The research for effective methods to avoid ship collisions has become important with the increasing size, speed and number of ships participating in sea transport. Ever since the application of the Automatic Radar Plotting Aids (ARPA) anti-collisions systems made its debut the safety of maritime navigation has increased [12], [13], 18].
According to Lloyd's statistics, in about 87% of marine accidents, the cause of ship collisions is the navigator's subjectivity in maneuvering decisions, often under conditions of ambiguity and conflict. Therefore, among the many possibilities of describing this process, the models of fuzzy control and game control become the most useful.
A new tendency within the contemporary domain of ship control involves an automation process of selecting an optimal manoeuvre or optimal safety trajectory, based on the information obtained from the anti-collision system [25], [26]. This paper discusses the solution to the task of determining the ship's optimal course at every stage of ship trajectory planning, based on the kinematic model with the assumption that the motion of targets is uniform and occurs as a straight line [14], [24], [28]. Due to the fuzziness of the process and an individual approach of a particular officer-navigator, the decision-making process is also, to some extent, an ambiguous evaluation of the safe approach distance and safe time to manoeuvre so as to avoid collision [23]. Moreover, it is assumed that an optimal safe trajectory in a collision situation is a multistage decision-making process in a fuzzy environment (Fig. 2) [4]-[6].