Stability and Subdivision
Intact stability
Intact Stability Code
IMO has long developed intact stability criteria for various types of ships, culminating in the completion of the Code on Intact Stability for All Types of Ships Covered by IMO Instruments (IS Code) in 1993 (resolution A.749(18)) and later amendments thereto (resolution MSC.75(69)). The IS Code included fundamental principles such as general precautions against capsizing (criteria regarding metacentric height (GM) and righting lever (GZ)); weather criterion (severe wind and rolling criterion); effect of free surfaces and icing; and watertight integrity. The IS Code also addressed related operational aspects like information for the master, including stability and operating booklets and operational procedures in heavy weather.