Section 36
Stability of passenger ships in damaged condition.*
of Merchant Shipping (Safety Convention) Regulations, 2003
(1)
Subject to regulation 37, paragraphs (c) and (d) of sub-regulation (3), sub-regulation (6) and paragraph (b) of sub-regulation (7) apply to passenger ships constructed on or after 29th. Apri1 1 1990.
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(2)
(a} Sufficient intact stability shall be provided in all service conditions so as to enable the ship to withstand the final stage of flooding of any one main compartment which is required to be within the floodable length.
(b)
Where 2 adjacent main compartments are separated by a bulkhead which is stepped un'der the conditions of paragraph (a} of sub-regulation (5) of regulation 35, the intact stability shall be adequate to with-stand the flooding of those 2 adjacent main compartments.
* Refer to MSC/Circ.541 (as may be revised): Guidance Notes on the Integrity of Flooding Boundaries above the Bulkhead Deck of Passenger Ships for proper application of regulations 36 and 54(1).
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551 27th. DECEMBER, 2003
{c}
Where the required factor of subdivision is 0.50 or less but more than 0.33, the intact stability shall be adequate to withstand the flooding of any 2 adjacent main compartments.
{dj Where the required factor of subdivision is 0.33 or less, the intact stability shall be adequate to withstand the flooding of any 3 adjacent main compartments.
(3)
(a} The requirements of sub-regulation
(2)
shall be deter-mined by calculations which are in accordance with sub-regulations (4), (5)
and (7) and which take into consideration the proportions and design characteristics of the ship and the arrangement and configuration of the damaged compartments. In making these calculations the ship is to be assumed in the worst anticipated service condition as regards stability.
(b}
Where it is proposed to fit decks, inner skins or longitudinal bulk-heads of sufficient tightness to seriously restr~t the flow of water, proper consideration shall be given to such restrictions in the calculations.
(c}
The stability required in the final condition after damage, and after equalisation where provided, shall be determined as follows -
(i)
the positive residual righting lever curve shall have a minimum range of 15° beyond the angle of equilibrium. This range may be reduced to a minimum of 10°, in the case where the area under the righting lever curve is that specified in sub-paragraph (ii). increased by the ratio-
15
Range where the range is expressed in degrees;
(ii)
the area under the righting lever curve shall be at least 0.015
metre-radians, measured from the angle of equilibrium to the lesser of-lA) the angle at which progressive flooding occurs;
(B)
22° (measured from the upright) in the case of one-compartment flooding, or 27° (measured from the upright) in the case of the simultaneous flooding of 2 or more adjacent compartments;
BRUNEI DARUSSALAM GOVERNMENT GAZETTE jiii)
a residual righting lever is to be obtained within the range of positive stability, taking into account the greatest of the following heeling moments -
jA)
the crowding of all passengers towards one side;
(BJ the launching of all fully loaded davit-launched survival craft on one side;
(CJ due to wind pressure;
as calculated by the formula -
heeling moment
GZ (in metres)
------- + 0.04
displacement
However, in no case is this righting lever to be less than 0.1
metre;
jivJ for the purpose of calculating the heeling moments in sub-paragraph (iii), the following assumptions shall be made -
jA)
moments due to crowding of passengers -
(I)
4 persons per square metre;
(II)
a mass of 75 kg for each passenger;
(III)
passengers shall be distributed on available deck areas towards one side of the ship on the decks
.• where muster stations are located and in such a way that they produce the most adverse heeling moment;
(B)
moments due to launching of all fully loaded davit-launched survival craft on one side
(I)
all lifeboats and rescue boats fitted on the side to which the ship has heeled after having sustained damage shall be assumed to be swung out fully loaded and ready for lowering;
(II)
for lifeboats which are arranged to be launched fully loaded from the stowed position, the maximum heeling moment during launching shall be taken;
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27th. DECEMBER 1 2003
(III)
a fully loaded davit-launched liferaft attached to each davit on the side to which the ship has heeled after having sustained damage shall be assumed to be swung out ready for lowering;
(IV)
persons not in the life-saving appliances which are swung out shall not provide either additional heeling or righting moment;
(V)
life-saving appliances on the side of the ship opposite to the side to which the ship has heeled shall be assumed to be in a stowed position;
(CJ moments due to wind pressure -
(I)
a wind pressure of 120 N/m2 to be applied;
,-
(II)
the area applicable shall be the projected lateral area of the ship above the water-line corresponding to the intact condition;
(III)
the moment arm shall be the vertical distance from a point at one-half of the mean draught corresponding to the intact condition to the centre of gravity of the lateral area.
In intermediate stages of flooding, the maximum righting lever shall be at least 0.05 metres and the range of positive righting levers shall be at least 7°. In all cases, only one breach in the hull and only one free surface need be assumed.
(4)
(aJ
For the purpose of making damage stability calculations, the volume and surface permeabilities shall be, in general, as follows
Spaces
Appropriated to cargo, coal or stores
Occupied by accommodation
Occupied by machinery
Intended for liquids
* Whichever results in the more severe requirements.
553
Permeability
60 95 85 0 or 95*
__J
(b)
Higher surface permeabilities are to be assumed in respect of spaces which, in the vicinity of the damage waterplane, contain no sub-stantial quantity of accommodation or machinery and spaces which are not generally occupied by any substantial quantity of cargo or stores.
iS)
Assumed extent of damage shall be as follows-
{a)
longitudinal extent: 3 metres plus 3% of the length of the ship, or 11 metres, whichever is the less; and where the required factor of sub-division is 0.33 or less, the assumed longitudinal extent of damage shall be increased as necessary so as to include any 2 consecutive main transverse watertight bulkheads;
(b)
transverse extent !measured inboard from the ship's side, at right angles to the centreline at the level of the deepest subdivision load line): a distance of one-fifth of the breadth of the ship;
{c)
vertical extent: from the base line upwards without limit; and
{d) if any damage of lesser extent than that indicated in paragraphs
(a)
, {b) and {c) would result in a more severe condition regarding heel or loss of metacentric height, such damage shall be assumed in the calculations.
(6)
Unsymmetrical flooding is to be kept to a minimum consistent with efficient arrangements. Where it is necessary to correct large angles of heel, the means adopted shall, where practicable, be self-acting, but in any case where controls to cross-flooding fittings are provided they shall be operable from above the bulkhead deck. These fittings together with their controls shall be acceptable to the Director. The maximum angle of heel after flooding but before equalisation shall not exceed 15°. Where cross-flooding fittings are required, the time for equalisation shall not exceed 15 minutes. Suitable information concerning the use of cross-flooding fittings shall ge supplied to the master of the ship.*
(7)
The final conditions of the ship after damage and, in the case of unsymmetrical flooding, after equalisation measures have been taken shall be as follows-
(a)
in the case of symmetrical flooding, there shall be a positive residual metacentric height of at least 50 millimetres as calculated by the constant displacement method;
* Reference is made to the Recommendation on a Standard Method for Establishing Compliance with the requirements for Cross-Flooding Arrangements in Passenger Ships, adopted by the Organisation by resolution A.226(VIII).
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555 27th. DECEMBER, 2003
{b)
in the case of unsymmetrical flooding, the angle of heel for one-compartment flooding shall not exceed 7°; for the simultaneous flooding of 2 or more adjacent compartments, a heel of 12° may be permitted by the
Director;
{c)
in no case shall the margin line be submerged in the fmal stage of flooding; if it is considered that the margin line may become submerged during an intermediate state of flooding, the Director may require such investigations and arrangements as he considers necessary for the safety of the ship.
(8)
fa) The master of the ship shall be supplied with the data necessary to maintain sufficient intact stability under service conditions to enable the ship to withstand the critical damage. In the case of ships requiring cross-flooding, the master of the ship shall be informed of the conditions of stability on which the calculations of heel are based and be warned that excessive heeling might result should the ship .sustain damage when in a less favourable condition.
(b)
The data referred to in paragraph {a}, to enable the master to maintain sufficient intact stability, shall include information which indicates the maximum permissible height of the ship's centre of gravity above keel (KGL or alternatively the minimum permissible metacentric height (GMJ for a range of draughts or displacements sufficient to include all service conditions. The information shall show the influence of various trims taking into account the operational limits.
{c)
Each ship shall have scales of draughts marked clearly at the bow and stern. In the case where the draught marks are not located where they are easily readable, or operational constraints for a particular trade make it difficult to read the draught marks, then the ship shall also be fitted with a reliable draught indicating system by which the bow and stern draughts can be determined.
{d)
On completion of loading of the ship and prior to its departure, the master shall determine the ship's trim and stability and also ascertain and record that the ship is in compliance with stability criteria in relevant regulations. The determination of the ship's stability shall always be made by calculation. The Director may accept the use of an electronic loading and stability computer or equivalent means for this purpose.
(e)
Paragraphs {b), {c) and (d) apply to all passenger ships.
(9)
{a)
No relaxation from the requirements for damage stability may be considered by the Director unless it is shown that the intact metacentric height in any service condition necessary to meet these requirements is excessive for the service intended.
(b)
Relaxations from the requirements for damage stability shall be permitted only in exceptional cases and subject to the condition that the Director is satisfied that the proportions, arrangements and other characteristics of the ship are the most favourable to stability after damage which can practically and reasonably be adopted in the particular circumstances.