Fuzzy fault tree analysis for loss of ship steering ability

Abstract

Marine accidents have devastating effects on human life, the environment, and the economy. This study investigated the root causes of accidents resulting from the loss of a ship steering ability using Fuzzy Fault Tree Analysis (FFTA). Failure of the steering gear's hydraulic power, failure of the rudder, and failure of the steering gear's control are the three most common causes of loss of ship steering ability. Due to the difficulty in obtaining exact probabilities, the linguistic judgments of experts were used to determine the probabilities of each event's occurrence. The results showed that “steering gear hydraulic power failure” has the highest occurrence probability, followed by “rudder failure” and “steering gear control failure” in descending order. The occurrence probability of the top event, loss of steering ability, was calculated as 4.86E-02. An examination of the minimum cut set (MCS) identified “oil leaking through sealings to surrounding” as the most dangerous event. The MCS with the lowest occurrence probability was a combination of a main power supply failure and an emergency power supply failure. The findings of this study have made substantial theoretical and applied contributions to maritime safety, environmental protection, and the global economy.