From: kork@imagelan.com (Kirk Olsen)
Message-Id: <9503151446.AA17685@imagelan.com>
Subject: Traditional Paddles new thoughts
To: baidarka@imagelan.com
Date: Wed, 15 Mar 95 9:46:35 EST
> From: Guillemot@aol.com
>
> Since I instigated the discussion that resulted in the two-part synopsis I
> just posted, I have thought about the wide-vs-narrow problem further. "Wide"
> and "narrow" are both relative terms that probably oversimplify the
> differences between modern paddles and "traditional" designs. However, most
> of the paddles shown in Zimmerly and Chappelle have a relatively narrow blade
> length-vs-width proportion when compared to modern kayak paddles. Especially
> when compared to white water paddles. Most of the proponents of the
> traditional paddles refer to the "greenland style" paddles when speaking of
> the advantages of the traditional designs.
>
> I have become convinced that the lowered wind resistance of the atributed to
> the narrower blade is a red herring. I typed the paddle dimensions on pg 16
> of Zimmerly into my CAD program. From this I compared some measurements with
> a "wide" paddle of my own design. Where "Z" is the Zimmerly paddle and "N" is
> mine:
I agree that wind resistance isn't a successful argument for the narrow bladed
paddles.
> Assuming both paddles are used unfeathered (I generally build to a 70 deg.
>
> Area of the paddle face:
> Z: 100 sq in
> N: 112 sq in
>
> Assuming both paddles are used unfeathered (I generally build to a 70 deg.
> feather), my wide blade has only 12% more frontal area exposed to the wind.
> All other things being equal this is not a huge difference.
>
> Now start paddling. Because of the smaller paddle area, the narrow blade must
> be moved faster through the water to generate the same force. The force
> applied to the water is a function of the velocity of the paddle through the
> water.
Cavitation of the blade, length of paddle stroke, and percentage of the
blade submersed also need to be considered here. I find it rare that
I use the entire blade on my greenland style paddle.
Excessive force or an improper paddle plant lead to cavitation and wasted
effort.
> At the same time, the force the air applies to the paddle is also a
> similar function of the paddles velocity through the air. As best I can
> figure on the back of an envelope, the higher paddle speed required to create
> a given propulsion will result in an increase in wind resistance such that
> the wind induced drag of the narrow and the wide paddle is about the same.
>
> What I think is more important than the wind resistance question is the
> paddling cadence used. Racing cyclists like to maintain a high cadence a
> kayak paddler would see the same advantages.
When racing canoes we keep a stroke rate of about 70 strokes per minute
switching sides every 3 to 8 strokes. This cuts down on the muscle
fatigue and amount of correction necessary to keep the boat going straight.
Periodically we will shift to "power strokes". The power strokes are
very long slowed down strokes, about 30-40 strokes per minute, which
take a tremendous amount of effort. These increase the speed of the
boat but I can't maintain them for much more than 100 yards.
In both cases paddling technique is critical. It's easy to increase
the cadence by decreasing the amount of blade in the water but that
is counter productive with regard to the speed of the boat. Also a
canoe paddle should be vertical during the stroke, a paddle shaft
leaned to the side results in some of the forward force being lost
to sidewards force. I expect a similar situation with a kayak
paddle - portions of the forward stroke which are actually a sweep
are wasted effort with regard to straight ahead speed/power.
> Blade area effects the cadence. I think the force applied will be
> approximately inversely proportional to blade area. In other words the
> cadence required to go a given speed is also inversely proportional to blade
> area. Another factor affecting the paddling cadence is the effective length
> of the paddle. This will be related to the location of the center of effort
> of the paddle which should be near the geometric center of the blade.
>
> Distance from center of shaft to geometric center of blade:
> Z: 33 in
> N: 39 in
>
> The cadence needed to go a given speed should be inversely proportional to
> the effective length of the paddle. Given the area and effective length of
> the two example paddles, this suggests a paddler using Z would have to paddle
> at a cadence about 30% faster than when using N to go the same speed. This
> probably an advantage. Bicycling I peddle at a cadence in the mid 60s to 70
> rpm, a racer uses up near 100. I'm not sure what this means, but it suggests
> a professional can maintain a 30% higher cadence then a novice and benefit
> from it.
When mountain biking I find my cadence frequently exceeds 100 rpm. But a
high cadence makes it drastically easier to climb hills since smaller amounts
of energy need to get expended on each pedal stroke.
> What becomes important is what cadence is a given paddler comfortable at when
> paddling. Can the paddler maintain that cadence all day? I think there is an
> advantage to the average paddler to use a paddle that promotes a higher
> cadence. I also think that the original kayak builders would have had no
> problem maintaining a comfortable fast cadence even with todays wide paddles.
> Observe the Finlandia Challenge paddled with modern long, wide "wing"
> paddles.
Personally I prefer a traditional narrow paddle for long outings but
use a wider paddle when quick bursts of speed and power are important.
--- kirk olsen kork@imagelan.com imagine LAN Inc. Nashua NH USA (603)889-5889