Analysis of the level of stability reserve of inland and mixed (river–sea) navigation vessels

Abstract

During the life cycle of a vessel, its characteristics may change within a certain acceptable range, and operational cases may differ from those regulated. This means that the calculations of seaworthiness and, above all, stability are carried out for the conditional state of the load, which corresponds to the vessel in a finite time interval. The specified deviation can be taken into account either by calculating the stability with the changing characteristics of the vessel, or by entering a stability reserve that considering all standardized and non-standardized factors. The article considers the second approach. For this purpose, domestic, foreign and international requirements for the stability of vessels are analyzed, in which indicators are identified that are responsible for its reserve. According to the developed mathematical model, which takes into account the positive change in displacement and the application of the center of gravity as a result of the peculiarities of the experience of heeling and the presence of water on the decks, the combined effect of circulation, displacement of bulk cargo and dynamic jerk of the stretched tow rope, a numerical experiment was conducted with inland and mixed (river-sea) navigation vessels. Based on its results, a type of stability margin coefficient was developed and recommendations were made to change the main stability criterion so that the ratio of permissible and heeling forces was greater than 1.2.