Skin on Frame Housing the yurt gets a roof

Progress on the yurt continues.  Much of the progress is imperceptible to anyone but myself but the progress is there.  As it turns out, my initial suspicion that my first yurt would be a prototype for working the kinks out of the design turned out to be true. So let me share what Ive discovered so far.

 I got the crown on the central ring of the yurt.  I used some kayak rib stock, 1/4 inch by 3/4 inch white oak, socketed into the central ring and lashed together with tarred seine twine. The idea behind the crown is that it will be open under normal conditions but covered when it is raining or heat needs to be kept in the yurt.
Another discovery I made after the initial assembly of the yurt was that for the sake of getting a good setup it helped to trace a circle on the ground first before erecting the walls so that the walls would form a perfect circle.  The perfect circle is essential so that all the rafters are the same distance from the central ring.
I also discovered that I had much more wood in the central ring than I needed and so it was too heavy and difficult to get into position when no help was available. What I did to remedy the weight problem was to cut some of the extra wood away from the center of the ring.  It was way stronger than it needed to be. 

 The next step was to cut out some fabric for the roof.  It took me some time to work out the trigonometry for the roof cover shape, but I did it.  But I have learned to distrust theory and test with an actual life size cover.  The other reason for getting the cover in place was that a series of rain storms were coming into the area and that would be a good test to see how the cover would stand up to the wind.

Heres an inside shot of the cover.  The wind lifted it some and pushed it off center.  Part of the problem is that the shape of the cover is like a pie with a wedge cut out of it and the edges adjacent to the missing wedge get pulled together and glued or sewn resulting in the desired pyramidal shape.
The cover is made out of some sort of vinyl covered fabric that is used for advertising banners.  A friend gave me a bunch of these banners and I cut them up to fit the roof. The fabric has two problems.  One is that it is very heavy and the other is that it is very stiff.  The combination of weight and stiffness makes it very difficult to pull this stuff up on the roof.  The weight also works against its portability.
On the plus side, the cover survived the storm and did not get blown off.  I also discovered that once again, there is nothing like building something to test a design because until you do, its next to impossible to know what sort of problems the design has.  So far, none of the design elements have been complete failures but lots of them can use improvement.
The list so far.
The wall battens are slightly too flexible.  A bit more stiffness is advisable even at the expense of greater weight.
The skin is too stiff and heavy.  Lighter weight is advisable.
Other commitments have kept me away from the yurt, but the learning continues.  I will continue to post whenever there is progress or even when design ideas fail.

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Forward frame is fit!

After a couple of hours of trying to get this frame in place, i finally figured out how to do it.  i put blocks aft of the frame to keep it from slipping and a couple of strategically placed sheetrock screws.  Then, I put a marine battery on top to weight it against the bottom.  It looks pretty good at this point. 

Will let it sit overnight and then begin tabbing in place.  

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Yurt or Skin on Frame Portable Dwelling

I havent done much boat building lately since I have been busy working on a yurt.  Though this blog is supposed to be all about skin on frame boats, I thought it would be OK to indulge in some related skin on frame construction, namely, the yurt or portable dwelling.
The idea of building a yurt came to me after last years October camping trip.  We were pretty far south but at high elevation and so we encountered snow and cold nights at times.  We had an adequate tent and warm sleeping bags but the sun went down early each day and then stayed away for twelve hours so that once it got dark there was little to do but crawl into the bags and listen to books on our mp3 players.  Camp fires and eating are usually good camping entertainments, but most campsites have fire rings that keep the heat of the fire away from the camper and otherwise hamper what should be a good entertainment.  Likewise, cooking food when it is near freezing is possible but once the food is done, it gets cold in a hurry and then you have to clean up in the dark and cold.
So the idea of a tent that was big enough to stand up in and build a fire or set up a camp stove in and cook in and eat in, all in comfort and warmth wormed its way into my consciousness.  The idea of a tipi came to mind, but those require long poles and a lot of canvas and would add a lot of bulk to an already bulky camping load. So then I thought about yurts.  And as a little research showed, there were lots of articles on the topic on the internet. 
In addition, my neighbor, Tim Anderson had built a yurt and so I could use him as a technical adviser.  So off I went on the yurt adventure.  I quickly found out when doing the research that everyone builds yurts their own way and nobody seems to tell you much about general principles like how strong to make the walls or what the pitch of the roof should be, whether the thing will hold up to a snow load, heavy winds and so on.  And so I decided to build a prototype yurt that could sit behind the shop.  I would use it to work out the design details and once that was done, I would build a smaller more portable and lightweight yurt for camping.
So here goes with the photos.

 The target diameter of the yurt is 16 feet so I needed to construct 48 feet of wall.  Circumference of a circles is pi times diameter of the circle, remember?

Heres a closer up view of the wall with another semi-nomadic structure behind it.  Nomadic if movable by fork lift fits your definition of nomadic.  In any case, for the sake of convenience the wall of a yurt is usually constructed in sections so that each section is of a size that is easy to lift and not too wide to transport.

And heres a shot that tries to show the curvature of the lattice wall.  Hard to visualize this sort of thing until you actually build the wall.

Intersections of the wall slats are held together with clinched nails, that is nails whose tips are bent over and hammered down and buried in the wood.

Heres a view of the junction from the other side where the tip of the nail is buried in the slat.

And here is one section of the wall, all folded up into a 30 inch wide section.  When unfolded, this represents 24 feet of wall.

When the two sections of wall are joined as shown here (temporary joint made with clamps) the wall is complete.  And the 96 inch long slats at an angle make the wall 72 inches tall.

The other two ends of the two wall sections will get connected to a door frame, not yet built.  Note alternating colors of wood.  I had enough old redwood deck boards to make almost the whole wall but had to buy a few extra doug fir two by fours to top off the number.  The redwood was free and light.  The doug fir was about ten dollars total and stronger than the redwood but also heavier.  We will see how they hold up over time.
Stay tuned for door frame, roof and canvas cover yet to come.

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California Drought

California is in the third year of a drought.  I report on this only because I live in California.  I like where I live right now because as you know, I build kayaks and kayaks need water and the place where I live, Alameda an island in San Francisco Bay gives me ready access to the water.  But the water is salty and not suitable for drinking. In Alameda, water for drinking comes from reservoirs which store winter rain runoff. When winter rains are insufficient, water from the San Joaquin and Sacramento rivers is pumped into the reservoirs.

The picture above shows what California looks like right now to a climatologist.  The darker the color, the worse the drought.  As you can see, a good part of the state is in the chocolate condition.

Let us zoom out a bit for perspective.  Washington, Oregon, Idaho, Nevada, Utah, Arizona and New Mexico also have a bit of drought but nobody has as much chocolate colored drought as California.

The chart above puts names with the colors. Drought goes from Abnormally Dry to Moderate, then Severe, then Extreme and then Exceptional.  As the names indicate, California is having a drought that would not have been considered normal when the names for the severity of drought were made up.
We are told, furthermore, that in the past, Californian droughts have lasted from years to decades, maybe even centuries and nobody seems to know what sort of duration this particular drought will have.

Long term droughts are game changers.  The photo above is of a place in Camp Verde, Arizona called Montezumas Castle.  The people who built these dwellings apparently abandoned the area during a prolonged drought.  The people who lived there were primarily farmers, raising the usual southwestern crops, irrigated by the river that flowed at the base of their cliff dwelling.
The moral of the Camp Verde story seems to be that no matter how swell the place youre living in may be, if you dont have water, you go elsewhere.
So, even though this is strictly in the realm of speculation, prolonged drought in California could well depopulate the state significantly.  Californian climate refugees would move elsewhere. Farm workers would move back to the Spanish speaking parts of North America. North American cuisine would revert to what it was in the 50s, that is, lots of canned green beans in the winter and canned spinach and canned corn.  Vegetarianism would go back out of style.
The prime users of water in California are of course the farms and orchards that raise the 20 billion dollars worth of crops that are grown in Californias Central Valley.  If the Central Valley turned back to grasslands and oak savannah, perhaps some coastal cities could still survive on the water that was left over.  Who knows.  In the meantime, water use is being curtailed.  Lawns are going unwatered, trees are dying and so on. 

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The Education of the Self Taught Designer

A Rube Goldberg design.  The term "Rube Goldberg" has come to mean any overly complicated contraption.  I think Rube was drawing parodies of products produced in the gizmo enamored society that he lived in.

Someone once said that you cant design a thing that youve never built before.  Experience has taught me that this is true.  What that pronouncement means is that to design a thing, you know ahead of time how each design decision will affect the performance of the finished product.  The rub is that until you actually build a thing for the first time there is little chance that it will actually work.
You can of course go to a school where they teach you how to design stuff and you get the benefit of someone else telling you what works and what doesnt so you dont have to figure it out for yourself.
But as I recently observed with the business of designing kayak paddles,  theres nothing like building something that doesnt work to teach you why you should build things that work.  Building things that dont work draw the border on what is possible.  Stray outside that border and you get stuff that doesnt work.  Stay inside the border and you get stuff the works.
So mistakes and bad designs are important because they provide the designer with a better understanding why stuff that works works.  If everything worked then there wouldnt be a need for designers. Designers, good ones at least have a good mental map of the territory of what is possible and what isnt.  The more things the designer has actually built and failed at, the fewer bad designs he / she is likely to pass off on customers.

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Chairs Skin on Frame and Lashed

One of my readers sent me some photos of chairs made in Mexico by traditional means.

Full view of the chair.

Lashed construction holds the parts together

Lashings hold uprights to the bottom ring.

He writes in part,
I recently got back from a trip to Mexico visiting my wifes family. When down there we saw a style of furniture construction which reminded me of skin on frame, in that it involves multiple relatively poor quality pieces of lumber lashed together in a way that makes it both strong enough to do its job and is also very resilient to impacts. It seems to me that this chair and SOF (bicycle wheels as well) are so strong is because loads and impacts are dissipated by transferred them to multiple small, relatively weak, parts instead of concentrating them on one part that must be thus very strong. The type of furniture is called Equipale and was very common in the state of Jalisco. (I do not know if it is a regional style or a national one).
And Im adding some photos of two chairs of ours that were falling apart because the glue was coming undone. These were chairs where the parts were held together with glued dowels.  The glue failed and the dowels pulled out of their mortises one evening at dinner while a friend of ours was sitting on one of these chairs.  The dowels were still stuck on one end and drilling them out would have been tricky so I just reassembled the parts and lashed around the joints.  The chairs now have some movement in them since the lashings dont make completely rigid joints, but overall, they are hanging together.
This isnt skin on frame technology, but it is lashed and doweled construction where lashings take the place of glue or screws  to hold parts together.

Here I reenforced each doweled joint with a lashing.  Even if the glue fails, the joints will not pull apart.  The string lashings function like ligaments in animal joints.

Here, my lashings pull all the legs toward the center.  This approach is less work than lashing each joint individually. Now that I look at this photo, Im thinking that I should paint the lashing some color other than white.

Postscript: I first saw these two chairs at a neighbors yard sale.  I didnt care enough for them to buy them but picked up some lamps.  Next morning the chairs sat out in the alley next to his dumpster so I grabbed them.  Painted one red and the other one blue and reupholstered the seats in yellow vinyl. Subsequently painted the blue chair orange.  I believe the chairs now have a few more decades of life in them.

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Eastern Arctic Kayak Construction more frame photos

Yesterday I set up the frame of the EA kayak and gave it a second coat of linseed oil.  With the keelson blocked in and the deck upright, it is easier to see what the boat will look like when finished.  Supposedly, the finished boat will not trim with the waterline parallel to the keelson.  The keelson will in fact sit lower in the front than in back. But we will see. 

Nose forward view accentuates the upsweep of the deck forward of the cockpit.

View from the back shows the downward slope of the deck at the steern.

And one more view from a slightly lower angle.

At this point, I find myself wondering what this boat will turn into and how it will behave.  This is of course one of the compelling things about building a boat of a kind one has never built before.  Invariably, there will be some disappointments and in time, pleasant surprises as well.  Still, if nothing else, the curved lines of a boat are delightful to look at.

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