## 5 Discussion
Specifically, the participants holding ANT II licenses exhibited higher frustration levels than those with ANT I, implying that their licensing level may influence their cognitive appraisal of their workload, especially under conditions of task ambiguity or time pressure. No significant differences were observed across the last duty rank or last ship type in any of the subjective workload or physiological stress indicators, indicating that an individual's prior operational context alone may not account for variability in stress responses during simulation-based tasks. The MW, which we initially thought would be crucial in the experiment, did not turn out to not have any effect at all on subjective stress, which may have been due to the short time of the experiment. Similarly, the experience of the subject also did not affect their stress, since all of the participants were aware that the closed-environment experiment was not real. The only factor that effected stress across all segments was age, whereby the younger participants had a higher mean RR interval (which translates to higher stress) than the older participants. This suggests that as an individual's age increases, there is a notable impact on their HR and HRV. This aligns with the idea that older individuals typically exhibit lower heart rates and less variability, which may explain the significant differences in mean RR intervals across age groups. However, the SDNN and RMSSD results did not show significant differences, possibly due to other factors such as individual health conditions or fitness levels, which can affect these measures. Although most of the research on marine traffic engineering is focused on artificial intelligence (AI), the results of this research could be of benefit to those developing collision avoidance assistance systems for use by navigators on ships. The simulator used in this study closely reflects real-life navigational conditions but its full potential should be further explored in future research. Several studies that also utilized simulator approaches with the MW and HRV being used in different navigation conditions indicated that varying levels of navigation tasks led to significantly different MW and HRV values. Both the MW and HRV increased as the task difficulty heightened [52]. A model was also developed to recognized the navigator's workload using a support vector machine. This approach showed that the changes in various eye movement features varied across different workload levels, and it proved to be a high-accuracy model; the same tasks were also conducted in a simulator [56]. Biosignals were also utilized to assess maritime students' stress levels, suggesting that training scenarios can be categorized based on stress levels, which were associated with factors such as reduced visibility, equipment malfunctions, and extreme weather conditions. Furthermore, the study showed that elevated stress levels can impair performance in maritime navigation and affect the reliability of sailing routes. These findings offer actionable insights to improve the quality and effectiveness of maritime training programs, ultimately enhancing the navigational safety at sea [57]. While this study did not employ AI directly, its findings on the encounter geometry and stress responses can inform future AI-based navigator support systems, particularly in adaptive risk-aware training protocols and collision avoidance tools. Although the spatial distance to nearby ships in close-quarter encounters was not directly analyzed, segment 2 emerged as the most stress-inducing scenario based on statistical findings for both the PSS scores and LF/HF ratio. This segment typically involved the individual's own ship facing incoming vessels from both the 135\({}^{\circ}\) port and starboard bearings, creating a perceptual burden due to increased peripheral awareness demands. Observationally, many of the 24 participants frequently noted simultaneous ship movements on both sides while also maintaining attention toward the fairway ahead.