Onboard Decision Support Systems (DSS) for energy-efficient maritime route planning are key for global carbon reduction
and sustainable transportation goals. Research indicates seafarers’ fuel reduction behaviors are hindered by goal conflicts
and workload, affecting motivation and efficient use of automated systems. We studied seafarers’ (N = 22) interactions with
a DSS in a high-fidelity bridge simulator, assessing Usability, User Experience, Workload, Basic Psychological Need (BPN)
fulfillment, and conducted interviews. Positive system evaluations, particularly hedonic User Experience, contrasted with
perceived reduced autonomy using the DSS. Seafarers often requested autonomy-enhancing features (e.g., route editing). Our
findings underline the importance of BPNs, especially autonomy, in human-centered technology for maritime transportation,
contributing to environmental and efficiency goals.