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Chiloe
Trad climber
Lee, NH
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May 11, 2010 - 05:08pm PT
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Gene, there's less redundancy than it appears in your 3-biner rig!
Like rgold, I'm happy to use double ropes (8.8s) when I know we'll need 2 to get down.
JimE, being an ice climber, and brought twin 7.7s on our rock climb last fall.
That works too, they're dynamic so I guess you could lead on one if you had to,
and no tricks are needed to rappel.
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slobmonster
Trad climber
OAK (nee NH)
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May 11, 2010 - 05:11pm PT
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The illustration from Petzl is only that: an illustration.
It does indeed show one rope with a bight tied into its middle; it should not take you much imagination to conceive the same setup with two ropes tied together.
It's not a common technique for rock climbers to use as mode of descent, but rather more prevalent among cavers and canyoneering enthusiasts and the like. Translation: these people use the rope as a descent tool PRIMARILY, and not as a descent tool SECONDARILY (as we climbers do).
Utilized correctly, it allows for full-length rappels with the slight added weight of a skinny pull cord.
Now. Cleo, you *know* I'd roll my eyes so far back as to SEE BEHIND ME if you ever showed me such ATC shenanigan malarkey.
Some variations on a (perhaps) better ways (more controllable, more comfortable with a pack); as noted above you can add/duplicate the belay carabiner to add some more friction:
Redirect the brake strand, or
Extend device and redirect brake strand, or
Extend device and integrate an autoblock.
Euro-style belay/rappel sling, for extending effective belay loop.
Or if you have a plaquette device (ATC Guide, Reverso, and the like), this makes for a nice, smooth descent, and won't sharpen that pesky edge:
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phile
Trad climber
SF, CA
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May 11, 2010 - 05:22pm PT
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Seems like most people are talking about a prusik above the device vs. an autoblock below the device. Is there a reason for the two different friction knots in the different places?
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Mighty Hiker
climber
Vancouver, B.C.
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May 11, 2010 - 05:24pm PT
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Thank you - point taken. And Petzl is as much or more a supplier of caving as it is of climbing equipment. But climbers most often rappel with two ropes, given that rappels are typically more than 40 m. So a diagram showing that application is what's needed.
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HighTraverse
Trad climber
Bay Area
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May 11, 2010 - 06:13pm PT
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Hello MightyHiker
I take exception to this
In the spirit of RC.noob, climbingcook's knot is totally wrong. The loop of one bight should simply loop/catch the other - there's no need to make a reef knot of them. With this configuration there are two problems.
The strength of BOTH bights is reduced by the extremely small bend radius that can result under load. Both bights will deform into a 'pinch'. When the bight is over a biner the biner is limiting the minimum radius of the bight.
#2: with multiple rappels there may be significant chafing between the two bights. Something that all the "static" knots avoid.
Given the apparently good choices between double fisherman's and EKD, I'll have a look at but will be very sceptical of any other knot.
I posed a question earlier that hasn't been answered.
What's the best knot to put in the rope tails?
Best = won't pull through brake and won't untie itself in the wind.
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Mighty Hiker
climber
Vancouver, B.C.
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May 11, 2010 - 06:17pm PT
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Just joking - in the unlikely event that I used the EDK system, I'd use a Flemish bend to join the ropes, with ample tails and backup knots.
The EDK system as depicted seems an unnecessarily specialized and complex solution to a general situation.
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HighTraverse
Trad climber
Bay Area
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May 11, 2010 - 06:28pm PT
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cleo
Referencing your pic. Thanks for posting it as I was wondering how it was done.
I would be less worried about the internal rib breaking (OK, so I have too much faith in the aluminum).
I'd be more worried about excessive heat build up and stress on the rope due to the extremely tight radius around the center rib.
All the rope testing is done with a "meaningful" radius bight such as around a 'biner.
The stress in the fibers goes up as an inverse power of the radius. Heat and stress combined are what makes ropes fail.
I'm not dismissive of the need to rapp on a 7mm although I've never done it.
I'm over 200 lbs with clothing and a rack. Suppose the lead rope is lost/severely damaged, etc.
I've never gone out without at least 8mm ropes. The ATC Guide is specifically designed for this diameter.
If I had to rapp on 7mm I might add friction to the ATC with a Munter hitch around another locker on my harness. Simple and using all components in the way they were intended.
I don't use a GriGri or other device that requires moving parts for a variety of reasons. If I ever do, I'll carry an ATC for rappel. It weighs nearly nothing.
From this discussion I've become convinced that an autoblock knot is superior to a Prusik for descending. And possibly that I should use it every time.
Fred
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August West
Trad climber
Where the wind blows strange
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May 11, 2010 - 06:42pm PT
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I had a very unpleasant and somewhat dangerous rap experience when I had tied knots in the end of the ropes and one of the ends blew sideways and caught behind a flake. Caused me to stop putting knots in the end. I usually rap with the trango Jaws and the weight of the rope itself is usually enough to lock the device off (to work on tangles I wrap rope on leg).
An alternative rap method that I have played around with (although I have posted this before--and alas I couldn't find it--this looks like a good thread to bring the idea up again):
For a multi-rap descent with two raps (not a super skinny tag line) the ropes are ready to be pulled from the previous rap:
Pull the rope (rope A), feeding it through the anchor, and keep this rope bunched up at the belay. Rope B falls below you. Clip rope B straight to the anchor (figure 8 on bight/clove hitch with locking biner). Clip the end of rope A to the first climber (locking/clove hitch is fine since this is a backup). First climber raps rope B while second climber belays them (using rope A). First climber can rap using a cinch, only has one rope to deal with tangles, and doesn't need an autoblock backup/knots in the end of the rope since they are being belayed. When they get to the next anchor and have clipped in, Second climber unties Rope B from the anchor and can now do a normal two rope rap while being fireman belayed by first climber.
First climber is not being lowered, he can control his speed/stop whenever. Depending on the belay device and comfort level, a pretty skinny second rope could be used. I'm comfortable using a cinch on an 8.1, and with a belay from above there are plenty of setups where a 7mm static would be fine.
My partner and I have done this a few times. I think with practice it wouldn't slow you down much (especially if attachments are made with a clove hitch). The first down only having one rope to untangle makes up for some loss time and I carry a cinch on multi-pitch anyway (which makes for a nice rap of a single rope). Although I have not managed to make this my standard rap method--but reading the accidents reports might help me get there.
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the Fet
climber
Tu-Tok-A-Nu-La
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May 11, 2010 - 07:02pm PT
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I'd rather fall then be trapped on the wall and suffer a slow death, so I:
Use an EDK unless ropes are very different diameter, then I use a flemish bend / figure 8 follow through. The EDK is the least likely to get caught, I leave pleny of tail, no other knots. I like the name too. The flemish bend is much easier to untie than double fishermans.
I don't put knots in the ends when there's any chance they could blow to the side and get caught. I always watch the rope ends below me.
I use the autoblock below and often extend the belay device 12" above the belay loop. I like to be able to stop and rig the next anchor or take photos, or put on my headlamp/jacket with no worries.
As usual rgold's post was great, I will start using a fireman's belay for everyone but the first one down in case a rescue is needed.
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Clint Cummins
Trad climber
SF Bay area, CA
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May 11, 2010 - 07:13pm PT
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I don't like this example so much. Better to run the rope around behind your butt - more friction than a biner. I could see running the rope under your butt, then through a biner on the far side and down.
Plus, you should try not to create a situation where you have to lift and hold the rope up to add friction. It should be a downward motion of your arm. (Although technically when moving the rope under your butt, you are moving the rope weight to the side, and eventually lifting it on the far side of your butt).
Same principle is why it's risky to belay your follower from an ATC right on the anchors above you. You need to have an easy way to angle the braking side of the rope to create maximum friction in the ATC, and you need degrees of freedom to create any angle. Running the rope through the second biner in the photo above reduces your degrees of freedom greatly.
My personal rappel preferences for Yosemite are:
 Flemish bend / rewoven Figure Eight to join 8.1mm (dynamic) and 9.X/10.0 mm ropes
EDK profile not needed on Yosemite granite or Indian Creek; would be good in Dolomites and maybe Red Rocks
EDK prone to wear in a single spot and core shot the ropes. This happened while toproping one climb at Indian Creek. Figure Eight wears at random points on the surface of the knot.
short ends (about 3") with Figure Eight - less rope to cut off the end if it does get a core shot (I will compromise to slightly longer if my partner objects)
no "backup" knots
neat/tight knot
thread the 8.1mm through slings or rings/chains - easier to pull the fat one, easier to pull the 8.1mm out free from the wall, if the 8.1mm gets stuck you still have the lead line
put knot on the side where you expect to be pulling from, so ropes are not crossed
no knots in the ends, unless it's overhanging/dark and we can't see the next anchor point
remove tape from ends of rope - it increases risk of getting end stuck in a crack
ATC on locking biner on my belay loop for most rappels
Munter hitch on locking biner when rapping single strand 8.1mm
no "simulrap" - needless risk
a 5mm cord is the waistbelt for my chalk bag, for emergency prusking
a tiny knife on this cord, good for cleaning old slings from bolt anchors and cutting rope or hair/clothing if necessary
if I'm rebolting or on a wall, I have my jumars out and clipped to my belay loop, so I can stop anytime, pass knots, etc.
I've witnessed the following rappel incidents:
my joining knot stuck in a crack (Bugaboo Spire, 1974) Easy 4th class solo to free it.
rapped solo to a hanging station. Before pulling the ropes, I was fiddling with the anchor. I wasn't paying attention and let go of the ropes. They drifted over about 9' to my right, out of reach. I put a biner or Fifi hook on the end of my aiders and managed to snag them...
core shot to shared ropes with EDK on sandstone toprope mentioned above
my lead line hung up on rappel down NE Face of S Howser, because we didn't pull the rope out clear of the face - wall above not climbable without pitons; we had to cut off 30m
party above us simulrapping down to Sons of Yesterday belay tree - one of their knotted rope ends hung up in the crack well below the belay tree. This made it impossible to pull their rope, unless they got the knot out of the crack, but they did not have enough rope to belay down there, unless they climbed partway up the pitch above to free rope. Fortunately my partner was climbing up to it and freed it for them.
partner's taped rope end stuck in a crack (Middle Cathedral, rappel above Turret - forced bivvy and climbed up to free it in the morning)
very end of my 9mm rope hung up on pointed side of lap link on Harry Daley rappel, because I was lazy and did not deal with slipped sheath which exposed loop in core strands to melted rope end. Reclimbed pitch to free it. Remelted rope end when I got home.
once while solo aiding, I set up an intermediate anchor to rap down and backclean some gear. After playing with some gear, I went to weight the ATC and it popped off the rope - I had put the loops through the ATC but had not clipped them into the locking biner. Fortunately I caught myself on my "guide hand" and batmanned back to the anchor. It was a case of getting too casual - not checking myself at each step. It also shows the risk of doing something partway and stopping, like tying half your knot - it looks right later but is deadly.
I was cleaning a climb on a 2 rope rappel when it was finally time to leave. I headed down the ropes, noting a clump in the 7mm partway down. I figured it was the usual tangle. When I got down close to it, I realized I had hit the rope with a loose flake earlier and the bits were cut and melted together. I did not have my jumars out. The first task was to batman up enough to get enough rope below me so that I could tie off the rope on my thigh, and get a knot on it above the bad part. It was steep, and I had weight in a pack, so this was strenuous. Next I had to put makeshift prusiks with slings on both ropes (around both strands might have been better). The ropes went through big lap links, so they slipped back and forth very easily. Much seesaw prusiking and eventually strenuous batmanning ensued, mostly to save time. Then I had to rerig for a couple of single line raps on the lead line.
my rappel rope hung up on the side of a dirt hummock while cleaning "Gardening at Night" above the Church Bowl. Too much friction on dirt to pull it. Did not have adequate gear/strength to prusik up rope. (Did prusik up 100' with 1" webbing, but it was very slow and I was cramping). Result: I was rescued by Bill Russell and my partner. Made it into Accidents in North American Mountaineering. Could have been prevented if I tested the rope pull while only 30' down the rope, or by having prusiks.
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slobmonster
Trad climber
OAK (nee NH)
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May 11, 2010 - 07:24pm PT
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Clint, I actually agree with you; only showing variations on a theme.
If anyone cares (they don't) I most often abseil with a plaquette device rigged as my photo above, with the brake strand(s) passed under my right thigh. I hold them in my hand on the lateral side.
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Seamstress
Trad climber
Yacolt, WA
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May 11, 2010 - 07:58pm PT
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We have had "rope rescue" missions from the rap rope getting stuck with or without knots tied in the ends. If the wind is blowing or the route looks like a rope eating zone, then take the rope with you and pay it out as you go. It can go into stuff sack, be carried in coils, ....good technique for a final rap above water. Yes, it is slower than tossing the line - unless the line gets stuck. We only need to do this a few times a year.
My husband uses a sling to extend his rap device. That adds friction. I do that occasionally. On low angle slabs, I don't - it is too much friction. The bungeeing effect is a lot of work and can be dangerous if there are any sharp edges. When we use that technique, we usually use two short runners rather than one long one. Is that redundanitis? Yes.
As stated before, have a ritualistic standard. Then assess the situation and adjust if necessary. Adjust consciously.
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Manjusri
climber
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May 11, 2010 - 09:06pm PT
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Phile: "Seems like most people are talking about a prusik above the device vs. an autoblock below the device. Is there a reason for the two different friction knots in the different places?
If you play with the autoblock you'll quickly see why you wouldn't use it above the device. It doesn't create as much friction on the rope as the prussik or kleimheist. It isn't suitable for hanging directly on or ascending.
This also makes it easier to use below the device where it functions like an extra brake hand, using the friction of the belay device to stop the rappel. It glides along the rope easier than a prussik though I have seen someone using a prussik below the device. I typically use a runner for my autoblock (when I use one) for the same reason.
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Jay Wood
Trad climber
Fairfax, CA
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May 11, 2010 - 09:46pm PT
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Toproping aside, one of the merits of the EDK is that the knot rides away from the rock- less prone to wearing through the sheath. This is also the main point, in case you missed it- the knot is less likely to hang up because it rides away from the wall.
Re using fireman's belay (good practice) only because an unconscious climber would be stuck up there:
It's hard to imagine when you would lower that person herky-jerky, or more probably- bump and bang over rocks, especially not knowing the injuries. So more likely you would ascend the ropes to assist, making the rappel back-up a benefit to the situation.
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Clint Cummins
Trad climber
SF Bay area, CA
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May 11, 2010 - 10:38pm PT
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> one of the merits of the EDK is that the knot rides away from the rock- less prone to wearing through the sheath.
Actually, I believe it's the opposite. The EDK concentrates wear on the 2 strands where they emerge from the knot and bend at 90 degrees.
The rewoven Figure Eight puts wear at random points on the surface of the knot.
I agree, though, that toproping/lowering will probably wear the rope a lot more than pulling a rappel.
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bmacd
climber
Relic Hominid
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May 11, 2010 - 11:40pm PT
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The recurring flaw here, is the folks using belay devices for rappels. Someone died using a Cinch.
I am with Werner, always used figure 8 device or a set of ovals, shipoopi's advice is also very good
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Jay Wood
Trad climber
Fairfax, CA
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May 12, 2010 - 12:59am PT
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Huh.
I'll check that out.
Of course, the figure eight is more likely to cause the severest wear- chopping the stuck rope!
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Dr.Sprock
Boulder climber
Sprocketville
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May 12, 2010 - 01:05am PT
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anybody use the reverso 3 in autobrake mode?
note that the fig. 8 knot is safe when used to tie a rope to the harness,
as it is being pulled from 3 of 4 leads.
we need a scuba diving white 3 by 5 message card with grease pencil boxes for checking off every rap,
both people, military style for absolute safety when totally fried.
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WBraun
climber
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May 12, 2010 - 01:31am PT
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Let's see ...
The original mistake was forgotten biner.
Then everyone runs amok in this thread going every which way how to rappel.
Good grief ....
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