I need some enlightenment on this. Why does the sliding X need redundancy? I'm going to assume you're talking about one arm of the X failing (the sling, not the piece) for whatever reason. I don't see this as a benefit or justification for using limiter knots as slings don't simply fail. Yeah sure you could say rockfall might cut one arm of the X but I suspect there'd be bigger problems if that were the case.

To me it seems like a solution where there is no problem thus not worth the effort (for the redundancy factor, not talking about extension here). Is there another "need" for redundancy in the X that I'm not seeing? Thanks.

d.

I believe you may not be considering the distinction between the climbing rope (dynamic) and sliding-x sling (considered to be static). The purpose of using limiter knots in a sliding-x is to limit the added length of a fall (the extension in the sliding-x) on static material. The static material contributes to the length of the fall (l), but not to the amount of dynamic rope available (r). The limiter knots reduce l and hence the fall factor, as I explained in my previous post. This is not my unique theory: virtually every knowledgeable poster on this thread will agree with the above. The disagreement pertains to added complexities.
.

I question the whole lot, for most belay anchors, myself. I don't buy the notion that every belay has to be equalized. I don't buy the notion that every sling has to be limited either. I can see using these things for specific scenarios, but I see no need for wide spread deployment.

Can you clarify this statement? Does this statement mean that sometimes you think equalization is useful and/or necessary and sometimes you think limiting is useful and/or necessary?

I need some enlightenment on this. Why does the sliding X need redundancy? I'm going to assume you're talking about one arm of the X failing (the sling, not the piece) for whatever reason. I don't see this as a benefit or justification for using limiter knots as slings don't simply fail. Yeah sure you could say rockfall might cut one arm of the X but I suspect there'd be bigger problems if that were the case.

To me it seems like a solution where there is no problem thus not worth the effort (for the redundancy factor, not talking about extension here). Is there another "need" for redundancy in the X that I'm not seeing? Thanks.

d.

What I object to is people passing off opinion as fact and suddenly the opinion becomes standard operating procedure and is never questioned.

I've no doubt you and lots of others can tie a knot in a sling lickety split. I also have no doubt that many MORE cannot do it quickly. And there is a select group, probably the largest of all, that ties and reties these things, at every single belay.

I think efficiency is entirely and I mean entirely overlooked in these discussions. So when someone passes off an opinion as fact I may from time to time ask for some, you know, proof.

Something entirely absent in this thread.

I need some enlightenment on this. Why does the sliding X need redundancy? I'm going to assume you're talking about one arm of the X failing (the sling, not the piece) for whatever reason. I don't see this as a benefit or justification for using limiter knots as slings don't simply fail. Yeah sure you could say rockfall might cut one arm of the X but I suspect there'd be bigger problems if that were the case.

To me it seems like a solution where there is no problem thus not worth the effort (for the redundancy factor, not talking about extension here). Is there another "need" for redundancy in the X that I'm not seeing? Thanks.

d.

Dlintz, ever spent any time on FA or early ascents in the desert? No, I didn't think so.

But come to think of it, all it takes is a little poor routefinding, even on well established routes. I once did an ascent of Wigs in Space in Zion. My partner followed the "logical" line and wound up in a rotten crack. He probably rained down over a ton of rock. I don't know which of us was more scared. But I'll tell you, with all those shards of rock bouncing off the rock and flying around, I'm damn glad I had some redundancy in the slingage that made up the anchor.

GO

I'm with you there 100%! But you're up against a mighty opponent - human nature itself. People love to pass along rumors and half-truths as if they were gospel. (Hmm, maybe that's where the gospels came from?)

Still, I'm with you on that fight. What I'm not down with, though, is that sometimes that broad brush of yours tars a bunch of innocent bystanders.


Yeah, maybe. Though I'm almost tempted to ask if *you* have empirical proof of all these gumbies running around tying themselves in knots (your own experience running into these gumbies is proof if you say you've actually seen such a thing). But I have a sneaking suspicion that you're tilting at windmills.

Because the only partners I've had that seem to always take too long to build an anchor are those who basically are one-trick-ponies, and get confused when the rock doesn't fit their scheme. Equally so with folks who just use the rope, or just use slings, or just use some crazy -ette method.


Okay, well here's my $.02. I've spoken to Jim at Sterling - a professional who really knows ropes, has professionally calibrated equipment, and the experience gained from using them regularly in his work. He conducted real empirical tests. And I've also spoken to Richard G (a mathematician) and Larry Hamilton (a statistician), who analyzed those tests.

My recollection (sadly, lousy at best, and this is going on three years ago) is that the limited extension in a standard over-the-shoulder runner creates zero to minimal additional force when it impacts on the next piece in line. In fact, there is some evidence that the force felt by the second piece may in some cases even be slightly *less* than the sum of the force on the two pieces before the first one blew. The reason for this is presumably because in between the first piece blowing and the second one being impacted, the extension allows the rope to relax somewhat, decreasing the overall force on the anchor.

In other words, the only strong hard evidence I know of says that in the limited scenario that was tested for, minor extension is not a serious concern.

That's not to say that limiter knots *never* provide a benefit. I think I've given two cases where they do.

GO

If the leader takes a fall directly onto the anchor, it's a factor-2 fall, whether one arm of the anchor fails or not. So, if one arm blows, the peak tension in the climber's side of the rope should not be greater than if the arm had not blown. But then there's the belayer. If an arm of the anchor fails, the belayer is taking a fall, too, and the peak tension in his side of the rope will be an increasing function of his fall factor, which in turn is an increasing function of the amount of the extension. And the force on the anchor is, of course, the sum of these two tensions.

I don't recall the specifics of the Sterling tests, but I don't think that the methodology included a "belayer effect."

Jay

Come on in, and let's spend 7 pages in pointless, irrelevant, and above all, empirically unfounded armchair speculation about the physics of climbing anchors.

Equalization is CLEARLY a good thing eh? Should be easy tpo quote a study with some test numbers then? Ditto extension.

I question the whole lot, for most belay anchors, myself. I don't buy the notion that every belay has to be equalized. I don't buy the notion that every sling has to be limited either. I can see using these things for specific scenarios, but I see no need for wide spread deployment.

I ask for facts and lo, there aren't any except for napkin calcs.

My position is not extreme. I am QUESTION convention al wisdom, a convention that has been in place less than a decade mind you. A convention backed with precious few facts and no studies at all, apparently.

In fact, there is some evidence that the force felt by the second piece may in some cases even be slightly *less* than the sum of the force on the two pieces before the first one blew. The reason for this is presumably because in between the first piece blowing and the second one being impacted, the extension allows the rope to relax somewhat, decreasing the overall force on the anchor.

If you spent a lot of time on top rope cleaning a route or working a crux where the material was abrading against a sharp edge a single sling sliding-x could cut.

I tend to be more concerned about redundancy when the anchor isn't constantly monitored.

That is quite an interesting observation, tho it can be explained due to geometry. A typical angle of 60degrees between the pieces gives a summed force of 15% more than the tension on the anchor master point.

I've no doubt you and lots of others can tie a knot in a sling lickety split. I also have no doubt that many MORE cannot do it quickly. And there is a select group, probably the largest of all, that ties and reties these things, at every single belay.

Worse people spending time to find the proper arrangement to fit their preconceived notions and -ette configs.

DMT

So your suggesting equalisation in of itself can be a bad thing? Test numbers are not necessary when the physics is obvious.

GOOD. Because I'm not selling the notion that every belay has to be equalised and/or limitted. But I am objecting to your claim that limitter knots are not effective in their purpose.

Napkin calcs have solid basis in maths and physics. You yourself have no 'facts' to speak of.

Why do you need a study for everything? I don't need a study to tell me that dental floss is not an appropriate material for a cordalette. The physics is fairly clear here and has been explained. All things being equal LESS extension is better. That is my position and I find it hard to believe that you continue to argue against it.


That is quite an interesting observation, tho it can be explained due to geometry. A typical angle of 60degrees between the pieces gives a summed force of 15% more than the tension on the anchor master point.

amateur troll n00bs always make a mistake by constructing a dumb anchor and ask a dumb question while trying to act like a n00b .

Can you clarify this statement? Does this statement mean that sometimes you think equalization is useful and/or necessary and sometimes you think limiting is useful and/or necessary?

It's ok, you're an American, and Americans believe that the proper application of technology will substitute for any lack of competence, talent, intelligence, skill, experience, training, or basic animal common sense. Come on in, and let's spend 7 pages in pointless, irrelevant, and above all, empirically unfounded armchair speculation about the physics of climbing anchors.

Yeah, maybe. Though I'm almost tempted to ask if *you* have empirical proof of all these gumbies running around tying themselves in knots (your own experience running into these gumbies is proof if you say you've actually seen such a thing). But I have a sneaking suspicion that you're tilting at windmills.

Why do you need a study for everything?

I don't need a study to tell me that dental floss is not an appropriate material for a cordalette.

The physics is fairly clear here and has been explained.

So it should be patently easy to demonstrate it.

And yet it hasn't.

DMT