| Résumé | With an increasing interest in shipping in ice-covered waters, propulsion systems on these vessels are exposed to ice loads, which can be significantly larger than the open water loads. Severe damages can occur if the propulsion system is under-designed. At present rule formulae based on ice torque, which is related to the ice class of the vessel, is used in the design of these systems. The fact that failures continue to happen shows the need to study ice loads on these systems. Hence, at National Research council (NRC) - Institute for Marine Dynamics (IMD) several types of propulsion systems have been tested in ice conditions over the years. Among them are highly skewed propellers and azimuthing podded propellers. This paper describes the capabilities developed at NRC-IMD to test these two different propulsion systems. For the tests for the performance of highly skewed propellers a dynamometer to measure ice loads encountered by an individual blade was designed and built. It is mounted inside the hub and the blade attached to it. It can measure six component loads encountered by the blade. Some sample test results are given in the paper. In a different study, azimuthing podded propellers are being modelled. the experimental model is designed so that ice loads on different locations on the podded system can be measured: blade loads, shaft loads, shaft bearing loads and the global loads on the whole system. a brief description of the system is presented in the paper. |
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