Sunday, June 23, 2013

Boat

    A boat is a watercraft of any size designed to float or plane, to provide passage across water. Usually this water will be inland (lakes) or in protected coastal areas. However, boats such as the whaleboat were designed to be operated from a ship in an offshore environment. In naval 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.

    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 belog boats. The oldest boats to be found by archaeological excavation are log boats from around 7,000–10,000 years ago. The oldest recovered boat in the world is the Pesse canoe; it is a dug out or hollowed tree trunk from a Pinus sylvestris. It was constructed somewhere between 8200 and 7600 BC. 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 reed boat has been found in Kuwait. Boats were used between 4000 and 3000 BC in Sumer, ancient Egypt and in the Indian Ocean.

     Boats played a very important part in the commerce between the Indus Valley Civilization and Mesopotamia. Evidence of varying models of boats has also been discovered in various Indus Valley sites. The Uru wooden big boat was made in Beypore a village in south Calicut, Kerala, in southwestern India. 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 and which has transportation capacity of 400 tonnes.


     Several key components make up the main structure of most boats. The hull is the main structural component of the boat which actually provides buoyancy for the boat. Also there is the gunnel which is the sides of the boat. They offer protection from the water and makes the boat harder to sink. 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 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.

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