Partially rotted wood transom repair or replace

Discussion in 'Boat Design' started by the brain, Mar 10, 2025.

  1. the brain
    Joined: Sep 2016
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    the brain Senior Member

    heres all the Rot areas,would prefer to repair an procrastinate replacement

    1. all of perimeter couple inches inward except for under engine pod.
    all the Rot areas.jpg
    Remember I had to reduce the thickness so the plywood would fit inside the flange, then just didn’t seal so this cut wood was exposed to moisture. Rot started at the ½” regular wood then spread to the marine. deterated around perimeter.jpg maybe I can drill small holes all around the perimitor an inject the penetrating epoxy? then extend the flange on both sides? extend the flange.jpg

    the original flange is just rivitoed to freeboard the bolted w/ 1/4" x2.25" stainless bolts I could add about 8" of flange then use 1/4" X3" stainless bolts.

    2.at each corner of splashwell what I did was cut stripes of orginal aluminim an bend into a bottom part of splaswell then cover w/ 5200 then fabbed some aluminin.

    Water intruded at the corners. Only rotted in corners of splashwell.jpg
    ENGINE  MOUNTED rigged.jpg
    This splashwell rot which is mainly the ½” of regular plywood outward.

    I’m considering drilling w/ a 3/8”X 18” wood bite outward to remove as much rot as I can reach.

    Then pour liquid transom Arjay 6011-Ceramic Pourable Compound Transom Putty-Cruise.

    Mite be a good idea to even drill out the not rotted ½” regular wood, would probably make the pour easier. Kindof like pouring inside the transom.

    inbetween the whats still good marine plywood. Then seal the wood w/ epoxy an seal the splashweel better I was actuely planning to have the splashwell welded but was concerned bc I used very thin 1/16” aluminum.orginal aluminum is 1/8”.

    Thanks for advising.
     
  2. fallguy
    Joined: Dec 2016
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    fallguy Boat Builder

    You are doing all the work. My standard rule is when I do the work, I use the best materials. Remove all the plywood and put back Coosa BW 26.
     
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  3. the brain
    Joined: Sep 2016
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    the brain Senior Member

    yes I do all the work, except the welding where I fab up stuff an hire welder. yes I'm leaning toward the coosa 26 for transom replacment and the new splashwell.which will be 7.5" higher. new transom 7 taller.jpg

    I just found out the coosa needs to be sealed w/ fiberglass. not sure if that applies to my vessel since I have a transom cap that covers the transom.

    when I fab up a coosa splashwell will the fiberglass matting stick to the aluminum? thanks
     
  4. ondarvr
    Joined: Dec 2005
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    ondarvr Senior Member

    Pentrating epoxy is pretty much worthless, so skip it.

    Fix it right and move on.
     
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  5. fallguy
    Joined: Dec 2016
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    fallguy Boat Builder

    I don’t believe that is accurate. Maybe you could seal the coosa with epoxy. I’ve never mated aluminum with coosa so I don’t want to say. I thought the plywood in an aluminum boat only provided rigidity. Is it bonded? Why would coosa require bonding? Anything that sticks to ply will stick to coosa.
     
  6. montero
    Joined: Nov 2024
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    Location: Poland

    montero Senior Member

    From what I see Starcrafts are nice but high maintenance boats , re-riveting , rivets sealing . Transom isn't really strong mechanically connected to the freeboards and bottom . Most load is transferred via kneebrace and bottom stringers . Need outer bracket for outboard.
    Maybe best way is weld one piece kneebrace-engine bracket with welded in aluminium transom . Where single sheet of transom meet the collar, and on the top of transom square profiles need to be welded in .
    Sheet thickness 6mm . The whole thing should be installed using sealant and screws like the original transom and kneebrace.
     
  7. the brain
    Joined: Sep 2016
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    the brain Senior Member

    no the transom sits inside side an bottom flanges it just slide in then held in place w/ 1/4"x 2" aluminum though hull bolts the lift hooks also hold in. so yes in your assumption only provided rigidity.
     

  8. the brain
    Joined: Sep 2016
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    the brain Senior Member

    not sure what high maintaince on hull is when I purchased 11 years ago she had 3 viitos that poped out the seller showed them to me easy fix w/ slitely larger blind rivot an g/flex. haven't had any vitos fall out. this vessel was an in board so it never had a knee brace. there's like three rows of rivto at freeboard an transom skin seams standard comparing to other simiail vessels.
    the Starcraft is an economcal vessel not top of the line. the older Starcafts IMO are better than new aluminum pilot house types including Starcraft bc of the thin aluminum used most 22' hulls nowadays don't weight 1900LB they weight twice that BC the thin aluminum can't be welded. here's what I desire but mite be way more fabbing that I can handle bc I don't know how it is structurally made.I believe this is acutely a hull extension. talk me into fabbing this, if I only knew how there made the sides look easy. who knows this whole thing mite be easier than my new planned pod.
    nice pod.jpg
    home made version View attachment 201459 View attachment 201459 pod hull extension.jpg 1f746ab3af30a07314d41b04be77d456.jpg
    I bet the transom is build like this under the skin
    View attachment 201459
     
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