Hong Kong Regulations

MERCHANT SHIPPING (INSTRUCTIONS TO SURVEYORS) (PASSENGER SHIPS) REGULATIONS - REGULATION 18

Watertight transverse bulkheads

(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.

(4) Riveting:

   (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.

(5) Collision Bulkhead: The scantlings, both of plates and stiffeners shall
not be less than are required for ordinary transverse bulkheads having
stiffeners at 30 inch spacing, but the spacing of the stiffeners is not to
exceed 24 inches. Where this bulkhead extends above the bulkhead deck as
required by paragraph 14, the extension is to have the same scantlings as an
ordinary upper 'tween deck watertight bulkhead, and is to be made
weathertight.