tarp centre seam direction- does it matter?
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Joseph Williams
(deadogdancing) - F

Locale: SW England
tarp centre seam direction- does it matter? on 11/29/2007 02:36:23 MST Print View

With a large tarp, like an 8x10, for instance, does it matter whether you pitch it with the seam running along the ridgeline, or across it?

I have a golite 8x10 with a seam that runs crosswise to the longest edge of the tarp, meaning that when I pitch a long a-frame, it runs across the ridgeline rather than along it.I prefer the a-frame longer rather than wider, as length seems to matter more for staying dry!

If the knowledgeable tarp-builders on this board reckon that's ok, I'll dive into doing some other improvements to make it worthy of a longer hike, like re-hemming the edges to get rid of the grommets and replace them with loops, and adding lifter loops. Any thoughts would be much appreciated!

Joe

Edited by deadogdancing on 11/29/2007 02:38:33 MST.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: tarp centre seam direction- does it matter? on 11/29/2007 03:55:33 MST Print View

Hi Joseph

> does it matter whether you pitch it with the seam running along the ridgeline, or across it?

Seam along the ridge line, definitely (imho). Adds strength.

Cheers

Joseph Williams
(deadogdancing) - F

Locale: SW England
prototype on 11/29/2007 04:28:40 MST Print View

fair enough...it certainly seemed that way when I thought about it...perhaps the golite will just have to be a tester, and I'll build another one from scratch if I want a big tarp for long trips. Thanks for the feedback!

J.

Jan Rezac
(zkoumal) - MLife

Locale: Prague, CZ
Tarp ridge on 11/29/2007 15:42:43 MST Print View

If you are going to use just tieouts to pitch the tarp, then the ridge seam is necessary for strength it adds to the fabrics. Moreover, consider catenary cut to avoid wrinkles.
I use flat rectangular tarp of similar dimensions (3 x 3.5 m). When I pitch it in A-frame ay, I allways use strong string (2mm kevlar) for the ridge to add some strength. It withstood several storms above treeline without problems and I'm sure that without the ridge line, the wind will rip off the tieouts easily. In that case, it doesn't matter where the seam is.

Frank Deland
(rambler) - M

Locale: On the AT in VA
center ridge on 11/29/2007 20:02:04 MST Print View

When pitched over a hammock, not using the center ridge, but having the seam along the diagonal, you only need two tie-outs. See Jacks R Better 8 x 8 tarp.

Edited by rambler on 11/29/2007 20:06:14 MST.

Joseph Williams
(deadogdancing) - F

Locale: SW England
rope under ridgeline... on 11/30/2007 02:18:25 MST Print View

thanks for the tip Jan, I think I'll start doing this...

Michael Davis
(mad777) - F

Locale: South Florida
Re: center ridge on 11/30/2007 11:29:25 MST Print View

Love my Jacks R Better 8 x 8 tarp!

And, they are on sale right now at jacksrbetter.com

John S.
(jshann) - F
Re: Re: center ridge on 11/30/2007 12:33:03 MST Print View

Why does JacksrBetter call their tarp 8' x 8' when it's 10 inches shorter than that on both sides, 7'2" x 7'2"? Call it what it is!

Jan Rezac
(zkoumal) - MLife

Locale: Prague, CZ
Additional tip for ridge line on 11/30/2007 12:42:19 MST Print View

I should add a trick that makes pitching the tarp with ridge line much easier, especially when you are working alone:
firstly, I set up just the line, what is easy between two trees and not difficult using two A-frames made from sticks or poles. Then, I align my tarp on the line and attach the central tieouts to the line with short loops of string by peussik knots. Using prussiks, I can adjust it's position and make it perfectly taunt. And because the tarp is well fixed now, I can easily stake all the guylines at it's perimeter.
On longer trips, I'm to lazy to tie all the knots every evening, so I store the tarp attached to the ridgeline and with all the guylines.
There's of course added weight of the long and rather strong string, but it has multiple other uses during the day...

Frank Deland
(rambler) - M

Locale: On the AT in VA
easy pitch on 11/30/2007 16:33:43 MST Print View

I stow my tarp in a snakeskin, tie the ends to trees like I would if using it over a hammock. If it is not raining I just leave it in the skin, and sleep under it. If rain awakens me, I can open up the tarp, reach out and set the stakes without ever leaving my bag. Haven't gotten soaked yet! Hmm, I'll have to measure it. I remember the diagonal seam was just under 11 feet. It's a homemade job, but Jack helped me with it.

Joseph Williams
(deadogdancing) - F

Locale: SW England
prussiks and snakeskins.... on 12/01/2007 14:22:29 MST Print View

Jan, thanks for that, I was just going to ask what knots you were using!

Frank, is a snakeskin a way of rolling the tarp up? I'm unfamiliar with the expression- seems good to set it up so that you can star gaze, but quickly unfurl the shelter if it rains...