8.9.1 General
a) The provisions of this sub-article are applicable only to
those discharges which remain open during the normal
operation of a ship. For discharges which must necessarily
be closed at sea, such as gravity drains from topside
ballast tanks, a single screw-down valve operated from
the deck may be accepted.
b) The position of the inboard end of discharges is related
to the timber summer