NEClimbs.com forum

Please login or register.

Login with username, password and session length
Advanced search  

News:

Reading the forum on your cell phone? There's an easier way. We've enabled a Tapatalk app that makes browsing the forum a whole lot easier. Check it out in the iPhone or Android store if you don't own it already.

Pages: [1] 2   Go Down

Author Topic: Sliding X  (Read 315 times)

Admin Al

  • NEClimbs Administrator
  • NEClimbs God
  • *****
  • Offline Offline
  • Posts: 7089
  • Climb 'till your forearms turn to jelly!
    • NEClimbs
Sliding X
« on: October 26, 2002, 02:05:42 PM »

I came across the following by Chris McNamara on the http://www.safeclimbing.com web site. I see a lot of folks doing this, tho I gave it up some time ago. makes perfect sense to me.

any comments?

Al

--------

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.

« Last Edit: October 26, 2002, 02:07:36 PM by admin »
Logged
Al Hospers
____________________________________
my music
 https://www.facebook.com/BlackMountainRamblers

web hosting, design and software programming:
 http://www.cambersoft.com

dogboy

  • NEClimbs God
  • *****
  • Offline Offline
  • Posts: 555
  • What?
Re: Sliding X
« Reply #1 on: October 28, 2002, 06:23:52 AM »

I would be interested in seeing the numbers on extension forces...if you assume that a carabiner, loaded in the correct dimension, will take somewhere from 18 to 20 KN to break, it seems like it would be difficult to generate that kind of force in a regular fall...remember, dynamic ropes will not take nearly that much force...but I'm just guessing, since I haven't seen any numbers/studies.

Plus, I'm not sure why equalization presupposes that one piece would fail...I always assumed that equalization was used to spread the forces evenly over all pieces, to make it less likely that any of them would break...
« Last Edit: October 28, 2002, 06:26:22 AM by jeffc »
Logged
Everybody wants to go to heaven, but no one wants to die.

ccclimber

  • NEClimbs Junior Member
  • **
  • Offline Offline
  • Posts: 80
Re: Sliding X
« Reply #2 on: October 28, 2002, 06:40:39 AM »

Well, I'm gonna admit that I use this regularly. I have fallen on it and had a cam fail. The other held the way I thought it would. I do try to use a locking biner for the rope to run thru. The way I look at it, using two seperate slings, only equalizrs the two points when directly pulled from below. Any side to side motion nullifies the equalization making one anchor point and the other becomes a backup anchor point. I think it depends on many circumstances, I guess that's why I carry a cordallet/web-o-let/and many slings. One instance I can think of the x in my usage is about 20 feet out on the 3rd pitch of Sea of Holes you get a stance where there is a crack/flake. Before the runout to the overlap. I  get two pieces in it and equalize them with the X and use a screamer with locking biner for the rope to run thru.
Logged
Ed

Bueno Puno

  • Guest
Re: Sliding X
« Reply #3 on: October 28, 2002, 07:42:02 AM »

Screamers on Sea of Holes??????/

Are you rich or something?  I have done hard aid routes without screamers!  Do you carry hooks, beaks, and heads for whitehorse too?  

If your rich - can I be your partner?  We can place screamers in really scarry spots like Thin Air, They Died, and Kiddie Crack.

Sometiems on standard route on whitehorse - the bulge after the quartz pocket is a bit spicey and I have to break out the hooks (attached to screamers of course)  and hook up that hard part.  but its cool,  I leave the hooks in holes attached with screamers and maybe a few #5 camalots to keep them waited.  I am totally gay!
Logged

Bueno Puno

  • Guest
Re: Sliding X
« Reply #4 on: October 28, 2002, 07:45:56 AM »

  :)   ;)  :D  ;D  >:(  :(  :o  8)  ???  ::)  :P  :-[  :-X  :-/
Logged

dogboy

  • NEClimbs God
  • *****
  • Offline Offline
  • Posts: 555
  • What?
Re: Sliding X
« Reply #5 on: October 28, 2002, 09:18:39 AM »

Two further points...are we talking here about equalizing lead gear placements, or equalizing belay anchors?  Most often the x is used to equalize belay anchors where, given the number of factors invloved in the system (belayer, rope, runners, etc.), it seems like it would be hard to generate 20kn or so of force directly on the biners.  Second, the Whitehorse reference brings up a good point...the original post does not specify type of fall.  Are we talking about a factor 2 fall on a vertical face, or a slide on a slab?  Too little info....
Logged
Everybody wants to go to heaven, but no one wants to die.

om

  • NEClimbs Full Member
  • ***
  • Offline Offline
  • Posts: 209
Re: Sliding X
« Reply #6 on: October 28, 2002, 03:11:02 PM »

I'm with Dogboy on this. I can imagine little number of scenarios where the X setup will fail because of the forces involved. Even if one piece fails (which is less probable because of good equalization) it doesn,t mean the entire factor 2 fall force will be applied to the second piece. At least some of it will go on pulling the first piece out. In case of the top-rope setup on a bolt anchor - which I thought was mentioned in the article - the forces are minimal anyway. If the bolt is pulled out by the equalized top-rope fall - it should've fallen out when you were inspecting it before clipping.
However, I do have a problem with the X setup. The problem is luck of redundancy. If the sling is cut or weakened in one place the entire anchor fails. True, sometimes I clip in with a single sling, but I consider that different because when I do that I watch where that sling is touching the rock, what's running over it and after all it,s just me, not the entire party that relies on it.
So I would use the X as a part of an anchor, but not the entire thing.
Logged
-om

Admin Al

  • NEClimbs Administrator
  • NEClimbs God
  • *****
  • Offline Offline
  • Posts: 7089
  • Climb 'till your forearms turn to jelly!
    • NEClimbs
Re: Sliding X
« Reply #7 on: October 28, 2002, 04:27:10 PM »

Bueno, you are S U C H a punter!
Logged
Al Hospers
____________________________________
my music
 https://www.facebook.com/BlackMountainRamblers

web hosting, design and software programming:
 http://www.cambersoft.com

Bueno Puno

  • Guest
Re: Sliding X
« Reply #8 on: October 29, 2002, 05:03:54 AM »

What is punter?
Logged

dogboy

  • NEClimbs God
  • *****
  • Offline Offline
  • Posts: 555
  • What?
Re: Sliding X
« Reply #9 on: October 29, 2002, 06:04:29 AM »

In reference to om's post--I totally agree with you that using one sling introduces a point of non-redundancy into the system, but I try not to think about those sorts of things...unless you always climb on doubles, there is no redundancy in your rope system, but most climbers take it on faith that their rope isn't going to fail...this is not to negate your point at all, just to say that I guess I'm willing to take some things on faith (plus, if you look at tests done even on ratty, sun-bleached nylon slings, they're still strong enough to break biners in a cyclic stress tester....)

I'd be interested to know if there are any documented cases of climbers being injured when a properly tied or sewn sling broke....
Logged
Everybody wants to go to heaven, but no one wants to die.

Admin Al

  • NEClimbs Administrator
  • NEClimbs God
  • *****
  • Offline Offline
  • Posts: 7089
  • Climb 'till your forearms turn to jelly!
    • NEClimbs
Re: Sliding X
« Reply #10 on: October 29, 2002, 12:23:22 PM »

In this case a Punter is someone who makes bad jokes at other folks expense!
Logged
Al Hospers
____________________________________
my music
 https://www.facebook.com/BlackMountainRamblers

web hosting, design and software programming:
 http://www.cambersoft.com

Admin Al

  • NEClimbs Administrator
  • NEClimbs God
  • *****
  • Offline Offline
  • Posts: 7089
  • Climb 'till your forearms turn to jelly!
    • NEClimbs
Re: Sliding X
« Reply #11 on: October 29, 2002, 12:23:22 PM »

In this case a Punter is someone who makes bad jokes at other folks expense!

:-X
« Last Edit: October 29, 2002, 12:23:44 PM by admin »
Logged
Al Hospers
____________________________________
my music
 https://www.facebook.com/BlackMountainRamblers

web hosting, design and software programming:
 http://www.cambersoft.com

David Warriner

  • Guest
Re: Sliding X
« Reply #12 on: October 29, 2002, 02:24:18 PM »

I have used this technique on occasion for pieces on lead.  Basically, it is an act of desperation, and even as I set this sort of thing up I know in the back of my mind my time is better spent climbing and I am just being a weeny.  Usually, there are ice screws involved and some running water.  Nevertheless we all have our stupid little ways to procrastinate while doing a lead and this is a beaut.  You can put off climbing for at least 10 minutes on ice - and if rock is your medium, then you're in heaven.  A determined procrastinator on rock could easily eat up 20 minutes once the brass nuts and other fussy pieces make an appearance.

As an anchor, I think it is a total waste of time.  Presumably, you would only need to do this on 2 sketchy pieces.  Whatever you gain by loading each piece perfectly, you lose that much more by shock loading the remaining piece.  The ironic thing is that even if the forces are minor in regard to the extension, if your gear is so sketchy as you have to actually go through the machinations of having to equalize 2 pieces to get them to hold, that means the shock loading of the 2nd piece would probably cause it to fail.  For this, you give up redundancy.  I am a huge fan of redundancy.  I am a huge fan of redundancy.  (sorry I couldn't resist).  Lastly, you can get pretty good pseudo equalization if you stick a knot in the system.  The good thing about an anchor is you have a pretty good idea where the direction of fall and forces will come from and anticipate accordingly.  A well placed knot will get you 95% of what perfect equalization will, without the drawbacks.

If both pieces are bomber then it is a total, total a waste of time.  By doing this you are now making the sling a single point of failure (although I will admit that this is *extremely* unlikely) but why bother?

Lastly, if you mess up when you put the half-twist in the sling, you're not actually inside the sling.  This means if one piece fails, your actually not in the loop and you die.  It is hard to determine whether you are in or out of the sling by visual inspection.  Yes, this should never happen to a competent climber, but sometimes it does.  So again, why bother?

-David
« Last Edit: October 31, 2002, 08:33:33 PM by admin »
Logged

RDoucette

  • Guest
Re: Sliding X
« Reply #13 on: October 30, 2002, 08:38:22 AM »

I have used it and will continue to do so.  People seem to have missed a couple of important points...maybe it was in there somewhere and I missed it.
The sliding X is most useful if the direction of pull on the anchor could change. In a belay anchor you might move around on a ledge, so it could have value. As a climbing anchor the direction of force could change a little as you fall past this shitty equalized piece, so it could be useful there.
As far as extension goes, that is a valid concern, but its not gonna break the friggin beaner.  The sling will go way before that.  Extension is easy to eliminate, just tie a knot in the sling that is too long...near the sliding biner.
Logged

jay conway

  • Guest
Re: Sliding X
« Reply #14 on: October 30, 2002, 11:07:51 AM »

David says:

"For this, you give up redundancy.  I am a huge fan of redundancy.  I am a huge fan of redundancy.  (sorry I couldn't resist)."

that was pretty good!
Logged
Pages: [1] 2   Go Up
 

Page created in 0.169 seconds with 22 queries.