Development of a model for global response of ship hull during ramming of heavy ice features

Ice-induced global forces that affect a ship’s hull when colliding with heavy ice features are analysed. The objective was to increase the knowledge of what structural loads a ship encounters during Arctic operations and thereby contribute to safer shipping in the Arctic. In the study, a model was created that used recorded motions of a ship when it collided with a heavy ice feature in order to calculate the global forces that affect the ship hull.The motion data were collected by Det Norske Veritas during the Coldtech research project on board of the Norwegian Coast Guard vessel KV Svalbard. To give an understanding and background to the problems that the model needs to handle, the paper includes a brief review of ice-ship interaction and hull monitoring. The model developed is limited to perpendicular collisions and the first impact sequence, since only then the impact location can be considered as known. The forces resulting from the model are compared with the design loads of ice class rules, since the same impact type is considered. The results are also compared with previous work done in the area. From the comparisons it can be seen that the forces calculated with the current model seem to be reasonable as they are in the same order of magnitude. However, more measurements are required in order to fully verify the model and the measured motions