Replacing Deck and a framing

Discussion in 'Boat Design' started by Angler2184, Jan 17, 2021.

  1. Angler2184
    Joined: Jan 2021
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    Location: Ocean City

    Angler2184 Junior Member

    I am replacing the back deck on my boat. Just gonna put back 3/4 plywood. Most of the frames are ok, but the 2 longitudinal ones 2x6x 11ft in the forward most compartment. One is split, one is twisted. For the one that is split I plan to sister another Fur 2x6 the full length on both sides and screw,bolt and glue it. I am not sure exactly what to do with the twisted one. The joint where its scarfed into the aft beam at the bulkhead is also twisted. If I sister this one as I do the other will it pull the twist out?The entire 11ft span is not twisted maybe 6ft or so. Can I run a new 2x6 through the bulkhead and sister it a few past the bulkhead, then run it forward and bolt it to the orginal 2x6 after the twist. Also the side to side frames are not attached to the forward and aft ones. What would be the best way to do this? IMG_5761.JPG IMG_5766.JPG
     
  2. kapnD
    Joined: Jan 2003
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    Location: hawaii, usa

    kapnD Senior Member

    The twisted member can have relief cuts to straighten it, and the sister will take the load.
     
  3. Angler2184
    Joined: Jan 2021
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    Location: Ocean City

    Angler2184 Junior Member

    So i could make a number of small cuts down the board where it twists ?
     
  4. kapnD
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    Location: hawaii, usa

    kapnD Senior Member

    Sure, as long as it’s structural function is taken over by the new sister, or you can remove it and replace with a straight piece.
    Why did the old pieces twist and crack?
    Are they adequate for the job they do?
    Would an aluminum or fiberglass C channel be a better replacement?
     
  5. Rumars
    Joined: Mar 2013
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    Rumars Senior Member

    The longitudinal beams are called stringers, and the transverse deckbeams.
    How is the stringer split? Can you simply glue it back together? The twisted one can have the offending portion cut and a new piece scarfed in.
    Sistering adds weight, and with the deck off you have access to do a propper repair.

    P.S. I hope those two new boards lying on the deckbeams are not destined to become part if your boat.
     
  6. Angler2184
    Joined: Jan 2021
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    Location: Ocean City

    Angler2184 Junior Member

    I got a feeling they twisted when removed our engines a few years ago...
     
  7. Angler2184
    Joined: Jan 2021
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    Location: Ocean City

    Angler2184 Junior Member

    The one split is about 3ft long, I’ll grab some better pictures tomorrow. They twisted one is twisted from the original scarf joint which goes through the bulkhead.

    Na those pt boards won’t be used. I was able to get some clear fir.

    I was also thinking about adding some vertical supports in between the bulkheads. I thought the 11ft span of the 2x6 was too much.....any ideas on this ?
     

  8. Angler2184
    Joined: Jan 2021
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    Location: Ocean City

    Angler2184 Junior Member

    Just an update on the progress, we were able to get the one beam twisted back over and sistered both sides. Plan on coating the underside with VE, and screwing it down next week. Then filling seams with unwaxed VE and cabosil, then tabbing the edges with 1708. Then 2 layers of 1708 on the deck, and use VE and glassbubbles to fair the deck. Plan is to use unwaxed VE until we start fairing. When I fill the seams if I have to do some sanding to smooth it out will I be able to grind on the unwaxed VE and cabosil?
     

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