Self-locking descender for rappelling

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Re: Self-locking descender for rappelling

Postby OpenTrackRacer » Jul 2, 2008 1:30 am

I'll have to do more research on HHS. It's much more serious than I'd thought. Sometimes it seems you can't win... you use a locking descender to keep from falling if injured and then die because you're hanging from the rope. Cruel.

I really appreciate your feedback on the Stop. I guess something like the Petzl Simple would be a straight bobbin style descender and the Stop (or Indy, etc.) adds the lock. I know what you mean about bad habits but the real goal is a backup to falling if the rope is released. I'm perfectly comfortable descending on an ATC but if something happens and I lose the rope I'm in big trouble real fast. Grabbing the handle is a downside of the Stop but I believe it's something you can train for. From what I've read I'm worried that the double stop types may not work well at all on stiff rope like we're using.

I guess everything is a trade off. I'm going to get some cord and mess with the French Wrap and autoblock as well (without modifying my harness). It's virtually free so why not experiment.

I've also sent an e-mail off to our local grotto. I'm sure we'd like caves too and could learn a lot.

I'm going to call Petzl tomorrow too and ask some questions about the Stop.

Thanks again!
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Re: Self-locking descender for rappelling

Postby OpenTrackRacer » Jul 2, 2008 1:40 am

One more question... I see that Petzl also has instructions for using the GriGri as an autolocking descender for rappelling. It's not for long descents but seems like it might be a match for what we're doing.

Any comments on the GriGri versus the Stop?
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Re: Self-locking descender for rappelling

Postby ek » Jul 2, 2008 1:45 am

Stridergdm wrote:As for seeking help, if you're not familiar with with Harness Hang Syndrome. In the time it takes to get help, your stuck person may go from a slightly injured person to one who is severely medically compromised. If nothing else, get someone to teach you how to do a 2 rope pick-off and make sure you've got a 2nd rope ready to go.

Or use one rope, twice the length of the drop, rigged in the middle with a fixed brake lower (e.g. a descender rigged to a fixed point) locked off. If someone is stuck, unlock the fixed brake lower and slowly lower them to the ground.

Failure to operate a fixed brake lower correctly kills at most one person, which automatically makes it, in a way, twice as good as bringing a second rope with the intention of doing a pick-off if someone is stuck. Rigging with a fixed brake lower is also hugely simpler and easier.

The disadvantage of the fixed brake lower for this is that while a second rope can be a second rope to any other rope that is rigged, you'll need a huge amount of extra rope if you want to have a large number of (perhaps consecutive) drops rigged simultaneously with fixed brake lowers capable of lowering all the way from the top to the bottom.

OpenTrackRacer wrote:Grabbing the handle is a downside of the Stop but I believe it's something you can train for.

Why do you believe that?
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Re: Self-locking descender for rappelling

Postby OpenTrackRacer » Jul 2, 2008 1:57 am

Because grabbing the device is an instinctive panic reaction. Proper training and practice is what makes the difference between panicking and reacting intelligently.

It's the same for working with ropes and any other hazardous or high stress situation.

Don''t tell me you believe the "grab" reaction is impossible to overcome?

ek wrote:
OpenTrackRacer wrote:Grabbing the handle is a downside of the Stop but I believe it's something you can train for.

Why do you believe that?
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Re: Self-locking descender for rappelling

Postby fuzzy-hair-man » Jul 2, 2008 2:28 am

OpenTrackRacer wrote:Don''t tell me you believe the "grab" reaction is impossible to overcome?


I don't believe it's impossible to overcome but I'd say it's VERY hard to overcome and unless you're going to do the experiment* then I'd say it's impossible to know how you'd react.

*there's a rig where it's possible to test the tendency to squeeze or let go as a reaction to falling using prusik loops as a backup for a rappel. I seem to remember the majority by a long way could not break the reaction to squeeze. This is the main reason why if you have a prusik safety it's better below your descender and held open by your brake hand, plus it leaves your non brake hand free for other stuff.

If you practice rappelling with your hand on your rack frame or bobbin frame this reaction could help if you loose the end of the rope.
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Re: Self-locking descender for rappelling

Postby NZcaver » Jul 2, 2008 2:40 am

OpenTrackRacer wrote:Hi! A group of friends and I are into exploring old mines. We've been going down on ropes using ATC and figure eights for a while. We've started to be concerned about the possibility of being hit by falling debris or missing a foothold and getting stunned while descending.

I've started doing research into self-locking descender devices like the Petzl Stop or GriGri but I wanted to get feedback from experienced users.

The idea would be to stop an uncontrolled descent if one lost the free end of the rope or was even knocked out.

We use PMI 11mm pit rope which is fairly stiff. I know that can be an issue with some devices. The rope also tends to get dirty rather fast with fine dry dust.

Welcome to the forum.

The Petzl Stop is a fine descender, which should do you well for what you need. I've used a Stop for the majority of my rappels into caves, mines, and above ground over last 20 years or so. I also use racks and other descenders occasionally, but I still end up coming back to my trusty Stop. Don't bother with the GriGri - although it should work on static ropes in a pinch, it's really designed for more flexible dynamic ropes.

As Tim said, PMI 11mm can be a little stiff and slow with a Stop. But if you're able to keep the rope fairly clean and/or you weigh a little more (or your gear does), your descent shouldn't be too bad. Or you could just use 10 or 10.5mm rope, or something more flexible. Perhaps you can borrow a Stop off somebody locally, and try it out on your rope? Preferably under controlled conditions and/or being supervised by someone experienced with a Stop.

As you've seen, a number of experienced and well-meaning cavers here in the US suggest using a rack and an autobloc/French Wrap safety. That's fine, but I can also appreciate your interest in a purpose-built device like the Stop. You recently mentioned the "grab reaction" and training to avoid that with a Stop. The best advice I can give you is to treat the handle like a parking brake, not a speed control. That's what your other hand is for - the hand which should always have control of the rope unless your descender is locked off. Make sure you're controlling the rope with that hand before even touching the handle with your other hand. Then there should be no "grab reaction" issue.

If you search the forum for Petzl Stop, you should find more discussion about this going back the last couple of years. It's great that you have an interest in furthering your knowledge and skills, and are open to suggestions. Add in some training and practice in using the gear, plus some basic companion-rescue skills, and you should find yourself ahead of the curve. Good luck, and be safe.
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Re: Self-locking descender for rappelling

Postby ek » Jul 2, 2008 2:42 am

OpenTrackRacer wrote:Don''t tell me you believe the "grab" reaction is impossible to overcome?

Believing it is impossible to overcome is safe. Believing that by being experienced and comfortable using a single-stop descender, you have overcome the grab reaction, introduces risk of death. It seems to me that the burden of proof should be on those who would introduce risk of death. So I ask you--do you have any hard evidence that experienced users of autostop descenders reliably and quickly release the handle when entering into an uncontrolled slide down the rope?
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Re: Self-locking descender for rappelling

Postby NZcaver » Jul 2, 2008 2:52 am

ek wrote:So I ask you--do you have any hard evidence that experienced users of autostop descenders reliably and quickly release the handle when entering into an uncontrolled slide down the rope?

I don't know about you, but I prefer never to enter into uncontrolled slides down a rope. We are presuming if one were to suddenly lose consciousness, one would let go with both hands - releasing the rope, and the handle. Eliah, you should volunteer to black out and test that theory. :big grin:

Ultimately, I see the autostop function primarily as a convenience. I use the Stop because it's comfortable, convenient and efficient for me. The safety feature is just a bonus.
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Re: Self-locking descender for rappelling

Postby hunter » Jul 2, 2008 9:48 am

:exactly: I'll second pretty much everything NZ said. I use and like my stop. It is a nice size and works well. I have run across some really old crusty 11mm rope on less than vertical drops where it was really slow but this shouldn't be an issue if you can keep your rope fairly clean.

On the Gri-gri, I use one routinely when rappelling on climbing rope and it works fine and locks better than the stop. The control is more awkward though. I suspect that a gri-gri would be a bit sticky on stiff 11mm static but I haven't tried it. The gri-gri is really designed for belaying so I would only buy it over the stop if you want to use it for such.

On HHS. All the info being posted is worthwhile and you should know it. At the same time don't get hung up on HHS as a reason to not use a safety or autostop sort of device. If you lose control for some reason you are dead immediately. If your autostop catches you there is at least a chance for someone to save you.

Believing it is impossible to overcome is safe. Believing that by being experienced and comfortable using a single-stop descender, you have overcome the grab reaction, introduces risk of death. It seems to me that the burden of proof should be on those who would introduce risk of death. So I ask you--do you have any hard evidence that experienced users of autostop descenders reliably and quickly release the handle when entering into an uncontrolled slide down the rope?


To me the point is that the Stop should not be treated as an auto stop descender in normal use and you shouldn't train for it like it is. If you start to lose control your instinct should be to grab very hard with your break hand. This will stop your descent with a rack, 8, simple, Stop or any other rap device regardless of what your other hand does. Since rack users aren't dying off every little bit I believe that it is possible to train ones instinct to use the break hand correctly. In many ways I think anyone learning should start with something other than the Stop to correctly develop this instinct. After that you can learn the locking features of the stop as a convenience not as something to rely on in day to day use.

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Re: Self-locking descender for rappelling

Postby OpenTrackRacer » Jul 2, 2008 11:09 am

Morning all!

I agree with what NZcaver and hunter have written. I don't plan on using the Stop any different than my ATC. The descent will always be controlled with the rope hand. The only real difference would be that my other hand will be on the Stop (holding the handle down) instead of above me on the rope. The only disadvantage I see is that I won't have a free hand to use for pushing off objects or moving things while I'm actually descending.

I understand what you're trying to say Eliah but I think it applies more if you were relying on the Stop instead of using proper technique and controlling your descent with the rope. You "free" hand will already be squeezing the Stop. The advantage it adds is that if you are knocked our or stunned, you have some sort of backup to simply falling down the rope.

Besides, you can indeed train for the proper use of the Stop or pretty much anything else. I don't know if you're old enough to have experience with non-ABS brakes on low friction surfaces. The gut reaction of most people is to slam on the brakes and hold them if they're about to have an accident. Proper technique is to release the brakes until the wheels are turning (so you regain steering input) and them modulate them to control the vehicle. That's a similar life and death high stress situation and with proper training and education it's quite natural to take the proper action.

Losing control of the rope in normal situations is unlikely. As hunter said, you don't hear about people doing it too often. With a rack, ATC, figure 8, etc. there is no backup. Lose the rope and you're gone. At the same time, you don't hear about people working the Stop wrong and falling often either.

I think it's just like everything else with ropes. Proper training and practice is required.

Thanks!
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Re: Self-locking descender for rappelling

Postby hunter » Jul 2, 2008 11:40 am

you don't hear about people working the Stop wrong and falling often either.


Well, not to shoot a hole in my own argument but I have actually heard of this happening a few times (it is mentioned in one of the old threads about the stop). To my knowledge this always occurs with someone learning to rappel on the stop. They let go with their break hand to do something and then push the lever. When the start to fall they push the lever harder and crater. Hence my observation that it is key to learn with something else so the break hand instinct is developed.

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Re: Self-locking descender for rappelling

Postby OpenTrackRacer » Jul 2, 2008 11:45 am

Interesting. I just got off the phone with Petzl. I went through the scenario with them and they suggested that the GriGri (or I.D. if I wanted the panic feature) would be a better choice than the Stop. They thought that the rope would flow better while descending. Also, since it totally locks when released (rather than creeping like the Stop) it would be more appropriate to our application.

Thoughts?
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Re: Self-locking descender for rappelling

Postby Tim White » Jul 2, 2008 2:02 pm

The GriGri does not work well on Pit rope, it's to stiff IMO.

Keep your rope clean and prepare to spend some big $$ for the I'd. This is the most common descending device used by professional rope access technicians. A SOLID piece of equipment, but it would never hold up in a cave environment due to the working mechanisms vs mud.
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Re: Self-locking descender for rappelling

Postby Carl Amundson » Jul 2, 2008 2:26 pm

I would still go with a micro-rack and use a French wrap for your backup.
A BMS micro-rack is rock solid and with the addition of a french wrap there is no way you will get into a free-fall situation.

As others have mentioned, if you are worried about having someone unconscious on rope use twice as much rope as you need for the drop.
Drop half if it into the pit and the extra length can be use to lower someone to the bottom using a fixed break lowering technique.
You would just need to buy an extra figure 8 (steel) for this technique.
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Re: Self-locking descender for rappelling

Postby OpenTrackRacer » Jul 2, 2008 5:06 pm

Well, well well...

Just got back from a trip to my friendly neighborhood REI store. I went over to take another hands on look at the GriGri and Stop as well as loading them with Pit Rope and getting a bit of the feel for how they feed. From that experiment, the Stop did indeed seem to be better despite what Petzl had told me on the phone.

However...

Chatting with the guys at REI, one with a lot of climbing experience said he uses a Petzl Shunt (which is basically a mechanical Prusik) with a figure 8 or ATC. I messed with it and then did some more research and it now I'm really glad I went to REI. This device is perfect. It can be used with our current descending gear, it's simple to operate, keeps the hands where they should be and offers a second point of attachment to the rope. As an added bonus, it address the free hand issue since you can move it down the rope and then descend a bit on the ATC (with your other hand on the down rope of course) and use have a hand free for pushing off, etc.

Sometimes you end up with a solution that's completely different from where you started.
Last edited by OpenTrackRacer on Jul 2, 2008 6:55 pm, edited 1 time in total.
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