New guy needs help with Bravo drive issue

[rkarran]

Hi all, I just discovered this forum and am looking for some guidance from the Bravo experts.

My 2 partners and I are in the middle phases of restoring a 24-0 1974 CC Blackfin. The boat had been modified by a previous owner removing the original gas motor/running gear and replacing it with a 300hp Yanmar 6LP Diesel motor coupled to a Bravo III outdrive via a jackshaft from the centrally located engine under the deck to the outdrive. It is turning a 30" stainless duo-prop and the boat does SCOOT very efficiently!!

Anyway, shortly after purchase and some subsequent sea-trialing, we decided she was a "keeper". We stripped the boat COMPLETELY to do a (almost) total restoration. We decided not to take the cap off.

We're now about ready to reinstall everything, and have recently received some advice telling us the Bravo III is not strong enough for the 300hp diesel......that we will break outdrive shafts.....I assume he meant input shafts, but it really doesn't matter, as I don't want it to break ANY shafts. I do know that the previous owner DID break and replace an outdrive shaft! We were told that we really need the "stronger" XR outdrive.

Is this correct, or is it BS?
If true, I have some more questions........
Many thanks for your time and input.

 

[Bondo]

Re: New guy needs help with Bravo drive issue

and have recently received some advice telling us the Bravo III is not strong enough for the 300hp diesel......

Ayuh,... Bullship,...
It'll take 400hp,... Gas or Diesel...
Usually when Shafts are twisted or broken, it's from re-entry after a high speed wave launch...
Other shaft failures can be other abuses, or improper set up,+ alignments...

Btw,.... Welcome Aboard...

 

[zbnutcase]

Re: New guy needs help with Bravo drive issue

And lets not forget that some boaters can break a crowbar in a sandbox-thats why there's food on my table...'nutcase

 

[jtybt]

Re: New guy needs help with Bravo drive issue

What do you mean by 30" prop?

What gear ratio?

You got pix of your boat and engine lay-out? I got a Yanmar bell housing/coupler conversion to bravo drive laying around waiting for a boat to put it in.

 

[rkarran]

Re: New guy needs help with Bravo drive issue

I'm VERY glad to hear the Bravo III should handle this motor!! Thanks.

The 30" props I refer to is the pitch. 1 revolution = 30" thrust (theoretical), I believe.

I'll attach a pic where you can see the engine bed and the drive shaft area, with the outdrive removed. Understand that this HUGE engine is crammed in under the (modified) center console and connects to the outdrive with an approx 5 or 6 foot carbon fiber wrapped(?) truck drive shaft that's probably 5" or 6" in diameter, with universal joints on each end. The after end is also supported by a pillow block before attachment to the outdrive. Of course no transmission is required on the engine, since all that is in the outdrive. It's a pretty sweet set-up.

As in the pic, both engine and outdrive are not currently in the boat, so if there's something on those you want a picture of, let me know.

 

[Bondo]

Re: New guy needs help with Bravo drive issue

Ayuh,.... as with aft mounted motors, Alignment is Crucial,....
Get it Right,+ You'll be fine...