Tarp Ridgeline strength question

**Ruffage** · 11-09-2017, 11:35

Hello all

Been getting ready to make a new Winter type tarp. This will be my second one.

One of the problems my first one had was the ridgeline leaked. It was made basically by sewing two pieces lengthwise together so that the sewn seam was the ridgeline.

This method of joinery was simple in that you only need to sew that length of materiel in one spot but it puts a lot of little holes in a place that ends up right over your body when the hammock is strung under the tarp. While you can do a seam seal, I had a thought.

IE (Not to scale):
tarpdrawing1.png

I was wondering what would the stresses be in the centre line of the tarp if there wasn't a sewn ridgeline at the same place where the ties outs would be. Below is my questionable config.

tarpdrawing2.png

The idea being to take one of the lengths of material and further split in in half lengthwise. Then sew one of the half's to one side of the first piece and the other half to the other side first piece. This would leave you with a ridgeline without a sewed seam in it and thus no holes but would not have the folded sewn seam as a strength point in the ridgeline.

Has anyone tried this and if so what was the conclusion?
Thanks for reading this far.

Mike

**HarryRSole** · 11-09-2017, 12:03

I just finished two new tarps and for both I used the French felled seam for the ridge line. That's a real strong seam and I haven't seam sealed it at all and it seems fine in the rain. One thing that I did was I made a continuous ridge line tarp suspension and I kept it outside of the tarp. I didn't want the zing-it rubbing on the bottom of the tarp. The center tie outs are long triangles that distribute the stress over a long area. I can send you some pictures if you need them for reference.

**Ruffage** · 11-09-2017, 12:07

That's pretty much the way I constructed my first tarp and used the continuous ridgeline as well.
Was just curious if this other idea would make much of a difference.

One thing about the second idea is that it should be easier to add ties outs to the tarp for mid line as you are already sewing in that area.

**mathineer** · 11-09-2017, 14:17

Consider a standing French seam covered with grosgrain. It's stronger, and Jellyfish says it doesn't leak! :-)

I think it was KitsapCowboy that described a tarp he made using this approach that gave me the idea. Now I'm planning a winter tarp in the near future, and I believe I will use that approach.

mathineer

**scrope** · 11-09-2017, 15:38

One of my tarps is the Kammok Glider:

https://kammok.com/products/glider

It's made without a center seam and I've never seen any detectable stress failure on the tieouts for the ridge line connection. You now have two seams to worry about but even if they were to leak, I doubt they would cause a problem with wetness.

Sort of nice looking up and seeing nothing but an unblemished surface.

**Ruffage** · 11-09-2017, 18:17

Originally Posted by scrope

One of my tarps is the Kammok Glider:

https://kammok.com/products/glider

It's made without a center seam and I've never seen any detectable stress failure on the tieouts for the ridge line connection. You now have two seams to worry about but even if they were to leak, I doubt they would cause a problem with wetness.

Sort of nice looking up and seeing nothing but an unblemished surface.

That's exactly the idea I had as well. Even if the the seams decide to leak, they are not directly above you.

thanks for the evaluation of the stresses.