Investigation about wave profile effects on ship stability

The influence of wave profile on ship righting arm is among the possible stability failure issues addressed by the recent activity at IMO. The present paper is mainly focused on the so called “pure loss of stability”, a dangerous phenomenon that can occur for specific conditions in following seas. In the paper, the development of a computational tool is described, able to evaluate the influence of wave profile on ship metacentric height and righting arms, giving the possibility to investigate different ship geometries and loading conditions in relation with wave profiles in terms of different lengths and steepness. The tool is applied to several ship typologies and a special attention in the investigations is given to transversal metacentric height GM and to the maximum righting arm GZmax since, in some proposals, these are the parameters assumed as indicative while performing first and second level vulnerability analysis for pure loss of stability.