MSV Botnica is a multipurpose offshore support vessel and icebreaker built by Finnyards in Rauma, Finland in 1998. She was the newest and technically most advanced state-owned icebreaker of Finland until 2012, when she was sold to the Port of Tallinn, Estonia for 50 million euro. Botnica is used as an escort icebreaker in the Baltic Sea during the winter months and she carries out subsea and offshore construction works worldwide during the open water season.
Design
General characteristics
The maximum overall length of Botnica is and her length between perpendiculars is . The hull has a moulded breadth of and depth of . The draught is when the ship is acting as an icebreaker and in offshore supply operations. The gross tonnage of Botnica is 6,370, net tonnage 1,911 and deadweight tonnage 2,890 tons. The light displacement of Botnica, i.e. the weight of the ship without consumables, cargo and crew, is 5,880 tons. Her loaded displacement varies according to the loading condition.Vessel specification: Botnica . Arctia Shipping. Retrieved 22 October 2011Tekniset tiedot . Arctia Oy. Retrieved 3 August 2011
Botnica is classified by Det Norske Veritas with a class notation 1A1 ICE-10 Icebreaker SF HELDK RPS E0 DYNPOS-AUTRO DK(+) HL(1.8). Her ice class, ICE-10 Icebreaker, means that she is designed to break ice up to thick without limitations to ramming.Ships for navigation in ice, Pt.5 Ch.1 Sec.4 A303 . Det Norske Veritas, January 2005. To improve the ship's maneuverability 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 hull has an explosion-welded stainless steel ice belt that reduces friction and protects the steel plates from abrasion at the waterline. The hull is coated with low-friction Inerta 160 epoxy paint.
The ship's design, with the maximum breadth in the foreship and a narrower hull aftship, provides this multipurpose vessel with 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. 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.
Overall, the design provides the vessel with excellent icebreaking capability combined with the necessary stability, seaworthiness and low motions for offshore work.WÄRTSILÄ Encyclopedia of Marine and Energy Technology | Icebreaker/offshore vessel BOTNICA. Retrieved 23 November 2021
For offshore construction projects Botnica was built with a 160-ton Hydralift ASA crane, but it was replaced in 2010 with a 150-ton MacGregor crane with active heave compensation. The vessel can also be equipped with an optional 120-ton A-frame. The aft deck can be used for various purposes and the ship has a moon pool for underwater operations. In addition the ship has a helipad and accommodation for 45–47 workers in addition to the ship's crew, which is increased from 19 to 23 during the summer season.MSV Botnica . Arctia Oy. Retrieved 3 August 2011 Since Botnica acts as an escort icebreaker during the winter season, she is also equipped with a 210-ton Aquamaster-Rauma towing winch and stern notch for assisting merchant ships.Monitoimimurtaja Botnica on avustanut jo kymmeniä aluksia jäistä . Suomen Merimies-Unioni SMU ry. Retrieved 16 October 2011 The oblique bridge maximizes visibility from the starboard side steering position.
Power and propulsion
Botnica is powered by six engine-generator-engine sets consisting of twelve Caterpillar 3512B V12 high-speed diesel engines, each with an output of , driving six ABB generators. The ship was originally designed for six bigger Wärtsilä generating sets, but the lower initial acquisition cost of the Caterpillars resulted in the very unusual engine arrangement. While having a large number of smaller engines increases the flexibility and efficiency of the power system — engines can be started and stopped on demand and the running engines operate at maximum efficiency — the main engines of Botnica require considerably more maintenance hours in comparison to ships with fewer generating sets. The fuel consumption of the main engines at maximum draught is 50 tons of marine diesel oil (MDO) per day at full power, 25 tons at a service speed of , 10–15 tons during dynamic positioning and 4 tons at port.
Designed according to the power plant principle in which the main engines produce power for all shipboard consumers, Botnica has no separate auxiliary generators. However, there is a smaller six-cylinder Caterpillar 3406 as an emergency diesel generator with an output of .
Botnica was one of the first icebreakers to be equipped with Azipod propulsion, ABB's brand of electric azimuth thrusters developed in Finland. The two 5 MW Azipod VI1600A units considerably improve the maneuverability of the icebreaker — the tactical diameter of the turning circle in open water is less than the overall length of the ship. 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. Together with three 1,150-kW Brunvoll FU-80-LTC-2000 variable-pitch bow thrusters the azimuth thrusters also allow dynamic positioning during offshore operations. The bow thrusters are not used in ice.
The maximum speed of Botnica is in open water and she can maintain a speed of in ice. The maximum ice thickness in which the vessel is capable of maintaining constant speed is . Her bollard pull is 117 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 and the contract for the construction of the first vessel with an option for a sister ship was signed with Finnyards in October 1991. The second vessel was ordered in June 1992.Sjöström, P-E. From the North Sea to the Arctic: Finstaship combines icebreaking and offshore . Scandinavian Shipping Gazette, 18 October 2006. Retrieved 11 October 2011 The ships had large open aft decks similar to platform supply vessels and their two 7,500 kW diesel-electric Aquamaster Z-drive azimuth thrusters provided dynamic positioning capability. The first Finnish multipurpose icebreaker, Fennica, was delivered in 1993 and her sister ship, Nordica, in the following year.
The third multipurpose icebreaker Botnica was designed mainly for Gulf of Finland escort icebreaking. Its summer tasks were planned in cooperation with DSND Offshore AS, and the discussion led to the conclusion that this type of vessel could be used as a cost-effective alternative to semi-submersible platforms for North Sea operators. The new light well intervention and slim hole drilling tasks brought in extra safety requirements, including explosion proof main deck arrangement and A-class bulkhead against deckhouse and lifesaving equipment because of a blow out risk. The vessel was designed into highest redundant DP class, with also machinery, thruster and DP control rooms divided into two independent spaces. A moon pool was designed in the vessel already in an earlier stage of the design, and among needed special equipment was e.g. a removable derrick. Other summer period offshore tasks included e.g. ROV support, hoisting of umbilicals, and offshore construction tasks.Harjula, A., Siirilä, T.K., Eronen, H., Lohi, P. (1999). Multipurpose icebreaker MSV Botnica, basic design aspects. In POAC 99 - The 15th International Conference on Port and Ocean Engineering under Arctic Conditions. Proceedings, vol.2, pp.568-577.
In February 1997 the Finnish National Board of Navigation signed a contract worth FIM 303 million with Finnyards for the construction of a new multipurpose icebreaker. While initially only FIM 280 million was reserved for the new icebreaker, this was later increased by FIM 23 million as the planned vessel proved to be more expensive than expected. While an open call for bids was arranged by the Board of Navigation as dictated by the European Union rules, only Finnyards and Kværner Masa-Yards, another Finnish shipyard, sent in their tenders, and Finnyards won the contract because of shorter delivery time. The new multipurpose icebreaker was to be delivered in March–April 1998.Finnyards sai jäänmurtajatilauksen . Kauppalehti, 7 February 1997. Retrieved 10 October 2011 Also designed by ILS, the new vessel resembles the older Finnish multipurpose icebreakers, but is slightly smaller, less powerful and has open-propeller Azipod units instead of Aquamasters with ducted propellers as the latter had proved to be problematic in ice.Offshore & Icebreaking . ILS Oy. Retrieved 7 October 2011
The new multipurpose icebreaker was given the name Botnica and delivered to the Finnish National Board of Navigation in June 1998, slightly late of the original schedule. Until the recent delivery of the new icebreaker/tug Ahto, Botnica was the newest icebreaker to be commissioned in Finland.
Career
Finland (1998–2012)