5. Watertight and Watertight Integrity

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5.1 Decks

All decks exposed to the weather should be watertight, and means should be provided to make any openings weathertight.(see 2.2)

5.2 Hatchways

5.2.1 All hatch openings in the weather deck should be provided with a watertight coaming of not less than 300 mm high. Hatches covering access to deck lockers should be fitted with a means of securing them in the closed position.

5.2.2 Hatches covering normal access to accommodation on working spaces should be operable from both sides and should be fitted with a means of positively securing them in the open and closed position.

5.2.3 It is recommended that hatchways be located on the centre line of the ship or as close thereto as is practical.

5.2.4 It is recommended that in general, hatches be kept closed at sea. It is also recommended that hatchways which are to be kept open for lengthy periods at sea be as small as practical, but never more than 1 metre square in clear area at the top of the coaming.

5.3 Doorways and Companionways

5.3.1 Doorways located above the weather deck which give access to spaces below should be provided with coamings not less than 300 mm high and with weathertight doors.

5.3.2 Such doors should be of efficient construction, permanently and strongly attached to the bulkhead, open outwards and have a means of closure which can be operated from either side.

5.3.3 They should be located as close as practical to the centre line of the ship but if located in the sides of a house, they should be hinged on the forward edge.

5.3.4 Companion hatch openings from a cockpit or recess which give access to spaces below the weather deck should be fitted with a coaming the top of which is at least 300 mm above the sole of the cockpit or recess. The maximum breadth of the opening in a companion hatch should not exceed 1 metre.

5.3.5 On existing vessels where adequate coamings are not fitted, shifting boards should be fitted to a height of 300 mm and have adequate visible adjacent storage.

5.4 Skylights

5.4.1 All skylights should be of weathertight construction and should be located on the centre line of the ship or as near thereto as practical. If they are of the opening type, they should be fitted with a coaming at least 300 mm above the deck and with efficient means of closing.

5.4.2 Any openings in the weather deck designed as skylights should incorporate toughened safety glass or an equivalent of at least 6 mm thickness. They should be provided with portable covers which can be secured in place in the event of breakage.

5.5 Portlights and Windows

5.5.1 Portlights, scuttles and windows to spaces below the weather deck, in a deckhouse or superstructure protecting openings leading below the weather deck should be of efficient construction and fitted with permanently attached deadlights capable of being closed weathertight.

5.5.2 In a new ship a portlight or window should not be fitted in the main hull below the weather deck, unless the glazing material and its method of fixing in the frame are equivalent in strength to that required for the structure in which it is fitted.

5.5.3 In a new ship, a scuttle should not be provided to a space situated below the weather deck.

5.5.4 It is recommended that a scuttle does not exceed 250 mm in diametre or equivalent in size.

5.5.5 If windows are to be fitted in spaces above the weather deck which protect openings leading below the weather deck, they should be of weathertight construction. Portable covers should be provided at the rate of 50% for each size of window, which can be secured weathertight in the event of breakage.

5.5.6 The portlights, scuttles and windows described above should incorporate toughened safety glass or an equivalent of at least 6 mm in thickness.

5.6 Ventilators

5.6.1 Ventilators should be of efficient construction and provided with a permanently attached means of weathertight closure.

5.6.2 Ventilators should be kept as far inboard as practical and have a height to the lower edge of the opening of not less than 915 mm above the weather deck.

5.6.3 Ventilators which must be kept open ( e.g. for the supply of air to machinery or for the discharge of noxious or flammable gases) should be specially considered with respect to their location and height above deck given that they may become downflooding points.

5.6.4 Ventilators should be positioned such that they will not interfere with the safe operation of the vessel or where they can be caused damage by such operations.

5.7 Air Pipes

5.7.1 Air pipes greater than 10 mm inside diametre serving fuel or other tanks should be of efficient construction and be provided with a permanently attached means of weathertight closure. Air pipes should be in accordance with the Marine Machinery Regulations schedule XV Part 1 Div II Sections 78 to 89.

5.7.2 Where located on the weather deck they should extend a minimum of 300 mm above the weatherdeck and be fitted with a gooseneck.

5.8 Sea Inlets and Discharges

5.8.1 All openings below the weather deck should be fitted with an efficient means of closure.

5.8.2 Where the opening is for the purpose of an inlet or discharge below the waterline, it should be fitted with a seacock, valve or other means of closure which is readily accessible in an emergency.

5.8.3 Where the opening is for a log or any other sensor which is capable of being withdrawn, it should be fitted in a watertight manner and provided with an effective means of closure when such a fitting is removed.

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