Glassing Stern Tube In Perfectly

Discussion in 'Boat Design' started by helluvaboater, May 12, 2016.

  1. helluvaboater
    Joined: Jul 2015
    Posts: 50
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    Location: Maui

    helluvaboater Junior Member

    I am installing a 3" fiberglass stern tube and 1.75" prop shaft in a 27 foot boat.

    I plan to put the shaft where it needs to go and make some type of guide to hold the fiberglass stern tube in perfect alignment so that I can fiberglass it in place.

    I would like to make something like this:


    The only problem... I do not have access to a machine shop to make the pieces.

    I was thinking of cutting two 1-inch pieces of the fiberglass tubing I will be using for the stern tube, coating them with PVA and then filling them with resin. That would give me the outer shape I would need. Then, I could drill a 1.75" hole directly in the center of the part with a drill press.

    Would this be accurate enough?

    I am using Tides Marine dripless shaft seals which apparently can tolerate some imperfections in the alignment. Is this something a machine shop HAS to do or is it something I can do at my house with some basic tools. Are we talking g
  2. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    Once the shaft is aligned to the final position, you can align and center the tube with wooden wedges between the shaft and the tube. Fiberglass the tube in position, then take the wedges off.
  3. steve123
    Joined: Dec 2014
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    Location: China

    steve123 Junior Member

    Cut two plywood rings with a hole saw same diameter as inside of sterntube, then 1.75" hole in center. Cut in half then locate either end of sterntube when shaft in place, these will hold tube central. See sketch

    Attached Files:

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    Joined: Oct 2002
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    FAST FRED Senior Member

    Once you get it lined up perfectly I would use chockfast .

    A couple of ply or cardboard pieces can form a well which it can be poured .

    When it hardens , no problem discarding the cardboard.

    This is used to line up engine beds on thousands of HP ships , so it will have no problem with your shaft bearing.

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