Awesome, thanks for the replies everyone. I kind of assumed it was an added form of safety incase one of the carabiners were to become unlocked.

This sparks another question for me though. While I agree that if I have the extra carabiner, I may as well use it to make my trip just that much safer, but why is this trend only seen in anchors? I've seen pictures of people using two carabiners on their anchors countless times but I have never seen someone using two biners to lock the rope on to their harness. Using the same logic, the carabiner you use to lock your harness to your rope could just as, if not more easily, become unlocked while banging against the rock face during the ascend.

Is this not done because it just opens a whole new can of worms of redundancy or is there a difference between the two, because I just don't see it. Or perhaps people do use two carabiners to lock their harness to the rope and I just haven't seen it yet?

I apologize for my ignorance, I'm new and I would just like to sponge up as much information as possible that can make my climbs safer.

Thanks in advance!

In general, climbers don't often clip the rope into their harness with carabiners. They usually tie the rope on. However, there are times when people do clip the rope to their harnesses instead of tieing in. In these cases I'd definitely use two opposite and opposed carabiners just as I would with a TR anchor. It is true that you could use one locker, but I'm usually worrying about the climbing and not tending the carabiner. Since I do not have my attention focused on assuring that the carabiner remains locked, I prefer to have 2 carabiners.

As for the carabiner used to attach a belay device, in that case you are able to check that it remains locked and thus one is ok.

One biner is ok.
Two is better, stronger, redundant, and less friction on the rope.
It make the rope slide over a larger area, allowing the rope to run smoother while belaying and lowering.
also the way the biners are opposed makes the possibility of the gates comming un screwed, and the gates opening and the roping comming un cliped is almost impossible with two lockers.

One biner is ok.
Two is ... less friction on the rope.

That was my surmise, but in a thread on anchors Jim Titt
remarked that the doubled 'biners would increase friction,
and in some quick play with weights, rope, & 'biners, his point
seemed to be confirmed (but it was a slight difference).

*kN*

That was my surmise, but in a thread on anchors Jim Titt
remarked that the doubled 'biners would increase friction,
and in some quick play with weights, rope, & 'biners, his point
seemed to be confirmed (but it was a slight difference).

*kN*

IIRC he said it was the same, since the total bend radius was the same for 1 vs. 2 carabiners

I do believe that two carabineers are easer on the rope due to that the cerconfernce over two biners is 2x the rope is not flexing nearly as much.

That was my surmise, but in a thread on anchors Jim Titt
remarked that the doubled 'biners would increase friction,
and in some quick play with weights, rope, & 'biners, his point
seemed to be confirmed (but it was a slight difference).

*kN*

Your memory is failing you! The friction increases the more karabiners you add (the rate of increase slows after loads though, say about 5 or 6).
Not that I´d be worrying about it in a top-roping context since its only about 10% more!

Your memory is failing you! The friction increases the more karabiners you add (the rate of increase slows after loads though, say about 5 or 6).
Not that I´d be worrying about it in a top-roping context since its only about 10% more!

You´ve been reading too many papers by rescuers, if you read all the way to the bottom of what I have written to the bibliography you will find after the link the following:- "Stephen Attaway on friction and deriving Amonton´s capstan formula. Interesting mathematics but flawed."
That was a polite hint that it is completely wrong.

And if you (or he for that matter) bothered to do the experimentation or review bending theory or try some test calculation using the theory and match the results to known experience you (and he) would discover that Amontons capstan theory is inapplicable in a circumstance where the bending object has any moment of inertia.
He is wrong and you are wrong.

The radius of an object doesn´t change by placing another object beside the first, any child can see that. And the result of adding one part of a radius offset to another is that the rope bends, straightens and bends again so the work of bending has to be done twice increasing the resistance.

Get a spring balance, pull a rope with a weight over a karabiner and then add more karabiners. You will see the truth.


Jim

That is blatantly incorrect. With two biners, the rope contact surface is more closely modeled as a box with rounded edges, not a cylinder that is twice the diameter of a single biner, as your post implies.

Having struggled to pull the graph out from a calc. file the quality is not the best but here´s lifting an 80kg weight as a 2:1 purchase , 10mm rope with various numbers of karabiners. Tape I´ve never tested but it should be the same effect just less noticeable.
The steps as the load is taken up are from the powered winch used to lift the load.

Your memory is failing you! The friction increases the more karabiners you add (the rate of increase slows after loads though, say about 5 or 6).
Not that I´d be worrying about it in a top-roping context since its only about 10% more!

What is the X axis?

Based on this, what are the implications on carabiner wear? Does that mean that a 3 carabiner TR setup would produce more wear than a 2 or 1 carabiner TR anchor?

Saw this post and literally signed up to rockclimbing.com to reply to it. You are going to get someone hurt.
1: Conforming to one type of anchor on every double bolted anchor spot displays your inexperience. (As well as the carabiner question)
2: Your carabiner question. It is NOT okay to use only one carabiner at the powerpoint, even if it is a locker it can come undone. Always two carabiners opposite and opposed.
3: Cordelette anchor: Is it safe to say that every route you climb has absolutely no traverse? Falling anywhere off the rope line you positioned that anchor for will cause stress on one of the bolts. Studies show the cordelette anchor istelf can never achieve perfect equality. Depending on the route, it is usually safer to go with a sliding X, provided the bolts are perfect and theres no worry of extension... and a bit of other things that YOU should know about as the person doing anchors for someone. For example...
4: That pic you posted has carabiners on "RAP" rings...
Your ignorance will hurt someone, buy some anchor books, search the internet, take a class and speak with old rock climbing specialists then come back and say you've learned to be safe.
My apologies for coming off rude, but this is why people get hurt.

As for the rings, i was hinting upon him to look them up. I was hoping he would read things such as: Do not TR through rings as abrasive in rope abrades it. Aluminum holds 3,400 (rough) pounds new but what if he does that anchor to an abraded ring and falls. Theyre meant for "rappelling." Unless they're solid, no-wear stainless steel or titanium i would hope he had the knowledge to back it up.

Is everyone arguing about top rope anchors on two good bolta again?

Sure seems that way, this time with a righteous n00b adding in the "it must always be done this way" meme.

chasetherabbit, you seem to feel very comfortable providing "guidelines" to other climbers and pointing out the errors in their thinking. What is your experience level? How long have you been climbing? Please, tell us a little bit more about yourself so that I can understand where your wealth of knowledge comes from.

Youve never backed up sketchy bolts before in squamish?

Hold on a sec... where did i... its around here somewhere... aHA!!! Her it is. Your pedastel.

... i feel dumber having even talked to you. . . I said nothing about me.

I was not moaning about the set-up in the pic. 2nd post i said it was fine. I get mad when i see beginners looking at anchor pics and then goin climbing. Laugh all you want. Just tried to get someone to not become accustomed to one anchor. Theres more to it.

Redlude97, not all bolts are bomber. And if you send a beginner off to a crag of 50 sport routes with a pre-tied anchor you're an idiot. Do you suggest that this "beginner" disregard equality on double bolted sport routes?
Say, this beginner decides to go ahead to the local sport crag slapping in his same length cordelette at every 2 bolt anchor. Because nobody disagrees with him he assumes its okay. He doesnt check one of the bolts (that had been drilled improperly) and due to the weight he produces upon falling off the direction of pull he rips one bolt out. Sure, there is little to no extension in a cordelette set-up but does that make it okay? If you're gonna TR from a two-bolt anchor with why not just make it an equalette? Safer, long, no extension, and has a wide arc for traversing. (im just gonna stop writing about this here i dnt want to write a text-book)

If the bolts are bomber, a sliding X on a two bolt anchor is the best-known method. "It is better to dynamically equalize the load on the gear [bolts in this situation] in an effort to prevent failure than to anticipate failure and mitigate the consequence of extension." The extension is longer but according to studies done by John Long, Craig Conally and a member of Rock & Ice magazine, true shock loading with the sliding x cannot occur when there is dynamic rope in the system. Review pages 159-160 in "Climbing Anchors" by John Long and Bob gaines: "Granted, you avoid building anchors that could result in really long extension, but there's little cause to fear ordinary set-ups."

As for the rings, i was hinting upon him to look them up. I was hoping he would read things such as: Do not TR through rings as abrasive in rope abrades it. Aluminum holds 3,400 (rough) pounds new but what if he does that anchor to an abraded ring and falls. Theyre meant for "rappelling." Unless they're solid, no-wear stainless steel or titanium i would hope he had the knowledge to back it up.

I do not wish to pursue an argument but if you feel you need to make your opinion clearer please feel free to enlighten me.

I respectfully wish for this argument to end as everyone seems to be getting angry with me.

I wasn't trying to start a problem.

Saw this post and literally signed up to rockclimbing.com to reply to it. You are going to get someone hurt.
1: Conforming to one type of anchor on every double bolted anchor spot displays your inexperience.

1: I do not have a "go-to" for any type of anchor. I will say, however, that when it comes to bomber two bolt anchors i usually use a sliding X, or, if i need length but want no extension, i use the equalette. The cordelette I have used as well but in terms of equalization i prefer the equalette.

2: I never had a problem with the anchor above. I did mention (and the obvious reason people yelled at me) that the carabiners were clipped into rings and hinted to the OP to search more in depth on that. I can see how many misunderstood what i was trying to prove. I wasn't saying it was bad but i wanted the OP to see what rings were bad and learn about wear.

4: That pic you posted has carabiners on "RAP" rings...

3: I am not a know it all like many of you now think but i do wish for everyone to be safe and enjoy climbing.

I have actually given people anchor chains when they do a walk-around to set-up a top rope. (Not trying to look cool saying that)

4: I believe it is important still for the OP to read about direction of pull, fall forces and static loading before setting anchors. Equality is important and the cordelette even by looking at being pulled of its direction pulled proves its poor ability at maintaining equality. (Not saying never to do one)

5: I hope you all the best and safest of climbing and apologize for making anyone angry.