Air screw driven hydro
Don't do it! Use a river or a public lake. We HAVE to middle finger the arseoles who would have us using electrics as a matter of course. Rivers and canals can be used with ease as the real thing is already dirtying up the water, which, of course, the wild life are well used to.
As an air boat would never be used that much anyway, keep it for when you travel to a river. Keep the electrickery for the Jobswuffs.
AM 15 is a great little motor. I used to have one. Alweays started easily. Trouble is these days the fuel ain't exactly cheap, but then, neither is a brushless motor, Li-Pos, special charger, watt meter, battery condition meter, special wires and connectors, and of course special ESC which will almost certainly burn out like they all seem to eventually.
Failing that put it on the shelf and await interested questions!
Martin