Submarines Essay, Research Paper
Wouldn?t it be fun to ride a torpedo, or drive a nuclear reactor around underwater? In this research paper I am going to illustrate the ingenius submarine. The submarine is one of the most important strategic and tactical weapons systems of the 20th Century, and this importance will increase in the 21st Century. The tiny, leaking, creaking, and unsafe submarine boats of the 1890?s, displacing under two hundred tons and carrying a handful of men and a few torpedoes have grown into massive, sophisticated and deadly weapons systems. These displacing as much as 26,000 tons, carrying a crew of over a hundred and armed with missiles which can destroy large areas of the world. Every day hundreds of submarines are patrolling the oceans of the world. Many of them are on routine training, but some are armed with strategic missiles and for them every patrol is as fully functional as if they were at war. The surface of the ocean is hostile enough on occasion, but the depths are always hostile to man. Yet, for many centuries man has dreamed of penetrating the depths of the oceans and now this dream has become possible.A submarine is a ship that travels underwater. Most submarines are designed for use in war – to attack enemy ships or to fire missiles at enemy countries. These submarines range in length from about 200 feet to more than 550 feet. Their rounded hulls are about 30 feet in diameter. More than 150 crew members can live and work aboard such warships. At war a submarines will attack from beneath the surface of the water. A submarine needs to remain underwater to be effective. Early submarines did not stay submerged for long periods, because they had to surface often to get air for their engines and crews. Today?s nuclear submarines can stay underwater for several months at a time. A submarines long, cigar shaped body enables it to move swiftly while underwater. A pressure hull, made of high strength steel or titanium surrounds the ship and prevents it from being crushed by the pressure of the water around it. Built into the bow and stern of the pressure hull are tanks that, when filled with water, give the submarine ballast (weight) for diving. Submarines that are not built in the United States usually have a second, outer hull. The space between the hulls is used to store ballast tanks and equipment that does not need protection from water pressure. A tall, thin structure called the sail rises from the middle of a submarine?s deck. The sail stands about 20 feet high. It holds the periscopes and the radar and radio antennas. The top of the sail also serves as the bridge, from which the captain directs the submarine when on surface. Steel fins called diving planes stick out from both sides of the sail or bow and from the stern. These diving planes guide the ship to different depths. One or two propellers in the stern drive the submarine, also rudders above and below the propellers steer the craft. The earliest inventors had no other way but manpower to propel their submarines. Initially, this involved oars, then came propellers turned by hand, either by a single person, as in David Bushnell?s Turtle?. Or by several people turning a crank, as in a Confederate Hunley and the German Brandtaucher (meaning “Incendiary Diver”) in the mid-19th Century compressed-air was used as were electrical accumulators, both were of limited endurance and required the submarine to return to the port to recharge, which was tactically unacceptable. There were also a number of attempts to harness steam, not only for surface propulsion, but also to provide power when submerged, using stored energy devises, but none worked satisfactorily.Eventually it was realized that the solution was to combine the efficiency of the batteries for underwater propulsion and some form of power which could be used on the surface, both to propel the submarine and recharge its batteries. Steam was used tried several navies but it had numerous disadvantages. The steam plant made the interior of the submarine very hot and humid, and the furnace had to be cooled and damped down before submerging. Furthermore the system required funnels to get rid of the smoke. These needed vents to the outside, which, in turn, had to be closed by watertight valves, which were always a source of vulnerability. The gas engine was the obvious replacement for steam, and was introduced in 1904. This may have solved the problems with the vents, but equally introduced the hazards of fire and explosion, which led to a number of losses and deaths. Then the diesel came along, (1910 to 1920) it answered some of the problems and was much safer to use. However when they were at certain critical speeds, the vibration from the engine became so bad that it made its self-inoperable. As technology grew, so did the efficiency of the diesel engines. Air- independent propulsion systems were created. Soon following was research on nuclear propulsion. The outcome was two trial submarines, Explorer and Excaliber, whose propulsion system proved to be very hazardous in service. The research was discontinued. The apparent cheap alternative to nuclear propulsion had proved to be dangerous.The matter rested there for some years, with some talk of using fuel cells and other exotic systems, but with little serious action. However, there was a resurgence of interest in the 1980?s as new technology appeared to offer workable systems. Most major navies, with the exception of the U.S. Navy, now claimed to be working AIP (Air-Independent-Propulsion) technology and least and at least three submarines have carried out tests of working systems. Many if not all nuclear submarines have this technology as of now (1999).Now a great majority of modern nuclear-propelled submarines use pressurized- water reactors (PWR). In these systems, water acts as both a coolant and moderator, a tried and tested technique which has proved very reliable in the West, although a little less in the Soviet Navy. In such a system water travels through a primary circuit, passing several times through a nuclear reactor and thence to a steam generator (heat exchange). The water in the primary circuit has to be keep at a pressure point to prevent it from boiling and turning to steam, which is achieved by a pressurizer. Steam at the top of the pressurizer is used to compensate for changes in coolant volume as the reactor inlet and outlet temperatures vary. The heat energy is transferred in the steam generator from the pressurized water in the primary circuit to unpressurized water in the secondary circuit, which then becomes steam and drives the turbine. Having driven the turbine it passes into a series of condensers, becoming water once again and returning in liquid form to the steam generator to continue the cycle. PWR condensers use the seawater as a heat sink and require a constant throughput provided either by the forward motion of the submarine, or, at slow speeds, by the use of pumps. The operation of a PWR installation requires considerable auxiliary power, mainly to operate the circulation pumps in the primary circuit and the electrical heater elements in the pressurizer. The system can be to use natural circulation resulting from the thermal gradients set up from the nuclear reaction, but at higher levels pumps still have to be switched in. Some systems, in an effort to minimize noise and vibration, use several pumps, which can be selectively activated, according to the power level. Whatever the system, however, all these pumps create low-level noise, which can be detected by suitable sensors.Various alternative coolants have been tried. USS Seawolf, launched in 1955, was fitted with a S2G liquid sodium-cooled reactor, which effected a much more efficient heat transfer, but was very troublesome in service. There were two particular problems, the more stubborn sodium had to be kept at a liquid at all times, otherwise it returned to a solid and ruined the primary circuit pipes. The second was that of high-pressure steam leaks. After two years the S2G was changed for a S2Wa PWR, virtually identical to that installed in the Nautilus. The Soviet Alfa and Mike class SSN?s are both agreed to have liquid metal-cooled reactors, but it has been recently confirmed that they have a new type of smaller PWR. How a submarine dives is by flooding its ballast tank with water. The added weight causes the ship to move downward losing its positive buoyancy (ability to stay afloat), and it becomes neutrally buoyant. Then the submarines diving planes are tilted down and the craft dives smoothly down into the water. Most submarines can dive to a depth of over 100 feet in less than a minute. Most modern combat submarines operate at a depth of about 1,300 feet or less. If they were to dive deeper, the water pressure would cause damage to them. Once underwater a submarine travels somewhat as an airplane moves through the air. The diving planes angle up and down to raise or lower the ship. Two crewmen sit like at aircraft controls. They push the controls forward to make the submarine descend or pull back, causing the craft to rise. Turning the controls to the right or left moves the rudder and steers the ship. A submarine is bought to the surface in one of two ways. Water is blown out the ballast tanks by compressed air, or the diving planes are tilted so the submarine angles up. On the surface of the water, a submarine pre-forms much like any other ship. A submarine can cruise at about 20 knots on the surface. However, modern submarines spend very little time above water.The machinery of a submarine is extremely complicated. All of the continuing submarines, of the U.S. Navy, after nine years must have a 12-month refit of the entire craft. After a usual 70-day patrol, they go through a 25-day short refit. Now a vast majority of the submarines navigational and propulsion systems are all controlled by computers. The weapons machinery is also a large part of the submarine; in fact on most submarines 3/5 is weapons systems. The weapon that made the submarine an effective weapon of war was the torpedo, which is really a self-contained submarine. The earliest torpedo device was the spar-torpedo, which was long, wooden spar with an explosive charge which detonated on contact with an enemy, an dangerous device. This defect was solved when Whitehead created an automotive torpedo. Early torpedoes had a diameter of 14 inches, but this was quickly increased to 17 inches. The 21-inch was introduced just before World War I, and it became the international standard for the next eighty years. Any torpedo consists of three elements: a warhead, a propulsion system and a guidance/control system. The original explosive used was wet guncotton, but this was replaced with TNT in the World Wars, then TNT was replaced with Torpex. Further additives in the post-war years have further increased explosive more stable over a longer period. Torpedo propulsion systems originally used compressed-air, while later steam was favored. Both systems left a stream of exhaust bubbles, which could be spotted in broad daylight by a watchkeeper on the target ship. Soon can an electric torpedo, which was researched by the Germans, followed by the British and Americans. Other attempt have been made in various countries to use hydrogen-peroxide as a propellant, but this substance is notoriously difficult to handle, and it has caused explosions on at least one submarine in the 1950?s, but the Swedish continue to use it. Control, for torpedoes, originally meant ruling on a set course and a set depth. Indeed, the famous Whitehead torpedo was the device that maintained it at a precise depth. The achievement of consistently reliable control has always been difficult and one of the problems with the U.S. Navy?s Mark XIV torpedo. In the early years of the World War II was that it frequently ran deeper than had been set, thereby passing well under the targets. During the war both passive and active homing heads have been developed. An active head transmitted sonar pulses, which, when reflected by a target, were detected and used to home the torpedo onto the target. Passive heads were homed on the acoustic signals transmitted by a target. Most modern torpedoes have complicated guidance systems including an active and passive sonar transducer. The transducer changes automatically to the active mode once the target indicates that it has become aware of the attack. Sonar information from the torpedo?s sensors is transmitted back to the submarine by wires and guidance commands to the torpedo are passed forward by the same means. Warhead design is also becoming more important as submarines hulls become ever stronger. Various navies are now examining the feasibility of larger diameter torpedoes. The U.S. Navy will soon start sea trails of a 30-inch torpedo. In general terms, however, the capabilities of modern torpedoes lag behind those of the sonars that support them. They are slow, lack range, and are noisy. Torpedoes have proved to be unreliable and sometimes wayward weapons over the years. Submariners of all nations have experienced problems with them. A particular tragic example is that of the USS Tang, one of the most successful of all U.S. submarines in the World War I. During an attack on a Japanese convoy she fired her last torpedo, it veered in a half circle and hit the Tang herself, causing immediate and fatal damage. The bridge party of ten was throw off into the water, while the ship sank with the rest of the crew. The most common method of launching a torpedo is by use of fixed tubes, mounted within the pressure-hull. The earliest submarines had all such tubes mounted in the bows, but in 1907 a Russian submarine was launched with tubes in the stern. From then on most submarines have stern tubes, whose main tactical purpose is to fire torpedoes at pursuing ASW (anti-submarine warfare) surface warships. Such an installation became impossible when the use of single propellers was introduced in the 1960?s and today very few submarines have such an installation. The tubes are angled to fire forward about 20? from the hull. Some submarines have a positive discharge weapon ejection system; were the weapon is ejected by pressurized water by the air-turbine pump, which is controlled by a programmable firing valve. The first gun to be installed on a submarine was the ?dynamite gun? mounted in the early U.S. Navy Holland class. For some years submarines were armed only with torpedoes, but in 1911 the Royal Navy launched a submarine with one 12-inch powder gun. The gun was on a complicated disappearing mount, which was soon realized that a fixed mount was cheaper, lighter, and easier to maintain. Once World War I had started, and the value of the gun in saving the use of valuable torpedoes against merchant ships was demonstrated, virtually all submarines were fitted with one. After the war the Germans were the first to realize that the gun and its mount created a great deal of hydrodynamic resistance and that, in any case, radar and the use of the submarine on the surface. So they got rid of there guns, as follows several other navies. By the late 1950?s there were virtually no deck guns left. Although curiously, the Peruvian Navy still remains a gun on its Dos de Mayo class submarine in the 1990?s.Air defense has always been a particular threat to submarines. Initially, the response was to mount anti-aircraft cannons or machine-guns to provide defense while on the surface. However, time spent on the surface became increasingly hazardous, and the entry into service of the snorkel meant those submarines stayed below, even when running their diesels. So, the need for air defense weapons reduced, although there was a brief rekindling of interest when the British developed a device called the SLAM (Submarine-Launched Air-Defense) in the 1960?s. However, this weapon presupposed that the submarine was traveling at periscope depth, which still made it vulnerable. The SLAM never entered the service. Even though the aircraft threat persists, especially as a submerged submarine often has no idea that an aircraft is even in the area, let alone tracking it, until an ASW is launched. The Euromissile Consortium is now developing the Polyhem missile, which can be launched through the torpedo tube of a deeply submerged submarine. It ascends to the surface in a capsule before launching itself at the attacking aircraft. The first SLCM (Submarine-Launched Cruise Missile) was the Regulus 1, which consisted of a small, unmanned, swept-wing aircraft missile, powered by a turbojet, with RATO (Rocket-Assisted Take-Off). Regulus 1, which could only be launched from the surface, was only capable of attacking large area targets and required mid-range course guidance from radar picket submarines. The first purpose-built SLCM?s carriers were the nuclear-powered Echo 1. However, these Soviet missiles were not, as was the U.S. Navy?s Regulus, intended for anti-city operations, but instead for anti-ship missions against U.S. aircraft-carrier task groups. Following the U.S. development of the Tomahawk missile system the USSR has developed a strategic SLCM of its own. The first nation to consider firing ballistic missiles (an unguided missile that travels at its target after its launch) from underwater was Germany. Who in 1944 had a design on the drawing boards for a submerged towing-body which would have transported and launched V-2 rockets, possibly for use against New York. At the end of World War II, both the USA and the USSR worked on the V-2s they captured, helped, in both cases, by German scientist. The first ballistic missile submarines to enter the four boats of the Zulu V class, which had been converted to take two SLBM?s mounted vertically in the fin. The US Navy meanwhile briefly considered a 8,500 ton submarine armed with six liquid-fuel Jupiter-S missiles, but then settled on the more ambitious, solid-fueled Polaris project. Few weapons in history have combined more dramatic technology innovations that this SLBM, which was designed by Admiral WF Raborn, USN, and a team from Lockheed. When the Polaris entered the service in 1960 it changed the nature of strategic confrontation. Since then the US SLBM?s have been steadily developed from Polaris through Posiedon to Trident, with increases in range and reliability in each model. Warheads, too, have had great advances in maneuverability, and power. The Soviet Navy meanwhile persisted with liquid-fuelled missiles, but nevertheless developed some very effective missiles, whose great range enabled them to withdraw their SSBN?s into the one of the two, Sea of Okhotsk, or the Arctic Ocean. Soviet SSBN?s progressed through the Yankee class, the Delta class, and thence to the largest submarine ever built, the Typhoon class, armed with 20 nuclear missiles. Having seen the strategic power available in the SLBM/SSBN combination, first the UK, then France and China developed their own fleets. The only other nation, which looks as though it might soon join, is India.Attack submarines of the U.S. Navy go on patrol for two or three months, although they frequently stop during the trip. SLBM submarines usually stay on patrol for about 60 days and spend almost the entire time underwater. The sailors on attack submarines and ballistic missile submarines have many comforts during their cruise. For example, large air-conditioned units keep the temperature and humidity at comfortable levels. Libraries, motion pictures, and game rooms help ease the monotony of life beneath the sea. On most submarines, every member of the crew works a daily four-hour shift called a watch. At the end of his watch, a crewman is relieved and goes off duty for eight hours. He may have to do some maintenance work on the ship but is mostly free to relax or study until he returns to his station. The work assignments vary so that all the crewmen have days off. A submarine returns to the port at the end of its cruise. It receives any needed repairs and takes on additional supplies. A ballistic missile submarine also changes crews. Each ballistic missile submarine in the U.S. Navy has two crews, the blue crew, and the gold crew. After one crew completes a patrol, it is replaced by the other. The on coming crew takes the submarine on another mission. The men return to shore, and go on leave and then receive additional training. After the crew of an attack submarine completes its patrol, it spends six months in port and in local operations.There are hundreds of different types of submarines in the world today, and a majority of them are a war vessel. There are three general types of submarines, navy, research, and recreational submarines. The U.S. Navy has eight classes of submarines. These are the Holland, L., Argonaut, Gato, Albacore, Nautilus, Los Angeles, Ohio class submarines. The minelayers were an idea of a specialized submarine, which originated with the Russians, the Krab. She was followed by the Germans with their UC-1 class in 1915. Then most navies, following one, of two basic concepts built small numbers of minelayers. In one the mines were placed on a horizontal conveyor, located under the upper casting, which moved the mines towards the stern where they were dropped through two holes clear of the propellers. This was the system pioneered in Krab and the American and British used similar systems. The various systems worked quite well, but the complicated mechanical devices, plus the mines, placed a lot of weight high on the submarine, which interfered with their stability. The second concept, which was pioneered by the Germans, quite different and consisted of vertical tubes holding one, two or three mines and from which the mines were dropped. In some installations the tubes were mounted in the hull and in others, they were in the ballast tanks. The loss among specialized was quite high. Eventually the requirement for such a type faded out during World War II because mines were developed which could be launched from standard torpedo tubes. However, two types of “strap-on” mine-laying “girdles”, appeared in the late 1980?s, with which additional mine laying capability without interfering with the number of torpedoes being carried. One system is being produced in Germany, the other in Sweden. Submarines have been used as transports on numerous occasions and, at its most basic, men or stores are simply fitted in where feasible without any modifications to the submarine. Numerous missions have been accomplished in such a way. The Germans used submarines as supply transports during the invasion of Norway in 1940. There load simply consisted of one 88mm anti-aircraft gun, 774 rounds of 88mm ammunition, eight 250kg bombs, 60m? of aircraft fuel, and 1,800kg of lubricating oil. A number of Japanese combat submarines visited Europe during the war and all carried what supplies they could in both directions. The British also used submarines to run supplies to Malta in 1942, and to the Aegean islands in 1943. During the World War I the Allied blockade of Germany began to bite very quickly and one proposed method of breaking it was by construction of a purpose-built transport submarines of the Deutschland class. Deutschland herself made one return trip to the USA entered the war there was no further use for the class in a commercial role and the survivors were converted into cruisers as the U-151 class. Most large submarines can carry some 50 tons of supplies. One unusual device called the unkato, a streamlined cylindrical canister capable of carrying 337 tons of cargo. The unkato was towed behind a submerged submarine to its destination, where both submarine and cylinder surfaced and the latter was towed to shore by local boats. Only a small number of unkato missions were successful. The Germans also tested a similar device. The IJN (Imperial Japanese Navy) also built twelve transport submarines, but eight were lost at war. Astonishingly, the Japanese Army built a number of its own transport submarines. Twenty-six were built of two types, the Yu1 and Yu1001 classes, the great majority of which were sunk by U.S. forces. During the war the U.S. Navy also used a number of combat submarines on transport missions, particularly to resupply isolated island garrisons and on clandestine missions in support of guerillas in the Philippines. After the war three fleet submarines were converted to transport. These carried 111 troops, 85 tons of supplies, a tracked amphibious vehicle, a jeep, and eight 10-man dinghies in support of amphibious landings on hostile beaches. This involved considerable internal modifications and a large watertight cylindrical hangar was installed on the after casing. These submarines received the classification of APSS. It is believed that the Soviet Special Forces have operational attack submarines that may transport their Spetnaz troops. Although other navies can carry small numbers of Special Forces in their attack submarines, none is known to have been converted, to carry any such large numbers.In the latter days of the Pacific, surface warships were used as radar pickets to help guide bombers towards their targets in Japan, but there losses were heavy, especially to the Japanese kamikaze aircraft. Consequently, afterwards the U.S. Navy developed the idea of submarine pickets, designated SSR. Radar sets were installed inside the submarines, where the equipment and operators took up a great deal of space. The antennas were mounted on the upper casing or on the fin. The radar pickets were used to control friendly aircraft, and some were able to provide mid-course guidance to submarine launched cruise missiles. There were two major weaknesses. First, in order to operate their antennas the submarine had to remain close to the surface, which made them almost as vulnerable as the ships they were replacing. Secondly, except for the nuclear-powered, they did not have the speed to operate with a carrier task force. When carrier-based airborne early warning aircraft entered the surface in the late 1950?s the project was dropped and the boats were either converted to other duties or scrapped. Several navies have from time to time disposed of elderly submarines ready for scrapping by serving as targets. Also, submarines are frequently used as targets for ASW exercises in which sensors are used, but which stop short of actually firing a weapon. Following World War II there was a brief interest in the use of submarines as targets for homing torpedoes with dummy warheads, in order to carry out trials and to practice operational crews. In the U.S. Navy, the Manta was converted in 1949, being given considerable extra protection for the role, which only lasted until 1953. In the Royal Navy one submarine HMS Scotsman was given a similar conversion and used as a target for some years. The Soviet Navy actually built a specialized class of target submarines in the late 1960?s, which are still in service. The Bravo class is fitted with considerable protection. Four were built.Only two navies have ever used “command-and-control” submarines. The IJN actually though of submarines fighting in “fleets” under the command of an admiral afloat with his forces. As a result, the admiral needed flagships in order to command their forces and these were provided in the A1 Type. This submarine had an additional accommodation for the admiral and his staff, together with special radio equipment. Three were completed, of which two were sunk by US forces and the third sank as an operational loss in1944. The Soviet Navy fitted three elderly Golf-1 class submarines with an extra communications in the 1970?s. These may have been intended for a special task, but the submarines have now been deleted, and the role dropped. The German U-boat commander in World War II, Admiral Donitz, often organized his submarines into “wolf-packs” and he considered the idea that these should be commanded by special flagship U-boats. Not only would this have meant the pack commander transmitting a lot of radio signals (which would be intercepted), but also meant that the flagship would have to remain separate from the immediate battle in order to exercise command properly. In such a case it seemed better to exercise command from ashore and the idea of a flagship was dropped, although the senior captain of the “pack” was often given certain local responsibilities. One submarine was briefly considered for what might be termed the ultimate command-control role. When the U.S. Navy?s nuclear-propelled radar picket Triton became redundant in its radar picket role, plans were prepared to convert it into a submerged Alternative National Command Post (ANCP) for the President and his staff to use during a nuclear war. The project never became to be. The sophisticated and deadly submarine has not seen the last of its days. It is already one of the most deadly weapons in the world. The submarine may rise to be one of the most strategic weapons in the world, since ? the earth is water. The submarine ships will increase with technology, and skill. And the great history of those who persevered to meet man?s dream of navigating underwater will remain.”Again the question arises as to what a submarine can do against a merchant ship when she has found her? She cannot capture the merchant ship; she has no spare hands to put her prize crew on board, little or nothing would be gained by disabling her engine or propeller, she cannot convoy herself into harbor? there is nothing else the submarine can do except sink her to the capture?”