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gunkiemike
Jan 4, 2009, 11:43 PM
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salamanizer wrote: Lazlo wrote: Valid concerns... but not so serious as to prevent its use, right? What's the worst that could happen? You'd just fall the length you would anyway without it. Not a great idea IMO> If you shock load a prissik they can and have melted right through the rope. So the worst that could happen is you fall to your death.
Glaze the rope sheath maybe. Or burn through the 6 mil cord, I could see that as well. But burn all the way through the climbing rope? You're not gonna get me to believe that. At high loads, a prusik knot slips. Which means it moves along the rope to a different spot. The heat is not localized at one place on the rope.
Or do you wrap wired Stoppers around the rope as the prusik?
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tradrenn
Jan 5, 2009, 3:21 AM
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Lazlo wrote: 16stfd16 wrote: I like that idea, but would an auto block be easier to move down the rope while down climbing than a prussick? It would be easier...but for that same reason; it won't grab in a fall.
It can also be done with Shunt or a GriGri.
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Lazlo
Jan 5, 2009, 3:33 AM
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tradrenn wrote: Lazlo wrote: 16stfd16 wrote: I like that idea, but would an auto block be easier to move down the rope while down climbing than a prussick? It would be easier...but for that same reason; it won't grab in a fall. It can also be done with Shunt or a GriGri.
I don't see the Grigri working for this application. Certainly the Shunt...but not the Grigri. Gibbs would be perfect, too.
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tradrenn
Jan 5, 2009, 3:55 AM
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Lazlo wrote: tradrenn wrote: Lazlo wrote: 16stfd16 wrote: I like that idea, but would an auto block be easier to move down the rope while down climbing than a prussick? It would be easier...but for that same reason; it won't grab in a fall. It can also be done with Shunt or a GriGri. I don't see the Grigri working for this application. Certainly the Shunt...but not the Grigri. Gibbs would be perfect, too.
The GriGri way was covered on here few years ago and it is one of the ways that might work if the GriGri locks off, I would personally prefer to do it with a Shunt.
To be honest with you I think this is a bit ridiculous subject to be discussed.
Since I started climbing, I never had to bail using "the above way" .
(This post was edited by tradrenn on Jan 5, 2009, 3:58 AM)
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irregularpanda
Jan 5, 2009, 4:08 AM
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markguycan wrote: Here's another pic of Beckey's 38yr old bolts:[image] http://www.rockclimbing.com/images/photos/assets/8/406788-largest_IMG_0539_small.JPG[/image] http://www.rockclimbing.com/photos/Gear/Bomber__104515.html
Fred Beckey, fuck...
That guy used to climb off of homemade wooden chocks.
Red Bull is made from Fred Beckey's urine.
Fred Beckey is such a climbing bum, he hasn't used toilet paper for 15 years.
Fred Beckey once sold his soul to the devil in exchange for brass balls.
Fred Beckey makes love like an eagle falling out of the sky.
He killed his sensei in a dual and he never said why.
Fred Beckey also....um....fucks the shit out of bears.
Seriously though, Fred Beckey is a savage mountain bum, and has seen more summits than any of us ever will. Maybe I shouldn't go drunk typing any-more.
Innyhoo, more chuck no----- I mean fred beckey jokes.
One time they made a Fred Beckey toilet paper, but it wouldn't take shit from nobody.
There's no reason to go to mars, Fred Beckey has already climbed the mountains there.
Fred Beckey's tears cure cancer.
Too bad he's never cried.
Fred Beckey doesn't sleep, he waits.
The chief export of Fred Beckey is Alpinism.
Fred Beckey can slam revolving doors.
fred Beckey doesn't read books, he stares them down until he gets the information he wants.
Fred Beckey once ate three 72 oz. steaks in one hour. He spent the first 45 minutes having sex with his waitress.
Fred Beckey isn't funny, stop laughing.
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Lazlo
Jan 5, 2009, 4:16 AM
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tradrenn wrote: Lazlo wrote: tradrenn wrote: Lazlo wrote: 16stfd16 wrote: I like that idea, but would an auto block be easier to move down the rope while down climbing than a prussick? It would be easier...but for that same reason; it won't grab in a fall. It can also be done with Shunt or a GriGri. I don't see the Grigri working for this application. Certainly the Shunt...but not the Grigri. Gibbs would be perfect, too. The GriGri way was covered on here few years ago and it is one of the ways that might work if the GriGri locks off, I would personally prefer to do it with a Shunt. To be honest with you I think this is a bit ridiculous subject to be discussed. Since I started climbing, I never had to bail using "the above way" .
I did. Second pitch of a climb...bailed off a detatched pillar.
The technique also works for a questionable belayer.
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tradrenn
Jan 5, 2009, 4:51 AM
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Lazlo wrote: tradrenn wrote: Lazlo wrote: tradrenn wrote: Lazlo wrote: 16stfd16 wrote: I like that idea, but would an auto block be easier to move down the rope while down climbing than a prussick? It would be easier...but for that same reason; it won't grab in a fall. It can also be done with Shunt or a GriGri. I don't see the Grigri working for this application. Certainly the Shunt...but not the Grigri. Gibbs would be perfect, too. The GriGri way was covered on here few years ago and it is one of the ways that might work if the GriGri locks off, I would personally prefer to do it with a Shunt. To be honest with you I think this is a bit ridiculous subject to be discussed. Since I started climbing, I never had to bail using "the above way" . I did. Second pitch of a climb...bailed off a detatched pillar. The technique also works for a questionable belayer.
Excellent point.
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markguycan
Jan 5, 2009, 5:23 AM
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In reply to: I recall a thread on here a while back depicting a piece of pro that consisted of a tuna fish can slung with cord jammed in a crack. I'd clip into it...
(This post was edited by markguycan on Jan 5, 2009, 5:25 AM)
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markguycan
Dec 15, 2011, 10:23 PM
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....a few of my recent hesitant clips.
this is why trad climbing is safer than bolt clipping; at least you know how good your gear is.
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robdotcalm
Dec 15, 2011, 11:16 PM
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tradrenn wrote: To be honest with you I think this is a bit ridiculous subject to be discussed. Since I started climbing, I never had to bail using "the above way" [i.e., using two ropes].
I have a couple of times. Once I was about 10' from the top of a 70' pitch at the crux when a lightening storm blew in. Getting down fast was a necessity. My top piece was questionable. Having double ropes made the downclimbing much safer.
Cheers,
Rob.calm
(This post was edited by robdotcalm on Dec 15, 2011, 11:19 PM)
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mattm
Dec 16, 2011, 4:02 AM
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joeforte wrote: salamanizer wrote: Lazlo wrote: salamanizer wrote: Clip it and go or bail. Bail on the manky goodness? Yes, clip it and downclimb to the last good piece. Wow that would make for a LONG fall if you were to slip and rip the mank. I carry a screamer with a DMM revolver on the rope end for clipping mank. Climb on, treating it like there was no pro at all. I tend to climb well when there's little/no pro. I think everyone has that instinct, but some people are less likely to intentionally climb into those situations.
Loose the Revolver. The lower friction of the pulley mechanism will result in increased forces on the piece clipped if you did fall.
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j_ung
Dec 16, 2011, 11:38 AM
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mattm wrote: joeforte wrote: salamanizer wrote: Lazlo wrote: salamanizer wrote: Clip it and go or bail. Bail on the manky goodness? Yes, clip it and downclimb to the last good piece. Wow that would make for a LONG fall if you were to slip and rip the mank. I carry a screamer with a DMM revolver on the rope end for clipping mank. Climb on, treating it like there was no pro at all. I tend to climb well when there's little/no pro. I think everyone has that instinct, but some people are less likely to intentionally climb into those situations. Loose the Revolver. The lower friction of the pulley mechanism will result in increased forces on the piece clipped if you did fall.
You might be mistaken about that.
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mattm
Dec 16, 2011, 2:33 PM
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j_ung wrote: mattm wrote: joeforte wrote: salamanizer wrote: Lazlo wrote: salamanizer wrote: Clip it and go or bail. Bail on the manky goodness? Yes, clip it and downclimb to the last good piece. Wow that would make for a LONG fall if you were to slip and rip the mank. I carry a screamer with a DMM revolver on the rope end for clipping mank. Climb on, treating it like there was no pro at all. I tend to climb well when there's little/no pro. I think everyone has that instinct, but some people are less likely to intentionally climb into those situations. Loose the Revolver. The lower friction of the pulley mechanism will result in increased forces on the piece clipped if you did fall. You might be mistaken about that.
It's not a simple answer and there really hasn't been much testing on it (that I'm aware of, things may have changed since last I looked).
This thread has the relevant info:
http://www.supertopo.com/....php?topic_id=859036
It looks like in short falls in might help (though it puts more force onto your belayer so they need to be aware of this) and in larger falls it (pulley) INCREASES the force on the top anchor.
Again, the differences can probably be made up for with good belaying...
I like the Revolver but for drag reduction only. You need to be mindful of where in your system you implement it...
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joeforte
Dec 16, 2011, 9:31 PM
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The revolver reduces the friction of the top piece, allowing the entire length of the rope to take the impact. A falling climber has the same kinetic energy regardless of what 'biner is catching him. The revolver just allows more of that force to be dissipated by the belayers side of the rope.
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mattm
Dec 16, 2011, 10:14 PM
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joeforte wrote: The revolver reduces the friction of the top piece, allowing the entire length of the rope to take the impact. A falling climber has the same kinetic energy regardless of what 'biner is catching him. The revolver just allows more of that force to be dissipated by the belayers side of the rope.
Read that Supertopo thread. It's not as straight forward as you'd think. With so many variables, we're probably just blowing hot air without empirical evidence through drop tests and load cells. (Calling Jim Titt or Sterling Jim...)
The question is, does including more rope in the energy absorption system outweigh the increase in the pulley effect?
One of the benefits of the Revolver would be on LOWER pieces. By reducing friction from rope drag on lower pieces the revolver helps to include more rope in the system. I'm all for that. (See Beal's site on impact forces, GriGri's etc. They have a good diagram of how multiple rope bends increase loads on the top anchor.)
http://bealplanet.com/...s/facteurdechute.php
Without testing multiple scenarios, you can't say the Revolver universally reduces the load on the top piece. It likely does IN SOME CASES but is probably detrimental in others.
There are also down sides to having that force transferred over to the belayer side of the rope. It's why I AVOID placing a revolver on the first few placements.
I suspect using a screamer and low impact force ropes will do more to keep peak forces lower than throwing a Revolver on there.
People just need to be aware that there's more at play here than basic physics and there are downsides to a revolver being in place in some circumstances. Until there's testing, we're just participating in conjecture.
I use Revolvers, just not on my "dicey piece" screamers.
(This post was edited by mattm on Dec 16, 2011, 10:23 PM)
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bearbreeder
Dec 16, 2011, 10:50 PM
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interesting ...
lets take the worst case scenario ... no friction on the top piece ... does it increase or reduce the force on that piece ... i think most would agree that the force would be very high ... the test of course is fairly simple .. simply clove yrself into a piece and throw yrself off ... if u dare 
so as friction is reduced, i suspect well tend to see a bit less force on the last piece ...
a simple way to find out is simply to go ask DMM ... however that tends to be out of favor on RC ... as then we wouldnt get 10 pages+ of "experts" arguing ...
maybe ill shoot em an email since i do have revolvers im using ....
(This post was edited by bearbreeder on Dec 16, 2011, 10:51 PM)
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mattm
Dec 16, 2011, 11:06 PM
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bearbreeder wrote: interesting ... a simple way to find out is simply to go ask DMM ... however that tends to be out of favor on RC ... as then we wouldnt get 10 pages+ of "experts" arguing ... maybe ill shoot em an email since i do have revolvers im using ....
Post if you do so I don't hit them with the same thing. I was going to but haven't motivated yet.
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bearbreeder
Dec 16, 2011, 11:09 PM
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ill let you do the honors matt ... i dont use my revolvers for that purpose so its more relevant for you
i use em mainly to reduce drag on sharp turns, for redirects and for emergency pulleys
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joeforte
Dec 17, 2011, 3:37 AM
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bearbreeder wrote: interesting ... lets take the worst case scenario ... no friction on the top piece ... does it increase or reduce the force on that piece ... i think most would agree that the force would be very high ... the test of course is fairly simple .. simply clove yrself into a piece and throw yrself off ... if u dare so as friction is reduced, i suspect well tend to see a bit less force on the last piece ...
This is my thinking as well. not simple physics, but I can't see how it could increase the force. The clove hitch comparison is right on. Yeah there's no pulley effect, but the fall factor is much higher when there is more friction (2 if you're cloved). This is due to the shorter working length of rope available to the system to dissipate the energy.
As a bonus, it is really easy to give a SMOOTH catch on a revolver, as long as the belayer is aware of it. I always warn my belayer when I use my revolver/screamer combo, and my partner wears nice soft leather belay glove!.
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6pacfershur
Dec 17, 2011, 4:05 AM
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thanx for the link mattm.... (everyone knows how much i like them)
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mattm
Dec 17, 2011, 6:22 PM
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joeforte wrote: bearbreeder wrote: interesting ... lets take the worst case scenario ... no friction on the top piece ... does it increase or reduce the force on that piece ... i think most would agree that the force would be very high ... the test of course is fairly simple .. simply clove yrself into a piece and throw yrself off ... if u dare so as friction is reduced, i suspect well tend to see a bit less force on the last piece ... This is my thinking as well. not simple physics, but I can't see how it could increase the force. The clove hitch comparison is right on. Yeah there's no pulley effect, but the fall factor is much higher when there is more friction (2 if you're cloved). This is due to the shorter working length of rope available to the system to dissipate the energy.
A more efficient pulley (lower friction) will INCREASE the force at the pulley point (anchor).. It's why you want larger pulley with ball bearings etc etc. for hauling, especially with a moving pulley setup. Mind you this is simple physics and not accounting for the dynamic load absorption of the rope (hence the complications below).
See here: http://www.southeastclimbing.com/faq/faq_pulley.htm
Clove Hitching into the piece eliminates the "pulley effect" which completely changes the loads. a FF2 onto a piece will have LESS force than a 1.78 with a pulley effect. Hence the debate about clipping into your anchor as the first piece while leading.
Like I said, It's NOT AT ALL SIMPLE. The more I look into it the more I see that you'd have to do a lot of testing and the answer will CHANGE depending on the factors involved; Fall Distance, Rope Out, Rope Dynamics etc etc.
A pulley MIGHT be beneficial in certain circumstances but detrimental in others. You can't come up with simple examples and call it good.
Jim Titt points out how complicated it is commenting on a fall force calculator posted online:
In reply to: The karabiner factor is certainly complicated, it is possible to create a model using various fall factors and rope velocity but you need to do a lot of testing to get it accurate. (Iīve got a model but it is not for publication). At the moment the best you can do is work on a factor of about .3 for small falls (less than FF0.4) and 0.65 for big ones (over FF1) and 0.5 for the rest. Unfortunately fall distance also plays a role so if itīs a big long one then some adjustment is needed but this is going to be complicated. .... The biggest problem with this sort of calculation or model is that there are many more dynamic effects in the system which are not generally identified correctly, the most common being the hysteresis in the frictional effects (belay device and karabiner) which make some pretty drastic differences to some of the numbers. Jim Titt"
(This post was edited by mattm on Dec 17, 2011, 7:05 PM)
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bearbreeder
Dec 17, 2011, 7:30 PM
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lets just ask DMM
if anyone tests things ... they do
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JimTitt
Dec 18, 2011, 2:48 PM
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The real complication is that in normal circumstances the impact on the tope piece is limited by the force applied in the belay device, say 2.5kN for a ordinary plate and belayer. This force then gets modified through the intermediate gear until it is applied to the top piece.
With no intemediate gear and no friction at the top piece youīd be looking at a maximum of 5kN no matter what the fall factor was, directly tied the maximum is going to be the rating of the rope for a FF1.77 but obviously lower for a smaller FF.
Add intermediate gear with a normal belayer and the the maximum force possible starts to wander up towards the fixed rope case but there will always be more rope in play so the FF must be lower.
Reducing the friction through the system would give considerable advantage for a good dynamic belayer to reduce the loading, personally I canīt really see any circumstance one would normally encounter where the force would actually be increased but I might want to think about this a bit more!
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mattm
Dec 18, 2011, 3:25 PM
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Thanks Jim for the qualifications. Any comments on what a "non-dynamic" device (GriGri etc) would do to the system and loads?
Starting to think my revolvers might get some more use reducing rope drag...
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joeforte
Dec 18, 2011, 11:45 PM
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JimTitt wrote: Reducing the friction through the system would give considerable advantage for a good dynamic belayer to reduce the loading, personally I canīt really see any circumstance one would normally encounter where the force would actually be increased but I might want to think about this a bit more!
Thanks for the input Jim.
As I said above, I always let my belayer know when I place a revolver. If the belayer does not know it has been placed, it's advantages are minimal, and sometimes can be even detrimental. The belayer must be ready for a much higher force than normal, allowing them to dissipate the forces that would have normally been taken by the pro.
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