Purse seine fishing vessel almost has more serious roll motions in rough sea due to its transverse lateral hauling feature. In this paper, we focus on a fishing vessel in beam waves and make a comprehensive stability analysis by using the nonlinear dynamic theory, including series model tests. Accordingly, the safety of ship in beam wave and crosswind are analyzed according to the Multi-scale method and Melnikov approach. A series of roll tests for one tuna purse seine ship are implemented for validation of our results under the regular waves and irregular long-crest waves, according to sea state V and VI.
Recently, the ship stability and safety problems become more serious problems, as the new ship type, large-scale vessel and high-speed ships increase significantly. Only limited information is available on this subject. In particular, the events concerning sea accidents constantly occur. For capsizing problems related with the loss of transverse, therefore, the further study in extreme condition is important and necessary. For the ocean purse seine vessels, as expected, there're many variety of fishing equipments, characterized with heavy. They are often piled on the deck of the ship. One problem is with the effects of the gravity position. Also, the transverse lateral hauling feature could lead to heavy roll more easily, especially even more serious in rough weather. Consequently, the above factors should be fully considered in ship design stage, especially in the case involving the beam wave, which can ensure good transverse stability for the fishing vessel. The ship rolling motion involves the complex nonlinear and chaos phenomena. Within the context of the rolling motion of nonlinear dynamic model, various theoretical models in the literature have been applied for achievement of this particular problem, e.g. the differential dynamical system theory, bifurcation theory and chaos theory of various methods.
