Worn Anchors...

[Ascentionist]

I remember reading a great story about TM Herbert, it might have been in one of John Long's books about one historic route where he was using a swami belt for a harness. Around the middle of the length of 2 inch webbing was a loop of masking tape. Herbert assumed it was marking the middle of the roll or something of that nature and paid it little heed.

He tied in, led the route as best I can remember to a ledge or top out and afterward after taking the swami off discovered that the tape was infact holding two ends of two pieces of webbing together, not marking the middle of a solid piece as he had believed.

Pilot error that did not end in tragedy...

[kato]

funny how the grooves make the anchors stronger

The grooves don't make the anchor stronger, they just direct the load onto the strongest part of the anchor. The non-grooved anchor allows the rope to slide out and gain better leverage against the most stressed part of the anchor.

[pkananen]

how much new hardware do you guys donate to the cliffs? just curious since you seem to be clear on what you want to clip, do you actually support that or just expect the crag gods to supply it for you ?

+1

Well, for the record, I have yet to run across any biners that had both a gate that wouldn't close and large rope wear grooves. Then again, I don't really climb many routes with fixed gear. I always carry extra quicklinks that I can use for replacement if I need.

[Ascentionist]

Speaking of quicklinks, I once saw (on a route in RRG, maybe Creature Feature or Lord of the Flies) where someone had placed shiney new quicklinks on old deeply worn quicklinks. Instead of removing the old ones or placing them higher directly into unworn links or the chain they dropped them in the grooves and called them good.

Of course I moved them, but didn't understand the rationale behind that. It would slow the wear in the already damaged links, but not improve the overall strength, and perhaps give the illusion of safety for those that didn't see the grooves under the shiney new links.

[512OW]

how much new hardware do you guys donate to the cliffs? just curious since you seem to be clear on what you want to clip, do you actually support that or just expect the crag gods to supply it for you ?

+1

Well, for the record, I have yet to run across any biners that had both a gate that wouldn't close and large rope wear grooves. Then again, I don't really climb many routes with fixed gear. I always carry extra quicklinks that I can use for replacement if I need.

Climb at the Lode... you'll see em. Well... maybe not. Most of them (I think) have been replaced in the last year.

[absolutsugarsmurf]

I've read Kolin's blog for a couple of years. From him and a few of guys on rc.com, Malcom Daily(MDaily, Richard Goldstone(rgold) and and Jim Ewing(sterlingjim) you can learn a lot about the physics principles applied to climbing scenarios. These guys are really looking out for us all.

The worn shuts in the BD test failed at about 11kN, the new shuts at about 6.6kN (if you're surprised at these low numbers just remember that these are open style shuts, not closed hanger-style anchors that are typically found in the Red). As kato pointed out, this wasn't actually due to a higher "strength" of the worn shuts, but rather in their ability to properly maintain the rope position relative to the spine of the shut throughout the loading cycle. This distinction is very, very important. Like carabiners, the shuts are strongest along the spine and weakest when loaded angularly. If Kolin had been able to mantain the rope position perfectly along the spine of the new shut they would have obviously been stronger than the worn shuts. So why when we buy shuts aren't they pre-groved to mantain rope-position along the spine? That should be obvious. The mechanism of failure of open shuts is not due to high dynamic forces, but rather low static force loads causing the opening of the already worn shuts. This could obviously never happen on new shuts, only worn shuts, just more worn than the shuts in the BD tests.

That said, I have to comment on Kolin's interpritation of his own data. The intended function of cold shuts, or any anchor, at the terminus of a climb is to lower or rappel off of, in a predominately static manner. Since the static force applied to an anchor by someone lowering is equal to the climbers weight plus the belayers weight minus frictional losses, a standard lowering scenario only might produce , at most, 2Kn at the anchors, of which there are two sharing the load. So as long as the system can hold more than 2Kn it's good. And new shuts will. Worn shuts might not, it depends on how worn. You're not going to be able to measure that in situ. All Kolin's data tells us is that a un-groved shut will deform under a lower load than a worn shut of the same material thickness after that shut has been worn. That is, a shut that is made of 1cm thick stock will deform before a shut that was made of 2 cm thick and has been worn down in a grove to 1cm thick.

To say that rope groved anchors are stronger is a false conclusion, and I think a dangerous statement to make on the BD website. Also dangerous is to state that the greatest danger of worn shuts it rope sheath damage. Moral of the story is to keep replacing worn anchors and keep using quick draws to TR on.

[Evan]

funny how the grooves make the anchors stronger

The grooves don't make the anchor stronger, they just direct the load onto the strongest part of the anchor. The non-grooved anchor allows the rope to slide out and gain better leverage against the most stressed part of the anchor.

I buy this rationale but overall I am not convinced by the way the test was set up. They should test the new and old shuts with the rope not in the strongest part (i.e. not in the groove) and see what happens. Also, it looks like they are not even testing the same type of anchors.

Did anyone see those biners that came out a while ago with a little roller for the rope where the groove would develop? Need a picture of it. Maybe it was not as dumb as it looked.

[512OW]

funny how the grooves make the anchors stronger

The grooves don't make the anchor stronger, they just direct the load onto the strongest part of the anchor. The non-grooved anchor allows the rope to slide out and gain better leverage against the most stressed part of the anchor.

I buy this rationale but overall I am not convinced by the way the test was set up. They should test the new and old shuts with the rope not in the strongest part (i.e. not in the groove) and see what happens. Also, it looks like they are not even testing the same type of anchors.

Did anyone see those biners that came out a while ago with a little roller for the rope where the groove would develop? Need a picture of it. Maybe it was not as dumb as it looked.

How would you ever lower off of anchors without the rope in the groove? Shouldn't things be tested in a real world manner?

I've used one of those roller biners... they're cool. Just don't fall on one with a really light belayer. They seem to be great for toprope anchors, and I love to use it as the tram biner while cleaning steep routes.

[Lateralus]

smurf this was Kolin's conclusion


• Rope-grooved cold shuts keep the load in line with the strongest axis and therefore can withstand a higher load before deformation.

he also stated in the first paragraph

(I’m not going to get into the technicalities, pluses or minuses of different kinds of anchors and am not condoning anything in anyway—I’m just looking at only one style of cold shut, one test, two data points, just out of curiosity more than anything.)

I don't see how your incorrect interpretation of Kolin's test makes their website or climbing for that matter any more dangerous than it already is.

PS climbing is dangerous always was and always will be.

[absolutsugarsmurf]

I'm saying his testing was incomplete and because of that, his conclusion is innacurate. The shut he tested with grooves deformed under a larger load than the ungrooved shut, yes. But he failed to discuss the effects of the most important variable , the percentage of material removed from the groove. At some point, when you remove enough material, the grooved shut will deform before the ungrooved shut, despite the loading direction effect. At what point is this? 50% grooved, 75% grooved, 10% grooved? Since you obviously can't measure this while climbing and is also material and design specific, the only safe procaution is to replace grooved anchors. BD stating on their website that grooved anchors are necessarily stronger than non-grooved anchors could easily cause people to not critically evaulate the condition of worn anchors, and instead just remember "well bd said that grooved anchors are stronger than non-grooved". That to me is dangerous. Made more so by the fact that his conclusions are notated by a bullet and seperated from the body of the text so as to make them easy to pick out, while his testing qualifications are not.

PS Thanks for the reminder that climbing is dangerous. Very insightful. I guess we should never seek to improve the safety of our equipment, information, or techniques, because shit, climbing is dangerous.