Comparative analysis of IMO autonomous ship degrees in different dimensions and a model proposal for selection of ideal autonomous ship degree

This study aims to systematically evaluate the levels of Maritime Autonomous Surface Ships (MASS 1, 2, 3, and 4), as defined by the International Maritime Organization (IMO), through Multi-Criteria Decision Making (MCDM) methods to determine the most appropriate level of autonomy. The assessment is structured around four main criteria, cost, safety and security, technical adequacy, and social impact, and is further detailed through relevant sub-criteria. The weights of the criteria were determined using the Fuzzy Analytic Hierarchy Process (FAHP), which incorporates expert judgment under uncertainty. The alternatives were ranked using the Grey Relational Analysis (GRA) and the Weighted Aggregated Sum Product Assessment (WASPAS) methods. The findings indicate that, across all applied methods, MASS 4, representing full autonomy, emerges as the most appropriate option at present, when all evaluation criteria are considered. Among the criteria, safety and security were found to be the most critical factor (33.7%), followed by cost (31.6%), technical aspects (23.6%), and social considerations (11.1%). At the sub-criterion level, cybersecurity risks, investment and maintenance costs, system maintainability, and training requirements played significant roles in shaping the results. In conclusion, the study highlights that the adoption of autonomous maritime technologies should not be guided solely by technological feasibility but must also consider safety, cost-effectiveness, and societal acceptance. The findings provide a scientifically grounded basis for policymakers and stakeholders in developing strategic roadmaps for future maritime autonomy.