Wednesday, February 17, 2010

History



Kayaks (Inuktitut: qajaq, Inuktitut syllabics: ᖃᔭᖅ) were originally developed by indigenous Arctic people, who used the boats to hunt on inland lakes, rivers and coastal waters of the Arctic Ocean, North Atlantic, Bering Sea and North Pacific oceans. These first kayaks were constructed from stitched animal skins such as seal stretched over a wooden frame made from driftwood, since many of their habitats were treeless. Kayaks are at least 4,000 years old.[1] The oldest existing kayaks are exhibited in the North America department of the State Museum of Ethnology in Munich.[2]

Though the term "kayak" is now used for this class of boat, native people made many types of boat for different purposes. The baidarka, developed by indigenous cultures in Alaska, was also made in double or triple cockpit designs, for hunting and transporting passengers or goods. An umiak is a large open sea canoe, ranging from 17 feet (5.2 m) to 30 feet (9.1 m), made with seal skins and wood. It was originally paddled with single-bladed paddles and typically had more than one paddler.

The word "kayak" means "man's boat" or "hunter's boat", and native kayaks were a personal craft, each built by the man who used it (with assistance from his wife, who sewed the skins) fitting his size for maximum maneuverability. A special skin jacket, Tuilik, was then laced to the kayak, creating a waterproof seal. This enabled the eskimo roll to become the preferred method of regaining posture after turning upside down (kayakers consider "capsize" to refer to separation of paddler and vessel) especially as few Eskimos could swim; their waters are too cold for a swimmer to survive for long.[3]

The modern version of a tuilik is a spraydeck made of waterproof synthetic stretchy enough to fit tightly around the cockpit rim and body of the kayaker, which can however be released rapidly from the cockpit to permit easy exit.

The builder used found materials to create a kayak measured to his own body. For example: the length was typically three times the span of his outstretched arms. The width at the cockpit was the width of the builder's hips plus two fists (and sometimes less). The typical depth was his fist plus the outstretched thumb (hitch hiker). Thus typical dimensions were about 17 feet (5.2 m) long by 20–22 inches (51–56 cm) wide by 7 inches (180 mm) deep. This measurement system confounded early European explorers who tried to duplicate the kayak because each kayak was a little different.

Traditional kayaks encompass three types of boat: Baidarkas, from the Alaskan & Aleutian seas, the oldest design, whose rounded shape and numerous chines give them an almost Blimp-like appearance; West Greenland kayaks, with fewer chines and a more angular shape, with gunwales rising to a point at the bow and stern; and East Greenland kayaks that appear similar to the West Greenland style, but often fit more snugly to the paddler and possess a steeper angle between gunwale and stem which lend maneuverability.

Most of the Eskimo peoples from the Aleutian Islands eastward to Greenland relied on the kayak for hunting a variety of prey — primarily seals, though whales and caribou were important in some areas. Skin on frame kayaks are still being used for hunting by Inuit people in Greenland. In other parts of the world homebuilders are continuing the tradition of skin on frame kayaks albeit with modern skins of canvas or synthetic fabric.

Contemporary kayaks trace their origins primarily to the native boats of Alaska, northern Canada, and Southwest Greenland. Wooden kayaks and fabric kayaks on wooden frames (such as the Klepper) dominated the market up until 1950s, when fiberglass boats were first introduced. Rotomolded plastic kayaks first appeared in 1973. The development of plastic kayaks arguably initiated the development of freestyle kayaking as we see it today, since plastic boats could be made smaller, stronger and more resilient than those made of other materials.

Introduction

A kayak is a small human-powered boat that traditionally has a covered deck, and one or more cockpits, each seating one paddler who strokes a double-bladed paddle. The cockpit is covered by a spraydeck (skirt) that keeps the inside of the boat (and the paddler's lower body) dry. The spraydeck or similar waterproof covering attaches securely to the edges of the cockpit, preventing the entry of water from waves or spray, and making it possible, in some boats, to roll the kayak, capsizing and righting the boat without it filling with water or ejecting the passenger. Some modern kayaks eliminate cockpits, seating the paddler(s) on top of the boat or replace paddles with other propulsion methods.
Man sitting with legs covered in boat that tapers to a point at each end holding long, pointed, wooden pole
Inuit seal hunter in a kayak, armed with a harpoon

The kayak was invented and first used by the native Ainu, Aleut and Eskimo hunters in sub-Arctic regions of northeastern Asia, North America and Greenland. In some parts of the world, such as the United Kingdom, kayaks are referred to as canoes and vice versa. Inuit/Eskimo Kayaks are a type of a generic class of boat of Canoe Shape. Continental European and British canoeing clubs and associations of the 19th Century used craft similar to kayaks, but referred to them as canoes. This explains the naming of the International and National Governing bodies of the sport of Canoeing.

Racing Kayaks



There are a lot of different kinds of racing kayaks, but almost all have the characteristic of being fast. There are several things that contribute to speed. You will often here about "hull speed" in relation to boat speed. This term is a misnomer in that it implies that there is a speed a hull will go. What it really indicates is the speed at which the hull starts to become rapidly more inefficient.

What hull speed suggests is that longer boats can go faster than shorter boats. This does not mean that they are automatically faster, just that a longer boat starts losing efficiency at a higher speed than a short boat.

The other big factor in speed is "wetted surface area" or how much surface area is in the water. This is important because as you move through the water the water must slide across the surface of the boat. The more surface there is to slide against, the more friction there will be and the slower the boat will go.

The easiest way to reduce the wetted surface area is to make the boat narrower. As a result, there are two primary options for making a racing boat fast: make it long and make it narrow. Therefore, most racing kayaks you see will be as long and narrow as they can get away with. There are typically constraints on these factors. For example, if you make a boat too narrow, it can be so unstable as to be impossible to keep upright. The other big constraint is racing rules.

Most race organizers will set maximum lengths and minimum widths in an effort keep to their events as fair as possible. Their goal is to make the race a test between individual paddlers, not a test of the fastest boat. However, it is the kayak designer's task to try to develop the fastest boat permitted within the rules.

This battle between race organizers and boat designers can create some funny looking boats, but the most common solution creates a boat with a plumb bow and stern. In this way, the boat can get as long a waterline as possible within the prescribed overall length. You will also often see a fair amount of "flare" in the cross sectional shape of the boat. This permits a narrow waterline beam with a wider overall beam that meets the rule specifications.

Neither of the these solution necessarily result in the best boat possible for the purpose if there were no design constraints imposed, but they can make the boat quite fast within those constraints.

The other consideration in a racing boat is stroke mechanics. Despite kayak designers best efforts to make a fast boat, in the end there are really only fast motors. In order to go fast, the person paddling a kayak needs to be strong and have good technique. The design of the boat will often include features that help the motor maintain a good and strong paddle stroke.

The boat should not get in the way of the stroke, and the cockpit should let the paddler move as needed to paddle with full power. This often means the boat is quite narrower in front of the cockpit for a clean start of the stroke. The cockpit may be long to permit the paddlers legs to move.

*Nur amik dr internat 'http://www.guillemot-kayaks.com/guillemot/information/kayak_design/varieties_of_kayaks/racing_kayaks'

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