2.2.2 Ceiling
is to be laid on the inner bottom under cargo hatchways, but may be
omitted provided that the inner bottom plating is increased by 2 mm.
In any ship which is regularly to be discharged by grabs, ceiling
is to be laid on the inner bottom, and the inner bottom plating increased
by 3 mm. Alternatively, the ceiling may be omitted provided that the
inner bottom plating is increased in thickness by a minimum of 5 mm.
The ceiling is to be 76 mm thick in softwood or 65 mm thick in hardwood,
and is to be laid at right angles to the inner bottom stiffening.
Where it is intended to use plywood or other forms of ceiling of an
approved type instead of planking, the thickness will be considered
for each case. Ceiling is also to be laid over bilges, and fitted
with portable sections which are to be readily removable. The spaces
between the frames at the top of the bilge ceiling are to be closed
by steel plates, wood chocks, cement or other suitable means. Inner
bottom manhole covers or fittings, where projecting above the inner
bottom plating, are to be provided with a steel protection coaming
around each manhole, and a wood or steel cover is to be fitted.
2.2.3 Where
plated decks are sheathed with wood or approved compositions, the
minimum thicknesses given in Pt 4, Ch 1, 4.2 Deck plating, Pt 3, Ch 5, 2 Deck structure and Pt 3, Ch 6, 2 Deck structure may be reduced by 10 per
cent for a 50 mm sheathing thickness or five per cent for 25 mm, with
intermediate values in proportion. The steel deck is to be coated
with a suitable material in order to prevent corrosive action, and
the sheathing or composition is to be effectively secured to the deck. See also the fire protection requirements relating to deck
coverings in the relevant SOLAS - International Convention for the Safety of Life at Sea Regulations
or Pt 6, Ch 3, 4 Refrigeration plant, pipes, valves and fittings as applicable.
2.2.4 Where
cargo battens or equivalent are fitted in the holds of dry cargo ships,
the descriptive note `SF' will be entered in the Register Book. The
battens, when fitted, are to extend from above the upper part of the
bilge to the underside of beam knees in the holds, and in all cargo
spaces in the 'tween decks and superstructures, up to the underside
of beam knees. Wood cargo battens are to be not less than 50 mm in
thickness, and the clear space between adjacent rows is, in general,
not to exceed 230 mm. The dimensions and spacing of battens made of
other materials will be considered. Nets may be adopted in lieu of
battens, and other alternative proposals will be specially considered.
For arrangements in way of a refrigerated hold, see
Pt 6, Ch 3, 4 Refrigeration plant, pipes, valves and fittings.