Tabbing shelving to the hull?

Discussion in 'Boatbuilding' started by chowdan, Feb 27, 2022.

  1. chowdan
    Joined: Jul 2008
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    Location: Seattle WA

    chowdan 1980 PAC41 Liveaboard

    Over the years i've slowly been ripping out sections of cabinetry and replacing the bare plywood with new plywood thats painted and/or epoxy coated.

    One thing i've noticed is that everything is tabbed into the hull. I can see why back in 1980 when the baot was built, they tabbed it thinking that it's secured fully and will not move, however, for things like shelving or settee tops, it doesn't fully make sense why you'd tab it in place. The hull sweats, water flows down behind the hull ceiling then sits ontop of this tabbing and is "trapped" in place, causing the wood to rot out over time, or anything on the shelf get wet and gross.

    I've been just screwing/thickened epoxy the pieces in place on the things like the settee top, allowing a small gap to be present where the hull is which means moisture can flow down to the bilge where it belongs.

    Is this wrong? Should i be tabbing the back of the pieces into the hull?
  2. missinginaction
    Joined: Aug 2007
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    Location: New York

    missinginaction Senior Member

    I don't think you're wrong at all. When I pulled my 1973 Silverton apart (before putting it all back together) I noticed that none of the interior bulkheads were tabbed to the inside of the topsides. I hope that makes sense to you. The cabin sole was tabbed in but that was the only part of the cabin that was. Even the transverse bulkheads that support the cabin sole were not bonded to the topsides. Sure, the transverse bulkheads were tied securely to the stringers and were bonded to the inside bottom of the hull but there was about an inch of clearance where they met the topsides at the chines. It was clear to me, looking at the build that this was deliberate and not some kind of oversight. I'm not a marine architect, but I thought about it and decided that by not tying the cabin interior to the topsides an allowance was made for allowing the hull to flex somewhat when necessary.

    When I did the cabinetry I secured it to the cabin sole by gluing and screwing with cleats added for reinforcement.

    I replicated Luhr's/Silverton's design when I replaced all of these parts as part of the restoration. The boat's been in service for 8 years and I've never had a problem.
  3. fallguy
    Joined: Dec 2016
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    fallguy Senior Member


    sometimes shelving is structural
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  4. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    The tabbing was done 42 years ago. I think that is a testimony to a design that is pretty good. If water collects on the edge against the hull, a couple of drain holes will keep it dry.
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  5. chowdan
    Joined: Jul 2008
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    Location: Seattle WA

    chowdan 1980 PAC41 Liveaboard

    Hrm this is a good point. Something i should think closer about. Wont be hard at all to add a strip of tabbing and some holes for things to flow through into the bilge.
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