Investigation into safety acceptance principles for autonomous ships

Maritime Autonomous Surface Ships (MASS) are expected to be introduced in the maritime industry with non-mandatory MASS code adoption due in 2026. However, there is still ambiguity regarding the acceptance principles that can be applicable to MASS and effective ways to use them as part of assurance process. In this paper three different types of safety acceptance principles, namely, (i) safety equivalence, (ii) As Low As Reasonably Practicable (ALARP), and (iii) equivalence to well-proven regulations, practice and functions, frequently referred in the international maritime regulatory framework are discussed and their advantages/limitations regarding application to MASS are identified. For that, findings in the field of risk science, public safety management and research connected to MASS are used. Based on this analysis and in line with IMO goal-based standards (GBS), suggestions are made on how to effectively demonstrate compliance under the different acceptance principles, to ensure public acceptance and alignment with existing regulatory framework. The application of alternative acceptance principles to MASS and some practical implications related to findings are also discussed. It is suggested that the policy decision-makers and regulatory bodies employ novel risk definitions, accept MASS considering to a greater extent the sociotechnical context and benefits, and use a mixture of metrics/approaches/principles/acceptance criteria.