“桑吉”号油轮沉没原因推测与分析

Deduction and analysis of the cause of the sinking of the Sanchi tanker

针对"桑吉"号油轮与"长峰水晶"号散货船碰撞着火后沉没的海难事故,本文基于事件梳理和船舶事故极限状态设计原理,开展了油轮沉没主要原因的推测和计算分析。对该事件进行了回顾并梳理相关重要信息,推测油轮沉没的一种可能原因:在碰撞受损的基础上,由于持续高温燃烧和交变波浪外载荷作用,导致高温区域船体钢材机械性能退化和结构塑性应变累积,造成碰撞受损区域局部构件撕裂和舱段剩余强度不足,进一步引发相邻舱室的总强度不足和大规模破舱浸水,一系列连锁反应,最后导致"桑吉"轮因储备浮力不足而整体沉没。在此基础上,根据事故现场的海况信息和沉没原因的推测,采用相近吨位油轮开展了破舱浸水后储备浮力和碰撞起火后船体剩余强度分析,计算结果在一定程度上验证了沉没原因推测的合理性。

The stricken tanker Sanchi sank after one week of burning following a collision with the bulk freighter CF Crystal in the East China Sea. In this paper,based on an analysis of the reported development of the accident and the theory of the limit state of damaged ships,we analyze the cause of the sinking and perform a case-study numerical analysis. We review the event and extract detailed information from which we deduced the following cause for the sinking： in addition to the structural damage sustained in the collision,the continuous burning and alternating external wave load led to the degradation of the ship steel＇s mechanical properties and the accumulation of plastic strain,which caused cracking of local structural members in the damaged area and insufficient residual strength of the cross-section. This resulted in insufficient overall strength of the adjacent cabins and large-scale flooding. This chain reaction eventually led to the sinking of the Sanchi due to its insufficient buoyancy reserve. Based on our deduced cause of the sinking and the possible sea states at the accident site,we conducted analyses of the reserve buoyancy of a damaged hull and the residual strength of a burned ship for an oil tanker of similar tonnage. The obtained results reveal that the deduced cause of the sinking is reasonable to some extent.