The number of azimuth thrusters configured for ice conditions is constantlyincreasing. This is due to the common tendency of widening the range ofoperation of a particular ship in terms of weather conditions, operating modesand geographical areas to achieve more business opportunities throughout theoperating life of the ship. The other major factor is the large potential foroil and gas in the arctic waters. It is also estimated that the number oficebreakers using azimuth propulsion will increase in the near future as theexisting fleet will be modernized and new vessels are built.
The new PC rules have recently been introduced and that has changed theclassification process significantly. Although being clearly more accurate, thenew rules require much more calculation work and have several parametersrelated to the thruster itself.
A first Azimuth thruster has now been classified according to the new PCrules. The thruster, type UUC 505, was originally classified according to DetNorske Veritas Ice-10 ice class which represents an ice class (at the lighterend) for arctic conditions. The thruster was then subsequently classifiedaccording to Det Norske Veritas PC4 ice rules.
The purpose of this presentation is to highlight the practical issues andthe increased workload that the new PC rules have brought on to theclassification process. Also it will highlight some points in the rules whereclarification is needed.