glen Posted July 1, 2002 Posted July 1, 2002 I was perusing supertopo and came across the linked thread on a recent fatal climbing accident in Zion. Presumably, the accident occured as a result of a figure 8 rolling over itself (ie a loop of the knot folding up towards the tails) causing total knot and system failure. The climbers were not exhausted and were being careful. Reading the thread made me think about all of the ways I've seen people tie of double rope rappels, the amount of razzing I've recieved for putting 18" tails on knots and making sure they are well dressed, and the overall casual attitude that I've seen many climbers take towards rappels and belaying. The natural inclination is to become casual about things we are comfortable with. That's fine. That characteristic of adaptation allows us to move on and devote our mental energies towards keeping a cool head on long runouts and difficult terrain. On the other hand, it is also good to make sure that we occasionally recheck ourselves to be diligent about checking our knots and belaying technique. To me, safely casual means that doing it right is second nature, not trusting that you will be able to catch a fall with a single finger holding the breaking end of the rope. Sorry this turned into a bit of an editorial. I'll step away from the soap box out there. Climb safe. Climb hard. Here's a link to the thread: Accident in Zion Quote
iain Posted July 1, 2002 Posted July 1, 2002 I think this accident (euro death knot, etc) was discussed here a short while back. Don't remember the topic name for you, sorry... Quote
Dennis_Harmon Posted July 2, 2002 Posted July 2, 2002 Mr. Granitologist/Glen, With all due respects, Sir, I would submit to you that climbing is inherently dangerous, or should be, and that more climbers have probably died on abseil than by any other means. There exits no tidy answer to your question... as we've lost more of the very best of our own in the same scenarios. That to say, and this may mean a whit, we need be especially careful on the descent when we're most tired, the light is failing, ice conditions are worsening, when we are under the most time pressure... and most at risk of screwing up. Dennis Quote
JayB Posted July 2, 2002 Posted July 2, 2002 More on the same topic here... http://www.cascadeclimbers.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=1;t=002425 Quote
glen Posted July 2, 2002 Author Posted July 2, 2002 Dennis, Sir: of course climbing is dangerous. To ignore that simple fact is dangerous in itself. My point is simply that a lot of people are just plain sloppy when it comes to belaying, etc. There have been a number of threads on this page talking (often spraying ) about how to talk to sloppy people and suggest that they belay differently, etc. That was not the point. I was simply reflecting on the way I've seen people behave and the difference between being casual and belaying correctly and being sloppy. In light of risk mitigation (climbers spend a lot of time and money mitigating risk), I would simply ask this one, simple question: why increase the risk by being sloppy? It is obvious that we need to be more focussed when light is failing, ice is bad, etc, but that doesn't mean that we should be sloppy when conditions aren't bad. Of course what is considered sloppy and dangerous to one is quite bomber to another. Just remember the long thread about hip belaying on rock routes a while ago. I think we would all agree that taking your hand off the brake rope often while the other person is leading is not the best approach. There is certainly gray area. Just make sure it works and keep an open mind when you see something new or someone makes a suggestion. They may totally wrong and out in let field (hell, that might be me right now), but then again they might be right too. Quote
Dru Posted July 2, 2002 Posted July 2, 2002 ya the moral of the story is, dont tie a fig-8, tie an overhand, if you wanna use the euro death knot, cause the fig-8 can invert and become a literal death knot. duh. Quote
genepires Posted July 2, 2002 Posted July 2, 2002 why do you think a figure 8 knot is more dangerous than a overhand knot? I assume that figure 8 knot discussed is like a euro death knot but made with a fig. 8 instead of a overhand. Quote
Lambone Posted July 2, 2002 Posted July 2, 2002 quote: Originally posted by glen: I think we would all agree that taking your hand off the brake rope often while the other person is leading is not the best approach. There is certainly gray area. Gri-gri's rule... Smoke a cigarrete, take a shot of whisky, pound another jolly rancher, read a book, change the tape, and perhaps take a shit...all while your bro is strung out on cam hooks above fixed mank and a few brassies with one two cam Alien just above the belay... damn I love aid climbing. Quote
Lambone Posted July 2, 2002 Posted July 2, 2002 quote: Originally posted by genepires: why do you think a figure 8 knot is more dangerous than a overhand knot? I assume that figure 8 knot discussed is like a euro death knot but made with a fig. 8 instead of a overhand. It is easier for the knot to sort of "unfold" on itself when pulled like apart, as on rappel. It kindof reverses and unrolls. Two people playing tug of war can cause this to occur. The overhand does not tend to "unroll" quite as badly. The AMGA instructor that I took a course with said its quite a bit stronger than the 8 in that respect. Also of note: Be carefull using a reverso to do a single rope "one strand" rappel, especialy if it is a skinny chord. There isn't much friction there. My buddy had to wrap the rope around his leg and hold the rope with two gloved hands o remain in control on a 200ft rap with one 9.8 mil rope.Just something to watch out for. Quote
forrest_m Posted July 3, 2002 Posted July 3, 2002 to expand on what lambone said... unlike a double fishermans, which will cause the rope to break before the knot slips, the method of failure for both flavors of EDK knots is called "capsizing" or sometimes "inverting". , as lambone mentioned the knot crawls over itself, reappearing reversed further towards the ends of the ropes. the figure 8 uses a lot more rope than the overhand to tie, so every time it capsizes, it uses up a bigger piece of the tail; therefore, fewer "capsizing" events are required before the knot walks itself off the end of the rope. the force required to capsize the knot is relatively fixed for any given combination of knot and rope diameter; force builds up in the rope until it capsizes, which usually disperses some force; if the overload is constant, the capsizing events will follow each other in quick succession (not good). in addition, the initial force required to capsize the knot is less with a figure 8. i'm not certain why that is, but i think it has something to do with the fact that the knot itself is bigger, therefore is acts kind of like a lever arm to force the strands over itself? (just speculation here). there is a good discussion and - lord have mercy - test results posted here: http://www.tradgirl.com/climbing_faq/advanced.htm#rappel Quote
HeadSpace Posted July 3, 2002 Posted July 3, 2002 quote: Be carefull using a reverso to do a single rope "one strand" rappel, especialy if it is a skinny chord. There isn't much friction there. My buddy had to wrap the rope around his leg and hold the rope with two gloved hands o remain in control on a 200ft rap with one 9.8 mil rope.Just something to watch out for. Use multiple locking biners. It increases the braking power dramaticly. Quote
genepires Posted July 3, 2002 Posted July 3, 2002 All this talk of the ropes folding over and from my experience, only once did I have one EDK that looked even partially inverted. (and I have had plenty of rappels with my 200 lb ass) Has any else ever had a euro death knot invert on rappel? (not some lab test) Quote
Bug Posted July 3, 2002 Posted July 3, 2002 I once witnessed (it wasn't me I swear) a rappel where the survivor tied his prussik to the caribiner he was using as a brake bar. About half way down, the prussik grabbed and pulled the brake bar up above the main biner. This resulted in the rope coming down through the main biner at the survivor's harness, back up to the biner that was suspended by the prussik, and back down to the survivor's brake hand. Fortunately there was enough friction to maintain control and enough rope to allow him to descend to safe ground. He ran to the bushes and didn't come out for about ten minutes. Quote
Dennis_Harmon Posted July 3, 2002 Posted July 3, 2002 No, but a long time ago in a land far, far away I did have a girlfriend with the longest most beautiful hair that I was teaching how to abseil down a 30' boulder... needless to say, her hair got tangled in the carabiner-abseil system and it wasn't pretty. In fact, it was probably the most embarrassing, and heroic, day of my life. Not a real good way to sustain a long term relationship. Dennis Quote
thelawgoddess Posted July 3, 2002 Posted July 3, 2002 quote: Originally posted by Dennis Harmon: No, but a long time ago in a land far, far away I did have a girlfriend with the longest most beautiful hair [...] needless to say, her hair got tangled in the carabiner-abseil system and it wasn't pretty. i did that this weekend - oops! it really sort of sucked, but luckily i was able to unweight the device and reverse myself up the rope far enough to get my hair back and avoid having a huge clump of locks that was a few inches shorter than the rest. you can bet i'm gonna watch out for that one next time! Quote
Dennis_Harmon Posted July 4, 2002 Posted July 4, 2002 lawgoddess, I'm glad you got away as neatly as you did. I'm assuming that you're still in training and looking for a specialty. I used to skydive with an aviation attorney named Scott Hamilton out of Denver. I wonder if a recent grad couldn't establish a niche for themselves in the field of climbing law. You could sue manufacturers of climbing gear, land-owners, and individuals, ad.nauseum. Just a thought. Dennis Quote
Smoker Posted July 4, 2002 Posted July 4, 2002 It is well documented that when the fig 8 on a bight is used (rope tails out of the knot side by side)to join rope, that it can (the knot) invert and walk off the rope. If a figure 8 is used, make it a re-woven 8 with the tails exiting the knot on the standing line side. DRESS your knots well and leave some tail. S Quote
mattp Posted July 4, 2002 Posted July 4, 2002 Smoker has correctly stated what has always been the standard recommendation for the figure eight -- use it as a follow through knot with tails coming out opposite sides. I have never heard of anybody using it the "wrong" way, as they do when tieing the overhand on two rope tails to make a euro death knot instead of a water knot, but I can imagine somebody looking at the EDK and thinking it would be safer to use the figure eight. Thanks for the information, all, but I think I'll continue to use the EDK. I dress it carefully, tie it tight, and leave about 12-16" tails. One thing that hasn't been stated here is the reason why some prefer the knot -- that it has a very flat profile on one side so it pulls over an edge much easier than any other knot, and also that it is very easy to untie even after it has been used for a dozen rappels. An alternative knot that I find easy to untie, though doesn't have the flat profile for pulling over an edge, is the square knot - with the tails backed up with double fishermans. Do any of you tech guys have information suggesting this might not be a good idea? Quote
Dennis_Harmon Posted July 4, 2002 Posted July 4, 2002 I repel just about everyone, so I consider myself an expert on this issue. Don't die up there... it's not worth it. "Alive people are always smarter than dead people." Dennis Quote
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