Free stitch and glue software with plans output

Discussion in 'Boat Design' started by 1VanDerH2O, Mar 18, 2010.

  1. 1VanDerH2O
    Joined: Mar 2010
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    1VanDerH2O New Member

    I have been a lurker on this forum for a little while now and decided to jump in with what may be a pretty easy question. Maybe not. Couldn't find the answers anywhere in the design forums. And I could be looking to do something that is pretty impractical.

    My Goal. To build a simple two person outrigger Canoe using stitch and glue with a thin, fairly bendable (steamed -likely) plywood. Since Outrigger canoes attain stability via the Ama and Iako set up, the boat can be pretty narrow (beam of 20 inches) and does not need a hard chine for stability. Think of the rowing shells you see on the river, pencil thin super fast hull design. Then think, maybe not that pencil thin but.. close.
    length - 22-24ft,
    beam 20in
    draft around 6-8 inches.
    Displacement 400ish.
    Rocker - Very little. perhaps 8-10 inches.

    What seems like would be a simple approach would be to design it in something like Stitch and Glue light, print out the plans and go build a model to experiment with. The problem is that Stitch and glue light charges for those plans. In addition, it doesn't seem to allow you to choose how many pieces you would like in the output. Since I plan to bend the ply quite a bit I hope to avoid having too many chines in the final construction. Ideally I would love a completely smooth hull, with no chines.

    Questions.

    -Is that Doable? (No chines, smooth hull). Could you actually go as far as to have two long panels and book end them with the right cut and bend to come up with a painfully simple construction process with only one stitch location at the centerline?

    -Does anyone know of a free software program that has the user friendly components of Stitch and Glue light and provides the output plans for free?

    I have been playing with Freeship and like how powerful it is but I don't think I understand how I can get an output out of it that takes me to the next step of building it from plywood. Admittedly, I am new to Freeship and may have not discovered how the software makes this happen just yet. Instead of spending a few more hours experimenting with the software, reading manuals etc I thought I would just ask the experts...just to make sure I am on the right path. I have also looked at the Hull program but... just not getting how it works and gave up on it. Looks like it only allows you to design with the assumption that no plywood would be bent to form any radius.

    - Does freeship allow you to do what I am trying to do as described above? Meaning, will freeship allow to design for stitch and glue and also allow you to bend each panel and provide an output based on this?

    Any help would be appreciated. I have a lot to learn about the tools out there, just trying to learn more about what is possible and what tools to put my time into studying.
     
  2. Jeremy Harris
    Joined: Jun 2009
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    Jeremy Harris Senior Member

    As a non-expert, but someone who's done something similar, I'd take a look at tortured ply. Here's a link to some models I made whilst playing with this idea for making long, narrow hulls: http://www.songofthepaddle.co.uk/fo...ric-propulsion-ideas-(and-introduction)/page2

    I found it easier to just experiment with models than to faff around with CAD, as somehow, seeing real bits of wood turn into real boat shapes in your hands just seemed to give me a better idea of what would work. The local model shop had stocks of thin plywood and spruce strips, that made building models pretty easy.

    Jeremy
     
  3. ptoliv
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    ptoliv Junior Member

    Aren't station molds used in tortured ply, strip building might be a good way to get a smooth hull and a stem would help with hull strength.
     
  4. magwas
    Joined: Oct 2009
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    magwas Senior Member

    My design flow for "traditional" stitch&glue, with developable plates:
    1. Design the hull in Carlson's hull software. Or better chose one from the many models available.
    2. Import it to FreeShip
    3. Do modifications which retain developability (scaling, and getting whole plates in one edge extrusion, cutting of parts of plates).
    4. Go to "develop plates", and export it in dxf
    5. Import it to qcad, and do finishing touches: emphasize cutting lines and put hole positions
    6. Print and build it.

    I think with bendable plywood developability would still be an issue, maybe it would resemble to steel origami?
    I do that like the above, but in the qcad stage I merge plates in a way I think it would fit.
    Kayak (i.e more of the deck is not a hole) is easier with origami than canoe if you do not want a chine in the upper part: in midship you will end up with nearly vertical walls otherwise.
    I hope my last paragraph is intelligible, I am not a native speaker.
     
  5. Ilan Voyager
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    Ilan Voyager Senior Member

    I made five 18 feet catamarans in compounded plywood for regatting, so I have now some idea how this method works. The catamarans had very different shapes and showed that within the limitations of the system you can get, with some compromises, what you want.

    First get some lights on boat building, plywood, and compounded (or tortured) plywood. There is one only book for that; Gougeon Brothers on boat construction, there is a complete and detailed chapter on compounded plywood. The primordial investment.

    After reading (and understanding) this book, go to the practices; make models in airplane birch plywood. Buy 1 full sheet of 4 feet, not in a model shop, it's too expensive, but in a specialized wood supplies for airplanes. Pretty expensive but far less than a full size mistake. Make models, as many as necessary. That works. You'll get doable and fair hulls without spending hours of CAD fairing....You have also to understand basic principles of boat design. Do not waste time with a computer CAD, experimentation in a small recipient will give you displacement and center of displacement without "big" maths. An excel sheet will do the remaining simple calculations.

    You will be using okoume naval plywood and only that. Expensive but no other way. No need of steam, but hot water and some times isopropyl alcohol. You'll see experimenting with the models. It's all eyeball construction.

    Other way is stitch and glue. Can be very good, and do not be worried by chines. Well designed chines can be an advantage. The method is more foolproof when building than compounded plywood. In this case the Carlson is largely enough.

    Third way, buy good detailed plans if you find one convenient design for you. The little expense and the big amount of time saved are more usefully invested in the building, always longer than believed.

    I do not see the interest of learning the FreeShip and the consequent hours spent on a computer for a so simple project (I'm a white bearded Naval Engineer...). Keep the night hours for your girl friend or wife, it's funnier and healthier. FreeShip is a rather good tool but it's as dangerous as a electric planer in not experimented hands for designing... Do you need a computer driven hydraulic hammer to hit a nail in a plank?
    Do not have fascination for the apparently precise ciphers given by a software. First generally these ciphers are false on a so small boat, second these ciphers, even exact, are useless in a project like yours.
     
  6. messabout
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    messabout Senior Member

    The Gougeon brothers book is very instructive about tortured plywood as mentioned above. Tornado class catamarans are sometimes built with this method. I suspect that you could get plans and instructions from the Tornado class group. Use half a tornado for your proa.

    If you want radiused chines while using flat panels for the majority of the hull, there is a way. At the intersection of sides and bottom use strip technique to make the chines round or any shape you might choose. That is a composite technique that combines strip with stitch and glue. Matter of fact stitching would not be required as you will have made a suitable set of forms and ribbands.

    I warn you that the stitch part of S& G construction is a misery. I will argue that S&G is more work and less exact than building a decent construction jig. The process of drilling a zillion holes and later filling them and sanding the fill, is not my idea of efficient building practice or fun either.
     
  7. 1VanDerH2O
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    1VanDerH2O New Member

    Useful information from all. Thanks again for the advice. Very Very helpful

    I think that adapting a Catamaran design would work well for an outrigger canoe.

    Any resources on good catamaran templates?

    That maybe a great exercise in 'creative theft'. My experimention ply has been 'doorskin'. It is a 1/8 inch mahogany ply that comes in 7 X 3 foot sheets and cost 9$. Easily found at building supply stores. I was able to get it to radius around a 20 inch diamater curve without hot water/steam treatment. I thought I was on my way but then found that it was a little difficult to bring that forward to the bow in a flowing manner. As I tried to force it into the curve i wanted i popped a few stiches and the Ply creaked cracked in protest. I do think that it is possible though if I have some well designed stations to tack it to. Like one of you mentioned, if I can build some good stations, I may be able to skip some of the stitching. The other part to this, which led my explorations in design software, is to have the right shaped cut out of plywood that will direct my bending efforts with the ply. I see great potential with Jeremy's example of the narrow electric boat. If you could imagine getting that design down... You would have one seam down the centerline and that is it. Should make for easy construction.

    I will experiment with a few things here (hands on and virtual through computer) and make sure I leave time for My Fiance (who has better lines than any boat I could build). ;)

    Will report back on any interesting findings... on the boat that is.
     
  8. ptoliv
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    ptoliv Junior Member

    I have built with 1/8" lauon door skins. Some are good and others are not. The cracking is usually caused by voids in the center ply and most of the skins are not manufactured with water proof glue. The 4x8 sheets are better quality usually. I used a heat gun to bend after a light soak. I tried several suppiers until I found some good sheets and built an 8" pram. It was a v-bottom hard chine design go I did not have much trouble with the bends at the bow. Very light boat.
     
  9. Jeremy Harris
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    Jeremy Harris Senior Member

    One thing I discovered when torturing plywood into semi-compound curves was that it's the compressed face that needs the most water/steam/heat. It seems that wood fibres don't mind stretching too much, but they very much object to being compressed.

    I initially thought this was a bit counter-intuitive, as logic seemed to suggest wetting/heating the outside face. Once I found that ply would bend more easily with a hot, wet rag on the inside of the bend things were a bit easier.

    Jeremy
     
  10. Ilan Voyager
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    Ilan Voyager Senior Member

    1VanDerH2O you're welcome. And good luck. Buy the Gougeon Bros book, expensive but truly worth. You'll find also the offsets for a class C trimaran, a good start idea for the boat you want to design.
    Compounded plywood starts from the skin, bulkheads are fitted and added later. The most important is the deck jig. I counsel you one with supports so yo get a straight boat. Second point, the keel fiberglass width as it controls the fullness of the hull.
    You'll learn fast with the models.
    Do not use skin door. No waterproof glue and uneven bending. You could find very good skin doors 20 years ago. It's not more the case.
     
  11. Ilan Voyager
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    Ilan Voyager Senior Member

    It's in reality perfectly logical: wood has very little elongation ( 0.8-1.2 %) so the outside (in tension) won't have noticeable elongation, and will fail by tension splitting if too stressed. The inside (in compression) will try to rearrange the cellulose cells by "shortening" or buckling them. When you apply hot rags, the heat softens the lignin (the "glue" keeping together the straws of cellulose) and everything can "slide" in place. After the plywood will be stabilized by the epoxy resin, which will fill and glue in place all the damaged cellulose straws and eventual micro fissures.

    The method Stressform of the Gougeons Bros exploits totally this particularity.

    The matrix plywood-epoxy-fiberglass is very effective. As the skins are rather thin, precautions must be taken with the bulkheads with large light filler fillets. Blue structural styrofoam 1 inch thick makes excellent bulkheads on small cats.

    Compounded Plywood can give very light structures: my last catamaran, 18 feet long, almost 11 feet wide, 18 m2 (194 sq ft) sail on a 30 feet mast weighted 89 kg (196 pounds) complete ready to sail. You need to go to carbon nomex for a lighter similar cat: the cost is not the same...
     
  12. messabout
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    messabout Senior Member

    And for some really severe bends in wood, you can soak with household amonia. Wicked stuff but it has a remarkable ability to make wood bendable. I do not recommend this method because It is a hazardous scheme. But it works.

    Another method for building a curvacious boat is the cold molding method. That method is also described very well in the Gougeon book. Cold molding makes a beautiful boat that is both light, strong, and can be left nearly devoid of internal structural elements. Labor intensive but well worth the effort if you wish to make a really snazzy boat. Tortured ply has constraints that are concerned with width/depth ratios which may force the designer into compromised shapes. Cold molding has no such restraints.
     
  13. 1VanDerH2O
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    1VanDerH2O New Member

    Thanks again for the help. I have the book on order and will start there to build up more boat building knowledge and will mess around with models in the meantime. Will hit you up for some more information when I am to the next stage. I am sure I will be in touch with the next stage of questions.
    Until then...
     
  14. idkfa
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    idkfa Senior Member

    http://www.carlsondesign.com/#Fun_Shareware

    This is basic software but VERY useful for small hard chine hulls. Comes with many, many free hull examples, all of which can be very easily modified. Read the tutorial, it will produce panels and frames, etc.
     

  15. ancient kayaker
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    ancient kayaker aka Terry Haines

    A lot of good advice; as a canoe builder perhaps I can add a few observations.

    Stitch & glue is time consuming although some disagree with that. The longer and narrower the boat the more difficult it becomes handling the planks, which are often too fragile to support their own weight especially if they are wider at the ends than at the middle. For a long skinny canoe I would be surprised if you have to resort to steaming or hot water to get the planks to bend as required.

    You must have to have the plank developments for S & G and FreeShip will do that for you: The problem with FreeShip is you have to start off right! Suggestions for using FreeShip are -

    Don’t use too many control points, it makes it more difficult to get a fair hull. Vertically you will need 1 more than the plank count per side. Longitudinally, 3 will provide a sharp-ended canoe shape, 4 will allow a more rounded shape, more is needed only for unusual hulls or very bluff bows and stern.

    Correct longitudinal location of control points is key to the use of FreeShip. I first picture the curve I want, then imagine I am bending a batten to that curve. The points along a batten where I would have apply pressure tell me how many control points and where they need to be.

    If the first try is way off just start a new model with different parameters.
    The Transform, Scale tool is very powerful and useful.
    For a new hull FreeShip will give you a transom; you close it for a canoe by setting its control point Y values to zero.
    Check for leaks (Tools, Check Model), these should only be along the gunnel.
    Make the chines into creases (CTRL-click an edge, Edge, Crease).
    Make the planks developable (Layer, Dialog).
    Create layers for each plank (Layer, Auto Group).
    Then use Tools, Develop Plates. You can print or save these to a bitmap.
    Note that you can move the planks around and flip them to optimize use of ply material.
    To locate stations use Calculations, Intersections.

    FreeShip will display plank deformation as a red area (Mode, Developability Check). It is not sensitive to plank material characteristics but it tells you where the worst problems are likely to be.

    I used to use Luan door skin but the quality deteriorated to the point where it became useless even for models. I find I can build directly from FreeShip’s developments, but if I am worried about problems with tortured ply I use the Developability Check to ID the worst end of the worst plank and test bend a half a plank. I keep offcuts of the thinner marine plywoods for use on scale models of suspect planks.

    If using a construction jig put in stringers along the chines so you can take off the plank developments from the jig.

    My own method uses chine logs, together with the inwales they are glued along the plank inside edges with the planks flat. This stiffens the planks for handling during assembly and allows me to get a fair hull shape with a minimal construction jig. Even if you stay with stitch and glue, you can pre-glue the inwales (or clamps) to the sheer planks, which are often the most fragile. The other planks tend to be tapered and are therefore less delicate.

    Good luck and don’t forget to post your progress! We like to see the baby growing!
     
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