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Source for second hand propeller shafts

Discussion in 'Props, Shafts & Seals' started by Trinimax, Mar 29, 2020.

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  1. Trinimax

    Trinimax Senior Member

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    Trinidad and Tobago Yacht club
    Hello all.
    A friend of mine is looking to start a repower project in the future, (going up from GM 1271 TIs to Cat 3412s

    and he is looking at the possibility of purchasing used propeller shafts.

    Does anyone know of any reputable suppliers for used/ second hand propeller shafts in the Florida / east coast of USA area.

    Thanks in advance for your responses.
  2. Pascal

    Pascal Senior Member

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    Personally I wouldn’t. I considered it when I repowered my 53 and went with new. The cost of new shafts is a fraction of the cost of the repower.

    if your friend goes this route make sure he has the shaft magnafluxed near the keys to be sure there are no cracks.
  3. Capt Ralph

    Capt Ralph Senior Member

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    2 1/2" should be behind the 12v71s, Sometimes 3".
    2 1/2 to 3" (pending tune), usually 3" would be behind the 3412.
    Anybody pushing the Detroit TI w/ 2.5" shafts would install a high saftey factor of stainless.
    Almost a damm good poker hand that I could play.

    Have them inspected and stay with the originals if you can.
    I know I feel a bashing coming on for this.
    Let the flailing begin..

    I'd look for a pair of 3406s (as I have) and have the best of both. 800+ HP at half the weight of the 12TIs.
    SAE#1 wheel and keep the same clutch.
  4. Trinimax

    Trinimax Senior Member

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    Hi Capt Ralph, funny enough this friend of mine is doing this repower on 68 bert MY, 58 with a ten foot cockpit. So yes the boat currently has 2.5 inch shafts and he will need to go up to 3 inch shafts. By chance, do you have the shaft length for your prop shafts. The owner couldnt find it in the manual onboard, and it isnt in the manual on the bertram website either.
  5. Capt Ralph

    Capt Ralph Senior Member

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    2-1/2 x 190-5/8" A-22 Double Taper shaft.
    Plus - Minus any changes in clutch installation.

    What tune (HP) will the new engines have?
    I would luv it if you could keep up a re-power thread on this project.

    Old Bertram support available from High Tide Marine in Marathon FL.
    Last edited: Mar 30, 2020
  6. Trinimax

    Trinimax Senior Member

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    Hi Ralph, thanks for the quick response, much appreciated. Yes once things get started I will start a thread and keep you guys updated on the progress.
  7. DOCKMASTER

    DOCKMASTER Senior Member

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    I agree with others. Buying used shafts is not really a place to be trying to save a few bucks given potential risk. In my Repower going from 2.5" shafts to 2.75" AQHS the shafts themselves were actually quite reasonable I thought. Overall they were less than 3% of my cost of equipment. Why take a chance there given the risks?
    Really the bigger question is what is going to be involved in going up to a 3" shaft? Are the shaft logs and struts big enough and can they be line bored to take a 3" shaft or do they have to be replaced? In my case I chose the 2.75" AQ22HS as the safety factor calcs were acceptable to me and I was able to use a thin wall cutlass bearing and handle the larger shafts in my existing struts and shaft log. I'm not familiar with the older Bert's so maybe this is moot? You also don't want to fall into the trap of just looking at HP for your shaft sizing. Are you changing gear ratio and prop diameter/pitch? All has to be factored.
  8. Capt J

    Capt J Senior Member

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    I'm guessing he's going with 3412's because he found a used set. I'd highly consider going with 1000/1150 HP Cat C18's over 3412's......both are great motors, but a good weight savings to be had and could possibly utilize existing shafts with C18's. I wouldn't recommend going with used shafts either......Ask yourself why someone has used shafts to begin with, because a lot of times they came out of a boat that was junked due to condition, OR some repowered but they're going to be old shafts if someone repowered also.
  9. Capt Ralph

    Capt Ralph Senior Member

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    A mechanical 3412 would not need new shafts. The 3412E will need good 3" shafts.
    Yes, the Bert 58 MY struts leave no room for expanding shaft size with out replacement. I don't recall much room to bore to 3" shaft bearings.
    There is an intermittent Strut so 4 new struts. No bearing in the shaft tube. The shaft tube just may fit a 3" shaft.

    The only reason to go with the 3412s is a good deal on them and the original engines are EOL.
    OTOH, If the 12V71 crank is still good, The TD clutches have no issues (never do) the 12V can be built up past the HP of the mechanical 3412.
    Saving a lot of down time, labor and expense.
    With the salon deck up, un-real room to work on the Detroits. Salon cap comes off so anything can be picked near straight up to the dock if needed.
  10. Trinimax

    Trinimax Senior Member

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    Thanks for the responses fellas, after some thought, my friend has decided to pursue new shafts. As Captain J said, yes the owner is going with 3412s at 1250 hp as he found a deal on a used set with gearboxes. New struts will also be in order and hopefully the shaft tube in the hull could accept the larger shaft log.
    Once the project starts, I will start up a thread.