The Fishing Vessels (Safety Provisions) Rules 1975

Rule 82(2)

SCHEDULE 5 CALCULATION OF CUBIC CAPACITY OF LIFEBOATS

1.  Subject to the provisions of paragraph 4 below, the cubic capacity of a lifeboat for the purposes of these Rules shall be measured in cubic metres and shall be determined by Stirling's (Simpson's) Rule, which may be considered as given by the following formula:—

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• L denotes the length of the lifeboat in metres from the inside of the shell at the top of the stem to the corresponding point at the top of the stern post; in the case of a lifeboat with a square stern the length is measured to the inside of the top of the transom; and

• 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 corresponding to the two ends of the lifeboat shall be considered negligible).

The areas A, B, C shall be deemed to be given in square metres by the successive application of the following formula to each of the three cross-sections:—

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• h denotes the depth measured in metres inside the shell from the keel to the level of the gunwale, or, in certain cases, to a lower level as determined hereafter; and a, b, c, d, e denote the horizontal breadths of the lifeboat measured in metres inside the shall at the upper and lower points of the depth and at the three points obtained by dividing h into four equal parts (a and e being the breadths at the extreme points, and c at the middle point of h).

The capacity of a square-sterned lifeboat shall be calculated as if the lifeboat had a pointed stern.

2.  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-section A or C shall be deemed to be the depth amidships plus 1 per cent of the length of the lifeboat.

3.  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 calculations exceed the actual depths at these points.

4.  Unless the owner of the lifeboat requires the cubic capacity to be determined by exact measurements, the cubic capacity of a lifeboat constructed of wooden planks may be assumed to be the product of the length, the breadth and the depth multiplied by 0.6 if this formula does not give a greater capacity than that obtained by the formula set out in paragraph 1 above. The dimensions shall be measured in the following manner:—

Length—from the intersection of the outside of the planking with the top of the stem to the corresponding point at the stern post, or in the case of a square-sterned lifeboat, to the after side of the top of the transom;

Breadth—from the outside of the planking at the point where the breadth of the lifeboat is greatest;

Depth—amidships inside the planking from the keel to the level of the top of the gunwale, but the depth used in calculating the cubic capacity may not in any case exceed 45 per cent of the breadth.

5.  The cubic capacity of a motor lifeboat or a lifeboat fitted with other propelling gear shall be obtained from the gross capacity by deducting a volume equal to that occupied by the motor and its accessories or the gearbox of the other propelling gear.