On 11-Jul-2004, Rick wrote:

My paddle cavitates when I pull hard. It goes in clean, takes no air
down with it, and it generates air bubbles on the low pressure side of
the blade, which is, by definition, cavitation (cavitation is not
limited to propeller blades, but occurs much more frequently due to the
intense pressures the blade places on the water).

Intense pressures? If you can cause a paddle blade to cavitate, you're
the most powerful paddler the world has ever seen. BTW - cavitation bubbles
are not air - they are water vapour. And they collapse almost immediately.
Check the damage on your blade. The collapse will cause severe pitting.

A paddle has an area of 80-120 sq in, typically, with some bigger still.
If yours is, say, 100 sq in and you generate an average of 0.5 psi on the
back side, that's a total force of 50 lb. It takes most fast sea kayaks
less than 14 lb to hit hull speed.

Please provide a reasonable pressure profile that will generate a peak
of 15psi and an average of less than 0.15 psi (that's a 100:1 spread).

Paddles ventilate. End of story.

Mike