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For me the most interesting point is the effect of knots and slippage into the system. Everyone mentions that knots weaken slings, but these tests emphasize that slippage of the knot adds a dynamic element to the system that lowers the peak force. Not mentioned in the video is the effects of these forces on the human body... I am not sure what happens to a climber who absorbs >12kN of force from a fall. I imagine serious injury....
So your right that he mentioned the knots add a dynamic element, but they also reduce the total strength by half, so the knotted ones ended up breaking while the unknotted one did not break.
The biggest weakening in these examples is when they clove hitced to the anchor points with a sling. Then they got only one strand of the sling loaded and that will break it a lot easier.
Good thing I'm not a solid chunk of metal using a static rope. A human wearing a harness, falling on a dynamic rope helps cushion shock, our bodies are bags of liquid & a harness & rope has a lot of give, HowNOTtoHIGHLINE has a number of videos on why shock loading is generally a myth & with dynamic rope + a harness + human... a human will never go over 5kn of force on even the hardest fall. Interesting test though.
You describe a very different situation that is not tested here. Whats tested here is a situation at a belay anchor, where you often have no dynamic rope in the system. Also in these situations factor 2 falls on static lanyards/slings are possible. And in these situations shockloading is not a myth, bc there is no dynamic rope in the system that absorbes the shock.
You could not be more mistaken; lost two friends around twenty years ago, when their anchors were ripped, probably from a short but FF2 past the belayer; they went about 800 feet to the base of Middle Cathedral in Yosemite. Impact forces of lead ropes are designed to stretch below the threshold of serious injury to a climber. Petzl's site shows real world measurements in belayed fall scenarios, where a belayer feels 2kN, the leader feels 4kN, and the top piece feels 6kN impact force. A long factor 2 fall requires many feet of stretch in a dynamic rope to spread the force over time, and the notion that a flexing bag of fluid can absorb such energy over a foot or two is absurd. The far more dangerous, yet intuitively underappreciated scenario is dropping a few feet, but onto static sling or chainlink anchors, where a climber commonly has little or no dynamic material in the connection. Clipping in to a one foot chain with 6" of lead rope, stepping above to rig something, and dropping down makes a fall of three feet, onto just 1 foot of dynamic material, and effective FF of 3. Replace the rope with a static sling, and you have an incalculable fall factor, with only the harness and body to absorb the impact. And there is not "a lot of give" in that situation.
And yet with all the knowledge and instructional material out there. Here we are in 2021 and THE widely accepted and prefered anchor buding material for the common outdoor climber is.......... 240cm Dynema sling.
Dyneema slings are perfectly safe to use as an anchor IF you have a dynamic rope in the system. It is almost common knowledge now that you cannot use a sling by itself as it's static and not good at taking shockloaded impacts.
@@sanchoviesfan6971 Go read the intructions that come with ANY Dyneema sling "DYNEEMA SHOULD NOT BE KNOTTED". Same consensus from every reputable climbing equipment manufacturer. Case and point!
@@Max-ik9qb The warning exists to tell you not to tie a dyneema sling back together if it was snapped or cut as it risks slipping. Using overhands or a figure 8 to make a master point in a non compromised dyneema is not an issue. A knotted dyneema sling will still be stronger than the 3 nut traditional anchors they are attached to.
@@Max-ik9qb I almost exclusively top rope from 11mm nylon slings or 8mm dyneema slings tied exactly like I said above. The exception is using cordalette or static rope when I need to extend my anchor beyond a lip. What material do you build your anchors from?
Dyneema failed and Nylon didn't -- I would rather have Nylon Dyneema's impact load was significantly more than Nylon -- I would rather have Nylon Dyneema is less bulky than Nylon-- I would rather have Dyneema in this case Wait a second, impact loads are much less in Nylon, why not decrease the bulk of Nylon? Nylon is less expensive too, so it can be replaced more often if we are worried about abrasion and UV exposure.
And as a mountaineer I always use dyneema over nylon (that stuff stays in my sport climbing bag). Nylon will saturate and freeze at which point it loses significant strength, whereas dyneema sticks it out like a champ.
I've used the primary rope as much as feasible, with clove hitches or my all-time favorite, Butterfly knots, at anchors for over fifty years, and I find the modern sling-heavy systems to be "guide friendly," quicker to set up especially at fixed anchors, easier to swap the clients and then continue, the guide always leading. But, the extra complications, significantly weaker shock accommodation, and such I find troubling. The beauty of clove and Butterflys are they are rapidly adjustable while still tied in, and the BK is as strong across the loop as it is into the loop; it allows a lot of flexibility in opposing or combining directional elements, equalizing without extra slack added in a partial failure, and overall a far cleaner less cluttered look. On trad routes, as long as you have adequate rope per pitch, sling systems are far less versatile than good old lead rope tie-ins.
thanks for your comment, i realise it was a while ago but i have often wondered about using alpine butterflys in belay as it seems very elegant, do you have any suggestions on how to do this or reading material?
It makes me wonder if a smaller, lighter nylon sling is better to climb with than a Dyneema sling even if the static strength is stronger. We climbers don't put large static forces on slings, we put large dynamic forces. Dynamic force matters!
For instance, static testing has shown that knots in rope reduce strength ~50%, yet in these test it looks like the failure was not always right at the knot. If the failure happens at the knot and the not comes undone, there is not redundancy. YIKES!
I have a great respect for DMM products but this experiment is only valid for 80kg iron block, which doesn’t behave like the human body at all. Human body absorbs energy much better and it is more like a water bag instead. For real scientific results you should use a volunteer or a ballistic gel dummy. Still recognize the effort.
DMM make great gear (and I've got loads of their stuff) however, they are hopeless at answering customer inquiries, especially ones that concern cracks in pulley axels.
It’s not what it looks like. The harness worked GREAT.~~>lovy.biz/kk95?ほD If not, he’d have been in trouble. His assender got stuck out of reach. He hung for close to an hour before he decided to call for help (don’t climb alone ppl) but the harness kept him in place til I could rescue the man.
Anyone else notice how much force DMM's test rack absorbs? When one point fails, the rack is immediately impacted and swings quite a bit, absorbing a lot of the shock that the other components would've taken instead...Seems like in a real-world setting there would be more failures in their test setups?
@@KillroyX99 The rig is attached to a force meter so that they can obtain all the data that he was discussing. If you attached the anchor points to a static point like a climbing wall you wouldn't be able to measure the force introduced to the system.
@@eagle191, thanks for your comment. The test rig could be riddgidly attached and the force meter could be added at any point that they want to measure. This would be just fine tuning the "Design Of Experiment". As mentioned before, the change that would add the most realism is a falling dummy that acts like a falling climber (rigid mass vs compliant body)
I hate this video, so many climbers see it and think "OMG, dyneema is death." A steel weight is a poor model for the human body, especially at the lower end of the energy scale with small falls on static gear: skin sags and stretches, limbs/muscles extend, blood sloshes to the extremeties, etc; which all absorb quite a bit of energy and reduce peak loads. I understand that rigid steel weights are a cheap/practical way to get repeatable results, and the results extrapolate well to long falls on a rope (where the energy absorption of the body becomes a smaller component), but it gives unrealistic data for climbing anchor scenarios.
The test I would really like to see in addition to the others in this fine video are the forced involved when there is a short amount of rope (ie 1 foot) tied into the anchoring slings then drop tested. This would produce ie a 5 foot fall with one foot of rope out. I think we might be very surprised at the forces generated?
A kilonewton is a dynamic force. Kilogram is static. They would easily hold 15 or 20 of you. However, If you took a fall above the anchor point and the sling had to absorb all the energy built up during acceleration, they might not make it.
Nice work, congratulations. Could I have a kind of report including all these important information about the tests for a better understanding? Thanks.
Very interesting video, thank you for posting. I think the real world takeaways for this are: 1) Avoid using dyneema runners in an anchor system; use nylon or the rope instead. 2) Avoid using the sliding X unless you use limiter knots to minimize extension. 3) Don't be a f**king idiot and climb above your anchor when only attached to it with a dyneema runner! 4) Shout out to Black Diamond, DMM, Metolius, Petzl: Why is it that you tech wizards cannot manufacture a runner with more stretchy, dynamic qualities, when doing so appears to clearly minimize impact forces on rock protection? I'm talking about something like a really strong bungee cord is the core of a nylon runner. Any company that can figure this out could revolutionize climbing.
@@eagle191 It's just about the anchors and also only the persons directly connected to the anchor. With the pieces along the route (or your seconding climber) there's always the rope in the system, softening a fall.
I am curious, I often use a 120mm sling with a clove hitch around a master beener (very similar to the overhand knot example). I was surprised to see your clove hitch example using only one strand of sling down to the master point.
Worst Snake Oil video over ... Dyneema® and other static protection gear is not meant to be fallen on directly ... all of these anchors would held up just fine when you take an actual fall (attached to a dynamic rope) The extension in the rope is way more than any extension you might get from the anchor setup itself making that extension pretty meaningless. Let me guess DMM makes ropes and does not make slings ?? These video reminds me of the videos of ppl breaking tungsten rings with a hammer trying to prove to customers that they would be better of buying more expensive gold engagement rings. Failing to mention that what matters is scratch resistance and ppl are unlikely to ever actually hit their ring with a hammer.
Great video, thanks a lot!! A climbing instructor in France, after seeing me use a sling to tie into belays, told me to buy a piece of climbing rope and use that because of the possibility of a factor 2 fall when faffing about at a belay. I always wondered how correct he was and now after seeing your video am really happy that I have been using this ever since. thanks!!!
