Inland vessel rolling due to severe beam wind: A step towards a realistic model

All the present ship stability regulations include, in some way, the analysis of a ship heeling when exposed to a severe beam wind. Although the scenarios for such stability analysis are (mostly) clear and sound, the methods of the calculation are already outdated. The authors, therefore, aim to contribute to the development of new rules, based on a more advanced probabilistic approach (see [Hofman M, Bačkalov I. Weather criterion for seagoing and inland vessels — Some new proposals. In: Proceedings of international conference on marine research and transportation. 2005. p. 53–62; Hofman M, Maksić I, Bačkalov I. Some disturbing aspects of inland vessel stability rules. Journal of Ship Technology, New Delhi 2006; 2(2): 1–14]). In their previous research, for the sake of simplicity, a single nonlinear differential equation of ship rolling was applied as the basis of the analysis. In the present investigation, a more realistic model of coupled nonlinear roll and sway equations is introduced, and the behavior of inland container vessels due to severe beam gusting wind analyzed. The analysis reveals significant discrepancies of the results obtained by the different models, and shows that previous simplified approach overestimated the risk of flooding. It proves, however, the main conclusions of the earlier investigation concerning the deficiency of the present inland container vessel stability rules.