Greenland Rolling Throughout Recorded History
by Martin Nissen
THE KAYAK - A Study in Typology and Cultural History
by Jarmo Kankaanpää
The Women Kayakers of Greenland [PDF]
by Martin Nissen
H.C.Petersen - An Invaluable Admirer of the Greenland Kayak [PDF]
by Martin Nissen
Grønlandske skindkajakker i Nordeuropa
by Martin Nissen
Preserved Greenland Skin Kayaks of the World
[PDF]
by Martin Nissen
Innovation
or Hyperbole?
by John Winters
What would you do to improve the design of kayaks? More
importantly, what can you think of that would have a dramatic (or at least
noticeable) effect on kayak performance an effect you could legitimately
call an innovation?
Excluding technology that allows stronger and lighter boats and
the paddling gadgets we seem to love, advances in hull design (although they
seem obvious to those who write advertising copy) have had so dramatic an impact.
In some cases, unique hull shapes have had negative results. In most cases,
so-called revolutionary designs amount to nothing more than incremental
development. Nevertheless, some developments in kayak design have altered the
face of sea kayaking and I will address those later. For now it will pay to
investigate some aspects of design development.
To illustrate why hull design advances dont appear every day
let me relate a story.
A number of years back Eugene Arima asked me to analyze a wide
range of native craft. The study encompassed hydrostatics, stability and
performance not unlike the studies designers do of competitors boats to
see how a new design stacks up.
As I analyzed the boats unmistakable patterns emerged and an
unexpected uniformity existed. This surprised me given the time and distance
separating the builders. Was it possible that, given a lightweight boat and
pointed ends, designing a good boat came naturally and didnt require any
knowledge of fluid dynamics? The virtues of simplicity and purity of form
appeared to take precedence over the latest fad or tortured shape promoted by
specious and hyperbolic advertising. The idea had a fascinating prospect.
To test the theory I "designed" a kayak without
resorting to any hydrodynamic theory. To this end I established rough parameters
of overall length, beam, and depth. Then I defined an amidships section by more
or less randomly picking a point for the chine. Using these points I drew curves
to define basic hull shape. Next I added two stations dividing the hull roughly
into quarters. I used these to provide enough room for my feet and increase the
deck area aft for gear. This time I picked chine points to provide flare similar
to the centre section and to avoid forcing the wood into an "unnatural"
curvature. Allowing the chine to take on a similar curve to the sheer defined
the amount of overhang; influenced the amount of rocker, and, to some degree,
the shape of the stems. I tweaked the final stem curvature to suit my aesthetic
preference.
The lines of the completed boat are shown in Figure 1 and bear
more than a passing resemblance to native craft.
Granted that my training and my familiarity with traditional
boats certainly influenced me in choosing my chine points. Nevertheless, an
Inuit builder would have drawn upon his experience as well and I carefully
avoided applying any hydrodynamic knowledge in the design. The only definitive
guidelines came from the arbitrarily set dimensions, the size of my feet, the
width of my behind, and what seemed like a reasonable deck area for carrying
articles aft of the cockpit. The hydrostatic analysis provided the moment of
truth. Were the numbers "good" and what would they tell me about my
kayak?
Here they are in abbreviated form.
Length 17.0 Waterline Length 15.09 Beam 1.58 Waterline
Beam 1.36 Prismatic coefficient 0.52 Block coefficient 0.40 Displacement 200
pounds Longitudinal Center of Buoyancy 49.5% Wetted surface 18.76 Square feet
In every category the numbers approach the average for
traditional Greenland style kayaks. More importantly they do not deviate much
from modern practice for good performance. In short, the boat has all the
indications of being a good kayak in spite of myself. It seems like, to create a
"bad" boat I would have to work at it.
Clearly this reveals that any new design must start from a high
level. Any further improvements must become increasingly difficult as one gets
closer and closer to the perceived ultimate. We can find a good example of how
difficult improvement becomes from GODZILLA, a program developed by Leo
Lazauskas of the University of Adelaide. GODZILLA starts with a "seed"
shape and then modifies it incrementally to develop a boat with less resistance.
It will do as many iterations as the user asks but after about 20,000 or so the
improvements, if any, grow extremely small. Interestingly one can use a wide
variety of shapes as a seed and get different shapes that have similar
resistance.
Many manufacturers claim that their boats unique features that
produce improved performance. For example, one claimed that their bow shapes
maintain laminar flow longer thus reducing resistance. They dont say longer
than what but one must assume longer than competitors. This would truly qualify
as an innovation if they could back it up. Examination of their hull shapes
reveals nothing
special so we can justify some
scepticism about the claim. Another builder claimed wonderful things for its
transom stern. Transoms are nothing new to naval architecture so we have lots of
information about what works, what doesnt work and why. Evaluation of the
boat using a performance prediction program revealed that the transom most
likely did more harm than good at cruising speeds and probably didnt help at
higher speeds. Kayak builders often overstate the merits of chines as well but
no claim has more than anecdotal support. Chines do affect handling (as do shape
variations on round bilge boats) but whether any boat handles better than all
others is a moot point. The boats associated with these claims may be decent
boats with a strong following. They may even be superb boats but that does not
make the claims valid and we should not confuse a well-designed boat (whether by
intention or accident) with novelty. In some ways modern boats have gotten
better. If builders have done nothing else they have recognized that one
configuration and one concept does not fit all. Unfortunately one must try a lot
of boats to find the one that fits "best" and that assumes the paddler
knows what constitutes "best" and how to evaluate it. I look with
scepticism upon "experts" who can paddle a boat for a few minutes and
pronounce judgement on it. Indeed, so many builders claim their boats are the
"Best" that the word has lost all meaning. The best of what? By what
criteria? By whose criteria? Superiority and design breakthroughs come easy to
those who write ad copy. Most "great" boats come from the fortuitous
meeting of the right boat with the right paddler. So, have there been any
innovations in kayak design in the past century or so? Speaking as designer and
a cynic I would list these as the significant design innovations (not in any
order of importance) in sea kayaks: The
first folding sea kayak. The
first sea kayak actually designed to a specific displacement. The first sea kayak that did not mimic
traditional boats. The
first sea kayak with a hull designed to fit a specific power output. The sit-on-top sea kayak. The first and last
cant be classed as hull design innovations but they did change our thinking
about what a kayak "is" and I dont feel like it stretches the point
too much to include them. This is not a big list and maybe I have too small an
imagination. In any case, each of us has the opportunity to find the right boat
for ourselves and when we find that boat it may seem like a breakthrough in
our own minds.
Published with the
permission of John Winters
by Jarmo Kankaanpää
The Women Kayakers of Greenland [PDF]
by Martin Nissen
H.C.Petersen - An Invaluable Admirer of the Greenland Kayak [PDF]
by Martin Nissen
Grønlandske skindkajakker i Nordeuropa
by Martin Nissen
Preserved Greenland Skin Kayaks of the World
[PDF]
by Martin Nissen
Innovation
or Hyperbole?
by John Winters
What would you do to improve the design of kayaks? More
importantly, what can you think of that would have a dramatic (or at least
noticeable) effect on kayak performance an effect you could legitimately
call an innovation?
Excluding technology that allows stronger and lighter boats and
the paddling gadgets we seem to love, advances in hull design (although they
seem obvious to those who write advertising copy) have had so dramatic an impact.
In some cases, unique hull shapes have had negative results. In most cases,
so-called revolutionary designs amount to nothing more than incremental
development. Nevertheless, some developments in kayak design have altered the
face of sea kayaking and I will address those later. For now it will pay to
investigate some aspects of design development.
To illustrate why hull design advances dont appear every day
let me relate a story.
A number of years back Eugene Arima asked me to analyze a wide
range of native craft. The study encompassed hydrostatics, stability and
performance not unlike the studies designers do of competitors boats to
see how a new design stacks up.
As I analyzed the boats unmistakable patterns emerged and an
unexpected uniformity existed. This surprised me given the time and distance
separating the builders. Was it possible that, given a lightweight boat and
pointed ends, designing a good boat came naturally and didnt require any
knowledge of fluid dynamics? The virtues of simplicity and purity of form
appeared to take precedence over the latest fad or tortured shape promoted by
specious and hyperbolic advertising. The idea had a fascinating prospect.
To test the theory I "designed" a kayak without
resorting to any hydrodynamic theory. To this end I established rough parameters
of overall length, beam, and depth. Then I defined an amidships section by more
or less randomly picking a point for the chine. Using these points I drew curves
to define basic hull shape. Next I added two stations dividing the hull roughly
into quarters. I used these to provide enough room for my feet and increase the
deck area aft for gear. This time I picked chine points to provide flare similar
to the centre section and to avoid forcing the wood into an "unnatural"
curvature. Allowing the chine to take on a similar curve to the sheer defined
the amount of overhang; influenced the amount of rocker, and, to some degree,
the shape of the stems. I tweaked the final stem curvature to suit my aesthetic
preference.
The lines of the completed boat are shown in Figure 1 and bear
more than a passing resemblance to native craft.
Granted that my training and my familiarity with traditional
boats certainly influenced me in choosing my chine points. Nevertheless, an
Inuit builder would have drawn upon his experience as well and I carefully
avoided applying any hydrodynamic knowledge in the design. The only definitive
guidelines came from the arbitrarily set dimensions, the size of my feet, the
width of my behind, and what seemed like a reasonable deck area for carrying
articles aft of the cockpit. The hydrostatic analysis provided the moment of
truth. Were the numbers "good" and what would they tell me about my
kayak?
Here they are in abbreviated form.
Length 17.0 Waterline Length 15.09 Beam 1.58 Waterline
Beam 1.36 Prismatic coefficient 0.52 Block coefficient 0.40 Displacement 200
pounds Longitudinal Center of Buoyancy 49.5% Wetted surface 18.76 Square feet
In every category the numbers approach the average for
traditional Greenland style kayaks. More importantly they do not deviate much
from modern practice for good performance. In short, the boat has all the
indications of being a good kayak in spite of myself. It seems like, to create a
"bad" boat I would have to work at it.
Clearly this reveals that any new design must start from a high
level. Any further improvements must become increasingly difficult as one gets
closer and closer to the perceived ultimate. We can find a good example of how
difficult improvement becomes from GODZILLA, a program developed by Leo
Lazauskas of the University of Adelaide. GODZILLA starts with a "seed"
shape and then modifies it incrementally to develop a boat with less resistance.
It will do as many iterations as the user asks but after about 20,000 or so the
improvements, if any, grow extremely small. Interestingly one can use a wide
variety of shapes as a seed and get different shapes that have similar
resistance.
Many manufacturers claim that their boats unique features that
produce improved performance. For example, one claimed that their bow shapes
maintain laminar flow longer thus reducing resistance. They dont say longer
than what but one must assume longer than competitors. This would truly qualify
as an innovation if they could back it up. Examination of their hull shapes
reveals nothing
special so we can justify some
scepticism about the claim. Another builder claimed wonderful things for its
transom stern. Transoms are nothing new to naval architecture so we have lots of
information about what works, what doesnt work and why. Evaluation of the
boat using a performance prediction program revealed that the transom most
likely did more harm than good at cruising speeds and probably didnt help at
higher speeds. Kayak builders often overstate the merits of chines as well but
no claim has more than anecdotal support. Chines do affect handling (as do shape
variations on round bilge boats) but whether any boat handles better than all
others is a moot point. The boats associated with these claims may be decent
boats with a strong following. They may even be superb boats but that does not
make the claims valid and we should not confuse a well-designed boat (whether by
intention or accident) with novelty. In some ways modern boats have gotten
better. If builders have done nothing else they have recognized that one
configuration and one concept does not fit all. Unfortunately one must try a lot
of boats to find the one that fits "best" and that assumes the paddler
knows what constitutes "best" and how to evaluate it. I look with
scepticism upon "experts" who can paddle a boat for a few minutes and
pronounce judgement on it. Indeed, so many builders claim their boats are the
"Best" that the word has lost all meaning. The best of what? By what
criteria? By whose criteria? Superiority and design breakthroughs come easy to
those who write ad copy. Most "great" boats come from the fortuitous
meeting of the right boat with the right paddler. So, have there been any
innovations in kayak design in the past century or so? Speaking as designer and
a cynic I would list these as the significant design innovations (not in any
order of importance) in sea kayaks: The
first folding sea kayak. The
first sea kayak actually designed to a specific displacement. The first sea kayak that did not mimic
traditional boats. The
first sea kayak with a hull designed to fit a specific power output. The sit-on-top sea kayak. The first and last
cant be classed as hull design innovations but they did change our thinking
about what a kayak "is" and I dont feel like it stretches the point
too much to include them. This is not a big list and maybe I have too small an
imagination. In any case, each of us has the opportunity to find the right boat
for ourselves and when we find that boat it may seem like a breakthrough in
our own minds.
Published with the
permission of John Winters
H.C.Petersen - An Invaluable Admirer of the Greenland Kayak [PDF]
by Martin Nissen
Grønlandske skindkajakker i Nordeuropa
by Martin Nissen