upper lip wing paddle what's the use ??

Hi ,

Can anyone tell me what's the use of the upper lip for a wing paddle ?
Some blades have big ones, some others small ones. So I'm curious about this.

Thanks

Marco

Try this, sit stationary in your boat with your wing paddle, do not pull back at all, simply move the paddle out sideways away from the boat for a half dozen strokes each side, your boat will move forward. This is what a wing does, the shape of the wing creates a low pressure area on the top and a high pressure area on the bottom creating lift, or forward motion in the case of a wing paddle.
Without the lip the paddle would flutter when moving to the side, when moving backwards it would spill water on the wrong edge creating turbulence. That's my understanding off it anyway.

The original wing paddles were a complete wing, as in a full aeroplane shape thing.
It was soon discovered that it could be made lighter without a loss in performance by simply leaving the back section off.

So what we are left with are the most important bits, the leading edge, whose depth and profile alter considerably the operation of the wing, and the rest of the blade with it's curved profile and width.

Much the same as a boat can have a transform without a real loss of it's overall profile.