Hitching a sling direct to a stopper wire - acceptable?
Let's make one thing clear right up front. Doing this is definitely not standard practice, it's best to use a carabiner between the sling and the stopper wire. However, there are a few unusual situations when it might be good to have some other option, such as:
You’re leading a trad climb. You place a stopper, clip a sling to it . . . and notice that the carabiner that’s clipped to the stopper is going to be dangerously loaded over an edge if you fall onto it. No bueno.
You’re on a long lead, you’ve run out of spare carabiners, and you only have stoppers and a few runners to protect the next few moves.
You need to make some retreat anchors for many rappels, and don't want to leave any carabiners behind on the stoppers you’re placing for anchors.
Can you hitch a runner directly to a stopper, rappel or even take a whipper onto it, and live to tell the tale? Let’s find out!
Two ways to attach a sling directly to a stopper wire: (top) girth hitch (aka lark’s foot); (bottom) basket hitch.
Traditional conservative climbing pedagogy would probably say:
“Yer Gonna Die! (YGD)”
But is it really that bad? Climbers have been wondering about this for a long time, and the clever engineers at DMM in Wales actually did some pull tests on this. Any video that breaks both gear AND dogma is one I’m definitely interested in! As the clickbait web ads say, the results might surprise you.
from the DMM website and video:
“To answer this question we took a Wallnut 1 and 11 and tested them with a sling attached using a lark's foot and a basket hitch in combination with 8 mm Dyneema (Dynatec), 11 mm Dyneema and 16 mm Nylon slings. We also tested lark's footing a Wallnut 1 together with another Walnut 1.
The results (see table below) were conclusive in showing that basket hitching is the best way of extending a wire over an edge to protect your carabiner.
Using a basket hitch with the Wallnut 11 always failed above the nut's minimum strength rating of 12 kN. The same was true using a basket hitch with a Wallnut 1 having a minimum strength rating of 7 kN.”
Results from DMM pull testing
Short answer, yes, very acceptable! =^)
Does the sling break? Yes. But, with a basket hitch, it breaks ABOVE the rating for the stopper it's attached to!
To summarize:
8mm Dyneema sling > girth hitch > tiny #1 stopper > breaks around 7 kN
8mm Dyneema sling > girth hitch > medium to large stopper = breaks around 8 kN
8mm Dyneema sling > basket hitch > medium to large stopper = breaks around 12 kN
Being that 9 kN is about the largest force you're ever going to have an a climbing fall even with the crazy factor 2 fall directly on the anchor, those results are highly encouraging, at least in my mind.
(See this link for a chart on climbing gear strength ratings)
So, the short answer is, no problem, you can hitch a sling straight through the wire of a stopper. Doing this with a basket hitch is clearly stronger, but you can even use a girth hitch and still probably get away with it.
Note 1: I don't know this for sure, but I’m guessing that DMM tested this with a slow pull to breakage, and not hitting it with a sudden force in a drop tower. I would be quite curious to see a comparison between the slow pull and a dynamic fall.
Note 2: If you’re near the end of a long pitch running out of carabiners, it might be best to do this technique when building your anchor, not placing gear on lead. This is because the force the anchor could take when belaying your second is probably less than what you could potentially put on it from a lead fall. (Of course, when the second arrives at your belay with all of the cleaned gear, you can add proper slings onto those stoppers.)
Should this be your go-to technique to clip a stopper? No, probably not. But, when you run out of carabiners or have something loaded over the edge, know that you can do this (fairly) safely. Plus, get ready to see an incredulous look on your second’s face when they arrive at the anchor and say, “DAMN, what’s up with that stopper and sling!?”
