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Fa310tx
Apr 25, 2009, 4:25 AM
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Tell me if this would work or if it would be a good idea...
I'm thinking about purchasing 100ish feet of static rope or webbing to create a top rope anchor with. My thought is that I could wrap one end around one tree (maybe 3 wraps with a figure 8 onto the part leaving the tree), take the rope to the cliff edge and then take the rest of the rope to the next tree (doing the same 3 wrap idea).
That would create a 2 point anchor using 1 rope and the biner would be able to slide to whatever point it needs to be for the climb. I've read that you should use 2 biners for top rope, but I assume that's because people are normally using 2 ropes/webbings.
Are there any problems with that setup?
JJ
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billl7
Apr 25, 2009, 4:39 AM
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The main thing that comes to mind is abrassion. As the anchor point gets moved around, the rope is going to scrape along the top of the cliff. Bad mojo.
Rope stretch and relaxation can do the same thing, and you'll have plenty of that.
Angles could be bad, too: a biggish angle from tree to biners to tree is a force multiplier.
You would probably spend less money and be better off anyway if you first studied a good anchor book and/or bribed someone experienced to help you out.
Bill
(This post was edited by billl7 on Apr 25, 2009, 4:40 AM)
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Terry2124
Apr 25, 2009, 5:17 AM
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Fa310tx wrote: Tell me if this would work or if it would be a good idea... I'm thinking about purchasing 100ish feet of static rope or webbing to create a top rope anchor with. My thought is that I could wrap one end around one tree (maybe 3 wraps with a figure 8 onto the part leaving the tree), take the rope to the cliff edge and then take the rest of the rope to the next tree (doing the same 3 wrap idea). That would create a 2 point anchor using 1 rope and the biner would be able to slide to whatever point it needs to be for the climb. I've read that you should use 2 biners for top rope, but I assume that's because people are normally using 2 ropes/webbings. Are there any problems with that setup? JJ
Its not a good idea to have moving parts as part of the anchor. There should be minimal leverage, balance without shock loading the anchor and redundancy.
There is more of a chance of something going wrong if part of the anchor moves.
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uni_jim
Apr 25, 2009, 6:31 AM
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Fa310tx wrote: I've read that you should use 2 biners for top rope, but I assume that's because people are normally using 2 ropes/webbings. Are there any problems with that setup? JJ
yoo use two binerz so dat yoo prevent the X-loading of said binerz, to provide a larger radius bend for da ropez, and for redun-dance-y (this means that when one uf yoor binerz unklipz, yoo don't suff her from a ground fall)
klimb safe!
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spikeddem
Apr 25, 2009, 6:33 AM
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Fa310tx wrote: Tell me if this would work or if it would be a good idea... I'm thinking about purchasing 100ish feet of static rope or webbing to create a top rope anchor with. My thought is that I could wrap one end around one tree (maybe 3 wraps with a figure 8 onto the part leaving the tree), take the rope to the cliff edge and then take the rest of the rope to the next tree (doing the same 3 wrap idea). That would create a 2 point anchor using 1 rope and the biner would be able to slide to whatever point it needs to be for the climb. I've read that you should use 2 biners for top rope, but I assume that's because people are normally using 2 ropes/webbings. Are there any problems with that setup? JJ
Yo, check it. See the part I bolded? Think about it. Why are you doing two trees? In case one of them fails, right? Have you really alleviated this? What happens if one of the trees fails? What happens to the carabiner?
You should tie a knot in the rope right at the top of where the climb finishes. Yes, you'll have to adjust it if you want to do a climb that finishes in a different spot right after, but at least this way you've got an actually redundant anchor. Your setup is not redundant (although it does distribute the forces between the trees).
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Fa310tx
Apr 25, 2009, 10:49 PM
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Terry2124 wrote: Its not a good idea to have moving parts as part of the anchor. There should be minimal leverage, balance without shock loading the anchor and redundancy.
I wasn't aware that the two anchor points was for redundancy. I thought it was just to distribute weight.
I also wasn't aware that the two biners were for redundancy, but to reduce the angle of the top-rope. I guess the angle wouldn't be that big of a deal, though, since it's 180 at the belay device.
So, then, it would be better to have 2 50's lengths of webbing than 1 100'.
Thanks for the info...
JJ
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bill413
Apr 25, 2009, 11:36 PM
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spikeddem gave some good advice.
Two biners - I consider that mandatory. I once came up to the top of a climb where the anchor point was a single locking carabiner. It had moved across the rock which resulted in the locking sleeve unscrewing and the gate being held open. Needless to say, I was a little perturbed.
Two biners - I don't terribly care if they are locking or not, but two with gates oppossed is what you should have.
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Terry2124
Apr 26, 2009, 7:51 PM
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bill413 wrote: spikeddem gave some good advice. Two biners - I consider that mandatory. I once came up to the top of a climb where the anchor point was a single locking carabiner. It had moved across the rock which resulted in the locking sleeve unscrewing and the gate being held open. Needless to say, I was a little perturbed. Two biners - I don't terribly care if they are locking or not, but two with gates oppossed is what you should have.
Yes absolutely, I agree.
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Terry2124
Apr 26, 2009, 8:02 PM
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Fa310tx wrote: Terry2124 wrote: Its not a good idea to have moving parts as part of the anchor. There should be minimal leverage, balance without shock loading the anchor and redundancy. Oh, I thought that's why people use the wrap 3 pull 2 setup (so that the biner can move around some). I wasn't aware that the two anchor points was for redundancy. I thought it was just to distribute weight. I also wasn't aware that the two biners were for redundancy, but to reduce the angle of the top-rope. I guess the angle wouldn't be that big of a deal, though, since it's 180 at the belay device. So, then, it would be better to have 2 50's lengths of webbing than 1 100'. Thanks for the info... JJ
I honestly can't tell if your being sarcastic with angles and degrees. My guess would be yes.
All I mentionned is that an anchor should not be moving around.
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Tree_wrangler
Apr 26, 2009, 8:37 PM
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In reply to: So, then, it would be better to have 2 50's lengths of webbing than 1 100'. Thanks for the info...
No, no, no.
I mean, yes, 2 50' slings (not lengths) would provide redundancy should either anchor fail, but it's not the slightest bit better than your 100' length of static line. In some cases it's more of a pain in the arse.
What Spikedem meant, was that you tie either end of your static line to the anchor. One wrap is fine, 2 or three have some advantages in certain circumstances.
Then, you find the point in the line, where, at the top of your pitch, both anchors are equally loaded. Your original concept for a setup (just a biner clipped on the line) will help you find this point because yes, it will move to the lowest point in the line.
Then, take that point in the line, and either tie in a figure eight, butterfly, or clovehitch (to name the most common), and make this your masterpoint for the belay/rappel. A clovehitch is most adjustable, left or right, with the butterfly being next easiest, and the eight the most difficult to adjust once tied and set.
Now you have your masterpoint, with force distributed more or less equally between your two anchors, but, due to the knot in the center, each strand to each anchor is independent of the other. So, should either anchor fail, or either strand break, the other will remain bombproof.
You can also use your static line to simultaneously tie off to 3 or 4 anchors, creating an equalized, many-times redundant master point, but just try to understand 2 for the moment. And, buy a book solely on anchors.
Got it?
(This post was edited by Tree_wrangler on Apr 26, 2009, 8:59 PM)
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Fa310tx
Apr 26, 2009, 10:12 PM
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Ah...
Thanks for the info. I figured that a single 100' static rope or webbing would be better than 2 50's (I would think that you could use it in more situations). I didn't realize that the knot at the middle biner was the important part, but I can definitely see the point.
I understand that the more anchors the better. I was simply assuming 2 because a lot of the trees around where I've been climbing are 30-50' back. I guess, if they were 20' then you could go with 3 anchors.
I appreciate the input and I'm looking at some anchor books on google books. It's good to see that I'm, at least, getting in the ball-park with some of this stuff. Now I need to find a friend that likes to climb. At the moment, it's just me.
JJ
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Terry2124
Apr 26, 2009, 10:23 PM
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John Long has a good book on anchors.
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Fa310tx
Apr 26, 2009, 11:42 PM
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Also, do you still double-wrap the rope at the top biner like gyms do on their top-rope bar?
I'm guessing so, but I wasn't sure since it would be a much tighter wrap.
JJ
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carabiner96
Apr 26, 2009, 11:46 PM
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Fa310tx wrote: Also, do you still double-wrap the rope at the top biner like gyms do on their top-rope bar? I'm guessing so, but I wasn't sure since it would be a much tighter wrap. JJ
No. You need to get yourself that book.
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patmay81
Apr 27, 2009, 12:54 AM
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I do that sort of thing quite a bit around boulders, trees etc. the only other thing I would recomend is puting a fig 8 on a bite at the clip in point, other wise you have a very non redundant anchor (even worse than the adt). also remember the 60 degree rule for anchors.
if you have issues with equalization and direction you can always use a third piece or tree and equalize between them with a sliding x.
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rocknice2
Apr 27, 2009, 2:37 AM
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patmay81 wrote: if you have issues with equalization and direction you can always use a third piece or tree and equalize between them with a sliding x.
I'm trying to picture this,
If he's using 1 strand of static line between two trees then adding a 3rd anchor in between the two, placing a sliding X will only work if you don't make a knot at the 3rd anchor. If you do make a knot then the sliding X is non-functional.
May it's that I'm not picturing it correctly.
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dead_horse_flats
Apr 27, 2009, 3:06 AM
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What you need to consider is do you have any single points of failure in the setup. If a biner gate opens, do you have a second biner. If you saw thru the rope/runner/webbing used for the anchor, do you have another independant line.
Basically just make sure each component in the anchor has a backup.
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Rudmin
Apr 27, 2009, 3:41 AM
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Tree_wrangler wrote: In reply to: So, then, it would be better to have 2 50's lengths of webbing than 1 100'. Thanks for the info... Now you have your masterpoint, with force distributed more or less equally between your two anchors, but, due to the knot in the center, each strand to each anchor is independent of the other. So, should either anchor fail, or either strand break, the other will remain bombproof.
If your anchor is a tree and that fails, I think you would be kind of fucked anyways, because you are now attached to a tree falling off a cliff.
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Tree_wrangler
Apr 27, 2009, 2:11 PM
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In reply to: If your anchor is a tree and that fails, I think you would be kind of fucked anyways, because you are now attached to a tree falling off a cliff.
Yep. But not always. Depends on the size of the tree. Evaluating anchor quality is always part of the game. And, there are plenty of trees/shrubs out there that are stronger than bolts. And plenty that are not.
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shoo
Apr 27, 2009, 2:56 PM
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Terry2124 wrote: Its not a good idea to have moving parts as part of the anchor. There should be minimal leverage, balance without shock loading the anchor and redundancy. There is more of a chance of something going wrong if part of the anchor moves.
This is not entirely true. There are many advantages to having moving parts to an anchor, most notably multi-directional equalization. However, given that this is a top-rope anchor, there is almost no need whatsoever to equalize in multiple directions, so the point is moot here.
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