1.
United States Coast Guard
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The United States Coast Guard is a branch of the United States Armed Forces and one of the countrys seven uniformed services. This has happened twice, in 1917, during World War I, created by Congress on 4 August 1790 at the request of Alexander Hamilton as the Revenue Marine, it is the oldest continuous seagoing service of the United States. As Secretary of the Treasury, Hamilton headed the Revenue Marine, by the 1860s, the service was known as the U. S. Revenue Cutter Service and the term Revenue Marine gradually fell into disuse, the modern Coast Guard was formed by a merger of the Revenue Cutter Service and the U. S. Life-Saving Service on 28 January 1915, under the U. S. Department of the Treasury. As one of the five armed services, the Coast Guard has been involved in every U. S. war from 1790 to the Iraq War. As of 2014 the Coast Guard had over 36,000 men and women on duty,7,350 reservists,29,620 auxiliarists. In terms of size, the U. S. Coast Guard by itself is the worlds 12th largest naval force. Because of its authority, the Coast Guard can conduct military operations under the U. S. Department of Defense or directly for the President in accordance with Title 14 USC 1–3. The Coast Guards enduring roles are maritime safety, security, to carry out those roles, it has 11 statutory missions as defined in 6 U. S. C. §468, which include enforcing U. S. law in the worlds largest exclusive economic zone of 3.4 million square miles, the Coast Guards motto is the Latin phrase, Semper Paratus. In a 2005 article in Time magazine following Hurricane Katrina, the author wrote, the Coast Guards most valuable contribution to may be as a model of flexibility, and most of all, spirit. Wil Milam, a swimmer from Alaska told the magazine, In the Navy. Practicing for war, training for war, in the Coast Guard, it was, take care of our people and the mission will take care of itself. The Coast Guard carries out three basic roles, which are subdivided into eleven statutory missions. Both agencies maintain rescue coordination centers to coordinate this effort, and have responsibility for military and civilian search and rescue. The two services jointly provide instructor staff for the National Search and Rescue School that trains SAR mission planners and coordinators, previously located on Governors Island, New York, the school is now located at Coast Guard Training Center Yorktown at Yorktown, Virginia. The NRC also takes Maritime Suspicious Activity and Security Breach Reports, details on the NRC organization and specific responsibilities can be found in the National Oil and Hazardous Substances Pollution Contingency Plan. The Marine Information for Safety and Law Enforcement database system is managed and used by the Coast Guard for tracking pollution, the five uniformed services that make up the U. S
2.
Tucker-class destroyer
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The Tucker class of destroyers was a ship class of six ships designed by and built for the United States Navy shortly before the United States entered World War I. The Tucker class was the fourth of five classes of destroyers that were known as the thousand tonners, because they were the first U. S. destroyers over 1,000 long tons displacement. The design of what became the Tucker class was the result of compromises between the General Board of the United States Navy and the U. S. Navys Bureau of Construction and Repair. S. Input from Construction and Repair resulted in a design that was a development of the OBrien class, which itself was similar to the first of the thousand tonners. Navy between July 1915 and May 1916, the ships had a median displacement of 1,060 long tons, were just over 315 feet in length, and had a beam of about 30 feet. All of the ships were designed for a speed of 29.5 knots. As built, they were armed with four 4-inch guns and had four twin 21-inch torpedo tubes with a load of eight torpedoes, but all were later equipped with depth charges. All six ships operated in the Atlantic or Caribbean until the U. S. entrance into World War I in April 1917, when all six were sent overseas to Queenstown, Ireland, for convoy escort duties. Several of the rescued passengers and crew from ships sunk by U-boats. All five surviving members of the class had returned to the United States by early 1919, between 1924 and 1926, four of the five were commissioned into the United States Coast Guard to help enforce Prohibition as a part of the Rum Patrol. They were returned to U. S. Navy custody between 1934 and 1936, and had all sold for scrapping by 1936. In September 1912, the General Board of the United States Navy asked the Navys Bureau of Construction, C&R came back with a design for a 385-foot long,2, 160-long-ton displacement, triple-screw super-destroyer requiring 40,000 shaft horsepower to make the design speed of 35 knots. The C&R design was similar to, but larger than the unique British destroyer HMS Swift of 1907, the General Board, whose main concern was the integrated operation of the United States battle fleet, pushed for the design to provide more scouting capabilities for fleet operations. But the high cost of the design—$1,900,000 for hull and machinery vs.5 knots, the C&R design for the Tucker class, DD-57 through DD-62, was approved by the Secretary of the Navy in December 1912, and authorized by Congress in 1913. As built, the Tucker-class ships were 315 feet 3 inches in length, were between 29 feet 9 inches and 30 feet 6 inches abeam, and had a draft of 9 feet 4 inches. The hull shape featured the high forecastle typical of U. S. destroyer classes since the 1908–09 Smith class. The ships displaced between 1,060 and 1,150 long tons with a median of 1,060 long tons. The ships were equipped with two shafts and two Curtis steam turbines fed by four Yarrow boilers, providing a minimum of 17,000 shaft horsepower to achieve the design speed of 29.5 knots
3.
Destroyer
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Before World War II, destroyers were light vessels with little endurance for unattended ocean operations, typically a number of destroyers and a single destroyer tender operated together. After the war, the advent of the missile allowed destroyers to take on the surface combatant roles previously filled by battleships. This resulted in larger and more powerful guided missile destroyers more capable of independent operation, the emergence and development of the destroyer was related to the invention of the self-propelled torpedo in the 1860s. A navy now had the potential to destroy an enemy battle fleet using steam launches to launch torpedoes. Fast boats armed with torpedoes were built and called torpedo boats, the first seagoing vessel designed to fire the self-propelled Whitehead torpedo was the 33-ton HMS Lightning in 1876. She was armed with two drop collars to launch these weapons, these were replaced in 1879 by a torpedo tube in the bow. By the 1880s, the type had evolved into small ships of 50–100 tons, in response to this new threat, more heavily gunned picket boats called catchers were built which were used to escort the battle fleet at sea. The anti-torpedo boat origin of this type of ship is retained in its name in other languages, including French, Italian, Portuguese, Czech, Greek, Dutch and, up until the Second World War, Polish. At that time, and even into World War I, the function of destroyers was to protect their own battle fleet from enemy torpedo attacks. The task of escorting merchant convoys was still in the future, an important development came with the construction of HMS Swift in 1884, later redesignated TB81. This was a torpedo boat with four 47 mm quick-firing guns. At 23.75 knots, while still not fast enough to engage torpedo boats reliably. Another forerunner of the torpedo boat destroyer was the Japanese torpedo boat Kotaka, designed to Japanese specifications and ordered from the London Yarrow shipyards in 1885, she was transported in parts to Japan, where she was assembled and launched in 1887. The 165-foot long vessel was armed with four 1-pounder quick-firing guns and six torpedo tubes, reached 19 knots, in her trials in 1889, Kotaka demonstrated that she could exceed the role of coastal defense, and was capable of accompanying larger warships on the high seas. The Yarrow shipyards, builder of the parts for the Kotaka, the first vessel designed for the explicit purpose of hunting and destroying torpedo boats was the torpedo gunboat. Essentially very small cruisers, torpedo gunboats were equipped with torpedo tubes, by the end of the 1890s torpedo gunboats were made obsolete by their more successful contemporaries, the torpedo boat destroyers, which were much faster. The first example of this was HMS Rattlesnake, designed by Nathaniel Barnaby in 1885, the gunboat was armed with torpedoes and designed for hunting and destroying smaller torpedo boats. Exactly 200 feet long and 23 feet in beam, she displaced 550 tons, built of steel, Rattlesnake was un-armoured with the exception of a 3⁄4-inch protective deck
4.
Yarrow boiler
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Yarrow boilers are an important class of high-pressure water-tube boilers. They were developed by Yarrow & Co, shipbuilders and Engineers and were widely used on ships, particularly warships. The Yarrow boiler design is characteristic of the boiler, two banks of straight water-tubes are arranged in a triangular row with a single furnace between them. A single steam drum is mounted at the top between them, with water drums at the base of each bank. Circulation, both upwards and downwards, occurs within this same tube bank, the Yarrows distinctive features were the use of straight tubes and also circulation in both directions taking place entirely within the tube bank, rather than using external downcomers. Early use of the water-tube boiler within the Royal Navy was controversial at times and these first boilers, such as the Belleville and Niclausse, were large-tube designs, with simple straight tubes of around 4 diameter, at a shallow angle to the horizontal. These tubes were jointed into cast iron headers and gave much trouble with leakage at these joints, at the time, an assumption was that thermal expansion in these straight tubes was straining the joints. These boilers were also large, and although fitted to many pre-dreadnought battleships, could not be fitted to the torpedo boats. To provide a lighter boiler for smaller vessels, the Express types were developed and these used smaller water-tubes of around 2 diameter, giving a greater ratio of heating area to volume. Most of these were of the pattern, particularly of the Du Temple. This gave a more vertical arrangement of the water-tubes, thus encouraging thermosyphon circulation in these narrow tubes. The previous problems of tube expansion were still a concern and so the tubes were either curved, or even convoluted into hairpins and S shapes. Alfred Yarrow developed his boiler as a response to others that had already developed water-tube boilers and this was a long process based on theoretical experiment rather than evolution of practical boilers. Work began in 1877 and the first commercial boiler was not supplied until 10 years later, despite this long gestation, the boilers origins appear to have been most direct. Already expressed two of the three basic design principles. Early water-tube designers had been concerned with the expansion of the tubes when heated. Efforts were made to them to expand freely, particularly so that those closest to the furnace might expand relatively more than those further away. Typically this was done by arranging the tubes in large looping curves and these had difficulties in manufacturing and required support in use
5.
Steam turbine
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A steam turbine is a device that extracts thermal energy from pressurized steam and uses it to do mechanical work on a rotating output shaft. Its modern manifestation was invented by Sir Charles Parsons in 1884, in 1551, Taqi al-Din in Ottoman Egypt described a steam turbine with the practical application of rotating a spit. Steam turbines were described by the Italian Giovanni Branca and John Wilkins in England. The devices described by Taqi al-Din and Wilkins are today known as steam jacks, in 1672 an impulse steam turbine driven car was designed by Ferdinand Verbiest. A more modern version of car was produced some time in the late 18th century by an unknown German mechanic. The modern steam turbine was invented in 1884 by Sir Charles Parsons, the invention of Parsons steam turbine made cheap and plentiful electricity possible and revolutionized marine transport and naval warfare. Parsons design was a reaction type and his patent was licensed and the turbine scaled-up shortly after by an American, George Westinghouse. The Parsons turbine also turned out to be easy to scale up. Parsons had the satisfaction of seeing his invention adopted for all major world power stations, a number of other variations of turbines have been developed that work effectively with steam. The de Laval turbine accelerated the steam to full speed before running it against a turbine blade, De Lavals impulse turbine is simpler, less expensive and does not need to be pressure-proof. It can operate with any pressure of steam, but is less efficient. He taught at the École des mines de Saint-Étienne for a decade until 1897, one of the founders of the modern theory of steam and gas turbines was Aurel Stodola, a Slovak physicist and engineer and professor at the Swiss Polytechnical Institute in Zurich. His work Die Dampfturbinen und ihre Aussichten als Wärmekraftmaschinen was published in Berlin in 1903, a further book Dampf und Gas-Turbinen was published in 1922. It was used in John Brown-engined merchant ships and warships, including liners, the present-day manufacturing industry for steam turbines is dominated by Chinese power equipment makers. Other manufacturers with minor market share include Bhel, Siemens, Alstom, GE, Doosan Škoda Power, Mitsubishi Heavy Industries, the consulting firm Frost & Sullivan projects that manufacturing of steam turbines will become more consolidated by 2020 as Chinese power manufacturers win increasing business outside of China. There are several classifications for modern steam turbines, Turbine blades are of two basic types, blades and nozzles. Blades move entirely due to the impact of steam on them and this results in a steam velocity drop and essentially no pressure drop as steam moves through the blades. A turbine composed of alternating with fixed nozzles is called an impulse turbine, Curtis turbine, Rateau turbine
6.
QF 1-pounder pom-pom
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The QF1 pounder, universally known as the pom-pom due to the sound of its discharge, was a 37 mm British autocannon, the first of its type in the world. It was used by several countries initially as an infantry gun, hiram Maxim originally designed the Pom-Pom in the late 1880s as an enlarged version of the Maxim machine gun. Early versions were sold under the Maxim-Nordenfelt label, whereas versions in British service were labelled Vickers, Sons and they are all effectively the same gun. The Belgian Army used the gun on a field carriage mounting. A version was produced in Germany for both Navy and Army, in World War I, it was used in Europe as an anti-aircraft gun as the Maxim Flak M14. Four guns were used mounted on carriages in the German campaign in South West Africa in 1915. The British government initially rejected the gun but other countries bought it, in the Second Boer War, the British found themselves being fired on with success by the Boers with their 37 mm Maxim-Nordenfelt versions with ammunition made in Germany. In response, Vickers-Maxim of Britain shipped either 57 or 50 guns out to the British Army in South Africa and these early Mk I versions were mounted on typical field gun type carriages. In World War I, it was used as an early anti-aircraft gun in the defence of Britain. 25 were employed in August 1914, and 50 in February 1916, a Mk II gun on a Naval pedestal mounting was the first to open fire in defence of London during the war. However, the shell was insufficient to damage the German Zeppelin airships sufficiently to bring them down. The Ministry of Munitions noted in 1922, The pom-poms were of little value. There was no shrapnel available for them, and the provided for them would not burst on aeroplane fabric. Were of no use except at a lower elevation than a Zeppelin attacking London was likely to keep. Hogg of No.2 AA Section in III Corps was the first anti-aircraft gunner to shoot down an aircraft, with 75 rounds on 23 September 1914 in France. The gun was mounted on aircraft as the lighter 1-pounder Mk III. As a light gun, it was quickly replaced by the larger QF 1½ pounder. The British are reported to have used some Common pointed shells in the Boer War
7.
Torpedo tube
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A torpedo tube is a cylinder shaped device for launching torpedoes. There are two types of torpedo tube, underwater tubes fitted to submarines and some surface ships. Thus a submarine torpedo tube operates on the principle of an airlock, the diagram on the right illustrates the operation of a submarine torpedo tube. The diagram is somewhat simplified but does show the working of a torpedo launch. A torpedo tube has a number of interlocks for safety reasons. For example, an interlock prevents the door and muzzle door from opening at the same time. The submarine torpedo launch sequence is, in simplified form, Open the breech door in the torpedo room, load the torpedo into the tube. Hook up the connection and the torpedo power cable. Shut and lock the breech door, turn on power to the torpedo. A minimum amount of time is required for torpedo warmup, fire control programs are uploaded to the torpedo. This may be manually or automatically, from sea or from tanks. The tube must be vented during this process to allow for complete filling, Open the equalizing valve to equalize pressure in the tube with ambient sea pressure. If the tube is set up for Impulse Mode the slide valve will open with the muzzle door, if Swim Out Mode is selected, the slide valve remains closed. The slide valve allows water from the pump to enter the tube. Modern torpedoes have a safety mechanism that prevents activation of the torpedo unless the torpedo senses the required amount of G-force, the power cable is severed at launch. However, if a wire is used, it remains connected through a drum of wire in the tube. Torpedo propulsion systems vary but electric torpedoes swim out of the tube on their own and are of a smaller diameter,21 weapons with fuel-burning engines usually start outside of the tube. Once outside the tube the torpedo begins its run toward the target as programmed by the control system
8.
World War I
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World War I, also known as the First World War, the Great War, or the War to End All Wars, was a global war originating in Europe that lasted from 28 July 1914 to 11 November 1918. More than 70 million military personnel, including 60 million Europeans, were mobilised in one of the largest wars in history and it was one of the deadliest conflicts in history, and paved the way for major political changes, including revolutions in many of the nations involved. The war drew in all the worlds great powers, assembled in two opposing alliances, the Allies versus the Central Powers of Germany and Austria-Hungary. These alliances were reorganised and expanded as more nations entered the war, Italy, Japan, the trigger for the war was the assassination of Archduke Franz Ferdinand of Austria, heir to the throne of Austria-Hungary, by Yugoslav nationalist Gavrilo Princip in Sarajevo on 28 June 1914. This set off a crisis when Austria-Hungary delivered an ultimatum to the Kingdom of Serbia. Within weeks, the powers were at war and the conflict soon spread around the world. On 25 July Russia began mobilisation and on 28 July, the Austro-Hungarians declared war on Serbia, Germany presented an ultimatum to Russia to demobilise, and when this was refused, declared war on Russia on 1 August. Germany then invaded neutral Belgium and Luxembourg before moving towards France, after the German march on Paris was halted, what became known as the Western Front settled into a battle of attrition, with a trench line that changed little until 1917. On the Eastern Front, the Russian army was successful against the Austro-Hungarians, in November 1914, the Ottoman Empire joined the Central Powers, opening fronts in the Caucasus, Mesopotamia and the Sinai. In 1915, Italy joined the Allies and Bulgaria joined the Central Powers, Romania joined the Allies in 1916, after a stunning German offensive along the Western Front in the spring of 1918, the Allies rallied and drove back the Germans in a series of successful offensives. By the end of the war or soon after, the German Empire, Russian Empire, Austro-Hungarian Empire, national borders were redrawn, with several independent nations restored or created, and Germanys colonies were parceled out among the victors. During the Paris Peace Conference of 1919, the Big Four imposed their terms in a series of treaties, the League of Nations was formed with the aim of preventing any repetition of such a conflict. This effort failed, and economic depression, renewed nationalism, weakened successor states, and feelings of humiliation eventually contributed to World War II. From the time of its start until the approach of World War II, at the time, it was also sometimes called the war to end war or the war to end all wars due to its then-unparalleled scale and devastation. In Canada, Macleans magazine in October 1914 wrote, Some wars name themselves, during the interwar period, the war was most often called the World War and the Great War in English-speaking countries. Will become the first world war in the sense of the word. These began in 1815, with the Holy Alliance between Prussia, Russia, and Austria, when Germany was united in 1871, Prussia became part of the new German nation. Soon after, in October 1873, German Chancellor Otto von Bismarck negotiated the League of the Three Emperors between the monarchs of Austria-Hungary, Russia and Germany
9.
O'Brien-class destroyer
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The OBrien class of destroyers was a class of six ships designed by and built for the United States Navy shortly before the United States entered World War I. The OBrien class was the third of five classes of destroyers that were known as the thousand tonners, the design of what became the OBrien class was the result of discussions between the General Board of the United States Navy and the U. S. Navys Bureau of Ordnance. What resulted was a design that was a development of the Aylwin class, which itself was similar to the first of the thousand tonners. The key difference in the OBrien class was the increase in torpedo size, the ships had a median displacement of 1,050 long tons, were just over 305 feet in length, and had a beam of about 31 feet. All of the ships had two steam turbines and a combination of other engines for cruising at speeds less than 15 knots. All of the ships were designed for a speed of 29 knots. As built, they were armed with four 4-inch guns and had four twin 21-inch torpedo tubes with a load of eight torpedoes, Navy between June 1914 and August 1915. All six ships operated in the Atlantic or Caribbean until the U. S. entrance into World War I in April 1917, all six members of the class had returned to the United States in January 1919 and were decommissioned by June 1922. In 1924, two of the six—Ericsson and McDougal—were commissioned into the United States Coast Guard to help enforce Prohibition as a part of the Rum Patrol and they were returned to U. S. Navy custody in 1932 and 1933, respectively. All six ships had been sold for scrapping by June 1936, for the 1913 fiscal year, the General Board of the United States Navy determined that six destroyers would be authorized. The design for Destroyers No.51 through No, 56—what became the OBrien class, was to closely follow the design of the Cassin and Aylwin classes from fiscal year 1912. The chief of the U. S. Navys Bureau of Ordnance suggested that the new destroyers be equipped with ten torpedo tubes and urged that the new 21-inch torpedo be adopted. The additional weight of the torpedoes,5 long tons of top weight, was offset by reducing the planned two aft-facing guns to a single one. This gave the class four 4-inch guns, which, again, the design for the OBrien class was approved on 20 August 1912, and authorized by Congress on 4 March 1913. As built, the OBrien-class ships were 305 feet 5 inches in length, were 31 feet 2 inches abeam, and had a standard draft of 9 feet 6 inches. The hull shape featured the high forecastle typical of U. S. destroyer classes since the 1908–09 Smith class. The ships displaced between 1,020 and 1,090 long tons with a median of 1,050 long tons, the ships were equipped with two propeller shafts and two direct-drive, Zoelly steam turbines fed by four White-Forster boilers. The power plant of the ships generated 17,000 shaft horsepower which drive the ships to the speed of 29 knots
10.
Clemson-class destroyer
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The Clemson class was a series of 156 destroyers which served with the United States Navy from after World War I through World War II. The Clemson class was a redesign of the Wickes class for greater fuel capacity. As finally built, the Clemson class would be a fairly straightforward expansion of the Wickes-class destroyers and these designs included a reduction in speed to between 26–28 knots by eliminating two boilers, freeing up displacement for depth charges and more fuel. This proposal foreshadowed the destroyer escorts of World War II, upgrading the gun armament from 4-inch to 5-inch guns was also considered, but only five ships were armed with 5-inch guns. In addition, the stern of the Wickes-class destroyers resulted in a large turning radius. In the end the General Board decided the 35 knots speed be retained so as to allow the Clemson class to be used as a fleet escort, the pressing need for destroyers overruled any change that would slow production compared to the proceeding Wickes class. Wing tanks for oil were installed on either side of the ships to increase the operational range. This design choice meant the oil would be stored above the waterline and create additional vulnerability. The class resulted from a General Board recommendation for further destroyers to combat the threat, culminating in a total of 267 Wickes-. However, the design of the ships remained optimized for operation with the battleship fleet, the main armament was the same as the Wickes class, four 4-inch /50 caliber guns and twelve 21-inch torpedo tubes. Although the design provided for two guns, most ships carried a single 3-inch /23 caliber AA gun, typically on the aft deckhouse. A frequent modification was replacing the aft 4-inch gun with the 3-inch gun to more room for the depth charge tracks. Anti-submarine armament was added during or after construction, typically, two depth charge tracks were provided aft, along with a Y-gun depth charge projector forward of the aft deckhouse. Despite the provision for 5-inch guns, only seven ships were built with a gun armament. USS Hovey and USS Long had twin 4-inch/50 mounts for a total of eight guns, while an increased rudder size helped, the answer would be in a redesigned stern, but this was not implemented. They were reported to be prone to rolling in light load conditions. The flush deck gave the great strength but this also made the deck very wet. Fourteen ships of the class were involved in the Honda Point Disaster in 1923, many never saw wartime service, as a significant number were decommissioned in 1930 and scrapped as part of the London Naval Treaty
11.
Anti-aircraft warfare
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Anti-aircraft warfare or counter-air defence is defined by NATO as all measures designed to nullify or reduce the effectiveness of hostile air action. They include ground-and air-based weapon systems, associated sensor systems, command and control arrangements and it may be used to protect naval, ground, and air forces in any location. However, for most countries the main effort has tended to be homeland defence, NATO refers to airborne air defence as counter-air and naval air defence as anti-aircraft warfare. Missile defence is an extension of air defence as are initiatives to adapt air defence to the task of intercepting any projectile in flight, a surface-based air defence capability can also be deployed offensively to deny the use of airspace to an opponent. Until the 1950s, guns firing ballistic munitions ranging from 20 mm to 150 mm were the weapons, guided missiles then became dominant. The term air defence was probably first used by Britain when Air Defence of Great Britain was created as a Royal Air Force command in 1925. However, arrangements in the UK were also called anti-aircraft, abbreviated as AA, after the First World War it was sometimes prefixed by Light or Heavy to classify a type of gun or unit. Nicknames for anti-aircraft guns include AA, AAA or triple-A, an abbreviation of anti-aircraft artillery, ack-ack, NATO defines anti-aircraft warfare as measures taken to defend a maritime force against attacks by airborne weapons launched from aircraft, ships, submarines and land-based sites. In some armies the term All-Arms Air Defence is used for air defence by nonspecialist troops, other terms from the late 20th century include GBAD with related terms SHORAD and MANPADS. Anti-aircraft missiles are variously called surface-to-air missile, abbreviated and pronounced SAM, non-English terms for air defence include the German FlaK, whence English flak, and the Russian term Protivovozdushnaya oborona, a literal translation of anti-air defence, abbreviated as PVO. In Russian the AA systems are called zenitnye systems, in French, air defence is called DCA. The maximum distance at which a gun or missile can engage an aircraft is an important figure, however, many different definitions are used but unless the same definition is used, performance of different guns or missiles cannot be compared. For AA guns only the part of the trajectory can be usefully used. By the late 1930s the British definition was that height at which an approaching target at 400 mph can be engaged for 20 seconds before the gun reaches 70 degrees elevation. However, effective ceiling for heavy AA guns was affected by nonballistic factors, The maximum running time of the fuse, the capability of fire control instruments to determine target height at long range. The essence of air defence is to detect aircraft and destroy them. The critical issue is to hit a target moving in three-dimensional space, Air defence evolution covered the areas of sensors and technical fire control, weapons, and command and control. At the start of the 20th century these were very primitive or non-existent
12.
Anti-submarine weapon
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An anti-submarine weapon is any one of a number of devices that are intended to act against a submarine and its crew, to destroy the vessel or reduce its capability as a weapon of war. In its simplest sense, a weapon is usually a projectile, missile or bomb that is optimized to destroy submarines. Prior to about 1890, naval weapons were used against surface shipping. With the rise of the submarine after this time, countermeasures were considered for use against them. The first submarine installation of tubes was in 1885 and the first ship was sunk by a submarine-launched torpedo in 1887. There were only two ways of countering the military initially, ramming them or sinking them with gunfire. However, once they were submerged, they were largely immune until they had to surface again, by the start of the First World War there were nearly 300 submarines in service with another 80 in production. World War I marked the first earnest conflict involving significant use of submarines, in particular, the United Kingdom was desperate to defeat the U-Boat threat against British merchant shipping. When the bombs that it employed were found to be ineffective it began equipping its destroyers with simple depth charges that could be dropped into the water around a suspected submarines location. During this period it was found that explosions of these charges were more efficient if the charges were set to explode below or above the submarine, however, many other techniques were used, including minefields, barrages and Q-ships and the use of cryptanalysis against intercepted radio messages. The airship was used to drop bombs but fixed-wing aircraft were used for reconnaissance. However, the most effective countermeasure was the convoy, in 1918 U-boat losses became unbearably high. Most of the losses were due to mines but two were torpedoed, french, Italian and Russian submarines were also destroyed. Before the war ended, the need for forward-throwing weapons had been recognized by the British, hydrophones had been developed and were becoming effective as detection and location devices. Also, aircraft and airships had flown with depth bombs, albeit small ones with poor explosives. In addition, the specialist hunter-killer submarine had appeared, HMS R-1, the main developments in this period were in detection, with both active sonar and radar becoming effective. The British integrated the sonar with fire control and weapons to form a system for warships. Germany was banned from having a fleet but began construction in secret during the 1930s
