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ChuQWallA
May 2, 2012, 11:10 PM
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Yes, I agree totally. In this case, I am specifically referring to 2 and 3 bolt anchors at the top of the climb, on the edge of the cliff. Everything that I have read suggests that 7mm cord is sufficient for this application, but reading some of the comments made me wonder. That said, I understand your point about anchors that are extended over an edge, and I agree that I would want something substantial to avoid cutting.
I have read a lot, and will continue to do so. I like to tie anchors to my pull-up bar and I often think about how I would anchor specific climbs.
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ChuQWallA
May 2, 2012, 11:18 PM
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I also want to point out that while this is sound advice, and I agree completely, it's more difficult than it sounds. Knowing which experienced people to believe requires a certain foundation of knowledge, and that's something I'm trying to build.
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danabart
May 3, 2012, 12:04 AM
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NEGuiding wrote: Jt is doesn't mention webbing at all, that was my point. And Curt, your thoughts are invalid here because all you like to do is argue on forums so move along. I recall mentioning something about soft southwest route ratings a few years ago on a forum and you flew off the handle. So you will be ignored. My thought on this is use static rope for extending anchors in a top rope set up people. Take this from a professional. Is it really that hard to buy a piece of static cord and retire your webbing? Your life is on the line and others if you're top-roping on it. Do you really want to take that chance? Don't listen to older climbers about webbing just because they say "I've been doing this for 25 years or 30 years or whatever" Just because you've been doing something for al ong time doesn't mean that you've been doing it right. If any of you are in the North Carolina, New York, Connecticut or New Jersey area, call me up and I'll put you on one of our top rope course for FREE. Mention this post and the class is yours free of charge and I guarantee you'll have your eyes opened to new fully trusted methods. My job as a guide is to educate the climbing community and that's what I do.
Yes, Curt likes to argue.
With people that are wrong.
And who don't know what they are talking about.
Like you.
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Gmburns2000
May 3, 2012, 1:20 AM
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ChuQWallA wrote: Thanks! I agree, it's very difficult to answer questions like this online. It just seems like every new thing that I learn raises more questions. After reading that people use 11.5mm static in their anchors I began to questions my own.
Just to be clear, as Jake noted, use the static line to build the anchor itself (i.e. - off trees, when the rope will run over the edge, etc). The 7mm cord that the Long book talks about (quad, sliding x, etc) is for when the anchor is built on the rock face (i.e. - not running over the edge, or when you're clipping to two bolts, etc).
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notapplicable
May 3, 2012, 2:09 AM
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Has RC.com ever actually gotten someone fired before? Some crazy shit has gone down over the years but this might be a first.
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Gmburns2000
May 3, 2012, 2:28 AM
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notapplicable wrote: Has RC.com ever actually gotten someone fired before? Some crazy shit has gone down over the years but this might be a first.
I've seen some serious attempts at doing just that, but I think you're right, this might be the first time it actually happens.
I'll be honest and say I never want someone to lose a job. I'd rather hear about people learning from their mistakes and fixing them.
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notapplicable
May 3, 2012, 2:40 AM
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Gmburns2000 wrote: notapplicable wrote: Has RC.com ever actually gotten someone fired before? Some crazy shit has gone down over the years but this might be a first. I've seen some serious attempts at doing just that, but I think you're right, this might be the first time it actually happens. I'll be honest and say I never want someone to lose a job. I'd rather hear about people learning from their mistakes and fixing them.
I completely agree and hope it does not go that far. People rarely make the same mistakes again and are usually more competent for having made them.
At least thats what I've found with my own missteps, of which there have been many.
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ncrockclimber
May 3, 2012, 3:21 AM
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Although I do not want to get anyone fired over the things that they posted on an internet forum, I am still flabbergasted at his behavior regarding the bolts at Crowders Mountain and his inaccurate and inflammatory comments about the CCC. He has yet to apologize for that. More importantly, I would like to hear how he is going to go about setting the record straight with the NC Parks Service. He stated that he informed them about the bad bolting at Crowders. Did he actually state that the CCC did a bad job, like he did here? If so, he really needs to step up and do some damage control.
I read the "apology." To me it looked like an attempt at damage control. If he really wants to move on, he needs to admit that he falsely accused the CCC, apologize for it, and do whatever damage control is necessary to fix the damage (minimal though it may be) that he has done.
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rgold
May 3, 2012, 4:47 AM
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A minor point about the reiterated claim by the NE "Guide" that a top-rope anchor has to be able to withstand a 20 kN load.
A top-rope fall on a single-pitch route cannot equal or exceed a fall-factor of 1/2 (and in any normal circumstance can't come anywhere near that extreme limit, which corresponds to the climber falling with enough slack to go from the top of the climb all the way to the to the bottom). With a stiff rope with a UIAA impact rating of 10 kN, a 180 lb climber would produce at most a 10 kN load (about 2250 lbf) on the anchor in that beyond-worse-case scenario. Assuming the belayer wasn't obtained from a cadaver bank, it is hard to imagine how one could get anywhere near 10 kN on a top-rope fall, and 20 kN is out of the ballpark.
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david_g48
May 3, 2012, 11:36 AM
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RG
I'm not sure that it is necessary to refute any individual claims by NEGUIDES. After the massive support he has received on this thread most anything he has said will probably be ignored. It is too bad that he went on this personal attack of webbing in such an abrasive ,destructive manner. I'm sure that he does have some valuable input if he thought it through and presented it properly, although I doubt we will ever see any. I do wonder if the board he is on has currently become a plank from which he must walk off.
As usual you and others have tried to refute him with sound reason and logic but, he was so hell bent on being right he would not listen or entertain changing his stance and tried to dazzle us with his credentials and facts which were abundant with falsehoods. I'm not sure that anyone who reads this thread will ever use his services.......I hate to see small cottage companies meet their demise in a time when we need them but he did contribute in a large fashion to any negatives that his company may receive.
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JAB
May 3, 2012, 11:39 AM
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This thread has made me confused about the terminology.
What is the difference (if any) between:
* Flat webbing
* Tubular webbing
* Nylon sling
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sandstone
May 3, 2012, 12:30 PM
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Flat webbing is woven in a single layer.
Tubular webbing is a tube, it has a hole in the middle. When the tube is pressed flat, there are two layers of material, compared to the single layer of flat webbing.
Slings are constructed by sewing or tying it into loops.
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kdelap
May 3, 2012, 1:23 PM
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For clarification on the AMGA's stance:
While a static line is used in single pitch curriculum for top rope anchors, it is not out of the question that tubular webbing could be used in conjunction with a static line or on its own.
There are many ways to solve problems. The AMGA "way", would be one that is safe and efficient depending on the given situation.
Feel free to email with any further questions.
Cheers,
Karsten
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rgold
May 3, 2012, 1:35 PM
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David, I'm not trying to get NEGuide to agree or disagree with me. Once statements have been made, they are "public," and if I believe, from what I know, that the statements are either misleading or incorrect, then my comments are about the statements themselves, which persist whether or not any one individual is around.
In the current case, I'm saying that it is virtually impossible to get anything close to half a 20 kN load on a single-pitch top-rope anchor. The claim is based on calculations made with a standard mathematical model which is known to overestimate the actual forces typically measured. Our own JT512 has written a handy impact-force calculator based on a more sophisticated version of these equations which he derived. The calculator, which replaces the now defunct Petzl version, is available at http://jt512.dyndns.org/impactcalc. Unlike some other calculators on the web, it gives correct answers (meaning correct in terms of the modeling assumptions employed).
20 kN is the UIAA standard for major-axis loads on carabiners. Perhaps NEGuide has interpreted this as also being the requirement for top-rope anchors.
This is an academic point, because real-world loads will be much less than even 10 kN.
By the way NEGuide has some highly respected guides working for his service. If you go out with Paul Curran or Al Joley, you will get the benefit of some excellent and very experienced climbing guides. Do not confuse the shortcomings of the owner/administrator with the competence of these individuals.
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snoboy
May 3, 2012, 4:44 PM
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majid_sabet wrote: ChuQWallA wrote: For reference, PMI 7mm cord is rated at 10.7 KN, and with 2+ legs on the anchor it should easily be over 20KN. no you got an F so far on your math A knot in the system takes 30% so 2 x 10kn =20-6=14 kn
A cordellete anchor usually has two strands per leg, no?
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majid_sabet
May 3, 2012, 5:03 PM
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snoboy wrote: majid_sabet wrote: ChuQWallA wrote: For reference, PMI 7mm cord is rated at 10.7 KN, and with 2+ legs on the anchor it should easily be over 20KN. no you got an F so far on your math A knot in the system takes 30% so 2 x 10kn =20-6=14 kn A cordellete anchor usually has two strands per leg, no?
assuming you use two pro or bolts then
10x2 + 10x2 = 40-30%=28KN so you are above 20kn and safe however, the last piece connecting you to an anchor sets the safety rules so if the last biner is rated at 15 kn, your entire anchor is rated to 15kn .
when I teach anchor classes, I always ask my students to construct 40kn anchors for our application but then I give them a 15kn locking biner without them looking at it and 95% of the time when i asked "what your anchor is rated at the master point, ?" they say 40kn
But then I show them the biner and says 15kn and they fail the anchor course
(This post was edited by majid_sabet on May 3, 2012, 5:08 PM)
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tower_climber
May 3, 2012, 5:51 PM
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majid_sabet wrote: when I teach anchor classes, I always ask my students to construct 40kn anchors for our application but then I give them a 15kn locking biner without them looking at it and 95% of the time when i asked "what your anchor is rated at the master point, ?" they say 40kn But then I show them the biner and says 15kn and they fail the anchor course
Now that's just downright mean-spirited.
Note to self: bring a 53kN steel screwgate to Majid's anchor class...
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ChuQWallA
May 3, 2012, 7:15 PM
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This has been a fruitful discussion for me, and I want to say thank to everybody who responded.
I have 4 follow-up questions:
1) Is a knot required at each carabiner for each leg to be considered 2 strands (10x2). I'm specifically asking how do we measure the rating of the strands in KN. I'm assuming yes, because otherwise each leg is really one strand that can fail? Or is the load balanced between the two strands regardless? Looking both online and in the Leubben book I see some with knots and some without. The equalette usually seems to have them where the cordelette doesn't. I'm assuming that this is because the equalette is equalized at the protection where the cordelette is equalized at the power point.
2) How do I account for knots in the system. I see that Majid uses 30% reduction as a rule of thumb, which is around the average that I found online for various knots. If I use a 4 point equalette anchor, there would be 2 overhand knots at the power point, a double fisherman's knot to create the loop, and a clove hitch at each piece of protection, for a total of 7 knots. How should I think about the reduction in strength of the system? Is each leg considered on its own?
3) What's a good way to remove slack from one leg of a cordelette or equalette anchor? If one leg is slack, because bolts aren't at the same height for example, can I tie a knot to shorten the final strand of the anchor so that all bear weight? I'm thinking 8 on a bight or alpine butterfly, but wondering what the preferred method is?
4) Finally, wouldn't you use a minimum of 2 locking carabiners at the power point? Shouldn't you fail them for introducing a single point of failure into the system anyway?
This is some knot data that I found on the strerling rope site for reference.
In reply to: Here is a list of some common knots and the translating remaining rope strength. Knot Strength NO Knot 100% Double Fisherman's 65-70% Bowline 70-75% Water Knot 60-70% Figure 8 75-80% Clove Hitch 60-65% Fisherman's 60-65% Overhand 60-65%
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majid_sabet
May 3, 2012, 7:23 PM
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tower_climber wrote: majid_sabet wrote: when I teach anchor classes, I always ask my students to construct 40kn anchors for our application but then I give them a 15kn locking biner without them looking at it and 95% of the time when i asked "what your anchor is rated at the master point, ?" they say 40kn But then I show them the biner and says 15kn and they fail the anchor course Now that's just downright mean-spirited. Note to self: bring a 53kN steel screwgate to Majid's anchor class...
SMC and a UK made ASC biner offer 76 kn biner
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ncrockclimber
May 3, 2012, 7:40 PM
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Chuq.
I applaud your desire to learn. There are a lot of knowledgeable folks on this site, but there are also a lot of inexperienced individuals trying to position themselves as experts.Some of them do it quite convincingly. A few of them have extremely high post counts or falsely claim to have SAR or guiding experience. I would posit that as a beginner, you are probably not able to discern between who is legit and who is not. I would urge you not to depend on an internet forum for technical advise.
Your questions demonstrate that you are very concerned about safety. That is a great starting point. You can find the answers to many of your questions in books. Reading is a great way to supplement your skill set. However, in my opinion, the best way to gain the skills necessary to be a safe and competent climber is by finding an experienced mentor or paying a professional for instruction. A mentor or guide will not only answer your questions, but help you to discern what questions you should be asking and what skills are most valuable to have. If you don't have a mentor, many folks on this site can point you in the direction of good guides in your area.
Best of luck, Chug.
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cracklover
May 3, 2012, 7:53 PM
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ChuQWallA, why don't you create a thread to discuss your anchor questions in the Beginner (or Lab, if you want more technical answers) forum. That way people who are interested in helping will see it, and those who are looking to follow this thread will not.
Cheers!
GO
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johnwesely
May 3, 2012, 8:35 PM
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ncrockclimber wrote: Chuq. If you don't have a mentor, many folks on this site can point you in the direction of good guides in your area. Best of luck, Chug.
I know a great guy at Northeast Mountain Guides.
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viciado
May 3, 2012, 8:39 PM
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In reply to: I know a great guy at Northeast Mountain Guides.
You should be able to turn up lots of google hits if you don't have the website... heh heh.
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ChuQWallA
May 3, 2012, 9:52 PM
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Thanks NCRockClimber,
Your suggestions are well received. One thing that I pointed out earlier, something which you also point out, is that it's difficult to determine who to believe at times. I have taken an anchors course from my local REI, hired a guide, and gone out with local groups with varied experience levels. And as we've both said, it's difficult to know who to believe. Let me reassure you that I would never take information directly from an internet forum and trust my life to it. I simply try to collect as much data as I can, from diverse sources, so that I can make my own informed decision about how to proceed and who to believe.
Cracklover,
That's an excellent suggestion. I'll consider creating a new thread in the future.
C
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