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(c) For the purpose of making damage stability calculations the volume and surface permeabilities shall be as follows : Spaces. Permeability. Occupied by cargo, coal or stores .. 60 Occupied by accommodations .. .. .. 95 Occupied by machinery .. .. 85 Intended for liquids .. .. .. oor 95* * Whichever results in the more severe requirements. (id) Minimum assumed extent of damage shall be as follows : (i) Longitudinal extent: 10 feet (or 3-05 metres) plus 3 per cent, of the length of the ship, or 35 feet (or 10-67 metres) whichever is the less. (ii) Transverse extent (measured inboard from the ship's side, at right angles to the centre line at the level of the deepest subdivision load line) : a distance of one-fifth of the breadth of the ship, as defined in Regulation 2. (iii) Vertical extent: From top of double bottom up to the margin line. (iv) If any damage of lesser extent than that indicated in the foregoing subparagraphs (i), (ii) and (iii), would result in a more severe condition regarding heel or loss of metacentric height such damage shall be assumed in the calculations. (e) Unsymmetrical flooding is to be kept to a minimum consistent with efficient arrangements. Where special cross-flooding fittings are provided these, together with the maximum heel before equalization, shall be acceptable to the Administration. Suitable information concerning the use of such fittings shall be supplied to the master of the ship. (/) The final conditions of the ship after damage and after equalization measures have been taken shall be as follows : (i) In the case of symmetrical flooding the residual metacentric height shall be positive, except that, in special cases, the Administration may accept a negative metacentric height (upright) provided the resulting heel is not more than seven degrees. (ii) In the case of unsymmetrical flooding the total heel shall not exceed seven degrees, except that, in special cases, the Administration may allow additional heel due to the unsymmetrical moment, but in no case shall the final heel exceed fifteen degrees. (iii) 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 may require such investigations and arrangements as it shall consider necessary for the safety of the ship. (g) 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

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33