With the advent of podded propulsors finding applications in vessels destined to operate in ice conditions, a need to better understand how these propulsion devices interact with the ice has been recognized. Subsequently, testing has been conducted at IOT on a characteristic model of Azimuthing Podded Propulsors in order that a method of predicting the loads these devices experience, in ice conditions, may be developed. The following report briefly outlines the model Azimuthing Podded Propulsor, the method and extent of testing and some preliminary results for the Global system from testing the unit in pre-sawn level ice, pack ice and open water. The tests were conducted in Tractor and Pusher modes for ice thickness of 60 and 80 mm, depths of cut of 15 and 30 mm, and for a full range of azimuth angles. Preliminary results indicate the mode of propulsion is fundamental in determining the magnitude of Global loads, with Tractor mode providing reduced Global loads. This mode also produces increased thrust and torque developed when compared to the Pusher mode. These results are based on mean loads and further analysis based on maximum loads, and the loads experienced by the propeller shaft and blades will result in a complete analysis on which to base a computational model.
National Research Council of Canada. Institute for Ocean Technology