The IMO sub-committee on Ship Design and Construction developed the Second Generation Intact Stability Criteria (SGISC) to upgrade ship safety at sea assessment, accounting for unconventional hulls, reduction of installed power and larger cruise and container vessels. The SGISC address five dynamic stability failure modes: parametric roll, pure loss of stability, broaching, dead ship and excessive acceleration, which must be assessed using a three-tier approach.
CRS DYNASTY focused on parametric roll, loss of stability and dead ship, and evaluated Direct Stability Assessment Levels 1 and 2 against model tests. Environmental conditions and key simulation parameters were evaluated to perform DSA Level 3. Model tests were conducted to establish the influence of parameters such as wave height and ship loading condition, on the occurrence of failure modes and to obtain validation data for numerical simulations.
Good agreement is obtained for some cases of parametric roll and pure loss of stability; other cases show discrepancies between simulations and experiments and even among participants. We need consensus on how potential flow should be applied for stability assessment. Further research into roll damping is needed, as this is key to a reliable prediction of stability failure.