Chapter:	369C	Title:	MERCHANT SHIPPING (INSTRUCTIONS TO SURVEYORS) (PASSENGER SHIPS) REGULATIONS	Gazette Number:
Regulation:	18	Heading:	Watertight transverse bulkheads	Version Date:	30/06/1997

(1) Plating: Transverse bulkheads shall be watertight up to the bulkhead deck, and shall have plating of not less thickness than required by Table 4, Appendix II.
Where a transverse bulkhead is at the end of a stokehold space, the lower part of the bulkhead plating to a height of at least 24 inches above the stokehold floor, shall be at least .1 inch thicker than given by the Table.
Where a transverse bulkhead is at the end of a bunker space, the lowest strake shall be at least 36 inches high and .1 inch thicker than given by the Table. In all other cases the lowest strake shall be at least .04 inch thicker, except that any limber plates shall be .1 inch thicker.
(2) Boundary Angles: These may be single and shall be at least .1 inch thicker than the bulkhead plating required by the Table.
(3) Stiffeners:

(a) These shall be in accordance with Table 1 or Table 2, Appendix II, in association with a spacing of 30 inches. Other forms of stiffener may be adopted if they provide not less strength and stiffness than those tabulated, and the spacing of stiffeners may be increased up to a maximum of 36 inches, provided they be correspondingly increased in strength and stiffness.
The lower end of each stiffener is to be attached to the shell plating, to the inner bottom plating or to efficient horizontal plating.
(b) At each deck level which forms the top of a system of stiffeners, plating is to be provided of a character which win ensure horizontal rigidity in the bulkhead.
(c) In the case of hold stiffeners connected to the inner bottom plating the lower bracket or its connecting angle shall extend over the floor adjacent to the bulkhead; the upper bracket is to be connected to angles which extend over the beam space, or other effective means shall be adopted for securing the necessary structural rigidity at these parts.
(d) Where stiffeners are cut in way of watertight doors in the lower part of a bulkhead, the opening is to be suitably framed and bracketed, and a tapered web plate or buttress, stiffened on its edge, is to be fitted at each side of the door from the base of the bulkhead to well above the door opening.
Where stiffeners are not cut, but where the space between stiffeners has to be increased on account of watertight doors in 'tween deck bulkheads, the stiffeners at the sides of the doorway shall be increased in depth and strength.
In all cases where stiffeners are cut, or are widely spaced, the efficiency shall be at least equal to that of the unpierced bulkhead, without taking the door-frames into consideration.
The frames of watertight doors are to be well fitted and strongly connected to the bulkhead.

(a) The rivets in seams, and connections of plating and boundary bars of bulkheads shall be spaced not more than 4 1/2 diameters centre to centre, except on the shell flange of boundary angles where they may be 5 diameters centre to centre.
(b) Where the distance below the bulkhead deck is more than 35 feet, the boundary angles shall be double riveted in both flanges, and the vertical connection of plates shall also be double riveted.
(c) The rivets connecting stiffeners to bulkhead plating shall be spaced not more than seven diameters centre to centre, and in the case of stiffeners having no bracket attachment, they shall be spaced four diameters for 15 per cent of their length each end.