When to use screamers
|
-edit to remove reference to BD testing. I missed RGold's "analysis" previously. - |
|
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. |
|
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. |
|
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. |
|
rgold really like to type - or just cut n' paste the words of others. |
|
Rgold- |
|
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? |
|
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? |
|
I use screamers for my first two to three screws. A full rack of screamers would be heavy as hell. |
|
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. |
|
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. |
|
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. |
|
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. |
|
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: |
|
once again ... MP is a great place for telling other people how to climb their own climbs ;) |
|
Dana wrote: Check the definition of evidence.Sorry, can't do homework for you. |
|
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 ... =PBest post so far! |
|
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. |
|
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. |
|
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. |