Application of fuzzy logic to fault tree and event tree analysis of the risk for cargo liquefaction on board ship

Risk analysis is of paramount importance in maritime transportation due to the nature of work. The IMO (International Maritime Organization) adopted FSA (Formal Safety Assessment) as guidance to address risk analysis on-board ship. However, it does not suggest a specific approach on how to assess the risks. Therefore, safety researchers are seeking robust risk analysis approaches in maritime transportation. This paper performs comprehensive risk analysis by using bow-tie method within a fuzzy logic environment. While the bow-tie method is analysing potential causes and consequences of failures, the fuzzy logic deals with vagueness and imprecision of expert judgements. The case of cargo liquefaction on-board ship is selected as a case study since the consequences of cargo liquefaction are extremely dangerous for crew, ship and environment. Besides its theoretical insight, the paper supports maritime professionals to enhance safety awareness about the cargo liquefaction phenomenon.