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  1. #31
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    Quote Originally Posted by Daibhead View Post
    Ok so I was messing with a scrap of amsteel and created exactly what you’ve described, then read your comment a couple days later. Armed with the assurance that others have created these fast shackles as well, I’ve been using them in my suspension. Turns out I do, in fact, enjoy soft shackles if a double overhand knot is sufficient. I also happened to come across an article by a caver who has break-tested double overhand knots, and the knot itself is at least as strong as the cord used to tie it. So hey, works for me!
    (...)
    glad you're enjoying them

    just to make sure some things are clear:

    - the double overhand in dyneema has not been tested that i know of, but based on all the other knots that have been, it is expected to slide out at very marginal loads (probably somewhere around 20% line strength). the test you have found might be interesting, but you need to make sure what material they are made with: there's a huge difference, in terms of behavior with knots, between dyneema and basically anything else out there. for instance the good old bowline will slide at very low loads (under 20% iirc), it only does that in dyneema.

    - this design you are using is not inherently secure, so be careful. the double overhand also has the disadvantage (compared to the button knot normally used) that it doesn't have a shape that helps as much with retention. this combined with having a "loose" capture loop means you will have to be really careful with these things, and always double check them before loading them etc

    - i don't think anyone break tested this design, if you know otherwise, i'd be very interested in a link to their results.

    good news is, there is a much better way (actually, two) to make a stopper knot for a softshackle, without having to learn how to tie the button knot, and this way is almost as simple as tieing a double overhand on a backsplice, but the shape is better (so more secure), and it has been break tested to be strong enough that it is not the weak point of current softshackle designs (so as good as the button knot for the purpose). the method is based on making a splice loop and then putting it through itself (so basically an overhand stopper on a backsplice, one might say, but made in such a way that it's much more safe from sliding open, and it also has no tail sticking out), and alternative method, which results in an even larger stopper, is based on making the small spliced loop, actually making an overhand and then locking it with the spliced loop (i don't like this one because of the difficulty to properly pull it tight)

    i am a big fan of softshackles and innovative ones at that, but please be sure you are aware what are the known facts when playing with them, especially for suspending a human. not all soft shackles are created (or designed) equal, and small differences can have a big impact. i don't mean it as discouragement, just be aware

  2. #32
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    Quote Originally Posted by jadekayak View Post
    Sorry but there is no such thing as a "metric tones"
    The correct word would be "tonnes" and calling it a "metric tonne" is an oxymoron.

    A "tonne" is automatically METRIC.

    on the other had thete is an imperial ton, and the US variants-short ton,long ton and standard ton-all of which are slightly different weights.

    A tonne is exactly the same weight no matter what-1000kg.


    Have said that its still a fair amount of breaking strain for hammocking.

    I always use 3mm dyneema sk75/78 rated to 1000kg.
    thank you, that's very interesting and good to know (i never know which spelling is the right one in some cases, and this is one of them)

    calling it metric helps to remove ambiguity (even if the spelling is not right, or the context is not clear, etc), although strictly speaking it might look silly, i think it does help with avoiding confusion. in other words, pleonasms probably exist mainly for disambiguation in common speach, and they sometimes are effective for that

    i use 3mm sk78 as well (the one i use is rated at 950daN, which is just a bit short of the full tonne), i think it's the perfect balance between lightweight, comfortable safety factor, and ease of handling (as it gets thinner, it gets unpleasant quickly)

  3. #33
    Senior Member jadekayak's Avatar
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    [QUOTE=nanok;2062607

    i use 3mm sk78 as well (the one i use is rated at 950daN, which is just a bit short of the full tonne), [/QUOTE]


    I have noticed that as well.

    Both sk75 and 78 come in two ratings


    I always get the higher.
    Im picking up 10m of GREEN sk78 as soon as we are out of lvl3 lockdown in hopefully 1 more week.

    I also have some 2mm stuff for my tarp that i havent used yet.
    Tried it for main suspension but it snapped,and it had about 500kg breaking strain.

    This is my 7 month stealth hang in the south island of New Zealand(went gold mining)

    OzTrail tarp,homemade hammock and bugnet,inflatable pad with a 1/3 sized pad sideways for my shoulders.
    I used my 24 yearold down sleeping bag as a quilt.

    I dont know why the photo ended upside down!
    Attached Images Attached Images

  4. #34
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    i did a bit of research and analysis regarding the rated mbs vs the "diameter", in another thread here you might have seen. it's quite boring and tedious, but i think the conclusion is somewhat useful (and probably not incorrect):

    - stated line diameter should be taken as a rough estimate, not a characteristic of the line, there's too many things influencing it. it just gives an idea of how it will feel to handle the line when unloaded, but that's about it. trying to correlate it with expected strength etc is an exercise in confusion
    - the interesting parameter to look out for is mass per length, and it makes a lot more sense to correlate that to MBS, than diameter
    - the differences in MBS is a real thing, in relation to mass/length, and i think it is useful to keep track of it when shopping for dyneema
    - at this point, my working theory regarding differences of MBS for similar mass/length is that they are explained by the angle of the braiding. basically, the tighter the braid, the less strength is retained. i think this is why the samson amsteel is significantly weaker than the liros dyneema i'm using, and also why making whoopie slings and UCR that work out of the samson is much much easier than out of what i'm using.

    (to give you an idea of how much fun this was to figure out:

    liros, 3mm (aka 1/8in): 950daN, 460g/100m
    amsteel, 1/8in: 1134daN, 774g/100m
    amsteel, 7/64in (~2.7mm): 725daN, 446g/100m
    )

    i know people sometimes use (with some "success") thin dyneema line with ratings in the 500kg range, i personally don't like that at all, i consider a 10:1 safety factor the ideal minimum. i did use some 2.2mm line rated just under 500kg briefly, and it worked, but i consider it a bad idea, unless one weighs 50kg (but even then, the weight savings are marginal, and the disconfort of dealing with such thin line makes it not worth it imho). i do find it surprising that it snapped though, was it after prolongued use? or was it a very "flat" hang (very small hang angle)?

    i'd have to get my hands on some amsteel, do some comparative measurements of the braid angle, and ideally also do some break tests for both lines (to eliminate the possibility that the methods used to estimate the mbs rating are introducing some of the difference). taking measurements of the braid would also enable me to calculate what should be, theorethically, the loss in strength between the two, assuming my theory is correct, so that could be quite interesting to see if it validates. i have yet to see any amsteel in person, unfortunately.

    newzeeland is one of my top destinations on this planet, i hope some day i will manage to spend some time there. i honestly think it is really special, as close to "heaven" as i can imagine (large expanses of untouched nature, and very diverse life, and all kinds of geography one might want, including some superb mountains, which is my favourite kind of place to be). enjoy it a bit extra, for those of us who might never have the chance.

  5. #35
    Senior Member jadekayak's Avatar
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    That is an interesting study.

    It would explain why there is a difference in breaking strains on different brands of the same diameter.

    The dyneema im using is from amare in italy.

    Both the sk75 and 78 are super round 12 strand braid.
    It is not a really tight braid but not that open either.

    I have noticed flucuatiins in diameter though.


    My 2mm that broke was just below the spliced eyeand was a std hangle of 30į plus/minus a little.

    I use a longer bury and no locked brummel.

    On my dyneema now i also stitch the bury shut under tension so ut doesnt accidently loosen-not structural stitching-just holding it closed.
    I suppose whipping would do a better job but i dont like it much

  6. #36
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    Quote Originally Posted by jadekayak View Post
    That is an interesting study.

    It would explain why there is a difference in breaking strains on different brands of the same diameter.

    The dyneema im using is from amare in italy.

    Both the sk75 and 78 are super round 12 strand braid.
    It is not a really tight braid but not that open either.
    yeah. my explanation looks promising, as in terms of physics it is very straightforward: textile fibers are strong inline, by comparison, the strength in the perpendicular directions to the "lenghtwise" is insignificant for most fibers. so unbraided fibers will always have the best strength, and the least stretch. the tighter you braid, the more stretchability you introduce (even if some of it is permanent), and the more strength you lose through distributing force in any direction which is not lengthwise, and thus applying significant shearing forces of the strands on eachother.

    at least, it sounds it might be so. i have yet to validate this through proper testing

    I have noticed flucuatiins in diameter though.
    yeah, it's really a bit of a ghost, diameter, it's even difficult to measure. one should measure under load (how much load?) and then if you measure with calipers, how much force should you apply across the strands before you call it "the measurement", there's way too many factors when trying to measure diameter with any precision. if you say "around 3mm, which could mean 2.8, 3.2 etc" that's one thing, but if you expect 3.1mm to be 3.15 or 3.16 at most, down to 3.07 or such, you can basically forget about it with rope, unless we devise a very repeatable standard, based on a complicated rig that would tension the rope to a chosen percentage of mbs, measure lateral forces too, take readings at different points along a sample length, etc. and in the end it's pointless, mass/100m is much better, easier to measure, and more accurate with very simple tools everyone has at their disposal.

    My 2mm that broke was just below the spliced eyeand was a std hangle of 30į plus/minus a little.
    that's intriguing. the only thing i can think of is that the end of the bury was not tapered, but as far as i recall, from the extensive studies i read about regarding short tapers and even no tapers and how they influence strength, it should not go much worse than about 60% of rated strength (even with no taper), but perhaps i misremember. even 60% of 500kgf should still be ok at a reasonable hangle, but it's true it gets a bit too close for comfort, especially for full sized humans that might near 100kg or so (and with movement and such, you can easily reach double that on the suspension, temporarily)

    I use a longer bury and no locked brummel.

    On my dyneema now i also stitch the bury shut under tension so ut doesnt accidently loosen-not structural stitching-just holding it closed.
    I suppose whipping would do a better job but i dont like it much
    no brummel is wise choice, imho the locked brummel is a bit of a mistake (but that's another can of worms). no brummel, long bury and stitched is definitely the strongest solution (assuming the bury is carefully tapered, otherwise the transition becomes the weak point)

    i think stitching is the best way to go, again, based on what i've seen and read, and my own anecdotal experiments, whipping is not better for this purpose (it's prettier, yeah, but stitching is better to hold a splice in place)

    it sounds to me like you're doing things by the book (i mean, pro book), assuming you're using a long "patient" taper (the tapering of the bury is basically the most tedious part of making a simple splice, so many people take shortcuts, unfortunately it is also the most common weakness and cause of "premature" failure)

  7. #37
    Senior Member jadekayak's Avatar
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    I DO use a taper-and almost as long as the bury.

    And yes,its tedious doing that but its only twice as long ,which is 6mins instead of 3.

    The stitching takes most of the time.

    Maybe spectra would be better-unbraided uhmwpe with a polyester core.
    You just need to upsize so the uhmwpe is the same rating as rhe dyneema braid you would normall use.

    3mm sk78 would need to become 4.something,maybe even 6mm spectra.

    The weight difference would be harsh too.

    Polyester is much heavier than uhmwpe

  8. #38
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    Continuous ridgeline for hammock (not for tarp)

    I made a fixed length hammock ridgeline.
    Using 1/8 amsteel, made an eye splice on each end.
    Lazy manís way
    No locked brummell
    No sewing
    The spliced buries on each end are about 18 inches long
    The taper is about an inch to an inch and a half long

    After adjusting length real close to desired length of ridgeline.
    Milked the bury and tied an overhand knot about middle of buriesí length.
    Tightened overhand knot real tight
    Milked buries again
    And set the buries and the knots by hanging my body weight from almost finished ridgeline

    Then set up hammock with a slightly tight ridgeline and finished curing or setting the overhand knot and buried splice.

    Itís going nowhere!

    The overhand knot keeps the end eye splice loops from changing size during packing and storage

    The overhand knot keeps the inner part of splice from moving in either direction.
    With 1/8 amsteel, itís probably stronger than Iíll ever need.

    Will it break from destructive testing?
    Yes!
    But so will sewn stitching, as well as locked brummell

    Overhand knot just ainít pretty
    It is easier than locked brummel,to get very close to desired length of hammock ridgeline. This helps, especially when I use overlong buries. Itís hard to know in advance, how this will affect length of finished hammock ridgeline.

    Sewing or stitching the splice, can get a very accurate final length, more accurate than my overhand knot.
    Sewing or stitching is probably the best way to get a fixed length hammock ridgeline.
    I chose a shortcut that ďworks for meĒ
    Last edited by Phantom Grappler; 09-27-2021 at 13:32.

  9. #39
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    Quote Originally Posted by jadekayak View Post
    I DO use a taper-and almost as long as the bury.

    And yes,its tedious doing that but its only twice as long ,which is 6mins instead of 3.

    The stitching takes most of the time.

    Maybe spectra would be better-unbraided uhmwpe with a polyester core.
    You just need to upsize so the uhmwpe is the same rating as rhe dyneema braid you would normall use.

    3mm sk78 would need to become 4.something,maybe even 6mm spectra.

    The weight difference would be harsh too.

    Polyester is much heavier than uhmwpe
    it sounds perfect though. i don't think there is stronger or more reliable solution, the failure you mentioned must have been due to unnoticed damage, or some other "freak factor" (and that's one reason why i "insist" on 10:1 safety factor, to allow for some room for "unnoticed unexpected factors")

    with mixed braids, not only you need to upsize and endup with a heavier line, but usually the sheathing will slide on the core, when the core is dyneema it always will, and as both polyester and nylon will stretch much more much earlier than dyneema, what ends up happening is that the sheathing fails before putting much strain on the dyneema core, and then the whole thing slides apart (especially true for knots)

    i've looked at various options, and it seems that, at least for now, unsheathed single braided dyneema, and splicing skills, are the best overall option. aside from tracers and such, braiding anything with dyneema won't add anything good, and braiding anything around it adds weight and not much more.

  10. #40
    Senior Member jadekayak's Avatar
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    I screwed up on description of spectra-,it is a dyneema core with polyester sheathing.

    I had not thought of the slippage factor.
    Yachties swear by the stuff.

    I also prefer the 10◊ safety factor and have received a minor bollicking on here regarding this.

    I hang in dangerous places-dangerous to fall

    If the fall doesnt kill you it will leave you mangled and crippled for life(which is worse to me)

    I hang up trees and on rock faces.

    I only use the light dyneema for my tarp now.

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