ballast calculation

HHI – CHEVRONTEXACO ESCRAVOS GAS PROJECT PHASSE 3 ONSHORETENDER DOCUMENT BALLASTING PLAN AND CALCULATION

COMPANY: CHEVRON TEXACO NIGERIA LIMITED

CONTRACTOR: HYUNDAI HEAVY INDUSTRIES

SUBCONTRACTOR: INERGEY ENGINEERING AND CONSTRUCTION CO. LTD.

TENDER NO:

WECO JOB NO: 003-004

FORESCRAVOS GAS PLANT EGP - 3

PIPE RACKS AND MUDULES FABRICATION, MODULARIZATION AND INSTALLATION

Rev No

Date Author Endorsed by

WECO

Endorsed by

Customer

Purpose of Issue

0 25 FEB 2003

UHM For Bid Document

BALLAST PLAN AND CALCULATION


1.0 INTRODUCTION

This document presents results of tidal variations monitored at Aker Base for a Period of two weeks, and a preliminary ballasting calculations to show compatibility of bardge/quary at two extreme conditions: the low water tide and the high water tide. Calculations are based on the Loadout Arrangement Block Diagram provided by the transportation and Installation Contractor. Detailed calculations will be provided after the Transportation and installation contractor has provided AFC loadout and sea fastening and barge drawings.It is assumed that the cargo barge Tide Mar 254 ( 250’x72’x16’ )will be used.

2.0 TIDAL VARIATIONS AT AKER BASE

A tide gauge has been established on October 16,1999 at the quay of Aker base and regular readings are taken every day for a period of two weeks. Details of the readings are hereby attached (Appendix 1). All readings are above LLW.It has been observed 11/2 to 2 hours of relatively steady tide(+/-10cm).This would be the ideal period for the loadout operation.

The Aker Base quay elevation is 3.58 above LLw. At the highest tide the water level was about 2.32m above LLW, therefore 1.26m below quay level. At the lowest tide the water level was at LLw (0.0m), therefore 3.58m below quay level.

The two main water levels studies (low and high water) are llustrated in figure 2.1 and 2.2.

3.0 HYDROGRAPHIC SURVEY (SOUNDING) OF AKER BASE

In order to ascertain the compatibility of the depth of Aker base Jetty/Barge maximum draft, hydrographic survey map has been made available, the results of the survey show an average depth of 7.0m below LLW, which is more than enough to accommodate the Cargo Barge which maximum draft is 3.87m.


3.0 Cargo Barge Dimensions and Ballast Tanks Arrangement

3.1 Barge Dimensions

Length overall 250.0 ft 76.20m

Beam 72.0 ft 21.20m

Depth 16.0 ft 4.88m

Light draft 2.20 ft 0.67m

Maximum draft 12.6 ft 3.87m

Freeboard 3.35 ft 1.02m

Light displacement 2610 kips 945.6 tonnes

Displacement @ design draft

5,710.0lt 5,801.36 t

Deadweight 4,780.0lt 4,856.40 t

Deck Space 230 x 68 ft 70.1 x 20.7m

Deck Strength 1,500.lb/ft2 7.30 t/m2

3.2 Ballasting Tanks Arrangement

To achieve the required ballasting, all tanks have been assigned explicit purposes. These assignments are illustrated in figure 3.1.It is assumed that all thanks will have at least 2.5% or about 5 inches of water in them (this accounts for mud or excess water pumps cannot remove).


4.0 Parabe Quarters Ballasting at Phrase 05.0

The ballasting at phase 0 takes place after the loading by crane of piles (P1, P2, P3) and the bridge, it aims at leveling the main deck of the cargo barge with the quay. We will consider therefore the two extreme cases the low tide and the high tide.

4.10 Piles, Bridge, Lightship dataThe piles, Bridge and lightship data have been estimated approximately based on the loadout block diagram provided by the transportation and installation contractor.

Item Weight (kips) X (ft) Y (ft)Lightship 2610 0.0 0.0P.Q piles 501.52 -54.8 -7.71P.Q Bridge 39.6 -73.0 22.5Note: Coordinates are in reference to mid-ship

Using a geometrical analogy, it was established that the waterline length at the design draft is 243 ft.The mass displacement of the barge when loaded with the pipes and the bridge is 3,151.12 kips (1,141.71 tonnes). This correspond to a volume displacement of 1,114 m3, using seawater density of 1.025 t/m3.For this given load, we resort once more to the geometrical analogy to determine the waterline length, LWLa and the corresponding draft.

Llw =63.58m(208.6 ft) d1 = 1.03m (3.38 ft)

We can now estimate the excess height and the corresponding volume of water to ballast so that the deck of the badge with the quay. We shall therefore consider separately the low and high tide scenario.

4.2 Low Tide

42.1 Levelling of barge with quay

At the lowest tide the water level is 3.58m below quay level, knowing the depth of the barge H, and the draft d1,we can obtain the excess height h 1, as:


h1= H-d1- 3.58 = 4.88 – 1.03 – 3.58 = 0.27mh1 = 0,27m (0.89ft)

To align the deck with the quay we need to pump into the barge a certain volume of water such that the dreft of the barge will be:

d2 = d1 + h1 = 1.03 + 0.27 = 1.30m (4.27ft)

With the corresponding waterline length Lw12 =64.47m (211.52ft) we can now obtain the volume displacement both at d1 and d2 drafts.The displacement at d1 is 1 = 1,399.13m3

The displacement at d2 is 2 = 1,777.59m3

The required volume of water to pump into the barge is obtained as

V1 =1 -2 = 1,777.59 – 1,399.13 = 378.46m3

V1 =378.46m3 = 13,365.19ft3 (855.4 kips)

4.2.2 Heel and Trim correction

The loading of the piles and the bridge will generate trim and heel that must be corrected before the loading of the jacket.

4.2.2.1 Trim correction

We can see from the Weight calculation that the longitudinal Center of Gravity (XCG) has shifted by 9.64ft towards the stern,this must be corrected.

a. Determination of the moment to change trim (MCT)

MCT =( x GML ) / Lpp

Where : the mass displacement (kips) GML : Longitudinal Metacentric height (ft)

L pp : Length between perpendiculars (ft)

MCT = ( 3151.12 x 1493 .4) /246.5

= 19090.8 kips / ft

b. Determination of the total trim

Total trim = (LCG – LCB ) x / MCT = ( -9. 64 X 3151.12 )/ 19090.8


= -1.59 FTThere is a trim of 1.59 ft by the stern. To eliminate it, we need to pump a certain amount of water into the control tank (1c) located at the bow.

a. Determination of the amount of water to transfer to tank 1c

w = (GGi x W)( GGi – d)

where GGi : the trimming lever (ft)w : weight (amount of water ) to add. (kips)W : Mass displacement (kips)D : trimming distance (ft)

W = (-9.64 x 3151.12)/(-9.64 – 64) = 412 kips 6437 ft3

To correct the trim we need:

V2 = 6,437 ft3

4.2.2.1 Heel correction

We can see from the weight calculations that the transverse center of Gravity (YCG) has shifted by 0.94ft towards the starboard, this must be corrected.

a. Determination of the moment to change heel (MCH)

MCH = ( x GMT )/L pp

Where : mass displacement (kips)GMT : Transvers Metacentric height (ft)B : Beam (ft)

MCH = (3,151.12 X 123.9 )/72= 5,422.55 KIPS/FT

b. determination of the total Heel

Heel = (TCG – TCB ) x MCH = ( -0.94 x 3,151.12 )/5,422.55 = -0.55ft

There is a heel of 0.55ft by the starboard side. To eliminate it, we need to pump certain amount of water into the heel control tank (3p) located at the port side.


b. Determination of the amount of water to transfer to tank 3p

W = ( GGi x W )/(GGi – d )

Where GGi : heeling lever (ft)w : weight (amount of water) to addW : mass displacement (kips)d : heeling distance

w = (- 0.94 x 3, 151.12)/(-0.94 – 27) = 106 kips 1,656 ft3

To correct the heel we need:

V3 = 1656 ft3

4.3 High Tide Scenario

4.3.1 Draft controlAt the highest tide, the water level is 1.26m below quay level, knowing the depth of the barge H, and the draft d1, we can obtain the excess height h1 as:

h1 = H – d1 – 1.26 = 4.88 – 1.03 – 1.26 = 2.59m

h1 = 2.59m

To align the deck elevation of the barge with the quay, we need to pump the barge a certain amount of water such that the draft of the barge will be:

d2 = d1 + h1 = 1.03 + 2.59 =3.62m

d2 =3.62m with the corresponding waterline length Lw12 = 72.10mwe can now obtain the volume displacement both at d1 and d2 drafts.This displacement at d1 is 1 =1,399.13m3

The displacement at d2 is 2 =5,255.82m3

The required volume of water to pump into the barge to achieve the draft d2 is obtained as:

V1 = 2 -1 =5,255.82 –1,399.13 =3,856.69m3

V1 = 3,856.69m3 =136,197.72ft3


4.3.2 Heel and Trim CorrectionThe correction of the trim and heel remains the same as in the case of low tide scenario.

Ballast Data Weight Calculations

Capacity% used

Weight

KG Wt*KG XCG (Ft)

YCG (Ft)

ZCG (Ft)

MY (Kip – Ft)

Mx (Kip –Fit)

Mz (Kip -Ft)

(Kips) % (Kip) (Ft) (Kip – Ft)

2610.00

9.10 23751.00

0.00 0.00 9.10 0.00 0.00 23751.00

0.00 0.00 0.00 0.00

0.00 0.00 0.00 0.00

0.00 0.00 0.00 0.00

0.00 0.00 0.00 0.00

0.00 0.00 0.00 0.00

0.00 0.00 -27483.30

0.00

501.52 18.00

9027.36

-54.80 -7.71 18.00

-3866.72

-2890.80

9027.36

39.60 18.00

712.80 -73.00 22.50 18.00

891.00 712.80

3151.12

10.63

33491.16

-9.64 -0.94 10.63

-2975.72

-30374.10

33491.16

655.36 2.50 16.38 0.20 3.28 80.00 28.00 0.20 458.64 1310.40

3.28

1638.40 27.50 451.10 2.20 992.42 8.00 0.00 2.20 0.00 3688.00

992.42

655.36 2.50 16.38 0.20 3.28 80.00 -28.00 0.20 -458.64 1310.40

3.28

655.36 2.50 16.38 0.20 3.28 40.00 28.00 0.20 458.64 655.20 3.28

1638.40 2.50 40.96 0.20 8.19 40.00 0.00 0.20 0.00 1638.40

8.19

655.36 2.50 16.38 0.20 3.28 40.00 -28.00 0.20 -458.64 655.20 3.28

655.36 16.20 106.30 1.30 138.19 0.00 28.00 1.30 2976.40

0.00 138.19

1638.40 18.20 299.00 1.46 436.54 0.00 0.00 1.46 0.00 0.00 436.54

655.36 2.50 16.38 1.20 3.28 0.00 -28.00 0.20 -458.64 0.00 3.28


655.36 2.50 16.38 0.20 3.28 -40.00 28.00 0.20 458.64 -655.20 3.28

1638.40 2.50 40.96 0.20 8.19 -40.00 0.00 0.20 0.00 -1638.40

8.19

655.36 2.50 16.38 0.20 3.28 -40.00 -28.00 0.20 -458.64 -655.20 3.28

655.36 2.50 16.38 0.20 3.28 -80.00 28.00 0.20 458.64 -1310.40

3.28

1638.40 2.50 40.96 0.20 8.19 -80.00 0.00 0.20 0.00 -3276.80

8.19

655.36 2.50 16.38 0.20 3.28 -80.00 0.00 0.20 0.00 1310.40

3.28

196.61 2.50 4.92 0.20 0.98 -110.00

28.00 0.20 137.76 -541.20 0.98

491.52 2.50 12.29 0.20 2.46 -110.00

0.00 0.20 0.00 -1351.90

2.46

196.61 2.50 4.92 0.20 0.98 -110.00

-28.00 0.20 -137.76 -541.20 0.98

Subtotal 1148.83

1.42 1625..64

26.44 25.59 1.42 2976.40

30376.90

1625.64

Total 4299.95

8.17 35116.80

0.00 0.00 8.17 0.68 2.80 35116.80

Inergy Jacket Barge 250’ x 72’ x 16’Tank Volume Perm. Ballast

Capacity Weight (Kips)

Number Ft3 %

1p 10240 100 655.361c 25600 100 1638.401s 10240 100 655.362p 10240 100 655.362c 25600 100 1638.402s 10240 100 655.363p 25600 100 655.363c 10240 100 1638.403s 25600 100 655.364p 10240 100 655.364c 25600 100 1638.404s 10240 100 655.365p 10240 100 655.365c 25600 100 1638.40


5s 10240 100 655.366p 3072 100 196.616c 7680 100 491.526s 3072 100 196.61

WECO Jacket Barge 250’ x 16’Loadout –Phase 0 (high Water

Ballasting Data Weight CalculationsCapacity

%Used Weight KG Wt*KG XCG (Ft)

YCG (Ft)

ZCG (Ft)

My (kip – Ft)

Mx (kip –Ft)

Mz (kip – Ft)

(Kips) % (Kips) (Ft) (Kips-f t)2610.00 9.10 23751.00 0.00 0.00 9.10 0.00 0.00 23751.00

0.00 0.00 0.00 0.000.00 0.00 0.00 0.000.00 0.00 0.00 0.000.00 0.00 0.00 0.000.00 0.00 0.00 0.000.00 0.00 0.00 0.00

501.52 18.00 9027.3 -54.80 -7.71 18.00-38666.72

-27483.30 9027.36

39.60 18.00 712.80 -73.00 22.50 18.00 891.0 -2890.80 712.80


3151.12 10.63 33491.16 -9.64 -0.94 10.63 -2975.72 -30374.10 33491.16655.36 2.50 16.38 0.20 3.28 80.00 28.00 0.20 458.64 1310.40 3.281638.40 85.00 1393.10 6.80 9473.08 80.00 0.00 6.80 0.00 111448.00 9473.08

655.36 2.50 16.38 0.20 3.28 80.00-28.00

0.20 -458.64 1310.40 3.28

655.36 70.00 458.75 5.60 2569.00 40.00 28.00 5.60 12845.00 18350.00 2569.001638.40 70.00 1146.88 5.60 6422.53 40.00 0.00 5.60 0.00 45875.20 6422.53

655.36 70.00 458.75 5.60 2569.00 40.00-28.00

5.60-12845.00

18350.00 2569.00

655.36 73.50 482.10 5.90 2844.39 0.00 28.00 5.90 13498.80 0.00 2844.391638.40 50.00 817.00 3.99 3259.83 0.00 0.00 3.99 0.00 0.00 3259.83

655.36 60.00 3.99 4.80 1882.56 0.00-28.00

4.80-10981.60

0.00 1882.56

655.36 70.00 4.80 5.60 2569.00 -40.00 28.00 5.60 12845.00 18350.00 2569.001638.40 70.00 5.60 5.60 64222.53 -40.00 0.00 5.60 0.00 -45875.20 6422.53

655.36 70.00 5.60 5.60 2569.00 -40.00-28.00

5.60-12845.00

-18350.00 2569.00

655.36 2.50 0.20 0.20 3.28 -80.00 28.00 0.20 458.64 1310.401638.40 60.00 4.80 4.80 4718.40 -80.00 0.00 4.80 0.00 -78640.00 4718.40655.36 2.50 0.20 0.20 3.28 -80.00 0.00 0.20 0.00 -1310.40 3.28

196.61 2.50 0.20 0.20 0.98-110.00

28.00 0.20 137.76 -541.20 0.98

491.52 2.50 0.20 0.20 2.46-110.00

0.00 0.20 0.00 -1351.90 2.46

196.61 2.50 0.20 0.20 0.98-110.00

-28.00

0.20 -137.76 -541.20 0. 98

Subtotal 8283.81 5.47 45316.85 3.67 0.36 5.47 2975.84 3037.70 445316.85Total 11434.93 6.89 78808.01 0.00 0.00 6.89 0.12 -0.40 78808.01

Tank Capacity

Tank Volume Perm.


Ballast CapacityWeight (Kips)

Number Ft3 %

1p 10240 100 655.361c 25600 100 1638.401s 10240 100 655.362p 10240 100 655.362c 25600 100 1638.402s 10240 100 655.363p 10240 100 655.363c 25600 100 1638.403s 10240 100 655.364p 10240 100 655.364c 25600 100 1638.404s 10240 100 655.365p 10240 100 655.365c 25600 100 1638.405s 10240 100 655.366p 3072 100 196.616c 7680 100 491.526s 3072 100 196.61


CAPACITY AND DIMENTIONS OF BALLAST TANKS

S/NO TANK FUNCTION LENGTH(ft)

LENGTH(m)

BREADTH(ft)

BREADTH(ft)

DEPTH(m)

CAPACITYVolume (ft3)

CAPACITYWeight ((kips)

1 1C Trim control (bow)

40.00 12.20 40.00 12.20 16.00 25600.00 1638.40

2 2P Draft control (tidal variation)

40.00 12.00 16.00 4.88 16.00 10240.00 1638.40

3 2C Draft control (tidal variation)

40.00 12.20 40.00 12.20 16.00 25600.00 655.36

4 2S Draft control (tidal variation )

40.00 12.20 16.00 4.88 16.00 10240.00 1638.40

5 3P Heel control (port)

40.00 12.20 16.00 4.88 16.00 10240.00 655.36

6 3C Draft control (primary)

40.00 12.20 40.00 12.20 16.00 25600.00 655.36

7 3S Heel control (starboard )

40.00 12.20 16.00 4.88 16.00 10240.00 1638.40

8 4P Draft control (tidal variation)

40.00 12.20 16.00 4.88 16.00 10240.00 655.36

9 4C Draft control (tidal variation

40.00 12.20 40.00 12.20 16.00 25600.00 1638.40

10 4S Draft control (tidal variation)

40.00 12.20 16.00 4.88 16.00 10240.00 655.36

11 5C Trim control (stern)

40.00 12.20 40.00 12.20 16.00 25600.00 1638.40

12 1P Unused tank 40.00 12.20 16.00 4.88 16.00 10240.00 655.3613 1S Unused tank 40.00 12.20 16.00 4.88 16.00 10240.00 655.36


14 5P Unused tank 40.00 12.20 16.00 4.88 16.00 10240.00 655.3615 5S Unused tank 40.00 12.20 16.00 4.88 16.00 10240.00 655.3616 6P Unused tank 25.00 7.62 16.00 4.88 - 3072.00 196.6117 6C Unused tank 25.00 7.62 40.00 12.20 - 7680.00 491.5218 6S Unused tank 25.00 7.62 16.00 12.20 - 30772.00 196.61

NOTE:Tank 3c is the primary draft control tank.Tanks 1c and 5c will be used for trim control.Tanks 3p and 3s will be used to heel angle correction.Tanks 2p,2c,2s,4p,4c and 4s will be used to control draft due to tidal variation.

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