One year later the finalization of Second Generation Intact Stability criteria (SGISc), there is still the need to validate the robustness and consistency of these criteria as indicated by IMO. Not compliance with a stability criterion cannot be always fixed acting only on the vessel design; also operative considerations are needed in order to reduce the risk level during the navigation. After an introduction to SGISc and rule framework for passenger ships, an application will be carried out. A Ro-Ro pax ferry has been selected as subject of this investigation. Vulnerability levels (i.e. Level 1 and Level 2) are applied in order to assess the compliance of a modern representative Ro-Ro ferry. Moreover, a study about how the environmental conditions may affect the results is undertaken considering different scenario, such as the geographical area or the maximum encountered wave height.