Structural Safety Study And Integral Wreck Removal Operation

With increase of awareness to protect marine organism and environment,it also raises that the requirement of oil spill control during wreck removal project.Normally the millions of tons DWT vessel needs about thousands of tons fuel oil for their voyage.In addition,the ancient wreck salvage also require the wreck and cargo to be integral salvage.Therefore the integral wreck removals is becoming a major trend.For such reason,the stability,longitudinal strength and local strength analysis of integral wreck removals during refloat is the key of removal plan.In this paper,the study is based on the Trans Summer--57000 T bulk carrier wreck removal project,which is the biggest integral wreck removal project of bulk carrier in the world.The study aims at assurance of safety of integral wreck removal,analyzing the longitudinal and local strength of wreck.During the wreck refloating,divided the refloating process into 8 steps,then use GHS to simulate and analyze the floating status,stability and longitudinal strength of wreck.Therefore,the most dangerous load case is under control and can be adjusted.Besides,a finite element model of the wreck is created to analyze the local strength for the most dangerous load case,which is de-ballasting the No.4 cargo hold to refloat the wreck.The impact operation,safety factors and the salvage process,such as oil removal,discharging cargo,righting the wreck and refloating wreck are narrated in this paper.Then applied above mention factors and operations to optimize the salvage scheme,identify hazard and prepare mitigation measures.With the trend of more large-sized vessels,the wreck size of integral removal is becoming larger and the structure of wreck is also becoming more complicated.Therefore,the strength analysis of wreck is very important.The information,simulation and precision of the salvage operation process is key technical support and able to optimize and control the salvage process.