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Code of Practice
5 Weathertight Integrity
A vessel should be designed and constructed in a manner which will prevent the ready ingress of sea water and in particular comply with the following requirements:-
5.1.1 General requirements
5.1.1.1 A hatchway which give access to spaces below the weather deck should be of efficient construction and be provided with efficient means of weathertight closure.
5.1.1.2 A cover to a hatchway should be hinged, sliding, or permanently secured by other equivalent means to the structure of the vessel and be provided with sufficient locking devices to enable it to be positively secured in the closed position.
5.1.1.3 A hatchway with a hinged cover which is located in the forward portion of the vessel should normally have the hinges fitted to the forward side of the hatch, as protection of the opening from boarding seas.
5.1.2 Hatchways which are open at sea
In general hatches should be kept closed at sea. However, a hatch (other than one referred to in 5.2.2) which is to be open at sea for lengthy periods should be:-
.1 kept as small as practicable, but never more than 1m² in plane area at the tope of the coaming;
.2 located on the centre line of the vessel or as close thereto as practicable;
.3 fitted such that the access opening is at least 300mm above tope of the adjacent weather deck at side.
5.2 Doorways and Companionways
5.2.1 Doorways located above the weather deck
5.2.1.1 A doorway located above the weather deck which gives access to spaces below should be provided with a weathertight door. The door should be of efficient construction, permanently attached to the bulkhead, not open inwards, and sized such that the door overlaps the clear opening on all sides, and has efficient means of closure which can be operated from either side.
5.2.1.2 A doorway should be located as close as practicable to the centre line of the vessel. However, if hinged and located in the side of a house, the door should be hinged on the forward edge.
5.2.1.3 A doorway which is either forward or side facing should be provided with a coaming the top of which is at least 300mm above the weather deck. A coamings may be portable provided it is permanently secured to the structure of the vessel and can be locked in position.
5.2.2 Companion hatch openings
5.2.2.1 A companion hatch opening from a cockpit or recess which gives access to spaces below the weather deck should be fitted with a coaming, the tope of which is at least 300mm above the sole of the cockpit or recess.
5.2.2.2 When washboards are used to close a vertical opening they should be so arranged and fitted that they will not become dislodged in any event.
5.2.2.3 The maximum breadth of the opening of a companion hatch should not exceed 1 metre.
5.3 Skylights
5.3.1 A skylight should be of efficient weathertight construction and should be located on the centre line of the vessel, or as near thereto as practicable, unless it is required to provide a means of escape form a compartment below deck.
5.3.2 If a skylight is an opening type it should be provided with efficient means whereby it can be secured in the closed position.
5.3.3 In a new vessel, a skylight which is provided as a means of escape should be openable from either side.
5.3.4 Unless the glazing material and its method of fixing in the frame is equivalent in strength to that required for the structure in which it is fitted, a portable "blank" should be provided which can be efficiently secured in place in event of breakage of the glazing.
5.4 Portlights
5.4.1 A portlight to a space below the weather deck or in a stop, recess, raised deck structure, deckhouse or superstructure protecting openings leading below the weather deck should be of efficient construction.
5.4.2 In a new vessel, a portlight 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.
5.4.3 In a new vessel, an opening portlight should not be provided to a space situated below the weather deck.
5.4.4 In an existing vessel, a portlight below the weather deck and not provided with an attached deadlight should be provided with a "blank" (at the rate of 50% for each size of portlight in the vessel), which can be efficiently secured in place in the event of breakage of the portlight.
5.4.4.1 Such a "blank" is not required for a non-opening portlight which satisfies 5.4.2.
5.4.5 An opening portlight should not exceed 250mm in diameter or equivalent area.
5.5 Windows
5.5.1 In a vessel when a window is fitted in the main hull below the weather deck it should provide watertight integrity (and be of strength compatible with size) for the intended area of operation of the vessel.
5.5.2 In a new vessel , a 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 A window fitted to a space above the weather deck or in the side of a cockpit or recess should be of efficient weathertight construction.
5.5.4 In a vessel which operates more than 60 miles from a safe haven (area category 0 or 1), portable "blanks" should be provided (at the rate of 50% for each size of window), which can be efficiently secured in place in the event of breakage of a window.
5.5.4.1 Such "blank" is not required for a window which meets the requirements of 5.5.2.
5.6 Ventilators and Exhausts
5.6.1 A ventilator should be efficient construction and be provided with a permanently attached means of weathertight closure.
5.6.2 A ventilator should be kept as far inboard as practicable and the height above the deck of the ventilator opening should be sufficient to prevent the ready admission of water when the vessel is heeled.
5.6.3 A ventilator 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 its location and height above deck having regard to 5.6.2 and the downflooding angle.
5.6.4 An engine exhaust outlet which penetrates the hull below the weather deck should be provided with means to prevent backflooding into the hull through the exhaust system. The means may be provided by system design and/or arrangement, built-in valve or a portable fitting which can be applied in an emergency.
5.7 Air Pipes
5.7.1 When located on the weather deck, an air pipe should be kept as far inboard as possible and have a height above deck sufficient to prevent inadvertent flooding when the vessel is heeled.
5.7.2 An air pipe, of greater than 10mm inside diameter, serving a fuel or other tank should be provided with a permanently attached means of weathertight closure.
5.8 Sea Inlets and Discharges
5.8.1 An opening below the weather deck should be provided with an efficient means of closure.
5.8.2 When an opening is for the purpose of an inlet or discharge below the waterline it should be fitted with a seacock, valve or other effective means of closure which is readily accessible in an emergency.
5.8.3 When an opening is for a log or any other sensor which is capable of being withdrawn it should be fitted in an efficient watertight manner and provided with an effective means of closure when such a fitting is removed.
5.8.4 Inlet and discharge pipes form water closets should be looped up within the hull to the underside of deck and shell fittings provided as required by 5.8.2. When the rim of a toilet is either below or less than 300mm above the deepest waterline of the vessel, anti-syphon measures should be provided.
5.9 Materials for Valves and Associated Piping
5.9.1 A valve or similar fitting attached to the side of the vessel below the waterline, within an engine space or other high fire risk area, should be normally of steel, bronze, copper or other equivalent material.
5.9.2 When unprotected plastic piping is used it should be of good quality and of a type suitable for the intended purpose. If fitted within an engine space or fire risk area, a means should be provided to stop the ingress of water in the event of the pipe being damaged.
