Reinforcing old ribs

Discussion in 'Fiberglass and Composite Boat Building' started by amSteve, Apr 30, 2018.

  1. amSteve
    Joined: Jan 2017
    Posts: 5
    Likes: 0, Points: 1, Legacy Rep: 10
    Location: wisconsin

    amSteve Junior Member

    I'm working on an older houseboat that has a slight list to port - a list that can really only be explained by soft (or broken) ribs on one side. Last season i corrected the list by placing 400 pounds of ballast on the starboard - there's no way there's a 400 pound difference starboard to port so the list must be due to how water is pressuring against the hull.

    It would make sense, the boat has been lifted in and out of the water each of it's 40 year life - not lifted by slings which would have been easier on the hull but by pads on a trailer. Stands to reason the glass at the bow has gotten a bit soft.

    So I'd like to take a swing at reinforcing the area. I'm thinking it shouldn't be too difficult to apply a new layer of glass over the front 2 or 3 existing ribs. I'm reasoning that i should rough up the existing surface and drape new glass over the top of the rib - over lapping 3-4 inches to either side of the rib.

    Or both drape over the rib as well as the area between them (for the first 4 feet or so of the bow).

    Or should i consider doing the work on the exterior -- to place a few square feet of 'patch' to the outside of the hull instead of reinforcing the ribs themselves?

    I'm hoping for guidance on what weight glass to use - epoxy resin seems to be the choice (for sake of strength) - is brand of epoxy worth paying attention to?
     
  2. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    If this is a plank on frame hull, the repairs you propose won't work. In fact they will create more problems than you already have. A boat listing is not caused by broken frames (ribs), but because of weight distribution. However, you mention there is glass at the bow. Can you show some close-up photos of what the boat looks like?
     
  3. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Agreed, we need to see the boat, which I suspect is actually a GRP, not wooden. Hull distortion that can cause a serious list, would be very obvious. It sounds like you have a leak (assuming a 'glass boat, the Gibson 36?) and it's filling an isolated compartment, maybe between an outboard stringer and the rest of the under sole structure. This isn't all that uncommon and suggests you take a very good look at the hull when it's out of the water. I'll bet it's an old thru hull that has lost its bedding and is weeping slowly but surely into an out of sight area, below the sole. Of course, it could be a crack, hole, previous repair, etc., but thru hulls are a common source for leaks. Drag the boat out and have a very close look at the underwater surfaces, particularly anything that protrudes through it.
     

  4. amSteve
    Joined: Jan 2017
    Posts: 5
    Likes: 0, Points: 1, Legacy Rep: 10
    Location: wisconsin

    amSteve Junior Member

    Yeah - Gibson 36 from the early 70s. I'd drilled out a thru hull for a depth finder and found about 1/4 fiberglass - no wood. I sealed the only old thru hull a couple years ago. Water trapped in a compartment was my first thought too but last season when i corrected the list i watched for water coming back to the bilge and saw none.

    I get the possibility isolated compartments but I've had access to virtually every 'between the ribs cavities' (including literally all of them in the stern half of the cabin when we laid in new flooring) and have never encountered an intermediate stringer. But based on your feedback I suppose I'll poke around the couple in the midships that I haven't yet probed -- and will dig up some pictures.
     
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