wrote in message
It
may have been invented already by somebody else, and I have not read
about it.

It has. Submarines use this technology to reduce cavitation and noise.

Either way, if I am the first, it is now a public domain
invention, for all to use!!!

As soon as you come up with a way to offset the added weight and complexity
(gotta ad a gear box there somewhere, ya' know) I'm sure you are sitting on
a million dollars, Doug. Got for it, buddy!

--
Jim Fisher