Analytical method to determine the environmental impact on the stability safety of a bulk carrier navigating in the Maritime Silk Road

Since the proposal of the "21st Century Maritime Silk Road", countries and regions along the route have been interconnected in various fields. The continuously improving maritime transportation facilities and equipment have guaranteed the efficient development of the regional economies along the route. However, the current traffic safety situation of the Maritime Silk Road continues to face challenges. Natural conditions and geographical environment are important factors that influence the safety of ship navigation and the efficient operation of shipping routes. The stability safety of ships is subject to the dual constraints of the ship's stowage status and external wind and wave conditions. The natural conditions of navigable waters are complex and variable, and it is imperative to understand the marine climate and weather change characteristics of the route. To measure the impact of wind and wave factors on the rolling risk of ships during navigation, an analytical method to determine the environmental impact on stability safety of ship navigation is proposed.

A data processing framework for wind and wave environmental factors along the Maritime Silk Road was established based on the Kriging interpolation technology and the adaptive weighted average method. Combined with 22 years of meteorological data in the sea area, a navigation risk map for the key waters of the Maritime Silk Road was developed. Based on quantitative analysis of the influence of wind and wave environmental factors on ship heeling, the heeling risk index for evaluating ship stability safety was proposed. According to the model reconstruction of typical ship capsizing accidents, the impact of external wind and wave factors on ship stability safety was revealed.

The results reveal the following: (1) The risk is high in the South China Sea, medium in the Arabian Sea, and low in the Bay of Bengal. (2) The navigation environment of the Maritime Silk Road route is significantly affected by typhoons: (a) During the typhoon season, there are high risks in the East China Sea and the South China Sea from June to August, as well as in the Arabian Sea from March to May. (b) During the nontyphoon seasons, due to the influence of monsoons and cold air, winds and waves increase. High risks appear in the Yellow Sea, the East China Sea, and the Bay of Bengal from November to December and January. (3) Based on the constructed environmental impact model for ship stability safety, the waters near the Gulf of Aden and the Strait of Malacca exhibit significant narrow tube effects, indicating a significant level of high navigation risk. Special attention should be given to the wind and wave conditions in the above sea areas to ensure the stability safety of ships. (4) According to the analysis of accident cases, when the heeling risk index is between 0.5 and 0.8, it is important to assess the heeling risk as early as possible and prepare for emergency deployment in a timely manner. When the heeling risk index is in the range of 0.8-1.1, emergency deployment should be implemented. When the heeling risk index is>1.1, evacuation should be performed in a timely manner to ensure human safety. Further comparative analysis of similar cargo transportation cases was conducted, and the impact of the internal environment of ships on ship stability safety was discovered, verifying the fundamental role of ship attributes and cargo performance in ensuring ship stability. Particularly, the stability of cargo behavior is as important as the navigation environment and should be included in the stability safety impact system of ships.

This study provides a reference for establishing a Maritime Silk Road traffic stability safety system with navigation safety and resilience as the core.