Stability and Complicated Rolling Responses of Ships in Regular Beam Seas

An analytical procedure is presented for the prediction of the stability and complicated responses of a vessel rolling in regular seas. The effectiveness of the technique is demonstrated by considering unbiased and biased ships rolling in regular beam seas, where the relative waveslope and the frequency of encounter can be alternatively changed. The procedure generates bifurcation diagrams showing the regions of the parameter space where instabilities and deterioration of seaworthiness occur so that the designer can assess the dangers and overall seaworthiness of the craft under a variety of sea conditions.