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When to use screamers
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By rgold
From Poughkeepsie, NY
Nov 20, 2012
The traverse out to the Yellow Ridge on the Dogstick Ridge link-up.  Photo by Myriam Bouchard

Unless and until somebody can provide credible tests, I think screamers are an exercise in wishful thinking. To the extent that this is true, Dolgio (and Will Gadd's) position that they are just lipstick on an inadequate protection pig seem like the only rational approach.

The various testimonials are worthless, since they do not involve repeating the same situation without the screamer to evaluate what effect the screamer did or did not have. If screamers make you feel better about your pro, go ahead and use 'em, but understand that there is no good experimental evidence for their effectiveness on anything except very short falls, and elementary physics considerations guarantee that they cannot reduce the loads significantly when long falls are involved.

The most interesting experimental results about screamers in the the climbing context are the drop tests done by the CAI (www.caimateriali.org/homepage.html , but I can't find the article at this point) [Edit: the article is at www.caimateriali.org/index.php?id=27], tests that suggest that screamers are not effective in reducing peak loads when their full deployment is not enough by itself to absorb all fall energy. In other words, if the screamer fully deploys and then the rope has to stretch further to stop the fall, there appears to be little benefit to having had the screamer present at all. As far as I know, the CAI tests are the only ones that used a real belayer rather than just tying off the rope to an anchor and so providing a totally static belay.

Beware of the pseudo-physics arguments in places like the Yates site, which, after admitting that there does not seem to be any good explanation for so-called "observations" about screamer performance, advance the idea that screamers work by making the fall arrest take more time. The fall isn't going to stop until all of its potential energy has been absorbed. Energy is the area under the graph of tension vs. stretch, not tension vs. time (impulse). So, for example, it takes more time to stop a long factor-1 fall than it does to stop a short factor-1 fall, but the peak loads are the same. Time isn't the issue, except in the secondary sense that it takes longer for more stretching to happen.

In the case of long falls, it is obvious without experiment that screamers will have a negligible effect, because the fraction of the fall's potential energy the screamer can absorb is small and so the majority of energy absorbtion still falls to the rope. But the CAI tests suggest that even in more moderate falls the screamer is not much help. The most optimistic perspective on screamers says that they will reduce the load on the anchor to the level obtained by a fall that is 3 feet shorter. This is good news for, say, a five foot fall, but insignificant for a 20 foot fall (waist 10 feet above the pro), and ignores the CAI testing, with real belayers, that suggests that screamers might, in low-friction conditions, short-circuit load-reducing slippage in the belay device and so end up doing nothing or even increasing peak load.

The BD tests cited upthread seem to me to confirm this, as well as reveal some fundamental misunderstandings on the part of the BD engineers involved. Gauging the seriousness of a fall by using the fall factor is appropriate when the mode of energy absorbtion is the rope, which can be treated, to a first approximation, as an elastic medium that is scalable (more or less rope can be involved in the fall arrest). A screamer is neither elastic nor scalable. It is capable of absorbing a fixed amount of fall energy, basically its activation load times the length of the extended screamer. If this fixed amount of energy is a significant fraction of the total fall energy, the screamer will be effective, otherwise not, and so the only thing that matters for screamer effectiveness is the fall height, not the fall factor. The BD tests are almost a joke, because in order to "detect" screamer effectiveness they have to use falls so short you could basically grab the pro. Those tests tell you nothing about the performance of screamers in any situation beyond the shortest aid fall, and in particular provide no evidence about what would happen for longer falls of the same fall factor.

From Jim Titt:

"With screamers there are three camps amongst the manufacturers. There are those who promote them as the answer to everything and make claims which even the most deluded find a bit dubious. Then there are those who hum and haw around the benefits with plenty of "cans" and "mays" (the Petzl website is a masterpiece for this). Then there are the ones who never got them to work, got pissed off with the whole business and donīt make them, who are incidentally in the majority.

From my chats with the technicians in industry the most positive thing you will hear is "they might help" which is not exactly a positive endorsement. Some, who have spent a long time trying different sewing patterns and cold days on the test rigs are less charitable.

Since there is no UIAA/CE test for these things all we can fall back on is our intuition, a bit of private testing, some back of the envelope calculations, information leakage from the industry and the Italian testing which was about as complete and credible as we can hope for at this stage. From all these the manufacturers claims donīt come out well and some braver souls such as myself would be prepared to brand them as hype or worse to sell an effectively worthless product.

Since the issue has been open for many years and no manufacturer has ever published any verified test results from an independent test laboratory to clearly establish where the undeniable benefits of screamers stop and the undeniable negative aspects start, then I feel the public can say or do what they think and so they should.

Time perhaps for one of the manufacturers to step up to the plate?"


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By clay meier
Nov 20, 2012
Thats Me

I know that this is a very sciency and pompous forum and my question is simple but... I had a buddy fall on a screamer which only partially deployed (about half of the threads popped). In this instance, didnt the screamer absorb enough energy to make it so that the remaining threads did not receive enough force to pop? If this is the case, didnt that absorbtion of energy create less load on the piece of pro?


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By Darren Mabe
From Flagstaff, AZ
Nov 20, 2012
wham bam hand jam. Wrapping up the final moves of Twist of Fate, Oak Creek Canyon. <br /> <br />photo: Blake McCord

clay meier wrote:
I know that this is a very sciency and pompous forum and my question is simple but... I had a buddy fall on a screamer which only partially deployed (about half of the threads popped). In this instance, didnt the screamer absorb enough energy to make it so that the remaining threads did not receive enough force to pop? If this is the case, didnt that absorbtion of energy create less load on the piece of pro?

that has been my reasoning on the topic. i have partially deployed screamers on three different falls, one being on a pin in a flake. thats the only data i need.


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By kennoyce
From Layton, UT
Nov 20, 2012
Climbing at the Gallery in Red Rocks

clay meier wrote:
I know that this is a very sciency and pompous forum and my question is simple but... I had a buddy fall on a screamer which only partially deployed (about half of the threads popped). In this instance, didnt the screamer absorb enough energy to make it so that the remaining threads did not receive enough force to pop? If this is the case, didnt that absorbtion of energy create less load on the piece of pro?


yes, but probably not significantly less load. Like Rgold mentioned, it all has to do with the length of the fall, but if it was a normal lead fall (i.e. more than a couple of feet) then it was probably not much of a reduction. If the screamer partially deployed than we know that the force on the piece of pro didn't exceed the screamer's activation force. I don't know what screamers activate at these days (and don't really care to look), but let's say that they activate at 5 kN, the partially deployed screamer probably reduced the peak force from something like 5.1 kN down to 5.0 kN.


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By Larry S
Nov 20, 2012
The wife and I road-trippin on the Connie.

clay meier wrote:
I know that this is a very sciency and pompous forum and my question is simple but... I had a buddy fall on a screamer which only partially deployed (about half of the threads popped). In this instance, didnt the screamer absorb enough energy to make it so that the remaining threads did not receive enough force to pop? If this is the case, didnt that absorbtion of energy create less load on the piece of pro?


Yes. In that case it limited the load transferred to the piece to the activation force of the screamer. Think of it as a load limiter. So long as it has stitches left to tear it transmits a maximum of ~500lbs force. Once fully deployed, if there is still significant energy from the falling climber, the load on the protection will likely increase. The biggest thing i've taken from reading this is we don't have enough data to really understand what happens in the system once the screamer is fully deployed. The best estimate is it effectively "shortens" the fall by about 3'.


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By superkick
From West Hartford, CT
Nov 20, 2012
Free Solo up hitchcock gully WI3

the best advice is just dont waste time placing dubious gear. when in doubt run it out.


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By Tits McGee
From Boulder, CO
Nov 20, 2012
How I Send

To all of those involved in this inane rambling thread...


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By rgold
From Poughkeepsie, NY
Nov 20, 2012
The traverse out to the Yellow Ridge on the Dogstick Ridge link-up.  Photo by Myriam Bouchard

clay meier wrote:
I know that this is a very sciency and pompous forum and my question is simple but... I had a buddy fall on a screamer which only partially deployed (about half of the threads popped). In this instance, didnt the screamer absorb enough energy to make it so that the remaining threads did not receive enough force to pop? If this is the case, didnt that absorbtion of energy create less load on the piece of pro?


Since the screamer didn't fully deploy, we know that it wasn't called on to absorb much fall energy. If the screamer absorbed all the fall energy, then the fall would have to have been short, and in that case the load to the anchor would probably have been reduced significantly, as in the BD tests.

If it wasn't a pretty short fall, than some other agent must have intervened to absorb fall energy, for example the rope slipping at a tension below the activation threshold of the screamer. In that case, whether the screamer had a significant effect or not would depend on the actual fall length; the longer the fall the less effect the screamer would provide.


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By patto
Nov 20, 2012

To slightly elaborate. (Though I think rgold's comprehensive analysis covers pretty much everything.)

Screamers take time to fully deploy they don't deploy instantly. If it takes 0.2ms to deploy and the rope tension at/above the threshold force only lasts for 0.1ms then you would end up with a approximately half deployed screamer.

ie, A partially deployed screamer simply indicates a short time at/above threshold force. And a small amount of energy absorbed by the screamer.


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By bearbreeder
Nov 21, 2012



i have 2 of these that i use above micro cams, RPs and manky pins that are sometimes the only gear you have on some climbs ...

do they work? ... who knows ... but anything in said situations that reduces the fall forces on said sketchy gear is a bonus when its between you and the ground ...

as a bonus they are reusable ... so you arent paying 20$ per pop ;)

oh and i scream alot as well =P


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By Kevin Craig
Nov 21, 2012
KC on Fields (medium).  Photo (c) Doug Shepherd

-edit to remove reference to BD testing. I missed RGold's "analysis" previously. -

Not sure that he provides any more insight than those he criticizes. He wants data then argues the data isn't good enough when it contradicts his beliefs.

I use screamers somewhat regularly to stack the odds in my favor because I'm a big guy and if they reduce the "effective" fall (his term) by even 3 feet out of 20, it might be enough to save my butt.

If you believe in 'em, use 'em, if you don't, don't. I don't think ANYONE is going to intentionally place shitty gear just because they use screamers. Nor are screamers going to CAUSE a problem if they don't work as intended - they just might not prevent one.

Is there really anything more to discuss???


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By Reginald McChufferton
Nov 21, 2012

Kevin Craig wrote:
Not sure that he provides any more insight than those he criticizes. He wants data then argues the data isn't good enough when it contradicts his beliefs.


what thread have you been reading? Obviously not this one.


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By Kevin Craig
Nov 21, 2012
KC on Fields (medium).  Photo (c) Doug Shepherd

Uh yeah, I have been. He refutes what he calls anecdotal evidence and opinion with anecdotal evidence and opinion. I'm done here. Everyone do what you want.


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By rgold
From Poughkeepsie, NY
Nov 21, 2012
The traverse out to the Yellow Ridge on the Dogstick Ridge link-up.  Photo by Myriam Bouchard

Kevin Craig wrote:
He refutes what he calls anecdotal evidence and opinion with anecdotal evidence and opinion. I'm done here. Everyone do what you want.


Just for the record: I didn't cite even a single piece of anecdotal evidence. Not one. My only references to "evidence" were to the BD tests and those conducted by the CAI Commissione Centrale per i Materiali e le Tecniche, tests that many people I know and talk to have read, although I was frustrated by my inability to find a link to them when I posted (I'm still looking). [Edit: Found the reference. See www.caimateriali.org/index.php?id=27.] In any case that part of KC's objection is completely without merit and in fact without content.

As for the opinion part, I am, of course, giving an opinion, as is everyone else and KC in particular. Presumably, opinions are a large part of what such forums are about. But the opinions I've given come with supporting physics arguments, which I have tried to keep non-technical---and even so have been obliquely criticized for being "sciency" and "pompous," the message being, I suppose, that one shouldn't actually explain one's conclusions. In any case, opinions with supporting arguments can be argued against by showing the supporting arguments are flawed, but that hasn't happened yet with anything I've said.

Both the BD tests and basic physics suggest that screamers will reduce anchor loads for very short falls. Once the falls are not short, there does not seem to be any reality-based reason why screamers will have more than a negligible effect. As Jim says, there is, in principle, a threshold after which there is little or no point in having a screamer in place, but we have almost no idea where that threshold is in practice. The best we have that I know of is the theoretical calculation that a fully-deployed screamer at best will produce anchor loads corresponding to a three-foot shorter fall.

I used to believe in the "it can't hurt" approach myself---I own and have used screamers---but in the CAI tests some of the loads came out higher with screamers. I don't think anyone knows for sure why, but one theory is, as I said, that rope slippage through the device, inhibited by the partial energy absorbtion of the screamer, would actually have been more effective in reducing the load to the anchor than the screamer was. There are some other possible explanations which I'm not going to try to explain here.

This suggests that climbers who are using either a Gri-gri or one of the recent crop of locking belay devices (Mammut Smart, Climbing Technology Click Up), who will not benefit from rope slippage through the device, might be better served by a screamer. But, unlike my previous arguments, this is pure speculation.

The strongest voice I've heard arguing for screamers comes from Joe Healy. Here is one of his more forceful statements:

"I can personally testify to their benefit in marginal free climbing protection. I've gone through dozens of them in free climbing falls in the kind of Edisonian research that counts. I've ripped them partially and completely. I razor blade them down at a varying angles to adjust their initial loading to suit the placements and sport tape partially blown ones back together for multiple goes. They are absolutely key to marginal pro. I've taken many multiple dives onto nests of RPs / Crack N Ups / #1-3 Loweballs that would never hold a fall otherwise."

You can find this, responses to it, and other interesting points in the thread at rockclimbing.com.nmsrv.com/cgi-bin/forum/gforum.cgi?post=250>>>.

Although I don't buy Joe's arguments or conclusions, there is one aspect about screamers, hidden in the quote above but, I think, revealed in the referenced thread, that might deserve more attention, and that is the use of screamers to equalize loads to multiple anchor points.


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By Tits McGee
From Boulder, CO
Nov 21, 2012
How I Send

rgold really like to type - or just cut n' paste the words of others.

I agree with Kevin Craig on this one. Use em or Don't - who cares??? They inspire confidence and sometimes that's what you need to get up the climb.


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By Derek Doucet
Nov 21, 2012

Rgold-

Despite the pejorative use of non-words such as "sciency" (oh the irony) by others here, I for one sincerely appreciate your thoughtful and measured contributions both to this thread and this forum in general.

Cheers.


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By rgold
From Poughkeepsie, NY
Nov 21, 2012
The traverse out to the Yellow Ridge on the Dogstick Ridge link-up.  Photo by Myriam Bouchard

Thanks Derek.

Tits McGee wrote:
They inspire confidence and sometimes that's what you need to get up the climb.


...and other times it is what you need to take a dangerous or fatal fall unto inadequate gear.

So if you could paint a bolt and quickdraw on the rock so that it looked as if you had protection where none was in fact available, would the confidence inspired by this illusion also be a good thing?


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By Tits McGee
From Boulder, CO
Nov 21, 2012
How I Send

rgold wrote:
So if you could paint a bolt and quickdraw on the rock so that it looked as if you had protection where none was in fact available, would the confidence inspired by this illusion also be a good thing?


Depends if you could paint in the photo realistic style...

Obviously, rGold, I didn't mean to become collateral damage in your war against screamers. All I was implying is that sometimes, "psych pro" helps you stay focused on the task at hand and less worried about the pro or lack there of below. It seems that it will be a personal preference when or if to use screamers, yours is clear.

To reinforce the first rule of ice climbing - you don't fall, so it doesn't matter what's clipped to your last screw, right?


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By divnamite
From New York, NY
Nov 21, 2012

I use screamers for my first two to three screws. A full rack of screamers would be heavy as hell.

If you read Richard's long ass posts (sarcasm here), there is no evidence of screamers not working, and some "debatable" evidence of screamers working. So... my suggestion, keep using screamers until proven otherwise.


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By rgold
From Poughkeepsie, NY
Nov 21, 2012
The traverse out to the Yellow Ridge on the Dogstick Ridge link-up.  Photo by Myriam Bouchard

Divnamite, if you really do read my long-ass comments, you will find that there is specific evidence of screamers not working and even of them making the situation worse. The tests were done by a highly reputable big European climbing organization with resources far beyond what anyone in this country could dream of. Whether they are conclusive or not will depend on further confirmation tests.

Tits, you're the one who posted a video comment that begins with "What you've just said is one of the most insanely idiotic things I've ever heard." The only war going on is the one you promoted, and offensively at that.

And I am not on a war against screamers. I own them and have used them, and would again for specific applications to very short falls, where there is a chance they might help. Moreover, I am open to opposing theoretical arguments or credible testing that suggests I'm wrong. I'm interested in the truth, not in advancing one version or another of it. I posted Joe Healy's comments contradicting everything I said and gave a link where more of his opinions could be read. I'm interested in understanding my gear rather than making uncritical general assumptions about it's effectiveness. And if the answers take a while to type or are illuminated by what others have said, I'm willing to do that too.


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By patto
Nov 21, 2012

Bringing up the "it can't hurt" arguments starts to sound similar to arguments made by people defending homoeopathy or other 'junk' medicine in the face of scientific arguments.

While absolutely and clearly useless, homoeopathy worse effects most of the time is lightening the wallets of the users. However the false hope can lead to sub optimal decisions with occasionally severe consequences.

Science and evidence based research has been the basis of the modern world's technological growth with obvious benefits for mankind. It is frustrating to see people ignore it so willingly.


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By Tits McGee
From Boulder, CO
Nov 21, 2012
How I Send

Goldie, that video wasn't aimed at you, but more the back and forth before your posts. Sorry to offend, glad you like to type and/or not use screamers, because in the end, I really don't care what you think about your gear. Your posts never really presented any evidence large enough to not clip a screamer, so I will keep using mine. Thank you for your thoughtful posts. Climb Safe.


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By Dana Bartlett
From CT
Nov 21, 2012

This thread reminds me of the silicon breast implant liability lawsuit. The argument that the plaintiffs offered for the implants being the cause of the damages they suffered was, essentially: "I don't need evidence, and I don't need proof; I just know."


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By divnamite
From New York, NY
Nov 21, 2012

rgold wrote:
Whether they are conclusive or not will depend on further confirmation tests.

If it's not conclusive, then how can you say it's evidence?

Anyway, I have no issue with what you posts since it's personal opinion. My posts offer my opinion of using the screws for the first two or three screws.


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By Dana Bartlett
From CT
Nov 21, 2012

divnamite wrote:
If it's not conclusive, then how can you say it's evidence? Anyway, I have no issue with what you posts since it's personal opinion. My posts offer my opinion of using the screws for the first two or three screws.


Check the definition of evidence.


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