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Trentw
Aug 21, 2007, 6:52 AM
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What are the issues? What testing has been done?
From what I have read so far:
1. They unclip easier, compared to using a sling
2. The BD carabiner instructions doesn't warn against it
3. Shock loading of two biners causes them to be severely weakened (testing?)
4. Clipping more then two biners into another biner can cause triaxial loading
5. Triaxial loading can serverly weaken the biner (testing?)
6. The BD carabiner instructions warn against triaxial loading
Are there any other reasons why I should or shouldn't connect two carabiners together? Can anyone confirm any of the points above with studies and testing info?
I've searched rc.com/google/wikipedia but couldn't find any useful info. Just a lot of anecdotal info. So please no responses like "I used these for years and haven't died yet", or "lighting will fall from the sky and zap you dead if two carabiners ever touch each other". Thanks guys.
Trent.
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flyingsherpa
Aug 21, 2007, 8:11 AM
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Do you really need another reason?
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Trentw
Aug 21, 2007, 8:19 AM
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Hmmm, its not about what I need flyingsherpa, I just want to know the details on how these things work. Even if some of my above mentioned points are true, I can eliminate some of those risks.
Why should I be ignorant of other risks?
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flint
Aug 21, 2007, 9:12 AM
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Trentw wrote: What are the issues? What testing has been done? From what I have read so far: 1. They unclip easier, compared to using a sling I've searched rc.com/google/wikipedia but couldn't find any useful info. Just a lot of anecdotal info. So please no responses like "I used these for years and haven't died yet", or "lighting will fall from the sky and zap you dead if two carabiners ever touch each other". Thanks guys. Trent.
I prefer my biners to stay clipped....... I guess it is a personal preference.
And lighting in this situation comes from the climbing gods. To prevent this, I have never seen a boulderer with two biners anywhere, but then again, the climbing gods don't like to hunt that low on the totem pole.
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Trentw
Aug 21, 2007, 9:38 AM
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Thanks flint for some useless info. I can say useless stuff too: Six pink helicopters don't eat grass.
I personally can't see why carabiners unclip from each other easier then with slings. Even if they did, a simple control measure against that would be to use screw locking biners. Surprise surprise!
I hope the signal to noise ratio gets better, or am I being to optimistic?
Trent
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flint
Aug 21, 2007, 10:11 AM
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Trentw wrote: Thanks flint for some useless info. I can say useless stuff too: Six pink helicopters don't eat grass. I personally can't see why carabiners unclip from each other easier then with slings. Even if they did, a simple control measure against that would be to use screw locking biners. Surprise surprise! I hope the signal to noise ratio gets better, or am I being to optimistic? Trent
Take two biners and clip them together, and then play with them. Twist them, pull them, whatever. You will see how easy they can come undone. Now try the same exercise with a biner on a sling connected to another biner, magically, the sling is much more secure.
Yes, using a locker would prevent this, but in most cases, and I am not speaking for aid climbing due to my severe lack of knowledge, using a locker is more time consuming and not as effective. Think extending a sport draw using another sport draw, or putting a draw on a cam which has a racking biner.
Please don't come back saying the twisting action of these biners would never happen in real life, I have seconded on routes were the rope has clipped into the pro side biner, and in doing so, clipper the other biner to it as well.
You just never know, so the best control measure is to use a sling. Or, if you have 12 lockers, and extra time, go for it. Honestly, people probably clip biner to biner all the time, I personally, along with the agreement of many others, think this is a bad habit.
Pink helicopters are vegetarians. Brown helicopters drink Guinness. Just adding to the noise.
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Trentw
Aug 21, 2007, 10:33 AM
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Thanks for the more detailed reply.
In reply to: Take two biners and clip them together, and then play with them. Twist them, pull them, whatever...
I tried that little experiment. For two minutes I flung two connected quickdraws around, pretty harshly, and they never disconnected. I tried the same with just a sling, and same results.
For the next experiment, I tried very deliberately to unclip the sling from the biner. It was pretty easy. The funny thing is, when I tried the same with biner to biner, sometimes when one would unclip and the other would clip back in!
I'm not sure if my experiments prove anything. I was actually hoping for something more sophisticated then Trents Home Experiments.
In reply to: Yes, using a locker would prevent this, but in most cases, and I am not speaking for aid climbing due to my severe lack of knowledge, using a locker is more time consuming and not as effective...
I have deliberately not gone into uses of these systems as to avoid confusion. I just want to understand the dynamics of biner to biner action first, then let these findings influence how I use them.
Trent
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swede
Aug 21, 2007, 10:53 AM
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I canīt say thar I have the answer. Anyhow - two carabiners will mean there are two gates which could be forced open. And due to the natural orientation of the carabiners a greater chance that one will be forced open.
I donīt think you will notice any difference by just flinging them around. Try loading them and when having them move around on an uneven surface (cliff wall).
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Trentw
Aug 21, 2007, 11:12 AM
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In reply to: And due to the natural orientation of the carabiners a greater chance that one will be forced open.
Oh yes. I can see that. Well I think the point of carabiners unclipping from each other is covered well, how about the other points?
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swede
Aug 21, 2007, 11:37 AM
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Well, if somebody KNEW the reasons it would be better than me just using my knowledge in mechanics.
Shockloading: If we are talking of shockloading as for anchors because carabiners are non-dynamic my answer would be that a sling is also non-dynamic (enough to matter).
But if we are talking of two round edges against each other meaning a very little surface contact there is a "problem". The loading will get very high and you might theoretically get shearing. In practice I would be very surpriced if you got shearing, but I would expect a visual dent in the carabiners. Depending on the size this dent will weaken the carabiner and might even have sharp edges damaging soft materials like slings. I would retire carabiners with a more than negligible dent, but that would probably only happen after a long fall with high fallfactor.
Triaxial loading: Not good at all. People not used to mechanic calculations does not really understand how bad this can be. You will find threads dealing with the american death triangle with nice drawings. Please remember that most carabiners are built to take the load along the side with no gate.
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theguy
Aug 21, 2007, 12:01 PM
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swede wrote: But if we are talking of two round edges against each other meaning a very little surface contact there is a "problem". The loading will get very high and you might theoretically get shearing...but I would expect a visual dent in the carabiners. Depending on the size this dent will weaken the carabiner
Wouldn't the same be true of carabiners through a bolt-hanger or a nut wire? I haven't seen these uses described as an issue.
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swede
Aug 21, 2007, 12:19 PM
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theguy wrote: swede wrote: But if we are talking of two round edges against each other meaning a very little surface contact there is a "problem". The loading will get very high and you might theoretically get shearing...but I would expect a visual dent in the carabiners. Depending on the size this dent will weaken the carabiner Wouldn't the same be true of carabiners through a bolt-hanger or a nut wire? I haven't seen these uses described as an issue.
That is why I say "problem" - I do not see this as a major problem. However, there are recommendations for always having the same carabiner in contact with the bolt-hanger (and the other one for the rope) and also for not using slings which are not wide enough. If this is due to tests/ real experiences or just a safety measure based on how to conduct safety work - I donīt know.
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ja1484
Aug 21, 2007, 12:19 PM
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Trentw wrote: What are the issues? What testing has been done? From what I have read so far: 1. They unclip easier, compared to using a sling 2. The BD carabiner instructions doesn't warn against it 3. Shock loading of two biners causes them to be severely weakened (testing?) 4. Clipping more then two biners into another biner can cause triaxial loading 5. Triaxial loading can serverly weaken the biner (testing?) 6. The BD carabiner instructions warn against triaxial loading Are there any other reasons why I should or shouldn't connect two carabiners together? Can anyone confirm any of the points above with studies and testing info? I've searched rc.com/google/wikipedia but couldn't find any useful info. Just a lot of anecdotal info. So please no responses like "I used these for years and haven't died yet", or "lighting will fall from the sky and zap you dead if two carabiners ever touch each other". Thanks guys. Trent.
You'd be surprised how much "gospel" in climbing is based on anecdotes and hearsay. For example, it's clear from your post above that you believe shock loading actually happens. In a properly set up rope safety system for rock climbing, it doesn't.
Bottom line: Do what the manufacturer says when using their equipment, heed their warnings, and use common sense. The rest of it is mostly moot.
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binrat
Aug 21, 2007, 12:28 PM
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I have never seen this in a climbing situation, but have read a paper that deals with this in a rescue situation. if you want it try looking in www.sarbc.org
Binrat
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j_ung
Aug 21, 2007, 12:34 PM
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Trentw wrote: 1. They unclip easier, compared to using a sling 2. The BD carabiner instructions doesn't warn against it 3. Shock loading of two biners causes them to be severely weakened (testing?) 4. Clipping more then two biners into another biner can cause triaxial loading 5. Triaxial loading can serverly weaken the biner (testing?) 6. The BD carabiner instructions warn against triaxial loading
That about covers it. I've never heard number 3 and, considering all the biners on bolt hangers that haven't failed, I doubt it's true.
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reg
Aug 21, 2007, 12:44 PM
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i think, to a lesser degree - auto unclipping is a problem and to a greater degree - linear rotation (rotation along the long axis) which would break them quick. PROBABLY be ok in most situations. why are you asking?
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m2j1s
Aug 21, 2007, 2:01 PM
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I once took a class on building anchors, and one of the first things the instructor told us was not to clip two biners into eachother. He then clipped two together and twisted them really fast, and they unclipped. so i'm not exactly sure how you were twisting your biners, but i do know how easy it is for them to come undone because i saw it happen ;)
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Trentw
Aug 21, 2007, 2:04 PM
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In reply to: For example, it's clear from your post above that you believe shock loading actually happens. In a properly set up rope safety system for rock climbing, it doesn't.
Shock loading can happen easily, this can't be disputed. I doubt a lot that you can set up a rope safety system, that involves carabiner to carabiner, that avoids shock loading. My querry was: does shock loading of two carabiners significantely weaken them? Swede and J_ung both provide some insight to this question.
In reply to: Bottom line: Do what the manufacturer says when using their equipment, heed their warnings, and use common sense. The rest of it is mostly moot.
This is my problem, welcome to the thread :). The manufacturer doesn't have a problem of biner to biner action, but a lot of others do. OR are you saying biner to biner action is good because the manufacturers don't warn against it?
Also I would like to know how unsafe triaxial loading is. It is hard for manufacuturers to release specific info on this, apart from saying "don't do it". There are times when I may want to use a biner that may potentially triaxial load it, and I want to know how much danger I'm in.
Oh goody, someone saying just use common sense, lol.
Trent.
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Trentw
Aug 21, 2007, 2:10 PM
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In reply to: I've never heard number 3 and, considering all the biners on bolt hangers that haven't failed, I doubt it's true
Yeah, that was one of my arguments against that point.
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Trentw
Aug 21, 2007, 2:14 PM
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In reply to: one of the first things the instructor told us was not to clip two biners into eachother. He then clipped two together and twisted them really fast, and they unclipped.
Hey, I just did the same thing. Cool! I've gotten good enough I can make one carabiner unclip, and the other reclip back into it; in one quick twisting motion. I should run a Achor Building Class. This will be proof that carabiner to carabiner is safe.
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Basta916
Aug 21, 2007, 2:14 PM
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j_ung wrote: Trentw wrote: 1. They unclip easier, compared to using a sling 2. The BD carabiner instructions doesn't warn against it 3. Shock loading of two biners causes them to be severely weakened (testing?) 4. Clipping more then two biners into another biner can cause triaxial loading 5. Triaxial loading can serverly weaken the biner (testing?) 6. The BD carabiner instructions warn against triaxial loading That about covers it. I've never heard number 3 and, considering all the biners on bolt hangers that haven't failed, I doubt it's true.
thats what I wanna know...wouldnt biner on hanger be kind of same ( you know metal on metal ...blah ...blah....)
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Trentw
Aug 21, 2007, 2:17 PM
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Hi Binrat, I had a look at the site, but couldn't find any info on this subject.
Trent
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altelis
Aug 21, 2007, 2:20 PM
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dude, get your facts straight. Before the release of Jon Long's newest anchor book he and others did TONS of new testing and showed that shock loading is a myth. Do a search. The thread is eighty bijillion pages long, and also gave rise to the myriads of DIY new fangled anchors.
also, big wall climbing comes to mind. big wall anchors often entail a master point, to which a large locking carabiner is clipped. this biner then becomes the "new" master point to which everything else is clipped. This helps facilitate quick shuffling around of stuff (people, ledges, pigs, beer) at the anchor. Big wall climbing entails a LOT of weight and some pretty big loads if things go a little wrong.
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reg
Aug 21, 2007, 2:24 PM
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Trentw wrote: In reply to: For example, it's clear from your post above that you believe shock loading actually happens. In a properly set up rope safety system for rock climbing, it doesn't. Trentw wrote: Shock loading can happen easily, yeah but does not effect a well designed system as much as previously believed. Trentw wrote: . I doubt a lot that you can set up a rope safety system, that involves carabiner to carabiner, that avoids shock loading. do you climb? are you around other climbers when you climb? do you see a lot of "biner to biner" setups? Trentw wrote: My querry was: does shock loading of two carabiners significantely weaken them? no Trentw wrote: This is my problem, welcome to the thread :)........Oh goody, someone saying just use common sense, lol. don't be nasty Trentw wrote: Also I would like to know how unsafe triaxial loading is and I want to know how much danger I'm in.Trent. very - alot
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nepaclimber
Aug 21, 2007, 2:26 PM
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Trentw wrote: In reply to: one of the first things the instructor told us was not to clip two biners into eachother. He then clipped two together and twisted them really fast, and they unclipped. Hey, I just did the same thing. Cool! I've gotten good enough I can make one carabiner unclip, and the other reclip back into it; in one quick twisting motion. I should run a Achor Building Class. This will be proof that carabiner to carabiner is safe.
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