A submarine chaser is a small and fast naval vessel, intended for anti-submarine warfare. Many of the American submarine chasers used in World War I found their way to Allied nations by way of Lend-Lease in World War II. U. S. Navy submarine chasers were designed to destroy German submarines in World War I, Japanese and German submarines in World War II; the small 110-foot SC-1-class submarine chasers of the design used in World War I carried the hull designator SC. Their main weapon was the depth charge, they carried machine guns and anti-aircraft guns. The similar-sized SC-497-class was built for World War II. In World War II, larger 173-foot PC-461-class submarine chasers used the PC hull classification symbol. In early 1915, the British Admiralty selected the US Elco company for the production of 50 Motor Launches for anti-submarine work, British industry being at maximum capacity; this order was increased by a further 530. The whole order was completed by November 1916, the vessels entered Royal Navy service.
The vessels were capable of 20 knots. They were armed with a 3-pounder gun, towed paravanes to attack submarines and depth charges. Additional motor launches of the Fairmile A and B and other classes were built for World War II; the British sub chasers were operated around the coast in defence. However, they were uncomfortable and not suited to British sea conditions. Although used during the First World War, they were sold. Submarine chasers were used by the United States Coast Guard in World War II for destroying German U-boats that were stationed off the coast of the United States that were trying to sink merchant convoys as they departed American ports. By the end of World War II, submarine chasers had sunk around 67 German U-boats. In the Pacific Theatre, submarine chasers were used for amphibious landings and escort duty. Eight British Fairmile B Motor Launches were transferred from Canada to the US in World War II, included the SC-1466 class of sub-chasers; the Imperial Japanese Navy had around 250 submarine chasers in World War II, principally about 200 of the No.1-class auxiliary submarine chasers.
Some of these survived to serve in the Japan Maritime Self Defense Force after the war. During Project Hula, the United States secretly transferred 32 U. S. Navy submarine chasers to the Soviet Union between 26 May and 2 September 1945, some of these saw action in the Soviet Navy during Soviet military operations against the Japanese between 9 August and 2 September 1945; the transfer of 24 more was canceled when transfers halted on 5 September 1945, three days after the Japanese surrender. Between 1954 and 1960 all 32 transferred submarine chasers were scrapped by the Soviet Union or destroyed off its coast by mutual agreement between the two countries. In the decade after World War II, the Soviet Union built 227 Kronshtadt-class submarine chasers, some of which remained in active service until the 1990s. Rapid developments in submarine technologies since World War II mean that submarine chasers are now obsolete, having been replaced by corvettes and destroyers; the only remaining submarine chaser with intact World War II armament is the Royal Norwegian Navy's HNoMS Hitra, a touring museum today.
In the Netherlands, there is still afloat PC1610 - a post World War II submarine chaser. The Le Fougueux was built in 1953 from US World War II drawings. List of patrol vessels of the United States Navy List of Escorteurs of the French Navy Motor Launch Harbour Defence Motor Launch Gardiner, Conway's all the world's fighting ships 1906–1921 Conway Maritime Press, 1985. ISBN 0-85177-245-5. Gardiner and Chesneau, Conway's all the world's fighting ships 1922-1946, Conway Maritime Press, 1980. ISBN 0-83170-303-2. Watts, Anthony J. "Japanese Warships of World War II", Doubleday, 1966. ISBN 0-385-09189-3. Subchaser Archives a site dedicated to US World War. Subchasers at Ships of the U. S. Navy, 1940–1945
SC-497-class submarine chaser
The SC-497-class submarine chasers were a class of 438 submarine chasers built for the United States Navy from 1941-1944. The SC-497s were based on the experimental submarine chaser, USS SC-453. Production began in 1941 and continued until they were succeeded by the SC-1466-class submarine chaser in 1944. Submarine chasers of this variety were collectively nicknamed "the splinter fleet" due to their wooden hulls; the SC-497s were off-shore patrol and anti-submarine warfare vessels. Seventy of the SC-497s were converted into patrol control crafts, 18 were converted into coastal minesweepers, 8 were converted into patrol gunboats, motor. Sixteen SC-497s were lost and another one was lost after her conversion into a PGM-1-class motor gunboat. Despite the large number of SC-497s, none are credited with destroying an enemy ship. During World War II, 142 SC-497-class submarine chasers were lent to allies of the United States as part of the Lend-Lease program. Seventy-eight were sent to the Soviet Union, 50 to France, 8 to Brazil, 3 to Norway, 3 to Mexico.
The three Norwegian examples served with distinction on the Shetland bus service, running agents and weapons past the German blockade between occupied Norway and Britain. HNoMS Hitra is preserved at the Royal Norwegian Navy Museum; some remains of HNoMS Hessa and HNoMS Vigra can be seen near the coast of Sweden. List of patrol vessels of the United States Navy
Dorchester is a Boston neighborhood comprising more than 6 square miles in the City of Boston, United States. Dorchester was a separate town, founded by Puritans who emigrated in 1630 from Dorchester, England to the Massachusetts Bay Colony; this dissolved municipality, Boston's largest neighborhood by far, is divided by city planners in order to create two planning areas equivalent in size and population to other Boston neighborhoods. The neighborhood is named after the town of Dorchester in the English county of Dorset, from which Puritans emigrated on the ship Mary and John, among others. Founded in 1630, just a few months before the founding of the city of Boston, Dorchester now covers a geographic area equivalent to nearby Cambridge, it was still a rural town and had a population of 12,000 when it was annexed to Boston in 1870. Railroad and streetcar lines brought rapid growth, increasing the population to 150,000 by 1920. In the 2010 United States Census, the neighborhood's population was 92,115.
The Dorchester neighborhood has a diverse population, which includes a large concentration of African Americans, White Americans, Caribbean Americans and East and Southeast Asian Americans. Dorchester has a significant LGBT population, with active political groups and the largest concentration of same-sex couples in Boston after the South End and Jamaica Plain. Most of the people over the age of 25 have completed high school or obtained a GED. Dorchester was inhabited by the Neponset/Neponsett tribe of the Massachusett nation. For generations, they made their home along the Neponset River estuary, a plentiful source of food due to the freshwater meeting the salt water; the Neponsett "concept of land ownership differed from the European. The Massachusett did not own the land; the Neponsett owned the shellfish beds and trout from the marsh and river. The Massachusett leader, negotiated with the first settlers, but he died of smallpox in 1633, his brother, Cutshamekin deeded further land to the settlers.
Despite several centuries of struggle due to European settlement, members of the Neponsett/Ponkapoag tribe continue to live in the Boston area and have established a tribal council. In 1626 David Thompson settled his family on Thompson Island in what is now Dorchester before Boston's Puritan migration wave began in 1630. May 30, 1630, Captain Squib of the ship Mary and John entered Boston Harbor and on June 17, 1630, landed a boat with eight men on the Dorchester shore, at what was a narrow peninsula known as Mattapan or Mattaponnock, today is known as Columbia Point; those aboard the ship who founded the town included William Phelps, Roger Ludlowe, John Mason, John Maverick, Nicholas Upsall, Capt. Roger Fyler, William Gaylord, Henry Wolcott and other men who would become prominent in the founding of a new nation; the original settlement founded in 1630 was at what is now the intersection of Columbia Road and Massachusetts Avenue.. Most of the early Dorchester settlers came from the West Country of England, some from Dorchester, where the Rev. John White was chief proponent of a Puritan settlement in the New World.
The town, founded was centered on the First Parish Church of Dorchester, which still exists as the Unitarian-Universalist church on Meeting House Hill and is the oldest religious organization in present-day Boston. On October 8, 1633, the first Town Meeting in America was held in Dorchester. Today, each October 8 is celebrated as Town Meeting Day in Massachusetts. Dorchester is the birthplace of the first public elementary school in America, the Mather School, established in 1639; the school still stands as the oldest elementary school in America. In 1634 Israel Stoughton built one of the earliest grist mills in America on the Neponset River, Richard Callicott founded a trading post nearby. In 1649, Puritan missionaries, including John Eliot, began a campaign to convert the Indigenous people in Dorchester to Christianity with the help of Cockenoe and John Sassamon, two Indian servants in Dorchester. Eliot was given land by the town of Dorchester for his mission, where he established a church and school.
The oldest surviving home in the city of Boston, the James Blake House, is located at Edward Everett Square, the historic intersection of Columbia Road, Boston Street, Massachusetts Avenue, a few blocks from the Dorchester Historical Society. The Blake House was constructed in 1661, as was confirmed by dendrochronology in 2007. In 1695, a party was dispatched to found the town of Dorchester, South Carolina, which lasted a half-century before being abandoned. In 1765, chocolate was first introduced in the American colonies when Irish chocolate maker John Hannon imported beans from the West Indies and refined th
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 English Channel called the Channel, is the body of water that separates Southern England from northern France and links the southern part of the North Sea to the Atlantic Ocean. It is the busiest shipping area in the world, it is about 560 km long and varies in width from 240 km at its widest to 33.3 km in the Strait of Dover. It is the smallest of the shallow seas around the continental shelf of Europe, covering an area of some 75,000 km2; until the 18th century, the English Channel had no fixed name either in French. It was never defined as a political border, the names were more or less descriptive, it was not considered as the property of a nation. Before the development of the modern nations, British scholars often referred to it as "Gaulish" and French scholars as "British" or "English"; the name "English Channel" has been used since the early 18th century originating from the designation Engelse Kanaal in Dutch sea maps from the 16th century onwards. In modern Dutch, however, it is known as Het Kanaal.
It has been known as the "British Channel" or the "British Sea". It was called Oceanus Britannicus by the 2nd-century geographer Ptolemy; the same name is used on an Italian map of about 1450, which gives the alternative name of canalites Anglie—possibly the first recorded use of the "Channel" designation. The Anglo-Saxon texts call it Sūð-sǣ as opposed to Norð-sǣ; the common word channel was first recorded in Middle English in the 13th century and was borrowed from Old French chanel, variant form of chenel "canal". The French name la Manche has been in use since at least the 17th century; the name is said to refer to the Channel's sleeve shape. Folk etymology has derived it from a Celtic word meaning channel, the source of the name for the Minch in Scotland, but this name was never mentioned before the 17th century, French and British sources of that time are clear about its etymology; the name in Breton means "Breton Sea", its Cornish name means "British Sea". The International Hydrographic Organization defines the limits of the English Channel as follows: The IHO defines the southwestern limit of the North Sea as "a line joining the Walde Lighthouse and Leathercoat Point".
The Walde Lighthouse is 6 km east of Calais, Leathercoat Point is at the north end of St Margaret's Bay, Kent. The Strait of Dover, at the Channel's eastern end, is its narrowest point, while its widest point lies between Lyme Bay and the Gulf of Saint Malo, near its midpoint, it is shallow, with an average depth of about 120 m at its widest part, reducing to a depth of about 45 m between Dover and Calais. Eastwards from there the adjoining North Sea reduces to about 26 m in the Broad Fourteens where it lies over the watershed of the former land bridge between East Anglia and the Low Countries, it reaches a maximum depth of 180 m in the submerged valley of Hurd's Deep, 48 km west-northwest of Guernsey. The eastern region along the French coast between Cherbourg and the mouth of the Seine river at Le Havre is referred to as the Bay of the Seine. There are several major islands in the Channel, the most notable being the Isle of Wight off the English coast, the Channel Islands, British Crown dependencies off the coast of France.
The coastline on the French shore, is indented. The Cotentin Peninsula in France juts out into the Channel, whilst on the English side there is a small parallel strait known as the Solent between the Isle of Wight and the mainland; the Celtic Sea is to the west of the Channel. The Channel acts as a funnel that amplifies the tidal range from less than a metre as observed at sea to more than 6 metres as observed in the Channel Islands, the west coast of the Cotentin Peninsula and the north coast of Brittany; the time difference of about six hours between high water at the eastern and western limits of the Channel is indicative of the tidal range being amplified further by resonance. In the UK Shipping Forecast the Channel is divided into the following areas, from the east: Dover Wight Portland Plymouth The Channel is of geologically recent origin, having been dry land for most of the Pleistocene period. Before the Devensian glaciation and Ireland were part of continental Europe, linked by an unbroken Weald-Artois Anticline, a ridge that acted as a natural dam holding back a large freshwater pro-glacial lake in the Doggerland region, now submerged under the North Sea.
During this period the North Sea and all of the British Isles were covered by ice. The lake was fed by meltwater from the Baltic and from the Caledonian and Scandinavian ice sheets that joined to the north, blocking its exit; the sea level was about 120 m lower. Between 450,000 and 180,000 years ago, at least two catastrophic glacial lake outburst floods breached the Weald–Artois anticline; the first flood would have lasted for several months, releasing as much as one million cubic metres of water per second. The flood started with large but localized waterfalls over the ridge, which excav
Portsmouth is a port city in Hampshire, with a total population of 205,400 residents. The city of Portsmouth is nicknamed Pompey and is built on Portsea Island, a flat, low-lying island measuring 24 square kilometres in area, just off the south-east coast of Hampshire. Uniquely, Portsmouth is the only island city in the United Kingdom, is the only city whose population density exceeds that of London. Portsmouth is located 70 miles south-west of London and 19 miles south-east of Southampton. With the surrounding towns of Gosport, Fareham and Waterlooville, Portsmouth forms the eastern half of the South Hampshire metropolitan area, which includes Southampton and Eastleigh in the western half. Portsmouth's history can be traced back to Roman times. A significant naval port for centuries, Portsmouth has the world's oldest dry dock. In the sixteenth century, Portsmouth was England's first line of defence during the French invasion of 1545. By the early nineteenth century, the world's first mass production line was set up in Portsmouth Dockyard's Block Mills, making it the most industrialised site in the world and birthplace of the Industrial Revolution.
Portsmouth was the most fortified town in the world, was considered "the world's greatest naval port" at the height of the British Empire throughout Pax Britannica. Defences known as the Palmerston Forts were built around Portsmouth in 1859 in anticipation of another invasion from continental Europe. In 1926, Portsmouth was elevated in status from a town to a city; the motto "Heaven's Light Our Guide" was registered to the City of Portsmouth in 1929. During the Second World War, the city of Portsmouth was a pivotal embarkation point for the D-Day landings and was bombed extensively in the Portsmouth Blitz, which resulted in the deaths of 930 people. In 1982, a large proportion of the task force dispatched to liberate the Falkland Islands deployed from the city's naval base, her Majesty's Yacht Britannia left the city to oversee the transfer of Hong Kong in 1997, which marked for many the end of the empire. In 1997, Portsmouth became a Unitary Authority, with Portsmouth City Council gaining powers of a non-metropolitan county and district council combined, responsibilities held by Hampshire County Council.
Portsmouth is one of the world's best known ports. HMNB Portsmouth is considered to be the home of the Royal Navy and is home to two-thirds of the UK's surface fleet; the city is home to some famous ships, including HMS Warrior, the Tudor carrack Mary Rose and Horatio Nelson's flagship, HMS Victory. The former HMS Vernon naval shore establishment has been redeveloped as a retail park known as Gunwharf Quays. Portsmouth is among the few British cities with two cathedrals: the Anglican Cathedral of St Thomas and the Roman Catholic Cathedral of St John the Evangelist; the waterfront and Portsmouth Harbour are dominated by the Spinnaker Tower, one of the United Kingdom's tallest structures at 560 feet. Nearby Southsea is a seaside resort with a pier amusement medieval castle. Portsmouth F. C. the city's professional football club, play their home games at Fratton Park. The city has several mainline railway stations that connect to Brighton, London Victoria and London Waterloo amongst other lines in southern England.
Portsmouth International Port is a commercial cruise ship and ferry port for international destinations. The port is the second busiest in the United Kingdom after Dover, handling around three million passengers a year; the city had its own airport, Portsmouth Airport, until its closure in 1973. The University of Portsmouth enrols 23,000 students and is ranked among the world's best modern universities. Portsmouth is the birthplace of author Charles Dickens and engineer Isambard Kingdom Brunel; the Romans built a fort, at nearby Portchester in the late third century. The city's Old English name "Portesmuða" is derived from port, meaning a haven, muða, the mouth of a large river or estuary; the Anglo-Saxon Chronicle has a warrior called Port and his two sons killing a noble Briton in Portsmouth in 501. Winston Churchill, in his A History of the English-Speaking Peoples, says that Port was a pirate and he founded Portsmouth in 501; the south coast was vulnerable to Danish Viking invasions during the 9th centuries.
In 787, it was assaulted and conquered by Danish pirates, during the reign of Æthelwulf, King of Wessex in 838, a Danish fleet landed between Portsmouth and Southampton and the surrounding area was plundered. In response, Æthelwulf sent Wulfherd and the governor of Dorsetshire to confront the Danes at Portsmouth, where most of their ships were docked, they were successful. In 1001, the Danes returned and pillaged Portsmouth and surrounding locations, threatening the English with extinction; the Danes were massacred by the survivors the following year and rebuilding began, although the town suffered further attacks until 1066. Portsmouth was not mentioned in the Domesday Survey of 1086, but Bocheland and Frodentone were; some sources maintain. When King Henry II died in 1189, his son Richard I, who had spent most of his life in France, arrived in Portsmouth before he was crowned in London; when Richard returned from captivity in Austria in May 1194, he summoned a fleet of 100 ships and an army to the port.
He granted the town a royal charter on 2 May, giving permission for an annual fifteen-day free market fair, weekly markets, a local court to deal with minor matters, exempted its inhabitants from paying an annual tax of £18. Richard granted the town the arm