The Twelve Foot Yurt

The ten foot yurt has had a few outings in the past few years.  It worked well but I thought it could use a little more floor space in conditions where we wanted to use part of it as a kitchen. So I set to work on the design of a twelve foot version.

A twelve foot diameter, vs. a ten foot diameter would give this yurt 44 percent more floor space.  I decided to keep wall height the same so that I could re-use the existing wall lattice, needing only to add another 6 foot section of wall to bring the circumference up to 37 feet from 31 feet.  

I tried to figure out ways to re-use the existing roof parts, but that was not possible.  Still, re-using the existing wall parts and door cut down considerably on the total amount of work.

So on to some pictures.

Heres the sewing studio for the roof. I tried sewing the roof on the floor of the living room at first, but the large hunk of canvas kept colliding with various furniture.  Having the large flat area of our driveway to rassle the canvas was a big plus. The other thing I learned from the ten foot yurt was to soak the canvas in water and let it dry to shrink it before cutting and sewing it.  Shrinkage was mostly along the length of the canvas with very little across the width so trying to get a good fit without pre-shrinking the canvas would have been a challenge.

 This photo is of the trial assembly of the yurt in back of the shop. Looks good enough.

 What you are looking at here is the extension of the wall canvas joined to the existing wall canvas from the ten foot yurt.

 I also decided to add a skirt to the interior of the yurt to minimize the amount of sand blowing into the yurt in windy weather.

 And this is the tono or roof ring.  I made the roof poles a little over long so minor changes in length wouldnt have them pulling out of their sockets.

 Heres the twelve foot yurt pitched in front of the original 16 foot yurt.  Note the difference in roof pitch.  I wanted to experiment with a lower pitch on the twelve footer to keep interior volume down for easier heating.  The new pitch was 30 degrees vs. about 39 degrees for the 16 footer.  A lower roof also makes for easier setup of the roof.

 I also decided to make a door frame for the door cover, an upgrade from a simple flap that hung over the door but was a nuisance to go in and out of.  The assembly of the parts is tongue and groove for reasonable stability combined with ease of disassembly.

 Once I was done, I dragged all the yurt parts outside to weigh them.  Total weight about 198 pounds.  Not suitable for backpacking but OK for car camping.

And here, the yurt deployed in the Mojave National preserve.  We wanted an open roof for star viewing at night but rigged a table cloth for shade during the day.  

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Coaming

June 18, 2015
Attaching the coaming has become an obsession of sorts.  I want the coaming to go all around the cockpit and provide an aestheticly pleasing line as well as a functional drip control.

The method was to steam the 1/4" plywood and then bend.  I broke the first few pieces necessitating a trip to get more plywood $$.  Then, decided to soak the wood, wrap it in a towel and then bend one piece at a time.  When I tried to do two corners at once, things got dicey as the wood did not want to bend and took on a reverse curve inwards towards the boat.

Recipe - soak overnight, wrap in towel, steam for 40 minutes, bend VERY QUICKLY. It loses pliability within 5 minutes of being removed from the steam.  SUCCESS!

Pie

Overlap at centerline will be trimmed to flush and a decorative trim piece placed over it.  Coaming will get shaped and then molded to 3" wide in general (except 2.25 where the coaming is flush with the deck.

ces will be trimmed to shape this weekend.  With the trim going flush where the skipper sits, then rising again across the stern deck with enough clearance for the tiller.  Steam box set up could use more steam, but I got it done with patience (and a little perserverance).

The wires only served to make black stains of the wood,  use small blocks of wood to hold the work up off the bottom.  I did find the wires helpful to hold the door shut and make the box smaller or larger as needed.

Nice!  forty minutes of steaming and work fast!  Later on I placed a block of wood at the end on the right and bent it into place quickly.  This would be better with a helping hand!

Sheet rock screws work, but later on I put the screws into a plywood pad first, which creates a much smaller hole in the work. 

Work in progress. 

This works, but is a little anemic.  A larger pot, and larger hose would help a lot.  The box does retain the heat and steam with the wooden doors and towels placed over each end.  Dont use the wires to hold the work up, it stains the wood.  a few blocks of fir accomplish the same thing.

6-22-15
Coaming has been fitted and can be glued up tomorrow.  What a struggle as I miscut several pieces, cracked a few, and then put the scarphs on the wrong side of one plank.  But, it looks nice.  I still have not cut down the areas where I know I will need to hike out as it looks real nice at this point in time.  I dont have the heart to cut it where I know it will cut into my butt while sitting on the rail.  perhaps a seat cushion will do!  Thinking that I might use the boat, then make decisions for modifications.

6-26-15

It came out nice.  The only issue I had was where some paint lifted off the deck.  Primer is stuck well, but the top coat lifted from the primer where I had put down packing tape.  I am thinking that the tape sticks too well in the warmer weather, or perhaps I have used tape that was too good.  Gotta fill screw holes and sand, sand, sand.

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The Americas Cup

The Americas cup is one of those sailboat races that has been going on for a long time and happens again and again at various intervals.  Seeing as it involves large sailboats, only the very rich can compete, albeit with hired crews.  This year the race or part of the race is happening in San Francisco Bay on which I live and so the news about it reaches me.  I have nothing to offer on the merits of the race but it did happen that the Swedish race team is working out of an aircraft hangar close to my own modest boat shop and so on the way to work or going home from it, I see the boats that compete in the event.  So I want to offer some photos of the Swedish boats because I find the boats interesting.
By the way, I understand that the current crop of boats are a short version of what will be in the final competition.  And all the boats were built in New Zealand by the same builder to the same specs so that he race is about who has the best crew and not about who has the best boat.

 This is one of the two Swedish boats tied off to a buoy in the Seaplane Lagoon.  In the background, one of the maintenance hangars from the Naval Air Station days.

 The boats and the sails are moved in and out of the water by a crane.  They are not that heavy as boats go, around 3000 pounds. 

 Here is the boat itself, without its rig.  Dagger boards are in their retracted position.

 And the Americas Cup logo and Swedish flag.

 The boat has a wing and a jib.  The wing is symmetrical about the center plane unlike an airplane wing which is usually flatter on its bottom face.  

 And there are the Swedes, out on the bay doing their stuff with their support boats motoring behind them.

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Plastic kayaks Pros and Cons

Recently, a friend let me paddle his plastic kayak, a boat that he was quite fond of.  I never turn down an opportunity to try out other kayaks and so I got in this one and paddled away.  The boat looked very pretty with its white bottom and yellow top and was still new and shiny, but the bow seemed too blunt and pushed too much water, creating much noise in the process. It wasnt a flaw that you would be likely to notice just by looking at the boat, but it was readily apparent once you paddle it.
I reflected on this and came to the conclusion that I couldnt be the only person that noticed this problem with that boat.  But given that the manufacturer had already invested in a mold, he probably had to sell a certain number of boats before he could recover the cost of the mold.  Only after that point could he consider making a new mold.  The longer he held on to the old mold, the cheaper the cost per boat would be.
And that, in a nutshell is one of the major problem of mass produced boats.  The thing that makes mass produced boats cheap is that they involve a minimum of labor.  Make a mold, and once you have a mold, you can squirt plastic into it and out comes one shiny boat after another.  But the mass production is a good thing only if you have designed a good mold.  The manufacturer had better built a number of prototypes and tested them for good design before committing to a mold.
If users give the manufacturer feedback on design flaws, he really cant do much until his first mold is payed for. And this is more of an issue for small manufacturers who, lacking deep pockets need to pay as they go.
If you buy a custom boat from an experienced builder, you pay more than for a production boat, but you are also less likely to be a victim of design flaws.  I suspect the custom builder gets to build a lot more boats and gets a lot more design experience than the builder of production boats.  I might be wrong, of course, given that I dont really know what credentials production boat designers have or whether production boat manufacturers even have experienced designers on their teams or just hire consultants or copy someone elses designs.  If anyone knows, Id like to hear from them.

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Deck Hardware and sail report

July 20, 2015

Sorry for the lack of updates.  But, I wanted to go sailing this summer and decided to put the computer on hold in exchange for a full focus on finishing the boat.

Deck hardware was installed with backing blocks, and polysulphide sealant.  It is amazing how many little screws, washers, lock washers, bolts, and nuts are needed to install the cleats and blocks.  This necessitated no fewer than 5 trips to my local hardware store that has a very good selection of stainless steel hardware (amazingly out of $10 lockwashers).  The only tricky part was the installation of the centerboard downhaul and uphaul, as this was a new type of system I needed to learn as I went along.  In practice, it works well, but necessitated shaving down the aft part of the floorboards that serve as a platform up front so that the lines would run free.

I also needed to move the boat onto the trailer, which meant the 18 workskiff needed to come off.  Using levers and jacks, I was able to lift the 1000lb clamming skiff off the trailer and then slide the Core Sound 17 onto the trailer from the building form using old rugs to protect the finish.  

The CS17 fits perfectly.  

I still need to add the self-bailer, and the docking hardware, and oarlocks, but it was time to get out on the water and see how long it would take to rig and launch.  

30 minutes to step masts and rig.  could be 15 without mistakes. 

As you can see from the photo above, there was very little wind, but the boat moved along even with ghosting conditions.  

photos of the launch. 

https://www.flickr.com/photos/41024536@N02/sets/72157655720562508

July, 21,2015

Went out to Hopkinton State Park.  It was much better with winds 5-12kts.  The boat sails beautifully, and points very well.  I was very pleased with how easy the boat is to control and how well it responds to gusts.  I felt in control at all times throughout.  

Sorry, no photos, I had my hands full.  

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Plywood the other boat skin

One of my ongoing research areas is what to cover a skin on frame boat with other than industrial fabrics sealed with modern sealants.  Yes, there are animal skins, and I know that people have covered their boats with cow hides, but you see, we live in an industrial society and the imaginary scenario I am creating for myself is that the factories have shut down and one has to operate as boat builders of old did, that is, to find boat building materials in their immediate surroundings.
Perhaps we have to broaden our definition of skin on frame a bit and allow a boat where the skin is the main structural material and the frame is of secondary importance.  Enter the plywood boat.
In my case, not a boat exactly but a plywood pool punt.  The main idea was to not spend a lot of money.  The secondary idea was to provide a stable lounging platform for a pool in an environment that is too cold for swimming for most of the year.

Here is the punt under construction.  One sheet of plywood formed the bottom, another formed the sides.  Height of the sides was just a bit under 16 inches.  Early trials established that 16 inch sides were too high so I trimmed them down to 13. Perfect. The sheets of plywood are screwed to battens inside the punt for additional support.  Water proofing of the screw holes courtesy of 3M 5200. Water proofing of the seams was done with a layer of glass adhered by epoxy. 

Initial trials also established that the sides of the pool abraded the fiberglass that I sealed the seams with so I added some wooden bumpers at the corners and some skid rails at the bottom for dragging the punt in and out of the pool. Then a few coats of gray paint from a five gallon bucket that a friend was tossing away, or rather, giving away. And oh yes, we realize that the pool is greener than it should be. 

The same day we launched the new improved punt we also ran into a small futon and some quilts that a neighbor was discarding.  These are now lining the bottom of the punt.  Very comfortable and stable to boot for someone used to sitting in narrow kayaks.  Sometimes it is OK to trade speed for comfort.

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Why Build Your Own Kayak

A friend of mine recently posted a picture of a customized car from circa 1970 Houston, Texas.  What struck me about the photo was that the owner of the car clearly wasnt satisfied with the amount of chrome that designers back in Detroit were putting on cars at the time, so he took matters into his own hands and added chrome to a level that he felt was appropriate.

And this same sort of urge, not the urge for more chrome, but the urge for more cool is what led me to start building my own kayaks. It was not about money, it was simply the desire for a superior esthetic over what commercial manufacturers were capable of delivering. Others may disagree.  Many prefer the look of shiny plastic.  I prefer the cool of skin on frame.

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