Rationale for selecting a risk assessment method for unmanned tug operations in a port area

Abstract

The article examines risk assessment methods for the operation of an unmanned port tug in port waters. The relevance of the study is determined by the increasing tonnage and dimensions of serviced vessels and the active introduction of autonomous shipping technologies, including MASS at the second level of autonomy according to the IMO classification. At this level, the system independently performs basic navigation and manoeuvring tasks, while a shore-based remote operator monitors its operation and intervenes only in abnormal situations. The transition to unmanned operation substantially changes the structure of operational risks: risks to people on board are reduced, whereas the significance of autonomous system failures, loss of communication, cyber threats, and remote-operator errors increases under conditions of intensive port traffic. Based on an analysis of Russian and international scientific literature, modern risk assessment methods, including HAZOP/CHAZOP, SWIFT, HRA, PHA, and scenario analysis, are reviewed. Their advantages and limitations for highly automated and remotely controlled technical systems are identified. A combined approach integrating Preliminary Hazard Analysis, the Structured What-If Technique, Human Reliability Assessment, and expert assessment is substantiated. A comprehensive risk assessment map comprising 12 key groups of hazards is developed. Critical risks associated with severe weather conditions and cyber threats are identified, their probability and consequence severity are assessed on a five-point scale, and organizational and technical risk-control measures are proposed. The results provide a methodological basis for developing a risk inventory, a safety management system, operational documentation, and further regulatory provisions for the safe operation of unmanned port tugs.