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Nansen Class Anti-Submarine Warfare Frigates

Discussion in 'Education & Research' started by AbRaj, Jan 6, 2017.

  1. AbRaj

    AbRaj Captain FULL MEMBER

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    Nansen Class Anti-Submarine Warfare Frigates, Norway
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    The five Nansen Class anti-submarine warfare frigates were built by Navantia of Spain for the Norwegian Navy. The vessels are: HNoMS Fridtjof Nansen (F 310), Roald Amundsen (F 311), Otto Sverdrup (F 312), Helge Ingstad (F 313) and Thor Heyerdahl (F 314).

    The first vessel was launched from Navantia's Ferrol shipyard in June 2004. Sea trials of the Nansen with the Aegis weapon system and the new SPY-1F radar began in October 2005. The Nansen was commissioned in Ferrol in April 2006 and arrived in Oslo, Norway in June 2006.

    Launch of the second, Roald Amundsen, was in May 2005 and it was commissioned in May 2007. The Otto Sverdrup (F 312) was launched in May 2006 and commissioned in April 2008. Helge Ingstad (F 313) was launched in November 2007 and commissioned in September 2009.

    "The five Nansen Class anti-submarine warfare frigates were built for the Norwegian Navy."
    The last ship, Thor Heyerdahl (F 314), was launched in February 2009 and commissioned in January 2011. The Nansen Class replace Oslo Class vessels in service since 1966.

    The main contractor is Navantia (formerly Izar) of Spain and the Aegis weapon systems integrator is the US company, Lockheed Martin. The vessels are of modular construction and the completion of the first module of the hull ('keel-stretching') of the Fridtjof Nansen took place in April 2003. Lockheed Martin delivered the first Aegis system in December 2003.

    The main mission of the frigate is anti-submarine warfare and the ship is equipped to detect, identify, track, engage and attack hostile submarines.

    The ship is also equipped for anti-air warfare and anti-surface warfare roles and can carry out non-combatant tasks in peacetime. The ship houses a medical facility.

    Nansen Class frigate design
    The 4,600t ship has five decks and two superstructures. The welded steel, 132m monohull has 13 watertight compartments for enhanced survivability. The hull design is optimised for stability, sea-keeping and manoeuvrability and the hull appendages and propellers are designed for low hydrodynamic noise.
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    The ship has a CODAG propulsion plant which gives a maximum transit speed of 27kt.

    NH90 ASW helicopter
    The ship has a helicopter landing deck and hangar which can support one medium-sized helicopter. Six AgustaWestland Lynx helicopters operated by the Norwegian Air Force are to be replaced by the NH Industries NH90 ASW helicopter on order for the Royal Norwegian Navy.

    The NH90, to be deployed on the Nansen frigates, will have Thales Underwater Systems' flash sonics dipping sonar system and anti-submarine torpedoes.

    AEGIS command and control combat aircraft
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    The integrated weapons system from Lockheed Martin is based on the Aegis combat system from Lockheed Martin and anti surface and MSI 2005F anti-submarine warfare systems from Kongsberg Defence and Aerospace.

    "The Nansen Class ships have a helicopter landing deck and hangar which can support one medium-sized helicopter."
    The Aegis combat system for the Nansen is based on the Spy-1F multifunction phased array radar, a scaled version of the AN/SPY-1D in service on US Navy Aegis cruisers and destroyers. It provides missile and gun fire control functions, simultaneous multiple target tracking, volume radar search and horizon search.

    The phased array radar provides instantaneous beam steering which gives the advantage of vast reaction time against airborne threats.

    Aegis uses two slave illuminators to provide terminal flight guidance for the evolved Sea Sparrow missile. A Sagem Vigy 20 electro-optical and infrared tracker provides passive target tracking.

    Thales was awarded a contract in January 2009 to supply a new SATCOM system for the Nansen frigates, based on the Thales SURFSAT.

    Nansen Class frigate weapons systems
    The ship is armed with two modules each with four launch tubes for the NSM (naval strike missile) long-range anti-ship missile, developed by Kongsberg Defence & Aerospace for the Royal Norwegian Navy. NSM has inertial navigation mid-course guidance with GPS and an imaging infrared terminal seeker. It has a 125kg multi-purpose warhead and a range of 160km. NSM was cleared for series production in June 2007.

    An eight-cell mk41 vertical launch system for the evolved Sea Sparrow missile (ESSM) has the capacity for 32 missiles, four per cell. ESSM has been developed by Raytheon with an international co-operative of ten NATO countries and is designed to counter high-speed anti-ship missiles. It has the same semi-active radar guidance and warhead as the Seasparrow but has a new rocket motor and tail control to provide increased speed, range and manoeuvrability.

    The ship has two twin magazine torpedo launchers for BAE Systems Stingray lightweight torpedoes. One Oto Melara SuperRapid 76mm gun has a rate of fire of 120 rounds a minute.

    ASW sensor suite
    Thales Underwater Systems is prime contractor for the sonar suite with Simrad as a subcontractor. The suite includes the advanced CAPTAS mk2 V1 Combined Active / Passive Towed Array Sonar and the Spherion MRS 2000 hull-mounted sonar providing anti-submarine detection at short, medium and long ranges.

    CAPTAS mk2 V1 includes a low-frequency active towed body, which uses free flooded ring (FFR) technology for transmission, providing a high source level in a compact array. The system has a triplet linear towed receiver array, which provides high definition left / right ambiguity resolution.

    Sonobuoys can also be deployed.

    Reutech Radar Systems RSR210N X-band 2D pulse Doppler radar is fitted for helicopter control and surveillance, under a contract awarded in December 2007.

    Electronic warfare systems and countermeasures
    The electronic warfare suite includes the CS-3701 tactical radar surveillance system (TRSS) from EDO Reconnaissance & Surveillance Systems (formerly Condor Systems Inc). CS-3701 combines precision electronic support measures (ESM) and radar warning receiver (RWR) functions.

    A Terma DL-12T decoy launcher dispenses infrared, radar and acoustic decoys. In March 2005, QinetiQ was awarded the contract to supply the LOKI acoustic torpedo countermeasures, to be deployed from the DL-12T launcher. Deliveries of LOKI to the Royal Norwegian Navy began in December 2007.

    "The frigate has two twin magazine torpedo launchers for BAE Systems Stingray lightweight torpedoes."
    Integrated communications control system
    The ship's internal and external communications are managed by an integrated communications control system from Aeromarine. The communications suite includes tactical data link, link 11, prepared for link 16/22 and for SHF and UHF military satellite communications.

    CODAG propulsion plant
    The propulsion plant is in a CODAG combined diesel and gas turbine configuration, with two Izar Bravo 12V 4.5MW propulsion diesel engines and a GE LM 2500 19.2MW gas turbine.

    A retractable 1MW electric bow thruster provides precise manoeuvrability when the ship is in confined areas. The bow thruster can be used as an auxiliary propulsion unit in an emergency if the main propulsion system is compromised.

    The propulsion system gives a maximum speed of more than 26kt and a cruise speed of more than 18kt. The ship has two shafts with controllable pitch propellers, two rudders and a pair of active stabilising fins.

    The ship's diesel generators are four NTU 396 Series 12V 900kW
     
  2. Fenrir

    Fenrir FULL MEMBER

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    Several of the five ship class do have a single 8-cell VLS armed with either an ASROC variant or ESSM.

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    But not all of the ships in the Fridtjof Nansen Class. Thor Heyerdahl has two 8-cell VLS.

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    The Nansens are significantly larger then their predecessor the Oslo class.

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    Last edited: Jan 7, 2017
  3. AbRaj

    AbRaj Captain FULL MEMBER

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    Impressive ASw capability
    and Surface to air too
     
    Last edited: Jan 6, 2017
  4. Ankit Kumar 001

    Ankit Kumar 001 Captain Technical Analyst

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    Further they were built to accommodate OTO BREDA 127mm and 1 CIWS Systems.

    May be just like Kolkata Class,they will get 127mm at MLU.
     
  5. Ankit Kumar 001

    Ankit Kumar 001 Captain Technical Analyst

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    Query

    After spending a good amount on Aegis System ,why are there no StandardMissile2 MRs ?
     
  6. Fenrir

    Fenrir FULL MEMBER

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    The standard rule of interception states that for subsonic targets a ripple of two missiles is to be used to ensure a +90% kill probability. The same rule states that for supersonic targets a ripple of 6-8 missiles should be fired to ensure the same probability of intercept. This means that a Nansen class frigate would only have four intercepts against subsonic targets and one against a supersonic target if using SM2 versus the smaller ESSM, of which a Nansen can carry 32 versus just 8 SM2 - except Thor Heyerdahl which can carry 16 SM2 or 64 ESSM.

    Unless there is a plan to increase the number of launchers on each ship switching to SM2 would actually represent a step down in each ship's self-defense capabilities versus ESSM.

    Norwegian waters face a limited threat from aerial assault or enemy shipping which is tracked before either leaves their home bases. This helps to limit the necessity of air-defense missiles and allows the ships to concentrate more of their resources on ASW of Surface Warfare.

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    When hostile shipping or aircraft do appear they are immediately hounded by a combination of ground assets such as NASAMS II or NSM, the Royal Norwegian Air Force and the Royal Norwegian Navy who've spotted them coming from hundreds, or even thousands of miles away, depending on the watching eyes. These photos where taken by Norwegian aircraft and ships. Because we are the first-contact point for Russian vessels and aircraft transiting down from the Arctic, we've invested a great deal in our early-warning and detection systems.

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    While the waters around Norge are filled ASW platforms like listening devices, not to mention Norwegian sub-hunters at sea and in the air, submarines have been assessed to be the primary concern of the Royal Norwegian Navy and its vessels, mostly ASW platforms and mine-countermeasures craft reflects this.

    ESSM has been deemed sufficient as a self-defense missile against targets that slip though our screen.

    ...

    The Naval-technology article also leaves out that the Nansens can be armed with depth bombs and mines and have room to fit them with low-cost anti-submarine rockets like the now retired Terne III system.

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    A more modern variant would be used in its place.
     
    Last edited: Jan 7, 2017
    Ankit Kumar 001 likes this.

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