Hex Tarp - Catenary Cut Ridgeline

**UltraHiker** · 11-04-2016, 06:53

Looking at some hex tarps online, I found some seem to have a catenary cut ridgeline, such as the Edge tarp from Warbonnet. Is it true that it has a cat cut ridgeline or it's just a look that comes from how it was hung and tightened?

Is a cat cut ridgeline necessary for the tautness of a hex tarp?

**fuzzyiguana** · 11-04-2016, 07:03

Originally Posted by UltraHiker

Looking at some hex tarps online, I found some seem to have a catenary cut ridgeline, such as the Edge tarp from Warbonnet. Is it true that it has a cat cut ridgeline or it's just a look that comes from how it was hung and tightened?

Is a cat cut ridgeline necessary for the tautness of a hex tarp?

Cat cut helps to eliminate tarp flapping and aids in the taughtness. I'm not familiar with Warbonnet tarps. Another great option would be Underground Quilts Catcut Hex Hanger Tarps. www.undergroundquilts.com/hangers/default.html

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**OneClick** · 11-04-2016, 07:16

Good question. I figured it was just the material stretching under tension vs. the stiffer grosgrain material along the ridgeline. But that's just a guess.

I think this is what you're talking about (ends slightly raised). Definitely visible every time I hang it and I don't even pull it very tight at all.

**GadgetUK437** · 11-04-2016, 07:16

Just because a ridgeline looks curved in a picture, it doesn't necessarily mean it has a cat cut. You can get that curve by wailing down on you guylines.

**UltraHiker** · 11-04-2016, 07:22

Thank you all for your quick replies and suggestions! Now I can see it is just the ridgeline under tension from the tie-outs.

**Billy Goat** · 11-04-2016, 07:26

I made all my tarps and I can say with certainty that the ridgeline is as straight as I could manage, but when I hang them they all have that "cat cut look"

Cheers,
the Goat

**GadgetUK437** · 11-04-2016, 08:03

I had been toying with the idea of a cat-cut ridgeline, but not necessarily for tautness.
I was thinking that I could pitch the tarp lower to the hammock with a curved ridgeline, without the ends of it pressing down on the hammock suspension (that is the limiting factor with a low pitch). But then I realised, if I did that, the ridgeline would be lower, but the edges of the tarp wouldn't... I'd have just made my tarp narrower in the middle!
I guess I could form the cat-cut, not by removing material in the middle, but by adding some at the ends, say by adding two darts of fabric into the ridgeline at the ends. Just sounds like more fiddle'n'faff to me.

**zukiguy** · 11-04-2016, 08:07

I just picked up a Kelty Noah's 12 and it's definitely got a very "cat-cut" ridgeline. If you try and fold it in half along the ridgeline and then pull the ridgeline taut you'll see the fabric pucker. The fabric is actually cut in a gentle curve before being stitched together at the ridgeline. For this and other tarps with a curved ridgeline they work better to either be suspended below a structural ridgline (or is it "continuous") or being held by individual cords at each end.

By contrast, tarps with a straight ridgeline generally work better when suspended over a ridgeline (zing-it, etc.). I've got both and I haven't seen a big difference between one and the other.

However, having a cat-cut along the edges of the tarp makes a pretty huge difference, especially with stretchy materials such as silnylon. Tension forces the cat-cut to material to pull from the center a little more, reducing the flap. Well....that's the idea at least.