As public concern for maritime safety grows, there is a pressing need to delve deeper into the root causes of maritime accidents and develop effective preventive strategies. Spatial-temporal analysis stands out as a powerful approach to pinpointing accident hot spots. While previous research has shed light on the spatial aspects of these incidents, a comprehensive understanding of their temporal dimensions remains elusive. This paper bridges this gap by leveraging the Space-Time Cube tool in conjunction with traditional Kernel Density analysis to chart the spatial-temporal dynamics of maritime accident hot spots. Focusing on the East China Sea, a region notorious for its high incidence of maritime accidents and home to numerous world-class ports, we present a case study that offers fresh insights. Data spanning from 1994 to 2020, sourced from the Lloyd’s List Intelligence (LLI) database, reveal the evolving landscape of maritime accidents in the area. Notably, since 2005, the Yangtze River Delta Region in China has emerged as a persistent hot spot for accidents, underscoring its significance in maritime safety discourse. Furthermore, our analysis from the 2010s detects a new hot spot expanding towards the southwest of Kaohsiung Port, China, signaling a burgeoning area of concern for maritime safety. While the Fujian coast of China has seen its share of accidents, it is not qualified as a hot spot zone. The Space-Time Cube proves to be an indispensable tool in unraveling the progression of maritime accidents, and our findings indicate that maritime accidents in certain areas may not be merely random occurrences but exhibit intricate patterns.

In line with the IMO strategy on the reduction in GHG emissions from ships, many alternative fuels are being studied to phase out fossil fuels. Among these new fuel candidates, ammonia has gained significant attention because of its capability to hugely reduce CO₂ emissions. With the introduction of ammonia as a deep-sea vessel fuel, there are growing concerns about ammonia leakage and its influence on crew, ship, and environmental safety. In this study, an innovative formal safety assessment (FSA) framework integrating a hazard and operability study (HAZOP) and Bayesian network was developed to assess the leakage risks of ammonia fuel storage onboard ships. The proposed risk assessment framework was demonstrated by a case study in which refrigerated ammonia was stored in an independent fuel tank underneath the main deck. Three specific risk control options (RCOs) and their combinations were compared based on the cost–benefit analysis. The results indicate that decision-makers may have the option to execute a risk control option from a cost–benefit perspective. This research provides users of onboard ammonia fuel with an approach for assessing storage and usage hazards and estimating and managing their risks.