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Do you need a stern tube?

Discussion in 'Technical Discussion' started by C4ENG, Aug 10, 2014.

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  1. C4ENG, Aug 10, 2014
    #1
    C4ENG

    C4ENG Senior Member

    Joined:
    May 19, 2006
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    Ft Lauderdale
    This is a picture of a 164ft Trinity stern tube. The stern tube lost its protective epoxy cover inside and might need to be replaced. Some people say that the stern tube is not necessary and can be removed completely.

    Why would the builder then install stern tubes if they are not necessary?

    Could the spinning of the shaft in that tight quadrant create cavitation up against the haul?

    Attached Files:

  2. Capt J, Aug 10, 2014
    #2
    Capt J

    Capt J Senior Member

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    If the builder put it there, it was most likely for additional shaft support and to stabilize the shaft. I would leave it personally unless you have a good naval architect willing to say otherwise. It is possibly it's not getting good water flow to cool it due to the proximity to the hull. However, how many hours are on it? Cutlass bearings only last so long.
  3. captholli, Aug 10, 2014
    #3
    captholli

    captholli Senior Member

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    Let the fun begin!! What does the class surveyor have to say?
    Who would tell you that you don't need what was approved by ABS and built to classification standards by the builder? The guy that runs the travel lift or some idiot captain trying to save himself from the owner/ Management companies **** list?
  4. K1W1, Aug 11, 2014
    #4
    K1W1

    K1W1 Senior Member

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    Hi,

    Get the surveyors opinion.

    If it is badly corroded and corrosion can often look a lot worse than it actually is it is entirely possible that it could be filled with Belzona or similar as it is only the area where the bearings are located that needs to be really true and these could be line bored if so needed.

    It is entirely possible to have a shaft line without a Stern Tube but you will need some other way to secure the shaft bearings to the hull.