New trends in intact ship stability criteria development – The case of first level vulnerability

During the 52nd Session of the Sub-Committee on Stability and Load Lines and on Fishing Vessel Safety (SLF) held at IMO in January 2010, the following specifications for the new generation intact stability criteria have been agreed: - Vulnerability Level 1 should consist in formulae or simple procedure based on geometry / hydrostatics, load condition and basic operational parameters, with low complexity and high safety margins; - Vulnerability Level 2 should consist in simplified physics-based calculations with reduced computational efforts and straight forward application following suitable guidelines, with moderate complexity and safety margins; - Direct assessment (third level) should be based on the best “state-of-the-art” concepts available. Assessment is expected to be made using a probabilistic measure to evaluate safety level. High complexity and low safety margins are expected. In this paper the submitted methodologies in terms of first level vulnerability criteria for the different failure modes will be critically reviewed and the results of a research conducted on some missing ones will be reported.