This paper will describe the design work and conversion work of icebreaker Otso from Baltic icebreaker to Polar class icebrekaer. Paper will include also user experience from the Arctic after the conversion work.

In April 2015 Arctia signed contract with one of the seismic companies which is operating in the Arctic and the conversion project for fulfilling the rules for worldwide trade and Arctic waters started. The schedule was very tight but all the modifications were made in time and the vessel was ready for Arctic operations in July 2015.

In order to increase vessel utilization outside of the Baltic icebreaking season Arctia Offshore have been studied different kind of solutions during the last ten (10) years. Numerous meetings and planning with naval architects, model tests in ice tank and open water tank was made and during the spring 2015 we had final plans what would be required in order to operate icebreaker Otso in the Arctic. Our requirement was that the open water behavior needed to be close to our multipurpose icebreakers Fennica/Nordica and modifications will not reduce icebreaking capability.

Icebreaker Otso was originally designed and classed to operate in the Baltic Sea in first year ice conditions and was not designed to do ocean passages. Using Otso in the Arctic has been restricted by open water characteristic, ice class and trade area (classification) restricted to domestic (Finnish, Baltic Sea) waters.

Modifications were performed by Rauma Marine Constructions at Rauma Shipyard and included:

New Flume tank to reduce rolling effect in open water conditions

Steel work in the hull, ice class upgraded

New lifeboats installed for worldwide operations standards

New helicopter deck for client use

New hospital for worldwide operations standards

SOLAS and 5 years docking according to the class regulations

Mezanine deck above the Flume tank was installed

Recycling station installed on Mezanine deck

Our experience is that now after three months operating in NE Greenland that the modifications we made are working. This investment was good example that old vessels can have new life and solutions are working. Cost save was massive compared to new build icebreaker.

This conversion shows that it is possible to increase utilisation of old icebreaker and a vessel can have new life

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