v-thread (Abalakov) musings

[Kevin_Matlock]

Combination of lack of experience with v-theads and, well, I'm just bored at work so my mind was wandering... what are your thoughts/experiences with Abalakovs? Please consider this a one-stop-shopping area to dump your knowledge about them (mods: pls make this a sticky if it amounts to anything)

 

Some random questions to discuss:

 

( This link from way back when discusses some other questions.)

 

-I've read in some places that this is a "new" technique. Wondering how long this has been around and what the hell people did before.... leaver screws?

 

-is a 22 cm screw mandatory when making one? I get the whole point that you want the most depth into the ice as possible, but what happens if you only have a 17cm? Has anybody heard of someone ballsy enough to make one from a stubby?!?!?

 

-if you run cord through it, how do you tie the ends: double fishermans? Some other mysterious "v-thread knot"?

 

-for that matter, do you prefer cord or webbing? (assume a water knot if webbing is used)

 

-these used only for pro -OR- for rapping? What about used for a top rope? Too sketchy to trust in an abusive TR scenario?

 

-do you "always" prepare 2 of them for redundancy or is this only for less-than-perfect ice; in other words if the ice allows, is it sometimes OK to rap off a single v-thread?

 

Anything else you wish to toss in feel free.

 

[catbirdseat]

-I've read in some places that this is a "new" technique. Wondering how long this has been around and what the hell people did before.... leaver screws?

Not really so new. People either rapped off trees or pounded in pieces of electrical conduit.

 

-is a 22 cm screw mandatory when making one? I get the whole point that you want the most depth into the ice as possible, but what happens if you only have a 17cm? Has anybody heard of someone ballsy enough to make one from a stubby?!?!?

You could probably get away with a 17, but not a stubby.

 

-if you run cord through it, how do you tie the ends: double fishermans? Some other mysterious "v-thread knot"?

Doesn't matter. I'd use a double fisherman. You don't care whether it can be untied- you're leaving it.

 

-for that matter, do you prefer cord or webbing? (assume a water knot if webbing is used)

Doesn't matter. Cord is a little easier to thread than 9/16" webbing.

 

-these used only for pro -OR- for rapping? What about used for a top rope? Too sketchy to trust in an abusive TR scenario?

They are ideal for top roping. Better than screws. Equalize two of them.

 

-do you "always" prepare 2 of them for redundancy or is this only for less-than-perfect ice; in other words if the ice allows, is it sometimes OK to rap off a single v-thread?

 

One is okay in really good ice. Otherwise two is better.

[TrogdortheBurninator]

Rapping off a single thread in good ice is fine. I usually place an unweighted screw nearby as a backup for the first (heavier) rappeler. 2nd rappeler pulls the backup.

[Alpinfox]

One V-thread in good ice is fine as an anchor. I've always done it with 22cm screws, but 17cm would probably work in a pinch. I always back the V-thread up with at least one unweighted screw. Heavy guys go first. Last one to rap takes the backup off.

 

I've used fishermans and overhand knots for tying the knot in the threaded cord. I've never used webbing, but a waterknot would be fine.

 

I pretty much only use V-threads for rapping because they take too long to build to be used as pro. On a popular route you might be able to use pre-made V-threads as pro. However, I'd be leery of trusting a random piece of cord sticking out of the ice (it could be the tail of a V-thread with the floppy end just frozen an inch or so into the ice). Inspect a leftover V-thread VERY carefully and definitely back it up.

 

A cool trick that I've never tried, but supposedly works: Thread your rope directly through the V-thread to avoid having to leave any cord. Steve House told me that one.

 

Abalakov wikipedia link

[Weekend_Climberz]

One good tip that I picked up on making the actual holes, is to offset them vertically. Since the ice fractures horizontally, I suppose it would just makes sense to do this, but I had never heard of it until this season. Here's a good link with a photo:

 

http://www.planetfear.com/article_detail.asp?a_id=437

[Kevin_Matlock]

A cool trick that I've never tried, but supposedly works: Thread your rope directly through the V-thread to avoid having to leave any cord. Steve House told me that one.

 

Seems like a bitch when it's time to pull the rope!

[Alpinfox]

A cool trick that I've never tried, but supposedly works: Thread your rope directly through the V-thread to avoid having to leave any cord. Steve House told me that one.

 

Seems like a bitch when it's time to pull the rope!

 

That was my response too, but he said, "nope. works fine."

 

If I ever get around to trying this out, I plan to pull the rope back and forth a few times to smooth out the inside of the V, and then have the first rappeller do a test-pull before the second rappels.

[lummox]

use 22cm. tilt the holes so they fill with water then freeze (better for the next parties to use them).

[catbirdseat]

Putting the rope through your Vee Thread is essentially the same thing as making an ice bollard. I never had trouble pulling the rope on bollards.

 

One thing to consider is that if there is running water under the ice and it's getting colder, the rope could freeze into the ice. In that case, stay with the webbing.

 

I've had this happen with a top rope anchor I wanted to retreive. I had to chop it out, and in the end, put a knick in the cord.

[G-spotter]

I have rapped off an abalakov made with a 14cm stubby. It worked fine.

 

We tested an Abalakov by chipping away at the central ice with an ice tool. It held repeated two-person bounces down to about 5cm thick, then suddenly fractured.

 

It's been "new" since the early 90s in North America. The Russians invented it much earlier. '

 

I rarely rap off a double Abalakov unless I'm using a new one to back up an old one. Just leave a screw in for back-up till the last and lightest person comes down.

 

The vertical offset can be a good idea but sometimes with thin ice you have to use whatever works.

 

The big problem I find is that the longer the screw you use the harder it is to get the two holes to line up. If you only have a little bit of ice, or a bulge, you don't want to be drilling too many holes or else you will be rapping off Swiss cheese.

 

If you can avoid it don't drill an Abalakov in the outside part of a bulge - the ones that would dinnerplate off if you hit them with a tool will plate for other reasons too.

 

I find 6mm or 7mm cord, or the 9/16" webbing works the best.

 

On popular routes add a quick link or rap ring to the webbing cause someone else will be using the same anchor most likely.

[rhyang]

One trick for lining up the holes I was taught and have used a few times is after drilling the first hole, put another screw part way in to help with aligning the second hole.

[G-spotter]

It says that in all the books, but I don't think it works. The angle of the hole is determined with the first few turns, so if you fuck up the orientation of the second hole by more than a few degrees right at the start, you miss the first hole.

[rhyang]

Sorry to hear that I guess I have just been lucky ...

[Chad_A]

A trick that you can use with nylon webbing is folding an end into a v-shape and melting it into that shape permanently with a lighter (assuming you're making a piece or two to have on your harness before you're on the climb.) This helps your v-thread tool grab it a bit easier.

 

I have no problem rapping off an Abalakov made with 16cm screws, in good ice. I believe Craig Luebben's book has some good test info on v-threads; can't remember any numbers off the top of my head.

 

Not that I'd recommend it, but my pal had to retreat off a face in Peru a year or two ago with v-threads made with a 10cm stubby. Guess you take what you can get if the ice gets a bit sketchy.

[jmace]

One good tip that I picked up on making the actual holes, is to offset them vertically. Since the ice fractures horizontally, I suppose it would just makes sense to do this, but I had never heard of it until this season.

 

Pretty sure I asked Don Serl about this and he said not a good idea, although ice fractures horizontally once you have the holes ice is stronger width wise rather than vertical, something to do with the grain of the ice being vertical therefore easier to shear through.

 

From your picture maybe you mean just a little offset but dont go ahead and make them vertical

[Alex]

From my own experience...

 

I've read in some places that this is a "new" technique. Wondering how long this has been around and what the hell people did before.... leaver screws?

 

Its been around more than 20 years now. Before, people (in the Rockies at least) rapped off conduit.

 

Has anybody heard of someone ballsy enough to make one from a stubby?!?!?

 

Sure, I've even done that once or twice, but in those cases the ice is damn thin, you are desperate, and you make 2 or 3 Vthreads instead of 1.

 

if you run cord through it, how do you tie the ends: double fishermans? Some other mysterious "v-thread knot"?

 

double fish or euro-death.

 

these used only for pro -OR- for rapping? What about used for a top rope? Too sketchy to trust in an abusive TR scenario?

 

a properly drilled vthread in good ice is much stronger than an ice screw. So for TR-ing you could *easily* TR off two equalized v-threads in good ice, just as you would 2 or 3 screws.

 

do you "always" prepare 2 of them for redundancy or is this only for less-than-perfect ice; in other words if the ice allows, is it sometimes OK to rap off a single v-thread?

 

I was apprehensive the first time I rapped off a single vthread, which was heading down weeping wall....lots of exposure...to another hanging belay....but single threads are fine if the ice is good, and its your own cord you are leaving. cord degrades rapidly, so dont trust a single anchor if you didnt drill it yourself. That said, there are ALOT of vthreads that become established on Rockies trade routes that can last for several months of continuous use.

 

[dbconlin]

I always carry at least 1 22 cm screw for this purpose. While in good ice, shorter lengths may provide adequate v-threads, why not make the best. Especially since I usually commit my whole life to this single anchor and I have some reservations about doing that even in good ice with 22 cm holes.

 

I've usually used about 7mm cord. Sewn thin runners are sometimes easier to grab with the v-thread tool, but that gets pricey. I've tied cord with double fishermans.

 

I've only used them for rapping, but I could see it being a good way to top rope (2 threads equalized). I haven't placed for pro due to time/fatigue placing it.

 

I have usually used a single v-thread, if ice is good. If ice is sketch, I like to equalize 2, but you use 2-3 times as much cord/webbing.

 

Suprisingly, I have never had too much trouble aiming the second hole properly even with 22 cm screws.

 

Backing up with unweighted screw for first rappeller (perhaps heaviest) is definitely a good idea.

[jlamo]

Once when demonstrating VT to a group, I placed one near the ground and had everyone yard on it to demonstrate the strength. Well the cord busted, when I looked closely it appeared that it might have been cut. I don't know if it was a fluke, bad tat, or the ice was real brittle that day. My theory is that the edge of the ice where the two holes meet was so sharp it cut the cord.

 

Now I always grab the ends of the cord after I thread and before I tie it off and I floss it back and forth a couple of times to smooth things out in case there is a sharp edge where the two holes meet. I haven't had a failure since and that was probably 14 years ago...

[Dannible]

Does anyone know how much strength webbing and cord loses when it is frozen?

[Jens]

Does anyone know how much strength webbing and cord loses when it is frozen?

Great question. I'm curious to.

An engineer explained to me how vertical v-threads are worse than horizontal v-threads (he also was well versed in how ice fractures).

 

[G-spotter]

My theory is that the edge of the ice where the two holes meet was so sharp it cut the cord.

 

Now I always grab the ends of the cord after I thread and before I tie it off and I floss it back and forth a couple of times to smooth things out in case there is a sharp edge where the two holes meet. I haven't had a failure since and that was probably 14 years ago...

 

Ice melts under pressure.. a sharp edge in ice cannot cut cord because the cord will melt it into a blunt edge. Probably your tat was bunk or something.

[catbirdseat]

Does anyone know how much strength webbing and cord loses when it is frozen?

Great question. I'm curious to.

An engineer explained to me how vertical v-threads are worse than horizontal v-threads (he also was well versed in how ice fractures).

If the cord is saturated with water, and frozen, expect it to lose some of its strength. Under normal circumstances, cord and webbing, is able to flatten out when it is tensioned around an edge. This tends to equalize the load share between the various fibers. A frozen cord can't do this because it can't flatten. Consequently, the outside fibers will take more strain than the inside ones. How much strength loss is anyone's guess.

[G-spotter]

Enginering research at UBC in the 1980's found that when webbing was wetted and frozen it lost up to 1/3 or more of its strength. Interestingly when wetted, frozen webbing as dried out, the dry webbing after was statistically slightly stronger than before it was wetted/frozen.