Boat - AbsoluteAstronomy.com

A boat is a watercraft

Watercraft

A watercraft is a vessel or craft designed to move across or through water. The name is derived from the term "craft" which was used to describe all types of water going vessels...

of any size designed to float or plane

Planing (sailing)

Planing is the mode of operation for a waterborne craft in which its weight is predominantly supported by hydrodynamic lift, rather than hydrostatic lift .-History:...

, to provide passage across water. Usually this water will be inland (lake

Lake

A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...

s) or in protected coastal areas. However, boats such as the whaleboat

Whaleboat

A whaleboat is a type of open boat that is relatively narrow and pointed at both ends, enabling it to move either forwards or backwards equally well. It was originally developed for whaling, and later became popular for work along beaches, since it does not need to be turned around for beaching or...

were designed to be operated from a ship

Ship

Since the end of the age of sail a ship has been any large buoyant marine vessel. Ships are generally distinguished from boats based on size and cargo or passenger capacity. Ships are used on lakes, seas, and rivers for a variety of activities, such as the transport of people or goods, fishing,...

in an offshore environment. In naval

Navy

A navy is the branch of a nation's armed forces principally designated for naval and amphibious warfare; namely, lake- or ocean-borne combat operations and related functions...

terms, a boat is a vessel small enough to be carried aboard another vessel (a ship). Another less restrictive definition is a vessel that can be lifted out of the water. Strictly speaking and uniquely a submarine

Submarine

A submarine is a watercraft capable of independent operation below the surface of the water. It differs from a submersible, which has more limited underwater capability...

is a boat as defined by the Royal Navy

Royal Navy

The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

. Some boats too large for the naval definition include the Great Lakes freighter

Lake freighter

Lake freighters, or Lakers, are bulk carrier vessels that ply the Great Lakes. The best known was the , the most recent and largest major vessel to be wrecked on the Lakes. These vessels are traditionally called boats, although classified as ships. In the mid-20th century, 300 lakers worked the...

, riverboat

Riverboat

A riverboat is a ship built boat designed for inland navigation on lakes, rivers, and artificial waterways. They are generally equipped and outfitted as work boats in one of the carrying trades, for freight or people transport, including luxury units constructed for entertainment enterprises, such...

, narrowboat

Narrowboat

A narrowboat or narrow boat is a boat of a distinctive design, made to fit the narrow canals of Great Britain.In the context of British Inland Waterways, "narrow boat" refers to the original working boats built in the 18th, 19th, and 20th centuries for carrying goods on the narrow canals...

and ferry

Ferry

A ferry is a form of transportation, usually a boat, but sometimes a ship, used to carry primarily passengers, and sometimes vehicles and cargo as well, across a body of water. Most ferries operate on regular, frequent, return services...

boat. The term armed boat, used primarily by English speaking naval forces, referred to any boat carrying either a cannon

Cannon

A cannon is any piece of artillery that uses gunpowder or other usually explosive-based propellents to launch a projectile. Cannon vary in caliber, range, mobility, rate of fire, angle of fire, and firepower; different forms of cannon combine and balance these attributes in varying degrees,...

or armed occupants, such as marines.

History

Boats have served as short-distance transportation since early times. Circumstantial evidence, such as the early settlement of Australia over 40,000 years ago, and findings in Crete dated 130,000 years ago, suggests that boats have been used since ancient times. The earliest boats have been predicted to be logboats

Dugout (boat)

A dugout or dugout canoe is a boat made from a hollowed tree trunk. Other names for this type of boat are logboat and monoxylon. Monoxylon is Greek -- mono- + ξύλον xylon -- and is mostly used in classic Greek texts. In Germany they are called einbaum )...

. The oldest boats to be found by archaeological excavation are logboats from around 7,000–10,000 years ago. The oldest recovered boat in the world is the canoe of Pesse; it is a dugout

Dugout (boat)

or hollowed tree trunk from a Pinus sylvestris. It was constructed somewhere between 8200 and 7600 B.C. This canoe is exhibited in the Drents Museum in Assen, Netherlands; other very old dugout boats have been recovered.
A 7,000 year-old seagoing boat made from reeds

Reed boat

Reed boats and rafts, along with dugout canoes and other rafts, are among the oldest known types of boats. Often used as traditional fishing boats, they are still used in a few places around the world, though they have generally been replaced with planked boats. Reed boats can be distinguished from...

and tar has been found in Kuwait

Kuwait

The State of Kuwait is a sovereign Arab state situated in the north-east of the Arabian Peninsula in Western Asia. It is bordered by Saudi Arabia to the south at Khafji, and Iraq to the north at Basra. It lies on the north-western shore of the Persian Gulf. The name Kuwait is derived from the...

.

Boats were used between 4000 BCE and 3000 BCE in Sumer

Sumer

Sumer was a civilization and historical region in southern Mesopotamia, modern Iraq during the Chalcolithic and Early Bronze Age....

, ancient Egypt

Ancient Egypt

Ancient Egypt was an ancient civilization of Northeastern Africa, concentrated along the lower reaches of the Nile River in what is now the modern country of Egypt. Egyptian civilization coalesced around 3150 BC with the political unification of Upper and Lower Egypt under the first pharaoh...

and in the Indian Ocean

Indian Ocean

The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...

.

Boats played a very important part in the commerce between the Indus Valley Civilization

Indus Valley Civilization

The Indus Valley Civilization was a Bronze Age civilization that was located in the northwestern region of the Indian subcontinent, consisting of what is now mainly modern-day Pakistan and northwest India...

and Mesopotamia

Mesopotamia

Mesopotamia is a toponym for the area of the Tigris–Euphrates river system, largely corresponding to modern-day Iraq, northeastern Syria, southeastern Turkey and southwestern Iran.Widely considered to be the cradle of civilization, Bronze Age Mesopotamia included Sumer and the...

. Evidence of varying models of boats has also been discovered in various Indus Valley sites.
The Uru wooden big boat made in Beypore

Beypore

Beypore or Beypur is a ancient port town and part of Calicut municipal corporation in Kozhikode district in the state of Kerala, India. The place was formerly known as Vaypura / Vadaparappanad. Tippu Sultan named the town “Sultan Pattanam”.This place also has a marina and a beautiful beach...

a village in south Calicut, Kerala

Kerala

or Keralam is an Indian state located on the Malabar coast of south-west India. It was created on 1 November 1956 by the States Reorganisation Act by combining various Malayalam speaking regions....

, in southwestern India

India

India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

. These have been used by the Arabs and Greeks since ancient times as trading vessels. This mammoth wooden ship was constructed using teak, without any iron or blueprints which has transportation capacity of 400 tonnes.

The accounts of historians Herodotus

Herodotus

Herodotus was an ancient Greek historian who was born in Halicarnassus, Caria and lived in the 5th century BC . He has been called the "Father of History", and was the first historian known to collect his materials systematically, test their accuracy to a certain extent and arrange them in a...

, Pliny the Elder

Pliny the Elder

Gaius Plinius Secundus , better known as Pliny the Elder, was a Roman author, naturalist, and natural philosopher, as well as naval and army commander of the early Roman Empire, and personal friend of the emperor Vespasian...

, and Strabo

Strabo

Strabo, also written Strabon was a Greek historian, geographer and philosopher.-Life:Strabo was born to an affluent family from Amaseia in Pontus , a city which he said was situated the approximate equivalent of 75 km from the Black Sea...

suggest that boats were being used for commerce and traveling.

Types

Boats can be categorized into three types:

Unpowered or human-powered boats. (Unpowered boats include raft
Raft
A raft is any flat structure for support or transportation over water. It is the most basic of boat design, characterized by the absence of a hull...

s and floats meant for one-way downstream travel. Human-powered boats include canoe
Canoe
A canoe or Canadian canoe is a small narrow boat, typically human-powered, though it may also be powered by sails or small electric or gas motors. Canoes are usually pointed at both bow and stern and are normally open on top, but can be decked over A canoe (North American English) or Canadian...

s, kayak
Kayak
A kayak is a small, relatively narrow, human-powered boat primarily designed to be manually propelled by means of a double blade paddle.The traditional kayak has a covered deck and one or more cockpits, each seating one paddler...

s, gondola
Gondola
The gondola is a traditional, flat-bottomed Venetian rowing boat, well suited to the conditions of the Venetian Lagoon. For centuries gondolas were the chief means of transportation and most common watercraft within Venice. In modern times the iconic boats still have a role in public transport in...

s and boats propelled by poles like a punt
Punt (boat)
A punt is a flat-bottomed boat with a square-cut bow, designed for use in small rivers or other shallow water. Punting refers to boating in a punt. The punter generally propels the punt by pushing against the river bed with a pole...

.)
Sailing boats
Sailing ship
The term sailing ship is now used to refer to any large wind-powered vessel. In technical terms, a ship was a sailing vessel with a specific rig of at least three masts, square rigged on all of them, making the sailing adjective redundant. In popular usage "ship" became associated with all large...

, which are boats propelled solely by means of sail
Sail
A sail is any type of surface intended to move a vessel, vehicle or rotor by being placed in a wind—in essence a propulsion wing. Sails are used in sailing.-History of sails:...

s.
Motorboat
Motorboat
A motorboat is a boat which is powered by an engine. Some motorboats are fitted with inboard engines, others have an outboard motor installed on the rear, containing the internal combustion engine, the gearbox and the propeller in one portable unit.An inboard/outboard contains a hybrid of a...

s, which are boats propelled by mechanical means, such as engines.

Parts and terminology

Several key components make up the main structure of most boats. The hull

Hull (watercraft)

A hull is the watertight body of a ship or boat. Above the hull is the superstructure and/or deckhouse, where present. The line where the hull meets the water surface is called the waterline.The structure of the hull varies depending on the vessel type...

is the main structural component of the boat which actually provides buoyancy for the boat. The roughly horizontal, but chambered structures spanning the hull of the boat are referred to as the deck. In a ship there are often several decks, but a boat is unlikely to have more than one, if any at all. Above the deck are the superstructures. The underside of a deck is the deck head.

An enclosed space on a boat is referred to as a cabin. Several structures make up a cabin: the similar but usually lighter structure which spans a raised cabin is a coach-roof. The "floor" of a cabin is properly known as the sole, but is more likely to be called the floor (a floor is properly, a structural member which ties a frame to the keelson and keel). The vertical surfaces dividing the internal space are bulkheads.

The keel

Keel

In boats and ships, keel can refer to either of two parts: a structural element, or a hydrodynamic element. These parts overlap. As the laying down of the keel is the initial step in construction of a ship, in British and American shipbuilding traditions the construction is dated from this event...

is a lengthwise structural member to which the frames are fixed (sometimes referred to as a backbone).

The front (or forward end) of a boat is called the bow. Boats of earlier times often featured a figurehead protruding from the front of the bows. The rear (or aft end) of the boat is called the stern. The right side (facing forward) is starboard and the left side is port.

Building materials

Until the mid 19th century most boats were of all natural materials; primarily wood although reed

Reed (plant)

Reed is a generic polyphyletic botanical term used to describe numerous tall, grass-like plants of wet places, which are the namesake vegetation of reed beds...

, bark and animal skins were also used. Early boats include the bound-reed style of boat seen in Ancient Egypt, the birch bark

Birch bark

Birch bark or birchbark is the bark of several Eurasian and North American birch trees of the genus Betula.The strong and water-resistant cardboard-like bark can be easily cut, bent, and sewn, which made it a valuable building, crafting, and writing material, since pre-historic times...

canoe

Canoe

A canoe or Canadian canoe is a small narrow boat, typically human-powered, though it may also be powered by sails or small electric or gas motors. Canoes are usually pointed at both bow and stern and are normally open on top, but can be decked over A canoe (North American English) or Canadian...

, the animal hide-covered kayak

Kayak

A kayak is a small, relatively narrow, human-powered boat primarily designed to be manually propelled by means of a double blade paddle.The traditional kayak has a covered deck and one or more cockpits, each seating one paddler...

and coracle

Coracle

The coracle is a small, lightweight boat of the sort traditionally used in Wales but also in parts of Western and South Western England, Ireland , and Scotland ; the word is also used of similar boats found in India, Vietnam, Iraq and Tibet...

and the dugout canoe made from a single log. By the mid 19th century, many 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. They called it 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 (trowell

Trowell

Trowell is a village and civil parish in Nottinghamshire, England. It lies a few miles west of Nottingham, in the borough of Broxtowe on the border with Derbyshire. According to the 2001 census it had a population of 2,568....

ed) over with cement. Reinforced with bulkheads and other internal structure, it is strong but heavy, easily repaired, and, if sealed properly, will not leak or corrode. These materials and methods were copied all over the world, and have faded in and out of popularity to the present. As the forests of Britain and Europe continued to be over-harvested to supply the keels of larger wooden boats, and the Bessemer process

Bessemer process

The Bessemer process was the first inexpensive industrial process for the mass-production of steel from molten pig iron. The process is named after its inventor, Henry Bessemer, who took out a patent on the process in 1855. The process was independently discovered in 1851 by William Kelly...

(patent

Patent

A patent is a form of intellectual property. It consists of a set of exclusive rights granted by a sovereign state to an inventor or their assignee for a limited period of time in exchange for the public disclosure of an invention....

ed in 1855) cheapened the cost of steel, steel ships and boats began to be more common. By the 1930s boats built of all steel from frames to plating were seen replacing wooden boats in many industrial uses, even the fishing fleets. Private recreational boats in steel are uncommon. In the mid 20th century aluminium

Aluminium

Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....

gained popularity. Though much more expensive than steel, there are now aluminium alloys available that will not corrode in salt water, and an aluminium boat built to similar load carrying standards could be built lighter than steel.

Around the mid 1960s, boats made of glass-reinforced plastic

Glass-reinforced plastic

Fiberglass , is a fiber reinforced polymer made of a plastic matrix reinforced by fine fibers of glass. It is also known as GFK ....

, more commonly known as fibreglass, became popular, especially for recreational boats. The United States Coast Guard

United States Coast Guard

The United States Coast Guard is a branch of the United States Armed Forces and one of the seven U.S. uniformed services. The Coast Guard is a maritime, military, multi-mission service unique among the military branches for having a maritime law enforcement mission and a federal regulatory agency...

refers to such boats as 'FRP' (for Fibre Reinforced Plastic) boats.

Fibreglass boats are extremely strong, and do not rust (iron oxide), corrode, or rot. They are, however susceptible to structural degradation from sunlight and extremes in temperature over their lifespan. Fibreglass provides structural strength, especially when long woven strands are laid, sometimes from bow to stern, and then soaked in epoxy or polyester resin to form the hull of the boat. Whether hand laid or built in a mould, FRP boats usually have an outer coating of gelcoat which is a thin solid colored layer of polyester resin that adds no structural strength, but does create a smooth surface which can be buffed to a high shine and also acts as a protective layer against sunlight. FRP structures can be made stiffer with sandwich panels, where the FRP encloses a lightweight core such as balsa or foam. Cored FRP is most often found in decking which helps keep down weight that will be carried above the waterline. The addition of wood makes the cored structure of the boat susceptible to rotting which puts a greater emphasis on not allowing damaged sandwich structures to go unrepaired. Plastic based foam cores are less vulnerable. The phrase 'advanced composites' in FRP construction may indicate the addition of carbon fibre, kevlar(tm) or other similar materials, but it may also indicate other methods designed to introduce less expensive and, by at least one yacht surveyor's eyewitness accounts, less structurally sound materials.

Cold molding is similar to FRP in as much as it involves the use of epoxy or polyester resins, but the structural component is wood instead of fibreglass. In cold moulding very thin strips of wood are laid over a form or mould in layers. This layer is then coated with resin and another directionally alternating layer is laid on top. In some processes the subsequent layers are stapled or otherwise mechanically fastened to the previous layers, but in other processes the layers are weighted or even vacuum bagged to hold layers together while the resin sets. Layers are built up thus to create the required thickness of hull.

People have even made their own boats or watercraft out of materials such as foam or plastic, but most homebuilts today are built of plywood and either painted or covered in a layer of fibreglass and resin.

Propulsion

The most common means are:

human power (rowing
Watercraft rowing
Watercraft rowing is the act of propelling a boat using the motion of oars in the water. The difference between paddling and rowing is that with rowing the oars have a mechanical connection with the boat whereas with paddling the paddles are hand-held with no mechanical connection.This article...

, paddling
Watercraft paddling
Paddling with regard to watercraft is the act of manually propelling or navigating a small boat using a blade that is joined to a shaft, known as paddle, in the water. The paddle is also used to steer the vessel and may either be a single bladed or double bladed...

, setting pole
Setting pole
A setting pole is a pole, handled by a single individual, made to move watercraft by pushing the craft in the desired direction. Because it is a pushing tool, it is generally used from the stern of the craft....

and so on.)
wind power (sailing)
Motor powered screws
Propeller
A propeller is a type of fan that transmits power by converting rotational motion into thrust. A pressure difference is produced between the forward and rear surfaces of the airfoil-shaped blade, and a fluid is accelerated behind the blade. Propeller dynamics can be modeled by both Bernoulli's...
- Inboard
  Inboard motor
  An inboard motor is a marine propulsion system for boats. As opposed to an outboard motor where an engine is mounted outside of the hull of the craft, an inboard motor is an engine enclosed within the hull of the boat, usually connected to a propulsion screw by adriveshaft.-History:The first...
  - internal combustion (gasoline, diesel, heavy fuel oil)
  - steam (coal, fuel oil
    Fuel oil
    Fuel oil is a fraction obtained from petroleum distillation, either as a distillate or a residue. Broadly speaking, fuel oil is any liquid petroleum product that is burned in a furnace or boiler for the generation of heat or used in an engine for the generation of power, except oils having a flash...
    
    )
  - nuclear (for submarines and large naval ships)
- Inboard/Outboard (sterndrive)
  - gasoline
  - diesel
    Diesel engine
    A diesel engine is an internal combustion engine that uses the heat of compression to initiate ignition to burn the fuel, which is injected into the combustion chamber...
- Outboard
  Outboard motor
  An outboard motor is a propulsion system for boats, consisting of a self-contained unit that includes engine, gearbox and propeller or jet drive, designed to be affixed to the outside of the transom and are the most common motorized method of propelling small watercraft...
  - electric
- paddle wheel
  Paddle steamer
  A paddle steamer is a steamship or riverboat, powered by a steam engine, using paddle wheels to propel it through the water. In antiquity, Paddle wheelers followed the development of poles, oars and sails, where the first uses were wheelers driven by animals or humans...
- Water Jet (Personal water craft
  Personal water craft
  A personal water craft , also called water scooter, is a recreational watercraft that the rider rides or stands on, rather than inside of, as in a boat....
  
  , Jetboat
  Jetboat
  A jetboat is a boat propelled by a jet of water ejected from the back of the craft. Unlike a powerboat or motorboat that uses a propeller in the water below or behind the boat, a jetboat draws the water from under the boat into a pump inside the boat, then expels it through a nozzle at the...
  
  )
- Air Fans (Hovercraft
  Hovercraft
  A hovercraft is a craft capable of traveling over surfaces while supported by a cushion of slow moving, high-pressure air which is ejected against the surface below and contained within a "skirt." Although supported by air, a hovercraft is not considered an aircraft.Hovercraft are used throughout...
  
  , Air boat
  Air boat
  An airboat, also known as a fanboat, is a flat-bottomed vessel propelled in a forward direction by an aircraft-type propeller and powered by either an aircraft or automotive engine. Airboats are a very popular means of transportation in the Florida Everglades, parts of the Indian River Lagoon, the...
  
  )

Track-driven propulsion

An early uncommon means of boat propulsion was referred to as the water caterpillar which is similar in construction to paddles on a conveyor belt and preceded the development of tracked vehicles such as military tanks and earth moving equipment. A series of paddles on chains moved along the bottom of the boat to propel it over the water.

The first water caterpillar was developed by Desblancs in 1782 and propelled by a steam engine. In the United States the first water caterpillar was patented in 1839 by William Leavenworth of New York.

Buoyancy

A floating boat displaces

Displacement (fluid)

In fluid mechanics, displacement occurs when an object is immersed in a fluid, pushing it out of the way and taking its place. The volume of the fluid displaced can then be measured, as in the illustration, and from this the volume of the immersed object can be deduced .An object that sinks...

its weight in water. The material of the boat hull may be denser than water, but if this is the case then it forms only the outer layer. If the boat floats, the mass of the boat (plus contents) as a whole divided by the volume below the waterline is equal to the density

Density

The mass density or density of a material is defined as its mass per unit volume. The symbol most often used for density is ρ . In some cases , density is also defined as its weight per unit volume; although, this quantity is more properly called specific weight...

of water (1 kg/l). If weight is added to the boat, the volume below the waterline will increase to keep the weight balance equal, and so the boat sinks a little to compensate.

External links

PDRacer - The Easiest Sailboat In the World To Build
Sailboats database: sailboat data sheets all over the world
University of Washington Libraries Digital Collections -- http://content.lib.washington.edu/cgi-bin/queryresults.exe?CISOOP=adv&CISORESTMP=%2Fsite-templates%2Fsearch_results-sub.html&CISOVIEWTMP=%2Fsite-templates%2Fitem_viewer.html&CISOMODE=thumb&CISOGRID=thumbnail%2CA%2C1%3Btitle%2CA%2C1%3Bsubjec%2CA%2C0%3Bdescri%2C200%2C0%3B0%2CA%2C0%3B10&CISOBIB=title%2CA%2C1%2CN%3Bsubjec%2CA%2C0%2CN%3Bdescri%2CK%2C0%2CN%3B0%2CA%2C0%2CN%3B0%2CA%2C0%2CN%3B10&CISOTHUMB=3%2C5&CISOTITLE=10&CISOPARM=%2Ffishimages%3Asubjec%3Avessels&x=51&y=5Freshwater and Marine Image Bank -- Vessels] - images of boats and vessels

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