Research on Uprighting Process of a Capsized Ship in Combined Wind and Wave Parameters

At present, most salvage schemes are designed based on the calculation results of ship statics, which is still an empirical method. However, many projects are always affected by the wind and waves, and there is a significant difference between the force situation of ships with wind area and the calculation results of ship statistics. This paper analyzes the methods and tools of righting a capsized ship, establishes the righting force model of a capsized ship in wind and waves in accordance with floatation, stability, righting force, waves and wind, and then derives the method of longitudinal strength calculation. The floating state and stability of a capsized ship in four different sea conditions are calculated by GHS software, and three uprighting schemes are designed based on the number and position of the righting force. According to the size of the wind and waves, this paper simulates the uprighting process of the capsized hull in four cases. According to the results, it found that waves and wind can play a significant role in the uprighting process. Case I could reduce the righting force by 76.2~78.3% more than case III. The wind force moment of case II is about 34% less than that of case I. The size of the waves is negligible to the stability of a capsized ship; however, it also has an impact on the hull loads during the uprighting process. When the winds and waves are large, setting the location of righting force in a proper cross-section can reduce the righting force and hull loads to a certain extent. Through comparative analysis, the paper gives the righting schemes for different cases.