rQ7 



SAFETY OF LIFE AT SEA 



(b) For example, the capacity in cubic feet (or cubic metres) of a lifeboat, 

 calculated by the aid of Stirling's Rule, may be considered as given by the 

 following formula: — 



t 



Capacity = ^ (4A+2B+4C) 



being the length of the lifeboat in feet (or metres) from the inside of the 

 planking or plating at the stem to the corresponding point at the stern post : 

 in the case of a lifeboat with a square stern, the length is measured to the 

 inside of the transom. 



A, B, C denote respectively the areas of the cross-sections at the quarter- 

 length forward, amidships, and the quarter-length aft, which correspond to the 

 three points obtained by dividing L into four equal parts. (The areas corre- 

 sponding to the two ends of the lifeboat are considered negligible.) 



The areas A. B, C shall be deemed to be given in square feet (or square 

 metres) by the successive application of the following formula to each of 

 the three cross-sections — 



t- 

 Area= — (a + 4b + 2c-l-4d-fc) 



h being the depth measured in feet (or in metres) inside the planking or plating 

 from the keel to the level of the gunwale, or, in certain cases, to a lower level 

 as determined hereafter. 



a, b, c, d. e denote the horizontal breadths of the lifeboat measured in 

 feet (or in metres) at the upper and lower points of the depth and at the three 

 f)oints obtained by dividing h into four equal parts (a and e being the breadths 

 at the extreme point, and c at the middle point of h). 



(c) If the sheer of the gunwale, measured at the two points situated at a 

 quarter of the length of the lifeboat from the ends, exceeds 1 per cent, of the 

 length of the lifeboat the depth employed in calculating the area of the cross- 

 sections A or C shall be deemed to be the depth amidships plus 1 per cent, 

 of the length of the lifeboat. 



(d) If the depth of the lifeboat amidships exceeds 45 per cent, of the 

 breadth, the depth employed in calculating the area of the amidship cross- 

 section B shall be deemed to be equal to 45 per cent, of the breadth, and 

 the depth employed in calculating the areas of the quarter-length sections A 

 and C is obtained by increasing this last figure by an amount equal to 

 1 per cent, of the length of the lifeboat, provided that in no case shall the 

 depths employed in the calculation exceed the actual depths at these points. 



(e) If the depth of the lifeboat is greater than 4 feet (or 122 centimetres) 

 the number of persons given by the application of this Rule shall be reduced 

 in proportion to the ratio of 4 feet (or 122 centimetres) to the actual depth, 

 until the lifeboat has been satisfactorily tested afloat with that number of 

 persons on board, all wearing lifejackets. 



(/) The Administration shall impose, by suitable formulae, a limit for 

 the number of persons allowed in lifeboats with very fine ends and in 

 lifeboats very full in form. 



Ch. 3 



763-778 O - 65 - 28 



