|
|
|
|
hammerhead
Aug 2, 2005, 3:22 PM
Post #1 of 17
(2976 views)
Shortcut
Registered: Mar 3, 2004
Posts: 371
|
I couldn't get anyone to climb with last Sunday so I ended up going to the crag by myself (*sniff*) and spent the morning building anchors. I tried to simulate how I would do it on a multi-pitch climb while leading. So I geared up and tied in, climbed up 4 feet and proceeded to build away. It seems the easiest way was to put in a good piece and tie off with the rope using a clove-hitch (simulating that I'm still on belay) and then build a seperate anchor using 3-4 pieces and a cordelette. I must have built 8 anchors or so in different configurations in different cracks. One thing that I noted is that it's pretty hard not to rely on one crack feature for an anchor. I also built a rap anchor with a #7 hex and a #10 stopper. I equalized them with a knotted sliding X. It worked great. Then I walked to the top and rapped off of stout tree and cleaned my gear. I had a hard time getting that hex out. All in all it was a good day spent practicing one of the most important aspect of climbing.
How many of you use the loop created by the retraced figure 8 to belay/anchor?
|
|
|
|
|
jercech
Aug 2, 2005, 8:32 PM
Post #2 of 17
(2976 views)
Shortcut
Registered: Oct 12, 2004
Posts: 45
|
Well, that is exactly how I practiced building anchors before I felt confident in climbing on them.
As for building an anchor in one crack, it depends on how big the blocks are on either side. If the left side is one half of the mountain and the right is the other half, then don't worry about it. If the feature is a thin flake and you're putting cams behind it, then it makes sense to look for another feature.
Thirdly, belay from the belay loop. Belaying from the tie-in loop could put the figure eight knot under ring loading. In this configuration the 8 is prone to capsizing and rolling over, eating up rope until it rolls off the end.
|
|
|
|
|
clymber
Aug 2, 2005, 9:17 PM
Post #3 of 17
(2976 views)
Shortcut
Registered: Feb 8, 2002
Posts: 1259
|
i used to go out bouldering with a full rack and place gear all over the place...got some strange looks but it helped me out alot....get used to building anchors and placing gear in strange positions...only thing i didnt understand was the knoted sliding x you were talking about
|
|
|
|
|
jt512
Aug 2, 2005, 9:30 PM
Post #4 of 17
(2976 views)
Shortcut
Registered: Apr 12, 2001
Posts: 21904
|
In reply to: I also built a rap anchor with a #7 hex and a #10 stopper. I equalized them with a knotted sliding X. It worked great.
It's all fun and games until one piece blows, the sliding X extends, the remaining piece is shockloaded, the anchor fails, and you die. A rap anchor consisting of 2 seemingly good pieces is the last place you'd want to use a sliding X. Instead, statically equalize the pieces with two independent slings or a cordellete.
-Jay
|
|
|
|
|
hammerhead
Aug 2, 2005, 9:48 PM
Post #5 of 17
(2976 views)
Shortcut
Registered: Mar 3, 2004
Posts: 371
|
If you tie a knot in the "long leg" of the sliding x it minimizes the extension to an acceptable level. There would have been about 1 inch of extension. Plus because I equalized so both anchors shared the load it minimized the chance of one anchor failing. If most of the load had been on one anchor then it increase the chance of failure.
|
|
|
|
|
hex
Aug 2, 2005, 9:58 PM
Post #6 of 17
(2976 views)
Shortcut
Registered: Nov 7, 2003
Posts: 110
|
ok I highlighted what the original poster said... he did say he knotted the sliding X so tis all grand. Sounds like he learnt a lot.
In reply to: In reply to: I also built a rap anchor with a #7 hex and a #10 stopper. I equalized them with a knotted sliding X. It worked great. It's all fun and games until one piece blows, the sliding X extends, the remaining piece is shockloaded, the anchor fails, and you die. A rap anchor consisting of 2 seemingly good pieces is the last place you'd want to use a sliding X. Instead, statically equalize the pieces with two independent slings or a cordellete. -Jay |
|
|
|
|
claramie
Aug 2, 2005, 11:15 PM
Post #7 of 17
(2976 views)
Shortcut
Registered: Apr 26, 2004
Posts: 152
|
In reply to: How many of you use the loop created by the retraced figure 8 to belay/anchor?
Do you mean clip your belay device directly into the loop (of rope) without clipping through the belay loop too?
I think it is bad practice and you should use the belay loop or the anchor. My reasoning is that someday you might have to untie from your end of the rope while remaining on belay and that would just complicate matters.
CL
|
|
|
|
|
jt512
Aug 3, 2005, 5:41 PM
Post #8 of 17
(2976 views)
Shortcut
Registered: Apr 12, 2001
Posts: 21904
|
In reply to: ok I highlighted what the original poster said... he did say he knotted the sliding X so tis all grand. Sounds like he learnt a lot. In reply to: In reply to: I also built a rap anchor with a #7 hex and a #10 stopper. I equalized them with a knotted sliding X. It worked great. It's all fun and games until one piece blows, the sliding X extends, the remaining piece is shockloaded, the anchor fails, and you die. A rap anchor consisting of 2 seemingly good pieces is the last place you'd want to use a sliding X. Instead, statically equalize the pieces with two independent slings or a cordellete. -Jay
I missed that he said he knotted it. Still, what would be the point of a (knotted) sliding X in this situation? You have a rap anchor consisting of two nuts: this is a bit dicey, but not atypical for a situation when you'll be leaving gear. If the rap will be straight down, then you know the direction of loading, and a sliding X is unnecessary. If you have to pendulum on rappel, then a sliding X will do a slightly better job at maintaining equalization than a static anchor, but at a cost: the sliding X may cause the pieces to shift, and in this case, the peices are not cams, so we don't want them to shift even a little.
Beginners have a tendency to overuse the sldiding X. There are times when it is the best option (for instance, when the individual pieces are really marginal), but this will (hopefully) rarely be the case for a two-nut rap anchor.
-Jay
|
|
|
|
|
hammerhead
Aug 3, 2005, 5:54 PM
Post #9 of 17
(2976 views)
Shortcut
Registered: Mar 3, 2004
Posts: 371
|
I made the rap anchor in a corner on a ledge. I had to rap off at an angle so the force on the nuts, (actually a nut and a hex) would not have been easily equalized. At the time the sliding X, with the knot, was the best option. IMHO
|
|
|
|
|
jt512
Aug 3, 2005, 5:56 PM
Post #10 of 17
(2976 views)
Shortcut
Registered: Apr 12, 2001
Posts: 21904
|
In reply to: If you tie a knot in the "long leg" of the sliding x it minimizes the extension to an acceptable level. There would have been about 1 inch of extension. Plus because I equalized so both anchors shared the load it minimized the chance of one anchor failing. If most of the load had been on one anchor then it increase the chance of failure.
A sliding X is really only called for when the individual placements are so poor that if one failed, so would the other one, even if there were no shockloading. In that case, optimal equalization becomes the priority. Hopefully, such anchors are rare in your climbing. In contrast, when the individual placements are good, then you expect neither of them to fail, and the emphasis shifts from preventing the failure of a piece to minimizing the consequences in the extremely unlikely event of such a failure. Since the individual placements are solid, "perfect" equalization has little benefit over approximate equalization; however, preventing any extension is much better than allowing even an inch of extension in the unlikely event that one piece fails. Do you really want any shockloading, on your one last piece?
-Jay
|
|
|
|
|
hammerhead
Aug 3, 2005, 5:57 PM
Post #11 of 17
(2976 views)
Shortcut
Registered: Mar 3, 2004
Posts: 371
|
I made the rap anchor in a corner on a ledge. I had to rap off at an angle so the force on the nuts, (actually a nut and a hex) would not have been easily equalized. At the time the sliding X, with the knot, was the best option. IMHO
|
|
|
|
|
j_ung
Aug 3, 2005, 6:44 PM
Post #12 of 17
(2976 views)
Shortcut
Registered: Nov 21, 2003
Posts: 18690
|
I agree with Jay. Only use the sliding X (including the knotted sliding X) when you absolutely must have dynamic equalization. If you don't need it, take for example most rappel anchors, then pre-equalize instead.
|
|
|
|
|
pipsqueekspire
Aug 5, 2005, 6:07 AM
Post #13 of 17
(2976 views)
Shortcut
Registered: Nov 3, 2003
Posts: 222
|
Jay-
When in a verticle crack and making a bail anchor the pieces must be very closs together to get a fig 8 to fit in a double sling. When the clip in point to the pieces are more than about 18 inches apart in a verticle crack it is nearly impossible to get a double length sling into a knot tied equailzation because the fig 8 takes up so much of the sling that the lower piece is butted right up to the knot or its impossible to acutally equalize the 2 pieces in a downward pull.
I think a sliding X with a small knot on the long leg is just about perfect when making a bail anchor in a verticle crack. This uses minimal gear (1 sling) on the bail anchor and saves you from cutting up a cord until you must. I dont see a real risk of massive failure if both pieces are reasonably well placed since a rap anchor only needs to hold about 2-3 times body weight (even with a 3 inch shock load) and a well placed piece should be about to hald 2-3000lbs! I have been on several climbs where leaving behind a double length sling was the only option and in the verticle crack it was not possible to tie a fig 8. The sliding x with stopper knot was perfect and I felt fine with it.
The WORST time to use a sliding X for a rap anchor is when the two pieces are marginal. I totally 100% think you are WRONG about that. Using a sliding x on marginal gear is an invitation to disaster. (The one exception I can think of is when on lead and a quicky equliazation for an unpredictable direction of pull on 2 mank placements. Hopefully the distribution of the load will make both hold.) NEVER use an X on manky gear for a rap station! (which is what the poster is talking about)
Dont write off the x completely folks but a stopper knot (hopefully 2 of them) makes the rig a lot safer.
-pip
|
|
|
|
|
cracknut
Aug 5, 2005, 2:06 PM
Post #14 of 17
(2976 views)
Shortcut
Registered: Mar 4, 2005
Posts: 47
|
Another option the the slidding X is to tie of the anchors with clove hitches. Place your sling like you where making an American Triangle. Then tie off all three pieces with clove hitches in the sling. It's quick, static, and you can make adjustments to the direction of pull after it's tied.
|
|
|
|
|
cfnubbler
Aug 5, 2005, 2:20 PM
Post #15 of 17
(2976 views)
Shortcut
Registered: Oct 31, 2003
Posts: 628
|
In reply to: The WORST time to use a sliding X for a rap anchor is when the two pieces are marginal. I totally 100% think you are WRONG about that.
PSP, in perfect form...
That you're already in a terrible situation if you have to even consider these options is a given. But, assuming you're in the situation, you're wrong and Jay is right. We're trying to minimize the chance of catastophic anchor failure. Distributing the load as evenly as possible, and therefor minimizing the load on each individual piece, is the way to do so.
But you'd have bought it long before when you're deatholette snapped, sending you and your partner to the deck. :shock:
-Nubbler
|
|
|
|
|
cfnubbler
Aug 5, 2005, 2:21 PM
Post #16 of 17
(2976 views)
Shortcut
Registered: Oct 31, 2003
Posts: 628
|
In reply to: The WORST time to use a sliding X for a rap anchor is when the two pieces are marginal. I totally 100% think you are WRONG about that.
PSP, in perfect form...
That you're already in a terrible situation if you have to even consider these options is a given. But, assuming you're in the situation, you're wrong and Jay is right. We're trying to minimize the chance of catastophic anchor failure. Distributing the load as evenly as possible, and therefor minimizing the load on each individual piece, is the way to do so.
But you'd have bought it long before when your deatholette snapped, sending you and your partner to the deck. :shock:
-Nubbler
|
|
|
|
|
jt512
Aug 5, 2005, 4:46 PM
Post #17 of 17
(2976 views)
Shortcut
Registered: Apr 12, 2001
Posts: 21904
|
In reply to: When in a verticle crack and making a bail anchor the pieces must be very closs together to get a fig 8 to fit in a double sling.
If the sling is barely long enough, the first thing that ought to go is the figure 8, in favor of an overhand.
In reply to: I think a sliding X with a small knot on the long leg is just about perfect when making a bail anchor in a verticle [ sic] crack. This uses minimal gear (1 sling) on the bail anchor and saves you from cutting up a cord until you must.
Consider static equalizatuion using clove hitches, instead. On a rap you usually know the general direction of loading, so static equalization is almost as good as dynamic equalization, and with static equalization there is no extension. Preventing extension on the last piece standing between you and death is more important than achieving the best possible equalization, unless the placements are so poor that the individual placements would fail under a static load. In that case it doesn't matter if there is shockloading because the remaining piece would fail even under a static load. I've seen placements like that on routes (where in fact the two pieces together were pretty good, but individually wouldn't hold my water bottle), but I've never rapped from such a bad anchor, and hopefully never will have to.
-Jay
|
|
|
|
|
|
|
|
|
