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Mirage vs Bravo

Old 05-28-2015 | 08:10 PM
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I believe we have the same dyno guy, Full Throttle Marine. What boat do you have ? can you measure your propshaft height ? I think we can trade a lot of information.

Originally Posted by Captain YARRR
I have twin 400 HP 383s, Mirage Plus 23s. Not sure on X dimension. Keep getting over speed on port when I start to trim out.
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Old 05-28-2015 | 08:32 PM
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Originally Posted by thirdchildhood
If switching to a Bravo 1, go up in size one pitch. They tend to be over-rated. A 26p Bravo should keep you in the same rpm range as the 25p Mirage. I had to find this out the hard way. I'm running a 30p Bravo 1 with 1.5 gears and I doubt I could pull a 30p in any other prop. I think you should try one. The shorty worked great on my boat and if you do that you will almost certainly need four blades. I don't know how the shorty will work on a 29' boat though as you will lose bow lift due to less leverage (higher prop).
I always thought that was the opposite.... since 4 blades have more bight they take more to turn so if you have a 25 3 blade you would need a 24 4 blade...
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Old 05-28-2015 | 09:42 PM
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Originally Posted by phragle
I always thought that was the opposite.... since 4 blades have more bight they take more to turn so if you have a 25 3 blade you would need a 24 4 blade...
Yes, what he said!
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Old 05-28-2015 | 10:18 PM
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hey if you are getting 9% slip on a big V-bottom that sounds pretty darn good.
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Old 05-28-2015 | 11:41 PM
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Bravo props do measure about 1" smaller actual pitch than their rating; how they hook up (slip at various RPMs) can be different for every boat.
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Old 05-29-2015 | 09:18 AM
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Originally Posted by 01scarab29
I believe we have the same dyno guy, Full Throttle Marine. What boat do you have ? can you measure your propshaft height ? I think we can trade a lot of information.
Yeah we do, we have talked before. I'll have to measure next time I'm with my boat. Maybe someone knows stock 6.2 prop height.
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Old 05-29-2015 | 02:19 PM
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Originally Posted by SFOcean
Bravo props do measure about 1" smaller actual pitch than their rating; how they hook up (slip at various RPMs) can be different for every boat.
Agreed. Every application desires certain propeller geometry for certain performance goals. One prop design will propel a boat but specific goals can improve by changing props.
I also agree the reported 9% slip can potentially be left alone unless you are desiring better cruise speeds or planning.

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Old 05-30-2015 | 07:45 PM
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My desire is getting the most out of what I have. I'm 7 3/8 deep and wondering if I install -2 Imco's what prop would be looking for. In a somewhat perfect world... And will a -3 Imco bolt to a Bravo1?

Originally Posted by bbladesprops
Agreed. Every application desires certain propeller geometry for certain performance goals. One prop design will propel a boat but specific goals can improve by changing props.
I also agree the reported 9% slip can potentially be left alone unless you are desiring better cruise speeds or planning.

Brett
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Old 06-01-2015 | 07:10 PM
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Originally Posted by 01scarab29
My desire is getting the most out of what I have. I'm 7 3/8 deep and wondering if I install -2 Imco's what prop would be looking for. In a somewhat perfect world... And will a -3 Imco bolt to a Bravo1?
As you raise X dimensions, additional blades can be required to get the best planning and trim reaction. Especially on V bottom boats.
The -3 should work. Contact IMCO with questions.

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Old 06-01-2015 | 08:15 PM
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For a -3 lower, you either need an Imco upper designed for it or you need to have a stock Bravo upper cut and modified.

http://www.imcomarine.com/cal_store/...e-3-black.html

Raising the propshaft 3" is a ton. I'd go -2's max.
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