Capsize risk of intact frigates in irregular seas

Risk analysis provides a rational method for safe design and operation of complex engineering systems. This paper describes the application of capsize risk analysis to the safe design and operation of intact naval frigates. Input probabilistic descriptions of wave conditions and ship operating conditions are combined with time domain simulations of ship motions to determine capsize risk of an intact ship. The maximum roll angle of a ship in an irregular seaway is dependent on the seaway realization, and this effect is included in the risk analysis. Sample calculations for a naval frigate demonstrate application of the risk analysis procedure. Risk analysis results can be used to develop simplified design guidelines for given ship types. In addition, operator guidelines can be developed for minimizing capsize risk.