Short Drop Problems

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Short Drop Problems

Postby Scott McCrea » Mar 31, 2009 2:56 pm

At our most recent vertical practice session, one caver asked why he should be prepared to do a changeover on a simple 20' drop. Anyone have some examples of real-life problems that have happened on short drops? I'll start:

Hair or clothing stuck in descender.
Helmet and light fell off.
Snakes on the floor (a la Raiders of the Lost Ark).
Rope damage.
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Re: Short Drop Problems

Postby Carl Amundson » Mar 31, 2009 3:08 pm

Bad air (from decaying deer carcass)
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Re: Short Drop Problems

Postby Vertigo » Mar 31, 2009 3:16 pm

Unstable rocks or a false floor :yikes:
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Re: Short Drop Problems

Postby cavedoc » Mar 31, 2009 3:20 pm

Rope didn't really reach the bottom.
Mostly it's just that if you're always prepared, then you'll be prepared when you really need to be. The drop is not going to announce to you that you'll need to do changeover. I suspect most Froggers are ready to do this by nature of their climbing system. Is this more of a concern for a Rope Walker user?
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Re: Short Drop Problems

Postby Vertigo » Mar 31, 2009 3:27 pm

Pool of water on the bottom is deeper than you thought it was...oh no! A siphon!
:scuba: Or maybe you forgot the carabiner you were supposed to have for that rebelay :doh:
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Re: Short Drop Problems

Postby Scott McCrea » Mar 31, 2009 3:36 pm

Good ones, Thanks!

But, what about if you are not the first one down? Say you are the fourth one down and all those things have been checked?
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Re: Short Drop Problems

Postby NZcaver » Mar 31, 2009 3:48 pm

Scott McCrea wrote:Hair or clothing stuck in descender.
Rope damage.

Check (not personally, but watched a friend get her hair stuck in a rack).
Check.

cavedoc wrote:Rope didn't really reach the bottom.

Check.

Vertigo wrote:Pool of water on the bottom is deeper than you thought it was...

Check.

Plus:
Got on rope and realized something was left behind (either at the top of the drop, or at the bottom).
Started climbing and dropped something (usually a glove).
Rappelled past a rope pad/rebelay/redirect and then realized it should be repositioned or otherwise adjusted.
Started rappelling and decided that the rope should be re-rigged in a different place for safety or efficiency reasons.
Started rappelling or climbing and then realized a person at the top or bottom needs additional instruction or assistance.
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Re: Short Drop Problems

Postby ron_miller » Mar 31, 2009 8:51 pm

Real example - a light caver was rappelling a short drop on a very old, stiff and dirty PMI Pit Rope using a micro-rack and all four bars. The individual got partway down the short drop with great effort, but the friction was such that they were unable to continue down, and they were unwilling to try to drop a bar (which of course would have effectively dropped two bars).
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Re: Short Drop Problems

Postby NZcaver » Mar 31, 2009 8:58 pm

ron_miller wrote:Real example - a light caver was rappelling a short drop on a very old, stiff and dirty PMI Pit Rope using a micro-rack and all four bars. The individual got partway down the short drop with great effort, but the friction was such that they were unable to continue down, and they were unwilling to try to drop a bar (which of course would have effectively dropped two bars).

How about carefully switching to 2 bars + the hyper bar? :shock:

I know, I know... more bad practices being encouraged on internet forums. :shhh: :tonguecheek:
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Re: Short Drop Problems

Postby fuzzy-hair-man » Mar 31, 2009 9:15 pm

Scott McCrea wrote:Good ones, Thanks!

But, what about if you are not the first one down? Say you are the fourth one down and all those things have been checked?


I've made it a point of principle never to get on a rope I'm not prepared to come back up, I've been on trips where doing a through trip and the rigger has been like we are only going down the rub won't be bad etc, I was not very happy about it, :evil: each caver IMO should be able to act independently as the situation dictates and able to escape as an individual, I don't think you can really foresee all of the situations that might need you to perform a changeover or otherwise have your full capability, also what one caver is happy with another is not so the 4th or whatever guy down might want/need to bug out or change things as NZ pointed out, as far as bad air goes some people can detect it more readily than others it may be the 4th person down is the one that goes "I don't like the air in here, let's go".

I remember reading one an accident report about a group going into a wet cave, it turned out the leader didn't have their ascending gear and couldn't turn around when they realized the cave was in flood and because of the roaring water communication was difficult, it worked out that 1 or 2? people drowned because they had to try to swim, it was really a tragedy that could have been easily avoided several times over if each caver had their ascending gear on them. The report was trying to highlight how errors tended to compound one another but the point I took away was that the whole thing could have been SO easily avoided if at least some of the party had their ascending gear on them. :hairpull: OK so It's probably not a short drop... :roll:

The other thing is what if the 3rd caver down needs rescuing and the 4th is in the best position to do this? if their ascenders are at the bottom of the pitch they're useless. :down:
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Re: Short Drop Problems

Postby cavedoc » Mar 31, 2009 10:59 pm

Scott McCrea wrote:But, what about if you are not the first one down? Say you are the fourth one down and all those things have been checked?


I guess it's a question of whether one is going to be independant on rope or not. Personally, I have no interest at all in being dependant on rope. I'll get flamed for saying "That's just the way you do it," but that's how I feel about it. And I don't want to go caving with someone who is not independant on rope.
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Re: Short Drop Problems

Postby ron_miller » Mar 31, 2009 11:09 pm

NZcaver wrote:How about carefully switching to 2 bars + the hyper bar? :shock:



Given the huge amount of friction in this instance and the absolute lack of progress with four bars, I suspect that probably would have worked just fine, though I admit I have never tried it (that'll be tomorrow's tree practice endeavor, only a few feet off the ground, of course!). Given that the friction was so high, the individual might have been able to push the top two bars up as much as possible, carefully pulled out a bight of rope from on top of the third bar, placed the bight over the hyperbar, removed the fourth bar, and continued to the bottom. However, I believe the individual had been fully indoctrinated in the dogma that anyone who rappels using a micro-rack in the infamous "C" rig (two bars and a hyperbar), regardless of actual conditions, is a post-mortem ACA article waiting to happen, so they never would have even tried that.

The point, of course, is that if you have so much friction on your rappelling device that you can't continue downward, and for whatever reason you're unwilling or unable to reduce that friction while on rappel, you need to be able to do a changeover, at least so you can unweight your rappelling device and adjust the friction while it is unloaded.
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Re: Short Drop Problems

Postby Stridergdm » Apr 1, 2009 7:11 am

Yeah, I'm sort of along the side of "because". :-)

And the bad rope happened to me. In Ellison's.
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Re: Short Drop Problems

Postby Scott McCrea » Apr 1, 2009 7:55 am

NZcaver wrote:How about carefully switching to 2 bars + the hyper bar? :shock:

I always tell my rack learning students that if you think you need to go less than 4 bars, that is your cave-god telling you to go home--this is not your day to be on rope.
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Re: Short Drop Problems

Postby Scott McCrea » Apr 1, 2009 7:58 am

Thanks again for examples. This will give me good ammo when I scream lecture remind them about safety at the grotto meeting Friday night.
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