Origins During
World War II, submarines that fulfilled the offensive surface attack role were termed
fleet submarines in the U.S. Navy and "ocean-going", "long-patrol", "type 1" or "1st class" by continental European navies. In the
action of 9 February 1945, sank while both were at
periscope depth. This was the first and so far only intentional sinking of a submerged submarine by another submerged submarine.
U-864 was snorkeling, thus producing much noise for
Venturers
hydrophones (an early form of passive
sonar) to detect, and
Venturer was fortunate in having over 45 minutes to plot the
U-boat's zig-zag course by observing the snorkel mast.
Venturers commander,
James S. "Jimmy" Launders, was astute in assuming the U-boat would execute an "
emergency deep" maneuver once it heard the torpedoes in the water, thus the "spread" of four torpedoes immediately available was aimed on that assumption. One hit, sinking the U-boat.
Beginnings of the attack submarine type Following World War II, advanced German submarines, especially the
Type XXI U-boat, became available to the Allies, particularly the U.S. Navy and the Soviet Navy. Initially, the
Type XVII U-boat, with a Walter
hydrogen peroxide-fueled
gas turbine allowing high sustained underwater speed, was thought to be more developed than was actually the case, and was viewed as the submarine technology of the immediate future. However, the Type XXI, streamlined and with a high battery capacity for high submerged speed, was fully developed and became the basis for most non-nuclear submarine designs worldwide through the 1950s. In the U.S. Navy, the
Greater Underwater Propulsion Power Program (GUPPY) was developed to modernize World War II submarines along the lines of the Type XXI. By 1955 the U.S. Navy was using the term 'attack submarine' to describe the GUPPY conversions and the first postwar submarines (the and the ).
Beginnings of a separate hunter-killer submarine type (SSK) It was realized that the
Soviet Union had acquired Type XXI and other advanced U-boats and would soon be putting their own equivalents into production. In 1948 the U.S. Navy prepared estimates of the number of
anti-submarine warfare (ASW)-capable submarines that would be needed to counter the hundreds of advanced Soviet submarines that were expected to be in service by 1960. Two scenarios were considered: a reasonable scenario assuming the Soviets would build to their existing force level of about 360 submarines, and a "nightmare" scenario projecting that the Soviets could build submarines as fast as the Germans had built U-boats, with a force level of 2,000 submarines. The projected U.S.
SSK force levels for these scenarios were 250 for the former and 970 for the latter. Additional anti-surface (i.e., 'attack'),
guided missile, and
radar picket submarines would also be needed. By comparison, the total U.S. submarine force at the end of World War II, excluding obsolescent training submarines, was just over 200 boats. with BQR-4 sonar dome A small submarine suitable for mass production was designed to meet the SSK requirement. This resulted in the three submarines of the
K-1 class (later named the
Barracuda class), which entered service in 1951. At surfaced, they were considerably smaller than the boats produced in World War II. They were equipped with an advanced passive sonar, the bow-mounted BQR-4, but had only four
torpedo tubes. Initially, a sonar located around the conning tower was considered, but tests showed that bow-mounted sonar was much less affected by the submarine's own noise. While developing the purpose-built SSKs, consideration was given to converting World War II submarines into SSKs. The less-capable was chosen for this, as some of the deeper-diving - and boats were being upgraded as GUPPYs.
Seven Gato-class boats were converted to SSKs in 1951–53. These had the bow-mounted BQR-4 sonar of the other SSKs, with four of the six bow torpedo tubes removed to make room for the sonar and its electronics. The four stern torpedo tubes were retained. Two diesel engines were removed, and the auxiliary machinery was relocated in their place and sound-isolated to reduce the submarine's own noise. The Soviets took longer than anticipated to start producing new submarines in quantity. By 1952 only ten had entered service. However, production was soon ramped up. By the end of 1960 a total of 320 new Soviet submarines had been built (very close to the USN's 1948 low-end assumption), 215 of them were the
Project 613 class (NATO Whiskey class), a smaller derivative of the Type XXI. Significantly, eight of the new submarines were nuclear-powered.
Nuclear era End of the U.S. conventional hunter-killers (SSK) , the world's first
nuclear submarine, was operational in 1955; the Soviets followed this only three years later with their first
Project 627 "Kit"-class SSN (NATO November class). Since a nuclear submarine could maintain a high speed at a deep depth indefinitely, conventional SSKs would be useless against them: As the development and deployment of nuclear submarines proceeded, in 1957–59 the U.S. Navy's SSKs were decommissioned or redesignated and reassigned to other duties. It had become apparent that all nuclear submarines would have to perform ASW missions.
Other new technologies Research proceeded rapidly to maximize the potential of the nuclear submarine for the ASW and other missions. The U.S. Navy developed a fully streamlined hull form and tested other technologies with the conventional , commissioned in 1953. The new hull form was first operationalized with the three conventional boats and the six nuclear boats, when both classes entered service beginning in 1959. Both classes used the BQS-4 and BQR-2 bow mounted sonars. The was declared the "world's fastest submarine" following trials, although the actual speed was kept secret. Sonar research showed that a sonar sphere capable of three-dimensional operation, mounted at the very bow of a streamlined submarine, would increase detection performance. This was recommended by
Project Nobska, a 1956 study ordered by
Chief of Naval Operations Admiral
Arleigh Burke. The one-off in 1960 and the starting in 1961 were the first with a bow-mounted sonar sphere, the BQQ-2; midships torpedo tubes angled outboard were fitted to make room for the sphere.
Failure to develop a U.S. nuclear hunter-killer (SSKN) Tullibee was a type of nuclear-powered SSK; technologically very successful, intentionally slow but ultra-quiet with
turbo–electric drive. Her unexpectedly high cost compared with the
Thresher proved it was impossible to build a low-cost nuclear SSK (several
nuclear reactor features could not be scaled down beyond a certain point, including
radiation shielding). This result coupled with her lower performance was judged to be not
cost-effective and the type was not repeated; the Navy decided to merge the hunter-killer role with the attack submarines, making the terms interchangeable.
Thresher was faster and had an increased diving depth, carried twice as many torpedoes, included comparable sound silencing improvements, and was commissioned only nine months later.
Thresher's loss in April 1963 triggered a major redesign of subsequent U.S. submarines known as the
SUBSAFE program. However,
Threshers general arrangement and concept were continued in all subsequent U.S. Navy attack submarines.
Later developments Britain commissioned its first nuclear attack submarine in 1963 with a U.S.
S5W reactor. At the same time as the
Dreadnought construction, attempts were made to transfer U.S. naval reactor technology to Canada and the Netherlands. Admiral
Hyman G. Rickover considered such technology to be obvious, but a visit to the Soviet nuclear icebreaker reportedly "appalled him" and convinced him that he should cancel the transfers to retain secrets. The first fully streamlined Soviet attack submarines were the
Project 671 "Yorsh" class (NATO Victor I class), which first entered service in 1967. Only twice has a nuclear attack submarine engaged and sank an enemy warship. The first was in the
Falklands War, when on 2 May 1982 the
British nuclear submarine torpedoed and sank the
Argentine light cruiser . The second was on 4 March 2026 when the USN
Los Angeles Class Submarine USS Charlotte sank the Iranian Frigate
IRIS Dena off the South-West coast of Sri Lanka during the
2026 Iran War. The U.S. Navy commissioned the first
Seawolf and
Virginia-class nuclear powered submarines in 1997 and 2004 respectively. As of 2026 Brazil has a nuclear attack submarine
under construction, India has
finalized a nuclear attack submarine interim design, and Australia has started a nuclear attack submarine program under the
AUKUS security pact with UK and US assistance.
Modern conventional submarines module of the
Kalvari class submarines Conventional attack submarines have however remained relevant throughout the nuclear era, with the British class and the Soviet , , and classes being good examples which served during the
Cold War. With the advent of
air-independent propulsion technology, these submarines have grown more and more capable. Examples include the
Type 212, and classes of submarine. The U.S. Navy
leased to perform the opposing force role during
ASW exercises tactics. The
Gotland caused a stir in 2005 when during training it "sank" the American carrier . ==Operators==