generator with an output of at 1,500 rpm. While underway, the fuel consumption of the main engines is 42 tons of heavy fuel oil or diesel per day at or 30 tons per day at , giving the vessel an operating time of 45 to 67 days depending on the speed. During dynamic positioning operations the fuel consumption is 15 tons per day and the operating time depends on the distance and speed of transit to location. In late 2011 the fuel system was converted for the use of ultra-low-sulfur diesel. Fennica is propelled by two Aquamaster US ARC 1 Z-drive azimuth thrusters with ducted fixed-pitch stainless steel propellers. The 177-ton thrusters, driven by ABB Strömberg AC/AC propulsion motors rated at 7,500 kW, considerably improve the maneuverability of the icebreaker. This is especially useful during escort and assistance operations in difficult ice conditions when the icebreaker has to operate at close proximity to other vessels at low speeds. When delivered, she was the first large icebreaker to be equipped with such propulsion system and her maneuverability was often described to be superior to older icebreakers with traditional shaftlines and rudders. Together with three 1,150 kW Brunvoll FU-80 LTC-2250 variable-pitch bow thrusters the azimuth thrusters also allow dynamic positioning during offshore operations. The maximum speed of Fennica is in open water. She can maintain a speed of on level ice and operate in continuous motion in level ice up to thick. Her bollard pull is 230 tons. At the time of her delivery, Fennica was the most powerful offshore support vessel in the world. History Development and construction The development of the Finnish multipurpose icebreakers began in the mid-1980s when the Finnish National Board of Navigation launched a project to find secondary uses for the new vessels it was planning to build as a replacement for some of the oldest icebreakers. Until then the Finnish icebreakers had been designed solely for escort operations in ice-infested waters and their specialized hull form was not suitable for open water. As a result the existing icebreakers had an effective operational time of only three to five months per year and spent the summer season moored at Katajanokka in Helsinki. A multipurpose application of the new icebreakers would thus result in a better utilization of the vessels and, assuming they were chartered by a commercial third party during the summer, improve the economics of the