I used a 1 inch size radio shack fan mounted in a Walker Bulldog. Mounted where the speaker box was on top of the board blowing up, moved speaker back to where the smoker was, as it is removed. Engine sound is in the back now. Also drilled vent holes in bottom of hull, I know a lot of people are big on sealing the hull, but if it aint in water it aint no problem. Small fan draws little power, run time not reduced enough to speak of. Even though its a 12v fan it runs fine on 7.2v's. Oh it was wired in the smoker socket so it comes on on startup, and can be shutoff with the smoker switch if desired. When I get a digi cam Ill post some pics.