Price seems to be over $7K for the cheap version. I am wondering why you can't adapt an electric trolling motor. These are cheap, probably just as durable if not more so (I'm sure they make 100 times as many as Watt and Sea, so you aren't buying a prototype). I haven't looked closely as one, I assume they are electronically commutated so there may have to be some control electronics built. The most expensive ones you can buy are way less than $1k, some less than $200.