Application of Pendulum Theory to a Model of Overturning of a Rectangular Hull

Abstract

This paper reports an experimental study on application of pendulum theory to determine the possibility of overturning of a rectangular hull model. The model was not a hull of a self-propelling ship but was a pontoon used as a non-self-navigating work vessel. The model begins to list when an unbalanced load is applied. It can then either stabilize in an inclined state or continue to overturn, throwing the unbalanced load midway, and finally stabilizing in the inverted position. In a mid-air experiment, this correlation was observed for two motion scenarios: pendulum and rotational motion. The two motions were reproduced by changing the mass of the load. The experimental results closely match those of analysis performed using the Runge-Kutta method. In an experiment in a water tank, the change in the mass of the load applied to the model hull and the effect of buoyancy were considered for analysis. Both experimental results and analytic results exhibited the same tendency for overturning. The validity of our analytical method using pendulum theory was confirmed by the consistency between these relationships.