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-   -   A few stir-the-pot questions (https://www.offshoreonly.com/forums/sutphen/237215-few-stir-pot-questions.html)

dba900 08-19-2010 12:50 PM

A few stir-the-pot questions
 
Well, it looks like the motors will have to come out of that OP we bought. One of the oil pans is rotten and we'll probably take a good look around while we've got 'em out. With that in mind, a few questions for the collective:

1. Bravo conversions: Has anyone done one? I know what's involved. Obviously, you'd gain more space in the engine compartment and you'd lighten up the back of the boat a bit. You could also optimize the X-dimension, which would be nice. Are you going to gain much speed from this swap? TRS drives are more rugged than Bravos, which is a consideration.

2. I gather it takes about 500 hp per side to get an OP to 80? How about 85?

rchevelle71 08-19-2010 01:22 PM

You may lighten up the back of the boat, but you will also change Center of Gravity.

dba900 08-19-2010 01:23 PM

Hmm, good point. Too bad there aren't any cheap Arnesons floating around...

phragle 08-19-2010 01:35 PM


Originally Posted by rchevelle71 (Post 3186263)
You may lighten up the back of the boat, but you will also chenge Center of Gravity.

I have heard this a lot when talking about a TRS bravo swap, but my mind also thinks that while removing weight you are also shoving the heaviest peice, the motor back. had any one ever actually figured out the real difference?

wstultz 08-19-2010 01:51 PM

You may check into extension boxes. I think Stelling makes an extension box with a TRS bolt pattern on the transom side and a bravo bolt pattern on the drive side. It would save some fiberglass work plus you could leave the engines where they are and run shafts or scoot them back since you are pushing the drives back. It may equal out your Cof G. Just a thought.

dba900 08-19-2010 02:17 PM

It sounds like it might not be worth the work to do all of this when the drives and transmissions work fine as-is. I suppose I could always call the factory. It might be simpler to just build/buy bigger power.

phragle 08-19-2010 02:37 PM


Originally Posted by wstultz (Post 3186287)
You may check into extension boxes. I think Stelling makes an extension box with a TRS bolt pattern on the transom side and a bravo bolt pattern on the drive side. It would save some fiberglass work plus you could leave the engines where they are and run shafts or scoot them back since you are pushing the drives back. It may equal out your Cof G. Just a thought.

Merc makes a plate that bolts on for a volvo to bravo conversion that can also be used for trs to bravo conversions, but I would still want to just redo the transom and have some flexibility on drive height.

OL40SVX 08-19-2010 03:49 PM

Go on to Boatfreaks and look for Sutphen 30. He runs Bravos on his and it runs well.

dba900 08-20-2010 09:50 AM

Would 550 hp be pushing it on a set of standard Bravos?

wstultz 08-20-2010 10:59 AM


Originally Posted by dba900 (Post 3186859)
Would 550 hp be pushing it on a set of standard Bravos?

I've seen Bravos take a lot more than that but it is all in how you treat it. If you plane like you're in an inboard ski boat, yes, you would destroy them quick.


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