Re: Repower confusion (horsepower)
You might want to check out Dave Gerr's Propeller Handbook. The process there is to calculate the power to drive the hull, normally at hull speed. After that figure out the pitch. Then check blade loading. If it's too high then more blades (probably not an option for you), wider blades, larger diameter (limited by blade tip clearance). He gives you all the information and formulas to crank thru. I found Michigan Wheel had a good computer model and will do the calculations but it's good to do an independent one on your own to second check. It's a good point not to overpower. Diesels don't like to be run at less than about 70% power.