- Laws of Fiji

[MAT 42,800] Subdivision and stability160

160

(1) The owner of any new ship which is an oil tanker shall ensure that it complies with—

(a)the subdivision and damage stability criteria specified in subregulation (3); and
(b)the assumed side or bottom damage specified in subregulation (2), at any operating draught reflecting actual, partial or full load conditions consistent with the trim and strength of the ship as well as the specific gravities of the cargo and such damage shall be applied to all conceivable locations along the length of the ships as follows—
- (i)in any tanker of more than 225 metres in length, anywhere in the ship’s length;
- (ii)in any tanker of more than 150 metres, but not exceeding 225 metres in length, anywhere in the ship’s length except involving either after or forward bulkhead bounding the machinery space located aft and the machinery space is treated as a single floodable compartment; and
- (iii)in any tanker not exceeding 150 metres in length, anywhere in the ship’s length between adjacent transverse bulkheads with the exception of the machinery space. Ballast conditions where the tanker is not carrying oil in cargo tanks, excluding any oil residues, shall not be taken into account.

(2) The following provisions, regarding the extent and the character of the assumed damage shall be applied—

(a)	side damage
	(i)	longitudinal extent:	1/3(L^2/3) or 14.5 metres, whichever is less
	(ii)	transverse extent (inboard from the ship’s side at right angles to the centre-line at the level of the summer load line)	B/5 or 11.5 metres, whichever is less
	(iii)	vertical extent	From the moulded line of the bottom shell plating at centreline, upward without limit

(b)	bottom damage		For 0.3L from the forward perpendicular of the ship	Any other part of the ship
	(i)	longitudinal extent:	1/3(L^2/3) or 14.5 metres, whichever is less	1/3(L^2/3) or 5 metres, whichever is less
	(ii)	transverse extent:	B/6 or 10 metres whichever is less	B/6 or 5 metres whichever is less
	(iii)	vertical extent:	B/15 or 6 metres, whichever is less, measured from the moulded line of the bottom shell plating at centerline	B/15 or 6 metres, whichever is less, measured from the moulded line of the bottom shell plating at centerline

(c)if any damage of a lesser extent than the maximum extent specified in subregulations (2)(a) and (b) would result in a more severe condition, such damage is to be taken in account;
(d)where the damage involving transverse bulkheads is envisaged as specified in subregulations (1)(a) and (b), transverse watertight bulkheads shall be spaced at least at a distance equal to the longitudinal extent of assumed damage specified in subregulations (2)(a)(i) in order to be considered effective and where transverse bulkheads are spaced at lesser distance, one or more of these bulkheads within such extent of damage shall be assumed non-existent for the purpose of determining flooded compartments;
(e)where the damage between adjacent transverse watertight bulkheads is envisaged as specified in subregulations (1)(c), no main transverse bulkhead or a transverse bulkhead bounding side tanks or double bottom tanks is assumed to be damaged, unless—
- (i)the spacing of the adjacent bulkheads is less than the longitudinal extent of assumed damage specified in subregulations (2)(a)(i); or
- (ii)there is a step or recess in a transverse bulkhead or more than 3.05 metres in length, located within the extent or penetration of assumed damage. The step formed by the after peak bulkhead and after peak tank top shall not be regarded as a step for the purpose of this Division; and
(f)if pipes, duct or tunnels are situated within the assumed extent of damage, arrangements shall be made so that progressive flooding cannot extend to compartments other than those assumed to be floodable for each case of damage.

(3) Subject to subregulation (4), an oil tanker shall be regarded as complying with the damage stability criteria if the following requirements are met—

(a)the final waterlines, taking into account sinkage, heel and trim, is below the lower edge of any opening through which progressive flooding can take place where such openings include air pipes and those which are closed by means of weathertight doors or hatch covers and excludes those openings closed by means of watertight manhole covers and flush scuttles, small watertight cargo tank hatch covers which maintain the high integrity of the deck, remotely operated watertight sliding doors, and side scuttles of the non-opening type;
(b)in the final stage of flooding, the angle of heel due to unsymmetrical flooding does not exceed 25 degrees and this angle may be increased up to 30 degrees if deck edge immersion does not occur;
(c)in the final stage of flooding the righting lever curve has at least a range of 20 degrees beyond the position of equilibrium in association with a maximum residual righting lever of at least 0.1 metre within the 20 degrees range and the area under curve within this range is not less than 0.0175 metre radians. Unprotected opening shall not be immersed within this range unless the space concerned is assumed to be flooded. The immersion of any of the openings listed in paragraph (a) and other openings capable of being closed weathertight may be permitted within this range; and
(d)the surveyor before approving the stability calculations for the ship for the purposes of the initial survey as required by regulations 91(2)(a) is satisfied that the stability is sufficient during intermediate stages of flooding.

(4) Equalisation arrangements requiring mechanical aids such as valves or cross levelling pipes, if fitted, shall not be considered for the purpose of reducing an angle of heel or attaining the minimum range of residual stability to meet the requirements of subregulations (3)(a), (b) and (c), and sufficient residual stability shall be maintained during all stages where equalisation is used. Spaces which are linked by ducts of a large cross-sectional area may be considered to be common.

(5) For tankers of 100 metres or less in length where all the requirements of subregulation (3) cannot be fulfilled without impairing the operation of the ship, an exemption may be granted in accordance with section 33 of the Act.

(6) The surveyor undertaking the initial survey required by regulation 91(2)(a) shall be satisfied that the requirements of subregulation (1) have been complied with by means of calculations which take into consideration the design characteristics of the ship, the arrangements, configuration and contents of the damaged compartments; and the distribution, specific gravities and the free surface effect of liquids. The calculations shall be based on the following—

(a)account shall be taken of any empty or partially filled tank, the specific gravity of cargoes carried, as well as any outflow of liquids from damaged compartments;
(b)the permeability assumed for spaces flooded as a result of damage shall be as follows—
Spaces Permeability
Appropriated to stores 0.60
Occupied by accommodation 0.95
Occupied by machinery 0.85
Voids 0.95
Intended for consumable liquids 0 to 0.95*
Intended for other liquids 0 to 0.95*
* The permeability of partially filled compartments shall be consistent with the amount of liquid carried in the compartment. Whenever damage penetrates a tank containing liquids, it shall be assumed that the contents are completely lost from that compartment and replaced by salt water up to the level of the final plane of equilibrium;
(c)the buoyancy of any superstructure directly above the side damaged shall be disregarded. The unflooded parts of superstructures beyond the extent of damage, however, may be taken into consideration provided that they are separated from the damaged space by watertight bulkheads and the requirements of subregulations (3)(a) in respect of these intact spaces are complied with. Hinged watertight doors may be acceptable in watertight bulkheads in the superstructure;
(d)the free surface effect is calculated at an angle of heel of 5 degrees for each individual compartment. The Chief Executive Officer may require or allow the free surface corrections to be calculated at an angle of heel greater than 5 degrees for partially filled tanks; and
(e)in calculating the effect of free surfaces of consumable liquids it is assumed that, for each type of liquid at least one transverse pair or a single centreline tank has a free surface and the tank or combination of tanks to be taken into account are those where the effect of free surfaces is the greatest.

	Spaces	Permeability
	Appropriated to stores	0.60
	Occupied by accommodation	0.95
	Occupied by machinery	0.85
	Voids	0.95
	Intended for consumable liquids	0 to 0.95*
	Intended for other liquids	0 to 0.95*

(7) The owner of any new oil tanker or any new non-self-propelled oil tanker to which this part applies, shall supply, in an approved form, to the master or to the person in charge of that tanker—

(a)information relating to loading and distribution of cargo necessary to ensure compliance with the provisions of regulation 160; and
(b)data on the ability of the ship to comply with damage stability criteria as determined by regulation 160, including the effect of reductions that may have been allowed under subregulation (2)(c).