35.—(1) All sidescuttles below the margin line shall be of the non-opening type.
(2) (a) All inlets and discharges in the shell plating shall be fitted with effective and accessible arrangements for preventing the accidental admission of water into the ship. Lead or other heat sensitive material shall not be used for a pipe fitted outboard of shell valves in inlets or discharges, or such pipe which in the event of fire would give rise to danger of flooding.
(b) (i) Except as provided in sub-paragraph (c), each separate discharge led through the shell plating from spaces below the margin line shall be provided either with one automatic non-return valve fitted with a positive means of closing from above the bulkhead deck, or, alternatively, with two automatic non-return valves without such means, the upper of which is so situated above the deepest subdivision load line as to be always accessible for examination under service conditions, and is of a type which is normally closed.
(ii) Where a valve with positive means of closing is fitted, the operating position above the bulkhead deck shall always be readily accessible, and means shall be provided for indicating whether the valve is open or closed.
(c) Main and auxiliary sea inlets and discharges in connection with machinery shall be fitted with readily accessible cocks or valves between the pipes and shell plating or between the pipes and fabricated boxes attached to the shell plating.
(3) All cocks and valves for sea inlets and discharges below the bulkhead deck and all fittings outboard of such cocks and valves shall be made of steel, bronze or other approved ductile material. No ordinary cast iron or similar material shall be used.