Drive shaft for remote v installation, please advice

Discussion in 'Inboards' started by Magnus W, Feb 7, 2018.

  1. Angélique
    Joined: Feb 2009
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    Location: Belgium ⇄ The Netherlands

    Angélique aka Angel (only by name)

    I'm sorry, on second thoughts you were right in post #6, that is if the torsional damping shaft with it's the CV couplings solves the angle difference with the prefered prop shaft angle as result, so you only need the lower green unit in the picture if the target is to big to solve the desired angle difference with the upper set of CVs alone.


    But take note, where you don't apply CVs, you need a perfect alignment in all directions, otherwise this will give vibrations in the boat, and much extra wear on the not perfectly aligned parts.
    Last edited: Feb 8, 2018
  2. Rumars
    Joined: Mar 2013
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    Location: Germany

    Rumars Senior Member

    That's what I understood. He inclines the transmission to get a different angle on the propshaft, and the resulting angle between motor and transmission can not be solved by a pair of universal joints so he needs another form of CV joint. Now with the new angle proposed he must check again and see wich solution to take:
    1. Incline the motor to be inline with the transmission.
    2. Use a pair of universal joints.
    3. Use some form of true CV joint.
    The only difference to the initial situation is that the driveshaft between motor and transmission is now shorter.

  3. Barry
    Joined: Mar 2002
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    Barry Senior Member

    Design Guidelines for Drive Shaft Installation Angle | Engineers Edge

    this might help plus there are a bunch of sites on driveshaft design
    There will not be any need to have a thrust bearing between the engine and transmission. Only between the v-drive and the prop shaft but
    all Vdrives have this as an inherent part of the design as the out put shaft is meant to be hooked to a prop
    The problem that you will have though is that the drive shaft between the vdrive and engine will need the ability to slide to compensate for the
    slight movement of the drive shaft as the u joint rotates. Plus even more importantly, you will not be able to mate up the flanges on the drive shaft
    to the flanges on the engine/vdrive within thousandths of an inch. So that you will build in a tension element into the shaft. Obviously not compression or you would not be able
    to put the shaft in. With the flex of the boat, you would be imparting high loads to the engine/vdrive flanges.
    I think that some of the marine couplers can accommodate some small length changes
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