NEW CLASS B, C AND D AND EXISTING CLASS B SHIPS:

For the purpose of making damaged stability calculations the volume and surface permeabilities shall be as follows: Whichever results in more severe requirements. Spaces Permeability (%) Appropriated to cargo or stores 60 Occupied by accommodations 95 Occupied by machineries 85 Intended for liquids 0 or 95 Higher surface permeabilities are to be assumed in respect of spaces which, in the vicinity of the damaged waterplane, contain no substantial quantity of accommodation or machinery and spaces which are not generally occupied by any substantial quantity of cargo or stores. Assumed extent of damage shall be as follows: longitudinal extent: 3,0 metres plus 3 % of the length of the ship, or 11,0 metres or 10 % of the length of the ship, whichever is less; transverse extent (measured inboard from the ship's side, at right angles to the centreline at the level of the deepest subdivision load line): a distance of one fifth of the breadth of the ship; and vertical extent: from the base line upwards without limit; if any damage of lesser extent than that indicated in .4.1, .4.2 or .4.3 would result in a more severe condition regarding heel or loss of metacentric height, such damage shall be assumed in the calculations. Unsymmetrical flooding is to be kept to a minimum consistent with efficient arrangements. Where it is necessary to correct large angles of heel, the means adopted shall, where practicable, be self-acting, but in any case where controls to cross-flooding fittings are provided they shall be operable from above the bulkhead deck. For new class B, C and D ships the maximum angle of heel after flooding but before equalisation shall not exceed 15 °. Where cross-flooding fittings are required the time for equalisation shall not exceed 15 minutes. Suitable information concerning the use of cross-flooding fittings shall be supplied to the master of the ship. The final conditions of the ship after damage and, in the case of unsymmetrical flooding, after equalisation measures have been taken shall be as follows: in the case of symmetrical flooding there shall be a positive residual metacentric height of at least 50 mm as calculated by the constant displacement method; unless provided otherwise in paragraph .6.2b, in the case of unsymmetrical flooding the angle of heel for one-compartment flooding shall not exceed 7 ° for class B ships (new and existing) and 12 ° for classes C and D ships (new). For the simultaneous flooding of two adjacent compartments, a heel of 12 ° may be permitted for existing and new class B ships, provided that the factor of subdivision is nowhere greater than 0,50 in that part of the ship that is flooded; for existing class B non ro-ro passenger ships, constructed before 29 April 1990, in the case of unsymmetrical flooding, the angle shall not exceed 7 °, except that in exceptional cases the Administration may allow additional heel due to the unsymmetrical moment, but in no case shall the final heel exceed 15; in no case shall the margin line be submerged in the final stage of flooding. If it is considered that the margin line may become submerged during an intermediate stage of flooding, the Administration of the flag State may require such investigations and arrangements as it considers necessary for the safety of the ship. The master of the ship shall be supplied with the data necessary to maintain sufficient intact stability under service conditions to enable the ship to withstand the critical damage. In the case of ships requiring cross-flooding, the master of the ship shall be informed of the conditions of stability on which the calculations of heel are based and shall be warned that excessive heeling might result should the ship sustain damage when in a less favourable condition. The data referred to in paragraph .7 to enable the master to maintain sufficient intact stability shall include information which indicates the maximum permissible height of the ship's centre of gravity above keel (KG), or alternatively the minimum permissible metacentric height (GM), for a range of draughts or displacements sufficient to include all service conditions. The information shall show the influence of various trims taking into account the operational limits. Each ship shall have scales of draughts marked clearly at the bow and stern. In the case where the draught marks are not located where they are easily readable, or operational constraints for a particular trade make it difficult to read the draught marks, then the ship shall also be fitted with a reliable draught indicating system by which the bow and stern draughts can be determined. On completion of loading of the ship and prior to its departure, the master shall determine the ship's trim and stability and also ascertain and record that the ship is in compliance with stability criteria in the relevant regulations. The determination of the ship's stability shall always be made by calculation. An electronic loading and stability computer or equivalent means may be used for this purpose. No relaxation from the requirements for damage stability may be considered by the Administration of the flag State unless it is shown that the intact metacentric height in any service condition necessary to meet these requirements is excessive for the service intended. Relaxations from the requirements for damage stability shall be permitted only in exceptional cases and subject to the condition that the Administration of the flag State is to be satisfied that the proportions, arrangements and other characteristics of the ship are the most favourable to stability after damage which can practically and reasonably be adopted in the particular circumstances.

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Source: EUR-Lex (Cellar) · retrieved 2026-11-10 · Text as adopted (Official Journal); later amendments are not incorporated in this text.