Numerical investigation of the vertical response of a containership in large amplitude waves

The symmetric distortions of a containership in large amplitude waves are analyzed by means of numerical methods and are compared with experimental results. The study is part of a ISSC-ITTC benchmark study which was intended to analyze the accuracy of the numerical methods and the uncertainty involved with the predictions of the ship responses. In this paper the numerical calculations are carried out by means of a body nonlinear time domain method. The time domain code is coupled with a finite element model and the ship hull is modeled as a non-uniform Timoshenko beam. The experiments were conducted in a wave tank with an aluminum back bone and the flexible responses of the ship were measured. The ship was tested in regular waves of moderate to large amplitude to analyze the effect of nonlinear springing. Even though a slight discrepancy is found between the numerical and the experimental vertical motions in large amplitude waves, the numerical vertical bending moments are in reasonably good agreement with the experimental results.