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crazy_fingers84


Apr 25, 2008, 9:26 AM
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SLACKLINE FAILURE! ! !
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A friend of mine set their slackline up earlier this week and the damn thing broke on her. She took these pictures of the faulty carabiner. I am amazed that the carabiner failed before the webbing broke.



I wish there was a picture of the half of the carabiner that is missing, but when the slackine broke it launched so far that she could not find it anywhere.
To explain the situation, the slackline was set up using 5 carabiners in a 5:1 pully system. The line was pulled very tight, and the person walking it at the time of failure was about 250+ lbs. She said when the line broke, "it was like a gun shot going right past their faces". It is incredible that nobody was injured badly. The person walking was hit in the foot on a ricochet and has a pretty swollen foot, nothing broken though.
The history of the carabiner is a little foggy. . . it was bootied at the NRG last year. I guess it wasn't good enough to climb on. . . this is a hard lesson learned. I find this very troubling because every time I set my line up, I picture the carabiner hurtling toward my face. . .


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Apr 25, 2008, 9:39 AM
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That webbing has a rating of about 5000 lbf/22.2kN. The caribiner around 5395lb/24kN.

Depending on how it was tensioned it may have been crossloaded. But since we can only assume as to how the system was rigged we can only assume the reasons it may have broke. Being a bootied biner also, as you stated, brings into question of the history of that particular biner. Maybe one of the engineering types can provide a better analysis of the possibility of failure based on where the biner broke.

I use an exclusive set of caribiners for slacklining and purchased them just for the set up that I have.


reg


Apr 25, 2008, 9:47 AM
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just a presumption of course but i agree with you. blue tape indicates former use leading or tr'ing - could have been dropped and then relagated to bail/racking status then used for the line leading to failure.
now that we have said what we think - let's hear from the op about the biner!


crazy_fingers84


Apr 25, 2008, 10:03 AM
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the blue tape was just to distinguish a slackline only carabiner from the rest of her climbing gear. she only ever used that biner for slacklining, but like i said . . . it was bootied. i believe that carabiner was found clipped into a petzl mini triaxion at the NRG a year ago. the carabiner (and triaxion) were found sitting on the ground . i have no idea what happened to the carabiner before she acquired it. i think that it is a black diamond carabiner, but i am unsure what model it is. the carabiner was probably loaded triaxely (sp?). it is also unclear as to whether the gate was open.


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Apr 25, 2008, 10:42 AM
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http://www.rescueresponse.com/store/carabiners.html

Steel


majid_sabet


Apr 25, 2008, 11:26 AM
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 I wonder how they guys really stay alive doing what they do.

I took this photo in my gym for reference to point out biner cross loading.








shockabuku


Apr 25, 2008, 11:39 AM
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majid_sabet wrote:
to point out biner cross loading.






??crossloading??


sterlingjim


Apr 25, 2008, 11:43 AM
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Looks like classic open gate failure to me.


troutboy


Apr 25, 2008, 12:28 PM
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shockabuku wrote:
majid_sabet wrote:
to point out biner cross loading.

[IMG]http://b.imagehost.org/0621/04-06-07_2000.jpg[/IMG]

[IMG]http://b.imagehost.org/0621/04-06-07_1957.jpg[/IMG]

[IMG]http://b.imagehost.org/0621/04-06-07_1959.jpg[/IMG]

??crossloading??
Me too on the ???? I don't see anything cross-loaded in those photos.

TS


marc801


Apr 25, 2008, 12:32 PM
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Like shockabuku implied, none of those biners in your photos are cross-loaded. There are some other funky things going on, but cross-loading isn't one of them.


Partner xtrmecat


Apr 25, 2008, 12:43 PM
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  I see some loads on that locker that are very bad. Maybe warrants another look? I know it would fail much below the rated strength.
Bob


majid_sabet


Apr 25, 2008, 12:57 PM
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I am sorry boys but, those biners are loaded from several directions and the main tension is not along the axis line where it should be.

Edit to add; since his biner failed while slacking and not in climbing, this could also prove that notch on the gate did not engaged with the pin as I had been saying it in the LAB.


correct loading ( A)
Multi directional loading ( B)






(This post was edited by majid_sabet on Apr 25, 2008, 2:10 PM)


majid_sabet


Apr 25, 2008, 1:04 PM
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epoch wrote:
That webbing has a rating of about 5000 lbf/22.2kN. The caribiner around 5395lb/24kN.

Depending on how it was tensioned it may have been crossloaded. But since we can only assume as to how the system was rigged we can only assume the reasons it may have broke. Being a bootied biner also, as you stated, brings into question of the history of that particular biner. Maybe one of the engineering types can provide a better analysis of the possibility of failure based on where the biner broke.

I use an exclusive set of caribiners for slacklining and purchased them just for the set up that I have.

Most webbings are rated around 4000 to 4400 lbs. Generally, you rate them about 18 KN ( with knot).


jakedatc


Apr 25, 2008, 1:40 PM
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majid_sabet wrote:
I am sorry boys but, those biners are loaded from several directions and the main tension is not along the axis line where it should be.

Edit to add; since his biner failed while slacking and not in climbing, this could also prove that notch on the gate may not did not engaged with the pin as I had been saying in the LAB.


correct loading ( A)
Multi directional loading ( B)

[IMG]http://b.imagehost.org/0623/loaded.jpg[/IMG]

[IMG]http://b.imagehost.org/0623/load1_2.jpg[/IMG]

Multi directional loaded and crossloaded are 2 different things. Crossloaded in my experience is the spine or gate perpendicular to the load.

It looks like a classic open gate as Jim said.. Why they wouldn't be using lockers on a slack line to prevent just that isn't smart.. at least have non lockers op/opposed

from a standard D biner
Strength major axis open 9 kilonewtons


(This post was edited by jakedatc on Apr 25, 2008, 1:42 PM)


SantaCruzClimber


Apr 25, 2008, 2:36 PM
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After reading this thread im starting to wonder how safe my line is, i always imagined should a biner fail on me, the friction of the line wrapping so many times would slow it enough that i wouldent get pegged in the head. I do not use lockers.

Any tips on rigging, or common mistakes i should have in mind ? Readings?


endercore


Apr 25, 2008, 2:57 PM
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The webbing I use as an anchor for my line broke the other day.

thankfully I had some excess line friction wrapped around the tree so that when my anchor snapped I didn't have the whole system snapping back towards me.


for anyone that is interested- the webbing most probably broke from rubbing against the bark of the tree it was around.


irregularpanda


Apr 25, 2008, 3:09 PM
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SantaCruzClimber wrote:
I do not use lockers.

Any tips on rigging, or common mistakes i should have in mind ? Readings?

Use lockers, also epoch said this earlier "I use an exclusive set of caribiners for slacklining and purchased them just for the set up that I have. " Which is a great idea, and angry said to use steel biners......... which lets you load your carabiner from several directions.


majid_sabet


Apr 25, 2008, 3:35 PM
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SantaCruzClimber wrote:
After reading this thread im starting to wonder how safe my line is, i always imagined should a biner fail on me, the friction of the line wrapping so many times would slow it enough that i wouldent get pegged in the head. I do not use lockers.

Any tips on rigging, or common mistakes i should have in mind ? Readings?

By just looking at the way you guys rig, there are so many problems with your systems and looks like most of you follow each other on wrong rigging tips.Now,even if you use locking biner, you are still applying tensions from several point to the biners. When you are using a fat knot on that webbing to attach it to biner. you are applying tensions and forces away from the axis line. You could tie your webbing to a steel rap ring then use the rap ring to connect it to biner.This way, you are using a smaller diameter attachment point and the load stays in the axis line.

Also, each leg of the anchor should have less than 120 degree when attached to biner. Whatever you do, make sure the tension is not loading the biner from corners as I pointed earlier.


crazy_fingers84


Apr 25, 2008, 3:37 PM
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the biner that broke here was on the non-tightening side of the line. a was set up to always be on the non-tightening side because there is pretty much a permanent girth-hitch on the carabine. nothing slowed it down when it failed at this point. there is so much tension in some slackline systems that i think the even if only a piece of webbing hit you, it could do some damage to you. . . let alone a piece of flying carabiner.
i will say that the picture majid showed of the slackline is exactly how this one was set up. this is a really standard way to set up a slackline, and i have never really had much concern about it loading a carabiner incorrectly. i guess climbing gear sometimes carries a misconception about being unbreakable. . .
doesnt seem like it would be a problem to load it multi-directionally as long as the biner is a few feet away from the anchoring point. when the biner is loaded really close to the anchor, the direction of pull is outward at two points in addition to the direction of pull from the slackline.


petsfed


Apr 25, 2008, 3:51 PM
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crazy_fingers84 wrote:
the biner that broke here was on the non-tightening side of the line. a was set up to always be on the non-tightening side because there is pretty much a permanent girth-hitch on the carabine. nothing slowed it down when it failed at this point. there is so much tension in some slackline systems that i think the even if only a piece of webbing hit you, it could do some damage to you. . . let alone a piece of flying carabiner.

I had an anchor sling fail on me a few years ago. The carabiner that flew thirty feet into my knee only grazed me, but it left one hell of a bruise. I doubt I'd be walking today if it had hit me dead on.

To the topic at hand: the stretch-relax cycles on a slackline will occasionally open a carabiner (I've watched this a few too many times to doubt it) so I don't walk on my line until every carabiner is a locker screwed shut. My tightening system is different, but it is backed up by the tightening system you can see in majid's post, which is rigged entirely with lockers in my system (and with an overhand on a bight instead of the clove hitch that m_s has).

Judging by the photo, this looks like an open gate failure, so replace the crabs in that location with lockers (I've found autolockers won't unscrew with vibration of the line, so that may be worth considering).


majid_sabet


Apr 25, 2008, 3:59 PM
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petsfed wrote:
crazy_fingers84 wrote:
the biner that broke here was on the non-tightening side of the line. a was set up to always be on the non-tightening side because there is pretty much a permanent girth-hitch on the carabine. nothing slowed it down when it failed at this point. there is so much tension in some slackline systems that i think the even if only a piece of webbing hit you, it could do some damage to you. . . let alone a piece of flying carabiner.

I had an anchor sling fail on me a few years ago. The carabiner that flew thirty feet into my knee only grazed me, but it left one hell of a bruise. I doubt I'd be walking today if it had hit me dead on.

To the topic at hand: the stretch-relax cycles on a slackline will occasionally open a carabiner (I've watched this a few too many times to doubt it) so I don't walk on my line until every carabiner is a locker screwed shut. My tightening system is different, but it is backed up by the tightening system you can see in majid's post, which is rigged entirely with lockers in my system (and with an overhand on a bight instead of the clove hitch that m_s has).

Judging by the photo, this looks like an open gate failure, so replace the crabs in that location with lockers (I've found autolockers won't unscrew with vibration of the line, so that may be worth considering).


You should always warp a T shirt over hardware that are under massive tension. I also had seen riggers leave some rope or webbing to hang after the biner. This hanging rope (cord, sling, ..) causes the webbing or cord that is under tension not to fly if system fails.

Other option is to start the knot few feet away from the end and attach the end to a seperate anchor


(This post was edited by majid_sabet on Apr 25, 2008, 4:02 PM)


jcrew


Apr 25, 2008, 4:02 PM
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like was said, probably an open-gate situation.

now, i don't know if people like using climbing gear for lines, but the state-of-the- highline rigs use steel rigging shackles and industrial span-sets/choke rings. the is no climbing gear in the picture except for bolt hangers...the biners are steel screw gate ovals, like angry said.


jt512


Apr 25, 2008, 4:14 PM
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endercore wrote:
The webbing I use as an anchor for my line broke the other day.

thankfully I had some excess line friction...

Thankfully, it wasn't a highline.

Jay


jt512


Apr 25, 2008, 4:17 PM
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Why do you guys use carabiners instead of quick links, which can be wrench tightened.

Jay


petsfed


Apr 25, 2008, 4:34 PM
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jt512 wrote:
Why do you guys use carabiners instead of quick links, which can be wrench tightened.

Jay

Too cheap to go to that much trouble for a low line.

I know, that's a terrible reason, but I'm much more likely to get injured by falling off the line than if the line fails. I've never had a failure when anyone was on the line, but I guess there's a first time for everything. I'm in the process of reworking my system in favor of steel equipment, but its expensive and time consuming, so in the mean time I just check my gear more often than I used to.

Also, I've heard about the threads on quicklinks deforming under high load so that they're impossible to open again, and I don't like being forced to cut apart a system under load. Frankly, that seems needlessly reckless. Finally, the scale of a full sized oval is what makes the system go. Most quicklinks I've encountered are too small to use in the same way that I use the carabiners, and unless somebody can suggest a good system that uses only quicklinks, its not worth the somewhat dangerous experimental period as I figure out what works.

n.b. I only rig lowlines. The tallest I've ever rigged had one end 5 feet up, because the area was sloped and we'd bottom out otherwise. The other end was about 3 feet up. I'm not even going to consider a high line until I've had a chance to walk a few and learn what works best in that situation.


(This post was edited by petsfed on Apr 25, 2008, 4:36 PM)


Partner slacklinejoe


Apr 25, 2008, 8:01 PM
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jt512 wrote:
Why do you guys use carabiners instead of quick links, which can be wrench tightened.

Jay
Quicklinks are usually too narrow to allow clean loading of 1" webbing unless you get the very large ones. This especially becomes problematic if you are making a primitive tensioning system trying to use it as a makeshift pulley. In addition you still have the issue of having to manually thread everything instead of clipping or carrying a wrench every time you setup. If you were to make that trade off 50kn rap rings would be a better option.

That said, steel carabiners are an excellent compromise as they offer higher strength as well as the convenience of clipping and they are even lower friction than aluminum (according to the SAR reports I've read). Most people however aren't willing to dedicate such spendy equipment.

Tri-loading and not checking gates are the most common reason for slackline biner failure - and those are really caused by inattention or insufficent knowledge on the rigger's part making more of a human error issue.

I agree with Jim, this looks like an open gate failure. Most likely it was an old biner with a stickey gate, it wasn't fully closed when loaded and thus it failed, probably even at it's rated open strength.


(This post was edited by slacklinejoe on Apr 27, 2008, 2:17 PM)


majid_sabet


Apr 27, 2008, 10:05 AM
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slacklinejoe wrote:
jt512 wrote:
Why do you guys use carabiners instead of quick links, which can be wrench tightened.

Jay
Quicklines are usually too narrow to allow clean loading of 1" webbing unless you get the very large ones. This especially becomes problematic if you are making a primitive tensioning system trying to use it as a makeshift pulley. In addition you still have the issue of having to manually thread everything instead of clipping or carrying a wrench every time you setup. If you were to make that trade off 50kn rap rings would be a better option.

That said, steel carabiners are an excellent compromise as they offer higher strength as well as the convenience of clipping and they are even lower friction than aluminum (according to the SAR reports I've read). Most people however aren't willing to dedicate such spendy equipment.

Tri-loading and not checking gates are the most common reason for slackline biner failure - and those are really caused by inattention or insufficent knowledge on the rigger's part making more of a human error issue.

I agree with Jim, this looks like an open gate failure. Most likely it was an old biner with a stickey gate, it wasn't fully closed when loaded and thus it failed, probably even at it's rated open strength.

my $20 says that even due biner failed due to an open gate, what really caused the gate to fail was side loading the biner which caused the elbow to open up allowing gate to miss the locking notch.


petsfed


Apr 27, 2008, 10:49 AM
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majid_sabet wrote:
slacklinejoe wrote:
jt512 wrote:
Why do you guys use carabiners instead of quick links, which can be wrench tightened.

Jay
Quicklines are usually too narrow to allow clean loading of 1" webbing unless you get the very large ones. This especially becomes problematic if you are making a primitive tensioning system trying to use it as a makeshift pulley. In addition you still have the issue of having to manually thread everything instead of clipping or carrying a wrench every time you setup. If you were to make that trade off 50kn rap rings would be a better option.

That said, steel carabiners are an excellent compromise as they offer higher strength as well as the convenience of clipping and they are even lower friction than aluminum (according to the SAR reports I've read). Most people however aren't willing to dedicate such spendy equipment.

Tri-loading and not checking gates are the most common reason for slackline biner failure - and those are really caused by inattention or insufficent knowledge on the rigger's part making more of a human error issue.

I agree with Jim, this looks like an open gate failure. Most likely it was an old biner with a stickey gate, it wasn't fully closed when loaded and thus it failed, probably even at it's rated open strength.

my $20 says that even due biner failed due to an open gate, what really caused the gate to fail was side loading the biner which caused the elbow to open up allowing gate to miss the locking notch.

Which is no doubt exacerbated by the often unpredictable stretch-relax cycles in a slack line. I doubt it is completely poor sling placement, although I use ovals to counteract that.


ja1484


Apr 27, 2008, 12:00 PM
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jt512 wrote:
Why do you guys use carabiners instead of quick links, which can be wrench tightened.

Jay


The question I usually pose is "why do you guys slackline, because it's not climbing and therefore I couldn't give a crap about it?"

But then, I guess some people out there have fun slacklining. If they want, I guess.


jt512


Apr 27, 2008, 12:19 PM
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ja1484 wrote:
jt512 wrote:
Why do you guys use carabiners instead of quick links, which can be wrench tightened.

Jay


The question I usually pose is "why do you guys slackline, because it's not climbing and therefore I couldn't give a crap about it?"

But then, I guess some people out there have fun slacklining. If they want, I guess.

I should have prefaced my question with, "The lameness of the activity notwithstanding...."

Jay


funkystumpy


Apr 27, 2008, 7:09 PM
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jt512 wrote:
ja1484 wrote:
jt512 wrote:
Why do you guys use carabiners instead of quick links, which can be wrench tightened.

Jay


The question I usually pose is "why do you guys slackline, because it's not climbing and therefore I couldn't give a crap about it?"

But then, I guess some people out there have fun slacklining. If they want, I guess.

I should have prefaced my question with, "The lameness of the activity notwithstanding...."

Jay

If it is so lame then why are you spending your time perusing the slackline forums? Do you two look for ways to put other people's interests down? To me that is worse than spending time on a "lame" activity.

~Funky


jt512


Apr 27, 2008, 7:19 PM
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Re: [funkystumpy] SLACKLINE FAILURE! ! ! [In reply to]
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funkystumpy wrote:
jt512 wrote:
ja1484 wrote:
jt512 wrote:
Why do you guys use carabiners instead of quick links, which can be wrench tightened.

Jay


The question I usually pose is "why do you guys slackline, because it's not climbing and therefore I couldn't give a crap about it?"

But then, I guess some people out there have fun slacklining. If they want, I guess.

I should have prefaced my question with, "The lameness of the activity notwithstanding...."

Jay

If it is so lame then why are you spending your time perusing the slackline forums? Do you two look for ways to put other people's interests down? To me that is worse than spending time on a "lame" activity.

Try and follow along, Einstein.

Jay


chalkfree


Apr 27, 2008, 7:28 PM
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Re: [jt512] SLACKLINE FAILURE! ! ! [In reply to]
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At what point did we all decide not to play nice?

Anyhow, seems like the method of failure is pretty obvious, however simpler solutions are available.

One could for instance tape the gates shut at the nose. But I'm planning on doing any such thing. The reason I feel that all these precautions are a bit over the top is the scenario here, a 250+ lbs person on a line tightened with a 5:1 pulley is just begging to fail. Majid as silly as he sometimes is is right about looking at the degree of the angle formed, but he's looking in the wrong spot, he ought to be looking at the angle in the center of the line, where with a big fella and a tight line the breaking strength of our gear can be exceeded pretty fast.

On a highline this would of course be a bit different, but for my everyday slackline I'm only worried about failure involving over-tensioning.


jt512


Apr 27, 2008, 7:38 PM
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Re: [chalkfree] SLACKLINE FAILURE! ! ! [In reply to]
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chalkfree wrote:
At what point did we all decide not to play nice?

When some hypersensitive idiot couldn't recognize a joke.

Jay


ja1484


Apr 27, 2008, 8:11 PM
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The internet is serious bidness.


taydude


Apr 27, 2008, 8:20 PM
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How tight was that thing that it would whip at the slacker?! I've got a sort of shitty setup that my mom bought me for christmas. So it doesn't have carabiners just a ratchet and a friction camming type device you're supposed to use to take the ratchet off the line. Well going by their instructions I set it up and first walk the cam fails and i hit the ground. No gun shot though and no swollen ankle.


fitzontherocks


Apr 27, 2008, 8:24 PM
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Re: [majid_sabet] SLACKLINE FAILURE! ! ! [In reply to]
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majid_sabet wrote:
By just looking at the way you guys rig, there are so many problems with your systems and looks like most of you follow each other on wrong rigging tips.

You're the first and only person to show a rigged setup.


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Apr 27, 2008, 8:34 PM
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taydude wrote:
Well going by their instructions I set it up and first walk the cam fails and i hit the ground.
Just a hunch but it sounds like you loaded the cam buckle backwards, even if it was some weird hardware failure I'm sure if you contact them they could get it fixed for you and clear up any issues you might have.


petsfed


Apr 27, 2008, 9:30 PM
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Re: [chalkfree] SLACKLINE FAILURE! ! ! [In reply to]
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chalkfree wrote:
The reason I feel that all these precautions are a bit over the top is the scenario here, a 250+ lbs person on a line tightened with a 5:1 pulley is just begging to fail. Majid as silly as he sometimes is is right about looking at the degree of the angle formed, but he's looking in the wrong spot, he ought to be looking at the angle in the center of the line, where with a big fella and a tight line the breaking strength of our gear can be exceeded pretty fast.

On a highline this would of course be a bit different, but for my everyday slackline I'm only worried about failure involving over-tensioning.

The mechanical advantage has no impact on the breaking strength of the line, realistically. Its not like you'd load the anchor with only 250+ or so if you used a 1:1 system, its the same no matter what tightening system you use. I use an (ideally) 9:1 system and we've had 300+ pounders on the line without failure. The key was that no gates ever opened up and we had a very simple tie off that stretched a bit.

Next warm day I'll take some pictures and post up.


taydude


Apr 27, 2008, 9:43 PM
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Re: [slacklinejoe] SLACKLINE FAILURE! ! ! [In reply to]
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lol no it's loaded properly but bouncing made the spring loading cam piece give way or the friction was not enough to hold the tension. either way im not too concerned as i'm going to cut the webbing off of the gear it came with and buy some biners soon.


funkystumpy


Apr 28, 2008, 10:16 AM
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jt512 wrote:
chalkfree wrote:
At what point did we all decide not to play nice?

When some hypersensitive idiot couldn't recognize a joke.

Jay

I apologize for not recognizing some joke that my sense of humor/knowledge base didn't pick up on, but there was no need to call me a hypersensitive idiot. I have seen far too many posts by you and [edit: jal1484], where you slam someone for not much reason at all or for something that you two could have very easily ignored.


(This post was edited by funkystumpy on Apr 28, 2008, 10:40 AM)


jt512


Apr 28, 2008, 10:26 AM
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Re: [funkystumpy] SLACKLINE FAILURE! ! ! [In reply to]
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funkystumpy wrote:
jt512 wrote:
chalkfree wrote:
At what point did we all decide not to play nice?

When some hypersensitive idiot couldn't recognize a joke.

Jay

I apologize for not recognizing some joke that my sense of humor/knowledge base didn't pick up on, but there was no need to call me a hypersensitive idiot. I have seen far too many posts by you and jt512, where you slam someone for not much reason at all or for something that you two could have very easily ignored.

Are you sure there's no reason to call you a hypersensitive idiot?

Jay


funkystumpy


Apr 28, 2008, 10:38 AM
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jt512 wrote:
funkystumpy wrote:
jt512 wrote:
chalkfree wrote:
At what point did we all decide not to play nice?

When some hypersensitive idiot couldn't recognize a joke.

Jay

I apologize for not recognizing some joke that my sense of humor/knowledge base didn't pick up on, but there was no need to call me a hypersensitive idiot. I have seen far too many posts by you and jt512, where you slam someone for not much reason at all or for something that you two could have very easily ignored.

Are you sure there's no reason to call you a hypersensitive idiot?

Jay

Yeah, pretty sure. I am also pretty sure that I don't really feel like wasting my time on a stupid argument with you. Adios


dynosore


Apr 28, 2008, 10:42 AM
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Steel biners: a few extra bucks
Hospital bills: thousands

Not a hard choice....


live2climb


Apr 28, 2008, 10:58 AM
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dynosore wrote:
Steel biners: a few extra bucks
Hospital bills: thousands

Not a hard choice....

wrong steel can break as well my freind
more like
setting up a line with hevel mettle = death
setting up a line with soft points slack hitches and nothing that is not webbing = some one who know how to set up a slack line = do your homework


funkystumpy


Apr 28, 2008, 11:04 AM
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Back to OP:
I think Majid has a good point about wrapping towels or t-shirts around any hardware being used to help prevent projectiles.


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Apr 28, 2008, 11:22 AM
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live2climb wrote:
wrong steel can break as well my freind
more like
setting up a line with hevel mettle = death
setting up a line with soft points slack hitches and nothing that is not webbing = some one who know how to set up a slack line = do your homework

While technically it's true that steel can break I've yet to hear of a single instance where a slackline has broken a steel carabiner. Even the cross load strength of steel is usually higher than the webbing strength.

I have however received lots of mentions of soft pointing destroying the lines via nylon on nylon friction. Most folks rely on prussic style techniques to hold the line, which works on relatively small lines but can easily damage the line on tighter systems.

Soft pointing is a good skill to learn but it has limitations - many a highline has ended up melted due to soft pointing techniques.

Hard pointing is far more prefered in my books - generally having the line sewn for the gap or using a climbing grade harness buckle to adjust your main line's length to a perfect fit. You may still have hardware in your anchors but no tensioning systems. The main difference is avoiding nylon-on-nylon at all costs while still removing the tensioning system. I've personally melted through a surf line in one day with nylon-on-nylon friction. It actually melts the webbing together in a rather interesting display of physics.

I've actually made some nifty little tools to do just that where you have no nylon-on-nylon, no carabiners and only a couple ounces of metal to do it.


(This post was edited by slacklinejoe on Apr 28, 2008, 11:30 AM)


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Apr 28, 2008, 11:32 AM
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funkystumpy wrote:
Back to OP:
I think Majid has a good point about wrapping towels or t-shirts around any hardware being used to help prevent projectiles.
I can't think that a t-shirt will do much other than obscure checking your rigging. Maybe it would reduce impact or keep shards from flying outwards but I can't think it'd reduce the momentum of parts flinging at your ankles by much. I could totally be wrong on it though, I'm not willing to field test it.

However if you have excess webbing on your main line an extra loop around the tree and a quick mule hitch/trucker's hitch/whatever next to the tensioning system towards the center of the line would give you a "safety" if you screwed something up.


(This post was edited by slacklinejoe on Apr 28, 2008, 11:34 AM)


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Apr 28, 2008, 11:43 AM
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Re: [slacklinejoe] SLACKLINE FAILURE! ! ! [In reply to]
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This is a good reason why I don't slackline, I would hate to lose out on climbing because I injured myself messing around, or got a massive brain injury from flying bits of aluminum.













Plus I suck at it.
dev


petsfed


Apr 28, 2008, 11:49 AM
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The current set up I use has an ellington holding the line tight, then a separate tensioning system to get it tight. I pull the ellington tight and then I can reset the tensioning system. The downside is that it thrashes my line something awful in the area that the webbing stacks. Is it any easier to use regular buckles, or a cam buckle, or am I just gonna have to adjust to a line with melt streaks on it?

My main concern is having a crazy cluster fuck when I go to take the tensioning system off.


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Apr 28, 2008, 12:18 PM
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Do keep in mind, I use techniques that aren't widely adopted, so it's not likely you'll see them used elsewhere. I generally dislike using carabiners in my systems due to the frictions involved and the risk they might end up in my climbing pile by accident (yes, you can mark them, but stuff happens).

If you are using a technique of tensioning the line that essentially uses a line grab of sorts (prussic or cam buckle etc) to connect the tensioning system to the main line it frees you up to use different techniques to secure the main line to the tree and easily remove the tensioning system afterwards.

If your sling accomodates a cam buckle or harness buckle you can pull the line tight, then secure the main line to said buckle, then release and remove the tensioning system.

Harness buckles require a bit more fiddling (not much) to get double backed on the main line and are pretty much bomber as they aren't likely to damage the webbing or break due to their strength (4,000lbs).

Cam buckles offer more convenience since you basically pull the line tight, give the slack coming out of the cam buckle a quick yank to secure it and your good to start removing your tensioning system. The trade off is cam buckles do have teeth that can leave marks on the line in some situations but it is usually very mild. They are also not usually as strong as full grade harness buckles but they are usually strong enough for any lowline use (2,200 lbs or 3,300lbs). Either way, it's only a couple bucks to test them out and if rigged properly they should produce zero twists in the system.

The photo below will give you an idea of the slings and how it adapts to the line.

This is what I use as a rodeo line but you can set up the tensioning system on a seperate sling allowing you to use whatever you want (pulleys, carabiners, ratchets, a truck) and then easily remove the tensioning system.


(This post was edited by slacklinejoe on Apr 28, 2008, 12:24 PM)


majid_sabet


Apr 28, 2008, 12:41 PM
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Let me ask a question from our slaking experts;

if you have 200 lbs slacking dude standing in the middle of a super tight 30 feet long piece of webbing with a MA ranging from 5:1 to 9:1 (whatever you normally use).

How much forces do you think your anchors are getting?





(This post was edited by majid_sabet on Apr 28, 2008, 12:43 PM)


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Apr 28, 2008, 12:45 PM
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Re: [majid_sabet] SLACKLINE FAILURE! ! ! [In reply to]
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majid_sabet wrote:
How much forces do you think your anchors are getting?
With your diagram - infinity.
You missed one of the parameters - sag - how much the line dips in the middle with the slacker standing on it.

If you assume it's a nice and tight line with 1' of sag in the middle the line load would be 1503.33lbs of tension. 1.5' would be 1000lbs. It would be the same load regardless of tensioning system and "perceived" pre-tension amount - the sag tells the real story.

Slackline Force Calculator


(This post was edited by slacklinejoe on Apr 28, 2008, 12:47 PM)


petsfed


Apr 28, 2008, 1:32 PM
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majid_sabet wrote:
Let me ask a question from our slaking experts;

if you have 200 lbs slacking dude standing in the middle of a super tight 30 feet long piece of webbing with a MA ranging from 5:1 to 9:1 (whatever you normally use).

How much forces do you think your anchors are getting?


[IMG]http://a.imagehost.org/0221/web.jpg[/IMG]

I don't feel like doing the integrals neccesary to tell you, but its not a simple answer. The slackline force calculator doesn't really answer it completely either, since it is actually a very complicated system. You've got what works out to be a semi-damped harmonic oscillator in 3 dimensions, with different damping terms in each direction, as well as a green's-function-style force term from the person on the line. I've been meaning to assemble a general equation based on a variety of parameters to find out, but it is so complicated that such a general equation would be a worthwhile master's thesis.


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Apr 28, 2008, 2:06 PM
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petsfed wrote:
majid_sabet wrote:
Let me ask a question from our slaking experts;

if you have 200 lbs slacking dude standing in the middle of a super tight 30 feet long piece of webbing with a MA ranging from 5:1 to 9:1 (whatever you normally use).

How much forces do you think your anchors are getting?


[IMG]http://a.imagehost.org/0221/web.jpg[/IMG]

I don't feel like doing the integrals neccesary to tell you, but its not a simple answer. The slackline force calculator doesn't really answer it completely either, since it is actually a very complicated system. You've got what works out to be a semi-damped harmonic oscillator in 3 dimensions, with different damping terms in each direction, as well as a green's-function-style force term from the person on the line. I've been meaning to assemble a general equation based on a variety of parameters to find out, but it is so complicated that such a general equation would be a worthwhile master's thesis.


In reply to:
The mechanical advantage has no impact on the breaking strength of the line, realistically. Its not like you'd load the anchor with only 250+ or so if you used a 1:1 system, its the same no matter what tightening system you use. I use an (ideally) 9:1 system and we've had 300+ pounders on the line without failure. The key was that no gates ever opened up and we had a very simple tie off that stretched a bit.

A single person pulling on a 3:1 MA could apply 150 lbs of tension on an anchor with one hand. Same person with a 9:1 MA can put over 450 lbs of tension. A 200 ponder standing in the middle of 30 feet of webbing under 9:1 tension can put great deal of stress on biners if not carefully rigged.


(This post was edited by majid_sabet on Apr 28, 2008, 2:33 PM)


ja1484


Apr 28, 2008, 2:39 PM
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jt512 wrote:
funkystumpy wrote:
jt512 wrote:
chalkfree wrote:
At what point did we all decide not to play nice?

When some hypersensitive idiot couldn't recognize a joke.

Jay

I apologize for not recognizing some joke that my sense of humor/knowledge base didn't pick up on, but there was no need to call me a hypersensitive idiot. I have seen far too many posts by you and jt512, where you slam someone for not much reason at all or for something that you two could have very easily ignored.

Are you sure there's no reason to call you a hypersensitive idiot?

Jay





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Apr 28, 2008, 3:05 PM
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majid,

With all due respect, your questions (and your answers) show you don't slackline much.

Most of these folks using 3:1's are using carabiners. The effective MA is actually only 1.75:1 to 1.5:1 due to friction. Even the 9:1 setups using multipliers often only yield 6.1:1 effective MA or less. Generally speaking you have to get quite a few brawn lads to generate a dangerously high load unless you are resorting to methods such as using vehicles to tighten things up.

The elasticitiy effect of webbing under tension greater than 400lbs allows a shock dampening effect that basically saves our buns by spreading the force of dynamic moves over a longer time and thus reducing peak forces in the system. That allows you to calculate for a static system and a lot of the time your pre-tension load will be very close to the load that you have when on it when walking - it's wierd but it's been tested over and over.

Also, the whole sag thing I mentioned is critical. Not just as a load thing but for practical walking applications. If you get a line too tight it's basically no fun to walk, it's twitchy and violent. That and the line's elasticity makes it very difficult to get the line tighter than a certain load as it just keeps stretching when the loads get high, much like a climbing rope - it'll reach plastic deformation and stretch pretty massive amounts before you'll actually break it.


petsfed


Apr 28, 2008, 3:33 PM
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majid_sabet wrote:
petsfed wrote:
majid_sabet wrote:
Let me ask a question from our slaking experts;

if you have 200 lbs slacking dude standing in the middle of a super tight 30 feet long piece of webbing with a MA ranging from 5:1 to 9:1 (whatever you normally use).

How much forces do you think your anchors are getting?


[IMG]http://a.imagehost.org/0221/web.jpg[/IMG]

I don't feel like doing the integrals neccesary to tell you, but its not a simple answer. The slackline force calculator doesn't really answer it completely either, since it is actually a very complicated system. You've got what works out to be a semi-damped harmonic oscillator in 3 dimensions, with different damping terms in each direction, as well as a green's-function-style force term from the person on the line. I've been meaning to assemble a general equation based on a variety of parameters to find out, but it is so complicated that such a general equation would be a worthwhile master's thesis.


In reply to:
The mechanical advantage has no impact on the breaking strength of the line, realistically. Its not like you'd load the anchor with only 250+ or so if you used a 1:1 system, its the same no matter what tightening system you use. I use an (ideally) 9:1 system and we've had 300+ pounders on the line without failure. The key was that no gates ever opened up and we had a very simple tie off that stretched a bit.

A single person pulling on a 3:1 MA could apply 150 lbs of tension on an anchor with one hand. Same person with a 9:1 MA can put over 450 lbs of tension. A 200 ponder standing in the middle of 30 feet of webbing under 9:1 tension can put great deal of stress on biners if not carefully rigged.

I must be brief, since I have to go to work shortly.

The tension of the line is not dependent on what system you use to pull it tight, just how tight you managed to pull it. The sag of the line (as joe put it) is described by the hyperbolic cosine of a term proportional to the inverse of the horizontal tension. Put most simply, its a hyperbolic function of the inverse of the force pulling on either tree. In other words, a line of a given tension will hang the same whether there's a tightening system pulling it tight, or if its just statically anchored at either end.

Imagine a spring scale attached to one end of a string that has been tied to the floor. As you pull up on the string, the spring scale will show how much force you're pulling on the string with. Suppose you push on the string, perpendicular to its length with some fixed deflection force. The measurement on the scale will change some noticeable amount. Now imagine that you rig something similar, but you use a tightening system (say a 3:1) to get the same force measurement on the spring scale, then you apply the same deflection force. The change in measurement on the spring scale will be the same.

To sum up, no matter how you tighten the line, if its the same tension, a given deflection force will increase the line tension by the same amount. If this were not the case, hauling systems would not work because increasing mechanical advantage would quickly blow out anchors.

Saying a system has a 3:1 mechanical advantage means two things: first, in the absence of friction, it means that the force that you pull on the rope with is multiplied by three. Second, it means that for every 3 feet of rope you pull out of the system, it pulls only 1 foot out of the line. Since work is force times distance, you can see that it saves no work to do it this way. It does decrease the force necessary to accomplish any given task though, which is significant.


crazy_fingers84


Apr 28, 2008, 3:39 PM
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  i definitely agree with the notion that the mechanical advantage of a pulley system is drastically reduced as a result of friction. the typical way to overcome this problem is to get more people to pull on the line. i have set up lines before with my truck and had them so tight that i have broken tubular webbing (never completely, it only tore about half way through). when i was done slackining i took the line down i saw what had happened. since that day i have been very cautious of my slackline failing. when i my friend told me what happened to her, it hit close to home. . .
thankfully nobody was hurt in this instance, but i think a lot of people out there can take something from this situation.
i guess when there is no slack in the webbingg, it is no longer a slackline. . . it requires a different rigging then a conventional slackline. i dont understand how we can predict the amount of force being put on a slackline with out evaluating each line independently. it seems like there are an infinite number of variables that could drastically change those calculations depending on how the rigger set the system up. but i am not a math person, so i will leave it to those guys to argue logistics.
in the case of this accident the line was abnormally tight. it would have helped to do a lot of things different in this situation. the two red flags here are the bootied biner, and the ultimate reason for failure being an open gate. CHECK YOUR GATES FOLKS! weird things happen in the real world, gates open. . . whatever. fuck buying steel carabiners for a lowline, that is overkill. i do see the utility in purchasing a locker for this reason.
usually when i set my line up, i pull it tight by myself. this how i like it, a dynamic line with a lot of movement. . . which is what i think makes slacklining fun anyway. and to answer the question of why participate in a lame sport like slackling, well i do it because it forces me to concentrate very intensely on the activity at hand. this is something i am always striving for when i am climbing, and it is refreshing to chase this feeling in a new venue. . .


majid_sabet


Apr 28, 2008, 4:22 PM
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crazy_fingers84 wrote:
i definitely agree with the notion that the mechanical advantage of a pulley system is drastically reduced as a result of friction. the typical way to overcome this problem is to get more people to pull on the line. i have set up lines before with my truck and had them so tight that i have broken tubular webbing (never completely, it only tore about half way through). when i was done slackining i took the line down i saw what had happened. since that day i have been very cautious of my slackline failing. when i my friend told me what happened to her, it hit close to home. . .
thankfully nobody was hurt in this instance, but i think a lot of people out there can take something from this situation.
i guess when there is no slack in the webbingg, it is no longer a slackline. . . it requires a different rigging then a conventional slackline. i dont understand how we can predict the amount of force being put on a slackline with out evaluating each line independently. it seems like there are an infinite number of variables that could drastically change those calculations depending on how the rigger set the system up. but i am not a math person, so i will leave it to those guys to argue logistics.
in the case of this accident the line was abnormally tight. it would have helped to do a lot of things different in this situation. the two red flags here are the bootied biner, and the ultimate reason for failure being an open gate. CHECK YOUR GATES FOLKS! weird things happen in the real world, gates open. . . whatever. fuck buying steel carabiners for a lowline, that is overkill. i do see the utility in purchasing a locker for this reason.
usually when i set my line up, i pull it tight by myself. this how i like it, a dynamic line with a lot of movement. . . which is what i think makes slacklining fun anyway. and to answer the question of why participate in a lame sport like slackling, well i do it because it forces me to concentrate very intensely on the activity at hand. this is something i am always striving for when i am climbing, and it is refreshing to chase this feeling in a new venue. . .


it is funny that you guys thank god that no one got hurt but if the same person fell and became paralyzed, then all of you were back in here with photos and diagrams, physic and math calculation with KN poping from every angle analyzing the fuc* out of every pieces of gear involved with the incident.

My suggestion is that you slackers should analyze your rigging behaviors and come up with a safety guidelines for you own rig. Seriously think about the forces and failures before someone get hurt.


(This post was edited by majid_sabet on Apr 28, 2008, 4:25 PM)


shaun_the_conqueror


Apr 28, 2008, 4:24 PM
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I would be very skeptical of any of the numbers that little force generator puts out and I wouldn't suggest relying on them, especially if you're going to rig a highline. Mainly because I do not know how the calculation is being made, what variables are involved, and who the person is who came up with it and whether or not they are credible in the first place.

One thing I want to point out for anyone who is rigging a primitive system, is that you can easily avoid flying gear in the case that you have biner failure, anchor failure, or pulley failure. In this particular case the easiest thing one could have done to prevent a flying biner, was to tie the loose end of the slackline itself to the anchor. All tension would have been lost, hoewever there would not have been any flying gear. The same thing could also be done if you were to have a pulley in place of the primitive system.

Generally slackline anchor rigging relies on tri-loading a carabiner on both ends. This isn't really a good idea since carabiners aren't designed for this. 2 solutions which still involve tri-loading to prevent anchor failure would be, decrease the angle created when tri-loading a biner, and maybe use a steel carabiner as others have suggested.

My personal solution to prevent tri-loading is this.


I use 11mm static rope threaded through 1" webbing. I always tie off the slackline to the anchor incase something in the pulley breaks or a biner decides its had its final day. A couple things that I've changed, is that there is 2 rap rings on each anchor, and I use an SBI pulley block instead of the primitive system or shitty ass ratchets that are way more prone to failure then the primitive system.

Reasons for using this:
1) Ultimate adjustable tree slings... just make your anchor 10ft long.
2) Anchor is now bomber as hell. You can replace the aluminum biners with steel if you wish.
3) The line is ALWAYS perfectly flat if you use line lockers with the rap ring technique.

What you need to watch out for if you adopt this method:
1) Make sure you inspect your biners that are in contact with the rap rings if you use steel rap rings.
2) make sure your clove hitch stacks properly or you're gonna lose all tension first step on the line.
3) Inspect your webbing that the 11mm is threaded through for damage so you can replace it and save your 11mm from being messed up.

I've been using the same anchor system for almost a year now. if you use proper tree protection, you won't have to ever replace the webbing.


Partner slacklinejoe


Apr 28, 2008, 4:45 PM
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I've got a couple issues I'd like to point out with your setup Shaun.

First, putting the carabiner under load where it is being flexed against the tree's bark has been known to push open gates or even break them from the prying load.

Second - Are you sure your method of padding is sufficent? It looks like the left side is just abraiding against the tree but the right side is using the upright stick to protect the tree's bark. Maybe it just blending and is hard to make out on the photo.

Regarding the calculator: it's triometric based. The explainations on how it works is on a link on that page. I based the calculator on Eric Matthes' work. He did a very good job breaking it down on his site, and with his permission I turned it into a web based application. So far the results have been very in line with field tests with dynomometers.


petsfed


Apr 28, 2008, 5:09 PM
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slacklinejoe wrote:
Regarding the calculator: it's triometric based. The explainations on how it works is on a link on that page. I based the calculator on Eric Matthes' work. He did a very good job breaking it down on his site, and with his permission I turned it into a web based application. So far the results have been very in line with field tests with dynomometers.

Its actually a very good first order approximation. Its primary failings are that it doesn't deal with the motion of the slacker, side to side motion, stretch in your tie-off, etc. Since the anchor force goes to infinity at zero sag, the approximation is clearly wrong at that limit. Real forces don't do that. However, the approximation does what its supposed to do, so in that sense it works.


shaun_the_conqueror


Apr 28, 2008, 6:33 PM
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The whole tree is properly protected using branches in the photos posted, you're absolutely right, it is hard to see. I actually don't leave the carabiners resting against the tree because as you stated "the gates can be pushed open" and this is correct. I try and keep the carabiners closer to the rap rings. I use carpet to pad trees when I can, but when circumference of the trees exceeds my 5ft pieces of crapet, I have to resort to using branches. As far as the calculations you use go, I'll have to read more about it. I wouldn't trust a static load fixed in one posistion to assume the whole rigging is safe though.


Partner slacklinejoe


Apr 28, 2008, 6:52 PM
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As mentioned, oned of the limitation of the calculator is dynamic loads. The assumptions of the calculations are listed on that site.

However, as I mentioned above the dynamic (shock absorbing) capabilities of webbing when under loads that let it's elasticity go to work help dampen the effects of jumps and surfing moves etc. Tests have shown normal surfing wiggles the load but overall not as much of an impact as I'd have expected. Jumping right next to the anchor does impact loads but again, I was suprised at how little the loads really were even on lines that "felt" insanely tight.

Oh, and to the infinity issue - your right, you can't measure a load like that using the system - that's because you'd have broken any piece of equipment well before you approach a zero change in deflection on the line. Simply put, as far as I know it's actually impossible to reach that condition using a flexible medium such as rope or webbing, you'll just manage to break it trying to get your preload.

Worth noting - similar physics apply on the "american death triangle" for climbing anchors. As the bottom point's angle gets larger the loads get levered much, much higher - in theory to the same situation of a slackline.


(This post was edited by slacklinejoe on Apr 28, 2008, 7:02 PM)


billcoe_


Apr 29, 2008, 8:17 PM
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No one has mentioned work hardening of the aluminum in the carabiner.

Before it is assumed that the gate was open and then the breakage issue totally dismissed, I think it's worth thinking of the work hardening effect. Take any piece of aluminum and bend it. You can do this for awhile, until it finally snaps. For climbing, biners do not see this repeated cycling and metal movement, at least not to this degree even when aid climbing long routes: however, as this was a dedicated biner to a slackline system, is it not appropriate to ask how many times the line was set up before this carabiner failed. Could be something there.

I wonder if testing can determine the if the malleability of the metal in that carabiner had changed since it was manufactured, and if that may have been due to excessive or repeated load cycling from setting up the slackline repeatedly. Bet Black Diamond would like to take a look at it b4 one of these BD biners - even a bottied one, snaps then hits some poor kid in the temple and kills them.

May I suggest you contact the Black Diamond company and ask if they would like to follow up on this idea and look at the failed piece of equipment? This would be an excellent place to start, as their products, as much as anyone else's, is tested and checked to a high standard before it hits the streets. If nothing else, watching what happened to Hugh Banners company when the family of the dumb son-of-a bitch who died rappelling when he IMPROPERLY used an HB carabiner (and it failed due to his own stupidity and rashness) sued them, I would want to be proactive and look at this if I were with BD.

The life you save with the info gleaned may be your own. Who can say?

Regards to all

Bill


majid_sabet


Apr 29, 2008, 11:56 PM
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billcoe_ wrote:
No one has mentioned work hardening of the aluminum in the carabiner.

Before it is assumed that the gate was open and then the breakage issue totally dismissed, I think it's worth thinking of the work hardening effect. Take any piece of aluminum and bend it. You can do this for awhile, until it finally snaps. For climbing, biners do not see this repeated cycling and metal movement, at least not to this degree even when aid climbing long routes: however, as this was a dedicated biner to a slackline system, is it not appropriate to ask how many times the line was set up before this carabiner failed. Could be something there.

I wonder if testing can determine the if the malleability of the metal in that carabiner had changed since it was manufactured, and if that may have been due to excessive or repeated load cycling from setting up the slackline repeatedly. Bet Black Diamond would like to take a look at it b4 one of these BD biners - even a bottied one, snaps then hits some poor kid in the temple and kills them.

May I suggest you contact the Black Diamond company and ask if they would like to follow up on this idea and look at the failed piece of equipment? This would be an excellent place to start, as their products, as much as anyone else's, is tested and checked to a high standard before it hits the streets. If nothing else, watching what happened to Hugh Banners company when the family of the dumb son-of-a bitch who died rappelling when he IMPROPERLY used an HB carabiner (and it failed due to his own stupidity and rashness) sued them, I would want to be proactive and look at this if I were with BD.

The life you save with the info gleaned may be your own. Who can say?

Regards to all

Bill

Back in my biner gate post in LAB, Dingus posted an research articles from the MTI where two guys did a study on biner's fatigue and stress issues. It is worth reading.


iheartsublime


Jun 8, 2008, 8:22 PM
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WOW!!! thats all that i can say...she is very lucky...i dont know where you got the carabiner from but tape on a carabiner usually means its retired...that might have been it...nice slackline...orange is the shiz!


petsfed


Jun 8, 2008, 8:54 PM
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iheartsublime wrote:
WOW!!! thats all that i can say...she is very lucky...i dont know where you got the carabiner from but tape on a carabiner usually means its retired...that might have been it...nice slackline...orange is the shiz!

NO.

Tape on a carabiner means that the carabiner has tape on it.

There's no universal system to mark gear, no agreed on tape/nail polish/spray paint/goat urine mark that means retired, or slacking only, or master power point for the big red pig.

If tape means "retired", then every piece of metal I own, with exception to 3 carabiners and a big bro, must be retired.

Dumbass.


iheartsublime


Aug 26, 2008, 12:14 PM
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keyword is "might" buddy!

who argues with people in a forum...get a life.


carbonrx8


Aug 26, 2008, 12:41 PM
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iheartsublime wrote:
keyword is "might" buddy!

who argues with people in a forum...get a life.
That was a very snappy and timely comeback.


petsfed


Aug 26, 2008, 2:49 PM
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iheartsublime wrote:
keyword is "might" buddy!

who argues with people in a forum...get a life.

I know this is gonna run contrary to the elan of this site, but please, PLEASE try to refrain from speculating on failure modes when you haven't got the good sense to critically examine your beliefs beforehand.

I'm certain that if the carabiner had been retired from regular use do to concerns about its safety, the OP would've mentioned it (and justly be flamed for being so stupid).

My response, ire and all, was motivated mostly because even a slightest bit of thinking would've revealed the ridiculousness of your statement. Please consider thinking before typing in the future.


iheartsublime


Aug 27, 2008, 6:13 AM
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OK


USnavy


Oct 6, 2008, 2:28 AM
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When a carabiner fails in the closed gate position there is generally a high level of deformation present on the body of the carabiner. Additionally, the pin on the gate or the nose on the carabiner is usually broken off. I see none of theses items present in the pictures, which leads me to believe it was an open gate failure.


shaun_the_conqueror


Oct 6, 2008, 9:17 AM
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I just wanted to point out that I recently retired a biner which I found had a fracture on the gate coming down from the pin. Further more, the very tip of the gate was some what skewed. I outlined the skewed gate and fracture in the images below. Check your gear people! With the tensions and line lengths I use, this fractured gate could have made for a painful time.





jeremy11


Oct 6, 2008, 10:27 AM
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I have seen steel biners break, but that was rigging a 1'000 foot zipline of 1/2" aircraft cable at a canopy tour. We were pulling it up with a tractor and one biner broke when the cable got stuck on a tree branch. Reset and tried again, then another carabiner broke. In one the notch on the gate broke, on the other the hinge pin broke. both were rated to about 30 kN and were quite old and beat up from ropes course building abuse. tri-loading was also a possibility with how it was rigged.

point being, steel biners are pretty bomber.


NJSlacker


Oct 7, 2008, 5:33 PM
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jeremy11 wrote:
both were rated to about 30 kN.

30kN steel? I have 25kN aluminum. My steel is 60kN. You need some real steel biners

jeremy11 wrote:
point being, steel biners are pretty bomber.

that's not the point I got from your story...


jeremy11


Oct 7, 2008, 5:45 PM
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NJSlacker wrote:
jeremy11 wrote:
both were rated to about 30 kN.

30kN steel? I have 25kN aluminum. My steel is 60kN. You need some real steel biners

jeremy11 wrote:
point being, steel biners are pretty bomber.

that's not the point I got from your story...


they are bomber: here is what it took to break them
- old and abused by construction
- low rated for steel biners
(they exist and are on the market right now)
- possible tri-load (I didn't rig that part)
- 1000 feet of 1/2 inch aircraft cable
- pulled under tension by a tractor
- cable ran through a pulley at the top of the 60 foot tower, through a pulley at the bottom of the tower, then to the tractor
- this worked fine until the cable snagged on a tree limb

Point being THIS IS WHAT IT TOOK to break an old, beat up, low rated steel biner!


shaun_the_conqueror


Oct 7, 2008, 5:55 PM
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Note to self:

Check rigging before ever going on a canopy tour...


jeremy11


Oct 7, 2008, 6:09 PM
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shaun_the_conqueror wrote:
Note to self:

Check rigging before ever going on a canopy tour...


this was the tensioning.
the finished product is a pole wrap with three fist grips, multiple guylines, as bomber as it gets and full in accordance with Association for Challenge Course Technology standards.
Its not like the canopy tour is in Costa Rica or anything

Feel free to inspect all you want though.


(This post was edited by jeremy11 on Oct 7, 2008, 6:14 PM)


shaun_the_conqueror


Oct 9, 2008, 9:38 AM
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Well apparently they need to learn a thing or two about inspecting and retiring gear.


dynosore


Oct 9, 2008, 10:01 AM
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Do you drive your car with the motor screaming at 6500 rpm redline constantly? Just because a mechanical component is rated for a certain strength doesn't mean you should constantly load it to the brink! Ever hear of a safety margin? Steel biners are a lot cheaper than broken ankles!


USnavy


Oct 27, 2008, 2:46 AM
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majid_sabet wrote:
I wonder how they guys really stay alive doing what they do.

I took this photo in my gym for reference to point out biner cross loading.

[IMG]http://b.imagehost.org/0621/04-06-07_2000.jpg[/IMG]

[IMG]http://b.imagehost.org/0621/04-06-07_1957.jpg[/IMG]

[IMG]http://b.imagehost.org/0621/04-06-07_1959.jpg[/IMG]

Triaxial loading, not crossloading. Thatís not an example of crossloading.


Forums : Climbing Disciplines : Slacklining

 


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