Ship stability control in terms of steady-turning heel angle

Abstract

Object and purpose of research. This paper discusses existing approaches to ship stability assessment in terms of steady-turning heel so as to justify the calculation procedure for its initial metacentric height. Subject matter and methods. The study relies on available literature discussing steady-turning heel calculation. It analyses current calculation expressions estimating initial transverse stability in terms of steady-turning heel angle. It has been established that so far this estimate has not been substantiated by any reliable procedure, and the literature on this topic contains a number of inaccuracies and even errors. Main results. The study presents analytical calculation expressions for initial transverse metacentric height of ship in terms of its steady-turning heel. It confirms that calculations have to be performed with a more accurate value for Z-coordinate of hydrodynamic force application point. Conclusion. The procedure developed under this study enables fast monitoring of ship stability and Z-coordinate of its CG in terms of steady-turning heel angle.