33 repower and running gear?

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SeaDrive
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33 repower and running gear?

Post by SeaDrive »

For those of you that have re-powered with 300/330 Cummins or similar Yanmar or Cats from gas did you have to upgrade your running gear (shafts, struts etc)? Just curious thanks Jon
Boatless on Cape Cod but looking.
butch
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Re: 33 repower and running gear?

Post by butch »

Over 15 years ago went from gas to 3116 cats 350hp. ( ZF 1 to 1.5 )On a 35 Bertram upgraded from 1 3/8 to 1 1/5 shafts same struts with a cut down cut-less bearing. My friend did a 33 with 3116 cats 300 hp.from gas and believe the boat already had 1 1/2 shafts I know he did not change them. With a different gear ratio you may need to upgrade the size. Both boats have 3000 + hours with out issue. I know of several 35 conversions that took the same route as myself. Good luck with your reporter
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Re: 33 repower and running gear?

Post by Admin »

SeaDrive wrote: Fri May 08, 2020 4:47 pm For those of you that have re-powered with 300/330 Cummins or similar Yanmar or Cats from gas did you have to upgrade your running gear (shafts, struts etc)? Just curious thanks Jon
I've not done it myself, but in seeing the posts from others that have, pretty sure you have to swap out the majority of your running gear. I am sure one the guys that have will be along in short order to tell you exactly what to expect.
David Sumich
1986 SF - 33 Megabites
Huntington Harbour, CA
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dougl33
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Re: 33 repower and running gear?

Post by dougl33 »

I had to change my props, but I kept my inch and 3/8's shaft. As long as you keep the distance from the back of the strut to the front of the prop small you'll be fine with inch and 3/8's with the 300-330hp Cummins.

I re-powered back in 2007 with zero issues.
Regards, Doug L.
1986 33 Bertram FBC Cummins 6BTA's Queen Elizabeth
Marblehead, MA
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SeaDrive
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Re: 33 repower and running gear?

Post by SeaDrive »

Thanks for info everyone. I'm not repowering, those days are over. If I get another boat it will have all that done already. I was just curious what people had done.
Boatless on Cape Cod but looking.
SeaDrive
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Re: 33 repower and running gear?

Post by SeaDrive »

butch wrote: Sat May 09, 2020 6:24 am Over 15 years ago went from gas to 3116 cats 350hp. ( ZF 1 to 1.5 )On a 35 Bertram upgraded from 1 3/8 to 1 1/5 shafts same struts with a cut down cut-less bearing. My friend did a 33 with 3116 cats 300 hp.from gas and believe the boat already had 1 1/2 shafts I know he did not change them. With a different gear ratio you may need to upgrade the size. Both boats have 3000 + hours with out issue. I know of several 35 conversions that took the same route as myself. Good luck with your reporter
Butch
What do you see for speed and fuel burn on the 35 with those 350's?
Boatless on Cape Cod but looking.
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Re: 33 repower and running gear?

Post by butch »

Sea drive. About 24 / 25 knots at 2400rpms. ( 400 off the pins) and clean bottom. and about 25 gals a hour with the gen set running.
Beerman
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Re: 33 repower and running gear?

Post by Beerman »

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