Roger that, can confirm that taking the big ride when only half your anchor blew is a Bad Thing™

over and out

Edit: Wait, what are you asking? There's no way to clip both with a single biner without an X and not be vulnerable to option B. Do you mean just clip one strand?

RGold,

That's another good go at a firewalled rig. This is a -2x version of charlesjmm's rig a few pages back: I haven't set either up and will when I get home. Like I said, I certainly see the logic in putting a firewall between extension and equalization but I still have my doubts about the ultimate efficacy and utility of doing so given the hardware required. I'd probably just lose the rings as well and go straight through the biner. I bet in real application the difference would be of negligable impact on the net results. Also not sure that I wouldn't just use three [trad] draws and a slightly longer equalizing piece to make it.

charlesjmm photo:

http://i42.photobucket.com/...erdavid/DSCN0082.jpg

That's another good go at a firewalled rig. This is a -2x version of charlesjmm's rig a few pages back: I haven't set either up and will when I get home. Like I said, I certainly see the logic in putting a firewall between extension and equalization but I still have my doubts about the ultimate efficacy and utility of doing so given the hardware required. I'd probably just lose the rings as well and go straight through the biner.

The rig you posted (which isn't charlesjmm's) doubles the load to the middle anchors. I can't see any reason to do this when it is easily avoided.

This may be just a matter of linguistics, but I don't think there's anything to the concept of "firewalling" between extension and equalization, at least not in the picture I posted. Both equalization and extension happen in the part I called the "equalizer." The point of doing it in a way analogous to my picture is to use an equalizer with no limiter knots that has a short extension by virtue of relatively little total sling length.

As for the rings, I agree that one might profitably do without them. I put them in because of one of those untested hunches I just got done heaping scorn on: I have this image of a piece failing and the resulting turn of sling ending up over the gate of the biner. Whatever the impact the system takes would then produce an inward force on the gate, a rather unhappy prospect.

I think there is a rather obvious flaw in that ASCA argument.


Their premise is dead wrong. You don't use the sliding X assuming that neither could break. You use it because you do not know whether one will break, nor do you know, if one breaks, which one it will be that breaks. So you use it because you want each bolt to take the least amount of force possible, thereby increasing your chances that neither one will break.

You always use 2 slings for redundancy, and you tie knots to limit extension. You can tie the knots so that the amount of extension would be no more than what is possible even with a cordalette when the direction of force happens to be somewhat away from the line that was anticipated, which is not unusual.

Also, the issue regarding whether it will actually dynamically equalize under load is not really an issue. Most of the time it is already oriented in the direction of force, and it if is not it then it is no more out of line than what you would get with a cordalette.

I think it really comes down to personal preference, because if we're talking about a 2 bolt anchor, where the bolts and rock look solid, it doesn't matter what the heck you use.

Another point, as bostonclimbah mentioned, is speed and efficiency, and I'll add convenience to that. I keep a sliding X anchor rig on my harness, pre-rigged, knots tied and everything, ready to go. It takes me 5 seconds to build a 2-bolt anchor. The knots are tied to limit extenstion to 3 inches, and this still allows a 45 degree deflection to each side of vertical. Those are 27kn slings. This thing is truck. You'll also notice that I use 2 lockers at the bottom, and they are not opposed. This allows for very easy clipping and unclipping of the power point. Also, each locker is clipped to a seperate sling, allowing smoother movement (dynamic equalization) than if they were both clipped to both slings.

http://www.rockclimbing.com/...p.cgi?Detailed=41579

Many climbers use a "sliding X" to equalize two pieces - ususally beginner climbers with bolt anchors. You should NEVER use this except in two specialized cases (see below). 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. Since it assumes neither piece would break, it's a stupid system - if neither would break, there's no need for equalization. If one might break, then there is WAY too much extension. This is why many call it the "death X." Instead, use one sling off of each bolt or piece. You can tie one shorter to approximately equalize the pieces if needed.

The two cases where the sliding X is used:

equalizing tenuous pieces in a larger anchor - for instance, two poor nuts in a large natural pro anchor. The nuts are equalized, then the sliding X is equalized with other pieces through a cordelette, webolette, or other non-extending method.

equalizing two very tenuous pieces in extreme aid - for instance, a hook and a bashie on A4 terrain.

OMG. None of the previous three showed up when I tried posting. Now they're all here. Argh. Quadruple post, a new record.

Couldn't you just eliminate the rap rings on the bottom equalizer?

It seems the sliding W (three leg magix X with no limiter knots which would kill the equalization) or the gordolette (which I haven't tried yet) is the only way shown so far to truly equalize among 3 placements.

hugepedro,
Isn't the right leg in your anchor bearing 50% of the load, and the middle and left two anchor points 25% apiece?

= hugepedro You'll also notice that I use 2 lockers at the bottom, and they are not opposed. This allows for very easy clipping and unclipping of the power point.

I would not do that for a top rope anchor.

As far as the top rig with a sliding X on a 4' sling, and a sliding X on a cordelette, no ones saying that isn't a viable option, just looking for a better solution. In some situations that may be the best bet, but the equalette may be better in other situations with one less 4' sling and biner, and perhaps better equalization.

For the powerpoint on multi-pitch anchors I've been using a large biner like the BD rocklock or Petzl William. Much easier to clip and unclip your direct tie in, etc. without having to unweight the anchor.

As is, folks are worried about climbers not being able to tie a few simple knots without getting confounded. To me this is totally ridiculous. In any other endeavor that is potentially dangerous we expect folks to learn how to do thing to safeguard the adventure. Climbers simply have to learn some basic stuff, and that's a fact. To expect rigging to be totally brainless and foolproof is to expect too much from those struggling to cook up these systems, and expecting too little from those who will someday us these systems. Compared to what others learn--and must exercise-- to fly a plane or scuba dive, climbers are obliged to know very little indeed. But it will never get to the point to where they will have to understand nothing at all.

JL

Wowzer, some of these rigs remind me of the time I dosed my pet spider:

:lol:
johngo

I've always been a huge KISS fan... The more garish anchoring rigs come into their own for various reasons in various circumstances.

I like this one a lot. Sets up quickly, equalizes perfectly no matter the angle. I only see two problems with it: 1) exessive extension. With a 20ft DueGlidealette and 3 equal arms the failure of one peice dropped the powerpoint about a foot, which I belive is beyond the limit of safe extension outlined early in this thread by JL. 2) There is no easy way to adjust the height of the powerpoint. If the only protection at a belay stance is at head level you'll end up with a powerpoint down by your feet. I don't doubt there are knots to take up some slack, but they aren't one of the 4 or so knots I know how to tie well.

edit: nevermind. You can easily take up any amount of slack by just clove hitching a biner into one of the arms. I can post pics if anyone is interested.

Knots are easy, that isn't the problem. Understanding the physics of falling is beyond the grasp of most climbers...go to a crag and ask around, more than likely few can properly explain theoretical fall factor (let alone actual fall factor) or what the most important number is on a carabiner (hardly anyone will say open gate). It's taken a decade for climbers to finally understand that the cord-o-death has serious drawbacks for trad; should have been obvious but very few got it or said anything. Just look at some of the pics in this thread where people don't capiche the pulley effect.

Sounds like you're combining the two anchor books into one encyclopedia of rigging that will overwhelm the majority and only help a minority. Of course it all makes total sense to you and people like rgold because you're emersed in it. But a lot of things you take for granted go right over the heads of many climbers -- this thread is mostly populated by nerds and look at all the confusion ;-) Book authors (not just JL) often assume a greater understanding of science by the average person than our education system justifies. At least with flying and scuba, students are required to take courses from an instructor and pass tests but climbers aren't even required to read a book (yet).

Include the fancy rigs in the back if you must but spending more space up front explaining the very basics of physics (that none of your books cover, or any other instructional book for that matter) will be more valuable to more climbers IMHO. That will prevent more mistakes than just offering up 101 ways to rig 4 nuts with pros and cons on each. After all, geezers are just going to flip through it and look at a few sections to pick up an idea here and there. It's the people starting out and the ones beginning to get serious about trad who will read it all.