Damage Assumptions
Clasification Society 2024 - Version 9.40
Statutory Documents - IMO Publications and Documents - Resolutions - Assembly - IMO Resolution A.320(IX) Regulation Equivalent to Regulation 27 of the International Convention on Load Lines,1966 (Adopted on 12 November 1975)Amended by Resolution A.514(13) - Annex - Regulation Equivalent to Regulation 27 of the International Convention on Load Lines, 1966 - Damage Assumptions

Damage Assumptions

  (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.


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