Hmmm ok....we'll let you slide this time. Is that the Fork Tail Devil kit your talking about(the profile P-38). I dont remember the manufacturer, but the LHS has(or had) one that one the box...it said fly the forked tail devil.

E-flite makes really light floats for use with their Electric Piper cub. Maybe those would work. Here is link...my LHS has a set on the shelf right now.
http://www.horizonhobby.com/Products...ProdID=EFLA500

If its not floats thats the problem, but lack of power, well....if your running glow motors, I dont know what to tell you unless you want to increase the motor size.....or maybe try different props.