Re: [Paddlewise] A new way to teach the forward stroke?

PeterO wrote:
> Something that's puzzling me is that the potential energy of a falling
> weight is directed vertically downwards and the kinetic energy will not be
> converted to forward movement  [...]

If I had answered that question in my video, it might have saved me half 
of the objections. Thanks for asking the right question.

While the arms move downward, the paddle-blade does not. Assuming you 
keep you elbows locked and move your arms down from the shoulders, both 
your hands and your paddleblades will travel in a circle around your 
shoulders. I made a drawing:
http://www.nibla.nl/tmp/paddlewise/halfway.gif

You see that, while the hands are moving down, the submersed blade is 
mostly moving backwards.

The force that the paddle produces is not in the same direction as the 
movement. We all know that it takes very little force to slice a blade 
through the water - anyone who tried to brace on a vertical blade has 
experienced it. The main force that a blade produces is always 
perpendicular to the surface of the blade. We use that characteristic in 
all our rudders, draw-strokes and sculls.

As shown in my drawing, halfway through the vertical-rest-stroke, the 
force is almost perfectly backward - as long as the blade is vertical in 
the water.

The beginning and end of the stroke are less efficient, as shown in 
another drawing:
http://www.nibla.nl/tmp/paddlewise/begin_and_end.gif
It nicely shows why you shouldn't make your stroke too long at the back.

> So I can see that your invention might work
> albeit probably with a very slight mechanical advantage.

My invention was never meant to make use of the gravity-stroke. I simply 
analyzed my own stroke from video, looked for the place of my arms and 
paddle with the smallest amount of movement, and thought that would be 
the best place to support the paddle. I noticed that there's a spot, in 
front of me at the height of my chest, where the paddle always moves 
through, so I made a support that allowed that movement.
It's quite clearly visible in a small animation on my website:
http://www.nibla.nl/peddeldrager/ (scroll down to the moving pictures)

It was long after designing the paddle-carrier that I thought up the 
vertical-rest-stroke. I'm happy to note that my invention extends on the 
same principle, but it's coincidence.

When watching the animation from my link, I see the center of my paddle 
rise and fall for about 30/40 centimeters, once more indicating about 
20/30 watts of power from potential energy. I maintain that most of the 
energy is going into backward force and movement, having nowhere else to go.
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