Special rules are laid down for the opening and closing of all doors, hatches, valves and other watertight openings situated near or below the waterline .
Kukho imithetho ebekiweyo ukwenzela ukuvulwa nokuvalwa kweminyango, izikroba, ivalvu kunye nezivalo ezingangeni manzi ezibekwe kufutshane okanye ngezantsi komgca wamanzi.