Prediction of Effects of Hull Forms on Seakeeping Qualities of Ships

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Objective of this study is to develop a systematic method for predicting added resistance in waves and safety of a ship under the effects of deck wetting. Such systematic method will be useful for evaluating hull form from its seakeeping qualities. Several methods available do not necessarily serve this purpose. They do not give accurate prediction which reflect correctly the effects of a little difference between hull forms. So we need to develop new methods particularly for added resistance and transient motions leading to capsize under the influence of water on deck, since those have not been fully investigated so far.What we have done in this study are as follows: 1. We presented several experimental data to show clearly bow shape's effect on the unsteady wave pattern generated by a ship running in waves. This effect was described by a new thoretical approach we developed, accuracy of prediction of added resistance when bow shape is blunt is improved considerably by this new method. 2. A simple method was investigated for computing hydrodynamic forces with the finite magnitude effects of motion taken into consideration. 3. We succeeded in providing computer simulation of capsizing when sea water is coming onto deck over bulwark. This simulation program enables us to evaluate the height of bulwark on the safety of ships. 4. 3D panel method in which the boundary condition on the hull surface is accurately satisfied was applied for predicting added resistance even in oblique and following waves. With some improvements in computational technique, this method is useful for eavaluating hull forms with a little difference from the standpoint of added resistance.