kayak

A kayak is a small human-powered boat. It typically has a covered deck, and a cockpit covered by a spray skirt. It is propelled by a double-bladed paddle. The kayak was originally developed by native Aleut and Inuit hunters in sub-arctic regions of North America and Greenland. Modern kayaks come in a wide variety of designs and materials for specialized purposes.

Kayaks typically accommodate one, two or occasionally three paddlers who sit facing forward in one or more cockpits below the deck of the boat. The spray skirt or similar waterproof garment attaches securely to the edges of the cockpit, preventing the entry of water from waves or spray, and making it possible in most styles of boat, to roll the kayak upright again without it filling with water or ejecting the paddler.

Kayaks differ distinctly in design and history from canoes, which are more flat-bottomed boats propelled by single-bladed paddles, although some modern canoes may be difficult for a non-expert to distinguish from a kayak. Kayaks are often called canoes in several countries like Great Britain and Ireland.

Origins

Kayaks (Inuktitut: qajaq, Inuktitut syllabics: ᖃᔭᖅ) were originally developed by the Aleuts and Inuit indigenous peoples living in the Arctic regions of North America and Greenland, who used the boats to hunt on inland lakes, rivers and the coastal waters of the Arctic Ocean and the North Atlantic and North Pacific oceans. These first kayaks were constructed from stitched animal skins such as seal stretched over a wooden frame made from collected driftwood, as many of the areas of their construction were treeless. Archaeologists have found evidence indicating that kayaks are at least 4000 years old.

Though the term "kayak" is now used broadly for this class of boat, native people made many different types of boat for different purposes. The baidarka is double or triple kayak developed by indigenous cultures in Alaska and was used for hunting and transporting passengers or goods. An umiak ("women's boat") is a larger open decked boat ranging from 17 feet to 60 feet, made with seal skins and wood. It was paddled with single bladed paddles and typically had more than one paddler. It is thought the kayak originally started out as a decked over umiak and evolved into its traditional form.

The word "kayak" means "man's boat" or "hunter's boat", and native kayaks were a very personal craft, built by the man who would use them (with assistance from his wife, who would sew the skins) fitting his measures, for maximum maneuverability. The skin jacket of the hunter was then sewn into the skins of the kayak, to create a waterproof seal.

The builder used found materials and anthropomorphic measurements, using his own body, to create a kayak conforming closely to his own body. For example - typically the length was 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 long by 20-22 inches wide by 7 inches deep. This measurement style confounded early European explorers who tried to duplicate the kayak because each kayak was a little different.

Because the user was sewn in, the boat 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 maneuver, where the kayak is righted without leaving the cockpit.

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) were dominating the market up until 1950s, when fiberglass boats were first introduced. Rotomolded plastic kayaks first appeared in 1973.

Modern kayaks

Modern kayaks have evolved into numerous specialized types, that may be broadly categorized as sea kayaks, whitewater (or river) kayaks, surf kayaks, and racing kayaks, though many hybrid types exist as well. Sea kayaks are typically designed for travel by one or two paddlers on open water and trade manueverability for seaworthiness, stability, and cargo capacity. Sea-kayak sub-types include open-deck "sit-on-top" kayaks, recreational kayaks, and collapsible "skin-on-frame" boats. Whitewater kayaks are highly maneuverable boats, usually for a single paddler, and include such specialized boats as playboats and slalom kayaks. Surf kayaks, often called "surf skis", are specialized narrow and long boats for surfing breaking waves and surf-zone rescues. Racing kayaks are designed for speed, and usually require substantial skill to achieve stability, due to extremely narrow hulls, though downriver racing kayaks are a hybrid style with whitewater boats.

Modern kayaks are typically constructed from rotomolded plastic, wood, fabrics over wooden or aluminum frames, fiberglass, Kevlar, or carbon fiber. They come in one, two, and occasionally three or four person models.

Sea Kayaks

The sea kayak, though descended directly from traditional designs and types, is implemented in a wide variety of materials, and with many distinct design choices. Sea kayaks as a class are distinct from whitewater kayaks and other boats by typically having a longer waterline (emphasizing straight travel through the water over extreme maneuverability), and provisions for below-deck storage of cargo. Sea kayaks may also have rudders or skegs (also for enhanced straight-line tracking), and such features as upturned bow or stern profiles for wave shedding. Modern sea kayaks often have two or more internal bulkheads to provide watertight internal sections for flotation and waterproof storage. Sea kayaks, unlike most whitewater kayaks, may be built to accommodate two or sometimes three paddlers.

Strip Built Kayaks

Strip built kayaks are similar in shape to commercially available rigid fiberglass kayaks but much lighter. These hand built kayaks are both a work of art and a light weight craft. However they are much more fragile, and subject to wear, rendering them impractical for normal use. Like their fiberglass counterparts the shape and size of the strip built kayaks determine how they perform and what uses are optimal. The kayaks are built with thin strips of lightweight wood, often Cedar, Pine or Redwood. The strips are glued together around a form, stapled or clamped in place, and allowed to dry. The boats strength comes from a layer of fiberglass cloth and resin, inside and out. Strip built kayaks are sold by a few companies, prices start from around $4,000 and up. Anyone who is an avid woodworker could build one for about $400 in 200 hours. The exact cost and time will be determined by the builder's skill, materials chosen and design of the kayak.

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 were traditionally made of driftwood pegged or lashed together and stretched seal skin, as those were the most readily available materials in the arctic regions. Today, the seal skin is usually replaced with canvas or nylon cloth covered with paint, neoprene, or a hypalon rubber coating.

The word kayak has evolved to be synonymous with “traditional kayak” and often encompasses three subcategories of boats: 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 are often more snugly fitted to the paddler and possess a steeper angle between gunwale and stem which lend maneuverability.

Most of the Inuit peoples from the Aleutian Island eastward to Greenland relied on the kayak for hunting a variety of prey — primarily seals, though whales and caribou were important in some areas. 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.

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.

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 with a collapsible frame, of wood, aluminum or plastic, or a combination thereof, and a skin, of some sort of water-resistant and durable fabric. Many types have integral air sponsons inside the hull, increased secondary stability and 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 maneuverability, 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.

Sit-on-tops

Sealed-hull (unsinkable) craft were developed in the past for low level leisure use, as derivatives from surfboards (e.g. paddle or wave skis), or for surf conditions. Variants include planing surf craft, touring kayaks, and sea marathon kayaks. Increasingly, manufacturers are building leisure 'sit-on-top' variants of extreme sports craft, often with a skeg (fixed rudder) for directional stability. Water that enters the cockpit drains out through scupper holes - tubes that run from the cockpit to the bottom of the hull. Sit-on-top kayaks usually come in single and double (two paddler) designs, although a few models accommodate three or four paddlers. Sit-on-top kayaks are particularly popular for fishing and diving, since participants need to easily enter and exit the water, change seating positions, and access hatches and storage wells. Ordinarily the seat of a sit-on-top is slightly above water level, so the center of gravity for the paddler is higher than in a traditional kayak. To compensate for the center of gravity, a sit-on-top is often wider than a traditional kayak of the same length, and is considered slower as a result.

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 (US$300–$800). Most canoe/kayak clubs offer introductory instruction in recreational boats as a way to enter into the sport. [1]

Fishing kayaks

The native people of the Arctic regions did not rely much on kayaks for fishing. However, in recent years sport fishing from kayaks has become popular in both fresh and salt water, especially in warmer regions. Fishing kayaks are similar in design to recreational sit-in and sit-on-top kayaks, but since fishing requires a higher degree of lateral stability mono-hull fishing kayaks are usually very wide (up to 36 inches beam) and often equipped with outriggers. Catamaran or twin hull fishing kayaks (rigid and inflatable) are growing in popularity because of their increased lateral stability, with some models enabling the user to cast standing and even to paddle standing while looking for fish. Fishing kayaks are often equippped with integrated rod holders, GPS, electronic fish finders, trolling motors, fish tanks and other accessories.

Whitewater kayaks

Whitewater kayaks are generally made out of rigid, high impact plastic; usually polyethylene. They are shorter than other types of kayaks, ranging from 5.5 to 10 feet (2 to 3 metres) long. Modern design has moved toward shorter boats, which make them very maneuverable but slow. However, whitewater boats do not need inherent speed, because they move downriver with current. 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 Kayaking uses kayaks that 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 maneuvers.

Racing kayaks

Flatwater racing kayaks

Flatwater racing kayaks are generally made out of very lightweight materials. 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 K-1 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 (single paddler), K-2 (two paddlers) and K-4 (four paddlers). These boats are raced at the Olympic level by both men over courses of 500 m and 1000 m and women, over courses 500 m only.

Due to their length (a one person sprint kayak is 17 ft (5.2 m) 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 make fairly large turns.

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 New Zealand, Australia, and South Africa. They have become very popular in the United States for both ocean races, lake races and even downriver races.

Slalom kayak

Kayaks designed for Slalom canoeing have a hull for maneuverability and—since the early 1970s—low profile decks.

Specialty and multi-type kayaks

Inflatable kayaks

Another special type of kayak is the inflatable kayak. Inflatable kayaks usually can be transported by hand using a carry bag. They are made of hypalon (a kind of neoprene), pvc, or polyurethane coated cloth. They can be inflated with foot, hand or electric pumps. Multiple compartments in all but the least expensive increase safety. They generally use low pressure air, almost always below 3 psi.

Until recently, inflatable kayaks have been non-rigid boats, essentially pointed rafts, and best suited for use on rivers and calm water. However, recently some manufacturers have combined folding kayak design principles (notably the use of an internal frame) with Sit-on-top kayak overall design using multiple inflatable sections to produce a seaworthy inflatable sea kayak.

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.

Pedal kayaks

A special type of kayak using pedals allows the kayaker to propel the vessel with a propeller or underwater "flippers" attached to pedals in the cockpit, rather than a with a paddle. This allows the kayaker to keep his or her hands free for fishing or other activities, but introduces a somewhat delicate mechanical component into the boat and eliminates the paddle as a tool for capsize-prevention and self-rescue.

Multi-hull kayaks

These kayaks have more than one hull, which generally increases their lateral stability and improves tracking. Multi-hull kayaks are used in applications such as touring, sea kayaking, racing, whitewater, recreation, fishing and sailing. Multi hull kayaks are made using all materials and building techniques that are commonly used in manufacturing mono (single) hull kayaks, including rotationally molded polyethylene, fiber reinforced plastics (FRP) also known as 'composites' and wood, and some of them are inflatable. Multi hull kayaks can be devided into two main categories:

Outrigger kayaks

The older type of multi hull kayaks. Such kayaks are characrized by having a traditional main hull - either a sit-in or sit-on-top kayak equipped with either a single, smaller hull or a pair or such hulls (outriggers) attached to it.

Twin hull kayaks

This kayak design is characterized by its two identical hulls, or by one hull split in two along its longitudinal axis - depending on the intended use. Most twin hull kayaks are largely inspired by the catamaran concept and are operated from the top of a platform bridging the two hulls, and by that resemble mono hull sit-on-top kayaks. However, the newest twin hull kayaks are operated from inside the cockpit, with the paddler's legs stretching down to the bottom of each hull. By that they are comparable to sit-in kayaks, although they offer additional paddling positions. Such kayaks are also used for surfing and for kayaking in the standing position (wave walking, kayak-skiing).

Modern kayak design

The design of different types of kayak is largely a matter of three dimensions of trade-off: between directional stability ("tracking") and maneuverability, the second between primary and secondary stability. The third is between overall speed and overall lateral stability. The first and third tradeoffs can be largely avoided in twin hull kayak designs.

Length: As a general rule, a longer kayak is faster while a shorter kayak may be turned more quickly - but the higher potential top speed of the longer kayak is largely offset by increased friction. Kayaks that are built to cover longer distances such as touring and sea kayaks are themselves longer, generally between 16 and 19 feet. A flat water racing K1's maximum length governed by the ICF is 17 feet. 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.

Rocker: Length alone does not fully predict the maneuverability of a kayak: a second design element is rocker: the curvature of the kayak from bow to stern. A heavily "rockered" boat has more lengthwise curvature 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, an 18 ft. kayak with no rocker will be entirely in the water from end to end. In contrast, the bow and stern of an 18 footer with will be out of the water, so its lengthwise waterline may be only 16 ft. Rocker is generally most evident at the ends, and in moderation improves handling. 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.

Hull form: Kayak hull designs are divided into categories based on the shape from bow to stern and on the shape of the hull in cross-section. Bow-to-stern shapes include:

• Symmetrical: the widest part of the boat is halfway between bow and stern.
• Fish form: the widest part is forward of the midpoint.
• Swede form: the widest part is aft (in back) of the midpoint.

The presence or absence of a V bottom at various points affects the kayak's tracking and maneuverability. A V tends to improve the kayak's ability to travel straight (track), but reduces the ease of turning. Most modern kayaks have steep Vee sections at the bow and stern, and a very shallow Vee amidships.

Beam profile: Hull shapes are categorized by the roundness (or flatness) of the bottom, whether the bottom comes to a "V" at various points on the hull, and by the presence, absence, and severity of a chine, where the side and bottom of a hull meet at an angle, creating another edge below the gunwales. This design choice determines the tradeoff between primary and secondary stability. The hull design determines the relative primary stability and secondary stability of a kayak, the resistance of the boat to tipping and to ultimate capsize, respectively.

Primary and secondary stability: Although every kayak will rock from side-to-side, wider kayaks with more buoyancy away from the centerline will present more resistance to tipping and thus feel less likely to capsize than a narrow one with less buoyancy away from the centerline. Flat-bottomed boats that push their volume away from the centerline will also feel more stable than rounded or V-shaped hull shapes that distribute buoyancy more evenly.

While flat-bottomed boats have more primary (sometimes called "initial") stability, and feel more stable to the beginner they usually have less secondary stability. Once they do begin to tip, they capsize quickly and suddenly. Rounder-bottomed boats are quite the opposite — having lower initial or primary stability and (usually) greater secondary stability. The chine in some boats increases secondary stability by effectively widening the beam of the boat when it is heeled (tipped).

Secondary stability refers to final stability, or additional resistance to capsizing as a kayak approaches capsizing. Rounder-bottomed boats present a greater cross-section to the water as they are tipped from level ("heeled"), while very flat-bottomed boats present less. Sea kayaks, designed for open water and rough conditions, are generally narrower (22-25 inches) and have more secondary stability than recreational kayaks, which are wider (26-30+ inches), have a flatter hull shape, and more primary stability. Kayaks with only moderate primary, but excellent secondary are, in general, considered more seaworthy, especially in challenging conditions.

Until recently, whitewater kayaks had very rounded and rockered hulls, but changes in design philosophy have lead to whitewater kayaks with very flat planing hulls that allow them to sit on top of the water rather than in the water (displacement hull).

Trivia

The word "kayak" is a palindrome — a word spelled the same forward and backward.

See also

• Whitewater kayaking
• Sea kayaking
• Canoe
• Royak
• Flyak
• Canyoning
• Playboating
• Squirt Boating
• Recreational kayak
• Surf Kayaking
• List of kayak clubs.

References

• Kayak at the Asuilaak Living Dictionary

External links

• USA Canoe and Kayak The National Governing Body of Kayaking in the USA
• Kayak design An series of articles about kayak and paddle design.
• The Kayaking Journal
• Qajaq USA, A non-profit committed to promoting Greenland style kayaking
• British Canoe Union The National Governing Body of Kayaking in the UK
• Wikipaddle - kayak and canoe wiki - focus is on places to paddle.
• KayakWiki - A wiki focused primarily on kayak techniques and construction
• International Human Powered Vehicle Association website - information on peddle kayaks
• Kayak Design - Comparison Technical article comparing hydrodynamics and hydrostatics of traditional (mono hull) and new twin hull kayak designs. Includes a list of references.