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tisar
Jun 16, 2005, 12:36 PM
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Knotted cord as pro
This is a specialty of certain areas in Europe, namely in the Saxon (Germany) and Czech Sandstone (Elbsandstein). Though the topic arises frequently and the one or the other might add something to her/his own bag of tricks.
In the mentioned areas every use of metal as pro is prohibited to save the extremely soft stone from further impact. Indeed the rock is so soft, placements of cams, nuts or hexes would be very likely to blow the rock itself.
As a substitute climbers always have been using and still use strands of cord, knotted and placed like chocks. Different diameters of cord and different knots give a good variety of placements for different crack sizes.
Typical placements in the Saxon Sandstone:
http://www.gipfelbuch.de/..._knotenschlinge2.jpgknot sling
http://www.gipfelbuch.de/.../sanduhrschlinge.jpgslung hourglass
A normal ‘rack’ for the Elbsandstein might contain cord of diameters from 4mm (Kevlar) to 12mm or higher, a good amount of tubular webbing to sling rocks and hourglasses (washed out columns in the rock) and some special webbing called ‘Fusselschlinge’. The later are slings of a very fuzzy webbing which sticks to the sandstone quite well and keeps them in place.
Chocks of cord? Sounds sketchy and so I was very skeptic when I booked that leading class in Saxony. I knew that climbing (and hard climbing too, 5.1x’s have already been send around the 1930’s – barefoot!) has been done in Saxony since the early 19th century and the technique of knot slings is well established, but still… Now I’ve seen it first hand, I’m pretty impressed. The right cracks given, bomber placements are possible! In fact, I might trust a good knot more than a nut in the same place – at least in this kind of rock.
Why? Sandstone provides a very high friction. After flattening a knot (Figure-of-Eight, double-stranded is the most reliable, see link below) and placing it, a good tug will produce a certain camming effect. In constricting, the knot expands, filling the crack as far as possible and nestling itself to the rock. The contact of knot and rock is maximized and the force is spread over a great surface, minimizing the impact on the rock and preventing blow outs. Thanks to the friction, in shallow cracks the knot is likely to keep in place and even almost parallel cracks might allow a placement.
Now what forces does a placement like this withstand? Check this link to find a test on knot slings by Jörg Brutscher (Thanks to j_ung for correcting my bad English!).
I'd strongly recommend to try it once. It might be a good alternative to 'the one nut that doesn't fit perfectly'. If not it's still fun...
Climb on!
- Daniel
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cruxmonger
Jun 16, 2005, 1:55 PM
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Very interesting. I'm not sure that I am going to throw my rack in the garbage, but interesting nonetheless.
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kimmyt
Jun 16, 2005, 2:07 PM
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Yeah, but how hard is it to clean one of those suckers??
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tallnik
Jun 16, 2005, 2:11 PM
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I love the fact that there are 5.1X rated routes there.
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tisar
Jun 16, 2005, 2:20 PM
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In reply to: In reply to: Yeah, but how hard is it to clean one of those suckers?? That's a good question. I know how easy it is to get a tangled rope hopelessly caught in a crack. I assume that if the wrong knotted cord caught the right fall, it would become a resident. Tisar, am I wrong?
First of all the leader should leave ends long enough and place them outside the crack for the follower to grap them (see picture). If not, those bummers will probably never come out.
As I avoided falling on one (just why?) I've no first hand knowledge concerning removal after a whipper. But with a nut tool kind of wooden stick it's (not too) easy to get knots out after having them weighted with body weight.
At some places I've seen abandoned slings but I don't know if they were just used to bail out.
- Daniel
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flawrence
Jun 16, 2005, 2:24 PM
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I've used knotted webbing as a retreat anchor in a crack rather than leaving gear.
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veganboyjosh
Jun 16, 2005, 3:05 PM
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how big a role do different knots play in this scheme? or is the size of webbing/cord the first determining factor in which "piece" of pro to place?
are different knots better for different cracks? or is it mostly overhand and water knots, and then the cor size adjusted based on frature size?
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oldrnotboldr
Jun 16, 2005, 4:25 PM
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Likewise, I have used one to rappel from but not as primary pro. Mt concern is the amount of abrasion the cord or sling would take, even without a fall.
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paulraphael
Jun 16, 2005, 4:33 PM
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Sorry, not familiar with an FoE ... what are some other names for this knot?
Is webbing ever used?
I'm definitely intrigued by this idea for rap anchors, but am hesitant to reinvent the wheel and use myself as a guinee pig. Would be nice to know how strong these knots test in good placements, and also how intuitive it is get a good placement. I wonder if it takes much more skill than placing a nut.
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j_ung
Jun 16, 2005, 4:45 PM
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In reply to: Sorry, not familiar with an FoE ... what are some other names for this knot? Is webbing ever used? I'm definitely intrigued by this idea for rap anchors, but am hesitant to reinvent the wheel and use myself as a guinee pig. Would be nice to know how strong these knots test in good placements, and also how intuitive it is get a good placement. I wonder if it takes much more skill than placing a nut.
FoE = Figure 8 (Figure of Eight)
Check the link in the OP. The tests described there may be just what you're looking for. :)
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socalbolter
Jun 16, 2005, 4:49 PM
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FOE = Figure of Eight
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thinric
Jun 16, 2005, 5:11 PM
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I have also rappeled off of 1" tubular webbing with the water knot jammed in a sandstone crack. I gave it a few good jerks with a hammer and found it to be rock solid.
Todd
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solo
Jun 16, 2005, 5:17 PM
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In reply to: In reply to: Yeah, but how hard is it to clean one of those suckers?? That's a good question. I know how easy it is to get a tangled rope hopelessly caught in a crack. I assume that if the wrong knotted cord caught the right fall, it would become a resident. Tisar, am I wrong?
It would also depend on the type of placement. I have fallen on a knot (11 mm cord) in a good nest and it was not stuck at all. On the other hand I've had knots placed by the leader which I had hard time getting out although they were not even weighted.
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bluenose
Jun 21, 2005, 10:30 PM
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This is interesting.
Not that I have any experience in trad (I am going to have to do something about this, I'm getting tired of stating that I have no experiece before posting :( ) but I would think that a knot could be better than a metal piece in a lot of situations. Just the higher resting friction (stay puttidness) than a metal piece has.
I read the initial link. The only flaw in starting to use this type of pro might be that nobody currently uses it in most areas, so it would be hard to learn the easy way.
Don't throw your rack out but for some just starting it would make sense to set up some for those gaps in the rack. Weight is probably similar but they would be awfully bulky, I would think.
Hmmm...enough brain farting from me.
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