Safety Analysis and Decision Making Methodology in Ship Towing System Design

Abstract

In this paper, a quantitive safety analysis method was proposed to deal with decision making problems of ship towing system design. The method consisted of three steps: (i) mission phases and hazards identification; (ii) subjective assessment of mission phases and hazardous events; (iii) safety assessment and decision making. Subjective probabilities, which were derived with fuzzy fault tree analysis, were used for overcoming the difficulty of obtaining relevant historical data in salvage engineering, and entropy method was utilized to revise the hazardous events’ subjective weights. Three typical mission phases and their hazardous events were researched throughly in ship towing system, and then a safety analysis and decision making model was introduced subsequently. A case was studied to demonstrate the application of the model, and the results show that human factors (e.g. choices of tugs and towing rigs, towing watching, and towing operating) are vital for system safety, and should be paid more attention to in decision making of ship towing system design.