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bearbreeder
Dec 21, 2012, 10:05 PM
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http://www.youtube.com/...ed&v=3T4FT2SHFLo
its canyoneering, but its still highly relevant
http://www.bogley.com/...Rubio-Canyon-60-fall
On Thalehaha Falls in Rubio Canyon, Altadena, CA, my buddy rigged his autoblock incorrectly. When he slipped on the mossy face, he sadly instinctively let go of the brake line. He fell 60'. It was miraculous that he walked away with nothing but deep bruises. Credit the shallow pool, slight slope of the face, landing on his butt, and the redirection the autoblock created which contributed some friction.
I actually haven't rappelled first in ages, always the leader now and checking others' rigging. But he wanted me to get pics and video of his coming down. He has done about 25 rappels total in his canyoneering career, including the 100/120' Leontine falls in the same canyon. I was concerned, I cautioned him, but he insisted. So I went down.
His mistake, as verified by still from the video, was that he didn't clip his autoblock 'biner into the leg loop. Rather it was above the leg loop. Of course it slid up and couldn't cinch the brake line.
In hindsight, a fireman's belay would have prevented this. Such is the risk of a 2 man descent and the desire to get video/pics. I don't know if I should have insisted on going last, or forgone the pics and done a fireman's belay, or done like I did and granted that a canyoneer is responsible for themselves at some point in their career.
Thankfully his ego is the most bruised of all.
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acorneau
Dec 22, 2012, 2:34 AM
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One lucky mo-fo.
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Gmburns2000
Dec 22, 2012, 3:28 AM
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bearbreeder wrote: http://www.youtube.com/...ed&v=3T4FT2SHFLo its canyoneering, but its still highly relevant http://www.bogley.com/...Rubio-Canyon-60-fall On Thalehaha Falls in Rubio Canyon, Altadena, CA, my buddy rigged his autoblock incorrectly. When he slipped on the mossy face, he sadly instinctively let go of the brake line. He fell 60'. It was miraculous that he walked away with nothing but deep bruises. Credit the shallow pool, slight slope of the face, landing on his butt, and the redirection the autoblock created which contributed some friction.
I actually haven't rappelled first in ages, always the leader now and checking others' rigging. But he wanted me to get pics and video of his coming down. He has done about 25 rappels total in his canyoneering career, including the 100/120' Leontine falls in the same canyon. I was concerned, I cautioned him, but he insisted. So I went down.
His mistake, as verified by still from the video, was that he didn't clip his autoblock 'biner into the leg loop. Rather it was above the leg loop. Of course it slid up and couldn't cinch the brake line.
In hindsight, a fireman's belay would have prevented this. Such is the risk of a 2 man descent and the desire to get video/pics. I don't know if I should have insisted on going last, or forgone the pics and done a fireman's belay, or done like I did and granted that a canyoneer is responsible for themselves at some point in their career.
Thankfully his ego is the most bruised of all.
Nothing to do with the autoblock - he let go of the freakin' rope.
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patto
Dec 22, 2012, 4:32 AM
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Gmburns2000 wrote: Nothing to do with the autoblock - he let go of the freakin' rope.
Which is more likely if one has the assumption that their autoblock will offer protection if you let go of the rope.
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rgold
Dec 22, 2012, 3:56 PM
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Right. It used to be an absolute cardinal rule that you never took the brake hand off the rappel line, unless you had wound the brake strand five times around your thigh. Autoblocks have changed all that, and this isn't the first accident involving an autoblock failure. At least one such failure has killed an experienced climber.
The fact of the matter is that autoblocks don't always work. If you wind them really tight, they make rappelling a pain. If you wrap them too loose, they may not grab, and they won't grab at all unless you let go of them. If you don't get good spacing between the knot and the rap device, they won't grab. Setups that appear to work may suddenly release if the rappeller raises their leg.
Autoblocks are basically there to save the climber in case something knocks them out, but if something does knock them out, then you have an unconscious climber hanging on the rappel line, with the potential for a long and complicated rescue.
I'm not saying autoblocks are worthless, but I think a more nuanced approach, rather than always using them, is preferable. In particular, a "fireman's belay" for all but the first person down seems to me to make far more sense.
On the other hand, extending the rap device to eye level seems to me to be a really good idea, whether you are combining that with an autoblock or not. You get a bit more friction out of the rappel device and can easily use both hands for braking. (Having one hand above the device is pretty dumb if you think about it...) You can easily throw on an autoblock at any time if you see the need for one.
There are downsides to an extended device. It is harder to start rappels with low anchors, and the device can grate disturbingly against the lips of overhangs you rap over. You have to be very careful to keep long hair out of the device and not let a hot device touch bare skin (say on your shoulder). All in all, I think the plusses outweigh the minuses though, and a number of very experienced climbers I've encountered seem to agree. They rappel with an extended device whether or not they are using an autoblock.
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bearbreeder
Dec 22, 2012, 4:30 PM
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keep both hands below the device ...
its really that simple
the autoblock doesnt make up for poor rap technique
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namoclimber
Dec 22, 2012, 6:40 PM
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Is this a common practice to not use double rope rap when available.
If you let go of the brake hand this will happen.
Lucky as hell it ended the way it did.
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marc801
Dec 22, 2012, 6:53 PM
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namoclimber wrote: Is this a common practice to not use double rope rap when available.
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socalclimber
Dec 23, 2012, 5:16 AM
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It's simple. Close the system. If I even think that going over the edge is going to be tricky, I just pull up 10 feet of rope and tie a knot in it. That way if I blow it on the edge, I'm not going very far.
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healyje
Dec 23, 2012, 10:54 AM
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Rgold, I think you're being a bit too kind in this instance and Gmburns2000 is pretty spot on and the bottom line is this person clearly wasn't competent to be doing that rap.
I also believe this has nothing whatsoever to do with an autoblock and everything to do about not having the requisite experience to maintain his brake hand on the rope under those conditions.
He's lucky to be alive.
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patto
Dec 23, 2012, 1:35 PM
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If there was an Rgold fanclub I would be a Gold Star Member. Like usual I believe he hits the nail on the head.
There is a whole lot of evidence that points towards the ineffectiveness of autoblocks in panic situations. There are also numerous failures of incorrectly rigged autoblocks or other failures to stop the descent.
The problem arises because the autoblock is ROUTINELY used as a reliable backup when in reality there is a really isn't the case. Extending the device significantly improves the reliability of the autoblock. Though firemans is almost always the best option.
healyje wrote: I also believe this has nothing whatsoever to do with an autoblock and everything to do about not having the requisite experience to maintain his brake hand on the rope under those conditions.
If you think the autoblock will reliably operate as a second hand then your instinct to hold onto the rope will likely decrease. In contrast if you consider it death to let go then in all probability you wont.
(Next week I'm going for a 8 days of canyoning with a largish group of mixed abilities. There is a culture among some of excessive use of the autoblock. This is something I wish to change or at least insist on fireman's belays as well.)
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wivanoff
Dec 23, 2012, 1:43 PM
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marc801 wrote: namoclimber wrote: Is this a common practice to not use double rope rap when available. In canyoneering, a double rope rap is almost never used except by the clueless. Typically you use a 9mm static rap line anchored with a biner block, and a 6mm or 7mm retrieval line. Both are payed out from rope buckets as needed by the first person down, thus avoiding having to deal with 70m of rope all over the place for an 8m drop.
LOL.... Using a 70m rope AND a retrieval line for an 8m drop sounds pretty clueless
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rgold
Dec 23, 2012, 3:07 PM
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healyje wrote: Rgold, I think you're being a bit too kind in this instance and Gmburns2000 is pretty spot on and the bottom line is this person clearly wasn't competent to be doing that rap. I also believe this has nothing whatsoever to do with an autoblock and everything to do about not having the requisite experience to maintain his brake hand on the rope under those conditions. He's lucky to be alive.
Joe, I almost agree with what you are saying. Letting go of the brake strand like that would have been a sign of total incompetence BITD.
But nowadays autoblocks have convinced a large proportion of climbers that they can let go whenever they want---I see it all the time, among both the inexperienced and the otherwise experienced, and part of my post was meant to convey my opinion that autoblocks are not reliable enough to be used for casual release of the brake strand. They are supposed to be an emergency backup, not an everyday substitute for leg wraps, which are about as foolproof as anything in climbing can be.
The one thing I disagree with is your statement that the accident has nothing to do with the failure of an autoblock. It is beyond contention that the autoblock failed, probably because it was set up too close to the rap device. If the autoblock had held, there would have been no incident at all. Of course he should never have let go of the brake strand like that to begin with, but once he made that potentially fatal error, the autoblock indeed failed to function.
Full agreement that the guy is lucky to have walked away from that one.
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billl7
Dec 23, 2012, 5:57 PM
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Wow!
There was also a wet-rap-with-autoblock accident in Zion, unfortunately fatal:
Man dies rapping in Zion
In the Zion case, if understood correctly which may not be the case, it appears the too-close autoblock jammed in the rap device preventing further lowering. Pushing the autoblock down the rope has been my limited experience and I think this is normally the conservative assumption to make about the failure mode.
A fireman's / caver's belay has its issues too. The person giving the backup belay needs to be 100% attentive the whole rap and understand they need to pull down to apply braking.
I emphasize that because our very-frequent imprinting (and so the common instinct) is that resisting rope movement is enough: instinct that becomes ingrained by catching a fall, by lowering someone from a climb, or by braking your own rap. But simply resisting rope movement is no good when actually needing to save someone with a fireman's / caver's belay.
Better to not rely on instinct when giving a fireman's / caver's belay. I'll go a step further and say it is best to periodically practice holding a fall with a fireman's / caver's belay in hopes of negating that other instinct.
Bill L
Edit: P.S. It took about 3 seconds (maybe 2) from the time the person rapping first slips to the sound of the splash when he decks. Three seconds seems a long time. But I still doubt that's enough time for a person belaying below and relying on the common instinct to
a) realize it's time to engage the fireman's / caver's belay (first second);
b) realize that gripping the rope isn't helping (second second), and
c) realize that just gripping the rope harder also is not doing the job (third second).
(This post was edited by billl7 on Dec 23, 2012, 6:31 PM)
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bearbreeder
Dec 23, 2012, 7:38 PM
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socalclimber wrote: It's simple. Close the system. If I even think that going over the edge is going to be tricky, I just pull up 10 feet of rope and tie a knot in it. That way if I blow it on the edge, I'm not going very far.
i believe the guy was down more than 10 feet when the fall happened ...
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patto
Dec 23, 2012, 7:47 PM
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Do people really think that simply gripping the rappel rope in a fireman's belay will slow the climber? Surely not!? Anybody who doesn't know how to give a fireman's belay shouldn't be doing so. If I am showing an inexperience person how to rap, I would normally show them directly but pulling on the rope. I can't disagree with your idea of at least testing and knowing how to use the fireman's belay.
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billl7
Dec 23, 2012, 7:57 PM
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patto wrote: Do people really think that simply gripping the rappel rope in a fireman's belay will slow the climber?
At the same time, I've seen many folks holding the rope while fully focused in a conversation with someone next to them or doing something else. Leads me to believe they haven't thought about it or are just inattentive.
About the only hope in that case is instinct.
Bill L
Edit: I shouldn't have said I've seen "many". I have seen enough where I think it is worth emphasizing when discussing the fireman's belay.
(This post was edited by billl7 on Dec 23, 2012, 8:00 PM)
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bearbreeder
Dec 23, 2012, 7:59 PM
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the autoblock wasnt clipped in period ...
thats why it didnt work ... the rappeller failed to test his system before going down ...
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billl7
Dec 23, 2012, 8:12 PM
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bearbreeder wrote: the autoblock wasnt clipped in period ...
That said, it looks like he had not much more than one full rap around the rope.
Edit: 0:58 shows the attachment to the leg loop.
(This post was edited by billl7 on Dec 23, 2012, 8:15 PM)
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bearbreeder
Dec 23, 2012, 8:19 PM
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billl7 wrote: bearbreeder wrote: the autoblock wasnt clipped in period ... Looks to me like it was attached to the leg loop and the rope. See 1:26 for a shot of the autoblock's attachment to the brake strand. That said, it looks like he had not much more than one full rap around the rope. Edit: 0:58 shows the attachment to the leg loop.
from the victim and his partner
His mistake, as verified by still from the video, was that he didn't clip his autoblock 'biner into the leg loop. Rather it was above the leg loop. Of course it slid up and couldn't cinch the brake line.
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billl7
Dec 23, 2012, 8:23 PM
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billl7
Dec 23, 2012, 8:44 PM
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Okay - it's been a while since I've used an autoblock. Probably this set up: girth the cord to the leg, wrap around the brake strand some number of times, then clip back into the leg loop. (Except it was not clipped to the leg loop. Edit: Perhaps instead it was clipped back on the autoblock cord itself which kept the cord wrapped around the brake strand.)
Geesh: I'd have left the above 'deleted' post if I'd realized a blank entry would be left there. It was just me scrambling around trying to make sense of how the autoblock was attached to the harness and to the brake strand.
(This post was edited by billl7 on Dec 23, 2012, 9:47 PM)
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moose_droppings
Dec 23, 2012, 10:21 PM
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billl7 wrote: A fireman's / caver's belay has its issues too...
Yep, if they're getting swarmed by a bunch of bees, or a loose block tumbles their way, don't count on them. Line of sight isn't always there either.
That said, I use an autoblock below the device a lot, but never rely on it as an emergency tool. Mostly for stopping and untangling ropes, fiddling with stuck gear, taking a pic or whatever. I make sure it is engaged before removing my hands from below the device and if I'll be hanging for a while I'll toss in a few leg wraps.
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billl7
Dec 24, 2012, 1:00 AM
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Right. The explanation in that thread for why the autoblock didn't work was that the final clipping to the leg loop should be "at the block's girth" but was not. It was forward on the leg loop where it then "slid up [along the leg loop] and couldn't cinch".
This guide teaches that clipping forward of the girth is fine.
In David Fasulo's "Self-Rescue" book (1996 - it was recently revised), several illustrations show clipping rear-ward of the girth.
Is it really that critical whether the biner is clipped forward, at, or rear-ward of the girth? Can an autoblock in this application really be that sensitive?
Bill L
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wivanoff
Dec 24, 2012, 1:57 AM
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billl7 wrote: Right. The explanation in that thread for why the autoblock didn't work was that the final clipping to the leg loop should be "at the block's girth" but was not. It was forward on the leg loop where it then "slid up [along the leg loop] and couldn't cinch". <snip> Is it really that critical whether the biner is clipped forward, at, or rear-ward of the girth? Can an autoblock in this application really be that sensitive?
No, I have not seen that to be the case. Although, I put them on the same side of the buckle when I do that. Usually extend the rappel device, too.
I'm not convinced of the explanation given above. It looked to me like you were right: there were few wraps on the French Prusik. Maybe only one full wrap?
I would guess that coupled with the French Prusik being too close to the ATC, a regular ATC on a thiner single rope, not testing his setup and "instinctively" letting go of the brake hand all contributed to a near disaster.
Difficult to see the actual setup in that video. But, the photographer DID get some nice shots of the Camelback drinking tube..... that was very helpful
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bearbreeder
Dec 24, 2012, 3:07 AM
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you really cant see anything from the photo ... but i believe that they mean it was clipped above the leg loop, not within it at all ... the autoblock would not hold and will probably go right against the ATC ...
if you are going to clip a backup, do so on the INSIDE of the leg loop, not the buckle side if it has speed buckles ..
even better extend the atc off a sling and clip the backup to your belay loop
failure to test and poor rappel technique is the root cause of the accident IMO
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billl7
Dec 24, 2012, 3:25 AM
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bearbreeder wrote: you really cant see anything from the photo ... but i believe that they mean it was clipped above the leg loop, not within it at all ...
That's what I initially thought too. I later realized for me the word "above" was misleading. The marked-up photo from the forum link is pretty clear though. I've embedded in this photo the related text from the forum. The biner was clipped back to the leg loop.
(This post was edited by billl7 on Dec 24, 2012, 3:26 AM)
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milesenoell
Dec 24, 2012, 6:47 PM
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If that's the case then let me venture the question: How likely is a correctly rigged autoblock to fail?
Whether it was rigged correctly or not, I thought they were always suspect, but I've never heard anybody try to quantify it.
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billl7
Dec 24, 2012, 6:51 PM
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On the topic of whether the autoblock might have ridden up agains the ATC and so been pushed down by the ATC during the fall:
The autoblock was a rather tight assembly down at the leg loop; the shiney cylinder is the biner clipped to the leg loop and the yellow is the autoblock cord:
Here's a cleaner shot of part of unfortunately just part of the rig:
At the beginning of the fall, it appears to be appreciably below the ATC; he's already let go of the break strand:
Well into the fall, the autoblock still appears to be appreciably below the ATC. If one imagines where the inflection point of the rope is behind his arm, that is about where the ATC is:
I'm willing to assume there was sufficient separation between the ATC and the autoblock ... although I'm thinking more separation would be better.
Bill L
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billl7
Dec 24, 2012, 7:20 PM
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milesenoell wrote: If that's the case then let me venture the question: How likely is a correctly rigged autoblock to fail?
Good point. At the same time, it's one thing to say that a bowline is correctly tied. Or a double fishermans is correctly tied. An autoblock has variables (some listed below) that necessitates something more than "is this the config I am used to seeing?"
(above, I'm probably saying things that you already include in "correctly rigged" - just want to be explicit.)
In my limited experience with an autoblock, it seemed to be a kind of balancing act between too loose to catch and too tight to be smoothly slid down by the hand. The consequences of too loose are obvious. For too tight, it's both an annoyance and a distraction during the rap. Maybe this balancing act is why some in this thread have emphasized testing the set up to see if it seems to catch (albeit in the config of a given pre-rap test) - to get the balancing act just right.
Assuming the ATC didn't push the autoblock down during this fall, perhaps the failure here has to do with one or more of the following - any of which will reduce the chance that the autoblock is going to grab on its own:
* the number of wraps around the rope being too few (perhaps combined with the ends of the cord not being held in close proximity or crossed (akin to kleimheist)?);
* the relative diameters of the cord to the rope; the author of the video indicated the rope was a 9.0 mm rope; the coils of an oversized cord will not cinch down on a relatively small diameter rope as readily as a cord of lesser diameter;
* the type of rope; Blue Water Canyon Line spec info indicates it has a 100% Technora Aramid sheath for excellent cut resistance (relatively slick?);
* edit to add: too short of a cord may cause the biner to be in contact with the rope - perhaps that could hinder the autoblock from grabbing on its own; perhaps this in itself is a good reason to wrap towards the ATC and then clip back on the opposite side of the girth hitch.
Is there something else (again, assuming the ATC did not push down the autoblock)?
Bill L
(This post was edited by billl7 on Dec 24, 2012, 7:24 PM)
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bearbreeder
Dec 24, 2012, 7:49 PM
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a correctly tied and spaced autoblock once weighted should not "fail" below the device as the weight it needs to hold is minimal ... but as everyone knows when yr shifting around hands free, things can get caught or bumped ...
the autoblock is one of the easier friction hitches to release ... so be aware of that ... if you are truly going hands free a quick overhand knot will prevent you from going SPLAT !!!
also remember on a single strand that youll need more wraps ...
IMO a kleimheist is a "better" knot for this as you can easily tie it with slings ...
the "best" way to use a fiction hitch is to extend the rappel on a sling (use a knot to shorten it) and put the hitch on the belay loop ... this makes the spacing much easier, helps prevent you from screwing up your clipping, and should you be totally and utterly stupid and screw up your rappel setup, the hitch MAY hold you without inverting ...
its also much easier to control the hitch and keep BOTH hands below the device this way ...
personally i use a mammut alpine smart these days ...
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cracklover
Dec 24, 2012, 8:00 PM
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billl7 wrote: Edit: P.S. It took about 3 seconds (maybe 2) from the time the person rapping first slips to the sound of the splash when he decks. Three seconds seems a long time. But I still doubt that's enough time for a person belaying below and relying on the common instinct to a) realize it's time to engage the fireman's / caver's belay (first second); b) realize that gripping the rope isn't helping (second second), and c) realize that just gripping the rope harder also is not doing the job (third second).
I'm sorry, but that's complete nonsense. Anyone with experience giving a fireman's belay to a rappeller can stop a falling climber in way less time than that. I've only needed to put the breaks on someone once - it was an inexperienced climber doing around a 30 foot rappel. She lost control of the rope just as she was going over an awkward lip. I caught her so fast that I think that by the time she got her hand back on the device a split second later, she wasn't entirely sure she had ever lost control. Of course that might have been plenty of time (especially with falling out of control and the loss of sense of what's where that would follow) that had I not braked the line she may never have regained control before decking.
Bottom line is that for a fully competent person giving a fireman's belay, keeping your partner off the ground is totally trivial.
GO
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billl7
Dec 24, 2012, 8:04 PM
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cracklover wrote: billl7 wrote: Edit: P.S. It took about 3 seconds (maybe 2) from the time the person rapping first slips to the sound of the splash when he decks. Three seconds seems a long time. But I still doubt that's enough time for a person belaying below and relying on the common instinct to a) realize it's time to engage the fireman's / caver's belay (first second); b) realize that gripping the rope isn't helping (second second), and c) realize that just gripping the rope harder also is not doing the job (third second). I'm sorry, but that's complete nonsense.
Bill L
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socalclimber
Dec 24, 2012, 9:04 PM
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bearbreeder wrote: socalclimber wrote: It's simple. Close the system. If I even think that going over the edge is going to be tricky, I just pull up 10 feet of rope and tie a knot in it. That way if I blow it on the edge, I'm not going very far. i believe the guy was down more than 10 feet when the fall happened ...
Well, then you pull up more than 10 feet. Anything to keep you off the deck.
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billl7
Dec 24, 2012, 10:03 PM
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Occasionally I'll tie off with a mule knot and overhand, slip over the edge until hanging, and then release it to then rap.
Reading the linked canyoneering forum, some are suggesting taboggan'ing down as in sit on your butt or hip and slide on rappel. For raps on a wet & polished slot canyon, that doesn't sound too bad in terms of stability.
(This post was edited by billl7 on Dec 24, 2012, 10:03 PM)
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socalclimber
Dec 24, 2012, 10:30 PM
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I agree, that's not a bad idea. I'm still baffled why people cannot seem to understand the concept of closing the system when necessary.
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marc801
Dec 24, 2012, 11:31 PM
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socalclimber wrote: I'm still baffled why people cannot seem to understand the concept of closing the system when necessary.
Here's a hint: learn how to rappel correctly.
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socalclimber
Dec 24, 2012, 11:39 PM
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marc801 wrote: socalclimber wrote: I'm still baffled why people cannot seem to understand the concept of closing the system when necessary. I'm baffled by the amount of analysis and navel gazing over secondary crap like autoblocks in this thread for an accident that is the result of pure incompetence. Here's a hint: learn how to rappel correctly.
Yeah, well that would include closing the system when required.
(This post was edited by socalclimber on Dec 24, 2012, 11:48 PM)
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billl7
Dec 25, 2012, 12:41 AM
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marc801 wrote: I'm baffled by the amount of analysis and navel gazing over secondary crap like autoblocks ...
Folks commonly use backups to rappel. This one failed to perform in circumstances that would lead most who use them to rig one. Seems natural to want to understand the rigging mistakes which were poorly understand from at least 10 months ago up until as recently as about 10 posts ago (some would probably argue the problem is still not well understood and may never be).
Edit: The above statement that the rigging mistake was poorly understood 10 months ago may be wrong; see this post for tests that demonstrate the effect of clipping before or after the girth hitch.
marc801 wrote: ... for an accident that is the result of pure incompetence.
Right. Folks shouldn't overlook the fact that Matt was not ready to do that particular rap without active control by a competent person.
Perhaps RC.com needs a crusade regarding threads that present pure incompetence, that they must stay on topic. I'm sure the rest of us would be fine with starting a separate thread to dig into the details.
Bill L
(This post was edited by billl7 on Dec 27, 2012, 5:28 PM)
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cracklover
Dec 25, 2012, 1:00 AM
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billl7 wrote: cracklover wrote: billl7 wrote: Edit: P.S. It took about 3 seconds (maybe 2) from the time the person rapping first slips to the sound of the splash when he decks. Three seconds seems a long time. But I still doubt that's enough time for a person belaying below and relying on the common instinct to a) realize it's time to engage the fireman's / caver's belay (first second); b) realize that gripping the rope isn't helping (second second), and c) realize that just gripping the rope harder also is not doing the job (third second). I'm sorry, but that's complete nonsense. In light of what I underlined above, what part of the above is complete nonsense? Bill L
Just what I said - you see the person start to fall, so you pull on the rope. It's nearly instantaneous from the moment you notice something wrong up above you. Really from the moment you start pulling, they'll start slowing down.
I don't understand what you mean about realizing that gripping the rope (or gripping the rope harder) isn't working. If the person knows how to give a fireman's belay, why would they think that how hard they grip the rope has anything to do with anything? When you're giving a fireman's, you always have a full grip on the rope until the person's safe or asks you to get off fireman's.
GO
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billl7
Dec 25, 2012, 1:50 AM
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The difference is you are talking about the person who has thought about it and keeps those thoughts in mind while providing a cavers belay. Or someone who has a strong mechanical understanding during each situation regardless of their experience level.
I refer to the person who hasn't really thought about the difference between i) a caver's belay and ii) belaying a climber or stopping their own rap. Sure, they've seen someone hold the rope but that is all.
The term myopic comes to mind. But that is not totally fair. In a moment of panic - when your partner has lost control on rap, folks who haven't thought it out are likely to fall back to the more exercised instincts (i.e., that you just need to keep the rope from moving).
I'll confess that my concerns about this may have been warped over years of teaching folks new to multi-pitch. Most of them were doing it for a one-time experience and were in various states of just learning how to belay and rappel. Perhaps a steady diet of that takes its toll.
Bill L
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milesenoell
Dec 26, 2012, 4:00 PM
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The one time I have actually stopped someone with a fireman's belay was with a BIG guy on a brand new and pretty skinny line so I opted to loop the end under my butt and sit into the loop for tension. While I've never really examined this approach for weaknesses it does seem to make it very intuitive, since any motions the person on the ground makes to get out of the way of the way results in tension to stop the fall.
Sorry if this is taking us off subject, but I figured I'd toss it out there to see what you folks make of it.
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6pacfershur
Dec 26, 2012, 6:04 PM
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where was all the criticism and analysis a few weeks ago when well-known rockstud john long fucked up the fundamental procedure of tying in? i look forward to many pages of validation, rationalization and self-justification.............
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bearbreeder
Dec 26, 2012, 6:15 PM
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there was plenty of that and death of the bowline stuff on the web ...
in this case a simple test of the rap prior and proper rap technique will help ya
in mister longs case there was a total failure of the self/partner check ... and getting distracted likely by hawt chicks
you can "learn" by screwing up yourself .. or from other peoples screw ups
yr choice
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billl7
Dec 26, 2012, 6:19 PM
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milesenoell wrote: The one time I have actually stopped someone with a fireman's belay was with a BIG guy on a brand new and pretty skinny line so I opted to loop the end under my butt and sit into the loop for tension. While I've never really examined this approach for weaknesses it does seem to make it very intuitive, since any motions the person on the ground makes to get out of the way of the way results in tension to stop the fall.
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jcrew
Dec 26, 2012, 9:13 PM
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marc801 wrote: namoclimber wrote: Is this a common practice to not use double rope rap when available. In canyoneering, a double rope rap is almost never used except by the clueless. .
guess i'm clueless,......why the hell was he only on 1 wet strand of rope? why is it so cool to rap 1 strand in a canyon?
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billl7
Dec 26, 2012, 10:05 PM
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In the linked forum, he said they did a single-line rap so that the more experienced one (with the camera), could ascend the free line if his partner got stuck and needed help.
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billl7
Dec 26, 2012, 10:57 PM
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To look at how sensitive the french-prusik autoblock might be to number of wraps, I did some testing. I tried to be as close as practical (for me) to reproducing their rope and cord diameters:
* 9.2 mm Sterling Nano vs. their 9.0 mm Blue Water Canyon Line;
* 6 mm perlon accessory cord vs. their unknown dia cord although ratio of cord to rope looks about right for 6 mm in their images,
Edit: The scope of the testing was increased from that shown below. All current results are shown here.
To summarize: five wraps of the autoblock would stop a drop of a 34 pound weight (via bathroom scale). Four wraps would not stop the same drop, albeit with travel limited to about 2 feet. Each autoblock config was tried 5 times to check reproducability - results were reproducable. And for each drop I would lock off, push the autoblock down about an inch, and then let go.
Interestingly, both configs could hold the weight if the autoblock was pre-tensioned.
This was with 22 1/2 inch stretched-out loop (~45" circumference). loop girthed to leg loop behind buckle (Petzl Adjama), wrap towards load, clip leg loop rear-ward of the girth. It was probably a longer loop than Matt's and would require extending the rap device to avoid interference.
Can provide more details of the tests if folks are interested.
Bill L
(This post was edited by billl7 on Dec 27, 2012, 4:04 AM)
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patto
Dec 27, 2012, 12:54 AM
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jcrew wrote: guess i'm clueless,......why the hell was he only on 1 wet strand of rope? why is it so cool to rap 1 strand in a canyon?
A secondary benefit is that it makes rescues easier, particularly if the FIRST person needs rescuing from above.
That said it does seem that single rope raps in canyoning are used excessively. There certainly is some people other there prefering double rope raps.
I'm leaving tomorrow for an 8 day canyoning trip. I'm using a tube device, most of the others will be using a figure-8.
billl7 wrote: To look at how sensitive the french-prusik autoblock might be to number of wraps, I did some testing. I tried to be as close as practical (for me) to reproducing their rope and cord diameters:
Excellent! Great to see some testing! Also 6mm is likely a little too fat for 9mm rope.
Personally I do not like the reliance on the french-prusik aka the "autoblock knot". IF I am going to use a prusik for backup then I'll use a klemheist or a traditional prusik with the rap device extended.
I find this an absolutely reliable system. I don't normally use rappel backups but if I am I don't see the point in using any system that is not extremely reliable.
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wivanoff
Dec 27, 2012, 12:56 AM
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jcrew wrote: marc801 wrote: namoclimber wrote: Is this a common practice to not use double rope rap when available. In canyoneering, a double rope rap is almost never used except by the clueless. . guess i'm clueless,......why the hell was he only on 1 wet strand of rope? why is it so cool to rap 1 strand in a canyon?
It's not that it's cool
One reason is that there's less tangling. Imagine rappelling down a waterfall into a deep plunge pool with a big tangle of excess rope in it. Or tossing two ropes down a waterfall and having them get all tangled up before you start your rappel.
It's much better to lower one end of the rope to the correct length and block it so everyone rappels down that single strand. Once they get into the pool they only have a short length of rope to deal with and they can pull it through their rappel device and swim away. Last person down removes the safety, rappels single stand and either brings the rope bag down with him or tosses it off. Still less cluster than two long ends. AND less rope to pull down because you've set the rope length for the length of the rappel. Also allows for extra rope on top for rescue use if needed.
On longer rappels, you could use a full length of rope and a pull cord to save some bulk/weight. Once again, rappel on one strand and last person down takes care of the pull cord.
This is just one case. In another situation, you might decide to rap on a doubled line like we're used to in climbing.
But, I'm still not clear why you anyone would use a 70m rope AND a 70m pull cord payed out in buckets by the first person down for an 8m drop. Seems like you'd they'd have an awful lot of rope to pull down after rappelling.
Edit: spelling
(This post was edited by wivanoff on Dec 27, 2012, 2:11 PM)
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moose_droppings
Dec 27, 2012, 1:16 AM
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milesenoell wrote: The one time I have actually stopped someone with a fireman's belay was with a BIG guy on a brand new and pretty skinny line so I opted to loop the end under my butt and sit into the loop for tension.
Maybe Curt's foot belay would work in combination with the firemen's belay.
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billl7
Dec 27, 2012, 4:02 AM
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Tried the same setup as the original test with 5 mm Blue Water accessor cord (new, EN564). With same results. Decided to try shortening the loop to shorter stretched out lengths with results shown below (orig tests included).
Edit: * Pre-tensioning the french-prusik allowed it to hold the weight.
With the french prusik, length can matter.  I suspect the shorter lengths force the coils to stay more closely together and so to run in a more compact coil around the rope. This way, more of the cord can act as two fingers do pinching on directly opposite sides of the rope rather than two fingers on opposite sides of the rope but offset up and down the rope from each other.
With the aforementioned prusik & kleimheist, the hitch itself better governs its own compactness in dimension up and down the rope.
I haven't checked out how easily each different configuration can be tended during the rappel (i.e., ease of being pushed down the rope by hand). Might be pretty difficult, especially with the 13 inch loop of cord and four wraps.
Bill L
(This post was edited by billl7 on Dec 27, 2012, 4:39 AM)
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milesenoell
Dec 27, 2012, 6:36 AM
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moose_droppings wrote: milesenoell wrote: The one time I have actually stopped someone with a fireman's belay was with a BIG guy on a brand new and pretty skinny line so I opted to loop the end under my butt and sit into the loop for tension. Maybe Curt's foot belay would work in combination with the firemen's belay.
Classic!
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billl7
Dec 27, 2012, 4:27 PM
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milesenoell wrote: moose_droppings wrote: Maybe Curt's foot belay would work in combination with the firemen's belay. Classic!
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billl7
Dec 27, 2012, 5:18 PM
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After a bit more testing (details below), here are some summary points about using the french-prusik as an autoblock below the rap device:
a) The author of the linked forum contended that clipping forward or aft of the girth made the difference. True - changing the number of wraps by half-a-wrap can indeed make a difference.
b) The length of the loop of cord matters with the french prusik. It affects the compactness of the hitch and so affects ability to grip.
c) Others in this thread have stressed testing the exact config as being important. That is good advice. Variables that can make a significant difference include one-stranded versus two-stranded rappels. The significance of wet versus dry conditions was not tested.
d) In situ testing should not include pre-tensioning the french prusik as this can hide the actual effectiveness in some surprise falls (assuming a surprise fall is what one hopes to back up).
Bill L
P.S. A little more detail from further testing that supports some points stated above ...
After scrutinizing the clearest image of the autoblock in this thread and after a little trial and error, the config chosen to best approximate the accident was a 13" loop with ~3 wraps of 5mm cord with a locking biner that was about 3 3/4" in longest length (BD Positron Screwgate, outside measurement).
Clipping rear-ward of the girth passed the drop test. Clipping front-ward of the girth failed the drop test (removes half a wrap bringing the total to ~2 1/2 wraps). In both cases, pre-tensioning the autoblock held the weight.
Note that all my testing was done dry.
(This post was edited by billl7 on Dec 27, 2012, 5:34 PM)
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marc801
Dec 27, 2012, 5:46 PM
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wivanoff wrote: But, I'm still not clear why you anyone would use a 70m rope AND a 70m pull cord payed out in buckets by the first person down for an 8m drop. Seems like you'd they'd have an awful lot of rope to pull down after rappelling.
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jcrew
Dec 27, 2012, 9:22 PM
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wivanoff wrote: jcrew wrote: marc801 wrote: namoclimber wrote: Is this a common practice to not use double rope rap when available. In canyoneering, a double rope rap is almost never used except by the clueless. . guess i'm clueless,......why the hell was he only on 1 wet strand of rope? why is it so cool to rap 1 strand in a canyon? It's not that it's cool One reason is that there's less tangling. Imagine rappelling down a waterfall into a deep plunge pool with a big tangle of excess rope in it. Or tossing two ropes down a waterfall and having them get all tangled up before you start your rappel. It's much better to lower one end of the rope to the correct length and block it so everyone rappels down that single strand. Once they get into the pool they only have a short length of rope to deal with and they can pull it through their rappel device and swim away. Last person down removes the safety, rappels single stand and either brings the rope bag down with him or tosses it off. Still less cluster than two long ends. AND less rope to pull down because you've set the rope length for the length of the rappel. Also allows for extra rope on top for rescue use if needed.
o.k. copy that.....but this beta doesn't seem applicable to this situation. IMO, he would have had a lot more control if he'd threaded both ropes. the friction alone would have probably almost stopped him. it seems they were slavish to the technique, not understanding the reasons for the technique.
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billl7
Dec 27, 2012, 10:20 PM
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jcrew wrote: o.k. copy that.....but this beta doesn't seem applicable to this situation. IMO, he would have had a lot more control if he'd threaded both ropes. the friction alone would have probably almost stopped him. it seems they were slavish to the technique, not understanding the reasons for the technique.
It seems unlikely that rapping on two strands would have "almost stopped him", especially on so short of a rap. I find double 9's on a standard ATC to be 'fast' ... enough so that I'm usually either planning to use a different rap device or doubling up on the ATC's locker. Edit: Some of my lighter climbing partners think an ATC-rap on double 9's is okay but I generally don't hear them complaining of too much friction.
All that said, double strands may have helped with the autoblock engaging (not sure). And, even before that, perhaps he would have felt less pressed to just trust to the autoblock.
And I agree that the primary issue was losing control in the first place; thanks for re-emphasizing that in this thread. It would be wrong to assume the beta from the autoblock analysis addresses what is the primary issue.
Bill L
(This post was edited by billl7 on Dec 27, 2012, 10:27 PM)
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Syd
Dec 28, 2012, 3:29 AM
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billl7 wrote: Right. The explanation in that thread for why the autoblock didn't work was that the final clipping to the leg loop should be "at the block's girth" but was not. It was forward on the leg loop where it then "slid up [along the leg loop] and couldn't cinch". This guide teaches that clipping forward of the girth is fine. In David Fasulo's "Self-Rescue" book (1996 - it was recently revised), several illustrations show clipping rear-ward of the girth. Is it really that critical whether the biner is clipped forward, at, or rear-ward of the girth? Can an autoblock in this application really be that sensitive? Bill L
I've always used a normal French Prusik, that is, with the biner clipped into both ends of the cord, then the biner clipped anywhere to the leg loop. I don't attach the cord directly to the leg loop at shown. It seems to work well.
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healyje
Dec 28, 2012, 11:00 AM
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Rgold wrote: The one thing I disagree with is your statement that the accident has nothing to do with the failure of an autoblock. It is beyond contention that the autoblock failed, probably because it was set up too close to the rap device. If the autoblock had held, there would have been no incident at all. Of course he should never have let go of the brake strand like that to begin with, but once he made that potentially fatal error, the autoblock indeed failed to function.
I wasn't commenting on the autoblock failing or not, but was simply stating my opinion the presence or absence of an autoblock was irrelevant in this incident and, as marc801 is also saying, the direct cause of the accident was a lack of competence, skill, and judgment for the rappel at hand.
Personally, when I've used an autoblock I have never 'relied' on it to compensate for any aspect of my ability to manage a rappel. Any assumption an autoblock or any backup device can compensate for lack of skill, competence, or judgment is beyond erroneous, it's a disaster waiting to happen at any moment (and don't even get me started on the risks of rapping waterfalls for a good time).
As for use of a fireman's belay, it's a belay no different from any other belay and if you as a belayer can't competently manage and execute such belay then you shouldn't be doing it and probably shouldn't be belaying TRs or leads either. It's not as common a belay today as it was BITD, when it's use was fairly routine, but its effect is immediate and excellent for the purpose.
As to the effectiveness of autoblocks on skinny, wet, single ropes (let alone figure-8s) you damn well better tune it all out ahead of time and know what the hell you're dealing with. If I somehow became delusional enough to partake of this activity I'd only do it on a 10mm rope and an Anthron double-stop Descender.
(This post was edited by healyje on Dec 28, 2012, 6:56 PM)
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billl7
Dec 28, 2012, 4:07 PM
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An industrial analogy about backups to human operators ...
Powerful cranes often have mechanically triggered limit stops that are necessarily out of the human operator's eyesight. Without an upper limit stop, the full power of the hoist motor can be used to pull an empty hook into the crane structure, leading to catastrophic failure and so to injury or death of those below by falling crane parts.
A very common procedure after setting down a load is to stow an empty crane hook up and away from ongoing work. A crane operator could a) raise the empty hook until it hits the upper limit stop. Or a trained operator could b) stop raising the hook just before it hits the limit stop.
Unnecessary care-free activation of the last backup to failure is best left to settings outside of normal operations.
Bill L
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DFCLIMB
Jan 19, 2013, 2:43 AM
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It looks as though there were not enough wraps on the friction hitch (although it is hard to see for sure on the video). It is best to have the rappel device extended to better control the descent and to ensure the friction hitch does not touch or interfere with the rappel device.
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