Sailing into the future with periodically unmanned bridges—a viable concept for mitigating seafarer shortages?

• Full-mission simulator used to empirically assess periodically unmanned bridges (B0). • Performance and overall workload were comparable between B0 and manned bridges. • B0 scenarios showed higher anticipatory situational awareness (SA3). • Navigators emphasized early alarms and clear decision-support to enable safe takeover. • Findings inform regulation and human-centred bridge system design for B0 operations. The maritime industry, particularly deep-sea operations, is facing increasing challenges related to crew shortages, fatigue, and compliance with rest and work-hour regulations. One proposed solution is the concept of a periodically unmanned bridge (B0), in which the bridge may remain unattended under certain operational conditions (e.g. open sea, clear weather, no technical defects). However, safe implementation of B0 requires addressing human, technological and regulatory challenges. This exploratory study presents one of the first empirical evaluations of B0 operations using a full-mission bridge simulator. Eight experienced navigators were interviewed after completing four realistic operational scenarios under two conditions: continuous bridge manning and B0. Post-scenario interviews were triangulated with data on navigator performance, workload ratings, and Situational Awareness (SA) measures. Participants highlighted opportunities and concerns related to B0, particularly regarding trust in automation, failure detection and the need for rapid re-engagement following alarms. They also noted that the concept may require new forms of training, information presentation, and decision-support systems. Results for performance, workload, and situational awareness were broadly similar between the two bridge types. Although tentative due to the limited sample size, the findings indicated a potential advantage for anticipatory situational awareness (projection) in the B0 condition. Overall, the findings suggest that B0 may be feasible within constrained operational envelopes, if alarm strategies, training, and human-automation interaction are carefully designed. The study contributes early empirical evidence to inform the development of decision-support requirements and regulatory adaptations in ongoing discussions regarding the potential implementation of periodically unmanned bridges.