Single strand rap with very large rings
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I've recently come across some anchors with massive rings (like 5" diameter). While they're convenient masterpoints, they suck for doing single strand rappels because a knot or even carabiner can pass through them. (edit: I'm particularly asking about double rope raps with a skinny tag line) |
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Figure 9 on the blocked side and clip the descending strand for a true reepschnur rappel, or simulrap |
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Mitch Monty wrote: The rings are large enough that any knot I could realistically tie can pass through them. It is effectively rapping on a bare sling. |
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Austin Donisan wrote: So the 5" wasn't an exaggeration and the biner would be able to pass through? That's huge. Do you have a photo or a route name or something? |
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Dan D wrote: Yes, a Rocklock could fit through them lengthwise. A bunch of routes in Squamish have various giants steel industrial rings on them stamped with absurd ratings like 7,000 KG WLL. |
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Another variation of the knot block is to add a biner which adds some bulk to it. but might not be a great idea if you're not 100% sure that it couldn't slide through. Clipping back to the rap line is a sure way to not die and I doubt that the knot would actually slide through anyway. using a butterfly does help though since it's less flat than an overhand or 8. A less common option would be to pickup a smooth operator which would let you rap on a stone knot, in this case your anchor can be as large as anything, even like a tree or something. I have one that I use a bit, but you do have to be more careful not to get it stuck. The benefit though is you can feel good using a super skinny pull chord while still rapping on a full strength rope. and if anything goes wrong while retrieving, you at least never had to let go of your lead line! |
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I would probably have the first person go down on a fixed single strand, then stay on rap and be my meat anchor as I unfix the line and rap on the other side. Kind of like simul-rapping, but you always have one person attached to an anchor. |
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The equivocation hitch might be of use, but it can be dangerous. YGD as I believe folks say around here. |
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A Beal Escaper would work in that situation, since it doesn't rely on any sort of block against the rings.(Not necessarily advocating use of the Escaper for everyday rappelling, just noting it would still work here). |
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JCM wrote: I don't have an Escaper, but I've heard a couple people say they couldn't get it to release. Have you ever experienced that? |
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Alpine butterfly or clove hitch at the halfway point, on the side you want to pull. Clip the biner onto your rap side, it’ll cinch around the ring when you weight the system. The biner will be loaded all funky, but it wouldn’t really matter for a rap. |
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Nathan Doyle wrote: Like JCM, that came to my mind as well for this application. And I also have no experience with one. What could go wrong, har har. ;) Still, getting it to release assumes a certain pull force with then unloading repeated up at the anchor. Rope-on-rock friction can interfere, preventing the force pulled below from getting to the anchor and / or the release from below getting fully up to the anchor. A really stretchy rope could make things worse. Sounds like it could be a nightmare not knowing whether the pull force and release are happening enough up top on each cycle. Probably stuff you / others know. If it is a known route with trivial rope-on-rock friction, I’d consider it. |
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I've always wondered about tying an overhand and clipping it to the ring before the first person goes down. Then when they get to the bottom they can secure the same strand they rapped on to the anchor or their belay loop (if on the ground) and the second can then single strand rap on the other side. |
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Alexandre Passos wrote: Why would one not just double strand rappel, in that case, assuming they had a tuber? |
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Alexandre Passos wrote: That would work fine. Seems totally unnecessary when a reepschnur rappel works fine, though. |
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Just use a rope grab to hold the rap side, clipped off to the pull side. |
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From Rickey's link about Reepschnurs:
If somebody wants to argue otherwise go ahead and try, but I'm not convinced right now.
almostrad wrote: I don't understand this. Can you elaborate or share a diagram? |
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Just find a sturdy 6" long stick. |
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Hi Austin, perhaps the first guy raps on fixed line. Ties off tag line to prevent rig from pulling through large ring? Don't know, interesting querry. |
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I can take a photo of an actual set up with gear tomorrow if needed. |
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almostrad wrote: I thought this wouldn't work when I read your first post, but now I think it would and it seems pretty clever if you happen to have a Micro with you. Phil, fixing the tag line for the 2nd rapeller is what I tried to suggest as a solution in my original post, but could have worded better. Having never tried it the problem I'd assume is the stretch in the tag line and fixing it at just the right length. |