Belay Loop Issues

[korup]

Dru, do you have a ref to AiNAM for that? I'd love to read the analysis...

 

Drew

[Dru]

I can't remember if it was in ANAM or a european publication, I just remember the scary picture.

[fern]

I think it was in High or similar british mag

[Jason_Martin]

JM,

 

So, if you don't have a belay loop on your harness (e.g., BD Alpine Bod), is it better to just belay the way the manufacturer intended, or to belay off your tie-in loop? For the Alpine Bod, BD recommends belaying with a locking biner through the crotch and waist straps of the harness. Is belaying off the tie-in loop inherently safer?

 

All the new alpine bods DO have a belay loop because of tri-directional loading on the biner. My recommendation is to do exactly what the manufacturer recommends. Do what the instructions that come with the harness tell you to do. If you have an old school bod harness and you are doing a lot of technical climbing, you should consider buying a new one with a belay loop.

 

Jason

[knotzen]

I just bought a BD Alpine Bod harness, three weeks ago, and it does not have a belay loop. You have to thread your pearabiner between the crotch loop and waist belt.

 

 

It's really hard to keep the belay device from cross-loading the carabiner opening because you have to belay straight up on the top of the biner, when the tendency is for it to slip down, facing out. Turning the pearabiner around means the lock is rubbin up against your shirt, not good either.

 

Not sure I'm going to stick with it. I love the snap leg loops, though. That's why I bought it.

[Stephen_Ramsey]

JM,

 

Thanks, that makes sense. The Trango Mountain harness is looking like a good bet-- 9 ounces, and it has a belay loop.

 

Cheers,

Steve Ramsey

[Dechristo]

I just bought a BD Alpine Bod harness, three weeks ago...

 

I own a BD Bod...

 

...it's a nut-masher.

[mattp]

Some of my buddies who do a lot hof hang time swear by their alpine bod harnesses. I think it depends on how it fits your body.

[Thinker]

Here's another possible solution

[Dru]

won't prevent triaxial loading if clipped to leg and waist, though.

[snoboy]

When you clip an HMS biner into a belay loop, the slots in the attached belay device end up running vertically, not an ideal position in my experience.

 

All of the other very interesting banter aside, this is an interesting point.

 

I actually like my belay loop, because it orients the slots in my belay device in a vertical position, an ideal position in my experience.

 

I climbed for years with a BD Alpine Bod, and found it quite comfy.

 

Jason Martin:

Almost all harnesses on the market now come with belay loops. Even the black diamond bod harness now comes with one.

 

I think that JM may be slightly mistaken about all the new Bod harnesses coming with a belay loop: http://www.bdel.com/gear/alpine_bod.php Don't forget there is a Bod, and an Alpne Bod.

[knotzen]

I own a BD Bod...

 

...it's a nut-masher.

 

Hm, it doesn't mash my nuts.

 

Oh wait, I don't have any...another good reason to be a girl.

[knotzen]

Of course, my gear sling is a boob masher. I hate that.

[murraysovereign]

Of course, my gear sling is a boob masher. I hate that.

 

Whoa!! Sounds like you may be "triaxially loading" your gear sling - it could potentially fail under the stress. Maybe you should put it around your neck so it hangs straight down in front, instead of across your shoulder?

[knotzen]

it could potentially fail under the stress.

 

Yeah, that's what I'm worried about. Oh wait, do you mean my boob, or the gear sling?

 

Oops, wandering into spray territory. I'll shut up now and go pack for climbing tomorrow. And rethink that triaxially loaded gear sling.

[Blake]

I just picked up the Camp xlh 130 harness. IT doesn't have a belay loop, but I now prefer it to the aline bod. For mountaineering and alpine rock, it rocks! I've taken it cragging a couple times, and it is equally as uncomfortable as my alpine bod, meaning not great, but not horrible. I've only fallen on toprope though, no lead falls with it yet. @ 4ounces, and the size of a baseball, it is a big weight/space savings in the pack.

[Tumblemark]

Err, here's a little detail that might have been overlooked in the paranoia about triaxial carabiner loading. The "load" will be limited by the peak force at which the belay rope slips through the belay device. That maximum force is about 2 kN, maybe as high as 3.5 kN for a Münter hitch belay. That's still half the cross-loaded spec for locking carabiners. In other words, Jason and Dru and anyone else who worries about this mode of carabiner failure, it is impossible to break a belay carabiner by applying a load through a belay device--even by a fall directly on the belay when the belayer is solidly tied off (well, you might come up with some convoluted scenario using a locked Gri-Gri or a biner over a hard edge, but that's OT) Any story to the contrary will have to explain how a sufficiently high force could be applied through a conventional belay device; finger trouble is a far, far more probable cause of failures.

 

The belay loop on a harness may help avoid triaxial loading, but that only makes for smoother and less clumsy belaying, not prevention of hypothetical biner failure.

 

So to Blake's question: what to do about a harness that has no belay loop? The optimum answers depend on whether you mean belaying a leader or belaying a second. If belaying the second, you should belay directly off the anchor (not through a redirect, not off your harness, any harness). There are many reasons to belay seconds directly off the anchor using a GiGi, B-52, Reverso, Matrix, Münter hitch, etc. The maximum force a second could deliberately put on a belay rope, without slack, is at most twice their weight; call it 2 kN.

 

If belaying the leader, belay off your harness. I'd recommend creating a "belay loop" on your Alpine Bod by cinching a very short runner around the normal tie-in point (waist belt and legs loop). This will accomplish the main purpose of a belay loop: keeping the HMS biner and any fall load more or less lined up and centered on the harness where it's supposed to be. It also keeps the belay device away from clothing, hair, tie-in loop etc; this setup also works well for rappelling (especially with a self-belay). Slightly extending the HMS biner with a runner may make the belay device a little more floppy, but addressing that is a matter of rope handling technique (you wouldn't want a sloppy belay anyhow).

 

Plenty of data (much more than just Leubben) show that side-loading a figure eight follow through (or whatever you want to call the loading that occurs to a tie-in loop made with a figure eight follow through if you clip a biner to it) can cause failure of the knot at body weight or even less. There is a lot of scatter in such data, but the message is clear: don't do it. (This is the main reason for not using a figure eight to join to rappel ropes.) I haven't seen convincing data saying that tucking the rope tail into the knot makes this worse, but that seems reasonable. I wouldn't bet that a backup knot fixes the problem either. Even if you use a Yosemite bowline tie-in knot, which is a better choice and doesn't have the side loading failure problem, it's probably still not a good idea to belay off your tie-in loop if other options are available.

 

Sorry for the long answer. The best more thorough exposition I've found of the sense and science behind all this is a new book called The Mountaineering Handbook (see Amazon; cheap at $13).

[catbirdseat]

I hadn't heard of this 2 kN figure before, but it seems completely reasonable. It makes total sense when you think about it. If belay biners could fail by cross loading, they would, but you never hear about. I think I've heard about maybe one instance.

[ketch]

I recall seeing a listing once I can't remember the source. It was a series of tests on popular belay devices and what force they slipped at in standard configuration. It showed an ATC at 2 Kn and varied on the way up to a GriGri at 6.5 Kn. Some of the alternate configs had quite a bit of force. I will try to track down that data unless someone has a link.

[Dru]

 

So since the maximum force is only 2 kN, no biner should ever break

[Cobra_Commander]

I can't believe this thing is still alive

 

it's dangerous out there yer all gonna die!

[catbirdseat]

 

So since the maximum force is only 2 kN, no biner should ever break

Dru, no need to obfuscate the issue. Biners can and do break, but it is far more likely the one on your last piece of pro.

[Tumblemark]

For an easy start on belay rope slip forces, see the Petzl web site. Or the "manual" that comes with some of their hardware. When you work through the physics it turns out that 2 kN is pretty smart, because it limits the max force on your last biner (that's the one you want not to fail) to a reasonable level--as catbirdseat is getting at. To repeat, Dru, belay biners NEVER break due to cross- or triaxial loading when using a conventional belay brake.

[Dru]

So how do you account for broken belay biners then? UFOs? Communist flouridation of preciuous bodily fluids? Mass hallucination?

[tomtom]

So how do you account for broken belay biners then?

Microcracks. Must have been dropped.