Prediction of bow door loads in extreme wave conditions

Selected results of the European research project DEXTREMEL are presented with emphasis on extreme wave loads on the bow door of a RoRo passenger ferry. To predict these loads, two numerical procedures were applied. The first procedure comprised linear seakeeping prediction, computation of impact pressures coefficients by means of a finite volume code, and a time domain analysis to predict the force on the bow door. The second procedure comprised linear seakeeping prediction and water entry computation of tilted bow sections with a boundary element code. In addition to computations, model tests were carried out in a seakeeping basin. Measurements comprised local pressures at the bow and forces on the bow door. A laser-based measurement technique visualized wave contours ahead of the bow. Effects of ship speed, wave height and bow flare angle were investigated. Numerical predictions were compared with measurements and rule based design loads.