1 In addition to the requirements of SOLAS regulation II–1/8, ro-ro passenger ships shall comply, subject to the provisions of paragraph 2, if applicable, with the following:

.1. the provisions of paragraphs 2.3 regulation 8 shall be complied with when taking into account the effect of a hypothetical amount of sea water which is assumed to have accumulated, on the first deck above the designed waterline of the ro-ro cargo space or special category space as defined in regulation II–2/3 assumed to be damaged (referred to as “the damaged ro-ro deck" hereinafter). The other requirements of regulation 8 need not be complied with in the application of the stability standard

1) Guidance notes on the standard to be developed.

contained in this Agreement. The amount of assumed accumulated sea water shall be calculated on the basis of a water surface having a fixed height above:

a) the lowest point of the deck edge of the damaged compartment of the ro-ro deck, or

b) when the deck edge in way of the damaged compartment is submerged then the calculation is based on a fixed height above the still water surface at all heel and trim angels;

as follows:

0.5 m if the residual freeboard fr) is 0.3 m or less;

0.0 m if the residual freeboard (fr) is 2.0 m or more; and intermediate values to be determined by linear interpolation, if the residual freeboard (fr) is 0.3 m or more but less than 2.0 m; where the residual freeboard (fr) is the minimum distance between the damaged ro-ro deck and the final waterline at the location of the damage in the damage case being considered without taking into account the effect of the volume of assumed accumulated water on the damaged ro-ro deck;

.2. when a high-efficiency drainage system is installed, the Administration may allow a reduction in the height of the water surface in accordance with the guidelines to be developed by the Organization

1) Refer to the “guidelines ..... ".

;

.3. for ships in geographically defined restricted areas of operation, the Administration may reduce the height of the water surface determined in accordance with subparagraph 1 substituting such height of the water surface by the following:

.3.1. 0.0 m if the significant wave height (hs) defining the area concerned is 1.5 m or less;

.3.2. the value determined in accordance with subparagraph 1 if the significant wave height (hs) defining the area concerned is 4.0 m or above;

.3.3. intermediate values to be determined by linear interpolation if the significant wave height (hs) defining the area concerned is 1.5 m or more but less than 4.0 m;

provided that the following conditions are fulfilled:

.3.4. the Administration is satisfied that the defined area is represented by the significant wave height (hs) which is not exceeded with a probability of more than 10%; and

.3.5. the area of operation and, if applicable, the part of the year for which a certain value of the significant wave height (hs) has been established are entered into the certificates; and

.4. as an alternative to the requirements of subparagraph .1 or sub- paragraph .3, the Administration may exempt application of the requirements of subparagraph .1 or subparagraph .3 and accept proof, established by model tests carried out for an individual ship in accordance with the model test method developed by the Organization

1) Refer to the “model test method attached to this document".

, annexed to this document justifying that the ship will not capsize with the assumed extent of damage as provided in paragraph 4 of regulation 8 in the worst location being considered under paragraph 1.1 in an irregular seaway, and

.5. reference to acceptance of the results of the model test as an equivalence to compliance with subparagraph .1 or subparagraph .3; the value of the significant wave height (hs) used in the model tests shall be entered into the ship's certificates.

.6. the information supplied to the master in accordance with paragraphs 7.1 and 7.2 of regulation 8, as developed for compliance with paragraphs 2.3 to 2.3.4, shall apply unchanged for ro-ro passenger ships approved according to these requirements.

2 For assessing the effect of the volume of the assumed accumulated sea water on the damaged ro-ro deck in paragraph 1, the following provisions shall prevail:

.1. a transverse or longitudinal bulkhead shall be considered intact if all parts of it lie inboard of vertical surfaces on both sides of the ship, which are situated at a distance from the shell plating equal to one-fifth of the breadth of the ship, as defined in regulation 2, and measured at right angles to the centreline at the level of the deepest subdivision load line;

.2. in cases where the ship's hull is structurally partly widened for compliance with the provisions of this regulation, the resulting increase of the value of one-fifth of the breadth of it is to be used throughout, but shall not govern the location of existing bulkhead penetrations, piping systems, etc., which were acceptable prior to the widening;

.3. the tightness of transverse or longitudinal bulkheads which are taken into account as effective to confine the assumed accumulated sea water in the compartment concerned in the damaged ro-ro deck shall be commensurate with the drainage system, and shall withstand hydrostatic pressure in accordance with the results of the damage calculation. Such bulkheads shall be at least 4 m in height unless the height of water is less than 0.5 m. In such cases the height of the bulkhead may be calculated in accordance with the following:

Bh = 8hw

where Bh = bulkhead height, and

hw = height of water

In any event,the minimum height of the bulkhead shall be not less than 2.2 m. However, in the case of a ship with hanging car decks, the minimum height of the bulkhead shall be not less than the height to the underside of the hanging car deck when in its lowered position.

.4. For special arrangements such as, e.g., full width hanging decks and wide side casings, other bulkhead heights may be accepted based on detailed model tests;

.5. The effect of the volume of the assumed accumulated sea water need not be taken into account for any compartment of the damaged ro-ro deck, provided that such a compartment has on each side of the deck freeing ports evenly distributed along the sides of the compartment complying with the following:

.5.1. A ≥ 0.3 l

where A is the total area of freeing ports on each side of the deck in m2; and

I is the length of the compartment in m;

.5.2. the ship shall maintain a residual freeboard of at least 1.0 m in the worst damage condition without taking into account the effect of the assumed volume of water on the damaged ro-ro deck; and

.5.3. such freeing ports shall be located within the height of 0.6 m above the damaged ro-ro deck, and the lower edge of the ports shall be within 2 cm above the damaged ro-ro deck; and

.5.4. such freeing ports shall be fitted with closing devices or flaps to prevent water entering the ro-ro deck whilst allowing water which may accumulate on the ro-ro deck to drain; and

.6. when a bulkhead above the ro-ro deck is assumed damaged, both compartments bordering the bulkhead shall be assumed flooded to the same height of water surface as calculated in paragraphs 1.1 and 1.3 above.