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Posted

The other day i was out at one of our local ice crags. The ice had receeded a little bit and the ice was about 5 feet lower than the two bolt chain anchor that one would normally clip to and TR off of. I was somewhat surprised to see that a team of two was top roping off of a V-thread they had made, just below the bolt anchor. It was in good ice, but I still thought it was a bad choice.

 

I've rapped countless pitches off of a V-thread, and I trust their integrity to rappelling, but these guys didn't even have a backup screw in above the V-thread. Seemed like trouble waiting to happen to me.

 

Thoughts?

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Posted

Agreed that tr'ing off a single v-thread is a bad idea. I'd be okay with a good pair of v-threads or a v-thread backing up a couple of good screws. Hope they at least were running the rope through a locker or two.

Posted

Not even a backup screw? That's kind of odd and in my opinion stupid and lazy. What route?

 

This year my wife started leading; back in November she lead an ice route in Eagle river and tied off at the top on a patch of slings. I got to the top and found that the slings (at least one was from this year) were wrapped around a tree that had broken off about 2 feet above the anchors. I set up a new anchor, lifted the entire bunch of old slings and rap rings off the trunk and then was easily able to kick the old rotten tree trunk loose. There was a huge nice spruce 3 feet to the right with no anchors; why people couldn't take 5 extra minutes and rig a good rap anchor mystified me.

 

 

Posted

If you guys are so worried about V threads you should tke a minute next time your out make thread, then chip away some of the ice...repeat until you can get the thread to fail...bet you arent so worried after you do that

Posted

I don't think the loading is much different between rappelling and top roping. The issue here is having a back up. The vast majority of V-threads are secure, but you don't want to test that one in a thousand that fails without a backup screw. There is no reason not to have a backup. Takes a minute to put in. Presumably, the backup screw can be pulled when you are done.

 

Just be sure your backup is NOT loaded, otherwise the primary V-thread never is properly tested.

Posted
Yeah, rapping off of one V-thread always freaks me out a little bit. That seems pretty bold on their part, but I guess if it worked, who are we to complain? I wouldn't be doin it though :tdown:
WC, I've been thinking about your situation on Weeping Wall, which is not having a partner to go down first to test the V-thread while it is backed up. I've been meaning to ask, did you have it backed up with a screw? You can at least go on rappel while still at the anchor, bounce a couple of times, and THEN take out your backup.
Posted
WC, I've been thinking about your situation on Weeping Wall, which is not having a partner to go down first to test the V-thread while it is backed up. I've been meaning to ask, did you have it backed up with a screw? You can at least go on rappel while still at the anchor, bounce a couple of times, and THEN take out your backup.

 

Yes, before I pulled the screw you fell on and the other one I placed I did a triple check on that V-thread by: 1. Jerking on it by hand 2. Bouncing on it while on rappel 3. Shitting my pants as I rapped :P

  • 2 weeks later...
Posted

rapping off of a deep , tested 'v' is not ideal but acceptable. put the rope thru it. eliminates one link.

using a single 'v' for top roping is laziness-carelessness.

  • 3 weeks later...
Posted
the question has more to do with static versus dynamic loading.

I don't think the loading is much different between rappelling and top roping. The issue here is having a back up.

 

There is little difference to none in load while top roping or rappelling with the exception of if and when it's real purpose in safety were to come into play: to catch someone peeling off; which, is the dynamic load I'd be concerned about popping out a v-thread.

 

There's no way I'd want to top rope from a v-thread without some kind of back-up.

Posted
I don't think the loading is much different between rappelling and top roping. The issue here is having a back up.

 

There is little difference to none in load while top roping or rappelling...

 

Forgive me for pointing out teh obvious, but when you are on rappel there is only one body on the two strands of rope. When you are top-roping somebody, there are two people on either side of the rope. So there is a big difference in load...

Posted

Forgive me for pointing out the obvious, but when you are on rappel there is only one body on the two strands of rope. When you are top-roping somebody, there are two people on either side of the rope. So there is a big difference in load...

 

Right you are. The force in top-roping is double that of rappelling, even if there is no fall distance. This assumes negligible rope friction at the anchor, which is what we strive for anyway.

 

To see this see look at the first force diagram here

 

or the first pulley diagram here

 

Posted

I have mixed thoughts on this.

1st: V-threads that are in nice dry hard ice and are made using at least 19cm screws are supper strong: more so than one screw.

 

2nd: Top roping off screws can be bad if you don't cover them with snow to help eliminate melt. You can do the same with V- threads and ensure their stability.

 

3rd: If they use a locking biner on the rope through the v-thread it should be no problem, you won't be subject to rope burn and if you are belaying correctly the v-thread will not take a dynamic load, therefore the forces exerted on the v-thread will be static and the strength of the v-thread should be more then necessary to handle this force.

 

That being said, I would always add at least one screw usually two in separate areas of ice, staying with the standard of a three piece anchor.

Posted
Forgive me for pointing out the obvious, but when you are on rappel there is only one body on the two strands of rope. When you are top-roping somebody, there are two people on either side of the rope. So there is a big difference in load...

 

Right you are. The force in top-roping is double that of rappelling, even if there is no fall distance. This assumes negligible rope friction at the anchor, which is what we strive for anyway.

 

To see this see look at the first force diagram here

 

or the first pulley diagram here

Of course you are correct. Still the loads are nothing compared to a leader fall. All I really was saying is that it's so damn easy to put in a couple of UNLOADED backup screws, there is no reason not to.

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