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Video: Testing FF2 with dyneema
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jliungman


Dec 19, 2012, 1:28 AM
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Video: Testing FF2 with dyneema
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Hi!

I have received video material from some friends and experienced climbing instructors, showing some fairly alarming results concerning the use of knotted dyneema.

http://vimeo.com/41522053

I apologize for the fact that commentary is in Swedish. Iīve uploaded two doodles to try and explain whats going on. (EDIT: Note that this is NOT a static fall, the rope used is DYNAMIC. The rope is tied to the dummy, and to the carabiner shown at the bottom of each sketch.)

The results, in short, show that under heavy but entirely realistic loads (ff 2 with new rope and and test dummy), a new dyneema sling fails completely. This happens when the dyneema is shortened using two techniques which, at least in Scandinavia, are common and taught by instructors.
Any thoughts? To me the results imply that we should avoid knotting dyneema altogether, and use this fantastic material only in full length, stitched slings (like quick draws). At least until we know more about which nylon/dyneema/widths/knots combinations work and which donīt.


(This post was edited by jliungman on Dec 19, 2012, 12:29 PM)
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iknowfear


Dec 19, 2012, 2:44 AM
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Re: [jliungman] Video: Testing FF2 with dyneema [In reply to]
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jliungman wrote:
Hi!

I have received video material from some friends and experienced climbing instructors, showing some fairly alarming results concerning the use of knotted dyneema.

http://vimeo.com/41522053

I apologize for the fact that commentary is in Swedish. Iīve uploaded two doodles to try and explain whats going on.

The results, in short, show that under heavy but entirely realistic loads (ff 2 with new rope and and test dummy), a new dyneema sling fails completely. This happens when the dyneema is shortened using two techniques which, at least in Scandinavia, are common and taught by instructors.
Any thoughts? To me the results imply that we should avoid knotting dyneema altogether, and use this fantastic material only in full length, stitched slings (like quick draws). At least until we know more about which nylon/dyneema/widths/knots combinations work and which donīt.

thanks.

http://dmmclimbing.com/...notting-dyneema-vid/

this can be summed up:
Don't fall on static stuff.

regarding this:
In reply to:
ff 2 with new rope and and test dummy

I can't think of a situation in which a rope is relevant here... do you mean new sling?


(This post was edited by iknowfear on Dec 19, 2012, 2:45 AM)


USnavy


Dec 19, 2012, 3:10 AM
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Re: [jliungman] Video: Testing FF2 with dyneema [In reply to]
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jliungman wrote:
Hi!

I have received video material from some friends and experienced climbing instructors, showing some fairly alarming results concerning the use of knotted dyneema.

http://vimeo.com/41522053

I apologize for the fact that commentary is in Swedish. Iīve uploaded two doodles to try and explain whats going on.

The results, in short, show that under heavy but entirely realistic loads (ff 2 with new rope and and test dummy), a new dyneema sling fails completely. This happens when the dyneema is shortened using two techniques which, at least in Scandinavia, are common and taught by instructors.
Any thoughts? To me the results imply that we should avoid knotting dyneema altogether, and use this fantastic material only in full length, stitched slings (like quick draws). At least until we know more about which nylon/dyneema/widths/knots combinations work and which donīt.
Cool video, but this is not new news, we have known about this forever. Also, it is best not to tie knots in Dyneema slings for a number of reasons.


(This post was edited by USnavy on Dec 19, 2012, 3:11 AM)


njrox


Dec 19, 2012, 6:50 AM
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Re: [jliungman] Video: Testing FF2 with dyneema [In reply to]
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jliungman wrote:
To me the results imply that we should avoid knotting dyneema altogether, and use this fantastic material only in full length, stitched slings (like quick draws).

Yep. I only use dyneema for sling-draws and never knot it.


jliungman


Dec 19, 2012, 11:33 AM
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Re: [iknowfear] Video: Testing FF2 with dyneema [In reply to]
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iknowfear wrote:

this can be summed up:
Don't fall on static stuff.

regarding this:
In reply to:
ff 2 with new rope and and test dummy

I can't think of a situation in which a rope is relevant here... do you mean new sling?

Itīs highly relevant, since, as I said, it is a realistic factor two fall on a dynamic rope, NOT a static fall as in the DMM video. The rope is connected to the dummy, and runs through the bottom carabiner seen in the doodles I attached.

I do not agree that this is all well known stuff. There has been speculation and opinion, but I have yet to see anything but a half-hearted warning from the manufacturers. Most people I know, including quite a few highly skilled instructors and rope access people, use the dyneema just like theyīd use the nylon sling.


Partner cracklover


Dec 19, 2012, 1:09 PM
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Re: [jliungman] Video: Testing FF2 with dyneema [In reply to]
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jliungman wrote:
iknowfear wrote:

this can be summed up:
Don't fall on static stuff.

regarding this:
In reply to:
ff 2 with new rope and and test dummy

I can't think of a situation in which a rope is relevant here... do you mean new sling?

Itīs highly relevant, since, as I said, it is a realistic factor two fall on a dynamic rope, NOT a static fall as in the DMM video. The rope is connected to the dummy, and runs through the bottom carabiner seen in the doodles I attached.

I do not agree that this is all well known stuff. There has been speculation and opinion, but I have yet to see anything but a half-hearted warning from the manufacturers. Most people I know, including quite a few highly skilled instructors and rope access people, use the dyneema just like theyīd use the nylon sling.

Yes, that's right. Most folks have been saying something along the lines of "So long as the rope is in the system, that should limit the force and the dyneema will be fine". Now we know that, at least in some cases, that is not so.

Now a question for you - in the video you linked, it appears that there are two tests, and the sling fails in the first, but not in the second. I gather that the talking (in Swedish) after the second test, while pointing at points on the sling, is saying something like "here, here, and here, the sling is damaged." Is that what happened?

GO


sittingduck


Dec 19, 2012, 1:58 PM
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Re: [cracklover] Video: Testing FF2 with dyneema [In reply to]
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cracklover wrote:
I gather that the talking (in Swedish) after the second test, while pointing at points on the sling, is saying something like "here, here, and here, the sling is damaged." Is that what happened?

GO

The sling was shortened by an overhand knot and both carabiners where clipped in the same loop.
He said that the overhand knot slid until it stopped at the sewing of the sling.

He could see no damage but said that the air was full of fibers floating around.

That is a super makeshift screamer :)


Partner cracklover


Dec 19, 2012, 2:13 PM
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Re: [sittingduck] Video: Testing FF2 with dyneema [In reply to]
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Hmmm... so maybe the OP could explain what he (she?) means about both methods failing?

GO


redlude97


Dec 19, 2012, 2:16 PM
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Re: [cracklover] Video: Testing FF2 with dyneema [In reply to]
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It seems like in the first test and your diagram, the slack in the leg without a knot causes the force to be put on only 1 strand of the sling with the knot in it, is that correct?


(This post was edited by redlude97 on Dec 19, 2012, 2:17 PM)


sittingduck


Dec 19, 2012, 3:21 PM
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Re: [cracklover] Video: Testing FF2 with dyneema [In reply to]
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cracklover wrote:
Hmmm... so maybe the OP could explain what he (she?) means about both methods failing?

GO

At the end of the video the text says that drop nr. 2 also was performed with a nylon sling and then the overhand knot only walked 5 cm (2 inches). Maybe the criteria for success was for the overhand not to walk?

To me it looked like a success, will use it on ice :)


bearbreeder


Dec 19, 2012, 3:50 PM
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Re: [jliungman] Video: Testing FF2 with dyneema [In reply to]
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interesting ... but where is the belay device?

for it to be a realistic you need a belay device ...

the other interesting thing is that the guy at the end goes totally hands free on a gri gri with no backups when inspecting the sling ... which is likely more dangerous over time than the very rare occurrence of a true FF2 fall on dyneema ...

which i think goes to show the "fear" people have of dyneema ... vs the everyday hands free use of a gri gri or other such which is much more likely IMO of killing you ...

theres a focus on the things that very likely wont kill you (dyneema is used my many many many climbers in their anchors including guides and professionals, not too many deaths from that) vs other things that very likely will kill you ...


(This post was edited by bearbreeder on Dec 19, 2012, 3:55 PM)


markcarlson


Dec 19, 2012, 5:46 PM
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Re: [redlude97] Video: Testing FF2 with dyneema [In reply to]
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redlude97 wrote:
It seems like in the first test and your diagram, the slack in the leg without a knot causes the force to be put on only 1 strand of the sling with the knot in it, is that correct?

I am surprised nobody pointed this out sooner. Is this something people do often?

I can not think of a time when I could have possibly weighted one side of a sling like that. That is, any time it looked possible (if a piece blew in a belay anchor,) I changed how the anchor was set up.


jt512


Dec 19, 2012, 9:06 PM
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Re: [bearbreeder] Video: Testing FF2 with dyneema [In reply to]
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bearbreeder wrote:
the other interesting thing is that the guy at the end goes totally hands free on a gri gri with no backups when inspecting the sling ... which is likely more dangerous over time than the very rare occurrence of a true FF2 fall on dyneema ...

which i think goes to show the "fear" people have of dyneema ... vs the everyday hands free use of a gri gri or other such which is much more likely IMO of killing you ....

The fact that the guy went hands free on a(n already locked) grigri is irrelevant to the point of the video, which was the demonstration of a previously unknown (or little known) failure mode of a Dyneema sling. Secondly, there is no general "fear" (with or without quotes) of Dyneema slings, since they have mostly replaced nylon slings in practice. Third, if you ignore the results of the tests in this video, then you're an idiot.

Fourth, fuck Dyneema.

Jay


(This post was edited by jt512 on Dec 19, 2012, 9:07 PM)


bearbreeder


Dec 19, 2012, 11:27 PM
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Re: [jt512] Video: Testing FF2 with dyneema [In reply to]
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jt512 wrote:
The fact that the guy went hands free on a(n already locked) grigri is irrelevant to the point of the video, which was the demonstration of a previously unknown (or little known) failure mode of a Dyneema sling. Secondly, there is no general "fear" (with or without quotes) of Dyneema slings, since they have mostly replaced nylon slings in practice. Third, if you ignore the results of the tests in this video, then you're an idiot.

Fourth, fuck Dyneema.

Jay

blah blah blah blah Wink

like i said i find it quite odd when people go off about things while going against petzl's recommendation of a hands free device ...

no one is ignoring anything here mistah jay ... but there have been a few questions asked as to the test ...

theres plenty of "fear" going around about PASes, dyneema, ATC guides, etc ... on the intrawebs ... but as evidenced by the video, they dont take the basic safety precaution of tying off a device ...

if theres a test with a proper anchor (as others have pointed out) and a belay device in the system ... and dyneema consistently fails ... thats definately something to consider ...

until then ... ill focus on the stuff that will likely kill you

Tongue


patto


Dec 20, 2012, 12:17 AM
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Re: [bearbreeder] Video: Testing FF2 with dyneema [In reply to]
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bearbreeder wrote:
until then ... ill focus on the stuff that will likely kill you
Which is NOT sitting on a tightly cammed gri-gri!


bearbreeder


Dec 20, 2012, 12:27 AM
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patto wrote:
Which is NOT sitting on a tightly cammed gri-gri!

Tying off the GRIGRI to have your hands free


When you want to have your hands free to perform a manipulation, tie-off the GRIGRI. Make sure to correctly lock the tie-off. You may let go of the braking side of the rope only when the device is tied off.






if you really wanted to be "safe" according to petzl Wink

of course if the new RC stance is that the gri gri is now suddenly a hands free device ... now thats something ...

Tongue


jt512


Dec 20, 2012, 12:38 AM
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Re: [bearbreeder] Video: Testing FF2 with dyneema [In reply to]
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bearbreeder wrote:

theres plenty of "fear" going around about PASes, dyneema, ATC guides, etc ... on the intrawebs ... but as evidenced by the video, they dont take the basic safety precaution of tying off a device ...

What you think is "fear" is actually people making intelligent inquiries. And those inquiries are independent of whether they hang off a fully cammed grigri or not without a backup.

In reply to:
if theres a test with a proper anchor (as others have pointed out) and a belay device in the system ... and dyneema consistently fails ... thats definately something to consider ...

What's that called, the incautionary principle: "If anything can go right, it will"?

In reply to:
until then ... ill focus on the stuff that will likely kill you

Assuming everything in climbing is safe until absolutely proved otherwise is pretty stupid, although it is true that you will probably be ok.

Jay


bearbreeder


Dec 20, 2012, 12:52 AM
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Re: [jt512] Video: Testing FF2 with dyneema [In reply to]
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jt512 wrote:

What you think is "fear" is actually people making intelligent inquiries. And those inquiries are independent of whether they hang off a fully cammed grigri or not without a backup.


What's that called, the incautionary principle: "If anything can go right, it will"?


Assuming everything in climbing is safe until absolutely proved otherwise is pretty stupid, although it is true that you will probably be ok.

Jay

no its simply focusing on things that are most likely to go wrong and kill you ... dont assume EVERYTHING is safe ... ANYTHING can kill you, but you cant worry about everything can ya now

the fear about "the deadly dyneema" occupies many intraweb threads ...

how about more basic stuff like wearing a helmet, which of course you ALWAYS do when leading dontcha mistah JAY Wink

what we have is an incomplete test IMO ... people have pointed out the funny anchor setup ... and we DO belay with a device or other such dont we ...

how many dyneema anchor FF2 failures have we had in real life ... i suspect there many be at least one or two since its a very common material ... and in fact i expect that there are at least a few nylon or cordellette failures in history as well ... but compare that to the much more common ways to die ... worry about the things that matter

tying off a proper anchor with dyneema, nylon, cord isnt whats going to kill you tmr (well it might if you are on such sketchy anchors that you cant clip the belay bolt or a piece, but are YOU doing such a climb mistah jay Tongue)

i once remember someone who yakked all about only climbing with partners who knew how to built zpulleys, using only lockers at anchors, unsafe PAS/dyneema ... what did he do? ... rapped off the ends of his rope ...


bottom line ... i want to see more info, a proper anchor setup and a belay device in the system ...

and if you are worried about being "safe" ... dont use a device that aint hands free according to the manufacturer ... well hands free Wink


(This post was edited by bearbreeder on Dec 20, 2012, 1:00 AM)


jt512


Dec 20, 2012, 1:05 AM
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Re: [bearbreeder] Video: Testing FF2 with dyneema [In reply to]
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bearbreeder wrote:
jt512 wrote:

What you think is "fear" is actually people making intelligent inquiries. And those inquiries are independent of whether they hang off a fully cammed grigri or not without a backup.


What's that called, the incautionary principle: "If anything can go right, it will"?


Assuming everything in climbing is safe until absolutely proved otherwise is pretty stupid, although it is true that you will probably be ok.

Jay

no its simply focusing on things that are most likely to go wrong and kill you ... dont assume EVERYTHING is safe ... ANYTHING can kill you, but you cant worry about everything can ya now

the fear about "the deadly dyneema" occupies many intraweb threads ...

how about more basic stuff like wearing a helmet, which of course you ALWAYS do when leading dontcha mistah JAY Wink

what we have is an incomplete test IMO ... people have pointed out the funny anchor setup ... and we DO belay with a device or other such dont we ...

how many dyneema anchor FF2 failures have we had in real life ... i suspect there many be at least one or two since its a very common material ... and in fact i expect that there are at least a few nylon or cordellette failures in history as well ... but compare that to the much more common ways to die ... worry about the things that matter

tying off a proper anchor with dyneema, nylon, cord isnt whats going to kill you tmr (well it might if you are on such sketchy anchors that you cant clip the belay bolt or a piece, but are YOU doing such a climb mistah jay Tongue)

i once remember someone who yakked all about only climbing with partners who knew how to built zpulleys, using only lockers at anchors, unsafe PAS/dyneema ... what did he do? ... rapped off the ends of his rope ...


bottom line ... i want to see more info, a proper anchor setup and a belay device in the system ...

and if you are worried about being "safe" ... dont use a device that aint hands free according to the manufacturer ... well hands free Wink

Do you ever write any sentences that aren't logical fallacies?

Jay


bearbreeder


Dec 20, 2012, 1:10 AM
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jt512 wrote:

Do you ever write any sentences that aren't logical fallacies?

Jay

yadda yadda yaddaa ... did ya say something mistah jay ;)

i suggest writing to all those manufacturers who make dyneema and tell them how "unsafe" you consider it to be for anchor usage ... as a recognized expert and knowing fully well that they did not test their materials in common usage setups ... theyll be shocked that you didnt come forward to them sooner ... this will insure positive change

or are you more interested in telling people they are "idiots" Wink


(This post was edited by bearbreeder on Dec 20, 2012, 1:11 AM)


healyje


Dec 20, 2012, 1:25 AM
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Re: [jliungman] Video: Testing FF2 with dyneema [In reply to]
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It's not new and it's not particularly alarming - people have been warned for some time that knotting dyneema is a bad idea. More of an issue with skinny dyneema slings is keeping and using them to long. They are designed as a ultralite, short-lifespan, alpine consumable and were never intended for long term use on trad racks or sport draws.


Syd


Dec 20, 2012, 2:26 AM
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healyje wrote:
More of an issue with skinny dyneema slings is keeping and using them to long. They are designed as a ultralite, short-lifespan, alpine consumable and were never intended for long term use on trad racks or sport draws.

It's not just dyneema that's short lived. I was surprised reading this recently:
" Testing by Todd Vogel at Blue Water Ropes showed consistent strength losses for most cords and tapes, after one or two years use the strength dropped to 60% even when there was no obvious wear. I’d be replacing critical slings such as cordellettes every year or two."

Also:
http://www.efclimbers.net/resources/Knot-and-cord-strength.pdf


jt512


Dec 20, 2012, 3:11 AM
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bearbreeder wrote:
jt512 wrote:

Do you ever write any sentences that aren't logical fallacies?

Jay

yadda yadda yaddaa ... did ya say something mistah jay ;)

i suggest writing to all those manufacturers who make dyneema and tell them how "unsafe" you consider it to be for anchor usage ... as a recognized expert and knowing fully well that they did not test their materials in common usage setups ... theyll be shocked that you didnt come forward to them sooner ... this will insure positive change

or are you more interested in telling people they are "idiots" Wink

I don't know how you escaped my killfile on this laptop, but back you go.

*plonk*


patto


Dec 20, 2012, 3:48 AM
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bearbreeder wrote:
patto wrote:
Which is NOT sitting on a tightly cammed gri-gri!
if you really wanted to be "safe" according to petzl Wink
This does not help your argument at all.

bearbreeder wrote:
of course if the new RC stance is that the gri gri is now suddenly a hands free device ... now thats something ...
You are confusing belaying hands free with having a loaded locked off gri-gri hands free. They are NOT the same!


A loaded grigri is 100% safe to go hands free provided the cam isn't forced open.


Forcing a cam open takes a fair bit of force that is very unlikely to occur when loaded. Like many such situations if you want to make it super safe tying off helps.


bearbreeder


Dec 20, 2012, 4:05 AM
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Re: [patto] Video: Testing FF2 with dyneema [In reply to]
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patto wrote:
bearbreeder wrote:
patto wrote:
Which is NOT sitting on a tightly cammed gri-gri!
if you really wanted to be "safe" according to petzl Wink
This does not help your argument at all.

bearbreeder wrote:
of course if the new RC stance is that the gri gri is now suddenly a hands free device ... now thats something ...
You are confusing belaying hands free with having a loaded locked off gri-gri hands free. They are NOT the same!


A loaded grigri is 100% safe to go hands free provided the cam isn't forced open.


Forcing a cam open takes a fair bit of force that is very unlikely to occur when loaded. Like many such situations if you want to make it super safe tying off helps.

ummmm ... that petzl diagram was very specific for descending (rappelling) on a gri gri ...

so you are saying that its 100% safe for one to go "hands free" on a gri gri if the cam is engaged ...

so for example is my climber is resting on the rope, the cam is fully engaged, i can let go of the brake hand ?????????

of course if you are swinging around theres absolutely no chance anything will happen at all will there now Wink

im gonna go ask petzl about it ... i suspect theyll know if its "100% safe"

Tongue


(This post was edited by bearbreeder on Dec 20, 2012, 4:10 AM)


Partner rgold


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Re: [jliungman] Video: Testing FF2 with dyneema [In reply to]
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jliungman wrote:
Hi!

The results, in short, show that under heavy but entirely realistic loads (ff 2 with new rope and and test dummy), a new dyneema sling fails completely. This happens when the dyneema is shortened using two techniques which, at least in Scandinavia, are common and taught by instructors.
Any thoughts?

The loads are heavy, that's for sure. "Entirely realistic" is questionable, and "complete failure" appears to be just plain wrong. What failed was a single strand of clove-hitched dyneema. We can probably all agree that it is a bad idea to take a statically belayed factor-2 fall on a single strand of clove-hitched dyneema.

On the other side of the coin, most people and all engineers believe that one's gear should have safety margins, which is to say that is should be capable of withstanding loads in excess, typically significantly in excess, of what might be expected in the field.

Industrial-level safety margins are not possible for climbing gear in general; they would make the gear too heavy to be practical. So climbers (or those climbers who actually think about such things) are used to operating far closer to the safety edge when climbing then they would be in their ordinary lives.

The dyneema tests continue to suggest that there is almost no safety margin, in the engineering sense, with knotted dyneema slings, meaning that knotted sling failure loads, for brand-new material, are at the edge of what could conceivably occur in certain unusual climbing situations, and this is without any allowance for the relatively rapid decline in strength, compared to nylon, of dyneema.

I doubt there will be many people who will chuck their trad draws because of this, nor should there be. As I said, for practical reasons, climbers have to accept low safety margins in their gear. Most trad gear will cannot hold the largest loads that one can expect in the field, for example.

This does not mean, internet static notwithstanding, that climbers should strive to remain as ignorant as possible about the performance of their gear under challenging conditions, or that knowledge of limitations has to be equated with fear of usage, but the internet is what it is.

Practically speaking, I'd be cautious about knotting dyneema in very high-load applications like belay anchors, especially if, say, you are rope-soloing and so employing totally static belays. Most of the time, it still seems highly unlikely to matter. However, it is also true that there are effective practices, such as tying in with the rope, with orders of magnitude higher margins of safety.


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Dec 20, 2012, 9:24 AM
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Re: [jliungman] Video: Testing FF2 with dyneema [In reply to]
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Thanks for sharing this!

jliungman wrote:
The results, in short, show that under heavy but entirely realistic loads (ff 2 with new rope and and test dummy), a new dyneema sling fails completely. This happens when the dyneema is shortened using two techniques which, at least in Scandinavia, are common and taught by instructors.
Any thoughts? To me the results imply that we should avoid knotting dyneema altogether, and use this fantastic material only in full length, stitched slings (like quick draws). At least until we know more about which nylon/dyneema/widths/knots combinations work and which donīt.

My conclusions are different from yours.

I would say that we should absolutely avoid any situation in which a serious load could conceivably come onto a single strand of knotted dyneema. The first test shows one such situation. However I've never done that, and would not be likely to. So that raises the question of whether this failure mode has any bearing on my climbing?

To answer that, I will generalize the failure mode to see all the cases in which it could apply. After doing that, I conclude that to be safe, a dyneema sling should never have more than one knot/hitch put in it. Not unless it is only one part of a more complex rigging.

GO


healyje


Dec 20, 2012, 10:43 AM
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Re: [Syd] Video: Testing FF2 with dyneema [In reply to]
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Syd wrote:
healyje wrote:
More of an issue with skinny dyneema slings is keeping and using them to long. They are designed as a ultralite, short-lifespan, alpine consumable and were never intended for long term use on trad racks or sport draws.

It's not just dyneema that's short lived. I was surprised reading this recently:
" Testing by Todd Vogel at Blue Water Ropes showed consistent strength losses for most cords and tapes, after one or two years use the strength dropped to 60% even when there was no obvious wear. I’d be replacing critical slings such as cordellettes every year or two."

Also: http://www.efclimbers.net/resources/Knot-and-cord-strength.pdf

The testing here is pretty scattershot with regard to the knowing the ages of the materials under test - some they do, some they don't. The conclusion you draw is far too sweeping. It does a better job on knots than on material aging and I'd personally look elsewhere for that testing. A two year replacement cycle is not necessary on much beyond skinny dyneema - certainly not 1" nylon or 11mm dyneema/nylon. Cords are a somewhat different matter and I don't use them.


patto


Dec 20, 2012, 11:05 AM
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Re: [bearbreeder] Video: Testing FF2 with dyneema [In reply to]
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bearbreeder wrote:
ummmm ... that petzl diagram was very specific for descending (rappelling) on a gri gri ...
I've never said otherwise.

bearbreeder wrote:
so you are saying that its 100% safe for one to go "hands free" on a gri gri if the cam is engaged ...
I have made myself quite clear.

bearbreeder wrote:
so for example is my climber is resting on the rope, the cam is fully engaged, i can let go of the brake hand ?????????
Yes. You can safely do so.

bearbreeder wrote:
of course if you are swinging around theres absolutely no chance anything will happen at all will there now Wink
No there isn't any chance provided the cam isn't forced open. Simply swinging around wont do this.

I am not advocating rapping or belaying like this. That is a decision only you can make yourself. But personally I am happy to rely on the grigri hands free for MY personal safety when the cam is engaged.

In fact I did so a hundred or so times three days ago as I used a gri-gri method to jug up a 50m line. Angelic Know and understand your gear. This goes beyond simply reading the instruction manual!

Likewise, my partner spent about 40 minutes typing emails on his android tablet while belaying me the other day. He had me on a gri-gri and had a grip on the brake rope so I was not concerned.

(Aid climbing is not the fastest of sports Wink)


(This post was edited by patto on Dec 20, 2012, 11:09 AM)


JimTitt


Dec 20, 2012, 11:15 AM
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Re: [cracklover] Video: Testing FF2 with dyneema [In reply to]
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cracklover wrote:
Thanks for sharing this!

jliungman wrote:
The results, in short, show that under heavy but entirely realistic loads (ff 2 with new rope and and test dummy), a new dyneema sling fails completely. This happens when the dyneema is shortened using two techniques which, at least in Scandinavia, are common and taught by instructors.
Any thoughts? To me the results imply that we should avoid knotting dyneema altogether, and use this fantastic material only in full length, stitched slings (like quick draws). At least until we know more about which nylon/dyneema/widths/knots combinations work and which donīt.

My conclusions are different from yours.

I would say that we should absolutely avoid any situation in which a serious load could conceivably come onto a single strand of knotted dyneema. The first test shows one such situation. However I've never done that, and would not be likely to. So that raises the question of whether this failure mode has any bearing on my climbing?

To answer that, I will generalize the failure mode to see all the cases in which it could apply. After doing that, I conclude that to be safe, a dyneema sling should never have more than one knot/hitch put in it. Not unless it is only one part of a more complex rigging.

GO

The University of Stuttgart did drop tests on most of the common materials clove hitched into a karabiner as part of DAV research for various cordalette/equalette systems where a single hitched strand may well ultimately be called on to take the entire load. Dyneema wasnīt the winner!


bearbreeder


Dec 20, 2012, 12:49 PM
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Re: [patto] Video: Testing FF2 with dyneema [In reply to]
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patto wrote:
bearbreeder wrote:
ummmm ... that petzl diagram was very specific for descending (rappelling) on a gri gri ...
I've never said otherwise.

bearbreeder wrote:
so you are saying that its 100% safe for one to go "hands free" on a gri gri if the cam is engaged ...
I have made myself quite clear.

bearbreeder wrote:
so for example is my climber is resting on the rope, the cam is fully engaged, i can let go of the brake hand ?????????
Yes. You can safely do so.

bearbreeder wrote:
of course if you are swinging around theres absolutely no chance anything will happen at all will there now Wink
No there isn't any chance provided the cam isn't forced open. Simply swinging around wont do this.

I am not advocating rapping or belaying like this. That is a decision only you can make yourself. But personally I am happy to rely on the grigri hands free for MY personal safety when the cam is engaged.

In fact I did so a hundred or so times three days ago as I used a gri-gri method to jug up a 50m line. Angelic Know and understand your gear. This goes beyond simply reading the instruction manual!

Likewise, my partner spent about 40 minutes typing emails on his android tablet while belaying me the other day. He had me on a gri-gri and had a grip on the brake rope so I was not concerned.

(Aid climbing is not the fastest of sports Wink)

asked

Hi Petzl,

Ive been told that

"A loaded grigri is 100% safe to go hands free provided the cam isn't forced open."

Is this true? Can i take my brake hand off the rope when rappelling or belaying without any backup knots if the cam is fully engaged?

Thanks,


answered

Hello, sorry to say that what you have been told is absolutely wrong. In all our technical instruction we clearly say never let your brake hand go off the rope. Please consult :

http://www.petzl.com/files/all/technical-notice/Sport/D14-GRIGRI2.pdf


we are RCers, we know better than the manufacturer when something is "100% safe" ... take those brake hands off those gri gris now ya gumbays, cause we at RC say so !!!

Tongue


(This post was edited by bearbreeder on Dec 20, 2012, 12:50 PM)


patto


Dec 20, 2012, 1:35 PM
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Re: [bearbreeder] Video: Testing FF2 with dyneema [In reply to]
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Laugh Oh dear.... You are a very odd character.

I wouldn't have expected any other response from Petzl.


That doesn't change the facts though! Wink


Also this is something I have not encouraged or advocated: Can i take my brake hand off the rope when rappelling or belaying without any backup knots if the cam is fully engaged?


(This post was edited by patto on Dec 20, 2012, 1:41 PM)


jliungman


Dec 20, 2012, 2:58 PM
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Re: [patto] Video: Testing FF2 with dyneema [In reply to]
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Sorry, been busy elsewhere for a day, but will try to clarify a few things that seem to be in question!

1. The person talking in the video has a stopper knot further down the rope under the grigri. It shows in sequences I have edited out. So let us focus on the relevant bits.

2. All the material (sling, rope) is new.

3. The end of the rope that is normally held by the belay device is here tied directly to the anchor. I assume that this is just a way of making the tests comparable, since having a human belayer would add randomness to the tests. In a proper standard test scenario, the rope would have been wound a couple of times around a bar to add some simulated dynamism, but would not have inlcuded a belay device. Correct me if I am wrong. Also, this test uses a dummy doll to simulate the slightly dynamic properties of a body rather than the rigid test weight used in a standard test, so it will balance out at least partially.

4. True, in the second scenario, with the double overhand, there is not complete failure. Bad wording from me in the OP. The stitching seems to be stopping the knot sliding. I would have to go back to the raw material to see if there were examples where the stitching was differently positioned. The sliding it itself would, of course, completely alter the direction and loading of a two point anchor.

5. The technique of equalizing an anchor by tying a clove hitch around a carabiner and loading only one strand of a sling is still common here in Sweden. If it is not so in other parts of the world then all is well there and we need to look at this only locally. I for one will avoid it, but itīs not something I thought of before this video.

Then, adding some of my opinion here rather than fact... The argument that other things kill climbers, or that the scenario is somehow extreme, is faulty. If you donīt plan on having ff2 falls, and always having two perfectly weighted pieces - or if you plan on getting hit in the head by a rock rather than take a whipper - then why not climb with much weaker (and lighter, and cheaper) setups? The point, as has been mentioned here, is that we want great margins of safety in our systems. And I think these clips hint that this margin of safety is reduced with Dyneema in some setups. Sure, if we add a belay device and two pieces of pro we have smaller loads. But to me the video still indicates something is wrong, since this is still a dynamic fall (as opposed to DMMs videos of competely static testing). It needs more testing, and I have asked some manufacturers about this. They have promised to look into it, but I guess they have a lot on their lists of things to check in the lab.


healyje


Dec 20, 2012, 3:45 PM
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Re: [jliungman] Video: Testing FF2 with dyneema [In reply to]
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jliungman wrote:
But to me the video still indicates something is wrong

I'm inclined to disagree. Skinny dyneema slings were developed in a deliberate alpine trade-off for weight and are not a durable good, neither do they bear knotting of any kind.


bearbreeder


Dec 20, 2012, 3:48 PM
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Re: [jliungman] Video: Testing FF2 with dyneema [In reply to]
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jliungman wrote:
The point, as has been mentioned here, is that we want great margins of safety in our systems.


well first of all, tie off a gri gri when going hands free as per the manufacturers recommendations ... that will be most beneficial to your "margin of safety" in the video ... i presume you dont go hands free with a gri gri with your clients as guides and instructor ...

second of all its all about choices ... for example there are REAL incidents with cut ropes, yet no one is suggesting we ONLY use twin ropes ...

third of all ... put a belay device in the system ... you claim that it is a "realistic" test with dummies and dynamic ropes ... but when was the last time you belayed without a device or munter or hip belay in the system???

im not saying the results arent interesting or concerning to some degree ... if you claim to be testing realistic conditions, then do it with as close to a real life scenario as possible ...


patto


Dec 20, 2012, 5:19 PM
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Re: [bearbreeder] Video: Testing FF2 with dyneema [In reply to]
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bearbreeder wrote:
well first of all, tie off a gri gri when going hands free as per the manufacturers recommendations ... that will be most beneficial to your "margin of safety" in the video ...

No matter how many times you repeat it it wont be true bearbreeder.


bearbreeder


Dec 20, 2012, 5:31 PM
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Re: [patto] Video: Testing FF2 with dyneema [In reply to]
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patto wrote:

No matter how many times you repeat it it wont be true bearbreeder.

sorry if i take petzl's word over some RCer who "knows" better that its "100% safe" Tongue


gunkiemike


Dec 20, 2012, 6:42 PM
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Re: [Syd] Video: Testing FF2 with dyneema [In reply to]
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Syd wrote:
It's not just dyneema that's short lived. I was surprised reading this recently:
" Testing by Todd Vogel at Blue Water Ropes showed consistent strength losses for most cords and tapes, after one or two years use the strength dropped to 60% even when there was no obvious wear. I’d be replacing critical slings such as cordellettes every year or two."

Well, that's interesting. I just had 3 old (16-18 yr old) Dyneema slings pull tested. All were lightly used. They broke at:
4600 lb
4800 lb
and stayed intact to 5000 lb.

And two of them were BW brand.


Syd


Dec 20, 2012, 9:27 PM
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Re: [healyje] Video: Testing FF2 with dyneema [In reply to]
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healyje wrote:
A two year replacement cycle is not necessary on much beyond skinny dyneema - certainly not 1" nylon or 11mm dyneema/nylon.

I use 18mm nylon. Mine were all well used, 5 to 7 years old and looking rather furry, so I replaced them all after reading the article.

Accidents are usually a combination of factors, and I'd rather remove any possible factors for a measly few dollars than put my life at risk. Todd Skinner is a classic example of someone who pushed his gear rather than spend a dollar.


Syd


Dec 20, 2012, 9:33 PM
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Re: [bearbreeder] Video: Testing FF2 with dyneema [In reply to]
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bearbreeder wrote:

sorry if i take petzl's word over some RCer who "knows" better that its "100% safe" Tongue

I'm with you bearbreeder. Hands off might be fine 10,000 times in succession but it only takes one time for it not to be OK. As I said, it's usually a combination of things that cause accidents - perhaps a new slick rope, slightly skinnier, slightly wet etc etc ... and the result can easily be lethal.


jliungman


Dec 21, 2012, 11:50 AM
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Re: [Syd] Video: Testing FF2 with dyneema [In reply to]
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As for whether or not a single strand should be loaded I have added a sketch of a typical (for where Iīm from) anchor setup. A clove hitch on each carabiner and slack between the two. One strand from each carabiner runs to the master point (fig 8). It can be used to get some extra length out of your single sling compared to pulling four strands down to the master point.

This is not the exact same setup as the video, but the doubled version. Still, only a single strand from each point. If the clove hitches were to slip, you would at the least get a change in load direction on the anchors. I say this just to explain why the first setup was tested.

Iīm by no means campaigning against dyneema and I am a bit surprised at the emotional reactions. I do think it is relevant to show that there are a number of situations where dyneema cannot be used like nylon. And it IS being used like nylon (although many here on the forum seem to be well aware of the problems).

One recent example is a friend who was out ice-clogging, using a baudrier parisienne to keep his clogging device in a good position (a 120 cm sling around the shoulders). When the dyneema was wet and he weighted the knot, it slipped and compressed his torso, and would have killed him had he not had the presence of mind to transfer weight to his backup rope in time. There are specific details involved, but again, an experienced climber used dyneema like he would use nylon - and it did not work.

Dyneema has one significant advantage - low weight. But my impression is that when improperly used this advantage vanishes - nylon is stronger per weight unit as soon as you start factoring in dynamics and knots. This means that unless you want to bring both types on a climb - which would negate the weight reduction you wanted when you bought dyneema in the first place - then you might as well stick to a couple of nylon slings. Theyīll get you through most situation and you donīt need to worry about all the scenarios where it might slip or break. 100% of my slings are still dyneema, but Iīm beginning to wonder why? Maybe because thatīs all they had in the store?
Attachments: anchor.png (11.9 KB)


Partner rgold


Dec 21, 2012, 1:04 PM
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Re: [jliungman] Video: Testing FF2 with dyneema [In reply to]
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The two-anchor clove-hitched set-up you pictured in common throughout Europe, less so in the U.S, where much longer slings (cordelettes) are carried and everything is anchored with a single knot at the so-called "power point."

Personally, I typically use both nylon and dyneema slings. My trad draws are all made up with thin dyneema, but I also carry a few over-the-shoulder slings that are nylon. I don't knot the dyneema, and in any case I rarely use anything but the climbing rope itself for anchoring, but that's just me.

By the way, there are a number of hybrid dyneema/nylon slings available. I don't know if he's paying any attention to this thread, but I think Mal Daly has done essentially the same test as the one here with such materials and found the clove-hitched sling to be stronger than some of the carabiners they were using.


redlude97


Dec 21, 2012, 3:28 PM
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Re: [rgold] Video: Testing FF2 with dyneema [In reply to]
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rgold wrote:
The two-anchor clove-hitched set-up you pictured in common throughout Europe, less so in the U.S, where much longer slings (cordelettes) are carried and everything is anchored with a single knot at the so-called "power point."

Personally, I typically use both nylon and dyneema slings. My trad draws are all made up with thin dyneema, but I also carry a few over-the-shoulder slings that are nylon. I don't knot the dyneema, and in any case I rarely use anything but the climbing rope itself for anchoring, but that's just me.

By the way, there are a number of hybrid dyneema/nylon slings available. I don't know if he's paying any attention to this thread, but I think Mal Daly has done essentially the same test as the one here with such materials and found the clove-hitched sling to be stronger than some of the carabiners they were using.
Not clear exactly what you are saying, but all "dyneema" slings are hybrids of dyneema and nylon. Its easy to tell because dyneema doesn't hold color.


acorneau


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redlude97 wrote:
Not clear exactly what you are saying, but all "dyneema" slings are hybrids of dyneema and nylon. Its easy to tell because dyneema doesn't hold color.

Some slings, like the BW Titan sling material, is much more evenly split between nylon and Dyneema whereas the skinny slings like BD's are majority Dyneema with just a little nylon.

This...


... versus this...



USnavy


Dec 22, 2012, 1:03 AM
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Re: [bearbreeder] Video: Testing FF2 with dyneema [In reply to]
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bearbreeder wrote:
patto wrote:
bearbreeder wrote:
ummmm ... that petzl diagram was very specific for descending (rappelling) on a gri gri ...
I've never said otherwise.

bearbreeder wrote:
so you are saying that its 100% safe for one to go "hands free" on a gri gri if the cam is engaged ...
I have made myself quite clear.

bearbreeder wrote:
so for example is my climber is resting on the rope, the cam is fully engaged, i can let go of the brake hand ?????????
Yes. You can safely do so.

bearbreeder wrote:
of course if you are swinging around theres absolutely no chance anything will happen at all will there now Wink
No there isn't any chance provided the cam isn't forced open. Simply swinging around wont do this.

I am not advocating rapping or belaying like this. That is a decision only you can make yourself. But personally I am happy to rely on the grigri hands free for MY personal safety when the cam is engaged.

In fact I did so a hundred or so times three days ago as I used a gri-gri method to jug up a 50m line. Angelic Know and understand your gear. This goes beyond simply reading the instruction manual!

Likewise, my partner spent about 40 minutes typing emails on his android tablet while belaying me the other day. He had me on a gri-gri and had a grip on the brake rope so I was not concerned.

(Aid climbing is not the fastest of sports Wink)

asked

Hi Petzl,

Ive been told that

"A loaded grigri is 100% safe to go hands free provided the cam isn't forced open."

Is this true? Can i take my brake hand off the rope when rappelling or belaying without any backup knots if the cam is fully engaged?

Thanks,


answered

Hello, sorry to say that what you have been told is absolutely wrong. In all our technical instruction we clearly say never let your brake hand go off the rope. Please consult :

http://www.petzl.com/files/all/technical-notice/Sport/D14-GRIGRI2.pdf


we are RCers, we know better than the manufacturer when something is "100% safe" ... take those brake hands off those gri gris now ya gumbays, cause we at RC say so !!!

Tongue
First of all, the guy you emailed was not "Petzl," but rather likely some sales rep who could very well know less about climbing than many of the senior members of this forum. If the guy is actually a solid climber, he knows that statement was bullshit but he had to say it for liability reasons. Second, the GriGri is one of the most commonly used devices in slacklining. We use it to serve as a mechanical brake to stop the pulley system from despooling. When using the GriGri as a brake in long slacklines, the force subjected to the GriGri is far greater than what is normally seen in the climbing world, and the device is always operated "hands free" with nothing holding the rope. To date I have never heard of a GriGri randomly slipping without being overloaded. My GriGri has likely had over 100 hours of "hands free" time on it holding my slackline. I normally tension my longline in excess of 2,000 lbf which means the GriGri has to hold in excess of 400 lbf. at times.


(This post was edited by USnavy on Dec 22, 2012, 1:07 AM)


USnavy


Dec 22, 2012, 1:12 AM
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Re: [redlude97] Video: Testing FF2 with dyneema [In reply to]
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redlude97 wrote:
rgold wrote:
The two-anchor clove-hitched set-up you pictured in common throughout Europe, less so in the U.S, where much longer slings (cordelettes) are carried and everything is anchored with a single knot at the so-called "power point."

Personally, I typically use both nylon and dyneema slings. My trad draws are all made up with thin dyneema, but I also carry a few over-the-shoulder slings that are nylon. I don't knot the dyneema, and in any case I rarely use anything but the climbing rope itself for anchoring, but that's just me.

By the way, there are a number of hybrid dyneema/nylon slings available. I don't know if he's paying any attention to this thread, but I think Mal Daly has done essentially the same test as the one here with such materials and found the clove-hitched sling to be stronger than some of the carabiners they were using.
Not clear exactly what you are saying, but all "dyneema" slings are hybrids of dyneema and nylon. Its easy to tell because dyneema doesn't hold color.
That is not true. The new Petzl Ange dogbone is 100% Dyneema. Only the stitching is nylon. But yes, most Dyneema slings are hybrids.


(This post was edited by USnavy on Dec 22, 2012, 1:13 AM)


jliungman


Dec 22, 2012, 4:04 AM
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Re: [rgold] Video: Testing FF2 with dyneema [In reply to]
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rgold wrote:
The two-anchor clove-hitched set-up you pictured in common throughout Europe, less so in the U.S, where much longer slings (cordelettes) are carried and everything is anchored with a single knot at the so-called "power point."

Personally, I typically use both nylon and dyneema slings. My trad draws are all made up with thin dyneema, but I also carry a few over-the-shoulder slings that are nylon. I don't knot the dyneema, and in any case I rarely use anything but the climbing rope itself for anchoring, but that's just me.

By the way, there are a number of hybrid dyneema/nylon slings available. I don't know if he's paying any attention to this thread, but I think Mal Daly has done essentially the same test as the one here with such materials and found the clove-hitched sling to be stronger than some of the carabiners they were using.

You have some good points, rgold. The proportion of nylon vs dyneema would be an obvious starting point for some serious tests. The sling in the video was a Mammut, as far as I know. What model, I donīt know.

Also, I agree that a mix of slings may be the preferable approach to a multi-pitch climber, specifically carrying a 120-240 nylon sling for the multi-point anchor. In most situations itīs unnecessary to knot the sling in the manners shown in the video (and personally I never liked it anyway). But I find that reality does not always permit the school-book anchor setups, and we end up having to shorten some sling or strand, especially on poor pro - when we might add an extra point as an afterthought. I mostly donīt like involving my rope in the anchor unless the pro is within reach (in case I need to retreat quickly).

Anyway, thanks for the input. Iīll get back if I get the guys behind the testing to finally summarize their results into something more solid, or if one of the manufacturers decide to put their minds to it.

Cheers!

John


jliungman


Dec 22, 2012, 4:06 AM
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Re: [cracklover] Video: Testing FF2 with dyneema [In reply to]
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cracklover wrote:
My conclusions are different from yours.

I would say that we should absolutely avoid any situation in which a serious load could conceivably come onto a single strand of knotted dyneema. The first test shows one such situation. However I've never done that, and would not be likely to. So that raises the question of whether this failure mode has any bearing on my climbing?

To answer that, I will generalize the failure mode to see all the cases in which it could apply. After doing that, I conclude that to be safe, a dyneema sling should never have more than one knot/hitch put in it. Not unless it is only one part of a more complex rigging.

GO

Good points. I think we draw similar conclusions!

John


bearbreeder


Dec 22, 2012, 4:16 AM
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Re: [USnavy] Video: Testing FF2 with dyneema [In reply to]
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USnavy wrote:
First of all, the guy you emailed was not "Petzl," but rather likely some sales rep who could very well know less about climbing than many of the senior members of this forum. If the guy is actually a solid climber, he knows that statement was bullshit but he had to say it for liability reasons. Second, the GriGri is one of the most commonly used devices in slacklining. We use it to serve as a mechanical brake to stop the pulley system from despooling. When using the GriGri as a brake in long slacklines, the force subjected to the GriGri is far greater than what is normally seen in the climbing world, and the device is always operated "hands free" with nothing holding the rope. To date I have never heard of a GriGri randomly slipping without being overloaded. My GriGri has likely had over 100 hours of "hands free" time on it holding my slackline. I normally tension my longline in excess of 2,000 lbf which means the GriGri has to hold in excess of 400 lbf. at times.

well first of all you do know when swinging around, leaning over with a measuring tape, wearing loose clothes ... things can catch and get bumped ... now you may say this is very unlikely, but then again no more so than a true factor 2 fall on a dyneema sling with a funny knot and no belay device ...

second of all ill still take PETZLs word over yours ... since you believe its perfectly fine to take the hand right off the brake when rapping or belaying by implication once its loaded Wink

that should be the "official" RC line ... just take your hands off babiii Tongue

it takes 10 seconds to tie a quick slip knot ...


(This post was edited by bearbreeder on Dec 22, 2012, 4:17 AM)


patto


Dec 22, 2012, 4:24 AM
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Re: [bearbreeder] Video: Testing FF2 with dyneema [In reply to]
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Despite all the words you haven't yet even explained how the statement is incorrect. A loaded grigri is 100% safe to go hands free provided the cam isn't forced open.

Know and understand you equipment. It seems that you don't. I suppose you wouldn't trust a Reverso in autoblock in hands free either. Crazy


bearbreeder


Dec 22, 2012, 4:45 AM
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Re: [patto] Video: Testing FF2 with dyneema [In reply to]
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patto wrote:
Despite all the words you haven't yet even explained how the statement is incorrect. A loaded grigri is 100% safe to go hands free provided the cam isn't forced open.

Know and understand you equipment. It seems that you don't. I suppose you wouldn't trust a Reverso in autoblock in hands free either. Crazy


oh GOD mista PATTO ... i just explained it to you ... when yr swinging over the place with a measuring tape, leaning over, etc ... there is the possibility that something will catch or bump

you obviously dont care what PETZL says as regard to it ... do you take your brake hand off the gri gri when belaying too to fiddle around all day when yr partner is hanging ... if so please dont climb with me Wink

youre obviously too LAZY to take a few seconds to tie a knot with your partners life on the line ... do you even let them know youre going to take your hand off the brake ???? ... or do you make that decision for em without informing em

ill repeat it again

Hello, sorry to say that what you have been told is absolutely wrong. In all our technical instruction we clearly say never let your brake hand go off the rope.

ill take PETZLs word over some RCers ANYDAY on the usage of their belay device

if you like you can tell PETZL how they should use their device Tongue


USnavy


Dec 22, 2012, 4:48 AM
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Re: [bearbreeder] Video: Testing FF2 with dyneema [In reply to]
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bearbreeder wrote:
USnavy wrote:
First of all, the guy you emailed was not "Petzl," but rather likely some sales rep who could very well know less about climbing than many of the senior members of this forum. If the guy is actually a solid climber, he knows that statement was bullshit but he had to say it for liability reasons. Second, the GriGri is one of the most commonly used devices in slacklining. We use it to serve as a mechanical brake to stop the pulley system from despooling. When using the GriGri as a brake in long slacklines, the force subjected to the GriGri is far greater than what is normally seen in the climbing world, and the device is always operated "hands free" with nothing holding the rope. To date I have never heard of a GriGri randomly slipping without being overloaded. My GriGri has likely had over 100 hours of "hands free" time on it holding my slackline. I normally tension my longline in excess of 2,000 lbf which means the GriGri has to hold in excess of 400 lbf. at times.

since you believe its perfectly fine to take the hand right off the brake when rapping or belaying by implication once its loaded Wink
I never said anything like that. I said the GriGri in my slackline is able to hold a load without a hand on the rope. I always keep my hand on the rope when belaying - no exceptions. However, if I am rappelling and doing route work, I will take my hand off the rope, but I still tie a back-up knot most of the time. But I do not tie a back-up knot in the rope because I think the GriGri is some how going to magically decam and drop me. I tie a knot in the rope in case I drop my drill on the GriGri and jam the cam open inadvertently or something of the like.


(This post was edited by USnavy on Dec 22, 2012, 4:53 AM)


patto


Dec 22, 2012, 4:50 AM
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Re: [bearbreeder] Video: Testing FF2 with dyneema [In reply to]
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bearbreeder wrote:
oh GOD mista PATTO ... i just explained it to you ... when yr swinging over the place with a measuring tape, leaning over, etc ... there is the possibility that something will catch or bump
In which case you are talking about forcing the cam open. Wink

bearbreeder wrote:
youre obviously too LAZY to take a few seconds to tie a knot with your partners life on the line ... do you even let them know youre going to take your hand off the brake ???? ... or do you make that decision for em without informing em
No you are just making stuff up. Crazy


bearbreeder


Dec 22, 2012, 4:51 AM
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USnavy wrote:
I never said anything like that. I said the GriGri in my slackline is able to hold a load without a hand on the rope. I always keep my hand on the rope when belaying - no exceptions.

well if its 100% safe like some people claim ... then why bother putting your hand on the rope then ????

hint ... because things can go bump and catch ... Wink


bearbreeder


Dec 22, 2012, 4:52 AM
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Re: [patto] Video: Testing FF2 with dyneema [In reply to]
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patto wrote:
bearbreeder wrote:
oh GOD mista PATTO ... i just explained it to you ... when yr swinging over the place with a measuring tape, leaning over, etc ... there is the possibility that something will catch or bump
In which case you are talking about forcing the cam open. Wink

bearbreeder wrote:
youre obviously too LAZY to take a few seconds to tie a knot with your partners life on the line ... do you even let them know youre going to take your hand off the brake ???? ... or do you make that decision for em without informing em
No you are just making stuff up. Crazy

100% safe ???? ... lol

things can catch on the handle or bump the cam ... its THAT simple Tongue

which is what the video of the OP was doing ... swinging, leaning, clothing getting close to the lever, measuring tape on the air ...

unlikely but no more so than a fcukang true factor 2 fall without a belay device on some weird dyneema anchor Wink


(This post was edited by bearbreeder on Dec 22, 2012, 4:59 AM)


Partner rgold


Dec 22, 2012, 8:30 AM
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Re: [jliungman] Video: Testing FF2 with dyneema [In reply to]
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jliungman wrote:
The proportion of nylon vs dyneema would be an obvious starting point for some serious tests. The sling in the video was a Mammut, as far as I know. What model, I donīt know.

The thin Mammut slings have mostly white fibers and so probably have a relatively high ratio of dyneema to nylon. The slings DMM broke were also of the mostly-white variety. The slings Mal tested (which withstood factor-2 falls on clove hitches IIRC) were what Trango was calling "Ultratape" at the time and looked like the top picture in acorneau's post, i.e. perhaps a 50-50 mix.


namoclimber


Dec 22, 2012, 10:30 AM
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Re: [bearbreeder] Video: Testing FF2 with dyneema [In reply to]
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The gri gri is a fairly safe device for hands free. That being said, I have worked in a climbing gym for 15 years and can tell you I always tie a back up knot below the device just in case. In that time i have only had one issue with the device slipping and was caught by the knot.
Enough said. Be safe, be smart.
(all it takes is to unweight the device and it will slip)


USnavy


Dec 22, 2012, 3:59 PM
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Re: [bearbreeder] Video: Testing FF2 with dyneema [In reply to]
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bearbreeder wrote:
USnavy wrote:
I never said anything like that. I said the GriGri in my slackline is able to hold a load without a hand on the rope. I always keep my hand on the rope when belaying - no exceptions.

well if its 100% safe like some people claim ... then why bother putting your hand on the rope then ????

Wink
You are talking about two different phenomena. The GriGri may be able to support a load without assistance once the cam is locked, but you need to hold the rope to initiate the locking of the cam. That is why I hold the rope. Without drag on the brake side of the rope, the rope can slide through the GriGri on a fall without locking.


bearbreeder


Dec 22, 2012, 4:16 PM
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Re: [USnavy] Video: Testing FF2 with dyneema [In reply to]
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USnavy wrote:
You are talking about two different phenomena. The GriGri may be able to support a load without assistance once the cam is locked, but you need to hold the rope to initiate the locking of the cam. That is why I hold the rope. Without drag on the brake side of the rope, the rope can slide through the GriGri on a fall without locking.

actually im talking about when the cam is fully engaged and your climber is resting on the rope ... why bother keeping your brake hand on or trying it off ...

again ... hint ... things can get bumped or catch on the lever Wink


namoclimber wrote:
The gri gri is a fairly safe device for hands free. That being said, I have worked in a climbing gym for 15 years and can tell you I always tie a back up knot below the device just in case. In that time i have only had one issue with the device slipping and was caught by the knot.
Enough said. Be safe, be smart.
(all it takes is to unweight the device and it will slip)

i agree its generally pretty "safe" ... but all it takes is having one issue without the backup/brake hand and youre bear food ... or even worse or better, your partner is


patto


Dec 22, 2012, 4:28 PM
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Re: [namoclimber] Video: Testing FF2 with dyneema [In reply to]
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namoclimber and USnavy have hit the nail on the head.

Also note, for any other people reading this, nobody here has advocated NOT tying backup knots. All that has been claimed is that under some conditions the GriGri will securely hold without needed a brake hand.


bearbreeder


Dec 22, 2012, 4:50 PM
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Re: [patto] Video: Testing FF2 with dyneema [In reply to]
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patto wrote:
namoclimber and USnavy have hit the nail on the head.

Also note, for any other people reading this, nobody here has advocated NOT tying backup knots. All that has been claimed is that under some conditions the GriGri will securely hold without needed a brake hand.

unless something goes bump or catches ... which is very possible with the guy swinging, leaning, playing with tapes, etc .. in the video

i think other people who read this know pretty well thats quite possible ..

its basic safety procedure ... which is ironic in a video about the safety of gear

Wink


jliungman


Dec 23, 2012, 7:36 AM
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Re: [bearbreeder] Video: Testing FF2 with dyneema [In reply to]
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bearbreeder wrote:
patto wrote:
namoclimber and USnavy have hit the nail on the head.

Also note, for any other people reading this, nobody here has advocated NOT tying backup knots. All that has been claimed is that under some conditions the GriGri will securely hold without needed a brake hand.

unless something goes bump or catches ... which is very possible with the guy swinging, leaning, playing with tapes, etc .. in the video

i think other people who read this know pretty well thats quite possible ..

its basic safety procedure ... which is ironic in a video about the safety of gear

Wink

Was i not 100% clear in my previous post that the guy has a backup knot out of view? Why make assumptions based on a few seconds of vid? Can we stick to the topic instead?


bearbreeder


Dec 23, 2012, 11:29 AM
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Re: [jliungman] Video: Testing FF2 with dyneema [In reply to]
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my apologies then Wink

now go put a belay device in the system ... when was the last time you belayed up a pitch without one, or a munter/hip belay

Tongue


(This post was edited by bearbreeder on Dec 23, 2012, 11:34 AM)


Syd


Dec 23, 2012, 12:25 PM
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Re: [USnavy] Video: Testing FF2 with dyneema [In reply to]
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USnavy wrote:

You are talking about two different phenomena. The GriGri may be able to support a load without assistance once the cam is locked, but you need to hold the rope to initiate the locking of the cam. That is why I hold the rope.

In reply to:
nobody here has advocated NOT tying backup knots.

It seems some are suggesting that when the cam is locked, all is OK. All it takes for failure is a slight unloading by the climber, then a slowish re-uptake, especially with a new thin rope.


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