Re: [Paddlewise] High Aspect Ratio Paddles

Peter T. wrote:

> Why don't all long distance paddlers use them, particularly if they are
> nearly twice as efficient?

I think mostly ignorance.  As I stated, fluid mechanics is a very complex
issue and not intuitive at all, so it is easy to fall victim to the
marketing of equally ignorant paddle makers, many who have built reputations
making perfectly fine racing or WW paddles (but unsuited to long distance
seakayaking).  Their experience or knowledge does not translate to the
different conditions.  Consider how different a sail plane wing is from a
fighter wing, different conditions, very different design.  Most who
PROPERLY learn how to use a high AR native paddle, usually stay with it.
But they do feel VERY different, and they are used differently (just like a
sail plane vs. a fighter aircraft), so many are not comfortable with a
native blade when they try it, and do not want to make the transition.  When
I first saw a Greenland paddle up close, my reaction was "how can you
generate any trust with a skinny stick like that?!".  It was years latter
that I read a detailed article about a guy who transitioned and found not
only less effort and less stress on his body, but also he was cruising at
the SAME SPEED with less effort.  If forced me to think through the stroke
mechanics, and what was actually happening at the blade.  It was quite a
revelation since it was not obvious even to me, who has many miles in canoes
since a child, and now more than a few in kayaks as an adult, and have spent
a good part of my professional career doing computational fluid mechanics.

Should the same paddler, paddling over the same
> distance in comparable conditions, expend nearly half as much energy with
a
> high aspect ratio paddle as with a low aspect ratio paddle? If so, this is
> such a dramatic difference that high AR paddles should take over for most
> toreros. But, they don't.

Again, ignorance, and fear too.  If "looks" odd to most who see what the WW
and racers are doing, and since it also feels very different in the hands,
most will not given a fair comparison or use the proper criteria in
measuring the value of the paddle.  Most consumers are greatly influenced by
the store sales clerk too.  Market acceptance is a very serious concern, no
matter how good your product is, if no one will buy it because it "looks
funny", you will go broke.  I know this from personal experience in more
than one industry.

> Putting it the other way, if a fit paddler was able to input greater
energy
> into paddling with a high AR paddle, shouldn't he or she go faster and
last
> longer than with a low AR paddle?

you are confusing terms.  NOT faster, or input of greater energy-- you will
expend LESS energy over the SAME distance, at the SAME speed, with the
higher aspect ratio of otherwise two identical paddles.  Or you could go
further with a given expenditure of energy, at the same speed (you might
notice this if you come to the point of being out of energy before it gets
dark).  So over the same distance you would have a greater reserve of energy
at the end of the day.  This is hard to measure in a recreational paddle
since most days vary any way.  And since almost no paddles are the same in
all ways except AR, you would have to specially make them this way to
compare them.

> Does anyone have experience of longer distance races where paddlers use
both
> high AR and low AR paddles? Who wins, and who is in best shape at the
finish
> line? If a race is not the best practical test, what is the speed cut-off
> point where a high AR paddle comes in? The equations seem to suggest that
> high AR paddles are more efficient at any speed, assuming an equal blade
> area.

Again you are confusing what I am saying (go back and reread my post).  Even
a long distance racer is trying to optimize distance over time (i.e.
absolute speed).  You need to measure energy out put (with perhaps an oxygen
uptake mask that measures total volume of air consumed), over a given
distance, AT THE SAME SPEED (and yes, any speed, as long as you are
comparing the same speed).  When you go faster, the hull drag goes up, you
must expend more energy to get there in less time, any type of race is not a
valid comparison.  Even different paddlers will expend energy in different
amounts, so you have to measure heart rates, or air consumption, with the
same paddler, with the same hull, at the same speed, with different paddles
of the same shape, area and weight, with different ARs.

I am willing to volunteer to assist with running such comparison tests of as
many paddles we can put together for a magazine article or equipment review
for anyone that wishes to put together such a comparison.  How about it
Matt?  Anyone at SK mag on the list?

> Am I paddling up the wrong creek with these questions?

Yes you are, as noted about.  IOW, these are the wrong questions, so how can
you expect answers that make sense if you, like most people, do not even
know what the right questions are?  Not your fault, it is just the general
lack of understanding of such complex issues as fluid mechanics.  Consider
that humans have been attempting to build flying machines since the dawn of
recorded history, perhaps 3000 years or more, yet it was only about 100
years ago that enough was understood to make the first controlled flight,
(and only some 40 years later fly faster than the speed of sound).  So the
technology required was not obvious, and not intuitive.  As an aside, it is
interesting to note that the design of the kayak has changed little in
perhaps 2000 or more years (except for the materials), and it is still a
pretty good design in general for moving long distances in changing and
often rough conditions over water by muscle power.  A remarkable
accomplishment.  And why I think often native designs, like the paddles, are
superior.

Peter C.

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