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rgold
Trad climber
Poughkeepsie, NY
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Sep 16, 2014 - 07:56pm PT
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If BG thought like you, he wouldn't be responding to those questionably qualified people, whose stupid questions and never-endingly ignorant statements provide fodder for his responses. The effect, as you say, is that you learn something, which wouldn't have happened if all us idiots hadn't weighed in to give BG the chance to set everything straight.
So maybe you need to rethink some of your scorn, or failing that, refrain from posting just to say you aren't reading any of the thread you just posted to.
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climbski2
Mountain climber
Anchorage AK, Reno NV
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Sep 16, 2014 - 08:19pm PT
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Is ok.. I deserved that comment. rgold you are no idiot either..lol.. but you knew that.
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donini
Trad climber
Ouray, Colorado
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Sep 16, 2014 - 08:19pm PT
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I'm somewhere in between. I believe that there have been excellent responses from well qualified people. I also believe that we are beating a dead horse. Yo dudes.....setting up safe anchors from two bolt anchors is not something that requires diagrams, formulas, force vectors and the like.....it's easy and pretty f*#king hard to screw up.
I am forever mystyfied at why it takes people today so f*#king long to set up belay anchors on multi pitch climbs. Speed and efficiency on long climbs is a saftey factor that seems to be ignored.
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donini
Trad climber
Ouray, Colorado
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Sep 16, 2014 - 08:22pm PT
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Yikes!
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Scrubber
climber
Straight outta Squampton
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Sep 16, 2014 - 09:09pm PT
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As ridiculous as this thread is getting, I feel I need to speak to one recurring myth/ error. Repeatedly, 7mm cord for a cordalette is stated to only have a strength of 10-13kN, versus a sewn sling of around 22kN. This lower strength is the cord's tensile strength. As in, single strand. Once it's tied into a loop, the strength is double, as it is shared by two stands, then take away about 1/3 for the knot. (13x2)x.67= 17.3kN
When you use cord in an equalized and tied off at the focal point two bolt anchor with a single loop going to each bolt your strength would be (13x4)x.67= 34.6kN
If you rigged something like the one shown several posts ago with two loops of cord going to each bolt you get a whopping (13x8)x.67=69.3kN
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BG
Trad climber
JTree & Idyllwild
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Sep 16, 2014 - 09:37pm PT
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I am forever mystyfied at why it takes people today so f*#king long to set up belay anchors on multi pitch climbs. Speed and efficiency on long climbs is a saftey factor that seems to be ignored.
My experience is that people take so long because they haven't learned how, when, and where they can trim the fat with anchor building.
I concur. There is usually no need to get fancy. In 30 years of guiding multi-pitch routes at Tahquitz, 90% of the time it's as easy as place 3 bomber pieces, pre-equalize with a cordellette, and I'm done. I shoot for a master point at waist to chest level and use a direct belay.
In guides' courses I teach the same thing when it comes to anchors: keep it simple, especially with TR anchors. If the vector is one direction, there isn't much to gain with complicated self-equalizing systems. AS JL always said, the key is sound primary placements.
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JimT
climber
Munich
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Sep 17, 2014 - 12:32am PT
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A question for the engineers out there, that I've often pondered: If Dyneema is static material, by adding nylon to it (like a Dyneema/nylon blend sling, or a Dyneema core/nylon sheath cord) isn't the combination still essentially static? Like a rubber-coated wire cable?
A problem is there are various ways slings are woven, in a lot of the very thin slings the nylon is merely there to hold the Dyneema together. The ones with coloured edges and basically white in the middles are like this. The more normally woven hybrid slings you can actually see the Dyneema cut through the nylon threads when you tensile test them which I guess why they got rid of them.
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GDavis
Social climber
SOL CAL
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Sep 17, 2014 - 12:38am PT
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Sliding X with 1 single sling - Not Ideal (IMO) and should tie limiter knots (again IMO).
Sliding X with 2 slings - Ideal in most situations.
Call it old-fashioned, but I have a weird rule I try to follow: I should be able to slice any single strand of my anchor at any point without failure. The single sling fails that, however a second one is the best of both worlds.
The cool cordalette style is great but a bit bulky - I prefer 12-15' of 6 mil and rely on extra shoulder slings/etc in the odd event I'm equalizing gear not nearby (or even the rope).
Am I gonna die?
Thanks to Gaines for his input, I took his How To Rock Climb (3rd) out to Dixon Lake with my brother when we were in high school and I was WELL equipped to learn and explore anchoring - a great tool and one I've sold to dozens and dozens of climbers at Nomad!
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Tvash
climber
Seattle
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Sep 17, 2014 - 12:59am PT
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good stuff. thanks for all the testing etc.
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Delhi Dog
climber
Good Question...
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Sep 17, 2014 - 03:40am PT
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climbski2 writes:
Now that BG has chimed in I guess I'll read some of the thread. His stuff. It's not that I dislike great anchors.. it's that I dislike the endless conversations with questionably qualified people about them.
There is always more to learn when BG starts talking. rgold write:
If BG thought like you, he wouldn't be responding to those questionably qualified people, whose stupid questions and never-endingly ignorant statements provide fodder for his responses. The effect, as you say, is that you learn something, which wouldn't have happened if all us idiots hadn't weighed in to give BG the chance to set everything straight.
So maybe you need to rethink some of your scorn, or failing that, refrain from posting just to say you aren't reading any of the thread you just posted to.
climbski2 responds:
Is ok.. I deserved that comment. rgold you are no idiot either..lol.. but you knew that.
I just want to say that it is refreshing to hear a bit of smack talk and no one really getting their panties in a twist like so many do around here. It ain't that hard now is it?
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BG
Trad climber
JTree & Idyllwild
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Sep 17, 2014 - 10:44am PT
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A problem is there are various ways slings are woven, in a lot of the very thin slings the nylon is merely there to hold the Dyneema together. The ones with coloured edges and basically white in the middles are like this. The more normally woven hybrid slings you can actually see the Dyneema cut through the nylon threads when you tensile test them which I guess why they got rid of them.
JimT;
So when you tensile test a Dyneema/nylon hybrid sling does the nylon add any elasticity? Or is the elasticity of the Dyneema based soley on the weave pattern, adding a modicum of stretch to an essentially static material? Does pure Dynemma (in a short sling or cord length) have ANY elasticity at all (say 1-2%) at mbs?
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j-tree
Big Wall climber
Typewriters and Ledges
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Sep 17, 2014 - 10:48am PT
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climbski2
Sep 16, 2014 - 08:19pm PT
Is ok.. I deserved that comment. rgold you are no idiot either..lol.. but you knew that.
Very classy.
Delhi Dog
Sep 17, 2014 - 03:40am PT
I just want to say that it is refreshing to hear a bit of smack talk and no one really getting their panties in a twist like so many do around here. It ain't that hard now is it?
+1
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Tvash
climber
Seattle
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Sep 17, 2014 - 02:14pm PT
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"Repeatedly, 7mm cord for a cordalette is stated to only have a strength of 10-13kN, versus a sewn sling of around 22kN. This lower strength is the cord's tensile strength. As in, single strand. Once it's tied into a loop, the strength is double, as it is shared by two stands, then take away about 1/3 for the knot. (13x2)x.67= 17.3kN"
Mammut tested a 13kN 7mm cordelet and found that it broke at the anchor point (biner) at about 17 kN. Knot factor didn't figure in - in that it didn't break at the knot (double fishermens). Empirically, therefore, they found the strength of the doubled 7mm cord to be 1.35x, not 2x. Compound this ratio accordingly.
Comparatively, a 22 kN sling doubled should yield a breaking strength of at least 29 kN, using the same ratio.
http://www.highinfatuation.com/blog/cordelette-for-climbing-what-are-the-issues/
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Tvash
climber
Seattle
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Sep 17, 2014 - 02:30pm PT
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Regarding nylon versus dyneema runners - the problem isn't really a difference in melting point (unless you're pulling a rap rope directly through a dyneema sling - don't do that), but elasticity.
DMM tested 120 cm x 11mm (22 kN) dyneema versus 16 mm (12 kN) nylon sewn runners with F1 and F2 falls, knotted (overhand - a figure 8 is slightly gentler though) and not knotted.
The dyneema's strength remained nearly double that of nylon when not knotted but was about equal to nylon when knotted.
http://dmmclimbing.com/knowledge/how-to-break-nylon-dyneema-slings/
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JimT
climber
Munich
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Sep 17, 2014 - 02:43pm PT
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Cord (and tape) are tested using a large diameter drum and clamp system to get the actual strength of the material. Tested using karabiners you´d expect to see around 75% of the stated strength. Sewn slings are tested over 10mm pins and so their rating reflects normal usage (they are made from ca. 16kN material).
Slings doubled over a karabiner are generally weaker, the outer strand cuts the inner strand.
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Tvash
climber
Seattle
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Sep 17, 2014 - 02:52pm PT
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Does the % loss of strength from being wrapped around a biner differ between cord (6 to 7mm being the most commonly used) and runner material?
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JimT
climber
Munich
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Sep 18, 2014 - 12:09am PT
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There are so many different makes of cord, tape and karabiners that it would be impossible to test (or possible but waste of time). You just have to take a rough estimate of around 75% which covers most of the stuff that´s ever been tested. Some of the thinner Spectra cord has a reputation of being worse affected (Blue Water saw a reduction of 60% in some tests they did and I´ve seen similar from others) but since the stuff is strong anyway whether this is a problem is debatable.
Normally with appropriate knots the point of failure is at the karabiner so discussing the relative knot strength is a bit of a waste of time. Where it is relevant is if you tie into pieces with a clove hitch where things get marginal quickly.
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greyghost
Trad climber
Las Vegas, NV
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Sep 23, 2014 - 09:49am PT
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+1 for BG!
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Rosamond
Trad climber
Truckee, CA
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Sep 23, 2014 - 11:29am PT
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Good gawd, are people still arguing about this kind of shite? Here's a hint: there is no one single way to do most things safely in climbing. Personally, I always use a fully load equalized pair of dental floss runners on all my anchors. They're good to at least 8 pounds.
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donini
Trad climber
Ouray, Colorado
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Sep 23, 2014 - 11:34am PT
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+1 Rosamond!
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