The Sea Keeping Performance Of3000ton Offshore Patrol Vessel

Sea keeping performance is greatly important to the offshore patrol vessel. If itdoes not work well, the mission cannot be accomplished successfully. Or even worse,the safety of the vessel will be affected. The purpose of the thesis is to study the seakeeping performance of the3000ton offshore patrol vessel and its key factor.The theories of hydrodynamics analysis and wave statistical prediction arereviewed. After that, hydrodynamic analysis software of HydroStar is used to analyzea specified3000ton offshore patrol vessel. Results from computation and model testare compared. The computation result of heave differs a little much from the modeltest result, for part of the wave period. For pitch, vertical displacement of specifiedpoint and the natural period of roll, they match well. Main dimensions and factors of3000ton offshore patrol vessels in service of our country and neighboring countriesare compared and analyzed. Then the displacement，ship length, ship width, draft,block coefficient, GM and variation ranges of target ship are specified. Choose thehull line type for the target ship. Transform the hull line according to the specifiedmain dimensions, factors and the variation range. Then the gravity center for eachhull can be specified according to the KM and the specified GM. Hydrodynamicanalyses are carried out for the transformed hull lines (totally23).According to the result, it can be concluded that variation of the parametersmentioned above, does not affect the natural period of heave and pitch. Heave isaffected to a certain extent. Roll, pitch, vertical displacement and natural period ofroll are affected significantly. The key influencing factor of roll and its natural periodis GM. And the factor of pitch and heave is ship length.