Study On Capsizing Characteristic Of Tumblehome Hulls In Waves

The vulnerability criteria on stability under dead ship condition is now under developmentby the International Maritime Organization (IMO). The tumblehome hull attracts IMO’sattentions because as an unconventional ship, its characteristic may make it suffer stabilityfailures and capsizing in waves. Stability of tumblehome hulls in seas can’t be effectivelycalculated and appraised by the conventional method. So the advanced theory of mechanics andmethod of probability become the major technique, with which we can study on capsizingcharacteristic of tumblehome hulls in seas. The major work of the thesis includes:1、 Firstly, the roll motion of tumblehome hull is forecasted numerically by a nonlinear timedomain method considering hydrodynamic variation caused by the hull instant wet surface.The time histories of capsizing are simulated at time domain and the method of predictingcapsizing probability under dead ship condition is established.2、 Model test of the tumblehome hull under dead ship condition is carried out in theseakeeping basin and calculated results are verified by the model test data. The calculatedlarge roll responses are agree well with the test date, which declares the methodestablished in this thesis is effective for predicting tumblehome hull’s large roll motionunder dead ship condition.3、 The capsizing characteristic of the tumblehome hull is investigated, including influencelaw of different sea states and GM values. It indicates that GM values require significantconsideration in the tumblehome hull’s design. Based on the calculated results thesuggested GM value of the tumblehome hull should be larger than1.5meters forpreventing capsizing.