Elements of Risk Analysis for LNG Tanker Maneuvering with Tug Assistance in a Harbor

摘要

An analysis of a collision scenario between a liquefied natural gas (LNG) tanker and a harbour tug during mooring operations is presented in this paper. Usually two phases of this operation may be recognized: first a meeting of an assisted vessel with tugs on harbour roads and second docking operations. This paper addresses the first phase, in which the tugs are approaching the LNG tanker at a certain speed, very often at a full sea speed, and therefore may pose a certain hazard in case of a collision with the LNG tanker. Firstly the angle of impact and the speed of the tug which causes the hull rupture is calculated by means of series of dynamic simulation using the non-linear finite element method (FEM). Secondly, the conditional probability of tug-LNG tanker collision is calculated using a Bayesian Network (BN). As consequences of the collision, costs of tanker hull repair are considered. Finally the annual risk, expressed as a combination of probability of an accident and its consequences is calculated.