(1) Two gate valves controlled from the working
deck of the chute instead of the non-return valve with a positive
means of closing from a position above the freeboard deck which comply
with the following requirements are acceptable:
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(a) the lower gate valve shall be controlled from
a position above the freeboard deck. An interlock system between the
two valves shall be arranged;
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(b) the inboard end shall be located above the
waterline formed by an 8.5° heel to port or starboard at a draft
corresponding to the assigned summer freeboard, but not less than
1,000 mm above the summer waterline. Where the inboard end exceeds
0.01L above the summer waterline, valve control from the freeboard
deck is not required, provided the inboard gate valve is always accessible
under service conditions; and
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(c) alternatively, the upper and lower gate valves
may be replaced by a hinged weathertight cover at the inboard end
of the chute together with a discharge flap. The cover and flap shall
be arranged with an interlock so that the discharge flap cannot be
operated until the hopper cover is closed.
(2) The entire chute, including the cover, shall
be constructed of material of substantial thickness.
(3) The controls for the gate valves and/or hinged
covers shall be clearly marked: "Keep closed when not in use".
(4) Where the inboard end of the chute is below
the freeboard deck of a passenger ship or the equilibrium waterlines
of a cargo ship to which damage stability requirements apply, then:
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(a) the inboard end hinged cover/valve shall be
watertight;
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(b) the valve shall be a screw-down non-return
valve fitted in an easily accessible position above the deepest load
line; and
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(c) the screw-down non-return valve shall be controlled
from a position above the bulkhead deck and provided with open/closed
indicators. The valve control shall be clearly marked: "Keep closed
when not in use".