The traditional way of assessing the operational risk of passenger ships is based on the concept of susceptibility and vulnerability to an accident. Such an approach is mainly used to study the possible risk in given operational scenarios, adopting simplified quasi-static methods to assess the vulnerability of the vessel and using empirical definitions for the damage breach modelling. These methods are not employing first-principles methods for the risk evaluation and are not suitable for the development of onboard real-time risk assessment. To this end, developments in the EU-founded project FLARE led to a multi-level risk assessment framework based on first principle methods, that can be applied as a basis for an onboard risk assessment in real-time. The framework for real-time assessment is based on the development of databases for damage locations and dimensions and survivability. Here, the development of a suitable database of damages is discussed, concerning the employment of direct crash simulations with the software SHARP, aiming at developing a database of collisions suitable for a general operational scenario. The resulting database can be used as a data source for the development of a surrogate model for fast application in real time. This paper addresses the application of the process to a reference cruise vessel.

Real-time assessment of flooding risk associated with the collision between two ships, requires a fast estimation of damage dimensions and associated survivability. The state-of-the-art frameworks for risk assessment on passenger ships do not consider a direct evaluation of damages through crash simulations but refer to probabilistic considerations, modelling damage characteristics according to statutory marginal distributions of damage breaches too old to be any longer relevant. In any case, such an approach is not possible for the real-time risk assessment process developed in project FLARE, aimed at promoting the employment of first-principles tools for risk evaluation. In this spirit, the present work investigates the possibility of developing a database-oriented damage breach model, which employs direct crash analyses with the super-element code SHARP. However, the sole usage of crash simulations is not suitable for real-time applications. Therefore, starting from the collision simulation database, surrogate models have to be derived for real-time application. In this specific case, three different strategies have been used for the models creation namely: multiple linear regressions, neural networks and decision trees. Here, the strategy to build the database and application on a reference passenger ship is described, highlighting the differences in accuracy and calculation time between the proposed surrogate models.

The paper complements an earlier publication by the authors addressing the probability of survival in the IMO framework for damage stability assessment, the s-factor. The focus here is on the probability of occurrence of a certain damage scenario (breach), conditional on its dimensions and location (centre and port or starboard side), the p-factor. Pertinent assumptions and limitations are explained, following its evolution for specific application to passenger ships. Attempts to provide analytical descriptions of the damage breach distributions as tetrahedra shapes positioned along the ship length whilst accounting for changes in ship geometry, structural arrangements, and subdivision for consumption by the wider profession has led to misconceptions and misunderstandings of what exactly the p-factor is in the context of probabilistic damage stability calculations. This is evidenced by the fact that the same original damage breach distributions, derived in Project HARDER, based on largely cargo ships with the age spread over the last three decades of the previous century, are still being used today for all ship types, including modern passenger ships. Filling this gap, a new database for passenger ships developed in the EC-funded Project FLARE, is briefly presented, leading to new damage breach distributions specifically for passenger ships. It is believed that this paper will throw considerable light in enhancing understanding on the p-factor, which has been cluttered with unnecessary complexity from the outset.