CV drive-shaft/thrust bearing comments?

Discussion in 'Inboards' started by M&M Ovenden, Jul 30, 2007.

  1. M&M Ovenden
    Joined: Jan 2006
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    M&M Ovenden Senior Member

    Our hull is built, we are now working at the detail components of the boat, getting it ready to sandblast the inside this fall. We are also planning in detail the boats systems of which the motorization.
    Here's our issue and reason of this post. We are debating using a CV drive-shaft and thrust bearing assembly (python drive, aquadrive) or not.
    I never really found the standard installation of engines in sailboat made much sens. An engine mounted on rubber even carefully aligned within tight tolerance doesn't maintain its drive shaft on a descent strait axis, it's all over the place. Adding to the inherent vibration the thrust misaligns the system back and forth and the healing side to side, resulting into unwanted loads and wearing actions.
    On an other side, in some cases adding components and complicating a system can have its cons and some times not make sens either.

    Maybe to guide ideas a few details about the boat could help. It's a heavy displacement 53000 lbs sailboat, 50ft. We are currently planning on powering with a beta marine BV3300-75 hp (we are not big on over powering a sailboat). Du to the hull shape the drive shaft will have a 8 degrees angle (max spec installation angle for the engine is 15 degrees). Space for CV-drive is not an issue.

    We are fans of simplicity but also like doing things right. So is it worth going the extra mile and equipping our sailboats engine system with a CV drive-shaft and thrust bearing? What are others experience with those assemblies? Is there a brand/kind to favor or other manufacturers to consider apart from the major known ones? I tend to consider work boats rather than yachts as good comparison base for sturdy systems, what drive installation do small work boats favor? Ok that might be enough questioning, you probably get the trend.

    Joined: Oct 2002
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    FAST FRED Senior Member

    DO IT, We have a simalar setup and its GREAT!

    Besides never wondering about engine alignment, the ability to REALLY soft mount the engine (exhaust water & fuel need to be as flexible) the reduction in noise and vibration is fantastic.

    Its expensive (aqua drive) but well worth it. Build the engine mounts so you can toss a replacement engine in , and you will never worry about parts or obsolesence.

    If you have the $$$ most controllable pitch props come with a thrust bearing Hundstat (sp?) or similar, saves the cost of some crummy folding prop that is worthless at backing.

  3. brian eiland
    Joined: Jun 2002
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    Location: St Augustine Fl, Thailand

    brian eiland Senior Member

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