Yeah, I vote with Brad, too. And it doesn't sound like he was banking on double holding power. :)

No I understand the sliding X versus two separate slings thing.

I was pointing out that when you learn the sliding X - make sure you twist it. Otherwise that is the "death" part...an overclip of a sling. I wasn't saying anyone was advocating that. You do have to learn the twist though. It isn't intuitive.

It's just that I've never heard anyone refer to the sliding X as the "DEATH X" Sure I've heard the shock loading fears and hence I stopped using them for a while until I learned a bit more about backing them up etc...

Isn't the American triangle another thing completely. Seen often at rap anchors. So while Americans were using triangles Euros were busy with death knots?

Yeah, you're probably right about the American triangle. I've heard two versions. One was that the sling angles in triangle bolt belays increase stress and cause failure of the bolts. The other was a rumor that the party of three that fell off the Nose years ago resulted from clipping a pinch around the top two sides of the triangle, so that when the top bolt blew, the biners just slid right off of nothing and ...horror.

I recently read about the effects of different materials (spectra, dyneema, nylon, etc.) on absorbing shock. Basically, spectra/dyneema, in all its strength and glory, puts a lot of load on all components (including itself) as it doesn't stretch. Nylon, on the other hand, is quite dynamic and stretches and absorbs to a certain extent, putting a lot less stress on the system.

With that in mind, which material do you feel more comfortable using for slings/runners in our sliding x to connect two pieces of pro?

Also, can you keep tension on the two opposed pieces with a sliding x? When possible (mostly with anchors), I've tossed a clove onto the opposed pieces and tightened it up to make sure both pieces have tension so there is no extension when loaded.

Mal, I read about the Taqhitz accident but not the Sandias one. Anyone know of a link to the report?

Having read John Long's book, I now use the Equalette, and find it easy to use and feel a bit more comfortable in terms of how it addresses an unpredictably arcing fall, where the force increases as the pendulum is occurring. The book clearly describes how the cordelette does not actually equalize the force on each piece, and since it has no multi-directional capability is actually not as good as the sliding X or the Equalette, in the tests they performed.

With that said, the biggest question mark is really the quality of the rock and how well it will hold, and that is where SREN is a good practice. What I'd like to emphasize for novice and experienced climbers is that sometimes we judge a placement to the best of our ability, and sometimes when loaded, the rock just crumbles, whether we expect it or not. I once fell on a piece that I thought was totally bomber when I placed it, and the rock blew, and next thing you know I was sailing forty feet. When I climbed back up and inspected the former placement I could not believe what the force of the fall did to that chunk of granite!

Tim, I think there was a good write up of that accident in a back issue of R&I. I think Allison Osius wrote it. Or it may have been climbing. For a while there you couldn't tell the difference because of the revolving door between the 2 mags.

Mal

What we can do is play it safe, which comes down to Malcolm's rules.

I completely agree. There's nothing wrong with "The School Of Paranoid Climbing"...

I think everyone who is reading/posting to this thread has at least a passing interest in maximizing their safety in the mountains. That being said, I think there are two different approaches to trying to find new ways of being safe(r).

1) Take a careful, objective look at all the systems, gear, and methods we use to climb and descend. Although valuable, this is often complicated by the fact that the forces involved are very complicated.

2) Look at the causes of accidents/deaths in climbing and look for patterns.

I think option #2 is useful for looking at the Sliding X question. I don't have the equipment or skills to accurately and scientifically test the results of shock-loading a Sliding X where one side has failed. Instead I can look at my own experience and the experience of others and ask, what _does_ harm climbers? I'm sure a careful reading of the Accidents in American Mountaineering texts would come up with at least one example of a failing Sliding X but it's not a common cause of accidents. So, while I'm not trying to devalue any attempt to better understand the forces and risks involved with using the technique, I think it's also important to understand we're all more likely to die doing something universally seen as stupid, like rappelling off the ends of a rope because we failed to tie a stopper knot in the end.

maybe the better question with this topic is to ask how to go about trying to rig for marginal placements?

touche