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1973 Bertram 46 convertible

Discussion in 'Bertram Yacht' started by Alvaro, Jan 18, 2024.

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  1. Alvaro, Jan 18, 2024
    #1
    Alvaro

    Alvaro New Member

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    Hello. I just join this forum.
    Has anyone repowered a 1973 Bertram 46.6 Convertible with Caterpillars 3196 with twin disc gears ??
  2. Capt Ralph, Jan 18, 2024
    #2
    Capt Ralph

    Capt Ralph Senior Member

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    Hard call to make. Some of us still luv the 3196.
    3406 would be my first recommendation.

    Remember, unless your going to change the clutch and ratio, your wanting the same RPM range of operation you have now.
  3. Alvaro, Jan 18, 2024
    #3
    Alvaro

    Alvaro New Member

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    I guess I should have asked before the removal of the Detroits 8v71 T.
    I bought them as a unit. Cat engine and twin disk gears. but they are about a foot and a half longer. Not sure how to proceed.
  4. Capt Ralph, Jan 18, 2024
    #4
    Capt Ralph

    Capt Ralph Senior Member

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    I hope you still have the 8V71s?
    Your going in the wrong direction.
  5. Alvaro, Jan 18, 2024
    #5
    Alvaro

    Alvaro New Member

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    No I gave them away.
  6. Alvaro, Jan 18, 2024
    #6
    Alvaro

    Alvaro New Member

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    I only have two options. Install the cats or sell them and buy something else to replace them.
    The Cats have 0 hours. Complete overhaul. New heads, oil pump , injectors etc.
  7. boatpoor, Jan 18, 2024
    #7
    boatpoor

    boatpoor Active Member

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    Is there even room to get them in place in the engine room without moving a bulkhead and everything that's attached to it?
  8. Alvaro, Jan 18, 2024
    #8
    Alvaro

    Alvaro New Member

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    No. I think it will fit by cutting about 4 inches of the rib between the engine stringers. What I’m concerned about is the shaft to gear alignment. (Coupler) I guess I’ll find out in the next couple of weeks. I was just wandering in anyone had this cat engines on a 46 Bertram.
  9. DOCKMASTER, Jan 19, 2024
    #9
    DOCKMASTER

    DOCKMASTER Senior Member

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    Have you tried making a simple wood mock up of your available space to see how/if they will fit? When I did my repower this is how we confirmed everything and also used the mock up to fab the mounts. I think I showed the mock up in my repower thread a few years ago.
  10. Alvaro, Jan 19, 2024
    #10
    Alvaro

    Alvaro New Member

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    Dockmaster thank you for the advice. I just meet a gentleman with a 46 Bertram re Powered with Cats 3406. Length 84.69 inches. Going to see his boat tomorrow. He said that is a very tight fit but they fit. My 3196 are 73.8 inches. 10 inches shorter.
    He did not have to change the shafts . He did get new props. I’ll take some measurements.
  11. DOCKMASTER, Jan 19, 2024
    #11
    DOCKMASTER

    DOCKMASTER Senior Member

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  12. SplashFl, Jan 21, 2024
    #12
    SplashFl

    SplashFl Active Member

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    Obviously not the same engines but here is a 46.6 that looked beautiful. When shopping I was able to track down the then owner who told me after he sold the new owner moved her from Maryland to Islamorada.

    "To Timing Connie" was complete refit in 2011/ 2012. They stripped the entire vessel including: engine room, tuna tower, electronics, all mechanical systems, all 12 volt wiring, and more. Then every surface was faired and repainted, New tuna tower, all new systems where installed in the engine room (including twin Cummins QSM11's and a 11.5 kw Onan Gen Set, fuel system), New interior, Furuno 3D Electronics, shafts, wheels ,rudders , rewired, Custom Mezzanine and much more. She is a very soft and economical ride at 25 knots.
    https://autodocbox.com/69568163-Road_Side_Assistance/Bertram-mezzanine-two-timing-connie.html
  13. Alvaro, Jan 23, 2024
    #13
    Alvaro

    Alvaro New Member

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    I went to see the boat this past weekend. Those are some big engines. He wasn’t lying when he said a tight fit. I took plenty of measurements and my engines will definitely fit. Hopefully I can get this project done by summer.
  14. Capt Ralph, Jan 23, 2024
    #14
    Capt Ralph

    Capt Ralph Senior Member

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    Look into some down angle clutches.
    Can really save on the overhead room.
  15. Alvaro, Jan 24, 2024
    #15
    Alvaro

    Alvaro New Member

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    Thank you Capt. Ralph. I don’t know what that is. Is it something that you add to the transmission coupler ?
  16. Capt Ralph, Jan 24, 2024
    #16
    Capt Ralph

    Capt Ralph Senior Member

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    A whole different clutch / transmission.
    Instead of the engine installed at an angle, in-line with the propeller shaft as the normal; A down angle clutch / transmission allows the engine front end to sit lower and the clutch out-put shaft/flange is angled down in-line with the propeller shaft.
  17. Alvaro, Jan 24, 2024
    #17
    Alvaro

    Alvaro New Member

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    Oh okay. I see. The thing is that I already have the engine/ twin disk package.
  18. Capt Ralph, Jan 24, 2024
    #18
    Capt Ralph

    Capt Ralph Senior Member

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    When we re-powered from LBCs to Cummins 6TBs in Bert 34/35s, we would of had great headaches without down angle clutches.
    Straight drive TD's make great trading for a down angle TD or ZF clutches.
  19. Alvaro, Jan 24, 2024
    #19
    Alvaro

    Alvaro New Member

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    Let me see if I get lucky and find somewhere /shop that has those and see if they take trade ins.
  20. SplashFl, Jan 24, 2024
    #20
    SplashFl

    SplashFl Active Member

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    When we repowered my previous 38 Bertram we also used angled transmissions and even with them the engines were right up to the salon floor. The only way to check heat exchanger water was via new cut-outs under the salon floor rug. There was an engine broker on St. Rd. 84 back then. I think he was affiliated with RPM Diesel.
    19.jpg
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