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A ship is a large watercraft that travels the world's oceans and other sufficiently deep waterways, carrying goods or passengers, or in support of specialized missions, such as defense, research, and fishing. Ships are generally distinguished from boats, based on size, shape, load capacity, and tradition. In the Age of Sail a "ship" was a sailing vessel defined by its sail plan of at least three square riged masts and a full bowsprit.

Ships have supported exploration, trade, warfare, migration, colonization, and science. After the 15th century, new crops that had come from and to the Americas via the European seafarers significantly contributed to the world population growth.[1] Ship transport is responsible for the largest portion of world commerce.

As of 2016, there were more than 49,000 merchant ships, totaling almost 1.8 billion dead weight tons. Of these 28% were oil tankers, 43% were bulk carriers, and 13% were container ships.[2]

Nomenclature

Main parts of ship. 1Funnel; 2Stern; 3Propeller and Rudder; 4Portside (the right side is known as starboard); 5Anchor; 6Bulbous bow; 7Bow; 8Deck; 9Superstructure

Ships are generally larger than boats, but there is no universally accepted distinction between the two. Ships generally can remain at sea for longer periods of time than boats.[3] A legal definition of ship from Indian case law is a vessel that carries goods by sea.[4] A common notion is that a ship can carry a boat, but not vice versa.[5] A US Navy rule of thumb is that ships heel towards the outside of a sharp turn, whereas boats heel towards the inside[6] because of the relative location of the center of mass versus the center of buoyancy.[7][8] American and British 19th century maritime law distinguished "vessels" from other craft; ships and boats fall in one legal category, whereas open boats and rafts are not considered vessels.[9]

In the Age of Sail, a full-rigged ship was a sailing vessel with at least three square-rigged masts and a full bowsprit; other types of vessel were also defined by their sailplan, e.g. barque, brigantine, etc.[10]

A number of large vessels are usually referred to as boa

Ships have supported exploration, trade, warfare, migration, colonization, and science. After the 15th century, new crops that had come from and to the Americas via the European seafarers significantly contributed to the world population growth.[1] Ship transport is responsible for the largest portion of world commerce.

As of 2016, there were more than 49,000 merchant ships, totaling almost 1.8 billion dead weight tons. Of these 28% were oil tankers, 43% were bulk carriers, and 13% were container ships.[2]

Ships are generally larger than boats, but there is no universally accepted distinction between the two. Ships generally can remain at sea for longer periods of time than boats.[3] A legal definition of ship from Indian case law is a vessel that carries goods by sea.[4] A common notion is that a ship can carry a boat, but not vice versa.[5] A US Navy rule of thumb is that ships heel towards the outside of a sharp turn, whereas boats heel towards the inside[6] because of the relative location of the center of mass versus the center of buoyancy.[7][8] American and British 19th century maritime law distinguished "vessels" from other craft; ships and boats fall in one legal category, whereas open boats and rafts are not considered vessels.[9]

In the Age of Sail, a full-rigged ship was a sailing vessel with at least three square-rigged masts and a full bowsprit; other types of vessel were also defined by their sailplan, e.g. barque, brigantine, etc.[10]

A number of large vessels are usually referred to as boats. Submarines are a prime example.[11] Other types of large vessel which are traditionally called boats are Great Lakes freighters, riverboats, and ferryboats.[9] Though large enough to carry their own boats and heavy cargoes, these vessels are designed for operation on inland or protected coastal waters.

In most maritime traditions ships have individual names, and modern ships may belong to a ship class often named after its first ship.

Pronouns

In the northern parts of Europe and America a ship is traditionally referred to with a female grammatical gender, represented in English with the pronoun "she", even if named after a man. This is not universal usage and some English language journalistic style guides advise using "it" as referring to ships with female pronouns can be seen as offensive and outdated.[citation needed][12][13] In many documents the ship name is introduced with a ship prefix being an abbreviation of the ship class, for example "MS" (motor ship) or "SV" (sailing vessel), making it easier to distinguish a ship name from other individual names in a text.

History

Prehistory and antiquity

Asian developments

Egyptian sailing ship, c. 1422–1411 BC
A Phoenician ship carved on the face of a sarcophagus, c. 2nd century AD
One of the sailing trimarans depicted in Borobudur, c. 8th century AD

The first sea-going sailing ships were developed by the Austronesian peoples from what is now Southern China and Taiwan. Their invention of catamarans, outriggers, and crab claw sails enabled their ships to sail for vast distances in open ocean. It led to the Austronesian Expansion at around 3000 to 1500 BC. From Taiwan, they rapidly colonized the islands of Marit

In the Age of Sail, a full-rigged ship was a sailing vessel with at least three square-rigged masts and a full bowsprit; other types of vessel were also defined by their sailplan, e.g. barque, brigantine, etc.[10]

A number of large vessels are usually referred to as boats. Submarines are a prime example.[11] Other types of large vessel which are traditionally called boats are Great Lakes freighters, riverboats, and ferryboats.[9] Though large enough to carry their own boats and heavy cargoes, these vessels are designed for operation on inland or protected coastal waters.

In most maritime traditions ships have individual names, and modern ships may belong to a ship class often named after its first ship.

In the northern parts of Europe and America a ship is traditionally referred to with a female grammatical gender, represented in English with the pronoun "she", even if named after a man. This is not universal usage and some English language journalistic style guides advise using "it" as referring to ships with female pronouns can be seen as offensive and outdated.[citation needed][12][13] In many documents the ship name is introduced with a ship prefix being an abbreviation of the ship class, for example "MS" (motor ship) or "SV" (sailing vessel), making it easier to distinguish a ship name from other individual names in a text.

History

The first sea-going sailing ships were developed by the Austronesian peoples from what is now Southern China and Taiwan. Their invention of catamarans, outriggers, and crab claw sails enabled their ships to sail for vast distances in open ocean. It led to the Austronesian Expansion at around 3000 to 1500 BC. From Taiwan, they rapidly colonized the islands of Maritime Southeast Asia, then sailed further onwards to Micronesia, Island Melanesia, Polynesia, and Madagascar, eventually colonizing a territory spanning half the globe.[14][15][16]

Austronesian rigs were distinctive in that they had spars supporting both the upper and lower edges of the sails (and sometimes in between), in contrast to western rigs which only had a spar on the upper edge.[14][15][16] The sails were also made from woven leaves, usually from pandan plants.[17][18] These were complemented by paddlers, who usually positioned themselves on platforms on the outriggers in the larger boats.[15][19] Austronesian ships ranged in complexity from simple dugout canoes with outriggers or lashed together to large edge-pegged plank-built boats built around a keel made from a dugout canoe. Their designs were unique, evolving from ancient rafts to the characteristic double-hulled, single-outrigger, and double-outrigger designs of Austronesian ships.[16][19]

Early Austronesian sailors influenced the development of sailing technologies in Sri Lanka and Southern India through the Austronesian maritime trade network of the Indian Ocean, the precursor to the spice trade route and the maritime silk road, which was established at around 1500 BC.[20] Some scholars believe that the triangular Austronesian crab claw sail may have influenced the development of the lateen sail in western ships due to early contact.[16] The junk rigs of Chinese ships is also believed to be originally Javanese in origin.[21][22][23]

In the 1st century AD, the people from Nusantara archipelago already made large ships over 50 m long and stood out 4–7 m out of the water. They could carry 700-1000 people and 260 ton cargo. These ships known as kunlun bo or k'unlun po (崑崙舶, lit. "ship of the Kunlun people") by the Chinese and kolandiaphonta by the Greeks. It has 4-7 masts and able to sail against the wind due to the usage of tanja sails. These ships reaching as far as Ghana.[24]

In China, miniature models of ships that feature steering oars have been dated to the Warring States period (c. 475–221 BC).[25] By the Han dynasty, a well kept naval fleet was an integral part of the military. Sternpost-mounted rudders started to appear on Chinese ship models starting in the 1st century AD.[14][15][16] The sails were also made from woven leaves, usually from pandan plants.[17][18] These were complemented by paddlers, who usually positioned themselves on platforms on the outriggers in the larger boats.[15][19] Austronesian ships ranged in complexity from simple dugout canoes with outriggers or lashed together to large edge-pegged plank-built boats built around a keel made from a dugout canoe. Their designs were unique, evolving from ancient rafts to the characteristic double-hulled, single-outrigger, and double-outrigger designs of Austronesian ships.[16][19]

Early Austronesian sailors influenced the development of sailing technologies in Sri Lanka and Southern India through the Austronesian maritime trade network of the Indian Ocean, the precursor to the spice trade route and the maritime silk road, which was established at around 1500 BC.[20] Some scholars believe that the triangular Austronesian crab claw sail may have influenced the development of the lateen sail in western ships due to early contact.[16] The junk rigs of Chinese ships is also believed to be originally Javanese in origin.[21][22][23]

In the 1st century AD, the people from Nusantara archipelago already made large ships over 50 m long and stood out 4–7 m out of the water. They could carry 700-1000 people and 260 ton cargo. These ships known as kunlun bo or k'unlun po (崑崙舶, lit. "ship of the Kunlun people") by the Chinese and kolandiaphonta by the Greeks. It has 4-7 masts and able to sail against the wind due to the usage of tanja sails. These ships reaching as far as Ghana.[24]

In China, miniature models of ships that feature steering oars have been dated to the Warring States period (c. 475–221 BC).[25] By the Han dynasty, a well kept naval fleet was an integral part of the military. Sternpost-mounted rudders started to appear on Chinese ship models starting in the 1st century AD.[25] However, these early Chinese ships were fluvial (riverine), and were not seaworthy.[26][27] The Chinese only acquired sea-going ship technologies in the 10th century AD Song Dynasty after contact with Southeast Asian djong trading ships, leading to the development of the junks.[21][22][23]

In 3000 BC, Ancient Egyptians learned how to assemble wooden planks into a hull.[28] They used woven straps to lash the planks together,[28] and reeds or grass stuffed between the planks helped to seal the seams.[28][note 1] The Greek historian and geographer Agatharchides had documented ship-faring among the early Egyptians: "During the prosperous period of the Old Kingdom, between the 30th and 25th centuries BC, the river-routes were kept in order, and Egyptian ships sailed the Red Sea as far as the myrrh-country."[29] Sneferu's ancient cedar wood ship Praise of the Two Lands is the first reference recorded (2613 BC) to a ship being referred to by name.[30]

The ancient Egyptians were perfectly at ease building sailboats. A remarkable example of their shipbuilding skills was the Khufu ship, a vessel 143 feet (44 m) in length entombed at

The ancient Egyptians were perfectly at ease building sailboats. A remarkable example of their shipbuilding skills was the Khufu ship, a vessel 143 feet (44 m) in length entombed at the foot of the Great Pyramid of Giza around 2500 BC and found intact in 1954.

The oldest discovered sea faring hulled boat is the Late Bronze Age Uluburun shipwreck off the coast of Turkey, dating back to 1300 BC.[31]

By 1200 B.C., the Phoenicians were building large merchant ships. In world maritime history, declares Richard Woodman, they are recognized as “the first true seafarers, founding the art of pilotage, cabotage, and navigation” and the architects of “the first true ship, built of planks, capable of carrying a deadweight cargo and being sailed and steered.” [32]

At this time, ships were developing in Asia in much the same way as Europe.[according to whom?] Japan used defensive naval techniques in the Mongol invasions of Japan in 1281. It is likely that the Mongols of the time took advantage of both European and Asian shipbuilding techniques.[according to whom?] During the 15th century, China's Ming dynasty assembled one of the largest and most powerful naval fleets in the world for the diplomatic and power projection voyages of Zheng He. Elsewhere in Japan in the 15th century, one of the world's first iron-clads, "Tekkōsen" (鉄甲船), literally meaning "iron ships",[33] was also developed. In Japan, during the Sengoku era from the fifteenth to 17th century, the great struggle for feudal supremacy was fought, in part, by coastal fleets of several hundred boats, including the atakebune. In Korea, in the early 15th century during the Joseon era, "Geobukseon"(거북선), was developed. The "turtle ship", as it was called is recognized as the first armored ship in the world.

A Japanese atakebune from the 16th century

European developments

Replica of Magellan's Victoria. Ferdinand Magellan led the first expedition that Renaissance, navigational technology remained comparatively primitive compared to Austronesian cultures.[citation needed] This absence of technology did not prevent some civilizations from becoming sea powers. Examples include the maritime republics of Genoa and Venice, Hanseatic League, and the Byzantine navy. The Vikings used their knarrs to explore North America, trade in the Baltic Sea and plunder many of the coastal regions of Western Europe.

Towards the end of the 14th century, ships like the carrack began to develop towers on the bow and stern. These towers decreased the vessel's stability, and in the 15th century, the caravel, designed by the Portuguese, based on the Arabic qarib which could sail closer to the wind, became more widely used. The towers were gradually replaced by the forecastle and sterncastle, as in the carrack Santa María of Christopher Columbus. This increased freeboard allowed another innovation: the freeing port, and the artillery associated with it.

The carrack and then the caravel were developed in Portugal. After Columbus, European exploration rapidly accelerated, and many new trade routes were established.[34] In 1498, by reaching India, Vasco da Gama proved that the access to the Indian Ocean from the Atlantic was possible. These explorations in the Atlantic and Indian Oceans were soon followed by France, England and the Netherlands, who explored the Portuguese and Spanish trade routes into the Pacific Ocean, reaching Australia in 1606 and New Zealand in 1642.Towards the end of the 14th century, ships like the carrack began to develop towers on the bow and stern. These towers decreased the vessel's stability, and in the 15th century, the caravel, designed by the Portuguese, based on the Arabic qarib which could sail closer to the wind, became more widely used. The towers were gradually replaced by the forecastle and sterncastle, as in the carrack Santa María of Christopher Columbus. This increased freeboard allowed another innovation: the freeing port, and the artillery associated with it.

The carrack and then the caravel were developed in Portugal. After Columbus, European exploration rapidly accelerated, and many new trade routes were established.[34] In 1498, by reaching India, Vasco da Gama proved that the access to the Indian Ocean from the Atlantic was possible. These explorations in the Atlantic and Indian Oceans were soon followed by France, England and the Netherlands, who explored the Portuguese and Spanish trade routes into the Pacific Ocean, reaching Australia in 1606 and New Zealand in 1642.[35]

Parallel to the development of warships, ships in service of marine fishery and trade also developed in the period between antiquity and the Renaissance.

Maritime trade was driven by the development of shipping companies with significant financial resources. Canal barges, towed by draft animals on an adjacent towpath, contended with the railway up to and past the early days of the industrial revolution. Flat-bottomed and flexible scow boats also became widely used for transporting small cargoes. Mercantile trade went hand-in-hand with exploration, self-financed by the commercial benefits of exploration.

During the first half of the 18th century, the French Navy began to develop a new type of vessel known as a ship of the line, featuring seventy-four guns. This type of ship became the backbone of all European fighting fleets. These ships were 56 metres (184 ft) long and their construction required 2,800 oak trees and 40 kilometres (25 mi) of rope; they carried a crew of about 800 sailors and soldiers.

During the 19th century the Royal Navy enforced a ban on the slave trade, acted to suppress piracy, and continued to map the world. A clipper was a very fast sailing ship of the 19th century. The clipper routes fell into commercial disuse with the introduction of steam ships with better fuel efficiency, and the opening of the Suez and Panama Canals.

Ship designs stayed fairly unchanged until the late 19th century. The industrial revolution, new mechanical methods of propulsion, and the ability to construct ships from metal triggered an explosion in ship design. Factors including the quest for more efficient ships, the end of long running and wasteful maritime conflicts, and the increased financial capacity of industrial powers created an avalanche of more specialized boats and ships. Ships built for entirely new functions, such as firefighting, rescue, and research, also began to appear.

21st century

Colombo Express, one of the largest container ships in the world, owned and operated by Hapag-Lloyd of Germany

In 2019, the world's fleet included 51,684 commercial vessels with gross tonnage of more than 1,000 tons, totaling 1.96 billion tons.[37] Such ships carried 11 billion tons of cargo in 2018, a sum that grew by 2.7% over the previous year.[38] In terms of tonnage, 29% of ships were tankers, 43% are bulk carriers, 13% container ships and 15% were other types.[39]

In 2002, there were 1,240 warships operating in the world, not counting small vessels such as patrol boats. The United States accounted for 3 million tons worth of these vessels, Russia 1.35 million tons, the United Kingdo

Maritime trade was driven by the development of shipping companies with significant financial resources. Canal barges, towed by draft animals on an adjacent towpath, contended with the railway up to and past the early days of the industrial revolution. Flat-bottomed and flexible scow boats also became widely used for transporting small cargoes. Mercantile trade went hand-in-hand with exploration, self-financed by the commercial benefits of exploration.

During the first half of the 18th century, the French Navy began to develop a new type of vessel known as a ship of the line, featuring seventy-four guns. This type of ship became the backbone of all European fighting fleets. These ships were 56 metres (184 ft) long and their construction required 2,800 oak trees and 40 kilometres (25 mi) of rope; they carried a crew of about 800 sailors and soldiers.

During the 19th century the Royal Navy enforced a ban on the slave trade, acted to suppress piracy, and continued to map the world. A clipper was a very fast sailing ship of the 19th century. The clipper routes fell into commercial disuse with the introduction of steam ships with better fuel efficiency, and the opening of the Suez and Panama Canals.

Ship designs stayed fairly unchanged until the late 19th century. The industrial revolution, new mechanical methods of propulsion, and the ability to construct ships from metal triggered an explosion in ship design. Factors including the quest for more efficient ships, the end of long running and wasteful maritime conflicts, and the increased financial capacity of industrial powers created an avalanche of more specialized boats and ships. Ships built for entirely new functions, such as firefighting, rescue, and research, also began to appear.

In 2019, the world's fleet included 51,684 commercial vessels with gross tonnage of more than 1,000 tons, totaling 1.96 billion tons.[37] Such ships carried 11 billion tons of cargo in 2018, a sum that grew by 2.7% over the previous year.[38] In terms of tonnage, 29% of ships were tankers, 43% are bulk carriers, 13% container ships and 15% were other types.[39]

In 2002, there were 1,240 warships operating in the world, not counting small vessels such as patrol boats. The United States accounted for 3 million tons worth of these vessels, Russia 1.35 million tons, the United Kingdom 504,660 tons and China 402,830 tons. The 20th century saw many naval engagements during the two world wars, the Cold War, and the rise to power of naval forces of the two blocs. The world's major powers have recently used their naval power in cases such as the United Kingdom in the Falkland Islands and the United States in Iraq.

The size of the world's fishing fleet is more difficult to estimate. The largest of these are counted as commercial vessels, but the

In 2002, there were 1,240 warships operating in the world, not counting small vessels such as patrol boats. The United States accounted for 3 million tons worth of these vessels, Russia 1.35 million tons, the United Kingdom 504,660 tons and China 402,830 tons. The 20th century saw many naval engagements during the two world wars, the Cold War, and the rise to power of naval forces of the two blocs. The world's major powers have recently used their naval power in cases such as the United Kingdom in the Falkland Islands and the United States in Iraq.

The size of the world's fishing fleet is more difficult to estimate. The largest of these are counted as commercial vessels, but the smallest are legion. Fishing vessels can be found in most seaside villages in the world. As of 2004, the United Nations Food and Agriculture Organization estimated 4 million fishing vessels were operating worldwide.[40] The same study estimated that the world's 29 million fishermen[41] caught 85,800,000 tonnes (84,400,000 long tons; 94,600,000 short tons) of fish and shellfish that year.[42]

Because ships are constructed using the principles of naval architecture that require same structural components, their classification is based on their function such as that suggested by Paulet and Presles,[43] which requires modification of the components. The categories accepted in general by naval architects are:[44]

  • High-speed craftMultihulls including wave piercers, small-waterplane-area twin hull (SWATH), surface effect ships and hovercraft, hydrofoil, Inland vessels
    Passenger ship of Köln-Düsseldorfer on the river Rhine
    Hurma, Hans and Voima at the Lake Saimaa in the harbour of Imatra, Finland, at a heritage ship meeting in 2009

    Freshwater shipping may occur on lakes, rivers and canals. Ships designed for those venues may be specially adapted to the widths and depths of specific waterways. Examples of freshwater waterways that are navigable in part by large vessels include the Danube, Mississippi, Rhine, Yangtze and Amazon Rivers, and the Great Lakes.

    Great Lakes

    Lake freighters, also called lakers, are cargo vessels that ply the Great Lakes. The most well-known is SS Edmund Fitzgerald, the latest major vessel to be wrecked on the Lakes. These vessels are traditionally called boats, not ships. Visiting ocean-going vessels are called "salties." Because of their additional beam, very large salties are never seen inland of the Saint Lawrence Seaway. Because the smallest of the Soo Locks is larger than any Seaway lock, salties that can pass through the Seaway may travel anywhere in the Great Lakes. Because of their deeper draft, salties may accept partial loads on the Great Lakes, "topping off" when they have exited the Seaway. Similarly, the largest lakers are confined to the Upper Lakes (Superior, Michigan, Danube, Mississippi, Rhine, Yangtze and Amazon Rivers, and the Great Lakes.

    Great Lakes

    Lake freighters, also called lakers, are cargo vessels that ply the Great Lakes. The most well-known is SS Edmund Fitzgerald, the latest major vessel to be wrecked on the Lakes. These vessels are traditionally called boats, not ships. Visiting ocean-going vessels are called "salties." Because of their additional beam, very large salties are never seen inland of the Saint Lawrence Seaway. Because the smallest of the Soo Locks is larger than any Seaway lock, salties that can pass through the Seaway may travel anywhere in the Great Lakes. Because of their deeper draft, salties may accept partial loads on the Great Lakes, "topping off" when they have exited the Seaway. Similarly, the largest lakers are confined to the Upper Lakes (Superior, Michigan, Huron, Erie) because they are too large to use the Seaway locks, beginning at the Welland Canal that bypasses the Niagara River.

    Since the freshwater lakes are less corrosive to ships than the salt water of the oceans, lakers tend to last much longer than ocean freighters. Lakers older than 50 years are not unusual, and as of 2005, all were over 20 years of age.Lake freighters, also called lakers, are cargo vessels that ply the Great Lakes. The most well-known is SS Edmund Fitzgerald, the latest major vessel to be wrecked on the Lakes. These vessels are traditionally called boats, not ships. Visiting ocean-going vessels are called "salties." Because of their additional beam, very large salties are never seen inland of the Saint Lawrence Seaway. Because the smallest of the Soo Locks is larger than any Seaway lock, salties that can pass through the Seaway may travel anywhere in the Great Lakes. Because of their deeper draft, salties may accept partial loads on the Great Lakes, "topping off" when they have exited the Seaway. Similarly, the largest lakers are confined to the Upper Lakes (Superior, Michigan, Huron, Erie) because they are too large to use the Seaway locks, beginning at the Welland Canal that bypasses the Niagara River.

    Since the freshwater lakes are less corrosive to ships than the salt water of the oceans, lakers tend to last much longer than ocean freighters. Lakers older than 50 years are not u

    Since the freshwater lakes are less corrosive to ships than the salt water of the oceans, lakers tend to last much longer than ocean freighters. Lakers older than 50 years are not unusual, and as of 2005, all were over 20 years of age.[45]

    SS St. Marys Challenger, built in 1906 as William P Snyder, was the oldest laker still working on the Lakes until its conversion into a barge starting in 2013. Similarly, E.M. Ford, built in 1898 as Presque Isle, was sailing the lakes 98 years later in 1996. As of 2007 E.M. Ford was still afloat as a stationary transfer vessel at a riverside cement silo in Saginaw, Michigan.

    Merchant ships are ships used for commercial purposes and can be divided into four broad categories: fishing, cargo ships, passenger ships, and special-purpose ships.[46] The UNCTAD review of maritime transport categorizes ships as: oil tankers, bulk (and combination) carriers, general cargo ships, container ships, and "other ships", which includes "liquefied petroleum gas carriers, liquefied natural gas carriers, parcel (chemical) tankers, specialized tankers, reefers, offshore supply, tugs, dredgers, cruise, ferries, other non-cargo". General cargo ships include "multi-purpose and project vessels and roll-on/roll-off cargo".[2]

    Modern commercial vessels are typically powered by a single propeller driven by a diesel or, less usually, gas turbine engine.,[47] but until the mid-19th century they were predominantly square sail rigged. The fastest vessels may use pump-jet engines.[citation needed] Most commercial vessels have full hull-forms to maximize cargo capacity.[citation needed] Hulls are usually made of steel, although aluminum can be used on faster craft, and fiberglass on the smallest service vessels.[citation needed] Commercial vessels generally have a crew headed by a sea captain, with deck officers and engine officers on larger vessels. Special-purpose vessels often have specialized crew if necessary, for example scientists aboard diesel or, less usually, gas turbine engine.,[47] but until the mid-19th century they were predominantly square sail rigged. The fastest vessels may use pump-jet engines.[citation needed] Most commercial vessels have full hull-forms to maximize cargo capacity.[citation needed] Hulls are usually made of steel, although aluminum can be used on faster craft, and fiberglass on the smallest service vessels.[citation needed] Commercial vessels generally have a crew headed by a sea captain, with deck officers and engine officers on larger vessels. Special-purpose vessels often have specialized crew if necessary, for example scientists aboard research vessels.

    Fishing boats are generally small, often little more than 30 meters (98 ft) but up to 100 metres (330 ft) for a large tuna or whaling ship. Aboard a fish processing vessel, the catch can be made ready for market and sold more quickly once the ship makes port. Special purpose vessels have special gear. For example, trawlers have winches and arms, stern-trawlers have a rear ramp, and tuna seiners have skiffs. In 2004, 85,800,000 tonnes (84,400,000 long tons; 94,600,000 short tons) of fish were caught in the marine capture fishery.[48] Anchoveta represented the largest single catch at 10,700,000 tonnes (10,500,000 long tons; 11,800,000 short tons).[48] That year, the top ten marine capture species also included Alaska pollock, Blue whiting, Skipjack tuna, Atlantic herring, Chub mackerel, Japanese anchovy, Chilean jack mackerel, Largehead hairtail, and Yellowfin tuna.[48] Other species including salmon, shrimp, lobster, clams, squid and crab, are also commercially fished. Modern commercial fishermen use many methods. One is fishing by nets, such as purse seine, beach seine, lift nets, gillnets, or entangling nets. Another is trawling, including bottom trawl. Hooks and lines are used in methods like long-line fishing and hand-line fishing. Another method is the use of fishing trap.

    Cargo ships transport dry and liquid cargo. Dry cargo can be transported in bulk by bulk carriers, packed directly onto a general cargo ship in break-bulk, packed in intermodal containers as aboard a container ship, or driven aboard as in roll-on roll-off ships. Liquid cargo is generally carried in bulk aboard tankers, such as oil tankers which may include both crude and finished products of oil, chemical tankers which may also carry vegetable oils other than chemicals and gas carriers, although smaller shipments may be carried on container ships in tank containers.[49]

    Passenger ships range in size from small river ferries to very large cruise ships. This type of vessel includes ferries, which move passengers and vehicles on short trips; ocean liners, which carry passengers from one place to another; and cruise ships, which carry passengers on voyages undertaken for pleasure, visiting several places and with leisure activities on board, often returning them to the port of embarkation. Riverboats and inland ferries are specially designed to carry passengers, cargo, or both in the challenging river environment. Rivers present special hazards to vessels. They usually have varying water flows that alternately lead to high speed water flows or protruding rock hazards. Changing siltation patterns may cause the sudden appearance of shoal waters, and often floating or sunken logs and trees (called snags) can endanger the hulls and propulsion of riverboats. Riverboats are generally of shallow draft, being broad of beam and rather square in plan, with a low freeboard and high topsides. Riverboats can survive with this type of configuration as they do not have to withstand the high winds or large waves that are seen on large lakes, seas, or oceans.

    Fishing vessels are a subset of commercial vessels, but generally small in size and often subject to different regulations and classification. They can be categorized by several criteria: architecture, the type of fish they catch, the fishing method used, geographical origin, and technical features such as rigging. As of 2004, the world's fishing fleet consisted of some 4 million vessels.[40] Of these, 1.3 million were decked vessels with enclosed areas and the rest were open vessels.[40] Most decked vessels were mechanized, but two-thirds of the open vessels were traditional craft propelled by sails and oars.[40] More than 60% of all existing large fishing vessels[note 2] were built in Japan, Peru, the Russian Federation, Spain or the United States of America.[50]

    Special purpose vessels

    weather ship was a ship stationed in the ocean as a platform for surface and upper air meteorological observations for use in marine weather forecasting. Surface weather observations were taken hourly, and four radiosonde releases occurred daily.[51] It was also meant to aid in search and rescue operations and to support transatlantic flights.[51][52] Proposed as early as 1927 by the aviation community,[53] the establishment of weather ships proved to be so useful during World War II that the International Civil Aviation Organization (ICAO) established a global network of weather ships in 1948, with 13 to be supplied by the United States.[52] This number was eventually negotiated down to nine.[54]

    The weather ship crews were normally at sea for three weeks at a time, returning to port for 10-day stretches.[51] Weather ship observations proved to be helpful in wind and wave studies, as they did not avoid weather systems like other ships tended to for safety reasons.[55] They were also helpful in monitoring storms at sea, such as tropical cyclones.[56] The removal of a weather ship became a negative factor in forecasts leading up to the Great Storm of 1987.[57] Beginning in the 1970s, their role became largely superseded by weather buoys due to the ships' significant cost.[58] The agreement of the use of weather ships by

    The weather ship crews were normally at sea for three weeks at a time, returning to port for 10-day stretches.[51] Weather ship observations proved to be helpful in wind and wave studies, as they did not avoid weather systems like other ships tended to for safety reasons.[55] They were also helpful in monitoring storms at sea, such as tropical cyclones.[56] The removal of a weather ship became a negative factor in forecasts leading up to the Great Storm of 1987.[57] Beginning in the 1970s, their role became largely superseded by weather buoys due to the ships' significant cost.[58] The agreement of the use of weather ships by the international community ended in 1990. The last weather ship was Polarfront, known as weather station M ("Mike"), which was put out of operation on 1 January 2010. Weather observations from ships continue from a fleet of voluntary merchant vessels in routine commercial operation.

    Naval vessels are those used by a navy for military purposes. There have been many types of naval vessel. Modern naval vessels can be broken down into three categories: surface warships, submarines, and auxiliary ships.

    Modern warships are generally divided into seven main categories: aircraft carriers, cruisers, destroyers, frigates, corvettes, submarines and amphibious assault ships. The distinction between cruisers, destroyers, frigates, and corvettes is not rigorous; the same vessel may be described differently in different navies. Battleships were used during the Second World War and occasionally since then (the last battleships were removed from the U.S. Naval Vessel Register in March 2006), but were made obsolete by the use of carrier-borne aircraft and guided missiles.[59]

    Most military submarines are either attack submarines or ballistic missile submarines. Until the end of aircraft carriers, cruisers, destroyers, frigates, corvettes, submarines and amphibious assault ships. The distinction between cruisers, destroyers, frigates, and corvettes is not rigorous; the same vessel may be described differently in different navies. Battleships were used during the Second World War and occasionally since then (the last battleships were removed from the U.S. Naval Vessel Register in March 2006), but were made obsolete by the use of carrier-borne aircraft and guided missiles.[59]

    Most military submarines are either attack submarines or ballistic missile submarines. Until the end of World War II the primary role of the diesel/electric submarine was anti-ship warfare, inserting and removing covert agents and military forces, and intelligence-gathering. With the development of the homing torpedo, better sonar systems, and nuclear propulsion, submarines also became able to effectively hunt each other. The development of submarine-launched nuclear and cruise missiles gave submarines a substantial and long-ranged ability to attack both land and sea targets with a variety of weapons ranging from cluster munitions to nuclear weapons.

    Most navies also include many types of support and auxiliary vessel, such as minesweepers, patrol boats, offshore patrol vessels, replenishment ships, and hospital ships which are designated medical treatment facilities.[60]

    Fast combat vessels such as cruisers and destroyers usually have fine hulls to maximize speed and maneuverability.[61] They also usually have advanced marine electronics and communication systems, as well as weapons.

    Some components exist in vessels of any size and purpose. Every vessel has a hull of sorts. Every vessel has some sort of propulsion, whether it's a pole, an ox, or a nuclear reactor. Most vessels have some sort of steering system. Other characteristics are common, but not as universal, such as compartments, holds, a superstructure, and equipment such as anchors and winches.

    Hull

    For a ship to float, its weight must be less than that of the water displaced by the ship's hull.[62] There are many types of hulls, from logs lashed together to form a raft to the advanced hulls of America's Cup sailboats. A vessel may have a single hull (called a monohull design), two in the case of catamarans, or three in the case of trimarans. Vessels with more than three hulls are rare, but some experiments have been conducted with designs such as pentamarans. Multiple hulls are generally parallel to each other and connected by rigid arms.

    Hulls have several elements. The bow is the foremost part of the hull. Many ships feature a bulbous bow. The keel is at the very bottom of the hull, extending the entire length of the ship. The rear part of the hull is known as the stern, and many hulls have a flat back known as a transom. Common hull appendages include propellers for propulsion, rudders for steering, and stabilizers to quell a ship's rolling motion. Other hull features can be related to the vessel's work, such as fishing gear and sonar domes.

    Hulls are subject to various hydrostatic and hydrodynamic constraints. The key hydrostatic constraint is that it must be able to support the entire weight of the boat, and maintain stability even with often unevenly distributed weight. Hydrodynamic constraints include the ability to withstand shock waves, weather collisions and groundings.

    Older ships and pleasure

    Hulls have several elements. The bow is the foremost part of the hull. Many ships feature a bulbous bow. The keel is at the very bottom of the hull, extending the entire length of the ship. The rear part of the hull is known as the stern, and many hulls have a flat back known as a transom. Common hull appendages include propellers for propulsion, rudders for steering, and stabilizers to quell a ship's rolling motion. Other hull features can be related to the vessel's work, such as fishing gear and sonar domes.

    Hulls are subject to various hydrostatic and hydrodynamic constraints. The key hydrostatic constraint is that it must be able to support the entire weight of the boat, and maintain stability even with often unevenly distributed weight. Hydrodynamic constraints include the ability to withstand shock waves, weather collisions and groundings.

    Older ships and pleasure craft often have or had wooden hulls. Steel is used for most commercial vessels. Aluminium is frequently used for fast vessels, and composite materials are often found in sailboats and pleasure craft. Some ships have been made with concrete hulls.

    Propulsion systems for ships fall into three categories: human propulsion, sailing, and mechanical propulsion. Human propulsion includes rowing, which was used even on large galleys. Propulsion by sail generally consists of a sail hoisted on an erect mast, supported by stays and spars and controlled by ropes. Sail systems were the dominant form of propulsion until the 19th century. They are now generally used for recreation and competition, although experimental sail systems, such as the turbosails, rotorsails, and wingsails have been used on larger modern vessels for fuel savings.

    Mechanical propulsion systems generally consist of a motor or engine turning a propeller, or less frequently, an impeller or wave propulsion fins. Steam engines were first used for this purpose, but have mostly been replaced by two-stroke or four-stroke diesel engines, outboard motors, and gas turbine engines on faster ships. Nuclear reactors producing steam are used to propel warships and icebreakers, and there have been attempts to utilize them to power commercial vessels (see NS Savannah).

    In addition to traditional fixed and

    Mechanical propulsion systems generally consist of a motor or engine turning a propeller, or less frequently, an impeller or wave propulsion fins. Steam engines were first used for this purpose, but have mostly been replaced by two-stroke or four-stroke diesel engines, outboard motors, and gas turbine engines on faster ships. Nuclear reactors producing steam are used to propel warships and icebreakers, and there have been attempts to utilize them to power commercial vessels (see NS Savannah).

    In addition to traditional fixed and controllable pitch propellers there are many specialized variations, such as contra-rotating and nozzle-style propellers. Most vessels have a single propeller, but some large vessels may have up to four propellers supplemented with transverse thrusters for maneuvring at ports. The propeller is connected to the main engine via a propeller shaft and, in case of medium- and high-speed engines, a reduction gearbox. Some modern vessels have a diesel-electric powertrain in which the propeller is turned by an electric motor powered by the ship's generators.

    For ships with independent propulsion systems for each side, such as manual oars or some paddles,[note 3] steering systems may not be necessary. In most designs, such as boats propelled by engines or sails, a steering system becomes necessary. The most common is a rudder, a submerged plane located at the rear of the hull. Rudders are rotated to generate a lateral force which turns the boat. Rudders can be rotated by a tiller, manual wheels, or electro-hydraulic systems. Autopilot systems combine mechanical rudders with navigation systems. Ducted propellers are sometimes used for steering.

    Some propulsion systems are inherently steering systems. Examples include the outboard motor, the bow thruster, and the Z-drive.

    Holds, compartments, and the superstructure

    Larger boats and ships generally have multiple decks and compartments. Separate berthings and heads are found on sailboats over about 25 feet (7.6 m). Fishing boats and cargo ships typically have one or more cargo holds. Most larger vessels have an engine room, a galle

    Some propulsion systems are inherently steering systems. Examples include the outboard motor, the bow thruster, and the Z-drive.

    Larger boats and ships generally have multiple decks and compartments. Separate berthings and heads are found on sailboats over about 25 feet (7.6 m). Fishing boats and cargo ships typically have one or more cargo holds. Most larger vessels have an engine room, a galley, and various compartments for work. Tanks are used to store fuel, engine oil, and fresh water. Ballast tanks are equipped to change a ship's trim and modify its stability.

    Superstructures are found above the main deck. On sailboats, these are usually very low. On modern cargo ships, they are almost always located near the ship's stern. On passenger ships and warships, the superstructure generally extends far forward.

    Equipment

    Aerial view of the German battleship Schlesien, showing a 39° wake, characteristic of vessels passing through water.
    Vessels move along the three axes: 1. heave, 2. sway, 3. surge, 4. yaw, 5. pitch, 6. roll

    The advance of a vessel through water is resisted by the water. This resistance can be broken down into several components, the main ones being the friction of the water on the hull and wave making resistance. To reduce resistance and therefore increase the speed for a given power, it is necessary to reduce the wetted surface and use submerged hull shapes that produce low amplitude waves. To do so, high-speed vessels are often more slender, with fewer or smaller appendages. The friction of the water is also reduced by regular maintenance of the hull to remove the sea creatures and algae that accumulate there. Antifouling paint is commonly used to assist in this. Advanced designs such as the bulbous bow assist in decreasing wave resistance.

    A simple way of considering wave-making resistance is to look at the hull in relation to its wake. At speeds lower than the wave propagation speed, the wave rapidly dissipates to the sides. As the hull approaches the wave propagation speed, however, the wake at the bow begins to build up faster than it

    The advance of a vessel through water is resisted by the water. This resistance can be broken down into several components, the main ones being the friction of the water on the hull and wave making resistance. To reduce resistance and therefore increase the speed for a given power, it is necessary to reduce the wetted surface and use submerged hull shapes that produce low amplitude waves. To do so, high-speed vessels are often more slender, with fewer or smaller appendages. The friction of the water is also reduced by regular maintenance of the hull to remove the sea creatures and algae that accumulate there. Antifouling paint is commonly used to assist in this. Advanced designs such as the bulbous bow assist in decreasing wave resistance.

    A simple way of considering wave-making resistance is to look at the hull in relation to its wake. At speeds lower than the wave propagation speed, the wave rapidly dissipates to the sides. As the hull approaches the wave propagation speed, however, the wake at the bow begins to build up faster than it can dissipate, and so it grows in amplitude. Since the water is not able to "get out of the way of the hull fast enough", the hull, in essence, has to climb over or push through the bow wave. This results in an exponential increase in resistance with increasing speed.

    This hull speed is found by the formula:

    or, in metric units:

    amplitude. Since the water is not able to "get out of the way of the hull fast enough", the hull, in essence, has to climb over or push through the bow wave. This results in an exponential increase in resistance with increasing speed.

    This hull speed is found by the formula:

    or, in metric units:

    where

    where L is the length of the waterline in feet or meters.

    When the vessel exceeds a speed/length ratio of 0.94, it starts to outrun most of its bow wave, and the hull actually settles slightly in the water as it is now only supported by two wave peaks. As the vessel exceeds a speed/length ratio of 1.34, the hull speed, the wavelength is now longer than the hull, and the stern is no longer supported by the wake, causing the stern to squat, and the bow rise. The hull is now starting to climb its own bow wave, and resistance begins to increase at a very high rate. While it is possible to drive a displacement hull faster than a speed/length ratio of 1.34, it is prohibitively expensive to do so. Most large vessels operate at speed/length ratios well below that level, at speed/length ratios of under 1.0.

    For large projects with adequate funding, hydrodynamic resistance can be tested experimentally in a hull testing pool or using tools of computational fluid dynamics.

    Vessels are also subject to ocean surface waves and sea swell as well as effects of wind and weather. These movements can be stressful for passengers and equi

    When the vessel exceeds a speed/length ratio of 0.94, it starts to outrun most of its bow wave, and the hull actually settles slightly in the water as it is now only supported by two wave peaks. As the vessel exceeds a speed/length ratio of 1.34, the hull speed, the wavelength is now longer than the hull, and the stern is no longer supported by the wake, causing the stern to squat, and the bow rise. The hull is now starting to climb its own bow wave, and resistance begins to increase at a very high rate. While it is possible to drive a displacement hull faster than a speed/length ratio of 1.34, it is prohibitively expensive to do so. Most large vessels operate at speed/length ratios well below that level, at speed/length ratios of under 1.0.

    For large projects with adequate funding, hydrodynamic resistance can be tested experimentally in a hull testing pool or using tools of computational fluid dynamics.

    Vessels are also subject to ocean surface waves and sea swell as well as effects of wind and weather. These movements can be stressful for passengers and equipment, and must be controlled if possible. The rolling movement can be controlled, to an extent, by ballasting or by devices such as fin stabilizers. Pitching movement is more difficult to limit and can be dangerous if the bow submerges in the waves, a phenomenon called pounding. Sometimes, ships must change course or speed to stop violent rolling or pitching.

    How it has been convincingly shown in scientific studies of the 21st century,[63][64] controllability of some vessels decreases dramatically in some cases that are conditioned by effects of the bifurcation memory. This class of vessels includes ships with high manoeuvring capabilities, aircraft and controlled underwater vehicles designed to be unstable in steady-state motion that are interesting in terms of applications. These features must be considered in designing ships and in their control in critical situations.

    A ship will pass through several stages during its career. The first is usually an initial contract to build the ship, the details of which can vary widely based on relationships between the shipowners, operators, designers and the shipyard. Then, the design phase carried out by a naval architect. Then the ship is constructed in a shipyard. After construction, the vessel is launched and goes into service. Ships end their careers in a number of ways, ranging from shipwrecks to service as a museum ship to the scrapyard.

    Design

    A vessel's design starts with a specification, which a naval architect uses to create a project outline, assess required dimensions, and create a basic layout of spaces and a rough displacement. After this initial rough draft, the architect can create an initial hull design, a general profile and an initial overview of the ship's propulsion. At this stage, the designer can iterate on the ship's design, adding detail and refining the design at each stage.

    The designer will typically produce an overall plan, a general specification describing the peculiarities of the vessel, and construction blueprints to be used at the building site. Designs for larger or more complex vessels may also include sail plans, electrical schematics, and plumbing and ventilation plans.

    As environmental laws are becoming more strict, ship designers need to create their design in such a way that the ship, when it nears its end-of-term, can be disassembled or disposed easily and that waste is reduced to a minimum.

    Construction

    A ship launching at the Northern Shipyard in Gdańsk, Poland

    Ship construction takes place in a shipyard, and can last from a few months for a unit produced in series, to several years to reconstruct a wooden boat like the frigate Hermione, to more than 10 years for an aircraft carrier. During World War II, the need for cargo ships was so urgent that construction time for Liberty Ships<

    A vessel's design starts with a specification, which a naval architect uses to create a project outline, assess required dimensions, and create a basic layout of spaces and a rough displacement. After this initial rough draft, the architect can create an initial hull design, a general profile and an initial overview of the ship's propulsion. At this stage, the designer can iterate on the ship's design, adding detail and refining the design at each stage.

    The designer will typically produce an overall plan, a general specification describing the peculiarities of the vessel, and construction blueprints to be used at the building site. Designs for larger or more complex vessels may also include sail plans, electrical schematics, and plumbing and ventilation plans.

    As environmental laws are becoming more strict, ship designers need to create their design in such a way that the ship, when it

    The designer will typically produce an overall plan, a general specification describing the peculiarities of the vessel, and construction blueprints to be used at the building site. Designs for larger or more complex vessels may also include sail plans, electrical schematics, and plumbing and ventilation plans.

    As environmental laws are becoming more strict, ship designers need to create their design in such a way that the ship, when it nears its end-of-term, can be disassembled or disposed easily and that waste is reduced to a minimum.

    Ship construction takes place in a shipyard, and can last from a few months for a unit produced in series, to several years to reconstruct a wooden boat like the frigate Hermione, to more than 10 years for an aircraft carrier. During World War II, the need for cargo ships was so urgent that construction time for Liberty Ships went from initially eight months or longer, down to weeks or even days. Builders employed production line and prefabrication techniques such as those used in shipyards today.[65][66][67]

    Hull materials and vessel size play a large part in determining the method of construction. The hull of a mass-produced fiberglass sailboat is constructed from a mold, while the steel hull of a cargo ship is made from large sections welded together as they are built.

    Generally, construction starts with the hull, and on vessels over about 30 meters (98 ft), by the laying of the keel. This is done in a drydock or on land. Once the hull is assembled and painted, it is launched. The last stages, such as raising the superstructure and adding equipment and accommodation, can be done after the vessel is afloat.

    Once completed, the vessel is delivered to the customer. Ship launching is often a ceremony of some significance, and is usually when the vessel is formally named. A typical small rowboat can cost under US$100, $1,000 for a small speedboat, tens of thousands of dollars for a cruising sailboat, and about $2,000,000 for a Vendée Globe class sailboat. A 25 meters (82 ft) trawler may cost $2.5 million, and a 1,000-person-capacity high-speed passenger ferry can cost in the neighborhood of $50 million. A ship's cost partly depends on its complexity: a small, general cargo ship

    Hull materials and vessel size play a large part in determining the method of construction. The hull of a mass-produced fiberglass sailboat is constructed from a mold, while the steel hull of a cargo ship is made from large sections welded together as they are built.

    Generally, construction starts with the hull, and on vessels over about 30 meters (98 ft), by the laying of the keel. This is done in a drydock or on land. Once the hull is assembled and painted, it is launched. The last stages, such as raising the superstructure and adding equipment and accommodation, can be done after the vessel is afloat.

    Once completed, the vessel is delivered to the customer. Ship launching is often a ceremony of some significance, and is usually when the vessel is formally named. A typical small rowboat can cost under US$100, $1,000 for a small speedboat, tens of thousands of dollars for a cruising sailboat, and about $2,000,000 for a Vendée Globe class sailboat. A 25 meters (82 ft) trawler may cost $2.5 million, and a 1,000-person-capacity high-speed passenger ferry can cost in the neighborhood of $50 million. A ship's cost partly depends on its complexity: a small, general cargo ship will cost $20 million, a Panamax-sized bulk carrier around $35 million, a supertanker around $105 million and a large LNG carrier nearly $200 million. The most expensive ships generally are so because of the cost of embedded electronics: a Seawolf-class submarine costs around $2 billion, and an aircraft carrier goes for about $3.5 billion.

    Ships undergo nearly constant maintenance during their career, whether they be underway, pierside, or in some cases, in periods of reduced operating status between charters or shipping seasons.

    Most ships, however, require trips to special facilities such as a drydock at regular intervals. Tasks often done at drydock include removing biological growths on the hull, sandblasting and repainting the hull, and replacing sacrificial anodes used to protect submerged equipment from corrosion. Major repairs to the propulsion and steering systems as well as major electrical systems are also often performed at dry dock.

    Some vessels that sustain major damage at sea may be repaired at a facility equipped for major repairs, such as a shipyard. Ships may also be converted for a new purpose: oil tankers are often converted into floating production storage and offloading units.

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