v threading poor ice

I seek some info on the art of v threading. Recently, having to bail off some routes due to poor ice conditions it got me thinking about different aspects and techniques involved. There was a setup just above me where somebody, also bailing, set up two v threads side by side about 2 ft apart. Our party repelled on a single v thread. It got me thinking: is two really helpful? Should they be on the same level, and how far apart? Opinions?
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Also, did anybody ever try to do a German buttress thread? It could be potentially used in cases of thinner blue ice. Not sure how ice would behave in those cases. Doesn't hurt to look into it I suppose.

I have nothing constructive to contribute, I would just like to point out it's "rappelled". Pet peeve. Carry on.

Never had to rap off a thread but I'm pretty sure if you are doing multiple they preferably should be at different heights

neve wrote: Non constructive contributions is my pet peeve.

Then you probably came to the wrong place.

Generally speaking though, if you're going to bother spending the time to make 2 threads, they should be above each other, not side by side. Make sure to use a longer length of cord on the upper thread so that it has some measure of equalization with the lower thread. The upper thread should be at least 1 foot higher than the lower thread.

Or, save time. Back up the thread with a single screw placed high and a long sling down to the "master point." Make sure the screw isn't actually holding any weight. The heaviest parties rap first with the screw backup. The last climber to rap (also hopefully the lightest) then pulls the screw and raps on the tested/confirmed thread.

If I ever start having doubts of the strength of a V-Thread I remind myself of this video:
m.youtube.com/watch?v=hz0v-…

If you haven't personally done this test for yourself, I highly recommend it. Also, as stated above, IF you still find it necessary to make two threads be sure that they are placed vertically apart. Ice fractures horizontally...thought that was common knowledge.

-Mac

You're confused. There are two types of threads. V-threads and A-threads. In a V-thread (also known as an Abalakov) the two holes are drilled side by side. In an A-thread, the holes drilled one above each other.

Assuming you want to create a rappel anchor that uses two threads, the two THREADS should be above each other, regardless of what direction you drill the holes for each individual thread.

What do you mean by "tuna fish hooks?" Maybe FISH hooks? No one uses them for ice climbing anchors. At least they shouldn't be.

God dammit, I think I'm getting Hellenored.

Jon H wrote:You're confused. There are two types of threads. V-threads and A-threads. In a V-thread (also known as an Abalakov) the two holes are drilled side by side. In an A-thread, the holes drilled one above each other. Assuming you want to create a rappel anchor that uses two threads, the two THREADS should be above each other, regardless of what direction you drill the holes for each individual thread. What do you mean by "tuna fish hooks?" Maybe FISH hooks? No one uses them for ice climbing anchors. At least they shouldn't be. God dammit, I think I'm getting Hellenored.

The station
BTW I'm not confused. A thread is essentially a vertical v thread.
Did you give German buttress thread any thought?
A. V thread. B. GO thread. C. A thread.
I named German buttress thread "GO thread" .

Does anybody think that angle would work better on thin ice? 1st screw goes perpendicular, second goes at 45 degree. I like drilling my V threads and A threads respectfully at 60 degrees whenever possible.

What's a german buttress thread? Never heard of one outside of industrial machining applications?

These discussions about the theoretical strength of horizontal vs vertical Abalakov threads are all very interesting but for practical purposes I don't think it makes any difference. I did a quick seach of ANAM and there's not a single report of a properly-tied Abalakov having failed in practice, regardless of orientation. All the reported accidents involving ice rappels had much more mundane causes - ropes not threaded through anchors, rappel devices not attached to ropes, people rappelling off the end of the ropes, etc. The only reported accidents involving anchor failures dated back to the days when people used to rappel off conduit piping inserted into ice-screw drill-holes.

As Jon H said, better to save time and effort by using an ice-screw as a back-up anchor and removing it when the last person rappels. In practice you're probably going to be anchored off an ice-screw anyway before you start building an Abalakov.

As a rap anchor, the orientation really doesn't matter.
The reason for looking at the A-thread was to test if a comparative difference exists using either to take a belay hit. The A-thread showed a more consistent & higher strength position in holding the energy.

In either case, using good ice. Also tested lake ice & glacial ice.

Asking about crappy ice is basically the same as asking about shit rock. What i see here in the OP is probably good ice that is mistaken for not good.

But really, if you have to ask about shit ice, why not move to another position that has better ice?

I have rapped off several V Threads...

I always make two V Threads one above the other.. ice tends to sheer horizontally

Gotta agree with what Mac said, try it for yourself and you'll be amazed. Backing up a thread with a screw for the first person off is a great way to add some extra confidence to the rap as well.

An "A" thread (Anderson thread) is NOT a vertical "V" ("Abalokov thread").

As someone correctly mentioned, ice tends to fracture horizontally and while it is true that most have never heard of an "V" thread breaking (the thread itself, the knot or the ice) it is possible for the "V" thread to fail if not constructed properly (bad ice, too shallow, holes too close together, melting out). A "V" thread will also melt out faster if the rappel rope is weighted for X period of time, i.e. the belayer gets hung up for some reason; the main reason is obvious: the thread has a smaller diameter.

The Anderson ("A") thread, on the other hand has a number of advantages. Easier to drill the holes (some would argue this, like me) because vertical line of sight is easier than horizontal line of sight (but I won't argue the point: depends on where the climber is in lining up the holes). Someone also mentioned that an "A" thread is stronger: no doubt...and has been tested, however, since even "V"s tend not to fail, perhaps it's moot (however, this depends on ice quality).

The drawing is complicated but the task is easy. Drill one hole downwards (doesn't matter if you use the same length screw) and another upwards, however, take care to make the lower screw hole longer.

Three advantages to the "A": one doesn't have to use cord to thread the holes....simply thread the rope end down and out the bottom hole. Some complain that it's hard to thread the "turn", i.e., where the holes meet. This problem is no different than a "V" thread and can be dealt with two ways: a candela (or similar), or other hooked device to grab the end & pull. But the best way to deal with this is to put a rubber ice screw cap over the end of the "push" end. If built properly, it will glide right through. Then, floss back and for a bit to round the turn -- will explain what this does in a minute.

Second advantage: the "A" will not melt out as quickly and in poor ice, it's the anchor of choice anyway. The climbing rope has a thicker diameter.

Third advantage is after rappelling, simply pull the rope (the side exiting the BOTTOM hole) and it should slither down. No need to leave a biner on a "V" thread or pull (read: 'saw') the rope across your 6 ml "V" thread. Flossing the screw junction makes the pull very easy.

As with "V"s, two "A"s should be placed, one above the other (bottom hole of top one at least 12" or more above the bottom thread (top-most hole). Some very slightly off-set the vertical alignment (by 2" or so). Tests show this to be stronger, however, since most threads don't fail, maybe it's moot. If using two "A"s, you should floss the upper hole of the bottom thread, depending on how you think the rope will pull through.

This is sometimes referred to as the "Threadless Thread". To emphasize, if built properly, the rope pulls like a greased pig. (If using two ropes, MAKE SURE the knot is below the the exit hole of the bottom thread, otherwise, you'll be pulling (usually unsuccessfully) the rope across the top-most hole -- a lot of friction).

If you practice this from the deck and get good at it, you won't build another "V" thread: the "A" has too many advantages over "V's" and is actually much faster to construct.

An "Anderson" thread

^^^brilliant!

Just chip a bollard.

neve wrote: I like drilling my V threads and A threads respectfully at 60 degrees whenever possible.

If you are constructing "A's" and drilling both holes at 60 degrees (or the same angle, doesn't matter), you are not properly doing it. If the angles are the same, you are defeating one of the many advantages of "A's": pulling the rope. But I don't think you are threading the rope -- you are threading the holes with 6-8 ml cord and still creating a problem.

Assuming you are threading the holes with cord, you are placing greater pressure on the ice (at the 'back turn' as well as the top-most hole where the rope or cord is threaded) than a properly constructed "A" would, thus increasing the chances of it melting out. Think about it.....it's pretty simple physics. I know novices & experts who at one time(s) in their ice career got hung up for one of a zillion reasons and were either hanging in space (not so common) or putting a lot of pressure on the ice above by weighting the rope because they had to stop the rappel. I need not list the many reasons you might end up putting too much pressure FOR TOO LONG A TIME on the anchor above. Remember, ice is not a solid (in pure physics terms), rather, it's WATER (a liquid) w/o a lot of heat in it; by stressing it, you are turning the ice into water. One of the axioms of physics is "ice flows under pressure".

Depending on the length of screws (and surface features of the ice), a downward angle of 60 degrees is fairly shallow. 50 degrees down and 60 degrees up is better, stronger and will hugely facilitate the rope pull. Additionally, drilling both at the same angle makes "flossing" the inner joining angle much more difficult. Try to keep at least a 10 degree difference in the two angles. If the screws bottom out, I'd still take a shallow "A" over a "V": both will bottom out, however, the A is stronger. (I've also been in a position where I've had to use a combination: "A" and a "V" -- a bit tricky if you want to use the 'rope pull'). Without the proper angles, regardless of whether you are using the "rope pull", the thinner 6-8 ml cord you are probably using is much more prone to melt into (hopefully not through) the ice with equal angle drilling.

A threads
Here is me experimenting on some Montana ice. I can see how the straight in screw on top and the slanted on bottom would be better.
Despite seemingly small surface between the holes the threads went in fairly deep so most volume of ice came from deeper layers.

Nerd- you've drilled your screw holes far too close together. I'm not talking about the distance between your threads, but the individual In/OUT screw holes of the individual threads.

Warbonnet, thank you for the detailed and clear explanations.

Warbonnet wrote: Think about it.....it's pretty simple physics. I know novices & experts who at one time(s) in their ice career got hung up for one of a zillion reasons and were either hanging in space (not so common) or putting a lot of pressure on the ice above by weighting the rope because they had to stop the rappel. I need not list the many reasons you might end up putting too much pressure FOR TOO LONG A TIME on the anchor above. Remember, ice is not a solid (in pure physics terms), rather, it's WATER (a liquid) w/o a lot of heat in it; by stressing it, you are turning the ice into water. One of the axioms of physics is "ice flows under pressure".

I have no reason to disagree with the technique but the above explanation makes my heart hurt. So please indulge me as I try to present an alternate one.

Much of the interesting and useful properties of ice are due to the physics not being so straight forward. Water is one of the few substances that expands in volume as it changes state from water (fluid) to ice (solid). Putting local pressure on the ice, as with a loaded rope or cord, causes the locally loaded ice to compress and the process to work in reverse. This causes the ice to change back from solid to liquid. Under the pressure, the liquid water then moves to the side out from under the rope and rope moves down. Under enough constant pressure, the process is continuous and rope 'melts' through the ice. It makes sense that thinner cord would melt out faster under the same load as fatter rope since the local pressure on the ice is higher.

nerd2 wrote: I can see how the straight in screw on top and the slanted on bottom would be better. Despite seemingly small surface between the holes the threads went in fairly deep so most volume of ice came from deeper layers.

Nerd2: Good start......you have the basic idea. Not sure what you meant by the "straight in screw on top and the slanted on bottom.......". BOTH screws are slanted, the top-most being about 50 degrees downward (depending on ice conditions, etc.) If you drill the top-most hole horizontal, you've created two problems (one theoretical, the other practical). If you are using only the rope to rappel from (and not wasting time & cord to thread the "A", it will make the rope pull much harder. The theoretical part is that you might be putting too much pressure on the "horizontal ice" on the first hole drilled which will in turn affect it. I'd have to think about that -- not sure. The biggest downside is you are, w/o question, making the rope pull more difficult.

John H. is correct: holes too close but if you were 'experimenting', you are forgiven, however, it's a bit of a dicey set up. But good for you that you've played around with it.

The other thing that could be improved (I didn't include it in my post because it would have even been more complicated) is depicted in the drawing below. Rather than use two threads, one long cord can be used to "weave" through all 4 holes (in fact, that's how I do "A's).

Before I attach the "weaving" drawing, I'll add this: don't know how many of you have had to climb back up the rope (many ways to do this, inc. even re-climbing it, if possible & your belayer has access to one end......but this gets complicated so don't respond to this part.......am getting off track. I don't know many climbers, esp. very experienced ones who have not had to climb back UP the rope(s). Many things can result in this: the way down is NOT the way you wanted or should go....maybe it's super overhanging & you & buddy(s) are not up for that. And with all good intentions and properly built "A" to "Z" configurations, the rope gets stuck on the pull. (I've had this happen to me when my buddy -- a good ice climber -- pulled on the wrong end on an "A" wherein the knot was placed such that it had to be pulled thru the first hole (essentially impossible).

But he pulled so hard the knot was stuck. When we tried to pull the proper strand (the one exiting the lower, longer hole, it wouldn't go. So, back up the rope(s) he went. Can't recall what he used: 1 prusik, two minm-traxions.....sorry, I don't remember. For anyone trying to get back up ice ropes, you know how difficult this can be. (Should be practiced from the deck & make sure your ropes are icey: bury them in the snow until they are iced up). Skinnies are different than thicker ones in that they both present problems.

After things were fixed and he rapped down, the first thing he said was that he was worrying about the "A" melting through. I assured him it wasn't doing so because it was too bomber. But the thought, in theory, is a good one. NOW, think about that laborious, time-consuming job on a "V" thread(s). I would hate it, all things being equal (ice quality, V's spaced properly. An "A" will let you climb up (guaranteed pressure on the rope, maybe episodically but the "A" just took 2 ripplers DOWN and now the ice needs to hang in there for another one (or BOTH) to go up. I would take 2 "A's" anyway in this situation.

(Not sure what Xam is saying: are you suggesting that the thicker climbing rope will also melt through? All things being equal, it might do so but in the Jurassic. Are you suggesting the melting ice will freeze the rope (if doing a rope pull) such that it would be hard to pull? Not the case.

I'll work up a good, detailed drawing & post it in a minute.

(Basically, we're going to eliminate Nerd2's two knots & make them one, however, he's got the idea (with the caveat that the holes need to further apart & top hole drill at downwards angle).

Be right back.