Preliminary 3D rendering of the Pohjanmaa class
Class overview
NamePohjanmaa-class corvette
BuildersRauma Marine Constructions
Operators Finnish Navy
Preceded by
Cost1.3 billion euro (estimate for 4 ships)[1]
Built2023–2025 (planned)[2]
In commission
  • 2028– (planned)
  • 2029– (current estimate)[3]
On order4
Building1[4]
General characteristics [1][5]
TypeCorvette[6]
Displacement4,300 tons[2]
Length117 m (383 ft 10 in)[2]
Beam16 m (52 ft 6 in)
Draught5 m (16 ft 5 in)
Ice class1A[5]
Installed power
Propulsion
Speed26 knots (48 km/h; 30 mph)
Range3,500 nmi (6,500 km; 4,000 mi)
Endurance14 days[2]
Complement73[2]
Sensors and
processing systems
  • Saab 9LV combat management system (CMS)
  • Saab Sea Giraffe 4A FF AESA 3D radar
  • Saab Sea Giraffe 1X short-range 3D radar
  • 2 × Saab Ceros 200 radar and optronic tracking fire control directors
  • Dual-tow Patria Sonac DTS sonar
  • Kongsberg SS2030 hull-mounted sonar
  • Kongsberg SD9500 sonar
Electronic warfare
& decoys
Armament
Aviation facilitiesHelideck and hangar

The Pohjanmaa class is a series of four multi-role corvettes[6][9] currently under construction for the Finnish Navy as part of the Squadron 2020 (Finnish: Laivue 2020) project. Together with the existing four Hamina-class missile boats, the four new surface combatants will form the backbone of the Finnish Navy from the mid-2020s onwards. They will replace seven older vessels that have been or are due to be decommissioned; the minelayer Pohjanmaa, two Hämeenmaa-class minelayers and four Rauma-class missile boats.

Design

General characteristics

The overall length of the Pohjanmaa-class corvettes will be 117 metres (383 ft 10 in) and the beam 16 metres (52 ft 6 in). The maximum draught of the vessels will be 5 metres (16 ft 5 in) which corresponds to a displacement of about 4,300 tonnes (4,200 long tons).[2] With these main dimensions, the new multi-role corvettes will be the largest Finnish surface combatants since the 1930s coastal defence ships Ilmarinen and Väinämöinen.[10] Each ship will have a complement of about 70 officers and crew.[1] Designed for year-round service in the seasonally freezing Baltic Sea, Pohjanmaa-class corvettes will feature an ice-strengthened hull and ability to operate independently in ice.[5] Although no Finnish-Swedish ice class exists for military vessels, the ice capacity of the corvettes will be equivalent to that ice class 1A for merchant ships.[5]

The Pohjanmaa class will feature a combined diesel-electric and gas (CODLAG) propulsion system with a total output of 28 megawatts (38,000 hp).[2] During normal patrol operations, the ship's twin ice-strengthened controllable pitch propellers are driven by electric propulsion motors. However, two of the four 12-cylinder MAN 12V175D type diesel generating sets are installed on double resilient mountings within soundproof enclosures to reduce noise and vibration during anti-submarine warfare (ASW) missions.[11] When higher speeds are required, a single General Electric LM2500[12] gas turbine driving both propeller shafts via a common gearbox can be used to achieve speeds in excess of 26 knots (48 km/h; 30 mph).[5][7] For low-speed maneuvering, the ships are fitted with two bow thrusters.[1]

Combat management system, communication system and sensors

The combat management system (CMS) of the Pohjanmaa-class corvettes will be provided by the Swedish defence company Saab. The integrated communication system (ICS) TactiCall is provided by Saab. Built around the 9LV CMS, the system will include Sea Giraffe 4A FF fixed-face AESA and Sea Giraffe 1X short-range 3D radars installed on a Saab Lightweight Integrated Mast (SLIM), two CEROS 200 fire control directors, TactiCall integrated communications system, and a laser warning system.[13][14] Before final selection, the Finnish Navy shortlisted Saab together with Lockheed Martin Canada and Atlas Elektronik as the potential combat management system provider and integrator.[15]

The underwater sensor suite will consist of Kongsberg's SS2030 active hull-mounted sonar and SD9500 lightweight over-the-side dipping sonar.[16] In addition, Pohjanmaa-class corvettes will be equipped with Patria's lightweight dual-tow Sonac DTS that includes both an active variable-depth sonar as well as a passive towed receiving array.[17]

Armament

Pohjanmaa-class corvettes will be armed with a single dual-purpose naval gun, surface-to-surface and surface-to-air missiles, anti-submarine torpedoes, naval mines, close-in weapon systems, and a decoy system.[1][9]

The forward-mounted Bofors 57 mm Mk3 dual-purpose main gun will be recycled from the Hamina-class missile boats.[5] In addition, each Pohjanmaa-class corvette will be fitted with two Saab Trackfire remote controlled weapon stations for close-in self-defence and four Rheinmetall Multi Ammunition Softkill System (MASS) decoy launchers.[14][18]

The primary surface-to-surface armament of the Pohjanmaa class is the Gabriel 5 subsonic anti-ship missile.[19] The latest version of Israel Aerospace Industries's anti-ship missile family was selected over Kongsberg's Naval Strike Missile, MBDA's Exocet, Boeing's Harpoon and Saab's RBS15.[20] In Finnish Navy service, the missile system will be referred to as PTO 2020 (Pintatorjuntaohjus 2020, "surface defence missile").[1]

Against aerial targets, Pohjanmaa-class corvettes will be armed with Raytheon RIM-162 Evolved Seasparrow Missile (ESSM) Block 2[21] surface-to-air missiles. Each vessel will be capable of carrying a total of 32 missiles quad-packed to eight Mark 41 Vertical Launching System silos.[22] In Finnish Navy service, the system will be referred to as ITO 20 (Ilmatorjuntaohjus 20).[1]

For underwater warfare, the vessels will be fitted with Saab Torped 47 lightweight anti-submarine torpedoes.[18] In addition, Pohjanmaa-class corvettes will be able to lay naval mines.[1]

Development and construction

The initial development of the new surface combatants for the Finnish Navy began with a research and planning phase in 2008 and the Squadron 2020 project was officially launched in 2015.[23] The 647.6 million euro shipbuilding contract was awarded to the Finnish shipbuilder Rauma Marine Constructions in September 2019.[24] In November 2021, the shipyard announced that it would need from 6 to 12 months additional time to complete the design.[25] As of June 2022, the estimated delay has reportedly increased to 14 to 18 months.[3][26]

The construction of the lead ship began on 30 October 2023.[4] The first-of-class ship would begin its trials in 2026, and the full construction run would be completed in 2029.[3][2][27]

Naming

One of the Finnish Navy's traditions has been to name its major combat ships after regions in Finland. The name Pohjanmaa, which is the Finnish name for the region Ostrobothnia, has been used both by the Finnish and Swedish navies for previous ships and classes of ships, dating back to the 18th century with the first recorded vessel being Gamla Pojama ("Old Pohjanmaa"), that was launched in 1760, and the last one, being the minelayer/training vessel Pohjanmaa, which was sold in 2016. The aforementioned 18th century Pohjanmaa, alongside the Hämeenmaa, Uusimaa and Turunmaa types were also the four main "archipelago frigate" types used in the 1790 Battle of Svensksund, which is one of the largest Finnish (Finland was a part of Sweden at the time) naval victories and the largest naval battle in the Baltic Sea to date.[28]

Criticism

Classification

While the Finnish Navy[6] and the Ministry of Defence[9] refer to the new surface combatants as multi-role corvettes, several commentators[29][30] have pointed out that by displacement the 4,300-tonne (4,200-long-ton)[2] vessels should be classified as frigates.[Note 1] In late September 2019, shortly after the construction contract was awarded, MP Johannes Yrttiaho (Left Alliance) submitted a written question to the Parliament of Finland about, among other related topics, the classification of the new ships.[31]

In the official blog of the Finnish Defence Forces, Flotilla admiral Jori Harju (Commander of the Finnish Navy) noted that one of the reasons leading to the increased displacement is the additional strengthening of the hull, propulsion shaft lines and propellers required for year-round operation in the seasonally freezing Finnish territorial waters. He also pointed out that the Pohjanmaa class is intended to operate primarily in coastal waters whereas frigates are traditionally considered as the smallest class of warships operating in the high seas as part of a so-called blue-water navy.[32]

Size

Since the early 2000s, Finnish Navy's surface combatant fleet has consisted mainly of fast attack craft with displacements of 250 to 300 tonnes (250 to 300 long tons). Until the planned commission of the new Pohjanmaa class, the largest surface combatants of the Finnish Navy remain the two Hämeenmaa-class minelayers. Several commentators have criticized the Squadron 2020 program due to the size of the new corvettes: according to critics, the ships are too large for the often shallow Finnish territorial waters riddled with skerries as well as too attractive and large targets for Russian anti-ship missiles. Furthermore, it has been speculated that the ship size has been driven by their suitability for international missions rather than domestic defence needs and that the whole concept has been derived from the Freedom-class littoral combat ships operated by the United States Navy.[31][33]

The Finnish Navy has argued that the size of the new ships is a result of combining multiple missions within a single hull. In particular, the ability to lay naval mines has been raised as one of the key features necessitating a larger vessel.[32] Despite some similarities in external appearance to other naval ships, the new multi-role corvettes have been tailored for the Finnish Navy's missions in the Baltic Sea and thus represent a completely new vessel concept with no reference design in service anywhere in the world.[5]

Notes

  1. ↑ Corvettes are traditionally considered as the smallest class of warships with displacement up to 3,000 tons; frigate is the next size category.

References

  1. 1 2 3 4 5 6 7 8 "Tällaisia ovat sotalaivat, joihin Suomi käyttää 1,3 miljardia euroa – "ei ole tarkoitus miinoittaa koko Itämerta"". YLE (in Finnish). 19 September 2019. Retrieved 16 April 2020.
  2. 1 2 3 4 5 6 7 8 9 10 "Pohjanmaa-luokan taistelualusten suunnittelu on loppusuoralla ja tuotanto alkaa tänä vuonna". Merivoimat (in Finnish). 31 March 2023. Retrieved 31 March 2023.
  3. 1 2 3 "Miljardihankkeella vaikeuksia: Merivoimien uudet sotalaivat myöhästyvät yli vuodella". Iltalehti. 30 June 2022. Retrieved 1 July 2022.
  4. 1 2 "Suomen suurimman sotalaivan rakentaminen alkoi Rauman telakalla". Helsingin Sanomat (in Finnish). Sanoma Media Finland. 30 October 2023. Retrieved 30 October 2023.
  5. 1 2 3 4 5 6 7 "Maanpuolustuksen ja turvallisuuden osto-opas 2/2018" (PDF) (in Finnish). Suomen Sotilas. 2018. Retrieved 16 April 2020.
  6. 1 2 3 "Laivue 2020 -hanke korvaa merivoimien poistuvat alukset uusilla" (in Finnish). Finnish Defence Forces. Retrieved 28 September 2019.
  7. 1 2 "Aker Arctic to Deliver Propellers and Shaft Lines for Pohjanmaa-class Corvettes". Naval News. 15 October 2019. Retrieved 16 May 2020.
  8. ↑ "Pohjanmaa-Class Multi-Role Corvettes, Finland".
  9. 1 2 3 "The new multi-role corvettes are the most suitable surface combatants for Finland". Ministry of Defence. Retrieved 28 September 2019.
  10. ↑ "Merivoimille neljä 105-metristä korvettia – 1,2 miljardilla suurimmat alukset sitten panssarilaiva Ilmarisen ja Väinämöisen". Tekniikka & Talous (in Finnish). 17 January 2018. Retrieved 22 February 2019.
  11. ↑ "Finnische Marine entscheidet sich für den MAN 175D-Motor" (PDF) (in German). MAN Energy Solutions. 15 October 2020. Retrieved 15 October 2020.
  12. ↑ "GE to Provide Rauma Marine Constructions with LM2500 Gas Turbines for Finnish Navy's New Multipurpose Corvettes". General Electric. 14 October 2020. Retrieved 14 October 2020.
  13. ↑ "Saab Receives Finnish Squadron 2020 Order". Saab. 26 September 2019. Retrieved 16 May 2020.
  14. 1 2 "Saab provides Finland's new Pohjanmaa corvettes with combat system". Saab. 26 September 2019. Retrieved 16 May 2020.
  15. ↑ "Lockheed Martin Canada shortlisted for Finnish Navy corvette program". Vanguard. 11 April 2017. Retrieved 16 May 2020.
  16. ↑ "Kongsberg to supply Sonar Systems For Finnish Navy Pohjanmaa corvettes". Naval News. 15 April 2020. Retrieved 17 April 2020.
  17. ↑ "Patria to deliver ASW Sonars to new Pohjanmaa class corvettes". EDR Magazine. 23 January 2020. Retrieved 16 May 2020.
  18. 1 2 "Merivoimien korvettitilaus varmistui - hangaarissa drone, taistelujärjestelmä Saabilta". Lentoposti.fi. 19 September 2019. Retrieved 16 May 2020.
  19. ↑ "Merivoimien uusi pintatorjuntaohjus – Gabriel 5" (in Finnish). Merivoimat. 13 December 2019. Retrieved 16 May 2020.
  20. ↑ "Finnish Navy to acquire new Surface-to-surface Missile system". Ministry of Defence. 6 July 2018. Retrieved 16 May 2020.
  21. ↑ "Pohjanmaa-luokan korvetteihin ESSM Block 2 -ohjusjärjestelmä" (in Finnish). Finnish Defense Forces. 5 October 2023. Retrieved 5 October 2023.
  22. ↑ "Merivoimien Pohjanmaa-korvetteihin siilolaukaistavat Evolved SeaSparrow -ilmatorjuntaohjukset (video)". Lentoposti.fi. 21 February 2019. Retrieved 16 May 2020.
  23. ↑ "The Navy's new vessels are projected to be completed in 2027". Finnish Ministry of Defence. Retrieved 2018-04-01.
  24. ↑ "Rauma Marine Constructions and Saab to be main contract partners for Pohjanmaa-class vessels". Ministry of Defence. 19 September 2019. Retrieved 2 March 2020.
  25. ↑ "Pohjanmaa-luokan suunnittelutyö tarvitsee lisäaikaa". Ministry of Defence. 2 November 2021. Retrieved 3 November 2021.
  26. ↑ "RMC:n Mikko Niini ihmettelee, miksi puolustusministeriö hyökkää niin vahvasti telakkaa vastaan – Rauman telakka sinnittelee myöhästyvien laivojen ja tappioiden kanssa". Turun Sanomat. 1 July 2022. Retrieved 2 July 2022.
  27. ↑ Tringham, Kate (2023-04-05). "Finnish Navy gears up to start construction of Pohjanmaa-class corvettes in 2023". Janes. Retrieved 2023-04-05.
  28. ↑ Alm, Mikael (2003). "Teaterkungen på slagfältet". Svenska Krig och Krigiska Svenskar (in Swedish). Lund: Historiska Media: 71.
  29. ↑ "Sanokaa mitä sanotte – fregatti se on..." Suomen Sotilas (in Finnish). 25 September 2015. Retrieved 28 September 2019.
  30. ↑ "HS-analyysi: Merivoimat on saamassa kaikessa hiljaisuudessa suunniteltua suurempia taistelualuksia – miksi Puolustusvoimat on puhunut asiasta vähätellen?" (in Finnish). Helsingin Sanomat. 21 September 2019. Retrieved 28 September 2019.
  31. 1 2 "Kirjallinen kysymys KK 161/2019 vp" (in Finnish). Eduskunta. 26 September 2019. Retrieved 28 September 2019.
  32. 1 2 "Pohjanmaa-luokan korvettien rakentaminen käynnistyy!" (in Finnish). Finnish Defence Forces. 26 September 2019. Retrieved 28 September 2019.
  33. ↑ "IL-analyysi: Suomi aikoo ostaa turhan sotalaivan - Merivoimien himoitsema korvetti on helppo maalitaulu Venäjän ohjuksille" (in Finnish). Iltalehti. 11 December 2016. Retrieved 28 September 2019.
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