Threads?

I was reading about the Dolomites and noticed a few places bring up "threads". Looking into this further, it seems that some climbers carry lengths of stiff kevlar cord in the Dolomites for pushing through loops in the rock.

Thinking about it, I run into this situation somewhat frequently--either loops in the rock, chocks, or simply boulders that have fallen together that leave gaps. These have the potential to be some of the most solid protection possible. What I usually do is sling a dyneema alpine draw around it, clipping both carabiners to the rope. There are a few problems with my approach however:

1. Abrasion on my alpine draws.
2. Threading a bight of dyneema through small gaps can be tricky--something stiffer and narrower would be easier. I try to use the bartacked section of my sling in such cases.
3. Followers sometimes have trouble cleaning these because the individual threads of dyneema tend to get caught on rough rock. Again something stiffer and narrower would help here.

I was thinking (probably overthinking) that there might be some wisdom in the Dolomites climbers' using kevlar cord. A 50cm length of 5mm kevlar cord with figure 8 follow through loops on either end is stiffer, narrower, and lighter than a dyneema sling: you just run it around the feature, girth hitch one end through the loop and clip that to the rope (the girth hitch avoids tri-loading the carabiner). I run into these situations about as often as I run into any one of cam, so it makes sense to carry a cheaper, lighter piece of gear to deal with that situation.

What are people's thoughts? Has anyone used something similar?

Note how he clips both sides of the sling to one carabiner. This is great for this situation because the feature he's clipping to is very narrow, but if the feature were wider this might put a tri-directional load on the carabiner (this is why I usually end up clipping two separate carabiners).

I haven't tried this, so not sure I have anything of value to add, but...

- Wouldn't the knots on the end of the cord make it difficult to thread? Tying it while at a stance doesn't seem like a good option, so you'd need something pre-rigged.

- Kevlar cord is slippery shit. You'll need a non-Kevlar sheath to make it knotable. Alternatively, you could use a piece of 12-strand spectra with eye splices on the ends. This would eliminate the knots, any risk of knots slipping, and stiffen the cord a bit more.

- It sounds like you want something stiff, short, strong for its thickness, and abrasion resistant. A short piece of wire swaged much like a funkness device (but with a higher working load) may be a better option? That said, repeated falls on a cable is probably a pretty quick way to eventually destroy the rock tunnel.

- If you're willing to accept a girth hitch on the Kevlar cord, you could do the same on a dyneema sling, so I'm not sure there's an advantage there. That said, we all know the issues with girth hitches, and your other points in favor of this approach still stand.

Still, I dig the idea. Slinging narrow natural anchors with slings has never been my favorite.

About the issues with grith hitching, what if you just had the kevlar tied in a loop and instead of girth hitching clipping both ends individually with 1 biner each? You wouldn't have the tri-axial loading issues nor would you have the girth hitching issues. Am I missing something blatently obvious that would cause failure?

The only potential issue I can think of at the moment is that the sling/cord would shift a few mm before catching which could cause abrasion issues on really sharp rock. But for rock that isn't super sharp, I'd imagine it would be fine with a very abrasion resistant material such as kevlar

eli poss wrote:

About the issues with grith hitching, what if you just had the kevlar tied in a loop and instead of girth hitching clipping both ends individually with 1 biner each? You wouldn't have the tri-axial loading issues nor would you have the girth hitching issues. Am I missing something blatently obvious...?

The "obvious" thing you're missing is that OP said exactly this in his second (now his first; apparently he did some editing) post.

What the fuzz are y'all talking about?

Clip and go

Threads are Tradtastic!

Gunkiemike wrote:

The "obvious" thing you're missing is that OP said exactly this in his second post.

Nope. The OP talked about using a basket hitch, clipping a biner to both ends of the loop and to the rope. I'm talking about clipping one end of the loop to the rope with 1 biner and clipping the other end of the loop to the rope with another biner.

Edit to add photos:

This is what the OP is talking about, a basket hitch

This is what I'm talking about

That's a girth hitch at the top. I extended the tail to cinch up the rope so I could reasonably fit in th the picture--I hope that doesn't make the picture too confusing.

David Kerkeslager wrote:

That's a girth hitch at the top. I extended the tail to cinch up the rope so I could reasonably fit in th the picture--I hope that doesn't make the picture too confusing.

You may want to do some research on the strength efficiency for fig 8s and girth hitches in kevlar. As far as I know kevlar, like all aramid textiles, does very poorly with knots. In technora, a blend of spectra and aramid, you get somewhere around 40% efficiency with a figure 8. Keep in mind the fig 8 is more strength efficient than a girth hitch. 

Not saying it won't work for you, just something you may want to look into before you go whipping.

I'd be more concerned about what that knot is going to do to high-mod cordage like Kevlar (40% of original strength for a figure eight), and less concerned about the loading on the biner. (80% strength at up to 60 degrees of tri-loading.) That picture of the girth hitched figure-8 kevlar eye is sketch - it puts the weak spot of the figure eight knot, and the weak spot of the girth hitch in the same place. 

Eye splices on spectra was my first thought too. Brummel splices on 3/16" Amsteel Blue or similar. 

Or just buy the ones they use in Europe, if you are really interested in this technique: https://www.dicksclimbing.com/products/edelrid-aramid-cord-sling-6mm?variant=14319303111

About $10 for the 60 cm or $15 for the 120 cm...shipping about doubles the cost though...I get just shy of $50 total shipped for one 60 and one 120 from Dicks after all the VAT math is done.  If you climb trad on sharp limestone a lot (maybe you folks on the Niagara escarpment?), it might be worth it. 

eli poss wrote:

You may want to do some research on the strength efficiency for fig 8s and girth hitches in kevlar. As far as I know kevlar, like all aramid textiles, does very poorly with knots. In technora, a blend of spectra and aramid, you get somewhere around 40% efficiency with a figure 8. Keep in mind the fig 8 is more strength efficient than a girth hitch. 

Not saying it won't work for you, just something you may want to look into before you go whipping.

Yeah, I'm definitely concerned about the knots slipping. The girth hitch is just the knot that seems most easy to tie from a stance, but it's definitely not ideal as far as strength. I was hoping to make up for this with stronger material, but if the figure 8 slips, it's a moot point.

Nick Hatch wrote:

I'd be more concerned about what that knot is going to do to high-mod cordage like Kevlar (40% of original strength for a figure eight), and less concerned about the loading on the biner. (80% strength at up to 60 degrees of tri-loading.) That picture of the girth hitched figure-8 kevlar eye is sketch - it puts the weak spot of the figure eight knot, and the weak spot of the girth hitch in the same place. 

Eye splices on spectra was my first thought too. Brummel splices on 3/16" Amsteel Blue or similar. 

The 80% number for tri-loading surprises me--80% of 22kN is still stronger than the holding strength of many of my cams, so I'd actually feel pretty good about that. Do you have a source for that number?

It looks like Amsteel Blue makes a eye-spliced product, but it's 25' long. I wonder if they would do a custom 2' one...

Xam wrote:

Or just buy the ones they use in Europe, if you are really interested in this technique: https://www.dicksclimbing.com/products/edelrid-aramid-cord-sling-6mm?variant=14319303111

About $10 for the 60 cm or $15 for the 120 cm...shipping about doubles the cost though...I get just shy of $50 total shipped for one 60 and one 120 from Dicks after all the VAT math is done.  If you climb trad on sharp limestone a lot (maybe you folks on the Niagara escarpment?), it might be worth it. 

I'm definitely interested. But how do they use these in Europe? I can think of three possibilities I'd be interested in exploring:

1. Looped through the feature one carabiner on each end attached to the rope (this is what I currently do with dyneema slings). This improves over dyneema because of the stiffness and abrasion resistance, but the problem here is that you have to remove one carabiner, thread the loop through, reclip the carabiner, and then clip both carabiners to the rope. That's a lot to do with one hand from a stance.
2. Girth hitch the feature and carabiner the other end to the rope. This is fast and easy but the girth hitch significantly weakens the system.
3. Basket hitch the feature with one carabiner to attach to the rope. In some cases this can introduce triaxial loading on the carabiner, but if the 80% figure quoted above is correct, I'm leaning toward this as a solution.

eli poss wrote:

Nope. The OP talked about using a basket hitch, clipping a biner to both ends of the loop and to the rope. I'm talking about clipping one end of the loop to the rope with 1 biner and clipping the other end of the loop to the rope with another biner.

Edit to add photos:

This is what the OP is talking about, a basket hitch

This is what I'm talking about

What you're talking about is not inconsistent with what OP said ("What I usually do is sling a dyneema alpine draw around it, clipping both carabiners to the rope.") It's a basket whether there's one biner or two, or whether two biners are on the sling ends separately or together.

But this is all just semantics. It's a fine way to go in the situation described.  

David Kerkeslager wrote:

What advantage does this offer over a basket-hitched sling?  The knotted ends will be more difficult to push through any constrictions.  And as discussed, there are strength giveaways.

Yates used to make a "stiffy runner" (not their name for it) that was a rabbit runner with a semi-stiff section.  It was the bee's knees for threads.  I still use something like it ice climbing, and love it for threading behind pillars and through the ocasional manufactured tunnel.

David Kerkeslager wrote:

The 80% number for tri-loading surprises me--80% of 22kN is still stronger than the holding strength of many of my cams, so I'd actually feel pretty good about that. Do you have a source for that number?

It looks like Amsteel Blue makes a eye-spliced product, but it's 25' long. I wonder if they would do a custom 2' one...

David, I can splice one for you gratis, but my work would come without a warranty and without any guarantee that you won't die while using it. But fwiw, I'm fairly confident in my splicing. Eyesplices in 12-strand are about as easy as splicing gets, so you could definitely do it yourself if you're interested. You don't need anything more specialized than a piece of wire.

David Kerkeslager wrote:

I'm definitely interested. But how do they use these in Europe? I can think of three possibilities I'd be interested in exploring:

1. Looped through the feature one carabiner on each end attached to the rope (this is what I currently do with dyneema slings). This improves over dyneema because of the stiffness and abrasion resistance, but the problem here is that you have to remove one carabiner, thread the loop through, reclip the carabiner, and then clip both carabiners to the rope. That's a lot to do with one hand from a stance.
2. Girth hitch the feature and carabiner the other end to the rope. This is fast and easy but the girth hitch significantly weakens the system.
3. Basket hitch the feature with one carabiner to attach to the rope. In some cases this can introduce triaxial loading on the carabiner, but if the 80% figure quoted above is correct, I'm leaning toward this as a solution

Girth or basket is fine and complimentary.  For a thin thread use a basket.  For a thick thread, where the basket would introduce a triaxial load on the carabiner, use a girth....if positioned correctly, the fabric on fabric part of the girth is barely loaded and most of the load is on the rock similar to a tensionless hitch. 

Gunkiemike wrote:

What advantage does this offer over a basket-hitched sling?  The knotted ends will be more difficult to push through any constrictions.  And as discussed, there are strength giveaways.

Yates used to make a "stiffy runner" (not their name for it) that was a rabbit runner with a semi-stiff section.  It was the bee's knees for threads.  I still use something like it ice climbing, and love it for threading behind pillars and through the ocasional manufactured tunnel.

Yeah, I was hoping to avoid extra material with the knots, but I'm persuaded that the bulky-ness of it isn't worth it.

What's the runner you use for ice climbing?

Mark Berenblum wrote:

David, I can splice one for you gratis, but my work would come without a warranty and without any guarantee that you won't die while using it. But fwiw, I'm fairly confident in my splicing. Eyesplices in 12-strand are about as easy as splicing gets, so you could definitely do it yourself if you're interested. You don't need anything more specialized than a piece of wire.

I'll take you up on that, and I'm happy to Venmo you money for the materials. I promise to take pictures and post them!