[newbie]a rudder of a sailboat having entrance-exit holes?

Discussion in 'Hydrodynamics and Aerodynamics' started by aL27jrcf, May 27, 2025.

  1. aL27jrcf
    Joined: May 2025
    Posts: 2
    Likes: 0, Points: 1
    Location: pnw

    aL27jrcf New Member

    {27’ junkrig, fibreglass and cedar- almost in final stage for expedition. It is equipped with Yamaha t.9.9 exht. Specifics of model of the boat still under investigation due to hazy record keeping of previous owner.}

    Hi, folks thanks in advance. I’ll add more photosin the morning.

    1. So looking at my rudder there’s bit of chip and needing tlc, I have

    • Fiberglasss cloth
    • Bondo
    • Sandpaper
    • Respirator
    Any other strongly recommend tools/ product for this work?


    2.
    The rudder has two holes. It is attached in this post.
    Is that normal/ certain type of style or hell no patch it up real good?

    3. Please do tell me in terms of aerodynamic and design wise if you notice something out of whack!


    Have a great day

    20250526_205639.jpeg 20250526_205650.jpeg


     
  2. Tops
    Joined: Aug 2021
    Posts: 367
    Likes: 106, Points: 43
    Location: Minnesota

    Tops Senior Member

    Pictures from farther away would be more telling at this point.
    It looks like perhaps a trailing edge extension was added.
     
  3. messabout
    Joined: Jan 2006
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    Location: Lakeland Fl USA

    messabout Senior Member

    What Tops said.
    The closeup pic does not tell us enough. The picture suggests that the surface quality of the rudder is not as smooth as would be desirable.
     
  4. aL27jrcf
    Joined: May 2025
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    Location: pnw

    aL27jrcf New Member

    More photos as promised! Just for addicting a little finishing layer is fibreglass cloths necessary?
     

    Attached Files:

  5. Tops
    Joined: Aug 2021
    Posts: 367
    Likes: 106, Points: 43
    Location: Minnesota

    Tops Senior Member

    Looks like some of the trailing edge broke off (assuming wood at this point) and it was brutally repaired.
    Is it possible to get a picture of it hanging on the boat?
    If it were mine to do I'd be looking for an ideal area for the underwater portion of the rudder for the size of boat and go from there.
     
  6. Blueknarr
    Joined: Aug 2017
    Posts: 1,510
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    Location: Colorado

    Blueknarr Senior Member

    If the former owner 's record keeping skills mach his fiberglassing skills. Then you will never identify the boat's model.

    Most or all of that crap should be cut off.

    Provide us with side views of the hull and keel with somedimensions. We can give you a better rudder profile.

    I hate to get ahead of myself.
    But at the least the paint/gelcoat will need to be ground off before fairing compounds will have a chance to stick. I suspect that much of the glass strips will be effectively removed in that process. So new fg is likely.

    Let's get a better shape before grinding on that atrocity.
     
  7. wet feet
    Joined: Nov 2004
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    Location: East Anglia,England

    wet feet Senior Member

    Pure speculation on my part but it looks like a previous owner did a crude alteration to the original rudder.I suspect the original rudder had a fairly blunt trailing edge and it would be useful to know what the construction is as it may be that the trailing edge was made that way to allow for two halves being moulded and a joining flange incorporated on each half.Alternatively,it may be that the builder lacked the patience to try for a finer trailing edge if the rudder is made of a wooden blank that has been glass sheathed.Was the boat designed with a junk rig,or was that a modification that the same owner added?It wouldn't be the first time that a change of rig has led to a loss of balance and instilled a feeling that a change of underwater profile would make everything right.Seeking answers about the design is definitely the right thing to do as there may be other owners out there who could offer helpful suggestions once that aspect becomes known.
     
  8. Rumars
    Joined: Mar 2013
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    Location: Germany

    Rumars Senior Member

    That's most certainly a shallow water modification. Someone cut the rudder flush with the hull and added the missing area back by laminating the horrible extension to the trailing edge.
    You can either restore the original rudder profile, make a new extension using a core for stiffness, or make a completely new rudder with a folding blade.
     
  9. Skip Johnson
    Joined: Feb 2021
    Posts: 162
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    Location: Lake Tenkiller, Ok, usa

    Skip Johnson Senior Member

    I've done some what I thought was quick and dirty crap over the years but I see now that I'm a rank amateur.
     
    skaraborgcraft and Tops like this.

  10. montero
    Joined: Nov 2024
    Posts: 472
    Likes: 59, Points: 28
    Location: Poland

    montero Senior Member

    Archaeologists will find a kind of ancient drive there...
     
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