Oh, to release a book to the world, suddenly every fevered kook can sequester himself in an attic and critique your every word. Especially in the time of COVID, any obsessed mountain guide can lock herself away and pick your techniques, photographs, and text descriptions apart with a fine-toothed comb! The pressure! The microscopic attention!
I’m being a diva, OK, I’ll shut up and get to the point. Thanks to my buddy aikibujin (MP handle), Marc and I have learned about a very unlikely, but potential failure mode in one of our systems in The Mountain Guide Manual. To experience this in the field, it would have to be a series of improbable “ifs,” but you’ve probably read enough accident reports to realize … that’s exactly how a climbing disaster can occur: a series of unlikely glitches and errors, compounding into carnage.
And who likes carnage, except in John Wick films and Supreme Court confirmation hearings?
We describe the technique in question on page 110:
Another strength of the new system is that the leader, by going first as suggested, never unties from the end of the rope. This increases security in a few ways. First, because the second rappeller ’s device is pre-rigged on the rope, the rope is locked into the rappel anchor. It can’t slide one direction of another, which means only one stopper knot is needed at the ends of the ropes to the prevent first rappeller from going off the end.”
It’s this idea that a pre-rigged device definitively fixes both strands of the rope at the anchor that requires more thought. With most ropes and devices, this seems to work – but aikibujin was monkeying with this technique and decided to test out the scenario in which the first rappeller, still tied into his end of the rope (because he was the leader of the last pitch), descends both strands of the rope, but then accidentally rappels off the unknotted strand. At this point his full weight comes onto the strand to which he’s tied.
This is page 118 from The Mountain Guide Manual, in the “Transitions” chapter, in the section describing “Three People, Two Ropes, Using Caterpillar Technique (Speed Technique*).” I added the text boxes to reiterate the context — the leader (gray t-shirt, black tights, right in the photo) arrives and belays the first follower (green shirt) on the red rope. When the first follower arrives, he secures himself by cloving in on his trail (orange) rope.
While the leader belays the second follower (left in photo, black top), the first follower puts an extension on his harness and puts himself on rappel on the backside of the leader’s clove on the red rope. He puts a third-hand backup on the rope below his rappel device, double-checks himself, asks the leader to do the same, and then he can untie on the orange rope. The free end is hanging (with its figure-8 still in the rope) against the cliff.
Meanwhile, the leader has put herself on belay on both strands of the ropes—-on the backside of her own clove on the red rope (above the first follower) and on the backside of the clove that the first follower built on the orange rope. This usually fixes both strands of the ropes, so both rappellers can rappel on a fixed strand, not simul-rap against each other. It’s this element of the system that aikibujin home-tested and found that certain device/rope combinations don’t necessarily fix the strands. Should one rappeller go off her/his end of the rope, it could result the rope slipping/feeding through the anchor, ending in an even bigger catastrophe.
Photo credit: Philbrick Photography
With most combinations of ropes and devices, the pre-rigged device above fixes both strands securely. I went out to the cliff and tested several devices on the same rope to check this. It’d be pointless to describe every rope/device combination, but it suffices to say a couple combinations experience some slippage, while one slipped completely.
Now, before your palms get sweaty and your put all your gear on Craigslist, rest assured, many unlikely problems would need to align to have this occur in the field. First, you’d need to slide off the end of the rope—unlikely but certainly not impossible.
Second, the unknotted strand would need to be shorter than the strand to which the first rappeller is tied---again, unlikely because the rappeller ’s knot will take up close to a meter of rope, thereby meaning he would come tight to his knot before he would go off the end of the rope. Probable, but not guaranteed.
Third, the pre-rigged rappellers do not have third-hand back-ups installed. Pretty likely, I’d say, as having a third-hand on the rope is often a hassle when someone is rappelling on the rope. If one of the pre-rigged rappellers has a brake hand on the rope, it would also prevent slippage.
Finally, the rappeller who goes off the end of the rope, the joining knot for ropes would need to be on the same rope to which the rappeller is tied, otherwise it would most likely jam at the anchor and prevent slippage.
Lastly, in the event the first rappeller did go off the end, and the rope/device combo on the pre-rigged rappeller(s) didn’t fix the ropes at the anchor, and the pre-rigged rappeller(s) didn’t have hands on the brake strands, and no third-hands on the brake strands, they would have some time to arrest the sliding brake strand at their device. Grabbing the brake strands might work, might not – let’s not find out!
I reproduced this failure on an 8.3mm half rope. I rappelled to almost the base of the cliff, then intentionally unclipped from one strand of the rappel approximately 1m off the ground. Above me I had pre-rigged a weighted backpack on a BD ATC Guide. As soon as I weighted the single strand, rope fed easily through the device and the anchor above. I rebuilt the system with an ATC Alpine Guide device (same rope) and it locked securely. I couldn’t get any slippage, despite bouncing and yarding on the rope. Same result with an Edelrid GigaJul device (rigged in non-assisted-braking mode).
Point is, with an unlucky rope/device combo, and a few unluckily aligned details, this could end in a system failure.
Fixes
So let’s talk fixes! Luckily they are many and they are easy.
First off—simply knot the end of the free rappel strand. The only time I don’t knot end the ends of the rope is when I’m worried about the rope becoming stuck due to the stopper knot. I came upon two dudes rapping Prince of Darkness one time, with their rope snarled about 25m off to the side. They’d begun their rappel and then an enormous gust of wind came up, blowing one of their free ends almost even with the second rappeller (elevation wise). He was sitting there, looking at this rope, while his buddy was at the anchor below. Much rope trickery and sketchiness ensued! (Everybody was OK!)
Second, make sure the second rappeller has control of the brake strands. Keep a hand on them while the first rappeller descends.
Third, put a blocker knot of some sort below the pre-rigged rappeller(s). This could be a clove-hitch on a big locker, as it’s easiest to break down after the first rappeller has weighted it.
Fourth, have the pre-rigged rappellers install third-hand back-ups on the brake strands. Least appealing, as then they have to be close to the weighted strands, which is usually uncomfortable. (One thought on this: if you have two devices pre-rigged on the rope at the anchor, the chances of slippage are even more remote.)
Considerations
As soon as we add complexity at the anchor above, we need to be darn sure we are not adding the potential for a catastrophic mistake. Guides love pre-rigging clients above with no tethers clipped to the anchor because then all the client needs to do is start rappelling—no untying, no unclipping, no chance for a confused/stressed person to unclip the wrong carabiners/etc.
Don’t discount, too, how tightly set a knot can be after your chiseled magnificence weights it for a full rappel. A tired or weak client will not be able to undo a stopper knot and guess who’s ascending the rope to go sort it out (after much hollering and frustration)? You and me, bruddas and sistahs!
Hit Me
Hit me with questions, comments, concerns, happy to engage. Stay safe and be looking for The Ski Guide Manual when it comes out, November 1. Oh yeah!