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When to use screamers

Kevin Craig · · Unknown Hometown · Joined Mar 2002 · Points: 325

-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???

Reginald McChufferton · · Unknown Hometown · Joined Sep 2012 · Points: 0
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.
Kevin Craig · · Unknown Hometown · Joined Mar 2002 · Points: 325

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.

rgold · · Poughkeepsie, NY · Joined Feb 2008 · Points: 526
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 caimateriali.org/index.php?….] 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/…;.

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.
Tits McGee · · Boulder, CO · Joined Apr 2008 · Points: 260

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.

Derek Doucet · · Unknown Hometown · Joined Apr 2010 · Points: 66

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.

rgold · · Poughkeepsie, NY · Joined Feb 2008 · Points: 526

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?
Tits McGee · · Boulder, CO · Joined Apr 2008 · Points: 260
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?
divnamite · · New York, NY · Joined Aug 2007 · Points: 90

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.

rgold · · Poughkeepsie, NY · Joined Feb 2008 · Points: 526

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.

patto · · Unknown Hometown · Joined Jul 2012 · Points: 25

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.

Tits McGee · · Boulder, CO · Joined Apr 2008 · Points: 260

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.

divnamite · · New York, NY · Joined Aug 2007 · Points: 90
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.
rgold · · Poughkeepsie, NY · Joined Feb 2008 · Points: 526

I found the link to the CAI tests: caimateriali.org/index.php?… You'll have to read Italian or struggle through the results of Google Translator. Here is the translation of their summary of the tests of screamer-type load limiters:

1. Commercial shock-absorber

...But - of most interest to climbers - the lack of utility for the purpose of reducing the load on the last anchor point was also confirmed, as is clear from the results of dynamic tests. In all test conditions, in fact, the presence of the shock-absorber was practically irrelevant, in the sense that the reduction of the load on the anchor was almost always insignificant or at most - under high loads (approx. 800 kp) and mild activation of the belay device - very low.

In the light of its poor ability to absorb energy, it is considered that this tool can be of some utility only when the overall energy involved is relatively low, ie in case of drop heights of a few meters (eg a fall from 1 m above the top piece).

So in more practical terms, the screamer may be of some use until the pro is below your feet, after which its contribution to load reduction is negligible. Perhaps I'll post more about what the tests say, including the observation of an increase in anchor load, but I must attend to some other things first.

A happy Thanksgiving to all, whether you believe in screamers or not.

bearbreeder · · Unknown Hometown · Joined Mar 2009 · Points: 3,065

once again ... MP is a great place for telling other people how to climb their own climbs ;)

god i luuuv the intrawebs ...

dont use PAS, dyneema, evolve defies, ATC guides, gri gris, screamers etc ...

in real life people just go out and use what they want ... =P

divnamite · · New York, NY · Joined Aug 2007 · Points: 90
Dana wrote: Check the definition of evidence.
Sorry, can't do homework for you.
divnamite · · New York, NY · Joined Aug 2007 · Points: 90
bearbreeder wrote:once again ... MP is a great place for telling other people how to climb their own climbs ;) god i luuuv the intrawebs ... dont use PAS, dyneema, evolve defies, ATC guides, gri gris, screamers etc ... in real life people just go out and use what they want ... =P
Best post so far!
patto · · Unknown Hometown · Joined Jul 2012 · Points: 25

Those figures are pretty damning of the performance of screamers. But unfortunately it seems people are here to argue their opinions rather than discussing the truth.

Larry S · · Easton, PA · Joined May 2010 · Points: 872

I know this is beaten to death on here and i'm just going to stoke the fire for more argument/nasty responses, but i have been pondering the math of and decided to write up little essay anyways, it might be of value to someone. If it's not for you, ignore and carry on... so here's a little physis i scribbled on my notepad. It's probably close. There are alot of assumptions.

Assuming a 2.4kn activation force (550 lbs), and an extension of 30cm (~12"), and assuming the the deployment is not in discrete steps as the stitches tear, fully deploying a screamer should take ~734 Joules of energy (2446N * .3m)

Now, we can figure out how high a mass must be to have a potential energy capable of generating that much energy U= m(mass) * g(acceleration by gravity) * h(height). Assuming a mass of 80kg (~175lbs), we find a fall of .93 meters has that much energy. That's almost exactly 3 feet. Now, this imagined scenario is a perfectly system, nothing is considered aside from the perfectly static anchor, the screamer, and the falling mass. Nothing extends or shifts to spread the energy over a longer duration of time/distance other than the screamer. Think of a steel mass falling onto a dynema daisy or steel cable connected to a bolt with a screamer in between. (note that this is 3' from the time the fall starts to the time the fall is completely arrested, w/ the screamer deployed - it's really a 2' fall onto the screamer + elongation of the screamer)

This is probably why they say that the screamer effectively shortens a fall length (as seen as force on the anchor) by 3', it absorbs the energy of a 3' static fall. Any falls greater than this have more energy, and when we add in the dynamics of a belay, dynamic rope, etc, it's a very complicated system with interactions between the different parts. It's quite probable that having the screamer in the system affects the dynamics of how the rope/belay work with longer falls, so it's hard to say how effective they are. For short falls, they definitely have potential to limit the load. For longer falls, they dissapate some of the energy early on, but we don't know what happens after it's fully deployed. From the Yates and BD data, they look to help, though the BD data shows not as much as Yates claims. The yates data doesn't really tell us anything about how they tested it, and the BD tests have a static belay and don't show any long/low FF falls.

If we really wanted to see how this works, we'd need to get a setup like user "20kn" had for seeing the loads generated in bounce testing and about a dozen screamers, and plot out the load as a function of time for different fall lengths with different fall factors for systems with and without screamers and analyze them.

Also want to point out to the "useless in realistic/long falls" crowd that Yates does make screamers called "zippers" with double the extension/stitching to tear that are meant specifically for longer/higher fall factors, and they'll probably effectively reduce the fall length (as seen as force on the anchor) by 6'

Another thing worth pointing out is, assuming the rope/belay system acts the same with or without the screamer, the ~1' extension of the screamer, or ~2' in the case of he zipper, makes you stop your fall 2' and 4' closer to the ground, respectively.

Danger-Russ Gordon · · Salt Lake City, UT · Joined Nov 2011 · Points: 590

Since we are on the hypothetical side of this debate in some respects, could you, hypothetically, connect several screamers, and if so would the advantages of force reduction be multiplied respectively to how many screamers you added? Just wondering if anyone has thoughts on that, I know its ridiculous.

Guideline #1: Don't be a jerk.

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