Wood boat deck

Discussion in 'Boat Design' started by Travis Grauel, Mar 8, 2020.

  1. Travis Grauel
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    Travis Grauel Junior Member

    A8887DBE-DE1F-4045-AA59-5B4FFCD361B5.jpeg A8887DBE-DE1F-4045-AA59-5B4FFCD361B5.jpeg So I’m building my first boat which I’ve posted about before but it is an 18 foot v bottom boat. I’m having a hard time figuring out how I am going to go about the deck on the Inside of the boat. I want to put a plywood floor but am afraid if water gets through it can’t get out? I’ve drilled holes through every frame to the rear so if water did somehow get through but I wanted different inputs...should I do wood planking deck so I can allow for water to run through underneath the floor? Or should I just ensure I seal it 100% and let’s it run the the Bildge pump hole and out the plug ? I’ll include pics thanks! Also a side note is 2 layers of 7018 biax overkill on this boat?
     

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  2. fallguy
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    fallguy Senior Member

    Water.

    You need to decide how to best manage it.

    If the hull is all wood; and not glassed inside; then water needs to move about and swell the boat up.

    If the hull is glassed inside and out and sealed fully; you can allow water to travel in the bilge. Or you can try to build a dry bilge and keep the water out.

    So, before anyone can really respond; you need to talk more about the hull build details. Two layers of 1708 is not the best plan, imo.

    Also, define the hull finish, paint or gelcoat.
     
  3. gonzo
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    gonzo Senior Member

    Is the green stuff Bondo? If it is you should grind it off.
     
  4. Travis Grauel
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    Travis Grauel Junior Member

    It’s is epoxy fairing compound
     
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  5. Travis Grauel
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    Travis Grauel Junior Member

    I am fiberglassing outside and epoxy and seal underneath floor and epoxy and fillet about floor ...what would you choose for fiberglassing? Also it will be painted outside and above the floor on inside
     
  6. fallguy
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    fallguy Senior Member

    Make sure to not sand the fairing compound too smooth; you want the best bite you can get.

    I am not qualified to spec the glass. For glass advice; you need to provide the engine plan and the framing plan and the plywood used.

    I am qualified to tell you 1708 x2 is not likely the best. It looks like your core is very heavy already and 1708x2 will add too much weight for too little strength gained. 1708 at 1:1 resin in two layers is nearly 7 pounds per square yard. Or like 150 pounds for that boat..outside alone.

    You also need to define the resin plan.
     
  7. Travis Grauel
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    Travis Grauel Junior Member

    i wanted more weight actually because I have a 30 hp motor which I think is overkill for it...the frames are oak 1x3 and it’s 1/2 marine grade Douglas for plywood ....
     
  8. fallguy
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    fallguy Senior Member

    Also, how did you seal the plywood to the frame? If you allow ingress in that seam; I don't like it much. Just an epoxy coating on the bottom will not prevent ingress between the plank and frame.

    I do not profess any expertise on plank on frame / resin hybrids.

    I am capable of seeing potential problems and that is one.

    If you can or did seal that interface; it would change the approach. Or it may be required. Wish I had an answer.

    You need to answer that question for sure. And designing a dry bilge might also be required.
     
  9. fallguy
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    fallguy Senior Member

    The glass plan for the transom and the hull are never typically the same.

    Another consideration to spec glass is typical use. If you were running oyster beds; it would be different than a fishing boat.

    You will gain very little strength from all that glass on the hull. You need to glass the bottom seam and chines with tapes and then some lighter glass over the hull. Probably some light woven fabric would be good. But I am truly not qualified here.
     
  10. Travis Grauel
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    Travis Grauel Junior Member

    Thanks for the reply’s I used waterproof wood glue but didn’t seal where they make contact I planed on using epoxy fillet everywhere a frame meets plywood then multiple coats of epoxy on the inside...what would your approach be??
     
  11. fallguy
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    fallguy Senior Member

    These arrows an picture explain areas of concern. Water gets in here and rots stuff.
    6942A62B-8391-4510-BED2-26EFF51CE2B8.jpeg
     
  12. gonzo
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    gonzo Senior Member

    What do you call "waterproof wood glue"?
     
  13. Travis Grauel
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    Travis Grauel Junior Member

    Titebond level 3.....are you gonna help with my initial post or....
     
  14. Travis Grauel
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    Travis Grauel Junior Member

    10-4
    do you think fillets on all the inside corners where hull meets frame will suffice?
     

  15. fallguy
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    fallguy Senior Member

    One of the reasons I am not a fan of pof is this issue.

    It is very hard to keep these areas from getting water into them. The areas of migration are many and nearly impossible to mitigate. The old wood boats embraced it and they swelled up and stopped leaking, but cycles of drying resulted in rot. Those boats would use limbers and run the water to the bilge pumps.

    I probably would not fillet all those seams. I would probably seal the wood before applying it to the frames, but that ship may have sailed as well.

    Rather than trapping the water, I would probably seal the plywood, but not work hard at sealing the plank interfaces and allow them to dry out offseason. Install a garboard drain and limber the frames. You can use an oscillating tool if you failed to do so already.

    Then build a dry deck and seal the bilge off. Use 4" 1708 tapes at the deck/hull interfaces. Pay special attention to the intersecting frames and epoxy fillet them and tape them well.

    So, you build a dry bilge that can be inspected and allowed to dry out.

    For water on deck; you scupper or build a bilge pump area at the stern. Make sure the pump area is sealed with fillets and 1708 so it can't leak back to the dry bilge. The garboard drain needs to be offset on one side and dump out the transom, or you could build a removeable deck place that is sealed in 4200 to inspect the bilge. I believe you have a center keel, so you need to limber across of each side.
     
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