The Evaluation for Usability Methods of Unmanned Surface Vehicles: Are Current Usability Methods Viable for Unmanned Surface Vehicles? Insights from a Multiple Case Study Approach to Human-Robot Interaction

Unmanned Surface Vehicles (USVs) are increasingly utilised for diverse applications, ranging from environmental monitoring to security patrols. While USV technology is progressing, it remains clear that full autonomy is not achievable in all scenarios, and remote human intervention is still crucial, particularly in dynamic or complex environments. This continued reliance on human intervention highlights a range of Human-Robot Interaction (HRI) challenges that remain unresolved. Compared to the extensive body of HRI research in domains such as unmanned aerial vehicles and autonomous vehicles, HRI considerations specific to USVs remain significantly underexplored. Addressing this gap, our study investigates real-world usability challenges in USV operation through in-depth interviews with 9 engineers and users, supported by field observations. We focus especially on the difficulties beginner operators encounter and their coping strategies. Our findings reveal existing usability issues, mental models, and adaptation strategies of beginners that inform future user-centered design of USV systems, contributing new insights to the emerging field of maritime HRI. Based on these findings, we argue that current USV systems are poorly suited for beginner operation in dynamic inland and offshore environments, where operators must make timely decisions under uncertainty, manage complex spatial awareness, and adapt to changing environmental conditions. Furthermore, we identify key operational patterns in three representative use cases-harmful algal bloom detection, underwater concealed pipe inspection and post-construction hydrographic survey, and summarise key interaction constraints that should inform future maritime HRI design efforts.