To assess the safety of people and cargo onboard, severe environmental conditions are to be taken into account. In such conditions it could be necessary to use tools allowing the simulation of the nonlinear behaviour of a vessel free running and manoeuvring in waves. The need for applying such advanced tools in certain situations is one of the outcomes of the IMO discussion on the development of Second Generation Intact Stability Criteria, and, in particular, regarding tools for “Direct Stability Assessment” and for the development of ship-specific operational guidance. Within this context, a nonlinear time domain simulation tool is applied in this paper for the case of a container vessel. Simulations have been carried out considering the vessel free running in irregular waves. A set of conditions have been specified for identifying human-related, systems&machinery-related and cargo-related failures from time domain simulations. Some results are reported and discussed.
