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Old 05-10-2006 | 11:54 AM
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Default What prop do I need?

Please be patient, I do not know a whole lot about props but I do know the one I have is not what I should be running. I have a 1987 28' Saber Offshore with a carburated 502 and Bravo drive with 1.5 RH gear. I do not know what the HP rating is and am assuming around 500hp. Engine has high rise aluminum intake, 950cfm double pumper holly carb, MSD distributor, IMCO manifolds. The prop that came with boat is a Mirage stainless 25 pitch 3 blade and when I am running wide open I'm only getting around 58-60mph and running at 4800-4900 rpm. I should be turning between 5200-5400 rpm shouldn't I? The boat (dry) and trailer weigh 6,450 lbs so I am assuming the boat weight approx. 5500-5600lbs dry. What should I try? Is this a prop problem or should I look at something else? Thanks for any info and please let me know if I can provide ant more info to help you guys answer. Thanks again in advance...
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Old 05-10-2006 | 08:38 PM
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Smile Re: What prop do I need?

I would think with your hp/wt ratio you should be able to turn the 25. However your slip is high and you can only turn 4850. I think there may be more than a prop issue. True horsepower is in question as well as what has been done to the propeller in the past. I can only assume your prop shaft is about 7" below the bottom suggesting the prop has a issue too.
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Old 05-11-2006 | 09:10 AM
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Default Re: What prop do I need?

More than a prop issue? Where do you think I am losing power? Engine seems to run strong...
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Old 05-11-2006 | 10:34 AM
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Smile Re: What prop do I need?

Maybe I talked to quick. If you go down to a 23 Mirage you will theoretically get the rpm's to your desired point. You may not see any increase in speed. So the slip may still be there. We don't know enough about the history of the propeller you now have. Originally my thoughts were that the hp you have should push a 25 a little stronger with the weight you are claiming. Try a smaller pitch propeller and it will teach you a bunch. Also, weigh the boat at a truck stop if possible to get a true wet weight.
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Old 05-11-2006 | 12:19 PM
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Default Re: What prop do I need?

I do have a 3 blade 23 pitch mirage that I can try and see what that does for my rpm range and any affect in speed. My buddy also has a 22 pitch 4 blade I could try if you think that would be a better match. I did get the boat weighed when it was on the trailer and it was 6400 lbs total. I have not been able to keep the boat in the water long enough to weigh just the trailer to get an exact weight of the boat. Also, what kind of difference should I expect other than turning more rpm's. Will it be out of the hole quicker, more/less slip? I guess I wont know until I try. Thanks again for the advice.
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