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CHAPTER II - CONSTRUCTION - SUBDIVISION AND STABILITY

5.1.1 Vessels carrying more than 12 berthed passengers on any voyage, and vessels carrying more than 50 unberthed passengers on home-trade Class III or inland waters Class II voyages shall be so divided by transverse watertight bulkheads that with any one main compartment flooded, the margin line will not be submerged.

5.1.2 Vessels carrying not more than 12 berthed passengers or not more than 100 unberthed passengers on home-trade Class IV, minor waters Class I or II voyages, or not more than 50 unberthed passengers on home-trade Class III or inland waters Class II voyages shall be so constructed that with any one main compartment flooded, the margin line will not be submerged.

5.1.3 To provide the required buoyancy, vessels subject to subsection 5.1.2 may be fitted with a suitable closed-cell buoyant material, or subdivided into watertight compartments.

5.1.4 Subdivision calculations shall be performed in accordance with a recognized method taking into account the form, draught and other characteristics of the vessel. The factor of subdivision shall be unity.

5.1.5 For the purpose of subsection 5.1.1, the watertight bulkheads to be considered effective, shall be spaced between the collision and the afterpeak bulkheads not less than 10 per cent of the maximum load water line length.

5.1.6 Watertight bulkheads required by subsection 5.1.1 shall not be stepped unless additional subdivision is provided in way of the step to maintain the same measure of safety as that obtained by a plane bulkhead; where a ship can withstand flooding of the two adjacent compartments separated by a stepped bulkhead and no part of such bulkhead is nearer to either of the other bulkheads bounding the adjacent compartments than is permitted by subsection 5.1.5, the step will be acceptable.

5.1.7 If a watertight bulkhead is recessed, the recess shall be inboard from the ship's side by at least one-fifth the beam amidships measured at right angles to the centre line at the level of the load water line; otherwise, the bulkhead shall comply with the requirements for a stepped bulkhead.

5.1.8 In the case of vessels where the maximum moulded beam at the deck and at the load water line differ appreciably, the inboard damage penetration may be assumed at a mean position between that corresponding to one-fifth of the maximum moulded beam at the deck, measured inboard at the deck, and that corresponding to one-fifth the maximum moulded beam at the load water line measured inboard at the load water line.

5.1.9 Where a main transverse bulkhead is stepped or recessed, an equivalent plane bulkhead shall be used in determining the subdivision.

5.1.10 Where a main transverse watertight compartment contains local subdivision and it can be shown to the satisfaction of the Regional Director that, after any assumed side damage, the whole volume of the main compartment will not be flooded, a proportionate allowance may be made in the subdivision calculations. In such a case the volume of effective buoyancy assumed on the undamaged side shall not be greater than that assumed on the damaged side.

5.1.11 Means should be provided for verifying the watertight integrity of the vessel and for periodic inspection of the internal structure.

5.2.1 Every vessel must have a collision bulkhead.

5.2.2 Each collision bulkhead required by subsection 5.2.1, must be constructed in accordance with section 5.3, and

1. if the vessel has a long forward superstructure it must extend weather tight to the deck above the bulkhead deck for service on other than home-trade Class IV and minor waters Class I or II. The extension need not be fitted directly above the bulkhead below provided it is located within the limits specified in paragraph 5.2.3.(a) and the part of the deck which forms the step is made effectively weather tight;
   
   
2. shall not be fitted with any type of penetration or opening except as allowed elsewhere in these Standards.

5.2.3 The collision bulkhead shall be:

1. located at least 5 per cent but not more than 8 per cent of the maximum load water line length from the forward perpendicular; and
   
2. installed in a single plane, with no recess or step, and shall be watertight up to the bulkhead deck.

5.2.4 Every vessel shall be provided with watertight bulkheads dividing the space appropriated to the main machinery from other spaces.

5.2.5 Compartments forward of the collision bulkhead are not to be arranged for the carriage of fuel oil or other liquid substances that are flammable.

5.2.6 The tail shaft and the rudder stock shall be fitted with approved watertight glands.

5.3.1 Each watertight subdivision bulkhead, whether transverse or longitudinal, shall be designed in accordance with the rules of an approved classification society, and at least to be capable of remaining watertight with a head of water to the top of the bulkhead.

5.3.2 Each part of the structure of the vessel, forming tanks which are intended to hold liquids, shall be of a design and construction adequate for that purpose.

5.3.3 Each watertight bulkhead must extend to the bulkhead deck and be installed in one plane without steps or recesses insofar as is reasonable and practicable. Any steps or recesses permitted must comply with the section 5.1.

5.4.1 The number of openings in watertight bulkheads shall be reduced to the minimum compatible with the design and proper working of the vessel; satisfactory means shall be provided for closing these openings.

5.4.2 Where pipes, scuppers, electric cables, etc., are carried through watertight subdivision bulkheads, arrangements shall be made to ensure the watertight integrity of the bulkheads.

5.4.3 Valves and cocks not forming part of a piping system shall not be fitted in any bulkhead required to be watertight.

5.4.4 Sluice valves are not permitted in watertight bulkheads.

5.4.5 Heat sensitive materials shall not be used in systems which penetrate watertight subdivision bulkheads, where deterioration of such systems in the event of fire would impair the watertight integrity of the bulkheads.

5.4.6 No doors, manholes, or access openings are permitted in the collision bulkhead below the bulkhead deck.

5.4.7 The collision bulkhead may be pierced below the bulkhead deck by not more than one pipe for dealing with fluid in the forepeak tank, provided that the pipe is fitted with a screwdown valve capable of being operated from above the bulkhead deck, the valve chest being secured inside the forepeak to the collision bulkhead, or this valve may be fitted on the after side of the collision bulkhead provided that the valve is readily accessible under all service conditions and the space in which it is located is not a cargo space.

5.4.8 Not more than one doorway shall pierce a watertight bulkhead in the machinery space; if any such bulkhead is pierced by a doorway, the doorway shall be placed so as to have the sill as high as possible and the outboard vertical edge of such doorway shall be situated at a distance from the vessel's shell plating which is not less than one fifth of the breadth of the vessel.

5.5.1 In every vessel, efficient means shall be provided for closing and making watertight all openings in bulkheads and other structures required to be watertight.

5.5.2 Subject to subsection 5.5.3 watertight doors fitted to any such openings shall be sliding doors. The following rules shall apply:

1. where the vessel has no passenger spaces below the bulkhead deck, the doors may be hand operated;
   
   
2. where the vessel has passenger spaces below the bulkhead deck, the doors shall be power operated and shall be capable of being simultaneously closed from a central station situated on the navigating bridge.

5.5.3 Hinged doors may be fitted to any such openings which are not required to be open at sea. Such doors shall be closed before the voyage commences and shall be kept closed during navigation. Should any of the doors be accessible during the voyage, they shall be fitted with a device which prevents unauthorized opening.

5.5.4 Approved watertight doors may be one of the following types: hinged doors, hand operated sliding doors, and sliding doors which are power operated as well as hand operated.

5.5.5 Every door required by these Standards to be watertight shall be of such design, material and construction as will maintain the integrity of the watertight bulkhead in which it is fitted.

5.5.6 The frame of every watertight door shall be properly fitted to the bulkhead in which the door is situated, and the jointing material between the frame and the bulkhead shall be of a type that will not deteriorate or be injured by heat.

5.5.7 Every horizontally sliding watertight door shall be so installed as to prevent its moving if the vessel rolls, and if necessary a clip or other suitable device shall be provided for that purpose; the device shall not interfere with the closing of the door when the door is required to be closed.

5.5.8 The means of operation of any watertight door whether power-operated or not shall be capable of closing the door with the ship listed to 15 degrees either side.

5.5.9 Watertight doors shall be fitted with indicators which show at all operating stations from which the doors are not visible whether the doors are open or closed. If any watertight door is not capable of being operated from a central control, means of communication shall be provided whereby the officer of the watch may communicate with the person responsible for the closing of the door.

5.5.10 Hinged doors shall be fitted with quick acting locking devices, operable from each side of the bulkhead.

5.5.11 Hand-operated sliding doors shall have a horizontal motion. It shall be possible to operate the mechanism at the door itself from either side, and, in addition, from an accessible position above the bulkhead deck, with an all round crank motion, or some other movement providing the same guarantee of safety. Departures from this method of operation may be permitted, if this requirement is impossible owing to the layout of the spaces. When operating a hand gear the time necessary for the complete closure of the door with the vessel upright, shall not exceed 90 seconds.

5.5.12 Power operated sliding doors shall have a horizontal motion. If a door is required to be power operated from a central control, the gearing shall be so arranged that the door can be operated by power also at the door itself from both sides. The arrangement shall be such that the door will close automatically if opened by local control after being closed from the central control, and also such that any door can be kept closed by local systems which will prevent the door from being opened from the central control. Local control handles in connection with the power gear shall be provided each side of the bulkhead and shall be so arranged as to enable persons passing through the doorway to hold both handles in the open position without being able to set the closing mechanism in operation accidentally. Power operated sliding doors shall be provided with hand gear workable at the door itself on either side and from an accessible position above the bulkhead deck, with an all round crank motion or some other movement providing the same guarantee of safety. Provision shall be made to give warnings by sound signal that the door has begun to close and will continue to sound until it is completely closed. The door shall take a sufficient time to close to ensure safety.

5.5.13 Where screw gear is used for operating a watertight door, the screw shall work in a part of suitable non-corrodible metal.

5.5.14 Portable plates on bulkheads shall not be permitted except in machinery spaces. Such plates shall always be in place before the vessel leaves port, and shall not be removed during navigation except in case of urgent necessity. The necessary precautions shall be taken in replacing them to ensure that the joints shall be watertight.

5.6.1 The number of side scuttles, scuppers, sanitary discharges and other openings in the shell below the bulkhead deck shall be the minimum compatible with the design and proper working of the vessel.

5.6.2 Side scuttles shall be of a non-opening type and fitted with efficient hinged inside deadlights permanently attached so that they can be readily and effectively closed and secured watertight. The side scuttles, together with their glasses and deadlights, shall be of substantial construction. No side scuttle shall be fitted in a position so that its sill is below a line drawn parallel to the bulkhead deck at side and having its lowest point not less than 500 mm above the maximum load water line. Portable plates instead of deadlights may be provided on vessels operating on home-trade IV and minor waters Class I and II voyages.

5.6.3 All inlets and discharges in the shell plating shall be fitted with efficient and accessible arrangements for preventing the accidental admission of water into the vessel.

5.6.4 Each separate discharge led through the shell plating from spaces below the bulkhead deck shall be provided either with one automatic non-return valve fitted with a positive means of closing it from above the bulkhead deck, or, alternatively, with two automatic non-return valves without such means, the upper of which is so situated above the maximum load water line as to be always accessible for examination under service conditions, and is of a type which is normally closed;

1. where a valve with positive means of closing is fitted, the operating position above the bulkhead deck shall be readily accessible, and means shall be provided for indicating whether the valve is open or closed.

5.6.5 Any valve fitted in compliance with the requirements of subsection 5.6.3 that is a geared valve, or the lower of two non-geared valves, shall be secured to the vessel's shell plating.

5.6.6 All cocks and valves attached to inlets or discharges, or bulkhead fittings within B/5 distance from the shell plating, other than inlets or discharges connected with machinery, being cocks or valves fitted below the bulkhead deck or the failure of which may affect the subdivision of the vessel, shall be made of steel, bronze, or other equally efficient material; if made of steel they shall be protected against corrosion.

5.6.7 Discharge pipes led through the shell plating below the bulkhead deck shall not be fitted in a direct line between the outboard opening and the connection with the deck, water closet, or other similar fittings, but shall be arranged with bends or elbows of substantial metal other than cast iron or lead.

5.6.8 All discharge pipes led through the shell plating below the bulkhead deck and the valves relating thereto shall be protected from damage.

5.6.9 All electronic devices fitted in the bottom shell plating, such as echosounders, speed logs, etc., shall be fitted with efficient and accessible arrangements for preventing admission of water into the vessel.

5.6.10 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.

5.7.1 All doors giving access to the main hull shall be strongly constructed and hung on substantial hinges and locking arrangements shall be such that a door can be opened from either side. The height of the sills of access openings shall be at least 300 mm above the bulkhead deck on vessels operating on home-trade Class III or inland waters Class II voyages, and 150 mm on vessels operating on any other voyages. If portable sills are fitted, they should be properly stowed in a readily accessible position.

5.7.2 Toughened safety glass having a thickness appropriate to the size and position of window, but not less than 6 mm, shall be fitted in wheelhouse windows.

5.7.3 Toughened safety glass or other material having equivalent transparency, strength, surface hardness and shatter safety properties having a thickness appropriate to the size and position of the window, but not less than 6 mm, shall be fitted in all other windows and side scuttles.

5.7.4 In the case of a vessel which operates on home-trade Class III or inland waters Class II voyages, where there is no other means of preventing water from entering the main hull by way of a broken window or side scuttle that is situated above the bulkhead deck, they shall be provided with:

1. storm shutters for windows;
   
   
2. deadlights or portable plates for side scuttles.

5.7.5 Vessels required by these standards to have a one-compartment standard of subdivision shall have all reasonable and practicable measures taken, to limit the entry and spread of water above the bulkhead deck.

5.7.6 Hatchway coamings shall be of substantial construction and shall be at least 450 mm above the deck on vessels operating on home-trade Class III or inland waters Class II voyages, and 300 mm on vessels operating on any other voyages. Hatchways shall be provided with efficient means for battening them down and making them watertight.

5.7.7 Flush deck scuttles shall be watertight and strongly constructed of steel, bronze, aluminum or other equivalent material and shall have effectively secured covers that are retained on hinges or by a chain permanently attached to the ship's structure.

5.7.8 Non-ferrous deck scuttles shall be isolated from the steel structure of the vessel.

5.7.9 In every vessel, side scuttles, gangway ports and other openings in the shell plating above the margin line, and their means of closing, shall be of efficient design and construction and of sufficient strength having regard to the spaces in which they are fitted and their positions relative to the maximum load water line, and to the intended service of the vessel.

5.7.10 In every vessel, the bulkhead deck or a deck above it shall be watertight in the sense that in ordinary sea conditions water will not penetrate in a downward direction. All openings in a watertight deck shall have coamings of adequate height and strength and shall be provided with efficient and rapid means of closing so as to make them watertight; freeing ports or scuppers shall be provided for clearing such deck of water under all weather conditions.

5.7.11 Any funnel or machinery space ventilator that must be kept open for the essential operations of the vessel, and other openings leading below deck or to enclosed superstructure which cannot be closed watertight at sea shall have coamings of adequate height above the bulkhead deck.

5.7.12 Where air pipes extend above the bulkhead or superstructure deck, the height from the deck to the point where water may have access below shall be at least 600 mm on the bulkhead deck and 300 mm on superstructure decks. Satisfactory means, permanently attached, shall be provided for closing the openings of the air pipes.

5.7.13 Ventilators to spaces below bulkhead or superstructure decks shall have coamings substantially constructed, and their height shall be at least 750 mm above the bulkhead deck and 600 mm above the superstructure decks.

5.8.1 Subject to subsections 5.8.2 and 5.8.3, bulwarks, rails, chains, wire rope or any combination of these shall be fitted around the weather deck of the vessel at least 1000 mm in height above the weather deck, and the distance between the rails should be not more than 230 mm, unless strong netting is provided.

5.8.2 An inspector may allow the bulwarks, rails, chains and wire rope referred to in subsection 5.8.1 to be portable at places where they would interfere with the operations of the vessel.

5.8.3 The bulwarks, rails, chains or wire rope referred to in subsection 5.8.1 may be less than 1000 mm in height in areas where passengers have no access.

5.8.4 Subject to subsection 5.8.5 and 5.8.6, where bulwarks fitted on the weather deck of the vessel form wells, the minimum freeing port area, expressed in square meters, in respect of each bulwark shall be not less than

0.7 + 0.035 l

where l, expressed in meters, is the lesser of the length of bulwark in the well or 70 percent of the length of the vessel.

5.8.5 Where the height of the bulwark in a well on the deck is more than 1200 mm, the minimum freeing port area shall be increased, for each 100 mm in excess of 1200 mm, by 0.004 m² per meter of length of the well.

5.8.6 Where the height of the bulwark in a well on the deck is less than 900 mm, the minimum freeing port area may be decreased, for each 100 mm less than 900 mm, by 0.004 m² per meter of length of well.

5.8.7 The freeing ports of every vessel shall be arranged along the length of bulwarks so as to provide rapid and effective freeing of water from the deck of the vessel, and the lower edges of the freeing ports shall be as close to the deck as possible.

5.8.8 Every freeing port over 300 mm in depth shall be fitted with bars spaced not more than 230 mm apart, or with other suitable protective devices.

5.9 Subdivision Letter ^

5.9.1 A letter stating the maximum load draft at which the vessel is permitted to operate will be issued and shall be posted in the wheelhouse, under glass, adjacent to the Inspection Certificate.

6. INTACT AND DAMAGE STABILITY ^

6.1 Stability in Undamaged Condition

6.1.1 The provisions of this section regarding an inclining experiment in the undamaged condition apply to all vessels.

6.1.2 All inclining experiments shall be conducted in the presence of and to the satisfaction of an inspector.

6.1.3 Subject to subsections 6.1.4 and 6.1.5, the inclining experiment requirements of this section shall also apply to vessels which have been:

1. transferred to registry in Canada;
   
   
2. modified or converted in such manner as to affect the vessel's stability.

6.1.4 The inclining experiment may be dispensed with if basic data is available from the inclining experiment of a sister vessel and it is shown to the satisfaction of the Regional Director that reliable stability information can be obtained from such basic data.

6.1.5 The Regional Director may allow the inclining experiment to be dispensed with in exceptional circumstances if it can be shown to the Regional Director's satisfaction that owing to the form, construction and arrangement of the vessel, stability calculations can safely be made without the inclining experiment being conducted.

6.1.6 Subject to subsection 6.1.7 the results obtained from an inclining experiment referred to in subsection 6.1.2 shall be developed in accordance with the requirements of the "Stability, Subdivision, and Load Line Standards", TP 7301E to indicate the stability of the vessel in the following conditions:

1. lightship;
   
   
2. light operating condition;
   
   
3. departure condition;
   
   
4. arrival condition;
   
   
5. worst designed operating condition that will be experienced having regard to the service in which the vessel will be engaged.

6.1.7 For vessels operating on voyages other than home-trade III and inland waters Class II, superstructures and deckhouses not regarded as enclosed can be taken into account in stability calculations up to the angle at which their openings are flooded (at this angle, the static stability curve should show one or more steps, and in subsequent computations the flooded space should be considered non-existent).

6.1.8 The owner of a vessel shall provide a document to be placed on board the vessel, containing the results of the inclining experiment required by subsection 6.1.2 and other relevant information for the use of the master, and it shall be the responsibility of the owner and master to ensure that a proper measure of stability is maintained for all conditions of loading and ballasting. In general, this information shall contain:

1. stability characteristics of the vessel;
   
   
2. appropriate information relative to loading conditions specified in this section;
   
   
3. any operating condition that shall be maintained to assure the safety of the vessel.

6.2 Stability in Damaged Condition ^

6.2.1 This section applies to every vessel carrying more than 12 berthed passengers on any voyage, and vessels carrying more than 50 unberthed passengers on home-trade Class III or inland waters Class II voyages.

6.2.2 Every vessel shall be so constructed so as to provide sufficient intact stability in all service conditions to enable the vessel to withstand the final flooding of any one of the main compartments into which the vessel is subdivided.

6.2.3 Every vessel shall be so constructed as to keep unsymmetrical flooding to the minimum when the vessel is in a damaged condition.

6.2.4 For the purposes of this section, the sufficiency of the stability of every such vessel shall be determined in accordance with the provisions of the "Ship Safety Passenger Ship Operations and Damaged Stability Standards (Non-convention Ships)" TP10943E, with the exception that the minimum assumed longitudinal extent of damage may be 10 per cent of the maximum load water line length.

6.2.5 Relaxations from the requirements for damage stability shall be permitted only in exceptional cases and subject to the condition that the Board is to be satisfied that the proportions, arrangements and other characteristics of the vessel are the most favorable to stability after damage which can practically and reasonably be adopted in the particular circumstances.

6.2.6 No relaxation from the requirements for damage stability may be considered by the Board unless it is shown that the intact metacentric height in any service condition necessary to meet these requirements is excessive for the service intended.

6.3 Survivability Criteria ^

6.3.1 This section applies to vessels carrying not more than 12 berthed passengers or not more than 100 unberthed passengers on home-trade Class IV, minor waters Class I or II voyages, or not more than 50 unberthed passengers on home-trade Class III or inland waters Class II voyages.

6.3.2 The stability of every vessel shall be deemed to be sufficient, if the calculation shows that, after the assumed damage, the final condition of the vessel is as follows:

1. in the event of symmetrical flooding, the metacentric height is positive, but not less than 0.05 meter;
   
   
2. in the event of unsymmetrical flooding, the heel does not exceed seven degrees; and
   
   
3. the bulkhead deck is not submerged.

6.4 Stability in Swamped Condition ^

6.4.1 This section applies to all vessels which may be subject to swamping.

6.4.2 The stability of the swamped vessel shall be deemed to be sufficient, if the calculation shows that, after open wells or cockpits have been flooded, the final condition of the vessel is as follows:

1. the metacentric height is positive, but not less than 0.05 meter, and
   
   
2. the minimum freeboard to the top of the well or cockpit is 150 mm.

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