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weird question about self belay

Original Post
bob kehn · · Unknown Hometown · Joined Jan 2011 · Points: 0

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

Bill M · · Fort Collins, CO · Joined Jun 2010 · Points: 317

I think a canyoneering site would be right up your alley.

Brendan Blanchard · · Boulder, CO · Joined Oct 2010 · Points: 590

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.

Threading a rope around a tree also isn't a good idea, that would eat through a sheath in only a couple of raps if you're doing it like I think.

Disregarding all above info....any ATC, Reverso, Figure - 8, etc would work. However a figure-8 wouldn't provide a lot of friction with a small diameter rope.

Overall I would say if hiking is your thing, then do it and enjoy it. If you want to get into climbing, canyoneering, spelunking etc...then do that.

Wyatt H · · Unknown Hometown · Joined Oct 2010 · Points: 6

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.

BigMoveMike Jacques · · prescott · Joined Oct 2009 · Points: 65

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.

For your application I would look for a light weight Canyoneering rope that is designed for rappelling. blue water makes some really nice static lines.

bluewaterropes.com/ look at the 8mm CANYON XTREME. It weighs about 4lbs 10oz for 50 meters(150 ft)

Any one els out there have any advice on good belay/rapp devices for 8mm ropes? ATC guide?

Kent Pease · · Littleton, CO · Joined Feb 2006 · Points: 1,066

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.

Peter Stokes · · Them Thar Hills · Joined Apr 2009 · Points: 150

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?

slim · · Unknown Hometown · Joined Dec 2004 · Points: 1,103
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.
Sam Stephens · · PORTLAND, OR · Joined Jan 2010 · Points: 1,090

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.

I'll second the caving/canyoneering books as a good resource.

Brendan Blanchard · · Boulder, CO · Joined Oct 2010 · Points: 590

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.

As said above, prussik may be a little difficult (understatement) on a <9mm line. And I doubt you would sink money into ascenders as a backup to hiking, if they even support the smaller diameters.

And by far the most important piece of info, is get proper instruction. Rappelling isn't something you can just pick up as a side hobby, you REALLY need to know what you're doing, your life is on the line...literally.

Bud Martin · · Bozeman, MT · Joined Apr 2010 · Points: 380

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.

But really seek some instruction or at least buy a book and practice on a short cliff with easy access/anchors.

bob kehn · · Unknown Hometown · Joined Jan 2011 · Points: 0

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

Tosch Roy · · Bend · Joined Nov 2010 · Points: 45
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.
Yarp · · Unknown Hometown · Joined Jan 2011 · Points: 0
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.
BigMoveMike Jacques · · prescott · Joined Oct 2009 · Points: 65

6mm Vs. 11mm

6mm line has 45% less suffice area 70% less internal volume then 11mm cord! what does that mean? more heat transfered threw a smaller surface area being absorbed by a much smaller mass.

I have double rope rappelled from the third bolt of a sport route,(backed up by a top rope)about 25ft on 5mm cord using a double munter. The rappell was very hard to control and got hot enough to glaze the sheath of the cord. The carabiner was about as hot as you would expect from a FAST 150ft rappel on double ropes.

There is a reason none of the climbing rope companies are marketing a 6mm or 7mm static line. even though there are 5mm cords rated to 5000lbs.

EDIT: for bad late night math skills( thanks for the correction Brenta)

brenta · · Boulder, CO · Joined Feb 2006 · Points: 75
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).
Aric Datesman · · Unknown Hometown · Joined Sep 2008 · Points: 145

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.

As a point of reference, this setup worked just fine for me doing a freehanging rap on a pair of core strands from a 10.something dynamic line (actually it was a 30' rap on the core strands from 5' of line knotted together). Five wraps around the spine of the biner gave plenty of friction and was easy to control and lock off. Keep in mind that bodyweight was right at the limit of what those strands could handle strength-wise, so stepping up to 4/5/6mm would be a good idea in terms of strength and abrasion resistance.

Oh, and I should probably add that backtracking is likely the best way to go. Far less chance of screwing something up or gear failure. Plus skinny lines don't pull all that easily and get tangled/stuck very easily, so most likely going around would be far less hassle.

Tom Grummon · · Salt Lake City, UT · Joined Oct 2009 · Points: 30

Ive done 150' free rappels on a single 8mm strand with an ATC and friction was not an issue.

Guideline #1: Don't be a jerk.

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