Alta-class minesweeper

The Alta class is a ship class of minesweepers operated by the Royal Norwegian Navy. An almost identical class of minehunters is known as the Oksøy class.

Norwegian Alta-class minesweeper Rauma (M352)
Class overview
Name	Alta class
Builders	Kværner Mandal, Mandal, Norway
Operators	Royal Norwegian Navy
In commission	1996–present
Completed	5
Active	3
Lost	1
Retired	1
General characteristics [1]
Type	Minesweeper
Displacement	375 tonnes[2]
Length	55.2 metres
Beam	13.6 metres
Height	21 metres
Draught	2.5 metres
Propulsion	2 × 2.7 MW (3,621 hp) MTU 12V 396 TE84 diesel engines 2 × Kværner water jets
Speed	30 knots (56 km/h; 35 mph)
Range	1,500 mi (2,400 km)
Complement	32
Sensors and processing systems	Oropesa mechanical sweep Kongsberg Defence & Aerospace (KDA) Agate (Air Gun and Transducer Equipment) acoustic minesweeping system Elma magnetic sweepers
Armament	1 × Sadral surface-to-air missile system 1 or 2 × Rheinmetall 20 mm AA guns 2 × 12.7  mm machine guns

Design

The Alta class was built by Kværner Mandal during 1996 and 1997, while the related Oksøy class was built in 1994 and 1995. A total of nine vessels were built, five minesweepers and four minehunters. The catamaran hull is built in a fibre-reinforced plastic sandwich of very low magnetic signature.^[3]

Two large fans located on each side create an air cushion between the two hulls and a front and aft rubber skirt, lifting the vessel, giving small drag and a high cruise speed, as well as low susceptibility to the shock of exploding mines since only a small portion of the hull is actually exposed in the water. Propulsion by water jet, again one in each hull, gives a low acoustic signature. A degaussing system gives the vessels extremely low electromagnetic signature.

Ships

Alta class[4]
Number	Name	Builder	Commissioned	Status	KNM Orkla burning outside Ålesund, Norway in November 2002
M350	Alta	Kværner, Mandal	12 January 1996	Scrapped some time prior to 23 July 2022[5]
M351	Otra		8 November 1996
M352	Rauma		2 December 1996
M353	Orkla			Destroyed by fire on 19 November 2002[6]
M354	Glomma		1 July 1997	Sold 2009[7]

Service history

Orkla was destroyed by fire on 19 November 2002.^[6] Glomma is no longer in active service. Alta was scrapped along with the Oksøy class M341 Karmøy prior to 23 July 2022