grigri rappel off partners atc
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Somebody mentioned this to me this weekend as an option for grigri raps whithout a biner block or reepschnurr. Trying to think through it. Rope is through rap rings, then partner loads atc below rings, presumably extended and backed up with an autoblock. Below that, grigri is loaded on a single strand. The idea is the atc would block the rope from lowering under load from grigri. I haven't tried it, though since the strands would be loaded asymmetrically, and and atc guide or similar doesn't lock the rope except by loading the break side strands, I could see the grigri pulling the rope through the atc. It doesn't seem like a foolproof method for rapping in this situation, however, I'm willing to credit the idea as not imminently deadly. Any thoughts? Is somebody using this method gonna die? I don't think I would do it, personally. |
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You'd need to really trust your partner to control rope speed through the ATC and prevent slip through the rap rings. Sounds like another easily avoidable way to die on rap. |
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Here's a good reason why not to try anything like you are attemtping to describe. Just keep it as simple as possible. |
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What you have described is the same as simul-rapping, except that your partner stays put at the anchor. No reason it can't work, but it would be crucial that you both understand the sequence of events you're planning on doing. If your partner also expects to rap a single strand with you as a counterweight, but you reach the anchor below and come off rappel (eliminating the counterweight), they will fall to their death. |
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Think the mentioned setup is that person with ATC sets up their rappel at the top of the rope, right below the anchor. Locks it off with auto-block and hand. So the rope is effectively blocked from slipping in EITHER direction. |
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No. Stop. No. Just fix one strand of the rope to the anchor after threading the rope through the rap rings, send the grigri climber down that strand, second climber then will undo the fixed knot and rap normally with his/her atc. Using your partner as a biner block makes no sense and makes it harder for them to assist should anything go wrong. Using a biner block with two climbers when at least one has an atc makes no sense and introduces additional unnecessary failure modes. |
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This was actually published in an article about going lighter not that long ago on one of the climbing magazine websites I believe. At least, that's how I found it although I can't seem to find it again. In fact I might've originally seen it on the MP front page. It's basically as you describe, partner sets up rap, you gri-gri in to 1 strand and rappell while their device is blocking it. I'm going nuts trying to find it, I know it's out there somewhere |
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Can't see climbers who are "going lighter" having a grigri |
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This wasn't describing simul-rappeling. Rather, it's the partner with an atc staying at the top and acting as the block, then rappeling once the grigri rappel is off at the next station. I am aware that if my partner is up there, they could simply fix the rope, then remove the knot. I'm just asking about this specific technique. I'm not planning on doing it myself, just wanted to crowd source some additional failure cases. |
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Ah! I misunderstood the OP. You are saying the partner with the ATC goes onto rappel with BOTH strands, then the partner with the gri-gri single rope raps BELOW that. Yes it could work. I'd probably also add a biner block just so the partner with the ATC didn't actually have to do anything to control the ropes. Then it's effectively the same as stacking rappels, but with 2 different rappel methods. |
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Chris Reyes wrote: thanks, that must've been where they had seen it. well at least it has one other source. after trying biner blocks for a day i decided to just ditch the grigri for multipitch and use my megajul instead. I think the 'going lighter' thing is a misnomer. i see the merit of a team having one grigri and one atc guide, rather than two atcs and a grigri if the leaders want an assisted breaking device. |
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You can do it, but you need to back up the ATC with a mule knot/auto block. I'd say that a mule knot would be best. It overly complicates things though as now the person with the ATC needs to remember to attach the second strand to their ATC. In a lot of situations that is a simple and deadly mistake to make. Why not set up a carabiner block for the Grigri and remove it for the ATC? Even then, the only reason I would remove it is if I was worried about the carabiner catching when I pull the rope. Another solution is to tie the person in and lower them on the ATC. Or to fix one strand to the anchor via an overhand on a bite and a locker and have the Grigri rapell that. Or simul-rappel with auto-block backups. I don't see any benefit to the situation and at least one big reason to avoid it. |
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Chris Blatchley wrote: The ATC won’t block the rope, it’s the autoblock that’s doing the blocking. This is pretty easy to test, isn’t it? Just hang a rope in your garage (or apartment, van, bridge, whatever your living situation), put an ATC on both strands, put a Grigri on a single strand below it and then bounce on the Grigri. Without doing this myself, I’m pretty sure the rope will slip through the ATC without the autoblock. Which begs the question, would I personally trust just an autoblock to prevent the two strands from slipping pass each other when I'm hanging all my weight on a single strand? Just use a stone knot to fix the rope, and the last person with the ATC untie the stone knot and rap on both strands. It's a tried and tested method. Takes seconds to tie and untie. |
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This image from the OR article looks unsafe to me. Two strands of rope going through the ATC but the unweighted strand (not the one the ATC is descending) appears to be totally unblocked and could slip through the ATC. |
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Tie knot on bight. Clip knot to partner. Use partner block. No partner will fit through a rap ring. |
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Chris Blatchley wrote: For this specific technique: No. Stop. No. I would imagine that the failure cases would be low because there's little likelihood that the average climber is going to come up with this and those who have seen the article while in the go faster and lighter phase would probably be able to find other methods that are faster and lighter than this. |
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Ryan Bowen wrote: Tie knot on bight. Clip knot to anchor. Use anchor block. No anchor will fit through a rap ring. |
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Chris Reyes wrote: i think this article is completely moronic. it is basically complicating things for the sake of being cute. |
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The only vague reason I could see for doing this is "This system has the added benefit of allowing both partners to double check the set up." (via the article), but holy crap does it seem forced. Fixing one of the sides, per Kevin's emphasis, can just be done below the preloaded tuber. Rappelers check each other, Grigri rapper gets down, line is unfixed and tuber rapper raps. |