## 1 Introduction  
As one of the world's largest seafarer-producing nations, Indonesia plays a critical role in supplying qualified maritime personnel to the global shipping industry. With a maritime workforce spanning thousands of vessels worldwide, the country has made continued efforts to enhance the competence, adaptability, and safety awareness of its seafarers in line with international standards [1]. This commitment is particularly vital given the increasingly complex navigational environments and stricter global safety regulations. Among the most effective tools for maintaining and improving seafarer competence is simulation-based training, which enables navigators to experience high-risk scenarios (for example, a ship encounters in restricted waters) without real-world consequences. Simulator-based learning offers a controlled, repeatable, and measurable platform for developing technical skills, decision-making, and stress management under pressure. This approach is especially valuable in countries such as Indonesia, where preparing seafarers for international deployment requires both technological capability and contextual relevance [2]. Accordingly, this study leverages the experience of Indonesian navigators to investigate the physiological and psychological impacts of encounter scenarios derived from real automatic identification system (AIS) data, thereby contributing to the global research and advancing locally grounded maritime education and training. Despite the growing body of international research on simulator-based training, few studies have specifically addressed how ship navigators operating in dense and complex traffic environments experience stress during close-quarter encounters. The existing studies have largely focused on generic simulation tasks or non-specific traffic patterns, leaving a gap in understanding how culturally and operationally distinct navigators manage stress in realistic, data-driven scenarios. This study builds upon our previous research on maritime traffic risk assessment, where we integrated the functional resonance analysis method (FRAM), an AIS trajectory analysis, and risk mapping to identify high-risk encounter zones and sociotechnical variability in vessel traffic services (VTS) operations [3]. While the prior study focused on mapping systemic risks and predicting accident-prone areas from an operational perspective, the present study extends this inquiry by examining how such risk-laden navigational situations impact individual navigator stress responses. By situating the stress analysis within empirically identified high-risk encounter zones, this research bridges systemic risk assessments and human-centered performance analyses. Understanding the effects of ship encounters on navigator stress levels is crucial for improving maritime safety. These situations, characterized by high cognitive demands, require navigators to make rapid decisions under pressure. According to cognitive load theory, the human brain has a finite capacity to process information, and when overloaded, this capacity can impair performance, leading to errors and accidents [4]. Ship encounters can cause a rapidly increased cognitive load, which in high-stress environments may delay response times and elevate the risk of human error [4]. By examining how Indonesian seaferers respond to close-quarter ship encounters within a controlled simulator environment, this study aimed to uncover the dynamic relationships between perceived stress, cognitive workload, and physiological stress responses across varying encounter geometries. Each simulated scenario reflects realistic navigational conditions commonly experienced in dense traffic areas, thereby preserving the ecological validity. The encounter designs were derived from our prior marine traffic risk assessment study [3], ensuring alignment with empirically identified high-risk patterns.