«STRENGTH, CONSTRUCTION AND WATERTIGHT SUBDIVISION 2.1 Definitions (Regulation 2) The following notes are for the guidance of surveyors in the ...»
126.96.36.199 In order to satisfy the requirements of Schedule 6 and 10 to Merchant Shipping Notice MSN 1698 (M), inlets and discharges led through the shell below the bulkhead deck should be arranged as follows:Discharges from spaces below the bulkhead deck (i) Efficient means shall be provided for the drainage of all watertight decks below the bulkhead deck and any drainage pipes shall be so fitted with valves or otherwise arranged as to avoid the danger of water passing from a damaged to an undamaged compartment.
MSIS003/PT 2/REV 1.01/PAGE 21 (ii) Where one automatic non-return valve is fitted in a ship which is marked with a summer load line, the means of closure should be from a position above the bulkhead deck or the freeboard deck, whichever is the higher. See figure 188.8.131.52.(ii).
(iii) Where the vertical distance from the inboard end of the discharge pipe to the summer load waterline exceeds 0.0lL, (where L is the length of the ship as defined in the Merchant Shipping (Load Line) Regulations 1998, two automatic non-return valves having no positive means of closure may be fitted. In any ship which is not marked with a summer load waterline the vertical distance shall be measured to the ships deepest subdivision load waterline; one such value shall be situated as close to the ship's shell as practicable and substantially connected thereto. The inboard valve shall, where practicable, be fitted above the deepest load waterline; where this is not practicable, a locally controlled sluice valve interposed between the two automatic non-return valves shall be fitted. See figures 184.108.40.206.(iii) a) and b).
One automatic non-return valve at the shell with positive means of closure above the bulkhead or freeboard deck and fitted with open/shut indicator.
Two automatic non-return valves without positive means of closure. One valve fitted at the shell and one valve above the deepest load waterline and always accessible under service conditions.
Two automatic non-return valves without positive means of closure, one of which is fitted at the shell, and a readily accessible locally controlled sluice valve fitted between the two non-return valves.
The requirements are included in paragraph 7 of Schedule 6 of Merchant Shipping Notice MSN 1698 (M).
2.12.5 Drainage of vehicle spaces 220.127.116.11 In vehicle ferries or similar ships with large open or enclosed spaces, means should be provided to free rapidly such spaces of water which may have accidentally entered the ship, or may be present as a result of operating a fire extinguishing system, because of the adverse effect of such water on stability.
18.104.22.168 Normally, scuppers of 152 mm diameter should be fitted on each side of such an enclosed space, and spaced not more than 9.15 m apart when the maximum breadth of the deck in the space is 18.3 m or less. When the maximum breadth is in excess of 18.3 m, the scupper spacing should be decreased in direct proportion to the maximum breadth to 18.3 m.
22.214.171.124 In ships having ramped vehicle decks or unusual sheer on the deck the number and spacing of the scuppers will require to be determined having regard to such features.
126.96.36.199 If the scuppers are fitted with valves having positive means of closure, the position for operating such means should be accessible from outside the vehicle spaces and above the bulkhead deck.
188.8.131.52 The efficiency of the scuppers should not be impaired by kerbs, fenders, etc, and openings in gratings should be sufficiently large to prevent them becoming choked by rubbish.
184.108.40.206 Before the ship is permitted to enter into service the efficiency of the scupper arrangements is to be demonstrated to show that there is no build-up of water on any portion of the deck and that the deck is rapidly cleared of water.
220.127.116.11 The freeing arrangements for open spaces will be specially considered by the Certifying Authority in view of the greater risk which they present, and if it is considered that such spaces could hazard the safety of the ship, they should be enclosed.
2.12.6 Water-closets When water-closets of the under-waterline type are to be fitted, plans should be specially submitted for acceptance.
18.104.22.168 Every ash chute, rubbish chute, etc., should have a watertight cover and, if the inboard opening is below the bulkhead deck, be fitted with an automatic non-return valve in the chute in a readily accessible position above the deepest subdivision load waterline.
22.214.171.124 Where an automatic non-return valve is to be fitted, the valve should be of the horizontal balanced type and should normally be kept closed and provided with local means for securing it in a closed position.
When the chute is not in use, both the cover and the valve should be kept closed and secured in accordance with Regulation 22(8) and a permanent notice to this effect should be fixed near the hopper. In ships constructed before 1 September 1984 the requirements of this paragraph should not apply to ash ejectors and expellers the inboard openings of which are in the ship’s stokehold and below the deepest subdivision load waterline. Such ejectors and expellers should be fitted with means which will prevent water entering the ship.
2.12.8 Storm valve
126.96.36.199 The storm valve fitted at the ship's side is to be of a substantial back-balanced type, or of a type in which the valve face is at an angle of not less than 15° to the vertical when closed. Valves mounted on a spigot, instead of
being attached directly to the shell, may be accepted provided that the spigot is:
(ii) efficiently welded and bracketed to the shell; and (iii) its thickness is not less than the thickness of the shell plating in which it is situated.
2.12.9 Closure versus heel In all ships the incidence of the calculation made under the provisions of Schedule 3 to Merchant Shipping Notice MSN 1698 (M) relating to stability and angle of heel in the damaged condition will be taken into account in accepting the means of closing scuppers, discharges and other side openings from spaces above the margin line.
2.13 Side and Other Openings Above the Bulkhead Deck (Regulation 16) 2.13.1 Side scuttles The provisions of paragraph 2.12.2 of these Instructions also apply to side scuttles fitted to openings in the ship's sides above the margin line.
188.8.131.52 Where proposed window sizes exceed those defined within a recognised standard, these may be accepted providing they are situated in the fourth and higher tiers of superstructures for category 1 windows, and in the third and higher tiers of superstructures for category 2 windows. The Certifying Authority may require the glass in such windows to be thicker than the maximum standard size.
184.108.40.206 Category 1 means windows situated in the ships’ sides and in exposed casings or deckhouse sides set inboard not more than 4% of the breadth of the ship or 1.5 m whichever is the greater, and windows facing forward.
220.127.116.11 Category 2 means windows situated in the side screens and in exposed casings or deckhouse sides set inboard more than 4% of the breadth of the ship, or 1.5 m whichever is the greater.
2.13.3 Deadlights 18.104.22.168 Deadlights should comply with the following:i) In enclosed spaces below the first deck above the bulkhead deck or freeboard deck, whichever is the higher, efficient hinged deadlights which can be effectively closed and secured watertight must be fitted to all side scuttles.
(ii) In other enclosed superstructures, side scuttles and windows should be provided with deadlights or shutters, which may be fixed or portable, except that only fixed deadlights or shutters should be fitted to side scuttles and windows situated in the bridge front of the first tier of superstructures immediately above the weather-deck. Portable deadlights and shutters should be provided to the extent shown in the following table:
(iii) Shutters should be of steel of not less than 3.5 mm in thickness, or of an equivalent material, and provided with means of securing them to the frame sufficient to withstand the pressures likely to be experienced in service.
22.214.171.124 Glass for side scuttles and windows fitted in all ships should be in accordance with paragraph 1.3 of these Instructions.
126.96.36.199 The number of spare glasses which are to be provided for the side scuttles and windows fitted in ships of Classes I and II should not be less than 4% of the total number of glasses for each size fitted, with a minimum of 2 glasses for each size.
188.8.131.52 For ships of Class II(A) the number of spare glasses should not be less than 2 glasses for each size of side scuttle and window.
2.14 Construction and Testing of Watertight Doors (Regulation 17) 2.14.1 Construction 184.108.40.206 Every watertight door should be of such design, material and construction as will maintain the integrity of the watertight bulkhead in which it is fitted. For this purpose it may be necessary, particularly with large sliding watertight doors, to arrange points of support in way of the leading and trailing edges of the door at the closed position. The design stress in the door should be such that a factor of safety of approximately three, based on the ultimate tensile strength of the material, will be obtained.
220.127.116.11 Every sliding watertight door should be fitted with rubbing faces of brass or similar material which may be fitted either on the door itself or on the door frame, and which, if they are less than 25 mm in width, should be fitted in recesses. In the case of ships constructed after 1 February 1992, other methods of sealing sliding watertight doors may be acceptable.
18.104.22.168 If screw gear is used for operating such a door, the screw and nut should be of suitable metals which are resistant to corrosion.
22.214.171.124 The frame of every vertically sliding watertight door should have no groove at the bottom thereof in which dirt may lodge. The bottom of such a frame, if it is of skeleton form, should be so arranged that dirt cannot lodge therein. The bottom edge of every such door should be tapered or bevelled.
126.96.36.199 Every vertically sliding watertight door which is operated by power should be so designed and fitted that, if the power supply ceases, there should be no danger of the door dropping.
188.8.131.52 Every horizontally sliding watertight door should be so installed as to prevent its moving if the ship rolls, and if necessary a clip or other suitable device should be provided for that purpose. The device should not interfere with the closing of the door when the door is required to be closed.
MSIS003/PT 2/REV 1.01/PAGE 27 184.108.40.206 In the case of sliding watertight doors, care should be taken to ensure a satisfactory connection where the door frame beds on to the bulkhead plating. In compartments where oil fuel may catch fire, these connections should be metal to metal. Any jointing used should not be adversely affected by heat or the local environment.
220.127.116.11 Every watertight door should be tested at the works in the presence of the surveyor by hydraulic pressure equivalent to the head of water measured from the bottom of the door to the margin line in way of the bulkhead to which the door is to be fitted, but in no case should the test pressure be less than 6 m head for sliding doors or less than 3 m head for hinged doors. The framework to which the door frame is secured for the purpose of testing at the works should not give greater reinforcement to the frame than the stiffening of the bulkheads to which it is to be fitted. The purpose of the test is to show whether the door is of sufficient strength and reasonably watertight under pressure. The rate of leakage and deflection of the door at the centre should be reported.
18.104.22.168 After a satisfactory hydraulic test, each watertight door and its frame should be stamped with the following identification marks:
22.214.171.124 After being fitted in place on the bulkhead in the ship, the door and the attachment of the door frame to the bulkhead should be included in the hose test required for watertight bulkheads.
126.96.36.199 All sliding watertight doors should be operated by hand and, if power operated, by power in the presence of the surveyor, who should note and record the times taken to close the doors.
188.8.131.52 The surveyor should see that the warning signals are efficient and comply with the provisions of paragraph 184.108.40.206 (ii) of these Instructions and that the indicators register properly.
220.127.116.11 Hinged watertight doors are to be inspected and tried. The surveyor should see that the lever operated clips are in order and that the joints are watertight.