Re: Overpropped; What to do?
Give her full throttle, then back off slightly. If it slows down you are not overpropped., If you have to back the throttle off a long way before it begins to slow down, you are over propped.You can either cut it down or pitch it down. Ask what others are using on similar sized boats with similar sized engines and reductions.Pitch is not hard to calculate with a pocket calculator. Charts on diameter are available in books like Skenes Elements of Yacht Design.
Brent Swain, Boat designer, Builder, and author of "Origami Metal Boatbuilding"