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Canoe
A canoe is a relatively small boat, typically human-powered, but also commonly sailed. Canoes are pointed at both ends and usually open on top.
In its human-powered form, the canoe is propelled by the use of paddles, with the number of paddlers depending on the size of canoe. Paddlers face in the direction of travel, either seated on supports in the hull, or kneeling directly upon the hull. In this way paddling a canoe can be contrasted with rowing, where the rowers face away from the direction of travel. Paddles may be single-bladed or double-bladed.
Sailing Canoes (see Canoe Sailing) are propelled by means of a variety of sailing rigs. Common classes of modern sailing canoes include the 5sqm and the International 10sqm Sailing canoes. The latter is otherwise known as the International Canoe, and is one of the fastest and oldest competitively sailed boat classes in the western world.

Ambiguity over the word Canoe
Confusingly, the sport of canoeing, organised at the international level by the International Canoe Federation, uses the word canoe to cover both canoes as defined here, and kayaks (see below for a brief description of the differences between a kayak and a canoe). In fact, the sport of canoe polo is exclusively played in kayaks. This confusing use of canoe to generically cover both canoes and kayaks is not so common in North American usage, but is common in Britain, Australia and presumably many parts of the world, both in sporting jargon and in colloquial speech. In these circumstances, the canoe as defined here is sometimes referred to as an open, Canadian, or Indian canoe, though these terms have their own ambiguities.
A 'canoe' in this ambiguous sense is a paddled vessel in which the user faces the direction of travel.

Design and construction

Canoe materials

Canoeing on the Concord River.Early canoes were wooden, often simply hollowed-out tree trunks. This technology is still practiced in some parts of the world.
Modern wooden canoes are typically strip-built by woodworking craftsmen. Such canoes can be very functional, lightweight, and strong, and are frequently quite beautiful works of art.
Birch bark and a mixture of tar and tree sap were used by the American Indians of temperate North America, and later became the standard form of transport for Voyageurs of the fur trade.
Wood-and-Canvas canoes are made by fastening an external canvas shell to a wooden hull. These use of canvas for this purpose was invented by Union scouts during the United States Civil War.
Aluminum canoes were first made by the Grumman company in 1944, when demand for airplanes for World War II began to drop off. Aluminum allowed a lighter and much stronger construction than contemporary wood technology. However, aluminium is denser than water, so a capsized aluminium canoe will sink unless the ends are filled with flotation devices.
Royalex is a modern composite material that makes an extremely flexible and durable hull. Royalex canoes have been known, after being wrapped around a rock, to be popped back into their original shapes with minimal creasing of the hull.
Composites of fiberglass and Kevlar are also used for modern canoe construction.
Depending on the intended use of a canoe, the various kinds have different advantages. For example, a canvas canoe is more fragile than an aluminum canoe, and thus less suitable for use in rough water; but it is quieter, and so better for observing wildlife. However, canoes made of natural materials require regular maintenance, and are lacking in durability.

Hull design considerations
A rounded-bottom canoe exhibits poor resistance to small degrees of tilt, but is difficult to overturn (i.e. its initial stability is lacking, but its final stability is good). A flat-bottomed canoe has excellent initial stability, but if tilted beyond a threshold, becomes unstable and will capsize. Round-bottomed designs are also able to go over obstructions much more easily, due to a small area of contact with the obstruction, though they do have a slightly greater draft. Many canoes are symmetrical about the centerline, but some advanced designs are asymmetrical.
Keels on canoes may slightly increase the ability to 'track' in a straight line with crosswind, but decrease the ability to turn quickly to avoid an obstacle. "Vee"-bottom canoes have an integrated keel-like protrusion of the hull, which increases initial stability. Some sort of keel is beneficial when traveling on open water with crosswinds, but the associated increase in draft is undesirable for whitewater.
Keels don't really appreciably help canoes go in a straight line. Canoes are displacement craft. Their hull, moving through the water, is much larger than the keel alone, and has considerably more effect on a canoes path through the water. In aluminum canoes, keels are manufacturing artifacts, where two halves of a hull are joined. In wood-and-canvas canoes, keels are rub-strips to protect the boat from rocks and as they are pulled up on shore. Plastic canoes feature keels for stiffening the hull and allowing internal tubular framing to be flush with the sole of the canoe. Hull shape, particularly the manner in which the hull flows to the bow and stern, along with paddling technique , determine how well (or not) a canoe will track.
Rounded-end canoes are able to turn easily. Angled-end canoes are somewhat resistant to turning, but have greater tracking ability. Tall ends serve little purpose other than catching the wind.
Canoe hulls are generally open on top. However, slalom canoes are closed in with a spraydeck, like many kayaks.

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