How bad are knots in Dyneema?
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- Опубліковано 27 січ 2025
- You are supposed to splice Dyneema to retain most of its strength. What happens if you tie a figure 8 in it?
Our Results with Sk75 Dyneema with figure 8s:
3mm - 4.06kN (MBS 10.2kN)
4mm - 8.86kN (MBS 21.8kN)
6mm - 12.93kN (MBS 34.25kN)
8mm - 20.77kN (MBS 54.7kN)
Our main channel is @HowNOT2
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Just for those that are wondering, Dyneema is a brand name. The name of the material Dyneema is made out of is UHMWPE. Spectra is also a brand name made out of the same material.
Similar material, not the same. They are produced by different companies.
@@CanyoneeringUSA most people use "same material" to mean rough composition not manufacture.
I use a supermunter or munter with an extra loop, on a light d-shaped screw gate. Longest rap was 150' doublestrand 1/8". I use small quicklinks instead of knots between spliced eyes, to connect ropes. I definitely use warpspeed II, because I can also ascend it with spyderline schwabisch knots. That's what I'm doing in profile pic.
Fast, simple and task oriented informative video. I liked it.
I would love to see another video, or a series, looking at rappelling on different materials. The setup you used to look at different canyoning descenders was brilliant.
Yes short is good! cheers
I'm impressed that the knots broke and didnt just slip.
Rapping on the 3mm, I’d be more concerned with heat or pancaking, than the knot. Imagine the pucker factor if you had to stop along the way down - the visions of your descender sizzling through the cord and then that last backward free fall you would ever do….
I hate my imagination.
I don't think they are rappelling on the 3mm, but rather using it to make a rappel anchor so they can retrieve their climbing rope. At least that was my assumption based on what he read.
Maybe, but at 1.02 Ryan talks about being able to get enough friction to stop sliding right down the rope.
In any event, I’d still opt for a heavier load 😊
I have pulled doublestrand 1/8" amsteel 80' through a supermunter on an attache carabiner, 250 lbs average for to 3 seconds it took. When the simulated rap stopped, I brought the load up and the hot biner sat with unmoving amsteel at 400 lbs tension for 100s. No melting
Nice video. I must say I like them short and to the point, which you've done. Unless I had done *a lot* of practice abseiling on 3mm anything, I'd activate an EPIRB before I tried it for the first time at height! :)
EPIRB ????????????? Why do people act like or assume that any string of letters used as an abbreviation for some thing or process is immediately understandable by everyone or anyone that might read their post???? Your comment is meaningless to anyone who is not "initiated" into your 'club'/'cult'/'gang'. I've watch dozens of How NOT 2 videos and never saw/heard this epirb used or defined. So WTF??
Awesome man! I was also wondering about this.
One other issue w/ rappelling with dyneema is it starts to lose strength _quickly_ when it's heated up. IIRC I think it starts losing strength around 120 degrees f, which given ambient air plus the friction of a rappelling device could hit quickly.
Source? I think it's more like 70-80C.
In short yes dyneema is way more than adequately strong enough. Im curious though about how rappelling devices and rope grabs act with its different almost waxy sheen. Polyester grabs very different than nylon
In general a knot cuts the strength of any line in half.
A proper finger-trap with tapered tails the right length can yield 100% of the line strength.
What about the knot on the end of a soft shackle? Or Ester knots? All knots on dyneema.
Would/could you test termination knots with a couple extra wraps around the carabineer so it's more like a friction anchor? Might be a way to get a bit more of the strength out of it.
Short form good. Long form good too. But nice to have a mix. I don't always feel like long form. Probably always feel like short form.
Looking for information on spectra twine
Lol this video just caused me to get someone to pull their 4mm blue rope out of their kit.. He kept it as a backups backup and shit himself looking at this. Thank goodness he never used it for his intended purposes.
It could be good to use as a pull cord if you tie a blocker knot at the rappel station and use the entire length of a normal rope, then pull it down with the pull cord. I just wouldn't willy nilly be rappelling on something so tiny all on it's own.
I thought dyneema can’t handle heat from the friction of a rappel?
Is it safe to leave knots permanently tied in on dyneema? Like for an anchor. I leave knots in mine, never bother untying it, but I worry that constant loads on the same knot will cause issues in the long run even though I have no evidence to support that fear
Long is good too of course
I was pleased to see that a figure 8, knot will break rather than slip. I always thought that every knot in dyneema would simply untie itself by slipping rather than break.
So, basically 40% strenght rdtained.
How about testing some knots designed to hold in dyneema? ua-cam.com/video/b9GLp1Esins/v-deo.html
These are from one of the innovators of soft shackles for sailing
i was about to ask the same question, with the same example 😄
Double loop/Super 8 seems to hold better than figure 8 in dyneema too
People were honestly rapping on 3mm?! Not pull cording?
Bail gear, the idea is that it weighs little enough to justify bringing, and could save you if you've got no better options. There are ways even with a grirgi to add a ton of friction. Might work in something like this. Idk if I'd use it
4mm ffs.
Enjoyed the video and learned the "40% strength retained" rule of thumb for Dyneema--useful info.
But come on, kN? Seems apt if you're measuring, I dunno, asteroid impact effects on Jupiter, but bro inches and pounds for Earthlings, please.
Wait I'm confused, you aren't supposed to tie knots with it? How is a rope useful without tieing knots in it?
Every time you use it you have to splice it? I bet it just won't get used much then
you'd be surprised 😂
@@zoladkow I am surprised!
Think the short format works against the nature of this channel.
I'd rather just have the longer format with methodology and background.
Don't like shorts.
No scientist would EVER base a theory on the results of ONE experiment. You even proved your results to be invalid by your own words when you said the results would be all over the place for multiple trials.
This is my sub channel where I post quickies, my main channel we do more testing and try to be more thorough. We were just curious if 3mm would break below 1kN which it didn't and we chased the rabbit to see what the other diameters would do. You assume this is the only test I've ever done. I've done thousands to know we weren't getting an outlier and try to make these short and sweet. I also give the disclaimer that 1 test isn't a full picture. Chill out.
How about you donate a couple hundred to finance these samples?
Do you even know how expensive these materials are?
Be a little thankful for what you get for free.
All science is anecdotal, some is just really high quality anecdotal. The tests proved a very useful “x can break at y kN”
@@HowNOT2 Again chasing a rabbit down a hole means to follow a path that leads you into confusing, disorienting and illogical situations, just like Alice (I assume you HAVE heard of "Alice in Wonderland"). I hear people like you butcher the language every day, and your recalcitrance at educating yourself irritates me. Rather than say "chill out" try learning to speak the language correctly.
@@largeformatlandscape Science is not anecdotal.
Anecdotal definition. Not necessarily true or reliable, because it is based on personal accounts RATHER THAN FACTS OR RESEARCH.
Dude you’re a male, your acting funny like a female. Gay much?
Call me old or old fashion & live by the simple rule of “when in Rome,,,” & in America we still use the standard system of measuring not the metric system. So you sir get a dislike for being a “European wannabe!” Had you talked about your measurements in foot pounds, you would had my respect. I hate to go negative but if I have to look up your units of measurement to translate them then what good is your video in comparison to others?
Whatever metric I use I piss someone off. KN is a measurement of force that is more universal than kgf or lbf and youtube is global not just an American thing. Get over it.
Call me old fashioned but the US is on its own using ‘freedumb’ units - and as this audience is truly international it would be stoopid to play to the minority.
BTW your military uses metric to fit in with the majority, why don’t the rest of you?
You realise that youtube is not america, right ?
People all over the globe watch youtube channels.
Using international system units (which is not just used in europe, but pretty much every country apart from america, and a couple other) is just being nice with worldwide audience !
Bro, US military measures in SI units, doesn’t it? How many “clicks” is you head shoved up your rear?
Beyond that, in the US, most of the gear he is testing is rated in KN, so he is making everyone’s life easier by using the same units that the product is native to.
In engineering, and science in general, best practice is to only convert units after the math work is done.
And anyway, he does all this is the mainline channel. What’s your problem?
Do you even climb?
Be careful what you wish for. You may get a video with diameters in feet, and tensile strengths in foot pounds, which makes no sense because that is a unit of torque.