A Study on the Analysis of Navigators' Understanding of COLREGs Navigation Rule Interpretation and Ship Encounter Situations

Abstract

The Convention on the International Regulations for Preventing Collisions at Sea (COLREGs) consists of rules designed to prevent collision incidents in maritime environments. These rules are based on the qualitative rules of seamen and ordinary practices. With the influence of the Fourth Industrial Revolution, research on autonomous navigation in ships has emerged, known as the advent of Maritime Autonomous Surface Ships (MASS) by the International Maritime Organization (IMO). Since MASS operates autonomously, research on technologies for automatic collision avoidance has been presented. Various collision avoidance algorithms have been developed based on the COLREGs, which serve as rules for preventing collisions. However, the qualitative nature of the COLREGs has led to issues in the interpretation of navigation practices. Previous studies have addressed this need by investigating how actual navigators interpret navigation. The perception of collision avoidance situations was surveyed among real navigators, focusing on head-on, crossing, and overtaking scenarios. Three types of ship encounters were distinguished based on radar screens used on actual ships: head-on situations, crossing situations, and overtaking situations. The speed vectors remained constant, while the bearing angle was adjusted by 2 to 5 degrees for the survey. In this study, surveys were conducted with approximately 100 actual navigators, and the collected data were analyzed through statistical analysis and modeling to apply the results to maritime collision situations. Curve fitting using distribution functions based on navigation interpretation zones was utilized to apply navigators' understanding of navigation situation. This study provides an understanding of navigators' interpretation of navigation in relation to the COLREGs, and it also allows for a comparison with collision avoidance algorithms developed for autonomous ships through the use of models. In addition, the results of this study provide clues to solve the introductory different navigation interpretations even if the rules are not changed through the understanding of COLREGs.