The River class, or Thames class were a class of submarines built for the 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...

.

They were the last attempt by the Admiralty

Admiralty

The Admiralty was formerly the authority in the Kingdom of England, and later in the United Kingdom, responsible for the command of the Royal Navy...

 to produce "Fleet Submarines" that is submarines fast enough to operate as part of a fleet which at the time meant being able to manage somewhere around 20 knots (39 km/h) while surfaced. The previous attempts had been the steam powered K class submarine

British K class submarine

The K class submarines were a class of steam-propelled submarines of the Royal Navy designed in 1913. Intended as large, fast vessels which had the endurance and speed to operate with the battle fleet, they gained notoriety, and the nickname of Kalamity class, for being involved in many accidents....

s and the large 12 inches (305 mm) gunned M class submarines

British M class submarine

The British Royal Navy M-class submarines were a small class of diesel electric submarine built during World War I. The unique feature of the class was a 12-inch gun mounted in a turret forward of the conning tower.-Background:...

.

A design was drawn up in the late 1920s and three vessels were built by Vickers

Vickers

Vickers was a famous name in British engineering that existed through many companies from 1828 until 1999.-Early history:Vickers was formed in Sheffield as a steel foundry by the miller Edward Vickers and his father-in-law George Naylor in 1828. Naylor was a partner in the foundry Naylor &...

 in Barrow, Thames

HMS Thames (N71)

HMS Thames was an ocean-going type of submarine of the River Class. She was built by Vickers Armstrong, Barrow and launched on 26 February 1932. She was completed on 14 September 1932, and after commissioning was assigned to the Mediterranean, stationed at Malta.-Service history:She had a short...

 in 1932, Severn

HMS Severn (N57)

HMS Severn was an ocean-going type of submarine of the River Class. She was built by Vickers Armstrong, at Barrow, and launched on 16 January 1934. She was completed on 12 January 1935.-Construction:...

 and Clyde

HMS Clyde (N12)

HMS Clyde was an ocean-going submarine of the River Class. She was built by Vickers Armstrong, Barrow and launched on 15 March 1934. Building was completed on 12 April 1935.-Service history:...

 in 1935. The latter were a little larger than Thames. Initially 20 were planned but changes in thinking and cost limited the building to just the three.

The design compromised on diving depth to keep weight down and speed up. They had a safe diving depth of some 300 feet (91.4 m) compared to the Odin class

Odin class submarine

The Odin class submarine was a class of nine submarines developed and built for the Royal Navy in the 1920s. The prototype was followed by two ships originally ordered for the Royal Australian Navy, but transferred to the RN in 1931 because of the poor economic situation in Australia, and six...

 before them which had managed 500 feet (152.4 m). They were powered by two diesel engine

Diesel engine

A diesel engine is an internal combustion engine that uses the heat of compression to initiate ignition to burn the fuel, which is injected into the combustion chamber...

s delivering 8,000 bhp. Two Ricardo

Ricardo

Ricardo is the Portuguese and Spanish cognate of the name Richard. Therefore the name means "Brave Ruler".-People with the first name Ricardo:*Ricardo Arona, Brazilian mixed martial artist*Ricardo de Araújo Pereira, Portuguese comedian...

 engines drove generators that supercharged the diesels up to 10,000 bhp. This gave them a surface speed of 22 knots (43 km/h).

During the Second World War they initially operated in the North Sea

North Sea

In the southwest, beyond the Straits of Dover, the North Sea becomes the English Channel connecting to the Atlantic Ocean. In the east, it connects to the Baltic Sea via the Skagerrak and Kattegat, narrow straits that separate Denmark from Norway and Sweden respectively...

 and Mediterranean.

Thames was lost off Norway on 23 September 1940. Clyde was used to deliver supplies to the besieged island of Malta

Malta

Malta , officially known as the Republic of Malta , is a Southern European country consisting of an archipelago situated in the centre of the Mediterranean, south of Sicily, east of Tunisia and north of Libya, with Gibraltar to the west and Alexandria to the east.Malta covers just over in...

 in September 1941. Severn and Clyde were in service in the Far East when they were taken out of service in mid to late 1945.

Ships

• HMS Thames (N71)
  HMS Thames (N71)
  HMS Thames was an ocean-going type of submarine of the River Class. She was built by Vickers Armstrong, Barrow and launched on 26 February 1932. She was completed on 14 September 1932, and after commissioning was assigned to the Mediterranean, stationed at Malta.-Service history:She had a short...
  
  
• HMS Severn (N57)
  HMS Severn (N57)
  HMS Severn was an ocean-going type of submarine of the River Class. She was built by Vickers Armstrong, at Barrow, and launched on 16 January 1934. She was completed on 12 January 1935.-Construction:...
  
  
• HMS Clyde (N12)
  HMS Clyde (N12)
  HMS Clyde was an ocean-going submarine of the River Class. She was built by Vickers Armstrong, Barrow and launched on 15 March 1934. Building was completed on 12 April 1935.-Service history:...