Operational Strategies for ROVs in Underwater Search and Rescue During Large-Scale Marine Disasters

Underwater search and rescue operations during marine disasters are generally constrained by harsh ocean environments, which limit the operational time and safety of manned diving. This study aimed to evaluate the strategic integration of remotely operated vehicles (ROVs) with manned diving to enhance the operational efficiency and diver safety. For this purpose, the classification systems of ROVs defined by IMCA and ISO were reviewed. Furthermore, a compact-class ROV with field applicability was selected as the study subject. Using tidal current predictions for the Sewol ferry disaster site, the operational durations of self-contained underwater breathing apparatus (SCUBA) and surface-supplied diving systems (SSDS) were quantified based on threshold current velocities. The potential operational time of the ROV under identical conditions was then analyzed. This was followed by an evaluation of the feasibility of its integration with manned diving systems. The results indicated that ROVs could operate significantly longer than manned diving systems in both mild and harsh tidal conditions. A four-phase deployment strategy (standby, pre-dive ROV tasks, manned diving, and post-dive ROV tasks) was proposed. The study highlights the importance of strategic ROV deployment as a complementary tool rather than a replacement. The strategy would support rescue commanders in making informed decisions, ensuring safety, and improving the underwater operational effectiveness.