(a) 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 Administration. Watertight ventilators
and trunks shall be carried at least up to the immersion limit line.
(b) After completion, a hose or flooding test
shall be applied to watertight decks and a hose test to watertight
trunks, tunnels and ventilators.