Fixe Anchor Failure

mattm wrote: ...Jim's tested 4mm stock (8mm hole) that meets EN-959 but he notes that customer resistance is an issue!

Again, see my Henry Ford quote....

slim wrote: as for the rope twisting. look at the locations of the contact surfaces on the top and bottom links/rings. they are 90 degrees out of phase. this is going to cause the rope to have drag at these locations and cause a corkscrewing motion as it passes through the anchor. the reason the single ring anchors are a problem is that the rings usually aren't parallel to each other. if the eyes of the hangers are horizontal, the rings can both be vertical and parallel to each other and perpendicular to the rope passing through between them. it also allows the contact surface of the rope to be at the inside (bottom) of both bends, which is where it should be to cause the rope to run slower at the INSIDE of the curve.

I'm sorry but your wrong on this one.

What twists the rope is when there are two ring for anchors set horizontally apart with a gap between the rings. Think two bolt/ring combinations set horizontally 6-12" apart so the rings don't touch. This while being a low material anchor twists the rope and also puts a CCW torque to the left hand bolt causing it to loosen at times.

The bolt/chain/ring combo that hangs as a vee with the rings touching does not twist the rope at all. It does used a lot of material and most of the time the only SS components are the bolt/hanger. The links and chain are almost always carbon steel. Not the the chain is weak but it does corroded and the link just becomes welded shut. In some instances this type of anchor is the best solution. On irregular surfaces or when one needs to clear a bulge.

The vertical type bolt/ring anchor uses the least amount of material that doesn't twist the rope. Plus it's easy to make it completely from SS hardware. The bolts don't need to be directly vertical either, actually is best if they are slightly apart. Think 6-8" vertically and 2-3" horizontally apart. Just enough afford that the lower ring can be pulled slightly sideways from the hanger.

NOTE when I say bolt/ring, what I mean it's a hanger that has a ring that hangs perpendicular to the rock. There are double ring hangers and single ring hangers that achieve this. The important thing is that the rings are perpendicular to the rock surface.

rocknice2 wrote: What twists the rope is when there are two ring for anchors set horizontally apart with a gap between the rings.

That is not the only way to cause twists. Several major crags such as Owens River Gorge use tow hooks as loweroffs. These tow hooks are essentially like the Fixe ring anchors in that they are placed horizontally with no flexibility, and they hold the rope perpendicular to the rock. I see people top rope off those things all the time without twisted ropes. I have also seen people lower off glue in eye bolts without twisted ropes, again placed horizontally.

On the other hand, running your rope through a link which is parallel with the rock will cause twists as I have witnessed many times. I have sat on an anchor and watched a dude TRing on the anchor twist the rope to crap as it moved through the anchor because the last link was parallel with the rock. This is common in a situation where the developer uses a standard bolt hanger and the developer only puts one quicklink on the hanger instead of two.

As far as the Fixe ring hangers go, the reason I believe they twist the rope while similar anchors are less likely to (e.g. glue ins, tow hooks, lower offs, cold shuts, ect.) is because when you are lowering off the ring, the ring closest to the belayer's side of the rope tends to rotate inward CCW toward the other hanger, while the hanger closest to the climber does not. This in essence mimics a ring that is parallel with the rock instead of perpendicular, thus twisting the crap out of the rope.

20 kN wrote: Despite numerous deaths of climbers bailing off single bolts, the UIAA's recommendation was a single bolt anchor? Seems hard to believe an organization committed to safety would recommend something that's well known to be a very poor choice, and expressed as such in just about every climbing book, forum, blog and instruction booklet made. It's damn near common sense that bailing off a single piece without backup poses significant risk.

They didn´t recommend one bolt, they recommended two bolts for multi-pitch belays which is subtly different.
The UIAA is a representative body, since a considerable number of the national federations have widespread use of single-bolt anchors there may be difficulties in getting two bolts approved in the standard.
As the bolt standard requires all anchors to be stronger than any load that can be imposed by a climber then requiring two for the lowest loaded bolt of all is illogical.

That numerous climbers have died from single anchor failure does not mean ANY have died from failure of correctly installed anchors manufactured to EN959. Climbing equipment standards are not designed purely on the basis of percieved or theoretical risk alone, the historic risk is also considered and compromises are made all the way through our equipment and until the actual risk from only installing one certified anchor becomes unnaceptable then their use is still reasonable. In sport climbing (which we are discussing) the climber ALWAYS has the possibility to create redundancy if they wish.

Jim Titt makes those small glue ins the CWCA is placing. I believe (Jim?) they are rated to 40 kn.

Everyone on here arguing against the French set up basing their argument on tradition, not what works. It is not stronger, it is not safer, and it is not a better system. It is simply what we were originally taught. We might as well not use gri gri's and live with the rule that the leader never falls.

20 kN wrote: As far as the Fixe ring hangers go, the reason I believe they twist the rope while similar anchors are less likely to (e.g. glue ins, tow hooks, lower offs, cold shuts, ect.) is because when you are lowering off the ring, the ring closest to the belayer's side of the rope tends to rotate inward CCW toward the other hanger, while the hanger closest to the climber does not. This in essence mimics a ring that is parallel with the rock instead of perpendicular, thus twisting the crap out of the rope.

Interesting that we have completely opposed experiences.

As noted above, Wave bolts and Twisted-Leg bolts are nearly the same size, you need a micrometer to tell the difference. Wave bolts just "look bigger" because they are super shiny.

As far as anchor orientation, my first reaction is "Who cares? At least they're not two 1/4" bolts with rusty Leepers." And the French system is way better than the single-giant-glue-in-bolt anchor which is common in some places in Europe - even though they may hold a truck, I've seen them really rusted and very worn (of course you'd probably need to wear more than 95% of the way through one of those huge bolts to actually get it to break).

The main argument against the French system is U.S. climber ignorance of how to use the system. Any anchor placed like that on an easier route is going to end up sprouting "equalizing" webbing and rings/links/biners within a few days.

The same concern - ignorance - can be an issue when using fat glue-in bolts at anchors. Some idiot is going to steal the links & rings since you can clearly rap straight off the glue-in bolts without damaging your rope. And of course people will top-rope off them too, and within a few years the bolts themselves will be showing rope grooves, and sooner or later everyone will be complaining about the sketchy anchors. That could also happen with the French system.

100% correct Greg. I use locktite so they would have to take a wrench to steal the stuff.

It took a few years for people to catch on to toproping on quickdraws, but now most climbers are taught that. Eventually most climbers will learn how to get down off a French style anchor without feeling they have to add equalization.

Greg Barnes wrote:As noted above, Wave bolts and Twisted-Leg bolts are nearly the same size, you need a micrometer to tell the difference. Wave bolts just "look bigger" because they are super shiny.

Interesting, I hadn't ever realized the difference in size was so little until mattm's post up-thread, but I do know that wave bolts do look bigger. I would have never guessed that the shininess of wave bolts is to blame.

As far as climbers needing training as a good reason not to use the French system, like everything, there would be a bit of a learning curve, but I don't really see that as a reason to keep using the current extra expensive "V" setup. I'm going to start placing French style anchors on my routes from now on except in the case of routes with easy lower-offs.

Sam Lightner, Jr. wrote:Jim Titt makes those small glue ins the CWCA is placing. I believe (Jim?) they are rated to 40 kn. Everyone on here arguing against the French set up basing their argument on tradition, not what works. It is not stronger, it is not safer, and it is not a better system. It is simply what we were originally taught. We might as well not use gri gri's and live with the rule that the leader never falls.

if you read the comments above, Jim states that the accident (where the anchor block pulled off) wouldn't have happened with a vertical system. How would this not happen with the French system? all of the climber's weight would be on the upper bolt (in the loose block).

rocknice2 wrote: I'm sorry but your wrong on this one. What twists the rope is when there are two ring for anchors set horizontally apart with a gap between the rings. Think two bolt/ring combinations set horizontally 6-12" apart so the rings don't touch. This while being a low material anchor twists the rope and also puts a CCW torque to the left hand bolt causing it to loosen at times. The bolt/chain/ring combo that hangs as a vee with the rings touching does not twist the rope at all. It does used a lot of material and most of the time the only SS components are the bolt/hanger. The links and chain are almost always carbon steel. Not the the chain is weak but it does corroded and the link just becomes welded shut. In some instances this type of anchor is the best solution. On irregular surfaces or when one needs to clear a bulge. The vertical type bolt/ring anchor uses the least amount of material that doesn't twist the rope. Plus it's easy to make it completely from SS hardware. The bolts don't need to be directly vertical either, actually is best if they are slightly apart. Think 6-8" vertically and 2-3" horizontally apart. Just enough afford that the lower ring can be pulled slightly sideways from the hanger. NOTE when I say bolt/ring, what I mean it's a hanger that has a ring that hangs perpendicular to the rock. There are double ring hangers and single ring hangers that achieve this. The important thing is that the rings are perpendicular to the rock surface.

It sounds like in the last couple sentences you are basically agreeing with what I said (?). Which doesn't really agree with what you said above (don't worry, I don't really agree with what you said above either). I agree w/ 20 kN on this one.

slim wrote: if you read the comments above, Jim states that the accident (where the anchor block pulled off) wouldn't have happened with a vertical system. How would this not happen with the French system? all of the climber's weight would be on the upper bolt (in the loose block).

The accident wouldn't have happened because the lower bolt would have been in the rock below the loose block, so when the loose block came off the climber would have fallen the 1 foot or so until the lower redundant bolt took the weight of the climber. You would however then have a block that is attached to the rope possibly flying towards either the climber or the belayer depending on how the rope was set up through the anchor.

slim wrote: It sounds like in the last couple sentences you are basically agreeing with what I said (?). Which doesn't really agree with what you said above (don't worry, I don't really agree with what you said above either). I agree w/ 20 kN on this one.

I agree with you and 20 kN on this one. The twisting happens because the two rings are not held perpendicular to the rock. Generally due to friction on the rock the two rings rotate inward so that they are not parallel to each other which puts twists in the rope. If two rings are free hanging but separated with nothing to make them turn from being parallel to each other they won't twist the rope.

Both of these anchor have rings that are perpendicular to the rock. One is a double ring, the other is a single ring.

If placed in a horizontal position they will twist the rope. This type of anchor is the worst.


If placed in a vertical orientation they do not twist the rope. In this photo the lower ring is not perpendicular to the rock. It's OK like this but it a different ring was used it would be better.


Now in some instances a vee anchor is the best solution.

rocknice2 wrote:Both of these anchor have rings that are perpendicular to the rock. One is a double ring, the other is a single ring. If placed in a horizontal position they will twist the rope. This type of anchor is the worst. If placed in a vertical orientation they do not twist the rope. In this photo the lower ring is not perpendicular to the rock. It's OK like this but it a different ring was used it would be better. Now in some instances a vee anchor is the best solution.

I don't think you have it quite right. Your second picture is more or less fine and will not induce much twisting in the rope. However, contrary to what some have said here, simply having a ring that hangs perpendicular when it is not loaded is not a good indication of whether it will twist the rope. The important information is knowing what orientation the rings end up in when the rope loads both anchors in tandem (and clearly this only applies for horizontally place anchors, because the vertical setup only loads one anchor). In the case of the single ring Fixe anchor, the two rings initially hang perpendicular (or largely so), but when they are loaded together, the two rings induce an inward force on each other -- via the rope -- that twists the orientation of each ring sharply. This sharp orientation shift causes the rope to have the the force of its load exerted asymmetrically across the surface of each ring. It is this asymmetric force on the rope that causes the twisting.

One of the keys to remedying this situation with a horizontal setup is to have chains extending downwards. Doing so lessens the inward force that twists the links and causes the asymmetric loading that twists the ropes. That is why your second and fourth pictures twist the rope far less than a single ring Fixe setup.

In the vertically oriented ("French style") anchor system, do the primary and backup have to be solid rings or links? Can each be a "ram horn" or quickie? I am asking because all the photos (so far) show the French style anchor system requiring the last person of the party to untie and thread the rope through at least one ring/link. A somewhat time consuming task which is also more error prone for the less experienced or well-travelled climber.

S. Neoh wrote:In the vertically oriented ("French style") anchor system, do the primary and backup have to be solid rings or links? Can each be a "ram horn" or quickie? I am asking because all the photos (so far) show the French style anchor system requiring the last person of the party to untie and thread the rope through at least one ring/link. A somewhat time consuming task which is also more error prone for the less experienced or well-travelled climber.

Yes (for the most part), this in my opinion is the main reason not to use the French style anchor. The issue is that if you have any type of quick clip style anchor and the top anchor were to fail, there is a high probability that the rope could become unclipped from the lower anchor due to the rope movement. About the only way to mitigate this risk would be to have some type of a locking biner on the lower bolt and to make sure it was locked at all times so that it could provide true redundancy.

J. Albers wrote: I don't think you have it quite right. Your second picture is more or less fine and will not induce much twisting in the rope. However, contrary to what some have said here, simply having a ring that hangs perpendicular when it is not loaded is not a good indication of whether it will twist the rope. The important information is knowing what orientation the rings end up in when the rope loads both anchors in tandem (and clearly this only applies for horizontally place anchors, because the vertical setup only loads one anchor). In the case of the single ring Fixe anchor, the two rings initially hang perpendicular (or largely so), but when they are loaded together, the two rings induce an inward force on each other -- via the rope -- that twists the orientation of each ring sharply. This sharp orientation shift causes the rope to have the the force of its load exerted asymmetrically across the surface of each ring. It is this asymmetric force on the rope that causes the twisting. One of the keys to remedying this situation with a horizontal setup is to have chains extending downwards. Doing so lessens the inward force that twists the links and causes the asymmetric loading that twists the ropes. That is why your second and fourth pictures twist the rope far less than a single ring Fixe setup.

And that's why most of the time the vertical orientated ring anchor "french style" is the preferred anchor. It's having a hard time gaining popularity this side of the Atlantic for some reason. Like the EDK took decades to gain acceptance.

Jim Titt wrote: In sport climbing (which we are discussing) the climber ALWAYS has the possibility to create redundancy if they wish.

How is someone supposed to create redundancy with a one bolt anchor while cleaning the route after the last climber? Use a prussik or put the GriGri on backwards so if they fall they whip onto a lower bolt? Yea, technically you can do that, but heck man we are talking about sport climbing, I bet 90% of sport climbers dont even know that trick. Even if they did, why take the risk of whipping like that just to save a single bolt at the anchor? Why risk taking a 30 footer (and likely breaking your legs if you're close to the deck) if the anchor pulls and you whip into the lower bolt?

The second bolt is not about strength, it's about redundancy. The same theory as to why you dont rap off a single cam. Bolts pull all the time, UIAA certified and all. I dont know what places you are visiting that all have single bolt anchors, but if you tried that in the USA at a major crag your lines would get chopped or retrobolted overnight, and for good reason.