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Abalakov (horizontal V) versus Anderson (vertical V) Threads?
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By Tommy Layback
From Sheridan, WY
Dec 28, 2012
Tom on Cloud Peak, Bighorn Mtns, WY.  Blacktooth and Mount Woolsey in the background.

I just read an interesting article claiming that a vertical V-thread (Anderson)is stronger (mean = 14 kN) than the standard horizontal V-thread (mean = 11.6 kN) that everyone I know uses/teaches :
Link to article

Does anyone know of any other testing/experience with these vertical or so-called Anderson threads? I do recall IFMGA guide, Eli Helmuth's, claim that ice has a tendency to fracture horizontally as opposed to vertically which would seem to favor the Anderson thread.


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By Buff Johnson
Dec 28, 2012
smiley face

The study shows where the failure occurs. You can pull the study off of Strike Rescue's website or the ITRS online. There are a couple other studies looking at lake ice and glacial ice; as well as another Beverly/Attaway on ice screws themselves.

You're probably thinking of two different ways to fail ice when you think about fracturing the ice horizontally as when you climb a pillar or curtain. With the anchors, the zone of tension occurs above, so it's not a matter of horizontal or vertical. So, as they found, this type of anchor behavior favors the A-thread in a belay situation; however the V-thread is still fine to rap off of.

This topic was also discussed in this forum, Ice Anchors, I think, if I remember correctly.


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By Martin le Roux
From Superior, CO
Dec 28, 2012
Stairway to Heaven

Tom Johannesmeyer wrote:
Does anyone know of any other testing/experience with these vertical or so-called Anderson threads?


Yes. See Smith, G., 2009, "Strength of V-Thread versus A-Thread Ice Anchors", www.itrsonline.org/PapersFolder/2009/SmithGordon-Allen2009_I>>>

Some points from this study and the Beverly & Attaway study mentioned above:

- The difference in means wasn't very big in absolute terms (11.6kN vs 14kN in Beverly & Attaway; 15.9kN vs 17.5kN in Smith)
- Sample sizes were small (10 A-thread tests in Beverly & Attaway; 5 in Smith) with lots of variability between samples
- Both studies were conducted under idealized conditions (horizontal lake ice in Beverly & Attaway; low-angle glacial ice on a warm and sunny day in Smith; slow-pull tests, not drop tests)
- All anchors were able to withstand loads much greater than a typical rappel (maybe 1 or 2kN?)

I guess the choice of horizontal vs vertical orientation could be important if for some reason you were belaying a leader directly off a thread. But in most real-life situations I can't see that it would make much difference. I'd be more concerned with finding the best quality ice in which to construct a thread and maximizing the cross-sectional area between anchor holes.


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By Crag Dweller
From New York, NY
Dec 28, 2012
My navigator keeps me from getting lost

Martin le Roux wrote:
...Both studies were conducted under idealized conditions... slow-pull tests, not drop tests)...


How would this affect the results in terms of which is stronger? I realize that drop tests may yield different failure loads but is there any reason to think that a drop test might prove a V-thread to be the stronger of the two?


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By XYZ
Dec 28, 2012

I'm sure all would agree that it (and usually everything else) depends on the type & quality of the ice. It's always safer to place more than one thread (horizontal or vertical or a mixture). One of the best uses of a day at the ice is placing Abalokovs ("V"s, named after the Russian who invented them). Do it a zillion times and early in the season when the ice is not yet climbable. Also practice when ice conditions change. Key to placing & feeling safe on them is speed (but not dangerously so). Take your time....as long as it's fast and bomber.

Craig Leubben did a lot of thread testing, some of which is depicted in his book. While he doesn't specifically address vertical threads, it's worth comparing his work to what is cited in the string. If verticals, make sure they are offset, i.e., not in a dead vertical line. With practice and one long cord, one can construct amazingly safe (but complex looking) V threads with two, even three points that can be equalized and clipped. These take a lot of practice.

Some people thread using webbing.....doesn't melt under tension as much as cord, however, ideally, the Vs aren't under a lot of tension for long periods. Webbing is also easier to "grab" with a thread tool (I use the Candela -- fabulous). I typically use cord & not webbing but tests show that webbing gives an extra edge of safety.


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By XYZ
Dec 28, 2012

If rappelling, the first person down (ideally, the heaviest person, if there is one) can back up the thread(s) with an ice screw (equalized). If all's fine, the second removes the screw and takes their turn down.


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By Ryan Williams
Administrator
From London (sort of)
Dec 28, 2012
El Chorro

Warren Robbins wrote:
If rappelling, the first person down (ideally, the heaviest person, if there is one) can back up the thread(s) with an ice screw (equalized). If all's fine, the second removes the screw and takes their turn down.


If you equalize the screw with the thread, are you really testing the thread? Wouldn't it only be taking half(ish) of the weight?


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By Buff Johnson
Dec 28, 2012
smiley face

just put a screw in below the thread with a screamer


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By robrobrobrob
Dec 28, 2012

How about thread less threads? Where you run the rope through instead of leaving tat? Any data on these? I like vertical for these because I somehow feel they are less likely to jam when pulling.

Thoughts?


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By XYZ
Dec 28, 2012

Ryan, good question. Buff's reply is a good one.

The goal of backing up the thread is two-fold: 1) protect the first one down (by weighting the thread (with whatever ratio looks good at the time), and 2) testing it because the second one down doesn't have the screw (unless left -- we've all done that).

Care must be taken not to shock load the screw or the least as possible. I probably gave the wrong impression when I said "equalize" the load. Bad wording. What I should have said is place the screw so that it's close to taking some of the load (but isn't) but let the thread be the test.

I did some V thread testing with Craig Leubben some years ago. It's quite amazing to see how much weight a well placed thread will take. Equally amazing is to see a well placed screw rip out, at least in our tests.

I think one of the scariest things to come across is someone else's threads that may or may not be well constructed and can't be evaluated (whatever that means) before/if you use them. The ice around the screw may have changed, you can't tell how deep they've been placed, etc. What CAN be evaluated is the final angle of the thread. I see too many constructed where the angle (just as in rock climbing pro) is too wide, i.e. the cord isn't long enough. I've probably made that mistake many times (apologies to those that got freaked out).

I think I've rarely relied on someone else's thread w/o placing another one. I take that back; I've probably relied on them more than I like to think because getting down expeditiously was important. Safely down.

That said, all of us know that multi-pitch routes are often finished at the end of the day (or perhaps more commonly, at night) and trying to get down ASAP tempts one to perhaps rely on anchors that might be dicey.

I've seen screws pull (outside of testing) when shock loaded but in my experience, I've not seen nor been an unfortunate victim of a V thread being ripped out. Has anyone seen this and if so, what happened? I've always been interested if anyone has real experience with this.


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By XYZ
Dec 28, 2012

SORRY, I said in my last comment just sent that it's hard to evaluate someone else's V thread because the "ice around the screw may have changed".

What I should have said is that the ice around the THREAD may have changed.

Apologies.


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By XYZ
Dec 28, 2012

robrobrobrob wrote:
How about thread less threads? Where you run the rope through instead of leaving tat? Any data on these? I like vertical for these because I somehow feel they are less likely to jam when pulling. Thoughts?



As a practical matter, you couldn't get a rope thru the "back" of the thread because it's "V" shaped, hence the name Abalakov gave it. It's often hard enough to grab (w/something designed for that purpose) & pull 6 - 8 ml cord.

I use 6,7,8 ml but once, we were out of threads & needed to save our screws for the lower part of a very hairy route (and it was at night but we had headlamps. We even had batteries).

Using the mini-saw on a Candela (multi-purpose wonder tool), we cut our 9.2 into "X" length...can't remember....and working with 22s, we sawed and sawed and sawed with them to make the holes large enough to take the rope and the back bend. Predictably, grabbing the end with the Candela was very difficult. I think it took us well over an hour - probably much longer - to get it. The discussion among the three of us alternated with "let's just use a screw" to "SCREW THIS" (trying to construct the thing).

For the same reason (the back shape of the V thread), it might be hard to pull & retrieve the rope because the free end might not make the turn. I don't think the circumstances would be such that you couldn't retrieve it but you might have to really pull hard. Depending on your stance below, that might be the kind of fun I'd pass on.

I think several factors could affect this, i.e., rope diameter, whether the rope is iced up, etc.

If you could successfully pull it, you might get a cold, hard gift along with it.

Anyone have the experience with a "thread-less threads?" I like the phrase....


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By XYZ
Dec 28, 2012

robrobrobrob wrote:
How about thread less threads? Where you run the rope through instead of leaving tat? Any data on these? I like vertical for these because I somehow feel they are less likely to jam when pulling. Thoughts?



You might be right about vertical, thread-less threads & pulling a rope. Just had a quick chat w/a BD tester friend and he thought it interesting enough that he might try to get some data on the idea. But he agreed that pulling might be the easiest part. Constructing it would be the trick, although it would be interesting to use two screws of different lengths to facilitate the pull. Don't know.

Maybe the info is in the links mentioned earlier; haven't had time to check them out but will now.


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By Buff Johnson
Dec 28, 2012
smiley face

Warren Robbins wrote:
... I've not seen nor been an unfortunate victim of a V thread being ripped out. Has anyone seen this and if so, what happened? I've always been interested if anyone has real experience with this.


I do it in a soft landing on snow to show their effectiveness. You just chip out the ice and jack the crap out of it with your weight jumping up and coming down on the anchor. I usually can't fail one until I get about a half inch of ice holding the thread (and that's after repeated attempts, so factor in ice fatigue, for what it's worth; even done 3-4' slack in system drops, too). I'm about 195-200lbs with gear on.


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By JonBates
From cody, wy
Dec 29, 2012

I've certainly never heard of or seen a v-thread fail but there are a few things that I think about when I use one. From the tests I've read about, the cordage usually seems to fail before the ice does. So that leads me to believe that if you eliminate the weakest link (cordage) and simply run your rope through the ice you've already made a stronger thread. I usually use 8.5mm double ropes with this technique and have had no trouble pulling the end through, granted I made a decent V. I've also used my 9.2 w/o plastic end caps or tape and have had no difficulty pulling it through either, both threading it and pulling my rope after I rap. Once I get the rope through I'll floss it back and forth to open up the junction of the screw holes a little more for ease of pulling it. I'd rather make my own threads than use someone else's piece of 6 mil. that's had who knows how many ropes pulled through it. Not to mention a lot less trash is left behind. It might not work for everyone but I've yet to have issues. Since the "anderson" is supposed to be stronger I tend to use it every time I can.


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