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HMS Thames (N71)

Diesel-Electric Attack Submarine

HMS Thames (N71)

Diesel-Electric Attack Submarine


HMS Thames led a short operational career prior to and during World War 2, lost to a mine in the summer of 1940.
National Flag Graphic
ORIGIN: United Kingdom
YEAR: 1932
SHIP CLASS: Thames-class / River-class
SHIPS-IN-CLASS (3): HMS Thames (N71); HMS Severn (N57); HMS Clyde (N12)
OPERATORS: United Kingdom

Unless otherwise noted the presented statistics below pertain to the base HMS Thames (N71) design. Common measurements, and their respective conversions, are shown when possible.
CREW: 61
LENGTH: 345 feet (105.16 meters)
BEAM: 28.2 feet (8.60 meters)
DRAUGHT: 15.1 feet (4.60 meters)
PROPULSION: 2 x Admiralty diesel engines developing 10,000 horsepower; 2 x Electric motors developing 2,500 horsepower; 2 x shafts.
SPEED (SURFACE): 22 knots (25 miles-per-hour)
SPEED (SUBMERGED): 10 miles-per-hour (12 miles-per-hour)
RANGE: 6,952 nautical miles (8,000 miles; 12,875 kilometers)

6 x 21" (533mm) torpedo tubes (bow-facing) (12 x torpedo reloads).
1 x 4" Mk XII deck gun


Detailing the development and operational history of the HMS Thames (N71) Diesel-Electric Attack Submarine.  Entry last updated on 6/30/2017. Authored by Staff Writer. Content ¬©
HMS Thames led the new Thames-class (also "River-class") of attack submarines appearing during the early part of the 1930s for the British Royal Navy. Originally envisioned as a class of 20-strong, the requirement devolved to just three boats - HMS Thames, HMS Severn and HMS Clyde. The type was originally intended for long-range, ocean-bound patrolling as well as surface fleet work and thusly speed became an important design quality. Thames was laid down by Vickers-Armstrong at Barrow-in-Furness and launched on February 26th, 1932. The class was completed with its third boat arriving in 1934.

Thames was given a conventional diesel-electric propulsion system utilizing a pair of Admiralty-designed diesel engines developing up to 10,000 horsepower. This was coupled to 2 x electric motors for 2,500 horsepower output. Diesels propelled the boat during surface work while the electric system governed undersea actions. As with other boats of the period, Thames was required to surface to recharge her batteries, take on new oxygen stores and expel dangerous CO2 gasses. Indeed, much of their running lives was actually spent on the surface where speed and endurance were both dramatically increased when compared to undersea work (quite the opposite of submarine capabilities today).

To manage the speed requirement, HMS Thames was given lighter weight diesels, a smaller-caliber deck gun and special lighter diesel fuel. This helped to promote improved operating speeds - a key component in keeping up with the British surface fleet - though the surface fleet requirement was eventually lessened to the point that Thames became primarily a long-range patrol vessel charged with hunting enemy ships. The speed of the British surface fleet had advanced to capabilities beyond what any submarine of the period could manage.

As built, Thames was given a length of 345 feet, a beam of 28.2 feet and a draught of 15.10 feet. She proved wider than the preceding K-class and some six feet shorter. Displacement was 2,165 tons when surfaced and 2,680 tons when submerged. Her profile was conventional with a sail arranged at amidships, a well-contoured bow and a stern containing the twin screws and rudder control. Performance specifications included a surfaced speed of 22 knots with a submerged speed of 10 knots. Her entire complement numbered 61 and her armament consisted of 6 x 21" (533mm) torpedo tubes in bow-facing positions (with 12 x reloads) and a single 4" Mk XII deck gun. There were no stern-facing torpedo tubes in the design - a feature seen in many wartime submarines.

During 1939, HMS Thames operated in British home waters. World War broke out in Europe with the German invasion of Poland in September and Thames operated as part of the 2nd Submarine Flotilla. Her primary sorties saw her undertaking various patrols in search of German targets - primarily raiders and enemy submarines - and this led her to waters off of Norway as Germany looked to conquer the Scandinavian nation during the April-June Norwegian Campaign of 1940. She managed to sink the Luchs, a German torpedo boat during July though her operational career was rather short-lived. While operating with the 9th Submarine Flotilla later that year, Thames is believed to have struck a mine and as lost with all hands sometime in July or August of 1940. Thus ended the career of HMS Thames.