Progress in determining icebreaking performance from model scale tests is being achieved through a better understanding of the underlying processes. Scaling relationships for full-scale and model-scale ice properties are given, and the implications of these for correlating ship data in level ice are examined. The compressive strength of ice is shown to be more important than the elastic modulus in determining the total energy loss in cusp formation, which has important implications for ice resistance. Hull-ice friction results show increased friction under ice crushing conditions, and the importance of modelling ice with the correct density is demonstrated. With increasing concern about navigation in non-level ice conditions, advances in the physical modelling of ridged, rubble, pressured, and snow covered ice are reported. Recent evidence indicates that hydrodynamic forces during propeller-ice interaction can be of the same magnitude as ice forces. Finally, a large amount of work has been carried out on conical structures and numerical approaches used to predict forces on such structures are given.
National Research Council of Canada. Institute for Marine Dynamics