Do Screamers Work?

Eric Moss wrote:Just rig multiple screamers in parallel, so their total activation force is just less than the lowest estimated strength of the piece.

When i am traditionnaly climbing, I make sure I always have my trusty guessthekilonewtonometer with me to precisely evaluate the strength of my wobbly pieces.

It allows me to determine the exact number of strands I must remove from my slings so it fails at the desired time!

I agree, removing the nylon strands one by one at a stance is slightly strenuous but SO WORTH IT!

... you are overthinking it!

Jim Amidon wrote:All I know is my buddy took a 60' lead fall in Ouray on one, it tore all the way and his screw held.......... All caught on video, believe or not all the tests, but well, he's still walking, a little shaky, but is fine and the point is his screw held.

Hey Jim, Can we see this video? I know your posted along time ago when this thread started but I just saw it and would love to see a 60 footer onto a screw.

John The Wolf wrote: When i am traditionnaly climbing, I make sure I always have my trusty guessthekilonewtonometer with me to precisely evaluate the strength of my wobbly pieces. It allows me to determine the exact number of strands I must remove from my slings so it fails at the desired time! I agree, removing the nylon strands one by one at a stance is slightly strenuous but SO WORTH IT! ... you are overthinking it!

I'm not talking about removing nylon strands, I'm talking about using screamers in parallel, so they will have the most benefit. Is it really that hard to guess, for example, that a piece will hold more than 4 KN?

Eric Moss wrote:Is it really that hard to guess, for example, that a piece will hold more than 4 KN?

No leader with even a minimal amount of experience makes these kind of quantitative assessments. And yes, it is hard to guess the kN a piece will hold, simply because of the number of dependent variables.

As Stich asked (either here or in one of your other threads) - do you even climb?

Marc801 wrote: No leader with even a minimal amount of experience makes these kind of quantitative assessments. And yes, it is hard to guess the kN a piece will hold, simply because of the number of dependent variables. As Stich asked (either here or in one of your other threads) - do you even climb?

What kind of leader does not know if his piece should hold more than 4 KN?

I mean, sure some are on the borderline, but others are very obvious, and those can obviously be given two screamers.

Yes, I do climb. Do you?

Eric Moss wrote: What kind of leader does not know if his piece should hold more than 4 KN?

Cams rated at minimum 7kN in a parallel sided crack, relatively closely spaced, on a 5.12:

youtube.com/watch?v=GQ854rw…

Screamers in parallel is a waste of gear... While great in theory the deployment forces, having both go together, etc. gets tricky as soon as they're not truly parallel... Like in a rounded cam thumb loop, or biners are stacked by a sling pinching, etc.

If you're really worried about a piece, use a screamer. If you're at the point where you're thinking parallel screamers, you're probably at the point where you don't need a screamer at all. If you're really that iffy about it, place and equalize another piece of gear. Or climb with half ropes (lower impact forces). Or stick to nice bolted sport routes.

This thread is like a bad monster movie villain.

JK- wrote:Screamers in parallel is a waste of gear... While great in theory the deployment forces, having both go together, etc. gets tricky as soon as they're not truly parallel... Like in a rounded cam thumb loop, or biners are stacked by a sling pinching, etc. If you're really worried about a piece, use a screamer. If you're at the point where you're thinking parallel screamers, you're probably at the point where you don't need a screamer at all. If you're really that iffy about it, place and equalize another piece of gear. Or climb with half ropes (lower impact forces). Or stick to nice bolted sport routes.

But the OP and the CAI tests seem to suggest otherwise, hence the long thread. Maybe two aid screamers, for a 3 KN activation energy would be better. At this point, I'm just reinventing the screamer, but maybe it needs reinventing since there are apparently problems with it.

Another idea:. What about Purcells to protect pieces?

dirtbaglawyer.wordpress.com…

Marc801 wrote: No leader with even a minimal amount of experience makes these kind of quantitative assessments. And yes, it is hard to guess the kN a piece will hold, simply because of the number of dependent variables. As Stich asked (either here or in one of your other threads) - do you even climb?

Depends on rock quality. On good rock I (mostly) trust my pieces to hold their rated value. I say mostly because I like to have a couple pieces between me and the ground.

Marc801 wrote: Cams rated at minimum 7kN in a parallel sided crack, relatively closely spaced, on a 5.12:

Indian creek sandstone AND using cams with significantly lower holding power.... Metolius is going to give you 20% more outward pressure than an alien. Can't say what caused it by it is a bad idea to be using aliens in places they aren't suited to.

That IC video is known to be climbers climbing too soon after rain storm. Wet, weak rock contributed.

Go attach a ascender onto a rope and jump with and with a screamer attached with the same distance

This logic was made to create Petzl's Absorbica and having done a large number of falls on this to test rope damage, they do help in that situation.

The extra falling distance doesn't exceed the amount of pressure absorbed. So while it may not be a huge difference and eliminate the piece from falling, it reduces it and like everything else doesn't guarantee your safety.

patto wrote:Indian creek sandstone AND using cams with significantly lower holding power.... Metolius is going to give you 20% more outward pressure than an alien. Can't say what caused it by it is a bad idea to be using aliens in places they aren't suited to.

mattm wrote:That IC video is known to be climbers climbing too soon after rain storm. Wet, weak rock contributed.

Exactly my point. Our new favorite troll asserted that any competent leader could look at a piece and assess that it can or cannot hold 4kN and ignored all of the other variables that come into play.

Marc801 wrote: Exactly my point. Our new favorite troll asserted that any competent leader could look at a piece and assess that it can or cannot hold 4kN and ignored all of the other variables that come into play.

You missed my point entirely. If you increase the activation energy, you can make the screamer more effective in at least some cases because it won't counteract a dynamic belay as much. Does that make sense to you?

All I know is a wire hanger on a rivet clipped with a screamer held a 30-40 foot ripper I took on El Cap.

Scott O wrote:All I know is a wire hanger on a rivet clipped with a screamer held a 30-40 foot ripper I took on El Cap.

I took a 20 footer on a C3 000 with only two lobes engaged. Doesn't prove a thing until you know the whole story.

edit to add: Without a screamer

Scott O wrote:All I know is a wire hanger on a rivet clipped with a screamer held a 30-40 foot ripper I took on El Cap.

Stuff like this and the other story about a 60 footer on an ice screw help perpetuate the rumor that screamers work. Unless you went back up and took the same fall without a screamer, and it pulled, you really have no idea.

I think of the mank I've fallen on without screamers. My mind would probably attribute it holding to a screamer had I used one. That's human nature. It doesn't make you correct.

If you're truly concerned about gear ripping, shop around for a lower impact rope. I want to say doubles are about the lowest impact if the second rope gets partially weighted before the top one totally arrests the fall. There are also plenty of lower impact single ropes out there. This is a proven method for lowering impact forces, not relying on an incomplete understanding of causation vs correlation to stop your fall.

It was always my impression that we stay safe by creating a network of gear below us, not relying on any single piece.

Why did this topic return from the grave?

Its probably worth noting that in a practical, rather than theoretical situation, if you are placing a screamer its because you have a really small/ really shitty piece of gear, and are hoping not to test it- Mental Pro. Maybe the psychologists should weigh in rather than just the physicists and engineers.

Kyle Tarry wrote: Huh? What are you talking about? What does "counteract a dynamic belay" mean? When treated like a single rope, half ropes appear to have approximately the same impact force as a single would have: willgadd.com/single-and-hal…

On point 1. I think this is about the screamer absorbing energy that would have been absorbed by the rope/movement of belayer anyhow. So taken as a system, the screamer might add little benefit. This possibly lies at the heart of why manufactures have found it difficult to show screamers work in realistic situations.

On 2. Will makes the point "1. Half ropes likely do not offer significantly lower impact forces than single ropes in high fall-factor falls where one strand is clipped as is common." The tests were in high factor fall where the rope was stretched out. Ever top roped on an 8mm? Falling off is like stepping off onto elastic. Nice and gentle. The question is what are the forces like for a more normal FF=0.1 - 0.3 fall. It would be good to see this data.

Kyle Tarry wrote: Huh? What are you talking about? If you're alternating gear on your ropes, it's unlikely that you're going to significantly weight the second rope during a fall. I just sketched out a quick scenario with a fall 50 feet up and the gear 5 feet apart, and it doesn't seem likely that you'll hit the second rope.

This is really interesting to Brit climbers, as most of the time they use double ropes. Almost all the time the second rope goes tight (you can see this as the belayer or as the falling climber), but the question is, how much force is on that lower piece on the other rope?

The static elongation with be about 7%. In a reasonable fall, 15%. So with 50ft of rope out and 5ft to the lower piece, some force will hit the second piece. But I really don't know how much.

The great thing about double ropes for this however is that the lower piece is unperturbed by the rope to the upper piece. Take a look at many a US weekend wipper type video. The lower piece gets pulled all over the place, then when the upper piece fails, the lower piece is not best orientated. Double ropes solves this.