Regulation 5 - Subdivision and Damage Stability
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Statutory Documents - IMO Publications and Documents - Resolutions - Assembly - IMO Resolution A.265(VIII) – Regulations on Subdivision and Stability of Passenger Ships as an Equivalent to Part B of Chapter II of the International Convention for the Safety of Life at Sea, 1960 – (Adopted on 20 November 1973) - Annex - Regulations on Subdivision and Stability of Passenger Ships as An Equivalent to Part B of Chapter II of the International Convention for the Safety of Life at Sea, 1960 - Regulation 5 - Subdivision and Damage Stability

Regulation 5 - Subdivision and Damage Stability

  (a) Sufficient intact stability shall be provided in all service conditions so as to enable the ship to comply with the provisions of this Regulation. Before certification of the ship the Administration shall be satisfied that the required intact stability can practicably be obtained in service.

  (b)

  • (i) All ships shall be so designed as to comply with the provisions of this Regulation in the event of flooding due to one side damage with a penetration of 0.2B1 from the ship's side at right angles to the centreline at the he level of the subdivision loadline and a longitudinal extent of 9.8 feet (3.00 metres)+0.03Ls , or 36 feet (11 metres) whichever is the less, occurring anywhere in the ship's length, but not including a transverse bulkhead. However, where a bulkhead is stepped it shall be assumed as subject to damage.

  • (ii) Ships for which N is more than 600 shall additionally be able to comply with this Regulation in the event of flooding, due to side damage including transverse bulkheads occurring anywhere within a length equal to , measured from the forward terminal of Ls , where N is as defined in Regulation 2(c) and (d). The value of shall not be more than one.

  • (iii) In any calculation required under this paragraph the damage shall be assumed to extend from the base line upwards without limit. However, if flooding due to a lesser extent of damage either vertically, transversely or longitudinally results in a higher necessary intact metacentric height, such a lesser extent of damage shall be assumed. In all cases, however, only one breach in the hull and only one free surface need be assumed. For the purpose of assessing heel prior to equalization the bulkheads and deck bounding refrigerated spaces and other decks or inner divisions which in the opinion of the Administration are likely to remain sufficiently watertight after damage, shall be regarded as limiting flooding. Otherwise, flooding shall be assumed as limited only by undamaged watertight structural divisions.

  (c)

  • (i) In the final stage of flooding:

    • (1) there shall be a positive metacentric height, GM, calculated by the constant displacement method and for the ship in upright condition, of at least

    Where:
    Δ = displacement of the ship in the undamaged condition (in long tons or metric tons respectively);

    • (2) the angle of heel in the case of one compartment flooding shall not exceed 7 degrees. For the simultaneous flooding of two or more adjacent compartments a heel of 12 degrees may be permitted unless the Administration considers a lesser heel necessary to ensure an adequate amount and range of residual stability;

    • (3) except in way of the flooded compartment or compartments no part of the relevant bulkhead deck at side shall be immersed.

  • (ii) Unsymmetrical flooding shall be kept to a minimum consistent with efficient arrangements. If any equalizing arrangements are necessary to ensure that the angle of heel in the final stage of flooding does not exceed the limits specified in sub-paragraphs (i)(2) and (3) of this paragraph, these arrangements shall, where practicable, be self-acting. However, if controls are necessary, they shall be operable from above the highest relevant bulkhead deck. All such arrangements shall be acceptable to the Administration.

  • (iii) The Administration shall be satisfied that stability prior to equalization is sufficient. However, in no case shall the maximum heel before equalization exceed 20 degrees nor shall it result in progressive flooding. Additionally, the time for equalization of cross-connected spaces to at least the limits specified in sub-paragraphs (i)(2) and (3) of this paragraph shall not exceed ten minutes.

  • (iv) The Administration shall be satisfied that the residual stability is sufficient during intermediate flooding and that progressive flooding will not take place. Calculations relative thereto shall be in accordance with the provisions of sub-paragraph (b)(iii) of this Regulation, respecting the assumed extent of damage and resulting extent of flooding. Heel during intermediate flooding due either to negative metacentric height alone or in combination with unsymmetrical flooding shall not exceed 20 degrees.

  (d) Damage stability calculations performed in compliance with this Regulation shall be such as to take account of the form and the design characteristics of the ship and the arrangements, configuration and probable contents of the compartments considered to be flooded. In making calculations for heel prior to equalization and for equalization time, the flooding of that portion of the ship opened to the sea shall be assumed to be completed prior to commencement of equalization. For each initial draught condition the ship shall be at the most unfavourable intact service trim anticipated at that draught having regard to the influence of the trim on the freeboard in the flooded condition.

  (e) The intact metacentric height, and corresponding vertical centre of gravity, necessary to provide compliance with the requirements specified in paragraphs (b) and (c) of this Regulation shall be determined for the operating range of draughts between ds and do . If (ds - do ) does not exceed 0.1 ds , damage stability calculations may be made only for ds and do, and the intermediate values may be obtained by linear interpolation. If (ds - do ) exceeds 0.1 ds , damage stability calculations shall also be made for at least one additional intermediate draught. However, in all cases where there are vertical discontinuities in permeabilities or in free surfaces which may result in discontinuities in the necessary intact metacentric height, damage stability calculations shall be made for the corresponding draughts in order to define such discontinuities.

Parent topic: Annex - Regulations on Subdivision and Stability of Passenger Ships as An Equivalent to Part B of Chapter II of the International Convention for the Safety of Life at Sea, 1960
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