Swinbrook is a village on the River Windrush, about 2 miles east of Burford in Oxfordshire, England. The village is in the civil parish of Widford. Widford is a hamlet about 0.5 miles west of Swinbrook. The 2011 Census recorded Swinbrook and Widford's parish population as 139; the Church of England parish church of Saint Mary the Virgin dates from about 1200. Its unusual open-sided bell-tower was added in 1822; the church is noted for its 17th-century Fettiplace monuments. David Freeman-Mitford, 2nd Baron Redesdale had Swinbrook House built 1.5 miles north of the village. Four of his six daughters are buried in the parish churchyard: Nancy and Diana are buried side by side, while Pamela is buried northwest of the tower. There is a tablet in the church commemorating their only brother, killed in March 1945 in Burma. St Mary's has a monument to the officers and men of the Royal Navy submarine HMS P514, its commander, Lieutenant W. A. Phillimore, whose parents lived at Swinbrook. In 1942 P514 failed to identify herself to the Royal Canadian Navy minesweeper HMCS Georgian.
The Canadian ship therefore assumed the submarine to be an enemy vessel and rammed P514, sinking her with the loss of all hands. Swinbrook Cricket Club has two teams, they play in division 5 and 10 of the Oxfordshire Cricket Association. Case, Humphrey. "Swinbrook, Oxon". Oxoniensia. Oxford Architectural and Historical Society. XXIII: 138. Hinton, David A.. "Medieval Pottery from Swinbrook, Oxon". Oxoniensia. Oxford Architectural and Historical Society. XXXVI: 107–110. Ottewell, Gordon. Literary strolls around the Forest of Dean. Wilmslow: Sigma Leisure. P. 71. ISBN 1-85058-687-X. Pearson, Lynn F. Discovering Famous Graves. Oxford: Shire Publications. P. 93. ISBN 0747806195. Sherwood, Jennifer. Oxfordshire; the Buildings of England. Harmondsworth: Penguin Books. Pp. 799–800. ISBN 0-14-071045-0. Media related to Swinbrook at Wikimedia Commons Google 360° panorama of the chancel of St Mary the Virgin parish church, showing the Fettiplace monuments
A reserve fleet is a collection of naval vessels of all types that are equipped for service but are not needed, thus or decommissioned. A reserve fleet is informally said to be "in mothballs" or "mothballed". S. naval usage is "ghost fleet". In earlier times, in British usage, these ships were said to be laid up in ordinary; such ships are held in reserve against a time when it may be necessary to call them back into service, they are tied up in backwater areas near naval bases or shipyards to speed the reactivation process. They may be modified, for instance by having rust-prone areas sealed off or wrapped in plastic or, in the case of sailing warships, the masts removed. While being held in the reserve fleet, ships have a minimal crew to ensure that they stay in somewhat usable condition. If for nothing else, their bilge pumps need to be run to reduce corrosion of their steel and to prevent the ships from foundering at their moorings; when a ship is placed into reserve status, the various parts and weapon systems that the ship uses are placed in a storage facility, so that if the warship is reactivated, the proper spare parts and ammunition are available, but like the ships themselves, the stored parts and equipment are prone to fall into disrepair, suffer metal corrosion, become obsolete.
The British Reserve Fleet was a repository for British decommissioned warships from c. 1800 until c. 1970. The United States National Defense Reserve Fleet, consists of about fifty World War II ships that have been moored in Suisun Bay near San Francisco since the 1950s or'60s; the fleet includes military tankers. In practice most reserve ships become obsolete and are scrapped, or used for experiments or target practice, or are sold to other nations, or become museum ships or artificial reefs. Exporting the vessels for shipbreaking or dismantling are alternatives to reserve fleets. More the U. S. Navy has established a program to allow ships, such as Oriskany, to be sunk in selected locations to create artificial reefs. Recycling is another option, as in the case of the United States National Defense Reserve Fleet, the ships of which are set to be stripped of their paint, cut into pieces, recycled. Steel from pre-nuclear age ships either mothballed or sunk and raised, called low-background steel, is used in experimental physics when the experiment requires shielding material, itself only weakly radioactive, emitting less than present-day background radiation.
The practice of exporting and dismantling ships has caused international protests as they contain toxic materials. In 2007, following studies that found that 20 tons of lead paint had flaked off the ships of the NDRF, environmentalist groups sued to have them removed; the U. S. Federal Maritime Administration agreed to remove more than 50 of the ships as a result, 25 of which have been removed by 2012 and the remainder removed at the end of 2017. Aircraft boneyard National Defense Reserve Fleet Suisun Bay Reserve Fleet United States Navy reserve fleets Daniel Madsen. Forgotten Fleet; the Mothball Navy. U. S. Naval Institute Press. 1999. To Sail No More. Seven volumes. Maritime Books. United Kingdom. P. W. Singer and August Cole. Ghost Fleet. Mariner Books, Houghton Mifflin Harcourt. 2015
Delaware Bay is the estuary outlet of the Delaware River on the Northeast seaboard of the United States. 782 square miles in area, the bay's fresh water mixes for many miles with the salt water of the Atlantic Ocean. The bay is bordered inland by the States of New Jersey and Delaware, the Delaware Capes, Cape Henlopen and Cape May, on the Atlantic; the Delaware Bay is bordered by six counties: Sussex and New Castle in Delaware, along with Cape May and Salem in New Jersey. The Cape May–Lewes Ferry crosses the Delaware Bay from Cape May, New Jersey, to Lewes, Delaware. Management of ports along the bay is the responsibility of the Delaware Bay Authority; the shores of the bay are composed of salt marshes and mudflats, with only small communities inhabiting the shore of the lower bay. Besides the Delaware, it is fed by numerous smaller rivers and streams, including the Christina River, Appoquinimink River, Leipsic River, Smyrna River, St. Jones River, Murderkill Rivers on the Delaware side, the Salem River, Cohansey River, Maurice Rivers on the New Jersey side.
Several of the rivers hold protected status for their salt marsh wetlands bordering the bay, which serves as a breeding ground for many aquatic species, including horseshoe crabs. The bay is a prime oystering ground; the Delaware Bay was designated a Ramsar Wetland of International Importance on May 20, 1992. It was the first site classified in the Western Hemisphere Shorebird Reserve Network. At the time of the arrival of the Europeans in the early 17th century, the area around the bay was inhabited by the Native American Lenape people, they called the Delaware River "Lenape Wihittuck", which means "the rapid stream of the Lenape". The Delaware Bay was called "Poutaxat", which means "near the falls". In 1523 Lucas Vázquez de Ayllón had received from Charles V, Holy Roman Emperor a grant for the land explored in 1521 by Francisco Gordillo and slave trader Captain Pedro de Quejo. In 1525 Ayllón sent Quejo northward and received reports of the coastline from as far north as the Delaware Bay. In 1525 De Ayllon and Captain Quejo called Delaware Bay by the name Saint Christopher's Bay.
In the 1600s the bay was known as "Niew Port May" after Captain Cornelius May. Another recorded European visit to the bay was by Henry Hudson, who claimed it for the Dutch East India Company in 1609; the Dutch called the estuary "Godyns Bay", or "Godins Bay" after a director of the company, Samuel Godijn. As part of the New Netherland colony, the Dutch established several settlements on the shores of the bay and explored its coast extensively; the thin nature of the corporate colony's presence in the bay and along what was called the South River made it possible for Peter Minuit, the former director of New Netherland, to establish a competing Swedish sponsored settlement, New Sweden in 1638. The resulting dispute with the Dutch colonial authorities in New Amsterdam was settled when Petrus Stuyvesant led a Dutch military force into the area in 1655. After the English took title to the New Netherland colony in 1667 at the Treaty of Breda the bay came into their possession and was renamed, by Samuel Argall, the river Delaware, after the first Governor of Virginia Thomas West, 3rd Baron De La Warr.
The Native American tribe living along the bay and river were called the Delaware by the Europeans due to their location. The U. S. state takes its name from the bay and the river. Conflicting crown grants were made to the James, Duke of York and William Penn on the west bank of the bay and river. Settlement grew leading Philadelphia, upriver on the Delaware, to become the largest city in North America in the 18th century. Penn viewed access to the Delaware Bay as being so critical to Pennsylvania's survival that he engaged in an eighty-year long legal boundary dispute with the Calvert family to secure it. In 1782 during the American Revolutionary War, Continental Navy Lieutenant Joshua Barney fought with a British squadron within the bay. Barney's force of three sloops defeated a Royal Navy frigate, a sloop-of-war and a Loyalist privateer; the strategic importance of the bay was noticed by the Marquis de Lafayette during the American Revolutionary War, who proposed the use of Pea Patch Island at the head of the bay for a defensive fortification to protect the important ports Philadelphia and New Castle, Delaware.
Fort Delaware was constructed on Pea Patch Island. During the American Civil War it was used as a Union prison camp. In 1855, the United States government systematically undertook the formation of a 26 ft channel 600 ft wide from Philadelphia to deep water in Delaware Bay; the Rivers and Harbors Act of 1899 provided for a 30-foot channel 600 feet wide from Philadelphia to the deep water of the bay. Other names for the bay have been "South Bay" and "Zuyt Baye"; the bay is one of the most important navigational channels in the United States. Its lower course forms part of the Intracoastal Waterway; the need for direct navigation around the two capes into the ocean is circumvented by the Cape May Canal and the Lewes and Rehoboth Canal at the north and south capes respectively. The upper bay is connected directly to the north end of Chesapeake Bay by the Chesapeake and Delaware Canal; the bay offers several challenges to mariners: a significant current of up to three knots, which builds a nasty chop when the wind is in opposition.
Partnership for the Delaware Estuary Lewes and Rehoboth Canal Chesapeake and Delaware Canal B
A torpedo tube is a cylinder shaped device for launching torpedoes. There are two main types of torpedo tube: underwater tubes fitted to submarines and some surface ships, deck-mounted units installed aboard surface vessels. Deck-mounted torpedo launchers are designed for a specific type of torpedo, while submarine torpedo tubes are general-purpose launchers, are also capable of deploying mines and cruise missiles. Most modern launchers are standardised on a 12.75-inch diameter for light torpedoes or a 21-inch diameter for heavy torpedoes, although other sizes of torpedo tube have been used: see Torpedo classes and diameters. A submarine torpedo tube is a more complex mechanism than a torpedo tube on a surface ship, because the tube has to accomplish the function of moving the torpedo from the normal atmospheric pressure within the submarine into the sea at the ambient pressure of the water around the submarine, 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 does show the working of a submarine torpedo launch. A torpedo tube has a considerable number of interlocks for safety reasons. For example, an interlock prevents the breech 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 wire-guide 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. Flood the torpedo tube; this may be done manually or automatically, from sea or from tanks, depending on the class of submarine. The tube must be vented during this process to allow for complete filling and eliminate air pockets which could escape to the surface or cause damage when firing. Open the equalizing valve to equalize pressure in the tube with ambient sea pressure. Open the muzzle door. 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 ejection pump to enter the tube; when the launch command is given and all interlocks are satisfied, the water ram operates, thrusting a large volume of water into the tube at high pressure, which ejects the torpedo from the tube with considerable force. 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 guidance 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 start outside the tube. Once outside the tube the torpedo begins its run toward the target as programmed by the fire control system. Attack functions are programmed but with wire guided weapons, certain functions can be controlled from the ship.
For wire-guided torpedoes, the muzzle door must remain open because the guidance wire is still connected to the inside of the breech door to receive commands from the submarine's fire-control system. A wire cutter on the inside of the breech door is activated to release the wire and its protective cable; these are drawn clear of the ship prior to shutting the muzzle door. The drain cycle is a reverse of the flood cycle. Water can be moved as necessary; the tube must be vented to drain the tube since it is by gravity. Open the breech door and remove the remnants of the torpedo power cable and the guidance wire basket; the tube must be wiped dry to prevent a buildup of slime. This process is called "diving the tube" and tradition dictates that "ye who shoots, dives". Shut and lock the breech door. Spare torpedoes are stored behind the tube in racks. Speed is a desirable feature of a torpedo loading system. There are various manual and hydraulic handling systems for loading torpedoes into the tubes. Prior to the Ohio class, US SSBNs utilized manual block and tackle which took about 15 minutes to load a tube.
SSNs prior to the Seawolf class used a hydraulic system, much faster and safer in conditions where the ship needed to maneuver. The German Type 212 submarine uses a new development of the water ram expulsion system, which ejects the torpedo with water pressure to avoid acoustic detection. List of torpedoes by diameter The Fleet Type Submarine Online 21-Inch Submerged Torpedo Tubes United States Navy Restricted Ordnance Pamphlet 1085, June 1944 Torpedo tubes of German U-Boats
Ceremonial ship launching
Ceremonial ship launching is the process of transferring a vessel to the water. It is a naval tradition in many cultures, it has been observed as a solemn blessing. Ship launching imposes stresses on the ship not met during normal operation, in addition to the size and weight of the vessel, it represents a considerable engineering challenge as well as a public spectacle; the process involves many traditions intended to invite good luck, such as christening by breaking a sacrificial bottle of champagne over the bow as the ship is named aloud and launched. There are three principal methods of conveying a new ship from building site to water, only two of which are called "launching"; the oldest, most familiar, most used is the end-on launch, in which the vessel slides down an inclined slipway stern first. With the side launch, the ship enters the water broadside; this method came into use in the 19th-century on inland waters and lakes, was more adopted during World War II. The third method is float-out, used for ships that are built in basins or dry docks and floated by admitting water into the dock.
If launched in a restrictive waterway drag chains are used to slow the ship speed to prevent it striking the opposite bank. Ways are arranged perpendicular to the shore line and the ship is built with its stern facing the water. Where the launch takes place into a narrow river, the building slips may be at a shallow angle rather than perpendicular though this requires a longer slipway when launching. Modern slipways take the form of a reinforced concrete mat of sufficient strength to support the vessel, with two "barricades" that extend well below the water level taking into account tidal variations; the barricades support the two launch ways. The vessel is built upon temporary cribbing, arranged to give access to the hull's outer bottom and to allow the launchways to be erected under the complete hull; when it is time to prepare for launching, a pair of standing ways is erected under the hull and out onto the barricades. The surface of the ways is greased. A pair of sliding ways is placed on top, under the hull, a launch cradle with bow and stern poppets is erected on these sliding ways.
The weight of the hull is transferred from the build cribbing onto the launch cradle. Provision is made to hold the vessel in place and release it at the appropriate moment in the launching ceremony. On launching, the vessel slides backwards down the slipway on the ways; some slipways is launched sideways. This is done where the limitations of the water channel would not allow lengthwise launching, but occupies a much greater length of shore; the Great Eastern designed by Brunel was built this way as were many landing craft during World War II. This method requires many more sets of ways to support the weight of the ship. Sometimes ships are launched using a series of inflated tubes underneath the hull, which deflate to cause a downward slope into the water; this procedure has the advantages of requiring less permanent infrastructure and cost. The airbags provide support to the hull of the ship and aid its launching motion into the water, thus this method is arguably safer than other options such as sideways launching.
These airbags are cylindrical in shape with hemispherical heads at both ends. The Xiao Qinghe shipyard launched a tank barge with marine airbags on January 20, 1981, the first known use of marine airbags. A Babylonian narrative dating from the 3rd millennium BC describes the completion of a ship: Openings to the water I stopped. Egyptians and Romans called on their gods to protect seamen. Favor was evoked from the monarch of the seas—Poseidon in Greek mythology, Neptune in Roman mythology. Ship launching participants in ancient Greece wreathed their heads with olive branches, drank wine to honor the gods, poured water on the new vessel as a symbol of blessing. Shrines were carried on board Greek and Roman ships, this practice extended into the Middle Ages; the shrine was placed at the quarterdeck, an area which continues to have special ceremonial significance. Different peoples and cultures shaped the religious ceremonies surrounding a ship launching. Jews and Christians customarily used wine and water as they called upon God to safeguard them at sea.
Intercession of the saints and the blessing of the church were asked by Christians. Ship launchings in the Ottoman Empire were accompanied by prayers to Allah, the sacrifice of sheep, appropriate feasting. Chaplain Henry Teonge of Britain's Royal Navy left an interesting account of a warship launch, a "briganteen of 23 oars," by the Knights of Malta in 1675: Two friars and an attendant went into the vessel, kneeling down prayed halfe an houre, layd their hands on every mast, other places of the vessel, sprinkled her all over with holy water, they came out and hoysted a pendent to signify she was a man of war. The liturgical aspects of ship christenings, or baptisms, continued in Catholic countries, while the Reformation seems to have put a stop to them for a time in Protestant Europe. By the 17th century, for example, English launchings were secular affairs; the christening party for the launch of the
A minesweeper is a small naval warship designed to engage in minesweeping. Using various mechanisms intended to counter the threat posed by naval mines, waterways are kept clear for safe shipping. Although naval warfare has a long history, the earliest known usage of the naval mine dates to the Ming dynasty. Dedicated minesweepers, only appear in the historical record several centuries to the Crimean War, where they were deployed by the British. In the Crimean War, minesweepers consisted of British rowboats trailing grapnels to snag the mines. Despite the use of mines in the American Civil War, there are no records of effective minesweeping being used. Officials in the Union Army attempted to create the first minesweeper but were plagued by flawed designs and abandoned the project. Minesweeping technology picked up in the Russo-Japanese War, using aging torpedo boats as minesweepers. In Britain, naval leaders recognized before the outbreak of World War I that the development of sea mines was a threat to the nation's shipping and began efforts to counter the threat.
Sir Arthur Wilson noted the real threat of the time was blockade aided by not invasion. The function of the fishing fleet's trawlers with their trawl gear was recognized as having a natural connection with mine clearance and, among other things, trawlers were used to keep the English Channel clear of mines. A Trawler Section of the Royal Navy Reserve became the predecessor of the mine sweeping forces with specially designed ships and equipment to follow; these reserve Trawler Section fishermen and their trawlers were activated, supplied with mine gear, rifles and pay as the first minesweepers. The dedicated, purpose-built minesweeper first appeared during World War I with the Flower-class minesweeping sloop. By the end of the War, naval mine technology had grown beyond the ability of minesweepers to detect and remove. Minesweeping made significant advancements during World War II. Combatant nations adapted ships to the task of minesweeping, including Australia's 35 civilian ships that became Auxiliary Minesweepers.
Both Allied and Axis countries made heavy use of minesweepers throughout the war. Historian Gordon Williamson wrote that "Germany's minesweepers alone formed a massive proportion of its total strength, are much the unsung heroes of the Kriegsmarine." Naval mines remained a threat after the war ended, minesweeping crews were still active after VJ Day. After the Second World War, allied countries worked on new classes of minesweepers ranging from 120-ton designs for clearing estuaries to 735-ton oceangoing vessels; the United States Navy used specialized Mechanized Landing Craft to sweep shallow harbors in and around North Korea. As of June 2012, the U. S. Navy had four minesweepers deployed to the Persian Gulf to address regional instabilities. Minesweepers are equipped with mechanical or electrical devices, known as "sweeps", for disabling mines; the modern minesweeper is designed to reduce the chances of it detonating mines itself. Mechanical sweeps are devices designed to cut the anchoring cables of moored mines, preferably attach a tag to help the subsequent localization and neutralization.
They are towed behind the minesweeper, use a towed body to maintain the sweep at the desired depth and position. Influence sweeps are equipment towed, that emulate a particular ship signature, thereby causing a mine to detonate; the most common such sweeps are acoustic generators. There are two modes of operating an influence sweep: MSM and TSM. MSM sweeping is founded on intelligence on a given type of mine, produces the output required for detonation of this mine. If such intelligence is unavailable, the TSM sweeping instead reproduces the influence of the friendly ship, about to transit the area. TSM sweeping thus clears. However, mines directed at other ships might remain; the minesweeper differs from a minehunter. Minesweepers are in many cases complementary to minehunters, depending on the operation and the environment. Both kinds of ships are collectively called mine countermeasure vessels, a term applied to a vessel that combines both roles; the first such ship was HMS Wilton the first warship to be constructed from fiberglass.
HNLMS Abraham Crijnssen – famous for her escape from Surabaya in 1942 disguised as a tropical island HMS Bronington – commanded by HRH Prince Charles, Prince of Wales Calypso – research vessel of Jacques-Yves Cousteau. Now converted to a yacht club's club house and moored on the foreshore between Leigh-on-Sea and Westcliff in Essex, England USS Lucid – The last surviving U. S. Navy MSO hull, it is in process of being restored as a museum USS Guardian – Grounded on a reef in the Philippines in 2013. HMCS Bras d'Or – Royal Canadian Navy minesweeper lost in the Gulf of St. Lawrence. Boltenhagen and Pasewalk, East German minesweepers purchased by Malta and used as patrol boats P29 and P31 and sunk as diving sites in 2007 and 2009. List of minesweeper classes Minehunter Demining Naval Mine List of mine warfare vessels of the United States Navy List of mine countermeasure vessels of the Royal Navy List of mine warfare vess
A shipyard is a place where ships are built and repaired. These can be military vessels, cruise liners or other cargo or passenger ships. Dockyards are sometimes more associated with maintenance and basing activities than shipyards, which are sometimes associated more with initial construction; the terms are used interchangeably, in part because the evolution of dockyards and shipyards has caused them to change or merge roles. Countries with large shipbuilding industries include Australia, China, Denmark, France, India, Italy, the Netherlands, the Philippines, Romania, Singapore, South Korea, Taiwan, the United Kingdom, Vietnam; the shipbuilding industry is more fragmented in Europe than in Asia where countries tend to have fewer, larger companies. Many naval vessels are built or maintained in shipyards owned or operated by the national government or navy. Shipyards are constructed near tidal rivers to allow easy access for their ships; the United Kingdom, for example, has shipyards on many of its rivers.
The site of a large shipyard will contain many specialised cranes, dry docks, dust-free warehouses, painting facilities and large areas for fabrication of the ships. After a ship's useful life is over, it makes its final voyage to a shipbreaking yard on a beach in South Asia. Shipbreaking was carried on in drydock in developed countries, but high wages and environmental regulations have resulted in movement of the industry to developing regions. Welding, sandblasting and other maintenance work contribute pollution. Ship hulls have many layers of anti-fouling and anti-corrosion paint. Shipyards around the world paint ships by airtight spraying or by thermal spraying. Studies have shown that painting generates half of the dangerous waste at a shipyard due to using high-pressure equipment to wash or remove any unwanted material, on it like rust; this material will make its way to the water as water pollution. In a study in 2011 samples of sediments were collected from two sites in coastal marine area of Yongho Bay, one from the shipyard and the other 500m away.
Both samples contained metals that included Al, Fe, Li, V, Cr, Mn, Ni, Cu, Zn, As, Cd, Sn, Pb. In addition, it had been confirmed that the concentration was higher in the first sample, by the shipyard the sample taking 500m away and was due to paint fragments applied to the steel ship hulls. After a ship has been used it is scrapped at a shipyard, but the process can release excessive amounts of pollution. Paints used for hulls are anti-fouling paints. Over time weathering from ships will sink to the bottom of the seabed and the most common component, toxic in paint used in shipyards is triphenyl tetrazolium and can be treated by using dolomitic sorbents. In 2005, a study showed the high level of toxicity of TBT compounds to organisms in the ocean and what can be done to reduce the pollution by using dolomitic sorbents. In the study, a sample of shipyard water was used in the experiment in a period over 14 days. At the end the experiment it was concluded that dolomitic and dolomite were successful in reducing the contaminants from the shipyard wastewater.
Welding is the most important factor in ship building and should be performed by qualified welders in order to protect the ship structure. It is achieved by heating the surfaces to the point of melting using oxy-acetylene, electric arc, or other means, uniting them by pressing, etc, but in shipyards, there are times when the welder weld. Welding can produce toxic fumes such as Nitric Oxide, Nitrogen Dioxide, Carbon Monoxide, Hydrogen Fluoride, Carbon Dioxide can result in serious damage to human health or death if ventilation is not present. A case study was performed to see where would be most effective place to exhaust the hull cells on the bulkhead in between two spaces using an air horn versus air with an electric blower, they asked them to weld in a specific space. One that had shipyard dilution ventilation and the other had local exhaust ventilation recorded to see which typed of ventilation worked the best. In the results, they found that local exhaust ventilation reduced particulate concentrations but the efficiency of either method depended on equipment maintenance and their own work practices because everyone has a different way of getting things done.
The world's earliest known dockyards were built in the Harappan port city of Lothal circa 2600 BC in Gujarat, India. Lothal's dockyards connected to an ancient course of the Sabarmati river on the trade route between Harappan cities in Sindh and the peninsula of Saurashtra when the surrounding Kutch desert was a part of the Arabian Sea. Lothal engineers accorded high priority to the creation of a dockyard and a warehouse to serve the purposes of naval trade; the dock was built on the eastern flank of the town, is regarded by archaeologists as an engineering feat of the highest order. It was located away from the main current of the river to avoid silting, but provided access to ships in high tide as well; the name of the ancient Greek city of Naupactus means "shipyard". Naupactus' reputation in this field extends to the time of legend, where it is depicted as the place where the Heraclidae built a fleet to invade the Peloponnesus. In the Spanish city of Barcelona, the Drassanes shipyards were active from at least the mid-13th century until the 18th century, although i