Prop for 38
William; The usual practice is the same diameter as the 2 blade, but with less pitch. For example, my C36 had a factory 2 blade prop of 15x10x1, and the factory 3 blade was 15x9x1. The 15 is the diameter, the 9 is the pitch, and the 1 is the shaft size. You will need to know the shaft size and the taper. I have read in the C36 IA of where owners have increased the pitch on the 3 blade to 11 inches with good results, so I would be inclined to try at least the same pitch as the 2 blade. A Catalina dealer, or the factory should be able to provide the information specific to the 38, if you aren't able to get help here. Good luck. Michael
