OK I have herd spin up re' diameter and max prop RPM /and same thrust less rpm with more pitch. Like i'm wondering what I have to keep an eye open for to finish this boat. But would be really good is if everyone could get a good idea what diameters and rpm /pitch can do for you. Really engine and boat reactions to the different DRIVE Options (direction) as well as RATIO'S and length from crank to prop and really didnt need to be LAST, Counter rotating! :lol: