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A diffent kind of stitch and glue

Discussion in 'Strippers, Stitch-n-Glue, and Other Wood Composite' started by JEM, Dec 5, 2008.

  1. JEM

    JEM Canoe and Kayak Designer

    I've been toying with an idea. Maybe somebody has tried it already. In any case, thoughts and ideas appreciated.

    I design and sell canoe and kayak plans using the stitch and glue method of assembly. But I've always wanted to build canoes for retail sales. Not on the level of American Traders, but maybe 3-4 a year.

    I'm pretty confident trying to sell a stitch-and-glue canoe, even if it's like 12 panels to make a mostly rounded hull, would not command a price tag of $1500+, which is the price point I'd like to be at.

    So I've thought of building it wood-canvass style except no ribs and using the fiberglass instead of canvass. I really like the look of it and I think it would have some mass appeal.

    To achieve the strength without ribs, I'd using 1/8" marine ply and multi layers of thin fiberglass inside and out. I have theoretical scantlings already calculated.

    Determining of the 1/8" ply will conform to the hull shape will have to be an experiment. I figure I'll set up the forms and simply just have to try it. If it doesn't work, I'll strip-build over the forms instead. I've designed a simple trapper-style canoe for this experiment. I should know if it'll work with the first 6-8 planks or so.

    The catch is the board lengths. If I'm using marine ply, longest board I can use is 96" (8'). Since the goal is no ribs, getting the boards to join ends with sufficient strength is ...well.... gonna be tough to do. In stitch and glue building, you use a butt block or fiberglass splice. But it would be near impossible to install these on the inside of a hull while its on forms.

    So I got to thinking further, what if I used ribs except make them from 1/8" plywood and laminated 3 layers over the stations? A bit of extra work but it would eliminate the need for steaming and then I could glue (with thickened epoxy) the planks to the ribs. No nails or tack to clench and become loose one day.

    Ok... yea....I know... sounds like trying to build a better mouse trap with the Rube Goldberg mentality. But it's just thinking out loud and it's something I need to either try or get out of my head.

    So would you all join in with thoughts and ideas of how to make it possible? Just for fun. :p
     
  2. Todd Bradshaw

    Todd Bradshaw Sailmaker

    If you can find a Gougeon "Scarffer" attachment for a Skilsaw, you can pretty quickly, easily and accurately scarph full sheets of plywood to any length you need with an 8:1 scarph that for all practical purposes, doesn't lose the strength of the plywood. Butt blocks and fiberglass splices are pretty crude by comparison.
     
  3. OP
    OP
    JEM

    JEM Canoe and Kayak Designer

    I'm thinking it might make more sense to try like a 7' boat book shelf with this idea. If it works, then worry about scarf joints.
     
  4. Dave Wermuth

    Dave Wermuth Who hid my paddle?

  5. OP
    OP
    JEM

    JEM Canoe and Kayak Designer

    Not quite. I have similar designs like the Sasquatch:

    http://www.jemwatercraft.com/Sasquatch.php

    But both are still stitch and glue and still do not have the fully rounded out hull in the bow areas and are based off of lofting lines instead of rounded surfaces.

    My idea may end up leading right back to a multi-panel stitch and glue design. But I still want to try and achieve results using the wood-canvass method of hull planking.
     
  6. OP
    OP
    JEM

    JEM Canoe and Kayak Designer

    I don't have a female fiberglass mold to work with.
     
  7. woodenkayakguy

    woodenkayakguy LOVES Wooden Canoes

    Matt I have built both the millcreek kayak and selway's peterborough(sorry didn't know about you back then)As you probably know and have seen in the past few years there weren't a lot of nice looking canoe plans out there because everybody went with (in my opinion) to few panels per side,recently designers such as your self have started designing 5,6 and even 7 panels per side.If you were to build a wooden mold then tack the ly to it and plank (with marine ply) in a similar fashion as the original wood canvas boats then you would get your patterns and a reasonably fair curve. By the way the sasquatch looks good,getting closer to the smooth round lines of a canvas boat
     
  8. OP
    OP
    JEM

    JEM Canoe and Kayak Designer

    Thanks.

    I've been playing with different options in my software and it's helped identify which spots will be troublesome. It will be in the "cheek" area... i.e. low bow stem areas. But I think I know how to overcome that.

    The wildcard will be if I need ribs or not. If I don't, that would be fantastic and I'll write a dang book about the method! :p

    Not really a new idea... just a combination of old ones.
     
  9. woodenkayakguy

    woodenkayakguy LOVES Wooden Canoes

    If you look at how the planking is done on a wood canvas they didn't use full lenght strips instead they used several shorter pieces in the middle
     
  10. OP
    OP
    JEM

    JEM Canoe and Kayak Designer

    That's part of my dilemma. The end of the shorter planks butt together over a rib. If I go with a no-rib configuration, then I'm worried I'll need a scarf or butt block.
     
  11. woodenkayakguy

    woodenkayakguy LOVES Wooden Canoes

    I understand what your saying but a lot of info I've seen recently suggests that just a butt joint is strong enough with the fiberglass cloth,maybe an extra layer over the joints?
     
  12. OP
    OP
    JEM

    JEM Canoe and Kayak Designer

    That's exactly what I was thinking. If I limit the adjoining/butt areas to mid ship and then say about 3' either side of midship, I can just add an extra layer of cloth in the middle 6' of the hull.

    But I'll determine exactly how that will work out as I go along.

    I do plan on staggering the joints.
     
  13. OP
    OP
    JEM

    JEM Canoe and Kayak Designer

    I do intend on having thwarts if that's what you mean.
     
  14. OP
    OP
    JEM

    JEM Canoe and Kayak Designer

    oh ok. I see what you mean now.

    It will take some experimentation to see if it works out. I know it won't be 100% fair like a wood-strip canoe.
     
  15. Bill Mackey

    Bill Mackey LOVES Wooden Canoes

    Why plywood??

    In the book "The Canoe" by John Jennings on page 190 they show Walter Walker building a canoe with 3 basswood planks from keel to gunwale. I am working on a plan to do that on a strip canoe. I just don't have enough basswood to do it right now and it is not available here in Colorado. But I hope to cure that problem on a trip to Michigan in May. Basswood will bend using boiling water only and I am more than sure that it will make the curves on a good strip mold.
     
  16. Tim the Inspector

    Tim the Inspector Kayakaholic

    Have you seen the Glide Easy?
    http://www.svensons.com/boat/?p=RowBoats/glide_easy

    I'm a little skeptical as to how straight and symmetrical this one would be without any sort of form other than the single centre bulkhead. Hopefully other parts of this at least give some ideas.

    -Tim
     
  17. Bob Holtzman

    Bob Holtzman Wannabe

    A tapered glued joint should work fine without f'glass or butt blocks, and the expensive Gougeon taper jig isn't essential- it just makes it quicker. Most books on stitch and glue construction (e.g., Kulczycki: The Kayak Shop; Stitch & Glue Boatbuilding, and Dierking: Building Outrigger Sailing Canoes) show how to stack the plywood with the ends staggered, then sand or plane the edges down to an 8:1 slope. You can go even shallower than that, and on very thin plywood. Epoxy will do fine (or resorcinol, if you produce really good, flat surfaces) for joining the bevelled edges. Little clamping pressure for epoxy; lots for resourcinol.
     

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