Designing for damage stability beyond design level

This paper describes the background and provides the rationale and the framework to embrace all feasible measures (passive/design and active/operational – normal and emergencies) for improving the damage survivability of RoRo Passenger ships. The ideas elaborated in the paper is an attempt to elucidate and assess the impact on options for new and existing ships of increasing the required subdivision index R, the former in response to the higher damage stability standards recom- mended following the conclusion of the EMSA III project and the latter in case IMO decided to apply higher damage stability requirements retrospectively, particularly in the aftermath of an accident. Such a framework would provide the motivation for instigating and estab- lishing novel damage stability enhancing paradigms in line with IMO Circular 1455 on equivalents, for alter- native compliance. This, in turn, would enable the industry to focus on all credible measures for damage stability enhancement in case of a flooding accident. This represents a step change both in the mind-set of naval architects and in safety legislation but the impact will be immense and mostly positive. This paper paves the way in this direction by providing the background and rationale for such a framework and by introducing an alternative system for damage stability enhancement that involves injecting highly expandable foam in the compartment(s) undergoing flooding during the intimal post-accident flooding phase thus enhancing damage stability and survivability of RoPax vessels well beyond the design levels in the most cost-effective way currently available. This is a mind-set changing innovation that is likely to revolutionise design and operation of most ship types and RoPax, in particular. A number of applications are considered in the paper for a range of ship sizes with impressive results that will challenge the cur- rent established practice.