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Code of Practice
6 Water Freeing Arrangements
6.1 When a deck is fitted with bulwarks such that shipped water may be trapped behind them, the bulwarks should be provided with efficient freeing ports.
6.2 The area of freeing ports should be at least 10% of that part of the bulwark area which extends for 2/3 of the vessel's length amidships. A freeing port should be located in the lower third of the bulwark height, as close to the deck as practicable.
6.3 A freeing port should be fitted with a grid which has a spacing of not more than 50mm in each direction.
6.4 When a non-return shutter or flap is fitted to a freeing port it should have sufficient clearance to prevent jamming and any hinges should have pins or bearings of non-corrodible material.
6.5 When a vessel has only a small side deck areas in which water can be trapped a smaller freeing port area may be accepted. The reduced are should be based on the volume of water which is likely to become trapped.
6.6 Structures and spaces considered to be non-weathertight should be provided with efficient drainage arrangements.
