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oldguy
Apr 29, 2004, 2:06 PM
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I apologize if this has already been covered. I couldn't find it...
I recently went to a much-developed sport climbing area. On each of the routes, the top anchor consisted of two bolts, spaced 12 to 18 inches apart, with one chain link and one ring. The total "chain" length was about 2-3 inches on each bolt.
Thinking that I understood the physics involved, I insisted on extending these chains to lessen the angle. However, the common practice by the frequent users, was to simply tread the rope through the rings, using that to be lowered and for top-roping.
Disregarding the issue of the wear on the rings, is this safe? Is the load too high on the bolts with this configuration? I don't have a clue about the math but I do plan to go back. It would be much simpler to use them like everyone else, but I want to be safe.
Thanks
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jkarns
Apr 29, 2004, 2:11 PM
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Is it safe for toproping? Assuming the botls are good, sure!
Is it the right thing to do? NO! Don't wear those anchors out! If you're gonna TR it, throw a draw on each bolt.
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grundlebug
Apr 29, 2004, 3:15 PM
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Bomber enough to rap off too, as long as there are no unusual signs of the bolts being manky, rusted out, quarter-inch death traps. But given your description, it sounds like pretty standard sport climbing fare.
Rapping off is better than lowering because there's no wear from the rope rubbing through the chains.
A single bolt is at least strong enough to handle dynamic 6 foot lead falls, so the double bolt anchor is going to handle your static top rope or rappelling forces no problem. No sweat.
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sarcat
Apr 29, 2004, 3:45 PM
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I think what oldguy is asking is the angle safe for the weight put on it. Yes is the answer since you are top roping and/or lowering. The rope is only at 90 deg. around each rap. ring compared to a 180 deg. bend around a single biner on a draw. Because of the dynamics of the rope you aren't compromising the anchors either. It may look like a lot of force pulling them together bue it's not.
If you don't like it you could take a bunch of 3/8" quick links with you the next time and make them longer.
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qpang
Apr 29, 2004, 4:13 PM
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It is true when setting up an anchor with gear that you want a suitable angle from each anchor so that the load is shared equally. When set up properly two anchors should each be taking 50% of the load, and it is true that with too sharp of an angle the load on each anchor will be more like 75% each, or even 100% each as the angle increases. However when toproping a sport route, this isn't as big a factor since both of those bolts should be pretty bomber for any forces that they should experience in TR or Rappelling. So even if each bolt is taking 100% load, they should still be plenty strong. Going through both of them is more about redundancy than splitting the load. http://www.mercurymessenger.org/Images/anchor.jpg You would be dealing with the middle situation I think, which still isn't as bad as the first setup.
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oldguy
Apr 29, 2004, 9:34 PM
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Yes, the middle illustration is what I'm talking about. So I'll just chill and join the crowd.
However, this brings up another question. In the first illustration, cannot the forces on each bolt exceed 100%? This is very similar to an archer pulling the string on a bow. We would never be strong enough to bend the bow without the physics involved in pulling the midpoint of the string.
Oh well, for climbers, just don't do the first one.
Thanks for the input.
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caughtinside
Apr 29, 2004, 9:37 PM
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In reply to: Is it safe for toproping? Assuming the botls are good, sure! Is it the right thing to do? NO! Don't wear those anchors out! If you're gonna TR it, throw a draw on each bolt.
This is the correct answer. DON'T TR OFF FIXED GEAR! It wears it out. TR off your own gear, then clean when you're done.
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zoob
Apr 29, 2004, 11:19 PM
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Hey old guy.. You do not have to join the crowd! Do what you feel is the most sound and comfortable for yourself. You have the right to judge for your self. Although in the conversations above most sport climbers may use the illustration marked "better", why not shoot for the best of the situations and place and anchor(with a low angle) on the bolts for the top ropping. I feel that this does not take alot of extra time, it is the safest situation, definatly reduces wear on the bolts/rings. So when you get to the bolts, anchor in with a daisy chain or cow's tail (etc) and set up an anchor!. If the route, fatigue,weather dictates time constrains (should not in sport climbing) then possible down grade from the "best" option to a safe but less time consuming anchor system. While doing sport stuff, you may as well set the best anchor you can...there is no rush.
Cheers
( Just for fun, I sometimes tell my partner that I would back up a Redwood!)
Climb safe and have fun.
Zoob :D
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punkclimber52
Apr 30, 2004, 12:25 AM
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When i first started climbing my partner (The guy that got me into climbing) never set up his own gear on fixed TR anchors. It wasn't until i was out on the crag with another partner and i saw other climbers using their own gear that i realized, "oh, i wonder if i shouldn't TR like this."
I'm still having to learn some of the more ethical things as i go, since my first partner wasn't very ethical.
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climbingpride
Apr 30, 2004, 2:11 AM
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I always put up my own slings or draws on the bolts. I never TR threw the bolts. When i see chains i use them to make cleaning easier.
I get to the top, clip into the bottom links of each chain -with whatever set up you use, draws or fixed daisey- then pull up slack and do a simple overhand knot. I clip the loop onto some part of my harness to prevent droping the rope when feeding it back threw the next link or so up from where i cliped in. After feeding enough of the rope threw so that it touches the ground, i feed the rope threw my ATC and sinch up to be able to unclip myself from the chains. This basicly eliminates the forces put on your attachments when you try to take them out and rap back down. I'v had many a struggle trying to unclip from bolts without these chains, because of the force the rope puts on bieneers when you weight the rope.
I hope that made sense. Oh well.
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dfoerstel
May 4, 2004, 2:54 PM
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[quote="climbingpride"]I always put up my own slings or draws on the bolts. I never TR threw the bolts. When i see chains i use them to make cleaning easier.
Slightly off topic but does anyone use locking carabiners on the quickdraws when setting up a toprope on a sport climb?
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sarcat
May 4, 2004, 3:16 PM
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I carry some 24" slings that I use at the anchor points. When the anchors are further apart they still can make the "best" angle situation. When breaking down the achor I always rap. off the bolts not lower.
No my slings don't have locking carabiners. Make sure the bottom biners oppose each other.
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timstich
May 4, 2004, 3:24 PM
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You are doing it right by extending the anchors. The chain on a bolt method of anchor building is without a doubt one of the crappiest, cheesy confuksterations out there. Add a frigging hanger you dirtbag dumbasses. That way, you can use a quicklink to attach the chains and simply remove worn chain later by unscrewing the links. Otherwise you need bolt cutters. Duh. Short sightedness at its worst.
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lordjim
May 4, 2004, 3:32 PM
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In reply to: Slightly off topic but does anyone use locking carabiners on the quickdraws when setting up a toprope on a sport climb?
Even more off topic: yup I do. I have two draws that I use for anchors for TRing sport. A pair of long Metolious Slings with Petzl locking ovals. Put them in opposite and opposing too. Since it's the last thing whoever is TRing comes to I wanted something that has the smallest chance of accidential opening.
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jv
May 4, 2004, 3:55 PM
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I think the side-by-side bolt arrangement is a holdover from the early days. It was common to find these on multipitch routes with several old slings through both bolts, forming the "American death triangle." I don't know why people haven't adopted the vertical alignment, joining the upper and lower bolts with chain link.
If equipped with quick links or something else attached to the hangers, I rap on these without worrying about it. I have not heard of a failure of hefty, modern bolts in this configuration, even when set up as in the diagram on the left above. But as pointed out by others already, you don't want to top rope off the quick links, etc., anyway. To reduce wear and tear on the fixed anchor, attach your own slings and biners for top roping.
JV
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roc_klimber
May 4, 2004, 4:29 PM
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I use one quickdraw with the little metolius locking d's on both ends, and a regular one. That way it is just as fast, but I have one locker on the rope and anchor. I guess it is just about your own comfort level.
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dfoerstel
May 4, 2004, 7:21 PM
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Thanks for the replies from my slightly off topic response. It does seem that each individuals level of comfort will ultimitely determine whether to use lockers or not. I just see so many people throwing up a couple of quickdraws without hesitation.
Dave
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