Re: Prop selection for 6 horse Sailpro
4800 is pretty close to the range, but you are pushing a lot of boat. If your motor was bought as a SailPro, it should have the "elephant-ear" prop, which is a 5.9999" (6") pitch. It is quite identifiable because the blades are big and "round" and flat. See the prop chart at
http://www.tohatsu.com/accessories/prop.html If you need even less pitch (for higher RPM), your local prop shop can probably flatten it out to maybe 5-1/2".
But I would rather you have the 2-cylinder 8 or 9.8 on that boat. The Catalina 25, at 4500 pounds, is not a lightweight sportboat. The smoothness of the 2-cylinder is very nice, plus the 4-blade HT props for the 8/9.8 really shovel a ton of water, giving excellent control, especially in reverse. FWIW, I have the 9.8 on our 7,000-pound HR-28 in my avatar. Works OK, and is the largest that will fit in the lazarette; a 15 would be a big improvement for us.