Girth hitching slings?

I bought and read Climbing Anchors 2nd ed by John Long and Bob Gaines.
I was reading and they said something along the lines of girth hitching two slings together to get a longer sling. I don't have any of my BD sling's manuals handy, but don't slings lose close to half of their strength when girth hitched? Has anyone had a sling fail when girthed, or consistently use this technique with no problems?

Yes they lose a lot (~50%) of strength depending on the type (nylon to nylon, nylon to dyneema etc). Don't do it unless you have to. You will rarely if ever have to.

Black Diamond QC Lab Girth Hitch Testing

The above link has a lot of information about girth hitching slings together, well worth the read.

I girth hitch 1" webbing frequently to set up top-rope anchors, but I'd be scared to do that with slings in situations where lead falls might occur.

things have changed slightly since then—thinner and thinner webbing is now on the market. We would repeat some of his tests, and add some new ones to the mix.

This is from the link posted above. I wonder what year the edition you are reading was published. I have a version that's about 18 years old, so most of the the slings there would be pretty wide nylon ones, which could have much different characteristics from the "thinner and thinner" webbing in use today.

I enjoyed that book and learned a lot from it, but like much else int he world it's pretty amazing how much the technology has changed.

All climbing soft goods are compromised 35% to 65% from their original strength when you knot it or hitch it including the rope you tie in with . Rather than saying something like "never" I find it best to understand the limitations of your gear and what is the current application.

For example, a sling rated @ 22kn when girth hitched may break at 11kn (almost 2500 lbs). This may be totally fine to girth hitch your harness for cleaning anchors and clipping anchors while doing multiple rappels. Girth hitching something that may be subject to a leader fall is much less desirable.

11kn is still stronger than many pieces on a typical trad rack. I'm not suggesting you should or shouldn't girth hitch your slings. What it boils down to, know the limitations of your gear and make sounds judgements.

Greg said it well.

ANY knot or hitch reduces the strength of your rope/webbing.

If you find yourself hitching together slings all the time, you probably need some longer slings. It is always best to have the fewest failure points in your system.

Also, the point about the type of sling being important is prudent.

That said, I would(and do) bet my life on the fact that hitched slings are strong enough for not shock loading situations. Also, anytime you hitch a sling to your harness, you're essentially hitching sling to sling, and we all do this.

Greg D wrote: Rather than saying something like "never" I find it best to understand the limitations of your gear and what is the current application.

NEVER use H2SO4 to clean your rope and slings; even if intended as a rope rug or other decor; you can hurt your puppy and that's bad....

Interesting discussion. The conclusion recommends joining slings with a carbiner vice girth-hitch (etc), but I wonder about that. I use the old-school thick nylon slings, and I "girth-hitch" them (technically a strop-bend I guess), which means they should perform at ~80% of static strengh (~18KN) or ~14kN in dynamic situations.

The gate open strength of a neutrino is 8kN by comparison. Of course, with a wire gate biner there is theoretically less chance of a gate vibrating open during a fall, but generally double slings are used in situations where the sling, etc will contact the rock, so there's always a chance that the gate could be forced open.

I probably should also point out that the 8kN figure is probably a 3-sigma value (=> conservative), and the data provided by Kevin is clearly not.

Intuitively, I feel more comfortable with the strop bend, but maybe I'm wrong.

Greg D wrote:All climbing soft goods are compromised 35% to 65% from their original strength when you knot it or hitch it including the rope you tie in with . Rather than saying something like "never" I find it best to understand the limitations of your gear and what is the current application. For example, a sling rated @ 22kn when girth hitched may break at 11kn (almost 2500 lbs). This may be totally fine to girth hitch your harness for cleaning anchors and clipping anchors while doing multiple rappels. Girth hitching something that may be subject to a leader fall is much less desirable. 11kn is still stronger than many pieces on a typical trad rack. I'm not suggesting you should or shouldn't girth hitch your slings. What it boils down to, know the limitations of your gear and make sounds judgements.

For the record, any response like this one that takes logic and analytical thought into consideration will automatically get a +1 in my book.

Thanks

I've only done it on belay anchors and for TR'ing. Maybe I've been lucky at the belay, but I've never had an issue. I wouldn't do it on lead. I generally carry 2 double length runners just in case I need to extend.
Good info.

Mark Nelson wrote: NEVER use H2SO4 to clean your rope and slings; even if intended as a rope rug or other decor; you can hurt your puppy and that's bad....

I knew someone would poke a hole in my statement. I should have known it would have been you. Thanks Mark.

I suppose you should avoid making a habit of it, but I wouldn't lose sleep over it either. Kind of like drinking mass-produced pale lagers...

Greg D wrote: I knew someone would poke a hole in my statement. I should have known it would have been you. Thanks Mark.

Okay okay, you can kinda toss the rope on your neighbor's cat or poodle. Don't worry, it's like a cleanser for these species.

I don't know why, exactly, but there it is.

Anyway, I generally go for like to like materials, but try not to girth as a standard practice. Though in a pinch I did girth a nut cable with spectra, as well as screws, chalks, & pitons; they were all I had & needed to be done.

Mark Nelson wrote: Okay okay, you can kinda toss the rope on your neighbor's cat or poodle. Don't worry, it's like a cleanser for these species. I don't know why, exactly, but there it is. Anyway, I generally go for like to like materials, but try not to girth as a standard practice. Though in a pinch I did girth a nut cable with spectra, as well as screws, chalks, & pitons; they were all I had & needed to be done.

Agreed. A girth hitched, rusty piton is better than no piece at all!

Mark Nelson wrote: Okay okay, you can kinda toss the rope on your neighbor's cat or poodle. Don't worry, it's like a cleanser for these species. I don't know why, exactly, but there it is. Anyway, I generally go for like to like materials, but try not to girth as a standard practice. Though in a pinch I did girth a nut cable with spectra, as well as screws, chalks, & pitons; they were all I had & needed to be done.

I don't remember where I read about it, but I'm virtually certain I can recall an accident where a climber girth hitched a sling right through the cable of a stopper (Ostensibly because he was either out of biners or simply trying to conserve them) and when he fell on that piece, the stopper cable sliced right through the sling like butter and the climber decked.

I would much prefer girth hitching 2 slings together over a sling to a nut.

So what about the British cams that have the extendable slings? They must test those when they get their kn rating right? I know they are not girth hitched but there must be similarities. What about girth hitching the thumb loop on a BD C4? Its a smooth surface and fairly thick, much thicker and smoother than the cable on a nut.

One good tip also...is never girth hitch a "modern" skinny dyneema runner through a standard thicker sling. The Dyneema one can slice through the other like butter.

I've seen it with my own eyes.....be careful out there.

I agree it should be avoided, but relative to many other things, it is not that unsafe. Even at 50% reduction, 22 kn slings girth hitched together is still ~10 kN, i.e. as strong as a hefty stopper. How many of us freak out over a 10kN stopper rating?

So when possible it is better to chain things together with biners, but I really would never chew a partner out for building an anchor with girth hitched slings, unless it was a habitual thing. I would not freak out taking a whipper on a girth hitched sling off of pro either.

I guess I would call girth hitching a party foul, but no worse.

Moof wrote:I agree it should be avoided, but relative to many other things, it is not that unsafe. Even at 50% reduction, 22 kn slings girth hitched together is still ~10 kN, i.e. as strong as a hefty stopper. How many of us freak out over a 10kN stopper rating? So when possible it is better to chain things together with biners, but I really would never chew a partner out for building an anchor with girth hitched slings, unless it was a habitual thing. I would not freak out taking a whipper on a girth hitched sling off of pro either. I guess I would call girth hitching a party foul, but no worse.

It's much easier to shock load a long dynema sling than a nut. -2 cents

It seems that over time as more "safety data" is released climbers have become increasingly paranoid of potentially catastrophic actions like this one. Until maybe 10 years ago a large part of many climbers slings were tied 1" tubular webbing, which most likely had strength in the 10-15kN range. Now that we mostly use sewn runners the idea of reducing strength to this level by girth hitching slings is somehow a bad idea.

There is also this misconception that dyneema slings are as static as steel cable, this is simply not true. To prove this to yourself girth hitch two dyneema slings to your hammer and attempt to use this as a funkness device. Once your arm is numb, switch out for a real funkness and feel the difference.

I have had the opportunity to use skinny dyneema slings for all sorts of non-approved activities. From building a raft to cross the Gunnison River, as a makeshift funkness and even 'gasp' taking whippers onto girth hitched stoppers. The only damage I have seen to them came from abrasion from rocks or snags from my fingernails. I do retire them sooner than nylon slings, but that is for my own piece of mind.

My point is that while girth-hitching two slings together may decrease the strength of both it is sometimes the safest option. I would rather have two girth hitched slings than a cross loaded carabiner. I would rather girth hitch a stopper than clip in directly and have heinous rope drag. I would rather climb with a light rack and have to sometimes improvise than have tons of gear to "protect" me in every possible scenario.

I think it is important to understand the weaknesses of your system, but more important is to know what that weakness really means.