"Self-jigging" flatpack kit for metal hulls

Discussion in 'Sailboats' started by cadmus, Mar 31, 2009.

  1. cadmus
    Joined: Mar 2009
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    cadmus da boom hit'um 1ce 2often

    Remember the old BT global Challenge boats. 10 identical/1design boats, 72', steel, raced around the world the wrong way. They were crewed by normal (wealthy) people who paid for the experience... i think... while skippered by a pro...maybe?

    I remember reading that they were made with "self jigging" plate steel components all laser or plasma cut to fit together without measuring or cutting, creating 10 identical boats (8 in UK 2 in china). In addition to the name "selfjigging" the term "flat pack" was assigned as no pieces were bent metal. It was all plates so they all arrive on a lowboy like a $200k snap together model.

    The company i see advertising this method is Corus. see this flyer:
    You may have to play with the background colors on your PDF reader, the font is white on white background?
    http://www.staaltagmester.dk/file_source/StaticFiles/SHIP_KITS_DATASHEET.pdf
    or also found here
    http://www.corusservicecentres.com/...Units/ServiceCentres/SHIPKITSLeaflet2page.pdf

    :?: What is this "SELF-JIGGING" FLAT PACK kit? Who has used, seen, or heard of this building process? Does anyone have photos, plans, napkin examples, or anything that will give me an idea of how bulkheads, stringers, surface plates, and other framing ties into each other? How "self-jigging" is it? Will this prevent even me from making an asymetrical boat?


    I have ideas as to how i would do this... but if someone knows how the pros are doing it i would love to hear about it.

    :?: ALSO. low priority I recall the BT global challenge boats used a Triangulated Irregular Network (aka: TINs) for the steel sheathing rather than the traditional long chines. Then smoothed out with filler, maybe? (because they sure didn't look like metal boats, very curvy) Does anyone know about this method? Are the triangles bent or curved or are they welded onto the frames flat?

    Many Thanks
     
  2. sharpii2
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    sharpii2 Senior Member

    Hi, Cadmus.

    They probably used slots and tabs, where a small tab, on a bulkhead, say, is inserted into a slot like hole in the side panel. After it is inserted, it is welded, locking the two pieces together at a specific point quite securely, nothing like a tack weld. The whole vessel can be assembled this way before any long seems are welded. With today's extremely accurate CAD design, boat parts can be cut and shipped on an as needed bases, where some parts are already welded together before others have even been cut.

    The TINs thing you mentioned is probably the way they determined the hull plate flat shapes. Most likely the boats you mentioned were first chine constructed then faired with with fillers to give them a rounded shape.

    I don't think facet construction was actually used, because, although steel welds have a high percentage of the strength of the surrounding metal, they do have weaknesses. I would never put one on a hinge point, like a facet joint. All my facet joints would be bends with the welds going on the flat portions of the facets.

    I don't consider chines hinge points because they are rarely straight in three dimensions and are almost always cross braced with frames and bulkheads, so they cannot act as a hinge.
     
  3. cadmus
    Joined: Mar 2009
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    cadmus da boom hit'um 1ce 2often

    IKEA boats

    Thanks Sharpii2 for the response. about the TINs. So you think it was long chine construction. I too worried about the small triangles being held only with face welds... but if they are big enough triangles to rest on several cross members does that solve the problem or must the weld line sit directly over longitudinal and cross framing members? It is possible to do that with weird angles but it would be a cluster.
    ___________________________________________________

    More self-jigging.
    Folks may have seen self jigging structural components in building construction, it is kinda uncommon. Rather then hauling I beams a company cuts 2 flange sheets with slots and 1 or 2 (then it becomes an II beam) web plates with tabs. the tabs only fit in the correct configuration of slots. then you weld um. often the beam would have to tab/slot into a cross member to keep the I from becoming an I. LIKE IKEA FURNITURE

    Here is a article VAGUELY describing it in boats.
    I was going to include link in my original post but didn't want to scare contributors away with my novel.
    here is a link to pages 161, 163 and 164 of Boatbuilding with Aluminum By Stephen F. Pollard... however it is not comprehensive enough to duplicate the method. ...and i believe newer self jigging systems may avoid construction platforms and need only a level surface and the deck or deck framing is used as the platform. (but i want photos and info on either method if folks have um)

    Any info is appreciated.
    Ultimately i would like to be able to reproduce the method, if anyone knows what resource to use that would be great.
    A picture is worth 1000 words to me. If anyone has photos of a project that used this system please post um or PM me for an email.

    Much appreciated,
     
    Last edited: Apr 1, 2009
  4. bistros

    bistros Previous Member

    On a much smaller scale this method is used in plywood dinghies.

    Called "Stitch & Tape", precut plywood panels are shipped in a flat pack and are assembled by the purchaser. Each panel is "stitched" together by wire on matching edges, which by nature allows one dimensional curves to be created in each panel. Once all the panels are together, the boat "self aligns" to relieve stress, resulting in a square and true boat (if designed and cut right).

    Once the boat is "aligned" the individual seams are epoxied (or whatever resin) with a fillet and then taped with fibreglass (or whatever). When the inside joints are taped, the stitches are removed and the outside joints are epoxied and taped.

    The resulting boats can be beautiful with well developed curves.

    I would suspect the same thing true on a large scale - although panels are shipped flat, on assembly they devleop the designer's desired curve as they are welded in place.

    Cheers,

    --
    Bill
     
  5. bhnautika
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    bhnautika Senior Member

  6. yacht371
    Joined: Aug 2005
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    yacht371 Yacht Designer

    Self jigging boats

    I have designed a number of small (10 meter and under) power and sailing craft which were self jigging. All the parts were created in Autoship and Autostructure, and exported to autocad files for cutting.

    The bottom framing was of an egg crate design, with flat plate longitudinal bulkheads that interlock via slots in the transverse web frames/floors.

    The boats were all developed surface boats and went together perfectly. Autoship has a developed surface type and can flatten the plating.
    [​IMG]
     
  7. cadmus
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    cadmus da boom hit'um 1ce 2often

    yacht371 originally posted a photo. http://www.aviadesign.com/mk10struct.jpg It has expired or a server went down or something. So i am reposting it as i wish to refer to it later.
    thanks yacht371
    [​IMG]
     
  8. cadmus
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    cadmus da boom hit'um 1ce 2often

    Thanks Bill, Yes my family used to build "stitch and glue" or "stitch and tape" kayaks. I think the Origami folks often refer to "stitch and weld" as a word play on that technique. I think that might be what the Van De Standt "QUICK ASSEMBLY METHOD" includes as no frames are used at first.
    Thanks bhnautika for that link.
     
  9. cadmus
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    cadmus da boom hit'um 1ce 2often

    Sorry for never finishing this thread. Thanks for the info and time everyone.

    There must be more to this than simply CNC milling some notches.

    No boat has a flat deck, no boat has a flat bulwark rail, most boats have a cabin that is not going to support the entire boat, how does one make a self jigged boat without building platforms and jigs to hold it in position? Doing so would make it non-self-jigging by definition. I like the idea of building on a flat floor with no jigs so i want to see this work.

    In the non-selfjiged boat i would take flat bar for a stinger, bend it to the shape of the hull and measure where the transverse frames sits, mark it. So when selfjigging I now can cut that bend out of a huge plate with a CNC water jet and also cut notches instead of measuring and marking. Or do i still want to bend that shape because cold working the metal increases strength? If the former, should i bump up the thickness? What are the rules?

    How does one modify the scantlings and dimensions to account for the material lost to make the tongue/groove notches? Or do we just over build everything in addition to the original design for instance in a ring frame with extruded flat bar longitudinals do we CNC mill what used to be extruded flatbar so it has a shape like this. Where tabs are just extra material.
    _/¯¯|__|¯¯\___________________/¯¯|__|¯¯\________


    _______________________________________________

    How much gap is left between said tabs and the notched frames and the notches in the frames and the stinger I drew above? Are there rules to follow in regards to this? Can i temporarily shim the play in these gaps during welding?

    When during the 'lego' building do i start tack welding those notched joints. When do I stop tacking and start welding?

    If I am looking down on an egg crate shaped frame I see squares (right angles). I can easily change those squares to diamonds (not right angles) with a little bump. Is anything added at a non-right degree to ensure it is plum? I assume some longitudinals (on the hull, that are curved) will do this, is anything else used?

    yacht371, in your boat that image you posted I see a chine bar AKA planning strake. Did you use those planning strakes to jig or set the adjacent skin plating? If yes, in traditional layout building wouldn’t the ring frame be scalped to avoid contact at that joint?
    We never see planning strakes on sailboats.
    How is the skin self-jigged? Or is it not?
    It seems if we typically scallop frames to never touch skin plate at the weld it would be difficult to jig the skin plate. Please expand on this.
    How would those TIN triangles mentioned above be self-jigged?

    I could come up with a hundreds of ways to jig with little tabs+notches and that means there are thousands of ways. Some one must have summarized what worked what didn’t. Is there a book or journal article(s) that explains how one adjusts an existing design (ring frame with longitudinal stringers or longitudinal bracing on a heavy keel boat) to a self jigging build? Do i change scant lings? Do i change dimensions?
     
  10. BATAAN
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    BATAAN Senior Member

    Many years ago at a boat co-op in California I was walking by when a truck was unloading a load of steel.
    The prospective boatbuilder had patterns from a Canadian designer which he called Origami Boatbuilding I think. He transferred to the steel, neatly cut out 'darts' here and there, applied pulling eyes and a chain come alongs and sprung the bottom into a nice canoe form with a round bilge becoming a chine.
    The whole thing was jacked and pulled until it was straight and proper, then topsides added, inside stringers welded into crucial positions and a deck put on. What REALLY got my attention is all this took less than three weeks. The thick fin keel was a steel box structure full of cement and lead and added at the end.
    Here's a link to some newer stuff.
    http://www.freewebs.com/origamiboats/
     
  11. BATAAN
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    BATAAN Senior Member

    Try this out of paper and tape, any size.
     

    Attached Files:

  12. cadmus
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    cadmus da boom hit'um 1ce 2often

    YEAH. That is how Brent Swain builds boats. Very creative.
    I purchased Alex Christie's DVD many years ago that runs you through the "origami"process.
    Here is his page:
    http://www.freewebs.com/origamiboats/
    Even if you are uninterested in ever building this type of boat it is worth watching. In very limited time Brent bends a boat out of a sheet of steel with a few comalongs, a stick welder and a torch. Many threads on this site about orgami boats.

    But by "self jigging" i am not referring to origami style.

    By "self jigging" I am referring to a process where the traditional framing is built to be self jigging. It all fits together so you don't have to measure. Then skin plate is put on and I am told that is jigged as well but this is an enigma to me. From what several told me it allows one to use TINs rather than long chines because it reduces builder error. Traditional sequence of frame then skin, unlike Brent's orgami and Van de standt's quick build methods. (But i may be wrong)

    It probably is as simple as CNC water jetting out all your parts and adding little notches so you don't have to measure. But how is skin plating jigged?
     
  13. cadmus
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    cadmus da boom hit'um 1ce 2often

    I realize now that the pdf files i linked to many years ago are gone. It looks like Tata bought Corus.
    I found one of the files but it is not overly informative. Just advertising.
     

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  14. BATAAN
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    BATAAN Senior Member

    At the ILM Star Wars model shop we built quite a few ships and other things with a technique of designing a tab-together 'kit' on the computer in Rhino, laser-cutting a small scale 'proof' model from 1/8" ply to see it it works....
    Then cutting the larger frame from 1/2" ply and making the ship/spaceship/whatever.
    The first photo is the proof model for a Pirates of the Caribbean Chinese Junk on the bench.
    It seems the same process could be done with aluminum or steel and water jet or plasma cutting.
    The secret would be do a small proof model first I think.
    The other photos are all the 'same' 18th century ship, but in 1/12, 1/6, and 1/3 scales.
    The 1/3 scale is a deck section being built for a pyro shot (explosives), the 1/6 is the big one in background, and 1/12 is on stage being filmed. They are all made from the same computer file and a laser cutter for the frame.
     

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  15. cadmus
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    cadmus da boom hit'um 1ce 2often

    Ha ha ha, a SCALE REPLICATE TENDER!!!! ;)

    good idea
     
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