Hi Jeremy_H Clearly I'm not alone in my thoughts on this idea. Is that your boat in the pic? I never considered a rigger with an air engine. Please understand I meant no disrespect to anyone's design or a person for what interests them in this varied hobby of rc merely exploring alternatives with available means of propulsion. I have seen some interesting creations here at rcu and it can certainly gets ones creative juices flowing that's for sure. I have built a 48" hydro and placed a 75 supertiger (inverted for lower CG) just behind the front sponsons at about 2 degree's up thrust and to be honest it scared the heck out of me, scary fast, too fast for fun unless the aim is to create the fastest water dragster. It was estimated to be over 70 mph in seconds and to my astonishment it actually worked with no sign of lift off, blow over and seemed to be exceptionally stable. Have you or anyone else experimented with this concept?, what was the outcome?, anyone have pic's of their creations?