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ubotch
Mar 2, 2003, 12:42 AM
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Anybody out there use screamers when you are climbing trad? I was thinking about getting a couple for use on marginal placements and for the first placement off of a belay on multi-pitch climbs to keep that fall factor low. Is this a good idea?
Also, do you have any recommendations on which one to get? The zipper screamer is about twice as much as the screamer. Does that mean its twice as good or what? Thanks for any feedback.
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boltdude
Mar 2, 2003, 1:27 AM
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Yep, all the time. Any thin nuts, thin cams, marginal placements, bad bolts, iffy pitons, or just the first piece off the belay.
Zippers are double-length Screamers, and are better for the first piece off the belay and higher fall-factor falls. However, they are also heavier. I only bring them for trad routes with long runouts or lots of thin pro (or bad bolts).
Screamers are lighter, but are less effective with big falls.
If I'm heading to do something where I can reasonably expect a lot of thin pro, long runouts, or serious falls, I bring Zippers; otherwise Screamers. But I have a ton (4 each) and can bring whatever I want. I'd recommend one Zipper and 1 or 2 Screamers for a standard Trad rack, especially since a lot of trad routes still have 1/4" bolts at face sections.
Greg
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tanner
Mar 2, 2003, 3:08 AM
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Have you ever fallen on a screamer? if so how well did it work?
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flamer
Mar 2, 2003, 10:38 PM
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Keep in mind that standard screamers(including the zipper) do not activate until they have a force of 2 Kilonewtons(Kn). So on truly marginal piece's (like old mank bolts or tiny RP's) there is a good chance the piece will blow before the screamer activates. Now I 'm not saying that it's not a good idea to use them! What I am saying is for extremely marginal piece's you may want to use an "aid scream" and then a standard screamer. Aid scream's will activate at 1Kn, but will not absorb as much force. If you use both in conjunction(ie a "chain") you increase the over all shock absorbtion.
Just another tool for your box.....
josh
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rgold
Mar 4, 2003, 1:49 AM
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In reply to: Keep in mind that standard screamers(including the zipper) do not activate until they have a force of 2 Kilonewtons(Kn). So on truly marginal piece's (like old mank bolts or tiny RP's) there is a good chance the piece will blow before the screamer activates.
It is incredibly easy for a belayed leader to develop a 2 kN load on a piece. Even allowing for the effect of friction over the carabiner, the piece will get a 2 kg load if the tension in the rope reaches 1.2 kg. An 80 kg belayed leader can achieve more than that by taking a "fall" of height zero, in other words, by suddenly weighting a rope with no slack in it leading to the top piece. The "fall" is just the rope stretch in this case, and the tension in the rope will be twice the weight of the climber, or 2 times 0.78 kN = 1.56 kN. (This result is independent of how elastic the rope is, assuming it is not perfectly rigid.) If this "fall" is held by a belayer, then the piece is subjected to a 2.6 kN load, which will activate the screamer. If your RP can't even hold a fall of height 0, it is really manky! There is virtually no chance that a piece will blow before a screamer activates if the fall is held by a belayer.
You don't need a scream aid for any belayed situation. Scream aids are for aid climbing, obviously, and in particular they are meant to save your butt when you fall (or bounce too hard) on your daisy chain. In this case, there is no "load doubling" effect on the top biner, and you need activation at 1.5 kN to keep a piece from pulling under sudden imposition of body weight.
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piton
Mar 4, 2003, 2:00 PM
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yup, sure do you screamers. i use a screamer on pro that i feel is a marginal placement. oh yes i have fallen on a screamer once, the fall ripped open the screamer half way.
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pywiak
Mar 4, 2003, 3:19 PM
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I fell on a screamer once. It was attached to a sling on a tied-off knob in Tuolumne. The results: the screamer unzipped completely. thereafter transferring full force to the tied-off knob. Next, the sling snapped (I think the knob is still there). Finally, the entire energy absorption/failure event set up a biner gate vibration that unclipped the screamer/sling from the rope. I found it later at the foot of the wall. It didn't even slow down my fall. In my opinion, their energy absorption capacity makes them unsuitable for free climbing use.
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rgold
Mar 4, 2003, 4:14 PM
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In reply to: I fell on a screamer once. It was attached to a sling on a tied-off knob in Tuolumne. The results: the screamer unzipped completely. thereafter transferring full force to the tied-off knob.
If the screamer unzipped completely, it reduced the load the knob would otherwise have received by 3-4 kN. (If the screamer was a zipper screamer, the load reduction would be 4-8 kN.)
In reply to: Next, the sling snapped (I think the knob is still there).
Must have been a very high fall-factor fall, and/or else the knob had a sharp edge, or perhaps the knob did break---you don't seem to be sure.
In reply to: Finally, the entire energy absorption/failure event set up a biner gate vibration that unclipped the screamer/sling from the rope.
The gate must have unclipped after the sling broke (as you say), because otherwise the sling wouldn't have broken. But then it couldn't have been vibration set up by the screamer ripping that opened the gate. Once the sling broke, you have a falling quickdraw that is banging the carabiners against the rock, and it would have been those impacts that caused the unclipping.
In reply to: I found it later at the foot of the wall. It didn't even slow down my fall.
It did slow your fall, in the sense noted above.
In reply to: In my opinion, their energy absorption capacity makes them unsuitable for free climbing use.
Screamers reduce the maximum load on the top piece. In your case, the load reduction wasn't enough. This does not mean that there won't be many instances in which the load reduction makes the difference between pro holding or not holding.
The vibration characteristic of early model screamers has been reduced by replacing horizontal rows of bar tacks that popped successively, causing "mini-falls" that set up vibration, with vertical rows of stiching that rip continuously. Gate vibration is still a concern with screamers. For one thing, the screamer is elongating and the bottom carabiner is going for a ride, banging against the rock as it goes. At the very least, the bottom biner should be a wire gate biner, and it is probably best to use a locker.
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hammer_
Mar 4, 2003, 4:59 PM
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Screemers on ice are a definate advantage but on rock? Seems to me that if you think your placement sucks so bad that you need a screemer, either it won't hold in the event of a fall or it will more than likely walk out due to rope drag anyway.
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mountainmonkey
Mar 4, 2003, 5:02 PM
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I have fallen on a screamer on a pin that was just below my feet and I was about 30 feet up. The screamer only activated the first two stitches meaning that I only achieved a load slightly more than 2 kN. The activation force is repeatable to +/- 5% according to Yates. The numbers add up, and using a screamer will increase your chances of a critical piece holding.
useful info:
www.petzl.com
http://www.yatesgear.com/climbing/screamer/index.htm
and specifically
http://www.yatesgear.com/climbing/screamer/use.htm#1
Screamer - reduces peak loads by 3-4 kN (26 kN runner strength)
Shorty - reduces peak loads by 3-4 kN (26 kN runner strength)
Zipper - reduces peak loads by 6-8 kN (26 kN runner strength)
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pywiak
Mar 4, 2003, 5:29 PM
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My previous comment was based on the experience of a real-world field test. Here are some additional details, in response to RGold's speculations.
1. I have no doubt the screamer absorbed fall energy while the bar tacks blew out. The energy absorption capacity of the screamer I used was inadequate in the context of what should've been a 10 footer (i.e. the piece is just below your feet when you fall).
2. In retrospect, I'm almost certain the knob is still there, because the sling failed. The sling failed in the middle of the webbing on the portion that was looped on the knob. The knots in the webbing did not fail. The sling did not look like it was cut, but since this is the only sling I've snapped in use, I don't have much to compare it with.
3. The fall factor if the placement had held would've been low (10'/80' = 0.125), far less than the "average" trad fall factor.
4. In several thousand feet of lead falls over the past 30 years (I'm not as good as I wish I were), this is the only time a piece of the protection system has unclipped itself from the rope. The fall was free, away from the wall, so I'm confident the piece did not unclip from slapping the wall. I strongly believe from the physical evidence that the vibration from the bar tacks releasing (it was an "old-style" screamer) set up the biner gate movement that detached the piece from the rope immediately after the piece separated from the rock. Unfortunately, wire-gate biners that might have prevented this were not marketed until years later.
5. From a subjective perspective, the failure of the screamer and the piece did not alter my trajectory (a slow rotation backwards to a full inverted position, head-first facing out from the wall when the fall terminated), nor did I feel a "tug" as the piece failed. It felt like a free drop all the way.
6. Based upon my experience, I hold the opinion that screamers have extremely limited utility in the context of free-climbing protection systems. If a placement is sufficiently marginal that you feel you need a screamer, don't fall on that piece, or don't expect the piece to hold. You may get lucky, and your results may vary. Also realize that the benefit of a screamer is good for one fall - after that it becomes a junky runner.
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mountainmonkey
Mar 4, 2003, 5:49 PM
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pywiak,
Maybe it would be useful if you were to tell us what brand of load-limiting runners you were using. They don't sound like the new Yates ones. I am curious of the specs (if any are available). I am sorry that you have had such a bad experience with load-limiting runners, but it sounds like the ones you used were of poor quality and the newer ones are much better.
From pywiak:
In reply to: The energy absorption capacity of the screamer I used was inadequate in the context of what should've been a 10 footer (i.e. the piece is just below your feet when you fall). |
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pywiak
Mar 4, 2003, 6:13 PM
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The brand was Yates, they were commercially produced, and the year was 1986. Other than realigning the bar tacks lengthwise rather than crosswise, I've seen no significant design or manufacturing changes in this product.
I'm not saying that this product does not have utility in specific climbing situations. I am saying I've found it to have limited utility in free-climbing protection systems, to the extent that I don't use it for that application. I feel strongly that in free-climbing situations where screamers might be used, it is safest to not fall, or to retreat, or to arrange an alternative and more secure protection system.
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tanner
Mar 4, 2003, 6:28 PM
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This is where I think a screemer would be of use:
A runout muli-pitch slab climb first bolt is 20' of the belay and there is another 20-30' before your next pro. If you fall Your flying 50+ feet onto 1 bolt. If that bolt goes the result would be one crazy factor 2 fall :(
The screamer could be a life saver! Besides you wouldn't want to fall on a route like this anyway you probable wont toast too many screemers.
I think I'll get one for just that reason
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mountainmonkey
Mar 4, 2003, 6:50 PM
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pywaik,
That is interesting that we had pretty different experiences. My fall was a higher fall factor and I only ripped the first two stitches where you had ripped all of them. Maybe it was due to a difference in rope technology (2000/1986). I was on a well used sterling marathon ~9.6 which has a very soft catch. In Eldo, especially on routes where only fixed pins protect cruxes, I often choose to have a screamer or two with me. I fell on Over the Hill at the first (new) pin and I think it would have held with or without the screamer. It did make me feel more confident before I fell (even if the pin popped, a bomber cam was five feet farther down in a relatively clean fall). I also choose not to fall if the pro beneath me is inadequate and the piece blowing would put me onto a ledge, spike, or the hard ground - I would rather retreat, aid, or find adequate pro.
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christianbennet
Mar 4, 2003, 6:50 PM
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all this debate on the pros and cons of screamers, i'm wondering how many people are using gri gris vs atc style, and how much effort is put in on the belayer's part to give a soft/dynamic catch, i've seen many people give short/running belay's even when the climber is way off the deck....
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flamer
Mar 4, 2003, 8:20 PM
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rgold wrote:
You don't need a scream aid for any belayed situation. Scream aids are for aid climbing, obviously, and in particular they are meant to save your butt when you fall (or bounce too hard) on your daisy chain. In this case, there is no "load doubling" effect on the top biner, and you need activation at 1.5 kN to keep a piece from pulling under sudden imposition of body weight.
It is interesting to me that you say this, and I have to ask, Have you ever seen a screamer work? You can spout all the book knowledge you want, It doesn't always apply to the real world.
My statement comes from watching JOHN YATES himself test his screamers in a fairly controlled setting. After which I had an excellent discussion with him about different scenario's. John is the one that told me it would be a good Idea to use an Aid scream and a screamer in sucsession. Can you Honestly say that it wounldn't be better to start limiting the shock load at less than 2Kn? Or are you just trying to make yourself look good by making someone else look bad?
josh
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boltdude
Mar 5, 2003, 1:27 AM
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pywiak,
Bummer about the biner unclipping and the webbing snapping. But that same situation could easily happen with no Screamer involved - biner gates vibrate open in falls all the time (which is why most broken biners show no damage to the gate), and if a sling breaks then a slingshot/rebound effect could be the main cause. Screamers could increase the likelihood of gate vibration, but that may not be the cause of what happened. I always use wiregates on the rope end with Screamers, but I do that with normal draws and slings as well.
There've been a number of big falls on small gear with Screamers where they ripped all the way and the piece held (big one on the FA of Nightmare on California Street on a 0 TCU under a flake). We did some haulbag drops in a pretty realistic situation (180lb bag in the range of 30' fall 120' out from the belay on a 60-70 degree slab) and broke a couple 1/4" bolts without Screamers (one homemade aluminum hanger, one bolt), then in a third test ripped a Screamer fully and the bolt held. In one of the no-Screamers-involved falls, the draw on a bolt 3 below the top one unclipped during the fall for no apparent reason.
I use them all the time but have never fallen on one - but of course, if I'm using one then I'm trying really really hard not to fall...
Greg
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brutusofwyde
Mar 5, 2003, 6:25 AM
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I use screamers on nearly every trad lead, currently own eight, and four scream aids.
Over the past 30+ years I have taken (and held) numerous falls involving screamers and scream-aids, ranging from a few stitches popped to full-blown rippers. These falls usually involved pieces of unknown strength (such as an untested fixed pin on Astroman that stopped a 30+ foot fall, screamer fully blown) pieces in poor placements (cam in a flared groove on the FFA of Planaria that stopped a 10-foot fall -- approx fall factor of 1, screamer approx 50% activated) or small pieces (blue alien that stopped a 15-foot fall on Banzai, Calaveras Dome -- approx fall factor 1, scream aid fully blown, climber stopped 3 feet from the talus)
Gate flutter/vibration was an issue with the old-style "Air Voyagers" which used horizontal bar tacks. It is much less an issue with the current design, nevertheless all leaders should be aware of the potential for inertia-based gate opening (such as when the spine of the carabiner is slapped against the rock) and gate opening caused by the gate scraping against the rock.
In situations where the potential exists for this type of failure, where such a failure would have disastrous consequences, it is still a good idea to use locking carabiners or doubled/reversed carabiners.
In situations where extremely high fall factors are possible, I use two screamers in series.
Every piece of ice pro gets a screamer or ice scream. When I place two ice screws (such as before an unprotectqable crux) I use an ice scream on the higher piece and a standard screamer on the lower piece, resulting in automatic equalization as the screamers activate.
Similarly on rock, (as mentioned in an earlier thread) where the leader wishes to equalize two pieces at approximately the same height, the higher screamer rips until it has extended enough that the lower of the two begins to activate as well: minimal futzing optimizing the protection available.
You will hear many differing opinions on the utility of these tools. Personally, I won't leave the ground without them.
Brutus of Wyde
Old Climbers' Home
Oakland, California
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crotch
Mar 5, 2003, 6:52 AM
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gone
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dangermonkey
Mar 5, 2003, 7:04 AM
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I've never carried a screamer nor has anyone I've climbed with. Come to think of it, I have not seen one at the ice crags niether. Am I missing out on something? or am I just blind. Should a climber carry a screamer?
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rgold
Mar 5, 2003, 11:28 PM
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In reply to: It is interesting to me that you say this, and I have to ask, Have you ever seen a screamer work?
In reply to: You can spout all the book knowledge you want, It doesn't always apply to the real world.
In reply to: My statement comes from watching JOHN YATES himself test his screamers in a fairly controlled setting. After which I had an excellent discussion with him about different scenario's. John is the one that told me it would be a good Idea to use an Aid scream and a screamer in sucsession.
In reply to: Can you Honestly say that it wounldn't be better to start limiting the shock load at less than 2Kn?
No. And I can't honestly say that it wouldn't be better to make a string of ten screamers either. Personally, I don't carry scream aids, and my understanding of the loads involved, as described in my post, suggests to me that if I really needed to use a scream aid chained with a regular screamer, the piece in question is so bad its worthless. However, Brutus of Wyde describes using one in a successful "catch," which constitutes real real world experience. (We don't know, of course, whether or not a regular screamer would have worked just as well, or even whether a screamer was needed at all. This is the trouble with real world experience.)
In reply to: Or are you just trying to make yourself look good by making someone else look bad? |
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flamer
Mar 5, 2003, 11:50 PM
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In reply to: My statement comes from watching JOHN YATES himself test his screamers in a fairly controlled setting. After which I had an excellent discussion with him about different scenario's. John is the one that told me it would be a good Idea to use an Aid scream and a screamer in sucsession.
Guess what! JOHN YATES IS THE MANUFACTURER!!!!
So you've never been in a situation where the only piece you could get was a complete piece of crap? Guess what putting a scream Aid and a standard screamer on it will increase the chances it will hold. Also as, Brutus stated, when in situation where high fall factor's can be present putting standard screamers in a "chain" is a good idea( that obviously isn't an exact quote-sorry if I misrepresented your statement Brutus).
You are correct in that I don't know what your intentions were/are. You should know I could care less! However there is a difference between disagreeing, and blatantly telling people I am wrong. When, in fact it is a matter of opinion. And my statement is an educated one, having come directly from the manufacturer.
josh
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apollodorus
Mar 6, 2003, 12:59 AM
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Scream-Aids look like Screamers, but they open up at about 350 lbs, or something.
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rgold
Mar 6, 2003, 3:45 AM
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In reply to: Guess what! JOHN YATES IS THE MANUFACTURER!!!!.
Well of course I know that, it was my point. You're so intent on having a fight you don't even recognize when a person is willing to concede something, although I'm puzzled why Yates would say what you claim. What he says on his web site is
SCREAM AIDS: Activation:>1.5kN. Reduction in system peak loading 1.5-2kN. Runner Strength: 7kN. "use on extremely marginal aid placements only" (emphasis is his).
In reply to: Guess what putting a scream Aid and a standard screamer on it will increase the chances it will hold.
Well, maybe. The trouble is, since scream-aids were designed for aid placements, the entire runner tests at 7 kN. Everything else in the belay chain tests at around 25 kN, so you are putting a weak link (very weak compared to the other components) in the chain (which of course is fine in the intended use situation).
So just maybe the scream-aid will make a difference by activating at .5 kN lower load, although I have already argued why I doubt it, but you are also in the paradoxical situation that if your manky piece turns out to be better than you thought, you've constructed a weak belay chain that could fail. If high fall factors are present, chaining screamers may be a good idea, but chaining a scream-aid means you've reduced the holding power of your system to below gate open level of most carabiners in order to gain a half-newton activation threshold.
This does not strike me as a good idea, but as you say, it is a matter of opinion, neither of us seems to have said anything that convinces the other, and so I, for one, am done with this topic.
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