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Ice Anchors

Original Post
Buff Johnson · · Unknown Hometown · Joined Dec 2005 · Points: 1,145

Just wondering what ideas people have for a good belay anchor?

I typically go for 2-3 screws, rigged with the rope or cord.

Sam Lightner, Jr. · · Lander, WY · Joined Apr 2006 · Points: 2,732

I also try and incorporate a tool into the anchor. They help.

abc · · Unknown Hometown · Joined Mar 2006 · Points: 210
Sam Lightner, Jr. wrote:I also try and incorporate a tool into the anchor. They help.
Testing done by Craig Leuban sp? suggests that tools used in the system are very weak. I don't remember the exact numbers, but I do remember being impressed enough to not use a single screw and my tool as the anchor anymore, like I used to normally do on north face alpine ice.

One thing I see all the time is people placing their anchor screws horizontal to each other, which is a huge mistake since ice is more prone to fracture in that direction. I always place one screw much higher than the other and a little offset.
kirra · · Unknown Hometown · Joined Feb 2006 · Points: 530

good points Brett. In my recent curiousity regarding the strength of Ice Threads (i.e. Abalakov, V-thread) I came across this experiment conducted by Petzl via video

Petzl video Ice threads vs Screws

best wishes for a safe season to everyone

Jeff Fox · · Delaware, OH · Joined Mar 2007 · Points: 1,320

Here's one I made yesterday. I used three screws, two 10cm and one 13cm (the ice was thin) staggered, two above one another, and one off to the side...it held!

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Mike Willig · · Unknown Hometown · Joined Jun 2004 · Points: 750

Is the Nalgene bottle mandatory?

jack roberts · · Unknown Hometown · Joined Oct 2002 · Points: 0

I will usually place one screw vertically above another but staggered to the side and sometimes if I think the ice isn't that great I'll drill four 16cm holes in the ice and use a cordelette as an equalizer and back that up with a long screw. I also hang a Nalgene container but it's usually filled with Scotch; just in case!!!

jack roberts · · Unknown Hometown · Joined Oct 2002 · Points: 0

Mike,

Let's do Deep Freeze. I hear it's in HUGE!!

SAL · · broomdigiddy · Joined Mar 2007 · Points: 790

sorry jack.
I already stole mike from ya for another project of mine.
Youll have to wait for this big stud :) :)
or. you can just jump in the element and meet us in moab!!!!

SAL · · broomdigiddy · Joined Mar 2007 · Points: 790
Mike Willig wrote:Is the Nalgene bottle mandatory?
It acts as a screamer in this given situation. Dont build an anchor with out one.
Jon Cheifitz · · Superior/Lafayette, Co · Joined Jun 2008 · Points: 90

Excellent Video..

Thanks for putting that up.

Micahisaac · · Fort Collins, CO · Joined Apr 2006 · Points: 80

Thanks for posting the vid Kirra, That was interesting.

Makes me wonder if you guys/gals back up your V-Threads when rapping? In bomber ice, I usually back it up with one screw (almost equalized, but has just a smidge of slack) as the heaviest person goes down first, then the screw is removed by the last person to rap. In theory, if the heaviest person didn't pull on the screw, the lightest person (always me) won't blow the anchor. The only problem with this is that the last person is rapping with absolutely no back up.
If the ice is poor, I will make a total of 2-3 V-Threads and equalize all of them.

Any thoughts? Suggestions?

kirra · · Unknown Hometown · Joined Feb 2006 · Points: 530

hi Micah yeah I have the same question about installing/removing the icescrew backup, perhaps better to rap 1st ~(:

but you'd be forfeiting that nalgene also

Jon Cheifitz wrote:Excellent Video.. Thanks for putting that up.
visuals to remember huh... {{shudder}}
mattb19 · · Unknown Hometown · Joined Jan 2007 · Points: 250

I have to agree with most on here with one screw on top of the other with a little bit of a stagger. I'll use 3 screws if I am not 100% positive of the ice. I have also been known to use a clump of bushes for an anchor. You gotta love obscure San Juan climbs.

As to the v- thread I always make the heaviest guys go down first with a backup screw. If the ice is not great I will make two v-threads and equalize them.

Buff Johnson · · Unknown Hometown · Joined Dec 2005 · Points: 1,145

Notes on threads:

Anyone incorporate a v-thread solely as the belay, and/or use a-threads, more than not just go for screws, or mix it up between types? (assume rock & trees aren't there)

-- as long as I see good ice off the anchor for the Jesus screw, I usually just go for a quick 2 screw set for the main anchor.

With rapping, the back-up screw -- horizontally above, at, or below the thread?

mattb19 · · Unknown Hometown · Joined Jan 2007 · Points: 250

As for the v-thread as an anchor by itself no. If I have a screw for a v-thread I will use that as well. I have been short on screws and used a v-thread as my secondary point. In fact I did two v-threads and then used the screw.

When backing up the v-thread I always put the screw above the v-thread. When building the rap I will make the v-thread below my lowest screw. I then will run the cord through the v-thread and tie it off. I then take an alpine draw and clip it to the best screw above the v-thread and take it down to the cord and tie it off equal with a carabiner equal to the cord through the v-thread. This way if the v-thread blows the top screw does not get shock loaded.

Jimbo · · Unknown Hometown · Joined Feb 2006 · Points: 1,310

It would have been nice if they had given numbers on the pull tests in that video. I can yank a fat bolt out of granite with enough force. That doesn't make it unsafe.
I've been rapping off single v threads (in good ice) since the early eighties. Never gave it a second thought. Of course back then we weren't clipping bolts every 8 feet either.
Come to think of it didn't we used to rap off a single bollard (cut out of snow) when necessary.

kirra · · Unknown Hometown · Joined Feb 2006 · Points: 530
Jimbo wrote:It would have been nice if they had given numbers on the pull tests in that video. I can yank a fat bolt out of granite with enough force.
as mentioned (in the video) the point was to test the comparative strength between an ice screw & an ice thread (under similar conditions) and the ice screw won (when most folks thought the thread would) This is also just a reminder "it's the quality of the ice that ofttimes determines the strength of the anchor". You could probably contact Petzl if your interest is in the numbers

sure you could probably snap a rope or anything else for that matter with enough force
EMT · · Unknown Hometown · Joined Jan 2008 · Points: 205

I wonder if webbing would have broken the ice at the same lb as the cord? Poss. more surface area would give it a little better chance? Or how about testing 8.8mm ropes? I've seen some people make just the holes and feed the rap rope straight in to the hole, rap, then pull ropes and leave no tat behind in the ice.

Buff Johnson · · Unknown Hometown · Joined Dec 2005 · Points: 1,145
Jimbo wrote:It would have been nice if they had given numbers on the pull tests in that video.
Here's some numbers from Beverly's & Attaway's test paper (Strike Rescue's website):

Horizontal v-thread failures: mean 11.3kN, low 5.2kN, high 16.8kN
Vertical v-threads (A-thread): mean 14.4 kN, low 10.9kN, high 17.5kN

Either shows significant safety margin to rappel from a single point in what was considered good ice. The A-thread shows a better anchor on average. There are parameters/variables within the construction testing of either method, which is why you get a wide variance in the horizontal v-threads.

The concept was to look at threads as a single anchor point to belay from; as well, they looked at rebored ice screws -- while results were stronger than expected, a multiple-point anchor distributing a load is more suitable for the belay anchor & using longer screws at certain angles for any install. Which makes sense to me. They didn't really address it, but the Jesus screw is pretty important to me as it takes the factor 2 energy away from this entire discussion.

Matt, with the screw back-up on a v-thread rap, the failure plane of a thread is actually above the thread. You want to put the back-up screw below the thread. I usually do that and rig with a screamer.
Buff Johnson · · Unknown Hometown · Joined Dec 2005 · Points: 1,145

Ah yes, threw that Jesus-screw term out there. Based on the Long's rock definition. The Jesus screw would be the first screw placed off the anchor. My learning was to place that good screw to protect the anchor when going off on the lead; after that, whatever I wanted/needed to do to keep from falling & climb under control in a fluid motion.

As well, the exit-screw placed before switching terrain types.

Guideline #1: Don't be a jerk.

Ice Climbing
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