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chriss
Feb 28, 2005, 10:23 PM
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In reply to: The force on those gates is minimal. If the rope were to pull the bottoms of the biners together, the tops of them would separate. It's not like the tops of the biners are welded together, they're just both through the same sling. Plus, the biners can shift side to side relative to each other a little bit. In short, there is zero danger in that setup. In comparison, the danger of having one single locker that you cannot see from the ground which everything goes through, is absolutely unacceptable for a toproping setup. Any and every book that discusses TR setup will say so. But I'm happy to provide documentation if you want. GO
The "tops" cannot "seperate", as the sling forces them together. The rope forces the "bottoms" together. This creates the bending force at twice the load (top load + bottom load). The ability to "shift side to side" is limited by the load applied and the fact they are symetrical. The worst thing about this bending is, it is applied in side loading between the locking mechanism (on the gate) and the spine of the other biner.
Want is the "danger" of having only 1 locker on a TR? To weak? Not "locked" secuely? I would be glad to read your documentation.
chris
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jumpingrock
Feb 28, 2005, 10:41 PM
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I'm going to have to side with the 2 locking biner's bad side of this argument. Though I will usually use two locking biners if I am using a screw gate and am happy with one if I am using an autolocker.
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reach
Feb 28, 2005, 10:50 PM
Post #28 of 49
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In reply to: One biner is fine (make it a locker), and two non-lockers are fine (make them opposite and opposed)
I'll support that statement. I use two non-lockers (that are opposite and opposed) because 1) it lessens the probobility of both biners rubbing against the rock and letting the rope slip through an open gate and 2) when the gates are opposite and opposed the gates (if both are open) make it very difficult for the rope to escape either biner.
I don't think it is a strength issue. We are tope roping here. A single biner can usaly handle a lead fall, why wouldn't it handle a day of top roping.
A single locker sould be OK because the gate is locked. If you take good care of your gear and make sure that you don't drop it from the top of the rock you should be able to climb on it for a life time.
If anyone does have documentation that says you should use more than two biners at a tope rope I would like to see it so that I can change my own practices to whatever is the standard. This stuff is changing all th time.
-Be Safe!
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chriss
Feb 28, 2005, 11:37 PM
Post #29 of 49
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In reply to: I'm going to have to side with the 2 locking biner's bad side of this argument. Though I will usually use two locking biners if I am using a screw gate and am happy with one if I am using an autolocker.
Please note that, I am not saying using 2 lockers is bad.
I am saying don't use any carabiner in a manner that creates a bending force on it.
The question was asked about the usage of 2 locking biners and the issue of the locking mechanisms creating a problem.
If there is no interference with any part of the carabiner and any other items (rock, another biner, rope, sling, bird, tree root, etc.), then feel free to use as many as you need to feel safe. BUT, if the carabiner is bent over the edge of a rock, a root, or even another carabiner then it will be weakened. If this bending is focused on the gate, even worse.
chris
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mtman
Mar 1, 2005, 12:30 AM
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the main problem with pear biners is that they can be cross loaded vary easily due to the large gate opening, and cross loading is very bad as i am sure you know. so use a different type of biner.
it is safe to use a single LOCKING biner for the power point (that is locked of course) but you will have more rope drag than if you use 2 biners.
the only time you NEED use two biners is with 2 non lockers and they have to be opposite and opposed. but to reduce rope drag you can use a locker and non locker opposite and opposed (incase the rubbing between the biners un locks the locker you still have a safe system)
hope that helps
mtman
i would like to see the documentation that says that one locker for top rope is unsafe. i was taught that one locker is acceptable by olympic mountain rescue.
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lumineferusother
Jul 5, 2005, 5:40 AM
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In reply to: “Many climbers do not realize that pear-shaped carabiners should only be used in belay-rappel situations. A wide, pear shape is ideal for use in conjunction with a plate-style device. . . or a Munter hitch. . . . If the carabiner is loaded on the spine side of the major axis, it will meet the major axis rated strength. But, if the carabiner is loaded on the gate side of the major axis, you can expect it to fail at half the rated strength. We have tested all major brands and none of the pear-shaped carabiners will even come close to meeting their rated strength when tested on the gate side of the major axis. These carabiners were designed to be used only in conjunction with a plate-style belay device. . . or with a Munter hitch. For clipping into belay station and building anchors, always use a ‘D’ style carabiner. . . . The ‘D’ shape makes loading the gate side of the major axis almost impossible.”
In my rope rescue class the use of Locking D's vs. Pears was stressed to us when setting up either personal or rescue systems where your loads consists of possibly a rescuer, a victim, and any other associated equipment. I'm only a beginner when it comes to recreational climbing but I highly doubt that the forces which occur in normal top roping come anywhere close to adversely affecting the strength of the biner.
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vegastradguy
Jul 5, 2005, 6:09 AM
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wow, i'm shocked at the number of people who really overkill their TR anchors.
i mean, if you want to beef it up, that's cool, but i know my multipitch anchors are tried and true and see no reason not to use the same logic on a TR anchor. this means non-lockers on all anchor points and a single locker on the power point. (although, depending on my mood, i may put a second locker on power point).
of course, if its a pair of bolts, my TR anchor consists of a pair of draws (gates opposite and opposed, of course).
edited to add: of course, i TR about 3 times a year, so take my comment with a grain of salt...
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billcoe_
Jul 6, 2005, 4:20 AM
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In reply to: wow, i'm shocked at the number of people who really overkill their TR anchors.
Come out with me, when I go strictly TR, you'll see 2 (two) 1/2" stock STEEL lockers rated to 50KN each. Overkill is a small word here!
Mostly I use steel so that my rope (and hands) stays clean and aluminum free. I use a steel locker and a steel Ushba belay device as well. The belay device looks homemade, but Ushba claims they were not able to break one on their testing machine, using a steel biner rated to 50kn, the biner would break first.
Clean rope good.
Also, every rope mfg will tell you that a larger radius surface is better than smaller, and that TR will wear your rope faster than leading and climbing regular style. Flat out: 2 big beefy biners are better for your rope.
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jt512
Jul 6, 2005, 10:13 PM
Post #34 of 49
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In reply to: I have always used 4 ovals opposing each other at the power point.
Why stop at 4?
-Jay
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jt512
Jul 6, 2005, 10:17 PM
Post #35 of 49
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In reply to: In reply to: I have always used 4 ovals opposing each other at the power point. Woah, hold on there. If you use more than two biners you actually make the system worse. One biner is fine (make it a locker), and two non-lockers are fine (make them opposite and opposed), but using three or more biners at the power point is a no-no. If you have three biners, the outside two are taking all the weight and are squeezing the inner biner and the inner biner will not be load bearing. I don't have the numbers offhand, but if you took a huge fall using three biners at the power point, you are essentially crushing the inner biner.
...which would result in what, microfractures?
FYI, three ovals is a pretty common setup. It's advantage over 2 is a wider load-bearing surface, which is easier on the rope. Or so it is claimed, anyway.
-Jay
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slobmonster
Jul 7, 2005, 3:02 AM
Post #36 of 49
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In reply to: i mean, if you want to beef it up, that's cool, but i know my multipitch anchors are tried and true and see no reason not to use the same logic on a TR anchor. this means non-lockers on all anchor points and a single locker on the power point. (although, depending on my mood, i may put a second locker on power point).
My own brand of logic --which seems to blend well with the TR crowd-- is that attaching yourself to an anchor on a longer climb, with a SINGLE locker, survives the redundancy test because you can fix anything strange that might happen. For example, if the gate becomes unlocked, or the 'biner gets loaded funny, all you have to do is reach up and deal with the problem.
However, as a TR setup requires you to be far below the 'biners in question, two are "better" because you can't simply reach up and fix the weird things that sometimes happen. We all know that loads and forces in TR settings tend to be very, very low... but the vigilance accrued in being s00per-anal about these anchors, as a beginner, may allow a climber to progress beyond his/her first frightening *omigod something weird happened* eventuality.
Jay, as always, thank you for the clarity I don't have the ability to utilize.
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carl12
Jul 7, 2005, 3:07 AM
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I've been using two OP Jake lockers for my powerpoints on TR. They are symetrical, so that when they are opposite and oppsed, the rope runs through a huge, wide, flat opening, which is why I chose to use them. Better for my rope. After reading this post, I took them out and set up a mock anchor on my couch. When the biners are hanging the right way, the the locking screws are resting against the spine of the other biner. Here's the questionable part: when there is tension on the system, the biners get pressed together, and the locking screw gets pressed tightly aginst the spine of the other very tightly. When the biners are unlocked and the biners oriented a certain way, it is actually enough to very slightly open both gates. I believe this is because of the offset gate opening direction. When the biners are switched around, the pressure pushes the gate into the closed position, not the open position.
It still dosn't seem like this would be too much of a concern while TRing. I always lock the biners, and I have not had them come unlocked. Any thoughts?
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vegastradguy
Jul 7, 2005, 4:12 AM
Post #38 of 49
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In reply to: However, as a TR setup requires you to be far below the 'biners in question, two are "better" because you can't simply reach up and fix the weird things that sometimes happen.
i generally use two lockers if i think this is a possibility. but, like i said above, i TR so rarely that I probably only set about three or four TR anchors a year...and one or two of them usually has two lockers on it. (the other two tend to be off a pair of bolts, so its just a pair of draws...)
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bill413
Jul 13, 2005, 2:49 PM
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I once had the experience of climbing up to an anchor consisting of a single locker - which had been dragged somewhat sideways across the rock by the path of the climb. This had unlocked the locking screw and, as my belayer started to take tesnion - caused the gate to open. Somewhat frighening to realize that my anchor system was an opened biner.
Ever since - I always use two biners at the power point.
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epoch
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Jul 13, 2005, 3:39 PM
Post #40 of 49
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Want to say that there are several people here that I would never climb with. Also that there are some scary things that I have read here.
With all ancors, irregardless of use or purpose, there should always be a redundnacy in the system. I would rather climb TR with the one who sets 4 locking ovals than with the one who only uses a single biner. Now, the forces generated while TRing are phenonimally smaller than lead climbing, if a 230 lbs ape were TRing and fell he should not generate mor than 4.08 KN. Now for those of you actually paying attention, let that number sit and ferment in your head. Wait a moment....................................... OK now go over and see that HMS beaner that you have in your closet. It will hold 20+KN wont it? Yeah. Now as long as you use 2 of the same biners, irregardless you should have redundancy, providing that you are anchored to two placements. Does it really matter? Just please do it safe. The forces generated Top Roping should never be enough for hardware failure.
Back to the shape of the biner..... Just make sure that there are 2 lockers at the rope end of the system.
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bluenose
Jul 13, 2005, 5:03 PM
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Seeing as this thread is still alive...I'll chime in.
For my TR anchors I have had to extend them to the edge of the cliff. All the biners that I cannot see, from the power point on down, while climbing or at least check near the top are always a pair of D lockers, opposed. The screw gates are past the opposed lockers' spine so there is no chance of interference. I keep the pears and HMSs for use in their appropriate purposes.
The biners over the edge of the cliff are, usually regular gate ovals, opposed. I can see them and adjust if needed at the top of the climb.
I have, in my short time climbing, seen biners do odd things already. Things that I wouldn't normally have expected. Opposed ovals have somehow rotated and are no longer opposed. I had a locker on my harness open and come off between clipping it, reaching for another piece of gear and reaching back to lock it.
Now that I know odd stuff can happen I am more inclinded to use equipment as recommeded by the designers or manufacturers. Usually, they have good reason behind their designs and intended usage.
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el_jerko
Jul 16, 2005, 6:29 PM
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A very basic priciple of anchor building is that everything needs to be redundant. A single biner at the power point is not redundant. All ths stuff a just read about one being better because two don't fit together perfectly or because it is an alpine climb or whatever is uh... stupid.
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curt
Jul 16, 2005, 7:06 PM
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In reply to: In reply to: One biner is fine (make it a locker), and two non-lockers are fine (make them opposite and opposed) I'll support that statement.
Indeed, that is the correct answer--but I notice (as usual around here) the discussion continues on. :lol:
Curt
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tweek
Jul 16, 2005, 8:37 PM
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In reply to: In reply to: In reply to: One biner is fine (make it a locker), and two non-lockers are fine (make them opposite and opposed) I'll support that statement. Indeed, that is the correct answer--but I notice (as usual around here) the discussion continues on. :lol: Curt
The discussion continues since people keep posting that one locker at the power point is acceptable in the beginners forum....
The answer, contrary to what some have said is... redundancy. Two biners, be them locking or not, are the minimum for top roping.
The argument among experiened climbers as to whether they use one or two for their anchors is irrelivent. More experienced climbers *should* be adept at recognizing an anchor biner that is going to be stressed over an edge or moved into a compromising position. Beginning climbers do not always have this forsight.
So Beginners (and anyone I climb with, regardless of experience) Two biners at the anchor point for a top rope is the minimum and "correct" answer. If you have two, even if they both unlock or are stressed against each other, you still have two. The forces involved are not that high that you will break them but it takes very little force to unlock and unclip a single locker.
I mean no offense to others who have posted that one is OK, but I stess that this is the beginners forum and safety should be the main thing tought here.
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qulith
Jul 16, 2005, 8:40 PM
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In reply to: A very basic priciple of anchor building is that everything needs to be redundant. A single biner at the power point is not redundant. All ths stuff a just read about one being better because two don't fit together perfectly or because it is an alpine climb or whatever is uh... stupid.
Uh huh.....
How about you rope running through your anchor...is that redundant.
Or this:
http://www.rei.com/product/47665532.htm?
Is the point where you attach the power point carabiner redundant?
As kobaz said:
In reply to: One biner is fine (make it a locker), and two non-lockers are fine (make them opposite and opposed)
As long as you set your TR so you are not loading the locking biner over an edge it is just as stronger as the rest of the single points of failure in the system (rope, harness, stupid belayer, belay biner).
When referring to redundancy in an anchor, it is referring to multiple unreliable anchor points if one blows.
But no one gives a rats ass what I say, so set up you TR and redundant as you want, better to be overly cautious when you are unsure, then to make assumptions.
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curt
Jul 16, 2005, 9:23 PM
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In reply to: In reply to: In reply to: In reply to: One biner is fine (make it a locker), and two non-lockers are fine (make them opposite and opposed) I'll support that statement. Indeed, that is the correct answer--but I notice (as usual around here) the discussion continues on. :lol: Curt The discussion continues since people keep posting that one locker at the power point is acceptable in the beginners forum.... The answer, contrary to what some have said is... redundancy. Two biners, be them locking or not, are the minimum for top roping.
Unfortunately, like many others, you fail to understand the true meaning of "redundancy" as it relates to climbing anchors. However, you are certainly entitled to whatever opinion you care to have on this topic--no matter how misguided.
Curt
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tumblemark
Jul 17, 2005, 1:23 AM
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Well, since this is a beginners' forum . . .
What the various posters are trying to get at is security, not strength. Relatively little strength is required when TRing or belaying a second; a figure of 4 kN max on the anchor is about right. Any carabiner of any shape will have adequate strength. There are important distinctions between strength and security that are not always obvious. For example, a locking carabiner has the same strength with the gate locked or unlocked. Lesson: when setting up a TR (or second belay) anchor, focus on security. These anchors don't have to bomb proof, they have to be goof proof. And accident proof. Generally, such features are supported by redundancy.
Here's what I'd recommend: Set up two confidence-inspiring placements (two bolts or trees would be ideal) and equalize them with a single runner in magic-X mode. Use a single locker (an HMS, if you like) at the X, small end on the rope. If you can't spare a big locker, go home. If you're TRing a sport route with a 2-bolt top anchor and use 2 draws, you'll rarely get equalization (shouldn't need it), but you will get redundancy. Using a runner will get you equalization, but not redundancy, so aim for redundancy by setting a third, independent placement and adding a second, non-loaded carabiner around the rope. Try for a setup that reduces the possibility of extension, but don't agonize because fall factors and anchor loading will always be low.
Circumstances will vary and dictate specific strategies, so experience is valuable. If one of your runner anchors is a sound tree, it might make sense to use it for the backup carabiner. Using one of two bolts for a backup runner doesn't provide complete redundancy, but it's better than depending on only one runner and biner.
Why only one locker at the power point? 1) Using two biners actually increases the rope friction (refs: Tyson/Clelland Illus Guide to Glacier Travel; Connally, The Mountaineering Handbook), 2) Two or more biners at the power point provide redundancy only for each other, but these are the least likely failure points. 3) One biner is plenty strong, and secure if locked. Anyhow, don't set up an anchor that could be scraped around by the climber (bad for the rope, too), tangled in brush, etc; adjust your runners or move the anchor. Using 2 draws atop a sport route...sure, clip through both draws. Use non-locker draws if necessary and if you don't climb above the anchors; otherwise, put the locker ends on the bolt hangers.
P.S. I can't agree with Metolius's assertion that HMS (pear-shaped) biners are somehow weaker when used at an anchor (and I use one of theirs), or maybe I don't understand how it's possible to "load a biner on its gate side" with the bollards of a test engine. Seems a D biner would actually be more susceptible to non-conventional loading when building anchors.
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el_jerko
Jul 17, 2005, 2:01 AM
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Qulith,
I am not saying this to be a blow hard know it all, but you are absolutely wrong. When speaking of redundancy in anchors it does not mean use more than one piece of gear, it means make everything redundant.
To answer your questions specifically, in a top-rope setup the rope is not considered part of the anchor. In situations where the rope is part of the anchor the thinking goes that if the load is going to break the rope it does not matter how strong the anchor is. I think of the rope as two parts, core and sheath and therefore it is inherently redundant. This might be total BS, but it makes me feel better.
I have never actually seen an “alpine equalizer” but from the picture the power point appears to be redundant in that it looks to be two pieces of webbing stitched together. I am not so sure about the rest of the rig, it looks like if you were to cut one of the loops the whole thing would unravel. If I were using that thing I would tie a knot in it just above the power point, then it would be redundant.
Whether or not you are loading the power point biner properly or not has nothing to do with it, a single biner is NOT redundant. If that biner fails, the anchor fails. If you have a setup where any single piece of the anchor fails the whole anchor fails, it simply is not a redundant system.
Redundancy in anchors is a philosophy. If you do not subscribe to it that is your prerogative. Alpine climbers have a different philosophy. They think they are better off going fast and carrying as little gear as possible, but an awful lot of them are killed climbing so I personally don’t pay much attention to what they do.
I also take issue with the general theme of this thread that top-rope anchors are not as important because they do not as receive high forces. This is exactly the wrong way to look at things. The difference between a top-rope anchor and most other climbing anchors is that you know damn well you are going use it and that your very life is going to depend on it. Not only that, you are most likelygoing to weight it over and providng opportunities for pieces of pro and biners to shift, and slings to saw through. Top-rope anchors should be constructed with the greatest care and redundancy, not the least.
-end of serman, climbing down off soap box...
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j_ung
Jul 17, 2005, 3:16 AM
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Funny thread.
In reply to: Top-rope anchors should be constructed with the greatest care and redundancy, not the least.
I agree.
One biner is plenty strong, but if I can't be right next to the power point at all times to make sure the biner isn't crossloaded or levered over an edge, then I want two of them there. (IMO, that's the difference between using one biner on multi-pitch anchors and one biner on TR anchors.)
More than once, I've climbed to a TR anchor and found the powerpoint biners to be in a different orientation then I left them. In each case I was relieved to have two of them.
And BTW...
In reply to: I don't have the numbers offhand, but if you took a huge fall using three biners at the power point, you are essentially crushing the inner biner.
That sounds ridiculous.
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