Considerations to the Probabilities of Collision of Ships by a Model of Collision Avoiding System

Author had proposed in his previous paper a model for estimating the probabilities of collision of ships at waterways applying the queuing theory to the relation between collision avoiding maneuvers and marine traffic. The improved model of collision avoiding system in the present paper was represented by two parameters named the intensity and the allowance of collision avoiding maneuvers, of which the practical meanings of ship handling were discussed. The model was applied to the ships navigating through the ten narrow channels in Japan in order to study the feasibility of the model. The probabilities of collision of ships at each channel by the model were compared with their statistical rates of collision there in last five years and their agreements were found to be good except the low values of the probabilities of collision. Based on the model, the situations of collision and the factors which had influences on collision were quantitatively investigated. It would be capable by the model for us to evaluate the effects of traffic controls and endeavors of navigators to prevent collision on the probabilities of collision.