River class minesweeper

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For other naval ship classes of the same name, see River class.

River-class minesweeper
General characteristics
Displacement:	850 tons standard / 890 tons full
Length:	47 metres
Beam:	10.5 metres
Draught:	3.1 metres
Propulsion:	2 shafts, Ruston 6RKC diesels, 3,040 bhp
Range:
Speed:	max. 14 knots
Complement:	5 officers / 23 ratings (accommodation for 36: 7 officers / 29 ratings)
Armament:	*1 x Bofors 40mm gun Mark 3 2 x 7.62 mm GPMGs

The River class was a class of minesweeper built for the British Royal Navy in the 1980s, designated Fleet Minesweepers (MSF).

The Rivers were built with a traditional steel hull to a design based on a commercial offshore support vessel. The class was designed to be operated as deep sea team sweepers, to combat the threat posed to submarines by Soviet deep-water buoyant moored mines codenamed Cluster Bay.

The River Class MSF was equipped with the Wire Sweep Mark 9 (WS 9) which was capable of performing Extra Deep Armed Team Sweeping (EDATS). Operating in pairs (or a number of pairs in formation), they towed a sweep between the two ships that followed the profile of the bottom and cut the mooring wires of the mines; these released mines would then be destroyed on the surface with gunfire. The WS 9 was able to be used for mechanical sweeping in this manner or influence sweeping whereby a transducer was towed through the water generating noise, both acoustic and electro-magnetic, that simulated a larger high value unit. The Rivers were also armed with a single 40 mm Bofors gun on the manually operated World War II-era Mark III mounting, and two GPMGs.

The concept was refined in the chartered trawlers HMS St David and HMS Venturer, and a total of twelve vessels, all named after British rivers, were constructed by Richards Shipbuilders at Lowestoft and Great Yarmouth at an approximate unit cost of £4.6 million. The class was designed to operate in deep water and ocean environments, if necessary for long periods of time without support. The complement was 5 officers, 7 Senior Ratings, and 16 Junior Ratings, although additional accommodation meant that a total crew of 36 could be borne for training purposes.

Upon entering service they joined the 10th Mine Countermeasures Squadron based at Rosyth and eleven were assigned to various Royal Naval Reserve (RNR) divisions around the United Kingdom. The twelfth, Blackwater, entered service with the regular Royal Navy. Following defence cuts, Helmsdale and Ribble were paid off in 1991 and were laid up at Portsmouth. Further cuts followed when the future of the RNR was reviewed in 1993 and as a result the entire class was withdrawn from RNR service.

Blackwater, Spey, Arun and Itchen were subsequently assigned to the Northern Ireland Squadron where they replaced Ton-class vessels patrolling the province's waterways and participating in counter-terrorist operations in support of the British Army and the Royal Ulster Constabulary (RUC). Orwell replaced Wilton, the last Ton-class vessel in service, as the Dartmouth Training Ship in 1994. Ultimately, the entire class was sold to overseas navies.

[edit] Ships

HMS Orwell seen here in the Bay of Biscay en route to Gibraltar, 1990

Ship	Commissioned	RN / RNR Use	Fate
Waveney (M2003)	12 July 1984	South Wales Division RNR - HMS Cambria	Sold to Bangladesh BNS Shapla (M95)
Carron (M2004)	30 September 1984	Severn Division RNR - HMS Flying Fox	Sold to Bangladesh BNS Shaikat (M96)
Dovey (M2005)	30 March 1985	Clyde Division RNR - HMS Graham	Sold to Bangladesh BNS Surovi (M97)
Helford (M2006)	7 June 1985	Northern Ireland Division - HMS Caroline	Sold to Bangladesh BNS Shaibal (M98)
Humber (M2007)	7 June 1985	London Division RNR - HMS President Mersey Division RNR - HMS Eaglet	Sold to Brazil Amorim Do Valle (H35) buoy tender
Blackwater (M2008)	5 July 1985	RN Fishery Protection Squadron	Sold to Brazil Benevente (P61) Small patrol corvette
Itchen (M2009)	12 October 1985	Wessex Division RNR - HMS Wessex NI Squadron	Sold to Brazil Bracui (P60) Small patrol corvette
Helmsdale (M2010)	1 March 1986	Tay Division RNR - HMS Camperdown	Sold to Brazil Taurus (H36) Coastal survey ship
Orwell (M2011)	7 February 1985	Newcastle Division RNR - HMS Calliope Dartmouth Training Squadron	sold to Guyana
Ribble (M2012)	19 February 1986	Mersey Division RNR - HMS Eaglet	Sold to Brazil Garnier Sampaio (H37) Buoy tender
Spey (M2013)	4 April 1986	Forth Division RNR - HMS Claverhouse NI Squadron	Sold to Brazil Bocaina (P62) Small patrol corvette
Arun (M2014)	29 April 1986	Sussex Division RNR - HMS Sussex NI Squadron	Sold to Brazil Babetonga (P63) Small patrol corvette