Origami steel yacht construction

Discussion in 'Metal Boat Building' started by origamiboats, Nov 30, 2001.

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  1. origamiboats
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    origamiboats Junior Member

    If anyone is interested in an unusual steel boatbuilding method, please have a look at my yahoo group site called "origamiboats". I'd like to know what you think.

    The boatbuilding technique, which yields a longitudinally stiffened steel hull in quite a short time (a few weeks for the bare hull in some instances), has been around for many years, but most popular on the BC coast (Canada). Some have been built in Europe, and examples of the type have cruised far and wide.

    Myself, I am soon to start construction on a 40 footer, which is one of Brent Swain's new designs, representing a world-class cruiser with ample room for familes. His most popular design to date has been the 36 footer.

    Alex Christie
     
  2. Stephen Ditmore
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    Stephen Ditmore Senior Member

    Your web site

    What I'm able to see is suggestive of an interesting method, but I have a gripe with your web site. I don't like this business of having to register. Why should that be necessary? If it is, I think you should explain why, and how you plan to use any information that I should volunteer.
     
  3. Stephen Ditmore
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    Stephen Ditmore Senior Member

  4. Stephen Ditmore
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    Stephen Ditmore Senior Member

  5. Scott
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    Scott Junior Member

    Very Interesting. I am glad you pointed this out. I stumbled upon the origami group a while back but I didn't make it past the first page because I wasn't sure I wanted to sign up with yahoo either.

    It's like stich & glue for steel. And metal is so much more regular than wood, it makes a lot a sense.

    I wonder how accurate and how fair the hull is compared to a traditionally built boat. My first thought was that you would tend to get some distortions when building it, and it would be a lot of guess work to get rid of them. But maybe not.

    I also wonder about handling and bending material that large. The Photos make it look easy, but I would think it would require a lot of extra bracing, not to mention muscle, to get it into shape. Is this really as easy as it looks?
     
  6. Stephen Ditmore
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    Stephen Ditmore Senior Member

    First off, I apologize for the .zip file. I need to follow my own advice and get Debabelizer or Photoshop so I can create .jpg or .gif files. The .zip file contains a .bmp file showing how one might go about conically developing a hull shape for origami construction.

    Having established that an Origami hull is, or can be, properly "developable," why the restriction that it's for boats under 40 feet (see http://www.boatdesign.net/forums/showthread.php?threadid=249)? Are you just saying that boats over 40' may need additional transverse frames?
     

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  7. origamiboats
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    origamiboats Junior Member

    fairness of origami hulls, etc

    Hi all,

    Thanks for alerting me to the responses here, Stephen, as I had not looked here for awhile, and had no idea of the activity happening here!

    I'll attempt to answer a few questions as well as I can:

    Registration on yahoo group: In the same way people register on this forum, I set it up this way in order to keep a lid on spam and viral attacks from anonymous e-mailers. I don't have access to any information from the registrant, since it is Yahoo which hosts to group's space.

    Fairness: The hulls pull together in a fair curve simply because there are no transverse frames welded to the skin to distort it from a) heat distortion and b) thickening the hull where there frame would be welded on, making the skin material non-uniform. This means that the full length (31' to 40') piece of steel for each side (each side is built on its own initially) acts as a very long "batten" (see "building sequence" in the photos section of the group). It is a material of uniform consistency, so will bend into a mathematically perfect curve. For an example of this, take any long stiff length of material such as an aluminum ruler, a wooden batten, or even a strip of plexiglass. Bending it into a curve, you'll see no humps and hollows. Once the hull is welded together, there is no need to do any fairing with putties the way traditional steel boats are.

    The use of large pieces of steel for each side saves a lot of welding, which in turn saves a lot of distortion from welding heat.

    The attached photo of Moonraven, a 36 footer do Swain's design in Comox, BC, shows how fair the hull can be. I'm not sure if it is the best picture to show my point, but if you look along the side of the hull, you can see no ripples or distortions in the reflective surface. This hull was not faired with anything other than paint. Brent has mentioned in his book that even if you do see a small amount of unfairness after the first paint job (the human eye can detect unfairness to a very high degree), just wait until the next time you paint. He cautions that before attacking a hull with epoxy fairing compounds as is commonly done on steel boats, the owner should hold off. Why? In most cases a quick sanding in preparation for painting will remove the unfairness you may have detected, because the unfairness is more often only as unfair as the thickness of your paint layers. In this way, the fairing is "automatic" and you won't be chasing shadows -- sometimes any attempt to fair can end up making a real hash of it. So let the paint do the job. Anything left after that can then be focussed on and attended to, though it is unlikely this would be needed to any high degree on an origami boat.

    Ease of bending steel: The longer the piece, the easier it is to bend, since the curve is quite flat. A 36 foot piece of steel is quite floppy, actually, and does most of its curving without much need for encouragement. Even an 8 foot bar of 3/16th inch steel can be bent by hand around a fixed object quite easily. Brent Swain, the designer, has found through long experience that even a cheap come-a-long has the power to pull the steel into shape, and this works even when pulling the hull skin around the transom, which is quite a tight curve. He does recommend spot welding the nuts to the bolts on the come-a-long as a safety measure, however (that way the nut can't undo itself over time).

    Size limits: There isn't technically really a size limit on building these boats (I've heard of a 50 foot aluminum being built up northern Vancouver Island), but there is a practical limit to how big of a piece the builder would like to work with. Interestingly, this corresponds nicely to the practical limit for each boat in terms of use and crew. The 31 footer can be built by one person, and can easily be solo handled; the 36 footer is easier for two to build, and is ideal for two to sail; the 40 is a bigger affair, and I'll be taking my family along (though it should be easily handled by two). Anything bigger than that is bound to be more taxing upon the builder, both during the building process and in use. Brent's message of simplicity is to build only the size you need. Anyone who has spent time maintaining any vessel of any material will know what I mean!

    To date, the sizes up to 36' have been built without the aid of cranes and expensive handling equipment. The 36' foot half-shell (ie half of a hull split down the centreline) can be moved about a yard and positioned for welding to the other half simply by having one person at each end rocking it back and forth and "walking" it into position. For the 40 footer, this might not be as easy, though the piece could then be skidded on pieces of wood by attaching a line to a truck.

    I think this building system does work best with moderate beam hulls. If you are going for a very wide hull, then perhaps all you'd need to do is work in tranverse stiffening through the use and positioning of more internal bulkheads (not frames) of plywood bolted to tabs on the longitudinals. Because there is already substantial longitudinal stiffening on the hull skin, there is no need to weld tranvserse members to it. Doing so would only add un-needed weight and distort the hull skin. I'd advise consulting with someone fully in the know before doing it, however. Brent Swain's boats reflect his philosophy of moderation in all things, and he has seen no need to push the design to extremes.

    Meta of France has done some boats in aluminum of wide beam using very thick hull skins and no stiffening at all welded to it. These are slightly different in construction to Brent's boats, but they are truly frameless, and make use of the internal bulkheads.

    Hope that answered some questions, feel free to ask more if further clarifcation is desired.

    Regards,

    Alex Christie

    Origamiboats
    http://groups.yahoo.com/group/origamiboats
     

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  8. Stephen Ditmore
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    Stephen Ditmore Senior Member

    Alex, you seem to be a great resource for boatbuilders interested in this method; thank you for your time. I wonder how the scantlings that you're using stack up against ABS guidelines and other accepted norms for steel hull construction, but I agree that the Swain designs look good.

    I'm attaching a second possible scheme for developing an Origami hull, but I think anyone interested in building one of these boats would be foolish not to contact Brent Swain and Alex Christie and benefit from their experience.
     

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  9. origamiboats
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    origamiboats Junior Member

    Origami method of Sail-Tech

    Stephen asked me earlier if the method of metal boat construction as used by Sail-Tech seen at http://www.sailtechdesign.com/artic...uisingworld.pdf is the same of that used for the Swain origami boats. I once spoke with a fellow named Gunther at Sail-tech, and he admitted that the photo I had been looking at on their original website was indeed a Brent Swain design in steel. They have since that time used aluminum, and are building larger (over 40) boats.

    I have photos of a Swain 36 built in aluminum which I'll scan and post next, and it shows that you can build the hulls using the jigless method Swain has developed. However, it may be that Sail-tech is using a jig for building the larger boats in order to support the aluminum in the right shape before welding. I can only conjecture that this puts less stress on the initial tack-welds that are used to hold the hull pieces together initially before the complete run is welded. This would make sense in aluminum, since the weld is always weaker than the surrounding metal.

    Alex Christie
     
  10. origamiboats
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    origamiboats Junior Member

    aluminum origami hull aft portion

    For your interest, here is an aft shot of an aluminum origami 36 footer currently residing in Nanaimo, BC awaiting outfitting in the owner's front yard. One interesting thing I have found regarding the building of these boats in urban settings is that they go together so fast the neighbors never have a chance to complain! One day some steel or aluminum is delivered, then a few weeks go by and there is a hull in one piece, looking fair and boat-like, very ship-shape.

    Alex Christie
     

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  11. origamiboats
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    origamiboats Junior Member

    aluminum origami hull bow

    Here is a bow-shot of the same aluminum 36 foot hull. Note the very clean surface of the bow without cuts and weldments needed to attain a proper and pleasing shape.

    Alex Christie

    Origamiboats group site
    http://groups.yahoo.com/group/origamiboats
     

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  12. Stephen Ditmore
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    Stephen Ditmore Senior Member

    Alex, is there a way to build a watertight bulkhead in one of these boats? If not, do you recommend foam flotation, empty tanks, yachtsaver bags? I'm concerned that one of these boats could go down very fast if it blew out a seacock or somethihng.
     
  13. origamiboats
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    origamiboats Junior Member

    bulkheads and seacocks

    A member of the Origamiboast forum is currently building a 36 footer in Nanaimo, BC with a watertight forward bulkhead, so certainly it can be engineered. I have written him to ask if he'll respond on this forum. Conversely, you are welcome to post the same question on that forum. There are quite a few members on that board who have built their own boats and must have pondered the same question.

    In all but one (the aforementioned) of the origami yachts I have seen, they do not install watertight bulkheads. With watertight hatches as built to the designer's plans, the boat itself is the ultimate watertight bulkhead. There is an anecdote of one of the 36 footers running headlong into an un-lit barge in the middle of the night at 8 knots and suffering no ill effects. I believe its survival is no accident, but a result of the incredible strength of steel hulls. Properly welded, the steel hull and deck are "monolithic", with no one area weaker than the other. All parts interrelate to create an obect of high resistance to the stresses of impact.

    The seacock concerns aren't really an issue on these hulls. The designer has worked out a very good system for this. After deciding where to place your through-hull, you simply weld to the hull a short length of stainless pipe that has a threaded end, onto which you can install a stainless steel ball valve, the types which can be found in the scrap yards of pulp mills quite cheaply. These valves are made for high pressure and severe service in contact with corrosive liquids. Their duties as seacocks in a low pressure situation are minimal and without stress, so for a steel boat they are "over-engineered".

    I seem to recall the designer telling me once that you could indeed put enough foam into one of these boats to make it float after the unlikely event of holing, but you'd lose alot of interior space, as you would with a fibreglass boat, or any hull made of a non-bouyant material. Yachtsaver bags would take less space, if you don't mind the expense. I don't know of any origami boat builders who have opted for this, however.

    On another tack, a friend on the BC coast has designed and built a 39' composite wood/glass fast bluewater cruiser which is unsinkable. It is called "Timeless" and can be found on my other group site called Light Displacement Cruisers:
    http://groups.yahoo.com/group/lightdispcruisers . There are photos of the hull in the files section. Some purists in that forum took a dislike to that boat, but I know it to be a fine vessel more capable than most production boats of equal size. The forward section on that hull has a crash bulkhead ingeniously doubling as the back wall of the bow water tank. The hull can continue to float and sail even after having that part sheared off, and even if the bulkhead were broken, the hull would continue to float. Their head-on encounter with a hard object proved, however that their heavily built bow was already capable of withstanding a lot more than your average hull could take, so they haven't been able to test out their watertight bulkhead.

    While their hull is of a different material than an origami boat, it is similarly monolithic because of its composite structure. They utilise a very thick wood core with a heavy lay-up of fibreglass outside and inside. The lay-up wraps right around the deck edge and over the decks, creating a seamless structure, like a submarine. The fibreglass skin in this case is more than an abrasion-resistance device, it very much a real part of the hull and deck itself. Certainly interesting to ponder.

    Alex Christie
     
  14. Stephen Ditmore
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    Stephen Ditmore Senior Member

    I appreciate your thoughtful & informative response, Alex. Thanks!:)
     

  15. Scott
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    Scott Junior Member

    I should have thanked you also as I found this discussion very interesting. I didn't know this was possible before... one of those things that you get set of thinking there is one way to do things (frames first, then skin) and sometimes miss the other interesting options.

    I also just found a second reference to this method on this site: http://www.kilim.com.tr/ardali/bb-cont.htm#frameless

     
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