Merchant Shipping Act, 1951 (Act No. 57 of 1951)SchedulesSecond ScheduleProtocol of 1978 Relating to the International Convention for the Safety of Life at Sea, 1974AnnexChapter II–1 : Construction — Subdivision and Stability, Machinery and Electrical InstallationsPart B — Subdivision and StabilityRegulation 4 : Permeability |
| (a) | The definite assumptions referred to in Regulation 3 of this Chapter relate to the permeabilities of the spaces below the margin line. |
In determining the floodable length, a uniform average permeability shall be used throughout the whole length of each of the following portions of the ship below the margin line:
(i) The machinery space as defined in Regulation 2 of this Chapter;
(ii) the portion forward of the machinery space; and
(iii) the portion abaft the machinery space.
(b)
| (i) | The uniform average permeability throughout the machinery space shall be determined from the formula: |
where—
| a = | volume of the passenger spaces, as defined in Regulation 2 of this Chapter, which are situated below the margin line within the limits of the machinery space; |
| c = | volume of between deck spaces below the margin line within the limits of the machinery space which are appropriated to cargo, coal or stores; |
| v = | whole volume of the machinery space below the margin line. |
| (ii) | Where it is shown to the satisfaction of the Administration that the average permeability as determined by detailed calculation is less than that given by the formula, the detailed calculated value may be used. For the purpose of such calculation, the permeabilities of passenger spaces, as defined in Regulation 2 of this Chapter, shall be taken as 95, that of all cargo, coal and store spaces as 60, and that of double bottom, oil fuel and other tanks at such values as may be approved in each case. |
| (c) | Except as provided in paragraph (d) of this Regulation, the uniform average permeability throughout the portion of the ship before (or abaft) the machinery space shall be determined from the formula: |
where—
| a = | volume of the passenger spaces, as defined in Regulation 2 of this Chapter, which are situated below the margin line, before (or abaft) the machinery space, and |
| v = | whole volume of the portion of the ship below the margin line before (or abaft) the machinery space. |
| (d) | In the case of a ship which is permitted under paragraph (c) of Regulation 27 of Chapter III to carry a number of persons on board in excess of the lifeboat capacity provided, and is required under paragraph (d) of Regulation 1 of this Chapter to comply with special provisions, the uniform average permeability throughout the portion of the ship before (or abaft) the machinery space shall be determined from the formula: |
| b = | the volume of the spaces below the margin line and above the tops of floors, inner bottom, or peak tanks, as the case may be, which are appropriated to and used as cargo spaces, coal or oil fuel bunkers, storerooms, baggage and mail rooms, chain lockers and fresh water tanks, before (or abaft) the machinery space; and |
| v = | whole volume of the portion of the ship below the margin line before (or abaft) the machinery space. |
In the case of ships engaged on services where the cargo holds are not generally occupied by any substantial quantities of cargo, no part of the cargo spaces is to be included in calculating “b”.
| (e) | In the case of unusual arrangements the Administration may allow, or require, a detailed calculation of average permeability for the portions before or abaft the machinery space. For the purpose of such calculation, the permeability of passenger spaces as defined in Regulation 2 of this Chapter shall be taken as 95, that of spaces containing machinery as 85, that of all cargo, coal and store spaces as 60, and that of double bottom, oil fuel and other tanks at such value as may be approved in each case. |
| (f) | Where a between deck compartment between two watertight transverse bulkheads contains any passenger or crew space, the whole of that compartment, less any space completely enclosed within permanent steel bulkheads and appropriated to other purposes, shall be regarded as passenger space. Where, however, the passenger or crew space in question is completely enclosed within permanent steel bulkheads, only the space so enclosed need be considered as passenger space. |