rope

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rope

Postby machine23 » Jan 3, 2008 2:28 pm

there are more types of climbing rope than i thought. which type for caves? no hefty rock climbing for me. just a better way to lower myself and my buddy into a cave. or possibly up into one. and also harnesses. went to REI. they had padded and non-padded for those of us on a tight budget...(me). i want comfort in a harness. which one do any of you use, and would you recommend it. :calvin:
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Re: rope

Postby Dwight Livingston » Jan 3, 2008 3:33 pm

Lowering your buddy? You sound like you are attempting to figure out this vertical caving thing on your own. Using the correct rope is only one of many important issues. I'd suggest that the best way to find answers to these and many other vertical questions is to find a group of experienced and competent vertical cavers, see how they do it, and practice in controlled conditions. You need to learn the ropes, the hardware, the techniques, the issues, before attempting anything in a cave.
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Re: rope

Postby ek » Jan 3, 2008 4:22 pm

Dwight Livingston wrote:Lowering your buddy? You sound like you are attempting to figure out this vertical caving thing on your own. Using the correct rope is only one of many important issues. I'd suggest that the best way to find answers to these and many other vertical questions is to find a group of experienced and competent vertical cavers, see how they do it, and practice in controlled conditions. You need to learn the ropes, the hardware, the techniques, the issues, before attempting anything in a cave.

:yeah that:

machine23, you'll want to seek instruction from experienced vertical cavers before going vert caving...and you'll want to start out doing it with experienced vertical cavers too. If you have background in rock climbing, that will help you some, but there are some very significant differences. In general, cavers are very willing to introduce you to vertical caving and to provide you with instruction to the best of our abilities. A good place to start would be through your nearest NSS grotto (which you may or may not already be involved with).

To address your specific questions...here is an extremely brief summarizing taste of things that does not in any way take the place of actual instruction. If not all of this makes sense (or none of it does), don't fret. You need to get in-the-flesh instruction anyway.

When vertical caving with Single Rope Technique (SRT), you rappel into the pit on a single, fixed rope, anchored at the top. To get out, you ascend the rope with mechanical ascenders or (rarely) friction hitches on the rope. (Less commonly, you will rig the rope so you can pull it down and use it for more drops in the cave--this only works for through trips from one entrance to another and once you pull the rope down from the first drop you must either complete the trip or be rescued.) An ascender when operated in the usual way can be slid up the rope but does not move down when weighted. A friction hitch can be moved in either direction when you grab and squeeze the hitch, but when weighted and not held onto it locks to the rope. This is an example of a common type of mechanical ascender. Here are some examples of friction hitches. Several other types (of each) are also used.

It is necessary to have at least two ascenders (or, rarely, two friction hitches, or one ascender and one friction hitch) because one acts as a progress capture while the other is moved up the rope--then their roles switch, and in this way vertical progression is accomplished. It is also considered unsafe in most situations to be attached to the rope by just one ascender, as ascenders can sometimes come off the rope when you don't want them to. There are many different systems for climbing rope using different kinds of ascenders in different configurations. Some climbing systems use more than two ascenders. Most use some kind of chest harness as well. Most climbing systems that are used in caving fall into two categories--sit-stand systems (e.g. frog, Texas), where you alternate between sitting and standing positions to progress up the rope, and ropewalking systems (e.g. Mitchell, double-bungie ropewalker) where you use a more natural walking motion to get up the rope. In general, sit-stand systems are more minimalist and (when properly adjusted and used with correct form) energy-efficient, whereas ropewalking systems are faster, and easier for anyone who is not tall and lanky. (Though I know quite a few people who don't fit that description and still frog well.) In the United States many different systems are used--most of the rest of the world uses the frog system almost exclusively.

A harness designed with caving in mind is almost always best. Petzl, PMI, Gonzo Guano Gear, On Rope 1, and other companies make caving harnesses. If your harness is padded, the padding should not absorb water. The harness straps should be made from sturdy, abrasion-resistant material, and designed in such a way that in case of a very bad day, it can be cut anywhere and still not drop you (check out the caving harnesses by these companies to see what I mean). If you use the frog system, your harness should have a very low attachment point (about at the hips, rather than the waist), or your ascending system will be very inefficient. Generally harnesses closed with maillons rapides (here's one of those) are best, and that's pretty much a must for an efficient frog system.

You'll probably want to use semi-static (a.k.a. low stretch) rope for vertical caving. Experienced people who know very well what they're doing and understand the specific issues pertaining to using "totally" static (a.k.a. very low stretch) rope can do that. Starting out, you should generally rappel and ascend on the semi-static rope. Dynamic (a.k.a. high stretch) climbing rope is unacceptable for vertical caving because, stretching a great deal across any rock with which it is in contact, it abrades at a dangerously quick rate. Dynamic rope also tends to have a softer protective sheath than semi-static rope so that the sheath can stretch enough to keep up with the stretch in the load-bearing core...thus making abrasion more of a problem. (Though some semi-static rope, such as PMI EZ-Bend, which *is* made for--careful--caving use has a very supple sheath.) However, dynamic climbing rope is essential for any lead climbing you might do in a cave...which you won't be doing until you have significant SRT experience.

9-11mm are the most common cross-sectional diameters for cave rope. If you're using advanced rigging and everybody knows what you're doing then you can go down to 8mm (and maybe even lower). But there is only reason to do that when you have to carry your rope a very long distance. On ropes thinner than 8mm or thicker than 11mm, many ascenders and descenders used by cavers do not function properly (or at all). Some devices only go down to 9mm. A few devices have even more specific thickness constraints.

Needless to say, when you're using a rope, somebody (you?) as to rig it. So you'll want to learn how to do that in the not-too-distant future. But first you should how to get up and down a rope (and use those skills in a cave environment).

I highly recommend vertical caving. The ropework is fun in and of itself, but also having to rappel into a cave (or part of a cave), and knowing you have to ascend rope to get out, makes the whole caving experience more immersing and amazing. Or at least it does for me.
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Re: rope

Postby David Grimes » Jan 3, 2008 4:33 pm

I was going to post some info here as well but it looks like ek pretty much said it all the answer don't get much better then that.
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Re: rope

Postby ian mckenzie » Jan 3, 2008 4:38 pm

And, in my experience, cavers are a great bunch of guys to hang out with, which is a great bonus to learning 'the ropes' from them. People on this forum will be able to help you find your local crew, if you're having trouble tracking them down.
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