2.1 A systematic investigation of damage survival
characteristics should be undertaken by making calculations to obtain
the minimum required GM or maximum allowable KG at a sufficient number
of draughts within the operating range to permit the construction
of a series of curves of “required GM" or “allowable KG"
in relation to draught and cargo tank content in way of the damage.
The curves must be sufficiently comprehensive to cover operational
trim requirements.
2.2 Each of the curves thus constructed relates
to one position of assumed damage only and the calculations should
be repeated for each damage and lesser extent of damage to be assumed
at any part of the ship.
2.3 Where it can be determined by inspection that
the effect of certain assumed damage will be less onerous than other
assumed damage, for which calculations are provided and curves prepared,
then the investigation of such damage cases may be dispensed with.
2.4 The damage calculations should take account
of:
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.1 tanks in way of the assumed damage filled with
liquid at increments of about 25% between empty and the maximim weight
of liquid, or liquids, intended to be carried in the particular tanks
under consideration;
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.2 the distribution of liquids in the adjacent
tanks concerned which will give the most severe result, taking into
account trim;
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.3 a number of draughts over the operating range,
up to and including the tropical freeboard mark. The fresh water freeboards
need not be considered;
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.4 the effect of damage involving the machinery
space and adjacent tanks containing liquids over a number of draughts
as in 2.4.3;
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.5 the ship in either the departure or the arrival
condition, whichever will give the most severe result;
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.6 the ship without trim and a sufficient number
of trims covering the operating range, in order to permit interpolation.