A subjective modelling tool applied to formal ship safety assessment

Formal safety assessment of ships has attracted great attention over the last few years. In this paper, following a brief review of the current status of marine safety assessment, formal ship safely assessment is discussed in detail. A subjective safety-analysis-based decision-making framework is then proposed for formal ship safety assessment in situations where a high level of uncertainty is involved. In the framework, failure events at the lowest level are modelled using fuzzy sets and safety synthesis at the different levels of a hierarchy is carried out using evidential reasoning. Multiple safety analysts' judgements can also be synthesised using the framework. Subjective safety and cost assessments obtained can finally be combined to produce the preference degrees associated with the design/operation options for ranking purposes. An example is used to demonstrate the framework. (C) 2000 Elsevier Science Ltd. All rights reserved.