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Peter
climber
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Nov 26, 2008 - 03:34am PT
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Fet - I don't understand what force the PAS increases compared to a cordolette or sling. I belay off my harness either way, and usually clip the rope to a power point an arm's length above my waist when belaying the second and at least until the leader has a couple of good pieces in. The only time the second is clipped directly to the anchor is when we're switching leads and there's no risk of a dynamic fall. If you tie in to the anchor with the rope how much force is absorbed by the short length of rope between the anchor and your harness?
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Karl Baba
Trad climber
Yosemite, Ca
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Nov 26, 2008 - 04:17am PT
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I agree Peter, the PAS static issue is a non-issue.
Just like many of these geek threads that don't consider enough practical issues.
The real issue on using a PAS to connect the pieces on your belay is this: You can't escape the belay in an emergency without basically disconnecting your anchor!
Same goes for folks who use the rope to anchor directly to the pieces.
Now for folks who worry about the mechanical advantage effect of clipping the rope through the top piece of the anchor, answer me this, if you are at a hanging belay or are just putting your weight on the belay to get off your aching feet, will the multiplier effect still put twice the force on the belay. I think not. If you are hanging on the belay already, the forces on the anchor remain the same.
Personally, I belay the second off the anchor with a gri-gri. I could escape the belay in 1 second, I can haul with almost no set-up, I can take pictures without risking dropping the partner, and if they fall, it's no effort to hold them.
Then I belay the leader off my harness for better dynamics in absorbing the "real" fall,.
peace
Karl
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healyje
Trad climber
Portland, Oregon
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Nov 26, 2008 - 04:29am PT
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This was one (ala Trango) of a couple of ideas I threw up for three-points during the extended RC anchorfest. It, and all the other groovy contributions from folks, were great fun for an evening at home on the InterWebbing - the problem is, I simply never really bother out on the rock, and rarely ever have an independent piece of cord with me. When I do, it goes into an equalette which I like way more than [tied] cordelettes which I never did like and never used.
P.S. I agree with Karl that weaving a PASS-like device into the anchor is a decidely bad idea.
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NoRushNoMore
climber
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Nov 26, 2008 - 05:24am PT
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Peter, I am with you on your method, this exactly what I do most of the time.
Small suggestion: I clove hitch the longest leg of the anchor with the rope and clip PAS to the remaining two pieces. If anything this gives you close to even distribution between pro.
While escaping the belay argument is thrown around a lot it's not that practical, what do you do once you are free from the belay? Free solo to help your hanging partner? Ascend with prussics?
Nah, you a lot more likely to lower him down till you run off the rope and then disassemble your anchor and climb up till you meet in the middle
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the Fet
Knackered climber
A bivy sack in the secret campground
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Nov 26, 2008 - 01:35pm PT
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Peter, sorry I mis-read your post, it sounded to me like you didn't use the rope at all to connect to the anchor, just the static PAS.
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JohnRoe
Trad climber
State College, PA
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Nov 26, 2008 - 02:30pm PT
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Karl wrote: "Now for folks who worry about the mechanical advantage effect of clipping the rope through the top piece of the anchor, answer me this, if you are at a hanging belay or are just putting your weight on the belay to get off your aching feet, will the multiplier effect still put twice the force on the belay. I think not. If you are hanging on the belay already, the forces on the anchor remain the same."
Karl, I think that your argument is correct as long as the fall is not hard enough to lift you (the belayer) up off the hanging belay. In this thread, people have been talking about braking forces of many kN. These would lift you off the hanging belay unless you had a separate downward-force anchor (and in either case the "pulley effect" argument would apply).
John
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Karl Baba
Trad climber
Yosemite, Ca
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Nov 26, 2008 - 02:49pm PT
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John wrote
"Karl, I think that your argument is correct as long as the fall is not hard enough to lift you (the belayer) up off the hanging belay. In this thread, people have been talking about braking forces of many kN. These would lift you off the hanging belay unless you had a separate downward-force anchor (and in either case the "pulley effect" argument would apply). "
What I'm saying is, you're hanging on the anchor. If you get pulled up by the leader falling and it's directed through the anchor. yes, that weight goes on the anchor but was on there anyway. You're pulled up so that weight gets subtracted and reapplied in the pully situation. End result, equal.
Mostly irrelevant to me anyway except intellectually. Granite is Bomber! Sandstone guys can have fun worrying. I crap my pants in Sedona
Peace
Karl
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JohnRoe
Trad climber
State College, PA
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Nov 26, 2008 - 03:24pm PT
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Hi Karl,
I think that if the belayer is being pulled (accelerated) upwards, the force being applied through the rope to achieve this acceleration is greater than the belayer's weight. So, the force applied to anchor by the belayer while the fall is being stopped is greater than the weight "that was there anyway". Does that make sense?
Happy ThanksGeeking :-)
peace
John
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tito
climber
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Nov 26, 2008 - 03:34pm PT
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> Now for folks who worry about the mechanical advantage effect of clipping
> the rope through the top piece of the anchor, answer me this, if you are
> at a hanging belay or are just putting your weight on the belay to get off
> your aching feet, will the multiplier effect still put twice the force on the belay.
> I think not. If you are hanging on the belay already, the forces on the anchor
> remain the same.
While I think I understand the point you are trying to make, your conclusion appears to be preposterous. Your text seems to say: if you are at a hanging belay, i.e. all your weight is on the anchor and the leader clips a piece of the anchor and then falls, "the forces on the anchor remain the same." I'm pretty confident you don't believe that.
Also, not all your weight is going to be hanging on the top piece of the anchor, is it? Presumably you have other pieces in your anchor. So when the leader falls, how much additional force does the top piece get hit with?
> Fet - I don't understand what force the PAS increases compared to a cordolette or sling.
Suppose one piece of your anchor blows. Suddenly the anchor extends and you are brought to halt on a relatively low stretch piece of sling as your PAS comes tight to the other anchor point. Compare that to the situation where you build an anchor with a cordalette made out of 7mm perlon and clip a length of rope to the power point to tie in:
1) If a piece of the anchor fails, the extension is probably not going to be as great with a cordalette.
2) The cordalette will stretch more than the PAS reducing the forces on the remaining anchor.
3) The length of rope you tied into the the power point with will stretch reducing the forces on the remaining anchor
How much will the cordalette plus rope tie in reduce the forces on the anchor? Is it significant?
> I've been using the equalette for over a year and I've come up with a variation
> that allows you to avoid using 2 carabiners at the "power point".
Have you considered what will happen if the left hand anchor fails? If that happens, the power point biner will impact the left hand figure eight and try to pry it apart. One reason you should prefer an EDK for a rappel knot instead of a figure eight is because the figure eight rolls easier. In your setup, I think it is highly likely the eight would roll at least once after the power point biner impacts it, and since the tail sticking out of the left hand knot is short, it will come untied. What does that leave you with?
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Karl Baba
Trad climber
Yosemite, Ca
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Nov 26, 2008 - 04:42pm PT
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J Roe Math Bro write
'Hi Karl,
I think that if the belayer is being pulled (accelerated) upwards, the force being applied through the rope to achieve this acceleration is greater than the belayer's weight. So, the force applied to anchor by the belayer while the fall is being stopped is greater than the weight "that was there anyway". Does that make sense?
Happy ThanksGeeking :-)
peace
John "
Since you are the Math Master, let's simply it to compare this.
1. Let assume the leader clipped the powerpoint of a cordalette anchor as a directional, climbed up 15 feet and fell. The belayer is also hanging low on the cordalette.
versus
2. The belayer is hanging there and belaying off the powerpoint with a gri-gri (assume static belay even though they slip a bit)
How much pully effect in #1 versus #2
Obviously a softer catch if the leader falls right onto the device of the belayer (if he catches it, and then the other factors about escaping the belay or hauling the leader back up come into play
Peace
Karl
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Nick
climber
portland, Oregon
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Nov 27, 2008 - 09:30pm PT
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I have been sitting here waiting to to eat the bird and drinking beer after a wonderful hike with the family today. Perhaps I have a few under my skin and this is ill advised, but.. My daughter and I went out to the micro training wall and constructed a marginal anchor using my equalette then took a couple of photos. Thought I would post them up for a proper holiday thrashing. I can see a couple of things wrong with it like the clove hitch from the pink tricam is not quite right, but hell I built this thing quick with a skin full of beer.
Perhaps you can't tell but the locker on power point is on doubled webbing.
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Karl Baba
Trad climber
Yosemite, Ca
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Nov 27, 2008 - 09:59pm PT
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Thanks for taking the time to photograph and post Nick.
Two questions or observations,.
#1 Time is safety in climbing. How fast can you construct an anchor like that? Do you do so for regular climbing.
#2 Anchor seems to eat up a lot of vertical space. How often is that a downside at actual anchors. (particularly fixed one that tend to be close to a stance or ledge)
3. Do you clip a directional in the anchor if there is a lead-out off the belay? If not, is the anchor more likely to fail from a factor 2 on your belay loop or by ripping the whole anchor?
Just for the sake of discussion
Peace
Karl
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WBraun
climber
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Nov 27, 2008 - 10:44pm PT
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Nice anchor Nick.
But I still prefer the non-anchor Walt and Stretch gave as we all were sliding towards our doom.
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Largo
Sport climber
Venice, Ca
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Topic Author's Reply - Nov 27, 2008 - 10:55pm PT
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Nice anchor.
I think all these long-winded discussions are good because they bring into sharper focus various elements that have long been glossed over or explained away - often incorectly - with "traditional wisdom" or daft lab tests, and what's more, so long as we keep fiddling around with various anchoring arrays, someone, at sometime, is going to come up with somthing amazing.
Happy Thanksgiving.
JL
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Nick
climber
portland, Oregon
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Nov 27, 2008 - 11:59pm PT
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Karl,
#1 Time is safety in climbing. How fast can you construct an anchor like that? Do you do so for regular climbing.
This anchor can be made real quick. The equalette is a pre tied double nylon runner which I rack like I do all the other runners on my harness. Most of the time it is literally just clip the ends to your two best pieces place an upward piece below and clip the belayers rope into that as well. Everything else is straight off the rack nothing fancy. I also like to use the equalette as a tied daisy to anchor with when routes require multi pitch raps. I use it on most trad anchors.
#2 Anchor seems to eat up a lot of vertical space. How often is that a downside at actual anchors. (particularly fixed one that tend to be close to a stance or ledge)
I have not had too much issue with that yet. Although I have only used it on maybe 30 or 40 anchors. It is not even as long as a regular runner because of the knots. I do wish it was a little shorter for racking, but I have never seen a 1.5 length nylon runner.
3. Do you clip a directional in the anchor if there is a lead-out off the belay?
Hell yeah, I clip a directional. I out weigh my daughter by 50 lbs and one of my main climbing partners is 6'4" 235. Most of the time I use the rope.
If not, is the anchor more likely to fail from a factor 2 on your belay loop or by ripping the whole anchor?
Neither I hope ....I have no idea. I usually don't clip the anchor as the first piece unless it is a big fat bolt. I always belay off my belay loop, hoping that my body on a stance will take some of the blow off the anchor.
Time to eat pie.
Happy Thanksgiving!
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Karl Baba
Trad climber
Yosemite, Ca
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Nov 28, 2008 - 01:36am PT
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As I have said before (but don't actually do because my anchors in granite are almost always bomber)
Want a serene anchor? Here's my idea, if you REALLY need the best anchor protection on some sketch rock, just clip a shorty screamer to each piece (or at least one or two of them) and rig a regular cordalette anchor to the screamers.
If the system gets stressed enough to be an issue, the screamers will extend, leading to perfect equalization with no shock load, and also absorb energy from the situation at the same time.
Discussed here
http://www.supertopo.com/climbing/thread.html?topic_id=577246
Peace
karl
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Mighty Hiker
Social climber
Vancouver, B.C.
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Nov 28, 2008 - 02:23am PT
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Karl describes the "scream-o-lette". Sound effects to match if it doesn't work.
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George R
climber
The Gray Area
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Dec 10, 2008 - 11:21pm PT
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On Nov 23rd, rgold wrote:
" John, one thing that worries me, and I have to apologize profusely for not catching it early on, is that Jim's tests on the effect of elongation in the anchor, the ones that lead to the conclusion that elongation doesn't matter, do not seem to me to be properly configured to test the real situation. There was too much energy-absorbing rope in the system, relative to the amount of elongation, leading to insignifcant changes in fall-factor and so a conclusion that might not be appropriate for real anchoring situations. In a real situation, it is the belayer's anchor strand that will have to absorb the belayer's fall (plus whatever load the belayer is holding at that instant). Minimally, the anchor strand will have to absorb a fall by the combined weights of leader and belayer. If that anchor strand is short, say a foot and a half, and if the elongation in the anchor is, say, six inches, then you still have a fall factor of 1/3 with something like 350 pounds, and there is no way this isn't going to load the anchor significantly. This means that the intelligent use of sliding systems ought to involve tying into them as long as possible, given the nature of the stance. "
Right. A general conclusion that anchor rigging elongation (aka extension) is harmless is not supported by any test data.
The Long/Sterling tests simulate a situation in which a climber is rope soloing without a haul bag or belayer or any other significant weight on the anchor. This tells us almost nothing about what happens when the belayer (and/or 3rd climber, haul bag, etc.) falls due to extension. Depending on the circumstances, such a fall could have a very high fall factor (possibly greater than FF 2) on a tied-off rope (no belay to slip and limit force). Or worse yet, onto a static tether such as a sling or daisy chain.
Rock & Ice magazine also did some tests to examine the anchor extension question. (See Rock & Ice #135, July 2004). Their conclusion was extension is dangerous. They also made the error of generalizing from one situation to all situations, however their tests are more relevant to the situation we're concerned with. The R&I test was perhaps extreme (no dynamic rope at all) but they more accurately modeled the situation of the belayer falling on to the belay anchor due to extension.
The key to reconciling the differing test results and to understanding the extension problem is the Fall Factor. In the Long/Sterling tests, extension resulted in insignificant additional force placed on the remaining anchor point. Exactly what we should expect in that situation, because the fall factor was not increased much by the extension. In the R&I tests, the fall factor was high and no dynamic rope was involved, so extension caused a large force on the remaining anchor point. Again, just what should be expected.
It should be emphasized that it is the belayer (and/or other large masses attached to the anchor) that matters. A falling climber may have enough dynamic rope out to keep the fall factor low and minimize additional force from anchor extension. The belayer, third climber, haul bag or whatever may not. They will often be tied (not belayed) to the anchor with relatively little dynamic rope or perhaps none at all. Fall factors and forces may therefore be very high. The issue is how much dynamic rope compared to how much extension with respect to each falling mass in the system.
The Long/Sterling tests and the Rock & Ice tests each tell us something, but not everything, about the potential dangers of anchor rigging extension. If we apply the fall factor concept, and consider ALL the significant masses that are involved in a given situation, we can draw the correct conclusion for that situation.
Again, the issue is how much dynamic rope compared to how much extension with respect to each falling mass.
G
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Karl Baba
Trad climber
Yosemite, Ca
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Dec 11, 2008 - 12:38am PT
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Thats a fine post and one that should be reposted to the thread regarding if a leader should clip a directional into the anchor or not. A fall directly on the belayer which results in a pulled anchor piece which leads to extension would seem to lead to the worst of all worlds in terms of forces
Peace
Karl
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The Guy
Trad climber
Portland, OR
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Jun 14, 2010 - 03:15pm PT
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bump
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