11.3 Damage Stability

 The following requirements are applicable to all vessels, other than those operating as Short Range Yachts. Whilst Short Range Yachts are not required to meet the damage stability criteria defined above, ultimate survivability after minor damage or flooding is recommended.

It should be noted that compliance with the damage stability criteria is not required for vessels that obtain full compliance with the ICLL conditions of assignment.

  11.3.1 The watertight bulkheads of the vessel should be so arranged that minor hull damage that results in the free flooding of any one compartment, will cause the vessel to float at a waterline which, at any point, is not less than 75mm below the weather deck, or bulkhead deck if not concurrent.

  11.3.2 Minor damage should be assumed to occur anywhere in the length of the vessel, but not on a watertight bulkhead.

  11.3.3 Standard permeabilities should be used in this assessment, as follows:

  11.3.4 In the damaged condition, considered in 11.3.1, the residual stability should be such that any angle of equilibrium does not exceed 7° from the upright, the resulting righting lever curve has a range to the downflooding angle of at least 15° beyond any angle of equilibrium, the maximum righting lever within that range is not less than 100mm and the area under the curve is not less than 0.015 metre radians.

Notes:

1 Range of stability in “damaged” condition shall have regard, where appropriate, to truncation due to downflooding.

2 The required properties of the “damaged” GZ curve, namely max. GZ ≥ 0.1m and the area under the curve of ≥ 0.015m rads. is to be achieved within the positive range of the curve taking into account any restrictions imposed by Note 1.

  11.3.5 A vessel of 85 metres length and above should meet a SOLAS 90 passenger ship one-compartment standard of subdivision, calculated using the deterministic damage stability methodology.