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Post by Aloysius on Apr 1, 2023 17:02:34 GMT
Greek and Roman boats Greek kylix depicting Dionysus in a sailboat Greek kylix depicting Dionysus in a sailboat Little is known about the construction of small craft used by the Greeks and Romans, though the construction of ships from about 55 BCE can be described. The fragments of contemporary literature and art produce little more than some type names and the impression that some small boats were built with speed particularly in view. It is mere speculation to attempt to describe the individual types; apparently, many types first built as small boats became large, fast, rowing ships in a normal process of evolution.
A few small boats have been recovered, notably at Lake Nemi, Italy, and the construction of these is caravel, with sawed or hewed frames. In one of the vessels recovered at Lake Nemi, the frames are in futtocks, or pieces, that are not joined together, indicating that the planking or skin may have first been built and the frames inserted afterward. The hull planking is edge-fastened, in the same manner as in the large vessels of this period, using keys or tenons, at the seams, let into keel and garboard, or into adjoining strakes, each tenon secured by two pins or nails. The strakes are also nailed to the frames. In form, the example is nearly flat-bottomed, round bilged, double-ended, with flaring topsides, and greatest beam abaft midlength. The bottom, fore and aft, is slightly rockered with a rather long projecting beak or stem and a slightly raking post. The boat was about 31 feet (9.5 metres) long and 8 feet (2.5 metres) wide. The floor timbers reach the sides, in one piece; the topside frames are knees, standing square to the sides so requiring no beveling; the bottom legs of the knees are secured to the bottom plank.
This style of framing was utilized during the American Revolution on the gunboat Philadelphia, which was sunk during a naval battle on Lake Champlain in 1776 and is now exhibited in the Smithsonian Institution. The use of tenons, instead of edge-nailing, in the hull planking may represent a slow development from Egyptian construction to modern nailed caravel. The tenoned seams, as used in the Lake Nemi craft and in the remains of wine ships found in the Mediterranean off the coast of France, represent a method of building requiring great skill and much time.
Modern methods and materials Structural differences between a Canadian canoe (left) and a kayak. Canvas-covered hulls follow the general plan of birchbark canoe construction in that they have a plank lining supported by ribs. However, canvas boats have rigid framing systems. Canvas or other fabric over battens, following the basic Arctic skin-boat construction, is used in small folding boats and in kayaks, which were inspired in design and construction by the Eskimo skin kayak or hunting boat. Paper boats, made by cementing layers of paper over a hull mold, have been built successfully, and at one time this construction was popular for small boats and canoes in America. These boats had simple framing and, being made with water resistant adhesives, were strong and durable.
Boats on a beach, Curaçao. The use of veneer and plywood to build small craft developed very rapidly after 1920 in the United States. However, the use of plywood panels instead of planking not only required a complete framework but also limited the practical hull forms to V-bottom and flat-bottom types. Molded plywood, in which veneer sheets were laid over a mold with adhesive between two or more plies or skins, was the next development. This type of construction proved strong and lasting, although the use of a mold and the need for pressure-setting of the adhesives limited the types of molded plywood boat to those that could be mass-produced.
An open-water kayaker paddling through ocean waves. A great many small craft are built wholly or in part of thermosetting plastics. A mold is required, and there is usually a special textile employed to give strength to the hull skin. The usual method is to use layers of plastic over textile plies. Both hand applied and mechanically applied plastics are widely used. Metal or wooden stiffeners sometimes are used with the plastic shell, although all-plastic hulls are now quite common. Both molded plywood and plastic construction methods are best suited to mass-production building and therefore to small boats of the open or half-decked types.
Existing boat types Early boats boat boat A number of ancient boat types have survived into the present. The rafts still in use include the Brazilian jangada and the catamaran of Sri Lanka. The Brazilian and other sailing rafts have dagger boards or centreboards fitted between the two centre logs to allow windward sailing.
catamaran catamaran A large number of dugout canoe types remain in use. Some of these are merely trough-shaped hulls suitable only for protected waters, but others are well-developed craft. Until late in the 19th century the large single-log dugout canoes of the Northwest Coast Indians of North America were the best developed canoes of that type in existence. Multiple log canoes were used as sailing craft on Chesapeake Bay and large craft of a similar form and rig later developed under the type name bugeye. Large dugouts with built-up sides exist in the South Pacific and once were very numerous. The Pacific Island canoes are commonly narrow and require double hulls or outrigged floats on one or both sides for stability. One of the most notable of the single-outriggers is the flying proa, one of the fastest sailing boats in the world, first described by Capt. James Cook. The double-hulled craft are made of two canoes of equal size, placed side by side but at a short distance apart. These usually are used as sailing canoes and have come to be known as catamarans. The idea has been adapted by yachtsmen in the sailing catamaran or double-huller, ranked among the fastest sailing types known.
umiak umiak Skin boats have survived in the American Arctic in various tribal forms of the kayak or hunting boat and in the larger and open umiak. Other skin-covered craft, such as the English coracle for river fishing and the Irish curragh for sea fishing and transport, have continued in use for hundreds of years, although the modern versions have outer covers of canvas and tar instead of the original skins and tallow.
The birchbark canoe of the North American Indians could still be found in use into the early 20th century, but in most areas canvas had gradually taken the place of bark long before 1900. Bark canoes were also used by Aboriginal Australians well into the 19th century.
Viking Ship Britannica Quiz Sail Away: Vocabulary at Sea Quiz Sewed plank construction in the 20th century was mostly confined to some islands in the South Pacific, where basic dugouts were heightened by means of plank sides, and to some very limited areas where all-plank boats were built by this method. The basic advantages of sewed plank construction were utilized in a patented process, using copper or bronze wire, that was employed in England early in the 20th century for building high-speed motor boats.
National and regional boat types The need for craft of the boat class in fisheries, pilotage, salvage, and transport resulted in almost innumerable models, each designed for superior performance in a specific task and to meet geographic and economic needs.
Asia Sampan In East Asia the sampan is the commonest boat type, although the hull form, rig, and fittings vary widely. Some sampans have sharp bows; nearly all have large transom stems, and the after portion of the gunwale is higher than the forward portion. Sampans are often rigged for sailing with a single battened Chinese lugsail. Usually the boats have only one mast, but there are local types, notably in Hong Kong, equipped with two. The sampan is sculled with a large sweep balanced on the transom stern. It is usually open or partially decked and has a shelter or cabin aft for passengers or freight. In Japanese waters another form of sampan once was common, rigged with a rather primitive lugsail and with a peculiar form: the stem was straight and raking in profile and the forebody long and rather sharp, while the midsection was flat-bottomed. This model later developed into a motorboat and came to be used not only in Japan but in Hawaii and Taiwan.
In Southeast Asia the proa is the basic boat type. It is a fast, sharp-ended, rowing and sailing boat once popular with Malay pirates. The proa is open, long and rather narrow, with a "clipper" bow and a sharp stern. The boats are usually rigged with one or two sails somewhat like the Chinese lugsail. Early forms were built more than 60 feet (18 metres) in length and decked. The name proa is often applied both to this type and to the single-outrigger flying proa; however, the proa of the Pacific and the Malay boats are entirely different types.
In Indian waters there are a number of boat types, including dugouts with raised plank sides, sometimes fitted with outriggers, and plank boats with a long, straight, raking stem in profile, a transom stern, and a short keel. The latter are usually rigged with one mast and a settee sail. These boats vary locally in form and rig. One type, the pattamar, has greater depth at the bow than at the stern, and the keel profile is a hollow curve. Rigged with two or three masts, it is considered a fast sailer.
Middle East and Mediterranean dhow dhow In the Persian Gulf and southward along the east African coast the best known boats are usually classed as dhows. The two types so named are the bagala and sambuk. These have one or two settee sails, short keels, long and very raking curved stems, square stems, and a well-formed hull for fast sailing.
The boats of the Mediterranean basin are numerous in type and rig. One is the handsome Turkish caïque, a long, narrow rowing boat with graceful ends, designed for speed. These boats sometimes are rigged for sailing with a small spritsail or lugsail and in modern versions are often fitted with an outboard motor in a well at the stern. Small double-ended boats called sandals are also used. A square-stern sailing skiff of distinctive appearance is found on the Turkish Black Sea coast; it resembles a coaster of larger size known as the taka. A distinctive double-ended beach boat, known as the çektirme, is also found on the Turkish coast, although this name is more commonly applied to a larger auxiliary coaster.
On the Nile may be found the dahabeah, a sailing lighter and houseboat. This boat developed from the Nile gaiassa, a lighter and river freighter with a shallow hull like that of a canal boat, a high, sheer bow, and a huge outboard rudder. These boats usually have a large lateen sail forward and a small one aft, although some are fitted with only a single large sail. Another variation is the naggar, a sailing river lighter rigged with a single lugsail, with the boom along its foot parallel with its head.
gondola gondola The best known of Italian boats is the gondola of Venice, a double-ended craft, with ornamental posts at bow and stern, propelled by an oarsman using a single oar or sweep. The topo is a double-ended, flat-bottomed craft with a single mast carrying a lugsail or a small outboard motor.
Luxor, Egypt: feluccas on Nile River Luxor, Egypt: feluccas on Nile River The boomed standing lugsail was for a long time most common in the Adriatic, usually in a two-masted rig, while the lateen sail predominated in boats built in southern Italy, on the French Mediterranean coast, and in Spain and Portugal. Among small craft of the Mediterranean, combination rowing and sailing boats were once typical, rather than boats built to sail only, but in modern times engines have almost completely replaced sails. Many local types in the Mediterranean are loosely classed as feluccas, a term originally applied to two-masted lateen sail craft fitted to row and built for speed; later the name came to be applied also to three-masted craft of the galley type that had once been called xebecs.
Northern Europe and Britain The coast of northern France was the home of a number of types of square-sterned and sharp-sterned lug-rigged boats, usually two-masters. These boats were commonly of lapstrake construction and were good sailers, many carrying large areas of sail. The three-masted lugger or chasse-marée of France and a similar type built in England were fast enough to become the traditional craft of Channel smugglers.
England and Scotland produced many distinctive small boats; the coble, a square-sterned beach boat with deep forefoot, still survives as a motor fishing boat, as does the caravel-built Thames bawley. An extinct beach boat is the Yarmouth beach yawl, a long, narrow, lapstrake double-ender with sharp ends, built for salvage work and rigged with two or three lugsails and a jib.
punt punt Another noted English type was the Deal galley punt, a square-sterned, lapstrake open boat rigged with a single dipping lugsail and once used for salvage and rescue work off the beach. The cat was a larger lugger of two or three masts used at Deal; both types were very seaworthy and were fast sailers. Scotland produced many fine skiffs, the class name for a number of open or partly decked, lapstrake, one-masted, lug-rigged boats. The Lock Fyne skiff, the Fifie skiff, and the Scaffie and Zulu skiffs were fine examples of sailing and rowed fishing boats. The Shetland sexern was particularly fast and seaworthy; this type was rigged with a single lugsail, and its hull was low-sided and sharp-ended.
In the Netherlands and Belgium small boats fitted to sail had distinctive wing-shaped leeboards pivoted on each side at about amidships, to reduce leeway when sailing to windward. The boats were usually shallow in body and strongly built, with full, buoyant ends. Danish boats generally have sharper lines and deeper draft, and the smaller ones, commonly lapstrake built, sail and row well. The praam, a lapstrake boat with a square stern and a small transom bow, is a popular Danish type; formerly a sailing and rowing boat, it came to be used extensively as a motor boat. The praam can also be found on the Norwegian coast.
The predominance of the double-ended, lapstrake hull in Scandinavia is very marked, and some modern boats strongly resemble those of the Vikings. Scandinavian small boats are usually fast rowing and sailing craft with bow and stern sharp and curved in profile.
North America sloop sloop Many small boat types developed in North America during the 19th century. In eastern Canada the Labrador whaler, a lapstrake, double-ended rowing and sailing boat used in the Labrador fisheries, became popular, and its design appears to have inspired the design of the Tancook whaler, a schooner-rigged centreboard fishing boat notable for its excellent handling qualities. Another boat developed in the maritime provinces was the Cape Island sloop, a deep draft keel sloop once popular in the shore fisheries. On the Great Lakes the Canadians produced a two-masted, half decked, square-sterned Collingwood skiff, as well as a similar type in double-ended form. Perhaps the best known Canadian types are the lumber yard drive-boat or bateau, a double-ended, flat-bottomed rowing and poling boat used in the lumber drives when timber is floated downstream to the mills; and the York boat, a double-ended sailing and rowing boat used in the fur trade. The large birchbark maitre canot of the fur trade, an oversized version of the Indian canoe, also was once of economic importance.
dory dory The United States and Canada both produce the dory, the flat-bottomed skiff of the New England and Maritime Provinces fisheries. Some dories are fitted with centreboards for sailing. Others were equipped with engines, and this led to the design of special types in which rounded side frames replaced the straight frames of the regular fishing dory, producing a hull with an almost round bottom and a wide plank keel. This form of hull was carried to its highest degree of evolution in the New Jersey Seabright skiff or beach skiff, in which the bottom is very narrow and the sides very round. Formerly a rowing and sailing beach boat, the Seabright skiff developed into a high speed, seaworthy motorboat favoured for sport fishing.
Structure of a sailboat There have been hundreds of distinct types of small American sail and rowing boats under 40 feet in length. Some of the more notable of these are the Hampton boat of New England, first a lapstrake sail and rowing boat like the Labrador whaler but later a square-sterned, two-masted, half-decked boat equipped with a centreboard. This design was found suitable for the installation of engines and was gradually modified into a fishing launch. The Block Island boat and No Man’s Land boat were two-masted, double-ended beach boats notable for their seaworthiness. The New Haven sharpie was a large, two-masted, flat-bottomed boat, and its use spread southward to the Carolina sounds following the development of the oyster fisheries. Of a number of small sailing scows that also were employed in the U.S. fisheries, the New Jersey garvey is one of the better known. This type of sailing scow had one leeboard held to the side by a rack or iron bar-and-staple device and was usually rigged with one or two spritsails. It was used in the oyster and other inshore fisheries and in modern versions has been modified into a low-cost but efficient launch.
pirogue pirogue Another boat that has been adapted for use with engines is the New Orleans lugger. Originally a single-masted, square-sterned boat with a centreboard, the only lugger-rigged boat in the American fisheries, it was a fast sailer, and its good handling qualities made it ideal for use as a power boat. The San Francisco felucca, a single-masted, lateen-rigged fishing boat, also developed into a double-ended power craft now known as the Monterey boat. In its simplest form, the pirogue is a dugout, but later forms are more elaborate. These boats are widely distrubuted, as their shallow draft makes them useful for negotiating swamplands and shallow inlets.
Shipboats The boats carried on shipboard for harbour transportation, rescue work, and the like constitute a special class. Usually they are open boats fitted to row, although some are sailboats and many modern types have engines.
The largest boat on shipboard is the launch or longboat, originally a burdensome sailing and rowing boat capable of carrying such heavy loads as anchors and cannon. When steam engines became available, the launch became a self-propelled boat and later a motor boat. The cutter was a long, narrow boat especially designed for speed under either sail or oars; it usually was carried only by naval or revenue vessels. Another naval type was the gig, similar to the cutter but sharper in its lines, and usually reserved for the personal transport of high-ranking officers. Both the gig and cutter were designed with narrow transom stems and some rocker or curvature in the keels. Rigid inflatable launches are used by coast guard forces around the world to ensure compliance with maritime laws.
dinghy dinghy The yawl or dinghy, sometimes called a stern-boat when it was slung from davits at the stern of the ship, was a short, square-sterned rowing boat, either lapstrake- or caravel-planked, and sometimes fitted to sail. Modern yawls are powered, and the yawls carried aboard skipjacks, the V-bottomed sloops popular in Chesapeake Bay waters, are known as push-boats because they are used to push the mother ship in a calm.
The whaleboat was towed by a harpooned whale until the animal tired. Lances were then used for the kill. The whaleboat is a light, swift, rowing and sailing boat fitted with a centreboard; usually it is caravel-built, although lapstrake whaleboats predominated at one time. Developed for use by whaling crews, it has superior handling characteristics that made it popular as a general purpose ship’s boat, and it often serves as a cutter or gig.
lifeboats carrying Titanic survivors lifeboats carrying Titanic survivors The lifeboat is a double-ended rowing boat carried aboard ship for rescue purposes. Originally of wooden lapstrake construction, these boats now are almost universally made of steel, and some are equipped with diesel or gasoline engines. They often are built with special air chambers to make them unsinkable, and many are designed to be self-bailing and self-righting in heavy seas. The size and fitting of lifeboats are established by law, as is the number a ship must carry.
The Editors of Encyclopaedia Britannica This article was most recently revised and updated by Adam Augustyn. houseboat Home Visual Arts Architecture houseboat dwelling Written and fact-checked by Last Updated: Article History Srinagar, Jammu and Kashmir, India: Nagin Lake Srinagar, Jammu and Kashmir, India: Nagin Lake See all media Related Topics: watercraft house Experience a houseboat vacation down the Havel River in Germany Experience a houseboat vacation down the Havel River in GermanySee all videos for this article houseboat, in its simplest form, a cabin of one or two rooms built on a flat-bottomed scow, drawing only from 12 to 24 inches (roughly 30 to 60 cm) of water and usually with a platform or porch at either end.
houseboat houseboat houseboat houseboat Houseboats are found in great numbers on small rivers or streams—especially where there is good fishing—on the shallow waters of inland lakes, and in harbours along coastal regions. When used as summer homes, houseboats have developed into quite elaborate craft, having four or more rooms, with a broad porch or veranda on top protected by awnings. The hull construction still retains the characteristics of a flat-bottomed scow, having great stability. In this form the boats have no motive power and have to be towed from place to place when it is desired to change their position.
houseboat houseboat With the introduction of the internal-combustion engine, powered houseboats were developed and became popular because they could be moved from place to place easily. They combined the roominess and comfort of the houseboat with the convenience of the cabin cruiser. They are for the most part screw-driven and range in length from 45 feet (14 metres) to 100 feet (30 metres) or more. Being of shallow draft, they have living quarters in the superstructure, with large windows giving plenty of light and ventilation. These types of houseboats typically have broad decks, making them ideal summer homes. In the United States many of these power houseboats are used in northern waters during the summer months and taken south to Florida or the Gulf Coast during the winter months.
This article was most recently revised and updated by Michael Ray. catamaran Home Technology Cars & Other Vehicles catamaran boat Written and fact-checked by Last Updated: Article History catamaran catamaran See all media Related Topics: boat trimaran watercraft catamaran, twin-hulled sailing and powered boat developed for sport and recreation in the second half of the 20th century. Its design is based on a raft of two logs bridged by planks that had earlier been used by peoples in the Indonesian archipelago and throughout Polynesia and Micronesia. Early catamarans were up to 21.3 metres (70 feet) long, originally paddled by many men, and used for visiting, in war, and in exploration. Especially after the sail was added, voyages of more than 3,704 km (2,000 miles) were made.
The U.S. designer of America’s Cup boats Nathanael Herreshoff designed and built catamarans in the 1870s that sailed so successfully against monohulled boats that they were barred from organized racing. Production of the current form of catamaran, which averages about 12.2 metres (40 feet) in length, began in the 1950s. The early catamarans tended to have difficulty coming about when sailing to windward, but later designs overcame this. The catamaran remained difficult to right after capsizing, however. Smaller catamarans raced successfully against monohulled boats in 1959, and international competition began in 1961 between the United States and Great Britain, the latter winning through 1968. Thereafter, Danish and Australian boats also competed, the Australians dominating. Catamarans are very fast boats, achieving speeds of 32.19 km (20 miles) per hour. The addition of engines also made the catamaran a popular motor-cruising boat.
Nuclear powered aircraft carrier USS Carl vinson plows through the Indian ocean as aircraft on its flight deck are prepared for flight operations 3/15/05. Britannica Quiz Ships and Underwater Exploration The Editors of Encyclopaedia Britannica This article was most recently revised and updated by Adam Augustyn. shipping Home Technology Cars & Other Vehicles shipping water transportation Alternate titles: marine transportation Written and fact-checked by Last Updated: Article History shipping shipping See all media Key People: J. Bruce Ismay Edward J. Smith István, Count Széchenyi Henry Miller Shreve Daniel Keith Ludwig Related Topics: ship ship construction classification society watercraft waterway shipping, the transporting of goods and passengers by water. Described as the backbone of global trade, maritime shipping is responsible for the transport of the majority of raw materials, components, and finished products that drive the economy. Efficient and relatively low-cost, transoceanic shipping permits the efficient import and export of goods and supports the livelihoods of billions of people. In the first quarter of the 21st century, the global fleet of container ships, tankers, and dry bulk ships were responsible for transporting about 80 percent of world trade volume and about 70 percent of trade value.
Interactive map of major trade routes of ancient Greece and Phoenicia Interactive map of major trade routes of ancient Greece and Phoenicia Early civilizations, which arose by waterways, depended on watercraft for transport. The Egyptians were probably the first to use seagoing vessels (c. 1500 BCE); the Phoenicians, Cretans, Greeks, and Romans also relied on waterways. In Asia, Chinese ships equipped with multiple masts and a rudder were making sea voyages by about 200 CE; from as early as the 4th century BCE the Chinese also relied heavily on internal waterways to transport food to their large cities (see Grand Canal). Japan, too mountainous to rely on roads for mass transport, also relied on internal and coastal waterways for shipping from early in its history.
passenger ship More From Britannica ship: 15th-century ships and shipping medieval merchant ship medieval merchant ship The spice trade was a great stimulus to shipping trade; Arabians were sailing to the so-called Spice Islands of the East Indies before the Christian era, and European merchant marines grew up largely because of it. The tea trade had a similar effect, as did the discovery of gold in the New World. The development of shipping as a means of international trade shaped the formation of port cities in coastal regions across the globe. See also British East India Co.; Dutch East India Co.; French East India Co.
Brooks Brooks From the 17th to the 19th century, the slave trade was a major feature of Atlantic shipping and was responsible for the growth of the shipping fleets of a number of countries. It is estimated that there were more than 12,000 ships making over 40,000 voyages across the Atlantic during this time period. Prior to the 1600s, Portuguese merchants dominated the transatlantic slave trade, while the Dutch became the foremost traders of enslaved people during parts of the 1600s. English and French merchants controlled about half of the transatlantic slave trade in the 1700s, and an agreement between Spain and Britain granted the British a monopoly on the trade of enslaved people with the Spanish colonies. Nearly three-fifths of the total volume of the transatlantic slave trade took place during the 18th century, when the largest numbers of enslaved people were taken to the Americas and fleets based in the New World grew dramatically.
cargo ship cargo ship Following the abolition of slavery and the rise of the second Industrial Revolution, the U.S. and England were the ascendant shipping nations in the 19th century; Germany, Norway, Japan, the Netherlands, and France joined them in the early 20th century, with Greece dominating the industry by the century’s end. In the early 21st century, a number of Asian countries were listed among the top shipping nations, including China, Japan, Singapore, and South Korea. Many of the most important modern shipping routes are near-coastal and transoceanic, though major rivers, canals, and inland waterways are also economically important.
The economic importance of the shipping industry is not without significant environmental costs. Nearly all commercial shipping vessels run on fossil fuels, and the global shipping industry is thus a major contributor to the greenhouse gas emissions driving anthropogenic climate change. Fuel and sewage pollution from vessels into marine environments is also a concern. Given that many marine animals, especially whales and dolphins, rely on sound for communication and navigation and to locate prey, noise pollution from shipping activities harms wildlife and negatively impacts ocean ecosystems. Ship strikes are also a major cause of whale mortality. The indiscriminate release of ballast water (water used to help stabilize a ship) once cargo has been off-loaded is a common practice and has led to the introduction of invasive plants and animals into novel ecosystems.
Get a Britannica Premium subscription and gain access to exclusive content. The Editors of Encyclopaedia Britannica This article was most recently revised and updated by Melissa Petruzzello. pirogue Home Technology Cars & Other Vehicles pirogue boat Alternate titles: piragua Written and fact-checked by Last Updated: Article History pirogue pirogue See all media Related Topics: boat dugout watercraft pirogue, Spanish Piragua, in its simplest form, a dugout made from one log, but also a number of more elaborately fashioned boats, including various native canoes, the structure and appearance of which generally resemble those of a dugout. The pirogue is widely distributed and may be found as a fishing vessel in the Gulf of Mexico; as a shallow-draft boat that is used to maneuver through the Louisiana swamplands; and as a boat used by the Indians of Guyana. Pirogues may be broadened by constructing them from two curved pieces or deepened by affixing planks to their sides. Compare canoe.
This article was most recently revised and updated by Amy Tikkanen. anchor Home Technology Cars & Other Vehicles anchor nautical device Written and fact-checked by Last Updated: Article History Figure 1: Stock anchor anchor See all media Related Topics: stockless anchor mushroom anchor fluke stock anchor mooring buoy anchor, device, usually of metal, attached to a ship or boat by a cable or chain and lowered to the seabed to hold the vessel in a particular place by means of a fluke or pointed projection that digs into the sea bottom.
Ancient anchors consisted of large stones, basketfuls of stones, sacks filled with sand, or logs of wood loaded with lead; these held the vessel merely by their weight and by friction along the bottom. As ships became larger, they required a more effective device to hold them, and wooden hooks that dug into the sea bottom came into use as anchors. Iron replaced wood in their construction, and teeth or flukes were added to help the hooks dig into the bottom. Another major improvement was the addition of a stock, or horizontal arm, that is set at right angles to the arms and flukes of the lower part of the anchor. The stock ensures that the arms rest vertically on the seabed, and thus one fluke will dig itself in, providing maximum holding power. This type, with its two flukes and its stock at right angles, remained the basic anchor for many centuries. It is known as a stock anchor in the United States and as a fisherman’s anchor in the United Kingdom.
Nuclear powered aircraft carrier USS Carl vinson plows through the Indian ocean as aircraft on its flight deck are prepared for flight operations 3/15/05. Britannica Quiz Ships and Underwater Exploration Curved arms began to replace straight arms in anchors early in the 19th century. This type of anchor, which is still used for light work and for boats, is shown in Figure 1. The ring (or shackle) is the part of the anchor where the chain or cable is attached. By removing the keep pin, the stock can be removed from the head so that the anchor can be stowed flat on an anchor bed in the ship. The stock must then be folded out again (i.e., stocked) before letting go, to ensure that one of the flukes digs into the ground. The vertical shaft of an anchor is called a shank; it contains a balancing band fitted at the anchor’s centre of gravity so that the anchor balances horizontally when lifted. The shank is joined to each arm at the crown. At the end of each arm is a fluke, which consists of a triangular flat face (i.e., a palm) with a pointed bill that digs into the ground.
Figure 2: Stockless anchor The stockless anchor (Figure 2), which was patented in England in 1821, came into wide use principally because of its ease of handling and stowing. The crown, arms, and flukes of a stockless anchor are cast in one piece and can pivot slightly from side to side on the shank. The flukes are long and heavy, and have projecting shoulders at their base that catch on the seabed. As more drag is exerted, the shoulders force the flukes downward into the bottom. Stockless anchors have replaced the older stock anchor on most of the large ships of the world.
Several other types of anchors are in common use. Lightweight, Danforth, and plow anchors have long, sharp flukes that pivot around a stock at the bottom of the shank and bury themselves deeply into the bottom; these anchors are generally used for yachts and other small craft. The mushroom anchor is shaped like an upside-down mushroom and is used widely as a permanent mooring for lightships, dredges, and lighters.
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