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48-639: The Selborne Graving Dock is a dry dock in Simon's Town , South Africa. It is situated within the Naval Base Simon's Town . It is named for William Palmer, 2nd Earl of Selborne , the High Commissioner for Southern Africa at the time of construction. On 27 July 1900 a tender for the construction of a yard was awarded to Sir John Jackson Ltd . The construction used Portland cement from England, as well as granite blocks from Norway. The foundation stone

96-458: A Phoenician devised a new method of launching it (the Tessarakonteres ), having dug a trench under it, equal to the ship itself in length, which he dug close to the harbour. And in the trench he built props of solid stone five cubits deep, and across them he laid beams crosswise, running the laces whole width of the trench, at four cubits' distance from one another; and then making a channel from

144-462: A corn gallon of between 271 and 272 cubic inches. The wine , fluid , or liquid gallon has been the standard US gallon since the early 19th century . The wine gallon, which some sources relate to the volume occupied by eight medieval merchant pounds of wine, was at one time defined as the volume of a cylinder 6 inches deep and 7 inches in diameter, i.e. 6 in × ( ⁠3 + 1 / 2 ⁠  in) × π ≈ 230.907 06 cubic inches . It

192-406: A cylindrical measure of ⁠18 + 1 / 2 ⁠ inches in diameter and 8 inches in depth, which made the bushel 8 in × ( ⁠9 + 1 / 4 ⁠ in) × π ≈ 2150.42017 cubic inches . The bushel was later defined to be 2150.42 cubic inches exactly, thus making its gallon exactly 268.8025 in ( 4.404 883 770 86  L ); in previous centuries, there had been

240-415: A dock for a vessel of such a size might have had a volume of 750,000 gallons of water. Before the 15th century, when the hull below the waterline needed attention, careening was practised: at high tide the vessel was floated over a beach of hard sand and allowed to rest on one side when the tide receded. An account of 1434 described how a site near Southampton with a bottom of soft mud was selected for

288-477: A drydock and towed to their final place on the seabed. A dry dock may also be used for the prefabrication of the elements of an immersed tube tunnel, before they are floated into position, as was done with Boston's Silver Line . Gallon The gallon is a unit of volume in British imperial units and United States customary units . Three different versions are in current use: There are two pints in

336-408: A gallon, two imperial pints in a quart, and there are 20 imperial fluid ounces in an imperial pint, yielding 160 fluid ounces in an imperial gallon. The US liquid gallon (frequently called simply "gallon") is legally defined as 231 cubic inches , which is exactly 3.785411784 litres. A US liquid gallon can contain about 3.785 kilograms or 8.34 pounds of water at 3.98 °C (39.16 °F), and

384-410: A high cost. A floating dry dock is a type of pontoon for dry docking ships, possessing floodable buoyancy chambers and a U-shaped cross-section. The walls are used to give the dry dock stability when the floor or deck is below the surface of the water. When valves are opened, the chambers fill with water, causing the dry dock to float lower in the water. The deck becomes submerged and this allows

432-708: A number of ropes attached to the superstructure. The Saint-Nazaire 's Chantiers de l'Atlantique owns one of the biggest in the world: 1,200 by 60 metres (3,940 ft × 200 ft). The Alfredo da Silva Dry Dock in Almada , Portugal , was closed in 2000. The largest roofed dry dock is at the German Meyer Werft Shipyard in Papenburg , Germany , it is 504 m long, 125 m wide and stands 75 m tall. Harland and Wolff Heavy Industries in Belfast , Northern Ireland ,

480-476: A number of systems of liquid measurements in the United Kingdom prior to the 19th century. The British imperial gallon (frequently called simply "gallon") is defined as exactly 4.54609 dm (4.54609 litres). It is used in some Commonwealth countries, and until 1976 was defined as the volume of water at 62 °F (16.67 °C) whose mass is 10 pounds (4.5359237 kg). There are four imperial quarts in

528-498: A primary unit of trade, it can still be legally used in both the UK and Ireland as a supplementary unit. However, barrels and large containers of beer, oil and other fluids are commonly measured in multiples of an imperial gallon. Miles per imperial gallon is used as the primary fuel economy unit in the United Kingdom and as a supplementary unit in Canada on official documentation. Other than

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576-539: A quart and four quarts in a gallon. Different sizes of pints account for the different sizes of the imperial and US gallons. The IEEE standard symbol for both US (liquid) and imperial gallon is gal , not to be confused with the gal (symbol: Gal), a CGS unit of acceleration . The gallon currently has one definition in the imperial system, and two definitions (liquid and dry ) in the US customary system. Historically, there were many definitions and redefinitions. There were

624-546: A roof, to prevent spy satellites from taking pictures of the dry dock and any vessels that may be in it. During World War II , the German Kriegsmarine used fortified dry docks to protect its submarines from Allied air raids (see submarine pen ). An advantage of covered dry docks is that work can take place in any weather; this is frequently used by modern shipyards for construction especially of complex, high-value vessels like cruise ships, where delays would incur

672-460: A ship to be moved into position inside. When the water is pumped out of the chambers, the dry dock rises and the ship is lifted out of the water on the rising deck, allowing work to proceed on the ship's hull. A large floating dry dock involves multiple rectangular sections. These sections can be combined to handle ships of various lengths, and the sections themselves can come in different dimensions. Each section contains its own equipment for emptying

720-472: A small Italian book printed in Venice in 1560, called Descrittione dell'artifitiosa machina . In the booklet, an unknown author asks for the privilege of using a new method for the salvaging of a grounded ship and then proceeds to describe and illustrate his approach. The included woodcut shows a ship flanked by two large floating trestles, forming a roof above the vessel. The ship is pulled in an upright position by

768-412: A temporary revetted bank of rock and clay that had to be dug away by hand (an operation taking typically 29 days, working night and day to accord with the tides ) to allow the passage of a ship. Emptying was by a pump, possibly in the form of a bucket-chain powered by horses. This dry dock currently holds First World War monitor HMS M33 . Possibly the earliest description of a floating dock comes from

816-702: Is a stub . You can help Misplaced Pages by expanding it . Dry dock The use of dry docks in China goes at least as far back as the 10th century A.D. In 1088, Song dynasty scientist and statesman Shen Kuo (1031–1095) wrote in his Dream Pool Essays : At the beginning of the dynasty (c. +965) the two Che provinces (now Chekiang and southern Chiangsu) presented (to the throne) two dragon ships each more than 200 ft. in length. The upper works included several decks with palatial cabins and saloons, containing thrones and couches all ready for imperial tours of inspection. After many years, their hulls decayed and needed repairs, but

864-590: Is a covered, floating drydock that is also submersible to support the secret transfer of a mechanical lifting device underneath the Glomar Explorer ship, as well as the development of the Sea Shadow stealth ship . The Great Balance Dock , built in New York City in 1854, was the largest floating drydock in the world when it was launched. It was 325 feet (99 m) long and could lift 8,000 tons, accommodating

912-412: Is about 16.7% less than the imperial gallon. There are four quarts in a gallon, two pints in a quart and 16 US fluid ounces in a US pint , which makes the US fluid ounce equal to ⁠ 1 / 128 ⁠ of a US gallon. In order to overcome the effects of expansion and contraction with temperature when using a gallon to specify a quantity of material for purposes of trade, it is common to define

960-513: Is further divided into five fluid ounces, whereas the US gill is divided into four fluid ounces, meaning an imperial fluid ounce is ⁠ 1 / 20 ⁠ of an imperial pint, or ⁠ 1 / 160 ⁠ of an imperial gallon, while a US fluid ounce is ⁠ 1 / 16 ⁠ of a US pint, or ⁠ 1 / 128 ⁠ of a US gallon. Thus, the imperial gallon, quart, pint, cup and gill are approximately 20% larger than their US counterparts, meaning these are not interchangeable, but

1008-478: Is not used in commerce, and is also not listed in the relevant statute, which jumps from the dry pint to the bushel. As of 2021, the imperial gallon continues to be used as the standard petrol unit on 10 Caribbean island groups , consisting of: All 12 of the Caribbean islands use miles per hour for speed limits signage, and drive on the left side of the road . The United Arab Emirates ceased selling petrol by

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1056-647: Is the site of a large dry dock 556 by 93 metres (1,824 ft × 305 ft). The massive cranes are named after the Biblical figures Samson and Goliath . Dry Dock 12 at Newport News Shipbuilding at 662 by 76 metres (2,172 ft × 249 ft) is the largest dry dock in the United States. The largest floating-dock in North America is named The Vigorous. It is operated by Vigor Industries in Portland, OR, in

1104-482: The ballast and to provide the required services, and the addition of a bow section can facilitate the towing of the dry dock once assembled. For smaller boats, one-piece floating dry docks can be constructed or converted out of an existing obsolete barge, potentially coming with their own bow and steering mechanism. Shipyards operate floating dry docks as one method for hauling or docking vessels. Floating drydocks are important in locations where porous ground prevents

1152-535: The kilogram -litre relationship , the imperial gallon was based on the volume of 10 pounds of distilled water weighed in air with brass weights with the barometer standing at 30 inches of mercury (100 kilopascals ; 15 pounds per square inch ) and at a temperature of 62 °F (17 °C). In 1963, this definition was refined as the space occupied by 10 pounds of distilled water of density 0.998 859  g/mL weighed in air of density 0.001 217  g/mL against weights of density 8.136 g/mL (the original "brass"

1200-413: The wine gallon (equal in size to the US gallon), and the second one either the ale gallon or the larger imperial gallon. By the end of the 18th century, there were three definitions of the gallon in common use: The corn or dry gallon is used (along with the dry quart and pint) in the United States for grain and other dry commodities. It is one-eighth of the (Winchester) bushel, originally defined as

1248-556: The 1,000-foot AFDB-1 and the 850-foot AFDB-3 . The latter, an Advance Base Sectional Dock which saw action in Guam , was mothballed near Norfolk , Virginia , and was eventually towed to Portland , Maine , to become part of Bath Iron Works ' repair facilities. A downside of floating dry docks is that unscheduled sinkings and off-design dives may take place, as with the Russian dock PD-50 in 2018. The " Hughes Mining Barge ", or HMB-1,

1296-763: The Bahamas . In some parts of the Middle East, such as the United Arab Emirates and Bahrain , 18.9-litre water cooler bottles are marketed as five-gallon bottles. Both the US liquid and imperial gallon are divided into four quarts ( quart er gallons), which in turn are divided into two pints , which in turn are divided into two cups (not in customary use outside the US), which in turn are further divided into two gills . Thus, both gallons are equal to four quarts, eight pints, sixteen cups, or thirty-two gills. The imperial gill

1344-526: The Swan Island industrial area along the Willamette River. A graving dock is the traditional form of dry dock. It is a narrow basin, usually made of earthen berms and concrete, closed by gates or a caisson . A vessel is floated in with the gates open, then the gates are closed and the water is pumped out, leaving the craft supported on blocks. The keel blocks as well as the bilge block are placed on

1392-573: The United States, petrol is sold by the US gallon in 13 other countries, and one US territory: The latest country to cease using the gallon is El Salvador in June 2021. Both the US gallon and imperial gallon are used in the Turks and Caicos Islands (due to an increase in tax duties which was disguised by levying the same duty on the US gallon (3.79 L) as was previously levied on the Imperial gallon (4.55 L)) and

1440-446: The directive the gallon could still be used, but only as a supplementary or secondary unit. As a result of the EU directive Ireland and the United Kingdom passed legislation to replace the gallon with the litre as a primary unit of measure in trade and in the conduct of public business, effective from 31 December 1993, and 30 September 1995 respectively. Though the gallon has ceased to be

1488-421: The floor of the dock in accordance with the "docking plan" of the ship. Routine use of dry docks is for the "graving" i.e. the cleaning, removal of barnacles and rust, and re-painting of ships' hulls. Some fine-tuning of the ship's position can be done by divers while there is still some water left to manoeuvre the vessel. It is extremely important that supporting blocks conform to the structural members so that

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1536-549: The imperial fluid ounce is only approximately 4% smaller than the US fluid ounce, meaning these are often used interchangeably. Historically, a common bottle size for liquor in the US was the " fifth ", i.e. one-fifth of a US gallon (or one-sixth of an imperial gallon). While spirit sales in the US were switched to metric measures in 1976, a 750 mL bottle is still sometimes known as a "fifth". The term derives most immediately from galun , galon in Old Norman French , but

1584-572: The imperial gallon in 2010 and switched to the litre, with Guyana following suit in 2013. In 2014, Myanmar switched from the imperial gallon to the litre. Antigua and Barbuda has proposed switching to selling petrol by litres since 2015. In the European Union the gallon was removed from the list of legally defined primary units of measure catalogue in the EU directive 80/181/EEC for trading and official purposes, effective from 31 December 1994. Under

1632-594: The largest ships of its day. Apart from graving docks and floating dry docks, ships can also be dry docked and launched by: Some dry docks are used during the construction of bridges, dams, and other large objects. For example, the dry dock on the artificial island of Neeltje-Jans was used for the construction of the Oosterscheldekering , a large dam in the Netherlands that consists of 65 concrete pillars weighing 18,000 tonnes each. The pillars were constructed in

1680-400: The sea he filled all the space which he had excavated with water, out of which he easily brought the ship by the aid of whatever men happened to be at hand; then closing the entrance which had been originally made, he drained the water off again by means of engines (organois); and when this had been done the vessel rested securely on the before-mentioned cross-beams. It has been calculated that

1728-477: The ship is finished, the gates are opened to allow water in, and the ship is carefully refloated. Modern graving docks are box-shaped, to accommodate newer, boxier ships, whereas old dry docks are often shaped like the ships expected to dock there. This shaping was advantageous because such a dock was easier to build, it was easier to side-support the ships, and less water had to be pumped away. Dry docks used for building naval vessels may occasionally be built with

1776-429: The ship is not damaged when its weight is supported by the blocks. Some anti-submarine warfare warships have sonar domes protruding beneath the hull, requiring the hull to be supported several metres above the bottom of the dry dock, or depressions built into the floor of the dock, to accommodate the protrusions. Once the remainder of the water is pumped out, the ship can be freely inspected or serviced. When work on

1824-516: The ships could be protected from the elements and avoid the damage caused by undue exposure. The Greek author Athenaeus of Naucratis (V 204c-d) reports something that may have been a dry dock in Ptolemaic Egypt in the reign of Ptolemy IV Philopator (221-204 BC) on the occasion of the launch of the enormous Tessarakonteres rowing ship. However a more recent survey by Goodchild and Forbes does not substantiate its existence. But after that

1872-409: The ships were towed in above the beams. Then (breach now being closed) the water was pumped out by wheels so that the ships rested quite in the air. When the repairs were complete, the water was let in again, so that the ships were afloat once more (and could leave the dock). Finally the beams and pillars were taken away, and the whole basin covered over with a great roof so as to form a hangar in which

1920-423: The temperature at which the material will occupy the specified volume. For example, the volume of petroleum products and alcoholic beverages are both referenced to 60 °F (15.6 °C) in government regulations. Since the dry measure is one-eighth of a US Winchester bushel of 2,150.42 cubic inches, it is equal to exactly 268.8025 cubic inches, which is 4.404 883 770 86  L . The US dry gallon

1968-621: The usage was common in several languages, for example jale in Old French and gęllet (bowl) in Old English. This suggests a common origin in Romance Latin , but the ultimate source of the word is unknown. The gallon originated as the base of systems for measuring wine and beer in England. The sizes of gallon used in these two systems were different from each other: the first was based on

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2016-478: The use of conventional drydocks, such as at the Royal Naval Dockyard on the limestone archipelago of Bermuda . Another advantage of floating dry docks is that they can be moved to wherever they are needed and can also be sold second-hand. During World War II , the U.S. Navy used such auxiliary floating drydocks extensively to provide maintenance in remote locations. Two examples of these were

2064-401: The warship Grace Dieu , so that the hull would bed itself in and remain upright at low tide. A timber, brushwood and clay wall was then built up around the hull. The first early modern purpose-built European and oldest surviving dry dock still in use was commissioned by Henry VII of England at HMNB Portsmouth in 1495. This was a timber-lined excavation, with the seaward end closed off by

2112-477: The wine gallon had been used for centuries for import duty purposes, there was no legal standard of it in the Exchequer , while a smaller gallon (224 cu in) was actually in use, requiring this statute; the 231 cubic inch gallon remains the US definition today. In 1824, Britain adopted a close approximation to the ale gallon known as the imperial gallon , and abolished all other gallons in favour of it. Inspired by

2160-527: The work was impossible as long as they were afloat. So in the Hsi-Ning reign period (+1068 to +1077) a palace official Huang Huai-Hsin suggested a plan. A large basin was excavated at the north end of the Chin-ming Lake capable of containing the dragon ships, and in it heavy crosswise beams were laid down upon a foundation of pillars. Then (a breach was made) so that the basin quickly filled with water, after which

2208-579: Was laid on 15 November 1906  ( 1906-November-15 ) , and the dry dock was opened on 3 November 1910 ; 114 years ago  ( 1910-11-03 ) , by the Duke of Connaught. The Dockyard (including the dry dock) was handed to South Africa in 1957, as part of the Simonstown Agreement . This article about a South African building or structure is a stub . You can help Misplaced Pages by expanding it . This South African military article

2256-595: Was redefined during the reign of Queen Anne in 1706 as 231 cubic inches exactly, the earlier definition with π approximated to ⁠ 22 / 7 ⁠ . π r 2 h ≈ 22 7 × ( 7   i n 2 ) 2 × 6   i n = 231   i n 3 . {\displaystyle \pi r^{2}h\approx {\frac {22}{7}}\times \left({\frac {7~\mathrm {in} }{2}}\right)^{2}\times 6~\mathrm {in} =231~\mathrm {in} ^{3}.} Although

2304-407: Was refined as the densities of brass alloys vary depending on metallurgical composition), which was calculated as 4.546 091 879  L to ten significant figures. The precise definition of exactly 4.546 09 cubic decimetres (also 4.546 09  L , ≈  277.419 433  in ) came after the litre was redefined in 1964. This was adopted shortly afterwards in Canada, and adopted in 1976 in

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