Rick wrote:
...stuff deleted

That's true, but...

The reason for this is that you don't need a lot of paddle in
the water to propel a boat.

...that's not the reason. If the issue were simply size, then why not
just use a smaller blade? The reason asymmetic paddles are asymmetric
is the the paddle is usually inserted at some diagonal angle to the
water. If the paddle is symmetric around the shaft line, you have more
paddle in the water below and less above, causing twist. The asymmetry
tries to compensate for that. If you use an asymm paddle upside down
(ie, the longer edge of the blade down), you create more, not less,
twist, thereby requiring a tighter grip on the paddle, thereby mucking
up your tendons.

I was not commenting on whether asymmetry will, as you say, reduce
turbulance, vibration, and cavitation. What I was saying was that you
don't need a lot of blade to propel a boat and that placing the wider
edge into the water will tend to result in excess work and stress for
the paddler (the blade, be it small or large, will only move a few
fractions of an inch when pulled against). Since we were discussing the
injury here, I was pointing out that the load of an inverted paddle may
result in undue stress on the paddler.

I said nothing about "turbulance, vibration, and cavitation", just
torque (i.e., twist). BTW, paddles don't cavitate, they ventilate,
(http://www.guillemot-kayaks.com/Design/Paddlework.html), but that's not
the point here. Yes, you don't need a wide blade to propel a boat. The
Greenlanders proved that over 2000 years ago. But I still don't follow
your point. Would you say it isn't good to totally immerse the blade? Or
that everyone should use narrow blades?

Perhaps you've never heard the arguments in favor of asymm paddles. Have
a look here for a nice explanation:
http://www.getoutcanoeing.co.uk/acat...ategory&page=1

--
Steve Cramer
Athens, GA