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Thread: Sheathing with solid lumber

  1. #1
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    Default Sheathing with solid lumber

    I have been considering using solid lumber instead of ply to help sheath the bottom of my next build. Previously, I have been using two layers of 6mm ply covered by glass and epoxy. By orienting the sheathing along ruling lines (developable), I think I could use 12mm solid lumber. At my local lumber yard, I can get red oak, poplar, and maple in 1/2" thickness. Given that any of them would be covered by glass and epoxy, are any of these three three woods to be preferred or to be discouraged from use?

  2. #2
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    Quote Originally Posted by W Grabow View Post
    I have been considering using solid lumber instead of ply to help sheath the bottom of my next build. Previously, I have been using two layers of 6mm ply covered by glass and epoxy. By orienting the sheathing along ruling lines (developable), I think I could use 12mm solid lumber. At my local lumber yard, I can get red oak, poplar, and maple in 1/2" thickness. Given that any of them would be covered by glass and epoxy, are any of these three three woods to be preferred or to be discouraged from use?
    Completely different building method called planking. Spiling, method used for matching planks to the curvature of the boat and other planks, is not hard to learn.

    the woods you quoted above would be trouble even if encapsulated in epoxy on both sudes. Red and white Cedar seem to be the most desired choice,
    Denise, Bristol PA, Oday30, Anchor Yacht Club, On tidal Delaware River. my current project; http://forum.woodenboat.com/showthre...0-Ducker-Resto

  3. #3
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    Default Re: Sheathing with solid lumber

    What is the next build?
    Answers change with different vessels.

  4. #4
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    Default Re: Sheathing with solid lumber

    I am really only asking about the desirability of the three woods mentioned, and I realize that they aren't traditional choices, but with an overlay of glass and epoxy (on a trailered hull) I have seen other choices mentioned as acceptable. This would be my 9th build, and I have used planking previously.

  5. #5
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    You asked, you will get answers, they may not be what you want to hear/read. Those woods of your choice are also more expensive, Red Oak is a terrible choice for anything outdoors it sucks up water like a sponge.
    Denise, Bristol PA, Oday30, Anchor Yacht Club, On tidal Delaware River. my current project; http://forum.woodenboat.com/showthre...0-Ducker-Resto

  6. #6
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    Default Re: Sheathing with solid lumber

    There is a reason that wooden boats covered with epoxy/fiberglass are normally built with thin layers of wood (cold molding, plywood, cedar strip/fiberglass, etc.). The reason is that the fiberglass skins are not strong enough to completely prevent dimensional changes of thicker woods due to ambient conditions. Just a 1% change in plank length due to temperature (1" in a 100" length) is enough to rupture the fiberglass because it doesn't stretch well at all. Construction using thin layers of wood is much more dimensionally stable and far more likely to work and last.

    The woods you mention are rot-prone and not good choices for most boat building. Epoxy fiberglass coating doesn't automatically fix that. Considering the labor involved and the cost of resin, fiberglass and other materials, they would not be a very smart choice. When the time eventually comes to sell the boat (which happens) anybody who knows wooden boats will avoid those woods and your boat like the plague.

  7. #7
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    Default Re: Sheathing with solid lumber

    Thanks, Todd. But, as another alternative, I could rip 12mm marine plywood into planks and do the same thing with better dimensional stability. I understand that okoume is rot-prone, yet it is routinely used for sheathing hulls.

  8. #8
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    Default Re: Sheathing with solid lumber

    The only thing that Rots faster than red oak is maple, and the only thing that rots faster than maple is poplar.

  9. #9
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    Default Re: Sheathing with solid lumber

    I think Robb White advocated building boats of poplar, but I'm not sure it is the same stuff as in the lumberyard.
    Strip and glass might last well if it doesn't let any water into the core. Many balsa core boats lasted a long time, though the decks are noted for rot after years.

  10. #10
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    Quote Originally Posted by W Grabow View Post
    Thanks, Todd. But, as another alternative, I could rip 12mm marine plywood into planks and do the same thing with better dimensional stability. I understand that okoume is rot-prone, yet it is routinely used for sheathing hulls.
    Glued lapstrake ply is a wonderful way to build boats.
    Denise, Bristol PA, Oday30, Anchor Yacht Club, On tidal Delaware River. my current project; http://forum.woodenboat.com/showthre...0-Ducker-Resto

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    Default Re: Sheathing with solid lumber

    Quote Originally Posted by nedL View Post
    The only thing that Rots faster than red oak is maple, and the only thing that rots faster than maple is poplar.
    Yes, but there are lots of different poplars and the only one available in most lumberyards is yellow poplar and it is really a magnolia. http://www.wood-database.com/wood-ar...en-whats-what/
    Rob white seemed to do well enough with yellow poplar. I suspect that there may be regional differences in rot resistance. Some trees are known to vary regionally. It is also possible that Rob took very good care of his boats.
    Management is the art of counting beans. Leadership is the art of making every being count. --Joe Finch

  12. #12
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    Default Re: Sheathing with solid lumber

    Robb White had some distinctive building methods. He did plank with poplar but his planks were extremely thin - maybe 3/16”. He made the planks, then before putting them on the boat he sheathed them on both sides with very thin fiberglass sheathing. 4 oz fabric. His boats were remarkably light and extremely strong.

  13. #13
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    Default Re: Sheathing with solid lumber

    Don't forget folks there is also balsa wood available for encapsulation! It even rots faster than poplar! Note that, I have some property for sale that is forested with a stand of amber snake oil trees! You might find that to be of interest as a boat building material as the snake oil warrants to offer rot protection prior to application. It also cures pips, wens, piles and pellagra and missplaced affections. It will polish the piano and cure the cat! It also is bonded to insure it not to erode, keyrode or implode other than within your line of credit.
    Bird
    Last edited by Jay Greer; 07-09-2018 at 01:26 PM.

  14. #14
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    Default Re: Sheathing with solid lumber

    Where are these boats sheathed in Occume?
    Red oak, soaks up water like a sponge... soaks up CPES like a sponge too.

  15. #15
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    Default Re: Sheathing with solid lumber

    I wonder what the hull is to be made of? Maybe concrete. Then sheathed with wood. And then glassed. Unusual, but what the.

  16. #16
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    Default Re: Sheathing with solid lumber

    Of course you can use solid lumber, that's how boats have been built for 10,000 years. But choose proven methods. Maybe you want to use double planking. Use a flexible adhesive bedding in between the layers.

  17. #17
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    Default Re: Sheathing with solid lumber

    Quote Originally Posted by Jay Greer View Post
    Don't forget folks there is also balsa wood available for encapsulation! It even rots faster than poplar! Note that, I have some property for sale that is forested with a stand of amber snake oil trees! You might find that to be of interest as a boat building material as the snake oil warrants to offer rot protection prior to application. It also cures pips, wens, piles and pellagra and missplaced affections. It will polish the piano and cure the cat! It also is bonded to insure it not to erode, keyrode or implode other than within your line of credit.
    Bird
    Don't you mean diesel oil trees? Copaifera langsdorfii You can run yer diesel on the sap. Talk about firewood.
    You never did get over the awkward place that Dave Carnell put the ethylene glycol. Or was that Ian.
    Management is the art of counting beans. Leadership is the art of making every being count. --Joe Finch

  18. #18
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    Default Re: Sheathing with solid lumber

    The main reason is the one Todd gave, you dont mention the size of boat and that pays a part. I presume its trailerable and less than 500 lb's as most questions like this tend to be for that type of small cheaper boat. If its bigger, much bigger then you need to use tried and tested methods for "sheathing".

    Occume is perfectly fine if it has no voids and builders think of it as a construction medium that requires x,y,z treatment and it may well be perfect for your build. If you insist on sheathing with solid timber then I suggest you use something like 3mm veneers stapled and glued diagonally until you have the required thickness. It does not matter much what timber you use then as the epoxy will seal it.

    Good luck
    whatever rocks your boat

  19. #19
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    Default Re: Sheathing with solid lumber

    Seeing you are located in Colorado, this calls for a road trip to procure some Sitka spruce for your boat.

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