Trust your MUM: Trust as a Pillar of User Acceptance for the Autonomous Modifiable Underwater Mothership (MUM)

Abstract

Within the Large Modifiable Underwater Mothership (MUM) project, a consortium of research institutions and industry partners is developing a modular, fuel cell-powered underwater vehicle capable of extended autonomous operations. Its unique design aims to support missions in remote, high-risk, or high-latency environments - such as unexplored regions beneath Arctic ice - where human presence is limited or unfeasible. However, enabling such autonomy requires a transfer of control from human operators to the system itself, making the operator's trust in the system a critical prerequisite for acceptance. This paper explores the complex relationship between trust and control in autonomous maritime systems through a mixed-method approach combining qualitative exploration and conceptual analysis. Findings highlight three interrelated dimensions: first, trustworthiness emerged as a key operator expectation, grounded in both technical performance and the credibility of human actors behind the system. Second, the rationale for autonomy versus human control revealed persistent ambivalence - participants acknowledged the benefits of autonomy but also expressed a strong desire to maintain human oversight, particularly in ethically or operationally uncertain scenarios. Third, the interplay between human-machine coagency and perceived control proved central to trust formation. Participants were more willing to delegate control when they retained a sense of personal agency, even without actual intervention capacity.