Investigations on the Strength of Ships Going in Waves by Model Experiments

Abstract

We can easily suppose the dynamical stress of ships going in waves is far different from the values of statical stress by standard calculation.To solve the problems of dynamical strength of ships in waves especially the problems of slamming and its effect on hull strength, we have tried the experiments in model basin by towing 6 metre model ship, made of brass; and measured deck stress, bottom pressure and pitching, heaving motion of ships.In the present paper, we dealed with the results of the experiments when wave length is equal to ship length, in comparatively light draft, and on various wave heights and ship speeds.By experiments, we found the physical causes which produce slamming, and we defined the range of ship speed at which slamming occurs as the slamming zone.At slamming zone, the impact pressure at ship bottom and impact compressive stress on deck increase remarkably as increase in wave height.We defined the effective wave height ratio by comparing measured stress with calculated ones, and found these values showed a tendency to converge with increase in wave height.