Make Your Own Gear: 5 Yards to SUL, Part 3 – Tarp
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I'm extremely happy with my tarp . . .
There are a few things that I learned, or experienced which may help someone else.I don't have a tally for the time spent on it, since it was constructed over the winter/spring and various weekends, but the time was MUCH MORE than listed in the article.
My biggest deviation from the original design was length. I added 10", based on comments by other users and a couple of scale mock ups that I constructed with paper. Some graph paper & tape makes this an easy task.
I did not change any other dimension. The finished tarp and bag weight was 7.0 oz. I have not weighed it with the guylines & tensioners yet.
I used the catenary curve .xls mentioned in this thread. I'm sure that I documented my settings, but I can't find them right now to report what I used. I think I was in the 400/500 range and I believe I used 110 for the ridgeline.
My first test of the tarp was on Santa Rosa Island. The island is known to be windy and I wanted to test how it would function in high winds. Since I had finished it days before the trip and hadn't set it up yet, I struggled in the wind. The biggest problem was getting it set up both low enough to the ground for the wind and high enough to get in.
I used Triptease coupled with a 1/8" reflective shock cord looped to create tensioners on the 6 non-pole guyline locations.
A NOTE ABOUT SET UP: I've now learned using the following method is easiest: 1. Stake the low end corners. 2. Set & stake the high end poles & then corners. 3. Return to the low end to stake the pole. 4. Adjust all the corners. 5. Stake the sides. 6. Adjust as needed.
I tried and tried to adjust the height of the "high end" so that it was high enough off the ground for me to get in. The problem was that the height of my goat poles was not enough to raise the end when placed as far away from the tarp as needed to outstretch the beak.
A friend in the group insisted that the poles should be on the inside. I disagreed, but relented mostly because I'd just read a thread about someone wanting to set it up like this.
In the end, the "high side" was too low to enter through but the "low side" had enough space to snake under, past the pole. Again, the wind played a factor in how low the tarp sat. Here's a picture of the tarp next to a Granite Gear tarp and a Sierra Designs tent during one of the wind storms:
I had expected the tarp to be loud in the winds, but with a taught pitch, it was MUCH quieter than either of the other two shelters. I was able to fit 2 people under the shelter and some gear.
PROBLEMS & RESOLUTIONS:
1. PROBLEM: During the windiest night (3rd night), the low end pole tore the re-inforcement patch.
RESOLUTION: During seam sealing, I used the mineral spirits solution to coat the tarp and the torn patch, I then cut and sewed another patch out of spinnaker and just sewed it over the other. I don't plan on putting a pole inside the low end again. I am using a clove hitch on the end of my pole tip and the pole outside the tarp.
2. PROBLEM: Not able to raise the high end high enough to enter the tarp without slithering on my belly. Also, the high end wasn't very high.
RESOLUTION: I created a patch out of a low weight denier PU fabric that I had purchased to re-inforce the storm seal of the mountain poncho. The patch has been sewn to the interior of the tarp and allows me to pitch the tarp using my trekking pole on the inside, allowing for a much higher pitch.Sam, I usually don't like to re-animate dead threads, but this is a great article and I felt I needed to share my efforts here and let Jay & others know. I think its one of the most influential articles on BPL, and surely has animated many to try out MYOG. Anyhow. Here two photos of the tarp pitched on the snow, some more here.
*sharalds: edited photo width *
I was thinkin to do something like this, so i can use it also like flat tarp.
Here is setup I've used to keep a shaped beak mostly taut at a variety of guyline angles. It might work with a "flat" beak if you thread the line thru five guyout loops instead of three.
If you'd like to try the circle method described above and have the space necessary, here's a table of radii for various lengths and 'bow'.
-Lance
Many thanks to Jay for an excellent article and to the rest of you for giving me the push to sew up this tarp. Also, a special shout out to Newton who gave me some advice in the planning stage. This afternoon–after several long days of sewing–I finished my first MYOG project.
I have yet to seam seal it, but the weight of the tarp itself without guylines or sealing is 11.05 oz (313 g). I used silnylon, and I added a foot to the length of the main body. I also think that the foot end panels are probably a little taller. If I remember correctly, I mismeasured over a few inches but when I realized my mistake, just decided to leave them instead of fixing it. I think I added three inches.
I learned a lot doing it too. The biggest thing I would do differently (besides actually knowing how to sew before I started) is add reinforcement patches to the different panels before sewing them together, or at least after doing the three main pieces (the main body and two beaks). It would have been a lot easier to work with smaller panels that laid flat (more or less, for the cat cut on the main body). Other than that, this article was fantastic. I'm looking forward to a lot of time underneath it.
Oh–and obligatory pictures:
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