Shockloading Highlines is a Myth - more human testing

[@HowNOT2]

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[@31fourever]

Goes on about the nicely done rigging, unclipped, back to edge. Comfortably kills. Love all the videos, im hooked. You’ve taught me a lot, very much appreciated.

[@PeregrineBF]

SEIT teaches STRADS (Solid, Timely, Redundant, Angle, Distributoion, Simple) instead of EARNESTA or SERENE. They found that equalization is nearly impossible in practice (as you've seen) and that shock loading (and thus No Extension) isn't a major factor. Two sliding-X slings is fine.

[@semjonborzutzki9907]

I think the pre stretch of the webbing because of your weight, compensates the extension when the bolt blows in the first moments. Like that you don't really get a high shock loading peak, since the bolt gets wighted before you fall. And when you start to fall, the webbing already compensated the slack and you don't get much higher forces than with bouncing. That effect would be gone with shorter or more static lines and we should notice, that we most often stand on the line, which means that the distance you fall is higher and you would fall just in just one bolt

[@tehrater480]

My conclusion: If you can take a leash fall, it can take a "shock load"! ~6Kn total when whipping on two bolts ~6Kn when "shock loading" ~4kn total force with his weight static on the line ~2Kn total force with no weight on line IMO: "shock loading" a dynamic system is fine! It's roughly the same as a regular fall on that same dynamic system. Shock loading is only really a problem in static systems, such as very short mid/high/longlines using low-stretch webbing, or when using a static sling/rope as fall protection. But in that kind of scenario, taking a you don't want the system to catch you! Short mid/highlines are a bad idea especially with low stretch webbing.

[@Kravch96]

I think the concern with shock loading is heating up dyneema enough that it melts from friction. Apparently melting point is just 227 F which intuitively doesnt feel that unreachable during a shockload on a sliding x, where dyneema would slide against itself and create a lot of friction

[@pierreostergren3241]

So cool experiment dude. Love from Sweden

[@matscarensio1940]

Love your channel! If you're looking for tests to do there are some related to rope soloing that would definitely be of interest to that community. Currently much of the methods and setups are more based off a gut feeling than science. Some examples: When lead soloing, how much would a fall absorber (such as Kong KISA, a screamer or weighted bag) in the ground anchor lessen the impulse force on the pro and leader? How much does just clipping biners vis-a-vis quickdraws worsen the impulse force? How much worse is a fall when rebelaying the rope halfway up a wall? How much worse is a fall on a fixed ground anchor compared to having a belayer?

[@weikemp]

I would also be very interested in rope solo safety testing.

[@jakeduggan2394]

Would also love rope solo stuff!

[@takk825]

Would the 3 slings in a sliding x and all overlapping create an opportunity for abrasion between the slings under the cyclical loading that can happen when the wind blows across a long highline?

[@chrismuntean]

Hmm maybe? There might be enough force on the slings so they are tensioned and do not move.

[@Erik-vr2uu]

Dynema slings are super slippery and don't have much abrasion on eachother unless there is dirt on them, but anchors made out of other materials might have other challenges

[@iancameron6457]

I definitely would rig like this. It's a bomber setup on two good bolts and three slings. Just too bad it really has to be the right anchor setup to use it. I'd love to not have to carry in static rope or spannies but sadly it's rare for me to find a spot that it would be viable.

[@tomenright9]

Hey thanks for the video! I have a question. For clarification, when you did the preliminary test you mentioned that the rise in kn was just the one bolt not sharing the load anymore. Then, you went full send on the whole system and the human test resulted in a 6kn peak force. What would the static force have been from a person on the line on one bolt? I'm guess I might have missed that number as a comparison to the 6kn peak force to prove shockloading is a myth. Thanks!

[@NJSlacker5]

Bobby says there's 2.18kn on the dyno before the test. (8 minutes in the video)

[@tomenright9]

@@NJSlacker5 not quite what I'm looking for but thanks! I want to know how much the meter would read if a human was just sitting on the slackline while using only one bolt. I feel like the measurement I just described when compared to the peak force would be a good indicator of whether or not shockloading is a myth.

[@tomenright9]

@HowNOTtoHIGHLINE

[@tehrater480]

I think the static force on one bolt would've been ~4kn, so the "shock load" saw a 50% increase in force up to ~6kn. I say this since the load was shared across two bolts with a sliding X (meaning pretty decent equalization) and there was a small angle between the slings. If the angle was wider, the force could've been less than 4Kn. Other Values: 1Kn tension before he was on the 100m line ~3kn on one leg when whipping (so ~6kn total force, maybe a little less.) Since the "shock load" force was ~6Kn, and a regular fall was also ~6Kn, I'm going to conclude that "shock loading" a dynamic system is fine! It's roughly the same as a regular fall on that same dynamic system. Shock loading is only really a problem in static systems, such as short mid/high/longlines using low-stretch webbing. But in that kind of scenario, taking a leash fall is already hard!

[@Jack-fk2js]

You lose the redundancy of the slings position if you use a sliding x. If there is a sharp edge near one of the bolts it is likely to cut all the slings. This can be controlled in other ways e.g. padding, but use your judgement on a case by case basis.

[@chrismuntean]

I don’t think that loses the redundancy. Are you saying to rig with no sliding x? Yes I agree if you do start rigging in a system that could have the master point move if a anchor point fails then you should account for that padding wise.

[@JasperJanssen]

Chris Muntean he’s saying that the individual sling doesn’t have redundancy compared to a BFK setup, in that if it is cut it is gone, as opposed to a BFK where if one strand is cut, the other strand is still there. The redundancy on the sling comes solely from there being three of them, as opposed to one. And if the first one is cut by something on your rock, and you don’t notice (because the other two will happily share the load), then the rock will happily start cutting the second one, etc. Or worse, it cuts all three simultaneously three quarters of the way, and then Bad Things Happen. So if there is abrasion potential, this is a bad thing. But then again with or without a knot abrasion is bad.

[@Papershields001]

Oh dude the timing of that whip…haha

[@nathanrooney2027]

Interesting video 👍

[@RogerBays]

With the sliding x I am thinking that there could be problems due to the fast moving nature of the sling after failure of a bolt anchor, causing: 1. The metal shackle to collide with something and cut/damage it. 2. A sharp stone to be scooped up off the ground and into the system and cut/damage something. Irrespective of whether shock loading is/isn't a problem in this scenario, why not use a separate sling for each bolt anchor, giving the bonus of sling redundancy? Also fast moving slings can burn though stuff!

[@professorsogol5824]

Where did you film this?

[@beaniebobh1]

Watch the first 30 seconds of the video.

[@ecoesportes]

Hi Guys! Congratulation for the nice job you guys do. Would like to enjoy and make a question. If one of this bolts brake, the sling will run, until get tensioned and hold the system. There are lots of slings together. If we forget about the forces, and think about the temperature of friction between one sling on another, would be posible to the sling be cuted trough the very high temperature and friction? Have you guys tested it? Thank you!

[@asldfjkalsdfjasdf]

Friction is only high enough for temperature to build if there is a load. With the presented setup there is no load just movement until everything snaps into place when an anchor fails.

[@RogerBays]

@@asldfjkalsdfjasdf I understand what you are saying. But would like to add that things sometimes go wrong and in unexpected ways. This might mean that movement and loading does not pan out as expected. The unexpected event/scenario is often what kills people. I would therefore suggest that the warning about temperature from the other person is valid. It would seem to be a good idea to avoid fast moving equipment from any safety plan, if possible. From an interaction design perspective, applied to safety, the idea would be to remove the need for movement, thus reducing the possibility/probability of a burn event to zero.

[@chrismuntean]

Roger Bays would a single sling be more reliable from an abrasion standpoint at least?

[@asldfjkalsdfjasdf]

@@chrismuntean If you attach them all in the exact same manner they will all move the same way. They will not rub more on each other than one would rub on itself. Except of course if your biner is to small for the application.

[@RogerBays]

@@chrismuntean I didn't understand your question, could you explain your thinking about abrasion in more detail?

[@victoroudit]

I would be more concerned about the speed at which the failling bolt is going. On your video the quicklink had a crazy speed ! But it holds so ^^

[@MephistoRolling]

if your components can handle 5+ times your shock load value. then it shouldn't matter, but just have to probably replace some components after it happens. seems better than no shock load but only a 2 times load buffer due to a knot.

[@williambloom350]

I like the videos where you break shit

[@teece900]

How many KN does taking a whip on the high line put on the bolts? How did that compare to the shock loading?

[@nathanielglavurdic4214]

i also feel like a standard quad anchor would do the same job and also still be a little more versatile, sick video though yew

[@Konsti8082]

mate what happened to the Audio

[@beaniebobh1]

River Noise.

[@wafflemeow126]

Cosumnes

[@Ma12cus1]

Achieve your deisred strength with no extension if possible. The sliding x with 3 bolts could be an issue of soft materials moving at different rates with a anchor point failure. Everything you did was reasonable, you had 132KN prior to shock load. Putting a knot in it would have left you plenty of strength. Great investigation! Skipping no extension seems very unnecessary to be honest :P PS- to anyone interested - dyneema loses significant strength as it ages compared to nylon. Take care all ✌

[@auklin7079]

listening on headphones, you need an exorcist

[@50StichesSteel]

Those slings are plenty strong to do that..Especially the Mammut magic slings with the extra abrasion resistance....Even though they let me down and didn't make it in Switzerland. Instead they chose China...That's one of the only things I don't like about Mammut. Slave labor is never a good way to make safety equipment. I like my workers to be somewhat happy with their jobs and making a good living lol

[@Mrich775]

I prefer to buy the safest equipment at the best value for my money spent myself.

[@Danger.Dan.4269]

Seems a little silly to purposely pop your redundant bolt. It's like jumping out of a perfectly good plane. BFK's are dope with 8mm rope. If your alpine, use one sling sliding x and tie off the tail.

[@Mike-oz4cv]

He still has redundancy from the 2 other bolts and presumably the backup rope is connected to different bolts as well.