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rgold
Trad climber
Poughkeepsie, NY
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May 17, 2010 - 09:37pm PT
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PTPP wrote: "Can the EDK be used to join two ropes of dissimilar diameter? My understanding is that it cannot.
I don't think there have been conclusive tests, but as far as the rolling failure mode is concerned, I believe that a properly tied EDK with different diameter ropes is actually more secure than one tied with equal diameter ropes, because the larger rope can be situated so as to inhibit rolling.
What I mean by "properly tied" is illustrated with two photos in a post on in the thread started in a vain attempt to avoid technical discussions here. The part about EDK's is at the bottom of the post.
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k-man
Gym climber
SCruz
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May 17, 2010 - 10:31pm PT
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I haven't gone through the whole discussion here, but in reference to rapping with one skinny and one fat rope: I always like the 2nd rope to be fat enough so I'm comfortable threading that though the anchor when rapping.
I learned once that it's best to pull your lead line down, not the skinny 2nd line. That way if things go haywire, you have the lead line in hand and not your dental floss.
I think Werner states this upthread too: how he uses a 7 mil and pulls fat.
Just 2 more c.
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rockermike
Trad climber
Berkeley
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May 17, 2010 - 10:42pm PT
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7 mm and 6 mm are two different animals. Personally I will thread a 7 mm at times although I consider it dangerous. But its fast - particularly on multiple rappels where each pull is on a different line (assuming you are pre-threading the rings before each pull). I still think tying off the 7 mm below, before the second raps is worthwhile safety. With a 6 mm there is no way you can rap with the skinny threaded through the rings.
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danimal7777
Trad climber
Crystal Lake, IL
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May 17, 2010 - 11:11pm PT
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I am very, very sorry for this loss.
I can't believe out of a couple hundred posts, no one has mentioned the need for a blocking washer to prevent a knot from pulling through a rap ring or a mallion or screw link.
It is the only absolutely safe way I know of to prevent extrusion of a knot. "On Rope" documents it, and not that long ago a caver was killed because his partner left the washer out of the assembly. He indicated (in summary) that they got away without it for decades, and didn't figure it mattered.
I would only bet my life if there was a washer to stop a knot, and have bet my life on that arrangement. Not being from the Yosemite scene, I guess it's not a local custom to use it. I always carry one washer for each rap ring.
Very many regrets.
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Esparza
Trad climber
Westminster, CA
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May 17, 2010 - 11:25pm PT
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Wow... I have not logged on in a while and noticed this post.... My deepest condolences to all left behind. Safe travels to all.
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'Pass the Pitons' Pete
Big Wall climber
like Ontario, Canada, eh?
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May 17, 2010 - 11:33pm PT
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Not familiar with the washer. At any rate, any other system except the one described in the Petzl catalogue will GET YOU KILLED.
Are you wankers paying attention? Quit reinventing the wheel for fvck's sake!
"It seems to me that the EDK is a poor choice for a knot-block system. The great advantage of this knot is that it is flat on one side, so that it has a smaller chance of getting stuck on things: exactly what you DON'T want if you are relying on the knot getting stuck on the rappel ring. I have not done any testing to prove that a follow-through figure-8 or a double-fisherman's would not pop through a gigantic ring when weighted, but it seems much less likely to happen than with an EDK or any knot with a "flat" side.
Comments?"
Look, did you guys read my post, or knott? There is NO SUCH thing as a "knot block system"!
Look, do you "get it", or not? If you "get it", you will live. If you don't "get it", you will die.
IF YOU DO NOT GET IT, PLEASE COMMENT HERE AND I WILL DO MY BEST TO KEEP YOU ALIVE.
There is only ONE SAFE WAY to do this, and that is to put your rappelling rope through the anchor, then tie a butterfly knot in one end of it, and CLIP THIS KNOT TO THE OTHER SIDE WITH A LOCKING CARABINER.
It doesn't matter how you attach your pulldown rope to the end of your rappel rope! Use an EDK, a figure of 8, a couple overhand knots with a couple lockers, hell, use a fvickin' rubber band. Even if the knot joining the pulldown rope to the rappel rope fails when you go to pull it, you can jug back up your rappel rope and re-do it! Why? BECAUSE you secured properly secured the rappel rope. It is not a big deal to pull down a locker plus butterfly knot.
Buddy DIED because he TRIED TO REINVENT THE WHEEL.
Read the bloody catalogue. PAY ATTENTION. Learn, and live.
I'm with Dave Kerr. BITD when I used to free climb, I used double ropes exclusively. A far superior system in so many respects.
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TripL7
Trad climber
san diego
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May 17, 2010 - 11:43pm PT
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I agree, double ropes is the way to go!
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Dr.Sprock
Boulder climber
Sprocketville
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May 17, 2010 - 11:51pm PT
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Thank's PT Piton Pete and The French Guy!
finally the correct answer.
i was wondering about that.
because if the knot slips thru the anchor, your skinny rope backup will work, but now you are hanging from a loop in the skinny rope, which is hanging from the belay ring.
and if you shock this now compromised system, you are really asking a lot of the pull down line.
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'Pass the Pitons' Pete
Big Wall climber
like Ontario, Canada, eh?
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May 18, 2010 - 12:37am PT
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Doc,
I answered the question correctly several pages previously. Some read and got it, some didn't.
Those who didn't, well, we'll pick up their bodies at the bottom of the crag.
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Clint Cummins
Trad climber
SF Bay area, CA
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May 18, 2010 - 12:58am PT
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The "pull cord" system makes a special assumption that correctly sized rings exist at every rappel station you will use, or that you have enough correctly sized quicklinks/rings with you to equip all stations.
Equivalent to what danimal7777 wrote, when you have a tiny pull cord, you are relying on the knot to be larger than the rings at all anchors. So you need to bring enough quick links or rings to equip any/all anchors where you will be rappelling (or you could have a special washer to essentially enlarge your knot). The weight of the spare quicklinks might negate the advantage of the light pull cord. Of course, if you are rappeling down the same anchors where you climbed up, you can inspect as you go up and just downclimb or leave gear if you don't have the links you need, or if expected belay bolts/anchors are missing, etc.
Also, the biner and butterfly loop are not as "low profile" as the EDK, so the system might have a higher risk of hangup. Any knot can hang up in a crack, but with a ring/knot blocking system, you do not have the option of advancing the knot down below cracks/objects in the vicinity of the anchor.
If you could somehow guarantee that rings were in place at all anchors, this still does not insure their inside diameter is appropriate, so you have to be able to tie a much larger version of your blocking knot or bring a blocking washer, to make sure your knot/washer can't pass through the existing rings.
The blocking knot/locking biner setup does not work well for plain slings, as the knot could pass through the slings. You would then be held by the locking biner, but you might not be able to pull the knot back through the slings. A (properly sized) ring/quicklink is required for the "pull cord" system.
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Fish_Products
Big Wall climber
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May 18, 2010 - 01:10am PT
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Maybe I missed some of this during my quick scan.... but how about you bring no extra gear and use what you have? This method with the cloved biner, either clipped to the rap line or not, will never go through the rap rings. You can use parachute cord for the pull if you want to keep it ultralight.
The problem with the other "safe" methods is if the knot goes through the rings you are screwed and will probably have to shimmy the cord to get back up to the anchor to fix the problem.
Edit: I think I like it in the unclipped mode so I can pull the trailer from a more obtuse angle if needed when retrieving.
See us on the web at:
http://www.FishProducts.com
http://fishproductsblog.blogspot.com/
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Dr.Sprock
Boulder climber
Sprocketville
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May 18, 2010 - 01:25am PT
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you really need a locking biner, if that gate opens, loose cheese.
especially with the blockin knot, as when it pulls thru the rap ring, it will be sitting agianst the gate of the biner, trying to pry it open.
and a biner was not designed to be loaded from the outside, no?
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Fish_Products
Big Wall climber
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May 18, 2010 - 01:28am PT
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Dr.Sprock: you really need a locking biner, if that gate opens, loose cheese.
especially with the blockin knot, as when it pulls thru the rap ring, it will be sitting agianst the gate of the biner, trying to pry it open.
Why do you "really" need a locker? Truth be told, in this set up I would rap without a gate on the biner. The knot can never go through the rap ring. The gate never comes into play. Prove me wrong.
See us on the web at:
http://www.FishProducts.com
http://fishproductsblog.blogspot.com/
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WBraun
climber
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May 18, 2010 - 01:30am PT
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Why?
Because locker has what Dr.Sprock smokes in his bowl .....
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Dr.Sprock
Boulder climber
Sprocketville
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May 18, 2010 - 01:30am PT
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1) the clove hitch is not a very secure not, it is designed to move and un ravel,
2) for that warm fuzzy feeling when your hangin,
3) if they use a blocking knot and it pulls, it is now resting on the biner gate from the outside (try it with some practice rope)
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Fish_Products
Big Wall climber
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May 18, 2010 - 01:32am PT
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Dr.Sprock: 1) the clove hitch is not a very secure not, it is designed to move and un ravel,
Not true. Do you have a cite? Even if the clove moved (designed to ????) it moves to tighten, not some random orbit that is going to rifle through your anchor point.
Have you tested the clove in any drop tests? Have you measured the creep on clove hitches while under load?
Dr.Sprock: 3) if they use a blocking knot and it pulls, it is now resting on the biner gate from the outside (try it with some practice rope)
What are you talking about? If it pulls? How does "it" pull exactly? How does that knot get to the gate?
See us on the web at:
http://www.FishProducts.com
http://fishproductsblog.blogspot.com/
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'Pass the Pitons' Pete
Big Wall climber
like Ontario, Canada, eh?
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May 18, 2010 - 01:34am PT
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My fvcking gosh YES! You need a locking crab!
"If you could somehow guarantee that rings were in place at all anchors, this still does not insure their inside diameter is appropriate, so you have to be able to tie a much larger version of your blocking knot or bring a blocking washer, to make sure your knot/washer can't pass through the existing rings.
The blocking knot/locking biner setup does not work well for plain slings, as the knot could pass through the slings. You would then be held by the locking biner, but you might not be able to pull the knot back through the slings. A (properly sized) ring/quicklink is required for the "pull cord" system."
Clint - normally a voice of reason on this forum - do you have any idea WTF you are talking about???
This system has NOTHING to do with washers, and has NOTHING to do with the size of the rappel anchor. And it has nothing to do with a "blocking knot". Rig it as Russ and the Petzl catalogue has shown. Use slings, carabiners you hate, whatever, it matters knott. It has to do with tying the knot that Russ shows.
I prefer using an alpine butterfly to the clove hitch Russ shows, but either will work - with a locker. [Would you trust your life to a single non-locking crab? I sure as hell wouldn't]
Russ is right - parachute cord, or spaghetti, will work as your pulldown cord.
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Dr.Sprock
Boulder climber
Sprocketville
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May 18, 2010 - 01:35am PT
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i just tied a clove to a biner, and it almost untied itself.
if the guy on rap takes a load off the rope, the knot could loosen and fall onto the gate.
if you need pics of what i am talking about, let me know.
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Mighty Hiker
climber
Vancouver, B.C.
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May 18, 2010 - 01:35am PT
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One potential problem with the EDK system is the whole shebang getting crammed into the rappel rings or slings or whatever, and jamming. It's designed to pull very hard on one side, so that everything slides and is against the anchors. All the various knots and loops and tails and carabiners, combined with whatever's at the anchor, creates potential for stuck ropes.
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'Pass the Pitons' Pete
Big Wall climber
like Ontario, Canada, eh?
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May 18, 2010 - 01:36am PT
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Uh, hel - LOW - hoe!
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