A submarine (short for submarine ; military spelling submarine without a hyphen) is a boat that was built for underwater travel. Modern large submarines, which can have a mass of up to 26,000 tons , are also called submarines .
The term submarine specifically refers to a submarine used by the military. Civil submarines, whether commercial or research , are mostly referred to as submersibles .
Antiquity to the High Middle Ages
Man's desire to dive longer and deeper than his lung capacity allows is about as old as the desire to fly. That is why people have always been concerned with developing corresponding devices or instruments that should make this possible. From antiquity there are reports on this from Aristotle and Pliny the Elder . Even Alexander the Great is said to have attempted diving in the Mediterranean (see diving bell ). More detailed descriptions of a "Colymphas" (Greek for "diver") called and suitable for military purposes come from the 7th / 8th centuries. Century by Pseudo-Hieronymus in his Aethicus ascribed cosmography, a mixture of facts , myths , technical and geographical explanations as well as Christian wisdom.
A more recent description of a submersible vehicle in a story can be found in the heroic epic “ Salman and Morolf ”, written around 1180/90 .
13th to 16th centuries
The history of technical diving and the development of a submersible began in the 15th century. For example, in 1405 the Nuremberg war builder Konrad Kyeser designed his first diving suit in his Bellifortis factory . Roberto Valturio drew his submarine in 1472 and Leonardo da Vinci drew a one-man submersible in 1515.
17th to 18th centuries
These ideas were pushed further and in 1604 Magnus Ebene described the basic ideas and requirements for building a submersible for the first time in a book. The Dutch inventor Cornelis Jacobszoon Drebbel was the first to go beyond theory and in 1620 built the first maneuverable underwater vehicle - a leather-covered wooden rowing boat.
The Rotterdam ship was the first submersible in history designed for military use. It was constructed in 1653 by the French De Son in Rotterdam, South Holland.
On behalf of Landgrave Karl von Hessen-Kassel , the French physicist Denis Papin , who was also a professor at the Philipps University of Marburg , constructed a submersible in 1691, the first of which was destroyed in the Fulda in 1692 in the presence of a large crowd of onlookers. The second attempt with a burning candle, which reappeared burning, supposedly demonstrated that there was enough breathing air for people in the boat. Despite the failures, the idea of building a functional underwater vehicle had motivated tinkerers around the world. In 1772 the first underwater vehicle in Germany was tested in the Steinhuder Meer . It was made of wood and was shaped like a fish, which is why it was named pike . The boat dived for about twelve minutes. The American David Bushnell built the Turtle ("turtle") in 1776 , a construction made of iron and oak. It is considered the first real submarine, as two screws operated by hand cranks were used to drive it - in contrast to its two predecessors, which were driven by sails or oars on the surface of the water. In 1799 the mountain master Joseph von Baader described a construction for a two-man submarine.
The invention of the accumulator and electric motor enabled underwater propulsion that is independent of muscle power. The industrial production of steel also made an important contribution to the progress of submarine construction by replacing the light wood, which is prone to decay and parasites, with an extremely durable building material. In addition, with the invention of the torpedo by Giovanni Luppis in 1860, a useful weapon was also available for use from submarines.
Overall, the technical progress of industrialization made it possible to transform the submarine into a vehicle that was also interesting and useful for the navies of small states.
Robert Fulton's Nautilus
The American Robert Fulton designed the Nautilus submarine in 1801 . It had a hand crank drive for a screw, but new features were the rudders for rudder and depth control and a compressed air system to supply the four-person crew with breathing air. The Nautilus even caught the attention of Napoleon , but was ultimately considered too slow for military use.
Submarine trials in Russia
Kasimir Gawrilowitsch Tschernowski designed a streamlined all-metal submarine with an underwater rudder drive and oxygen tanks in 1829 . Karl Andrejewitsch Schilder built and tested the first Russian all-metal submarine in 1834, the further development of which was finished in 1847.
Wilhelm Bauer's fire diver
On December 18, 1850, the Bavarian artillery sergeant Wilhelm Bauer launched the first submarine built in Germany, the so-called Brandtaucher , in Kiel . Since the design was built under enormous cost pressure, the installation of diving cells was omitted. The diving process should be done by flooding water into the boat. During the first attempt at diving on February 1, 1851 in the Kiel inner fjord , however, the ballast shifted aft, with the flooded water also flowing into the stern. The boat sagged and more water seeped through the seams of the hull and the hatch. The boat sank to the bottom in seven meters of water. The three-man crew, including Wilhelm Bauer, waited until the internal pressure was as great as the external pressure, opened the entry hatch and floated to the surface, where they were rescued. The injured fire diver was only rescued on July 6, 1887. After various museum stations, the submersible now has its home in the Military History Museum of the Bundeswehr in Dresden. A model of the fire diver is in the Deutsches Museum in Munich. A full-size model of the fire diver's bow is in the Kiel Maritime Museum.
During the Civil War several hand-propelled submarines were built, including the CSS H. L. Hunley . On February 17, 1864, the USS Housatonic sank, making it the first submarine in the world to destroy another ship under combat conditions during wartime. Previous submarines had only sunk ships for test purposes. During this mission, however, the submarine and its eight-person crew were lost. It wasn't until May 4, 1995 that the Hunley was found by the National Underwater and Marine Agency (NUMA) and recovered in 2000.
Charles Bruns Plongeur
In 1863 the French Navy put into service the Plongeur, one of the world's first submarines that were not powered by muscle power. The boat used a piston engine powered by compressed air, could cover a distance of up to 9 km under water and was armed with a spar torpedo . The compressed air drive required very large tanks, which is why the submarine with a length of 43 m and a displacement of 426 ts was significantly larger than all other submarine designs of its time. Due to the drive concept and the short range, the boat could not operate independently and needed a steam-powered surface escort ship that had to tow the Plongeur to the target area and supply it with the necessary compressed air.
Narcís Monturiols Ictíneo II
On October 2, 1864, Narcís Monturiol launched the Ictíneo II, one of the first submarines with a mechanical drive. The boat was made of wood reinforced with copper frames and was completely covered with copper plates about two millimeters thick. It was powered by an engine that processed magnesium peroxide , zinc, and potassium chlorate .
Julius Kröhl's Sub Marine Explorer
The Sub Marine Explorer is considered to be the first functional submarine in the world , as it was the first boat that could surface again under its own power. The boat was manufactured in New York in 1865 by the German-American Julius Kröhl . The modern design with its streamlined hull, similar to today's boats, had a system of ballast chambers for diving and compressed air tanks for surfacing. The purpose of the boat was to collect pearls from the sea floor, for which it had three exit hatches downwards. After successful tests, it was dismantled into individual parts and shipped to Panama , where Kröhl dived for pearls. As early as 1867 he died, as did the entire team, presumably of diving disease . The ship was only rediscovered in 2006. Until then, the locals thought it was a destroyed Japanese micro-submarine from World War II. It lies aground off the coast of Panama and can still be reached on foot at low tide. Nevertheless, the boat is irretrievably lost, as the severe corrosion makes it impossible to salvage or restore it.
Military submarines in the late 19th century
Towards the end of the 19th century, the navies of various countries began to take an interest in submarines. The naval ministries of many countries - primarily Spain, France and the USA - announced competitions for submarines and had inventions and developments demonstrated. In 1878/79 the English priest and inventor George Garrett (1852–1902) built two submersible boats that were powered by carbon dioxide or steam. In 1881 the French Goubet introduced the electric motor as an underwater drive. In 1885 the Swede Thorsten Nordenfelt built a steam engine powered submarine together with Garrett, which was acquired by the Greek Navy. In 1886/87 two more 30-meter-long boats with a 250-hp steam drive followed, which Nordenfelt had built for the Ottoman Navy by the Barrow Shipbuilding Company , a pioneer in submarine construction . The boats stayed afloat while diving with a hemispherical cockpit. The boiler had to be closed, propulsion and navigation under water with compressed air. The 100-ton boats were 30.5 meters long and reached a speed of 6 knots above and 4 under water. They were armed with two torpedo tubes and two machine guns. The Abdul Hamid was the first submarine that managed to sink an old target ship with a torpedo. One problem was balancing the boat when launching the torpedoes.
Also in 1886 introduced the Spanish navy one of a naval officer named Isaac Peral designed electrically powered submarine called Peral in service, but could not evolve the primitive Akkumulatortechnik. From 1888, submarines were built in France and put into service in the navy. Henri Dupuy de Lôme and Gustave Zédé first developed a battery-powered submarine called Gymnote , which was built in Toulon. In the years that followed, other and larger boats were built there: The 48.5 m long Siren , followed in 1892 by a 36.5 m long boat called the Morse . Both boats were also battery-powered and armed with modern Whitehead torpedoes. The French Ministry of the Navy took the biggest step with the Narval developed by Maxime Laubeuf , which was built in 1899. It had a steam drive that charged the batteries when traveling over water. This boat became the basis of the Sirene class , four of which were put into service with the French Navy from 1900. In 1904, with the introduction of the Aigrette class , France replaced the steam drive, which was unsuitable for submarines, with the much more effective and reliable diesel engine.
The Irish emigrant John Philip Holland did pioneering work in the USA . First, from 1879, he constructed four submarines for the Fenian United Brotherhood , which wanted to use this new type of underwater weapon to defeat the Royal Navy and help Ireland achieve independence. Holland's boats were already powered by a gasoline engine when they were on the surface . In 1888 the US Navy announced a competition for submarine designs, which Holland won. Due to financial problems, Navy Holland was only able to send money to build a prototype from 1895. So the 40 m long plunger (also known as Holland V ) was first created in 1897 , but due to the ambitious goals of the Navy, it had numerous technical deficiencies, especially in the drive technology. Holland's next design, the Holland VI , which is significantly smaller at 25.4 m , was so impressed by the Navy in 1898 that the first six boats of the similarly designed Adder class were built from 1900 onwards. The other navies, especially the Royal Navy, were critical of the rapid development of submarines and initially refused to build submarines. In Russia, the first submarine, the Дельфин ( Dolphin ) developed by Ivan Bubnow , was launched in 1902.
1900 to 1930 - First World War
With the use of the Hunley in 1864, a growing interest in the use of submarines for war purposes began. In the German Empire, people remained cautious at first. The test submarine was built by Howaldt in Kiel in 1897 for his own account and, as a failure, was scrapped around 1902.
In 1902, a prototype of a 200-ton experimental submarine called the Forelle was built and intensively tested in Germany. The small submarine turned out to be quite interesting and fit for war, and three other boats of the same class were made for export to Russia. The use of military submarines was now also being considered in Germany, and finally, after a long period of hesitation, on April 4, 1904, the Reichsmarineamt commissioned the marine engineer Gustav Berling to design and build a submarine for naval warfare. Berling then turned to the Germania shipyard in Kiel. His design was based on the submarines exported to Russia. However, as there were some significant changes to the design, delivery of the submarine was delayed, and construction did not begin until April 1905. The main innovations concerned the pressure hull, the horizontal arrangement of the torpedo tubes and the drive, since instead of a potentially more dangerous gasoline engine, they wanted to use a petroleum drive, which, however, was not yet fully developed. On December 14, 1906, after several test drives, the first German military submarine was put into service by the Imperial German Navy as U 1 . Today U 1 is in the Deutsches Museum in Munich.
With the beginning of the First World War (1914-1918), submarines were used for the first time on a larger scale in trade wars ( merchant submarines ) or for military purposes (see submarine warfare ). The submarines almost always attacked surfaced and mostly sank merchant ships with the on-board cannon. The submarine was only supposed to submerge to avoid being chased because it was undetectable by enemy warships under the water surface during the First World War. Great diving depths were therefore meaningless.
The Imperial Navy valued the submarines very little at the beginning of the war and relied more on the large battleships. That changed when, on September 22nd, 1914, SM U 9 completely sank a blockade formation consisting of the three armored cruisers “ HMS Aboukir ”, “ HMS Cressy ” and “ HMS Hogue ” off the Dutch coast . On the armored cruisers, no one believed in a possible danger from German submarines and the torpedoes were not recognized, although they were powered by compressed air and left clear traces on the surface of the water. After the first explosions, the ship's command assumed mines as the cause and ignored reports of torpedo bubble trails. This misjudgment killed thousands of seafarers. The unexpected success made the German submarine drivers into heroes and favored the rapid expansion of the German submarine weapon. The reputation of the submariners towards the crews on the expensive capital ships, which were hardly ever used and achieved little success, increased considerably.
The German submarine weapon, which was only small at the beginning of the war compared to the submarine associations of Great Britain or France, grew very quickly and achieved a technical superiority over that of other countries. This was particularly true of the quality of the periscopes and torpedoes, which made them an extremely serious threat to the enemy’s fleets and merchant ships.
After the end of the First World War, the development of military submarines slowed down. Germany, now the largest manufacturer, was banned from development and production in the Versailles Peace Treaty . The victorious powers, however, saw no need to have a large offensive submarine weapon.
1930 to 1945 - World War II
Before the Second World War, the leadership of the German Navy was faced with a fairly strong Allied fleet at the start of the war. Since Great Britain and France appeared as the guarantor powers of Poland, it was hoped to achieve maximum sinking success with the relatively cheap to manufacture submarines. The submarines thus became the main threat to all trade routes. Above all, they were allowed to attack cargo ships with the aim of cutting off Great Britain as an island nation from urgently needed raw materials. Despite its technical and logistical limits and its small number of only 57 boats at the beginning of World War II, the submarine weapon was initially very successful. These successes convinced Hitler, who was originally skeptical, to agree to an intensified submarine construction program. More and more submarines were put into service and their number approached the basic demand of the commander of the submarines (BdU) Karl Dönitz for 300 boats for a successful blockade war against England. Some of the most successful of the commanders - the "Aces" - achieved enormous sinking rates. One of the most famous was Günther Prien , who in 1939 as commander of U 47 penetrated the bay of Scapa Flow , the heavily secured home port of the British Home Fleet , and sank the battleship HMS Royal Oak there .
Far more important, however, was the sinking of merchant ships. Nocturnal surface attacks by the submarines, which are difficult to see at night, were most successful. After the initial successes, the British economy quickly felt the effects of the many thousands of tons of sunk shipping space and extensive countermeasures of a tactical and logistical ( convoy system ) as well as a purely technical nature were initiated. The rapid progress in radar technology and the equipping of the security destroyers in the convoys with them made submarines that have emerged visible and combative, even at night. The submarine eluded by dipping, it was with ASDIC located and with depth charges to be fought.
Due to the low battery capacities, the predominantly used type VII and IX submarines could not separate themselves quickly enough from safety units under water and suffered increasing losses. The German development and production of the so-called "electric boats" of the types XXI and XXIII , which were far ahead of their time and were to be built in large numbers, were no longer used or only sporadically due to the end of the war. The Type XXI was the first submarine draft that was designed for predominantly underwater use. The boats of these types ran under water with e-engines faster than when surfaced with diesel engines and (thanks to high battery capacities and the possibility of snorkeling ) had the ability to operate submerged for a long time. It made all other submarine types obsolete in one fell swoop and became the starting point for all submarine development after 1945.
Italy also had a large submarine fleet (over 100 submarines in June 1940), and by the summer of 1940 the first Italian submarines were operating in the Atlantic. The ships of the Royal Italian Navy were in service until the surrender of Italy in September 1943. Unlike the Germans, however, they hardly fulfilled the expectations placed on them, since both the construction of the boats (too large tower, which could be seen from far even at night) and the training of the crews did not meet the requirements of the trade war. Overall, the Italian successes were only a fraction of those achieved by the Germans.
In contrast to the German submarines, the British submarines were not originally developed for use in the trade war on the high seas. They were mostly used to monitor ports and naval bases under German control. The existing H-Class and L-Class boats were single-hulled submarines, the designs of which date from the First World War. Two-hull ocean-going boats were among others the boats of the Thames and T-class. Of the modern two-hull A-class deep-sea boats newly developed by the Royal Navy, only the two boats Anchorite and Astute were completed before the end of the war , and they were no longer used in the war. From a military point of view, the British submarines operating in the Mediterranean were particularly important. They successfully torpedoed Axis ships from their bases in Malta, Gibraltar and Alexandria, which were supposed to transport supplies to the North African theater of war. A large part of the supplies for the German-Italian Africa Army was sunk based on information from the British Ultra Secret . The deciphering of the Enigma-M radio traffic enabled the British to locate enemy naval operations early and to take countermeasures. The successful conclusion of Operation " Ultra " , in which the British destroyer HMS Somali set out to hunt down German weather and supply ships in order to steal their encryption machines and keys, provided this opportunity at the end of May 1941.
Only towards the end of the war did Soviet submarines intervene in the war in the Baltic Sea, where they threatened German ship transport to and from the East Prussian basin. They caused three of the most devastating shipping disasters of all time: On January 30, 1945 S-13 (С-13) sank the Wilhelm Gustloff , killing more than 9,000 people. On February 10, S-13 sank the Steuben (approx. 3,400 dead), on April 16, the Goya fell victim to the Soviet submarine L-3 (Л-3) (over 7,000 deaths).
During the Pacific War, both Japan and the USA had significant submarine fleets, in addition to which some British and Dutch submarines were also in service in this theater of war. While the Japanese naval command saw the main task of their submarines as securing their own surface naval operations and fighting enemy warships, the Americans concentrated on sinking merchant ships. In Japan there was also the development and use of small submarines, which were brought close to the target area by the large "underwater cruisers". Japan also built underwater aircraft carriers that could accommodate up to three aircraft in a pressure hull. The plan was to use these aircraft to bomb the locks of the Panama Canal or San Francisco, for example. At the beginning of the war, the Japanese merchant fleet had a shipping capacity of 6 million GRT. Of these, 5,053,491 GRT (1178 ships) had been sunk by the end of the war. The bottlenecks in Japanese supplies as well as in Japan's raw material supply resulting from these losses contributed to the Allied victory in the Pacific. The Japanese submarine weapon suffered high losses due to the use of sonar among the Americans; out of a total of 190 submarines, 127 were lost. The Japanese submarines were often attacked before they could even approach the target. The US Navy lost 52 submarines, which was almost 16% of all boats in service.
Although the submarine war had turned out to be very costly, the strategic value of the submarine weapon gained more and more importance in the Cold War . The aim of the submarine development was now to improve the weaknesses of the models of the Second World War. This was particularly aimed at extremely long - and also fast - underwater journeys and great diving depths.
The development culminated in the construction of nuclear-powered submarines , which fulfilled the required long diving times. The United States led the way in this development, and on January 21, 1954, the first nuclear-powered submarine, the USS Nautilus , was launched. On August 3, 1958, it was the first watercraft to pass the geographic North Pole while diving under the Arctic .
The non-nuclear-powered research submarine Trieste reached the second deepest point on earth at 10,916 meters on January 23, 1960.
In the years that followed, the submarines developed rapidly. They were built bigger and more powerful. Since there were hardly any spectacular "public" developments in submarine technology to report and the submarine weapon was classified as very secret overall, the public only learned something about "disasters" in the following decades the modern submarines.
Since the Second World War, submarines have made headlines primarily through spectacular accidents:
- On April 9, 1963, there was an accident in the Atlantic. The USS Thresher broke into six parts while attempting a deep dive. Today it is assumed that a high pressure line burst and so the ballast tanks could no longer be blown out in time. However, the prototype of a hunting submarine had already shown control problems when intercepting the ship at high speed at great depths. There were no survivors.
- An important incident for the German public occurred on September 14, 1966 with the sinking of U-Hai of the German Navy, which killed 19 crew members.
- On January 27, 1968, the conventional French submarine Minerva of the Daphné class with 52 crew members disappeared in the Mediterranean at Cape Sicié due to unexplained circumstances during an exercise.
- On March 8, 1968, an explosion occurred on board the Soviet submarine K-129 , whereupon the submarine sank. 86 team members died. This was also the start of the Azorian project - the secret attempt by the CIA to salvage the Soviet submarine from a depth of over 5000 meters.
- In May 1968 the nuclear powered USS Scorpion disappeared on a voyage from Gibraltar to Norfolk near the Azores. To date, there has been various speculations about the disappearance, from a collision to an uncontrolled torpedo. Most likely, a torpedo battery malfunctioned, which led to an explosion inside.
- On March 4, 1970, the conventional French submarine Eurydike , also a Daphné-class boat , with 57 crew members disappeared in the Mediterranean near St. Tropez for unexplained reasons.
- On October 3, 1986, the fuel of one of the rockets exploded in the Soviet submarine K-219 around 680 nautical miles northeast of the Bermuda Islands in the Atlantic Ocean , and the rocket chamber was filled with water. The K-219 then emerged and floated on the surface for three days. On October 6th, the submarine finally sank for an ultimately unexplained cause. Four crew members died, the rest of the crew was saved.
- On August 12, 2000, the Russian submarine K-141 Kursk sank as a result of several explosions of its own torpedoes with its entire crew of 118 men. 23 crew members initially survived and were able to save themselves in the rearmost section, where the emergency exit hatches were also. After a few hours the oxygen in the air was so exhausted that all 23 of them suffocated.
- At the end of December 2011 there was a major fire on the rubber hull of the nuclear-powered Russian submarine Yekaterinburg (after the city of the same name from the 667BDRM class).
- On August 14, 2013 there was an explosion on the INS Sindhurakshak lying in the port of Mumbai , whereupon the submarine sank. 18 people were killed.
- On November 15, 2017, the Argentine submarine San Juan (S 42) disappeared under previously unexplained circumstances off the Argentine coast in the South Atlantic . In his last radio message, the commander reported a smoldering fire in the area of the bow batteries. Three hours later, hydrophones recorded an explosion in the South Atlantic.
Even after the Second World War, there were isolated acts of combat involving submarines. The first took place with conventional submarines in the Bangladesh war of 1971, when India intervened in the war between Bangladesh and Pakistan. On December 9, 1971, the Indian frigate INS Khukri was sunk by the Pakistani submarine PNS Hangor , a boat of the French Daphné class . Eleven years later, a nuclear submarine attacked a warship for the first time: On May 2, 1982, the Argentine cruiser General Belgrano was sunk by a torpedo from the British submarine HMS Conqueror during the Falklands War .
In addition, submarines are used for reconnaissance purposes. An international scandal occurred in October 1981 when the Soviet submarine W-137 ( whiskey class ) armed with nuclear torpedoes ran into an archipelago off the Swedish naval port of Karlskrona and was seized by the Swedish navy . The Soviet leadership then denied an espionage operation against neutral Sweden and attributed the incident to a navigation error.
State of the art
Since after the Second World War the great powers switched almost entirely to the use of nuclear submarines, it was left to smaller navies (mainly Germany, Italy, Sweden and the Netherlands) to further develop the technology for conventionally operated submarines. The current state of the art is the introduction of drive systems that are independent of the outside air , for example in the form of fuel cells , circulation drives or Stirling engines . Examples are the German submarine class 212 A , the first U 31 of which was handed over to the German Navy in March 2004 , and the Swedish Gotland class , whose boats have been in service since 1996. U 31 is the first submarine to have a hybrid drive consisting of an electric and a fuel cell drive and enables weeks of diving without the disadvantages of a nuclear drive (pump and turbine noise, heat emission (heat drag), safety risks). This drive gives the boats a speed of 12 knots surfaced (≈ 22 km / h) and 20 knots submerged (≈ 37 km / h). The nuclear-powered submarines of the most widely built American Los Angeles class reach 20 knots when surfaced and over 33 knots when submerged.
Static and dynamic diving
Submarines can not only swim on the surface of the water, they can also dive completely underwater. When submarines float on the surface of the water, like normal ships, they are lighter than the surrounding water. For a dive trip, they increase their density by flooding ballast tanks with water. In this way, when their mass is greater than that of the displaced water, they sink below the surface of the water. This process is called static diving .
During the dive , the aim is to ensure that its total mass is equal to that of the displaced water. Then they float in the water according to the Archimedes' principle , without needing energy to hold the depth. However, this state is never exactly reached. On the one hand, even the smallest differences between the submarine mass and that of the displaced water have an effect. On the other hand, the density of the surrounding water changes continuously due to changes in the salt content, the amount of suspended matter (plankton) and the temperature of the water. So the submarine always has a tendency to rise or fall. It must therefore be controlled are. To do this, water is let into or squeezed out into control cells.
A well steered submarine maneuvers underwater in the vertical through dynamic diving . To do this, it generates dynamic lift or downforce while moving forward with the help of horizontal down rudders . The down elevator act like the wings of an airplane. In historical submarines, a pair of down rudders was usually attached to the fore and aft. Modern submarines often carry the forward thrusters on the side of the tower.
The first underwater vehicles from the 15th to 18th centuries consisted almost exclusively of wood and were - if at all - only held together by iron frames or nails. The boats were often made in such a way that another wooden boat was symbolically mounted up the keel on a normal wooden boat. As a rule, the wooden planks of such underwater vehicles were sealed with pitch and, in addition to being sealed, completely covered with a skin of leather. These “submarines” were mostly single-hulled boats in which the diving cells were attached within the pressure hull . Since the cells were in contact with the outside water, they too had to be built pressure-resistant and appropriate pumps had to be available.
Only when it was technically possible in the middle of the 19th century to attach the propeller and rudder to the fuselage in such a way that the vehicles could be moved and steered independently without being pulled on the surface by an escort vehicle, the design of the fuselage also changed . Now the construction of the hulls was increasingly reinforced with metal inserts and at the beginning of the 20th century the first submarines were built with a complete steel hull.
Diving cells and tanks were soon moved out of the pressure hull; This resulted in single-hulled boats with saddle tanks . Out of the pursuit of good seaworthiness when sailing above the water, the two-hulled boat emerged , in which the diving cells were placed around the cylindrical pressure hull . The boat received a second shell in the shape of a boat. Since this was under the same pressure inside and outside when diving, it did not need to be particularly strong. The weight changes caused by fuel consumption were countered by floating the fuel oil in non-pressure-resistant, open-bottom bunkers on seawater.
With the increasing technical development after or during the Second World War, the surface aspect of the submarine gradually disappeared. The boats were initially given a hydrodynamically clean, smooth shape, and American developments relating to the test submarine USS Albacore ultimately led to the teardrop shape with a cylindrical center piece, which is predominantly built today. This is usually achieved by streamlining the cylindrical pressure hull with free-floating structures fore and aft. The upper deck and the tower are also free-floating, but there is no continuous second shell. The boats common today are therefore neither single-hulled nor double-hulled boats and are sometimes called one-and -a-half- hulled boats .
In modern boats, the fittings such as crew quarters, command center, drive, etc. are increasingly acoustically decoupled, that is, suspended or attached to the hull with passive and active damping and intermediate supports. A plurality of conventional propellers by a single vielflügligen sickle propeller or a jet propeller or pump jet replaced. The aim is a further minimization of the noise emission to the surrounding water and the silence of the boat, which makes it more or less “invisible” (see stealth technology ). Reports on magnetohydrodynamic drives ("caterpillar drive" or MHA-like technology) are more likely to be classified as fiction .
The following graphic gives an impression of the size of older and more modern submarines compared to a Boeing 747 passenger aircraft (for the abbreviations see Military Classification of Submarines ):
The pressure hulls of modern military submarines normally withstand the water pressure at a depth of 600 meters. Given the depth of the oceans, this means that they can actually only operate just below the surface of the water. Some Soviet nuclear submarines had pressure hulls made of titanium and were able to dive about 900 meters deep. Project 685 submarines reportedly even came under 1,200 meters. Special civilian deep-sea submarines, as well as bathyscaphs, are able to reach any point on the seabed.
Submarines must be able to maneuver in three dimensions.
- Diving cells : tanks that are filled with water to increase weight when diving and with air to surface. The beginning of the filling of the buoyancy cells with air, sometimes the whole process, iscalled blowing . Blowing out means completely emptying the cells when the boat has broken through the surface of the water, using diesel exhaust fumes or a special electric fan to save compressed air.
- Control cells : The control cells are used to fine-tune the boat's mass in order to maintain the state of suspension in the water, and are therefore always partially filled with air so that water can be flooded in. There are usually several control cells in which this air cushion is operated under different pressures in order to be able to carry out coarse and fine changes in mass. The control cells are made pressure-resistant.
- Torpedo cells : When the boat launches weapons (mostly torpedoes), the lost weight must be compensated. There are separate torpedo cells for this purpose, which can be flooded very quickly when fired. Since a torpedo volley can weigh ten tons and more, these cells are quite large.
- Undercarriage cells: The task of these special diving cells is to increase the weight of the submarine as quickly as possible in order to achieve faster alarm diving times. These were sometimes less than 30 seconds in combat boats in World War II. This technology is no longer used in modern nuclear submarines, as they usually only have to dive once during their use and only reappear after months. You may therefore need several minutes to dive.
- Trim cells : They are used to steer the boat with zero weight and on a level keel. The trim system contains a fixed amount of water that can be pushed forward or backward. This is done using compressed air in the opposite tank or with a pump in the trim line; the latter has the advantage of saving compressed air. The trim cells are generally not pressure-resistant (in contrast to the control cells).
- Down elevator : You take care of the fine-tuning while submerged. The arrangement of the forward depth rudder varies greatly in modern submarines. Depth rudders attached to the tower are not able to support the diving process and make it difficult to ascend in icy water. Small submarines sometimes have dynamic depth control; i.e., they only steer with down rudders. This technology is mainly used in unmanned submarines and in model making.
For fine-tuning the periscope depth see: Papenberg instrument .
In principle, all propulsion systems that can be used for ships can be used for travel over water. Ordinary ship assemblies ( diesel engines , gas turbines ) are internal combustion engines and require large amounts of oxygen for the combustion process, which can be sucked in from the air when traveling over water or snorkeling.
- Normal steam engines have the serious problem that they are very massive and voluminous and the process of steam generation is sluggish, i.e. That is, before it can be used, you have to heat it up for a long time, and then you cannot simply turn off the steam generation again, which is hardly useful for a submarine that is supposed to dive up and down quickly.
- Petroleum and gasoline engines basically meet the requirement of being able to provide high power very quickly with low weight and also to be able to be switched off again quickly. In practice, however, the irritating and highly flammable vapors of the fuel have proven to be problematic. Engine fires and deflagrations in the boats occurred again and again at the beginning of submarine development, and the crews suffered from considerable irritation.
- Diesel engines have long proven to be the most suitable unit to propel the boat across water. Since the invention of a snorkel for submarines, the diesel engine can even be used at periscope depth . However, the boat is bound to a very shallow diving depth.
However, the actual drive problem arises when diving, as there is not enough air available for the operation of internal combustion engines and exhaust gases can no longer be discharged at greater depths. Air-independent drives must therefore be used.
- Muscle power: The first submarines were driven by hand with a foot crank, pedal wheel or hand crank. Mention should be made here of the Brandtaucher , Bushnell's Turtle , Fulton's Nautilus and the Hunley of the southern states in the Civil War .
- Steam drive: Experiments with a chemical-based steam drive in so-called fleet submarines based on piston engines or turbines were soon abandoned as the wrong way. This drive can still be found today in a modified form in torpedoes .
- Electric drive with accumulators : Coupled with an internal combustion engine that charges the accumulators when sailing above water or snorkeling, it is still the drive for almost all non-atomic submarines. This combined diesel-electric drive already emerged as the standard during the First World War. Also suitable as the sole drive for small submarines, for example research submarines and diving vehicles, but also for robots and torpedoes.
- Walter drive with highly concentrated hydrogen peroxide : During the Second World War, there were tests on the German side with a turbine drive that was independent of the outside air and based on highly concentrated hydrogen peroxide in conjunction with diesel fuel. The hydrogen peroxide was in the Zersetzerkammer over as catalyst acting manganese dioxide (manganese dioxide) directed where it decomposes rapidly under very strong heat, then Diesel fuel was injected into the hot oxygen-containing vapor which ignited immediately itself. The resulting gas-steam mixture then drove a turbine. These were the so-called Walter submarines, named after their designer Hellmuth Walter . The advantages were longer diving times and significantly higher underwater speeds. The drive was not taken over into series production; The main results of boat development, such as the smooth hull shape, were still used during the war ( Type XXI , Type XXIII ) and noticeably influenced all post-war developments. After the Second World War, Great Britain continued research on the Walter drive, but this extremely powerful drive was soon abandoned due to the dangerousness of the chemicals used and the high fuel consumption. A fault in the hydrogen peroxide drive of a torpedo is said to have led to the sinking of the Russian submarine K-141 Kursk .
- Closed loop diesel drive : The diesel engine (or another internal combustion engine ) isoperated under waterwith an oxygen supplier, such as liquid oxygen (LOX) or hydrogen peroxide . The combustion gases are washed (a good part of the carbon dioxide is removed by dissolving it in water) and the missing oxygen is added again before re-combustion. CCD (Closed Cycle Diesel) technology was successfully tested in the mid-1990s by TNSW on submarine U1 - which was also used as a test vehicle for the fuel cell - but was unable to establish itself on the international market.
- Nuclear power : In nuclear submarines are used as main propulsion machinery steam turbines. The steam is in turngeneratedby a nuclear reactor . An electrically operated auxiliary drive can often be coupled to the propeller shaft for maneuvering. Auxiliary steam turbines generate electricity via generators, which in turn is used to supply electrical equipment. Sinceoxygen and drinking water can also be obtained from seawaterthrough electrolysis , nuclear-powered submarines can remain under water for months.
- Stirling engine : In some submarines of the Swedish and Japanese navies, possibly also in the navy of the People's Republic of China, external air-independent Stirling engines are used, which improve noise camouflage due to their particularly smooth running. Stirling engines work on the basis of a temperature gradient, so no exhaust gas is produced and does not have to be emitted.
- MESMA drive : This cycle steamturbine drive is a French development. The actual steam cycle is separated from the ethanol combustion cycle, analogous to the large boiler-turbine ship drives. Liquid oxygen (LOX) replaces the hydrogen peroxide used in Walter drives, the turbine no longer acts directly on the propeller shaft, and a generator ensures acoustic decoupling. Such systems are used in the Spanish and Pakistani navies.
- Fuel cells : These boats are also powered by electric motors . In the fuel cell, however, the energy in a chemical fuel is not generated via the detour of combustion, but catalytically converted directly into electrical current, which then drives the electric motors. The development of this technology began towards the end of the Second World War. The interest in using fuel cells for submarines is therefore much older than that of the automotive industry. Today, this type of propulsion is probably the most advanced, alongside nuclear propulsion. The independence from atmospheric oxygen as well as a minimum of moving parts that cause noise, long dwell times under water and the low level of waste heat meet the requirements of modern military submarines. With the classes 212 A and 214 , fuel cell submarines of German design have meanwhile been introduced into some navies.
- Magnetohydrodynamic drive (MHD drive): Here, a continuously changing magnetic field is placedaround the submarine or through a drivenozzle. Electromagnetic effects ( Lorentz force ) on the conductive salt ions in the sea water create a water jet that drives the submarineaccording to the recoil principle . In practice, this drive technology was used in the 1990s by the Japanese company Mitsubishi on the testvehicle Yamato 1 , but only achieved a disappointing performance of 8 knots (15 km / h).
Even after the outer hatches have been closed for diving, the breathing of the crew and passengers inside the boat releases carbon dioxide (CO 2 ) and consumes oxygen . In order to maintain the breathable air in the boat, oxygen must be supplemented and carbon dioxide removed as a result.
Depending on the air space inside the boat, the number of people and their physical activity, the CO 2 content of the air you breathe increases within a few hours from the current outside air concentration of around 0.04% to an acceptable 1.0… 1.5%. In about twice the time, the oxygen content of the air drops from an initial 21% to an acceptable 17%. A higher CO 2 concentration of 4% can only be endured for a short time, 5% is poisonous. Without air renewal, it is therefore necessary after a few hours to supply fresh air through ventilation or a mechanical device which exchanges the outside air with the inside air of the boat. Otherwise, in order to avoid poisoning the people on board, filters that bind the CO 2 gas must be used after a while . In addition to conventional filters, which lose their effectiveness over time, modern systems offer a circuit for continuous CO 2 cleaning, for example with the help of a "scrubber" system in which heated monoethanolamine is used to bind the CO 2 from the air and to transport it to a closed tank, where it is released again when the monoethanolamine cools.
The oxygen required by the crew and passengers of a submarine in diving operation must also be carried on board or generated. As early as 1620, Cornelis Jacobszoon Drebbel developed the idea of supplementing oxygen by using potassium nitrate , which when heated releases oxygen. Today it is common to carry an additional supply of oxygen in gas cylinders, which can be dosed more precisely.
Air renewal systems appeared around 1900. The first submarine of the Imperial Navy SM U 1 had an air renewal system from the Drägerwerk Lübeck. Dräger had developed self-contained breathing apparatus for mining. The principle used here was transferred to rooms such as the interior of a submarine. The following submarines, at least up to SM U 12 and later boats, were also equipped with Dräger systems.
In the case of submarines powered by nuclear energy , the oxygen consumed by the crew can also be replaced with oxygen generated on board. For this purpose, energy from the drive system is used to split water (H 2 O) into its components - hydrogen and oxygen - by means of electrolysis , so that surfacing to exchange air is no longer necessary.
Other air pollutants, such as vapors, smells and fats, must also be removed by filters when diving. Another method here can be the splitting of undesired molecules in the breathing air in systems for catalytic combustion , which in turn consume oxygen.
When a submarine inflates all of its diving and control cells with the compressed air on board, it initiates a rapid ascent process known as emergency ascent. Compared to quasi-static (normally slow) ascent, a comparatively large part of the boat breaks through the water surface due to the inertia.
When the submarine rises at a steep angle to the surface of the water, the ascent process is fastest. Examples:
- In October 1986, the commander of the nuclear-powered Soviet submarine K-219 decided to emerge at a depth of approximately 350 m. Just two minutes after an explosion on board, the K-219 broke the surface of the water.
- The USS Greeneville (SSN-772) rammed a Japanese fishing boat in a simulated emergency surfacing in 2001.
- An emergency submarine can be seen in the film Hunt for Red October .
Many states have military submarines, but exact data on the numbers are often secret.
The strength of submarines compared to surface ships is that they operate covertly and are difficult to spot.
Since submarines cannot be detected optically because the sea is dark at greater depths and radar does not work underwater, they can only be localized acoustically at greater distances , and at short distances also through the warming of the water by the drive or a distortion of the Earth's magnetic field through the steel shell.
That is why particular care is taken in the design to ensure that a submarine is as quiet as possible. This is achieved through a streamlined hull, specially shaped propellers, acoustic decoupling, in particular of the piston engine and the outer shell (including screw), and insulation of the outer shell with elastomer.
Duties and types of submarines
The original task of submarines was to fight surface ships. In this role, the submarines gained their importance in both world wars. With the beginning of the nuclear age, two other main tasks were added: Strategic submarines were equipped with nuclear missiles and served as a nuclear deterrent . They formed part of the so-called first strike capacity , but could also be included in the second strike capacity , which should survive an enemy attack on one's own country and be ready for a counterstrike. At the same time, special hunting submarines were developed to hunt down enemy strategic submarines. For both tasks, nuclear-powered submarines were primarily, but not exclusively, used. Recently, non-nuclear, air-independent propulsion has been developed for hunting submarines. Boats with the fuel cell drive developed in Germany are currently being procured from the German Navy and some of its allies. In the German Navy, it is the class 212 A submarines that are gradually being put into service.
In addition to these classic tasks, reconnaissance with submarines has gained in importance. Due to their ability to operate unseen and to be able to listen very far with acoustic sensors, submarines offer the advantage of being able to gather important information, especially in scenarios below the threshold of open conflicts. Another special task is the deployment of combat swimmers from the submarine. Both tasks can be performed by conventional or special submarines.
Submarines differ in different military or civilian types, depending on the purpose and the mission of the respective submarine. However, since submarines are mainly used for military purposes today, the proportion of various types of submarines used for military purposes predominates in the following list:
- Nuclear submarines can travel long distances and are often very large (up to 48,000 tons displacement ).
- Strategic missile submarines (English SSBN / French SNLE) were used for nuclear deterrence (see Ohio class and Vanguard class ). The first submarines of this type were created by converting attack submarines (see George Washington class ). The first plans were based on the German A4 (V2) missiles and the prepared use of US A4 (V2) replicas against Japan. In the course of disarmament, there were considerations to use some boats for conventional guided missiles or to transport special forces.
- Assault / chase submarines (also known as tactical submarines) are usually armed with torpedoes to attack other ships or submarines. They can also be equipped with cruise missiles for attacking land targets or worthwhile sea targets (such as aircraft carrier combat groups ). If this is their main task, they are known as cruise missile submarines . Hunting submarines exist with a variety of forms of propulsion. Nuclear-powered hunting submarines are used to combat enemy submarines. Hunting submarines are the most effective weapon against submarines with ballistic missiles, as these often operate submerged under the ice. In addition, the sensor range of submerged submarines is far greater than that of surface ships or aircraft. Hunting submarines are primarily characterized by their high speed. The Russian Alfa-class submarines are among the fastest submarines in existence.
- Supply submarines or submarine tankers (World War II): The task of these boats in World War II was to supply other submarines at sea with supplies ( dairy cows ). The large, but also clumsy and almost unarmed boats were an easy target.
- Commercial submarines : They were only used in World War I. The only commercial submarines ever built and used that belonged to a civil shipping company were the U "Deutschland" and U "Bremen". During the Second World War, only military submarines of type IX D - the so-called monsoon boats that operated in the Indian Ocean - were loaded with rubber, tungsten, tin, quinine and opium for the return journey to Germany in Penang. They broke through the Allied naval blockade. In the 1970s there were plans to use large submarines to transport crude oil to the Arctic.
- Submarine miners : Even in World War I, specialized submarines were used as mine layers. As early as the Second World War, ground mines specially developed for this purpose could be laid over the torpedo tubes (so-called torpedo mines). Today this function is ensured exclusively by the torpedo tubes or special outer mine belts.
- U-cruisers were developed in the First World War and in the interwar period for the trade war according to the price order . In addition to torpedoes, they were armed with powerful artillery, carried dinghies and even observation planes. The largest submarine before World War II, the French Surcouf , was such a submarine. Aircraft were used on Japanese submarines to explore large areas - plans to bomb the Panama Canal in World War II by six Seiran aircraft from the submarines I-400 and I-401 existed, but were not carried out because the two submarines were not carried out were not ready for use until the early summer of 1945. The less successful fleet submarines were primarily built to be steam -powered in association with the regular fleet. The idea of underwater aircraft carriers is being taken up again by the USA with the DARPA / Hydra program for drone carriers.
- Coastal submarines are usually built smaller and therefore more maneuverable. They operate primarily with conventional propulsion in the area of the continental shelf .
Other military submarine tasks :
- Reconnaissance: Coastal reconnaissance, reconnaissance with a towed helicopter ( wagtail ) or on-board aircraft (see above)
- Development: Testing of new techniques, such as the USS Albacore , the German Walter boats and the French Gymnote
- Transport: combat swimmers, manned torpedoes, supplies, courier services, etc.
- Rescue: Rescue or salvage of crashed submarine crews.
For the designation of submarine types, the standards of the US Navy are mostly used in the specialist literature. These provide information about the propulsion and purpose of a submarine.
The former Soviet and today's Russian Navy uses a similar system, which allows combinations of the abbreviation for submarine (PL) supplemented by abbreviations for drive type and type of armament:
- PL (ПЛ) (Podvodnaja Lodka, Подводная Лодка, submarine)
- PLA (ПЛА) (Podwodnaja Lodka Atomnaja, Подводная Лодка Атомная, nuclear-powered submarine)
- PLARB (ПЛАРБ) (Podwodnaja Lodka Atomnaja Raketnaja Ballistitscheskaja, Подводная Лодка Атомная Ракетная Баллистическая, nuclear-powered submarine with ballistic missiles)
- PLARK (ПЛАРК) (Podwodnaja Lodka Atomnaja Raketnaja Krylataja, Подводная Лодка Атомная Ракетная Крылатая, nuclear-powered submarine with guided missiles)
For boats with diesel engines the following results:
- DPLRB (ДПЛРБ) (Diselnaya Podwodnaja Lodka Raketnaja Ballistitscheskaja, дизельная подводная лодка с баллистическими ракетами, diesel submarine with ballistic missiles)
- DPLRK (ДПЛРК) (Diselnaya Podwodnaja Lodka Raketnaja Krylataja, дизельная подводная лодка с крылатыми ракетами, diesel submarine with guided missiles)
Submarines have various sensors and observation devices that they can use to locate objects.
In modern submarines, a radar sensor or periscope can be extended from the top of the tower on or directly below the surface of the water :
- The periscope allows an optical inspection of the surroundings at close range, but can be seen by the opponent himself or located using his radar reflection. Modern submarines often have a switchable night vision device installed in their periscopes so that they can also function in the dark.
- The submarine's radar can be actively used to detect objects through the reflection of transmitted radio waves. Since an opponent can locate these transmitted signals and thus also determine the position of the boat, antennas of submarines can now also be deployed, which can passively recognize the radar signals of external transmitters.
Under water, a submarine can only locate other ships acoustically through their noise emission. The corresponding sensors are called sonar sensors .
- Objects can be located passively via hydrophones based on the noises they generate, or the submarine itself actively emits a sound impulse and recognizes the position of an object from the reflection of this impulse. The emitted noise pulse can, however, be recognized by other hydrophones and the position of the submarine can thus be determined.
The importance of sonar sensors made them play an increasingly important role in the design of submarines. In order to be affected as little as possible in their performance by background noise, hydrophones must be mounted as far away as possible from the propeller and the propulsion system, so that the main sensor of the sonar is in the bow of a submarine. These sensors in the bow are made up of many individual hydrophones that are mounted in a cylindrical or spherical structure.
Since the noise of the engine itself makes it difficult to locate noises behind the boat, in many cases a so-called towed array (TAS) can be pulled behind the submarine on cables several hundred meters long . This has some advantages, but also disadvantages. This increases the sensitivity of the passive sonar considerably, since on the one hand significantly more hydrophones can be attached to the towing cable, and on the other hand the distance to the drive of the submarine reduces the background noise. This leads to a significantly increased sensitivity, which ensures an increased listening range and direction finding accuracy. A disadvantage of the towing sonar is its length (some up to half a kilometer long) and its weight. The maneuverability of the submarine is limited as a result, as is the speed, the latter being the lesser problem, since the towing sonar is only used when traveling slowly or at crawling speed . The retrieval time of the towed sonar depends on the length of the cable and can take longer than a minute, which can be "too long" in critical situations. If the speed has to be increased quickly in a crisis situation, a tight turning maneuver has to be initiated or the diving depth has to be changed rapidly, there is often no other option than to cut the towing sonar.
Passive location protection
Basically, the smaller and quieter it is, the more difficult it is to locate a submarine. Diesel-electric powered submarines often have advantages over the much larger nuclear submarines when submerged. The main advantages of nuclear submarines are their endurance and speed. However, high speeds reduce the sensor range considerably and increase the noise level. In addition, the high temperature of the reactor causes numerous problems. In modern nuclear reactors, the cooling can be done solely by convection with low power output . Otherwise, cooling water pumps are required, which generate noises that spread over the hull into the water and can be localized there. The waste heat from the cooling water of nuclear reactors can even be located by satellites. Another possibility to dampen the noise of a submarine is to build all the machines on a free-swinging, rubber-mounted platform in order to reduce the noise transmission to the rest of the hull. Specially shaped propellers ensure that cavitation noises are minimized .
In addition to the attenuation of intrinsic noises, measures are also used to make it more difficult to locate using enemy sonar . For example, an opanine cover - a rubber coating around 4 mm thick - dampens the sound reflection in the frequency band between 10 and 18 kHz up to 15%. The effect of the protective agent is strongly dependent on the salt content, air content and temperature of the water. This technique was first used in 1943 on the German U 480 . Due to the special design of the boat hull, the sonar reflection area of a submarine can be reduced so that an incident sonar pulse is deflected or scattered and only a very weak echo is reflected back in the direction of the transmitter.
The hull of some submarine classes is made of non-magnetizable steel . This makes localization by detecting the distortion of the earth's magnetic field generated by the submarine as good as impossible.
Since the Second World War, radio monitoring devices have also been used on submarines, which are intended to warn the submarine's crew of possible radar location by enemy air and sea targets.
Active location protection, active countermeasures
One means of protection consists in the ejection of decoys (" Bolden "). A decoy can be a float containing calcium hydride (CaH 2 ) and can be ejected from the submarine. It floats in the water and creates hydrogen bubbles that are supposed to simulate a decoy for active sonar location , behind which the endangered submarine can run. Another means is the ejection or dragging of decoys, which imitate the noise of the submarine or its propulsion and thus mislead the passive sonar location of approaching torpedoes.
Communication with submerged submarines is problematic. Only very long-wave radio signals (VLF, Very Low Frequency, long-wave ), such as those from the Rhauderfehn marine radio station , can penetrate about 10 to 30 meters into the sea water. During World War II, the Navy used the Goliath long-wave transmitter on 16.55 kHz (main frequency) to transmit messages to submerged submarines.
Today, only the superpowers have the ability to send a small amount of data to submarines even at depths of up to 300 meters. This happened on 76 Hz (USA, long-wave transmitter Sanguine ) and 82 Hz (Russia, long-wave transmitter ZEVS ), i.e. on SLF ( Super Low Frequency ). The only possible low data rate allowed only a kind of "call signal" to request submarines, for example, to ascend up to approx. 15 meters below the water surface in order to receive messages there on long waves (VLF, 3–30 kHz) with a higher data rate, without having to position antenna, buoys etc. above the water surface. The U.S. uses the Cutler naval radio station for VLF transmission . However, activities in the SLF area were discontinued by the USA in September 2004 and no activities have been observed on the Russian 82 Hz frequency for a long time.
If large amounts of data need to be exchanged or the submarine not only has to receive but also send, it is forced to penetrate the water surface with conventional antenna masts or buoys. However, this makes it easier to locate the submarine, which is to be kept hidden from the military enemy. Long messages to a submarine are stored on a satellite and downloaded (in seconds). For a submerged submarine, there is also the option of raising a radio buoy with a stored message, which is then sent to a satellite, for example. This is also the standard procedure in emergency situations where the boat has sunk to the bottom and outside help is needed. Attempts to solve the communication problem using satellite-based lasers, which can penetrate seawater to some extent, were likely abandoned after the end of the Cold War.
The scientists Maurice Green and Kenneth Scussel from the US Office of Naval Research (ONR) also succeeded in 2007 in developing an underwater GPS system that should enable the precise position of submarines to be determined. The system is able to use acoustic signals and computer calculations to locate the position of submarines and, in the future, possibly also of divers . For this purpose, firmly anchored, precisely positioned GPS base stations are set up on the seabed. A submarine can "communicate" with the GPS base station on the ocean floor using sonar pulses. With the response signal from the GPS sea floor station, which calculates the exact depth and bearing angle of the received sound pulse, a computer system on board a submarine can use GPS data to calculate its own position under water.
While electromagnetic data transmission only works up to 10 m or, in the best case, up to 300 m underwater distance, acoustic underwater telephony ( Gertrude ) from NATO now extends up to 10 km and can perhaps be further developed to a range of up to 100 km. Information via water- borne noise can also be exchanged in the form of Morse messages, which can increase the range with a lower information data rate. With civil submersibles, it is often advisable to use a cable connection up to a robotic satellite or to a supply ship, for example for electrical telephony. Bathyspheres and underwater platforms hang on a steel cable, which can also be accompanied by lines for energy, information and breathing air.
Ballistic missile bays in a submarine hull
Torpedoes are the most popular weapon used by military submarines. They are ejected from the fuselage via torpedo tubes and driven by a screw drive , and recently also by a water jet or a rocket engine leading to supercavitation . Modern torpedoes are usually remotely guided via a wire from the submarines firing them, but can also recognize targets independently. The torpedo rooms in which the torpedoes and other weapons are stored are usually located in the bow of the submarine. In more recent developments, for example the US Los Angeles class , however, the weapons were more likely to be amidships and the torpedo tubes pointed forward; In this way, a more powerful active sonar could be accommodated in the bow. Torpedo tubes in the stern of a submarine were still common until after the Second World War, but are no longer used today because they are not required for remotely steerable or autonomously targeting torpedoes.
Missiles can also be launched from the torpedo tubes of modern submarines . The most common principle here is to stow a missile, which can also be launched from surface ships, in a cylindrical container. This container leaves the submarine in the same way as a torpedo and penetrates the surface of the water; then he releases the missile. Such missiles are mainly used against ships.
Cruise missiles against land targets can also be launched from torpedo tubes. However, they are mostly fired from vertical launch shafts in order not to have to reduce the number of torpedoes carried. Submarine types specialized in the use of anti-ship guided missiles are generally classified with the abbreviations SSG and SSGN . In addition to the vertical starters mentioned, other starting methods were also used; The US-American USS Halibut was equipped with a launch pad on the foredeck, while on the Soviet classes Juliett and Echo the missiles were housed in launch containers that could be set up at an angle of 20 °. Contrary to modern designs, these early missile submarines all had to show up to fire the weapons.
Ballistic missiles ( submarine-launched ballistic missiles , SLBM) are launched from vertical shafts. They have a much larger diameter than torpedoes and should leave the water as quickly as possible. Most modern submarines with ballistic missiles (classification SSBN or SSB ) are equipped with a number of missile silos that are located amidships behind the tower. Exceptions are the Russian Typhoon class , in which the tower is at the end of the fuselage and the rockets in front, as well as the older, now decommissioned golf and hotel classes , where the rockets were housed in the tower. After the first ballistic missiles that could be fired from submarines were classified as medium-range missiles ( e.g. UGM-27 Polaris ), more modern missiles such as the Trident now have the range of ICBMs . Short-range missiles of the Scud type with a range of 150 km were only used as ballistic missiles on the older golf and hotel class submarines mentioned . Submarine launched ballistic missiles are mostly nuclear- equipped and are as in the theory of nuclear war second-strike weapons are used.
In contrast to earlier times, when submarines were armed with deck-mounted guns , modern submarines have little or no surface armament. Since submarines operate exclusively below the surface of the water these days, such armament is simply not needed. In addition, deck guns were removed from submarines towards the end of the Second World War in order to reduce hydrodynamic drag and increase underwater speed. However, the fact that submarines are almost unable to defend themselves against anti- submarine helicopters and planes calls for the development of anti-aircraft weapons that can be deployed from submerged submarines. There are only various shoulder-based anti-aircraft missile launchers similar to the well-known FIM-92 Stinger that are fired from the turret. For example, the Russian Sierra class is equipped with launchers for missiles of the 9K32 Strela-2MF or 9K34 Strela-3 types . The German Navy is currently developing the IDAS system for the 212 A submarine, an anti-aircraft weapon that can also be ejected from a torpedo tube by a submerged submarine and fired at a target above the surface of the water.
- Rescue submarine : Small, transportable and largely self-sufficient submarines that dock on the exit of the damaged submarine and evacuate it. Predecessors were special diving bells. Divers or tank diving equipment and underwater robots support the mission.
- Lifebuoy : It rises from the wreck, marks the scene of the accident and enables lifting equipment to be anchored via the buoy rope.
- Lifebuoy : A larger lifebuoy that can accommodate the crew. After the ascent it serves as a life raft.
- Diving rescuers : The mixture of breathing apparatus and life jacket enables emergency ascent after passing an exit lock or an exit collar (which makes it necessary to flood the submarine)(often the only escape route for small submarines).
- Other rescue measures: In the event of water ingress, watertight bulkheads limit water ingress. Emergency blow out of the diving cells and a dynamic emergency ascent to the surface may still be possible.
- Resus bottles: The hydrazine gas generators are modular, identical systems. In response to an electrical impulse, they generate the working gas required to blow out the immersion cells by catalytic decomposition of the hydrazine. The starting device of the "Resus" systems can be operated manually or fully automatically depending on a certain diving depth.
Submarines of the German Navy
The German Navy as an armed force the Bundeswehr has only submarines with diesel and fuel cell powered, but not on nuclear submarines. Since the tasks of the German Navy in the NATO alliance were initially set to pure coastal surveillance and only the "shallow" Baltic Sea and the North Sea were considered as operational fields, very small, quiet submarines not designed for great depths were particularly relevant. Therefore, during the time of the East-West conflict, the then 24 submarines of the then German Navy played an important role in the defense of the West German and Danish Baltic coasts against amphibious landings by the Warsaw Pact navies . There was also an international restriction that Germany was only allowed to have submarines (diving boats) up to a maximum of 500 tons of water displacement. With the changed political circumstances, however, the tasks of the German Navy have also changed. Nevertheless, nuclear submarines have so far been dispensed with in favor of the further development of conventional submarines. The new class 212 A fuel cell powered boats are primarily used to combat other submarines and for unnoticed reconnaissance and operate worldwide as required. Furthermore, up to June 2010, class 206A submarines were in service, their operational area stretching from the North and Baltic Seas to the Mediterranean. The commanders of the German submarines have the ranks of captainleutnant , corvette captain or frigate captain .
In addition to military use, there are civilian tasks for submarines.
- Deep-sea submarines or bathyscaphe are used for research purposes and can dive much deeper than military submarines. Most of them are constructed around a spherical pressure hull, run on batteries and cannot move very quickly. Their depth control is often done by vertical screw drives. Building on the Bathysphere by William Beebe from the 1930s, the bathyscaphs FNRS-2 , FNRS-3 and Trieste were used in the 1950sand were able to set ever larger deep diving records. The valid to date was January 23, 1960 with the Trieste placed in the later named after her Triestetief in the Mariana Trench reached a depth of 10,910 m. In addition to these bathyscaphs, which were constructed solely for vertical journeys when used for oceanographic research at great depths, numerous smaller research submarines were also manufacturedfrom around 1960, which are designed for shallower diving depths. They can be moved horizontally and are therefore suitable for a variety of scientific and technical work.
Search submarines are often unmanned to track down and examine objects on the ocean floor. For example, the expeditions to the wrecks of the Titanic (with the Alvin ) or the Bismarck became famous . The US Navy's NR-1 was the only nuclear-powered research submarine .
- Tourist submarinesAuguste Piccard (PX-8) , which dived in 1964 on the occasion of the Swiss National Exhibition with up to 40 passengers in Lake Geneva .
- Unmanned submarines (including diving robots ) are primarily used for research and are usually equipped with cameras, often also with gripping arms. They can dive extremely deep and are much smaller than manned submarines because they do not have to carry any oxygen supplies or passengers.
There are also remote-controlled submarine models that are built by model builders or sold as toys. Their diving depth is a few meters at most.
- Commercial submarines were only used in the two world wars to circumvent enemy sea blockades, to trade with neutral states and to procure essential warfare goods.
- Smuggling submarines :Submarines similar to semi-submersible ships(so-called self-propelled semi-submersibles / SPSS) are used to smuggle drugs. Since 2006 a large number of these boats have been built in the jungles of Colombia , which are between 12 and 25 m long and can transport up to 15 tons of goods or five people. They are mostly abandoned and sunk at their destination. In the GDR there were attempts to build miniature submarines for people to escape from the GDR , but these attempts wereexposedby the Stasi .
Other civil tasks :
- Rescue: Rescue or rescue of crashed submarine crews plays a role especially in the military field. After the loss of the submarines USS Thresher and Scorpion , the US Navy developed the so-called Deep Submergence Rescue Vehicle (DSRV). The USSR and Russian Federation ( Pris class ), Great Britain ( LR-5 ) and Sweden ( URF ) also have such vehicles in service, along with Italy, Japan, Korea, Australia and China.
- Repair / maintenance: Repair or maintenance of certain objects under water such as pipelines , drilling rigs , underwater stations or cables are often carried out by special repair submarines, which have the necessary devices or tools such as gripping arms, welding devices, wrenches etc. have. Diving robots are often used for this.
- Manned torpedo
- Group listening device
- Crazy Ivan
- Net deflector
- Peenemünde submarine museum
- Submarine bunker
- Submarine flotilla
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- formula for the chemical process of hydrogen production: CaH 2 + 2 H 2 O = Ca (OH) 2 + 2 H 2
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