Safety of LNG-Fuelled Cruise Ships in Comparative Risk Assessment

Liquefied natural gas (LNG) as a marine fuel is already widespread in the ship-7 ping industry, but its application in the cruise sector, particularly in large cruise ships, is 8 still relatively new. By the end of 2024, twenty-four LNG-powered cruise ships will be in 9 operation, each capable of carrying thousands of passengers. The high passenger capacity 10 and frequent port calls require a rigorous safety assessment as the risks are higher than 11 those of conventional cargo ships. In this study, the safety of LNG-powered cruise ships 12 is assessed using the Formal Safety Assessment (FSA) method prescribed by the Interna-13 tional Maritime Organization (IMO). The assessment is divided into hazard identification 14 (HAZID), risk analysis, risk control options, cost-benefit assessment, and recommenda-15 tions for decision-making. Considering the limited operational data available for LNG-16 powered cruise ships, the study constructs event trees based on LNG tanker incidents, 17 modified to account for passenger-related risks and cruise ship-specific operating condi-18 tions. In addition, a statistical overview of marine casualties involving cruise ships and 19 LNG carriers with a gross tonnage of 20,000 or more over the last 35 years is provided. To 20 ensure compliance, this study examines the class and regulatory frameworks, focusing on 21 risk assessments required for the design of LNG-powered ships, bunker operations, and 22 emergency preparedness. These risk assessments, which are conducted at multiple levels 23 — including component-specific, ship-wide, and procedural risk assessments — are es-24 sential for safety validation and regulatory approval. This study provides a comprehen-25 sive framework for assessing LNG safety in the cruise industry by synthesising existing 26 safety data, regulatory standards, and probabilistic risk models. The results contribute to 27 the ongoing discourse on alternative marine fuels and support decision-making by ship 28 operators, regulators, and industry stakeholders.