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Turtle Cover

March 9, 2010
Turtle Cover

-Concept-

Design Intent: Create a waterproof cover for the entire boat which could be comfortably worked under, lived under and easily dis/assembled.

Design Dates: Summer/Fall 2007

Prototyping Dates: Fall/Winter 2007-2008

Build Dates: Winter 2008 – present

Major Design Contributor: Matt W. – Killer Architect

In the summer of 2007, Matt and I were working together for Case Design in Matt’s 2nd floor, over-the-coffee-shop-office in Ballard. I had been working on the CAD framework for this “cover” project for a few weeks in my free-time when, after 5pm on a sunny Friday, I happened to verbally drop my token ideas into Matt’s vending machine-mind of good design. Within minutes his spiraling synapses had unscrewed and released a wholesome package, letting it fall freely into the collaborative chamber.

My original idea was to bend some poles, attach them to the boat stanchions, and precision cut some canvas- make a barn. Matt’s suggestion was to sculpt and suspend a floating canvas shelter with an overhang- craft a shell. His input was fundamental to this project and his ongoing collaboration through the first winter was critical in keeping the design clean and functional. Thanks dood!

Fond of turtles, and thus shells, wearing my turtle t-shirt that day in fact, the design quickly took shape and I never looked back.

-Schematic Design-

We used the 3D model I had created from digital photos using photogrammetry to start the collaboration. The modeling bounced back and forth between AutoCAD, and Sketchup utilizing the best of each.

The rough-hewn shape of the shell as seen from Sketchup.

AutoCAD 3D was necessary to move the model from the photogrammetry output to Sketchup as well as to make accurate working planes and measurements. In this front view wireframe, the unintended turtle-like characteristics are evident.

The morning after the shell design was hatched, I found this guy on the sidewalk along Lake Washington boulevard. Synchronicity, as opposed to “X”, often marks the spot. Nature has much everything to offer for designers.

-Design Development/Prototyping-

A very special custom “bracket” was necessary to support the shell from the existing lifeline stanchions.

I spent weeks designing and fabricating this bracket system from common hardware store and boat store stock.

The finished bracket:

In the end, I employed aluminum flat-bar, sweated-copper fittings, various 516 stainless-steel parts, a length of cord, and the round-seizing which I enjoyed learning from the Marlinspike Sailor book that came with the boat. As I had to make 16 of these assemblies, I got a lot of practice tying the round-seizing.

-Design Development/Tool Making-

The use of Easton 7075 anodized aluminum poles was critical. They are light, super strong, and it is possible to pre-bend them to allow for small radius arcs. After an expensive and inaccurate flirtation with factory pre-bent poles, I purchased straight poles from the local and knowledgeable folks at Tent Poles for You, and built a machine to pre-bend them myself.

Turtle Cover Overview

My specification drawing to Easton for the pre-bent poles. My mistake was that many of the poles ultimately did not need a pre-bend.

Hence, the need for a machine which would both custom pre-bend as well as un-bend some of the bent poles I had ordered.

Using pulley-wheels from the climbing section at REI, aluminum flat bar, and some stainless steel hardware- the middle wheel cinches in and permanently bends the 1/2″ tube as it is shoved through. To buy a similar machine would have cost me $1000. This one cost about $50 in materials and took me a few days to design and build.

Works like a charm. There’s something primordially satisfying about creating a machine that works.

My mechanical drafting professor would cringe if he saw this drawing, but, as I was also the machinist, all was fair game.

-Construction Prep-

This project was my introduction to the art and science of fabrics and sewing. My industrious friend Ken and my Mom showed me some basics and the rest was a trial by fire. I did a fair amount of practice and some fabric mock-ups of specific sewing details before starting in on the actual cover.

I annihilated my first $20 Goodwill Store sewing machine within the first few bobbin-loads – first stripping and replacing the plastic gears in the low-end Singer then toasting the motor while trying to stitch through too thick a stack of hardy marine fabrics.

Amazing machines, even the cheap ones- a sign of an industry as old as industry itself

My second $20 Goodwill machine is a champ. It’s a Nelco- Japanese made, no gears, all cam-shafts, simple, indestructible

Below is a small mash of video showing the boat as metal shop, machine shop, and sewing shop. This is all video from early 2008. It shows the Bruja Dulce harboring creative and industrial ferment- the 15 amp AC shore-power cord from the Leschi Marina supplying loud music, ample saw-power, and ample lighting. Nowadays, generating and storing my own power, the boat is quieter, cleaner, and more prudently lit.

-Construction-

I began sewing the panels of the turtle cover in July, 2008. I really didn’t know what I was doing. I had considered making development drawings from precise measurements to cut the panels of fabric. I learned quickly however that craftsmanship in fabrics must be defined first by a keen tactile technique and not by an incredible 3D model and accompanying set of 2D drawings- there are just too many variables involved.

In a nutshell, I started at the front:

Then pulled, clipped, and marked each panel of fabric on each pole and sewed it up.

It may sound easy but it’s not. No. It’s not easy. There were a ton of details- all which needed creative refinement.

Here’s one:

Using standard “common sense fasteners”, this detail allows each fabric panel to attach alone or in tandem around a support pole- a critical feature for a long list of reasons.

-Result-

I love my shell. Waking up in the V-berth, looking up through the hatch, seeing a brightly lit, airy, waterproof skin between the boat and the Pacific Northwest winter makes me feel a little more secure. There’s still a couple of smaller panels left to sew, but three quarters of the Bruja Dulce’s leaky teak deck and exterior woodwork have been mostly dry all winter, nothing has broken or ripped this whole nasty season, I can assemble or disassemble the cover by myself in 30 minutes, the wind, one of my main concerns for this structure, has yet to cause a problem and thus the entire concept, as far as I’m concerned, is sound. I am considering how I might make a kit out of this project- something other sailing seamsters and seamstresses could use recreate this project for their vessels.

I got the most pleasant surprise the first time I saw the shell endure 20-25 knot gusts. Instead of collapsing and tearing itself apart, it gracefully inflated. I will be curious to see the wind speed which first begins to cause it harm. Here’s a couple clips:

When I first started college at San Jose State- a few handfuls of years ago- I was an Aerospace Engineering major. This lasted for one whole semester. The only reason I could give for this intuitive choice was that I wanted to work in wind tunnels. I know this “wind-tunnel” is not exactly what I was thinking of, and the work I have to do on deck in the tunnel is far from anything I could have imagined doing back then, but I like the idea that just maybe some aspect of that former self is finally being expressed. The universe works in mysterious ways.

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6 comments

  1. WOW!!! It looks great! I actually got to witness the pole bender first hand, remember??? You definitely need to get a patent on this. You could retire by the time you’re 35!!! ūüôā

    Congrats!!

    Love you,
    Aunt Carol


    • Thanks Auntie
      I remember for sure. You’re one of the few (two?) people who have seen the bender bend- we’re a small and kooky Order. Our relic is now it’s tucked away deep in the bowels of the Sweet Witch. hm?

      Shoot, I thought I was already retired. Oh, kid!
      We have a client at Case who is a patent attorney. I’m working up the nerve to ask advice. Never hurts to ask!
      Luv ya!


  2. I continue to be amazed even though I knew most of this was going on, I had no idea how involved it really was. I love seeing all the drawings and schematics – reminds me of Papa’s drawings of things he was working on. I agree with Carol….it would be great to be able to patent the cover! I’d think your pole bender might be marketable too?? I’m really loving he depth of your blog….getting to hear about all the details is really great! And for you to have this record of it all is invaluable! Take good care….love you! Mom


  3. What a man!!!!! Love all this!!!! These pictures are remarkable and your talent exceeds all expectations. This whole “Turtle” concept is wonderful and I agree “all this” should be patented. I agree with Fran, your drawings and things remind me so much of Papa and things he use to do. I continue to be so very proud of you and all you are doing. Love you so much.


    • Thanks Gramma,
      Your support means a lot. Knowing inventiveness is in our genes means a lot too. He’s watching- and whispering:)
      Love you.


  4. That’s awesome!



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