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Prop shaft alignment

Discussion in 'Props, Shafts & Seals' started by HKT Horizon, Oct 13, 2007.

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  1. HKT Horizon

    HKT Horizon New Member

    Jun 8, 2006
    Phuket, Thailand
    Hi All,

    I have a 53 feet motoryacht 2 years old now. I'm just wondering if it's necessary to remove and re-align the prop shafts every time during my annual haul out for maintenance. I've noticed slightly more vibration now from when she was new. Do you all think it's a prop or shaft issue? Thanks for your input. Cheers.
  2. Loren Schweizer

    Loren Schweizer YF Associate Writer

    Apr 20, 2004
    Coral Gables/Ft. Laud., FL
    Hi HKT Horizon:

    Perhaps the quickest thing to do is to break the coupling apart from the shaft and, with a feeler gauge, check the faces for angle & out-of-round (runout).
    Do this with the boat in the water.

    You can put a dial indicator on the prop shaft itself (when out of the water) to check runout--six or seven thousandths are OK; more, and you'd better pull the shaft and have the machine shop straighten her out. While I'm not picking on Far Eastern builds, it is not uncommon to find this on them.

    Worst case--the struts are misaligned and then they'll need major surgery if a targeting--laser or wire-- deems this necessary. I had to do this on more than one new DeFever from the factory.