This report presents the results of resistance and propulsion tests in level ice of a roughened 1:20 scale model of the Canadian Coast Guard R-class icebreaker. The test conditions were the same as those previously reported for the smooth model. The present test results and those with the smooth model are compared, as are the results obtained at all facilities participating in the comparative study proposed by the Committee on Performance of Ships in Ice-Covered Waters of the International Towing Tank Conference. Keywords: Icebreaker; Ice resistance; Model tests; Propulsions.

This report presents the results of resistance and propulsion tests in level ice of a 1:20-scale model of the R-class icebreaker of the Canadian Coast Guard. On the basis of the model test results, full-scale performance is predicted and compared with available full-scale trials data. Predicted ice resistance and required propeller rpm, thrust and delivered power are lower than full-scale measurements. This disagreement was attributed to the fact that the ship model had a much lower ice friction coefficient than the prototype. On the other hand, predictions of thrust and power for a given ship speed and propeller rpm are in good agreement with corresponding full-scale measurements.

Describes towing tests in ice with the Canadian Coast R-Class Icebreaker. The results indicate that the flexural strength of ice has very little influence on the ice resistance of this particular icebreaker.