RE: [Paddlewise] Greenland Paddles - Seeing the Flow.

From: Steve Brown <steve_at_brown-web.net>
Date: Wed, 8 Sep 2004 19:00:47 -0700
I agree. 

Many-many (maybe too many) words follow.

The purpose of an airplane wing is to produce enough lift to hold the
airplane up in the air with minimal resistance to going forward. Going
forward efficiently in an airplane is all about the lift-to-drag ratio.

The main objective of the kayak paddle is ONLY producing lift (force
perpendicular to the paddle face). This is all about maintaining high lift
at high angles of attack. Analogous to an airplane wing used only for
climbing without forward motion as an objective.

The euro is obviously better for that. 

The "forward" motion of the paddle - the motion parallel to the blade
surface - does not contribute to forward motion of the kayak. It only
contributes to drag. This is working against the GL paddle.

On the other hand, as you point out about your joints, the human body is not
an indestructible machine.

All the anecdotal accounts on this list have substantiated the lower stress
of the Greenland paddle and a few (myself included) have experienced
slightly higher SUSTAINED cruising speeds.

Similarly, cyclists have minimum oxygen uptake at 40-to-60 RPM pedal
cadences. Any serious cyclist knows that peddling high outputs at those low
RPMs will destroy the knees in the long term and result in poor performance
in the short term. 90-to-110 RPM is the norm.
I first read about this in the 80s, but in the meantime other tests of body
stress have been put to use:
http://www.uth.tmc.edu/apstracts/2000/regulatory/October/355r.html

That abstract and some other articles I looked at indicate that the extra
stress on the body at lower RPMs is measurable, even if the oxygen uptake is
lower for a given load.

I'm guessing the same is true of paddling as with cycling. It's not just all
about efficiently converting oxygen and fuel into forward motion. 

I didn't read any of the cycling articles all that carefully, but what I
gleaned was that for long high intensity rides, oxygen uptake was not the
limiting factor. Therefore, minimizing oxygen uptake was not necessarily the
way to maximize performance.

I never seem to paddle anywhere near my maximum aerobic output. The
limitation seems to always be in my muscles and joints, not my heart and
lungs. Somehow, over distance, the Greenland paddle may be more efficient
for the whole body system.

I wonder if any careful studies have been done on this as they have for
cycling?

This is not about winning races. Lets assume that gear has evolved recently
to give the fastest speeds over race distances. This is about efficient pain
free paddling over a lifetime.

Did Inuits stumble on the narrow blade because they didn't have many big
pieces of wood, or did they find by experience that they couldn't afford to
have their bodies break down at the expense of being marginally faster for a
few years?

Steve Brown
 

-----Original Message-----
..........

Test evidence includes tank tests that show efficiency increases as 
aspect ratio decreases.  The theoretical is limited to the 
observation that moving large amounts of water at low velocity is 
more efficient than small amounts moved fast.  It would appear that 
the GP does more of the latter.
........

Mike
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Received on Wed Sep 08 2004 - 19:01:15 PDT

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