Towards applicability evaluation of hazard analysis methods for autonomous ships

The introduction of autonomous ships is shaping the future of the global shipping industry. These ships have been successfully tested by stakeholders. The minimum safety requirement for autonomous ships is that their operation should be at least as safe as that of conventional manned ships. Hence, it is necessary to use effective analysis methods to conduct a systemic hazard analysis process since the earliest design phase of an autonomous ship. In this study, we investigate the applicability of 29 hazard analysis methods for autonomous ships. System safety requirements and evaluation criteria based on the characteristics of autonomous ships are established using a system engineering approach. To this end, under a review protocol, relevant and extensive studies in the past nearly 50 years are analysed in detail and clustering results of hazard analysis methods regarding the types of ship and the autonomy of levels are provided. The findings reveal that traditional hazard analysis methods based on a chain of directly related failure events or component failures cannot ensure adequate safeguarding for autonomous ships. In contrast, system theoretic process analysis (STPA) is found to be a highly promising hazard analysis technique that fulfils all the evaluation criteria. Thus, possible combinations of the STPA and other hazard analysis methods may be considered in future research.