Section 53

Watertight decks, trunks, tunnels, duct keels and ventilators shall be of the same strength as watertight bulkheads at corresponding levels. The means used for making them watertight, and the arrangements adopted for closing openings in them, shall be to the satisfaction of the Director. Watertight ventilators and trunks shall be carried at least up to the bulkhead deck in passenger ships and up to the freeboard deck in cargo ships.

(21

In ro-ro passenger ships, where a ventilation trunk passing through a structure penetrates the bulkhead deck, the trunk shall be capable of with-standing the water pressure that may be present within the trunk, after having taken into account the maximum heel angle allowable during intermediate stages of flooding, in accordance with sub-regulation (6) of regulation 36.

13)

In ro-ro passenger ships, where all or part of the penetration of the bulkhead deck is on the main ro-ro deck, the trunk shall be capable of with-standing impact pressure due to internal water motions (sloshing) of water trapped on the ro-ro deck.

In ro-ro passenger ships, in ships constructed before 1st. July, 1997, the requirements of sub-regulations (2) and (3) shall apply not later than the date of the fi.rst periodical survey after 1st. July, 1997.

After completion, a hose or flooding test shall be applied to watertight decks and a hose test to watertight trunks, tunnels and ventilators.

577

Watertight integrity of passenger ships above margin line.