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Port Vibration After New Zincs ?

Discussion in 'Carver Yacht' started by snelltyke11, Aug 11, 2013.

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  1. snelltyke11, Aug 11, 2013
    #1
    snelltyke11

    snelltyke11 New Member

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    Just splashed boat after bottom, zincs.
    Port now vibrates at 1200rpm and above. Ship yard will pull and replace next week. Ever heard of a zinc being out of round? Was it installed wrong? I'll find out soon, going on the sling Tuesday.
  2. Beau, Aug 11, 2013
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    Beau

    Beau Senior Member

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    Sometime they can come loose and slide down the shaft to the prop hub, or strut. Maybe that's it?
  3. Capt Ralph, Aug 11, 2013
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    Capt Ralph

    Capt Ralph Senior Member

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    BEAU has my only thought also. I just can not imagine a shaft zinc inducing a large vibration.
    However, I have witnessed trash on the wheel from the haul slip, sometimes even the wax paper some yards put on the slings to protect the new paint from getting rubbed off at the chines.
    Have you sent a diver in yet?
  4. Capt J, Aug 11, 2013
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    Capt J

    Capt J Senior Member

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    I agree with the other posts. One other thing I've seen and it's a very very rare occurance. If the cutlass bearings are really old, I've seen them swell or shrink after sitting out of the water for a few days and drying out and then getting wet again after launching. But I've only seen this issue once.
  5. snelltyke11, Aug 13, 2013
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    snelltyke11

    snelltyke11 New Member

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    On The Sling Twice Today

    Pulled out, removed zinc and replaced it with another new one...Splashed it again and the vibration was still there. Pulled it out again and told them to take the new zinc off...Got wet again and PRESTO the vibration was gone...no one knows why???
    Left the new zinc on the starboard shaft and a new stern plate...Should keep me covered in fresh water lake?
    I'll pull this winter, tune the props, replace cutlass bearings put the zinc back on and see what happens...

    It's all very strange?
  6. ksbguy, Aug 13, 2013
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    ksbguy

    ksbguy Member

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    Maybe your cutlass bearing is worn and the small additional weight of the zinc is just enough additional swing weight to cause the vibration. Might be possible if you have small diameter shafts...

    As for galvanic corrosion in fresh water, stray current still flows there. I would probably keep an eye on it but you should be okay short term if the running gear is also bonded to the transom zinc.
  7. Capt J, Aug 13, 2013
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    Capt J

    Capt J Senior Member

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    Could be that the shaft is slightly out or round and the zinc makes the out of round even more noticably. Did they dial indicate the shaft? Check cutlass bearing?
  8. ksbguy, Aug 13, 2013
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    ksbguy

    ksbguy Member

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    There you go! Check the shaft for runout, good idea Capt J.
  9. snelltyke11, Aug 13, 2013
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    snelltyke11

    snelltyke11 New Member

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    I Think CAPT J has it...

    I think that's it, port shaft is slight out of round and the new larger and heaver zinc is aggravating the condition. I'll pull in December and finish this project, need a break just spent 5K on the bottom, transom refurbish, underwater LED.
    Other than that the boat is GREAT.
    :)
  10. snelltyke11, Aug 13, 2013
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    snelltyke11

    snelltyke11 New Member

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    By the way cutlass B are good no play and everything looks true. Do you have to tune props that have no damage? 368 hours.
  11. Capt J, Aug 13, 2013
    #11
    Capt J

    Capt J Senior Member

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    Sometimes. You can check them by placing something on the strut to the propellor to measure the depth to each blade and turn them and make sure that it's the same distance, which is a rudamentry way of checking them.
  12. snelltyke11, Aug 13, 2013
    #12
    snelltyke11

    snelltyke11 New Member

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    Gear man did this today, he said if anything the starboard looked off not the port but he was riding with me and said it was for sure coming from the port. Who knows? Cross Vibration? at any thing above 1500rpm the vibration was not noticed, but after we removed the zinc it was gone. Thanks, these things are a process:confused:
  13. snelltyke11, Aug 13, 2013
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    snelltyke11

    snelltyke11 New Member

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    What would cause a turned shaft or need to tune the props if no damage and low hours 360 something
  14. snelltyke11, Aug 13, 2013
    #14
    snelltyke11

    snelltyke11 New Member

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    Are These Zincs Too Close To The Cutlass & Strutt?

    Are they going to stop flow to the cutlass B?
    They put the new ones right where these old ones were...

    Attached Files:

  15. Beau, Aug 13, 2013
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    Beau

    Beau Senior Member

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    Does that mean the shaft is slightly "egged", or slightly bent? Just curious. If the shaft is bent, that will cause more wear on the cutlas.

    As to position, I usually install my zincs closer to the hull. BTW, is that an old zinc pictured?
  16. Capt Ralph, Aug 13, 2013
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    Capt Ralph

    Capt Ralph Senior Member

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    That's a big egg. The cutlass should get plenty of water but I can imagine some turbulence hitting the wheel. Maybe some sound or what could feel like vibration.
    You have to remember, running gear, propellers, shafts and zincs are Not an exact science. It may still take trial and error in these modern times.
  17. snelltyke11, Aug 13, 2013
    #17
    snelltyke11

    snelltyke11 New Member

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    Yes, these are the old zincs, but they put the new ones in the same spot. Shaft is not bent or twisted. I did not get rid of the vibration until we removed the new port zinc today.
    I thought the zincs should be closer to the hull to allow good flow to pass in the cutlass bearing.
    Good folks at my ship yard, maybe I should give another try and have them move the new zincs up shaft closer to the hull.
    What do you guys think?
  18. Beau, Aug 13, 2013
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    Beau

    Beau Senior Member

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    The shaft is "not twisted or bent", but you say the port shaft is "slightly out of round". What does that mean? Those seem to be inconsistent statements?
  19. K1W1, Aug 14, 2013
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    K1W1

    K1W1 Senior Member

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    Does that include the paint which is missing in your photo?