Damage stability of passenger ships: smart methods to identify critical scenarios

The damaged stability assessment for a passenger ship is a process requiring the simulation of multiple damage scenarios. Nevertheless, due to the stochastic nature of both the damage stability framework and the irregular waves environment, a considerable number of cases must be analysed. However, the probability density functions used to estimate the possible damage dimensions and locations along the ship necessitate a large amount of scenarios that are not critical for the ship survivability, especially for large passenger ship. To restrict the amount of damage scenarios, it is common practice to apply empirical rules, such as critical damages are only above two compartments, considering that damage stability regulations currently in force, ensure survivability levels beyond this extend of damages. However, a rigorous approach is lacking. To this end, in the present work, it is proposed to use more scientific-based methods to filter critical damages. The first method is based on preliminary static calculations, the second on the energy absorbed by the ship during an impact, the third on a purely dynamic approach. The methods are here critically compared on two sample passenger ships, showing their respective advantages and disadvantages.