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gym to outdoors / top-rope to multipitch


Gary_Yngve

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Ive used the prusik above the device too. It works well also but you might get it hung up tight - then you just have to make a loop in the rope(s) below you to stand up thus giving you slack in the prussik enough to loosen it. Not to bad, but a bit less convenient than the auto block-break method.

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All quoted from

http://storrick.cnchost.com/VerticalDevicesPage/Misc/RappelSafetyPost.html

 

Al Padgett and Bruce Smith's discussion of the Prusik Safety in On Rope (National Speleological Society, 1987) explains "It was learned through several bad accidents that if a problem occurs, instead of letting go, the natural reaction is to grab. Grabbing a Prusik allows it to slide down the rope, travelling faster every instant. If a person is actually able to come to his senses long enough to let go of the knot, the sling material may disintegrate, allowing the climber to descend even more rapidly than before. In actual usage, the Prusik safety has proven to be troublesome and dangerous". They then mention the Spelean Shunt, Safety Rappel Cam, and Petzl Shunt as options, but correctly note that "No self-belay device should interfere with rappelling technique. If it does interfere, it is counterproductive in that it exists to help control a problem, but instead tends to create one.

 

One last quote, from John Long, on page 155 of the second edition of How To Rock Climb: "A sliding knot backup (commonly referred to as a Prusik backup) is rarely if ever used as a normal procedure. If you don't know how to rappel, get a belay. If you are doubtful that you can make a certain rappel, don't make that rappel. Only if you are doubtful and must rappel, and no belay is possible, should you consider the Prusik backup as an option....All told, the Prusik backup is a highly contested technique. The only thing for certain is that it can be highly problematic."

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When I learned about the autoblock method of putting a friction knot below the device, I thought "this is great, much better than putting it above." Well, now I have changed my mind. Why?

 

Only if the friction knot is above the belay device is there even a chance that it will save you if you rap off the ends of the rope. [i fear that in practice, you'll be holding the knot, and you'll still die.]

 

Second, I have come to realize it is pretty darn easy to free up the friction knot if you you accidently let it grab, as mentioned above, by simply wrapping the rope around a foot and standing.

 

I'd like to hear one example of a prussik saving someone from rapping off the end of the rope.

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Also, In trad environment, I NEVER intentionally fall

 

i routinely push myself in both environments and fall often on gear and bolts...

 

if the gear is adequate and you've placed it properly than bombs away...if there is no gear (or it sucks), don't get in over your head and downclimb...

 

once again, it boils down to the grey matter that's driving the whole system...

 

dogma this and dogma that is just flat stupid...you got a number 2 cam buried in competent granite with no possible ledge smacks? Well, what's the difference between that and a bolt????

 

maybe you are unsure of you gear skillz?

Edited by RuMR
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I find an autoblock backup most useful for when I know I'll have to do something while rapping, like free a stuck rope or gear, or look around for the next rap station. Then I can do whatever it is with two hands and peace of mind.

 

It might not save you from rapping off the end, but a backup might keep you safe while you try to unfuck yourself after seeing two uneven ends slide toward your brake hand well short of the next anchor.

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I thought the prussik backup on rappel, above or below the device, was supposed to be a backup in case of things like climber on rappel gets knocked unconscious by falling rock, or has a heart attack, or things like that... pretty unlikely but it seems in general we backup a lot of systems (equalized anchors, several pieces of protection per pitch, double biners with opposing gates), but not on rappel.

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I find an autoblock backup most useful for when I know I'll have to do something while rapping, like free a stuck rope or gear, or look around for the next rap station. Then I can do whatever it is with two hands and peace of mind.

 

It might not save you from rapping off the end, but a backup might keep you safe while you try to unfuck yourself after seeing two uneven ends slide toward your brake hand well short of the next anchor.

 

you can adjust the lengths of ropes while on rappel quite easily by locking one strand and rapping the other...

 

also, two wraps around a leg with a hitch on the weighted strand will lock one off...

 

FWIW i don't rap with prussiks or autoblocks and haven't gotten into trouble yet...who just raps down the rope without looking below???????

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Dru and Dmu got both worries about the above the device prussik down. Picture rapping merrily away down a rope with your right hand braking on the rope and the left hand tending the prussik. Now, unexpectedly the end of the rope shoots through your brake hand. What do you do? You probably don't have a lot of time to think and very likely, you are going to reflexively clutch hard on the rope above you with the prussik-tending hand, basically disabling the prussik.

 

There was an article on this on rec.climbing a long time ago about people trying this out. Here people purposely rapped off the end of a rope (with a toprope backup of course) and many of them couldn't get themselves to not grip the prussik even though they knew what was coming.

 

I'm not sure that the prussik below the device wouldn't have the same problem though. Basically, a prussik has much less chance of saving you from rapping off the rope than you might think.

 

A prussik is pretty nice to have if you have to stop on the rap very near the end of the rope when you get wigged and decide that you shoulda knotted the ends together afterall! Much more secure-feeling that the old leg wrap.

 

Prusik below the device is easier to loosen up and start rapping again without having to get your weight off the rope (good thing on an overhanging rap).

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I'd only really want to do the length adjustment you're talking about in certain situations. It sounds like it'd put a lot of friction on the rope (against rock and anchor point).

 

The leg wrap thing is good. I just slap on an autoblock when I know in advance I'll want to do lots of two-handed futzing around on the way down.

 

Ten seconds for a little peace of mind is worth it to me, when I think it'll be useful.

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I'd only really want to do the length adjustment you're talking about in certain situations. It sounds like it'd put a lot of friction on the rope (against rock and anchor point).

 

In my experience it is very difficult to do the length adjustment thing while you are hanging on the rope. A better way (if possible) is to get your weight off the rope temporarily and do the adjustment, then continue rappelling. You can either do this by getting a good stance on the wall (a bit sketchy), or by clipping into a piece of gear/bolt momentarily while you make the adjustment.

 

Marking the middle of your rope (and re-marking it when necessary) is a great way to avoid this situation as well as save a lot of time on every rappel.

 

 

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Leg wrap sure as hell isnt gonna stop you from rapping off the rope.

 

Mostly I use a prussik when scrubbing to clean a route. But I have started using it in the mountains and ice climbing because of the "rockfall - unconscious" scenario.

and maybe a prussik will and maybe it won't...why not just not rap off the end of your rope??

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I'd only really want to do the length adjustment you're talking about in certain situations. It sounds like it'd put a lot of friction on the rope (against rock and anchor point).

 

I had to do it once. I got to where I saw that I wouldn't reach the anchors because one of my two ropes was shorter than the other. There were no knots and I stopped about ten feet from the end. I found myself quite alarmed at the situation. First I put on some leg wraps. Then I pulled up the ends and tied knots. Now I felt a lot better. Then I put on an autoblock. Finally, I was able to let the longer rope out and thank God the knot was on the right side of rap ring to allow this, otherwise it would have been a long way to prussik back to the anchor.
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Leg wrap sure as hell isnt gonna stop you from rapping off the rope.

 

Mostly I use a prussik when scrubbing to clean a route. But I have started using it in the mountains and ice climbing because of the "rockfall - unconscious" scenario.

and maybe a prussik will and maybe it won't...why not just not rap off the end of your rope??

 

It's horses for courses Rudy!!!!! A racehorse isn't any good at plowing a field.

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