The purpose of this project is to design and mass-produce kits for a floating tiny house that can sail. It combines high-tech modeling and fabrication and low-tech assembly that can be carried out DIY-style on a riverbank or a beach. This boat is a 3-bedroom with a kitchen, a sauna and a dining room. The deck is big enough to throw dance parties. It can be used as a river boat, a canal boat or even a beach house. Oh, and it's rugged and stable enough to take out on the ocean. Kits will start at around $50k (USD). The design has been tested in simulation and prototype; full-scale production will begin next year.

Friday, December 2, 2016

It sails!

I finally found time to finish building the 1:12 model and outfitting it with sails and radio controls. Yesterday I sailed it around the marina, and I liked the results. It is fast and nimble on all points of sail, doesn’t leave a wake, and is very stiff. The shape of the bow provides for clean entry and little resistance. I didn’t notice any strange tendencies at all. Here is a video of QUIDNON sailing upwind in what for a 3-foot boat amounts to too much wind and quite a bit of chop, overcanvassed, with minimal heeling and good balance, and short-tacking successfully.


I might do a few more towing and stability tests, to verify hull speed and initial stability angle, but we already have these numbers from the hydrostatic and hydrodynamic analysis. I don’t expect any surprises, and so there probably won’t be anything to report. I am quite happy with how boring this design has been—doing everything it’s supposed to—and I am glad that the phase of playing with models is over. I am a serious person, and I find model sailboats to be silly. They are part of due diligence, but I won’t be taking them up as a hobby.

That said, the model-building process has been incredibly useful in three separate ways.

First, I had a chance to verify our technique for joining the plywood pieces using box joins and locking tabs and slots. I did find a few problems, three of them significant. We are changing the design in light of what I discovered, and will do another test at the 1:12 scale just to make sure we got it right this time before committing to a full-scale build.

One problem had to do with the curves at the bow: the plywood panels that make up the sides and the bottom as they come together to a point at the bow cannot be cold-molded and will need to be steam-bent, which is what I did.

Another problem came up while fitting the sheer strips—the long strips with the deadlights that run all around the boat just under the deck. It is not enough to secure them in place by locking them to tabs, because that produces a scalloped profile with many small gaps. Instead, they have to be pulled into place, by applying force to them at the transom. We will design jigs for steam-bending and for sheer strip-pulling.

Also, it turned out that while box joins with a rectangular toothed profile work fine for straight segments, for curved segments the teeth have to be trapezoidal rather than rectangular, with the angle of the sides of the trapezoids proportional to the angle of curvature. This turned out to be a problem when fitting the bottom to the sides.

We also had the problem of too much joinery—too many tabs and slots. Since they are free (the slots cost something in terms of the extra machine time it takes to mill them) we used a lot of them. It turns out that too much joinery is as bad as not enough, and will now work to find a happy medium, using the minimum of joinery that still allows the entire structure to be self-aligning and self-supporting.

Another major problem I was able to solve is how to eliminate virtually all finishing work on the interior of the hull. This should make construction go much faster by eliminating interior painting. The plywood panels will be treated with penetrating epoxy prior to milling parts out of them. Interior-facing surfaces will also be sanded, primed, sanded again, and painted with very durable two-part polyurethane paint, providing a surface almost as hard as a laminate. Exterior-facing surfaces will only be sealed with epoxy, to make them waterproof, since they will receive a coat of fiberglass prior to fairing and painting. The edges of the milled panels will be left unfinished, since they will be saturated with epoxy and filleted as part of the assembly process. Where the joint is exposed, it will then be dressed up with hardwood trim, while everywhere else, such as inside lockers, it will be left as is.

Lastly, I completely reworked the sail plan. The initial sail plan was based on Hassler & McLeod's Practical Junk Rig. They modified the original Chinese design, in which the entire sail is made up of fan-shaped panels, and replaced all but the top panels with rectangular ones, claiming that they stack more tidily and don't make much difference otherwise. After thinking about this quite a bit, I have come believe that they are wrong. In the original Chinese design, each fan-shaped panel forms a conic section, and is essentially a Lateen sail, which makes an excellent, efficient airfoil when cut as a perfectly flat piece of fabric. Lateen sails can sail very close to the wind. Keep in mind that the ability to sail to windward took a long time to make it all the way to Europe. The Chinese had this ability for centuries, using their traditional Junk sails. In other parts of the east, dhows used Lateen sails to the same effect. Only when Arab raiders started catching and looting European ships using Lateen-rigged corsairs did the Europeans look up and take note. But this wasn’t enough to make them abandon their backward square-rigged ships, which are terribly unwieldy and can barely move to windward at all.

But what Hassler and McLeod appear to have done in making the panels of the Junk sail rectangular is change their shape from a Lateen sail to square sail, and square sails are quite terrible upwind, tacking through no better than 60º. In theory, an airfoil can still be formed using the flex of the battens, but there are two problems with this: first, the battens flex more in stronger winds, which is the opposite of what’s needed, because the stronger the wind the flatter the sail needs to be; second, the battens flex asymmetrically depending on the tack, because on one tack the mast gets in the way.

To compensate, some people have recently decided to add camber, or “belly,” to rectangular sail panels. That was my original plan, which I thought was state of the art with regard to Junk sails. I was wrong; state of the art with regard to Junk sails is centuries-old. After I realized this, I designed a fan sail, which, as I have demonstrated yesterday, works remarkably well to windward. Here's my recipe. There are 5 panels, all fan-shaped, and 6 spars. Starting at the bottom, there is a boom, 4 battens and a gaff. All the panels are exactly the same in height at the luff and taller at the leach. The boom is horizontal, while each spar going up is angled 8º more than the previous spar, adding up to a 40º angle for the gaff.

At this point, we are able to declare QUIDNON’s design to be proven, in both digital and analog forms. It handles well under sail and motor, it is stable, stiff and steady, and, based on feedback from all the passers-by at the marina, it is pleasant to look at. We will now work on pushing the design to completion, since all that remains to work out is a very large number of relatively minor details.

23 comments:

  1. Wow! That thing sure did short tack quick!

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    1. To tell you the truth, I was quite surprised by its windward performance. There is usually some amount of fussing required to make a boat go to windward well. Here, you just sheet in both sails, steer a bit to leeward, and off it goes.

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  2. Nice work, Dmitry--you have one very sweet-looking vessel, indeed. How was your model loaded during the trial? Have you tried it in a fully loaded simulation trial yet? Or in an intentionally overloaded condition? How does it handle in a jibe maneuver?
    Thanks again for the virtual design 'trip'. I'm enjoying it immensely.
    With great respect,,,locojhon

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    1. The loading was based on our design ballast. I filled the water tanks with plaster of Paris to simulate water ballast and used some actual chain in the chain locker to simulate solid ballast. It drew just over 1", as it was supposed to. We've done various loading simulations in software, so there's no need to re-verify that. The jibes are the usual soft jibes because it's a Junk rig. Even a hard jibe in a lot of wind is pretty much a non-event. There is no gooseneck to break.

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  3. I guess my only question is, does it sail away from a downed helmsman?

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    1. No, I don't think so, unless it's on autohelm. If a helmsman goes overboard (which is very hard to do) the boat would just get into stays and float slowly to leeward.

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    2. Good trait. I actually sort of regretted the question as soon as I asked it, since it really only matter much on smaller, one person boats. It popped into my head since that's the kind of sailing I've always done, Lightening class having been my biggest boat.

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  4. Good news on the conical section research and testing. Who wants to design in and build those baggy square sections? My two self-made chinese lugsails were flat cut and so easy to sew up (relatively anyway.... sailmaking is hard work and literally a big pain in the back). The first one was a experiment with the lower 2 panels Hasler style and then rounded from there, as you have done, from the boom. At 435 ft. sqr. and made of polytarp it behaved well. I only replaced it since it was so huge and went down to a 335 ft. sqr. pure Hasler geometry sail (of Top Gun material per Tom Colvins suggestion). It could have been my batten material but this sail did not perform as well and was poorer to windward. But good news on the traditional fan shaped sail working just fine. Screw having to sew up 5-7 individual sections, all with belly, and then joining them all up. Want to REALLY go simplistic? Stake out the sail battens on the ground in the pattern desired, lace the boltrope along the perimeter, and unfold a big 20X40 polytarp on it, cut 6" over the boltrope all around, then trim and sew that to the boltrope (2 married couples and beer works well for this). Punch grommet holes and lace it to the skeleton. Works.... how I did my original 435 footer. Lastly.... the fan shaped sail just LOOKS better too. Colvins choice too but maybe also why he used a euphroe and all the extra spaghetti since the rear curve might bind the Hasler style sheets coming about. Allows the sails to be grouped tighter together too. It's ALL fun. Fair winds and good tides.

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    1. Hi Bob, good to have somebody "on board" who's actually built and sailed with a Junk rig. It's been a voyage of discovery for me so far. How good my design is to windward was a big surprise.

      For the full-scale build I initially specified a stitched sail with spars made of square aluminum channel to starboard and thin aluminum bar to port, riveted together with aluminum pop rivets every few inches and through-bolted together at the end of each spar. This would be stiff and light-weight. For cloth, a good choice for longevity would be Sunbrella, but working on the model I realized that some of the heavier-weight laminated rip-stop nylon would work very well too. The technique would involve finding a level spot big enough to unroll everything, glue the strips of fabric together, cut out the perimeter, then roll it up into a scroll across its width and feed it through a walking foot sewing machine going over each seam. Sew in bolt ropes, then lay it out and do the riveting. Roll it into a scroll again across its height, move it on board, and mount the parrels while winching it up the mast. Attach the rigging and go sailing. Does that sound about right?

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    2. Yes, overall logical and the way I mounted my own sails and I think the way Colvin does it too. Mount the sail and attach the sheet (or sheetlets if going the Colvin route) and fine tuning bits. I'd add that abrasion resistance in the fabric is really nice to have. Colvin specified Top Gun material and I found it too stiff and heavy on my 335 footer but it was really tough for abrasions. Dave Z. went with Top Notch and it is also tough but a bit lighter than TGun ( I STILL have a roll of this left it was a great price as "2nds" material which is slight blemishes). Hard to argue with regular sailcloth though for weight. Through bolted battens make some sense but I think they'd eventually abrade no matter what and wear along the batten length. Yet another reason to go traditional and sew in batten reinforcement patches. A pain but worth it IMHO. Then one can go with a batten just on one side. I played with 2" thick wall PVC pipe with wood cores in the aft 60%: trying to get a airfoil shape overall. Again, IMHO, not worth the effort. I feel the same about hinged battens. While sewing up your vertical seams if the sail is rolled up as a whole I'd make sure sufficient room exists to get the portion of the roll between needle and arm of the machine through so that it will feed. Personally I did my 335 footer a vertical panel at a time and avoided this, per Colvins book and method. Colvins book is worth 10X it's cost and comes as a mere 8.5X11 loose leaf bound book but his chapter on actually how to gather the material around the machine, feed it efficiently, etc. is priceless. He spells it out carefully and in detail and I'd have had to spend a long time figuring all that out on my own and probably not without major jackups. Good chapter on rigging and really good chapter on actually sailing a lug rigged vessel. Looking back on his accounts of how his particular boats pointed so well I think you are right about the fanned aft curve. His boats also had long straight keels and a deep biting forefoot for tracking but the rig style probably made a LOT of difference too. Lastly, didn't remember the fanned style fronted on a web site but it is the Reddish method with classic curve. I saved all the details if you can't find it now on the web and are interested. I made a little mizzen this way, of polytarp, and it was beautiful. Best wishes and good times ahead putting it all together. Inspirational to a lot of folks probably.

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    3. Oh yeah.... Colvins 33' "Lazy Lug" sharpie schooner, with two lug sails, is drawm out on his site. If he intuitively felt this vessel would do well with two fanned sails and no keel then that speaks volumes about that sails geometry as well.

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    4. Sorry for running on here. Reddish sail info here:
      http://www.thecheappages.com/junk/tutorial.html#Reddish

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    5. Bob Goad turned us on to TopNotch as sail material and we love it! It's polyester 'awning' material with a soft, beautiful hand. It's stood up well in AK (not much UV exposure, but it has a good rep). Relatively inexpensive and now comes in two weights. We went with the heavy (11oz), first round, thinking stormsails, and no complaints. Trying 9oz this round since trying camber.

      Another recent polyester that's looking good is WeatherMax. Cheaper yet. The hand is more like sailcloth, but basket weave gives it a bit of stretch. We built a sail (not yet tested) with this and like the material.

      Both are thread-coated for UV and water resistance. So no film. Cant tell they're coated by look or feel.

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  5. Congratulations! It looks fantastic. Instantly it made me think about Moitessier's; Tamata and the Alliance and Joshua Slocum before Bernard - dedicated, precise, devoted to getting it right. Will just put in an order for Shrinking the Technosphere. Thank you. As two former sailors we look forward to increasing our 'autonomy, self sufficiency and freedom' sailing way out here on the oceans of eastern Washington.

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  6. Beautiful! I find myself having Quidnon daydreams these days.

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    1. Yes, I want my damn boat already! But we still have problems to solve... Patience, patience...

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  7. I think you're right on with conic vs cylindric sections. Can add Pacific Crab Claw to Lateen.

    Even Hassler and McCloud agree... they chose cylindrical sections for other reasons than efficiency and saw it as a compromise. Double sheeting eliminates the advantage traded against efficiency.

    One point, though... cotton JR tends to develop some camber naturally in short order through stretch, and western hi-modulus (low stretch) JR rigs of any stripe have been working to catch up. Might be a little of each involved?

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    1. We'll have to see what's the least expensive and best solution as far as sailcloth. For light use (short-distance seasonal migrations, such as from Boston Harbor to Salem or Hull or Quincy for the summer) rip-stop nylon of the lightest weight would work. For sailing south for the winter, Sunbrella might work well. Sunbrella actually shrinks, but with a bit of heavy weather sailing it should get sufficiently baggy.

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  8. Interesting boat...Are you familiar with the work of Marine architect and designer Phil Bolger? He did a lot of designs for flat bottomed Sharpies, Scows, etc. One sail he really liked was the Dipping Lug. It is very good to the windward, but simple in rig. It's chief disadvantage is in short tacks. Most sailors motor in those situations anyway. For his own motor sailor, he built a flat bottomed double ender with a standing lug sailing rig that folded flat on deck. He had a low powered diesel that he used a lot, only sailing when he felt like it.He published a bunch of books on his designs. They are quite an education in what works. He is very close to your thinking. He's worked out many of the issues you are dealing with. Keep in mind that design is conservative for a reason. Too many changes make for unforeseeable outcomes.

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    1. The lineage of QUIDNON starts with Phil Bolger, then on to Matt Leyden's Paradox (that's where the chine runners came from), then on to Chris Morejohn's Hogfish (which I lived aboard and sailed all over for a few years). An infusion of good ideas came from Dave Zeiger's Triloboats. This design is basically a sharpie hull with an entirely new bow design (which was my idea). It is like a scow, but it is really an abbreviated sharpie bow, with the sharp point removed. This has allowed to increase the beam by at least a third without sacrificing much performance. So, yes, Bolger is the initial inspiration behind all of these developments, but we have gone far beyond him. His designs are still fun to look at, though, although I wouldn't consider building one.

      This design will use a double-sheeted Chinese Junk rig, with all panels fanned out rather than rectangular à la Hassler & McLeod. It points well and short-tacks nicely, since the rig is self-tending. It can also be jybed without touching the sheets except in heavy weather, and can be reefed down to just one panel without having to go up to the masts.

      Yes, design has to be conservative, or it becomes life-threatening in a big hurry. That's why this design project is taking more than two years. Good ideas take a long time coalesce into a design. This one has had its share of false starts and dead ends, but plenty of time to think and a bit of experimentation can overcome all that.

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  9. Unable to view the video, using Android browser, Chrome, Firefox, and Puffin.

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