14 tests on triangle bolting patterns for highline anchors - do they equalize?

We did 14 tests on our new favorite 3 bolt pattern - the equilateral triangle. We did sliding Xs and BFKs and short anchors and long anchors and static ropes and dynamic ropes. Our results were shocking, so check it out so you know what is going on inside your anchor when you go highlining.
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[@HowNOT2]

Check out our new store! hownot2.store/

[@ocAToccd]

Hello, thanks for the test! But... Sorry for digging this old video... Sorry for my lack of climbing technical English... Sorry to disappoint some of you guys... I am an engineer too... I will try not to go wrong... Two things mainly play here : stretching and friction... Imagine an absolute non stretchable rope. If you preequalize the load it should stay equalized with or without fiction (everything will stay proportional). Then imagine a rope (stretchy or not) in a frictionless world. With your "sliding X", the tension will be the same in the whole rope (principle of pulleys), whatever the pattern or the length of each strand... Now take your stretchy dynamic rope and a BFK. Even if you preequalize perfectly, if you don't have strands that are of the same length, when you put your line into tention, the strands will stretch at different rates because the common node moves X cm/in for all the strands but the tension on each strand is proportional to the "relative" streching (X/length). As for the sliding X in real life, the friction does not let the tension equalize... I would say mainly at the common node where the three strands are against each other... You should try pulling (to the side or the sky) on one strand to see if you can make it "slip" and change the equalization... So... In theory (!?!) you should put your anchors on a arc of circle with its center at the common node. The bigger the radius, the better because any "misequalization" at the beginning will be smoothed by the streching. And because the forces in each strand will sum more efficiently if the strands are parallel... But your BFK will never be perfectly equalized... Because you are human... Sorry... Even if it could be super good enough ;) The problem is that you cannot check without keeping the dynos all the time... As for the sliding X, independent pulleys at each anchor AND at the common node should do the trick, whatever pattern you use... But I don't know if pulleys are allowed... And you would need 6 of them... I hope it will help at least one guy (or girl)... Stay safe !

[@nirvanero85]

i don´t even know how a mountain looks, i just really like the knots and builds. Amazing channel

[@owenroll24]

You should break test a harness and belay loops I know you've probably got a billion other tests to do but I've never seen a specific kn rating on a harness and it's got me curious

[@HowNOT2]

I think that would be an interesting test for sure. How do you think i should do that? Just pull the belay loop? I could have those made and break those. Maybe connect harness to one side and belay loop on other? But that shouldn't have such a tight bend since our hips make the entire thing round. Shoot me some ideas!

[@owenroll24]

@@HowNOT2 I'd do the belay loop alone, the waist belt being pulled by the main contact point and a leg loop since the harness would basically be destroyed at that point Truthfully I'm most curious about what the waist loop would break at being pulled by the contact point since that's the most life saving part

[@HowNOT2]

I can get normal harnesses for like 30 bucks... i think i can do this! :)

[@HowNOT2]

Don't bid on anything on ebay for a few days. I pretty much bid on all of the harnesses! :)

[@mirkocoser5049]

harnesses are already tested by the companies who produce them and they must support at least 22kn (if i'm not mistaken), so why testing them?

[@mrlinsky]

@HowNOTtoHIGHLINE what is the orange shackle with the quick release pin you are using?

[@billhickswasgreat3421]

Wait, is it even mathematically possible to equalize the three. Isn't it normal for the inline bolt to receive the most load? It is probably a function of the geometry what is left for the other two bolts.

[@stephenevans2518]

It is mathematically possible, depending on what you count as equalised. In the sliding example, the tension in the rope is able to equalise itself and so force on the bolts will be equal. In the version with a knot, it will all depend on how equal the knot was tied, but assuming they are all pulling together the two side bolts would have a higher force, as the force in the direction of pull would be even, but because of the angle on the side bolts there would be extra force as there is a sideways component as well as the one in the direction of pull

[@philbox4566]

That was brilliant. Plenty of crossover information here for other areas of rope work too. With that equilateral triangle on a wall, yes, it does change everything. Would need to spread the arms out to between 60 and 90 degrees which will then cope quite well with a shifting load. as long as the zone of influence does not stray outside the constraints of the inside of the triangle. Strong work mate.

[@winchesterdown]

The friction of the master point on the sliding X is likely to have an affect Ryan. I know you suggested it doesn't however the best example of when the friction made a big difference was in the park video with spike anchors you did. One test showed the two middle anchors were not equal which makes no sense. The other example of why the friction also affected things was how equal the v configuration equalised. There is no rope/sling overlap on those. In this video, there is an interaction as you tighten up the ratchet, the sliding X master point overlaps and as you use static rope the forces can build up in one line quickly. The force of the rope coming from a lightly loaded anchor (the outer ones) is enough to induce a high load on a rope it overlaps. The static rope had a much lower load in the central bolt (when way back) due to the increased stretch on the longer line. As you know, a longer dynamic file, will stretch further. It could be possible to add tension to individual bolts to allow you to equalise anchors in any configuration. I'm thinking something like using a tensioning spindle like on a fence or building cross bracing. They are bomber and easy to adjust.

[@winchesterdown]

Like this turnbuckle images.app.goo.gl/P9vsxeZaYxDLfmeJ8

[@johnliungman1333]

Trying to wrap my head around this. Is it true to say that IF the carabiners were zero friction, the load would always equalize fully, regardless of geometry, material, etc? But since even in a sliding-X configuration, carabiners may give 40-60% friction, we get all these other phenomena involving angles, stretchiness, etc. I also believe your different cords may give different coefficients of friction. Even the load itself could affect the coefficient of friction. So any assumption about zero friction sort of collapses the whole model.

[@lyudmilivanov270]

Call me a troll or whatever but kind of bugs me that the all of the figure of 8s knots are not "properly" dressed. Good info and effort no question there. Thank you!

[@ShurikB93]

That pattern actually looks great, I think you will get better results if you'd measure the equalization at the same force on the master point every time. Even better to have 3 measurements, low tension , normal tension , high tension (for actual highlines) But that is just my engineering OCD brain bothering me. Edit : Can't type for shit

[@HowNOT2]

Its hard with just a rachet. I would pull hard each time to what felt the same but id get very different results depending on stretch of anchor material. It also settled sooooo quickly that i wouldnt be able to get and keep a number if i wanted. Main idea was just to compare master with each point. Slack science is a little bit slack about its science :)

[@shcottam]

Idk if this is a cluckbait title. More like a bomber title

[@markh16]

The Center bolt will always have twice the force as one of the side bolts regardless of how far back you put the center bolt. You have basically set up a 2 to 1 pulley system on the middle bolt. If you added pulleys (thus removing the friction) onto all the dynometers, you would see that the center bolt always carries half of the overall load and the two side dynos share the other half of the load. It's a pulley system. Each side pulley is 1:1. If you want to equalize the loads, simply use three different ropes - one to each dyno instead of one continuous rope (or alternatively tie and overhand not at the bottom of the ropes).

[@quoikoi]

Please test the grand wall cams a new brand DO IT

[@sebabalo]

Nice video. Well done

[@vertikalohigh9583]

HAAAAWWWW, "skatchy" Andy Lewis owns two dynomometers???? He should be renamed "scientific" Andy :D

[@rikuswessels2918]

Try a isosceles trapeziod instead to equalize, 4 bolts but the anchor looks like a single V.

[@17hmr243]

So if ur 100 m out and fall off how do u not swing back to the wall at speed?

[@jvalentine8376]

To share the load better the two side anchors need to be closer together so they are sharing more of the inline force . The wider they are apart from the centre line of force the less load they take . Using dynamic rope means that the longest leg of rope has the most stretch and as a result shares the load more evenly . To work out what bolt configuration works best you should use chains not ropes to remove the stretch and knot loading variable . Connect a bar across the two outer bolts and slide the connections in and out to vary the angle to the centre line to see the force variations . There is only going to be one best configuration for a pull in one single direction .

[@johnhutsenpillerjr1785]

Why don't you put those meters in use on a real setup !! Then use a weighted pulley assembly pulled out to the middle of the line to see how much tension is really on the line when it's in use like you were using it for real ???

[@TheBradosaurus]

Great video, Ryan. About the sewn loop/soft shackle connection, there was an incident where the fabric on fabric connection as you show it cut straight through. This was at Natural Games in France where a trickline tail was tied off to a 6mm rope (possibly Amsteel, but possibly regular cord). The trickline weblock broke and the tie-off cut straight through the webbing, causing the weblock and webbing to hit the trickliner. As far as I recall, his face is permanently scarred and has only 80% vision in the eye that was hit. What do you think about making a video to test your claim? Since there was an incident where the non-sliding fabric/fabric connection failed, it would be interesting to learn what are the factors that influence that kind of failure. If you do, I it should probably be done on a stretchy webbing that's longer than 20 meters to reflect a real-world scenario. Thanks for putting all the effort into these videos. They're great at getting people to talk about the ideas.

[@HowNOT2]

Hi Bradley. I'd like to know more about that failure. I would be nice to demo that in a video of situations that it can fail. Rope on rope in some situations is bad but we also have it all over the place where it is acceptable-ish. Spacenets are nothing but rope on rope. Tying our ropes to our harnesses is rope on rope. Our leashes rub on our webbing when it has to switch sides when we fall the wrong way on our highlines. Our backups are constantly flipped over our highlines.... AND I have broken all my sewn loops tests with soft shackles at the loop (stitching or webbing by stitching always breaks) because it is less hardware to go flying and have used soft shackles on loops on 100% of all my highlines for over 4 years with no sign of abrasion other than wear and tear. I truly don't even know how to make it fail... maybe a drop test? Shoot me some specific ideas and I'll make it happen!

[@TheBradosaurus]

@@HowNOT2 Here's the report on Slackchat from June 2015: facebook.com/groups/slackchat/permalink/888549237885621/ This isn't to say there's no place for fabric/fabric, but I'm not sure we fully understand the failure modes, especially in dynamic events.

[@HowNOT2]

It looks like the forces they were seeing were literally 5x what we can even achieve on any highline situation (that isn't trickline related). 6mm accessory cord isn't very strong and the thinner the material the more likely it will cut through the opposing material. 6mm dyneema highline backups are no longer a thing because it cut a bit of a main line in a wind storm. Round surface area on flat webbing while oscillating back and forth. If you look at my instagram post ( instagram.com/p/Brp52gxF7We/? ) with the 9mm soft shackle breaking at 179kn in slow motion, you can see all the "catchers" that keep the pulleys from flying breaking as if they aren't even there. I imagine what happened in that test is similar to what happened to this trickliner. However a soft shackle on a sewn loop is large radius, non-oscillating, generally padded situation and basically can't cut through the loop regardless of the pressure one puts on it.

[@TheBradosaurus]

The difficulty is to make a general statement which says non-moving fabric/fabric connections will not cut through because there's no friction, even though there are incidents where they did indeed cut through. I don't disagree with your reasoning, but there are plenty of people out there who don't understand the nuance for *when* fabric on fabric is okay. I think a video that looks into the failure modes of fabric/fabric connections would be very interesting and spark a healthy discussion.

[@HowNOT2]

@@TheBradosaurus i think an epsiode diving into when and where it is an absolute problem, where it can be safeish and where it is bomber would be helpful for sure.

[@jmy106]

Fair play, this was effort. Really useful video thanks

[@thatfamousguy]

dude. i'm an engineer. your maths it out. its trigonometry, really easy to work out. those two side bolts will never equalize with the centre one, its trig

[@HowNOT2]

Nothing is basic math when you have things moving and stretching. If it was so simple why did a painting contractor figure out an equilateral triangle is best for highline rigs? haha

[@johnliungman1333]

With zero friction, yes they would. But zero friction does not exist...

[@tiberiu_nicolae]

Don't expect slacklining people to understand math and engineering lol

[@cluelessbob7372]

4 months

[@matthewluttrell9413]

Angle matters, distance doesn't, if friction isn't a factor. If each anchor was tied with it's own rope, and you could get them all equally tight before tensioning, the longest rope will have the lowest spring coefficient and see the least force (at more extreme angles that could change a bit). A more elastic rope will show this better. Now if we used one rope like you did and then used pulleys on all the connections, we'd see that the center anchor will always have the highest force. A stiffer rope will show this better. Jostling the ropes while tensioning will approach the example with the pulleys, where it's purely the angles that matter.

[@tiberiu_nicolae]

Pretty scary how youtubers improvise themselves as experts