The following criteria are recommended for passenger and cargo ships.
- The area under the righting lever curve (GZ curve) should not be less than 0.055 metre-radian up to e = 30° angle of heel and not less than 0.09 metre-radian up to 9 = 40° or the angle of flooding θf if this angle is less than 40°. Additionally, the area under the righting lever curve (GZ curve) between the angles of heel of 30° and 40° or between 30° and θf , if this angle is less than 40°, should not be less than 0.03 metre-radian.
- The righting lever GZ should be at least 0.20 m at an angle of heel equal to or greater than 30°.
- The maximum righting arm should occur at an angle of heel preferably exceeding 30° but not less than 25°.
- The initial metacentric height GMo should not be less than 0.15
- In addition, for passenger ships, the angle of heel on account of crowding of passengers to one side as defined should not exceed 10 degree.
- Where anti-rolling devices are installed in a ship, the Administration should be satisfied that the above criteria can be maintained when the devices are in operation.
- In addition, for passenger ships, the angle of heel on account of turning should not exceed 10 degree when calculated using the following formula.
