batboatracer

OK, I have a single engine I/O cat. Everyone I have talked to says 3 blade for more top speed, 4 blade for better holeshot and handling. I have been spinning a 21 pitch 3 blade mirage and geeting no top speed. Used a 27 pitch 3 blade mirage and gained 5 mph but could not spin more than 4700 rmp. So, a labbed 25 would probley be perfect. Here's the thing. I was looking at the newest powerboat mag and all of the sinle engine cats were spinning bravo one props. The Kilo record for F3 is with boavo one props. I also thing I need more bow lift. I don't think I'm packing enough air. I am in the market, so someone help me out please. Later Joe
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cobra marty

Where is your propshaft? That is, if you draw a line across the bottom of the sponsons on the inside edge- where does the propshaft/bullet lie. Measure it in inches either above or below this line. Also, What are you using for water pickup-side bravo, LWP bravo, offshore style p/u?

batboatracer

Going by memory here. I believe the prop shaft is about 2 inches below the sponsons. There is a 1 inch spacer in the drive. It is a standard side water pick up. Should this be upgraded? Thanks Joe

cobra marty

I remember and know the history of your boat but anyway think about it- the boat rides at speed with, at the most 2" of sponson in the water that is it rides about a line straight across the lower outside edge of the sponsons which is about 2" above the inner edge of the sponson. Now look where the water p/u holes are located-- well above the water line. At low speed you'll pick up water and at speed you will have no water and overheat. Your drive is also low but you need it there for the 3 blade prop. My prop is 5 1/2" above the lower edge of the sponson and use a B1 prop and it rockets/jumps out of the water onto plane. I use the LWP HP bravo drive and lose water at top speed and also use an offshore p/u.