Attack submarine

File:HMCS Windsor SSK 877.jpg

HMCS Windsor, an attack submarine of the Royal Canadian Navy

An attack submarine or hunter-killer submarine is a submarine specifically designed for the purpose of attacking and sinking other submarines, surface combatants, and merchant vessels. In the Soviet and Russian navies they were and are called "multi-purpose submarines".Template:Sfnp They are also used to protect friendly surface combatants and missile submarines. Some attack subs are also armed with cruise missiles, increasing the scope of their potential missions to include land targets.

Attack submarines may be either nuclear-powered or diesel–electric ("conventionally") powered. In the U.S. Navy naming system, and in the equivalent NATO system (STANAG 1166), nuclear-powered attack submarines are known as SSNs and their anti-submarine (ASW) diesel–electric predecessors are SSKs. In the U.S. Navy, SSNs are unofficially called "fast attacks".

History

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.Template:SfnpTemplate:Sfn

In the action of 9 February 1945, sank Template:GS 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 VenturerTemplate:'s 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. VenturerTemplate:'s 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.Template:SfnTemplate:Sfn

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.Template:Sfnp 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 ).Template:Sfnp

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.Template:Sfnp

File:USS Bonita (SSK-3).jpg

USS K-3 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.Template:Sfnp

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.Template:Sfnp

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:

By the fall of 1957, Nautilus had been exposed to 5,000 dummy attacks in U.S. exercises. A conservative estimate would have had a conventional submarine killed 300 times: Nautilus was ruled as killed only 3 times...Using their active sonars, nuclear submarines could hold contact on diesel craft without risking counterattack...In effect, Nautilus wiped out the ASW progress of the past decade.Template:Sfnp

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

File:USS Thresher underway April 1961.jpg

, the first high-speed deep-diving SSN optimized for both ASW and surface attack

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.Template:SfnpTemplate:Sfnp 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.Template:Sfnp 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.Template:Sfnp

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.Template:Sfnp 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.Template:Sfnp

Thresher's loss in April 1963 triggered a major redesign of subsequent U.S. submarines known as the SUBSAFE program.Template:Sfnp However, ThresherTemplate:'s 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. 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.Template:SfnpTemplate:Sfnp

The first fully streamlined Soviet attack submarines were the Project 671 "Yorsh" class (NATO Victor I class), which first entered service in 1967.Template:Sfnp

China commissioned its first nuclear attack submarine (NATO Han class) in 1974, and France its first in 1983.

The only time in history that a nuclear attack submarine engaged and sank an enemy warship was in the Falklands War, when on 2 May 1982 the British nuclear submarine torpedoed and sank the Argentine light cruiser .Template:Sfnp

The U.S. Navy commissioned the first Seawolf and Virginia-class nuclear powered submarines in 1997 and 2004 respectively.

As of 2025 Brazil has a nuclear attack submarine under construction, India has finalized a nuclear attack submarine interim design,Template:SfnTemplate:Sfn and Australia has started a nuclear attack submarine program under the AUKUS security pact with UK and US assistance.

Modern conventional submarines

File:HMS Gotland with USS Ronald Reagan.jpg

Template:HSwMS with

File:DRDO AIP (Air Independent Propulsion) model for Kalvari-class submarine.jpg

The Air-independent propulsion 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 Template:HSwMS 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 .Template:Sfn

Operators

Current operators

• Template:Navy/core operates six s.
• Template:Navy/core operates one Type 209 submarine as a pier-side trainer; one remains in inventory but is inactive.
• Template:Navy/core operates six s.
• Template:Navy/core operates two Ming-class submarines.
• Template:Navy/core operates five Type 209 submarines and three s.
• Template:Navy/core operates four s.
• Template:Navy/core operates two Type 209 submarines and two s.
• Template:Navy/core operates six Shang-class submarines, three Han-class submarines, seventeen Yuan-class submarines, thirteen Song-class submarines, twelve s, and four Ming-class submarines.
• Template:Navy/core operates two s, one and one .
• Template:Navy/core operates two Type 209 submarines and two Type 206 submarines.
• Template:Navy/core operates two Type 209 submarines.
• Template:Navy/core operates four Type 209 submarines and four s.
• Template:Navy/core operates two s and three s.
• Template:Navy/core operates six Type 212 submarines.
• Template:Navy/core operates six Type 209 submarines and four Type 214 submarines.
• Template:Navy/core operates four Type 209 submarines, six s, and seven s.
• Template:Navy/core operates three s and one .
• Template:Navy/core operates three s.
• Template:Navy/core operates five s, with a sixth on sea trials as of late 2024.
• Template:Navy/core operates four s and four Type 212 submarines.
• Template:Navy/core operates nine s, twelve s, and three s.Template:Sfn
• Template:Navy/core operates twenty s.
• Template:Navy/core operates nine s, nine Type 214 submarines, and two KSS-III submarines.
• Template:Navy/core operates two s.
• Template:Navy/core operates a single , gifted by India,Template:Sfn and a single Ming-class submarine, purchased from China.
• Template:Navy/core operates three s.
• Template:Navy/core operates six s.
• Template:Navy/core operates five s.
• Template:Navy/core operates six Type 209 submarines.
• Template:Navy/core operates one .
• Template:Navy/core operates two Type 214 submarines.
• Template:Navy/core possesses a single , though it is not operational.
• Template:Navy/core operates ten s, two s, two s, and c. twenty-one s (of which nine are the "Improved Kilo" variant).
• Template:Navy/core operates two s and two s, all purchased from Sweden.
• Template:Navy/core operates three Type 209 submarines.
• Template:Navy/core operates one and one as of late 2024.
• Template:Navy/core operates three s and one .
• Template:Navy/core operates twelve Type 209 submarines.
• Template:Navy/core operates five s as of late 2024.
• Template:Naval operates twenty-three s, three s, and twenty-four s.
• Template:Navy/core operates two Type 209 submarines.
• Template:Navy/core operates six s.

Former operators

• Template:Navy/core retired all four of its s in 1989.
• Template:Navy/core decommissioned its last , Slava in 2011.
• Template:Navy/core retired all three of its s in the 1990s.
• Template:Navy/core retired its last two s and its lone in 2005.
• Template:Navy/core retired its six s from active service in 1984.
• Template:Navy/core decommissioned its last in 2006.
• Template:Navy/core transferred its entire navy to Montenegro upon their independence in 2006.
• Template:Navy/core retired all three of its s in 1993.
• Template:Navy/core only submarine, , was captured by the Russian Navy during the 2014 Annexation of Crimea.

Former operators (pre-modern attack)

• Template:Navy/core lost its entire fleet following the Empire's collapse after World War I.
• Template:Navy/core two s were seized by the Soviet Union in 1940. After Estonia regained independence in 1991, it took back , and was kept in ceremonial commission as the flagship until 2011.
• Template:Navy/core forced to decommission all five of its submarines following World War II under the Paris Peace Treaty.
• Template:Navy/core two s were seized by the Soviet Union in 1940.
• Template:Navy/core decommissioned its last in 1951.

See also

• List of submarine classes in service
• List of submarine operators
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References

Sources

• Public Domain This article incorporates text from the public domain Dictionary of American Naval Fighting Ships.

External links

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