About necessary and sufficient conditions to design safe ships: the appropriate ship design process

Focus of this paper is the evidence of strong interconnection between safety rules and design process especially for passenger ships. A change in the methodological approach for the safety framework might imply a strong renewal course also of the decision making process during the ship design, keeping in mind its unique peculiarities. After a general discussion about some open issues relevant to performance-based rules implementation, some considerations are given about specific points raised by the "Safe Return to Port" capability in relation with the ship design process. Finally, the high level of flexibility in principle guaranteed by performance-based assessment is discussed in relation with the difficulty to implement the design process as an optimization procedure, due to large amount of information involved and the complexity of problem in terms of objective functions and constraints.