## 1 Introduction  
Understanding how navigators behave when they are involved in a ship collision is crucial for preventing collision accidents caused by human error, which remains a major cause of shipping incidents [1; 2; 3]. In relation to this, behavior models of navigators who operate in complex, high-risk domains are of great value because of high losses due to navigator failure [4; 5]. To ensure the safety of maritime transportation, scientific measures must be taken to respond to and prevent various types of maritime accidents, instead of having ambiguous anticipations of possible human errors [6; 7; 8]. Although international rules have been reinforced by International Maritime Organization (IMO) to avoid navigator error, the accident caused by human error continues to this day [3; 8]. Recently, the causes of accidents were induced by a model to assist with accident prevention, and the concept of accident causes found in the researchers' models was explained and discussed; however, none is yet generally accepted [9]. Human error is continually quoted as the source of an accident. However, the solution is thought to change its role in people or systems, and it is not really simple. Human error must link human behavior through the process [10]. Based on a recent assessment [11], navigator error was involved in 79% of accidents in the Republic of Korea over the last five years, and inappropriate behavior accounted for 49% of all maritime accidents [12]. Although most maritime accidents were suspected to be related to navigator error, evidence of navigator error has not yet been explored objectively [13]. Most existing assessments of a navigator's maneuvering behavior depend on indirect data collection methods, such as diaries, surveys, and questionnaires [14; 15; 16]. For example, [PERSON] et al. used a sample of 141 officers to investigate human errors of navigators via a survey of the importance of a navigator's behavior [17], and classify ship bridge work as a criterion for situational awareness for preventing navigator's error from occurring [18]. The use of such indirect approaches entails a subjective limitation for accurate observation of the maneuvering behavior of navigators during navigation. This limitation could be addressed using more objective data collection measures of a navigator's behavior. In relation to this, the authors of this study previously proposed an identification model of lookout activity using kinetic sensors [19]. However, there is still a lack of studies that investigate a navigator's behavior to measure maneuvering activity patterns in a ship collision environment.  
The purpose of this study is to establish a navigator's behavior model for ship maneuvering using a ship maneuvering simulator in a collision-encountering situation. The proposed maneuvering behavior model employed 100 senior cadets at a maritime university in the Republic of Korea. In the given navigation scenarios, the participants performed maneuvering behavior to avoid collisions between ships. The maneuvering histories collected by the simulator system were utilized to develop two behavior models--i.e., the success and failure models for collision avoidance--which were validated in terms of their discrimination powers. The main contributions of this study are the following: a scientific research framework for the investigation of a navigator's error from his/her behavior for ship collision avoidance, and objective evidence of how a navigator maneuvers a ship in water using control devices.