A performance-based survivability assessment of regulatory frameworks

Deterministic regulatory frameworks of the past could only provide information of whether a vessel could comply with a pre-determined set of criteria but failed to provide information on the level of safety pertinent to a specific design. Probabilistic frameworks by definition can provide such sort of information, necessary for comparison in an optimisation process. SOLAS 2009, as a probabilistic framework, entails this capability but failed to inspire confidence in the maritime industry due to a series of misconceptions and inherent drawbacks in its formulation and application. The latest developments in survivability assessment have provided the ability to measure the survivability of any design, irrespective of which standard it is developed to comply with. To this end, this paper is aimed at conducting a direct comparison of probabilistic and deterministic regulatory frameworks for damage stability on a selection of Ro-Ro passenger vessels of various sizes. Both numerical and analytical performance-based assessment methods will be utilised, highlighting in the process any inherent inconsistencies in each framework, in an attempt to restore confidence in state-of-the-art on damage stability assessment. Specific attention is to be paid to the controversial design feature of the long lower hold.