The Sliding X

Ian Cavanaugh wrote: youtube.com/watch?v=Vrgadjo… This may be on a 120cm sling and not a 60, the loads are very similar. Im pretty sure that during a shock load set up, 14.9kn and higher are not a "small increase in load". the dynamic rock is not going to lessen the impact you are experiencing is you are clipped directly to the anchor. That being said, in certain circumstances i do use a sliding x. But I always use a 120 for my anchor. or the rope itself. for TR setups, two draws.

Geez kid. Is your degree a BS in "I watched a video, now I'm an expert" from Google University.

First off, the tests in the video are like testing car air bags at 400mph. You should never get in this situation in the first place. But, they used worst case scenario for test purposes... fine.

Second, I specifically mentioned a 24 in sling which would lead to approx 12in extension. I would not recommend a sliding x without limiter knots on a 48 in (60cm) sling.

Third, when are you loading an anchor without the rope somewhere in the system. The exception when attached directly with probably the PAS in your situation. But, now you only have body weight on the anchor. If your gear fails in this situation, stop climbing forever. The load has to come from somewhere. Top rope fall, lead fall. Unless you decide to climb above your anchor while still attached, then fall. Again, stop climbing forever.

Just for fun, lets use the video with 60cm sling and sliding x anyway.

What you failed to consider from the video is the additional load generated by the extension compared to the load if the gear did not fail. The mysterious "shock load". The first test with sliding x and Fall Factor 1 generated over 16kN. Yet, the second test with 2mm attachment to represent a failed piece only generated 14kN on the remaining piece. Hmmmm. Your use of the number was quite misleading.

What would be interesting to see would be a slinding x with limits of extension of 12", 24" and 36". This would be more pertinent to this discussion.

But, if we are to gain anything valuable from that video is an anchor with nylon and knots absorb energy much better than anchors with dyneema and no knots which is why my anchors always have some nylon, knots and or the climbing rope incorporated, top rope anchors excepted.

gf9318 wrote:http://www.safeclimbing.org/education/slidingx.htm When there is an option to avoid shock and increase redundancy, take it.

Whoever wrote this is an idiot.

"While the sliding X does equalize the pieces, it assumes that neither could break, since if one does break, there is severe extension in the system - enough that it would likely cause the carabiners to break."

I'm quite certain neither biner nor the sling will break unless you take a factor two directly clipped into the anchor or some dumb situation like that.

I don't like a sliding X without using limiter knots. I keep one tied with limiter knots to use on single pitch bolted anchors. It keeps the wear concentrated to two cheaper biners.

The whole point of "equalization" is to share the load when one or more pieces is marginal. Why the FUCK anyone would do this instead of finding a bomber anchor, I have no idea. There are VERY few instances where this is the only option, and the vast majority of them are likely alpine.

the sliding x is for load distribution, not redundancy -- certainly alpine has been by far the place I've used it. and, not that it's perfect, but it works.

Load equalization is very important, especially on slabs. When retrobolting an existing climb, one should add not just add one bolt, but two bolts at critical locations. This allows safety conscious climbers to capitalize on the added safety of the sliding-x and minimize their risk of injury during a fall. A quad also works well in these situations.

I always fall back to the NERDSS analysis: (Ne=No Extension, R=Redundant, D=Distributed, S=Strength, and S=Simplicity)

The sliding X fails both the No Extension and Redundancy aspects of a NERDSS analysis. However it is probably the best for Distribution and Simplicity. No anchor system is 'perfect' when a NERDSS analysis is performed. You typically trade a reduction in one aspect for an increase in another, but you can improve the sliding X by adding limiter knots to increase redundancy and limit the extension.

Edit: I swear I wrote this before watching Mike's Mail video (which takes 20 minutes to say what I said)

John Marsella wrote: This is, of course, the corollary to the rule that I follow when doing trad routes: always place 2 pieces of gear at every point of protection and equalize them. This works especially well for #5s in nasty OWs.

Only two pieces!!??

John, you're like the Alex Honnold of trad, running it out like that. :-)

I've always used the rope wherever possible when climbing multi-pitch routes or single pitch where I don't have to lower off (i.e. sport routes). Either clip the bolts and clove hitch the rope with enough of a bight to tie an 8 or clove hitch to clip into my harness. Or if I'm placing gear do the same thing.

Because it uses rope it requires that I don't run the pitches to full length but I generally don't do that anyway (especially now we have 70 meter ropes), as I like to stop on decent/comfortable stances/ledges if they're available.

I found a sliding x useful in this marginal situation. This was my theorized pseudo dynamic rope solo belay anchor. I fall tested the first piece and was happy to get the first good piece to clove to. The 60 lb block is loaded and raises before the pin and nut anchor is loaded. The sliding x was an attempt to distribute loads and adjusts in the moments the block raises. Seem to work well though next time i am in a similar situation i just assume i would drill a couple holes for RBs or bolts.

don'tchuffonme wrote:The whole point of "equalization" is to share the load when one or more pieces is marginal. Why the FUCK anyone would do this instead of finding a bomber anchor, I have no idea. There are VERY few instances where this is the only option, and the vast majority of them are likely alpine.

Well ANYTIME sandstone is involved, bolted or gear, it's kinda nice to equalize, especially in the Utah desert.

Then any trad or multipitch trad with or without bolted anchors.

Certainly any ice climbing anchor that is not a tree.

And I've equalized every single anchor when doing multipitch sport.

whats better- a sliding X anchor with one sling and one biner OR an un-equalized anchor with 2 slings and 2 biners?

I think I'd rather whip and/or or rap on the equalized one

Just carry 30ft of 7mm cord (or 6mm if you want to go light) and make a quad when needed. Equalized, redundant, no extension etc. Nylon gives slightly. All good qualities.

The bonus is that you can make a BFK masterpoint if you have 3+ anchors or use the cordalette to make a long arsed sliding-x if needed.

I choose 7mm as it has a ~10kN MBS which means as a loop each leg will have 20kN with maybe a 30% reduction due to knots (nylon is more forgiving with knots). Dynema/spectra loses 50% due to knots.

Oh yeah. 7mm 30ft cord is about $12 or cheaper if you look. Dyneema/Spectra is more expensive. Yep lighter but not as versatile.

As long as I have some left I use the rope I'm climbing on....quick, less gear, bomber

Darren Mabe wrote:I found a sliding x useful in this marginal situation. This was my theorized pseudo dynamic rope solo belay anchor. I fall tested the first piece and was happy to get the first good piece to clove to. The 60 lb block is loaded and raises before the pin and nut anchor is loaded. The sliding x was an attempt to distribute loads and adjusts in the moments the block raises. Seem to work well though next time i am in a similar situation i just assume i would drill a couple holes for RBs or bolts.

My view:

Slding-x has no redundancy. If you cut one leg of the sling bang goes your anchor. Use 2 slings if you do it this way.

Gaz wrote:Just carry 30ft of 7mm cord (or 6mm if you want to go light) and make a quad when needed. Equalized, redundant, no extension etc. Nylon gives slightly. All good qualities. The bonus is that you can make a BFK masterpoint if you have 3+ anchors or use the cordalette to make a long arsed sliding-x if needed.

Except a quad takes forever to tie. For multipitch I carry 21 feet of 7mm cord for anchors, and if I'm using that material on two bolts I just tie a masterpoint. A quad is ridiculously bomber, to the point that it is un-needed. Now when I find myself on bolts, I just use a double length sling to a masterpoint.

The only time I use a sliding X is for top rope anchors, but I'm quickly getting to the point where I don't use it there, either.

A quad takes forever to tie ??? Make a loop (as you would with any cordalette). Double it up and do one overhand at each end. Clip 2 lockers into the 3 of the 4 strands in the middle, clip the ears to the anchors. Seconds. Done. Bomber.

If you're worried about the seconds it takes, pre tie it and you can undo it when need be.

vimeo.com/65101674

Btw, in this video I don't like the way he's on a single cord when cleaning the anchor/setting up the rappel cord. He could quite easily use one or 2 of his draws and back himself up. Alternatively use the rope as a tie off to the anchor (more convoluted process and timely but doable - you can always be tied to the rope until you're ready to belay).

Nick Votto wrote:As long as I have some left I use the rope I'm climbing on....quick, less gear, bomber

Spot-on... :-) Bunny ears to anchor, use the shelf for belaying.

The quad I'm referring to is useful for lots of things. Prusik, extended anchor, sliding-x, shoe laces, hair ties, etc. ;-)

Oh yeah and if you need to jug your rope for some reason, 30ft of 7mm is perfect. Purcell prusik for foot loop and then an overhand, make 2 prusiks and you have a foot loop and a harness loop with 2 prusiks to jug on. Easier to show than explain in text. Does take some time to make but if needed then you take that time.

Harness broken ? 30ft of 7mm can make a swiss seat rappel harness (not a climbing harness). Double up on leg loops and if you can pad your thighs do it !!

mountainproject.com/v/rock-…

A pretty good reason to not use the sliding x for a bolted anchor.

To finish his sentence: you'd be dead.  Read the above accident report.  Maybe consider the advice you were given from someone professionally trained who does this for a living.

Danny wrote:

in this limited experiment, kolin powick shows that a sliding x with no knots is quite burly strong and that knots only weaken the sling, and the whole anchor. the machine couldn't even break the sling. last weekend a guide criticized my sliding x top rope anchor saying "if a piece blew" (bomber new bolts) or "if your sling snapped" (nylon) ... i wish i could show him this:

http://blackdiamondequipment.com/en_US/experience-story?cid=qc-lab-sling-strength-in-3-different-anchor-configurations

If you have 2 bomber bolts, what is the point of using a sliding x?