Merchant Shipping (Safety and Load Line Conventions) Act 1932

Effective Length of Enclosed Superstructures with Middle Line Openings.

RULE LII Enclosed Superstructure with Middle Line Openings in the deck not Provided with Permanent Means of Closing.

Where there is an enclosed superstructure with one or more middle line openings in the deck not provided with permanent means of closing (see Rules VIII to XVI), the effective length of the superstructure is determined as follows :—

(1) Where efficient temporary closing appliances are not provided for the middle line deck openings (see Rule XLV), or the breadth of opening is 80 per cent. or more of the breadth B₁, of the superstructure deck at the middle of the opening, the ship is considered as having an open well in way of each opening, and freeing ports are to be provided in way of this well. The effective length of superstructure between openings is governed by Rules XLVII, XLIX, and L.

(2) Where efficient temporary closing appliances are provided for middle line deck openings and the breadth of opening is less than .8 B_1, the effective length is governed by Rules XLVII, XLIX, and L, except that where access openings in 'tween deck bulkheads are closed by Class 2 closing appliances, they are regarded as being closed by Class 1 closing appliances in determining the effective length. The total effective length is obtained by adding to the length determined by (1) the difference between this length and the length of the ship modified in the ratio of—

where b = breadth of deck opening;

where is greater than .5 it is taken as .5.