Forums: Climbing Information: Beginners:
Sliding X Question
RSS FeedRSS Feeds for Beginners

Premier Sponsor:

 
First page Previous page 1 2 3 4 5 Next page Last page  View All


CurlyFries


Sep 1, 2011, 5:11 PM
Post #1 of 110 (7571 views)
Shortcut

Registered: Aug 22, 2011
Posts: 23

Sliding X Question
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

I am putting together my first TR kit. In the past I have always done my anchors by slinging two bomber trees with webbing long enough to almost meet. Then I connect the two pieces of webbing with biners to a sling acting as a sliding x.

Would it be fine to use two slings instead of one? I was just thinking that everything in the system is backed up except for the sling. Having two slings put together would make the system more redundant, but would it create any unnecessary friction possibly messing with the sliding x?

Thanks!
Dave


(This post was edited by CurlyFries on Sep 1, 2011, 6:40 PM)


rescueman


Sep 1, 2011, 7:36 PM
Post #2 of 110 (7523 views)
Shortcut

Registered: Mar 1, 2004
Posts: 439

Re: [CurlyFries] Sliding X Question [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (3 ratings)  
Can't Post

Unless you're planning to use one anchor for multiple routes or climb far off-route, a fixed focused multi-point anchor is safer than a sliding X.

The sliding X does not equalize well under shock loads. Just use a single piece of webbing or static line, or take the two pieces and tie an overhand on a bight as a master point.

Use the KISS principle and don't over complicate a simple top rope anchor.


Kartessa


Sep 1, 2011, 8:16 PM
Post #3 of 110 (7498 views)
Shortcut

Registered: Nov 17, 2008
Posts: 7358

Re: [CurlyFries] Sliding X Question [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post



your "belay points" can be the webbing attached to the trees.


styndall


Sep 1, 2011, 8:57 PM
Post #4 of 110 (7481 views)
Shortcut

Registered: May 29, 2002
Posts: 2741

Re: [rescueman] Sliding X Question [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (3 ratings)  
Can't Post

rescueman wrote:
Unless you're planning to use one anchor for multiple routes or climb far off-route, a fixed focused multi-point anchor is safer than a sliding X.

The sliding X does not equalize well under shock loads. Just use a single piece of webbing or static line, or take the two pieces and tie an overhand on a bight as a master point.

Use the KISS principle and don't over complicate a simple top rope anchor.

It's a top-rope. There aren't shock loads.


rescueman


Sep 1, 2011, 9:14 PM
Post #5 of 110 (7470 views)
Shortcut

Registered: Mar 1, 2004
Posts: 439

Re: [styndall] Sliding X Question [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (7 ratings)  
Can't Post

styndall wrote:
It's a top-rope. There aren't shock loads.


Don't kid yourself. Unless you keep the belay tight to the climber at every moment, then any fall is a shock load.

Even a fall on a perfectly tight belay imparts double the climber's weight on the rope and about 1.67x that on the anchor.


(This post was edited by rescueman on Sep 1, 2011, 9:15 PM)


redlude97


Sep 1, 2011, 9:18 PM
Post #6 of 110 (7464 views)
Shortcut

Registered: Aug 27, 2008
Posts: 990

Re: [rescueman] Sliding X Question [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (4 ratings)  
Can't Post

rescueman wrote:
styndall wrote:
It's a top-rope. There aren't shock loads.


Don't kid yourself. Unless you keep the belay tight to the climber at every moment, then any fall is a shock load.

Even a fall on a perfectly tight belay imparts double the climber's weight on the rope and about 1.67x that on the anchor.
Are you such an authority that you can just make up new meanings for well established terms now?


rescueman


Sep 1, 2011, 10:02 PM
Post #7 of 110 (7440 views)
Shortcut

Registered: Mar 1, 2004
Posts: 439

Re: [redlude97] Sliding X Question [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (4 ratings)  
Can't Post

redlude97 wrote:
Are you such an authority that you can just make up new meanings for well established terms now?

No. But I'm such an authority that I know that the term "shock load" is one of the least well-defined and most misunderstood terms in climbing.

In physics, a "shock load" is typically a ballistic impact. But in rope work, a shock load is any sudden deceleration and there is no standard for how sudden.

So, in essence, there are only two kinds of rope system loads: static and dynamic (or shock). If a climber falls on anything but a perfectly tight rope, there is a shock load as the downward acceleration is arrested.

In the same way, the load on your feet from standing is a static load. The load on your feet (and knees) from jogging, jumping or even walking downhill is a shock load (and your knees will tell you that).


(This post was edited by rescueman on Sep 1, 2011, 10:03 PM)


patto


Sep 1, 2011, 11:38 PM
Post #8 of 110 (7417 views)
Shortcut

Registered: Nov 14, 2005
Posts: 1452

Re: [rescueman] Sliding X Question [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

rescueman wrote:
redlude97 wrote:
Are you such an authority that you can just make up new meanings for well established terms now?

No. But I'm such an authority that I know that the term "shock load" is one of the least well-defined and most misunderstood terms in climbing.

In physics, a "shock load" is typically a ballistic impact. But in rope work, a shock load is any sudden deceleration and there is no standard for how sudden.

So, in essence, there are only two kinds of rope system loads: static and dynamic (or shock). If a climber falls on anything but a perfectly tight rope, there is a shock load as the downward acceleration is arrested.

In the same way, the load on your feet from standing is a static load. The load on your feet (and knees) from jogging, jumping or even walking downhill is a shock load (and your knees will tell you that).

So you thought that it would be sensible to add to the confusion?


In the physics and engineering world that I've encountered a 'shock' is an event where the energy imparted happens over such a short time frame that it is easier to treat it as happening at a discrete time point. How short time frame is short depends on the circumstances.


Back in the world of climbing if there is a dynamic rope involved then we normally don't refer to it as shock loading.


(This post was edited by patto on Sep 1, 2011, 11:42 PM)


poedoe


Sep 2, 2011, 3:25 AM
Post #9 of 110 (7391 views)
Shortcut

Registered: Mar 25, 2005
Posts: 106

Re: [patto] Sliding X Question [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (5 ratings)  
Can't Post

I'm so sorry. Here, if you have a milkshake, and I have a milkshake, and I have a straw. There it is, that's a straw, you see? You watching?. And my straw reaches acroooooooss the room, and starts to drink your milkshake... I... drink... your... milkshake!


Partner j_ung


Sep 2, 2011, 3:39 AM
Post #10 of 110 (7388 views)
Shortcut

Registered: Nov 21, 2003
Posts: 18689

Re: [poedoe] Sliding X Question [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

poedoe wrote:
I'm so sorry. Here, if you have a milkshake, and I have a milkshake, and I have a straw. There it is, that's a straw, you see? You watching?. And my straw reaches acroooooooss the room, and starts to drink your milkshake... I... drink... your... milkshake!

I have no idea what you're talking about. But damn, is it ever funny. Laugh


Kartessa


Sep 2, 2011, 4:25 AM
Post #11 of 110 (7373 views)
Shortcut

Registered: Nov 17, 2008
Posts: 7358

Re: [j_ung] Sliding X Question [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

j_ung wrote:
poedoe wrote:
I'm so sorry. Here, if you have a milkshake, and I have a milkshake, and I have a straw. There it is, that's a straw, you see? You watching?. And my straw reaches acroooooooss the room, and starts to drink your milkshake... I... drink... your... milkshake!

I have no idea what you're talking about. But damn, is it ever funny. Laugh

Thanks Jay, I think you've just given me the best sig I've ever had.

Don't flatter yourself though, the standards have been pretty low.


CurlyFries


Sep 2, 2011, 4:31 AM
Post #12 of 110 (7370 views)
Shortcut

Registered: Aug 22, 2011
Posts: 23

Re: [patto] Sliding X Question [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

Agreed... From my limited understanding a shockload occurs when the system is impacted by a sudden static force.

The fact that a dynamic rope is being used and webbing has some natural stretch to it (although not really worth mentioning) the entire system will help to decelerate the falling climber. Because of this, I would not say falling on this system would be truly shockloading the system.

If the rope being used was static cord, then yes, a fall would cause a true shockload.

But please let deciding an appropriate way of connecting multiple anchors to a master point up to me... My question was asking if using two slings in an X instead of one would inhibit the function of the X, or cause any un wanted friction, wearing out the slings faster than normal.


(This post was edited by CurlyFries on Sep 2, 2011, 4:32 AM)


sungam


Sep 2, 2011, 4:38 AM
Post #13 of 110 (7366 views)
Shortcut

Registered: Jun 24, 2004
Posts: 26618

Re: [j_ung] Sliding X Question [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

j_ung wrote:
poedoe wrote:
I'm so sorry. Here, if you have a milkshake, and I have a milkshake, and I have a straw. There it is, that's a straw, you see? You watching?. And my straw reaches acroooooooss the room, and starts to drink your milkshake... I... drink... your... milkshake!

I have no idea what you're talking about. But damn, is it ever funny. Laugh
YOU HAVEN'T SEEN THERE WILL BE BLOOD??? WTF DUDEBRAH????

Unacceptable!


Kartessa


Sep 2, 2011, 5:21 AM
Post #14 of 110 (7349 views)
Shortcut

Registered: Nov 17, 2008
Posts: 7358

Re: [CurlyFries] Sliding X Question [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

CurlyFries wrote:
But please let deciding an appropriate way of connecting multiple anchors to a master point up to me... My question was asking if using two slings in an X instead of one would inhibit the function of the X, or cause any un wanted friction, wearing out the slings faster than normal.

And your question was answered with the suggestion to connect via cordelette rather than sliding x.


shockabuku


Sep 2, 2011, 5:43 AM
Post #15 of 110 (7342 views)
Shortcut

Registered: May 20, 2006
Posts: 4864

Re: [rescueman] Sliding X Question [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

rescueman wrote:
Unless you're planning to use one anchor for multiple routes or climb far off-route, a fixed focused multi-point anchor is safer than a sliding X.

Can you point to some empirical evidence, such as accident rates due to failure of the sliding-X vs. a cordellette, that lends credence to your statement that a fixed multi-point anchor is safer than a sliding-X?


lena_chita
Moderator

Sep 2, 2011, 6:35 AM
Post #16 of 110 (7320 views)
Shortcut

Registered: Jun 27, 2006
Posts: 5812

Re: [CurlyFries] Sliding X Question [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (1 rating)  
Can't Post

CurlyFries wrote:
I am putting together my first TR kit. In the past I have always done my anchors by slinging two bomber trees with webbing long enough to almost meet. Then I connect the two pieces of webbing with biners to a sling acting as a sliding x.

Would it be fine to use two slings instead of one? I was just thinking that everything in the system is backed up except for the sling. Having two slings put together would make the system more redundant, but would it create any unnecessary friction possibly messing with the sliding x?

Thanks!
Dave


Why use the sling at all? Can't you have the webbing pieces tied just a little bit longer, so all you have is two pieces of webbing (one to each anchor tree) and then two locking 'biners that go through both pieces of webbing? It may take a few minutes longer to get the length of both webbing pieces adjusted, but you are setting up single-pitch TR, do couple minutes really matter?


billl7


Sep 2, 2011, 6:45 AM
Post #17 of 110 (7313 views)
Shortcut

Registered: Oct 13, 2005
Posts: 1888

Re: [rescueman] Sliding X Question [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

rescueman wrote:
In physics, a "shock load" is typically a ballistic impact. But in rope work, a shock load is any sudden deceleration and there is no standard for how sudden. So, in essence, there are only two kinds of rope system loads: static and dynamic (or shock). If a climber falls on anything but a perfectly tight rope, there is a shock load as the downward acceleration is arrested.

I've taken a lot of falls on top rope and on lead and the majority of them did not feel like "shock loading". Many were down right spring-y perhaps akin to bungy jumping. In common sense (a.k.a., using terms in the way they are commonly understood), saying all those falls shock loaded the anchor would be confusing.

If we are just talking about falls onto a dynamic rope, a better climbing term is fall factor. It has a very clear defintion. And it puts the normal top-rope fall into a well-defined framework: pretty damn weak in terms of "shock loading" an anchor.

Bill L


sandstone


Sep 2, 2011, 7:15 AM
Post #18 of 110 (7295 views)
Shortcut

Registered: Apr 21, 2004
Posts: 324

Re: [CurlyFries] Sliding X Question [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

CurlyFries wrote:
... slinging two bomber trees with webbing long enough to almost meet. Then I connect the two pieces of webbing with biners to a sling acting as a sliding x.

In the case of using two bomber trees, I agree with others who have said the sliding x is not really needed. The addition of the sling and extra biners adds more gear (more potential points of failure) into what should be a very very simple anchor.

In reply to:
Would it be fine to use two slings instead of one? I was just thinking that everything in the system is backed up except for the sling. Having two slings put together would make the system more redundant, but would it create any unnecessary friction possibly messing with the sliding x?

Yes it is fine (and smart) to use two slings on a sliding X anchor, but don't put both slings through the same rope biner. Put a separate biner on each sling, then clip the rope through both biners.


scrapedape


Sep 2, 2011, 7:35 AM
Post #19 of 110 (7284 views)
Shortcut

Registered: Jun 23, 2004
Posts: 2392

Re: [lena_chita] Sliding X Question [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

lena_chita wrote:
CurlyFries wrote:
I am putting together my first TR kit. In the past I have always done my anchors by slinging two bomber trees with webbing long enough to almost meet. Then I connect the two pieces of webbing with biners to a sling acting as a sliding x.

Would it be fine to use two slings instead of one? I was just thinking that everything in the system is backed up except for the sling. Having two slings put together would make the system more redundant, but would it create any unnecessary friction possibly messing with the sliding x?

Thanks!
Dave


Why use the sling at all? Can't you have the webbing pieces tied just a little bit longer, so all you have is two pieces of webbing (one to each anchor tree) and then two locking 'biners that go through both pieces of webbing? It may take a few minutes longer to get the length of both webbing pieces adjusted, but you are setting up single-pitch TR, do couple minutes really matter?

Danger!!!!!! Triaxial loading!!!!!!!!1

------------

Here's my thinking on this topic:
In most TR anchors, redundancy (especially of the soft goods) is generally more important than load distribution. I think this because (1) in most cases you've probably got the luxury of bomber anchor points, (2) loads are not likely to be all that high, and (3) you're not able to continually monitor the anchor, as you are when you are right next to it.

The above conditions point me toward favoring a system that sacrifices some ultimate strength in favor of redundancy.

So, I would avoid things like a sliding X, which relies on a single sling which could be getting abraded without your knowing it.


carabiner96


Sep 2, 2011, 7:59 AM
Post #20 of 110 (7260 views)
Shortcut

Registered: Apr 10, 2006
Posts: 12557

Re: [poedoe] Sliding X Question [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

poedoe wrote:
I'm so sorry. Here, if you have a milkshake, and I have a milkshake, and I have a straw. There it is, that's a straw, you see? You watching?. And my straw reaches acroooooooss the room, and starts to drink your milkshake... I... drink... your... milkshake!
I will driiiink it up!


wwalt822


Sep 2, 2011, 8:03 AM
Post #21 of 110 (7255 views)
Shortcut

Registered: Nov 10, 2010
Posts: 116

Re: [rescueman] Sliding X Question [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (3 ratings)  
Can't Post

rescueman wrote:
Don't kid yourself. Unless you keep the belay tight to the climber at every moment, then any fall is a shock load.

I want to make a Reel Rock contest video where the characters only speak in quotes taken directly from this website. This would be one of them.


rescueman


Sep 2, 2011, 8:08 AM
Post #22 of 110 (7247 views)
Shortcut

Registered: Mar 1, 2004
Posts: 439

Re: [shockabuku] Sliding X Question [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (1 rating)  
Can't Post

shockabuku wrote:
Can you point to some empirical evidence, such as accident rates due to failure of the sliding-X vs. a cordellette, that lends credence to your statement that a fixed multi-point anchor is safer than a sliding-X?

It's dumbfounding that people today demand "scientific proof" for a practice that common sense would require. But common sense is, perhaps, the least common sense today.

Part of the SERENE principle (that is generally accepted) for any kind of climbing anchor is "no extension". A self-equalizing anchor allows extension upon failure of a single leg, which results in dynamic loading and shifting of the remainder of the system.

And, by the way, some climbers routinely top rope on static line, and webbing is a good deal more static than static line, which has up to 6% stretch at 10% of MBS.

The trees might, in fact, be "bomber" and 4,000 MBS webbing is more than strong enough, but webbing abrades and cuts very easily at an edge and there have been fatalities when climbers have used brand new webbing with taped joints from the manufacturer's spool. Improperly tied knots can slip apart. In other words, shit happens.

If one leg of the anchor should (for any reason) fail, then a sliding X would allow both sudden extension and a re-orientation of the remaining leg over the rock edge, potentially causing rapid abrasion and cutting.

Others here have advocated the same general principle: KISS. Don't complicate what should be a simple anchor system. The more pieces of gear, the more connections and - particularly - the more potential for sudden extension and abrasion, the more potential for failure.

KISS: Keep It Simple & Safe.


rescueman


Sep 2, 2011, 8:37 AM
Post #23 of 110 (7220 views)
Shortcut

Registered: Mar 1, 2004
Posts: 439

Re: [billl7] Sliding X Question [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

patto wrote:
So you thought that it would be sensible to add to the confusion?
As always, my purpose is to bring clarity, insight and common sense safety.

billl7 wrote:
I've taken a lot of falls on top rope and on lead and the majority of them did not feel like "shock loading". Many were down right spring-y perhaps akin to bungy jumping. In common sense (a.k.a., using terms in the way they are commonly understood), saying all those falls shock loaded the anchor would be confusing.

So you say the "majority" of your falls didn't feel "shocky", which says that some did.

If you're confused it's because we're not talking about the experience of the climber, but rather the "experience" of the anchor system.

Yes, dynamic ropes are required to limit the maximum impact on the climber to 12 kN - the assumed limit of survivability. And the strength of the rest of the system is calculated backwards from that value: anchors minimum 20 kN (1.67 x). And, yes, that's for FF2 falls, not top-roping.

The point is, when designing a "bomber" top-rope anchor that cannot fail under any conceivable circumstances, think like the anchor: can I slide and tear, can I extend suddenly and put a (pick one: dynamic, shock) load on my system, am I sufficiently redundant to compensate for possible failure points, am I loading all components (including knots and hardware) in the manner prescribed by their design, and I am simple as possible but no simpler?

A happy anchor is a SERENE anchor, and that should make the climbers serene as well.

Strong
Effective
Redundant
Equalized
No Extension

(from the 2008 AMGA Single Pitch Instructor manual)


(This post was edited by rescueman on Sep 2, 2011, 8:38 AM)


billl7


Sep 2, 2011, 8:43 AM
Post #24 of 110 (7213 views)
Shortcut

Registered: Oct 13, 2005
Posts: 1888

Re: [rescueman] Sliding X Question [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

rescueman wrote:
billl7 wrote:
I've taken a lot of falls on top rope and on lead and the majority of them did not feel like "shock loading". Many were down right spring-y perhaps akin to bungy jumping. In common sense (a.k.a., using terms in the way they are commonly understood), saying all those falls shock loaded the anchor would be confusing.

So you say the "majority" of your falls didn't feel "shocky", which says that some did.

... and a lot didn't. Why would I lump them all together under a term that doesn't fit most?

I can understand alerting people to the issue. At the same time, shoe-horning in the word "shock load" for every fall appears disingenuous.

Bill L


michael1245


Sep 2, 2011, 8:56 AM
Post #25 of 110 (7203 views)
Shortcut

Registered: Nov 23, 2010
Posts: 247

Re: [CurlyFries] Sliding X Question [In reply to]
Report this Post
Average: avg_1 avg_2 avg_3 avg_4 avg_5 (0 ratings)  
Can't Post

CurlyFries wrote:
I am putting together my first TR kit. In the past I have always done my anchors by slinging two bomber trees with webbing long enough to almost meet. Then I connect the two pieces of webbing with biners to a sling acting as a sliding x.

Would it be fine to use two slings instead of one? I was just thinking that everything in the system is backed up except for the sling. Having two slings put together would make the system more redundant, but would it create any unnecessary friction possibly messing with the sliding x?

Thanks!
Dave

A sliding-x isn't redundant.

For TR, if you need to use a sling or cord to create the master point tie an 8. Best bet for tree anchors is a big long static rope.

I wouldn't use a sliding-x as a master point. I would use a sliding-x to equalize two anchor points to one point (with a third point independant of the x).

First page Previous page 1 2 3 4 5 Next page Last page  View All

Forums : Climbing Information : Beginners

 


Search for (options)

Log In:

Username:
Password: Remember me:

Go Register
Go Lost Password?
$13.46 (10% off)
$53.96 (10% off)
$7.65 (10% off)
$15.52 (10% off)



Follow us on Twiter Become a Fan on Facebook