Self-locking descender for rappelling

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Re: Self-locking descender for rappelling

Postby gdstorrick » Jul 7, 2012 2:11 pm

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Re: Self-locking descender for rappelling

Postby gdstorrick » Jul 7, 2012 2:21 pm

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Re: Self-locking descender for rappelling

Postby NZcaver » Jul 7, 2012 4:14 pm

gdstorrick wrote:Some of the most knowledgeable vertical cavers tell me that they avoid commenting on CaveChat because of the responses they get. I fully understand why they refuse to share their expertise.

I'm sure this is true. That said, *sometimes* with greater expertise comes a narrower mind less likely to be influenced by trivial matters like conflicting evidence and other peoples reasoning. Sometimes. In an ideal discussion people participate as equals, and the persuasive argument stands on its own merits.

And for what it's worth Gary, dogmatic is certainly not a term that springs to mind when I think of you.
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Re: Self-locking descender for rappelling

Postby Therrin » Jul 7, 2012 7:14 pm

gdstorrick wrote:
Some of the most knowledgeable vertical cavers tell me that they avoid commenting on CaveChat because of the responses they get. I fully understand why they refuse to share their expertise.


I appreciate the article you just posted. It actually has a wealth of information, as opposed to phantom paint chips or pure opinion.

These, from that article.
No rappel safety device which requires a 'negative action' to activate should be trusted…. Hopefully no more injuries will occur before cavers realize the dangers inherent in the various 'negative action rappel [safety] devices."


"During any period of unanticipated accelerating stress, a caver who is not heavily conditioned will tend to grip the rope and, in turn, the hand held Prusik, Gibbs, or Jumar."


Forgive me for asking, but wouldn't a I'D/RIG device be inherently different from a Prusik/Gibbs in terms of the gut human reaction to an uncontrolled descent? The article makes repeated reference to the instinct reaction to grab onto the rope above the device. With these devices that causes undesired results due to the fact that by grabbing the rope above the device you're actually manipulating the device to move freely on the rope.
The "negative action" involved with the RIG/I'D is different in nature. Were one to actually grip the rope in panic, the device handle would become free and the device would stop anyhow.

In that entire article, autolock descenders are only mentioned in two small paragraphs at the very bottom, and are supposed to have the same issues as those mentioned throughout the entire article above it with the Prusik backup and using the Gibbs as a backup.

Some interesting things to note:
1. Almost the entirety of the article describes the tendency to grip the rope itself during panic, which would cause *these* devices to stop.
2. The I'D has an over-pull safety on it. (though it's heavy and expensive and I admit to not having used one).
3. While it is mentioned briefly that
"One notable disadvantage of most existing autolock designs arises from the need to release the handle for the device to lock on the rope, whereas a thoughtless or panicking caver might instinctively grip the handle tighter and only worsen the situation"

It would be nice to see this tested as per the 3 rope testing method previously used to test the Prusik backup.

I like that you prefaced your article by stating:
"Safety in rock climbing lies almost entirely within this 'judgement' area. Little is left to chance. Equipment is a minor factor. With the best equipment in the world the man with poor judgement is in mortal danger".


I've only begun to use the RIG within this last year, with a previous 16 years of using conventional devices without issue. There's no piece of gear which replaces experience.

Food for thought: What if in lieu of pulling down on a handle to descend, you had to push up on one? Any chance that the ingrained human response to uncontrolled descent would be less likely to continuing to push up? (I realize this may not be practical, it's just a thought)
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Re: Self-locking descender for rappelling

Postby gdstorrick » Jul 7, 2012 8:23 pm

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Re: Self-locking descender for rappelling

Postby NZcaver » Jul 7, 2012 9:39 pm

gdstorrick wrote:This is the type of comment that upsets me. In my article, I quote a passage from the June, 1977 NSS News (p 128) and include the reference, and you pass it off as my own comment.

Goodbye.

I don't see why you're upset, Gary. Those quote boxes don't have your name at the top of each one. By specifically saying "these, from that article" I think Therrin is just asking for your feedback, rather than accusing you of something. :shrug:
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Re: Self-locking descender for rappelling

Postby Therrin » Jul 8, 2012 2:23 am

NZcaver, that is exactly what the situation was.


What an amazing ego. Perhaps if any mere mortals would like to add anything that's actually useful or thought-out, in response to my last post?

I apologize for being the first person to quote a piece of an article without giving proper footnoting or addressing that my quote was merely something I was responding to that SOME ONE said, and was not the intellectual property of the person who's article I was quoting. I'll try to add a clause to all future quoted segments so that no one gets confused. I hadn't realized that was a big issue here.
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Re: Self-locking descender for rappelling

Postby gdstorrick » Jul 8, 2012 5:35 am

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Re: Self-locking descender for rappelling

Postby Therrin » Jul 8, 2012 9:40 pm

I apparently caught the brunt of your tiredness... though unintentionally, as I was quoting the things in the article, not you personally. A quick PM could have straightened all that out.

Your collection is yours, if someone else wants a collection, tell them to make their own. :boxing:

Just got back from a mine exploring trip today to the area of Randsburg, California. :banana:
In the first mine I ended up doing 500' total of descent/ascent on rope. Ran outta rope! The shaft kept going for another 100' that I could see, and darkness beyond that. Found several dynamite boxes, and some really old false teeth.

Used the RIG for all of that, worked very well.
The first part was a 200' vertical which fed via horizontal drift to a 70deg inclined shaft which used a dual-purpose ladder, and occasionally went to 80deg.
The tops of the 4x4 side rails serve as the ore skip "tracks" and the ladder rungs are nailed on underneath (and were very thin). The ladder is ~100 years old, all but useless and is not to be trusted, would have been easier if it hadn't been there with the exception of the soft rock flaking off and pouring down below every time you touch it with your foot. The shaft was about 4ft wide by about 3ft, sometimes less, rarely more. Three rungs broke out just by resting my weight on them, and one while going down. I immediately let go of the handle and held my hand out to steady myself when that one broke, maintaining my brake hand on the rope; then thought back to this thread just afterwards.
In several sections rungs were missing entirely in long sections. Leaves you *just* enough room to ascend next to it in those sections, while rubbing on both sides.

We lit the ladder up pretty good with our headlamps here, from this point it drops at least 400' down and more that's unknown.
Image

I'll apparently have to go back with more rope!
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Re: Self-locking descender for rappelling

Postby Therrin » Sep 17, 2014 10:17 am

Well, it's been a little over two years since the last post on this thread.

And, having just now re-read the thread, I've noticed that just about the entirety of Gary's posts have been deleted from it. Kinda sad.

Anyhow, in the intervening time I've moved quite a bit, done a significant amount of rope work, even joined the NSS, and still use the RIG as my primary descending device; though I did order a micro rack just recently here....haven't gotten to try it out yet.

Doing a 2 day caving trip pretty soon, we'll see how that goes. :big grin:


Any other reports, incidents, stories, camp-fire talk, etc about the I'D/RIG?

I've had my RIG dragged all through mud/slime/junk and it has continued to function well. Wondering if anyone else has secretly or openly given it a shot....it's been a few years.
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Re: Self-locking descender for rappelling

Postby hank moon » Sep 17, 2014 12:37 pm

couple of thoughts re: self-braking descenders

- Users should be competent in rappelling with a variety of non-self-braking devices w/o a rappel backup system, and take steps to maintain that competence
- Self-braking function should be regarded as a convenience, not a safety feature

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Re: Self-locking descender for rappelling

Postby Therrin » Sep 21, 2014 6:54 am

I'd fully agree with that. It's definitely not a device you start out with, and I think they've done a decent job at not marketing it as that.

I like how you phrased it as being "regarded for convenience not safety".
Moreso, that you should not purchase it with the thought that it will be "easier" to use than other more standard devices, or that it is an "idiot-proof" device.

Selection of one of these devices should rest on a strong and safe foundation of basic skills.


With all of that considered, I'm quite fond of mine :banana:

Was up in a tree the night before last, practicing some skills and for the first time noticed some creep as I was hanging in the hard-lock position. Very slight, almost unnoticeable. Going to have to talk to Petzl about that, see about getting my cam replaced.
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