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  1. #11
    Brian's Avatar
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    Quote Originally Posted by FarStar View Post
    You lose this versatility with a tarp having a catenary ridge line.
    Farstar, there is a difference between a Cat cut ridgeline and a cat cut perimeter. A catenary cut ridgeline does limit the pitching options of the tarp, but I have never felt the need to add this limitation to any of my tarps, and I don't recommend it for any DIY'ers either. Putting curves on the perimeter edges of the tarp still keeps the tarp taught, while only slightly limiting your pitching choices.

    A flying diamond for example, isn't really practical with a cat cut ridgeline, but with cat cut edges it works like a charm - it's just a matter of tensioning the tarp right. It may take and extra minute or pass around the tarp pulling your guy outs tight one more time, but once it's set up, it stays tight and quiet through the night. Mikeinfhaz is dead on with the 'sil forms it's own false cat ridgeline' - the stretchyness of the fabric really lets it conform to how the wind is blowing it and how the guyouts pull it.


    6FO: Try adding the three inches to the length of the tarp, then cut the curves. You keep the benefits, and don't lose much (if any) coverage. Although just doing the long, parallel to the ground sides of the tarp should still give you most of the benefits of the catenary cut. The 'short side' curves really come into play with angled cuts like in a hex or other shaped tarp or with non A-frame pitches. But they still help with the overall guying out of the tarp, especially the area near the corners.

    Brian
    OES

  2. #12
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    How effective catenary edges, catenary ridgelines, and catenary darts are with silnylon tarps is a function of the overall size, the shape, and the desired pitch(es) of the tarp. You have different physical things going on that is largely dependent on where the stakes are and how they are tensioned relative to each other and the particular stretch characteristics of silnylon.

    Silnylon has wicked stretch characteristics. It is a woven fabric and one of its characteristics is that it stretches much more along the bias of the weave. Pulling on the tarp to take out that stretch or designing it out is important if you want to get it initially taut. If you want to keep it reasonably taut overnight, especially when it gets wet, you need to use some shock cord with the side guy lines to help take up the overnight/wet stretch you usually get.

    On a tarp with everything cut straight you can get about the same results as one with latest, greatest and most imaginative catenary shaping if you use enough tieouts, guyline, and stakes... and this can include panel pullouts as well as edge pullouts. Well designed tarps with catenary shaping can be looked at as reducing tieouts, stakes, setup time, etc., but they aren't as easy to design or make.
    Youngblood AT2000

  3. #13
    Senior Member 6 feet over's Avatar
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    Quote Originally Posted by Brian View Post
    6FO: Try adding the three inches to the length of the tarp, then cut the curves. You keep the benefits, and don't lose much (if any) coverage. Although just doing the long, parallel to the ground sides of the tarp should still give you most of the benefits of the catenary cut. The 'short side' curves really come into play with angled cuts like in a hex or other shaped tarp or with non A-frame pitches. But they still help with the overall guying out of the tarp, especially the area near the corners.

    Brian
    OES
    Iím really only interested in pitching a tarp over a hammock to keep it dry. I guess this would be considered an A-Frame pitch.

    The other issue Iím looking at is I seem to have ĎNeo-diseaseí, and am really only interested in having a camo tarp. I have some reasonably light weight nylon material from Wal-Mart, but I guess this isnít really sil. I guess I have to pay the weight penalty until someone comes out with camo sil.

    Lacking real camping/hammocking experience, Iím willing to carry a larger, heavier tarp to assure my hammock and gear stays dry.


    Quote Originally Posted by Youngblood View Post
    How effective catenary edges, catenary ridgelines, and catenary darts are with silnylon tarps is a function of the overall size, the shape, and the desired pitch(es) of the tarp. You have different physical things going on that is largely dependent on where the stakes are and how they are tensioned relative to each other and the particular stretch characteristics of silnylon.

    Silnylon has wicked stretch characteristics. It is a woven fabric and one of its characteristics is that it stretches much more along the bias of the weave. Pulling on the tarp to take out that stretch or designing it out is important if you want to get it initially taut. If you want to keep it reasonably taut overnight, especially when it gets wet, you need to use some shock cord with the side guy lines to help take up the overnight/wet stretch you usually get.

    On a tarp with everything cut straight you can get about the same results as one with latest, greatest and most imaginative catenary shaping if you use enough tieouts, guyline, and stakes... and this can include panel pullouts as well as edge pullouts. Well designed tarps with catenary shaping can be looked at as reducing tieouts, stakes, setup time, etc., but they aren't as easy to design or make.
    Iíve asked this before: does anyone use intergrated shock cord on their ridgeline rope? Since these materials stretch, wouldnít a short amount of in-line shock cord (if only on one side) take up some of the ridgeline slack from overnight stretch?

    6
    The harder I work, the luckier I get.

  4. #14
    Senior Member angrysparrow's Avatar
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    Quote Originally Posted by 6 feet over View Post
    I’ve asked this before: does anyone use intergrated shock cord on their ridgeline rope? Since these materials stretch, wouldn’t a short amount of in-line shock cord (if only on one side) take up some of the ridgeline slack from overnight stretch?
    I haven't seen anyone using shock cord on their ridgeline, only on the guy outs.

    From my tarp usage, when pitching I find that I can pretty much pull enough tension on the ridgeline to 'pre-stretch' it. That either negates the need to re-tighten the ridgeline or to only have to adjust it once minimally. Taking up the slack in the width of the tarp seems to be more beneficial to maintaining the taut pitch. YMMV
    ďI think that when the lies are all told and forgot the truth will be there yet. It dont move about from place to place and it dont change from time to time. You cant corrupt it any more than you can salt salt.Ē - Cormac McCarthy

  5. #15
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    Quote Originally Posted by 6 feet over View Post
    Iíve asked this before: does anyone use intergrated shock cord on their ridgeline rope? Since these materials stretch, wouldnít a short amount of in-line shock cord (if only on one side) take up some of the ridgeline slack from overnight stretch?
    I don't use shockcord(s) on the ridgeline ropes. There is a lot more tension on the ridgeline as the two ridgeline ropes pull against each other and the side tie outs pull down on the ridgeline as well. That makes it more difficult to do much good with shockcord on the ridgeline ropes.

    If you wanted to hang your tarp from a solid ridgeline that went from one tree to the other, that might change those dynamics and keep the ridgeline from dropping when the silnylon stretched. I haven't notice the ridgeline dropping as being a problem but I haven't paid much attention to it.

    If you mess with different techniques of using shock cord, don't get carried away with it such that the tarp can move enough to not cover you well. I tried that when I was using a Hennessy Hammock until I noticed the sky overhead in a strong wind one time. I was lucky and the wind stopped before the rain came down.

  6. #16
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    Brian,

    Thanks for the information. You've got me wondering -- not enough to unpack my tarps and check -- whether my two catenary tarps even have a stitched ridgeline. I'm guessing the ridgeline can't be catenary unless there's a seam there. (Ignoring the fact that even a straight cut ridgeline will hang a bit and naturally form a catenary curve in doing so.) The two tarps in question are a Speer Winter Tarp and an Outdoor Research Helium Awning. Perhaps Youngblood can say whether his SWT has a seam along the ridgeline and, if so, if it has a catenary cut.

    FarStar

  7. #17
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    6FO,

    While I can appreciate a penchant for camouflage, if one is going to spend any time under a tarp during daylight hours, it's hard to beat the color gray. It admits enough light to eliminate the feeling of being in a cave, and the color of the light doesn't make one ill. And, the color blends fairly well in most environments.

    FarStar

  8. #18
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    Quote Originally Posted by FarStar View Post
    Perhaps Youngblood can say whether his SWT has a seam along the ridgeline and, if so, if it has a catenary cut.
    FarStar
    The SWT has a panel seam along the ridgeline but it doesn't have a catenary cut along that seam. Instead, it uses 4 strategically placed catenary darts. Since the corners of that tarp do double duty as flaps or doors, the catenary darts do a better job than a catenary ridgeline would do since they tighten the tarp and also act as virtual hinges for those corners. There are also 10 catenary cuts along the edges of that tarp that help with tautness.
    Youngblood AT2000

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