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-   -   ooking for advice on 98 29 scarab twins (https://www.offshoreonly.com/forums/prop-talk/282391-ooking-advice-98-29-scarab-twins.html)

Adamcoover 08-08-2012 09:25 AM

ooking for advice on 98 29 scarab twins
 
I currently have 23 pitch mirage three blae props.

I run 68 and about 4800 rpms

I would like some more speed

What are the benifits to a four blade prop?

If switching to a 4 blade prop which pitch?

I have twin 350s on Bravo 1 Drives

Engines and exhaust, intake, quick fuel carb and cam nothing radical.

Adamcoover 08-08-2012 03:59 PM

Any help??

Adamcoover 08-09-2012 06:57 PM

somebody out there has to know something.... Right???

Wes Burmark 08-09-2012 08:22 PM

Adam I am no prop expert. My Fountain has 4 blade Bravo 1 props. It is my understanding (from reading advice from folks who go fast on OSO) that you need to drop an inch or so of pitch when you go up a blade. There are two supporting vendors on this site that do nothing but custom props for a living; B Blades and Cutting Edge. Customers of both vendors have great things to say about both vendors. They answer email so I suggest you go to the pros. Good luck.

hotjava66 08-09-2012 08:50 PM

Generally going from 3 to 4 blades you lose a bit up top but gain in low/mid. No experience with your hull so not positive but that is generally the case in a straight bottom v hull.

Adamcoover 08-09-2012 09:03 PM


Originally Posted by hotjava66 (Post 3750369)
Generally going from 3 to 4 blades you lose a bit up top but gain in low/mid. No experience with your hull so not positive but that is generally the case in a straight bottom v hull.

I was un aware of loosing top end. She's got plenty of grunt now so maybe a 4 blade of the same pitch?

supermx96 08-09-2012 10:16 PM


Originally Posted by Adamcoover (Post 3750386)
I was un aware of loosing top end. She's got plenty of grunt now so maybe a 4 blade of the same pitch?

I dont think same pitch on a 4 blade will help you, bravo 1 start at 22p in 2p increment a bravo 1 22p will turn same rpm than the mirage plus 23p if your prop is a std mirage 23p you will turn the b1 22p arond 4600 WOT.
Revolution 4 prop have a 21 pitch that can be a good test prop
bblade offer prop test program.

I have the same boat but single engine version and with bravo1 4 blade prop i gain a way much better cruise speed and acceleration with same top speed.
Now i want to try a revolution 4 prop i think they are better on top speed than the bravo1 prop.

Adamcoover 08-10-2012 08:33 PM


Originally Posted by Adamcoover (Post 3750386)
I was un aware of loosing top end. She's got plenty of grunt now so maybe a 4 blade of the same pitch?


Originally Posted by supermx96 (Post 3750454)
I dont think same pitch on a 4 blade will help you, bravo 1 start at 22p in 2p increment a bravo 1 22p will turn same rpm than the mirage plus 23p if your prop is a std mirage 23p you will turn the b1 22p arond 4600 WOT.
Revolution 4 prop have a 21 pitch that can be a good test prop
bblade offer prop test program.

I have the same boat but single engine version and with bravo1 4 blade prop i gain a way much better cruise speed and acceleration with same top speed.
Now i want to try a revolution 4 prop i think they are better on top speed than the bravo1 prop.

How do I find bblade??

supermx96 08-10-2012 09:11 PM


Originally Posted by Adamcoover (Post 3751081)
How do I find bblade??

web site: www.bblades.com

phone: 920-295-4435

Adamcoover 08-11-2012 09:31 PM

Thanks


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