Thanks for link to patent.

Of course the device will work in an indoor tank with carefully controlled wind velocities.

Do you have the faintest idea what waves driven by gale force winds look like?

I can imagine it would be a pretty big wave.

But the Mech. Eng guys knew exactly what this kind of wave was like and did many experiments (using the wave tank, of course) that proved the survivability and efficiency of the Duck (pdf warning).  Now make sure your read it this time.

Thanks for link to patent.

I did not find "the" patent.
Just did a quicky search for the named inventor.
There were more than one that matched for Stephen S...

go to uspto.gov
pick patent search
pick advanced search
use the "in/" specifier to formulate a boolean search that includes the named inventor

also, the Wikipedia "Wave Power" page has a reference to the original 1976 patent for the Duck credited to just Stephen Salter.