(12) The following principles
regarding the character of the assumed damage apply:
(a) The vertical extent of damage in all cases
is assumed to be from the base line upwards without limit.
(b) The transverse extent of damage is equal to
B/5 or 11.5 metres (37.7 feet), whichever is the lesser, measured
inboard from the side of the ship perpendicularly to the centre line
at the level of the summer load water-line.
(c) If damage of a lesser extent than specified
in sub-paragraphs (a) and (b) of this paragraph results in a more
severe condition, such lesser extent shall be assumed.
(d) Except where otherwise required by paragraph (10)(a) the flooding shall
be confined to a single compartment between adjacent transverse bulkheads
provided the inner longitudinal boundary of the compartment is not
in a position within the transverse extent of assumed damage. Transverse
boundary bulkheads of wing tanks, which do not extend over the full
breadth of the ship shall be assumed not to be damaged, provided they
extend beyond the transverse extent of assumed damage prescribed in
sub-paragraph (b) of this paragraph.
If in a transverse bulkhead there are steps or recesses
of not more than 3.05 metres (10 feet) in length located within the
transverse extent of assumed damage as defined in sub-paragraph (b)
of this paragraph, such transverse bulkhead may be considered intact
and the adjacent compartment may be floodable singly. If, however,
within the transverse extent of assumed damage there is a step or
recess of more than 3.05 metres (10 feet) in length in a transverse
bulkhead, the two compartments adjacent to this bulkhead shall be
considered as flooded. The step formed by the after peak bulkhead
and the after peak tank top shall not be regarded as a step for the
purpose of this Regulation.
(e) Where a main transverse bulkhead is located
within the transverse extent of assumed damage and is stepped in way
of a double bottom or side tank by more than 3.05 metres (10 feet),
the double bottom or side tanks adjacent to the stepped portion of
the main transverse bulkhead shall be considered as flooded simultaneously.
If this side tank has openings into one or several holds, such as
grain feeding holes, such hold or holds shall be considered as flooded
simultaneously. Similarly in a ship designed for the carriage of fluid
cargoes, if a side tank has openings into adjacent compartments, such
adjacent compartments shall be considered as empty and flooded simultaneously.
This provision is applicable even where such openings are fitted with
closing appliances, except in the case of sluice valves fitted in
bulkheads between tanks and where the valves are controlled from the
deck. Manhole covers with closely-spaced belts are considered equivalent
to the unpierced bulkhead except in the case of openings in topside
tanks making the topside tanks common to the holds.
(f) Where the flooding of any two adjacent fore
and aft compartments is envisaged main transverse watertight bulkheads
shall be spaced at least 1/3L2/3 or 14.5 metres (0.495L2/3 or 47.6 feet), whichever is the lesser, in order to be considered
effective. Where transverse bulkheads are spaced at a lesser distance,
one or more of these bulkheads shall be assumed as non-existent in
order to achieve the minimum spacing between bulkheads.