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airscape
May 29, 2004, 10:51 PM
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I was wondering if anyone has used that method of rappeling where you tie a fig 8 knot in the middle of your rope clip a biner to it and thread on end of the rope thru the anchors and clip it to the biner and rap with the anchored end of the rope method? (maybe you know what I mean? it's on the petzl site and in the grigri booklet)
I was just wondering ,after a rappel when one pulls the rope to recover it and the biner reaches almost halfway down obviously gravity takes over and your biner falls to the ground (If for some reason you can't concider catching it), now if you have done a 30m rap won't your biner fall atleast 15m?? Now what? does one need to replace your fallen biner or is there a way to stop it from falling or am I just missing something?
I've never tried this technique though
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coldclimb
May 29, 2004, 10:58 PM
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I'm getting what you're saying, but why would you rap like that? It's just doing a single line rap when you could be doing a double, right? Add that to the fact that your biner is gonna drop, and you've got an overly complex system that seems pointless.
I dunno, but I wouldn't want my biners to drop that far that often.
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airscape
May 29, 2004, 10:59 PM
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I was thinking of doing a rap with my grigri, they say it can be done soooo let's do it :D
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galf
May 29, 2004, 11:31 PM
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I've done it multiple times for the purpose of rapping with the grigri.
It works, and the biner are in your hand by the time the rope starts accelerating.
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climbfrog
May 29, 2004, 11:35 PM
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What Galf said. You'll be fine! Just make sure you're at the middle of the rope when setting it up.
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andrewph
May 29, 2004, 11:39 PM
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if it realy became a worry you could have the rope pile right where the carabiner would land so it would cusion it.
but yeah it really will probably get to you before the speed of the rope is an issue!
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c_kryll
May 30, 2004, 1:19 AM
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I just spent a few minutes looking on Petzl's web site for a diagram of this setup but couldn't find it. Anyone got a link?
Chris
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euroford
May 30, 2004, 3:40 AM
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i've done it several times while rapping with my grigri (usually while rapping a building; at the end of the work day i'll rig this so i can pull my rope and leave without heading back up to the roof). it works just fine, though i would be carefull on really blocky routes as its something extra to get caught while pulling the ropes.
don't worry about dropping the biner. its dang close to the ground before anythign accelerates as mentioned above. essentially a non-issue.
btw: grigri's make pretty awsome rap devices if you want to take photos and stuff or, in my case if you inspect buildings on rapell. i suppose some dorks would also like them for rap bolting.... but reguardless, they have a nice controlled descent, allow quick and easy no hands stops, and as petzl illistrates can be easly rigged for use when you want to retrieve your rope.
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jefffski
May 30, 2004, 3:40 AM
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This is an interesting idea. it would have helped us last year rapping off of mt waddington. whenever we threw the ropes they became a tangled mess on the much less than vertical slopes. we wasted hours.
one solution (obvious now) would have been to rap with the ropes in a bag.
another solution, the one we used was for the first guy to rap on one line then when he was half way, the other members, still at the belay above, would tgrow the other rope down. it reduced the tangling, but not by much.
petzl method would have allowed us to rap on one rope, reducing the snarls to the minimum. obviously with a double rope rappel we would tie the figure 8 close to one end of one rope, and not to the middle.
thanks for passing the idea on.
jeff
i think i'll try it
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f_thomas
May 30, 2004, 6:46 AM
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After reading the instructions on Petzl's web site a couple of weeks ago I had the opportunity to give it a try this past weekend a couple of times while dismantling top rope anchors. It works, but I would recommend adding a biner to your belay loop witht he grigri connected with a short sling girth hitched to your harness - this will allow a bit more friction to be generated simply with the rap hand.
I don't really see the benefit of a single line rap over a more traditional friciton device with a double line such as an ATC. Other than an quick means to lock up to shoot pictures or ?? I think I would back that up though.
There is a post on one of the forums where a grigri was being used to lower down to climb and the rope broke going through the grigri for anunknown reasons. Freak accident = unfortuante deatha!
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airscape
May 30, 2004, 9:33 AM
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Cool I think I'll try it then.
That where the rope broke, I can't imagine that it was the grigri's fault, I wonder if it wasn't a defect in the rope??? I've never heard of a rope breaking before...
Thanks
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dredsovrn
May 30, 2004, 1:31 PM
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I am not sure I am following you all the way, but I have rapped/lowered myself off of an anchor with a tail of the rope tied to one side of the anchor. The anchor was a static line around a tree, and I use my weight to keep in even on rap. When I got down I pulled the rope, and the pulled the rest of the rope and anchor together. It worked great there, but I haven't been in a lot of situations where that would work again.
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bflank
May 30, 2004, 2:07 PM
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That's a common method for cavers who typically rappel on a rack. Caver's racks work more easily with a single rope than double. Useful as heck for a pull down cave trip where you won't need to go back up.
BTW, I always use a steel locking biner for this since it is a single point of failure with potentially fatal results for a failure.
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merock
May 30, 2004, 2:31 PM
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In reply to: I don't really see the benefit of a single line rap over a more traditional friciton device with a double line such as an ATC. Other than an quick means to lock up to shoot pictures or ?? I think I would back that up though.
it's very good for shooting phots and also to do simul-rap.....
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rescueman
May 30, 2004, 10:27 PM
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In reply to: I always use a steel locking biner for this since it is a single point of failure with potentially fatal results for a failure.
Also, be careful that the midline knot can't get sucked into the rap anchor, which will not only make it difficult or impossible to pull down but could also side-load the midline biner against the rap biner/maillon and possibly open the gate and release the rope. A maillon might be better than a biner for the midline connection.
Arborists use a similar technique to SRT climb a tree with a releasable SRT rap, but they use a running bowline midline with no metal connector.
In reply to: Merock wrote: it's very good for shooting phots and also to do simul-rap.....
- Robert
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rescueman
May 30, 2004, 10:33 PM
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In reply to: There is a post on one of the forums where a grigri was being used to lower down to climb and the rope broke going through the grigri for anunknown reasons. Freak accident = unfortuante deatha!
Not unknown at all. A piece of sharp crystaline rhyolite (the granitic formation they were climbing on) got sucked into the Grigri, which was lying on the ground on a pack, jambed into the cam and tore a line along the sheath before it finally caught the core bundles and severed the loaded rope as someone was being lowered, dropping the climber 163' to his death.
- Robert
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merock
May 31, 2004, 5:15 AM
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In reply to: In reply to: I always use a steel locking biner for this since it is a single point of failure with potentially fatal results for a failure. Also, be careful that the midline knot can't get sucked into the rap anchor, which will not only make it difficult or impossible to pull down but could also side-load the midline biner against the rap biner/maillon and possibly open the gate and release the rope. A maillon might be better than a biner for the midline connection. Arborists use a similar technique to SRT climb a tree with a releasable SRT rap, but they use a running bowline midline with no metal connector. In reply to: Merock wrote: it's very good for shooting phots and also to do simul-rap..... For a simul rap there's no need to cross link the two sides of the rope, each person counterweights the other. - Robert
werd.... I was just talking about using a gri gri for a single line rap.... It would be redundant to cross link the two sides of the rope....
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airscape
May 31, 2004, 2:20 PM
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That's quite hectic about the piece of crystal that got sucked into the grigri, makes one realize that you shouldn't let your gear lie in the dirt.
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allenperry
May 31, 2004, 4:22 PM
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In reply to: btw: grigri's make pretty awsome rap devices if you want to take photos and stuff or, in my case if you inspect buildings on rapell. i suppose some dorks would also like them for rap bolting.... but reguardless, they have a nice controlled descent, allow quick and easy no hands stops, and as petzl illistrates can be easly rigged for use when you want to retrieve your rope.
As a reminder: Never take your hand off the brake side of the rope. If you want to go no-hands in mid-rappel, tie off the brake (e.g. Mule knot w/overhand)
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slacklinejoe
May 31, 2004, 8:31 PM
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In reply to: As a reminder: Never take your hand off the brake side of the rope. If you want to go no-hands in mid-rappel, tie off the brake (e.g. Mule knot w/overhand)
Agreed, I was taking photos this weekend and I just used a autoblock klehmist knot (spelling?) hooked to rope on my belay hand from my leg strap and extended the device with a 2' sling. Redundant and possibly unnecessary but I was doing a lot of hanging so it made sense. That was my first gri-gri rappel - specifically what I bought it for, and it did what I hoped it would.
Worked slick although the gri-gri heated up much faster than my ATC doing something similar. I wasn't even going fast.
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rescueman
May 31, 2004, 9:17 PM
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In reply to: I just used a autoblock klehmist knot (spelling?) hooked to rope on my belay hand from my leg strap and extended the device with a 2' sling. That was my first gri-gri rappel - specifically what I bought it for, and it did what I hoped it would. Worked slick although the gri-gri heated up much faster than my ATC doing something similar.
If you're using an autoblock backup, then why do you need the Grigri, particulary if it can't handle the friction? Use your ATC with the autoblock and you can stop and shoot just as well.
By the way the Klemheist and autoblock are not the same friction hitch:
Klemheist
http://www.ozultimate.com/...mheist/klemheist.jpg
Autoblock
http://www.chockstone.org/...Tips/RapBackup2s.jpg
The autoblock can also be connected to the biner at both ends instead of girth-hitching.
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slacklinejoe
May 31, 2004, 9:22 PM
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The autoblock wasn't really used, just so I could let go without worrying about it since it was my first time letting go of the rope while rappelling.
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rescueman
May 31, 2004, 9:42 PM
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In reply to: The autoblock wasn't really used, just so I could let go without worrying about it since it was my first time letting go of the rope while rappelling.
Well, what's the point of using it if it's "not really used"? That's like paddlers putting on their PFD but not zipping it up. It's just there but not being used in any way that might save their arse, and in fact might contribute to their drowning because it's flopping up around their face when they go overboard.
If you tie an autoblock as a backup, then make sure it's positioned properly so it can't contact the descender and make sure it's set at each lock-off. Otherwise don't bother using it - it's just one more thing to get in your way.
- Robert
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