Your rudder drawing shows potential, Jake! How would it suffice against those monster jellyfish at 20+ kts? Or maybe even a loggerhead turtle? In those situations, the rudder would be in the full down position. Would that place undue stress on the upper gudgeon?

I presume you'd control the depth of the blade with lines akin to the Nacra or SuperCat system? Who's job would that be while surfing down a 6'+ wave with the spin up?