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HouseHippo


Sep 26, 2012, 12:59 PM
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Cordellette Anchor Question
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Hello everyone,

I plan on making the anchor shown below on any double bolted spots I run in to for top roping but just have a quick question. Why is the climbing rope feeding through two carabiners, isn't one enough or is there some safety reason that I'm missing?



Thanks!


jeepnphreak


Sep 26, 2012, 1:09 PM
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Re: [HouseHippo] Cordellette Anchor Question [In reply to]
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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.

if you have two locker why not make your outting just a bit safer.


csproul


Sep 26, 2012, 1:58 PM
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Re: [HouseHippo] Cordellette Anchor Question [In reply to]
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IMO, one is not enough. It is not a matter of strength. Ropes can pull across the gate and unclip or the gate can be pushed open by the rock. Two opposite and opposed biners prevent the rope from becoming unclipped. A single locker IMO is still not adequate. You are not there to attend a locker on a TR and cannot be assured that it hasn't come unlocked. Lockers can and do come unlocked. If this happens, you are now TRing on a single non-locked carabiner.


climbingaggie03


Sep 26, 2012, 2:15 PM
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Re: [HouseHippo] Cordellette Anchor Question [In reply to]
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I agree with csproul, I've seen people TR through one locker, but I've also seen lockers unlock themselves. Also as a nitpick, if I was going to set up an anchor like this, I'd have the gates on the biners that are on the bolts facing opposite directions.

To offer some unsolicited advice, if you're sport climbing, you can just put a quickdraw on each bolt (opposite and opposed) clip the rope to each one and call it good. The anchor you posted is perfectly acceptable and safe, but a bit of a pain to set up.


HouseHippo


Sep 26, 2012, 2:45 PM
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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! Smile


kennoyce


Sep 26, 2012, 3:00 PM
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HouseHippo wrote:
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! Smile

If you're clipping the rope to your harness with a biner you're doing it wrong. The rope should be tied directly to your harness through the tie in points, not clipped to your harness with a biner.


csproul


Sep 26, 2012, 3:12 PM
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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.


(This post was edited by csproul on Sep 26, 2012, 3:13 PM)


JaWiB


Sep 26, 2012, 3:20 PM
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Re: [csproul] Cordellette Anchor Question [In reply to]
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csproul wrote:
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.
Two carabiners is actually by the UIAA: http://theuiaa.org/...ope_by_karabiner.pdf


billcoe_


Sep 27, 2012, 11:34 AM
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Re: [jeepnphreak] Cordellette Anchor Question [In reply to]
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jeepnphreak wrote:
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.

Great post. On the money all the way. The thing I appreciate on top of all of that is that my rope will last longer. Not a bad thing.


knudenoggin


Sep 27, 2012, 11:34 AM
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jeepnphreak wrote:
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*


redlude97


Sep 27, 2012, 12:03 PM
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knudenoggin wrote:
jeepnphreak wrote:
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*
IIRC he said it was the same, since the total bend radius was the same for 1 vs. 2 carabiners


jeepnphreak


Sep 27, 2012, 12:51 PM
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knudenoggin wrote:
jeepnphreak wrote:
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*

It could be, but the difference is pretty minimal, I not a physicist at all so I not going to get in to calculating the exact numbers. In my experience having two carabineers seems to make a more pleasant rope experience. Whether it be a bit more friction and you are working less on your ATC end, or be it the ropes is running smoother through the anchor, whatever. The peace of mind in having the redundancy is the real reason.
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.


JimTitt


Sep 27, 2012, 1:03 PM
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redlude97 wrote:
knudenoggin wrote:
jeepnphreak wrote:
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*
IIRC he said it was the same, since the total bend radius was the same for 1 vs. 2 carabiners

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 IŽd be worrying about it in a top-roping context since its only about 10% more!


marc801


Sep 27, 2012, 1:09 PM
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jeepnphreak wrote:
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 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.


knudenoggin


Sep 27, 2012, 1:26 PM
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knudenoggin wrote:
jeepnphreak wrote:
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*

Actually, my memory growing, it wasn't >>rope<< but HMPE tape
that I tested, as that was what was at issue, i.p..
My thinking was that the sort of compressive *snowplowing* of
the material's surface in contact with the 'biner would be limited
in degree (a lesser degree at two points vs. greater at one!?),
and that the material wouldn't have to make the 180deg bend
all at once (more an issue w/rope than tape).

JimTitt wrote:
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 IŽd be worrying about it in a top-roping context since its only about 10% more!

I'm thinking that beyond two 'biners one will struggle to have any
sort of stable platform to postulate over! (and have way too many
" 'biners on hand", so to speak Tongue )

But, what's the quick rationale for the INcrease with 2 vs. 1 ?

[NB: It is NOT recommended to use 1 only in the TR, but as argued
above, two --frictional issues be darned. ]


*kN*


redlude97


Sep 27, 2012, 2:33 PM
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JimTitt wrote:
redlude97 wrote:
knudenoggin wrote:
jeepnphreak wrote:
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*
IIRC he said it was the same, since the total bend radius was the same for 1 vs. 2 carabiners

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 IŽd be worrying about it in a top-roping context since its only about 10% more!
Yep you are right it is Blush http://www.rockclimbing.com/...rum.cgi?post=2533857
JimTitt wrote:
YouŽve 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 AmontonŽs 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 doesnŽt 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


jeepnphreak


Sep 27, 2012, 9:01 PM
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marc801 wrote:
jeepnphreak wrote:
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 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.

Dude! you need to go into politics. thats is a great way of pulling what I said out of context. Look at the first part, than I said I BELIEVE. allthough it was a wrong statment I never said FACT.
Any why there you have it more friction over the two biner set up.


JimTitt


Sep 28, 2012, 3:30 AM
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Having struggled to pull the graph out from a calc. file the quality is not the best but hereŽs lifting an 80kg weight as a 2:1 purchase , 10mm rope with various numbers of karabiners. Tape IŽve 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.

Attachments: Karabinerefficiency.jpg (17.0 KB)


marc801


Sep 28, 2012, 9:35 AM
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JimTitt wrote:
Having struggled to pull the graph out from a calc. file the quality is not the best but hereŽs lifting an 80kg weight as a 2:1 purchase , 10mm rope with various numbers of karabiners. Tape IŽve 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.
What is the X axis?


redlude97


Sep 28, 2012, 11:43 AM
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JimTitt wrote:
redlude97 wrote:
knudenoggin wrote:
jeepnphreak wrote:
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*
IIRC he said it was the same, since the total bend radius was the same for 1 vs. 2 carabiners

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 IŽd be worrying about it in a top-roping context since its only about 10% more!
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?


JimTitt


Sep 28, 2012, 12:04 PM
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marc801 wrote:
JimTitt wrote:
Having struggled to pull the graph out from a calc. file the quality is not the best but hereŽs lifting an 80kg weight as a 2:1 purchase , 10mm rope with various numbers of karabiners. Tape IŽve 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.
What is the X axis?

Err, time.
ItŽs not relevant so it isnŽt on the graph. The plot is showing taking the load on the weight (the rising portion of the line) and then the force (or load) needed to pull it upwards (the horizontal lines). The plots are offset anyway to make it possible to see the different lines more clearly.
The horizontal portions of the plots are the important part!


JimTitt


Sep 28, 2012, 12:16 PM
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redlude97 wrote:
JimTitt wrote:
redlude97 wrote:
knudenoggin wrote:
jeepnphreak wrote:
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*
IIRC he said it was the same, since the total bend radius was the same for 1 vs. 2 carabiners

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 IŽd be worrying about it in a top-roping context since its only about 10% more!
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?

The wear on the rope should be worse with more karabiners since the increased resistance is due to increased flexing in the rope, on the karabiners themselves no idea at all!

However!
Its worth looking at a typical cordalette or whatever when the rope is running through the karabiner under load, you usually see that the Žbiner twists a bit and lets the rope touch the rock, if you use three (or more) karabiners side by side they bunch together and make a flat surface which lies nicely on the rock and this removes the rope rubbing problem. So more is better usually despite the theory!


chasetherabbit


Oct 4, 2012, 7:13 AM
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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.


(This post was edited by chasetherabbit on Oct 4, 2012, 7:34 AM)


JimTitt


Oct 4, 2012, 7:56 AM
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Why did you bother to sign up and reply?


chasetherabbit


Oct 4, 2012, 8:16 AM
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Seen a guy the other day at my local crag runnin around on ever sport route and slappin the same anchor to each one, leaving it tied and everything (not essentially a bad thing but it with sliding X's might as well re-tie to avoid the clutch effect) Having other people TR from them. Its dangerous, and i guess after seeing that and then seeing this on google anchor images, i felt i should say something. Did come off a bit arrogant I'm sure but safety is what were all looking for. Plus... this site is pretty cool now that I'm skimming through it.
I'm not a jerk i swear but someones gotta say somethin... especially after reading the reply that said it was "ok" to use one. -_-

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