if "any knot will do" why use amsteel/dyneema at all? i mean, it's not like the colors are nice.
a lot of these "big enough" knots fail at trivial loads, in some cases as low as 10% line strength or thereabouts, so if you don't like to do it properly, why not use paracord instead? the result will be stronger (with whichever stopper knot you can find on animated knots, basically), it's cheaper, and comes in more colors. the slight stretch for such short lengths is even a bonus, a little bit of shock absorption can be good for ones health.
the solutions which work in dyneema/uhmwpe and have been properly tested are: diamond knot (but not ideal, not recommended), bryon toss button knot (which was designed for this, still the best solution), or "spliced big overheand" (probably the easiest solution which is both safe and strong, but depending on the method used it might require a winch to set it, before it is truly safe, and the result tends to be a rather big button, which is fine if you like that -- i know i do for some applications)
this is talking about soft shackles. if you're talking about loops with no capture mechanism (as it appears might be the case?) then all bets are off, anyway, i guess.
Last edited by nanok; 05-19-2023 at 05:49.
Nanok, my guess is paracord is not used because it ssssstttttttrrrrrreeeeccccchhhhhheeeeesssss. However, I do get that we are not talking about clothesline length cord runs. I think there's a "tidiness" factor in being able to weave a finished product (no loose frayed ends). And there's the high strength factor that can be compromised by a knot/twist/bend and still give a large margin of safety. Color might be an issue, but it's the last thing I think about - unless I want to purposely mark something - "Red at the head".
In order to see what few have seen, you must go where few have gone. And DO what few have done.
yeah, i don't know why we're so scared of the stretch, at those lengths it is inconsequential, or even handy.
what worries me is the safety factor idea, what is that based on? who tested "whatever knot" in dyneema and can quote the numbers? (actually, test were done, and even posted on this forum, but we seem to forget).
apart from the specialized well known and tested stopper knots used for dyneema softshackles, one can assume, as a rule of thumb, that a dyneema shackle will be about half as strong as a similar paracord one, and sadly that's already too weak to be safe for supporting a human. is it possible that the incredible line strength of dyneema gives us a false sense of safety, and we forget that some knots and configurations really don't work in this material? if i cannot find data of destruction testing of a certain knot or configuration in dyneema, i am not ok to recommend it to anyone for any use, let alone human load. and yes, i did do the research, and there is data out there, which is consistent, and shows how low loads particular knots withstand in dyneema (including the good old ashley stopper for instance), so it's not just plain paranoia.
please be safe.
Last edited by nanok; 05-19-2023 at 16:17.
Nanok,
Where are getting these numbers for paracord??
Ambulo tua ambulo.
hi gargoyle,
i don't have the numbers from testing of softshackles in paracord, as i don't think anybody bothered tbh (i did some testing myself, some time ago when i was developing some new designs, but i don't have a dyno to take measurements)
however, paracord has the advantage of being "boring" with how it handles knots (that is to say, nylon fibers are, they are "within the range we expect); 50% strength is a very pessimistic estimate, i think even the sheet bend does better. more realistic is around 75% strength retained, with most "decent" knots. proper testing would still be nice, as there are other factors involved (like the capture noose). with dyneema, we know it ranges from "you have got to be kidding" - 10% or under, for most knots, especially "simple" ones, to 50% at best, for a very small handful of knots (the estar hitch and stopper knot invented for it, the toss shackle button knot ); we know the noose fails above 50%, only when using the button knot, if using the diamond knot, the knot will fail first.
here's some "napkin calculations" to get an idea
paracord 550 (550lbs force rated, or 250dan/kgf roughly)
amsteel 1/8 (about 1000daN, depending which rating you take)
amsteel 7/64 (more commonly used here, i think, 725daN)
in daN (tens of newtons, close to kg force)
1/8 amsteel
1000*4*.1
400.0
7/64 amsteel
725*4*.1
290.0
paracord 550 (pessimistic)
250*4*.5
500.0
paracord 550 (more realistic)
250*4*.75
750.00
even a pessimistic estimate is stronger than even 1/8 amsteel with an "unknown knot". of course, we know that if using a decent knot, we get in excess of 2KN (2 metric tons force, or 4400lbs force). and if we use an "unknown" knot, we might get anywhere from 5-10% to about 50%, we just won't know until we break test it, and the range is huge. to make matters much worse, with dyneema a meager 10%, as you see above, is still a bit above the typical load a hammock suspension will see, so when you hear "it works fine for me" it actually still means we don't know. dyneema also doesn't "give signs", it does not stretch like other fibers, for instance, so when you're approaching the limits of the setup, you'll perceive no change until it actually fails.
are these estimates to be taken as gospel? definitely not, but we do know that predicting what dyneema will do, when knots are involved, is extremely hard still, while with nylon fibers the range of what will happen is a lot more limited, so more predictable.
i'm a big fan of dyneema/uhmwpe, don't get me wrong. i'm just reminding it matters a lot what knots we use and how.
I work in the heavy lift industry. 100,000 pound objects suspended from Amsteel and steel cables. Tugboats are now fitted with Amsteel, towing 500 ton+ ships.
When the Pros switch over to paracord, I’ll let you know.
Ambulo tua ambulo.
yeah, i know it can be quite difficult to follow. especially with so many numbers. i did try to make it as accessible as possible, was there something in particular that you could use help processing?
Here’s a good test for ya at home.
Hang a 20 pound weight on loops. One paracord and one Amsteel. Measure immediately the length and leave them to hang for a day or three. Measure again.
Now wet thru the loops, weight still hanging. Measure again in a few hours.
Paracord vs Amsteel debates are seriously overdone. I used paracord years ago. It was kinda the only thing available. It works. But in use the tarp would sag, you readjust, a few hours later the tarp is sagging. Readjust.
You get the picture. Is it the end of the world ?? No.
But in the archives here, the quest for a better, less stretchy, less of a PITA cordage were sought.
So, when better products came along, we quickly spread the word here. They dozens if not more, ropes and cords tried and tested. I got a drawer full… Plain and simple a 100 ft length of zing it vs the same length of paracord is less bulky. In terms of backpacking, volume, weight, durability, and ease of use (less fiddling) are always important. When I first refitted my tarps, piled up all the scrapped paracord, the new string made sense to me.
Paracord makes a great bracelet…
Use it if you like.
I now return everyone to the original topic…EVO LOOPS.
Ambulo tua ambulo.
"Paracord vs Amsteel debates are seriously overdone."
if you say so, i haven't seen any myself, i didn't think anyone would consider debating it until you started to. why did you, if you think they are overdone, btw?
anyway, i noticed people generally despise paracord on here, hence my point: you wouldn't use a paracord softshackle for suspension, but you're happy to use an amsteel softshackle which is so badly constructed that it is potentially worse than a paracord version. i hoped it would be good enough reason to stop and reconsider, for some at least. i see paracord is a bit (more) of a sensitive subject than one might expect, for some.
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