[Paddlewise] paddles

Please excuse me for not following every post on this so maybe I have missed
something. Nevertheless I will try to add some clarification to the issue.

Every post that I have read so seems to base conclusions on actual paddling.
I would caution you not to draw to many conclusions about physics from this
kind of experimentation or experience. There are simply too many variables.
How do you know if your output is exactly the same, what about boat
differences, emotional differences and maybe the people you are paddling
with just aren't in a hurry (or are). This kind of "test" involves an almost
infinite number of variables from which one hopes to draw a single
conclusion.

The physics are well known (in fluid dynamics circles anyway) -  the
biomechanics are less well understood. The one thing that researchers have
found is that human perception does not win any awards for accuracy. Anyone
intersted in this kind of thing can read the various books on
psychokinetics. Very sobering to me after thinking for years how accurately
I could assess a boats performance just by paddling it and the reason why I
developed KAPER.

One writer wrote:

> The only thing I can think of is that boat speed through the water must
>have something to do with it. When the boat speed is low and the paddler is
>applying lots of effort, the higher aspect ration blade with more slippage
>is not going to be as efficient. However, as boat speed increases to the
>point where its closer to the paddle speed, slippage becomes less of a
>factor -- or, at least, so I surmise. Going back to my other post, where I
>talked about paddling into a steep wind, would this account for the high
>stroke rate and not going anywhere?

In drag mode slippage is a major factor in thrust production regardless of
the boat speed. It is through slippage that you produce thrust. The more
paddle velocity (or slippage) the greater the thrust. As I said before,
"slippage" is an unfortunate word as it seems to have negative connotations
regardless of cases. Sometimes slippage is positive and sometimes negative.
In the case of paddles it is usually positive.

 In the case of the lift mode slippage is still essential to develop the
angle of attack. The only time that I can think of where slippage is an
absolute negative facor is when the paddle ventilates.

Keep in mind that paddle blade efficiency has nothing to do with
biomechanical efficiency. I believe this is what causes so much confusion
for "real life" testing. A paddle with the greatest efficiency may not match
the paddler's biomechanically efficient stroke and rate. When that happens
we should not assume the paddle is "bad" but rather examine if the
paddler/paddle combination does work. The same paddle for another person may
be wonderful.

Regarding padldling into the wind one has to be certain about what causes
the lack of progress. Pitching is a huge robber of energy not to mention the
windage of boat , paddler and paddle. Without knowing all the circumstances
etc. one cannot know what to attribute a lack of progress to.

I can think of  one good example where the paddle cause a lack of headway in
head winds. Suppose when paddling into a heavy head wind the windage etc.
slows you to a crawl. Frustrated you add more power. If your paddle is too
small then it might ventilate and the thrust diminishes accordingly. In this
case the harder you work the worse off you are because the paddle simply
ventilates more.

Sorry if this is cryptic. Not enough time in the day to write more.

Cheers,

John Winters



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