The paper provides a full description and explanation of the probabilistic method for ship damage stability assessment from its conception to date with focus on the probability of survival (s-factor), explaining pertinent assumptions and limitations and describing its evolution for specific application to passenger ships, using contemporary numerical and experimental tools and data. It also provides comparisons in results between statistical and direct approaches and makes recommendations on how these can be reconciled with better understanding of the implicit assumptions in the approach for use in ship design and operation. Evolution over the latter years to support pertinent regulatory developments relating to flooding risk (safety level) assessment as well as research in this direction with a focus on passenger ships, have created a new focus that combines all flooding hazards (collision, bottom and side groundings) to assess potential loss of life as a means of guiding further research and developments on damage stability for this ship type. The paper concludes by providing recommendations on the way forward for ship damage stability and flooding risk assessment.

SOLAS2020 damage stability regulations are based on probabilistic damage distributions. Those originate from the pooled analysis of collision accidents across a fleet with bias towards cargo ships. This paper introduces a method that accounts for collision-based crashworthiness on ship damage distributions. The method reshapes statistical SOLAS damage distributions for a given ship or structural details for a reference ship section and her reinforced version. Damage reductions may differ depending on ship characteristics and operational scenarios. To mitigate this, a high number of collision scenarios was simulated using the super-element method. It is shown that risk control in terms of damage reduction over the whole range of damages is possible by adding a double hull or by deck reinforcement. Damage reduction is quantified by damage stability analysis of a cruise vessel. It is concluded that installing a double hull on ship vulnerable zones leads to increased A-index.

Dynamics of damaged ships has repelled close attention until the 1980s, following ground shaking accidents (Herald of Free Enterprise, 1987 and Estonia, 1994). Research since then continues unabated, in the knowledge that damage stability is responsible for 90% of deaths in the maritime industry. Notwithstanding this, safety even in the most advanced maritime nations is still being perceived as unnecessary burden and, as such, it receives attention only as damage reducing exercise. Design for safety and risk-based design have made tremendous inroads in delivering the message that due attention to safety over the life-cycle of the vessel provides the right platform for a cost-effective economic activity whilst serving the higher societal goals. This paper targets to reinforce this belief by providing a methodological treatment of damage ship dynamics whilst addressing the ensuing risk of flooding and offering solutions that have found their way in the maritime industry.