In metalworking, rolling is a metal forming process in which metal stock is passed through one or more pairs of rolls to reduce the thickness and to make the thickness uniform. The concept is similar to the rolling of dough. Rolling is classified according to the temperature of the metal rolled. If the temperature of the metal is above its recrystallization temperature the process is known as hot rolling. If the temperature of the metal is below its recrystallization temperature, the process is known as cold rolling. In terms of usage, hot rolling processes more tonnage than any other manufacturing process, cold rolling processes the most tonnage out of all cold working processes. Roll stands holding pairs of rolls are grouped together into rolling mills that can process metal steel, into products such as structural steel, bar stock, rails. Most steel mills have rolling mill divisions that convert the semi-finished casting products into finished products. There are many types of rolling processes, including ring rolling, roll bending, roll forming, profile rolling, controlled rolling.
The invention of the rolling mill in Europe may be attributed to Leonardo da Vinci in his drawings. The earliest rolling mills in crude form but the same basic principles were found in Middle East and South Asia as early as 600 BCE. Earliest rolling mills were slitting mills, which were introduced from what is now Belgium to England in 1590; these passed flat bars between rolls to form a plate of iron, passed between grooved rolls to produce rods of iron. The first experiments at rolling iron for tinplate took place about 1670. In 1697, Major John Hanbury erected a mill at Pontypool to roll'Pontypool plates'—blackplate; this began to be rerolled and tinned to make tinplate. The earlier production of plate iron in Europe had been in forges, not rolling mills; the slitting mill was adapted to producing hoops and iron with a half-round or other sections by means that were the subject of two patents of c. 1679. Some of the earliest literature on rolling mills can be traced back to Christopher Polhem in 1761 in Patriotista Testamente, where he mentions rolling mills for both plate and bar iron.
He explains how rolling mills can save on time and labor because a rolling mill can produce 10 to 20 or more bars at the same time. A patent was granted to Thomas Blockley of England in 1759 for the rolling of metals. Another patent was granted in 1766 to Richard Ford of England for the first tandem mill. A tandem mill is one. Rolling mills for lead seem to have existed by the late 17th century. Copper and brass were rolled by the late 18th century. Modern rolling practice can be attributed to the pioneering efforts of Henry Cort of Funtley Iron Mills, near Fareham, England. In 1783, a patent was issued to Henry Cort for his use of grooved rolls for rolling iron bars. With this new design, mills were able to produce 15 times more output per day than with a hammer. Although Cort was not the first to use grooved rolls, he was the first to combine the use of many of the best features of various ironmaking and shaping processes known at the time, thus modern writers have called him "father of modern rolling."
The first rail rolling mill was established by John Birkenshaw in 1820, where he produced fish bellied wrought iron rails in lengths of 15 to 18 feet. With the advancement of technology in rolling mills, the size of rolling mills grew along with the size of the products being rolled. One example of this was at The Great Exhibition in 1851, where a plate 20 feet long, 3 ½ feet wide, 7/16 of an inch thick, weighing 1,125 pounds, was exhibited by the Consett Iron Company. Further evolution of the rolling mill came with the introduction of three-high mills in 1853 used for rolling heavy sections. Hot rolling is a metalworking process that occurs above the recrystallization temperature of the material. After the grains deform during processing, they recrystallize, which maintains an equiaxed microstructure and prevents the metal from work hardening; the starting material is large pieces of metal, like semi-finished casting products, such as slabs and billets. If these products came from a continuous casting operation the products are fed directly into the rolling mills at the proper temperature.
In smaller operations, the material must be heated. This is done in a gas- or oil-fired soaking pit for larger workpieces; as the material is worked, the temperature must be monitored to make sure it remains above the recrystallization temperature. To maintain a safety factor a finishing temperature is defined above the recrystallization temperature. If the temperature does drop below this temperature the material must be re-heated before more hot rolling. Hot-rolled metals have little directionality in their mechanical properties and deformation induced residual stresses. However, in certain instances non-metallic inclusions will impart some directionality and workpieces less than 20 mm thick have some directional properties. Non-uniform cooling will induce a lot of residual stresses, which occurs in shapes that have a non-uniform cross-section, such as I-beams. While the finished product is of good quality, the surface is covered in mill scale, an oxide that forms at high temperatures, it is removed via pickling or the smooth clean surface process, which reveals a smooth surface.
Dimensional tolerances are us
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
Packet boats were medium-sized boats designed for domestic mail and freight transportation in European countries and their colonies, including North American rivers and canals. They were used extensively during the 18th and 19th centuries and featured scheduled service; when such ships were put into use in the 18th century on the Atlantic Ocean between Great Britain and its colonies, the services were called the packet trade. Packet craft were used extensively in European coastal mail services since the 17th century, added cramped passenger accommodation; as early as 1629, the Dutch East India Company was carrying some passengers on the ill-fated Batavia from Texel in Holland to Java. Scheduled services were offered, but the time journeys took depended much on the weather, they are found to be a subject of Daniel Defoe's 1724 novel Roxana: The Fortunate Mistress. In England the King maintained a weekly packet service with the continent and Ireland using 15 packet vessels, their importance is evident from the fact that the first craft built in the colony of New South Wales was the Rose Hill Packet.
Over the two centuries of the sailing packet craft development, they came in various rig configurations which included: schooners, schooners-brigs, cutters, brigantines, feluccas, xebecs and their ultimate development in the clipper ships. Earlier they were known as dispatch boats, but the service was provided by privateers during time of war, on occasion chartered private yachts. News of "record passages" was eagerly awaited by the public, the craft's captain and crew were celebrated in the press. Behind this search for sailing faster than the wind however lay the foundations for a development in naval architecture and its science which would serve until the appearance of the steam vessels. In 1863, during the Civil War, the packet boat Marshall carried the body of Confederate General Stonewall Jackson from Lynchburg to his home in Lexington, Virginia for burial; the American canal packet boats were narrow to accommodate canals, but might be 70–90 feet long. When the Erie Canal opened in New York state in 1825 along the Mohawk River, demand rose for travelers to be accommodated.
Canal packet boats included cabin space for up to 60 passengers. Unlike European and American sailing vessels, that sought to attain greater speed under sail, the canal packet boats were drawn through the Erie Canal by teams of two or three horses or mules. Compared to overland travel, the boats were much more comfortable. Travelers could get from New York City to Buffalo in ten days, with a combination of sailing and packet boats; some passengers took the boats to see both the natural landscapes. Thousands of others used packet boats to emigrate to Ohio and other parts of the Midwest; these boats were instrumental in the settling of and travel within Upstate New York through the branch canals such as the Chenango Canal. Packet boats were popular along the James River and Kanawha Canal in Virginia, allowing travel beyond the falls upriver. Mail steamers were steamships which carried the mail across waterways, such as across an ocean or between islands during the 19th century and early 20th century, when the cost of sending a letter was declining to the point an ordinary person could afford the cost of sending a letter across great distances.
In addition to carrying mail, most mail steamers carried passengers or cargo since the revenue from the mail service, if any, was insufficient by itself to pay for the cost of its travel. However, the advantage for a steamship carrying mail was that its arrival would be advertised in advance in the newspapers, thus giving it "free advertising" as a travel option for passengers or cargo. In most cases, mail carried by mail steamers was delivered to the post office to which it was addressed. In some cases, the incoming mail would be advertised in the local newspaper for pickup at the post office or at the steamship's office for a fee, if not fee-paid; because of political instability when a post office could not provide normal services, incoming mail from a mail steamer would be delivered to a local delivery service, which would deliver the mail and charge the addressee an extra fee for the service. When this occurred, the local delivery service would place its own local service stamp or mark on the envelope when the extra fee was paid.
Mail carried by these steamers – sometimes known as paquebot mail – was subject to various regulations by the governments involved as well as the Universal Postal Union's regulations stated at the UPU Vienna Conference of 1891. The C-82 Packet twin-engined, twin-boom cargo aircraft designed and built by Fairchild Aircraft was named as a tribute to the packet boat, it was used by the United States Army Air Forces and the successor United States Air Force following World War II. Allan Line Royal Mail Steamers Postal history Royal Mail Ship Pony Express TPO and Seapost Society for all collectors of Rail and Ship Mail worldwide Service Steamer Service Postal Matters Arrival of the Mail! Paquebot mail begins at sea, postmarked on land Glossary of Stamp Collecting Terms Alaska Mail Service: the Mail Steamer Elsie By the 1930s a method of signalling the impending arrival of a mail steamer at Aden was still needed Woodcut print 1875 photo of Olive, canal freighter Driver and team
Prussia was a prominent German state that originated in 1525 with a duchy centred on the region of Prussia on the southeast coast of the Baltic Sea. It was de facto dissolved by an emergency decree transferring powers of the Prussian government to German Chancellor Franz von Papen in 1932 and de jure by an Allied decree in 1947. For centuries, the House of Hohenzollern ruled Prussia expanding its size by way of an unusually well-organised and effective army. Prussia, with its capital in Königsberg and from 1701 in Berlin, decisively shaped the history of Germany. In 1871, German states united to create the German Empire under Prussian leadership. In November 1918, the monarchies were abolished and the nobility lost its political power during the German Revolution of 1918–19; the Kingdom of Prussia was thus abolished in favour of a republic—the Free State of Prussia, a state of Germany from 1918 until 1933. From 1933, Prussia lost its independence as a result of the Prussian coup, when the Nazi regime was establishing its Gleichschaltung laws in pursuit of a unitary state.
With the end of the Nazi regime, in 1945, the division of Germany into allied-occupation zones and the separation of its territories east of the Oder–Neisse line, which were incorporated into Poland and the Soviet Union, the State of Prussia ceased to exist de facto. Prussia existed de jure until its formal abolition by the Allied Control Council Enactment No. 46 of 25 February 1947. The name Prussia derives from the Old Prussians. In 1308, the Teutonic Knights conquered the region of Pomerelia with Gdańsk, their monastic state was Germanised through immigration from central and western Germany, and, in the south, it was Polonised by settlers from Masovia. The Second Peace of Thorn split Prussia into the western Royal Prussia, a province of Poland, the eastern part, from 1525 called the Duchy of Prussia, a fief of the Crown of Poland up to 1657; the union of Brandenburg and the Duchy of Prussia in 1618 led to the proclamation of the Kingdom of Prussia in 1701. Prussia entered the ranks of the great powers shortly after becoming a kingdom, exercised most influence in the 18th and 19th centuries.
During the 18th century it had a major say in many international affairs under the reign of Frederick the Great. During the 19th century, Chancellor Otto von Bismarck united the German principalities into a "Lesser Germany", which excluded the Austrian Empire. At the Congress of Vienna, which redrew the map of Europe following Napoleon's defeat, Prussia acquired rich new territories, including the coal-rich Ruhr; the country grew in influence economically and politically, became the core of the North German Confederation in 1867, of the German Empire in 1871. The Kingdom of Prussia was now so large and so dominant in the new Germany that Junkers and other Prussian élites identified more and more as Germans and less as Prussians; the Kingdom ended in 1918 along with other German monarchies that collapsed as a result of the German Revolution. In the Weimar Republic, the Free State of Prussia lost nearly all of its legal and political importance following the 1932 coup led by Franz von Papen. Subsequently, it was dismantled into Nazi German Gaue in 1935.
Some Prussian ministries were kept and Hermann Göring remained in his role as Minister President of Prussia until the end of World War II. Former eastern territories of Germany that made up a significant part of Prussia lost the majority of their German population after 1945 as the People's Republic of Poland and the Soviet Union both absorbed these territories and had most of its German inhabitants expelled by 1950. Prussia, deemed a bearer of militarism and reaction by the Allies, was abolished by an Allied declaration in 1947; the international status of the former eastern territories of Germany was disputed until the Treaty on the Final Settlement with Respect to Germany in 1990, while its return to Germany remains a topic among far right politicians, the Federation of Expellees and various political revisionists. The term Prussian has been used outside Germany, to emphasise professionalism, aggressiveness and conservatism of the Junker class of landed aristocrats in the East who dominated first Prussia and the German Empire.
The main coat of arms of Prussia, as well as the flag of Prussia, depicted a black eagle on a white background. The black and white national colours were used by the Teutonic Knights and by the Hohenzollern dynasty; the Teutonic Order wore a white coat embroidered with a black cross with gold insert and black imperial eagle. The combination of the black and white colours with the white and red Hanseatic colours of the free cities Bremen, Hamburg and Lübeck, as well as of Brandenburg, resulted in the black-white-red commercial flag of the North German Confederation, which became the flag of the German Empire in 1871. Suum cuique, the motto of the Order of the Black Eagle created by King Frederick I in 1701, was associated with the whole of Prussia; the Iron Cross, a military decoration created by King Frederick William III in 1813, was commonly associated with the country. The region populated by Baltic Old Prussians who were Christianised, became a favoured location for immigration by Germans, as well as Poles and Lithuanians along the border regions.
Before its abolition, the territory of the Kingdom of Prussia included the provinces of West Prussia.
Deptford, an area on the south bank of the River Thames in south-east London, is named after a ford of the River Ravensbourne. From the mid 16th century to the late 19th it was home to Deptford Dockyard, the first of the Royal Dockyards; this attracted Peter the Great to come and study shipbuilding. Deptford and the docks are associated with the knighting of Sir Francis Drake by Queen Elizabeth I aboard the Golden Hind, the legend of Sir Walter Raleigh laying down his cape for Elizabeth, Captain James Cook's third voyage aboard Resolution, the mysterious murder of Christopher Marlowe in a house along Deptford Strand. Though Deptford began as two small communities, one at the ford, the other a fishing village on the Thames, Deptford's history and population has been associated with the docks established by Henry VIII; the two communities flourished. The area declined as first the Royal Navy moved out, the commercial docks themselves declined until the last dock, Convoys Wharf, closed in 2000.
A Metropolitan Borough of Deptford was formed in 1900. Deptford began life as a ford of the Ravensbourne along the route of the Celtic trackway, paved by the Romans and developed into the medieval Watling Street; the modern name is a corruption of "deep ford". Deptford was part of the pilgrimage route from London to Canterbury used by the pilgrims in Chaucer's Canterbury Tales, is mentioned in the Prologue to the "Reeve's Tale"; the ford developed into first a wooden a stone bridge, in 1497 saw the Battle of Deptford Bridge, in which rebels from Cornwall, led by Michael An Gof, marched on London protesting against punitive taxes, but were soundly beaten by the King's forces. A second settlement, Deptford Strand, developed as a modest fishing village on the Thames until Henry VIII used that site for a royal dock repairing and supplying ships, after which it grew in size and importance, shipbuilding remaining in operation until March 1869. Trinity House, the organisation concerned with the safety of navigation around the British Isles, was formed in Deptford in 1514, with its first Master being Thomas Spert, captain of the Mary Rose.
It moved to Stepney in 1618. The name "Trinity House" derives from the church of Holy Trinity and St Clement, which adjoined the dockyard. Separated by market gardens and fields, the two areas merged over the years, with the docks becoming an important part of the Elizabethan exploration. Queen Elizabeth I visited; as well as for exploration, Deptford was important for trade - the Honourable East India Company had a yard in Deptford from 1607 until late in the 17th century taken over by the General Steam Navigation Company. It was connected with the slave trade, John Hawkins using it as a base for his operations, Olaudah Equiano, the slave who became an important part of the abolition of the slave trade, was sold from one ship's captain to another in Deptford around 1760. Diarist John Evelyn lived in Deptford at Sayes Court from 1652. Evelyn inherited the house when he married the daughter of Sir Richard Browne in 1652. On his return to England at the Restoration, Evelyn laid out meticulously planned gardens in the French style, of hedges and parterres.
In its grounds was a cottage at one time rented by master woodcarver Grinling Gibbons. After Evelyn had moved to Surrey in 1694, Russian Tsar Peter the Great studied shipbuilding for three months in 1698, he and some of his fellow Russians stayed at the manor house of Deptford. Evelyn was angered at the antics of the Tsar, who got drunk with his friends and, using a wheelbarrow with Peter in it, rammed their way through a fine holly hedge. Sayes Court was demolished in a workhouse built on its site. Part of the estates around Sayes Court were purchased in 1742 for the building of the Navy Victualling Yard, renamed the Royal Victoria Victualing Yard in 1858 after a visit by Queen Victoria; this massive facility included warehouses, a bakery, a cattleyard/abattoir and sugar stores, closed in 1961. All that remains is the name of Sayes Court Park, accessed from Sayes Court Street off Evelyn Street, not far from Deptford High Street; the Pepys Estate, opened on 13 July 1966, is on the former grounds of the Victualing Yard.
The Docks had been declining from the 18th century. When the Napoleonic Wars ended in 1815 the need for a Docks to build and repair warships declined. From 1871 until the First World War the shipyard site was the City of London Corporation's Foreign Cattle Market, in which girls and women butchered sheep and cattle until the early part of the 20th century. At its peak, around 1907, over 234,000 animals were imported annually through the market, but by 1912 these figures had declined to less than 40,000 a year; the yard was taken over by the War Office in 1914, was an Army Supply Reserve Depot in the First and Second World Wars. The site lay unused until being purchased by Convoys in 1984, came into the ownership of News International. In the mid-1990s, although significant inve
An ironworks or iron works is a building or site where iron is smelted and where heavy iron and steel products are made. The term is both singular and plural, i.e. the singular of ironworks is ironworks. Ironworks succeed bloomeries. An integrated ironworks in the 19th century included one or more blast furnaces and a number of puddling furnaces or a foundry with or without other kinds of ironworks. After the invention of the Bessemer process, converters became widespread, the appellation steelworks replaced ironworks; the processes carried at ironworks are described as ferrous metallurgy, but the term siderurgy is occasionally used. This is derived from the Greek words sideros - ergon or ergos - work; this is an unusual term in English, it is best regarded as an anglicisation of a term used in French and other Romance languages. Ironworks is used as an omnibus term covering works undertaking one or more iron-producing processes; such processes or species of ironworks where they were undertaken include the following: Blast furnaces — which made pig iron from iron ore.
A thin film of metal oxide forms on the anode in the intense heat. The oxide forms a protective layer. Finery forges — which fined pig iron to produce bar iron, using charcoal as fuel in a finery and coal or charcoal in a chafery, it was necessary for there to be a preliminary refining process in a coke refinery. After puddling, the puddled ball needed shingling and to be drawn out into bar iron in a rolling mill. From the 1850s, pig iron might be decarburised to produce mild steel using one of the following: The Bessemer process in a Bessemer converter, improved by the Gilchrist-Thomas process; the mills operating converters of any type are better called steelworks, ironworks referring to former processes, like puddling. After bar iron had been produced in a finery forge or in the forge train of a rolling mill, it might undergo further processes in one of the following: A slitting mill - which cut a flat bar into rod iron suitable for making into nails. A tinplate works - where rolling mills made sheets of iron, which were coated with tin.
A plating forge with a tilt hammer, a lighter hammer with a rapid stroke rate, enabling the production of thinner iron, suitable for the manufacture of knives, other cutlery, so on. A cementation furnace might be used to convert the bar iron into blister steel by the cementation process, either as an end in itself or as the raw material for crucible steel. Most of these processes did not produce finished goods. Further processes were manual, including Manufacturing by blacksmiths or more specialist kind of smith, it might be used in shipbuilding. In the context of the iron industry, the term manufacture is best reserved for this final stage; the notable ironworks of the world are described here by country. See above for the largest producers and the notable ironworks in the alphabetical order. Cape Town Iron and Steel Works in Kuilsrivier, Western Cape American Iron Works in Hyattsville, Maryland Bath Iron Works in Maine Burden Iron Works in Troy, New York Cambria Iron Company in Johnstown, Pennsylvania Falling Creek Ironworks, Virginia.
Saugus Iron Works in Saugus, Massachusetts Toledo Iron Works in Miami, Florida Tredegar Iron Works at Richmond, Virginia U. S. Steel Fairfield Works, near Birmingham, Alabama Gary Works, near Chicago, Illinois Granite City Works, near St. Louis, Missouri Great Lakes Works, near Detroit, Michigan Mon Valley Works, near Pittsubutgh, Pennsylvania Vulcan Iron Works in Pennsylvania and other places Anben Group, Anshan & Benxi, Liaoning Baosteel, Shanghai Baotou Steel, Inner Mongolia Shougang Group, Beijing Wuhan Steel, Hebei Five major steel works of Steel Authority of India, Ltd Kalinganagar Works of Tata Steel in Kalinganagar, Odisha Vijayanagar Works of JSW Steel in Bellary, Karnataka The largest Japanese steel companies' main works are as follows: JFE Steel Chiba Works, Chiba, of JFE Eastern Works Keihin Works, Kanagawa, of JFE Eastern Works Fukuyama Works, Hiroshima, of JFE Western Works Kurashiki Works, Okayama, of JFE Western Works Kobe Steel Kakogawa Steel Works, Hyogo Nippon Steel & Sumitomo Metal Hirohata Works, Hyogo Kimitsu Steel Works, of former Nippon Steel), Chiba Nagoya Works, Aichi Ōita Works, Ōita, Ōita Yawata Steel Works, Chiba Kashima Works, Ibaraki Wakayama Works, Wakayama POSCO Gwangyang Steelworks, south coast Pohang Steelworks, east coast
A paddle steamer is a steamship or riverboat powered by a steam engine that drives paddle wheels to propel the craft through the water. In antiquity, paddle wheelers followed the development of poles and sails, where the first uses were wheelers driven by animals or humans. In the early 19th century, paddle wheels were the predominant way of propulsion for steam-powered boats. In the late 19th century, paddle propulsion was superseded by the screw propeller and other marine propulsion systems that have a higher efficiency in rough or open water. Paddle wheels continue to be used by small pedal-powered paddle boats and by some ships that operate tourist voyages; the latter are powered by diesel engines. The paddle wheel is a large steel framework wheel; the outer edge of the wheel is fitted with regularly-spaced paddle blades. The bottom quarter or so of the wheel travels underwater. An engine rotates the paddle wheel in the water to produce backward as required. More advanced paddle wheel designs feature feathering methods that keep each paddle blade closer to vertical while in the water to increase efficiency.
The upper part of a paddle wheel is enclosed in a paddlebox to minimise splashing. There are two types of paddle wheel steamer, a sternwheeler with a single wheel on the rear, a sidewheeler with one on each side. Both were used as riverboats in the United States; some still operate for example on the Mississippi River. Although the first sternwheelers were invented in Europe, they saw the most service in North America on the Mississippi River. Enterprise was built at Brownsville, Pennsylvania, in 1814 as an improvement over the less efficient side wheelers; the second sternwheeler built, Washington of 1816, had two decks and served as the prototype for all subsequent steamboats of the Mississippi, including those made famous in Mark Twain's book Life on the Mississippi. Sidewheelers are used as coastal craft. Though the side wheels and enclosing sponsons make them wider than sternwheelers, they may be more maneuverable, since they can sometimes move the paddles at different speeds, in opposite directions.
This extra maneuverability makes sidewheelers popular on the narrower, winding rivers of the Murray-Darling system in Australia, where a number still operate. European sidewheelers, such as PS Waverley, connect the wheels with solid drive shafts that limit maneuverability and give the craft a wide turning radius; some were built with paddle clutches that disengage one or both paddles so they can turn independently. However, wisdom gained from early experience with sidewheelers deemed that they be operated with clutches out, or as solid shaft vessels. Crews noticed that as ships approached the dock, passengers moved to the side of the ship ready to disembark; the shift in weight, added to independent movements of the paddles, could lead to imbalance and potential capsizing. Paddle tugs were operated with clutches in, as the lack of passengers aboard meant that independent paddle movement could be used safely and the added maneuverability exploited to the full. In a simple paddle wheel, where the paddles are fixed around the periphery, power is lost due to churning of the water as the paddles enter and leave the water surface.
Ideally, the paddles should remain vertical while under water. This ideal can be approximated by use of linkages connected to a fixed eccentric; the eccentric is fixed forward of the main wheel centre. It is coupled to each paddle via a lever; the geometry is designed such that the paddles are kept vertical for the short duration that they are in the water. The use of a paddle wheel in navigation appears for the first time in the mechanical treatise of the Roman engineer Vitruvius, where he describes multi-geared paddle wheels working as a ship odometer; the first mention of paddle wheels as a means of propulsion comes from the 4th–5th century military treatise De Rebus Bellicis, where the anonymous Roman author describes an ox-driven paddle-wheel warship: The Italian physician Guido da Vigevano, planning for a new crusade, made illustrations for a paddle boat, propelled by manually turned compound cranks. One of the drawings of the Anonymous Author of the Hussite Wars shows a boat with a pair of paddle-wheels at each end turned by men operating compound cranks.
The concept was improved by the Italian Roberto Valturio in 1463, who devised a boat with five sets, where the parallel cranks are all joined to a single power source by one connecting-rod, an idea adopted by his compatriot Francesco di Giorgio. In 1704, the French physicist Denis Papin constructed the first ship powered by his steam engine, mechanically linked to paddles; this made him the first to construct a steam-powered boat. He has poured the first steam cylinder of the world in the iron foundry Veckerhagen. In 1787 Patrick Miller of Dalswinton invented a double-hulled boat, propelled on the Firth of Forth by men working a capstan that drove paddles on each side. One of the firsts functioning steamships, Palmipède, the first paddle steamer, was built in France in 1774 by Marquis Claude de Jouffroy and his colleagues; the 13-metre steamer with rotating paddles sailed on the Doubs River in June and July 1776. In 1783 a new paddle steamer by de Jouffroy, Pyroscaphe steamed up the river Saône for fifteen minutes before the engine failed.
Bureaucracy and the French Revolution thwarted further progress by de Jouffroy. The next successful attempt at a paddle-driven steam ship was by the Scottish engineer William Symington, who suggested steam power to Patrick Mi