MSV Nordica is a Finnish multipurpose icebreaker and offshore support vessel. Built in 1994 by Finnyards in Rauma, Finland, and operated by Arctia Offshore, she and her sister ship Fennica were the first Finnish icebreakers designed to be used as escort icebreakers in the Baltic Sea during the winter months and in offshore construction projects during the open water season.
When Botnica was sold to Port of Tallinn in 2012, Nordica became again the newest icebreaker in service in Finland until the delivery of the new icebreaker, Polaris, in 2016.
Design
General characteristics
The maximum overall length of Nordica is and her length between perpendiculars is . The hull has a moulded breadth of and depth of . Her draught varies between as a Baltic icebreaker and in Arctic conditions and offshore work.Vapalahti, H: Finnish illustrated List of Ships 1999. Judicor Oy, 1999. The gross tonnage of Nordica is 9,392, net tonnage 2,818 and deadweight tonnage ranging between 1,650 and 4,800 tons depending on the draft. The ship weighs 7,935 tons and has a maximum displacement of 12,800 tons.
Nordica is classified by Det Norske Veritas with a class notation 1A1 POLAR-10 Icebreaker Tug Supply Vessel SF HELDK EPR E0 DYNPOS-AUTR. Her ice class, POLAR-10, means that her hull is strengthened for unassisted operation in the Arctic, sub-Arctic and Antarctic regions, where the vessel can encounter winter ice with a nominal thickness of , pressure ridges, multi-year ice floes and glacial ice inclusions. The additional class notation "Icebreaker" states that she has no limitations for repeated ramming.Ships for navigation in ice, Pt.5 Ch.1 Sec.4 A303 . Det Norske Veritas, January 2005. To improve the maneuverability of the ship in ice her hull is wider at the bow than in the stern. These "reamers" increase the width of the ice channel and reduce friction between the hull and ice. The reamers are designed so that they create minimum additional resistance in the astern mode by breaking ice downwards.Soininen, H., Nyman, T., Riska, K., Lohi, P., & Harjula, A. (1993). The ice capability of the multipurpose icebreaker "Fennica" - Full scale results. In POAC 93 - The 12th International Conference on Port and Ocean Engineering under Arctic Conditions: Proceedings Volume 1 (pp. 259-271). POAC Proceedings. In addition the forward part of the hull has explosion-welded stainless steel ice belt that reduces friction and protects the steel plates from abrasion.
The aforementioned design with the maximum breadth in the foreship and a narrower hull aftship, provides the multipurpose vessel also good seakeeping characteristics. Traditionally icebreakers have had, due to their broad beam and relatively shallow hull, a very short roll period in waves, which makes working on board the vessel extremely difficult due to its violent motions.Tellefsen, T., Hagelstam, L. (1993). Development of multipurpose icebreaker and offshore construction vessel. In POAC 93 - The 12th International Conference on Port and Ocean Engineering under Arctic Conditions: Proceedings Volume 1 (pp. 280-289). POAC Proceedings. In the design phase of the vessel, the seakeeping characteristics of the multipurpose icebreaker were defined to be at least as good as those of existing offshore vessels in the North Sea.Karppinen, T., Eronen, H., Lohi, P., Koivumäki, E. (1995). Seakeeping design of the new Finnish multipurpose icebreaker. In PRADS 95 - The 6th International Symposium on Practical Design of Ships and Mobile Units. Proceedings. The offshore operator set a requirement of acceptable acceleration figures at various locations of the vessel at zero speed. The vessel had to be able to operate at least 80% of the time in the North Sea in the summer and autumn season plus have a roll period longer than 10 seconds. The solution with narrow breadth in the aftship results in a sufficiently long roll period. At the midship and aft ship area there are also exceptionally wide bilge shelves as an integral part of the hull, to further dampen the rolling. Moreover, the vessel is equipped with a U-shaped semi-active anti-rolling tank across the widest point of the bow section. The good seakeeping characteristics are an asset also in Arctic operations and long transit distances.Harjula, A., Eronen, H. (1994). MSV Fennica, new operational profile for an icebreaker. ICETECH '94, the Fifth International Conference on Ships and Marine Structures. Proceedings.
For offshore construction projects, Nordica is equipped with a Hydralift active heave compensated crane capable of lifting 30 tons at a radius of or 160 tons at . She also has a smaller MacGregor crane capable of lifting 5 tons at . The vessel can also be equipped with a 120-ton A-frame for trenching machines and ploughs. Nordica has a helipad and can accommodate 48 workers in addition to the ship's crew. Before her helipad was rebuilt in 2012, she also had a small hangar capable of accommodating one helicopter for ice reconnaissance. Since Nordica acts as an escort icebreaker during the winter season, she is also equipped with a Aquamaster-Rauma anchor handling and towing winch, and stern notch for assisting merchant ships. The oblique bridge maximizes visibility from the starboard side steering position.
Power and propulsion
Nordica has a diesel-electric propulsion system with four main generators. She has two twelve-cylinder Wärtsilä Vasa 12V32D and two sixteen-cylinder 16V32D four-stroke medium-speed diesel engines driving Strömberg alternators, the former producing and the latter each. The main engines are also equipped with exhaust gas economizers. In late 2011 they were also retrofitted with catalytic converters and urea spraying systems to reduce NOx emissions in order to meet the strict EPA requirements.Significant reduction in the flue gas emissions of Fennica and Nordica . Arctia Shipping, 24 October 2011. Retrieved 13 December 2011 While designed according to the power plant principle in which the main generators produce power for all shipboard consumers either directly or through a motor-generator, Nordica has one auxiliary diesel generator that can be used to produce electricity when the ship is at port. The four-cylinder Wärtsilä Vasa 4R22 4-stroke medium-speed diesel engine has an output of at 1,000 rpm. In addition she has a twelve-cylinder Caterpillar 3412 DISA emergency diesel 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.Vessel specification: Nordica. Arctia Shipping. Retrieved 22 October 2011 In late 2011 the fuel system was converted for the use of ultra-low-sulfur diesel.
Nordica is propelled by two Aquamaster US ARC 1 Z-drive azimuth thrusters with ducted fixed-pitch stainless steel propellers. The 177-tonOjalehto, M. Potkurilaitteen ylä- ja väliosan kustannusten muodostuminen. Opinnäytetyö, Satakunnan Ammattikorkeakoulu, 2009. 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.Aquamaster-Rauma To Deliver Second Set Of Azimuthing Thrusters For Finnish Icebreaker Program. Maritime Reporter, August 1992. Page 22. Retrieved 22 October 2011Kauhanen, E. Jäät päreiksi, sitten kesätöihin . Tiede 7/2003. Retrieved 22 October 2011 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 Nordica 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 234 tons.
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 state-owned fleet.Tellefsen, T.P. Development of multipurpose icebreaker and offshore construction vessel. Design and Operation of Ships and Offshore Structures - Proceedings of the 1st International Conference Vol 1, pp. 221-231. WIT Press, 1993.Lohi, P. Multipurpose icebreakers for the Finnish National Board of Navigation. Design and Operation of Ships and Offshore Structures - Proceedings of the 1st International Conference Vol 1, pp. 233-240. WIT Press, 1993.
However, the concept did not become reality until the early 1990s, when the Norwegian company Ugland Offshore AS (later DSND Offshore AS) became involved in the project to develop and construct multipurpose icebreakers that could be used for offshore operations in the oil fields during the summer months. The concept was developed by the Board of Navigation together with a Finnish consulting engineering company ILS.Sjöström, P-E. From the North Sea to the Arctic: Finstaship combines icebreaking and offshore . Scandinavian Shipping Gazette, 18 October 2006. The summer period operational profile of the vessel was defined by the offshore markets' needs. Most of all, there was a demand for vessels that could conduct flexible pipe and cable laying and trenching and ploughing of cables and pipelines. Other defined tasks were e.g. cable repair work, anchor handling and the moving of offshore oil drilling platforms, semi-submersible units, and other offshore units, and transportation of deck cargo.
An extensive series of both seakeeping and ice model tests was performed during the design phase of the vessel. Open water model testing was performed in VTT Technical Research Centre of Finland's tank, and the results indicated that the vessel would be able to operate at least 90 % of the time in the North Sea in the summer and autumn seasons, and able to keep the speed of in the area's head seas, also 90 % of the same seasons. Comparative tests were run with a conventional large supply ship model, and they showed that the new icebreaker hull design would function better than a typical large supply ship in normal operating conditions.VTT Technical Research Centre of Finland. Ship Laboratory. Seakeeping Performance Assessment of the Finnyards Multipurpose Icebreaker by Model Tests and Operability. LAI-1210/1992.