ABSTRACT
With increasing number of azimuthing propulsor installed on ships, azimuthing propulsor ice class rule development for Finnish-Swedish Ice Class Rules (FSICR) started in 2010. In the beginning of the development project, suitable load scenarios for azimuthing propulsors were identified and applicable ice load calculation methods were reviewed. The two main load scenarios for the propulsors were considered to be impact to floating ice block and penetration to ice ridge. The impact load scenario drove the development of a new dynamic impact load model for Azimuthing units. This impact model was tested against small-scale controlled tests on sea ice and also validated with selected full-scale measurements. The ice ridge interaction load scenario was studied with state of the art FE-model of ice ridge and ship interaction. The scientific approaches yielded solid physical background for formulating simplified load estimation formulas for the load scenarios. In addition to the main load scenarios, also impact load distributions were investigated.
The whole project lasted from 2010 to 2016, and it had a steering group consisting of classification societies as well as azimuthing propulsor manufacturers. The work was reviewed and guided with the experts in the steering group. The results of the work are being included as a part of new version of Finnish-Swedish ice class rules.
