A
kayak is a small human-powered
boat. It typically has a covered deck, and a cockpit
covered by a
spraydeck also known as a
skirt.
The
kayak was used by the native Ainu,
Aleut and Eskimo
hunters in sub-Arctic regions of northeastern Asia, North America and
Greenland
. It historically was, and often still is,
propelled by a double-bladed
paddle in the
hands of a sitting paddler. Modern kayaks come in a wide variety of
designs and materials for specialized purposes.
In some parts of the
world, such as the United
Kingdom
, kayaks are referred to as canoes and vice versa.
Sport kayaker at Great Falls,
Virginia
Design
Traditional kayaks typically accommodate one, two or occasionally
three
paddlers who sit facing forward in one
or more cockpits below the deck of the boat. If used, the
spraydeck 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 some styles of
boat, to
roll the kayak upright again
without it filling with water or ejecting the passenger.
Inuit/
Eskimo Kayaks are
a type of a generic class of boat of Canoe Shape. European Canoeing
clubs and associations of the 19th Century used similar craft to
what are now called Kayaks, but referred to these as types of
Canoe. This explains the naming of the International and National
Governing bodies of the sport of Canoeing.
John MacGregor
Origins
Kayaks
(Inuktitut: qajaq, Inuktitut syllabics: ᖃᔭᖅ) were
originally developed by indigenous people living in the Arctic regions, who used the boats to hunt on inland
lakes, rivers and the 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 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.
The oldest still existing kayaks are
exhibited in the North America department of the State Museum of
Ethnology
in Munich
.
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 developed by
indigenous cultures in Alaska was also made in double or triple
cockpit designs, and was used for hunting and transporting
passengers or goods. An
umiak is a large open
sea canoe, ranging from to , 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 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. A special skin jacket,
Tuilik, was then laced to the kayak, creating
a waterproof seal. This made the
eskimo
roll the preferred method of regaining posture after turning
upside down (from the kayaking point of view, it's not a capsize
until you come out of the boat), especially as few Eskimos could
swim; their waters are too cold for a swimmer to survive for very
long.
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 from the boat.
The builder used found materials and anthropomorphic measurements,
using his own body, to create a kayak conforming closely 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 long by 20-22 inches wide by deep.
This measurement style 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 are often more snugly fitted to the
paddler and possess a steeper angle between gunwale and stem which lend
maneuverability.
Most of the Eskimo 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.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.
This Greenland paddle is in length,
and much narrower than European paddles.
Modern kayaks
Modern kayaks have evolved into numerous specialized types, that
may be broadly categorized according to their application as
sea kayaks,
whitewater (or
river)
kayaks,
surf kayaks, and
racing kayaks
(flat water, white water, or slalom), though many hybrid types
exist as well, broadly labeled
recreational kayaks. The
label "kayak" is often misapplied to other small, human-powered
vessels not descended from the kayak tradition, including
multi-hull or outrigger boats and those which elevate above the
water on hydrofoils.
Sea kayaks are typically
designed for travel by one or two paddlers on open water and in
many cases trade maneuverability 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 in some cases highly maneuverable boats, usually for a
single paddler, and include such specialized boats as
playboats and
slalom kayaks. White water racers combine a
fast, unstable lower hull portion with a flared upper hull portion
to combine flat water racing speed with extra stability in open
water: they are not fitted with rudders and have similar
manoeuvrability to flat water racers.
Surf skis, are
specialized narrow and long boats for racing, 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.
Surf Kayaks are in many
respects similar to whitewater boats, however often equipped with
up to three fins. Specialty surf boats typically have flat bottoms,
and hard edges, similar to surf boards. The design of a surf kayak
promotes the use of an ocean surf wave (moving wave) as opposed to
a river or feature wave (moving water). They are typically made
from
rotomolded plastic, or
fiberglass.
Modern kayaks are typically constructed from
rotomolded plastic, wood, fabrics over wooden or aluminum
frames,
fiberglass,
Kevlar, or
carbon fiber.
Most kayaks accommodate one or two paddlers, but some
special-purpose boats may accommodate more.
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. Certain sea kayaks can even be used for
surfing.
Wooden kayaks
Kayaks made from thin wood sheathed in fiberglass have proven
successful, especially as the price of
epoxy
resin has decreased in recent years. Two main types are
popular, especially for the homebuilder:
Stitch & Glue, and
Strip-Built.
Stitch & Glue designs use modern, marine-grade
plywood—typically quarter-inch (5mm) thick. After cutting out the
required pieces of hull and deck (kits will often have these
pre-cut), a series of small holes are drilled along the edges.
Copper wire is then used to "stitch" the pieces together through
the holes. After the pieces are temporarily stitched together, they
are glued with epoxy and the seams reinforced with fiberglass. When
the epoxy dries, the copper stitches are typically removed. The
entire boat is then covered in fiberglass for additional strength
and waterproofing. This construction method is fairly
straightforward, but as the plywood does not bend to form curves,
design choices are limited. 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.
Strip-built kayaks are similar in shape to commercially available
rigid fiberglass kayaks but are generally both lighter and tougher.
Like their fiberglass counterparts the shape and size of the boat
determines how they perform and what uses are optimal. The hull and
deck are built with thin strips of lightweight wood, often Cedar,
Pine or Redwood. The strips are edge-glued together around a form,
stapled or clamped in place, and allowed to dry. This forms a
wooden shell, which is not inherently strong. The boat's strength
comes from a layer of fiberglass cloth and epoxy resin, inside and
out. Strip built kayaks are sold commercially by a few companies,
priced $4,000 and up. An experienced woodworker can build one for
about US$400 in 200 hours, though the exact cost and time will be
determined by the builder's skill, the materials chosen and the
kayak's size/design. As a second kayak project, or for the serious
builder with some woodworking expertise, a strip-built boat can be
an impressive piece of work. Kits with pre-cut and milled wood
strips are commercially available.
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 and the wood with
aluminum.
Folding kayaks
A special type of skin-on-frame kayak is the
folding kayak, the direct descendant of the
original Eskimo 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, increasing 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.
Military kayaks
Kayaks were adapted for military use in the
Second World War.
Used mainly by
British Commando and Special Forces, principally the Combined Operations Pilotage Parties
(COPPs), the Special
Boat Service
(at that time an Army unit) and the Royal Marines Boom Patrol
Detachment.
The latter
made perhaps the best known use of them in the Operation Frankton raid on Bordeaux
harbor.
Following the war the SBS was reformed as a Royal Marines unit and
the Klepper Aerius II
folding kayak
became a staple of its training and operations.
Sit-on-tops
Sealed-hull (unsinkable) craft were developed in the past for
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 these are normally built using polyethylene to ensure
strength and keep the price down, 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 SCUBA 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 (27–36 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–$580). Most canoe/kayak clubs offer
introductory instruction in recreational boats as a way to enter
into the sport. Sometimes advanced paddlers still use recreational
kayaks. They can fit all levels, but sometimes do not perform as
well in the sea. The recreational kayak is usually a type of
touring kayak.
[2463]
Whitewater kayaks
Whitewater kayak
Plastic
whitewater kayaks are
rotomoulded in a semi-rigid, high impact plastic, which is usually
polyethylene. Careful construction is
needed to ensure that the completed boat will remain structurally
sound when subjected to the forces of fast-moving water. A plastic
hull allows these kayaks to bounce off rocks without suffering
leaks, although they can be scratched and eventually worn through
with enough use. Standard whitewater boats are shorter than other
types of kayaks, ranging from 4 to 10 feet (1.25 to 3 metres) long.
There are two main types of whitewater kayak, and most experienced
paddlers own one of each.
One type, known as the playboat, is short, with a scooped bow and
blunt stern. These trade speed and stability for a high
maneuvrability. Their primary use is performing tricks in single
water features or short stretches of river. In playboating or
"freestyle" competition (also known in some parts of the US as
"rodeo" boating), kayakers exploit the complex currents of
rapids to do a series of tricks, which are scored for
skill and style.
The other primary type is the creekboat, which gets its name from
its purpose: running narrow, low-volume waterways. Creekboats are
longer and have far more volume than playboats, which makes them
faster and higher-floating. They are also designed to be very
stable. Many paddlers use creekboats in "short boat" downriver
races, and they are often seen on large rivers where their extra
stability and speed may be necessary to get through the
rapids.
Between the creekboat and playboat extremes is a general category
called "river running" kayaks. These medium-sized boats are
designed for rivers of moderate to high volume, and some, known as
"river running playboats", are capable of basic playboating moves.
They are typically owned by paddlers who do not have enough
involvement in whitewater to merit the purchase of multiple more
specialized boats.
Squirt Boating involves paddling both
on the surface of the river and underwater. Squirt boats must be
custom-fitted to the paddler in order to ensure comfort while
maintaining the low interior volume necessary to allow the paddler
to submerge him- or herself completely in the river.
Racing whitewater kayaks, like all racing kayaks, are made to
regulation lengths and are generally made out of fibre reinforced
resin (fiberglass) for speed. This makes them stiffer, lighter, and
less readily scratched than plastic hulls, though they are more
prone to breakage from impact. Repairs are often necessary,
especially if the paddler is inexperienced. Slalom kayaks are flat
hulled, highly manoeuvrable, and stable but not very fast in a
straight line; downriver white water racers have a combination hull
with a fast but unstable lower section similar to a flat water
racer's hull flaring out into a wider section higher up similar to
a slalom hull to provide stability in big water.
Polyethylene has replaced
fiberglass as a
construction material for most types of kayaks. However, squirt
boat and racing kayaks still perform better in the fiberglass
versions.
Surf kayaks
Traditional
Surf Kayaking comes in two
main varieties, High Performance (HP) Surf Kayaks and International
Class (IC) Surf Kayaks. HP boats tend to have a lot of nose
rocker, very little to no tail rocker,
very flat hulls, very sharp rails and up to four fins often
arranged in either a three fin thruster set up or a quad fin set
up. This enables them to generate lots of speed and be able to pull
very dynamic moves. IC boats have to be at least three meters long
and until a recent rule change had to have a convex hull; now a
flat hull and small concaves are also allowed, although fins are
still not allowed on IC boats. The surfing of international boats
tends to be smoother and more flowing. International class is often
thought of as the long boarding of the kayaking world. Surf boats
come in a variety of constructions ranging from tough but heavy
plastics to super light, super stiff but rather fragile foam cored
Kevlar carbon.
Surf Kayaking has become popular in
locations were you will find traditional surfboard surfing, as well
as new locations such as the Great Lakes
.
Surf Kayaking, utilizing boats similar to construction as many
whitewater varieties, is popular in many coastal areas. Specialty
Surf Kayaks, or whitewater kayaks fitted with fins, carry many
design similarities with surf boards.
See, Surf Kayaking
Waveskis
A variation on the closed cockpit surf kayak is sit-on-top 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 in speed and aerial performance.
Racing kayaks
Canoe sprint kayaks
The three types of Canoe sprint 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 men and women over courses of
200 m, 500m, and 1000m (women compete on 1000 m since 1997).World
Championship events:
- distances: 200 m, 500 m, 1000 m
- boat units: men and women K-1, K-2, K-4; men canoe C-1, C-2,
C-4 (women's C-1 and C-2 was exhibition at the 2009 world sprint
championships). All units compete on all distances. Each
country can send one unit per event (Mandatory since the 1966
championships).
Olympic events (effective for
2012
Summer Olympics):
- distances: 200 m, 500 m, 1000 m
- events: men K-2 200 m, K-1/K-2/K-4 1000 m; women K-1 200 m,
K-1/K-2/K-4 500 m, men canoe C-1/C-2 200 m, C-1/C-2 1000 m Each
country can send one unit per event.
Flatwater
racing kayaks are generally
made out of extremely lightweight composites such as
Kevlar,
carbon fiber, or
fiberglass. They are not intended for any
condition other than flat water. They are narrow, extremely
unstable, and expensive, with a competitive K1 or K2 running in the
US$2000 - US$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.
Due to their length (a K-1 is 5.2 m (17 ft) long and a K-2 is 6.2 m
(20 ft) 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 multi-person designs). In spite of this,
these boats have a fairly large
turning
radius.
Canoe sprint kayaks are closely related to sprint canoes, with both
styles of boat usually training at the same club or with the same
team, although it is rare for paddlers to compete in both canoes
and kayaks.
Surf Ski
A highly specialized variant of flatwater racing kayak called a
Surf Ski has an open cockpit and
can be up to 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 ocean races, lake races and even downriver
races.
Slalom kayak
Kayaks designed for
Slalom canoeing
have a relatively flat hull for maneuverability and—since the early
1970s—low profile decks.
Like all racing kayaks, they are usually made of fibre reinforced
resin (usually epoxy or polyester reinforced with kevlar, glass
fibre, carbon fibre, or some combination). This form of
construction is stiffer and has a harder skin than non-reinforced
plastic construction such as rotomoulded polyethylene: stiffer
means faster, and harder means fewer scratches and therefore also
faster.
Specialty and multi-type kayaks
The term "kayak" is increasingly applied to many craft that evolved
substantially from traditional kayaks.
Inflatable kayaks
Another special type of kayak is the inflatable kayak, also known
as the "ducky". 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" (see
above) overall design using multiple inflatable sections to produce
a seaworthy inflatable sea kayak.
Besides being portable, inflatable kayaks generally are stable with
a small turning radius and are 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 with a paddle. This allows the
kayaker to keep his or her hands free for steering the rudder,
fishing and other activities.
Multi-hull and outrigger kayaks
Traditional multi-hull vessels such as catamarans and trimarans
benefit from increased lateral stability without sacrificing their
speed but these advantages cannot be successfully applied in all
multihull kayak models
Outrigger kayaks, are
equipped with either a single or a pair of usually smaller hulls
(
outriggers) attached to the main hull to
provide additional stability, especially for fishing, touring and
kayak sailing.Twinhull sit-on-top and
sit-in kayaks have been on the market for many years. The
inflatable models are popular in whitewater and fishing
applications and the Polyethylene models in fishing and
recreation.
Fishing kayaks
While native people of the Arctic regions did not rely on kayaks
for fishing, in recent years sport fishing from kayaks has become
popular in both fresh and salt water, especially in warmer regions.
Specially designed fishing kayaks have emerged, with designs
similar to those of recreational sit-in and sit-on-top kayaks
characterized by very wide beams (up to 36 inches) that increase
lateral stability. Some fishing kayaks are equipped with outriggers
for this reason, and the newer twinhull models are stable enough to
enable paddling and fishing in the standing position. In the past
several years kayak fishing has become a huge sport. The popularity
has grown due to the ease of entry. Kayaks can be purchased
inexpensively and have little maintenance costs. Kayaks can be
stored in small spaces and launched quickly. Many kayak dealers
across the U.S. have started customizing their kayaks for
fishing.
Standing in Kayaks
While paddling in the standing position has been practiced for
centuries in canoes (including Umiaks, Pirogues, native dugout
canoes worldwide etc.) it is only recently that paddlers have begun
to paddle standing in kayaks as a recreational activity. This is
called 'Striding', and involves paddling wide, inflatable kayaks
down fast rivers while strapping the ankles to the kayak - similar
to what is being done with skis in snow sports.
Modern kayak design
Modern kayaks differ greatly from native kayaks in every aspect –
from initial conception through design, manufacturing and
usage.Today almost all kayaks are conceived as commercial products
intended for sale and not necessarily just for the builders’
personal use. While native kayak builders used their personal
experience in combination with knowledge they acquired from orally
transmitted traditions, modern kayaks are designed with CAD
(Computer Aided Design) software programs, often in combination
with naval design software, and in some cases with special kayak
design software.
A free stitch and glue kayak design software package is
available.
Modern kayaks differ greatly from native kayaks in usage and
therefore in shape: Nearly one of every three kayaks sold today is
a sit-on-top (SOT), which is basically a paddleboard equipped with
a seat. Unlike traditional kayaks many kayaks today are designed
for whitewater and surf applications, and are extremely short (some
measure less than in length). Other modern designs are extremely
wide (e.g. recreational, fishing). Some modern kayaks are equipped
with one or two extra hulls (outriggers) to increase their
stability, some have twin hulls (catamaran kayaks, W kayaks), some
are inflatable, and some are no longer propelled by the traditional
dual blade paddle (‘kayak paddle’) but by means of pedals that
activate a propeller (‘pedal kayaks’). In fact, some modern kayaks
are no longer using human powered propulsion at all but are sailed
(‘sailing kayaks’) or propelled by a trolling motor – usually an
electric one.
Even kayaks that copy traditional forms (e.g. monohull sea kayaks,
touring kayaks) are considerably different from the original native
designs that serve as inspiration for them: They are equipped with
specially designed seats and foot braces that no native kayak ever
featured, they are often equipped with a rudder system, which is
totally alien to native kayak design, and they feature bulkheads,
floatation, hatches and eyelets that native kayaks never had.Most
kayaks today including the ones inspired by ancient forms are
manufactured entirely from plastic resins or from such materials in
combination with other materials (e.g. synthetic fibers, plywood,
wood strips). This is why hardly any modern kayak features the
traditional frame made of ‘ribs’ over which native kayak builders
used to stretch sealskins sewn together.In sum, modern kayak
designs reflect the diversity in usage as well as the advancement
in design and manufacturing technologies.
Design of traditional style kayaks
The design of different types of kayak is largely a matter of
trade-offs between directional stability ("tracking") and
maneuverability, and between stability (both Primary stability and
secondary stability) and overall speed.
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 . A flat
water racing K1's maximum length governed by the
ICF is . 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 five to 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 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 rocker will be out of the water, so its
lengthwise waterline may be only . 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 led to whitewater kayaks with very flat planing
hulls that allow them to surf on top of moving water rather than
float in the water (displacement hull).
References
- Made in Anglesey, paddled in the Arctic: the Inuits'
plastic kayak rules the waves TimesOnline December
2006
- www.voelkerkundemuseum-muenchen.de
(English)
- D.C. Hutchinson, "The Complete Book of Sea Kayaking", 5th ed.,
Falcon Guides, Connecticut.
- Cockle Mark II
- Common Construction of a Sit on top kayak
See also
External links
.
Wikis
Quiz
Map
Search