The Theory of Slings
My buddy followed me up a pitch and said he couldn’t believe that I’d clipped old tat on a fixed piece of pro. Can a bundle of tat collectively be strong enough to hold a fall or rappel? We were climbing in the Gunks, and there are often multiple pieces of tat (old slings, faded nylon cordage, fuzzy climbing rope) tied around natural features. I had clipped an extended draw to the wad and moved on, having faith that at least one of the slings would hold. The only info I have found on old-sling strength is an article by Kolin Powick on the Black Diamond website. He tested crusty fixed draws from Rifle. Some had a markedly reduced strength, but 80 percent of them still retained most of their strength
I could predict with greater accuracy whether a stray dog will bite you than guess if a fixed sling or a bird’s nest of them is reliable.
Ten years ago I climbed an ice pitch to a chockstone slung with a newish runner. Figuring I was at the belay, I clipped a biner to the sling, tied off and was about to sit back and relax 100 feet off the deck when, on a whim, I tugged on the runner. It broke in my hand. A mouse had gnawed through the webbing on the back side where I couldn’t inspect.
Of course in your situation you believe in safety in numbers, clip the wad and press on. What else would you do? I reflect on the Multiverse Theory, which says that there are parallel, infinite alternate universes where everything and anything happens simultaneously. In one universe the slings hold, in another they fail. This comforts me and explains coincidence.
I might also add my own sling, threading or wrapping the natural feature or piece of fixed gear. This is situational, and often too inconvenient (in this universe, anyway), requiring a hang and cutting away the tat, a job for the “Crusty Crag Keepers,” those bored oddballs who replace perfectly good rusty bolts, chain up stations and swap bleached-white slings with new ones.
As Powick noted in his excellent treatise, some fixed quickdraws and slings are strong, yet others could break under common climbing loads. Most makers of webbing and rope test their products for UV degradation and know with accuracy how much strength their nylon and webbing loses over time when exposed to sunlight, but that information is useless for climbers. On the crags and in the mountains, slings and cords are subject to more abuses than the Marquis de Sade could fathom, and UV, the intensity of which varies by altitude and latitude, is just one of them. As I discovered, there are hungry mice. There’s also rockfall, wind rasping the slings back and forth across the rock, and abrasion from nylon-on-nylon contact when climbers pull their rappel ropes directly through the slingage. Unless Powick can accompany you and test tat on the fly, you have no reason-backed idea of whether it is solid or shite.
To sum up, safety is variable. Err on the side of caution. Replace tat in mission-critical situations. O.K., I’m bored and off to replace some crusty slings. Next!
This Gear Guy question appeared in Rock and Ice issue 251 (July 2018).
Got a question? Email: firstname.lastname@example.org
Feature image: John Hegyes
Rap Ring Strength
I have seen many rap rings while climbing and doubted their strength and safety. The SMC rings have no mark with an EU number, strength or anything. They may not even be SMC, who knows? … Continue reading “Rap Ring Strength”
Why Do People Use Oval Biners?
Why do people leave oval carabiners at rappel stations? Are they super bomber for that use? —Cracklord via rockandice.com Oval biners are the dumpy weaklings in the herd, left behind to die because no … Continue reading “Why Do People Use Oval Biners?”