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Jumat, 30 Desember 2016

A little more painting

Its October, and with it have come the low grey clouds, rain, and cooler temperatures to usher it in. It was a beautiful day.

I got a little more painting done on the boat tonight... working on that center section I epoxied a few days ago. Its slow going, painting it with a brush. Hopefully Ill make some more progress on it tomorrow.




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Selasa, 27 Desember 2016

The Herons are Back

yes, the herons are back.  There they are out back of the shop on the other side of the fence that divides the federal land from that under the control of the city of Alameda.  A few years back, there were maybe five herons that used to hang out back of the shop.  This year there were twelve that I counted plus a few more hanging out in a Monterey Cypress just off to the right of this pictures edge.
And here we are zoomed in just a bit more on the great blues.  Off to the sides are Canadian geese also hanging out and choosing nesting sites.  I imagine it must be mating season.  Not sure, but the male herons might be the ones with the fancy Mohawks and the females the ones with the more slicked back look.
What a difference a fence makes.  On our side of the fence, nothing is going on bird-wise.  On the west side of the fence, birds are doing their bird thing.  Not that they spend much time thinking about the fence, but they do seem to realize that humans dont go on their side of the fence and so they go about their bird business which is eating and apparently this time of year, reproducing.  Hope it works out for them.
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Paddle Design Stability

In this post I want to focus on ways to design a paddle so it orients itself in the proper direction for paddling without a lot of effort on the part of the paddler. A paddle that requires a tight grip to keep it in control will sap the energy of the paddler and cause fatigue and diminished efficiency.
Not surprisingly, there is more than one way to make paddle orientation easier to control. I will examine three different ways all of which can be used in various combinations. I should also mention that the intended use of the paddle, whether it is meant for racing, cruising, surfing or rolling will have an impact on how it should best be held.
Most traditional paddles have oval or egg shaped looms with the longer dimension of the oval perpendicular to the face of the paddle blade. The oval shape makes it easier to keep the loom from twisting in the hand than a loom with a circular cross section.
A second way to keep the loom from twisting in the hands of the paddler is to hold the paddle at least partly by the root of the blade where it joins the loom. For instance, in a shouldered Greenland paddle, the index finger and the thumb circle the loom while the other fingers and the rest of the palm circle the root of the paddle blade. The flat part of the blade resting against the flat of the palm gives the paddle stability and keeps it from rotating in the hands of the paddler.
I thought at one time that it was only the Greenland paddles that were held this way, but there are some photos of Unangan (Aleut paddlers) that also show them holding their paddles so that at least part of their hand is on the root of the blade and part on the loom.
A third way to stabilize a paddle is to design it so that the paddle blade naturally wants to orient itself in the right direction when the paddler pulls on the loom. This trick only works for paddles that are asymmetrical, that is paddles that have a front face that is different from the back face. When you pull this kind of paddle through the water at some random angle, it will have one face that will naturally orient itself in the direction of travel while the other face orients itself away from the direction of travel. It is like a wind vane which if put sideways into the wind will turn its head into the wind and its tail out of the wind. Examples of this kind of paddle are the Unangan (Aleut) paddle and bent shaft paddles in which the face of the blade slightly trails the loom as the paddle is being pulled through the water.


In these two closeups of Unangan paddlers from the same boat, both paddlers are holding the paddles with the flat face toward the back.  The interesting thing with these paddles is that the weather vane effect would favor holding the paddles flat face toward the front but the shape of the paddle in the areas where paddlers held it also make the opposite orientation stable. The photo was no doubt posed and both paddlers are just holding the boat in position rather than paddling forward.  They may actually be paddling backward. So it is hard to tell whether this is the way they held their paddles when moving along, but regardless of what was happening when the picture was taken, it seems that the shape of the loom allows the paddle to be held in a stable manner regardless of orientation.
This also brings us to the question why so many commercial paddles have looms with round cross sections while traditional paddles almost without exception have looms with oval cross sections.  I suspect the reason is that is simply so much easier and cheaper to manufacture looms with round cross sections.
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Senin, 26 Desember 2016

Swedish Americas Cup Boat

I thought Id post some more pictures of the Swedish Americas cup boat.  Far as I know, its the same as all the other contenders boats except for the paint scheme.  These pictures have no particular significance other than that my shop is right next to Alamedas seaplane lagoon where the Swedish team is keeping their boats and so I see these boats on a pretty regular basis and occasionally feel compelled to take pictures of them when they are looking particularly impressive.

A shot of one of the smaller boats.  The Swedes have one with white lettering and one with red lettering.

On an afternoon when the wind is blowing, both of the Swedish boats are out on the bay with their support boats following behind.

A few Saturdays ago, the Swedes put their big boat in the water.  Crane at the right. 

A tighter shot of the big boat.  Crew members in red shirts hang around on shore, probably drinking something with alcohol in it.

Meanwhile, the smaller boats are still around.  The rainy season has started.  Hence the clouds.

The big boat being towed into the seaplane lagoon with the reserve fleet in the background.

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Sabtu, 24 Desember 2016

Seat blocking epoxys love affair with tape

It has been a busy week with band rehearsals & back-to-school shopping, but last night I did manage to get the blocking for the rear seat attached.

I had covered the ends of the seat with blue painters tape in an effort to keep from gluing the seat down just yet. In short, it worked. But, after I had pried the seat off of the blocking, I was reminded that epoxy really likes blue tape. Epoxy likes blue tape a lot.

Thats a mess to clean up another day.


16 clamps to install 2 pieces of seat blocking? Yep. Some to clamp the seat to two levels; some to clamp the seat to the center support; some to clamp the blocking to the seat; and two used as spreaders to push the blocking upward & outward.




The larger Irwin bar clamps are great, because you can switch them around & use them as spreader bars.

Port side blocking attached.

Starboard side blocking attached.

No, I wont win any prizes for fit and finish. (Im not trying to.) Even with the imperfect fit, the thickened epoxy is tenaciously holding the little mahogany block to the side of the boat.

I can fill in the remaining gaps with epoxy when I encapsulate the inner surfaces of the hull.



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slot gasket

September 13, 2014 -

I got tired of sanding, so moved on to putting a mylar gasket over the centerboard slot.  The slot is about 5 feet long and an 1.5" wide, therefore if left open will create a lot of noise and turbulence when moving through the water.

I purchased a 2" wide X 10 long piece of gasket material (mylar one side, dacron on the other) and bedded it with Sikaflex polyurethane sealant.  I hate using this stuff as it is messy as heck.  Cleanup needs to be a solvent such as paint thinner/mineral spirits/laquer thinner/brush cleaner and gloves are a must.  This is sandable after it sets up.

Slot gasket set in polyurethane sealant.  will sand when it all sets up.


this leaves me with one side of the hull left to sand prior to painting with System Three LPU primer.  Weather looks good this week.

9-16-14
Sanded the remainder of the hull and the protruding sealant.  As they say, "close enough for jazz".  I am painting this week.


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Kamis, 22 Desember 2016

Fiberglass and other crimes

Sometime ago I got the notion that when you build something yourself you get to control how much violence you do to your environment and to yourself.  Your time is your own and you know how to price it when youre doing something for yourself and so you can make good decisions rather than the strictly economic decisions of someone who has no goal other than to make money.
If you buy something thats been manufactured disreputably, the seller usually takes great care to keep you ignorant of how much damage was done to the environment and the people who manufactured the thing. The seller usually tries to create a happy shopping environment that floods your brain with endorphins so that you forget all about the awful conditions under which the thing was made, assuming that you ever cared how the thing was made or were able to find out how it was made if you did. Or as someone once said about sausages, you dont really want to know what went into them. And so if you buy anything you probably dont want to know how it was made.

So when somebody actually says something honest about a manufacturing process, I am heartened, and so I quote here from Thomas Firth Jones excellent book, Low Resistance Boats.
"Fiberglass work is alienating, because no matter what suits are worn and fans are run, its smelly and filthy and unhealthy.  Its possible to lay up a hull or two nonchalantly, but if the work is done steadily, alienation sets in. Ive never known a conscientious fiberglass worker, and when opportunity arises, many will go beyond carelessness to sabotage.  Urinating into the mold is standard.  Beer bottles and pails of uncatalyzed resin are routinely chucked into keels.  Whenever possible, the work is done drunk."
Well, you get the idea.  Jones goes on to advise the prospective buyer of a fiberglass boat to get it from a shop that doesnt do enough fiberglass work to be alienated by the process.

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Two Coats of Sea Foam Green

I let the first coat of Aquagard 190 primer cure overnight, then rolled on a second coat. After a little more than the 4-hour recommended drying time, I opened my can of Aqua Gloss Sea Foam Green.

I havent gotten so excited at the sight of a color since I was 4 years old & opening a big, brand-new box of Crayola® Crayons. The Sea Foam Green paint just seemed to glow inside that black-lined can!

I rolled on the first coat, and let it cure overnight. Then I rolled on the second coat this morning.

So far, so good.


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Rabu, 21 Desember 2016

winter update

No progress due to work and weather.  Good news is the winter tarp on the clam skiff survived Snowmagedon.  21" of snow in 18 hours, 45 mph wind with higher gusts. The ridge pole is the mast I built for a Birdwatcher II,  decided to abandon that idea after the mast weighed more than I care to lift as a static load.


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Minggu, 18 Desember 2016

centerboard shaping

The Centerboard has been roughed out to its approximate final shape and I have become a tad obsessive compulsive regarding the final shape.  The photo shows the NACA 0008 shape as it seemed to fit the final shape of the tip of the foil the best.  the NACA 0009 might be better.  My plan is to set a dado router bit to the depth indicated by the template and then  set a guide for the router to follow.  I will set the guides as expanded lines up the foil at several stations as the template can be expanded to fit the width at each point.  I used the plotter at http://airfoiltools.com/plotter/index  be sure to select "no margins" on the printer or things get compressed.  I can generate a NACA foil for several points along the board and then connect the points to expand the lines through the taper.  The router would then follow the lines to cut the lines to be planed to.


 Area that will be inside the trunk is clearly marked.  router will be used to go vertically up and strike marks to plane to.
 I have no idea how I will shape the tip, other than just rounding it off.


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Planking progress stalled by need to encapsulate stem

As January keeps winding on, it seems as though I’ve had a million things to juggle or deal with that keep interfering with my boatbuilding progress.

I am making progress, however.

I’ve gotten the forward starboard plank screwed into position. It is not epoxied on yet, however. The simple reason is the fact that I have not yet encapsulated the stem, which is still bare plywood all the way around. Once the planking is on, it will be very difficult to reach certain parts of the stem in order to coat it with epoxy, (or “encapsulate” it), as protection against moisture. So, I need to encapsulate the stem before I permanently attach the planking.



The forward plank on the starboard side is screwed into position.

Detail view at the stem
In this detail view, you can see the how the added chine strips got blended into the shape of the forward bend in the chine.

Unfortunately, I don’t have on-hand the proper type of epoxy for encapsulation. What I have on-hand is System Three Silvertip Gel Magic. VERY viscous stuff that is great to work with to glue parts together. However, I need something much thinner for encapsulation. I liked the Gel Magic enough that I decided I’d try another System Three product, so I ordered the regular Silvertip epoxy. It should be here early this week.

In the meantime, I have fitted, glued and screwed the butt block into position on the port side of the boat. 

Fitting the butt joint on the port side. Without the butt block in place, the forward plank does not match the curvature of the aft plank.

By comparison, here is the butt joint on the starboard side. The butt block allows the forward planking to match the curvature of the aft planking.

The port side butt block, before being epoxied into place.

The butt block epoxied into position against the aft planking on the port side.

The next step will be to encapsulate the stem & a few other parts with 2 or 3 layers of the Silvertip epoxy. Then, I can permanently attach the starboard planking. After that, the rest of the port side planking.
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Sabtu, 17 Desember 2016

Almost

One more cycle of fill and sand, and the fairing should be done.

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Kamis, 15 Desember 2016

The Camping Yurt

I built a ten foot diameter yurt suitable for camping.  The ten foot diameter seemed suitably large for comfort but not so large as to provide a transportation problem and also not so large as to overflow available camping spots. Our intent was to give it a good workout in Kings Canyon National Park.  By and large, it worked out with minor problems.  Pictures and comment below.

This shot was meant to show how small the yurt looks in a natural setting.  It looked much larger when I first set it up in the driveway of our house. We left the roof cover off so we could look at the stars at night.
Here is a picture of the yurt in the afternoon when the sun is hitting it.  We peeled back the wall for better air circulation.
Here is the yurt with the roof cover on.  We may still sew darts into the overhanging portion of the roof to take up the wrinkles.
After we got kicked out of Kings Canyon due to government shutdown, we found a camping spot in Sequoia National Forest right next to a Jeffrey pine.
Here is a longer shot of the yurt to show its size in proportion to the pines.
And then it snowed.  Clouds moved in in the morning and we put the roof cover on.  I had not yet made a smoke hole cover so a plastic tarp had to do the job.  The snow all melted once the sun came out.
A closeup on the tension band that holds the top of the wall in against the pressure of the roof poles.
And a closeup of the roof pole to wall junction.
The tarp leaked a little since laid flat over the smokehole ring to which I had not yet added any arch.  Here I have added some willow twigs to remedy that problem.
All in all, we were pretty happy with how the yurt behaved.  Next addition, some flooring to isolate the bedding from the ground and a small wood stove for heat.
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Next stop Transom

The side planking is all on now. So, the next step is to cover the transom with Meranti so that it will match the deck.

First, I made a posterboard template of the transom. Then I positioned the template over an attractive grain pattern on the Meranti plywood. I traced the template, then drew a secondary line extended 3/4” outward from the tracing. I cut to this secondary line so that my transom cover would be oversized sufficiently for me to fit and position it as needed.


Posterboard template & oversized transom cover.
The next step will be to attach it.

To help with this, I have ordered a Raptor stapler and some 9/16” Raptor staples. The Raptor staples are plastic. So, you can simply sand off the extraneous end of the staple once the stapled piece of wood is bonded to the sub-layer. This should leave little or no evidence of fasteners, as would be the case with screw heads, etc.

That’s the idea, anyway. The stapler should be here early this week. I’m looking forward to trying it out.


 Side planking trimmed at the bow.

Side planking trimmed at the bow.
 
Fairing progress on the side planking.

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