Keelung known as Keelung City, is a major port city situated in the northeastern part of Taiwan. It borders New Taipei with which it forms the Taipei–Keelung metropolitan area, along with Taipei itself. Nicknamed the Rainy Port for its frequent rain and maritime role, the city is Taiwan's second largest seaport. According to early Chinese accounts, this northern coastal area was called Pak-kang. By the early 20th century, the city was known to the Western world as Kelung, as well as the variants Kiloung and Keelung. In his 1903 general history of Taiwan, US Consul to Formosa James W. Davidson related that "Kelung" was among the few well-known names, thus warranting no alternate Japanese romanization. However, the Taiwanese people have long called the city Kelang, it has been proposed that this name was derived from the local mountain that took the shape of a rooster cage. However, it is more probable that the name was derived from the first inhabitants of the region, as are the names of many other Taiwanese cities.
In this case, the Ketagalan people were the first inhabitants, early Han settlers approximated "Ketagalan" with Ke-lâng. In 1875, during the late Qing era, a new official name was given. In Mandarin the working language of Chinese government at the time, both the old and new names were pronounced Kīlóng. Under Japanese rule, the city was known to the west by the Japanese romanization Kīrun. In Standard Chinese, which became the official language of Taiwan after its handover to the Republic of China, the newer name is read Jīlóng. However, the locals continue to call the city Ke-lâng across the changes in government. Keelung was first inhabited by a tribe of Taiwanese aborigine; the Spanish expedition to Formosa in the early 17th century was its first contact with the West. The Spanish ruled it as a part of Spanish Formosa. From 1642 to 1661 and 1663–1668, Keelung was under Dutch control; the Dutch East India Company took over the Spanish Fort San Salvador at Santissima Trinidad. They renamed it Fort Noort-Hollant.
The Dutch had three more minor fortifications in Keelung and a little school and a preacher. When Ming Dynasty loyalist Koxinga attacked the Dutch in southern Taiwan, the crew of the Keelung forts fled to the Dutch trading post in Japan; the Dutch strengthened their earlier forts. However, trade with Qing China through Keelung was not what they hoped it would be and, in 1668, they left after getting harassed by aboriginals. Given the strategic and commercial value of Taiwan, there were British suggestions in 1840 and 1841 to seize the island. In September 1841, during the First Opium War, the British transport ship Nerbudda became shipwrecked near Keelung Harbour due to a typhoon; the brig Ann became shipwrecked in March 1842. Most of the crew were Indian lascars. Survivors from both ships were transferred by authorities to the capital Tainan; the Taiwan Qing commanders, Ta-hung-ah and Yao Ying, filed a disingenuous report to the emperor, claiming to have defended against an attack from the Keelung fort.
In October 1841, HMS Nimrod sailed to Keelung to search for the Nerbudda survivors, but after Captain Joseph Pearse found out that they were sent south for imprisonment, he ordered the bombardment of the harbour and destroyed 27 sets of cannon before returning to Hong Kong. Most of the survivors—over 130 from the Nerbudda and 54 from the Ann—were executed in Tainan in August 1842. In 1863, the Qing Empire opened up Keelung as a trading port and the city enjoyed rapid development due to the abundant commodities such as placer gold and high quality coal found in the drainage area of Keelung River. In 1875, Taipeh Prefecture was included Keelung. In 1878, Keelung was formed into a sub-prefecture. Around the same time, the name was changed from Ke-lang to Kilong, which means "rich and prosperous land". During the Sino-French War, the French attempted an invasion of Taiwan during the Keelung Campaign. Liu Mingchuan, who led the defence of Taiwan, recruited Aboriginals to serve alongside the Chinese soldiers in fighting against the French of Colonel Jacques Duchesne's Formosa Expeditionary Corps.
The French were defeated at the Battle of Tamsui and the Qing forces pinned the French down at Keelung in an eight-month-long campaign before the French withdrew. A systematic city development started during the Japanese Era, after the 1895 Treaty of Shimonoseki, which handed all Taiwan over to Japan. A five-phase construction of Keelung Harbor was initiated, in by 1916 trade volume had exceeded those of Tamsui and Kaohsiung Harbors to become one of the major commercial harbors of Taiwan. Keelung was governed as Kīrun Town, Kīrun District, Taihoku Prefecture in 1920 and was upgraded to a city in 1924; the Pacific War broke out in 1941, Keelung became one of the first targets of Allied bombers and was nearly destroyed as a result. After the handover of Taiwan from Japan to the Republic of China in October 1945, Keelung was established as a provincial city of Taiwan Province; the Keelung City Government worked with the harbor bureau to rebuild the city and the harbor
Pearl Harbor is a lagoon harbor on the island of Oahu, west of Honolulu. It has been long visited by the Naval fleet of the United States, before it was acquired from the Hawaiian Kingdom by the U. S. with the signing of the Reciprocity Treaty of 1875. Much of the harbor and surrounding lands is now a United States Navy deep-water naval base, it is the headquarters of the United States Pacific Fleet. The U. S. government first obtained exclusive use of the inlet and the right to maintain a repair and coaling station for ships here in 1887. The attack on Pearl Harbor by the Empire of Japan on December 7, 1941, was the immediate cause of the United States' entry into World War II. Pearl Harbor was an extensive shallow embayment called Wai Momi or Puʻuloa by the Hawaiians. Puʻuloa was regarded as the home of the shark goddess, Kaʻahupahau, her brother, Kahiʻuka, in Hawaiian legends. According to tradition, the head of the powerful Ewa chiefs, is credited with cutting a navigable channel near the present Puʻuloa saltworks, by which he made the estuary, known as "Pearl River," accessible to navigation.
Making due allowance for legendary amplification, the estuary had an outlet for its waters where the present gap is. During the early 19th century, Pearl Harbor was not used for large ships due to its shallow entrance; the interest of United States in the Hawaiian Islands grew as a result of its whaling and trading activity in the Pacific. As early as 1820, an "Agent of the United States for Commerce and Seamen" was appointed to look after American business in the Port of Honolulu; these commercial ties to the American continent were accompanied by the work of the American Board of Commissioners for Foreign Missions. American missionaries and their families became an integral part of the Hawaiian political body. Throughout the 1820s and 1830s, many American warships visited Honolulu. In most cases, the commanding officers carried letters from the U. S. Government giving advice on governmental affairs and of the relations of the island nation with foreign powers. In 1841, the newspaper Polynesian, printed in Honolulu, advocated that the U.
S. establish a naval base in Hawaii for protection of American citizens engaged in the whaling industry. The British Hawaiian Minister of Foreign Affairs Robert Crichton Wyllie, remarked in 1840 that "... my opinion is that the tide of events rushes on to annexation to the United States." From the conclusion of the Civil War, to the purchase of Alaska, to the increased importance of the Pacific states, the projected trade with countries in Asia and the desire for a duty-free market for Hawaiian staples, Hawaiian trade expanded. In 1865, the North Pacific Squadron was formed to embrace Hawaii. Lackawanna in the following year was assigned to cruise among the islands, "a locality of great and increasing interest and importance." This vessel surveyed the Northwestern Hawaiian Islands toward Japan. As a result, the United States claimed Midway Island; the Secretary of the Navy was able to write in his annual report of 1868, that in November 1867, 42 American flags flew over whaleships and merchant vessels in Honolulu to only six of other nations.
This increased activity caused the permanent assignment of at least one warship to Hawaiian waters. It praised Midway Island as possessing a harbor surpassing Honolulu's. In the following year, Congress approved an appropriation of $50,000 on March 1, 1869, to deepen the approaches to this harbor. After 1868, when the Commander of the Pacific Fleet visited the islands to look after American interests, naval officers played an important role in internal affairs, they served as arbitrators in business disputes, negotiators of trade agreements and defenders of law and order. Periodic voyages among the islands and to the mainland aboard U. S. warships were arranged for members of the Hawaiian royal family and important island government officials. When King Lunalilo died in 1873, negotiations were underway for the cession of Pearl Harbor as a port for the duty-free export of sugar to the U. S. With the election of King Kalākaua in March 1874, riots prompted landing of sailors from USS Tuscarora and Portsmouth.
The British warship, HMS Tenedos landed a token force. During the reign of King Kalākaua the United States was granted exclusive rights to enter Pearl Harbor and to establish "a coaling and repair station." Although this treaty continued in force until August 1898, the U. S. did not fortify Pearl Harbor as a naval base. As it had for 60 years, the shallow entrance constituted a formidable barrier against the use of the deep protected waters of the inner harbor; the United States and the Hawaiian Kingdom signed the Reciprocity Treaty of 1875 as supplemented by Convention on December 6, 1884, the Reciprocity Treaty was made by James Carter and ratified it in 1887. On January 20, 1887, the United States Senate allowed the Navy to exclusive right to maintain a coaling and repair station at Pearl Harbor.. The Spanish–American War of 1898 and the desire for the United States to have a permanent presence in the Pacific both contributed to the decision. Following the overthrow of the Hawaiian Kingdom, the United States Navy established a base on the island in 1899.
On December 7, 1941, the base was attacked by the Imperial Japanese Navy airplanes and midget submarines, causing the American entry into World War II. One of the main reasons that Pearl Harbor happened was because the United States had major communication breakdowns among several branches of the U. S. armed services and departments of the U. S. government. This led to the surprise Japanese attack at the Hawai
The United States of America known as the United States or America, is a country composed of 50 states, a federal district, five major self-governing territories, various possessions. At 3.8 million square miles, the United States is the world's third or fourth largest country by total area and is smaller than the entire continent of Europe's 3.9 million square miles. With a population of over 327 million people, the U. S. is the third most populous country. The capital is Washington, D. C. and the largest city by population is New York City. Forty-eight states and the capital's federal district are contiguous in North America between Canada and Mexico; the State of Alaska is in the northwest corner of North America, bordered by Canada to the east and across the Bering Strait from Russia to the west. The State of Hawaii is an archipelago in the mid-Pacific Ocean; the U. S. territories are scattered about the Pacific Ocean and the Caribbean Sea, stretching across nine official time zones. The diverse geography and wildlife of the United States make it one of the world's 17 megadiverse countries.
Paleo-Indians migrated from Siberia to the North American mainland at least 12,000 years ago. European colonization began in the 16th century; the United States emerged from the thirteen British colonies established along the East Coast. Numerous disputes between Great Britain and the colonies following the French and Indian War led to the American Revolution, which began in 1775, the subsequent Declaration of Independence in 1776; the war ended in 1783 with the United States becoming the first country to gain independence from a European power. The current constitution was adopted in 1788, with the first ten amendments, collectively named the Bill of Rights, being ratified in 1791 to guarantee many fundamental civil liberties; the United States embarked on a vigorous expansion across North America throughout the 19th century, acquiring new territories, displacing Native American tribes, admitting new states until it spanned the continent by 1848. During the second half of the 19th century, the Civil War led to the abolition of slavery.
By the end of the century, the United States had extended into the Pacific Ocean, its economy, driven in large part by the Industrial Revolution, began to soar. The Spanish–American War and World War I confirmed the country's status as a global military power; the United States emerged from World War II as a global superpower, the first country to develop nuclear weapons, the only country to use them in warfare, a permanent member of the United Nations Security Council. Sweeping civil rights legislation, notably the Civil Rights Act of 1964, the Voting Rights Act of 1965 and the Fair Housing Act of 1968, outlawed discrimination based on race or color. During the Cold War, the United States and the Soviet Union competed in the Space Race, culminating with the 1969 U. S. Moon landing; the end of the Cold War and the collapse of the Soviet Union in 1991 left the United States as the world's sole superpower. The United States is the world's oldest surviving federation, it is a representative democracy.
The United States is a founding member of the United Nations, World Bank, International Monetary Fund, Organization of American States, other international organizations. The United States is a developed country, with the world's largest economy by nominal GDP and second-largest economy by PPP, accounting for a quarter of global GDP; the U. S. economy is post-industrial, characterized by the dominance of services and knowledge-based activities, although the manufacturing sector remains the second-largest in the world. The United States is the world's largest importer and the second largest exporter of goods, by value. Although its population is only 4.3% of the world total, the U. S. holds 31% of the total wealth in the world, the largest share of global wealth concentrated in a single country. Despite wide income and wealth disparities, the United States continues to rank high in measures of socioeconomic performance, including average wage, human development, per capita GDP, worker productivity.
The United States is the foremost military power in the world, making up a third of global military spending, is a leading political and scientific force internationally. In 1507, the German cartographer Martin Waldseemüller produced a world map on which he named the lands of the Western Hemisphere America in honor of the Italian explorer and cartographer Amerigo Vespucci; the first documentary evidence of the phrase "United States of America" is from a letter dated January 2, 1776, written by Stephen Moylan, Esq. to George Washington's aide-de-camp and Muster-Master General of the Continental Army, Lt. Col. Joseph Reed. Moylan expressed his wish to go "with full and ample powers from the United States of America to Spain" to seek assistance in the revolutionary war effort; the first known publication of the phrase "United States of America" was in an anonymous essay in The Virginia Gazette newspaper in Williamsburg, Virginia, on April 6, 1776. The second draft of the Articles of Confederation, prepared by John Dickinson and completed by June 17, 1776, at the latest, declared "The name of this Confederation shall be the'United States of America'".
The final version of the Articles sent to the states for ratification in late 1777 contains the sentence "The Stile of this Confederacy shall be'The United States of America'". In June 1776, Thomas Jefferson wrote the phrase "UNITED STATES OF AMERICA" in all capitalized letters in the headline of his "original Rough draught" of the Declaration of Independence; this draft of the document did not surface unti
Boeing B-29 Superfortress
The Boeing B-29 Superfortress is a four-engine propeller-driven heavy bomber designed by Boeing, flown by the United States during World War II and the Korean War. It was one of the largest aircraft operational during World War II and featured state-of-the-art technology. Including design and production, at over $3 billion it was the most expensive weapons project in the war, exceeding the $1.9 billion cost of the Manhattan Project—using the value of dollars in 1945. Innovations introduced included a pressurized cabin, dual-wheeled, tricycle landing gear, an analog computer-controlled fire-control system directing four remote machine gun turrets that could be operated by one gunner and a fire-control officer. A manned tail gun installation was semi-remote; the name "Superfortress" continued the pattern Boeing started with its well-known predecessor, the B-17 Flying Fortress. Designed for the high-altitude strategic bombing, the B-29 excelled in low-altitude night incendiary bombing. One of the B-29's final roles during World War II was carrying out the atomic bomb attacks on Hiroshima and Nagasaki.
Because of the B-29's advanced design, unlike other wartime bombers, the Superfortress remained in service long after the war ended, with a few being employed as flying television transmitters for the Stratovision company. The B-29 served in various roles throughout the 1950s; the Royal Air Force flew the B-29 as the Washington until 1954. The Soviet Union produced an unlicensed reverse-engineered copy as the Tupolev Tu-4; the B-29 was the progenitor of a series of Boeing-built bombers, tankers, reconnaissance aircraft and trainers including the B-50 Superfortress, a re-engined B-29. The type was retired in the early 1960s. Dozens of B-29s remain as static displays but only two examples and Doc, have been restored to flying status, with Doc flying again for the first time from McConnell AFB on 17 July 2016. A transport developed from the B-29 was the Boeing C-97 Stratofreighter, first flown in 1944, followed by its commercial airliner variant, the Boeing Model 377 Stratocruiser in 1947; this bomber-to-airliner derivation was similar to the B-17/Model 307 evolution.
In 1948 Boeing introduced a tanker variant of the B-29 as the KB-29, followed by the Model 377-derivative KC-97 introduced in 1950. A modified line of outsized-cargo variants of the Stratocruiser is the Guppy / Mini Guppy / Super Guppy, which remain in service with operators including NASA; the Boeing B-17 Flying Fortress served as the United States' primary strategic bomber during World War II. However, this aircraft was deemed inadequate for use in the Pacific Theater; the United States Army Air Corps concluded that a long range bomber that could carry a larger payload over 3000 miles was necessary. In response, Boeing began work on pressurized long-range bombers in 1938. Boeing's design study for the Model 334 was a pressurized derivative of the Boeing B-17 Flying Fortress with nosewheel undercarriage. Although the Air Corps did not have money to pursue the design, Boeing continued development with its own funds as a private venture. In April 1939, Charles Lindbergh convinced general Henry H.
Arnold to produce a new bomber in large numbers to counter the Nazi production. The Air Corps issued a formal specification for a so-called "superbomber", capable of delivering 20,000 lb of bombs to a target 2,667 mi away and capable of flying at a speed of 400 mph in December 1939. Boeing's previous private venture studies formed the starting point for its response to this specification. Boeing submitted its Model 345 on 11 May 1940, in competition with designs from Consolidated Aircraft and Douglas. Douglas and Lockheed soon abandoned work on their projects, but Boeing received an order for two flying prototypes, given the designation XB-29, an airframe for static testing on 24 August 1940, with the order being revised to add a third flying aircraft on 14 December. Consolidated continued to work on its Model 33 as it was seen by the Air Corps as a backup in case of problems with Boeing's design. Boeing received an initial production order for 14 service test aircraft and 250 production bombers in May 1941, this being increased to 500 aircraft in January 1942.
The B-29 featured a fuselage design with circular cross-section for strength. The need for pressurization in the cockpit area led to the B-29 being one of few American combat aircraft of World War II to have a stepless cockpit design, without a separate windscreen for the pilots. Manufacturing the B-29 was a complex task, it involved four main-assembly factories: a pair of Boeing operated plants at Renton and Wichita, Kansas, a Bell plant at Marietta, Georgia near Atlanta, a Martin plant at Omaha, Nebraska. Thousands of subcontractors were involved in the project; the first prototype made its maiden flight from Boeing Field, Seattle on 21 September 1942. The combined effects of the aircraft's advanced design, challenging requirements, immense pressure for production, hurried development caused setbacks; the second prototype, unlike the unarmed first, was fitted with a Sperry defensive armament system using remote-controlled gun turrets sighted by periscopes, first flew on 30 December 1942, this flight being terminated due to a serious engine fire.
On 18 February 1943, the second prototype, flying out of Boeing Field in Seattle, experienced an engine fire and crashed. The crash killed Boeing test pilot Edmund T. Allen and his 10-man crew, 20 worker
Oerlikon 20 mm cannon
The Oerlikon 20 mm cannon is a series of autocannons, based on an original German 20 mm Becker design that appeared early in World War I. It was produced by Oerlikon Contraves and others, with various models employed by both Allied and Axis forces during World War II, many versions still in use today. During World War I, the German industrialist Reinhold Becker developed a 20 mm caliber cannon, known now as the 20 mm Becker using the Advanced Primer Ignition blowback method of operation; this had a cyclic rate of fire of 300 rpm. It was used on a limited scale as an aircraft gun on Luftstreitkräfte warplanes, an anti-aircraft gun towards the end of that war; because the Treaty of Versailles banned further production of such weapons in Germany, the patents and design works were transferred in 1919 to the Swiss firm SEMAG based near Zürich. SEMAG continued development of the weapon, in 1924 had produced the SEMAG L, a heavier weapon that fired more powerful 20x100RB ammunition at a higher rate of fire, 350 rpm.
In 1924 SEMAG failed. The Oerlikon firm, named after the Zürich suburb of Oerlikon where it was based acquired all rights to the weapon, plus the manufacturing equipment and the employees of SEMAG. In 1927 the Oerlikon S was added to the existing product line; this fired a still larger cartridge to achieve a muzzle velocity of 830 m/s, at the cost of increased weight and a reduced rate of fire. The purpose of this development was to improve the performance of the gun as an anti-tank and anti-aircraft weapon, which required a higher muzzle velocity. An improved version known as the 1S followed in 1930. Three sizes of gun with their different ammunition and barrel length, but similar mechanisms, continued to be developed in parallel. In 1930 Oerlikon reconsidered the application of its gun in aircraft and introduced the AF and AL, designed to be used in flexible mounts, i.e. manually aimed by a gunner. The 15-round box magazine used by earlier versions of the gun was replaced by drum magazine holding 15 or 30 rounds.
In 1935 it made an important step by introducing a series of guns designed to be mounted in or on the wings of fighter aircraft. Designated with FF for Flügelfest meaning "wing-mounted", these weapons were again available in the three sizes, with designations FF, FFL and FFS; the FF fired a larger cartridge than the AF, 20x72RB, but the major improvement in these weapons was a significant increase in rate of fire. The FF weighed 24 kg and achieved a muzzle velocity of 550 to 600 m/s with a rate of fire of 520 rpm; the FFL of 30 kg fired a projectile at a muzzle velocity of 675 m/s with a rate of fire of 500 rpm. And the FFS, which weighed 39 kg, delivered a high muzzle velocity of 830 m/s at a rate of fire of 470 rpm. Apart from changes to the design of the guns for wing-mounting and remote control, larger drums were introduced as it would not be possible to exchange magazines in flight. For the FF series drum sizes of 45, 60, 75 and 100 rounds were available, but most users chose the 60-round drum.
The 1930s were a period of global re-armament, a number of foreign firms took licenses for the Oerlikon family of aircraft cannon. In France, Hispano-Suiza manufactured development of the FFS as the Hispano-Suiza HS.7 and Hispano-Suiza HS.9, for installation between the cylinder banks of its V-12 engines. In Germany, Ikaria further developed the FF gun as firing 20x80RB ammunition, and the Imperial Japanese Navy, after evaluating all three guns, ordered developments of the FF and FFL as the Type 99-1 and Type 99-2. The incorporation of the improvements of the FFS in a new anti-aircraft gun produced, in 1938, the Oerlikon SS. Oerlikon realized further improvements in rate of fire on the 1SS of 1942, the 2SS of 1945 which achieved 650 rpm. However, it was the original SS gun, adopted as anti-aircraft gun, being widely used by Allied navies during World War II; this gun used a 400-grain charge of IMR 4831 smokeless powder to propel a 2,000-grain projectile at 2,800 feet per second. The Oerlikon FF was installed as armament on some fighters of the 1930s, such as the Polish PZL P.24G.
Locally produced derivatives of the Oerlikon cannon were used much more extensively, on aircraft, on ships and on land. In the air, the Ikaria MG FF was used as armament on a number of German aircraft, of which the most famous is the Messerschmitt Bf 109; the Japanese Navy used their copy of the FF, designated the Type 99 Mark One cannon on a number of types including the Mitsubishi A6M Zero. In the war, they equipped fighters including the Zero with the Type 99 Mark Two, a version of the more powerful and faster-firing Oerlikon FFL; the French firm of Hispano-Suiza was a manufacturer of aircraft engines, it marketed the moteur-canon combination of its 12X and 12Y engines with a H. S.7 or H. S.9 cannon installed between the cylinder banks. The gun fired through the hollow propeller hub, this being elevated above the crankcase by the design of the gearing; such armament was installed on the Morane-Saulnier M. S.406 and some other types. Similar German installations of the MG FF were not successful.
The Oerlikon became best known in its naval applications. The Oerlikon was not looked upon favorably by the Royal Navy as a short-range anti-aircraft gun. All through 1937-1938 Lord Louis Mountbatten a Captain in the Royal Navy, waged a lone campaign within the Royal Navy to set up an unprejudiced trial for the Oerlikon 20 mm gun, but it was all in vain, it was not until the Commander-in-Chief of the Home Fleet, Admiral Sir Roger Backhouse, was appointed First Sea Lord tha
The Hedgehog was a forward-throwing anti-submarine weapon, used during the Battle of the Atlantic in the Second World War. The device, developed by the Royal Navy, fired up to 24 spigot mortars ahead of a ship when attacking a U-boat, it was deployed on convoy escort warships such as destroyers and corvettes to supplement the depth charges. As the mortar projectiles employed contact fuzes rather than time or barometric fuzes, detonation occurred directly against a hard surface such as the hull of a submarine making it more deadly than depth charges, which relied on damage caused by hydrostatic shockwaves. Statistics show that during WWII out of 5,174 British depth charge attacks there were 85.5 kills: a ratio of 60.5 to 1. In comparison, the Hedgehog made 268 attacks for 47 kills: a ratio of 5.7 to 1. The "Hedgehog", so named because the empty rows of its launcher spigots resembled the spines of a hedgehog, was a replacement for the unsuccessful Fairlie Mortar, trialled aboard HMS Whitehall in 1941.
Although a failure, the Fairlie was designed to fire depth charges ahead of a ship when attacking a submarine. This principle of forward-firing projectiles was considered viable; this secret research by the Directorate of Miscellaneous Weapons Development led to the development of the Hedgehog. The weapon was a multiple'spigot mortar' or spigot discharger, a type of weapon developed between the wars by Lieutenant Colonel Stewart Blacker, RA; the spigot mortar was based on early infantry trench mortars. The spigot design allowed a single device to fire warheads of varying size; the propelling charge was part of the main weapon and worked against a rod set in the baseplate which fitted inside a tubular tail of the'bomb'. This principle was first used on the Blacker Bombard 29 mm Spigot Mortar and the PIAT anti-tank weapon; the adaptation of the bombard for naval use was made in partnership with MIR under Major Millis Jefferis who had taken Blacker's design and brought it into use with Army. The weapon fires a salvo of 24 bombs in an arc, aimed to land in a circular or elliptical area about 100 feet in diameter at a fixed point about 250 yards directly ahead of the attacking ship.
The mounting was fixed but was replaced by a gyro-stabilised one to allow for the rolling and pitching of the attacking ship. The system was developed to solve the problem of the target submarine disappearing from the attacking ship's ASDIC when the ship came within the sonar's minimum range. Due to the speed of sound in water, the time taken for the'ping' echo to return to the attacking ship from the target submarine became too short to allow the human operator to distinguish the returning audible echo from that of the initial sound pulse emitted by the sonar – the so-called "instantaneous echo", where the output sound pulse and returning echo merge; this "blind spot" allowed the submarine to make evasive manoeuvres undetected while the ship was out of range for depth charge attack. Hence, the submarine was invisible to the sonar as the ship came within the sonar's minimum range; the solution was a weapon mounted on the foredeck that discharged the projectiles up and over that carrying ship's bow, to land in the water some distance in front of the ship while the submarine was still outside the sonar's minimum range.
The Hedgehog entered service in 1942. Carrying a Torpex charge weighing 16 kg, each mortar had a diameter of 18 cm and weighed about 29.5 kg. The projectiles were angled so they would land in a circular shape with a diameter of 40 m about 180 m ahead of a stationary ship; the projectiles would sink at about 7 m/s. They would reach a submerged U-boat, for example at 200 ft in under 9 seconds. Sympathetic detonation of projectiles near those contacting hard surfaces was a possibility, but the number of explosions counted was fewer than the number of projectiles launched; the prototype launcher was tested aboard HMS Westcott in 1941, but there were no submarine kills until November 1942, after it had been installed aboard one hundred ships. Initial success rates – of about 5% – were only better than depth charges. Swells and spray covered the launcher during heavy North Atlantic weather, subsequent attempts to launch revealed firing circuit problems launching an incomplete pattern; the disappointment of a quiet miss discouraged crews who might otherwise assume depth charge explosions had damaged their target or at least frightened the enemy.
The Royal Navy launched Hedgehog so in early 1943 that a directive was issued ordering captains of ships equipped with Hedgehog to report why they had not used Hedgehog on an underwater contact. The results were blamed on low confidence in the weapon. However, after an officer from the DMWD was sent to Londonderry Port, where the convoy crews were based, with better training and shipwide talks on examples of successful Hedgehog attacks, the kill rate improved considerably. By the end of the war, statistics showed that on average, one in every five attacks made by Hedgehog resulted in a kill. In response to this new deadly threat to its U-boats, the Kriegsmarine brought forward its programme of acoustic torpedoes in 1943, beginning with the Falke; these new "homing" torpedoes could be employed without the use of a periscope, providing submarines a better chance to remain undetected and evade counterattack. In the Pacific Theater, USS England sank six Japanese submarines in a matter of days with Hedgehog in May 1944.
In 1946, USS Solar was destroyed after a crewman accidentally dropped a Hedgehog charge near one of her main turret am
A submarine is a watercraft capable of independent operation underwater. It differs from a submersible, it is sometimes used or colloquially to refer to remotely operated vehicles and robots, as well as medium-sized or smaller vessels, such as the midget submarine and the wet sub. Although experimental submarines had been built before, submarine design took off during the 19th century, they were adopted by several navies. Submarines were first used during World War I, are now used in many navies large and small. Military uses include attacking enemy surface ships, attacking other submarines, aircraft carrier protection, blockade running, ballistic missile submarines as part of a nuclear strike force, conventional land attack, covert insertion of special forces. Civilian uses for submarines include marine science, salvage and facility inspection and maintenance. Submarines can be modified to perform more specialized functions such as search-and-rescue missions or undersea cable repair. Submarines are used in tourism, for undersea archaeology.
Most large submarines consist of a cylindrical body with hemispherical ends and a vertical structure located amidships, which houses communications and sensing devices as well as periscopes. In modern submarines, this structure is the "sail" in American usage and "fin" in European usage. A "conning tower" was a feature of earlier designs: a separate pressure hull above the main body of the boat that allowed the use of shorter periscopes. There is a propeller at the rear, various hydrodynamic control fins. Smaller, deep-diving and specialty submarines may deviate from this traditional layout. Submarines use diving planes and change the amount of water and air in ballast tanks to change buoyancy for submerging and surfacing. Submarines have one of the widest ranges of capabilities of any vessel, they range from small autonomous examples and one- or two-person vessels that operate for a few hours, to vessels that can remain submerged for six months—such as the Russian Typhoon class, the biggest submarines built.
Submarines can work at greater depths than are practical for human divers. Modern deep-diving submarines derive from the bathyscaphe, which in turn evolved from the diving bell. Whereas the principal meaning of "submarine" is an armed, submersible warship, the more general meaning is for any type of submersible craft; the definition as of 1899 was for any type of "submarine boat". By naval tradition, submarines are still referred to as "boats" rather than as "ships", regardless of their size. In other navies with a history of large submarine fleets they are "boats". According to a report in Opusculum Taisnieri published in 1562: Two Greeks submerged and surfaced in the river Tagus near the City of Toledo several times in the presence of The Holy Roman Emperor Charles V, without getting wet and with the flame they carried in their hands still alight. In 1578, the English mathematician William Bourne recorded in his book Inventions or Devises one of the first plans for an underwater navigation vehicle.
A few years the Scottish mathematician and theologian John Napier wrote in his Secret Inventions the following: "These inventions besides devises of sayling under water with divers, other devises and strategems for harming of the enemyes by the Grace of God and worke of expert Craftsmen I hope to perform." It's unclear whether he carried out his idea. The first submersible of whose construction there exists reliable information was designed and built in 1620 by Cornelis Drebbel, a Dutchman in the service of James I of England, it was propelled by means of oars. By the mid-18th century, over a dozen patents for submarines/submersible boats had been granted in England. In 1747, Nathaniel Symons patented and built the first known working example of the use of a ballast tank for submersion, his design used leather bags. A mechanism was used to cause the boat to resurface. In 1749, the Gentlemen's Magazine reported that a similar design had been proposed by Giovanni Borelli in 1680. Further design improvement stagnated for over a century, until application of new technologies for propulsion and stability.
The first military submarine was the Turtle, a hand-powered acorn-shaped device designed by the American David Bushnell to accommodate a single person. It was the first verified submarine capable of independent underwater operation and movement, the first to use screws for propulsion. In 1800, France built a human-powered submarine designed by the Nautilus; the French gave up on the experiment in 1804, as did the British when they considered Fulton's submarine design. In 1864, late in the American Civil War, the Confederate navy's H. L. Hunley became the first military submarine to sink an enemy vessel, the Union sloop-of-war USS Housatonic. In the aftermath of its successful attack against the ship, the Hunley sank because it was too close to its own exploding torpedo. In 1866, the Sub Marine Explorer was the first submarine to dive, cruise underwater, resurface under the control of the crew; the design by German American Julius H. Kroehl incorporated elements that are still used in modern submarines.
In 1866, the Flach was built at the request of the Chilean government, by Karl Flach, a German engineer and immigrant