Rebuilding a bulkhead

Discussion in 'Fiberglass and Composite Boat Building' started by chowdan, Jan 28, 2019.

  1. chowdan
    Joined: Jul 2008
    Posts: 82
    Likes: 1, Points: 8, Legacy Rep: 10
    Location: Seattle WA

    chowdan 1980 PAC41 Liveaboard

    Hey everyone,

    Been a while since I've posted on here. I've been a liveaboard on a 41ft sailboat since October of 2018. Since we are in winter, I am slowly working through interior projects onboard.

    One of my next projects that I will be working on is going to be repairing a bulkhead that is rotted from the top down due to a companionway combing drain leak along with a port light leak. Due to the leak, the top 1/4 or so of the bulkhead has rotted out.

    I've included a photo of the area where the rot exists. Below that(from what I can tell) has none.

    I was hoping someone could clarify/confirm that I could just cut a new piece of marine ply to the proper shape and tab it in like you normally would and just do a laminate across both sides of the joints?

    Would this be sufficient enough in terms of strength for any sort of hull flex/movement that may occur?
     

    Attached Files:

  2. rwatson
    Joined: Aug 2007
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    Location: Tasmania,Australia

    rwatson Senior Member

    It sounds fine in theory without having a look. If you want to be ultra sure, you could do some puzzle joints, where the joins with the good plywood have little dovetail "keys" that lock in the new ply, before glassing.
    I have attached a really complex photo of such a joint, but you would not need anything as tricky. A few "dovetail" tabs would be good.
    puzzle_open.jpg
     
  3. fallguy
    Joined: Dec 2016
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    Location: usa

    fallguy Senior Member

    Assuming the ply is 3/4", another option would be an 8:1 or better scarf and thixo or 6" at 3/4". No small task for that spot, but an oscillating tool and a good 1/4 sheet sander would probably work.

    Or sharp chisels and a good chiseler. The joint does not need to be tight as it needs glue. Then wet it with ready resin to avoid a dry joint and add the thickened.

    All the scarf or puzzle joints do is increase bonding surfaces here.
     
  4. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    Epoxy is really good at filling gaps. The scarf can be done with a small grinder. Otherwise, the easy way is a Payson scarf.
     
  5. chowdan
    Joined: Jul 2008
    Posts: 82
    Likes: 1, Points: 8, Legacy Rep: 10
    Location: Seattle WA

    chowdan 1980 PAC41 Liveaboard

    Much appreciated everyone for the ideas/comments.

    I was thinking of doing a scarf above the door and inside the hanging locker, but then started to think about the giant PITA it's going to be actually creating the scarf. Maybe it wont be once I actually pull the trim and look deeper at the design.

    That being said, I totally didn't think about doing a dovetail. That would be quite easy to do, and I could easily integrate a Payson scarf(just learned about this, so thank you gonzo). If i were to do the payson scarf, a couple clamps would be all I need to put the pressure on it the exterior board, and wouldn't be in the way(considering I live aboard).

    The biggest task as always is going to be tearing it all apart as we are full time liveaboards and having to work a normal job will cause it to be a bit of a PITA while dealing with it.
     
  6. redreuben
    Joined: Jan 2009
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    Location: Beaconsfield Western Australia

    redreuben redreuben

    If this bulkhead is anywhere near the mast base or chainplates or other load bearing rigging I would strongly suggest you unload the rig before you start.
     
  7. chowdan
    Joined: Jul 2008
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    Location: Seattle WA

    chowdan 1980 PAC41 Liveaboard

    Thanks, this is not anywhere the rig. This is the bulkhead just aft of the companion way(nearly inline with it). Not structural at all.
     

  8. fallguy
    Joined: Dec 2016
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    Location: usa

    fallguy Senior Member

    not to be a nit, but it is a structural bulkhead; just not related to the rig
     
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