Kayak

Some kayaks are also fitted with external sources of propulsion, such as a battery-powered electric motor to drive a propeller or flippers, a sail (which essentially modifies it into a sailboat), or even a completely independent gasoline outboard engine (which converts it into a de facto motorboat).

This enabled the "eskimo roll" and rescue to become the preferred methods of recovery after capsizing, especially as few Inuit could swim; their waters are too cold for a swimmer to survive for long.

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

Contemporary traditional-style kayaks trace their origins primarily to the native boats of Alaska, northern Canada, and Southwest Greenland.

This type of kayak was introduced to England and Europe by John MacGregor (sportsman) in 1860, but Klepper was the first person to mass-produce these boats made of collapsible wooden frames covered by waterproof rubberized canvas.

In June 1928, a German named Franz Romer Sea kayak rigged his 6.1 m (20 ft) long foldboat with a sail and departed from Las Palmas in the Canary Islands carrying 270 kg (590 lb) of tinned food and 210 L (55 U.S. gal) of water.

Another German, Oskar Speck, paddled his foldboat down the Danube and four years later reached the Australian coast after having traveled roughly 14,000 miles across the Pacific.

If the displacement is excessive, the kayak will float too high, catch the wind and waves uncomfortably, and handle poorly;[21] it will probably also be bigger and heavier than it needs to be.

Primary (sometimes called initial) stability describes how much a boat tips, or rocks back and forth when displaced from level by paddler weight shifts.

Secondary stability describes how stable a kayak feels when put on edge or when waves are passing under the hull perpendicular to the length of the boat.

Many paddlers also customize their kayaks by putting in shims of closed-cell foam[34] (usually EVA[35]), or more elaborate structures, to make it fit more tightly.

New drop-stitch technology means slab, rather than tube shapes are used in the designs with higher inflation pressures (up to 0.7 bar (10 psi)), leading to considerably faster, though often less stable kayaks which rival hardshell boats in performance.

This is a good choice for the first-time kayak builder as the labor and skills required (especially for kit versions) is considerably less than for strip-built boats which can take three times as long to build.

An experienced woodworker can build one for about US$400 in 200 hours, though the exact cost and time depend on the builder's skill, the materials and the size and design.

Today, seal skin is usually replaced with canvas or nylon cloth covered with paint, polyurethane, or a hypalon rubber coating, on a wooden or aluminum frame.

Engineer Xyla Foxlin built a kayak out of transparent fibreglass as well as LEDs to create a floating vessel that lights up at night, which she calls the Rainbowt.

Modern kayaks serve diverse purposes, ranging from slow and easy touring on placid water, to racing and complex maneuvering in fast-moving whitewater, to fishing and long-distance ocean excursions.

Modern forms, materials and construction techniques make it possible to effectively serve these needs while continuing to leverage the insights of the original Arctic inventors.

Recreational kayaks are designed for the casual paddler interested in fishing, photography, or a peaceful paddle on a lake, flatwater stream or protected salt water away from strong ocean waves.

Sea kayaks are typically designed for travel by one, two or even three paddlers on open water and in many cases trade maneuverability for seaworthiness, stability, and cargo capacity.

Increasingly, manufacturers build leisure 'sit-on-top' variants of extreme sports craft, typically using polyethylene to ensure strength and affordability, often with a skeg for directional stability.

Sit-on-top kayaks are particularly popular for fishing and SCUBA diving, since participants need to easily enter and exit the water, change seating positions, and access hatches and storage wells.

In playboating or freestyle competition (also known as rodeo boating), kayakers exploit the complex currents of rapids to execute a series of tricks, which are scored for skill and style.

A specialized variant of racing craft called a surf ski has an open cockpit and can be up to 6.4 m (21 ft) long but only 46 cm (18 in) wide, requiring expert balance and paddling skill.

Recently some manufacturers have added an internal frame (folding-style) to a multi-section inflatable sit-on-top kayak to produce a seaworthy boat.

The appeal of inflatable kayaks is their portability, their durability (they don't dent), ruggedness in white water (they bounce off rocks rather than break) and their easy storage.

Modern folding kayaks are constructed from a wooden or aluminum frame over which is placed a synthetic skin made of polyester, cotton canvas, polyurethane, or Hypalon.

This mechanism usually consists of pedals that are rotated in a circular motion, akin to bicycling, generating forward momentum through a propeller or fins situated beneath the kayak.

[39] Traditional multi-hull vessels such as catamarans and outrigger canoes benefit from increased lateral stability without sacrificing speed, and these advantages have been successfully applied in twin hull kayaks.

[44] The Australian Military MKII and MKIII folding kayaks were extensively used during WWII in the Pacific Theater for some 33 raids and missions on and around the South-East Asian islands.