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tj2870
Apr 7, 2013, 1:11 AM
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A very knowledgeable guide brought up an issue with this device, and I'd like other opinions. Consider having a rope 9.5mm or less. Set up an autoblock to belay your follower on a trad climb. Now consider a great load (fall) from the climber's strand while the belayer has the brake strand pushed forward a bit inside the ATC (pulling the excess). The ropes cross each other and get lodged on opposite ends of the ATC interior (follower strand on the teeth). In order to fix it under load, you'll need to leverage the ATC upward to pop the strands back into place. This is a very dangerous situation, and while it may not happen 999/1000 times, it's worth keeping in the back of your mind.
It's not difficult to create this scenario on your own, if you'd like to test it out. Obviously you can tie a safety knot of your choosing to prevent this from happening, but only if you are a thoughtful climber. What do you guys think?
I can really imagine this happening when climbing in 3s on thin double ropes.
(This post was edited by tj2870 on Apr 7, 2013, 2:35 AM)
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jt512
Apr 7, 2013, 1:40 AM
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tj2870 wrote: A very knowledgeable guide brought up an issue with this device, and I'd like other opinions. Consider having a rope 9.5mm or less. Set up an autoblock to belay your follower on a trad climb. Now consider a great load (fall) from the climber's strand while the belayer has the brake strand pushed forward a bit inside the ATC (pulling the excess). The ropes cross each other and get lodged on opposite ends of the ATC interior (follower strand on the teeth). In order to fix it under load, you'll need to leverage the ATC upward to pop the strands back into place. This is a very dangerous situation, and while it may not happen 999/1000 times, it's worth keeping in the back of your mind. It's not difficult to create this scenario on your own, if you'd like to test it out. Obviously you can tie a safety knot of your choosing to prevent this from happening, but only if you are a thoughtful climber. What do you guys think? I can really imagine this happening when climbing in 3s on thin double ropes.
There's pretty much no good reason to belay in autoblock mode, and some good reasons not to, including the one you mention. This subject has been debated more than once. Did you try doing a forum search before posting your question?
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acorneau
Apr 7, 2013, 1:41 AM
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[Edit to remove quote by Jay]
Umm... Are you talking about an ATC Guide in guide mode, perhaps?
(This post was edited by acorneau on Apr 7, 2013, 1:42 AM)
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tj2870
Apr 7, 2013, 1:46 AM
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I meant autolock, sorry. Yes, in guide mode.
Yes I did a search here after extensive google searching. Did I dig into every thread involving an ATC discussion? No. I'll look a bit harder now, though, since you mention that it's been discussed before.
Edit: Still looking. I see discussion about not relying on the brake hand to be a 100% effective autolock (or autoblock as many people -have- said), but not this exact issue. I'll keep looking.
(This post was edited by tj2870 on Apr 7, 2013, 1:55 AM)
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tj2870
Apr 7, 2013, 2:03 AM
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Alright. I've looked in many threads at this point and haven't seen anything. Either it's late and I suck, or it's in a thread that isn't readily obvious for this type of discussion.
Also, I've noticed many other climbers in threads calling it autoblock mode when referring to the BD ATC guide. I don't see where I went wrong originally, Acorneau, especially considering the context of the original post.
Further edit: Saying there's no good reason to belay a follower in this mode makes it scary, because isn't the piece designed to do so? It's scary.
(This post was edited by tj2870 on Apr 7, 2013, 2:08 AM)
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jt512
Apr 7, 2013, 2:26 AM
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tj2870 wrote: Alright. I've looked in many threads at this point and haven't seen anything. Either it's late and I suck, or it's in a thread that isn't readily obvious for this type of discussion.
Here's one thread: http://www.rockclimbing.com/..._reply;so=ASC;mh=25;
In reply to: Also, I've noticed many other climbers in threads calling it autoblock mode when referring to the BD ATC guide. I don't see where I went wrong originally, Acorneau, especially considering the context of the original post.
You called it a "Black Diamond ATC," which is this device:
In reply to: Further edit: Saying there's no good reason to belay a follower in this mode makes it scary, because isn't the piece designed to do so? It's scary.
I'm not sure I understand that question, but, yes, the device is designed to optionally be used in an autoblocking mode. That doesn't mean that there is any good reason to use it in that mode. It's difficult to let out slack if your partner needs, it can jam in a fall, and unjamming it is difficult and potentially dangerous. And what's the benefit? That you can take your hands off the rope? You shouldn't be doing that anyway.
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tj2870
Apr 7, 2013, 2:45 AM
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Ah, I understand the confusion I caused then (sorry Acorn). I forgot that silly ATC existed, to be honest. Thanks for pointing it out.
I checked the thread. It doesn't consider the strands crossing each other with thin ropes, but the leverage issue is what matters most I suppose. With the strands of rope crossed, there's simply no way you can react in time to stop your second from decking or coming very close to it. I know plenty of people that belay their second using the guide ATC in autoblock mode. I have to discuss this with them because they've been belaying me this way for 2 years now...
I only used the autoblock mode because I, mistakenly, thought it was as close to fool-proof as you could get. Friends of mine (long-time climbers) have been doing so for many years. Clearly I have to be more skeptical.
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redlude97
Apr 7, 2013, 2:49 AM
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Its called guide mode for a reason. If you don't know what you are doing you have no business using it.
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tj2870
Apr 7, 2013, 3:01 AM
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redlude97 wrote: Its called guide mode for a reason. If you don't know what you are doing you have no business using it.
I hope you feel better for a useless contribution. I know how to use the device just fine, but anticipating all of the problems that can arise doesn't come as easy to some people as it may come to you.
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redlude97
Apr 7, 2013, 4:48 AM
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tj2870 wrote: redlude97 wrote: Its called guide mode for a reason. If you don't know what you are doing you have no business using it. I hope you feel better for a useless contribution. I know how to use the device just fine, but anticipating all of the problems that can arise doesn't come as easy to some people as it may come to you.
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billl7
Apr 7, 2013, 5:49 AM
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Never thought of it. But it does make sense this can happen.
At the same time, if one is using it in guide mode then it should already be understood how to safely release it.
Bill L
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notapplicable
Apr 7, 2013, 7:33 AM
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tj2870 wrote: I only used the autoblock mode because I, mistakenly, thought it was as close to fool-proof as you could get. Friends of mine (long-time climbers) have been doing so for many years. Clearly I have to be more skeptical.
I'd never thought of the rope strands crossing in that way. That is sketchy. Thanks for posting and I think you're right to be skeptical of the device. Of both it's supposed benefits and it's reputation for being foolproof.
IMO, If you look up the word 'superfluous' in the dictionary, you should see a picture of a belay device being used in "guide mode". The prevalence of the notion that they are "as close to foolproof as you [can] get" probably calls for a mention under 'dangerous' as well.
As I'm sure you noticed though, you will find several threads on here with people arguing for and against using devices in guide mode. It sounds like you're doing the right thing. Educate yourself and decide what makes sense for you.
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bearbreeder
Apr 7, 2013, 8:45 AM
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nothing is "foolproof" ... not belaying off the harness, not with a redirect, etc ...
but a properly used autoblock in a seconding scenario is pretty damn unlikely to fail ... thousands use em every day, every climbing season ... and you dont hear off too many people getting dropped off em, generally someone brings up the accident of the misrigged ATC guide of someone lowering ... user error
i use my alpine smart, atc guide and till a partner dropped it the reverso for thousands of pitches, bringing up one or two followers on ropes from 8-10.5mm
there are tons of better climbers and guides who use it much more than me for much longer on everything from humid jungles to the frozen arctic ... on screaming newbies they need to drag up
this has all been discussed before and argued to death
http://www.mountainproject.com/...c-guide/106838345__1
http://willgadd.com/...her-winter-thoughts/
http://kellycordes.wordpress.com/...locking-belay-plate/
the simple fact of the matter is that barring idiot who doesnt know how to use it properly ... you wont die from the autoblock
you MAY however die from people who pretend to know how to use it, especially if they learn off the intrawebs ... i was almost killed by one ...
is it the autoblocks fault? ... nope .. no more than someone being dropped on a munter is the munters fault ...
i did a run up an easy 6 pitcher monday using the deadly autobloc ... its a wonder im still alive ...
as to "superflous" ... i have one simple word on multi ... ROCKFALL
(This post was edited by bearbreeder on Apr 7, 2013, 8:48 AM)
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moose_droppings
Apr 8, 2013, 2:12 AM
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Looks like fun route, by why are there so many loose rocks getting knocked off by experienced climbers on the most popular mutipitch route (heavily travelled) in the Canadian Rockies?
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bearbreeder
Apr 8, 2013, 2:57 AM
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moose_droppings wrote: Looks like fun route, by why are there so many loose rocks getting knocked off by experienced climbers on the most popular mutipitch route (heavily travelled) in the Canadian Rockies?
if youve climbed it youll find out
the 1 hour hike up the scree field burns into your mind about how serious rockfall is an issue ... if it doesnt you need to have yr head checked
every ledge is littered with smaller broken off rocks ... if you look at the bottom left of the photo i posted, youll see rocks just lying on a small ledge ... every ledge had those rocks, bigger ones had more ...
theres loose rocks everywhere out there ... even at the most popular g-bang crag (grassi) youll usually see fists sized rocks come down all the time
we were almost killed at a place called heart creek ... on a popular wall the climber stepped on a hold and the entire thing broke away ... if we werent under an overhang we be killed and the climber i was belaying would be dead as well if they werent on a smart in that case
theres only so much you can control as the party on top .. you dont throw rocks down and do your best to avoid loose rock, but footholds break and the rope dislodges rocks as well
if there is a party on a multi route above you, its often a wise idea to just walk away and do a different route ... the guidebook indicates NOT to rap certain routes as it greatly increases the risk for other parties
in the canadian rockies, if you know theres a party above you and you decide to climb under em ... you take your chances
(This post was edited by bearbreeder on Apr 8, 2013, 3:25 AM)
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shockabuku
Apr 8, 2013, 3:02 AM
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bearbreeder wrote: notapplicable wrote: So you also carry a grigri to belay when your partner is leading? You know, just in case of rockfall. in the canadian rockies ... HELL YES ... or the alpine smart i currently use we almost got killed at a popular crag last year when a 50 lb rock broke off and landed a few feet away from us heres the most popular easy long multiroute in the canadian rockies ... notice the gray scree field at the bottom ... all those rocks from from somewhere ... and it aint heaven the party you see under us almost got hit by several rocks we inadvertently knocked off ... there are rocks lying everywhere on the route, and the limestone breaks off all the time ... i broke off a foothold on that particular run [image]http://i47.tinypic.com/2n80j82.jpg [/image] there is a "religious" hatred of autoblock, gri gris and many other such things by certain RCers ... get hit in the hand by a loose rock ... which i was 2 weeks ago (which was thankfully small) ... or even worse the head ... and if you dont sing a different tune, yr just a RCer zealot  between some RCer on the intrawebs sprouting about the "superfluousness" of autoblock, which you wont die from if everyone knows what they are doing ... and the REAL possibility of rockfall (or dropped gear by newbs on those moderate multis) which i see often enough ... i know which one id pick ...
You is a poster child RCer.
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rgold
Apr 8, 2013, 3:14 AM
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moose_droppings wrote: ...why are there so many loose rocks getting knocked off by experienced climbers on the most popular mutipitch route (heavily travelled) in the Canadian Rockies?
I've pretty much gone over to the dark side and use the Alpine Up, which is an assisted locker like the Smart that is better for half ropes. But I have other reasons, that don't involve rockfall, 'cause here's the thing: if you are the leader and you are falling and the belayer is unconscious, then autolocking is a very good thing. But if you are the leader and you aren't falling and the belayer is unsconscious, then autolocking could be a nightmare.
At the other end of the rope, an autolocker as an upper belay seems like a good idea for rockfall situations (much as I hate the upper belays I get from most of the users of autolocking devices). The only potential issue is that there seem to be a lot of users who just plain don't know how to release the device and lower safely, so I'd be especially wary about climbing with someone unless I had some good knowledge about their skills in this area.
The situation mentioned by the OP, in which the strands exchange places under a high load and so at least partially disable braking, has been produced in test conditions with thin ropes and dropped weights. I haven't heard of it happening to anyone in the field.
(This post was edited by rgold on Apr 8, 2013, 3:23 AM)
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moose_droppings
Apr 8, 2013, 10:39 AM
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I understand that and we have some awfully crumbly limestone here too. Just seems like several pieces coming off from just one team on one ascent is a little excessive and would warrant a good cleaning once in a while, being it's such a popular route with so many teams on it on a daily basis.
Tough old birds those Canadians.
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verticon
Apr 8, 2013, 11:20 AM
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This is what Jim Titt wrote about this issue in a similar thread on Mountain Project:
"As it happens there was a thread on another forum about using guide plates for roped soloing and I went off and pull tested a few to see what happened under load:-
First Fail Mode:
The trapped rope escapes sideways from under the tensioned rope and gets trapped between the tensioned rope and the side of the slot.This is very difficult to free off and you have to dismantle everything and twist the locking krab brutally to release the rope. Take your Prusiks.
Second fail mode:
Apply yet more load and the trapped rope where it crosses the tensioned rope goes down through the slot with a bang. At this point the holding power drops off considerably but not catastrophically, though pretty near!
Easy to release, just unclip the krab when unweighted. Still need to take your Prusiks!
ATC Guide. 10.2 Mammut, used, non-treated. First fail mode 4.8kN. No second fail mode, rope sheath cut at ca 9kN.
ATC Guide. 9mm Edelrid, used, non treated. First fail mode 2.96kN. Max fail load 5.58kN. Residual load 1.6kN
ATC Guide. 8.2mm Edelrid, new,treated. First fail mode 2.05kN. Max fail load 4.06kN. Residual load 1.2kN
Reversoł. 10.2 Mammut, used, non treated. First fail mode 3.68kN. No second fail mode. Rope sheath cut ca 9kN
Reversoł. 9mm Edelrid, used, non treated. First fail mode 2.25kN. Max fail load 3.60kN. Residual load 0.9kN
Reversoł. 8.2mm Edelrid, new,treated. First fail mode 1.6kN. Max fail load 2.38kN. Residual load 0.7kN
All with Petzl Attache 12mm round profile karabiner.
Not my idea of a reliable roped-solo device!
--------------------------------
The first failure is both strands are crossing inside the device and it jams up solid, you hear a sharp bang as this happens (we though something had broken). Then the crossing point of the ropes is forced out of the bottom of the plate and the original rope positions is reversed with a twist at the karabiner.
With thicker ropes as the crossing point starts to come out below the plate the rope is forced onto the underneath of the sides of the plate and core-shots so it doesn´t really ever reverse completely but shreds itself instead.
You can get a good idea of what happens by using a thinnish (6mm or so)cord and bouncing on it.
-----------------------------------
The numbers are low. With the 8.2mm rope a bit of flailing trying to get my foot in a foot loop was enough to dump me on the ground. However to be fair Petzl warn against using the Reversoł in guide mode on a single strand of this diameter. I have no info on what BD recommend.
The speed, rope length and energy have no bearing on the force required to cause failure.
The lock up is virtually instantaneous and slip negligable until failure."
I guess it answers your questions.
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sandstone
Apr 8, 2013, 5:59 PM
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jt512 wrote: ...There's pretty much no good reason to belay in autoblock mode...
That statement is dead on the mark, in the right context.
In the context of long climbs on short winter days (think long ice/alpine climbs), autoblock mode is extremely useful. The leader can belay up a second, or two seconds simultaneously, while at the same time snacking and hydrating, getting ready to lead the next pitch.
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curt
Apr 8, 2013, 10:25 PM
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sandstone wrote: ...In the context of long climbs on short winter days (think long ice/alpine climbs), autoblock mode is extremely useful. The leader can belay up a second, or two seconds simultaneously, while at the same time snacking and hydrating, getting ready to lead the next pitch.
Remind me to never let you belay me.
Curt
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