Stability information
22.—(1)  (a)  A new ship which is 24 metres in length or more shall be inclined upon its completion and the elements of its stability determined.
(b)  The ship shall satisfy the following minimum stability criteria unless the Director is satisfied that the area in which the ship operates justifies departure therefrom:
(i)the area under the righting lever curve (GZ curve) shall not be less than 0.055 metre-radians up to 30 degrees angle of heel and not less than 0.090 metre-radians up to 40 degrees or the angle of flooding (θf) if this angle is less than 40 degrees. In addition, the area under the righting lever curve (GZ curve) between the angles of heel of 30 degrees and 40 degrees or between 30 degrees and θf, if this angle is less than 40 degrees, shall not be less than 0.030 metre-radians. θf is the angle of heel at which openings in the hull, superstructure or deckhouses which cannot be rapidly closed water-tight commence to immerse. In applying this criterion, small openings through which progressive flooding cannot take place need not be considered as open;
(ii)the righting lever GZ shall be at least 200 millimetres at an angle of heel equal to or greater than 30 degrees;
(iii)the maximum righting lever GZmax shall occur at an angle of heel preferably exceeding 30 degrees but not less than 25 degrees;
(iv)the initial metacentric height GM shall not be less than 150 millimetres.
(c)  Where arrangements other than bilge keels are provided to limit the angles of roll, the Director shall be satisfied that the stability referred to in paragraph (b) is maintained in all operating conditions.
(d)  Where ballast is provided to ensure compliance with paragraph (b), its nature and arrangement shall be to the satisfaction of the Director.
(2)  In the case of a new ship which is less than 24 metres in length a stability test shall be conducted with weights to represent the fully laden service condition. The weight of each passenger shall be taken as 65 kilogrammes. In the test the heel of the ship caused by a heeling moment equal to the weight of the passengers multiplied by the extreme breadth of the ship, shall not be more than 7 degrees. A copy of the results of the stability test shall be submitted to the Director.
(3)  Where an alteration is made to a ship so as to materially affect its stability, amended or new stability information shall be submitted to the Director.
(4)  The Director may allow the inclining test of a ship to be dispensed with where —
(a)basic stability data are available from the inclining test of a sister ship; and
(b)it is shown to the satisfaction of the Director that reliable stability information for that ship can be obtained from such basic data.