I am building a Corvair engine for an airboat. I am pretty much following the conversions used for experimental aircraft. I am told that realistic HP is going to be around 100 horsepower give or take. I have posted about the corvair engine on this post before and appreciate the help. What I am stuck on is how much boat can i realistically push with this engine. I am not going to run dry, only swampy areas chocked off with vegetation (hydrilla and such) BUT, I will be in deep water most of the time. I would love to get fair performance with a large john boat style hull so I can still put some gear in and fish or whatever. Any input??? Thanks, Fred in SC