I sold Joe the boat
J,Joe's 1980 27 came to me with the 3 blade prop and I don't know who put it on. I would suggest talking to a prop company. If you read the owner reviews, most of the Cherubini Hunters came under propped and were improved with the addition of a 3 blade prop. The improvement comes not from the number of blades though, but from the increased "driving surface". If you were to look at Joe's prop and compare it to the stock prop found on most of the Renaults and Yanmars, you would see that on the stock prop there is little surface coverage for the circumference that the blade swings through. The 3 blade prop blades are much larger in area. The down side is more drag when you're trying to sail. But let's be real, how much affect can the drag of several square inches cause? Kinda like sticking your hand in the water while sailing....do you think that will slow you down much? I guess if you are a racer, every little bit helps, but I can speak for Joes boat, Catalina 27s didn't stand a chance and I slipped by a C-30 on more than one occasion!