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Posted

In the past, I have known a couple people who insisted on it. I never had the facts to back up why not to use them.

Talking to John Yates today about another topic, I asked him about it and he gave me the history on why people started doing it and why you don't.

Just thought I would share.

jedi

Posted (edited)

screamers suck. once they rip, they shock load the piece, hence the chance of it ripping is bigger. ropes absorb more and specially the skinny half ropes. black diamond did a lot of testing and they decided not to make screamers for the mentioned reasons.sreamers are just another climbing myth, just like placing screws 10 degrees up. for decades every book was presenting screws to go up and guess what? in good ice 10 degrees down holds much more force.

so putting lockers on the screamers is one of the most retardo thing i have heard in a long time

Edited by glassgowkiss
Posted

I dunno Bob. People have done extensive testing, lab testing as well as in true climbing situations (eg falling on a screamer in the gym and measuring the impact force on the pro). Results show they do work as far as reducing the impact on the pro.

 

A screamer cannot shock load the pro more than if there were no screamer at all. Physically impossible. You could argue that the vibration of a ripping screamer could vibrate a gate open and drastically weaken a biner, but that's the only sensible argument against them.

Posted

but that's the only sensible argument against them.

 

.. maybe not. There's also the consideration of the additioanl legnth of the screamer, which is what - 24" / 36" ? May not seem like much, but I've seen a leader fall on his first screw placement (with a plain qd) and be caught by the rope only a few inches above the deck. If he had a screamer he would've hit the ground for sure.

 

Since then I usually use a plain old quickdraw on my first screw to prevent the extention, then it's screamears till I run out of em.

Posted
but that's the only sensible argument against them.

 

.. maybe not. There's also the consideration of the additioanl legnth of the screamer, which is what - 24" / 36" ? May not seem like much, but I've seen a leader fall on his first screw placement (with a plain qd) and be caught by the rope only a few inches above the deck. If he had a screamer he would've hit the ground for sure.

 

Since then I usually use a plain old quickdraw on my first screw to prevent the extention, then it's screamears till I run out of em.

You mean the fall on Icy BC that you told me about? Good point. Then again, the guy is lucky he didn't have a stretchier rope, or a looser knot, or.... I'll amend my statement and say that IN GENERAL, screamers are a good idea. Either way, Bob is wrong. smirk.gif

 

Screamer battlecage! boxing_smiley.gif

 

pitty.gifwave.gif

Posted

Looking at one of mine now .. a yates regular screamer will extend 10", going from 8" to 18". A yates "zipper" has double the number of folds going from 8" to 28".

 

Not much I know, but last year I saw someone take a lead fall on icy bc, falling on his first screw as he was trying to place his second, the rope caught him about 6" off the deck (he badly torqued an ankle on the way down).

 

Likely to happen often? No probably not, but I do think about it. Of course we're not supposed to fall on ice anyway right?

Posted
.. maybe not. There's also the consideration of the additioanl legnth of the screamer, which is what - 24" / 36" ? May not seem like much, but I've seen a leader fall on his first screw placement (with a plain qd) and be caught by the rope only a few inches above the deck.

I'd want the first piece of pro to have a screamer - it'll probably have the highest fall factor of the entire pitch.

Posted

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.

Posted

I have and still do on a of mine. There are lots of "ideas" out there about what they do and don't do - I'll fire off some of my thoughts.

 

They're most useful where high fall factors will be present - ie first few placements on a pitch - the higher you go the more the ropes dynamic capabilities take over.

 

Worrying about extension is a valid argument IF the decking potential is there - obviously if it's that close - an Actual thought based judgment call will have to be made - thinking for yourself is fun!

 

I use lockers on a few of mine - not so much because of vibration but for the fact that usually - i'm placing these early on the pitch and/or on gear that's not great or not abundant. These two things really make me want my rope to REMAIN clipped into the piece - as unlikely as that may be, a wipper on slab with one bolt between you on the ground really makes me want keep in clipped

 

The idea of the screamer isn't to absorb force (ie eliminate energy) it's to distribute said energy's impact over a greater area (time) thus keeping the PEAK force lower.

 

Summary - I place screamers on pieces early in a pitch that I want to keep peak forces lower on. I use lockers when said piece is my sole pro at that point and thus important to remain attached to.

Posted

I've heard threads about screamers come up a few times now, so this time I decided to put on the nerd hat and way in... This is all physics textbook aiding, I've never had any first hand experience with screamers aside from fondling them in the gear shop. Let's say two climbers that weight the same amount take the same fall, one on a screamer, one on a standard draw. Because they fall the same length, when they hit the anchor their momentum is the same, that is the massXvelocity is identical. They both stop, so both of their change in momentum is the same. The change in momentum(dP) or their IMPULSE, is the same. Impulse is also defined as the area under the curve of a time-force relationship. Because the area is the same, but the time is longer for the screamer, the max force on that chart is gonna be a lot lower. So assuming if the sketchy anchor has a low maximum force, the screamer is a plus. Now as for the arguement that the anchor will be shockloaded when the screamer is full extended, I think Matt was on to something when he said thinking for yourself is fun. Which is going to lengthen the time for the force to be absorbed more, the stretch of the rope or the expansion of the screamer? When you're lower on a pitch (higher fall factors) you're not going to get much rope stretch, so the screamer will help you. At what point do you think the rope strectch will be longer than the force on the screamer? Again, a judgement call, but obviously the more rope you have out, the more stretch (lower fall factor). As for increasing your risk of decking, like matt said, thinking is fun, but I hope I'm never in a fall where 10'' will make the difference between decking and no. As for me, I buy into the arguement that screamers have their place, but you have to think about it. Ok, nerd hat off, feel free to pick apart. Any physics-smart types out their wanna tell me how this sounds?

Posted

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.

Posted

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.

Posted
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.

 

The point of the Screamer is that it only limits the force until it fully extends so Im not surprised by these findings yellaf.gif I have only seen one Screamer fall, it was in shitty wet ice, and only about 1/3 of the stitching ripped from a 12 foot fall. wazzup.gif I have 5 screamers and will continue to use them.

Posted
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. Geek_em8.gif I'm waiting for the invention of the massless gate biners. pitty.gif

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