Stability criteria evaluation and performance based criteria development for damaged naval vessels

Abstract

The current quasi-static damage stability criteria used by the UK MoD are largely based on the Sarchin and Goldberg work published in 1962. These criteria ensure a level of stability performance after damage. Like the intact stability criteria, the inherent level of safety in these criteria and the link to the dynamic performance of the vessel in waves is little known. A methodology has been developed to evaluate the dynamic stability performance of naval vessels after damage. The evaluation of the current criteria has been performed using a large number of time-domain ship motion simulations using a computer program capable of simulating a damaged vessel with subsequent water ingress and flooding. This gives an insight into the level of safety inherent in the current damage stability standards. A selection of damage cases were conducted using a frigate hullform with geometric variations made to the internal subdivision. A range of loading conditions from those passing the current criteria through to those failing in each of the geometric damage case variations were systematically assessed in a range of wave conditions representative of post-damage sea states. The results from the dynamic study were then compared to the current damage stability criteria terms to identify how the current criteria relate to the dynamic damage performance in waves. © QinetiQ Limited 2010, by permission of QinetiQ Limited.