Analytical Criteria for Collision Avoidance between Two Encountering Ships

Abstract

This study provides analytical criteria for collision avoidance between two encountering ships. The criteria determine the critical distance between the encountering ships at which evasive maneuvers must be initiated in order to avoid collision, given the relative motion and crossing angle between the two ships. Two different strategies for collision avoidance are addressed: speed change and heading change. A closed-form solution for the critical distance was obtained for each strategy, which provides comprehensive criteria in terms of the maneuvering capabilities and geometric configurations of the encountering ships. To demonstrate the validity of the proposed approach, its results are compared with the rules mandated by the International Regulations for Preventing Collisions at Sea (COLREGS) by the International Maritime Organization (IMO).