Oslo-class frigate

TheOslo-class frigate is aRoyal Norwegian Navy frigate design of the 1960s, based on theUS Navy Dealey-class destroyer escorts. The forward hull was customized to suit Norwegian sea conditions better (higherfreeboard) and several sub-systems were European built.^[1] Ships of the class operated until 2007, when they were replaced by theFridtjof Nansen class.

Class overview
Stavanger
Name	Oslo class
Builders	Navy Main Yard,Karljohansvern,Horten,Norway
Operators	Royal Norwegian Navy
Preceded by	River class
Succeeded by	Fridtjof Nansen class
Built	1964–1966
In commission	1966–2007
Completed	5
Lost	1
Retired	3
Preserved	1
General characteristics
Type	Frigate
Displacement	1,735 long tons (1,763 t) standard 2,100 long tons (2,134 t) full load
Length	96.6 m (316 ft 11 in)
Beam	11.2 m (36 ft 9 in)
Draft	5.5 m (18 ft 1 in)
Propulsion	Twin steam boilers, one high pressure and one low pressure steam turbine, 20,000 hp (14,914 kW)
Speed	25knots (46 km/h; 29 mph)
Range	3,900 nmi (7,200 km; 4,500 mi) at 15 kn (28 km/h; 17 mph)
Complement	120 (129 max) officers and men
Sensors and processing systems	Siemens/Plessey AWS-9 long range air search radar Racal DeccaTM 1226 surface search radar in I band Kongsberg MSI-90(U) tracking and fire control system Raytheon Mk 95; I/J-band search and track radar for Sea Sparrow Medium frequencyThomson-CSF Sintra/Simrad TSM 2633 combined hull and VDS active sonar High frequency Terne III active sonar
Electronic warfare & decoys	4 ×Mark 36 SRBOC chaff launchers ESM: AR 700 suite
Armament	2 × 3 in (76 mm) cannon 1 ×Bofors 40mm/70 anti-aircraft gun 2 × 20 mmRheinmetall anti-aircraft guns 2 × 12.7 mm anti-aircraft guns 6 ×Penguin SSMs (usually not mounted) 1 × 8-cellRaytheon RIM-7M Sea Sparrow Mk 29 SAM system 6 ×Kongsberg Terne ASW rocket-thrown depth charges 2 × triple 324 mm (12.8 in)Mark 32 torpedo tubes (Sting Ray torpedoes)

Construction

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All ships were built at the Navy Main Yard inHorten,Norway between 1964 and 1966. The construction of the vessels was part of the Navy rebuilding program, approved by the Norwegian government in 1960. Half of the project expenses were funded by theUnited States as a part of theMutual Defense Assistance Program (MDAP) (a program that ran from when it was passed by theCongress in October 1949 until 1967–68).

Modernization

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In the late 1970s, the class received new armament, most notablyPenguin,RIM-7 Sea Sparrow andMark 32 torpedo launchers. Another modernization was carried out in the 1980s.

During 1995 and 1996, after HNoMSOslo experienced an engine failure, and subsequently sank after sailing in heavy weather, the rest of the class was once again modernized. The hulls were strengthened, which in turn increased the displacement with 200 tonnes.^[1]

All of theOslo class are now retired, with HNoMSNarvik preserved as a museum ship. TheOslo class were replaced by theFridtjof Nansen-class frigates. This replacement started in mid-2006.

Ships

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Five frigates of this class were built. All of them were modernized during the period 1987–1990. They bear the prefixKNM (Kongelig Norske Marine, meaningRoyal Norwegian Navy) in Norwegian andHNoMS (His Norwegian Majesty's Ship) in English.

Name	Pennant number	Launched	Commissioned	Decommissioned
Oslo	F300	17 January 1964	29 January 1966	Sank in 1994
Bergen	F301	23 August 1965	22 June 1967	3 August 2005
Trondheim	F302	4 September 1964	2 June 1966	June 2006
Stavanger	F303	4 February 1966	8 December 1967	June 1998
Narvik	F304	8 January 1965	30 November 1966	1 August 2007^[2]

Oslo

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Oslo in the North Atlantic, October 1971

The lead ship,Oslo, ran aground nearMarstein island on 24 January 1994. One officer was killed in the accident. The next day, on 25 January, she was taken under tow. She sank on the same day in Korsfjorden outside Steinneset inAustevoll county.

Stavanger

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Stavanger was decommissioned in 1998. She was later used fortarget practice and sunk in 2001 by a single DM2A3torpedo launched from theUla-class submarineUtstein (S 302).

Bergen

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Bergen in itsnamesake city for the last time before being decommissioned in 2005.

Bergen was decommissioned in August 2005. Now in use as a targetship.

Trondheim

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On 17 March 2006 at 20:10CET,Trondheim ran aground off Lines island inSør-Trøndelag. No injuries among the 121-man crew were reported. The incident was reported from the ship itself, and at 20:30 it came loose again. Water flooded two compartments (paint storage and forward pump room) of the ship. The compartments were sealed and three ships were sent to assist the frigate.^[3] The frigate was towed to port in Bergen by the coast guard vesselNoCGV Tromsø.^[4]

HNoMSTrondheim was used after decommissioning as a target ship. On 5 June 2013, she was severely damaged in a test of the Norwegian-designedNaval Strike Missile system off the coast of the island ofAndøya.^[5]