Kayaks
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Wikipedia-Article "Kayaks"
For the Dutch rock band of the same name see Kayak (band)
A kayak is a type of small human-powered boat; a covered variant of a canoe, which is often called a canoe in Great Britain and Ireland, typically used with a double-bladed paddle instead of a canoe's single bladed paddle.
The user or paddler sits down in the kayak with feet facing forward. The top of the kayak is covered with a deck. The paddler sits in a hole in the cockpit which may be sealed off with a spray skirt (or spraydeck). This stops water splashing over the boat from entering it, and makes it possible that, should the kayak (capsize), the kayak will not fill with water, and the paddler, with skill, can right the kayak again without taking on water. This manoeuvre is known as an Eskimo Roll.
In modern times kayaks have been further developed into several types including: whitewater, playboats, surfing, sea kayaks, flat-water racing, downriver racing, slalom, canoe polo and recreational. These types may also be subdivided. Modern kayaks are made of plastic, fiberglass, kevlar, carbon fiber, canvas, other fabrics, or wood. They come in one, two, and occasionally three person models. Some sit-on-top boats are also called kayaks, as the paddler propels the boat with a double-ended paddle.
The design of different types of kayak is largely a matter of two types of trade-offs. The first trade-off important to all kayaks is between directional stability ("tracking") and maneuverability. As a general rule, a longer boat is faster while a shorter boat may be turned more quickly. A longer hull creates a smoother transition from the narrow bow to the widest part of the boat and so "cuts" through the water with less resistance much like a sharp knife cuts more easily than a dull one. Longer boats also have a higher maximum non-planing hull speed, but the effect is largely offset by increased friction, and only becomes a significant factor at racing speeds. Kayaks that are built to cover longer distances such as touring and sea kayaks are themselves longer, generally between 15 and 18 feet. Flat water racing kayaks, which are built for maximum speed and efficiency, may be over 20 feet in length. Whitewater kayaks, which generally depend upon river current for their forward motion, are built quite short, to maximize maneuverability. These kayaks rarely exceed eight feet in length, and some specialized boats such as playboats may be only six feet long. The design of recreational kayaks is an attempt to compromise between tracking and maneuverability, while keeping costs reasonable; their length generally ranges from nine to fourteen feet.
Although length is an important feature of directional stability, length alone is a poor basis for guessing at the maneuverability of a kayak. A second design element that should be considered is rocker, or the curvature of the kayak from bow to stern. A heavily "rockered" boat curves more than a boat with little or no rocker, meaning that the effective waterline of the rockered boat is less than for a kayak with no rocker. For example, imagine a hoop 30 inches in diameter. When set on its edge on a table, only a small portion of that hoop touches the table. Although kayak hulls are not so extremely curved as a hoop, it is analogous to what happens when a kayak with rocker is sitting in the water: although the overall length of the boat may be 18 feet, the length at waterline may only be 16 feet. Similarly, although a whitewater boat may only be a few feet shorter than many recreational kayaks, because the whitewater boat is heavily rockered its waterline is far shorter and its maneuverability far greater.
After directional stabilty, the next most important design difference among kayaks is the tradeoff between primary and secondary stability. Primary stability refers to the feeling of "tippiness" one has when seated in the kayak on flat water. Although every kayak will have some amount of side-to-side rocking, a wide kayak normally feels less likely to capsize than a narrow one, and a flat-bottomed boat will feel more stable than one with a rounded or V-shaped hull. However, if one plans to take his or her kayak into rough water, secondary stability may be more important. Secondary stability refers to the ease of righting a kayak once it has been put off balance. The same boats that have lower primary stability will generally be easier to right once they are tipped too far in one direction. Thus, sea kayaks, which are meant to be taken into open water and rough conditions, are generally narrower (22-25 inches) and less stable feeling than recreational kayaks, which are wider (26-30+ inches) and have a flatter hull shape. Until recently, whitewater kayaks had very rounded hulls. Radical changes in design philosophy, however, have lead to whitewater kayaks with very flat hulls that allow them to sit on top of the water (planing hull) rather than in the water (displacement hull) like most other boats.
There are, of course, many more elements of kayak design— see the external links for more information. Most kayaks are rigid hulled, although folding kayaks that can be transported easily, and inflatable kayaks are not uncommon.
A special type of kayak using pedals allows the kayaker to propel the vessel with underwater "flippers" .
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Origins
Kayaks were originally developed by the Inuit, the indigenous peoples living in the Arctic regions of North America and Greenland. The word "kayak" means "man's boat". These first kayaks were constructed as a wooden frame covered by an animal skin such as seal skin. Kayaks were originally built by the man who would use them (with substantial assistance from his wife, who would typically sew the skins). The skin jacket of the hunter is then sewn into the skins of the kayak, to create a waterproof seal. The man would measure the frame for the kayak based on his forearm, and a typical kayak is about 19ft long. This measurement style confounded early European explorers who tried to duplicate the kayak because each kayak was a little different. Kayaks were used to hunt on the coastal and open waters of the Arctic Ocean, usually with harpoons and lances, but also with bird hooks. Because the user was sewn into the boat, it was almost like a piece of clothing, 'worn' by the boater. This meant that what is now known as a 'wet exit' (getting out of a kayak that has overturned, righting it, and getting back in) was impossible, leading to the importance of the eskimo roll manoeuvre, where the kayak is righted without leaving the cockpit. For the Inuit, without modern floatation devices or cold water protection, being thrown into the freezing waters of the Arctic Ocean was almost certain death in any event. Greenland style boats are typically narrower, and are paddled with greenland paddles, typically wooden, long and narrow.
Skin on frame kayaks
Often an umbrella term for several types of kayaks, Skin on Frame boats are primarily considered a more traditional boat in design, materials, construction, and technique. They are often the lightest kayaks, and traditionally made of drift wood pegged and or lashed together and seal skin stretched over it, as those were the easiest materials to source in the arctic regions.
The Dutch were some of the first Europeans to take interest in the indigenous American boat design, spelling the name for these Inuit & Aleut boats, Qajaq. This spelling of the word kayak has evolved to be synonymous with “traditional kayak” and often encompasses three sub categories of boats separated by development local:
Baidarkas, from the Alaskan & Aleutian seas, and are a much older design. Their more rounded shape and high number of chines give them an almost Blimp-like appearance.
West Greenland kayaks are what most neo-traditional polymer boats are modeled after. Possessing often fewer chines they are more angular in shape, the gunnels rising to a point at the bow and stern.
East Greenland kayaks appear similar to the West Greenland boat, but are often more snugly fitted to the boater and possess a steeper angle between gunnel and stem. Lending maneuverability traits more adapted to the local environment.
Folding kayaks
A special type of skin-on-frame kayak is the folding kayak, the direct descendant of the original Inuit kayak. A folder is a modern kayak that uses a collapsible frame, of wood, aluminum or plastic, or a combination thereof, and a skin, of some sort of water-resistant and tough fabric. Many types have integral air sponsons inside the hull, making the kayaks virtually unsinkable.
Folders are known for their durability, stability, and longevity: The Klepper Aerius I, a single-seater, has been used successfully for white-water kayaking, due to its durability and excellent manouvrability, while many Kleppers have been in frequent use for more than 20 years.
Folding kayaks exhibit many of the same paddling characteristics as the original skin-and-frame vessels of the circumpolar north. Of all modern kayaks, they are closest relatives to the skin-and-frame boats of the past.
Whitewater kayaks
Whitewater kayaks are generally made out of high impact plastic, usually polyethylene. They are shorter than other types of kayaks. The size usually ranges from 6 to 10 feet/2 to 3 metres long; the trend was toward the shorter boats, but this is now reversing slightly to longer boats of around 7 to 8 feet that can become airborne more easily. Whitewater kayaks are among the most maneuverable types made, however they are much slower than many other styles of boat. Whitewater boats, however, do not need inherent speed. Their speed comes from their ability to ride the crest of flowing river. In "freestyle" competition ("kayak rodeo"), whitewater kayakers use features of rapids to do tricks, typically while remaining in one place on the river.
Ultra-low-volume kayaks that are designed to be paddled both on and below the surface of the water are used in Squirt Boating.
Surf kayaks
Surf Kayaks are similar in design to whitewater kayaks, except they have a planing hull (flat side to side) to carve into a wave face, like a surfboard. While typically seven or eight feet in length, competition surf kayaks can be nearly twelve feet long to increase both planing speed while on a wave and to provide faster paddling speed for catching waves.
A variation on the closed cockpit surf kayak is an open cockpit design called a Waveski. Although the waveski utilises similar dynamics, in terms of paddling technique and surfing performance on the waves, construction can be very similar to surfboard designs. Elite waveski surfers are able to more closely imitate surfboard manouveres.
Recreational kayaks
Recreational kayaks are designed for the casual paddler interested in fishing, photography, or a peaceful paddle on a lake or flatwater stream; they presently make up the largest segment of kayak sales. Compared to other kayaks recreational kayaks have a larger cockpit for easier entry and exit and a wider beam (27–30 inches) for more stability on the water; they are generally less than twelve feet in length and have limited cargo capacity. Using less expensive materials like polyethylene and including fewer options keep these boats inexpensive ($300–$800). Most canoe/kayak clubs will offer indroductory instruction programs in recreational boats as a way to enter into the sport.[1]
Flatwater racing kayaks
Flatwater racing kayaks are generally made out of lightweight materials, and as such, are somewhat weak; they are not intended for anything other than flat water on a relatively calm day. They are thin, extremely unstable, and expensive, with a competitive boat running in the $4000 range. They require a good level of expertise to paddle well, but are extremely fast in the hands of proficient users. The beam of a flatwater boat is typically barely wider than the hips of the person who paddles it, allowing for a very long and narrow shape to reduce drag. The most common types of flatwater racing kayaks (sometimes termed 'sprint boats') are K-1, K-2 and K-4. These boats are raced at the Olympic level by both men and women, over courses of 200m, 500m and 1000m.
Due to their long length (a one person sprint kayak will be on the order of 17 feet long), sprint boats come equipped with a rudder to help with turning. The rudder is controlled by the feet of the paddler (the foremost paddler in multiperson designs). In spite of this, these boats still require fairly large areas to turn.
Flatwater racing kayaks are closely related to flatwater racing canoes, and are usually paddled out of a common club or team, although it is rare for paddlers to compete in both canoes and kayaks.
A highly specialized variant of flatwater racing kayak called a Surf Ski has an open cockpit and can be twenty-one feet long but only eighteen inches wide, requiring expert balance and paddling skill. Surf Skis were originally created for surf and are still used in surf races in countries such as New Zealand, Australia, South Africa.
Inflatable kayaks
Another special type of kayak is the inflatable kayak. Inflatable kayaks usually can be transported by hand using a carry bag. They can be inflated with foot pumps, a variety of hand pumps, or electric pumps. The pressure sounds low, almost always below 3 psi.
They are made of hypalon (a kind of neoprene), pvc, or polyurethane coated cloth.
Besides being portable, inflatable kayaks generally are stable and easy to master, but they take more effort to paddle and are slower than traditional kayaks.
See also
External links
- Boater Talk An international whitewater paddling forum.
- Kayak design
- KayakDude.com Kayaking portal with news, articles and links to kayak related sites.
- Kayakwiki, A wiki site devoted exclusively to kayaks and kayaking
- The Kayaking Journal
- KayakInstruction.org, A non-profit organization providing whitewater kayak training
- http://www.mountainbuzz.com A site for Colorado kayakers
- NSW Sea Kayak Club (New South Wales, Australia) - a top-resource on all things sea kayaking: From skills and technique to nutrition facts, from preparation for expedition kayaking to trip suggestions.
- paddlepedia - Another newer wiki about paddling
- Paddling.net A site dedicated to all paddle related sports including kayaking.
- purepaddling.com - An online community of surf ski paddlers, sea kayakers and other paddlers
- Qajaq USA, A non-profit comitted to promoting Greenland style kayaking
- ThamesWeirProject Community and information for Thames Paddlers in the UK
- WaterTribe A non-commercial site devoted to small, human powered boats and expedition racing