The number of azimuth thrusters configured for ice conditions is constantly increasing. This is due to the common tendency of widening the range of operation of a particular ship in terms of weather conditions, operating modes and geographical areas to achieve more business opportunities throughout the operating life of the ship. The other major factor is the large potential for oil and gas in the arctic waters. It is also estimated that the number of icebreakers using azimuth propulsion will increase in the near future as the existing fleet will be modernized and new vessels are built.

In general it will be increasingly important to be able to efficiently configure an azimuth thruster for ice operation. This work has to be done before the actual bidding process since in most cases the specification of ice requirements defines the size of the thruster.

Without clear and user friendly classification rules the definition and bidding of the thruster is difficult or even not possible at all. The main ice loads should be definable using simple formulas that contain only few parameters that are related to the thruster itself. These kind rules are very good for the bidding process and the design of a new thruster since very little iteration is needed.

The new PC rules have recently been introduced and that has changed the processes significantly. Although being clearly more accurate, the new rules require much more calculation work and have several parameters related to the thruster itself. This makes the processes considerably more iterative and thereby more time consuming.

The purpose of this presentation is to highlight the practical issues that the new PC rules have brought on. The intention is not to question the scientific content or correctness of the new rules.

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