Improved outflow model for oil tankers following collision events and investigation of relevant statistical properties by Monte Carlo simulation

The paper focuses on the development of an improved outflow model for oil tankers following collision events and the investigation of its statistical properties by Monte Carlo simulation. After a review of the most recent advances, a new oil outflow model is developed for double hull oil tankers, based on a time-domain iterative procedure, until hydrostatic equilibrium is reached at outer and inner side openings. The model allows removing the assumptions related to the negligible dimension of the damaged area, the full loading condition of cargo tank and the detachment of the oil spillage event in a set of subsequent phases. The IMO statistics are employed for random generation of collision damage events, under different assumptions concerning the damage dimensions, assumed both uncorrelated and correlated, in the latter case by the employment of Gaussian copula functions. Two oil tankers are considered in a benchmark study, devoted to investigating the oil outflow statistical properties following collision events and comparing them with the relevant values obtained by the IMO model. The incidence of double hull width is investigated and some suggestions for the possible updating of current IMO guidelines are also provided to improve the safety of oil tankers following collision events.