The River class was a class

Ship class

A ship class is a group of ships of a similar design. This is distinct from a ship-type, which might reflect a similarity of tonnage or intended use. For example, the is a nuclear aircraft carrier of the Nimitz class....

 of minesweeper

Minesweeper (ship)

A minesweeper is a small naval warship designed to counter the threat posed by naval mines. Minesweepers generally detect then neutralize mines in advance of other naval operations.-History:...

 built for the British

United Kingdom

The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 Royal Navy

Royal Navy

The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

 in the 1980s, designated Fleet Minesweepers (MSF).

Design

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

Naval mine

A naval mine is a self-contained explosive device placed in water to destroy surface ships or submarines. Unlike depth charges, mines are deposited and left to wait until they are triggered by the approach of, or contact with, an enemy vessel...

 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

Bofors 40 mm gun

The Bofors 40 mm gun is an anti-aircraft autocannon designed by the Swedish defence firm of Bofors Defence...

 on the manually operated World War II

World War II

World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

-era Mark III mounting, and two L7 GPMGs

FN MAG

The FN MAG is a Belgian 7.62 mm general-purpose machine gun, designed in the early 1950s at Fabrique Nationale by Ernest Vervier. It has been used by more than 80 countries, and it has been made under licence in countries such as Argentina, Egypt, India, Singapore, the United Kingdom and the...

.

The concept was refined in the chartered trawlers HMS St David and HMS Venturer

Venturer class minesweeper

The Venturer class minesweepers were naval trawlers converted from fishing trawlers to minesweeper service for the Royal Navy in 1978.There were 2 members of the class: - originally Suffolk Harvester - originally Suffolk Monarch...

, and a total of twelve vessels, all named after British rivers, were constructed by Richards Shipbuilders at Lowestoft

Lowestoft

Lowestoft is a town in the English county of Suffolk. The town is on the North Sea coast and is the most easterly point of the United Kingdom. It is north-east of London, north-east of Ipswich and south-east of Norwich...

 and Great Yarmouth

Great Yarmouth

Great Yarmouth, often known to locals as Yarmouth, is a coastal town in Norfolk, England. It is at the mouth of the River Yare, east of Norwich.It has been a seaside resort since 1760, and is the gateway from the Norfolk Broads to the sea...

 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.

Service history

Upon entering service they joined the 10th Mine Countermeasures Squadron based at Rosyth

Rosyth Dockyard

Rosyth Dockyard is a large naval dockyard on the Firth of Forth at Rosyth, Fife, Scotland, owned by Babcock Marine, which primarily undertakes refitting of Royal Navy surface vessels.-History:...

 and eleven were assigned to various Royal Naval Reserve

Royal Naval Reserve

The Royal Naval Reserve is the volunteer reserve force of the Royal Navy in the United Kingdom. The present Royal Naval Reserve was formed in 1958 by merging the original Royal Naval Reserve and the Royal Naval Volunteer Reserve , a reserve of civilian volunteers founded in 1903...

 (RNR) divisions around the United Kingdom. The twelfth, , entered service with the regular Royal Navy. Following defence cuts, and were paid off in 1991 and were laid up at Portsmouth

HMNB Portsmouth

Her Majesty's Naval Base Portsmouth is one of three operating bases in the United Kingdom for the British Royal Navy...

. 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, , and were subsequently assigned to the Northern Ireland Squadron where they replaced Ton-class

Ton class minesweeper

The Ton class were coastal minesweepers built in the 1950s for the Royal Navy, but also used by other navies such as the South African Navy and the Royal Australian Navy...

 vessels patrolling the province's waterways and participating in counter-terrorist operations in support of the British Army

British Army

The British Army is the land warfare branch of Her Majesty's Armed Forces in the United Kingdom. It came into being with the unification of the Kingdom of England and Scotland into the Kingdom of Great Britain in 1707. The new British Army incorporated Regiments that had already existed in England...

 and the Royal Ulster Constabulary

Royal Ulster Constabulary

The Royal Ulster Constabulary was the name of the police force in Northern Ireland from 1922 to 2000. Following the awarding of the George Cross in 2000, it was subsequently known as the Royal Ulster Constabulary GC. It was founded on 1 June 1922 out of the Royal Irish Constabulary...

 (RUC). replaced , the last Ton-class vessel in service, as the Dartmouth Training Ship in 1994. Ultimately, the entire class was sold to overseas navies.

Ships

Ship	Commissioned	RN / RNR Use	Fate
(M2003)	12 July 1984	South Wales Division RNR -	Sold to Bangladesh Bangladesh Bangladesh , officially the People's Republic of Bangladesh is a sovereign state located in South Asia. It is bordered by India on all sides except for a small border with Burma to the far southeast and by the Bay of Bengal to the south... BNS Shapla (M95)
(M2004)	30 September 1984	Severn Division RNR -	Sold to Bangladesh BNS Shaikat (M96)
(M2005)	30 March 1985	Clyde Division RNR -	Sold to Bangladesh BNS Surovi (M97)
(M2006)	7 June 1985	Northern Ireland Division -	Sold to Bangladesh BNS Shaibal (M98)
(M2007)	7 June 1985	London Division RNR - Mersey Division RNR - HMS Eaglet HMS Eaglet (shore establishment) HMS Eaglet is a training centre for the Royal Naval Reserve. It serves Merseyside, North West England and North Wales, HMS Eaglet trains over 300 reservists each year and shares a new building with RMR Merseyside in Liverpool.-History:...	Sold to Brazil Brazil Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people... Amorim Do Valle (H35) buoy tender
(M2008)	5 July 1985	RN Fishery Protection Squadron	Sold to Brazil Benevente (P61) Small patrol corvette
(M2009)	12 October 1985	Wessex Division RNR - NI Squadron	Sold to Brazil Bracui (P60) Small patrol corvette
(M2010)	1 March 1986	Tay Division RNR -	Sold to Brazil Taurus (H36) Coastal survey ship
(M2011)	7 February 1985	Newcastle Division RNR - Dartmouth Training Squadron	Sold to Guyana Guyana Guyana , officially the Co-operative Republic of Guyana, previously the colony of British Guiana, is a sovereign state on the northern coast of South America that is culturally part of the Anglophone Caribbean. Guyana was a former colony of the Dutch and of the British...
(M2012)	19 February 1986	Mersey Division RNR -	Sold to Brazil Garnier Sampaio (H37) Buoy tender
(M2013)	4 April 1986	Forth Division RNR - NI Squadron	Sold to Brazil Bocaina (P62) Small patrol corvette
(M2014)	29 April 1986	Sussex Division RNR - NI Squadron	Sold to Brazil Babetonga (P63) Small patrol corvette