prop size suggestions

DGIFF396

Seaman Apprentice
Joined
Jul 8, 2007
Messages
37
Its a 1978 lund with a mercruiser 470. Its a 4 cyl with a ford v-8 head on it so it pushes 170 h.p. The boat is fiberglass and according to N.A.D.A. it weighs roughly 2000 pounds. It has a mercruiser pre-alpha outdrive 1:1.85 ratio (i believe). At WOT the boat will reach 4500 rpm, not sure of speed cuz I dont have a speedometer. Heres the problem; I have a 3 blade prop and it looks like someone bit into each blade mistaking it for a juicy grilled burger. Sometimes while tubing or turning the prop will start to freespin(pushing water easier than catching it and propelling the boat), my question is simple, what prop would any one suggest, please give me the dimmensions, pitch, cup or whatever marine specific things so i can print it off and show it to the marina cuz IM a complete newbie to boats I would like a suggestion for the best size for carrying a fully loaded boat and able to tow a tuber (more tourqe im assumin) and also a suggestion for one that can give me the most top speed for cruising the mississippi with just the wife on a weekend get away (without over-revving) thanx alot
 

DGIFF396

Seaman Apprentice
Joined
Jul 8, 2007
Messages
37
Re: prop size suggestions

I havent gotten any replies yet and was hoping to pick the prop you know;edgable guys suggest tommorrow.....did I leave out vital information you need? PLease let me know cuz IM clueless
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: prop size suggestions

Yes, you did leave out some important information. Speed, current prop diameter (you can measure it) and pitch (look on the barrel of the prop or on the hub). Not knowing what you have now makes it only a guess as to what you need. And you are also asking for a prop that can only be a compromise between speed and power. You need power to tow things or carry a heavy load. That's provided by a prop with less pitch than one that provides the maximum speed. My suggestion would be to have the current prop repaired. The RPM at wide open throttle appears to be about right.
 

DGIFF396

Seaman Apprentice
Joined
Jul 8, 2007
Messages
37
Re: prop size suggestions

thank you....ill get the info in the morning and a picture of the prop cuz I agree I might wanna stick with same cuz boat seems fast enough and all and i bet after you view how awful this prop looks youde agree a new one would increase 15-20% power....thanks again..... see ya'll in the morning
 
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