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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 or capacity, its shape, or its ability to carry boats.
Small boats are typically used on inland waterways such as and , or in protected coastal areas. However, some boats (such as ) were intended for offshore use. In modern Navy terms, a boat is a vessel small enough to be carried aboard a ship.
Boats vary in proportion and construction methods with their intended purpose, available materials, or local traditions. have been used since prehistoric times and remain in use throughout the world for transportation, fishing, and sport. vary widely in style partly to match local conditions. Pleasure boat used in boating include ski boats, pontoon boats, and . may be used for vacationing or long-term residence. Lighters are used to move cargo to and from large ships unable to get close to shore. Lifeboats have rescue and safety functions.
Boats can be propelled by manpower (e.g. and pedalo), wind (e.g. ), and Inboard motor/Outboard motor (including gasoline engine, diesel engine, and electric motor).
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 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.
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 usethere 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. 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. (2025). 9781781593929, Pen and Sword Archaeology. ISBN 9781781593929
A number of large vessels are usually referred to as boats. are a prime example. Other types of large vessels which are traditionally called boats include lake freighter, , and . Though large enough to carry their own boats and heavy cargo, these vessels are designed for operation on inland or protected coastal waters.
The forward end of a boat is called the bow, the aft end the stern. Facing forward the right side is referred to as starboard and the left side as port.
By the mid-19th century, some boats had been built with iron or steel frames but still planked in wood. In 1855 ferro-cement boat construction was patented by the French, who coined the name "ferciment". This is a system by which a steel or iron wire framework is built in the shape of a boat's hull and covered over with cement. Reinforced with bulkheads and other internal structures it is strong but heavy, easily repaired, and, if sealed properly, will not leak or corrode.
As the forests of Britain and Europe continued to be over-harvested to supply the keels of larger wooden boats, and the Bessemer process ( 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,WH Mullins boat history, Salem Ohio 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.. as in the Iroqois catamaran or foam.
Strip-built 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.
As commercial vessels must be correctly loaded to be safe, and as the sea becomes less buoyant in brackish areas such as the Baltic Sea, the Plimsoll line was introduced to prevent overloading.
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