Buoy_Barge_Stability_Addendum_B.pdf

Buoy Barge Stability Analysis Related to Crane Upgrade

Estimation of lightship displacement:

A modified deadweight survey was performed during the ship check visit on 14 October, 2010 to determine light ship displacement. This involved measuring barge freeboard, sounding ballast tanks, and documenting weights and locations of existing deck cargo. The remainder of the barge contents were considered to be part of the light ship condition. The barge crane was in the stowed condition at this time.

Freeboard was measured at locations 6 ft. and 146 ft. from Frame 0 (P/S). Frame 0, centerline, on the baseline is the reference point for all dimensions.

A model of the barge hull was constructed to allow hydrostatic analysis using GHS software.

The following lists the freeboard measurements, calculated drafts, and calculated displacement in the as-surveyed condition.

SLSDC Buoy Barge Freeboard Measurements 10/14/2010

Forward, 4'-0" FWD of FR#1 Port 83" STBD 83" Aft; 6'-0" FWD of FR#15 Port 89.5" STBD 89.5"

Calculated Draft (ft.) PORT STBD FWD 3.14 3.14 at X=6.0 ft.

AFT 2.59 2.59 at X=144 ft.

Specific Gravity measures at 1.000 Water Temp: 58 Deg. F

Deck Plating: 25.5# PL =5/8” Side Plating 17.85# = 7/16" Bottom Plating 15.3# = 3/8"

Ballast Tanks FR 10-12 P/S Filled to 35" below molded deck line.

Hydrostatic properties for the barge at this draft, calculated using GHS software, are as follows:

01/06/11 11:59:44 Marine Systems Corporation

GHS 12.00 SLSDC BUOY BARGE DISPLACEMENT ON 14OCT2010 BUOYBARG

WEIGHT and DISPLACEMENT STATUS Baseline draft: 3.164 @ Origin

Trim: Fwd 0.23 deg., Heel: zero Part------------------------------Weight(LT)----LCG-----TCG-----VCG

WEIGHT 682.62 0.00 0.00 0.00

SpGr------Displ(LT)----LCB-----TCB-----VCB------RefHt HULL 1.000 682.62 76.04a 0.05p 1.43 -3.16

Righting Arms: 76.03a -0.05s Distances in FEET.------------------------------------------------------------

HYDROSTATIC PROPERTIES

Trim: Fwd 0.23 deg., No Heel

Origin Displacement Center of Buoyancy Depth----Weight(LT)----LCB-----TCB-----VCB-----WPA-----LCF------BML-----BMT

3.164 682.62 76.04a 0.05p 1.43 8699 76.73a 621.3 107.44

Distances in FEET.-------Specific Gravity = 1.000.--------------------------

CURVES OF FORM

HULL.C Component of Part HULL

Trim: Fwd 0.23 deg. Heel: zero Ref Pt Volume Block Displ/ WaterPl MaxSect PrismaticCoefs Depth-----(Cu Ft)----Coef---Length----Coef----Coef----Long----Vert

0.00 0.000

0.50 1856 0.500 27.2 1.000 1.000 0.500 0.500

1.00 6064 0.713 60.0 0.994 1.000 0.713 0.717

1.50 10325 0.803 100.6 0.994 1.000 0.803 0.808

2.00 14609 0.847 140.0 0.994 1.000 0.847 0.852

2.50 18916 0.872 178.4 0.994 1.000 0.872 0.878

3.00 23247 0.888 215.8 0.994 1.000 0.888 0.894

3.50 27600 0.899 252.2 0.994 1.000 0.899 0.905

4.00 31977 0.907 287.6 0.994 1.000 0.907 0.912

4.50 36377 0.912 322.1 0.994 1.000 0.912 0.917

5.00 40799 0.915 355.7 0.994 1.000 0.915 0.921

5.50 45245 0.918 388.3 0.994 1.000 0.918 0.924

6.00 49714 0.920 420.6 0.994 1.000 0.920 0.926

6.50 54194 0.926 458.5 0.994 1.000 0.926 0.931

7.00 58673 0.931 496.3 0.994 1.000 0.931 0.936

7.50 63152 0.935 534.2 0.994 1.000 0.935 0.941

8.00 67631 0.939 572.1 0.994 1.000 0.939 0.944

Distances in FEET.---Length is true waterline.----------------------- HULL Reference Point: Long.= 0.00 Trans.= 0.00 Vert.= 0.00

C U R V E S o f

F O R M a t d e g r e e s

H U L L

C o m p o n e n t o f

P a r t

H U L L

Depth in FEET

C o e f f i c i e n t

S c a l e

G e n e r a l

S c a l e

V o l u m e

C U F T

B l o c k

C o e f

D i s p l L e n g t h

R a t i o

W a t e r p l a n e

C o e f

M a x i m u m

S e c t i o n

C o e f

L o n g

P r i s m a t i c

V e r t i c a l

P r i s m a t i c

D e p t h i s r e l a t i v e t o

H U L L

R e f e r e n c e

P o i n t

HULL Isometric Projection and Body Plan

Using these values, a light ship condition is calculated by deducting the ballast and deck cargo.

In this instance, the weight of the crane is deducted as well since the light ship condition will be used to evaluate the effects of installing a crane with different characteristics.

Mom. Arm (Ft.) Moments (Ft-LT)

Deck Cargo X Y Z X-

Mom Y-

Mom Z-

Mom Unit Wt.(lb) Qty Tot. Wght.

Sinkers 5,600 4 22,400 143.7 0 11 1,437 0 110 1-1/4" Chain (Shots) 1,200 7 8,400 5 -12 11 19 -45 41 1-1/4" Chain (Shots) 1,200 2 2,400 5 12 11 5 13 12 Navy Anchor 2,993 1 2,993 5.5 24 11 7 32 15

Total Deck Weights 36,193 90.9 0.0 11.0 1,468 0 178

Ballast Unit Wt.(lb) Qty Tot. Wght.

BALLAST1.S (FW) 147,513 0.000 0 60 24 0.00 0 0 0

BALLAST2.P (FW) 147,513 0.000 0 60 -24 0.00 0 0 0

BALLAST3.S (FW) 147,513 0.708 104,488 110 24 3.54 5,131 1,120 165

BALLAST4.P (FW) 147,513 0.708 104,488 110 -24 3.54 5,131 -1,120 165

Total Ballast 208,977 110.0 0.0 3.54 10,262 0 330

Crane estimates Unit Wt.(lb) Qty Tot. Wght.

Crane weight listed at 56,000 lb. 56,000 1 56,000 63 0 22 1,575 0 550 Hydraulic Oil Capacity 300 gal. 2316 75 0 21 78 0 22 Fuel Tank Capacity 140 gal. 991 75 0 21 33 0 9

Total crane w/fluids 59,307 63.7 0.0 21.9 1,686 0 581

Summary - All Weights (Lbs) Tot. Wght. X Y Z X-

Mom Y-

Mom Z-

Mom Deck Cargo 36,193 90.9 0.0 11.0 1,468 0 178 Ballast 208,977 110.0 0.0 3.5 10,262 0 330 Crane 59,307 63.7 0.0 21.9 1,686 0 581

Calculated Hull, Deckhouse & Hull Eqpmt 1,224,592 70.4 0.0 7.0 38490 0 3827

As Surveyed (check) 1,529,069 76.04 0.00 7.20 51,906 0 4,916

As Surveyed (Long Tons) 682.62 76.04 0.00 7.20

Table 1: Calculation of Light Ship Condition

In order to estimate the heeling effect of installing a crane with longer reach, a value of

7.0 ft above baseline is assumed for the barge hull and deckhouse.

The loading characteristics of a potential replacement for the existing crane were evaluated using the stated requirement of similar load capability to the existing crane but at a maximum reach of 90 ft.

The “Existing Crane” limits shown in the following table are taken from the Capacity Chart (Table 1-1 of the Alaska Marine Crane O&M Manual). The “Reach” for the replacement crane is calculated based on the same percentage of maximum reach as for the existing crane. For example, in the first case, 55 ft. / 77 ft. = 71.4%. for the replacement crane, 90 ft. x 71.4% = 64 ft. Worst case loading is identified where the moment is maximum.

Existing Crane Potential

Replacement

Elev.

(Deg.)

Reach (Ft.)

Load (lbs)

Moment (lb-ft)

% of Full

Reach Reach (Ft.)

Load (lbs)

Moment (lb-ft)

0 55 20,000 1,100,000 71.4% 64 20,000 1,285,714 15 54 27,200 1,468,800 70.1% 63 27,200 1,716,779 30 48 33,400 1,603,200 62.3% 56 33,400 1,873,870 45 40 39,900 1,596,000 51.9% 47 39,900 1,865,455 60 30 54,500 1,635,000 39.0% 35 54,500 1,911,039 75 16 90,000 1,440,000 20.8% 19 90,000 1,683,117 80 11 110,500 1,215,500 14.3% 13 110,500 1,420,714 0 77 6,000 462,000 100.0% 90 6,000 540,000 15 75 6,600 495,000 97.4% 88 6,600 578,571 30 68 7,400 503,200 88.3% 79 7,400 588,156 45 56 8,900 498,400 72.7% 65 8,900 582,545 60 41 11,100 455,100 53.2% 48 11,100 531,935 75 22 14,900 327,800 28.6% 26 14,900 383,143 80 16 21,000 336,000 20.8% 19 21,000 392,727

Table 2: Estimation of max. moment for a replacement crane

The load and boom reach for the case with the highest moment (54,500 lb. load at 35 ft.

radius) , in conjunction with weight and center of gravity data for a potential replacement crane have been applied to the barge hydrostatic model. The candidate replacement that we were able to get weight data for is the Mantis 14010 pedestal crane. This crane features two counterweights totaling 30,000 lb.

The stability data and curves for the barge with this hook loading and with deck loading as observed on the December buoy run are shown in the tables and charts that follow. A summary of the deck cargo load is shown in the table 3.

Mom. Arm (Ft.) Moments (Ft-LT)

Deck Cargo 12/14/2010 X Y Z X-

Mom Y-

Mom Z-

Mom

Unit

Wt.(LT) Qty Tot.

Wght.

Sinkers & Chain 47,040 1 47,040 145 12 3,045 0 252 Winter Marks & Sink 22,400 1 22,400 66 12.5 660 0 125 Buoy 6,720 1 6,720 58 14 174 0 42 Buoys 100,800 1 100,800 20 14 900 0 630 Test Weight Sinker 6,500 1 6,500 100 11.25 33 Chain & Bridles 15,680 1 15,680 5 11.25 35 0 79 Total Deck Weights 199,140 54.1 -0.4 13.1 4,814 0 1,160

Table 3: Deck cargo load for December 2010 buoy run

The conditions modeled are for the boom at 0o and 90o with the elevation and hook load for maximum moment, and with aft ballast tanks empty to full. Heel and trim angles for these cases are within working limits.

01/06/11 15:20:06 Marine Systems Corporation

GHS 12.00 SLSDC BUOY BARGE WITH NEW COUNTERWEIGHTED CRANE BUOYBARG

Boom at 0 Deg. train and 60 Deg. elevation; Load = 54,500 lb.

WEIGHT STATUS

Trim: Fwd 0.65 deg., Heel: 0.00 deg.

Part------------------------------Weight(LT)----LCG-----TCG-----VCG LIGHT SHIP 546.69 70.40a 0.00 7.00 Deck Load 88.90 54.10a 0.40p 13.10 New Crane & Hook Load 57.92 55.40a 0.00 55.30

Total Fixed---------> 693.51 67.06a 0.05p 11.82 Load-----SpGr-----Weight(LT)----LCG-----TCG-----VCG-------FSM

BALLAST3.S 0.708 1.000 46.65 109.95a 24.00s 3.54 79.1 BALLAST4.P 0.708 1.000 46.65 109.95a 24.00p 3.54 79.1

Total Tanks---------> 93.29 109.95a 0.00 3.54 158.1 Total Weight--------> 786.80 72.14a 0.05p 10.83

Free Surface Adjustment----------> 0.20 Adjusted CG----------------------> 72.14a 0.05p 11.04

Distances in FEET.-------------------------------------------Moments in Ft-LT.

RIGHTING ARMS vs HEEL ANGLE Fixed CG: LCG = 67.06a TCG = 0.05p VCG = 11.82

Origin Degrees of Displacement Righting Arms Freebd Depth---Trim----Heel----Weight(LT)---in Trim--in Heel---> Area--(Extra)

4.155 0.65f 0.00 786.81 0.00 0.000 0.00

4.089 0.62f 5.00s 786.79 0.00 7.419 18.55 3.31

3.889 0.71f 10.00s 786.63 0.00 12.868 70.09 0.80

3.670 0.76f 11.87s 786.80 0.00 13.880 95.15 -0.00

3.212 0.85f 15.00s 786.79 0.00 14.897 140.54 -1.27

2.681 1.04f 18.75s 786.80 0.00 15.252 197.49 -2.81

2.503 1.10f 20.00s 786.81 0.00 15.226 216.53 -3.32

1.774 1.35f 25.00s 786.80 0.00 14.703 291.35 -5.34

1.038 1.59f 30.00s 786.80 0.00 13.768 362.70 -7.33

0.309 1.83f 35.00s 786.79 0.00 12.588 428.70 -9.28

-0.403 2.06f 40.00s 786.79 0.00 11.237 488.33 -11.18 -1.098 2.30f 45.00s 786.79 0.00 9.756 540.87 -13.01 -1.774 2.52f 50.00s 786.80 0.00 8.173 585.73 -14.74 -2.430 2.73f 55.00s 786.80 0.00 6.510 622.47 -16.38 -3.067 2.91f 60.00s 786.81 0.00 4.787 650.74 -17.88 Distances in FEET.------Specific Gravity = 1.000.---------Area in Ft-Deg.

Note: The Center of Gravity shown above is for the Fixed Weight of

693.51 LT. As the tank load centers shift with heel and

trim, the total Center of Gravity varies. The righting arms shown above include the effect of the C.G. variation.

01/06/11 15:20:06 Marine Systems Corporation

0 5 10 15 20 25 30 35 40 45 50 55 60

Degrees of Heel --> Starboard

F T

GM = 84.68

Righting Arm

Dk/MargImm.

F T D e g

0 5 10 15 20 25 30 35 40 45 50 55 60

Righting Area

01/06/11 16:14:26 Marine Systems Corporation

Boom at 90 Deg. train and 60 Deg. elevation; Load = 54,500 lb.

WEIGHT STATUS

Trim: Fwd 0.54 deg., Heel: Stbd 0.71 deg.

Part------------------------------Weight(LT)----LCG-----TCG-----VCG LIGHT SHIP 546.69 70.40a 0.00 7.00 Deck Load 88.90 54.10a 0.40p 13.10 New Crane & Hook Load 57.92 69.90a 14.40s 55.30

Total Fixed---------> 693.51 68.27a 1.15s 11.82 Load-----SpGr-----Weight(LT)----LCG-----TCG-----VCG-------FSM

BALLAST3.S 0.708 1.000 46.65 109.96a 24.02s 3.54 79.1 BALLAST4.P 0.708 1.000 46.65 109.96a 23.98p 3.54 79.1

Total Tanks---------> 93.29 109.96a 0.02s 3.54 158.2 Total Weight--------> 786.80 73.21a 1.02s 10.83

Free Surface Adjustment----------> 0.20 Adjusted CG----------------------> 73.21a 1.01s 11.04

Distances in FEET.-------------------------------------------Moments in Ft-LT.

RIGHTING ARMS vs HEEL ANGLE Fixed CG: LCG = 68.27a TCG = 1.15s VCG = 11.82

Origin Degrees of Displacement Righting Arms Freebd Depth---Trim----Heel----Weight(LT)---in Trim--in Heel---> Area--(Extra)

4.004 0.54f 0.71s 786.81 0.00 0.000 0.00 5.67

3.922 0.50f 5.71s 786.77 0.00 7.408 18.52 3.09

3.624 0.58f 10.71s 786.68 0.00 12.279 68.80 0.68

3.397 0.61f 12.36s 786.80 0.00 13.081 89.70 -0.00

2.860 0.70f 15.71s 786.79 0.00 14.051 135.52 -1.31

2.326 0.83f 19.12s 786.80 0.00 14.297 184.08 -2.65

2.071 0.89f 20.71s 786.81 0.00 14.243 206.83 -3.28

1.258 1.08f 25.71s 786.80 0.00 13.679 276.64 -5.22

0.439 1.25f 30.71s 786.80 0.00 12.746 342.86 -7.12

-0.369 1.43f 35.71s 786.79 0.00 11.589 403.78 -8.98 -1.162 1.61f 40.71s 786.79 0.00 10.273 458.50 -10.79 -1.938 1.78f 45.71s 786.79 0.00 8.838 506.33 -12.52 -2.691 1.94f 50.71s 786.80 0.00 7.309 546.74 -14.16 -3.422 2.08f 55.71s 786.79 0.00 5.707 579.31 -15.70 -4.130 2.21f 60.71s 786.80 0.00 4.050 603.72 -17.12 Distances in FEET.------Specific Gravity = 1.000.---------Area in Ft-Deg.

Note: The Center of Gravity shown above is for the Fixed Weight of

693.51 LT. As the tank load centers shift with heel and

01/06/11 16:14:26 Marine Systems Corporation

0 5 10 15 20 25 30 35 40 45 50 55 60

Degrees of Heel --> Starboard

F T

GM = 84.64

Righting Arm

Dk/MargImm.

F T D e g

01/06/11 16:16:17 Marine Systems Corporation

Boom at 90 Deg. train and 60 Deg. elevation; Load = 54,500 lb.

Ballast Tanks Empty

WEIGHT STATUS

Trim: Fwd 0.96 deg., Heel: Stbd 0.71 deg.

Part------------------------------Weight(LT)----LCG-----TCG-----VCG-------FSM LIGHT SHIP 546.69 70.40a 0.00 7.00 Deck Load 88.90 54.10a 0.40p 13.10 New Crane & Hook Load 57.92 69.90a 14.40s 55.30

Total Weight--------> 693.51 68.27a 1.15s 11.82 Load-----SpGr-----Weight(LT)----LCG-----TCG-----VCG

Total Tanks---------> 0.00 0.0 Distances in FEET.-------------------------------------------Moments in Ft-LT.

RIGHTING ARMS vs HEEL ANGLE LCG = 68.27a TCG = 1.15s VCG = 11.82

Origin Degrees of Displacement Righting Arms Freebd Depth---Trim----Heel----Weight(LT)---in Trim--in Heel---> Area--(Extra)

4.183 0.96f 0.71s 693.52 0.00 0.000 0.00 5.50

4.137 0.97f 5.71s 693.51 0.00 8.194 20.48 2.88

3.922 1.22f 10.71s 693.50 0.00 12.702 74.69 0.38

3.818 1.26f 11.59s 693.50 0.00 13.114 86.07 0.00

3.219 1.46f 15.71s 693.47 0.00 14.239 143.05 -1.67

2.723 1.68f 19.01s 693.51 0.00 14.447 190.42 -2.99

2.472 1.80f 20.71s 693.43 0.00 14.393 214.90 -3.68

1.757 2.18f 25.71s 693.51 0.00 13.814 285.67 -5.72

1.053 2.58f 30.71s 693.52 0.00 12.832 352.46 -7.73

0.366 2.97f 35.71s 693.53 0.00 11.605 413.65 -9.72

-0.302 3.35f 40.71s 693.52 0.00 10.209 468.25 -11.64 -0.949 3.72f 45.71s 693.52 0.00 8.690 515.55 -13.50 -1.577 4.07f 50.71s 693.52 0.00 7.077 555.01 -15.27 -2.186 4.39f 55.71s 693.52 0.00 5.393 586.21 -16.93 -2.779 4.68f 60.71s 693.52 0.00 3.659 608.86 -18.46 Distances in FEET.------Specific Gravity = 1.000.---------Area in Ft-Deg.

01/06/11 16:16:17 Marine Systems Corporation

0 5 10 15 20 25 30 35 40 45 50 55 60

Degrees of Heel --> Starboard

F T

GM = 96.59

Righting Arm

Dk/MargImm.

F T D e g

01/06/11 16:17:11 Marine Systems Corporation

Boom at 90 Deg. train and 60 Deg. elevation; Load = 54,500 lb.

Aft Ballast Tanks Full

WEIGHT STATUS

Trim: Fwd 0.36 deg., Heel: Stbd 0.72 deg.

Part------------------------------Weight(LT)----LCG-----TCG-----VCG LIGHT SHIP 546.69 70.40a 0.00 7.00 Deck Load 88.90 54.10a 0.40p 13.10 New Crane & Hook Load 57.92 69.90a 14.40s 55.30

Total Fixed---------> 693.51 68.27a 1.15s 11.82 Load-----SpGr-----Weight(LT)----LCG-----TCG-----VCG-------FSM

BALLAST3.S 1.000 1.000 65.88 110.00a 24.00s 5.00 0.0 BALLAST4.P 1.000 1.000 65.88 110.00a 24.00p 5.00 0.0

Total Tanks---------> 131.77 110.00a 0.00 5.00 0.0 Total Weight--------> 825.28 74.93a 0.97s 10.73

Free Surface Adjustment----------> 0.00 Adjusted CG----------------------> 74.93a 0.97s 10.73

Distances in FEET.-------------------------------------------Moments in Ft-LT.

RIGHTING ARMS vs HEEL ANGLE Fixed CG: LCG = 68.27a TCG = 1.15s VCG = 11.82

Origin Degrees of Displacement Righting Arms Freebd Depth---Trim----Heel----Weight(LT)---in Trim--in Heel---> Area--(Extra)

3.929 0.36f 0.72s 825.27 0.00 0.000 0.00 5.75

3.846 0.32f 5.72s 825.28 0.00 7.060 17.65 3.17

3.517 0.34f 10.72s 825.27 0.00 12.061 66.31 0.78

3.232 0.35f 12.66s 825.28 0.00 13.031 90.83 -0.00

2.727 0.40f 15.72s 825.28 0.00 13.925 132.24 -1.18

2.169 0.47f 19.08s 825.28 0.00 14.159 179.77 -2.48

1.893 0.51f 20.72s 825.28 0.00 14.103 202.89 -3.10

1.036 0.61f 25.72s 825.28 0.00 13.551 272.03 -5.00

0.172 0.70f 30.72s 825.28 0.00 12.645 337.66 -6.85

-0.688 0.79f 35.72s 825.28 0.00 11.520 398.17 -8.66 -1.538 0.87f 40.72s 825.28 0.00 10.240 452.63 -10.41 -2.372 0.95f 45.72s 825.28 0.00 8.842 500.38 -12.09 -3.186 1.03f 50.72s 825.28 0.00 7.350 540.90 -13.67 -3.976 1.09f 55.72s 825.28 0.00 5.786 573.77 -15.15 -4.739 1.15f 60.72s 825.28 0.00 4.165 598.67 -16.51 Distances in FEET.------Specific Gravity = 1.000.---------Area in Ft-Deg.

Note: The Center of Gravity shown above is for the Fixed Weight of

693.51 LT. As the tank load centers shift with heel and

01/06/11 16:17:11 Marine Systems Corporation

0 5 10 15 20 25 30 35 40 45 50 55 60

Degrees of Heel --> Starboard

F T

GM = 80.57

Righting Arm

Dk/MargImm.

F T D e g

Stability Standards

Lifting Vessels. The requirements of 46CFR173, Sub Part B “Stability Requirements for Lifting Vessels” were reviewed for applicability. This Sub Part B applies for vessels with a maximum heeling moment with respect to lift capability exceeding (0.67)(W)(GM)(F/B) in meter-metric tons or foot-long tons, where:

W=displacement of the vessel with the hook load included in metric (long) tons.

GM=metacentric height with hook load included in meters (feet).

F=freeboard to the deck edge amidships in meters (feet).

B=beam in meters (feet).

For the buoy barge in the loading condition observed in December 2010;

(0.67)(756.34 LT)(84.83 ft)(5.38 / 60) = 3855 Ft-LT

The maximum heeling moment identified for this barge due to crane lift is (35 ft.)( 54,550/2240 LT) = 852 Ft-LT. (much less than 3855 Ft-LT). Sub Part B therefore does not apply.

Deck Barges. The stability requirements for deck barges are in 46CFR174 and are as follows:

174.015 Intact stability.

(a) Except as provided in §174.020, in each condition of loading and operation, each barge must be shown by design calculations to have an area under the righting arm curve up to the angle of maximum righting arm, the downflooding angle, or 40 degrees, whichever angle is smallest, equal to or greater than—

(1) 15 foot-degrees (4.57 meter-degrees) for ocean and Great Lakes winter service; and

(2) 10 foot-degrees (3.05 meter-degrees) for lakes, bays, sounds, and Great Lakes summer service.

(b) For the purpose of this section, downflooding angle means the static angle from the intersection of the vessel's centerline and waterline in calm water to the first opening that does not close watertight automatically.

From the stability curves calculated for maximum lift moment with the deck load condition as seen on the December buoy run, 15 foot-degrees area under the righting arm curve is attained at a heel angle well below the limits listed above. Therefore the barge will be well within stability standards with a replacement crane and with an extended reach of 90 ft.