ההתכתבות בנושא טבעות לא ננעלות ואמצעי חיכוך כן

מתוך Climbing_Encyclopedia
קפיצה אל: ניווט, חיפוש

כאן נמצאת ההתכתבות עם בעל האתר www.geir.com שטען שאין בשום אופן להשתמש באמצעי חיכוך ננעלים אוטומטית לחבל כפול עם טבעת לא ננעלת. על השאלה הזו ענינו בנפרד גם כאן.

hi

i've stumbled on your "The Climbing Mythbusters" page, and liked most of it, and to most of it i agree.

i'd like to raise one question, however, about auto locking devices used with non-locking biners.

first, i'll introduce myself. my name is Micha Yaniv. i've been climbing for 20 years, and have been a mountain guide for 16 out of them. I climbed many season, routes and summits and in the alps, as well as in Peru and summited Everest on 2006 i ran a many climbing courses, quite a few guides courses, for climbing guides, mountain guides and canyoning guides. I am a senior guide of the IDF climbing and rescue school. also, i ran numerous experiments over the years, on knots, pieces of gear as well as on large rescue systems.

i have a BSc in physics and Math, MSc in Ecology, and am working on my PhD in Geophysics. i think i have pretty good understanding of how most pieces of gear work, and of most things that should be taken into account when analising climbing situations.

also, i have been working on an extensive "climbing encyclopedia" (it can be found here: wiki.imga.org.il) but it is in Hebrew, so i guess, not very interesting to you...

I am just writing this, to let you know i am not just objecting to your statement about belaying with a non-locking biner, but i truly fail to see the importance, and have some experience to back it up.

ok, the main question is: how is this any different from using a rack as a belay device? or a brakebar with a piton or ice-screw as the bar? all those cases are improvisations, and are not considered common practice, of course, but in essence, they are ok to use.

it is clear to me that there is no risk of the a non-locking biner braking when used like this. only reason not to use one, is that the rope may unclip itself. what are the chances of that happening? i've been using many devices over the years and have never seen anything like that happen. of course, this is no proof that it cannot happen, but has it ever happened?

i asked all my friends and ran a search, and could not find a singe case it happened. again, maybe not good enough. ok, let's try to think about it: as long as there is minimal load on the device, the rope cannot unclip itself. more even: the binner cannot even turn or flip, so that the gate becomes closer to the loop of rope. now, the loop of rope should be large enough to pass over the gate. that should be easy for a pretty rigid rope, such as old static ropes or ropes that have bad knotability. with dynamic ropes, and especially thin dynamic ropes, such as commonly used for long routes (double and twin ropes), i think that this risk is negligible.

i do not object to using a locking biner for belaying with an auto- locking device, of course, but i would not strongly claim that using non- locking biners is very bad pactice ande extremely dangerous.

i am fully aware to the fact that i might be missing somethibng, and i'd be glad to hear your thoughts,

Mica Yaniv Middle East Mountain Guides office:00-972-2-6586194 cell: 00-972-54-7625243 www.memg.co.il


hello mica,

thank you for your reply regarding my website. i am honored that someone of your experience has read through my page and took such time to think through it. it is truly wonderful to engage such an experienced and bright person.

i agree that it is highly unlikely that the rope will become unclipped from the nonlocking carabiner when used to retain the rope in a reverso, guide atc, or other plaquette device. i also agree that i have found no documented cases in which this has occurred specifically with a plaquette device. while i recognized the sheer improbablity of this, i wrote this article as it appears on my website for a couple of reasons:

1) the vast majority of people that read through my site have less than a tenth of the experience and knowledge that you have. as a basic principle, i felt that it was important to stress the idea that if one's life is dependent upon a single carabiner, it should be a locking carabiner. if i were to propose the idea that use of a nonlocker is safe here (and under the watchful eye of an experienced mountain guide i'm sure it is), less experienced climbers might also deduce that it is acceptable to use a single nonlocking carabiner to rappel with, to tie in with, or to use for a redirected top rope.

2) while i again agree that it is highly unlikely that the rope could become unclipped from a nonlocking carabiner used in a plaquette, clearly the probability of the rope becoming unclipped is less likely when using a locker. while there have been no reported cases where this has happened with a plaqette in autolocking mode, there have been cases where nonlockers have come unclipped from the top piece during a lead fall, during rappels, and cases where nonlockers have unclipped from bolts during traverses. (i myself witnessed the latter happen). i have also read a documented cases where an autolocking carabiner came unclipped during a rappel, leading to a catastrophic fall. while i agree that these cases involve much more relative movement between the rope and the carabiner, it suggests to me that use of a locker in the plaqette device may prevent an unforeseen accident. again, this applies to the novice and intermediate user.

i do think, however, that your comments completely valid. it would be interesting to set up a mechanical simulation with thousands of falls to see if a nonlocker ever becomes unclipped.

on another note, i would be interested in your comments on the article i have posted on my website regarding gear selection. you can download the article from my website at www.geir.com/Article.doc.

respectfully,

geir hundal



hi geir

hi geir

thank you for a quick and detaile reply. i'll be glad to look through your article. i'll let you know what i think.

now, to answer to your arguments:

1 and actually, 2, so i'll regard them combined, with your permission. it is also my opinion that one should write, aiming at the unexperienced rather than the experts. but in stating something as an expert, you might think that beginners will take it as is, rather than think about it. since you agree, in general, that it is highly improbable (i would put it more strongly - probably impossible) for a rope to unclip itself from an auto-locking belay device, i fail to see how it is connected with another general case of using a locking biner as a rule, when rappeling or belaying. the main reason to use a locking biner, is not that the rope may unclip itself, but that the biner might open. when the gate is open, the biner is roughly 2/3 it's designated strength. with a lightweight, old, worn, and possibly damaged biner, this can become a hazard. i actually know of one case where a supposedly good biner (it was not damaged or worn in any way visible) broke under a load of one person when opened while it was loaded. i was usked to give an expert statement in court about this case).

so, it is actually more important to use a locking biner to attach your plaquette to the anchor than to use one on the ropes. the risk of the rope biner opening makes it no more dangerous, because it is no used as a biner at all! it is used as a bar. ans as such, the strength of the biner has no relevance.

so, my point is, that the case is different.

as i see it, there are three categories of cases:

1. when the rope is not loaded part of the time, like rope running through runners, top-rope with some slack etc. the rope can clip itself, and if you just one point (like in top-rope, both with the belayer and on the anchor), do anything in your power to prevent the opening of the gate, like use a non- locking biner. if you cannot, as while leading, avoid back-clipping to reduce that risk.

2. you have one point of attachment, and that point is a biner and it's loaded. in this case, the thing to avoid is the hazard of the biner breaking if the gate opens. this applies to high load systems like rescue systems, omega lines etc. but also when rapping or swinging on a pendulum traverse. in this case, you want to use a non-locking biner, but not to avoid unclipping, but to avoid the relative weakening of the biner that happens with the gate opening.

3. the third case is what we're interested in. you use the spine of the biner as a bar. the biner can be broken, it can be open, it can be a rod or a tube of metal [like an ice-screw or a piton, or a bar taken off a brake-bar (Petzl Rack, for example)]. since the rope going through the belay device, and therefore the biner is partly loaded (minimum load is the weight of rope below the anchor), the risk of unclipping is negligible.

no, it is not that i have an objection to using locking biners in this case, i just think it is a non-issue. while not having much direct effect on safety, it does have a negative effect on safety, indirectly. if you pay attention to only using a locking biner at the anchor, it means you have an extra locking biner, and cannot use one of your runners or free biners. if it takes a little more time pinpoint that one biner in your rack, it means you spend more time on that, and you are slower at setting your belay and slower on the route in general. it seams like a small price to pay for a possible improvement of ones safety, but i think it goes deeper that just that.

it seems to me that the main thing that you are saying is: always use a locking biner. the exact situation is not important, just use locking biners. the beginners that read your site might take it like that. i would think that in this case, it is not as simple as that, and that it's better to teach people the reasons why this case is different than others.

two more things. i would thing that when people get to the point of using auto-locking devices, they are not novices anymore. this is my recommendation in general. someone would use that kind of gear only when they get to the point of multi-pitch, maybe trad, probably twin or double rope leading. therefore, it is ok to let them know of the subtlety of the situation.

lastly, i'd like to say that i might be wrong. there may be a case in the future, when a rope unclips itself in exactly the same situation. i am in no way too arrogant to avoid acknowledgment of that possibility. even tough, i will continue teaching people according to what i know. this way, i believe they will be aware of the difference, and they will pay attention to having the rope loaded at all times, so it cannot unclip itself even if it wants too very badly...

mica

PS. my cow's tail for the everest climb had one, lightweight, non- locking bine. this was a decision, of course, not chance. the use of locking biners with thick mittens is too time consuming, as well as the use of two biners, not to mention the weight. so, i follow my own advice, usually.

cheers

Mica Yaniv Middle East Mountain Guides office:00-972-2-6586194 cell: 00-972-54-7625243 www.memg.co.il

hello mica-

good to hear back from you. first, thanks for reading my article and your kind comments. i will take your comments into account as i revise the article and software.

now to answer your comments regarding our discussion of nonlocking carabiners, particularly with respect to their use in plaquette devices:

1) while i have not read the black diamond study conducted on dropped carabiners, i read (and have a copy of) a similar study carried out by rei. interestingly, dropped carabiners were also slightly stronger than their non-dropped counterparts. i will request a copy of black diamond's study and revise my carabiner strength notes accordingly.

2) regarding this paragraph:

since you agree, in general, that it is highly improbable (i would put it more strongly - probably impossible) for a rope to unclip itself from an auto-locking belay device, i fail to see how it is connected with another general case of using a locking biner as a rule, when rappeling or belaying. the main reason to use a locking biner, is not that the rope may unclip itself, but that the biner might open. when the gate is open, the biner is roughly 2/3 it's designated strength. with an lightweight, old, worn, and possibly damaged biner, this can become a hazard. i actually know of one case where a supposedly good biner (it was not damaged or worn in any way visible) broke under a load of one person when opened while it was loaded. i was usked to give an expert statement in court about this case).

so, it is actually more important to use a locking biner to attach your plaquette to the anchor than to use one on the ropes. the risk of the rope biner opening makes it no more dangerous, because it is no used as a biner at all! it is used as a bar. ans as such, the strength of the biner has no relevance.

we have a difference in opinion here. the main point i stress in teaching about locking vs nonlocking carabiners is that a locker should be used any time a person's life/safety is dependant upon a single carabiner. this includes while rappelling with a tuber, belaying a leader with a tuber device, attaching to an anchor point, and to hold the ropes in the plaquette device. in my thinking, reduction of the liklihood of a rope becoming unclipped is just as important as maintaining a closed gate for carabiner strength.

i suspect that a greater number of accidents occur from ropes becoming unclipped than from failure of carabiners due to strength reduction when gaits open. although i fully admit this is just a guess on my part, and have not yet done research to conclusively know this. in my personal experience (which is not as extensive as yours) i have seen ropes become unclipped three times, but have not witnessed a carabiner failure due to an open gate.

i do agree with you that it is unlikely that a nonlocker, used as a bar in a plaquette, is surely strong enough regardless of whether its gate is open or not. in pull tests that i have observed, rope failure always occurred before carabiner failure when a plaquette is pulled to failure.

i'm not fully convinced that the contant tension exerted on a nonlocker in a plaquette is sufficient to prevent rotation and possible unclipping (although it is very unlikely). i will send a series of photos to demonstrate what i have in mind, although i cannot send them to you right now as i'm in an aircraft, and i don't think the stewardesses will allow me to set up and photograph what i have in mind. i'll send more on this after i've returned home.

3) regarding these paragraphs:

as i see it, there are three categories of cases:

1. when the rope is not loaded part of the time, like rope running through runners, top-rope with some slack etc. the rope can clip itself, and if you just one point (like in top-rope, both with the belayer and on the anchor), do anything in your power to prevent the opening of the gate, likk use a nomn- locking biner. if you cannot, as while leading, avoid back-clipping to reduce that risk.

2. you have one point of attachment, and that point is a biner and it's loaded. in this case, the thing to avoid is the hazard of the biner breaking if the gate opens. this applies to high load systems like rescue systems, omega lines etc. but also when rapping or swinging on a pendulum traverse. in this case, you want to use a non-locking biner, but not to avoid unclipping, but to avoid the relative weakening of the biner that happens with the gate opening.

3. the third case is what we're interested in. you use the spine of the biner as a bar. the biner can be broken, it can be open, it can be a rod or a tube of metal [like an ice-screw or a piton, or a bar taken off a brake-bar (Petzl Rack, for example)]. since the rope going through the belay device, and therefore the biner is partly loaded (minimum load is the weight of rope below the anchor), the risk of unclipping is negligible.

clearly, your experience level and manner of explanation are both excellent. i agree with everything above, except that i would add again that i equally value the two major advantages of locking carabiners, namely the decreased risk of unclipping and the decreased of strength reduction due to accidental gait opening.

4) regarding this paragraph:

it seems to me that the main thing that you are saying is: always use a locking biner. the exact situation is not important, just use locking biners. the beginners that read your site might take it like that. i would think that in this case, it is not as simple as that, and that it's better to teach people the reasons why this case is different than others.

as i mentioned above, my feeling is that a locker should be used if it is the only carabiner in the system assuring a person's safety. in all other cases, a nonlocker is an excellent choice. my thinking here is a result of both personal experience and the instruction i recieved in my own certification courses. although i also think that an expert has the experience and judgment to vary from this line of thought, and will certainly be making a valid judgement. i just feel this is a simple rule to teach by.

5) regarding this paragraph:

lastly, i'd like to say that i might be wrong. there may be a case in the future, when a rope unclips itself in exactly the same situation. i am in no way too arrogant to avoid acknowledgment of that possibility. even tough, i will continue teaching people according to what i know. this way, i believe they will be aware of the difference, and they will pay attention to having the rope loaded at all times, so it cannot unclip itself even if it wants too very badly...

i would also like to admit that my line of thinking may prove to be wrong. clearly you are an exceptionally experienced guide and a quite intelligent person. i respect your honesty and thoughtful approach to guiding.


on a different note, i noticed you climbed everest! fantastic! did you summit?

respectfully, geir hundal


oh, and about the binners. i tried o find the BD experiment on the web but could not. it was in climbing magazine some years ago. but that might interest you/: i talked to this expert in Metalurgy some time ago, and asked him about the binners. he said that: 1. in few cases, the biner may even become stronger. 2. in most cases, nothing will change. 3. in a few cases it may fracture and become substantially weaker.

the percentages depend on the batch size, repeatability, stability of manufacture conditions and quality control. oh, and the quality of the raw material they start with.

his recommendation was: if it's not extremely expensive (which binners aren't), scrap it if it falls.


מיכה יניב מדריכי הטיפוס של המזרח התיכון

בבית: 02-5346344 במשרד: 02-6586194 בנייד: 054-7625243

בקרו באתר שלנו: www.memg.co.il


great - thanks for the info. i'll contact BD directly some time after i return from my climbing trip...

sincerely, geir