A drydock is a narrow basin or vessel that can be flooded to allow a load to be floated in, then drained to allow that load to come to rest on a dry platform. Drydocks are used for the construction, maintenance, and repair of ships, boats, and other watercraft.
|“||But after that (the reign of Ptolemy IV Philopator) a Phoenician devised a new method of launching it (a ship), having dug a trench under it, equal to the ship itself in length, which he dug close to the harbour. Athenaeus ( Ancient Greek - Athếnaios Naukratios Latin Athenaeus Naucratita of Naucratis in Egypt Greek rhetorician and grammarian flourished Ptolemaic Egypt began when Ptolemy I Soter declared himself Pharaoh of Egypt in 305 BC and ended with the death of queen Cleopatra Ptolemy IV Philopator ( Greek:, Ptolemaĩos Philopátōr, reigned 221-205 BC son of Ptolemy III and Berenice II of Egypt was And in the trench he built props of solid stone five cubits deep, and across them he laid beams crosswise, running the whole width of the trench, at four cubits' distance from one another; and then making a channel from 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he easily brought the ship by the aid of whatever men happened to be at hand; then closing the entrance which had been originally made, he drained the water off again by means of engines (organois); and when this had been done the vessel rested securely on the before-mentioned cross-beams. ||”|
Since Athenaeus recorded the event 400 years later (around 200 AD), there is sufficient reason to believe that drydocks had been known throughout classical antiquity.
Drydocks appeared in China by 1070 A. The history of Science and Technology in China is both long and rich with many contributions to science and technology 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. The Song Dynasty ( Wade-Giles: Sung Ch'ao was a ruling dynasty in China between 960&ndash1279 CE it succeeded the Five Dynasties and Ten Kingdoms Shen Kuo or Shen Kua ( (1031&ndash1095 style name Cunzhong and pseudonym Mengqi Weng, was a Polymathic Chinese The Dream Pool Essays ( Pinyin: Meng Xi Bi Tan; Wade-Giles: Meng Ch'i Pi T'an Chinese: 夢溪筆談／梦溪笔谈 +965) the two Che provinces (now Chekiang and southern Chiangsu) presented (to the throne) two dragon ships each more than 200 ft. Zhejiang ( is an eastern coastal province of the People's Republic of China. ( Postal map spelling: Kiangsu) is a province of the People's Republic of China, located along the east coast of the country in length. The upper works included several decks with palatial cabins and saloons, containing thrones and couches all ready for imperial tours of inspection. A palace is a grand residence especially the home of a Head of state or some other high-ranking Public figure. A cabin or berthing is an enclosed room generally on a Ship or an Aircraft. After many years, their hulls decayed and needed repairs, but 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 the ships were towed in above the beams. The (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 the ships could be protected from the elements and avoid the damage caused by undue exposure. A hangar is an enclosed structure to hold Aircraft in protective storage (Wade-Giles spelling. Wade-Giles (ˌweɪdˈʤaɪlz) sometimes abbreviated Wade, is a Romanization system (phonetic notation and Transcription) for the Mandarin )||”|
In Europe, the first drydock, and the oldest surviving drydock, was commissioned by Henry VII of England at HMNB Portsmouth in 1495 (see The Tudors and the Royal Navy). Her Majesty's Naval Base (HMNB Portsmouth ( HMS ''Nelson'') is one of three operating bases for the Royal Navy (the others being HMNB Clyde and The Tudor era was a critical one in the development of the Royal Navy. Possibly the earliest description of a floating dock comes from 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 a number of ropes hanging down from the roof.
Harland and Wolff Heavy Industries in Belfast, is currently the largest in the world and is close to the slipway on which the ill-fated RMS Titanic was constructed. Harland and Wolff Heavy Industries is a diversified heavy industrial company specialising in Shipbuilding, Ship breaking, Offshore construction Belfast ( is the capital city of Northern Ireland and the seat of government in Northern Ireland. Construction The Titanic was a White Star Line ocean liner built at the Harland and Wolff shipyard in Belfast, Ireland The massive cranes are named after the Biblical figures Samson and Goliath. Samson and Goliath are twin Shipbuilding Gantry cranes situated at Queen's Island Belfast, Northern Ireland. Samson, Shimshon ( Hebrew: שמשון, Standard Šimšon Tiberian Šimšôn; meaning Goliath ( גָּלְיָת, Standard Hebrew Golyat, Tiberian Hebrew Golyāṯ, Arabic: جالوت Jalut (Muslim Goliath stands 96m tall, while Samson is taller at 106m.
Northrop Grumman Newport News Shipbuilding's Dry Dock 12 is the largest drydock in the USA. Northrop Grumman Shipbuilding ( NGS) formerly called Northrop Grumman Newport News ( NGNN) or Newport News Shipbuilding and Drydock Company The Saint-Nazaire's Chantiers de l'Atlantique owns one of the biggest in the world : 3937 feet x 196. See also the St Nazaire Raid Saint-Nazaire ( Breton: Sant-Nazer) is a town and ''commune'' in the Loire-Atlantique département Chantiers de l'Atlantique is one of the world's largest Shipyards based in Saint-Nazaire, France. 850 feet.
The classic form of drydock, properly known as graving dock, is a narrow basin, usually made of earthen berms and concrete, closed by gates or by a caisson, into which a vessel may be floated and the water pumped out, leaving the vessel supported on blocks. In Geotechnical engineering, a caisson is a retaining watertight structure used for example to work on the foundations of a Bridge pier, The keel blocks as well as the bilge block are placed on the floor of the dock in accordance with the "docking plan" of the ship.
Some fine-tuning of the ship's position is done by scuba divers while there is still some water left to manoeuvre it about. Scuba diving is swimming underwater, or taking part in another activity while using a Scuba set. It is extremely important that supporting blocks conform to the structural members so that the ship is not damaged when its weight is supported by the blocks. Some ASW warships have protruding sonar domes, requiring that the hull of the ship be supported several meters from the bottom of the drydock. Anti-submarine warfare (ASW or in older form A/S is a branch of Naval warfare that uses surface Warships Aircraft, space craft or other Submarines Sonar (which started as an Acronym for sound navigation and ranging) is a technique that uses Sound propagation (usually underwater to navigate
Once the remainder of the water is pumped out, the ship can be freely inspected or serviced. When work on the ship is finished, water is allowed to re-enter the dry dock and the ship is carefully refloated.
Modern graving docks are box-shaped, to accommodate the newer, boxier ship designs, whereas old drydocks are often shaped like the ships that are planned to be docked 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.
Drydocks used for building Navy vessels may occasionally be built with a roof. USS Michigan in popular culture In the game SOCOM II US Navy SEALs, USS Michigan is ordered to take up station off the coast of This is done to prevent spy satellites from taking pictures of the drydock and any ships or submarines that may be in it. A spy satellite (officially referred to as a reconnaissance satellite) is an Earth observation satellite or Communications satellite deployed for During World War II covered drydocks were frequently used by submarine fleets to protect them from enemy air raids, however their effectiveness in that role diminished after the Second World War. World War II, or the Second World War, (often abbreviated WWII) was a global military conflict which involved a majority of the world's nations, including A submarine is a Watercraft that can operate independently below water as distinct from a Submersible that has only limited underwater capability Today covered drydocks are usually used only when servicing or repairing a fleet ballistic missile submarine. A ballistic missile submarine is a Submarine equipped to launch Ballistic missiles ( SLBMs) Another advantage of covered drydocks is that one can work independent of the weather. This can save considerable time.
A floating drydock is a type of pontoon for dry docking ships, possessing floodable buoyancy chambers and a "U" shaped cross-section. Pontoon may refer to Pontoon (game, the Australian/Malaysian casino game Pontoon (card game, a chiefly British version of the card game A semi-submersible or semisubmersible is a Watercraft that can put much of its bulk underwater In Physics, buoyancy ( BrE IPA: /ˈbɔɪənsi/ is the upward Force on an object produced by the surrounding liquid or gas in which it is The walls are used to give the drydock stability when the floor is below the water level. When valves are opened the chambers are filled with water, the dry dock floats lower in the water, allowing a ship to be moved into position inside. For other uses see Valve (disambiguation. For the electronic component see Thermionic valve. When the water is pumped out of the chambers, the drydock rises and the deck is cleared of water, allowing work to proceed on the ship's hull.
Shipyards operate floating drydocks, among other means of hauling or docking vessels. The advantage of floating drydocks is that they can be moved all over the world and also can be sold second-hand. During World War II, the U.S. Navy used such (floating) drydocks extensively to provide maintenance in remote locations. World War II, or the Second World War, (often abbreviated WWII) was a global military conflict which involved a majority of the world's nations, including One of these, the 850-foot AFDB-3, 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. Guam ( Chamorro: cha Guåhån) officially the Territory of Guam, is an island in the western Pacific Ocean and is an organized unincorporated Norfolk is an Independent city in the Commonwealth of Virginia in the United States The Commonwealth of Virginia ( is an American state Portland is the largest city in the US state of Maine and the County seat of Cumberland County. The State of Maine ( is a state in the New England region of the northeastern United States of America, bordering the Atlantic Ocean Bath Iron Works (BIW is a Shipyard located on the Kennebec River in Bath Maine.
Apart from graving docks and floating drydocks, ships can also be drydocked and launched by:
Some drydocks are used during the construction of bridges, dams, and other large objects. For example, the drydock 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. Neeltje-Jans is an Artificial island in the Netherlands in the province of Zeeland, halfway between Noord-Beveland and Schouwen-Duiveland The Oosterscheldekering ( Eastern Scheldt Storm surge barrier between the islands Schouwen-Duiveland and Noord-Beveland, is the largest of the The Netherlands ( Dutch:, ˈnedərlɑnt is the European part of the Kingdom of the Netherlands, which consists of the Netherlands the Netherlands The pillars were constructed in a drydock and towed to their final place on the seabed.