Stochastic Nonlinear Rolling: Which Approach?

A review of the work done in the last years in deterministic, “quasi deterministic” (bifurcations and chaos) and stochastic nonlinear rolling is presented. Difficulties, shortcomings and open problems are presented. In particular, indications are given regarding the approach to the stochastic rolling taking into account the main nonlinearities of the system and of the excitation. It appears that the approach is completely different depending on the degree of nonlinearity introduced in the term describing the excitation. Different versions of exact or approximate analytical methods can be applied in the case of linear sea, whereas slight departures from linearity can be accounted by the method of bispectrum. Only mixed statistical experimental approaches can actually be applied when the sea is strongly nonlinear (asymmetric and breaking waves).