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Chockstone Forum - Accidents & Injuries
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12:10:59 PM |
On 22/04/2010 evanbb wrote: >I do it off my harness sometimes too, mostly so I can sit on the edge when the anchor is a long way back. But, with some fiddling you can belay off the anchor from a long way away. I'm confused a bit here Evan, if you're sitting on the edge you've already extended the anchor to the edge, haven't you? In the same situation, I'd usually just use a couple of figure eights in the rope to extend them anchor to the edge, clip myself in to that and belay off it too. Is that the kind of thing you mean? |
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12:24:04 PM |
Autoblock device (eg reverso) attached to anchor. Climber extended to edge holding brake end of rope to take in | |||||
12:40:57 PM |
On 22/04/2010 cruze wrote: >Autoblock device (eg reverso) attached to anchor. Climber extended to edge >holding brake end of rope to take in This is exactly what I used to do and it was magic apart from the one time my second wanted to try a move again after not being completely satisfied with her first attempt - with the belay about 1m back from me it was difficult to pay out rope as the reverso locks. So now i extend the anchor so the device is easily reachable and i am in the best position to manage everythng. The reverso is great for this as once the leader reaches you its really easy to take off the anchor and clip to you loop and the seconder is now the leader boom ! |
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1:04:30 PM |
On 22/04/2010 bluey wrote: >To the tech heads out there, I had thought that a true factor 2 fall (i.e. >plummet directly past the anchor without being slowed by a popping piece >of gear) means you should retire the rope afterwards.....is that right? >or have I just made that up??? I certainly would be cutting my rope for a true factor 2 fall. Given the nature of factor 2s this is inevitably only a small section. I've only taken one big fall on my rope and that was probably only a factor 0.3-0.5 fall. But I can still feel a vague soft spot in the rope after that fall! This brings up the point that the leader probably should have changed ends before leading the pitch again. On 22/04/2010 stuart h wrote: >Perhaps the single biggest danger of factor 2 falls, especially in Victoria >where we tend to have excellent protection available to build bombproof >anchors, is that the impact force on the belayer and the belay hand may >be so large as to cause enough movement for the belayer to lose control. Excellent points all round Stu. And I think the above is the most important aspect. As fun as it is to discuss the physics, the most likely failure point normally would be the belayer. That said: On 22/04/2010 stuart h wrote: >Someone with a greater knowledge of and enthusiasm for physics might be >able to explain the difference between tension and impact force, but I >think two things are important:..... I would claim that I have a greater enthusiasm, i light of that....... On 22/04/2010 stuart h wrote: >coupled with John Long’s revelations about the relative >ineffectiveness of most ‘equalisation’ strategies, highlights that the >multiple components in an anchor are really generally functioning for redundancy >rather than load sharing. There is so much very wrong about John Longs 'revelations' on two different levels. One, even 'poor' equalisation can still reduce the peak in a 3 piece anchor by 30-50%. This is certainly not to be sneezed at. Two, and most importantly, his conclusions supposably dispelling the shock loading are fundamentally flawed. This papershows testing that clearly shows than anchor extension can cause impact forces in an equalette to be around 5x higher than the mass at the anchor. With tech cord equalette it would even be greater. In some tests peak loads reach 18kN!! The flaw in john's testing was that he had no mass at the anchor. In the case of a true factor two fall OR for a hanging belay then there is a mass at the anchor, the belayer. That said the above testing over represents the effect of impact of anchor extension by using a 260kg mass clearly heavier than most anchors. The upshot of all this is a cordalette is fine. Back on topic the issue with clipping your highest piece on the anchor is that if a fall does occur then you are now loading your other two pieces with: upwards force and a higher 'shock loading' force of the belayers mass. This is compounding the fact that the higher piece is receiving 1.7 times the load due to the pulley effect. Furthermore the belayer has a good chance of being pulled into the top piece carabiner if the other pieces aren't ultra short. When this occurs I'm not sure that catching the upwards pull is necessarily easier than catching a downwards factor 2. All that said catching a downwards factor 2 is something I'm not in a hurry to volunteer for. Neither option is clearly the better of two evils. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ If you are really worried about a factor 2 fall then hang the belayer 5m below the anchor. Suddenly any possibility of a high factor fall dissapears. Furthermore you should have a bomber first piece of the anchor. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
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1:15:15 PM |
My 2 cents. If doing a multi pitch route when I come to a belay i will: Build the belay Pull in rope. Put second on belay off my harness. Run rope from myself up through a high piece/s of the belay and back down to the second. This makes belaying the second easy and you are set up for belaying the second if they are leading through. |
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1:24:11 PM |
It wasn't anyone here who suggested it. It was other friends and I didn't agree with them. But i was trying to work out why belaying of your harness is better than off the anchor. On 22/04/2010 patto wrote: >It sounds like you existing method is fine. I'm a little confused about >how you can provide a effective lead belay if you are belaying directly >off the anchor. I might be mistaken but I think you are getting something >mixed up here. I don't think any body here is suggesting anybody give >a lead belay from anywhere but the harness. |
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1:31:00 PM |
On 22/04/2010 ajfclark wrote: >I'm confused a bit here Evan, if you're sitting on the edge you've already >extended the anchor to the edge, haven't you? In the same situation, I'd >usually just use a couple of figure eights in the rope to extend them anchor >to the edge, clip myself in to that and belay off it too. Is that the >kind of thing you mean? Yeah, that's pretty much it. In the scenario above I would make an anchor, say 4m away from the edge, just a standard 3 piece trad anchor. I then put my lead rope through the main point and if necessary sort of abseil down to the point I want to belay from. I then tie a figure8 on a bite (bight?) on the upcoming rope and clip that so that I'm anchored. Almost always now that I have a BD Guide, I then tie a second F8 below my knot and clip the belay device into that and give them a top belay. Even safer on double ropes as my rope and the belay rope can be seperated. Better? EDIT: I'd originally mentioned a figure 9. I'm not supposed to tell anyone about that yet. |
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1:46:25 PM |
Also from memory doesn't lamplighter traverse on the second pitch? So this wouldn't be a factor 2 fall in that case would it? Wouldn't you have to be going straight up for it to be a factor 2 fall? | |||||
2:02:45 PM |
On 22/04/2010 widewetandslippery wrote: >My 2 cents. If doing a multi pitch route when I come to a belay i will: > >Build the belay > >Pull in rope. > >Put second on belay off my harness. > >Run rope from myself up through a high piece/s of the belay and back down >to the second. > >This makes belaying the second easy and you are set up for belaying the >second if they are leading through. If I understand correctly then that means the rope goes from your belay device, through the top piece of gear and then to the second. Personally I would avoid this because if the second falls, the load will all be on that top piece of gear and it will be doubled (due to 2 load-bearing strands of rope). If it pops you're in a bad situation - you'll have one less piece of gear in your anchor which could result in shock loading due to extension (depending on how you set it up) and will almost definitely result in your anchor being loaded in a different direction than you expected. |
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2:03:33 PM |
On 22/04/2010 evanbb wrote: >Better? Yes. Sounds like we're very much on the same page, with the same general setup. You're correct that it's bight too. |
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7:00:27 PM |
On 22/04/2010 gordoste wrote: >On 22/04/2010 widewetandslippery wrote: >>Put second on belay off my harness. >If I understand correctly then that means the rope goes from your belay >device, through the top piece of gear and then to the second. and will almost definitely result in your >anchor being loaded in a different direction than you expected. What WWS is talking about is belaying from your harness - as opposed to what the previous discussion involved, belaying from the Anchor using an ATC Guide or Reverso - in WWS case he's created a mini Top-Rope like in a gym, as long as the rope is reasonably tight there shouldn't be any strain on the anchor. |
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7:08:55 PM |
>If I understand correctly then that means the rope goes from your belay >device, through the top piece of gear and then to the second. Personally >I would avoid this because if the second falls, the load will all be on >that top piece of gear and it will be doubled (due to 2 load-bearing strands >of rope). If it pops you're in a bad situation - you'll have one less piece >of gear in your anchor which could result in shock loading due to extension >(depending on how you set it up) and will almost definitely result in your >anchor being loaded in a different direction than you expected. If you are belaying a 2nd properly from above, there should not be enough slack rope out to cause any serious shock to a belay. If they have to rest the load is dispersed by the anchor and not the harnes of the belayer. I made the mistake of belaying directly off my harness once, when my 2nd rested i was in a very uncomfortable position pinned to the rock, and could not offer any assistance. I will always belay through a high point when I can. |
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7:25:02 PM |
On 21/04/2010 Olbert wrote: > >> >Do you really want to say this to a struggling beginner leader? My friends >have been in a situation where a climber has made a poor decision and as >a result completely lost there head. It was commented by the leader afterwards >that the fact that the belayer stayed calm and confident (or so the leader >thinks) it really helped him keep him in it. > As the leader in this situation, I have to agree completly. It was my first trad lead close or at my limit in 3 months after spending all summer on real mountains in NZ, and quickly realised how less solid i had become (yes ollbert, that IS possible :P). Poor decision was using a rubbish cam, thinking i had a good enough stance to place it properly. Cam went in sideways, my brain exploded and it was all thanks to dave staying dead calm and cool despite my tears and shakes and screaming till i got in a bomber cam onto which i slumped, much relived. The nature of the pitch meant that a fall would have been pretty horrible for both of us, and afterwards david admited that he was packin it too. Climbers and belayers must both realize that trad, particually multi pitch, is the ULTIMATE team sport, and mistakes made by one affect the other, potentially fatally, and that communication must resect such level of commitment. As for fixed gear, same as in the mountains - Clip ANYTHING, trust nothing. |
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9:37:36 PM |
Man, I was really trying to stay away from technogeek threads....but the chance to hang shit on evan is too good to miss On 20/04/2010 evanbb wrote: >You said your leader slumped onto a cam, which popped, before she fell. >For a Textbook Factor 2 the rope above the belay should essentially be >dead vertical with nothing in between, even if it is a terrible cam. This, >however hopeless, will diminish the fall factor. What you probably experienced >was more like a factor 1.9. Imagine if it was worse! > Say Ev, did you learn those mad figuring skils in enginears skool?! Fark, I hope I never have to drive over one of your bridges!! Lets say mass of svelt female climber = 50kg Fall = 4m Cam slides at 50kg = 500N Cam pops after sliding 5cm = 0.05m Energy from falling = mgh = 50x10x4 = 2000J work needed to rip cam = F x D = 500 x .05 = 25J So, that bodyweight cam placement absorbed only 1.5% of the energy of a pissy 4m fall.... so your claims of significant reduction in fall factor are, in fact, arsetalk!......maybe you should consider a career change? Anyway, all this crap about factor 2 shit....everyone knows that when you fall off lamplighter and hit the ledge, the energy is dispersed in ankles......and belayers thighs apparently....safe as houses! |
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4:46:02 AM |
I think he was more concerned with the extra rope running from the harness up to the rubbish cam when slumped on. For a true factor two - falling distance = 2x length of rope, and by having a small amount of rope, say 30cm, paid out between harness and cam a mathematical factor 2 is impossible - but it is still a fall I never want to have to take. | |||||
6:18:16 AM |
On 22/04/2010 One Day Hero wrote: >Man, I was really trying to stay away from technogeek threads....but the >chance to hang shit on evan is too good to miss And there's nothing I like more than someone arrogantly correcting me, incorrectly. Fall Factors have nothing to do with energy dissapation and everything to do with geometry. |
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5:18:43 PM |
On 23/04/2010 evanbb wrote: >And there's nothing I like more than someone arrogantly correcting me, >incorrectly. > >Fall Factors have nothing to do with energy dissapation and everything >to do with geometry. Wrong..........fall factors have everything to do with energy dissipation. You take potential energy, turn it into kinetic energy, then absorb and dissipate all the energy by stretching a rope! No calculation shortcuts can change the physics, they can however make it easy for layfolk to work stuff out in simple situations. This is not a simple situation, fall factor thinking can't solve this problem, go back to energy to work out whats happening then reconvert to fall factor so the masses can (semi) understand! |
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6:15:49 PM |
On 23/04/2010 One day Hero wrote: >Wrong..........fall factors have everything to do with energy dissipation. >You take potential energy, turn it into kinetic energy, then absorb and >dissipate all the energy by stretching a rope! No calculation shortcuts >can change the physics, they can however make it easy for layfolk to work >stuff out in simple situations. This is not a simple situation, fall factor >thinking can't solve this problem, go back to energy to work out whats >happening then reconvert to fall factor so the masses can (semi) understand! I think the usual definition of fall factor is the length of the fall divided by the amount of rope in the system when it becomes taught (potential uncertainty here). This definition does not explicitly incorporate energy. It is mostly about geometry of the setup (though can be influenced by other things eg belayer taking/giving slack...potentially leading to fall factors greater than 2!). If you change the definition to explicitly incorporate energy then you are talking about something else. As I understand it fall factor is a measure of the severity of the fall on the rope and less directly on other components of the system. It is only one measure and does not give a complete understanding of the system. As you say energy considerations are important but very difficult to assess. Fall factor is easy to assess especially while climbing and I guess a rule of thumb of sorts. |
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6:16:23 PM |
What I mean is the official fall factor measurement is purely a function of distance of fall/length of rope absorbing the fall. I do not dispute that putting gear in will make the fall less bad, and of course it will dissipate some energy. But, by definition, a pure factor 2 fall can only happen when a leader is directly above the belay point and falls with no gear in. In the example the leader rests, however briefly, on a cam. It might even have been a factor 1.98, but, it definitely wasn't a 2. I agree with everything else you say, of course the energy equations change and yes, falling still converts potential energy into kinetic. My original post that raised it was pure pedantry and in no way useful or important. All this is academic, the only thing that is important here is if the leader had put more gear in the fall wouldn't have been as bad. |
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3:21:19 PM |
On 23/04/2010 evanbb wrote: > >In the example the leader rests, however briefly, on a cam. It might even >have been a factor 1.98, but, it definitely wasn't a 2. What I was getting at is that factor 1.98 = factor 2 for any purposes I can think of > My original >post that raised it was pure pedantry and in no way useful or important. Mine too, I was trying to out pedant you :) >All this is academic, the only thing that is important here is if the leader >had put more gear in the fall wouldn't have been as bad. .....more GOOD gear! Extra cams in slippery downward flares would have had a similar negligable effect on removing energy from the fall (outpedanted!) |
| There are 64 messages in this topic. |
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