Maritime Autonomous Surface Ships (MASSs) incorporate advanced digital technologies, thus rendering their systems more complex and diverse than those of conventional ships. Furthermore, the operation of MASSs, which introduces new risks not encountered in conventional ship operations, differs significantly from that of conventional manned vessels. These challenges highlight the necessity for a more systematic and structured approach to risk analysis and control. This study presents a qualitative risk assessment methodology to identify and manage hazardous scenarios associated with MASS operations systematically. The key feature of the proposed methodology is the integration of cognitive model-based functional analysis with the widely adopted hazard identification (HAZID) method, which enables a structured and comprehensive analysis process. Functional analysis is used to examine the functions required for MASS operations and to analyze interconnected systems to fulfill these functions. Subsequently, HAZID is performed to identify hazardous scenarios that may cause functional degradation or failure. To illustrate the proposed methodology, a case study is presented based on a qualitative risk assessment conducted in preparation for the field trial of an Autonomous Navigation System. Practical applications, including the presented case study, demonstrated the effectiveness of this methodology as a systematic tool for identifying and evaluating potentially hazards in MASS operations.

The flight deck of aircraft carriers in operation is exposed to fire risks which must be mitigated by fire safety measures such as firefighting and suppression systems. To develop advanced fire safety measures, the quantitative risk assessment and management is essential, where fire hazards must be identified in a probabilistic manner considering operational conditions (e.g. sortie generation rates) and site-specific ocean environmental conditions (e.g. humidity, wave and wind profiles). In this paper, a set of realistic fire scenarios on the flight deck of a hypothetical short take-off/vertical landing (STOVL) type aircraft carrier are selected, which shall be used for the quantitative fire risk assessment and management. Potential fire hazards are formulated as a function of random parameters associated with operational and ocean environmental conditions, and probabilistic sampling technique is used to select hundred fire scenarios. Fire exceedance diagrams are established in association with fire-impacted (leak) area through the selected fire scenarios.