SAFEDOR: A practical approach to model the action of an officer of the watch in collision scenarios

The integration of risk and reliability analysis methods into the design process leads to a new evolving concept called "risk-based design". The application of this concept to the ship industry is the main subject of the EU project SAFEDOR (Design, Operation and Regulation for Safety). Within this framework the task in which the current work places itself aims at estimating the so-called causation factor for collision events, with due account to the integrated bridge system. The causation factor describes the probability that the operator react in time when two vessels are on collision course. The present paper illustrates the modeling of the causation factor. The focus is on emergency response actions that is to say the ship under power is assumed to be already on a collision course with another vessel. The model has to be implemented in a Bayesian Network that should take into account the overall causation factors affecting the probability of the operator not reacting in time. In this early stage the probabilistic modeling in the Bayesian Network mostly rely on the use of the Expert Judgment. However, the assessment is tailored in such a way that it might be possible to integrate observational data coming from training sessions.