Dropping a rope into a cave

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Dropping a rope into a cave

Postby CavemanCroatia » Jun 20, 2012 10:46 am

Hello,
I have question. If you want to drop a rope verticaly 100m wit a bag what is a right way to do it
?
Thank you
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Re: Dropping a rope into a cave

Postby Caver John » Jun 20, 2012 12:46 pm

Uhh yell rope, and drop it?
Am I missing something?

I guess if there's already a rope rigged and one wants to drop a second rope, there could be an issue with getting the second rope tangled in any redirects or rebelays Below from the first rope. This could be a problem.
In this case, as long as the drop isNt too long, one could strap the rope bag to their leg or harness below them and let the rope self feed out. This could cause tangling though too.
Last edited by Caver John on Jun 20, 2012 1:19 pm, edited 1 time in total.
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Re: Dropping a rope into a cave

Postby tncaver » Jun 20, 2012 1:00 pm

Actually dropping a rope down a deep drop (even in a bag) could cause damage to the rope. Not advisable.
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Re: Dropping a rope into a cave

Postby Caver John » Jun 20, 2012 1:17 pm

Please explain
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Re: Dropping a rope into a cave

Postby tncaver » Jun 20, 2012 1:39 pm

The rope could be sliced by sharp fins of rock (quite common on solution pit walls) as it goes down the pit at the speed of gravity. It could also be cut in two or damaged severely by sharp rocks when it hits the bottom of the pit. It's that sudden stop when landing on hard on sharp objects that can cause damage. Unless the bag is made of Kevlar it seems unlikely that it would give adequate protection to a rope. Rope tangle can be a problem as well. Rope tangle could prevent the rope from reaching the bottom of the drop and could create a rappelling hazard going down.
Carrying a rope down is recommended. This could be accomplished with the coil over the shoulder or hung from the bottom of the rappelling
device by a tether (with or without a bag).
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Re: Dropping a rope into a cave

Postby Chads93GT » Jun 20, 2012 2:06 pm

Yelling rope and chucking the rope into the pit is very unsafe and very lazy. Take the time to either A. Hand over hand lower the rope into the pit, B. rappel with the rope in a bag teathered to your harness or B. if its really long (fantastic pit) then use your rack to control the rope going in.

As said above, sharp flakes on the walls can destroy ropes traveling at high speeds, not to mention sharper rocks lying on the ground where the rope lands, afterall, its traveling at a high rate of speed, pretty much the same speed you would be traveling if you fell into the pit, and that fall will kill you, no?

You dont get to simply drop your rope off the bridge at bridge day for a reason. Its not safe.
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Re: Dropping a rope into a cave

Postby Chads93GT » Jun 20, 2012 2:09 pm

also, rappelling with the rope in a rope bag, tethered to your harness/rack should NEVER tangle up coming out, unless the person who stuffed the rope did it WRONG.
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Re: Dropping a rope into a cave

Postby Anonymous_Coward » Jun 20, 2012 3:01 pm

I have also heard when throwing a rigged rope down a deep pit, the end of the rope can whip at speeds approaching supersonic, creating forces that the rope was not designed to handle.
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Re: Dropping a rope into a cave

Postby Chads93GT » Jun 20, 2012 3:06 pm

considering if the rope is BARELY long enough, or a foot or so short, the end of the rope can crack like a whip.

Any guesses at how fast a whip has to travel to crack?

the speed of sound.

without looking it up, thats what....760 miles per hour? Yeah............
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Re: Dropping a rope into a cave

Postby Scott McCrea » Jun 20, 2012 3:29 pm

So, this was not a good idea?

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Re: Dropping a rope into a cave

Postby NZcaver » Jun 20, 2012 3:31 pm

tncaver wrote:Actually dropping a rope down a deep drop (even in a bag) could cause damage to the rope. Not advisable.

Chads93GT wrote:Yelling rope and chucking the rope into the pit is very unsafe and very lazy.

Huh. Haven't done this much recently, but I used to throw my rope bag into pits (deploying the rope as it goes) rather frequently. Sometimes even without the bag. In about 20 years I don't recall ever having a problem. No rope damage, no unbalanced universe, just a quick and efficient (lazy??) way of getting the job done. However I recall in some particularly loose, gnarly or convoluted pits we would rappel with the rope bag hanging below deploying rope as the first person descended.

Anonymous_Coward wrote:I have also heard when throwing a rigged rope down a deep pit, the end of the rope can whip at speeds approaching supersonic, creating forces that the rope was not designed to handle.

Call be a skeptic... but really dude? Supersonic?? :shock:


Scott McCrea wrote:So, this was not a good idea?

I don't see that being a problem, but one could argue it was less "dropping" more "feeding." :shrug: "Rope, rope, roooooooooooope!"
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Re: Dropping a rope into a cave

Postby PeterFJohnson » Jun 20, 2012 4:23 pm

NZcaver wrote:Call be a skeptic... but really dude? Supersonic?? :shock:


I have dropped a rope and seen it crack like a whip with no apparent damage to the rope. I didn't pull test it afterwards so I am not suggesting you try it, but just saying. It wasn't, however, in a cave.

But if it is true that the cracking sound comes from the rope breaking the sound barrier than it is indeed going supersonic - somewhere over 700 miles per hour at the end of the rope. I will say that regardless of how fast it is going, I would make damn sure nobody is below you when you drop it...
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Re: Dropping a rope into a cave

Postby wyandottecaver » Jun 20, 2012 4:40 pm

In my experiance chucking a rope down a pit is like using a biner dropped from moderate height. It probably doesnt hurt anything most of the time, but it might create an unnecessary risk 1 time. In the case of life support equipment that is supporting MY life, unneccesary risks are unacceptable risks.....
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Re: Dropping a rope into a cave

Postby Chads93GT » Jun 20, 2012 4:48 pm

This topic will always have two sides. One side is slower lower of ropes, and the other is yelling rope and chucking it into the hole, lol. While we may not all agree on how safe or unsafe it is, i think we can all agree that if you were at the bottom and you got hit by the rope bag with 10-30-50-100 feet of rope still in it, it is going to make you have a bad day. lol
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Re: Dropping a rope into a cave

Postby Marlatt » Jun 20, 2012 4:49 pm

PeterFJohnson wrote:
NZcaver wrote:Call be a skeptic... but really dude? Supersonic?? :shock:

I have dropped a rope and seen it crack like a whip with no apparent damage to the rope. I didn't pull test it afterwards so I am not suggesting you try it, but just saying. It wasn't, however, in a cave.


Several years ago we were rigging Guaguas (~700ft), and (due to some confusion while feeding the rope from a couple large duffel bags), ended up with a long loop hanging about halfway down the pit. We dropped the free end, and the end of the rope cracked - I don't recall it being audible, but you could see the tip snap around. After dropping the pit, we discovered that the core was blown out through the side of the mantle a foot or so from the end of the rope! This was nearly-near PMI. Needless to say, I learned a lesson about rigging big drops.

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