"Self-jigging" flatpack kit for metal hulls

[cadmus]

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_so..._DATASHEET.pdf
or also found here
http://www.corusservicecentres.com/f...aflet2page.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

[sharpii2]

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.

[cadmus]

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.
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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,

[bistros]

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

[bhnautika]

Cadmus have a look at Van De Stadt Design . http://www.stadtdesign.com/English/history11.htm

[yacht371]

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.