Study On Anchoring Safety Analysis Based On Fuzzy-FTA Method

Ship's quarantine.waiting for tide.anchorage transship or seeking for shelter shall all be conducted in the anchorage,the safety of ship during mooring period has become one of the essential parts in ship safety operation.The trend of ship design and construction has made ship scale turned to be larger,and the increase of tonnage of ships.With the increase of new ships,performance of old ships could not meet the requirements of modern shipping industry,thus they would gradually be abandoned and discarded.Furthermore,shipping market has not been recovered.some off-stream ships have increased the burden of anchorage.The anchorage therefore has become more crowded,this leads to the increase of anchorage risk.It is very important to research on mooring safety.Numerous experts and scholars had done a lot of research on mooring safety issues,put forward many opinions and research ideas.The ultimate purpose is to enhance anchoring safety.Combined with the related literature,on the basis of previous research.this paper will introduce the method of Fault Tree Analysis into anchoring safety research.Through analysis of the factors that will influence the safety of anchoring safety,this paper consider the unsafe status 'of anchoring as top event,meanwhile the influence factors as intermediate event or bottom event.And then construct an anchoring fault tree.This paper will use the method of Fussel-Vesely to calculate minimum cut set in the process of qualitative analysis.The author conducts questionnaire survey to collect data about the rankings of fault probability and the accuracy of probability determination.Then base on fuzzy mathematics method to run both qualitative and quantitative analysis on probability of bottom event and its effect on top event,and obtain the occurrence probability of top event.Finally rank the influence importance degree of the bottom events,depict the event set which has more influence on anchoring safety.And make some pertinent suggestion on mooring safetry,provide a new thought for mooring safety analysis.Meanwhile,to verify the feasibility of Fuzzy-FTA in the field of anchoring safety analysis,this paper adds fault tree analysis to fuzzy comprehensive evaluation,give weights of bottom events using weightiness method.Through fuzzy decision,calculate the event which has the greatest probability leading to mooring accident.The calculation process of this research could provide a basis for seaman and officers to guarantee anchoring safety.The conclusions and suggestions could also provide references for the protection of anchoring safety.