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  1. #11
    joe_guilbeau's Avatar
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    At the beach you will see tarps pitched in a "Gull Configuration"

    Here is a video demonstration of the principals of what (@nanok) wrote.


  2. #12
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    Quote Originally Posted by joe_guilbeau View Post
    At the beach you will see tarps pitched in a "Gull Configuration"

    Here is a video demonstration of the principals of what (@nanok) wrote.
    (...)
    this is indeed pretty cool, thanks for sharing it. it is effectively a sort of wind supported hypar configuration, made with a square tarp, and it indeed demonstrates many of the aerodynamic principles affecting tarps in "steady winds".

    although it might not be something we would commonly configure when hammock camping, it really helps to see how it can work (not likely for camping, i mean, because this configuration relies on the fact it is very hot, and the wind is very welcome to help with that, the tarp is only meant for shade, so having the wind flow into and under the tarp is very welcome, as opposed to using the tarp as a wind breaker; if it would be raining or cold, the configuration would have to be adjusted, but it might be easy to do so without modifying it that much, in fact -- perhaps as easy as lowering the windward side, even; definitely a nice starting point to experiment from)

    i'm a fan of hypars and other tensile membrane structures, i think that's what tarps should be (that's why i talk about cat cuts, and tricks to simulate them when they are not there)

  3. #13

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    thx for all the thoughtful advice, everyone. ftr, i am talking about using cat cut silpoly tarps, usually warbonnets. Frankly my cheap rectangular ripstop nylon tarps are pretty bulletproof.

    i do understand a little about more optimal directional setups, mostly utilizing my sea scout level understanding (meaning it's rudimentary, and memory from decades ago) of how sails work and trim to remove luffing, etc. but when these heavy wind conditions arise, I'm inevitably in a place where trees are at a minimum and you have to take the two that are at all useable to hang from. sometimes that means i do have to set up with a wall to the wind. and i also use a centerpole, and sometimes also use the side pullouts with the pole mods, but in these conditions it can only do so much. again, particularly with the bridge poles being where i need the most help, not the center.

    the gull thing was interesting that there was no support at all in the back, but in addition to-- i think it was cmoulder's comments about temp, rain etc -- the conditions I'm talking about are rarely steady wind like on the beach; they are usually little to light breeze with sudden violent and prolonged gusts. (think the desert). if i can, i actually try to have the wind exit point (leeward side or ideally corner) set up in low porch or half porch; the intention there is to avoid having the leeward side billow from the inside creating a lot of tension on that corner,but instead allows the wind more of an escape route, if you will. but actually thats what ripped my mountainfly last month.

    judging from your comments, i guess my downfall in that case was using dyneema and then using an adjacent branch as an anchor; the wind whipped it and the tarp failed, not the shockcord loop; and if i had staked it instead of using a branch, the stake probably would have come loose instead of the tarp failing.

    i am super curious about what's wrong with a horizontal CRL. please tell me more!

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  4. #14
    cougarmeat's Avatar
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    Turtlefeet, there are two (or more) schools of thought on ridgeline setup. One school likes a split ridgeline - each side of the tarp has its own line that goes around the tree. This uses minimum line but 1) it makes the tarp itself part of the “load bearing” component and you need to have enough line on each end for the largest trees you’ll encounter - or at least one long-ish end if you’ll never need to tarp between two large trees. The other school (my current school of thought/preference) likes a continuous ridgeline (CRL). A single line is connected between the two trees and the tarp is hung off of it - with Nama claws, prusiks, or other sliding connection. One advantage of the CRL is it takes any ridgeline force as the hammock just hangs under it. Also, once the line is strung between the trees, you can slide the tarp where it’s needed - no need to readjust both ends.
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  5. #15
    Senior Member cmoulder's Avatar
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    Cougarmeat sums up nicely the advantages of CRL as I also see them.

    One thing to remember about shock cord (elastic, bungee) is that once it reaches its limits of stretch it becomes a static cord. As its name implies, it does attenuate the shock loading up to a point, but continuously high winds still stress the tarp edge/binding and the material itself.

    In October of 2018 some friends and I camped at Dolly Sods in WV right about the time Hurricane Michael was exiting the East Coast, leaving a huge pressure gradient in its wake. It was the occasion for the worst beating I've ever given a tarp. The HG Hex .51 DCF was hammered for about 14 hours straight with ~40mph winds gusting occasionally to over 50mph. I used a Zing-it CRL and some 1.18mm Atwood Microcord for the guylines, and shepherd hook stakes. No shock cord. I thought surely it wouldn't survive the battering but I'm still using the same tarp today, just this past weekend in fact.

    Not sure what you mean "what's wrong with a horizontal CRL" ..... If you mean the angle of the CRL after it has been pitched, that might refer to the fact that hammocks are usually set up with the foot end higher than the head end, and for maximum coverage the tarp can be pitched such that its ridge follows the hammock structural ridge line. So in that case the tarp CRL would not end up horizontal.
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  6. #16

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    thanks cmoulder and cougarmeat; i do use a crl usually with nama claws for my tarps. i also appreciate the ability to slide it from one side to the other, and the fact that it takes some pressure off the tarp, especially if the trees move.

    i was asking about horizontal crls because nanok commented "setup problems include improper use of ridgeline (for instance nearly horizontal ridgeline, which unfortunately is very common)" and it's the first time I'd heard that it would be an issue for a tarp

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  7. #17
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    turtle feet, imagine if you will ~ cue Twilight Zone theme ~ the horizontal ridgeline and a less then perfect tarp pitch - say because of a full or partial porch mode setup or just some slack because there’s a big tree root (that you can’t tie to) or rock just where you want to put your stake. Add heavy rain + some wind. So you might get some “swimming pools” developing on your tarp. They are just waiting to gain enough water to dump on your shoes, or you, as your head brushes the tarp. Now ... If you setup that tarp ridgeline at some angle, it is much easier for water to drain off. And if the wind/trees cooperate, you could event tilt the lower end so that it faces the oncoming wind.

    In my mind, these are little finesses. I can’t remember ever purposely angling a tarp ridgeline - though there have been times when I wish I would have. It’s all just a casual, slow-ish learning curve - what works for you. There is a constant trade off between classical knots vs easy to set (and unset) hardware. Thicker cord that’s easier for cold, undexterous, hands to manipulate or thinner (entering the X-Files realm) 1.85 mm guylines.
    In order to see what few have seen, you must go where few have gone. And DO what few have done.

  8. #18
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    Quote Originally Posted by turtlefeet View Post
    thanks cmoulder and cougarmeat; i do use a crl usually with nama claws for my tarps. i also appreciate the ability to slide it from one side to the other, and the fact that it takes some pressure off the tarp, especially if the trees move.

    i was asking about horizontal crls because nanok commented "setup problems include improper use of ridgeline (for instance nearly horizontal ridgeline, which unfortunately is very common)" and it's the first time I'd heard that it would be an issue for a tarp

    Sent from my Pixel 4a (5G) using Tapatalk
    hmm, it seems i created a bit of confusion, sorry for being too vague. i do prefer a continuous ridgeline myself, and i was refering to the "shape" of the ridgeline between the trees, rather than just the portion which goes along the tarp, so i should have said, more unambiguously: horizontal ridgeline tieouts are a problem. the reason is the same as why horizontal (or "too flat") hammock suspension is a bad idea, and that is the physics of how rope is loaded: at a 30 degree angle, you'll get on each side of the suspension the same load as the vertical load applied in the middle (so weight in the hammock, or weight of tarp + guyout pull), as you go flatter than 30, the load on the rope starts to increase very very fast, at 5 degrees you'll end up with nearly a factor of 6 (so for 20kg of pull down on the ridgeline, you'd get a load of nearly 120kg along the ridgeline, and on the tree); the other side effect to this is that you will also get a situation where any vertical movement of the tarp downwards (which only the ridgeline fights against) will further increase the overload, especially if the ridgeline is static (like dyneema), and it will take a lot less force induced by the wind to produce significant vertical movement (as it is comparatively much easier to move the tarp down when the ridgeline tieouts are flat, than when they are angled down, you can easily test this by hand, even without a tarp, just set the same piece of string between two fixed objects, and see how easy it is to force the middle down from the "taut" position, when the line has a 30 degree sag, for instance, compared to when it is stretched between the tow attachement points almost horizonatally -- just make sure you tart out with roughly the same tension in both cases, otherwise the test will be very misleading).

    another way to look at this: if you want to efficiently use the strength of the line, and the strength of the attachement points, and obtain a roof which is stable under wind loads, think of the difference between having a nice symmetrical pyramid, formed by the corner tieouts and the ridgeline tieout, on each side, compared to having the ridgeline tieout "horizontal", and thus having virtually no downward vertical support (the corner tieouts, if setup well, will stop the tarp from going up, but the ridgeline will have a lot of trouble stopping the tarp from going down, so you'll get a inbalanced system, and the tarp flapping still); this is why, as a consequence, people overtighten the ridgeline, to provide some vertical support at this unreasonable angle, with various potential side effects: damage to trees, use of dyneema (cause if the ridgeline stretches, you'll never be able to tighten it enough at such angles -- would be fine at normal angles), and hence more damage, damage to the tarp when a split ridgeline is used, and, of course, wonderful mechanical advantage ratcheting systems to tighten the ridgeline. to add insult to injury, because of this practice of attaching the ridgeline much lower than the hammock suspension, the two suspension systems tend to interfere, so there's all kinds of methods and discussions as to how to minimize this interference, which wouldn't be necessary at all, if the tarp ridgeline was attached "where it belongs" (TM, imho), which is ideally on the hammock tree straps (so no need to go around the tree again), or at least above them, but not below.

    i have been experimenting and trying to figure out what i might be missing, for the past few years, but i still don't get it, imho what i called the "levitating tarp" method, in one of my previous threads, is just the reasonable way to do it (but i am happy to hear what disadvantages/downsides people see with it, of course)

  9. #19

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    ok, I'll try that out-- i doubt I'll be attaching to the hammock straps much, since the bridge hang angle is already really low, and the one time i tried to use that method in a GE it felt like the tarp was so loosey goosey given that the tarp tension changes when i get in the hammock. may be you can give me some pointers there.

    but i will try to have a higher tree attachment point for the crl and let it sag more rather than tighten it up (it's true, i do usually use jeff myers' toggle method to obtain a mechanical advantage on the crl and subsequently tie it off - for that matter i also use trucker's hitches on my corner tie outs using dyneema cordage, no hardware, so maybe I'm just over tightening with cordage that's too strong?)



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  10. #20
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    aah, bridge hammock. i didn't play with those, that's a bit different indeed, but the concept for the tarp remains valid: as you said, you don't need to change much to try it, just attach higher on the tree (the farther apart the trees, the higher you'd want to go, similar to rigging up a gathered end hammock), and leave the ridgeline "slack" to begin with, tighten fully only after tightening, or at least securing, the corner tieouts; this method will work even with a dyneema ridgeline (no stretch), but a stretchy ridgeline will be a lot more forgiving and easy to work with, as explained in the thread linked above, as it will allow to lightly tension the ridgeline, and then adjust the position of the tarp using the corner guylines, making for a very verastile, and easy to adjust setup, even adjustable under the assault of heavy winds, without fully losing tension in the tarp, and having to deal with "shock loads" etc.

    mechanical advantage with truckers hitches and such: hey, don't get me wrong, i'm a big fan of mechanical advantage, especially without hardware, all i'm saying is be careful with mechanical advantage and lightweight tarps (basically, all our camping tarps), you can tighten them alright, but you can also easily overtighten them, and as you noted, if the guylines/ridgeline are static and strong (like dyneema or kevlar lines, for instance), then there won't be much room for "automagic adjustment", so rigging it carefully, and thinking about angles and such, becomes even more critical, when using dyneema. i do like dyneema a lot, and i will probably play with it more for use with tarps as well, but so far, i find myself inclined to recommend to anyone to at least not be too "judgemental" of the more pedestrian, and cheaper, nylon lines and such, with their stretch and other downfalls (some of which might, in fact, be advantages); btw, i've also started playing with pp (polypropylene) line, which is becoming more and more available, in various sizes (and colors! proper colors, not painted on, like dyneema), often in braids which are easily spliceable; the good quality one is getting nearly as strong as nylon in the same size (which is plenty for tarps), is even lighter than dyneema, and is very cheap (cheaper than nylon lines), it's also very hydrophobic (basically like dyneema in that respect), so has all the advantages of dyneema, lacks only the "golden fleece price" and the "magical strength", both of which i'll gladly do away with for tarp purposes. ah, and in regards to knots, it tends to hold them fine, it can be a bit slippery compared to nylon and such, but it lacks the magic, self lubricating qualities of dyneema, which is nice, as it makes it useable with knots too, not only spliced (retains decent strength when knotted, doesn't require specially designed knots to avoid slipping)

    regarding the tarp sagging when loading a "flat hang angle" hammock: this will typically happen if the tarp is attached on the hammock suspension, not at the tree (if you attach to the tree straps, or very close to the tree, this won't be much of a problem), and it will happen with line which has no stretch: when you get in the hammock and load the system, the hang angle will significantly increase (because of the physics i was describing above: the angle is shallow, so the loads in the suspension and hammock are multiplied, thus there's more stretch, which will change the hang angle, until an equilibrium is reached); if the tarp ridgeline is attached, for instance, somewhere in the middle of the suspension (between tree and hammock), then with the stretch and change in angle that ensues, the two attachment points will endup closer together, even if not by much, and because dyneema stretches basically none under the loads which a tarp puts on it (because we use hugely oversized dyneema line for tarp ridgelines, otherwise it would be unconfortable to handle -- i have some 1mm dyneema which is rated for 200kgf break strength, that's still too strong, and 1mm is torture already to deal with by hand, especially in the cold), then even a few millimeters of movement will change the tension in the ridgeline to basically zero, resulting in a saggy tarp; the solution is to attach at the tree, or use a ridgeline made of something which will allow you to store some ellastic deformation (like nylon, which everybody seems to recommend against for tarp ridgelines ...because it's stretchy), this way, when the tarp moves, because of wind or suspension movements or what not, the ridgeline will not immediately lose all tension after a few mm of offset, but instead it will "adapt" and stay in varying degrees of tautness, hence avoiding spectacularly flapping tarp shows.

    interestingly, depending on how you rig things, on a gathered end hammock, with a structural ridgeline that's "reliable" (so doesn't change dimension under load, like dyneema -- one very good use for dyneema, btw), if the hammock is rigged such that the structural ridgeline does take some of the load (so, the suspension angle is shallower than the gang angle set by the SRL on the hammock), then aside from attaching the tarp ridgeline at the trees, attaching it at the hammock ends (so very close, or at the SRL ends), will also result in no change in tarp tension, when the hammock is loaded (or, for most intents and purposes, will most like cause the tarp to tighten up a bit when loading the hammock), this is handy to know, if you need it in a pinch, i personally don't use this much, as it comes with the disadvantage the tarp will endup being in "storm mode" (as close as it goes to the hammock), and the only way to ellevate it would be re-rigging

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