ABSTRACT
Aim of this paper is to present a semi-probabilistic, semi-deterministic methodology to evaluate the risk of dangerous spills, and related public and environmental hazard, associated to the navigation in a narrow channel-port.
Our model uses the Monte Carlo method with variance reduction techniques, such as forced collisions and linear extractions to calculate the probability, location and consequences of several kinds of accidents.
A crude Monte Carlo technique is used to choose the tipology of the ship, the route followed, the substances carried and the gross tonnage.
We apply the conditional probability principles to assess the frequencies and the impact of the accidents occurring to moored ships (whose location is known).
In this way, using the Monte Carlo technique, we can simulate the spatial distribution of incidents along the channel, starting from global information about it.
Moreover, variance reduction techniques yield an acceptable error value with a number of histories much lower than using the Crude Monte Carlo. The simulation of the system in study can be performed automatically by a package of two programs: the first (input module) accepts the topological and traffic information about the port; the second (simulation module) simulates the port and the traffic using the inputs created by the first. The simulation program can handle sensitivity analysis.
Finally, we present the results of the application of our model to an idealized but realistic situation of channel-port.
