Grass Hopper, you would notice that I said that I did not know what kind of rivers that he intended to run, and with his type of boat...(a small jonboat) a prop would work just fine in a river such as the lower Chehalis for instance. I would not think of using one in a river like the nisqually or even the Cowlitz in low water conditions. And Grass Hopper, I suppose that your kicker is a jet too, probably not, wonder why?
Regardless, does he realize what can happen when that small boat is roaring along and hits something? I have seen this done in good sized sleds and even saw a guy and his dog go swimming once on the Cowlitz below the mouth of the Toutle.
By the way Grass hopper, know what happens when your sled sucks up too much of that grass....she's dead in the water....err grass!