stitch and glue + -

Discussion in 'Boat Design' started by William C. Wins, Dec 29, 2011.

  1. William C. Wins
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    William C. Wins Junior Member

    I have plans for a plywood wooden 26' tug. Choice is stitch and glue (as practiced by Sam Devlin) or the more traditional full lofting and framing. I built an 18 foot catboat using tradional method but have never done stitch and glue. Opinions on the two methods?
     
  2. tom28571
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    tom28571 Senior Member

    Do the method that appeals to you. Since it is a tug, the total weight and strength to weight ratio advantage of S&G is not a significant factor.
     
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  3. rasorinc
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    rasorinc Senior Member

  4. Petros
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    Petros Senior Member

    I should think that S&G would be both much faster to build and costs less in materials. I would also suspect that S&G hulls would have less maintenance/repairs over it useful life too.
     
  5. eyschulman
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    eyschulman Senior Member

    Agree 100% with Petros. Use good plywood and good epoxy see what Sam Devlin is useing I think Mas low volitility high solid stuff easier to work with. build it on upside down bulkheads and temp. ply forms. Look at some of the build pictures on Sams site.
     
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  6. lumberjack_jeff
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    lumberjack_jeff Sawdust sweeper

    Sam uses MAS epoxy but west works fine too.
     
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  7. PAR
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    PAR Yacht Designer/Builder

    As with all building methods each has it's good and bad points to consider, these two aren't any different in this regard.

    Traditional methods require you purchase, cut and fit more "boat parts" such as frames, floors, etc. Typical taped seam builds (stitch and glue is the technique, taped seam is the method) often can eliminate most if not all of these boat bits, instead relying on fillets, fabrics and goo. To some, cutting and assembling all these traditional boat parts is quite rewarding, I know I enjoy it. The "goo factor" is also much lower generally, in fact you might be able to skip these wonder stick'ums entirely.

    This said, a taped seam build does have fewer pieces to cut out if well designed, but material cost savings is usually offset by additional costs, such as fabrics, fillers and of course goo, lots of goo. Epoxy can be difficult for some to get use to and it's messy, sticky and will have a substantial learning curve too. So, savings in time and boat pieces fitting, compared to a traditional build, are counteracted to a large degree in time and costs.

    In the end a taped seam build can look much like a production boat, with no frames, nicely radiused corners and well embalmed wooden elements. Of course you'll spend a lot more time sanding all these wonder goo'd surfaces and cutting hunks of it out of your hair, but it could be worse.

    As to which is better, well neither is. They both have advantages and disadvantages. I have both, some of my build, others quite classic. I enjoy both, but I'll add there's something enjoyable about going below a well founded, traditionally built yacht and seeing frames, ceilings and a massive stem assembly that can bash through things, that might get in your way, as my 1960 Atkins has. If someone bumps me, I don't get too concerned, knowing I have 1 1/4" thick topside planking, with 5 1/4" molded frames backing them up. On the other hand, if I had a similar size (40') taped seam boat, I'd have several layers of fabric over at least 1/2" plywood, which would offer more abrasion protection, though I wouldn't feel as good when hitting a hefty log, with a chunk of pipe sticking out of one end, as I do the carvel build. I find it's easier to maintain the taped seam builds, but harder to repair then traditional construction.

    In the end, you'll have to weigh your skills, tools, desires, allergies and other constraints while making this decision.
     
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  8. philSweet
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    philSweet Senior Member

    Will, when you say tradional, do you mean carvel plank on frame or old style preglue plyboat methods with frames and stringers? Stitch and glue might be a bit faster if you have adequate space. What you want to avoid is having to mix up little six ounce batches of goo. If you have the space to do three days of carpentry and then set up the epoxy and run a few gallons, that is fairly efficient. Is there a promo picture or some free study plans that you can post without running afoul of the plans provider?
     
  9. William C. Wins
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    William C. Wins Junior Member

    Traditional here means plywood on frame, relying more on mechhanical fasteners than on epoxy, although it has its placed. Sam Devlin has submitted a bid to redesign his Tugzilla--a 26' full displacment hull--to 28' with a semidisplacement design for stitch and glue construction. He also has a video of the s&s technique. As this project is a one-off design, it becomes a major challenge to learn good epoxing techniques. I don't think I would save any time or materials in a one time effort. At least that is what I am learning from talking with others. I have built a 19' hard chine catboat with frames and plywood which, at 17 years is still going strong. I have not explored with Same a more traditional lofting of the boat.
     
  10. michael pierzga
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    michael pierzga Senior Member

    Stitch and glue makes a good boat ,but the technique is messy with miles of plastic and masking tape ,mountains of sandpaper, truckloads of disposable gloves and respirators, plus much time pushing board sanders.

    Traditional construction makes a good boat, but requires top class materials ,a first class design and good craftsmanship skills.

    In the end it up to you.

    You might have a look at the stout 25 ft trawler types from Paul Gartside. Also a few double planked boats in his collection

    http://store.gartsideboats.com/collections/power-boats/products/24-ft-motor-cruiser-design-143
     
  11. Milehog
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    Milehog Clever Quip

    Probably the best way to decide would be to build a Devlin Polliwog or similar stitch and glue dinghy as a test run.
     
  12. yipster
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    yipster designer

    Wise words ive heard bfore
    also over a sudden size and weight s+g gets cumbersome
    may need a mold or crib anyway
    no, havent build but did read up on s+g
     
  13. eyschulman
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    eyschulman Senior Member

    This is 48ft S&G on bulkhead mold.
     

    Attached Files:

  14. PAR
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    PAR Yacht Designer/Builder

    From a technical stand point, taped seam building does have a practicality limit. Over this limit, it's a more traditional build though taped seams are still incorporated. The hull above is a typical example, with both longitudinal and athwart stiffeners to reinforce panels.

    Stitch and glue techniques are generally reserved for craft small enough to "fold" into shape, while the seam ties maintain relative alignment. After a bit (around 20') you need some station molds to help "man handle" the panels. Personally, I'm not a stitching fan, just too much bother, when tacks, screws, tape, ratchet straps, Spanish windlasses, etc. can work just as well, without a thousand holes to fill. These are still taped seam builds, but the seam assembly technique is different.

    Assuming the hull's scantlings are scaled to the demands of the SOR, there's really no "too big" of a taped seam build, though other materials become more cost effective in these larger sizes (over 30').
     

  15. William C. Wins
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    William C. Wins Junior Member

    It would seem to me that with stitch and glue, you must be very consistant in how much glue to apply which is a matter of quality control. Too little and something could delaminate, too much is just that, but unless you have done many hulls, as Sam Divlin has done, consistancy is somewhat hit or miss, especially when one is doing a one-time one off. Mechanical fastenings, on the other hand, give me a certain consistancy of strength, especially on a larger boat. This is what I am learning from this forum. In the end the decision is mine, but I do appreciate all the good advice that many of you have given to this enquiry.
     
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