A Sustainable Framework for Planning and Management of Diving Operations for Underwater Search and Rescue in Strong Tidal Current Environments: Lessons from the Sewol Ferry Disaster

Maritime disasters pose substantial social and economic challenges and often require complex, resource-intensive search and rescue operations to minimize loss of life and damage to infrastructure. This study proposes a sustainable and quantitative framework for planning and managing underwater search and rescue operations in strong tidal current environments, with reference to the Sewol ferry disaster. Hydrodynamic current predictions over a 31-day period were analyzed to determine tidal-induced diving cycles and to estimate the depth-specific diveable time (DAT) under safe operating limits of 1 knot for a self-contained underwater breathing apparatus (SCUBA) and 1.5 knots for surface-supplied diving systems (SSDSs). Two representative dive profiles were developed: a no-decompression SCUBA plan for 26 m hull diving and a staged-decompression SSDS plan for 48 m seabed diving, considering oxygen toxicity and nitrogen narcosis limits. Workable time (WAT) analysis indicated SCUBA as optimal for hull tasks (WAT/DAT = 0.83), whereas the SSDS provided extended efficiency for deep-water operations. A redeployment model based on surface interval constraints reduced diver staffing requirements by approximately 28%. The proposed framework enhances the sustainability and resilience of marine disaster response by optimizing diver safety, operational efficiency, and resource management, contributing to sustainable marine safety systems and long-term emergency preparedness.