Icebreakers as such have been sailing for some 120 years. At first they were just a bit stronger than ordinary commercial vessels. Propulsion solution was steam engines connected to propeller. During the first decades not much development took place. As the marine diesel engines started to replace the steam engines and advances in electric devices took place, first diesel-electric icebreakers were built in the 1930ies. During the next 40 years this solution became more or less a standard for such ships. Next step was the development of the electric drive itself. New smaller AC-motors gave room for new thinking and podded drives came into the picture in the early 1990ies. Simultaneously there were also development exercises on mechanical devices like CP-propellers and Z-drives during 1970ies and −80ies. Today we have available and most commonly used; traditional fixed pitch propellers with conventional shaft lines, mechanical Z-drives and podded drives, all driven by electric motors. The operational profile and mission of the vessel will dictate how the icebreaker will be furbished. This paper discusses the development history of icebreaker propulsion.

Recently there have been delivered and designed new icebreakers, icebreaking shuttle tankers and LNG carriers. Many of these vessel concepts are relying on podded propulsion system. AZIPOD propulsion has been selected to many of these vessels as it provides excellent ice performance for the vessel, good torque characteristics for the propeller and there already exists proven track record of ice operations. This paper will outline important design considerations when developing diesel-electric podded propulsion system.

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