Climbing Slings, Climbing Knots, and Climbing Anchors: Are Knots in Slings a Good Practice?

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I get tired of dogma, and climbing has a lot of dogma.

I think the reasons that climbing has a lot of dogma comes from an honest enough place. So, I’m not assuming bad actors. Imagine this: you were taught to climb 25 years ago. The Petzl Micro Traxion didn’t exist. The Petzl Grigri didn’t exist. Dyneema wasn’t an available fabric. You learned to use the gear you had. For example, if you ever had to ascend the rope, you didn’t have the Micro Traxion or Grigri to capture rope as you went up; so, you attached a piece of 6mm or 7mm cord to the rope with a prussik knot. You wouldn’t want to use dyneema, even if it existed, because dyneema melts easily and you don’t want to do friction knots with it. So, you learn the indespensible nature of a good piece of cord.

Now, 25 years later, a young climber uses a Micro Traxion or a Grigri as part of her rope ascending setup. They may even have a Petzl Tibloc to attach the foot loop. So, no need for cord. This equipment makes the whole process of setting up to ascend and then ascending much faster. And that matters if you are ascending the rope for - say - a rescue of an injured climber above you. But that old cord that our young climber no longer carries means something else might be needed to build anchors, as the cord was good for that, too. There is a strong and light material now available: dyneema.

“How can you not carry cord!” says the old salty climber. “It’s so useful! That dyneema stuff will kill you!”

Well, the old salty climber is kind of right, dyneema can kill you if you don’t know how to use it. It does melt easily, and it is so static that if you fall onto it from above the anchor, it can snap. But the young climber knows this. She isn’t going to anchor in from above the anchor. She isn’t going to make a friction knot. But she is stoked to have a super light, super strong piece of material to belay from above when she sends her lead on the multi-pitch climb (for example).

“How can you still carry that cord! It’s only a third as strong as my sling. I wouldn’t trust that!”

But while the salty old climber doesn’t know how strong the new dyneema stuff his, he has always known that his cord wasn’t strong enough to make an anchor out of without doubling it over or tripling it over into a two- or three-piece cordelette. That makes it as strong (or stronger) than the climbing rope.

You see where I’m going.

We know what we’ve been exposed to. And in a game with as high of consequences as climbing, it easy to get dogmatic about that thing that has kept you alive thousands of times because you know how to use it and it has (to this point) always worked.

And in a game like climbing, as you’ve heard me say in this video and others, there are no perfect solutions. There are always trade offs. So, it’s fairly easy to point out the weaker points of a technique, piece of equipment, or system configuration. What’s harder to know is why that other climber might place less emphasis on those weaknesses and more emphasis on whatever the count-balancing strengths might be. Maybe the high altitude alpine climber really does want the lightest possible stuff. Maybe the multi-pitch trad climber who likes the off-the-beaten-path routes sees a lot more rough rock and rock fall and thus needs more robust (and thus heavier) materials.

The dogma, I think, comes from honestly wanting to help people avoid mistakes, coupled with a lot of confirmation bias (‘this has always worked for me’) and a difficulty in getting and understanding the deep context of another climber’s choices (if for no other reason than that conversation takes a lot of time).

So, I made a video about a place where there is some (not for everyone) deep dogma. Dyneema slings get weakened by knots even more than other materials. But we still take up dyneema slings and we still tie knots in them for anchors. What could the reasons possibly be? Well, like the video discusses by using three different anchor configurations as case studies, sometimes you are trying to emphasize one side of the safety equation that is more pressing than other aspects of safety in a particular moment.

I think that’s why I feel it’s so important to keep learning about this stuff. New challenges come about as climbing evolves. Those new challenges may demand new approaches and techniques. Not long after, new gear comes along to facilitate those new techniques in a safer way. But, being tailored for that purpose, maybe the new gear isn’t as good as some other application. We need to know that. Our lives depend on it.

The dyneema slings I use in the video are the Mammut Dyneema Contact Sling 8mm (wide) which can be found in various lengths, here.