Implementation of second generation intact stability criteria into the stability calculation software

Abstract

The Sub-Committee of Ship Design and Construction of International Maritime Organisation (IMO) has undertaken the development of "Second Generation Intact Stability Criteria (SGISC). The intention of the SGISC is to provide a new set of rules covering those phenomena which is not properly covered by present Intact Stability Code 2008. SGISC is additional rules that complement present rules. Five failure modes will be address in SGISC are excessive roll in dead ship condition, pure loss of stability, broaching involving loss of maneuverability in following quartering seas, parametric roll, and excessive acceleration. Moreover, these criteria are structured in three levels namely, first level, second level and direct assessment. Specific operational guidelines is added as a sort of "fourth level", in the acknowledge that not all dangerous situation can be avoided only by design prescriptions. In this particular study, it was investigated if and how an existing and extensively used commercial code, in the present case, General HydroStatics (GHS ®), could handle level 1 and level 2 criteria. Open source ship models were tested to evaluate the vulnerability of the ship to the SGISC. Finally an illustrative example is presented to verify whether the existing and future regulations can prevent certain obviously dangerous situations on naval ship operating in extreme weather.