Jackshaft pros and cons

Discussion in 'Boat Design' started by Capt Sport, Mar 30, 2007.

  1. Capt Sport
    Joined: Dec 2005
    Posts: 8
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    Location: SoCal, USA

    Capt Sport Junior Member

    I'm interested in jackshaft power for my next boat. And, was wondering if some of the more experienced designers on here could tell me the pros and cons of powering this way.

    It seems to me that a boat with jackshafted power would be much better balanced, ride better and be more efficient. But I'm sure I'm missing something, or more boats would be built this way. It can't just be that outboard boats are cheaper to build.

    Just to give a little background on the boat I have in my head:

    Center console or center pilot house (full walk around)
    24-28' lenght overall
    8'6"-9' beam (dependant on length)
    diesel power

    What I'm looking for is a rough water boat, with extended range (80-100 gallon of fuel). That is as cheap to run as possible. Think of it as some of the Pacific north west boat designs without the great big full width house and cabin. I'm not looking for the fastest boat on the water either, cruse at 20 knots top out at about 30 knots.

    Thanks in advance for you help and input,

  2. TerryKing
    Joined: Feb 2007
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    Location: Topsham, Vermont

    TerryKing On The Water SOON

    JackShaft to ...

    Capt, A jackshaft (typically with universal or CV joints) can connect the engine to a conventional propshaft/shaftlog with thrust bearing, OR a Vee Drive, OR an Outdrive, OR a Jet, OR a Surface Drive. What are you thinking about?
    Joined: Oct 2002
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    Location: Conn in summers , Ortona FL in winter , with big d

    FAST FRED Senior Member

    The best advantages of the drive is,

    the shaft is quite short from the thrust bearing out , so replacement is cheaper.

    And the engine can be on far softer mounts for a smoother quieter ride.

    And of course an engine change is easy as no difficult shaft alignment is needed .

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