weird question about self belay
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I am not sure how you all will respond to this question. I think it is a bit unconventional. I am not a mountaineer but love to hike, hunt, and explore in the mountains. I do not "mountain climb" technically, but just go where my feet and hands can take me. Some times in descending I run into verticle walls that mean I have to back track to get around them. this is a pain to say the least. So what I wish to do is carry a very light static rope with a belay device and simple harness [I have one I use for tree stand hunting]. When I get to a cliff, loop around a tree, self belay down, and pull my rope, gently, around the tree and down and go on my way. What is the smallest diameter rope I can use? what would be a matching belay device? and what are the problems with my idea? I have rappelled with friends equipment before. I do not want to carry 10 pounds of rope etc. How about 6mm? thanks bob |
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I think a canyoneering site would be right up your alley. |
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I wouldn't rappel on any static rope under 9mm, so you won't really get a light 60m(200ft) rope. Without somewhat sketchy set-ups you would only get 100ft of lowering, which may leave you stuck at the end of a rope in the middle of a cliff, etc. |
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6 or even 5mm would probably be ok. As short as you think you'd need. I would get a CAMP Alp 95 (ultralight harness), a locking carabiner, and use a munter hitch to rappell with. Can't go much lighter than that unless you use a body belay like the dulfersitz. |
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The problem with really skinny lines i.e. 6mm is the aren't going to generate vary much friction going threw a belay device. Meaning its going to be hard to control your descent speed and create a lot of heat and wear in a small area, like on your hand, belay device ect. thin cord also cuts and wears easily over sharp edges like the edge of a cliff. |
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The problem with your plan relates not to the techinical but the practical aspects. It is all about the anchors. Sure, in most situations a single rapp would get you to the base of the cliff band. However, sometimes multiple rappels would be necessary; and suitable anchors may be scarce, especially on a talus slope above the next lower cliff band, or part way down a steep face. Getting stranded is a real possibilty. |
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For what you're talking about I'd go with a bigger static rope, like a Bluewater 11mm, and use one of the rappel devices that work with a doubled rope- ATC, Reverso, etc. Omega Pacific makes one (the SBG) that has a solid shaft (instead of a wire loop) and rappels very predictably, which you'll probably like if you're not used to doing this- It's also good with a wide range of rope diameters. You are planning to practice with this stuff before heading out, right? |
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Kent Pease wrote:The problem with your plan relates not to the techinical but the practical aspects. It is all about the anchors. Sure, in most situations a single rapp would get you to the base of the cliff band. However, sometimes multiple rappels would be necessary; and suitable anchors may be scarce, especially on a talus slope above the next lower cliff band, or part way down a steep face. Getting stranded is a real possibilty.i'm having visions of a man prusikking a 6mm line using 2mm prussiks. maybe a wee dicey. probably a lot quicker, easier, less risky just to backtrack up a bit and find another line of descent. |
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I rappelled on 8mms the other month with a high friction device and I still wasn't too psyched on it. 8mm would probably fit the bill for ya, and go with a Petzl Reversino or similar device for small diameter ropes. |
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Mike- I've experimented with an ATC Guide with 7mm and 8mm ropes. It's hard to hold simply based on what you have to grab, but even the "guide" mode will still work, although if the 7mm slipped past itself, the device would fail...8mm is the smallest I would possibly go with any belay device. |
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7mm rap line with two carabiners in the ATC Guide for extra friction. Another couple lockers and loops of 4mm prussik cord. Carry some more 5mm for anchors and you should be O.K. |
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Thanks to all of you, Some really great ideas and advice, Yes absolutely will practice a lot with my kit [if I put together an acceptable kit that works] before I do it for real. I have been on top of a lot of cliffs and I cannot imagine getting stranded with either to short a rope or no anchors between them, As I can clearly see what is below and could measure the cliff with the rope first. But if it is to sketchy I would back tract and walk around. I am 50 and have been running around in rugged mountain terrain for more than half of that time. I have had some close calls so I know the difference between adventurous and foolish. My wife would say foolish but that is from an arm chair quarterback. None of you real mountaineers live your life by the "what ifs". You know that you should have enough fear to respect & prepare but not so much fear as to be controlled by it. Thanks to all of you again. bob |
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youtube.com/watch?v=6ulTTrh…
Use the monster munter shown above to rappel on maybe a 7mm line. It will provide plenty of friction. Then look up the biner block method. So you'll have 20-30m 7mil line and a super light pull cord. For a harness just buy a double length sling, wrap it around your waist (with ends in front), reach through your legs and grab one strand and pull it under and around to the front then attach all three bights with a locker. I bet you can do this all under 5 pounds. |
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bob kehn wrote: When I get to a cliff, loop around a tree, self belay down,What do you mean by self belay down? bob kehn wrote: pull my rope, gently,How will you do this? Gently? bob kehn wrote:what are the problems with my idea?You really need to pick up a text on this subject and educate yourself. I second the canyoneering website. Most climbers I know will settle for the easy walkoff over the sketchy rappel 99 times out of 100. Even if it means a little backtracking. I used to think of silly things just like this before I knew better. Go talk to the canyoneering guys before you kill yourself. |
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6mm Vs. 11mm |
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Mike J. wrote:6mm line has 138% less suffice area 318% less internal volume then 11mm cord!One cannot decrease a nonnegative quantity by more than 100%. The actual numbers are 45% (500/11, for the surface area) and 70% (8500/121, for the volume). |
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You all are over-thinking this, IMO. Some 4/5/6mm cord, a double/triple length runner (size dependent on your girth) with for a improvised harness and a locking biner are all that are really needed for this. No need for a belay/rap device... The Munter mentioned above should work fine, as would the Monster Munter. That said, I'd likely do a biner wrap as I find it easier to rig for this kind of thing and smoother should you have to pass knots for some reason. |
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Ive done 150' free rappels on a single 8mm strand with an ATC and friction was not an issue. |