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-   -   don't know where to start? (https://www.offshoreonly.com/forums/prop-talk/267216-dont-know-where-start.html)

2manyprojcts 12-15-2011 06:36 AM

don't know where to start?
 
Im doing a project boat and I have never run the boat before so I don't have a clue where to start with a prop.
The boat is a 1990 Profile gt 26 it has a small pad and I am running a 475/500 hp big block with a bravo 1 with a 136 drive it has a Bobs nose cone with a low water pick up on it. Any help would be great.
Thanks Keith

POWERPLAY J 12-15-2011 06:45 AM

24-26P Bravo1 ???

2manyprojcts 12-15-2011 06:52 AM


Originally Posted by POWERPLAY J (Post 3571456)
24-26P Bravo1 ???



Yes its a bravo 1 and its A drive from another boat that I had in the garage.
I never ran the boat and never had one with a pad. would you run a four or a three blade
Thanks Keith

A.O. Razor 12-15-2011 07:08 AM


Originally Posted by POWERPLAY J (Post 3571456)
24-26P Bravo1 ???


Originally Posted by 2manyprojcts (Post 3571461)
Yes its a bravo 1 and its A drive from another boat that I had in the garage.
I never ran the boat and never had one with a pad. would you run a four or a three blade
Thanks Keith

Keith. Powerplay J was talking about the Mercury Bravo1 prop.

It depends on where the power is made. Even if the motor spins "only" 5200 max, a 26" (25") B1 would put it at 80 mph with a 12% slip. I think that number is too high with that power. I would prop for about 73-75 and go from there. Overall, when stuff is new, baseline testing is needed. Either 23" Rev4 or Bravo1 24" if spinning 5200 and up. The Rev4 has an overall better lift than the B1, so that would be my first choice.

2manyprojcts 12-15-2011 07:27 AM


Originally Posted by A.O. Razor (Post 3571468)
Keith. Powerplay J was talking about the Mercury Bravo1 prop.

It depends on where the power is made. Even if the motor spins "only" 5200 max, a 26" (25") B1 would put it at 80 mph with a 12% slip. I think that number is too high with that power. I would prop for about 73-75 and go from there. Overall, when stuff is new, baseline testing is needed. Either 23" Rev4 or Bravo1 24" if spinning 5200 and up. The Rev4 has an overall better lift than the B1, so that would be my first choice.

thanks I dont know the weight of the boat but it seems very light looking at the lay up and in way its built even kinda cheap I hate to say. I have a new transom in it would you consider raising the drive? now would be the time to do it. I hopeing it will be a fun good all around boat its pretty much a 24 x 7 with a foot and a half added only a 6 foot wide transom.

bajabob 12-15-2011 04:39 PM

i agree with A.O. Razor use a smaller prop . i have a 24baja with a 136drive . i use a 24bravo one prop.truning it at 5800 and i have 718hp 540dart motor . prop your boat to the redline on your motor if it is 5200 then make shore you put the prop that make it spin that good luck :drink:

POWERPLAY J 12-15-2011 05:05 PM

Yup what A.O. Razor said. I know there are a lot of variables but I would start with a 24 B1 4 blade. It might spin a bigger prop but I think its a good place to start.

POWERPLAY J 12-15-2011 05:08 PM


Originally Posted by A.O. Razor (Post 3571468)
Keith. Powerplay J was talking about the Mercury Bravo1 prop.

It depends on where the power is made. Even if the motor spins "only" 5200 max, a 26" (25") B1 would put it at 80 mph with a 12% slip. I think that number is too high with that power. I would prop for about 73-75 and go from there. Overall, when stuff is new, baseline testing is needed. Either 23" Rev4 or Bravo1 24" if spinning 5200 and up. The Rev4 has an overall better lift than the B1, so that would be my first choice.

I do not disagree with you one bit but I believe this hull likes the lift from the B1 props.

Griff 12-16-2011 02:11 AM

I would probably start with 24 Bravo 4 blade. It should run about a 70-75mph if the slip is correct.
Being an older boat, the drive might be set pretty deep and it may actually like a Mirage Plus.
The 24 Bravo should get you decent baseline though.

2manyprojcts 12-16-2011 02:15 PM

thank you very much guys Ill give that a try

LicenseToChill 12-17-2011 12:52 AM

I've had great results with Bravo 1 props on several boats. But don't trust the pitch numbers stamped on the props. My 32s performed like 30s. If you go by the number on the prop, my Fountain was seeing 19% slip at wot. I would call Brett or Brad at BBlades. After making many mods to my boat and testing a few props, they're labbing a set of 5 blade Maximus props for me. They're great guys who are extremely knowledgeable.

Griff 12-17-2011 02:05 AM

Always subtract 1" from the stamped pitch on Bravo props to calculate slip. They are stamped on the heavy side.

onesickpantera 12-17-2011 08:56 PM

Considering the size of the boat and a non-stepped hull I would definitely try a Rev4. MUCH better bow lift than a Bravo.


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