Enhancing Collision Prevention Between Ships in a Close-Quarters Situation Using Simulated Avoiding Strategies

“Close-quarters situation” is the term that appears in the International Regulations for Preventing Collisions at Sea, but it lacks a precise definition. For this reason, the authors explore various interpretations and definitions provided by different scholars and court rulings, relying on legal precedents and judicial decisions. Ultimately, they propose their own definition of the term. Each navigator aims to establish the minimum safe distance from another vessel and the time until the closest point of approach within which a collision can still be avoided through appropriate action. Based on the proposed definition of a close-quarters situation, simulations were conducted using a navigational simulator to establish the minimum safe distances and the time frame in which a vessel can still maneuver to prevent a collision. A total of 168 simulations were performed, utilizing three different sizes of fine-form vessels and three sizes of full-form vessels. Due to the extensive data set, this paper presents results for only two vessels. To facilitate a better comparison of the maneuvering characteristics of different hull forms, one fine-form vessel and one full-form vessel of approximately the same dimensions were selected for analysis.