Navigator Responses to Safety Challenges in Autonomous Maritime Systems

Abstract

Maritime transport is a critical pillar for both economic development and societal security, essential to national resilience, energy supply chains, and geopolitical stability. The prospective integration of Maritime Autonomous Surface Ships (MASS) into existing fleets creates complex mixed-autonomy environments where safe interaction is crucial to prevent accidents with severe consequences for the environment, human lives, and societal wellbeing. Ensuring this safe interaction requires understanding how experienced navigators adapt to vessel behavior that deviates from established norms during close encounters. A critical knowledge gap exists in this area, posing significant risks to maritime safety and societal security. To address this, this study empirically investigated how the behavior of another vessel influences experienced navigators’ situational awareness, decision-making processes, and trust during safety-critical interactions.

An exploratory, mixed-methods approach was used with a sample of seven experienced navigators in a controlled, high-fidelity simulation environment. Data were collected using quantitative simulator metrics, eye-tracking, and NASA-TLX subjective workload assessments, alongside qualitative post-scenario interviews. Findings from simulator data showed evidence of adaptation in maneuvering behavior across scenarios. Eye-tracking metrics provided insights into visual attention patterns and physiological responses potentially related to cognitive load. NASA-TLX data indicated perceived workload, with a statistically significant negative correlation (rho = -0.54, p = .045) emerging between subjective effort and active maneuvering time. Findings from the qualitative interviews revealed that participants universally perceived the target vessel as non-compliant, leading to widespread low trust and challenged situational awareness, and provided insights into decision rationale and perspectives on interacting with hypothetical autonomous vessels. A combined analysis revealed significant correlations between specific eye-tracking dwell time metrics on main controls and instrument displays, and simulator behavior outcomes such as active maneuvering time and minimum distance. The unique case of one participant’s VHF uses also highlighted how communication outcomes may shape perceived predictability and influence workload distribution.

These results provide preliminary empirical evidence of navigator adaptation strategies when encountering unexpected vessel behavior in mixed-autonomy scenarios. The findings suggest that navigators adjust their decision-making processes and attention allocation when managing unpredictable interactions, potentially reflecting strategic adaptations to maintain safety margins under increased cognitive load. This study contributes understanding to a previously underdeveloped research domain critical for maritime safety. The results emphasize the need for designing predictable autonomous systems, implementing transparent communication protocols, and developing adaptive training strategies to support effective human oversight in mixed-autonomy environments, thereby minimizing interaction risk and enhancing both maritime safety and societal security.