Risk Assessment of Fishing Vessels Using Fuzzy Set Approach

The data available from fishing vessels are scarce and often accompanied with a high degree of uncertainty. For this reason the use of conventional probabilistic risk assessment may not be well-suited. This paper proposes a method using fuzzy set theory (FST) to model the occurrence likelihood and consequences of failure for the identified hazards on a fishing vessel. The method uses fault tree analysis to calculate the fuzzy probability of the system failure. The consequences of failure for each basic event within the fault tree are considered for 4 different categories. The risk of the basic events is determined by combining the likelihood of occurrence and consequences of failure in linguistic terms and is further defuzzified to produce a risk ranking. The application of this method is demonstrated using a hydraulic winch operating system of a fishing vessel.