hobie 18 sx rudder repair

Discussion in 'Boatbuilding' started by BWD, Jun 2, 2007.

  1. BWD
    Joined: Aug 2006
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    Location: Virginia, US

    BWD Senior Member

    Hello.
    I have a friend with a hobie 18 sx with broken rudder blades, right at the top. The forward upper corners broke off when boat was dumped in shorebreak....
    I want to help fix these.

    Wondering what adhesive might be compatible with the rudder material. It is a gray-black molded plastic, smooth surface, slightly "foamy" looking interior. No glass or carbon.
    Planning to try epoxy, PU, and cyanoacrylate, but want to fix without cutting entire rudder up for samples....
    If anyone has done this repair, I would be grateful for advice.
    BTW also thinking of mechanically bolting it together with 1/4 SS mach screws into barrel nuts crossdrilled through stock -belt and suspenders.
    Thanks.
    -BWD
     

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  2. alan white
    Joined: Mar 2007
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    Location: maine

    alan white Senior Member

    I know the material by your description. A hard foam within what is probably a roto-molded PE shell.
    Very high stress area (and so it broke there!)
    A replacement from the factory might be the most practical option, though I would imagine they charge enough.
    Very hard to work with PE because it doesn't stick well to epoxy.
    One option would be to make a fiberglass/epoxy shell to fit over maybe 8" of the rudder and bond that with PU adhesive. First I would adhere the broken-off piece by whatever temporary means are available, then grind that area thinner (so that a "jacket" of epoxy/glass will end up the same thickness after lay-up where the attachment to tiller, pivot, etc. are).
    Then wax and cover with hefty-bag plastic, wrap with glass/epoxy, and when cured, remove the shell and re-adhere with polyurethane adhesive.
    Most anything else you do will not take the stress, I think. This should work fine. Might make sense to cut the broken piece off after removing the shell. You could then fill the area around the holes with solid epoxy after drilling your first hole. The remaining holes can be drilled after that filler cures.


    alan
     
  3. BWD
    Joined: Aug 2006
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    Location: Virginia, US

    BWD Senior Member

    So, you make a mold and then use the mold as the skin- interesting!
    Will have to try this.
    My friend does not want to spend the $200-300 for each repalcement blade (needs a new mainsail too....).
    Will post results if it comes to gether. Thank you for the advice.
    BWD

    Edit: I think these rudders are skinned on lexan. May try solvent welding + glass tape overlay in either a Methylene Chloride/lexan soup or Weld-On 45 or 57 matrix, avoid making a mold.
    Try this
    1. bond broken tip back on with epoxy - just joining the core and getting things in position, but the epoxy will also protect the foam vs. solvent.
    2. grind down skin around the repaired joint.
    3. feather in lexan glop in MeChloride.
    4. grind down the new plastic bump.
    5. overlay glass tape in lexan/solvent matrix or adhesive matrix.
     
  4. alan white
    Joined: Mar 2007
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    Location: maine

    alan white Senior Member

    Make it strong! Wow those new blades are expensive! Those things must break all the time. What a business!
    Good luck.

    A.
     

  5. mrvalrico
    Joined: May 2009
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    Location: florida

    mrvalrico New Member

    Hobie Rudder Repair

    Hello,
    I have sucessfully repaired hobie 18 and 16 rudders, let me know if you still are interested in doing this. They are getting hard to find, keep your old ones!
    They are very efficient blades and can be used on other dingys and boats!
    Yup!
    John
     
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