The Finnish Transport Infrastructure Agency has launched the Calypso, a new icebreaker concept boat equipped with an innovative hybrid motorised removable bow powered by Danfoss Editron. The icebreaker vessel is currently moored in Mustola harbor in Lappeenranta and has begun operating on Lake Saimaa and the deep waterways of the surrounding area this winter.
The removable bow, the world’s largest motorised of its kind, was delivered by Turku Repair Yard as part of the Winter Navigation Motorways of the Sea II project. The €7.6 million scheme, co-funded by the EU Connecting Europe Facility programme, aims to develop and enhance the maritime winter navigation system and its safety during the winter. One of its key targets was the creation of a motorised icebreaking removable bow concept, which would enable ice-strengthened vessels to be used as icebreakers during the winter. This specific bow is capable of breaking ice up to 70cm thick.
Danfoss Editron’s hybrid-electric system is used for powering the removable bow with two generators, built as a DC system, and two propulsion systems. The company has also provided a front supercapacitor so that peak powers can be efficiently controlled. The EDITRON software also cuts fuel and delivers high efficiencies as the diesel generators in the DC system can be driven at variable speeds. The power plan and propulsion system of the removable bow have been designed to be operated from the pusher tug wheelhouse, while the machinery can operate unmanned.
Kari Savolainen, Project Manager at Danfoss Editron, commented, “We have operations in Lappeenranta, so we can see first-hand how harsh winter conditions directly impact shipping transport. This new kind of removable bow will make the whole industry more efficient and sustainable, as it will enable virtually any kind of tug to become an icebreaker ship. Our EDITRON system is easily adaptable for future optimisations and we are eager to learn more about our supercapacitor’s ability to control the peak powers.”
Juuso Kummala, Industry Line Director at Väylä, added, “Lake Saimaa’s ice is more solid than sea ice and can reach up to 80cm thick. Developing this innovative design concept for the removable bow and equipping it with its own propulsion system will achieve savings in capital costs, as we will charter the pusher for only part of the year. We are also expecting to see savings in fuel consumption thanks to Danfoss Editron’s hybrid propulsion system.”
As winter temperatures in Finland can plummet to -30°C, icebreakers are a necessity even during mild winters. Introducing hybrid electric power in icebreaking operations will help the country meet its target to lower emissions by 40% by 2030 compared to 1990 levels.
The removable bow concept was first unveiled in 2018 and the base unit was constructed in 2019. After outfitting it was finally handed over in December 2020.
The detachable bow is equipped with its own propulsion machinery and is mounted to the tugboat by three-point fixing. The detachable bow has two straight axle lines driven by electric motors. The dimensions of the vessel and bow combination were designed so as to enable effective icebreaking operation in the Saimaa area and the Saimaa Canal.
The pusher tug Calypso, which is owned by Alfons Håkans that is used for operating the detachable bow, has undergone modifications that enable the attachment of the bow.
Although this is the first physical detachable icebreaking unit it is similar in some ways to a concept developed by Aker Arctic and Wärtsilä in 2007 under the name Double Acting Push Pull Barge (DAPPB) which envisaged a pusher barge like arrangement which could utilise a power unit with conventional machinery to push the barge in open waters and a wider icebreaking unit that would use the same attachment system that would pull the barge through ice.
