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TKingsbury
Trad climber
MT
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Dec 11, 2007 - 12:32pm PT
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Screamer nest or not, I wouldn't wanna fall from here!
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Holdplease2
Big Wall climber
Yosemite area
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Dec 11, 2007 - 12:35pm PT
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Specially not with that rope around the leg. Ouch!
-Kate.
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TKingsbury
Trad climber
MT
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Dec 11, 2007 - 12:38pm PT
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His leg/rope position is actually optimal, not wrapped nor between the legs, which would cause a flip.
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ec
climber
ca
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Dec 11, 2007 - 12:50pm PT
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"The bar tack ones that Kate might be talking about (where the bartack goes across the webbing instead of long ways down the webbing) will give you a very exciting gate flutter on a carabiner during load.... if you hit the end of the screamer while the gate is open..... oh well... broken biner. I believe that is why Yates and WildThings quit making them that way. YMMV" - Russ
If I remember correctly, there was a lawsuit filed against Wild Things over the use of the bar tacks. The accident occurred on an ice climb, the leader fell (unusual for ice IMHO) and the carabiner supposedly broke due to the gate flutter caused by the loading and unloading of the bar tacks ripping. The leader ended up breaking both ankles. When I worked at Sunrise Mountain Sports, some guy discreetly ordered bought at least 40 of them. I later found out that he was an investigator on this and was testing them concerning this accident.
 ec
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ec
climber
ca
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Dec 11, 2007 - 12:55pm PT
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rgold,
The still present flutter on the Yates screamers is apparently minimized compared to the former design and not an issue.
The longer the fall, the more rope you're going to have to absorb the energy of the fall...You're mostly correct, for 'short falls' on crappy gear. A long fall on crappy gear, either way, you're on your own, if you think about it...
ec
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Holdplease2
Big Wall climber
Yosemite area
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Dec 11, 2007 - 12:56pm PT
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Hmmm....OK, then,
So holding the rope behind your heel off to one side is better than climbing straight above it?
I could be wrong, but it looks to me like if he dropped straight down in a fall right now, the rope could end up behind his left leg and pointing up from the back out through the front his crotch, giving him rope burn and flipping him upside down, resulting in a helmet test.
OTOH, If the rope was dropping straight down between his legs, it would simply rotate at and point straight up in the fall, which is what you want it do do, right?
-Kate.
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P.Kingsbury
Trad climber
Bozeman
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Dec 11, 2007 - 01:04pm PT
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me on the route....
the picture makes the route look less steep than it is...(and i don't know if the gear would hold anyways...)
by keeping the rope in front of my body (and leg) if i slipped my feet would drop down and the rope would still be in front of me, making for a regular fall (edit...i would be falling to my right, not left)
if the rope was between my legs (the rope would then be behind my leg and body), as you suggested, if i slipped the rope would most certainly go against my calf and flip me for sure.
i have learned my lesson before and hope to not do it again, since i take wingers some what often.
thanks for your input though
but are mammuts really worth paying over double for??
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TradIsGood
Recently unshackled climber
the Gunks end of the country
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Dec 11, 2007 - 01:26pm PT
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I am in the "depends on how he falls camp." To me, it looks like his left hand is the more solid of the two. If the right foot slips and he catches with his left hand briefly, his CG may swing slightly left and his whole body may rotate clockwise, which could send the left ankle further under the rope - that would not be good, especially compared to having rope in front of leg. It is somewhat likely the same thing but without as much extension occurs on a left foot slip, but a barn door might save him if that happened?
Of course, it is hard to know exactly what line is straight down in this picture.
But having the rope between the legs does raise the issue mentioned. It is certainly preferable for the foot to stay below the rope. Which it nearly is now.
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Holdplease2
Big Wall climber
Yosemite area
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Dec 11, 2007 - 01:30pm PT
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OK, that makes sense. Its hard to tell that from the pic about the angle, it almost looks overhanging. Time and a place for everything, right?
I solve my rope position problems by refusing to climb above my gear. Less thought, safer all round. ;)
Regarding the screamers: I got a dealio on the Mammuts, so they ended up costing about the same as the Yates. I do like that they are less bulky, which is worth something to me, but how much depends on my disposable income at the time. Sometimes that number is high, sometimes its low.
Its probably mostly matter of taste, which some people are willing to pay for while others aren't. However, I will say that Yates has far more extensive testing data on their web site, and moved away from bar tacks.
According to the Mammut web site, their device activates slightly over 2.5 kn and the yates screamer activates at under 2 kn. Something to think about. CORRECTION EDIT: Read the wrong...Yates activates at >2kn. But they do have the scream aid option.
-Kate.
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Holdplease2
Big Wall climber
Yosemite area
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Dec 11, 2007 - 01:39pm PT
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* Standard SCREAMER, SHORTY, ICE-SCREAMS: Activation: >2kN. Reduction in system peak loading 3-4kN. Runner Strength: 26kN.
* ZIPPER Screamer: Activation: >2kN. Reduction in system peak loading 4-8kN. Runner Strength:26kN. (KR - Because it is longer)
* SCREM AIDS: Activation:>1.5kN. Reduction in system peak loading 1.5-2kN. Runner Strength: 7kN. "use on extremely marginal aid placements only"
Just as FYI. From the Yates web site. Mammut should make more info available on theirs, IMO.
-Kate.
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TKingsbury
Trad climber
MT
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Dec 11, 2007 - 01:51pm PT
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good info. Thanks Kate
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rgold
Trad climber
Poughkeepsie, NY
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Dec 11, 2007 - 04:12pm PT
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ec wrote: "The longer the fall, the more rope you're going to have to absorb the energy of the fall...You're mostly correct, for 'short falls' on crappy gear. A long fall on crappy gear, either way, you're on your own, if you think about it..."
I'm happy to share the dubious distinction of being "mostly correct" with you! Allow me to attempt a recovery by being a bit more precise:
Suppose you have a long factor 0.5 fall and a short factor 0.5 fall. At least in theory, without a Screamer, both falls will result in the same peak load at the protection, even though (or precisely because) "the longer the fall, the more rope you're going to have to absorb the energy of the fall." If a Screamer is employed in both situations, it may reduce the short factor 0.5 fall peak load significantly, but it will have little effect on the long factor 0.5 fall peak load.
So even though the two falls have the same "severity," as measured by peak load to the protection, the Screamer only helps much on the short fall. The explanation for this does not involve the fact that there is more rope available for arresting the longer fall.
We do agree, as does everyone, I suppose, on the creek you're up with a long fall on crappy gear.
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Majid_S
Mountain climber
Bay Area
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Dec 11, 2007 - 04:56pm PT
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I have few images of yates in action which may change your mind from buying them
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John Mac
Trad climber
Littleton, CO
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Dec 11, 2007 - 05:06pm PT
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Please post them up!
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flamer
Trad climber
denver
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Dec 11, 2007 - 07:27pm PT
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I used to be completely sold on screamers. The I started talking to some folks who tested them independantly...now I'm not so sure.
A lot of what they said was along the lines of what rgold is talking about.
rgold knowing(and understanding!) much more about the physics of it then I.
I've heard a couple of other things about them....the length a fully deployed screamer adds to the fall coupled with the "spike" in peak force (return?) once it is fully deployed making them not effective...I'd love to hear what rgold has to say about this.
Also I hear rumors that the violent vibrations from screamer deployment can cause certain types of gear to "wiggle" out of the rock?? Can anyone elaborate on this?
josh
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rgold
Trad climber
Poughkeepsie, NY
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Dec 12, 2007 - 12:54pm PT
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Josh,
My gut feeling is that Screamers and their imitations are over-rated. I hesitate to say even this much because so many people are devoted to them and insist that they took such and such a fall that was held by a screamer looped over a toothpick and this canape rig would never have held otherwise. But none of these stories comes with a repeat of the test to see whether, in the same circumstances, the olive and toothpick might have worked all by itself, so none of the testimony I've read seems to have any substance. Still, I expect some serious flammage for even suggesting that if it isn't quite true that emperor has no clothes, he is probably at best rather scantily clad.
I'd love to see some independent tests. Without such confirmation, I find it hard believe the claim on the Screamer site that "standard Screamer and Shorty Screamer reduce peak forces on protection anchors by 3-4kN." No qualifications here about the reduced effect as the length of the fall increases. Nor does it help that Yates has admitted that his Screamer numbers are better than one should expect and has suggested some principles that don't make any sense to me to explain the discrepancy.
I too have heard, from time to time, about people making their own tests of Screamers and concluding that their effect in reducing peak loads is quite limited. But these tests tended to be home-made affairs with very few trials, and it wouldn't be right to base conclusions on them. Whenever I try to calculate the Screamer reduction effect theoretically, I too come up with very modest results. But theoretical calculations have their own limitations and cannot be considered conclusive either.
Here is a very rough but still illustrative way to think about their effect. Let's use a 180 lb climber for reference. Screamers activate at 550 lbf and elongate two feet, so are capable of absorbing about 1100 ft-lbs of fall energy. But they also add four feet to the fall distance, meaning they introduce an extra 180 X 4 = 720 ft-lbs of fall energy that will have to be absorbed by the system. Consequently, their net effect is to remove 380 ft-lbs of the fall energy the rope would have had to absorb if there had been no Screamer, and 380 ft-lbs is the energy that needs to be absorbed if our 180 lb climber falls a bit more than two feet. So very roughly speaking, the effect of a Screamer for a 180 lb climber is to produce the peak impact on the pro that would have occurred if the fall had been two feet shorter.
Shortening a three-foot fall to one foot will obviously confer a significant benefit, and this is where Screamers can be expected to shine. But shortening a twelve foot fall to ten feet is not going to make much difference, and you can see where this is heading after that. Of course, with bad pro, one might argue that any reduction in peak load, no matter how small, is a benefit. We often place bad pro with an argument like this in mind anyway, so why not increase our chances a bit more? Sounds reasonable to me, my only point is, just don't expect too much.
As for the other objections, I don't believe in the spike effect (but I guess I don't even know what that means) and I find the vibration extraction of gear very dubious at best.
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rgold
Trad climber
Poughkeepsie, NY
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Dec 12, 2007 - 04:15pm PT
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Del, thanks for the reference, I hadn't seen it. It does seem to confirm the idea that Screamers don't reduce peak loads by much. I wish I could read Italian...
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morse
Trad climber
CT
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Dec 12, 2007 - 06:00pm PT
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Russ is right about the whole carabiner gate whiplash deal that is caused by horizontal bartacks.
I was photographing New England climber Pat Hackett who was tearing up the R-rated testpieces at Ragged Mountain, Connecticut, one day.
At the top crux of RAGGED EDGE 5.10d R, he was climbing above a small RP nut (#2 or #3) clipped with a Wild Things AIR VOYAGER. Right at the hardest move, he fell.
There was a noise like a long, loud fart, but the nut held!
But then we checked out the bottom carabiner on the Air Voyager (it was an old oval SMC or Eiger biner). What happened is that the vibration caused the gate to swing open while the carabiner stretched from the force of the fall.
When the fall stopped, the gate of the carabiner was trapped on the outside of the oval!
Pat went right back up on the climb, reached his high point, clipped in a second sling to the RP and sent this proud route on his next go.
Later, three of us were standing on top trying to stretch the carabiner and pop the gate back in. It didn't work, but at least there's a memorable souvenir from the climb.
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