Elements of risk analysis for collision of oil tankers

This paper presents a model for risk analysis for ship-ship collisions with emphasis on tankers. New adaptations of pre-existent physical models are presented. Probability of an accident is estimated with use of the MDTC model, which combines molecular collision theory and ship manoeuverability. Consequences of an accident are expressed in monetary terms, and costs of an oil spill due to an accident are considered. Neither loss of life nor structural damages were considered in the risk model. The costs are assessed with a model that is modified from procedures adopted by International Maritime Organization (IMO). Also an innovative model for deformation energy estimation in ship-ship collisions is presented. The presented study concerns selected area in The Gulf of Finland (GOF), which is one of the most densely trafficked sea areas in the world. The model input data is derived from Automatic Identification System (AIS).The Monte Carlo simulation method is applied to simulate number of collision scenarios depending on the encountering type. compensation figures approximate reasonably the real spill costs, this approach is well recognized, commonly adopted (Kontovas and Psarafitis 2008), robust and easy to use, and therefore it is utilized. The paper also introduces an innovative model for assessment of deformation energy released during ship-ship collision. The deformation energy in a collision scenario is calculated by applying method that Zhang proposed in his work (Pedersen and Zhang 1998), (Zhang 1999). The variables needed to apply Zhang’s method are based on data transmitted by ships via Automatic Identification System (AIS). The Monte Carlo simulation method is applied to simulate a number of collision scenarios depending on the encountering type. This model may be helpful to estimate the extent of the damages in a ship-ship collision and to calculate the size of the possible spill resulting thereafter. Presented study concerns waterways junction between Helsinki and Tallinn. A high number of passenger vessels operating on North-South route, between the two capitals is recorded every day. While on the crossing East-West route dense traffic of tankers and cargo vessels is observed. 2 COLLISION PROBABILITY MODELLING The collision probability prediction model presented in this paper is based on a molecular collision model enhanced by a model of ship dynamics,