The behavior of the double-bottom structure of a ship stranding on a rock is studied to establish the analytical method for the strength. An experiment is performed by using a model of the double-bottom structure of approximately 1/7 scale and a rock model of a cylindrical shape. An analysis using the idealized structural unit method shows a good agreement with the experimental result.
A general analytical method to determine the strength of a ship at a stranding condition is proposed. An example calculation is performed for a cargo ship being about 120 m long and stranding on a rock with a cone shape. Furthermore, the nonlinear behavior of a girder element with a manhole is idealized for actual ships and the validity of the idealization is confirmed by an experiment.
