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". [1] They are also used to protect friendly surface combatants and missile submarines. [2] 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 United States 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 US Navy, SSNs are unofficially called "fast attacks". [3]
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. [4] [5]
In the action of 9 February 1945, HMS Venturer sank U-864 while both were at periscope depth. This was the first and so far only intentional sinking of a submerged submarine by a submerged submarine. U-864 was snorkeling, thus producing much noise for Venturer'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. Venturer'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. [6] [7]
Following World War II, advanced German submarines, especially the Type XXI U-boat, became available to the Allies, particularly the United States 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. [8] In the US Navy, the Greater Underwater Propulsion Power Program (GUPPY) was developed to modernize World War II submarines along the lines of the Type XXI. [9] By 1955 the U.S. Navy was using the term 'attack submarine' to describe the GUPPY conversions and the first postwar submarines (the Tang class and the Darter). [10]
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 US 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 US 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 US submarine force at the end of World War II, excluding obsolescent training submarines, was just over 200 boats. [8]
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 750 long tons (760 t ) surfaced, they were considerably smaller than the 1,650 long tons (1,680 t ) 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 Gato class was chosen for this, as some of the deeper-diving Balao- and Tench-class 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. [8] [11]
The Soviets took longer than anticipated to start producing new submarines in quantity. By 1952 only ten had entered service. [12] 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. [13] [14]
USS Nautilus, 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. [15]
As the development and deployment of nuclear submarines proceeded, in 1957–59 the US 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.
Research proceeded rapidly to maximize the potential of the nuclear submarine for the ASW and other missions. The US Navy developed a fully streamlined hull form and tested other technologies with the conventional USS Albacore, commissioned in 1953. The new hull form was first operationalized with the three conventional Barbel-class boats and the six nuclear Skipjack-class boats, when both classes entered service beginning in 1959. [16] [17] The Skipjack 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. [18] The one-off Tullibee in 1960 and the Thresher class starting in 1961 were the first with a bow-mounted sonar sphere; midships torpedo tubes angled outboard were fitted to make room for the sphere. [8] [19]
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. [20] 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. [21]
Thresher's loss in April 1963 triggered a major redesign of subsequent US submarines known as the SUBSAFE program. [17] However, Thresher's general arrangement and concept were continued in all subsequent US Navy attack submarines.
Britain commissioned its first nuclear attack submarine HMS Dreadnought in 1963 with a US S5W reactor. At the same time as the Dreadnought construction, attempts were made to transfer US 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 Lenin reportedly "appalled him" and convinced him that he should cancel the transfers to retain secrets. [22] [23]
The first fully streamlined Soviet attack submarines were the Project 671 "Yorsh" class (NATO Victor I class), which first entered service in 1967. [13] [24]
China commissioned its first nuclear attack submarine Changzheng 1 (NATO Han class) in 1974, and France its first Rubis-class submarine in 1983. [25] [26]
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 HMS Conqueror torpedoed and sank the Argentine light cruiser ARA General Belgrano. [27]
The United States commissioned the Seawolf and Virginia-class nuclear powered submarines in 1997 and 2004 respectively.
As of 2021 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. [28] [29] [30] [31]
Conventional attack submarines have however remained relevant throughout the nuclear era, with the British Oberon class and the Soviet Romeo, Foxtrot, Tango and Kilo 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, Scorpène and Gotland classes of submarine. The US Navy leased HSwMS Gotland to perform the opposing force role during ASW exercises tactics. [32] The Gotland caused a stir in 2005 when during training it "sank" the American carrier USS Ronald Reagan. [33] [34]
The Sturgeon class was a class of nuclear-powered fast attack submarines (SSN) in service with the United States Navy from the 1960s until 2004. They were the "workhorses" of the Navy's attack submarine fleet throughout much of the Cold War. The boats were phased out in the 1990s and early 21st century, as their successors, the Los Angeles, followed by the Seawolf and Virginia-class boats, entered service.
The Gato class of submarines were built for the United States Navy and launched in 1941–1943. Named after the lead ship of the class, USS Gato, they were the first mass-production U.S. submarine class of World War II.
USS Barracuda (SSK-1/SST-3/SS-550), the lead ship of her class, was a submarine that was the third ship of the United States Navy to be named for the barracuda, a voracious, pike-like fish. Her keel was laid down on 1 July 1949 by the Electric Boat Division of General Dynamics Corporation in Groton, Connecticut. She was launched on 2 March 1951 as K-1, sponsored by Mrs. Willis Manning Thomas, and commissioned on 10 November 1951. Notably, future President of the United States Jimmy Carter served as an officer on K-1 as part of its pre-commissioning crew and during its first year of active service until he was reassigned on 16 October 1952.
A cruise missile submarine is a submarine that carries and launches cruise missiles as its primary armament. Missiles greatly enhance a warship's ability to attack surface combatants and strike land targets; although torpedoes are a more discreet option for submerged submarines, missiles give a much longer stand-off range, shorter time to impact the target, as well as the ability to engage multiple targets on different headings at the same time. Many cruise missile submarines retain the capability to deploy nuclear warheads on their missiles, but they are considered distinct from ballistic missile submarines due to the substantial differences between the two weapons systems' flight characteristics; cruise missiles fly aerodynamically using flight surfaces like wings or fins, while a ballistic missile uses its engine power alone as it may exit the atmosphere.
USS Tullibee (SSN-597), a unique submarine, was the second ship of the United States Navy to be named for the tullibee, any of several whitefishes of central and northern North America.
USS Bonita (SSK-3/SS-552), a Barracuda-class submarine, was the fourth ship of the United States Navy to be named for the bonito, a name applied to several types of fish, including the skipjack tuna,, the Atlantic bonito, the lesser amberjack, or the cobia. She was originally named USS K-3 (SSK-3).
USS Bass (SSK-2/SS-551), a Barracuda-class submarine, was the second ship of the United States Navy to be named for the bass, an edible, spiny-finned fish. She was originally named USS K-2 (SSK-2).
The Permit-class submarine was a class of nuclear-powered fast attack submarines in service with the United States Navy from the early 1960s until 1996. They were a significant improvement on the Skipjack class, with greatly improved sonar, diving depth, and silencing. They were the forerunners of all subsequent US Navy SSN designs. They served from the 1960s through to the early 1990s, when they were decommissioned due to age. They were followed by the Sturgeon and Los Angeles classes.
The Skipjack class was a class of United States Navy nuclear submarines (SSNs) that entered service from 1959 to 1961. This class was named after its lead boat, USS Skipjack. The new class introduced the teardrop hull and the S5W reactor to U.S. nuclear submarines. The Skipjacks were the fastest U.S. nuclear submarines until the Los Angeles-class submarines, the first of which entered service in 1974.
The Tang-class submarines were the first submarines designed and built by the United States Navy after World War II. They incorporated the best features of the high-speed German Type XXI U-boat and the venerable U.S. Navy fleet submarine. The Tang class, with the fleet submarines converted under the Greater Underwater Propulsion Power (GUPPY) program, had much higher submerged performance than their predecessors, but were quickly surpassed by the nuclear-propelled submarines that entered service beginning in 1954. Six units in total were built.
The Skate-class submarines were the United States Navy's first production run of nuclear-powered submarines. They were an evolution of the Tang class in everything except their propulsion plants, which were based on the operational prototype USS Nautilus. The four Skate class boats re-introduced stern torpedo tubes. Although among the smallest nuclear-powered attack submarines ever built, the Skate class served for many years, with the last being decommissioned in 1989. USS Skate was the first submarine to surface at the North Pole, on 17 March 1959.
The Barracuda-class submarines were the product of Project Kayo, a research and development effort begun immediately after World War II by the United States Navy to "solve the problem of using submarines to attack and destroy enemy submarines". They originally had the hull classification symbol SSK, for "hunter-killer submarine".
The Kilo-class submarines are a group of diesel-electric attack submarines designed by the Rubin Design Bureau in the Soviet Union in the 1970s and built originally for the Soviet Navy.
Air-independent propulsion (AIP), or air-independent power, is any marine propulsion technology that allows a non-nuclear submarine to operate without access to atmospheric oxygen. AIP can augment or replace the diesel-electric propulsion system of non-nuclear vessels.
The Gotland-class submarines of the Swedish Navy are modern diesel-electric submarines, which were designed and built by the Kockums shipyard in Sweden. They are the first submarines in the world to feature a Stirling engine air-independent propulsion (AIP) system, which extends their underwater endurance from a few days to weeks. This capability had previously only been available with nuclear-powered submarines.
Anti-submarine warfare is a branch of underwater warfare that uses surface warships, aircraft, submarines, or other platforms, to find, track, and deter, damage, or destroy enemy submarines. Such operations are typically carried out to protect friendly shipping and coastal facilities from submarine attacks and to overcome blockades.
The People's Liberation Army Navy Submarine Force (PLANSF) is the submarine service of the People's Liberation Army Navy. It consists of all types of submarines in operational service organized into three fleets: the North Sea Fleet, the East Sea Fleet, and the South Sea Fleet. Submarines have long been one of the three focuses of the People's Liberation Army Navy, and when the decision was made in late 2006 to concentrate on building other principal surface combatants to strengthen the air defense and to further delay the construction of aircraft carriers due to insufficient air cover, submarines will continue to play the lead dominant role in the assault force for the PLAN. Currently, PLANSF operates a fleet of 66 submarines which include nuclear as well as conventional submarines.
SSK was the United States Navy hull classification symbol for a diesel-electric submarine specialized for anti-submarine duties. SS indicated that the vessel was a submarine, and the K suffix that it was a hunter-killer. The United States Navy does not currently operate any submarines of this type, and so the designation is inactive.
Project Nobska was a 1956 summer study on anti-submarine warfare (ASW) for the United States Navy ordered by Chief of Naval Operations Admiral Arleigh Burke. It is also referred to as the Nobska Study, named for its location on Nobska Point near the Woods Hole Oceanographic Institution (WHOI) on Cape Cod, Massachusetts. The focus was on the ASW implications of nuclear submarines, particularly on new technologies to defend against them. The study was coordinated by the Committee on Undersea Warfare (CUW) of the National Academy of Sciences (NAS). It was notable for including 73 representatives from numerous organizations involved in submarine design, submarine-related fields, and weapons design, including senior scientists from the Atomic Energy Commission's nuclear weapons laboratories. Among the participants were Nobel laureate Isidor Rabi, Paul Nitze, and Edward Teller. The study's recommendations influenced all subsequent US Navy submarine designs, as well as submarine-launched ASW tactical nuclear weapons until this weapon type was phased out in the late 1980s. New lightweight and heavyweight anti-submarine torpedo programs were approved. Although not on the initial agenda, the Polaris submarine-launched ballistic missile (SLBM) was determined to be capable of implementation at this conference. Within five years Polaris would dramatically improve the US Navy's strategic nuclear deterrent capability.