resistance, FT

FD

Reflection coefficient, R (See Table 3)

FW = Total Wind Resistance

FWC

BPTUG

Since Required Bollard Pull < Actual Bollard Pull => OK

REQUIRED BOLLARD PULL (BP = FT / η )

Wave Drift Resistance (FWD)*

FWD = 1/8 x ρs x R2 x B x HS

2

Type of Bow (1 - Square face, 2 - Raked,

3 - Spoon, 4 - Ship Shape)

Barge with Spoon bow

Ship bow

Table 3: Reflection Coefficients

R: Reflection Coefficients

Square Face

Condeep base

Vertical Cylinder

Barge with Raked bow

Cargo Breadth = BC

Cargo Height Hc

Cargo Windage Area AWC= BC X HC

Hull Windage Area AWH= B X f

Draft ,T

Depth, DFreeboard, f = D -T

Hull Underwater Area, ACH = B X T (approx.)

Breadth, B

Sectional View of Barge with Cargo

BARGE NAME Directions:1. Fill the input cells which are in blue.

TOWING SPEED -----> knots 5.0 2. The outputs will show in the bottom as the final Bollard Pull required.Actual Bollard Pull of Tug -----> tonnes 60.0Towing Efficiency in % (Default value 75%) 75.0

3. Use Table 1 for calculating the Height coefficient for Wind

4. Use Table 2 for finding the Shape Coefficient for windUnit Value 5. Use Table 3 to calculate the Wave Effect Resistance which depends on the wave height.

Fouling coefficient(0.4 clean hull, 0.85 fouled hull, usually

0.625)f1 - 0.63

In case the value of Wave Height falls in between two values given in the table, interpolation is to be used

Wetted Surface of the Hull S ft2 55553.34

Still water tow speed in knots v knots 5.0

Frictional Resistance RF tonnes 10.94

Unit Factor

feet 1

Unit Value feet 1.1Hull Shape Coefficient (0.20 for rake ended barges and bluff

bowed vessels and 0.50 for square bowed vessels) f2 - 0.2feet 1.2

Transverse Area(Underwater) AT ft21181 feet 1.3

Still water tow speed in knots v knots 5.0 feet 1.4

Wave Forming Resistance RWF tonnes 9.17 feet 1.5

feet 1.6

Table 1: Cargo Height Coefficient for Wind Calculations

Unit ValueHeight Coefficient for Cargo Exposed to Wind (See Table 1) Ch - 1Shape Coefficient for Cargo Exposed to Wind (See Table 2) Cs - 1

Cargo Transverse Area (Exposed to wind) AC ft20.0 Cs

Vessel Transverse Area (Exposed to wind) AH ft21575.0 0.5

Total Transverse Area AT ft21575.0 Flat Perpendicular Surface 1

Wind Velocity vW knots 40.0 1.5

Still water tow speed in knots v knots 5.0 1.3

Wind force RW tonnes 4.92 1.25

0.4

Table 2: Carge Shape Coefficient for Wind Calculations

Unit Value

Wetted Surface of the Hull S ft2 55553

Current Speed vC knots 1.0

Current Effect Resistance RC tonnes 0.40

5 feet 2000 lbs

10 feet 12000 lbs

15 feet 22000 lbs

Unit Value 20 feet 29000 lbs

Wave Height ft 16 25 feet 30000 lbs

Force at 16 feet wave - See Table 3 FWR lbs 23,400 30 feet 33000 lbs

Wave Effect Resistance RWH tonnes 10.62

Table 3: Wave Effect Resistance Table

Unit Value

Frictional Resistance RF tonnes 10.9

Wave Forming Resistance RWF tonnes 9.2

Hawser Resistance RH tonnes 2.01

Frictional Resistance RF tonnes 10.94

Wave Forming Resistance RWF tonnes 9.17

Wind Resistance RWH tonnes 4.92

Current Effect Resistance RC tonnes 0.40

Wave Effect Resistance RWH tonnes 10.62

Hawser Resistance RH tonnes 2.01

Total Resistance RT tonnes 38.1

Tug Efficiency in percentage(Default value 75%) η 75.0

Required Bollard Pull = (RT/η)*100 BP TONNES 50.74

Actual Tug Bollard Pull TONNES 60.00Satisfied/Not Satisfied? Yes

Wave Height Effect – For wave Force on Hull:

Significant Wave Height Added Resistance

Height

0-50

50-100

100-150

150-200

200-250

250-300

300-350

Derrick (latticed structures)

Sphere

Shape

Factor Ch (Height coefficient for wind calculations)

Factor Cs (Shape coefficient for wind calculations)

Cylinder

Isolated Structure – Beam-channel angle braces

Exposed Beams

RT = RF + RWF + RW + RC + RWH + RH

RWF = 3.42 (f2)(AT)(v)2 , lbs.

RC = 0.016 (S)(vC)2 , lbs.

Description

Description

Calculation of Wave Effect

Calculation of Hawser Resistance:

CALCULATION OF REQUIRED STATIC BOLLARD PULL FOR BARGE: OPL Guidelines

Description

Description

Description

Description

BARGE 1

Reference: OPL Oilfield Seamanship Series - Volume 5: Barge Moving

Calculation of Frictional Resistance:

Calculation of Wave Forming Resistance:

Calculation for Wind Resistance:

Calculation of Current Effect

RW = 0.0034 (AT)(vW+v)2 , lbs.

RF = f1 (S)(v/6)2 , lbs.

OUTPUTS

Calculation of Total Resistance:

From Table 3

RH = 0.10 (RF + RWF)

Directions:

BARGE NAME: BARGE 1 1. Fill the input cells which are in blue.

2. The output will show in the bottom as the final Bollard Pull required.INPUTS 3. Use Appendix 1 for calculating the coefficients Cx and Ch

Symbol Value Unit Description 4. Use Graph 1 below for finding the value of Rv/DL = 116.00 m Waterline LengthB = 36.60 m Breadth

T = 3.00 m Draft APPENDIX 1: Tables for Cx and ChV = 5 Kn Vessel Speed (Towing Speed)Vc = 1 Kn Assumed Current Speed D = 11463 t DisplacementS = 146.4 m^2 Windage Aread = 65 mm Tow Line Diameterl = 700 m Tow Line Immersed LengthZ = 1 m Sag of Tow LineP = 900 m Tug to Towed Vessel DistanceN = 150 days Number of Days Elapsed Since last Dry Docking

Vfr = 18 Kn Maximum Towing Vessel Speed in Free Runrsw = 1.025 t/m^3 Sea Water Specific Gravity (default value 1.025)rair = 1.22 kg/m^3 Air Specific Gravity (default value 1.22)n = 1.2E-06 m^2/s Viscosity (default value 1.2 10^-6)

Vw = 40 Kn Wind Speed (default value 40)BPt = 60 Tonnes Actual Bollard Pull of Tug

Symbol Value Unit Description

Rf = ½ Cf (rsw)(Sw)(v)2

R = 298375200 Reynolds Number, R = vL / ν

Cf = 0.001789 Friction Coefficient, Cf = 0.075 / [log10 R)-2]2

DCf = 0.002147 Addition to Friction Coefficient due to Hull Fouling, DCf = 0.008 (N)(Cf)Cft = 0.004336 Total Friction Coefficient, Cft = Cf + DCf +0.0004Sw = 4485.44 m^2 Wetted Surface Area

Rf = 94961 N Frictional Resistance

L/B = 3.17B/T = 12.20

V/(L)^0.5 = 0.29Rv / D = 12.00 (To be taken from the Graph 1 on the right)

Rv = 137556 N Wave Resistance

Rh = 232517 N Total Hydrodynamic Resistance

Ra = ½ Cx * Ch * (rair)(S)(Vw)2

Cx = 1 Drag Coefficient(To be taken from the Appendix1 on the right)Ch = 1 Height Coefficient(To be taken from the Appendix1 on the right)Ra = 37815 N Aerodynamic Resistance

Rr = 4.6 x10-3 (d)(v)2( l + (71.6 Z/P)) , in Newton

Rr = 1994 N Tow Line Resistance

Rtot = 272325 N

(V+Vc)/Vfr = 0.33 Graph1: Graph for Values of Rv/DCef = 0.67 Percentage of Static Bollard Pull = (1 - (V+Vc)/Vfr)

Rt = 41.6 T

BPt = 60.0 T

Satisfied/Not Satisfied Yes

Actual Bollard Pull for Tug, BPt

Tow Line Resistance Rr

Total Resistance of Towed Vessel

Bollard Pull Coefficients

Total Required Static Bollard Pull for Tug, Rt

Aerodynamic Resistance Ra

CALCULATION OF REQUIRED STATIC BOLLARD PULL FOR BARGE: BV Rules and Formulas

RESULTS

Frictional Resistance Rf

Wave Resistance Rv

Total Hydrodynamic Resistance Rh

FORMULA USEDINPUTS: Please input the following Using Empirical Formula for towing guide by Port Authorities

Unit Value

BARGE 1 BP = { [ (∆⅔ · (v3/ (120 · 60)) ] + (0.06B · D1) } · K (tonnes)

m 116.00m 36.60 Where:

tonnes 11463.00 ∆ = full displacement of towed vessel, in tonnesm 7.00 v = tow speed, in knots

m 3.00 B = breadth of the vessel, in meters

m 0.00 D1 = depth of exposed transverse section of the vessel including

75.00 deck cargo above the water line, in meters

Yes/No Notonnes 60.00

BP = Required bollard pull, in tonnes

Note: For tow by the stern, then the Bollard Pull requirement is to be increased by 20% K = the factor depending on the likely condition to be met. This factor is

intended to reflect desired weather margins.

OUTPUTS: CALCULATED BOLLARD PULL WITH VARIOUS WEATHER CONDITIONS & TOWING SPEEDS In General: • for exposed tows, K = 1.0 - 3.0

• for sheltered tows, K = 0.75 - 2.0

Good Rough Extreme • for protected tows, K = 0.50 - 1.5

116.00 116.00 116.005.00 4.00 3.00 <---- Please input the different speeds considered for the three weather conditions

36.60 36.60 36.6011463.00 11463.00 11463.00

7.00 7.00 7.003.00 3.00 3.000.00 0.00 0.004.00 4.00 4.001.00 2.00 3.00

17.89 26.89 32.2575.00 75.00 75.00

23.85 35.86 43.00

No No No23.85 35.86 43.0060.00 60.00 60.00

SATISFIED SATISFIED SATISFIED

Actual TUG Bollard Pull

Tow by Stern?Final Bollard Pull, BP (in tonnes)

CALCULATION OF REQUIRED STATIC BOLLARD PULL FOR BARGE: Empirical Formula

Required Bollard Pull as per formula, RtTug Efficiency in percentage(Default 75%), ηBollard Pull considering Tug Efficiency =

(RT/η)*100

Description

Length, LTowing Speed, VBreadth, BDisplacement, ∆

Actual TUG Bollard Pull

Description

Length, LBARGE NAME

Breadth, BDisplacement, ∆Depth, DDraft, dCargo Height, HTug Efficiency in percentage(default 75%)Is it Tow by Stern?

Depth, DDraft, dCargo Height, HExposed Height, D1Weather Factor, K

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