Does anyone still use locking binners on Screamers

[iain]

Post the link, please, if there is one.

There is no link, but it most likely could be found in past ITRS proceedings if you really want to find it, thought it might be proprietary data for RfR or something

[iain]

I was not suggesting they don't work, I was just pointing to some info about tests that were done on them.

[cj001f]

Rigging for Rescue did some destructive testing on Yates screamers. During the drop the force was delayed, but once the screamer was fully-extended, the force went right back up to what it was w/o the screamer in place.

Screamers absorb energy in the system - the energy after the screamer has burst HAS to be lower than it was before.

[Dru]

force is not energy physics class!

[dylan_taylor]

So who uses these things rock climbing?

 

I've got a mess of 'em and bring them ice climbing every time. But not once have I used them for straight up rock climbing. Alpine once or twice but not usually.

 

I use them all the time for rock climbing. I weigh about 200 Lbs and I climb a bit in Eldo, so I place lots of little RP's, and I clip lots of antique fixed relics. I also climb in the desert and Black Canyon a bit, and I use them a lot there when clipping dodgy sandy funk or RP's in rotten pegmatite. Two short screamers is usually all I carry, and I either use them when clipping mank close to the belay or clipping RP nests anywhere else. It is true that the fall factor tends to be higher close to the anchor, but fall factors can also be disturbingly high on long stretcher pitches with lots of rope drag. Less rope is available to catch the fall, so it may be nice to have something else in the system to extend the period of time that fall energy is being accomodated.

 

I never would have imagined screamers would become such a "controversial" topic. Obviously, they are specialized pieces of equipment that only come in handy in certain situations, but if you have them in those situations - you're psyched! They work. I watched one save a friends ass in squamish a couple of years ago.

[fern]

controversial???

 

the "where do I clip my belay biner" thread went 4 pages! Sit back friend, this debate hasn't even gotten started

 

 

[Stephen_Ramsey]

Rigging for Rescue did some destructive testing on Yates screamers. During the drop the force was delayed, but once the screamer was fully-extended, the force went right back up to what it was w/o the screamer in place. Use 'em if it makes you feel good I guess.

This is totally expected and not surprising, and doesn't (to my eyes) mean that Screamers are not useful. The screamer will dissipate a calculable, well-defined amount of energy out of the system (basically the activation force times the length of the screamer). It is the kinetic energy of the falling climber that is (indirectly) being dissipated as the screamer rips. From mechanics, we know that kinetic energy is related to the square of the velocity of the falling climber (KE = (1/2) m v^2). So after the screamer fully rips, you are not falling as fast as you would otherwise. This means that the subsequent impact on the protection is going to be less severe than it would in the absence of the screamer. Simply put, it is as if you free-fell for less distance than you really did. How much less? Well, it is a distance roughly equal to the energy dissipated by the screamer, divided by your weight in newtons.

 

The relevant quantity to study is the MAXIMUM tension in the rope achieved during the fall subsequent to the screamer ripping, not the tension in the rope at the moment the last stitch rips on the screamer. These are two totally different things, because in the worst case, the climber has nonzero kinetic energy and continues to fall after the screamer has fully ripped. So the rope plus harness continue to stretch, and the forces in the system continue to increase until the climber has almost decelerated to zero velocity, at which point the forces will rapidly decrease. It is this maximum force that matters. And from Yates' literature, it appears to be the case that this maximum force is indeed smaller if you used a screamer to dissipate energy from the falling climber.

 

Not trying to convince you that screamers are great or anything, just trying to clarify what might be a potential flaw in the interpretation of this study's results.

 

Cheers,

Steve Ramsey

Edited March 4, 2004 by Stephen_Ramsey

[iain]

There must be an epidemic of malfunctioning popcorn makers out there because every photo I see of popcorn involves a huge bucket that has overflowed onto the table

[dylan_taylor]

controversial???

 

the "where do I clip my belay biner" thread went 4 pages! Sit back friend, this debate hasn't even gotten started

 

 

 

I have my popcorn and soda pop now.

 

Stephen, thank you for the useful and informative explanation. I remain a believer. I don't know where P-Bob ever got off on claiming that screamers and 10 degree upward angles are "myths". The evidence seems rather empirical to me.

[Stephen_Ramsey]

the gate vibration issue is why some ppl used to use lockers on them but since wiregates dont have gate flutter issues, it become irrelevant.

But wire gates DO have flutter issues...just greatly reduced compared to normal biners. I'm waiting for the invention of the massless gate biners.

But from particle physics, we know that neutrinos *are* massless! (OK, this is a lame joke).

[cracked]

[Dru]

ya, cause they found out the neutrino DOES have mass just recently thats why the solar neutrino imbalance occurs

[iain]

[skykilo]

*Geeky Physics Post Alert*

 

Well, to put it precisely, we know there is a non-zero mass difference between different types of neutrinos, and so they can't all be massless.

 

There are three types of neutrinos in the Standard Model of particle physics, but we already know it's wrong because it only allows massless neutrinos. A fourth neutrino might help with certain aspects of solar models.

 

Sorry, it's an involuntary reflex.

[Dru]

there is nothin easier than trolling for physics geeks

[Jedi]

I have just had people tell me in the past that you need to have a locker on the bottom of every Screamer. Therory being that the opening of the screamer might open the gate of a biner by "gate vibration". I have not used lockers on the bottom of Screamers before.

Yates described to me how his stitching rips which does not cause "gate vibration" in binners. But he recommended wire gates in the event the binner smacks ice or rock which can cause a non wire gate to open (wire gates are less suseptible as most people know). BUT the Screamer would reduce the force enough that it would not break a binner with the gate open anyway.

He mentioned something about John Bouchard and a broken binner. I guess it happened 15 or 20 years ago. That incident is what started people using locking binners on Screamers. Much has changed since then with gear enovations but some people still like the idea of lockers on there screamers. But it is no longer neccessary according to Yates.

 

The way I see it, John as been designing and testing gear for MANY years. He has probably heard a lot of constructive critisim from people who have "tested" his absorbers personally. He has probably tested most of the theroies post here. He would know.

In a world where people sue one another for anything, John was pretty confident telling me (someone he does not know) that his product works safely without a locker on the bottom binner. If there was anyone here that was taking the time to deal with a locker in a sketchy situation, now they have piece of mind they don't need a locker if they thought might. That was my point in posting this info.

That's all I need, just thought I would share. Take it or leave it.

[Dru]

1) never trust a gear manufacturer to do anything other than tell you you need the gear they make

 

2) biner = carabiner

binner = guy who goes thru the garbage for cans and bottles

 

[Jedi]

Yeah Dru, I always keep that in the back on my mind manufacturers.

Point is, he is not selling me Yates wire gates. He probably does not care if I use a locker or a wire gate on his absorber. There is no advantage using a locker on a absorber over a non-locker.

 

In this case, I do believe John knows more than anyone here about absorbers. I am amazed at the number of physics professors and engineers we have on the board

 

Dru, as you probably have noticed, my spelling is bad. Even with spell check

It's because I'm a binner, anyone have any kans or bootles

[colt45]

For actual data (which is occasionally a good way to figure things out) check out this website:

 

http://www.yatesgear.com/climbing/screamer/use.htm

 

While it is not explicitly stated on the webpage, it is probably safe to assume that the numbers in the table were determined from drop testing.

 

a specific example of interest:

fall factor: 1.4

anchor force: 14 kN

with Screamer: 11 kN

with Zipper Screamer: 8 kN

 

In this example, a gate-open carabiner will break even with a Screamer. with a Zipper, it may or may not break depending on the specific brand of carabiner. Interestingly, even a #13 stopper would break with a screamer in this case (strength 10 kN). The testing probably uses a totally static belay.

 

Example #2

Fall factor: 0.5

Anchor force: 8 kN

With Screamer: 5 kN

With Zipper Screamer: 2 kN

 

So without a screamer a #5 stopper (strength 6 kN) would break. With a screamer it would hold. With a zipper even a #1 stopper (strength 2 kN) may hold (although it takes close to 2 kN of force for the zipper to activate in the first place).

 

Based on these numbers, Screamers would be critical pieces of gear in specific situations.

 

The gate flutter issue could certainly be determined experimentally (eg do drop tests with a high-speed camera to see what happens to the bottom biner). Although it does seem like a wiregate would do the trick...?

[Dru]

basically the point is, i don't know anyone who ever used locking gates on screamers EVEN THOUGH at one time it was recommended. Just like I don't know of many people who make sure the bottom clip on the sport route they are trying, has locking biners on it.

 

These technical gear warnings always crack me up. See latest R&I where some guide is recommending not tying off the cordelette but instead using a sliding-X set up.

[layton]

I'd like to see a link from a company where screamers aren't their major source of revenue.

Polish Bob,

Why don't you back up your stupid fucking claims and cite some sources you miserable clownpuching high-water sheep shagger!

[Jedi]

Come on Dru. You are a "locker". Word on the street is you "lock" when ever you can. Some of the boys at the laundry mat were telling me about your locking binner obsession. You even have locker on your key chain. I saw it the other day when I was binnering in my favorite dumpster.

 

Dru-Locker is what they call ya in the hood, isn't? Just admitt it

[snoboy]

I'd like to see a link from a company where screamers aren't their major source of revenue.

 

I would bet that between the high QC reject rate, the large amount of work, and the low volume, they really aren't that profitable.

[max]

I would bet that between the high QC reject rate, the large amount of work, and the low volume, they really aren't that profitable.

 

 

BD: "Yeah, we're dedicated to the people. Liie, we're all a bunch of climbers. We don't make screamers 'cause they don't work *cough*bullshit!*cough*. Did I mentio nwe don't care about profit? We're to community oriented to care about profits."

 

I'm all about companies being profit grubbing mother fuckers. I am. There's no other was it can happen in capitalism (without regulation, and that's even worse than mother fuckers). What pisses me off though is when they start acting cool. "Community" "Partners" "dedication to quality". Quality my ass. More like price point and market niche. And As I said, that doesn't bother me, just don't act otherwise. (I guess its just capitalism kicking it up a notch in pursuit of profits.)

[dylan_taylor]

I'd like to see a link from a company where screamers aren't their major source of revenue.

Here's a link .

 

Mike, did you go to J-tree?