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Thrust bearing question

Discussion in 'Technical Discussion' started by tildes, May 2, 2007.

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  1. tildes, May 2, 2007
    #1
    tildes

    tildes New Member

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    Engines

    Do anybody know if she has the thrust bearing inside the gear box or has an independent thrust bearing?
  2. Yacht News, May 2, 2007
    #2
    Yacht News

    Yacht News YF News Editor

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    Archnav.de, funny how i have never seen these pictures on here yet. Such an extensive collection of Aposie photos, they really do suffice. Thanks.
  3. K1W1, May 3, 2007
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    K1W1

    K1W1 Senior Member

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    Hi,

    Tildes, Welcome to Yacht Forums

    That is an unusual question for a first post at YF?

    The Prop shaft Thrust bearings would be mounted separately to the gearbox and the Crankshaft Bearings would be in the engines themselves
  4. tildes, May 3, 2007
    #4
    tildes

    tildes New Member

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    Thrust bearing

    Hi K1W1,

    It is an unusual question, but I am building a 70 m motoryacht and I am discussing with the noise and vibrations experts this matter and they do not agree between themselves; so, I am looking for information on different forums about similar ships.

    Thanks for your help.
  5. Innomare, May 14, 2007
    #5
    Innomare

    Innomare Senior Member

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    Tildes,

    You can either have the gearboxes take up the thrust (flexible coupling between gearbox and M.E.) or you can have an independent thrust bearing and a flexible coupling between the thrust bearing and the gearbox+main engine.
    The latter is the solution with less noise & vibrations, but also a bit more costly and the drivetrain becomes a bit longer.

    Good luck!

    Bruno
  6. tildes, May 15, 2007
    #6
    tildes

    tildes New Member

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    We have the added problem of a controlable pitch propeller. The solution with the thrust bearing doen't allow us to put the hydraulic power pack on the gear box, because the flexible coupling. We are now studying the use of very soft flexible mountings in the main engine and hard flexible mountings (able to take the thrust) in the gear box.
  7. Innomare, May 15, 2007
    #7
    Innomare

    Innomare Senior Member

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    ... and a flexible coupling between main engine and gearbox I suppose.
    With some gearboxes you can have a PTO that exits on the top. Then it's not in the way of the thrustbearing or flexible coupling. Which gearboxes are you using?

    The solution you propose works as well. It'll be only a few decibels difference with a separate thrust bearing. (you wouldn''t notice the difference, but it all adds up)