Fleet submarine

A fleet submarine is a submarine with the speed, range, and endurance to operate as part of a navy's Battle Fleet. Examples of fleet submarines are the British K class and the American Gato class. Within the modern Royal Navy, the term is used for the British nuclear powered attack submarines. In the United States Navy, the term came to be used primarily for the long-range submarines that served in World War II.

USS Wahoo (SS-238) off the Mare Island Naval Shipyard, California (USA), on 14 July 1943 (19-N-48937)
Gato class fleet submarine USS Wahoo


United States

The term was used by the United States Navy to distinguish submarines suitable for long range patrols in the Pacific Ocean from earlier classes such as the United States S-class submarines. The initial goal, pursued with frequent interruptions since the AA-1-class (aka T-class) launched 1918-19, was to produce a submarine with a surfaced speed of 21 knots to operate with the Standard-type battleships of the surface fleet.[1] Most of the nine "V-boats" launched 1924-33 (V-1 through V-6) were either attempts to produce a fleet submarine or were long-range submarine cruisers. Eventually, a long range of 11,000 nautical miles (20,000 km) was combined with high speed, beginning with the Salmon-class launched in 1938, to allow sustained operations in Japanese home waters while based at Pearl Harbor.[2] These qualities also proved important in the Pacific commerce raiding of World War II, but the 1922 Washington Naval Treaty's prohibition on unrestricted submarine warfare precluded inter-war planning in this area.[3] Although the Gato-class was considered the fully developed archetype,[4] the earlier Porpoise, Salmon, Sargo and Tambor-classes were incrementally improved prototypes distinctly different from the two contemporary experimental Mackerel-class coastal submarines. The Tambors were fully developed and similar to the Gatos except for diving depth and separation of the engines into two compartments.[5][6]


Japanese I-boats were a conceptually similar long-range differentiation from smaller "medium" or "sea-going" Ro-boats, although some I-boats had features like aircraft hangars and large-caliber deck guns more often associated with submarine cruisers.[7]


In order to get the speeds - over 20 knots while surfaced - required to match their capital ships and to be able to screen ahead of the fleet or flank the enemy, the British initially used steam propulsion. The K-class entering service in 1916 were large for their time. Although able to reach 24 knots the complexity of shutting down boilers and stowing funnels made them slow to dive.[8]

As the speed of capital ships increased, the United Kingdom abandoned the fleet submarine concept following completion of the three 21-knot Thames-class submarines of the early 1930s using supercharged diesels, because the size required for range and speed decreased maneuverability.[9]


Continental European nations sometimes used the terms "ocean-going", "long-patrol", "type 1" or "1st class" submarines, generally referring to Atlantic or Indian Ocean operations in the absence of anticipated need for Pacific patrols, and often without the speed for fleet operations.[10]

Comparison of World War II submarines

Name Type Nation Surface Displacement Submerged Displacement Speed Torpedo Tubes Crew Reference
Gato class fleet submarine United States 1,525 tons 2,415 tons 20 kt 10 80 [11]
Thames class fleet submarine United Kingdom 1,850 tons 2,723 tons 22 kt 8 61 [12]
Kaidai class fleet submarine Japan 1,833 tons 2,602 tons 23 kt 6 80 [13]
Type IXD2 ocean-going submarine Germany 1,616 tons 1,804 tons 19 kt 6 57 [14]
Redoutable-class ocean-going submarine France 1,570 tons 2,084 tons 17 kt 9 61 [15]
Kaichū type medium submarine Japan 1,115 tons 1,447 tons 19 kt 4 80 [16]
Type XB minelayer Germany 1,763 tons 2,177 tons 16 kt 2 52 [17]
Cagni class submarine cruiser Italy 1,461 tons 2,136 tons 18 kt 14 85 [18]
Type B1 submarine cruiser Japan 2,584 tons 3,654 tons 23 kt 6 100 [19]
O 21-class medium submarine Netherlands 888 tons 1,186 tons 19 kt 8 55 [20]
Type VIIC medium submarine Germany 769 tons 871 tons 17 kt 5 44 [21]
Pietro Micca minelayer Italy 1,371 tons 1,883 tons 15 kt 6 66 [22]
600 series medium submarine Italy 615 tons 855 tons 14 kt 6 41 [22]
S-class medium submarine United Kingdom 715 tons 990 tons 14 kt 6 44 [23]
Grampus class minelayer United Kingdom 1,520 tons 2,157 tons 15 kt 6 59 [12]
Minerve class medium submarine France 662 tons 856 tons 14 kt 9 41 [24]
Narwhal-class submarine cruiser United States 2,730 tons 4,050 tons 17 kt 6 90 [25]
Surcouf submarine cruiser France 3,250 tons 4,304 tons 18 kt 12 118 [26]
Argonaut minelayer United States 2,710 tons 4,080 tons 15 kt 4 89 [25]
S-boats medium submarine United States 840 tons 1,150 tons 15 kt 4 42 [27]


  1. ^ Friedman, pp. 99-104
  2. ^ Friedman, p. 310
  3. ^ Friedman, p. 163
  4. ^ Potter & Nimitz, p.797
  5. ^ Silverstone, p.176
  6. ^ Friedman, pp. 310-311
  7. ^ Watts, pp.161&186
  8. ^ Edward C. Whitman "K for Katastrophe" Archived 2015-09-24 at the Wayback Machine
  9. ^ Lenton & Colledge, p.135
  10. ^ le Masson, p.143
  11. ^ Silverstone, p.195
  12. ^ a b Lenton & Colledge, p.138
  13. ^ Watts, p.188
  14. ^ Taylor, p.104
  15. ^ le Masson, pp.152&153
  16. ^ Watts, p.189
  17. ^ Taylor, p.106
  18. ^ Kafka & Pepperburg, p.790
  19. ^ Watts, p.185
  20. ^ Lenton, p.43
  21. ^ Taylor, p.101
  22. ^ a b Kafka & Pepperburg, p.793
  23. ^ Lenton & Colledge, p.139
  24. ^ le Masson, p.161
  25. ^ a b Silverstone, p.186
  26. ^ le Masson, p.157
  27. ^ Silverstone, p.183


  • Alden, John D., Commander (USN Ret) (1979). The Fleet Submarine in the U.S. Navy: A Design and Construction History. London: Arms and Armour Press. ISBN 0-85368-203-8.
  • Friedman, Norman (1995). U.S. Submarines Through 1945: An Illustrated Design History. Annapolis, Maryland: United States Naval Institute. ISBN 1-55750-263-3.
  • Kafka, Roger; Pepperburg, Roy L. (1946). Warships of the World. New York: Cornell Maritime Press.
  • le Masson, Henri (1969). Navies of the Second World War. The French Navy 1. Garden City, New York: Doubleday & Company.
  • Lenton, H.T. (1968). Navies of the Second World War. Royal Netherlands Navy. Garden City, New York: Doubleday & Company.
  • Lenton, H.T.; Colledge, J.J. (1964). British and Dominion Warships of World War II. Garden City, New York: Doubleday & Company.
  • Potter, E.B.; Nimitz, Chester W. (1960). Sea Power. Englewood Cliffs, New Jersey: Prentice-Hall.
  • Silverstone, Paul H. (1968). U.S. Warships of World War II. Garden City, New York: Doubleday & Company.
  • Taylor, J.C. (1966). German Warships of World War II. Garden City, New York: Doubleday & Company.
  • Watts, Anthony J. (1966). Japanese Warships of World War II. Garden City, New York: Doubleday & Company.
AA-1-class submarine

The AA-1 class was a class of three experimental submarines of the United States Navy, built toward the end of World War I, between 1916 and 1919, intended to produce a high-speed fleet submarine. The design was not a success and none of the submarines saw active service. However, the lessons learned were applied to the design of the later V-boats. The class was later renamed as the T class.

HMS Agincourt (S125)

HMS Agincourt (also known as Astute Boat 7) is an Astute-class nuclear-powered fleet submarine under construction for the Royal Navy and the seventh in her class. The boat's name was confirmed in May 2018.The confirmation for the seventh and final Astute-class boat was given in the Strategic Defence and Security Review of October 2010, although the order was not placed until 2018.On 11 December 2012 the British government announced that long-lead items had been ordered for boats 6 and 7.On 6 March 2018 the defence procurement minister Guto Bebb confirmed that the MoD had gained Treasury approval to sign a contract for Astute Boat 7, after a leaked Navy document had suggested it might not be procured as a cost-saving measure. In May 2018 it was reported that construction of Boat Seven had begun.

HMS Ambush (S120)

HMS Ambush is an Astute-class nuclear fleet submarine of the Royal Navy, the second boat of her class. Ambush is the third vessel, and the second submarine, to bear the name in Royal Naval service. She was ordered in 1997, laid down in 2003 and commissioned in 2013.

HMS Artful (S121)

HMS Artful is the third Astute-class nuclear-powered fleet submarine of the British Royal Navy. She is the second submarine of the Royal Navy to bear this name. Artful was ordered from GEC's Marconi Marine (now BAE Systems Submarine Solutions) on 17 March 1997, and was constructed at Barrow in Furness. She was named on 20 September 2013, was rolled out of the shipyard construction hall on 16 May 2014, and was due to start sea trials in early 2015. Artful made her first successful basin dive in October 2014, and sailed on 13 August 2015 for sea trials. Artful was handed over the Royal Navy on 14 December 2015, and commissioned on 18 March 2016.

HMS Audacious (S122)

HMS Audacious is the fourth Astute-class nuclear-powered fleet submarine of the Royal Navy. Several previous vessels of the Royal Navy have borne the name. She was formally named on 16 December 2016 and was launched on 28 April 2017.

HMS Conqueror (S48)

HMS Conqueror was a British Churchill-class nuclear-powered fleet submarine which served in the Royal Navy from 1971 to 1990. She was the third submarine of her class, following the earlier Churchill and Courageous, that were all designed to face the Soviet threat at sea. She was built by Cammell Laird at Birkenhead.

Conqueror is the only nuclear-powered submarine to have engaged an enemy ship with torpedoes, sinking the cruiser General Belgrano during the 1982 Falklands War.

HMS Courageous (S50)

HMS Courageous (S50) is a decommissioned Churchill-class nuclear fleet submarine in service with the Royal Navy from 1971.

In 1982, Courageous along with her sister ship, HMS Conqueror, was sent with the British task force to retake the Falkland Islands from the occupying Argentine forces. She returned home later in the year without damage. Courageous was retired from service in 1992. She is now a museum ship at Devonport Dockyard.

During the HMNB Devonport Navy Days 2006, one of the members of the team restoring HMS Courageous pointed out that HMS Valiant was one of the first Royal Navy submarines to have her reactor removed. As Valiant had been cosmetically wrecked by this work, HMS Courageous was selected for the museum ship to represent the nuclear submarine fleet of the Royal Navy during the Cold War. Components were removed from HMS Valiant to restore Courageous. HMS Courageous was due to be moved in 2007 from her current berth to a new berth, due to development of the HMNB Devonport area where she resided.

HMS Spartan (S105)

HMS Spartan was a nuclear-powered fleet submarine of the Royal Navy's Swiftsure class. Spartan was launched on 7 April 1978 by Lady Lygo, wife of Admiral Sir Raymond Lygo. The boat was built by Vickers Limited Shipbuilding Group (now a division of BAE Systems) at Barrow-in-Furness in Cumbria, England. She was decommissioned in January 2006.

HMS Splendid (S106)

HMS Splendid was a Royal Navy nuclear-powered fleet submarine of the Swiftsure class. From her launch in 1979 she took part in many conflicts involving British forces around the globe and was decommissioned in 2004.

HMS Superb (S109)

HMS Superb was a nuclear-powered fleet submarine of the Swiftsure class serving in the Royal Navy.

She was built by Vickers Shipbuilding Group, now a division of BAE Systems Submarine Solutions. Superb was launched on 30 November 1974 at Barrow-in-Furness, Cumbria and commissioned into the Royal Navy on 13 November 1976. After being damaged in May 2008 in the Red Sea, she returned to HMNB Devonport where she was decommissioned slightly ahead of schedule on 26 September 2008.

HMS Trenchant (S91)

HMS Trenchant is a Trafalgar-class nuclear-powered fleet submarine of the Royal Navy built by Vickers Shipbuilding, Barrow-in-Furness. Trenchant is in service and is based at HMNB Devonport. She is the third vessel and the second submarine of the Royal Navy to be named for the characteristic of vigour and incisiveness.

The submarine was ordered on 22 March 1983. She was laid down by Vickers Shipbuilding on 28 October 1985, and was launched on 3 November 1986 in the presence of Vice Admiral Sir Arthur Hezlet, who had commanded the World War II T-class submarine Trenchant. She was commissioned into the Royal Navy on 14 January 1989.Trenchant is scheduled to be decommissioned in 2019.

Japanese submarine I-12

The submarine I-12 was a Japanese A2 type long-range fleet submarine. She was built at the Kawasaki's shipyard in Kobe.

Mark 10 torpedo

The Mark 10 torpedo was a torpedo put into use by the United States in 1915. It was derived from the Mark 9 aircraft torpedo converted to submarine use. It was used as the primary torpedo in the R- and S-class submarines. It used alcohol-water steam turbine propulsion. It was succeeded by the problematic Mark 14 torpedo, but remained in service in S-boats & fleet submarines through the Pacific War. The Mark 10 featured the largest warhead (497 lb (225 kg) of TNT) of any U.S. torpedo developed at that time. Stockpiles of Mark 10 Mod 3 torpedoes were used extensively during the first part of World War II due to short supply of the newer and longer (246 in (6.2 m) Mark 14s, with some fleet submarines carrying a mixture of both types on patrol.Mark 10 torpedoes, and those developed at the same time (Mark 9 air- and Mark 8 surface ship-launched) used essentially the same control package (the Ulan gear) as the newer Mark 14 for depth and direction. The running depth could be set to between 5 and 35 m (16 and 115 ft). The gyro angle could be set for a new course up to 90 degrees port or starboard from the current course of the submarine before launch. The Mark 10 would run out of the tube straight ahead for the "reach", then turn to a new, pre-set course, through a total angular targeting of 180 degrees over the end of the submarine, and then run on this intercept course straight to the target.To use a Mark 10 Mod 3 (the earlier Mark 10 torpedo mod numbers would not work) torpedo in fleet submarine tubes required a gyro angle setting spindle adapter be slipped into the torpedo housing to extend the reach of the spindle into the torpedo. In pre-fleet submarines, the gyro setting machinery was on the outside of the tube, while the fleet submarine gyro spindles are on the inside of the tube.The Mark 10 torpedo had the same "deep running" problem (where actual running depth was greater than that set before launch) as the Mark 14. By January 5, 1942 the Bureau of Ordnance informed Commander, Submarines, Pacific Fleet the Mark 10 torpedoes ran four feet deeper than set. Because the Mark 10 used Mark 3-1 and Mark 3-3 exploder mechanism with contact-only firing, it suffered none of the problems with prematures or duds the Mark 14 did. However, for a short period at the beginning of the war, the Mark 10 was viewed as more reliable, and in some cases preferred over the Mark 14.

Portsmouth Naval Shipyard

The Portsmouth Naval Shipyard (PNS), often called the Portsmouth Navy Yard, is a United States Navy shipyard located in Kittery on the southern boundary of Maine near the city of Portsmouth, New Hampshire. PNS is tasked with the overhaul, repair, and modernization of US Navy submarines. The facility is sometimes confused with the Norfolk Naval Shipyard in Portsmouth, Virginia.

Salmon-class submarine

The United States Navy Salmon-class submarines were an important developmental step in the design of the "fleet submarine" concept during the 1930s. An incremental improvement over the previous Porpoise class, they were the first US submarine class to achieve 21 knots with a reliable propulsion plant, allowing them to operate with the Standard-type battleships of the surface fleet. Also, their 11,000 nautical miles (20,000 km) unrefueled range would allow them to operate in Japanese home waters. These rugged and dependable boats provided yeoman service during World War II, along with their immediate successors, the similar Sargo class. In some references, the Salmons and Sargos are called the "New S Class", 1st and 2nd Groups.

Sargo-class submarine

The Sargo-class submarines were among the first US submarines to be sent into action after the Japanese attack on Pearl Harbor, starting war patrols the day after the attack, having been deployed to the Philippines in late 1941. Similar to the previous Salmon class, they were built between 1937 and 1939. With a top speed of 21 knots, a range of 11,000 nautical miles (20,000 km) (allowing patrols in Japanese home waters), and a reliable propulsion plant, along with the Salmons they were an important step in the development of a true fleet submarine. In some references, the Salmons and Sargos are called the "New S Class", 1st and 2nd Groups.The Sargo-class submarine USS Swordfish (SS-193) had the distinction of being the first US Navy submarine to sink a Japanese ship in World War II.

Tambor-class submarine

The Tambor-class submarine was a United States Navy submarine design, used primarily during World War II. It was the USN's first fully successful fleet submarine, and began the war close to the fighting. Six of the class were in Hawaiian waters or the Central Pacific on 7 December 1941, with Tautog at Pearl Harbor during the attack. They went on to see hard service; seven of the twelve boats in the class were sunk before the survivors were withdrawn from front-line service in early 1945; this was the highest percentage lost of any US submarine class. Tautog was credited with sinking 26 ships, the largest number of ships sunk by a US submarine in World War II. The Tambors retained the top speed of 21 knots (39 km/h) and range of 11,000 nautical miles (20,000 km) (allowing patrols in Japanese home waters) of the preceding Sargo class, and improvements included six bow torpedo tubes, a more reliable full diesel-electric propulsion plant, and improved combat efficiency with key personnel and equipment relocated to the conning tower. In some references, the Tambors are called the "T Class", and SS-206 through SS-211 are sometimes called the "Gar class".

USS Barracuda (SS-163)

USS Barracuda (SF-4/SS-163), lead ship of her class and first of the "V-boats," was the second ship of the United States Navy to be named for the barracuda (after USS F-2). Her keel was laid down at Portsmouth Navy Yard. She was launched as V-1 (SF-4) on 17 July 1924, sponsored by Mrs. Cornelia Wolcott Snyder, wife of Captain Snyder, and commissioned on 1 October 1924 with Lieutenant Commander S. Picking in command. V-1 and her sisters V-2 (Bass) and V-3 (Bonita) were the only class of the nine "V-boats" designed to meet the fleet submarine requirement of 21 knots (39 km/h) surface speed for operating with contemporary battleships.

Valiant-class submarine

The Valiant class were a class of nuclear-powered fleet submarines in service with the Royal Navy from the mid-1960s until 1994. They were the first fully British nuclear fleet submarine; the earlier HMS Dreadnought used an American nuclear reactor. There were only two boats in the class, the first, Valiant (the nameship) commissioned in 1966 three years after Dreadnought, and Warspite the following year. Both were built by Vickers at Barrow-in-Furness.

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