Wanting to build a stitch and glue gheenoe-like craft

Discussion in 'Boat Design' started by DentonDon, Aug 26, 2013.

  1. DentonDon
    Joined: Aug 2013
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    DentonDon Junior Member

    Just outdoor ply. This is a $100 project. If I do a good job the next one will be built of marine grade ply. This one will be sealed with thompsons and then painted. Seams will be sealed with Ken Simpsons Tape and Glue II process.
     
  2. El_Guero

    El_Guero Previous Member

    OK. Are you modeling first, or just adjusting as you build?

    Are you going to oversize this a little, from your plan dimensions?
     
  3. DentonDon
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    DentonDon Junior Member

    I will make a small model out of cardstock to evaluate dimensions. Not sure what you mean by oversize... But I'll be posting an updated drawing sometime soon.
     
  4. El_Guero

    El_Guero Previous Member

    Some of the nesting boats seem to fit inside of each other tightly, so I was wondering if you were going to increase the size on yours a little? Or, will your plans be large enough?

    thanks.
     
  5. Skyak
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    Skyak Senior Member

    Thompsons water seal makes paint not stick as far as I know. I don't know that glue method either. Stitch and glue is almost always done with filled epoxy and fiberglass. The only exception I know used glue and a 'chine log' -it wasn't cheaper or less difficult, but the glue was not toxic so kids could do the build.

    My recommendation is stay with the epoxy and glass the edges -it's by far the most abused part, it's life will be the boats life. Forget about spending on sealant or expensive paint -use good leftover house paint and whenever something scrapes through paint the scrape after it dries.
     
  6. DentonDon
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    DentonDon Junior Member

    Nesting plan should work. New drawing coming today.

    Skyak: Here is the link to the tape and glue process. I have already done some testing of joints and have found this method to be every bit as strong as advertized.

    Titebond III and fibatape is 1/4 the price of epoxy and glass so its the only way this project stays on budget.
     
  7. DentonDon
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    DentonDon Junior Member

    Alrighty, here is the updated plan with taller sides (15") at the lowest point.
    Also note that I've scrapped the 3 sheet idea as it just didn't provide enough tor the size of boat in a nesting style. I might post a pic of the cuts on sheets later.

    [​IMG] Uploaded with ImageShack.us
     
  8. Skyak
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    Skyak Senior Member

    I guess it's a case of nothing ventured nothing gained. I can understand not wanting to use expensive glue on cheap plywood. There is a thread in the building section of this board that is dedicated to waterproof glue alternatives but it sounds like your decision is made. I can see the glue being adequate to hold significant flat areas together -like a chine log, but I don't know how it will fill gaps or have enough contact area on the edges of the ply. Do tell us how it goes. I am inheriting three sheets of cheap 1/4 ply (deemed unworthy to deck my jet dingy) so this is of interest.

    I see the boat got much smaller but now fits inside your car. The battery in the widest section of the boat should improve stability. The tight spot in the nesting plan is where the front of the aft section fits in the aft of the middle section. They are the same size so the topside flare accommodates the stack. You might fit some metal corners in that edge for strength. You can put some foam in the sides, rasp it to fit snug and cushy, then glue fabric over it to protect.
     
  9. DentonDon
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    DentonDon Junior Member

    You nailed it on the head with that first part. This is a poor mans boat! :)
    And yes, I made it a tad smaller to fit in the matrix but taller sides for stability/safety.
    I'll post a model in the next few days to show everyone
    Thanks again for the advice!
     
  10. DentonDon
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    DentonDon Junior Member

    Here are the cuts on the sheets. Note that the sheet with the side and bulkhead cuts is doubled making a total of 4 sheets.

    [​IMG]
    [​IMG]
    [​IMG]
     
  11. DentonDon
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    DentonDon Junior Member

    WARNING: PHOTOS OF VERY CRUDE PAPER MODELS
    [​IMG] Uploaded with ImageShack.us
    [​IMG] Uploaded with ImageShack.us
    [​IMG] Uploaded with ImageShack.us
    [​IMG] Uploaded with ImageShack.us

    the model did show a couple of mistakes i made with the dimensions of some pieces but I'm pleased overall.
    Remember friends this is a first build and not a yacht. :)
    Thanks agian for the advice
     
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  12. boat fan
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    boat fan Senior Member

    Good stuff

    I hope you will come back with the results.

    Interesting project.
     
  13. Skyak
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    Skyak Senior Member

    Good work so far on a worthy project. I have some comments that might improve it.

    4 sheets not including buoyancy or seats is pretty inefficient for a boat this size. It doesn't bode well for cost or weight. If you scooch things around you should be able to get the buoyancy boxes and gunnels. Which brings the next point -structure. You are going to need structure at edges and corners. 1/4 ply edge to edge is not enough area for glue. Stitch & Glue normally makes fillets with filled epoxy. I am not sure your glue has an equivalent, but I do recall seeing tightbond in a recipe for advanced paper mache. The next best way is to cut thin strips that you can bend to fit corners and edges.

    The shear seems exaggerated and all in the ends. I think you added it to the rocker (which also looks excessive to my eye but I think you took someone elses advice) but shear is considered from the waterline. My recollection of the classic shear line is from a peak at the bow the low point is at 3/4 of the length to the transom which is half the distance from low to high. Your boat your taste, but look at some boats you think are good looking and consider their percentages. If you look at the rocker of advanced flat bottom boats (big riverboats, racing scows) you will see a similar situation where the deepest point is in the first third of the length and the overhang is flat to the transom -much like the shape of a wing.
     
  14. DentonDon
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    DentonDon Junior Member

    Skyak, I think I understand everything you're throwing my way and I appreciate the input. I will have to investigate the possibilities of a titebond fillet or possibly incorporate chine logs for structural strength.

    Also, are you saying that I should make my design work with 3 sheets instead of 4?
     

  15. DentonDon
    Joined: Aug 2013
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    DentonDon Junior Member

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