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SillyG
Aug 21, 2011, 2:03 AM
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I just finished a top rope management class to learn the basics of setting up my own anchors. We used 6mm cord to set the anchors, which seems fine to me, but after reading some of the posts on this board I'm starting to wonder...
I just bought 3 lengths of 50ft 6mm cord from REI; sales guy said this was fine for setting anchors. What do you guys think? OK for basic top rope anchor setting, or did I make a mistake?
Thanks!
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redonkulus
Aug 21, 2011, 3:26 AM
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SillyG wrote: I just finished a top rope management class to learn the basics of setting up my own anchors. We used 6mm cord to set the anchors, which seems fine to me, but after reading some of the posts on this board I'm starting to wonder... I just bought 3 lengths of 50ft 6mm cord from REI; sales guy said this was fine for setting anchors. What do you guys think? OK for basic top rope anchor setting, or did I make a mistake? Thanks!
Holy shit! That's almost a whole rope right there! Why 3 lengths? Why 50 Ft? Also, I'm sure if you set it up right 6mm is probably fine, but it's skinny enough that it doesnt exactly look confidence inspiring. Personally, when building anchors I use a 25' length of 8mm, but i'd use 7mm just as well. I dunno, see what everyone else thinks, but I personally wouldn't feel quite as comfortable on it, probably for no reason though.
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mbrd
Aug 21, 2011, 3:59 AM
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uh- it won't be long before you get much better responses than mine, but for the time being, how exactly is it being suggested that this 6mm accessory cord be applied?
i guess my thinking here is that it is probably okay under nearly any circumstances, but i grew up (or failed to grow up) with the paradigm of using goldline, and later perlon for toprope anchors to fixed objects. old climbing rope or static line jacketed with one inch tubular webbing has been my anchor preference ever since.
put another way, the bigger the better.
part of the formula here is longevity of anchor material.
of course, thirty years ago, we also had to consider how long it took the drunken rubes at the top of the crag to "jokingly" cut through our anchors.
it was a good incentive for learning to lead.
conversely, if you are setting gear for toprope anchors, the weakest link might not be the 6mm acc cord.
anyway, 6mm? if everything else is sound, you'll be fine for longer than it takes to get tired of toproping, and start leading, leaving the 6mm stashed in some closet, or chopped into prussiks for a rainy day.
you're alright for now, just keep an eye on the wear, and always seek to employ redundant anchors.
if gently tapped, folks at the crags you climb will provide the more specific advice you need for each particular venue.
the more weathered and curmudgeonly the folk, the better the advice will be.
try to find an old guy tapping a flask between moments of his partner's progress on toprope. you want the guy that drinks with his non-brake hand.
do consider the potential merit of jacketing the accessory cord with tubular webbing as a protective layer. do also, keep in mind that this complicates exhaustive inspection of your anchors, which is kind of an important periodic thing to do. look at what other people are currently using where you choose to climb. a lot of anchor rigging is intuitive; if it looks wrong, it probably is- if it looks solid, look again to make sure that it is. then check one more time.
make sure you spend more time getting counsel from climbers in the three dimensional world, than you do getting it online.
but yeah, for now, all other things being square, 6mm should be okay.
(excellent! i got to patronize somebody, and temper it with what my walnut sized brain would pass on as sage counsel! i love the worldinterwidenetwebs)
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TarHeelEMT
Aug 21, 2011, 4:04 AM
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It's thinner than I would use for top rope anchors, but there's no need to buy new cord. Since you have three 50 foot lenghts (holy crap that's long), you can just double or triple them up for a bomber anchor.
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redonkulus
Aug 21, 2011, 4:18 AM
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mbrd wrote: try to find an old guy tapping a flask between moments of his partner's progress on toprope. you want the guy that drinks with his non-brake hand.
Just awesome.
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mbrd
Aug 21, 2011, 4:39 AM
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TarHeelEMT wrote: (holy crap that's long), you can just double or triple them up for a bomber anchor.
inbloodydeed....
with that kind of length you can practise whacky cartoon length cordelette rigging.
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rescueman
Aug 21, 2011, 5:10 AM
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Jeezum Crow! 6 mm?
What happened to 1" tubular webbing, or short lengths of 7/16" static line?
6mm accessory cord has a breaking strength of about 2,000 lbs. With a standard 10:1 safety factor, that means you shouldn't have more than a 200 lb working load. A short fall and you're putting maybe double that on the rope and doubling that force at the anchor.
Also, a 6mm cord has a lot fewer fibers to cut or wear through if abraded over an edge or a sharp-crystalled rock.
What's your life worth to you?
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mbrd
Aug 21, 2011, 5:27 AM
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this would be the sort of "better answer" i was previously referring to.
when in doubt, go stout.
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surfstar
Aug 21, 2011, 5:28 AM
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rescueman wrote: Jeezum Crow! 6 mm? 6mm accessory cord has a breaking strength of about 2,000 lbs. With a standard 10:1 safety factor, that means you shouldn't have more than a 200 lb working load. A short fall and you're putting maybe double that on the rope and doubling that force at the anchor.
I better buy some 11mm static for my cordellete!
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TarHeelEMT
Aug 21, 2011, 5:31 AM
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rescueman wrote: Jeezum Crow! 6 mm? What happened to 1" tubular webbing, or short lengths of 7/16" static line? 6mm accessory cord has a breaking strength of about 2,000 lbs. With a standard 10:1 safety factor, that means you shouldn't have more than a 200 lb working load. A short fall and you're putting maybe double that on the rope and doubling that force at the anchor. Also, a 6mm cord has a lot fewer fibers to cut or wear through if abraded over an edge or a sharp-crystalled rock. What's your life worth to you?
Since when is a 10:1 safety factor "standard" for top ropes? That's rescue talk. Standard is good enough to hold the greatest possible force you could put on it, not ten times the greatest possible force you could put on it. If that were the "standard", nobody could climb on gear.
The three 6mm cords that he owns when used together (he has the length to do it) would provide far more abrasion resistance than a single strand made from a comparable amount of material, and certainly moreso than a 7/16" static line.
Despite your "what's your life worth to you quip," it doesn't sound like he needs to buy anything new at all - he just needs to rig with redundancy.
(This post was edited by TarHeelEMT on Aug 21, 2011, 5:36 AM)
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mbrd
Aug 21, 2011, 5:41 AM
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oh and, by the way, rescueman just popped the top on the frothy ale that is the madness of breaking strength versus working load limit.
what the hell is wrong with you rescueman, this kid's cherry is still intact!
okay, now if you have read this, your are qualified to be an entertainment industry, or recovery rigger in thirty six out of forty eight major markets.
you might be able to tend lunchboxes for yosar...
makes climbing all the more inviting, doesn't it?
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mbrd
Aug 21, 2011, 6:09 AM
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you bloody bastard! see the shit you started?
and i don't want to hear any of that "but i was just asking a question" sniveling.
NO ONE PURSUING ENLIGHTENMENT TRUSTS A LIVING ENTITY TO DISPENSE IT.
i tried to help you, but it wasn't enough. now you have gone too far, and the wrath of shiva will soon befall you.
that rei guy is probably gonna end up with a tainted shrimp salad, too.
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SillyG
Aug 21, 2011, 9:57 AM
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Thanks for the advice everyone. To elaborate, I'm using the cord to clove-hitch to natural objects (trees/rocks), equalize two strands, and then setup on the master point.
We learned using two strands for redundancy; I've seen some people suggest three redundancies. When I asked, I was told 3 redundancies for placed gear, two is fine for fixed top rope points.
As an aside, about the 50ft lengths, I figured it would make it easier setting up using natural objects that are a bit back from the cliff. Since 6mm is pretty thin/light, 3 lengths isn't much to carry.
Thanks again!
(This post was edited by SillyG on Aug 21, 2011, 10:04 AM)
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patto
Aug 21, 2011, 10:44 AM
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SillyG wrote: Thanks for the advice everyone. To elaborate, I'm using the cord to clove-hitch to natural objects (trees/rocks), equalize two strands, and then setup on the master point. We learned using two strands for redundancy; I've seen some people suggest three redundancies. When I asked, I was told 3 redundancies for placed gear, two is fine for fixed top rope points. As an aside, about the 50ft lengths, I figured it would make it easier setting up using natural objects that are a bit back from the cliff. Since 6mm is pretty thin/light, 3 lengths isn't much to carry. Thanks again!
I'm still not clear about your set up here. I would strongly advise AGAINST using a single strand per protection. 6mm is only 8.4 kN which is more like 6kN after tying a knot.
At least 4 stands should be going to the central anchor point if you want strength and redundancy.
Even so be very careful. A poorly managed top rope setup could EASILY abrade through 6mm very quickly.
6mm is fine if you manage things properly. But it is potential disaster if you don't know what you're doing.
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acorneau
Aug 21, 2011, 9:17 PM
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6mm cord...
-If it's set up as a "Quad" you're bomber.
-If it's set up as a 3-point cordelette, you're good.
-If it's set up as a 2-point cordelette or equalette you're pushing it a bit.
Again, without knowing exactly how you intend to use these it's hard for us to say one way or another.
Edit to add:
You say you're going to be using trees or boulders back from the edge. That means your material is going to be going across an edge so your master point is out on the face of the climb.
The 6mm is not going to take the abuse of running over a sharp edge as well as something like a burly static rope (7/16") or multiple strands of 1" webbing. Make sure to pad any edge that the material might be rubbing on.
(This post was edited by acorneau on Aug 21, 2011, 9:22 PM)
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TarHeelEMT
Aug 21, 2011, 10:02 PM
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I just want to make sure we're clear. Although I say you're fine with three 6mm cords, under no circumstances should you use a single 6mm, unless set up as a quad as mentioned by acorneau.
Why would you clove hitch to a tree? That makes only a single strand going to the tree (very weak). Tie your cord into a loop with a double fisherman's, wrap the tree, and then tie an overhand to create a master point. It's much more bomber that way. With 50' cords, you shouldn't have any problem doing this.
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sherpa79
Aug 22, 2011, 12:01 AM
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rescueman wrote: Jeezum Crow! 6 mm? What happened to 1" tubular webbing, or short lengths of 7/16" static line? 6mm accessory cord has a breaking strength of about 2,000 lbs. With a standard 10:1 safety factor, that means you shouldn't have more than a 200 lb working load. A short fall and you're putting maybe double that on the rope and doubling that force at the anchor. Also, a 6mm cord has a lot fewer fibers to cut or wear through if abraded over an edge or a sharp-crystalled rock. What's your life worth to you?
This would all be very disconcerting if you were using a single strand of 6 mil to belay from, but you aren't. My anchor cords, if I'm not using the rope to build and anchor, are either 6 or 7mil.
However, that said, anchor cords whatever their configuration are used differently and wear differently in a lead climbing vs. toproping scenarios. For topropes I typically use webbing. Mostly because these cords DO generally get loaded over edges , are therefore subject to a lot more abuse, and aren't watched as closely as cordlettes are in lead climbing scenarios. That and I don't want to fuzz up the anchor cords I use most of the time just to top rope some.
Is 6mil strong enough? Doubled, set on redundant anchor points and free from sharp edges. Yes.
Would I use 6mil for my toprope set ups? Maybe, if I had 150 feet of it!
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rescueman
Aug 22, 2011, 1:14 AM
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TarHeelEMT wrote: Since when is a 10:1 safety factor "standard" for top ropes? That's rescue talk...If that were the "standard", nobody could climb on gear.
Of course, there is no standard for recreational uses. But that's not just "rescue talk". The rigging industry uses a 5:1 safety factor for all non-life-support vertical operations, and 10:1 is the standard worldwide for life-support operations (except in Australia where they're happy with 8:1).
In reply to: The three 6mm cords that he owns when used together...would provide far more abrasion resistance than a single strand made from a comparable amount of material, and certainly moreso than a 7/16" static line.
A small cord cuts almost instantaneously, while a larger cord takes much more time. (This was proven in tests conducted by some fellow cavers). If each leg of the cordellete weren't independently tied at the master point, then a single failure could result in a system failure.
In reply to: he just needs to rig with redundancy.
Whoever trained SillyG in "top rope management" should be tarred and feathered and run out of town.
(This post was edited by rescueman on Aug 22, 2011, 5:54 PM)
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tH1e-swiN1e
Aug 22, 2011, 2:35 AM
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I guess your safety would all depend on how your anchors are set up. I personally wouldnt use 6mm.
Chop those up and use them for prusiks. 1" webbing FTW
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TarheelJD
Aug 22, 2011, 2:38 AM
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Read through the bottom of the first page of this thread: http://www.rockclimbing.com/..._reply;so=ASC;mh=25;
Like Acorneau said, it all depends on how you use the cord as an anchor. If you are setting top ropes on two bolt anchors near the edge of the cliff just tie a quad and be done with it. That being said, 8mm PMI cord is $.55 a ft at REI, just go buy 25 ft or 50 ft or whatever you need to properly construct anchor where you normally climb. The 8mm cord will hold up a lot better than the 6mm cord and you can feel better about tying an equalette instead of a quad if the circumstances dictate such. It's only $20 bucks.
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summerprophet
Aug 22, 2011, 4:30 AM
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acorneau wrote: 6mm cord... -If it's set up as a "Quad" you're bomber. -If it's set up as a 3-point cordelette, you're good. -If it's set up as a 2-point cordelette or equalette you're pushing it a bit.
acorneau nailed it.
I am a climbing guide, and this is what I teach.
Assuming 6mm cord has a breaking strength of 6-7kN, two stands of it still falls shy of 20kN which is an acceptable minimum for anchors.
So if you are using all three strands, you are golden, If you are doubling any of the strands, you are golden.
Personally I like 6mm cord, a 20-30 foot length bundles well on my harness, and 5.5mm is just two damn expensive for such a short lifespan.
Just be aware of the limitations, you want to see three loaded strands at your top rope anchor...... or be prepared to do the math factoring to see if you can get by with less than a 20kN anchor.
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gmggg
Aug 22, 2011, 3:06 PM
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rescueman wrote: Jeezum Crow! 6 mm? What happened to 1" tubular webbing, or short lengths of 7/16" static line? 6mm accessory cord has a breaking strength of about 2,000 lbs. With a standard 10:1 safety factor, that means you shouldn't have more than a 200 lb working load. A short fall and you're putting maybe double that on the rope and doubling that force at the anchor. Also, a 6mm cord has a lot fewer fibers to cut or wear through if abraded over an edge or a sharp-crystalled rock. What's your life worth to you?
I use 6mm for top rope set ups pretty often. If you need to extend waaay back to trees or other features it is a great light weight low bulk set up.
With that said I prefer 1" tubular for normal set ups, mostly because of the abrasion issue that rescueman stated.
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gmggg
Aug 22, 2011, 3:14 PM
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sherpa79 wrote: Is 6mil strong enough? Doubled, set on redundant anchor points and free from sharp edges. Yes. Would I use 6mil for my toprope set ups? Maybe, if I had 150 feet of it!
Ohh. good point, just to clarify I was only talking about using 6mm to extend the legs of an anchor, and when doing so it should be tied into a loop and not used as a single line.
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rescueman
Aug 22, 2011, 3:25 PM
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gmggg wrote: I use 6mm for top rope set ups pretty often. If you need to extend waaay back to trees or other features it is a great light weight low bulk set up. With that said I prefer 1" tubular for normal set ups, mostly because of the abrasion issue that rescueman stated.
I should add that there are two issues here: not only is 6mm much quicker to abrade or cut than a larger diameter cord, but it will also have a lot more stretch - even multiple strands - and, if it's extended over an edge, there will be a lot more sawing action.
In trad climbing, it's reasonable to use lightweight gear for anchoring and make up for it with redundancy. In top-roping, there's no excuse not to use heavier anchor cordage on stronger anchors with as little stretch as possible when extending over an edge.
You leave a trad belay anchor and move on. In top-roping, you might climb for hours on one anchor setup and it's going to see a lot more abuse.
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dan2see
Aug 22, 2011, 3:39 PM
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SillyG wrote: I just finished a top rope management class to learn the basics of setting up my own anchors. We used 6mm cord to set the anchors, which seems fine to me, but after reading some of the posts on this board I'm starting to wonder... I just bought 3 lengths of 50ft 6mm cord from REI; sales guy said this was fine for setting anchors. What do you guys think? OK for basic top rope anchor setting, or did I make a mistake? Thanks!
Thanks for showing us your alternate method for anchor-building. Ideas like this are interesting and should always be analyzed.
But ... (hey you knew there'd be a "but")
Do it right. Do what everybody else does.
Use robust cord or slings. Just like everybody else.
Frankly, if I was in your climbing group, I'd quit top-roping and stick to scrambles. At least that way, I wouldn't worry how somebody's negligence could kill me.
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