Boat
A boat is a watercraft of a large range of types and sizes, but generally smaller than a ship, which is distinguished by its larger size, shape, cargo or passenger capacity, or its ability to carry boats.
Small boats are typically found on inland waterways such as rivers and lakes, or in protected coastal areas. However, some boats, such as the whaleboat, were intended for use in an offshore environment. In modern naval terms, a boat is a vessel small enough to be carried aboard a ship.[1]
Boats vary in proportion and construction methods with their intended purpose, available materials, or local traditions.
Boats can be propelled by manpower (e.g.
).History
Differentiation from other prehistoric watercraft
The earliest watercraft are considered to have been rafts. These would have been used for voyages such as the settlement of Australia sometime between 50,000 and 60,000 years ago.
A boat differs from a raft by obtaining its buoyancy by having most of its structure exclude water with a waterproof layer, e.g. the planks of a wooden hull, the hide covering (or tarred canvas) of a currach. In contrast, a raft is buoyant because it joins together components that are themselves buoyant, for example, logs, bamboo poles, bundles of reeds, floats (such as inflated hides, sealed pottery containers or, in a modern context, empty oil drums). The key difference between a raft and a boat is that the former is a "flow through" structure, with waves able to pass up through it. Consequently, except for short river crossings, a raft is not a practical means of transport in colder regions of the world as the users would be at risk of hypothermia. Today that climatic limitation restricts rafts to between 40° north and 40° south, with, in the past, similar boundaries that have moved as the world's climate has varied.[2]: 11
Types
The earliest boats may have been either
Plank-built boats are considered, in most cases, to have developed from the logboat. There are examples of logboats that have been expanded: by deforming the hull under the influence of heat, by raising up the sides with added planks, or by splitting down the middle and adding a central plank to make it wider. (Some of these methods have been in quite recent use – there is no simple developmental sequence). The earliest known plank-built boats are from the Nile, dating to the third millennium BC. Outside Egypt, the next earliest are from England. The Ferriby boats are dated to the early part of the second millennium BC and the end of the third millennium.[8]: ch 4 Northern Europe; Mediterranean Region Plank-built boats require a level of woodworking technology that was first available in the neolithic with more complex versions only becoming achievable in the Bronze Age.[9]: 59
Types
Boats can be categorized by their means of propulsion. These divide into:
- Unpowered. This involves drifting with the tide or a river current.
- Powered by the crew-members on board, using oars, paddles or a punting pole or quant.
- Powered by sail.
- Towed – either by humans or animals from a river or canal bank (or in very shallow water, by walking on the sea or river bed) or by another vessel.
- Powered by machinery, such as internal combustion engines, steam engines or by batteries and an electric motor.: 33
Any one vessel may use more than one of these methods at different times or in combination.[10]
A number of large vessels are usually referred to as boats.
Terminology
The
The forward end of a boat is called the
Building materials
Until the mid-19th century, most boats were made of natural materials, primarily wood, although bark and animal skins were also used. Early boats include the birch bark canoe, the animal hide-covered kayak[13] and coracle and the dugout canoe made from a single log.
By the mid-19th century, some boats had been built with iron or steel frames but still planked in wood. In 1855
As the forests of Britain and Europe continued to be over-harvested to supply the keels of larger wooden boats, and the Bessemer process (patented in 1855) cheapened the cost of steel, steel ships and boats began to be more common. By the 1930s boats built entirely of steel from frames to plating were seen replacing wooden boats in many industrial uses and fishing fleets. Private recreational boats of steel remain uncommon. In 1895 WH Mullins produced steel boats of galvanized iron and by 1930 became the world's largest producer of pleasure boats.
Mullins also offered boats in aluminum from 1895 through 1899 and once again in the 1920s,[16] but it was not until the mid-20th century that aluminium gained widespread popularity. Though much more expensive than steel, aluminum alloys exist that do not corrode in salt water, allowing a similar load carrying capacity to steel at much less weight.
Around the mid-1960s, boats made of fiberglass (aka "glass fiber") became popular, especially for recreational boats. Fiberglass is also known as "GRP" (glass-reinforced plastic) in the UK, and "FRP" (for fiber-reinforced plastic) in the US. Fiberglass boats are strong and do not rust, corrode, or rot. Instead, they are susceptible to structural degradation from sunlight and extremes in temperature over their lifespan. Fiberglass structures can be made stiffer with sandwich panels, where the fiberglass encloses a lightweight core such as balsa[17] or foam.
Cold molding is a modern construction method, using wood as the structural component. In one cold molding process, very thin strips of wood are layered over a form. Each layer is coated with resin, followed by another directionally alternating layer laid on top. Subsequent layers may be stapled or otherwise mechanically fastened to the previous, or weighted or vacuum bagged to provide compression and stabilization until the resin sets. An alternative process uses thin sheets of plywood shaped over a disposable male mold, and coated with epoxy.
Propulsion
The most common means of boat propulsion are as follows:
- Engine
- Inboard motor
- Stern drive(Inboard/outboard)
- Outboard motor
- Paddle wheel
- Water jet (personal water craft)
- Fan (air boat)
- Man (paddling, setting poleetc.)
- Wind (sailing)
Buoyancy
A boat displaces its weight in water, regardless whether it is made of wood, steel, fiberglass, or even concrete. If weight is added to the boat, the volume of the hull drawn below the waterline will increase to keep the balance above and below the surface equal. Boats have a natural or designed level of buoyancy. Exceeding it will cause the boat first to ride lower in the water, second to take on water more readily than when properly loaded, and ultimately, if overloaded by any combination of structure, cargo, and water, sink.
As commercial vessels must be correctly loaded to be safe, and as the sea becomes less buoyant in brackish areas such as the Baltic, the Plimsoll line was introduced to prevent overloading.
European Union classification
Since 1998 all new leisure boats and barges built in Europe between 2.5m and 24m must comply with the EU's Recreational Craft Directive (RCD). The Directive establishes four categories that permit the allowable wind and wave conditions for vessels in each class:[18]
- Class A - the boat may safely navigate any waters.
- Class B - the boat is limited to offshore navigation. (Winds up to Force 8 & waves up to 4 metres)
- Class C - the boat is limited to inshore (coastal) navigation. (Winds up to Force 6 & waves up to 2 metres)
- Class D - the boat is limited to rivers, canals and small lakes. (Winds up to Force 4 & waves up to 0.5 metres)
Europe is the main producer of recreational boats (the second production in the world is located in Poland). European brands are known all over the world - in fact, these are the brands that created RCD and set the standard for shipyards around the world.[19]
See also
References
- ^ Cutler, Thomas J. (October 2017). "Bluejacket's Manual - Of Ships and Boats and . . ". Naval History Magazine. 31 (5).
- ^ a b
McGrail, Sean (2001). Boats of the World. Oxford, UK: Oxford University Press. ISBN 978-0-19-814468-7.
- ^ Van der Heide, G. D. (1974). Scheepsarcheologie in Nederland [Archeology of ships in the Netherlands]. Naarden: Strengholt. p. 507.
- ^ "World's oldest boat". Archived from the original on 2013-05-29. Retrieved 2013-11-08.
- ^ "Oldest Boat Unearthed". China.org.cn. Archived from the original on 2009-01-02. Retrieved 2008-05-05.
- ISBN 978-0-19-814468-7.
- ^ "8,000-year-old dug out canoe on show in Italy". Stone Pages Archeo News. Retrieved 2008-08-17.
- ^ ISBN 9781782970453.
- ISBN 9781781593929.
- ISBN 9781781593929.
- ^ Chief of Naval Operations (March 2001). "The Saga of the Submarine: Early Years to the Beginning of Nuclear Power". United States Navy. Archived from the original on January 14, 2009. Retrieved 2008-10-03.
- ^ Williams, Charles Frederic (1895), "Vessel", in Merrill, John Houston; Williams, Charles Frederic; Michie, Thomas Johnson; Garland, David Shephard (eds.), Utmost care to Watercourses, The American and English Encyclopædia of Law, vol. 28, Edward Thompson Company, p. 440
- ISBN 9780316042918.
- OCLC 858712.
- ^ "Ferrocement – The World of Ferroboats". Retrieved 2022-12-26.
- ^ WH Mullins boat history, Salem Ohio
- Iroqois catamaran
- ISBN 9780953281954
- ^ "Cabin boats manufactured in Europe". theYachters.com.
External links
- University of Washington Libraries Digital Collections – Freshwater and Marine Image Bank (enter search term "vessels" for images of boats and vessels)