Cool! So why isn't anybody doing it? I believe a traditional sail is faster. They can be made to go nearly 1/2 the speed of the wind, even upwind taking into account the extra distance of tacking. A fan to push a boat thru the water can barely go 1/2 speed when it is going perpindicular, whereas a sailboat can go twice the speed of the wind.
Last month I sailed up the Colorado River rapids in Colorado!