35-590: Submarine warfare is one of the four divisions of underwater warfare , the others being anti-submarine warfare , mine warfare and mine countermeasures . Submarine warfare consists primarily of diesel and nuclear submarines using torpedoes , missiles or nuclear weapons , as well as advanced sensing equipment, to attack other submarines, ships, or land targets. Submarines may also be used for reconnaissance and landing of special forces as well as deterrence. In some navies they may be used for task force screening. The effectiveness of submarine warfare partly depends on
70-622: A meridian travels approximately one minute of geographic latitude in one hour. The length of the internationally agreed nautical mile is 1 852 m . The US adopted the international definition in 1954, having previously used the US nautical mile ( 1 853 .248 m ). The UK adopted the international nautical mile definition in 1970, having previously used the UK Admiralty nautical mile ( 6 080 ft or 1 853 .184 m ). (* = approximate values) The speeds of vessels relative to
105-563: A cruiser, and several other ships. However, following a doctrine that concentrated on attacking warships, rather than more-vulnerable merchantmen, the smaller Japanese fleet proved ineffectual in the long term, while suffering heavy losses to Allied anti-submarine measures. Italian submarines and one German submarine operated in the Pacific Ocean, but never enough to be an important factor, inhibited by distance and difficult relations with their Japanese ally. Japanese submarines operated in
140-452: A distance in nautical miles on a chart can easily be measured by using dividers and the latitude scales on the sides of the chart. Recent British Admiralty charts have a latitude scale down the middle to make this even easier. Speed is sometimes incorrectly expressed as "knots per hour", which would mean "nautical miles per hour per hour" and thus would refer to acceleration . Prior to 1969, airworthiness standards for civil aircraft in
175-511: A significant part in underwater warfare. Seabed warfare is defined as "operations to, from and across the ocean floor." In general the target of seabed warfare is infrastructure in place on the seabed such as power cables, telecom cables, or natural resource extraction systems. Knot (unit) The knot ( / n ɒ t / ) is a unit of speed equal to one nautical mile per hour, exactly 1.852 km/h (approximately 1.151 mph or 0.514 m/s ). The ISO standard symbol for
210-472: A standard nautical chart using Mercator projection , the horizontal (East–West) scale varies with latitude. On a chart of the North Atlantic, the scale varies by a factor of two from Florida to Greenland. A single graphic scale , of the sort on many maps, would therefore be useless on such a chart. Since the length of a nautical mile, for practical purposes, is equivalent to about a minute of latitude,
245-500: Is 14.40 {\displaystyle 14.40} metres per knot. Although the unit knot does not fit within the SI system, its retention for nautical and aviation use is important because the length of a nautical mile , upon which the knot is based, is closely related to the longitude / latitude geographic coordinate system . As a result, nautical miles and knots are convenient units to use when navigating an aircraft or ship. On
280-463: Is a multi-role platform. It can conduct both overt and covert operations. In peacetime it can act as a deterrent as well as for surveillance operations and information gathering. In wartime a submarine can carry out a number of missions including: Underwater warfare Underwater warfare , also known as undersea warfare or subsurface warfare , is naval warfare involving underwater vehicle or combat operations conducted underwater . It
315-564: Is one of the four operational areas of naval warfare , the others being surface warfare , aerial warfare , and information warfare . Underwater warfare includes: In the 20th century underwater warfare was dominated by the submarine. They first came to prevalence during the First World War , when German U-boats attacked and sank many allied vessels, such as the sinking of the Lusitania in 1915. A similar scenario occurred during
350-533: The International Civil Aviation Organization list the knot as permitted for temporary use in aviation, but no end date to the temporary period has been agreed as of 2024 . Until the mid-19th century, vessel speed at sea was measured using a chip log . This consisted of a wooden panel, attached by line to a reel, and weighted on one edge to float perpendicularly to the water surface and thus present substantial resistance to
385-589: The Second World War , when German U-boats launched a prolonged campaign against Allied shipping, especially in the mid-Atlantic. Japanese submarines also played a minimal role on the Pacific front , and American submarines sank a total of 5.3 million tons of Axis shipping throughout the war, most of which was scored against the Japanese. In the 21st century unmanned underwater vehicles are coming to play
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#1732780988127420-563: The Treaty of Brest-Litovsk . During the war, the British invested efforts into developing a submarine that could operate in conjunction with a battleship fleet – the "Fleet Submarine". To achieve the necessary 20 knots (37 km/h) (surfaced) the K-class submarines were steam powered. In practice, the K class were a constant problem and could not operate effectively with a fleet. Between
455-715: The United States and Confederate States Navies . Submarine watercraft were among the newly created vessels. The first sinking of an enemy ship by a submarine occurred on 17 February 1864 , when the Confederate submarine H. L. Hunley , a privateer , sank the sloop USS Housatonic in Charleston Harbor , South Carolina . Shortly afterward, however, H. L. Hunley sank, with the loss of her entire crew of eight. Submarine warfare in World War I
490-552: The anti-submarine warfare carried out in response. The first attack by a submarine occurred on September 8, 1776, by the American submarine Turtle in an unsuccessful attack on the British warship Eagle. The age of submarine warfare began during the American Civil War . The 1860s was a time of many turning points in terms of how naval warfare was fought. Many new types of warships were being developed for use in
525-430: The fluids in which they travel (boat speeds and air speeds ) can be measured in knots. If so, for consistency, the speeds of navigational fluids ( ocean currents , tidal streams , river currents and wind speeds ) are also measured in knots. Thus, speed over the ground (SOG; ground speed (GS) in aircraft) and rate of progress towards a distant point (" velocity made good ", VMG) can also be given in knots. Since 1979,
560-541: The sailing master 's dead reckoning and navigation . This method gives a value for the knot of 20 + 1 ⁄ 4 inches per second or 1.85166 kilometres per hour. The difference from the modern definition is less than 0.02%. Derivation of knots spacing: 1 kn = 1852 m/h = 0.5144 m/s {\displaystyle 1~{\textrm {kn}}=1852~{\textrm {m/h}}=0.5144~{\textrm {m/s}}} , so in 28 {\displaystyle 28} seconds that
595-557: The sinking of Lusitania , turned American public opinion against the Central Powers. The U.S. demanded it stop, and Germany conducted submarine attacks under prize rules from September 1915 to January 1917. Admiral Henning von Holtzendorff (1853–1919), chief of the admiralty staff, argued successfully in December 1916 to resume unrestricted attacks from February 1917 and thus starve the British. The German high command realized
630-528: The Atlantic, where German submarines again sought out and attacked Allied convoys, this part of the war was very reminiscent of the latter part of World War I. Many British submarines were active as well, particularly in the Mediterranean and off Norway, against Axis warships, submarines and merchant shipping. Initially, Hitler ordered his submarines to abide by the prize rules, but this restriction
665-798: The Indian Ocean, forcing the British surface fleet to withdraw to the east coast of Africa. Some German and Italian submarines operated in the Indian Ocean, but never enough to play a significant role. Since the Second World War, several wars, such as the Korean War , Indo-Pakistani War of 1971 and the Falklands War , have involved limited use of submarines. Later submarine-launched land-attack missiles were employed against Iraq and Afghanistan. With these exceptions, submarine warfare ceased after 1945. Hence strategic thinking about
700-668: The UK accepted German parity in submarine numbers with the Royal Navy . In World War II, submarine warfare was split into two main areas – the Atlantic and the Pacific. The Mediterranean Sea was also a very active area for submarine operations. This was particularly true for the British and French, as well as the Germans. The Italians were also involved, but achieved their greatest successes using midget submarines and human torpedoes . In
735-668: The United States Federal Aviation Regulations specified that distances were to be in statute miles, and speeds in miles per hour. In 1969, these standards were progressively amended to specify that distances were to be in nautical miles, and speeds in knots. The following abbreviations are used to distinguish between various measurements of airspeed : The indicated airspeed is close to the true airspeed only at sea level in standard conditions and at low speeds. At 11 000 m ( 36 000 ft), an indicated airspeed of 300 kn may correspond to
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#1732780988127770-594: The ability to use torpedoes against ships, other submarines, and land targets. In response to this the attack submarine became more important, particularly in regard to its postulated role as a hunter-killer. The US also used nuclear submarines as radar pickets for a while. There have also been major advances in sensors and weapons. During the Cold War, the United States and the Soviet Union played what
805-466: The already capable Type 209 ( Chang Bogo class ) design from Germany and sold copies to Indonesia. Russia has improved the old Soviet Kilo model into what strategic analysts are calling equivalent to the 1980s-era Los Angeles class , and so on. At the end of his naval warfare book The Price of Admiralty , military historian John Keegan postulates that eventually, almost all roles of surface warships will be taken over by submarines, as they will be
840-464: The knot is kn . The same symbol is preferred by the Institute of Electrical and Electronics Engineers ( IEEE ), while kt is also common, especially in aviation, where it is the form recommended by the International Civil Aviation Organization ( ICAO ). The knot is a non- SI unit. The knot is used in meteorology , and in maritime and air navigation. A vessel travelling at 1 knot along
875-485: The only naval units capable of evading the increasing intelligence capabilities (space satellites, airplanes etc.) that a fight between evenly matched modern states could bring to bear on them. However, thinking about importance of the submarine has shifted to an even more strategic role, with the advent of the nuclear ballistic missile submarine carrying Submarine-launched ballistic missiles with nuclear weapons to provide second strike capability. A modern submarine
910-686: The resumption of unrestricted submarine warfare , now to include deliberate attacks on neutral shipping, meant war with the United States but calculated that American mobilization would be too slow to stop a German victory on the Western Front and played a large role in the United States entering the war in April 1917. Once naval convoys were implemented, sinkings did not reach the German Imperial Admiralty Staff 's optimistic projections. The sinking of HMS Pathfinder
945-423: The role of submarines has developed independently of actual experience. The advent of the nuclear-powered submarine in the 1950s brought about a major change in strategic thinking about submarine warfare. These boats could operate faster, deeper and had much longer endurance. Their larger sizes also allowed them to become missile launching platforms. Nuclear power would allow submarines to have greater accuracy and
980-402: The situation was reversed, with US submarines hunting Japanese shipping. By war's end, US submarines had destroyed over half of all Japanese merchant ships, totaling well over five million tons of shipping. British and Dutch submarines also took part in attacks on Japanese shipping, mostly in coastal waters. Japanese submarines were initially successful, destroying two US fleet aircraft carriers ,
1015-650: The submarine has extended with the use of submarine-launched autonomous unmanned vehicles. The development of new air independent propulsion methods has meant that the diesel-electric submarine's need to surface, making it vulnerable, has been reduced. Nuclear submarines, although far larger, could generate their own air and water for an extended duration, meaning their need to surface was limited in any case. In today's more fractured geopolitical system, many nations are building and/or upgrading their submarines. The Japan Maritime Self-Defense Force has launched new models of submarines every few years; South Korea has upgraded
1050-518: The wars, navies experimented with submarine cruisers (France, Surcouf ), submarines armed with battleship caliber guns (UK, HMS M1 ) and submarines capable of carrying small aircraft for reconnaissance ( HMS M2 and Surcouf ). Germany was denied submarines by the terms of the Treaty of Versailles , but built some anyway. This was not legitimized until the Anglo-German Naval Agreement of 1935, under which
1085-427: The water moving around it. The chip log was cast over the stern of the moving vessel and the line allowed to pay out. Knots tied at a distance of 47 feet 3 inches (14.4018 m ) from each other, passed through a sailor's fingers, while another sailor used a 30-second sand-glass (28-second sand-glass is the currently accepted timing) to time the operation. The knot count would be reported and used in
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1120-429: Was described as a 'cat-and-mouse' game of detecting and even trailing enemy submarines. As the likelihood of unrestricted submarine warfare has diminished, thinking about conventional submarines has focused on their use against surface warships. The mere existence of a submarine may curtail surface warships' freedom to operate. To counter the threat of these submarines, hunter submarines were developed in turn. The role of
1155-748: Was primarily a fight between German and Austro-Hungarian U-boats and merchant vessels bound for the United Kingdom, France, and Russia. British and Allied submarines conducted widespread operations in the Baltic , North , Mediterranean and Black Seas along with the Atlantic Ocean. Only a few actions occurred outside the wider European-Atlantic theatre. The first round of major German submarine attacks on Allied merchant ships began in February 1915, but American civilian deaths, especially with
1190-514: Was the first combat victory of a modern submarine, and the exploits of SM U-9 , which sank three British cruisers in under an hour, established the submarine as an important new component of naval warfare. German submarines were used to lay naval mines and to attack iron ore shipping in the Baltic. The British submarine flotilla in the Baltic operated in support of the Russians until
1225-399: Was withdrawn in December 1939. Although mass attacks by submarine had been carried out in World War I, the " wolf pack " was mainly a tactic of World War II U-boats . The main steps in this tactic were as follows: With the later increase in warship and aircraft escorts, U-boat losses became unacceptable. Many boats were lost, and the earlier experienced commanders with them. In the Pacific,
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