I’ve searched the web in vain for a pattern for a 1-person tarp with a catenary cut on the main ridge line. I don’t care whether it has ‘beaks’ in front or back, or not - mainly want to keep it fairly simple - it will be my first attempt at a tarp.

I will even settle for a web page or book page that tells me how to lay out a catenary cut ridge line seam. I guess my main question is how many inches of deflection off the straight line should I build in per linear foot of seam? And I suppose this changes per the material I choose to use and so on..

There was a thread on this forum a few years ago where a guy posted a link to Six Moons Designs, where they were offering a pattern for a tarp with cat cut ridge line. When I clicked on it I got an error. I went to the Six Moons web page and searched for “pattern” and came up empty.

Here’s what I’m looking to come close to: an Oware Cattarp:

http://www.owareusa.com/images/solocat.jpg

Any help out there?

I believe that the file you want is named Pattern_NightWing.pdf.

If you Google that name, there is a Six Moon Designs entry on the first page with a [pdf] in front of it. I donwloaded it and it has the same file that I have in my archives.

OLTS

For sizing your tarp check out solo tarp specs from manufacturers like Mountain Laurel Designs and Oware.  I don’t know of any plans available for download except for the Six Moon Designs Night Wing (http://sixmoondesigns.com/community/myo_NightWing.html).  Quest Outfitters sells plans for a two person cat ridge tarp.

I’ve made five tarps and tents with catenary ridgelines.  I use about 1/3” drop per foot of ridge length.  For instance, a 9’ ridgeline would have 3” deflection at mid span.  I use 1/4” per foot for edges. For instance a 4’ edge would have 1” deflection at its midpoint.

This forum thread at Backpackinglight.com could be helpful:  http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=24439&disable_pagination=1
It includes a link to my catenary curve spreadsheet.

Hope this helps,

Lance

Lannce and OLTS -
Thanks so much for the replies and all the info - you guys have been a great help! I’m inspired to push on now.

You might find this interesting…
I designed the TautTarpTent a number of years ago using a surface optimization program called The Surface Evolver.  It turned out great (IMHO)  I had pictures and the design posted on thru-hiker originally but it got wiped out when the forum software changed.
I have full size dwg files for both the tarp panels and screen panels that include seam allowance and reinforcements.  Unfortunately, I cannot attache them to this post (nor a zip file) so if you want them send me a PM.
If anyone builds one, I’d love to hear about it!
Enjoy,
joe

solowandslow - 28 April 2010 01:58 AM

I’ve searched the web in vain for a pattern for a 1-person tarp with a catenary cut on the main ridge line. I don’t care whether it has ‘beaks’ in front or back, or not - mainly want to keep it fairly simple - it will be my first attempt at a tarp.

I will even settle for a web page or book page that tells me how to lay out a catenary cut ridge line seam. I guess my main question is how many inches of deflection off the straight line should I build in per linear foot of seam? And I suppose this changes per the material I choose to use and so on..

There was a thread on this forum a few years ago where a guy posted a link to Six Moons Designs, where they were offering a pattern for a tarp with cat cut ridge line. When I clicked on it I got an error. I went to the Six Moons web page and searched for “pattern” and came up empty.

Here’s what I’m looking to come close to: an Oware Cattarp:

http://www.owareusa.com/images/solocat.jpg

Any help out there?