The ice conditions in Arctic waters are complex and variable, requiring ships to dynamically adjust their routes to ensure safe and efficient navigation. Traditional dynamic path planning algorithms struggle to address the extensive variability of Arctic ice conditions. To tackle this issue, this paper improves the D* Lite algorithm by leveraging the gradual and convergent nature of Arctic ice condition changes. The original algorithm’s local update and path extraction rules are modified to prevent chain updates triggered by minor localized changes, thereby reducing the frequency of updates in non-critical areas. By simulating dynamic route planning for ships in Arctic waters during both the freezing and melting periods, the improved D* Lite algorithm was compared with the original D* Lite algorithm and a global update algorithm in terms of voyage distance, risk coefficient, planning time, and the number of node updates. The computational results demonstrate that the improved D* Lite algorithm achieves planning results very similar to those of the original D* Lite algorithm and the global update algorithm at the lowest update cost, significantly enhancing the safety and efficiency of dynamic route planning for ships in Arctic waters.

Aiming at the structural safety of the offshore wind power installation during a ship’s bottom operation, taking the wind power installation in a certain sea area of the East China Sea as an example. Water was found in the pump room of the Wind Power Installation Vessel during the bottom operation. After inspection, it was found that the ship was obviously arched, the deck was deformed, the right side of the hull had cracks in the front and rear, and the left side of the hull was bulging. According to the different draught depths of the ship, three operating conditions are selected, namely, sitting on the bottom, the highest tide level on the day of incident, and at the time of the incident. Finite element analysis on hull structural strength is carried out to find out the cause of the hull rupture and water flooding in owing to the arch-in-the-ship accident. The calculation results show that due to the large area of scouring on the bottom of the ship, the bottom of the ship is not solid, and with the alternate change of the tide, there are both middle arching and sagging phenomenon on the ship. Hence, the force acting on the ship sitting on the bottom changes periodically, resulting in large local stresses in ship structures, which is the main cause of ship accidents.