MINIMUM ACCEPTABLE STABILITY - TM-55-1905-223-SDC0049

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WATERTIGHT INTEGRITY

TM-55-1905-223-SDC Shipboard Damage Control Manual for Landing Craft Utility (LCU) NSN 1905-01-154-1191

Basis of assignment

TM 55-1905-223-SDC

The order of procedure in this operation is to apply a transverse moment in the opposite direction to the

unsymmetrical load of EQUAL OR SMALLER magnitude. This may be done by:

a. Emptying a tank on the low side into the sea. The moment correction is the figure given on the

Liquid Loading Diagram (assuming the tank was completely full and is completely drained).

b. Shifting liquids from the low side to the high side. The transverse moment in this case is the sum

of the moment of the tank drained and the moment of the tank filled (assuming spaces are completely drained

and completely filled).

c. Jettisoning topside weights on the low side. The transverse moment correction is the weight in

tons multiplied by its original distance from the centerline of the ship in feet.

d. Shifting solid weights (cargo). The transverse moment is the weight in tons multiplied by the

transverse travel in feet.

CAUTION

Avoid shifting weight to a substantially higher level or flooding spaces above the

main deck. Excess weight high in the ship causes a rise in the center of gravity

and subsequent degradation of stability.

It is not always necessary to eliminate the list entirely. In some cases, total elimination of list may be

possible only by resorting to filling of tanks on the high side. The consequent increase in displacement would

probably offset any advantage to be gained from bringing the ship upright. If the ship is manageable, any

additional list correction should be undertaken only after due thought has been given to the problem.

5-33. MINIMUM ACCEPTABLE STABILITY. In order to resist the effects of damage, it is essential that the

vertical height of the ship's center of gravity (KG) be kept below a certain value. Calculations indicate that this

value is reached when carrying 350 tons of cargo. Therefore, the amount of cargo at departure should not

exceed this total.

5-34. LIMITING DRAFT.

a. Limiting value assigned. A limiting draft of 7.6 feet above the bottom of keel amidships and 7.74 feet

above the bottom of keel at the aft perpendicular (1087 tons of displacement) has been assigned to these

ships. Distinctive marks have been authorized to be painted on both sides of the ship, representing the above

drafts as guides against overloading.

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