Directive 2009/45/EC of the European Parliament and of the CouncilShow full title

NEW CLASS B, C AND D SHIPS AND EXISTING CLASS B RO-RO PASSENGER SHIPS AND EXISTING CLASS B NON RO-RO PASSENGER SHIPS, CONSTRUCTED ON OR AFTER 29 APRIL 1990:

.2.3 The stability required in the final condition after damage, and after equalisation where provided, shall be determined as follows:

.2.3.1

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 cases where the area under the righting lever curve is that specified in subparagraph .2.3.2 multiplied by the ratio 15/range, where range is expressed in degrees.

.2.3.2

The area under the righting lever curve shall be at least 0,015 m-rad, measured from the angle of equilibrium to the lesser of:

.1

the angle at which progressive flooding occurs;

.2

22 ° (measured from upright) in the case of one-compartment flooding, or 27 ° (measured from the upright) in the case of the simultaneous flooding of two adjacent compartments.

.2.3.3

A residual righting lever is to be obtained within the range of positive stability, taking into account the greatest of the following heeling moments:

.1

the crowding of all passengers towards one side;

.2

the launching of all fully loaded davit-launched survival craft on one side;

.3

due to wind pressure;

as calculated by the formula:

However, in no case is the righting lever to be less than 0,10 metres.

.2.3.4

For the purpose of calculating the heeling moments in paragraph .2.3.3 the following assumptions shall be made:

.1

Moment due to crowding of passengers:

.1.1

four persons per square metre;

.1.2

a mass of 75 kg for each passenger;

.1.3

passengers shall be distributed on available deck areas towards one side of the ship on the decks where assembly stations are located and in such a way that they produce the most adverse heeling moment.

.2

Moment due to launching of all fully loaded davit-launched survival craft on one side:

.2.1

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;

.2.2

for lifeboats which are arranged to be launched fully loaded from the stowed position, the maximum heeling moment during launching shall be taken;

.2.3

a fully loaded davit-launched life-raft 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;

.2.4

persons not in the life-saving appliances which are swung out shall not provide either additional heeling or righting moment;

.2.5

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.

.3

Moments due to wind pressure:

.3.1

class B: a wind pressure of 120 N/m² to be applied;

classes C and D: a wind pressure of 80 N/m² to be applied;

.3.2

the area applicable shall be the projected lateral area of the ship above the waterline corresponding to the intact condition;

.3.3

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.

.2.4 When major progressive flooding occurs, that is, when it causes a rapid reduction in the righting lever of 0,04 metres or more, the righting lever curve is to be considered as terminated at the angle the progressive flooding occurs and the range and the area referred to in .2.3.1 and .2.3.2 should be measured to that angle.

.2.5 In cases where the progressive flooding is of limited nature that does not continue unabated and causes an acceptably slow reduction in righting lever of less than 0,04 metres, the remainder of the curve shall be partially truncated by assuming that the progressively flooded space is so flooded from the beginning.

.2.6 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.