UKC

Since I arrived in Canada (8 months ago), I've had a steady stream of mates, randoms and guides come up to me and telling me 'I'm gonna die' if I belay from the rope loop; it is completely taboo in N America.

I have read all the threads, the UKC article, BMC booklets, yadda yadda yadda, all good stuff, in search of a good argument against the crux of theirs:

If the rope loop were to be loaded in such a way that the two strands out of the fig 8 were opposing, what's to stop it inverting? You might say (as Dan Middleton - BMC Tech Officer did) that this configuration is almost impossible to obtain when belaying, but if it did happen (surely it must have), why is nobody dead yet? Maybe a Jim Titt or an Rgold (yes, I've read those threads too) out there could provide a bombproof rebuttal.

In reply to jonny2vests:

If you've tied a stopper knot in the dead end, then it shouldn't go anywhere.

Belaying from the rope loop does mean you have an escapable system - you could, if you had to, attach something else to the belay krab that has it's own anchor and then untie the rope loop.

In reply to LastBoyScout:
>

Still pretty easy to escape when it's on the belay loop.

In reply to LastBoyScout:

Yeah, but I don't think that going to wash as 'bombproof'. Stopper knots come undone, we can't go around seriously relying on them.


How do you transfer the weight onto the new anchor?

In reply to jonny2vests: What about if you were tied in with a bowline instead if figure of 8?

In reply to woolsack:

I only use them for single pitch sport, harnessed wisdom seems to think it is a bad idea to belay from them. Unless it was a re-threaded bowline.

In reply to jonny2vests:
Ha! You´re in the country that elected Pierre Trudeau, they wouldn´t recognise a logical argument if it punched them in the face.

In reply to jimtitt:

Yeah, what do I tell these people Jim? Its not completely clear to me why, if the loop got ring loaded, it's not a problem..

In reply to jonny2vests:

Sounds to me like you fell in with a bunch of know-it-all busybodies. I've been belaying off my rope loop for a good twenty years now, all that time in North America, and no one yet has confronted me with predictions of imminent doom. However, compared to the UK and Europe, North America is a wasteland when it comes to testing, which means that we are all free to advance our pet theories unfettered by any actual facts, a phenomenon that has recently become a notable feature of our political discourse as well.

As a proud North American, here are my fact-free perspectives:

Tie a barrel knot (double overhand) as a stopper knot, it does not come undone, end of argument. If you are using half ropes or twins, clip into both rope loops, the chance of rolling them both open is zero.

That said, it is in any case nearly impossible to obtain the ring-loaded configuration if you are also tied to an anchor. (If you aren't tied to an anchor but are tied to the rope, there is no advantage to the rope-loop belay and in that case you might as well use the belay loop.) So now you are multiplying two miniscule probabilities, one that you can actually manage to truly ring-load the knot, and the other that a barrel knot stopper will come undone.

On top of that comes the question of whether an impact load of very brief duration can actually roll a figure-eight. All the tests I've seen were slow-pull tests appropriate to rappelling but not necessarily to belay loads. The slow-pull tests needed time to successively roll the knot until it rolled off the end, time that just isn't there when catching a fall.

If you are really paranoid or feel the need to keep the busybodies at bay, there is, for single ropes, the rethreaded bowline, which doesn't roll and which is a better tie-in knot than the figure-eight anyway.

It may be that "yer gonna die," but it is something other than a rolling figure eight loaded by a rope-loop belay that will get you.

As for ordinary or double bowlines, no climber should tie in with those knots without finishing them with some kind of stopper knot. Given that such a finishing knot is in place, bowlines can be ring-loaded. An un-backed-up bowline, which shouldn't even be viewed as a completed knot by climbers, will blow apart rather easily if ring-loaded. But such a knot should never be found on a climber's harness anyway.

In reply to rgold:

Show me.

In reply to Removed User:

Show you what? That a plain unadorned bowline is weak under ring loading? The DAV did a bunch of tests five, maybe more years ago and reached that conclusion. You can get such a bowline to untie when ring-loaded under body weight with some bouncing. I'm not going to show you but you can try it for yourself. By the way, at the time, those DAV tests found no analogous problem with the figure-eight.

I have read but never seen unequivocally confirmed that the so-called Dutch Navy bowline or left-handed bowline is somewhat more resistant to ring-load failure than the classically tied bowline. But using either variant without a stopper knot as a climbing tie-in is an invitation to disaster, with the probability of the knot loosening and perhaps coming completely undone increasing the longer the knot is on the harness.

The point is that J2V's Canadian busybodies might have a point if he was belaying off the rope loop formed by an un-backed-up bowline, but no one should be tying in that way to begin with.

In reply to jonny2vests:


This topic recently had a good going over at http://www.ukclimbing.com/forums/t.php?t=511621

What if, on a multi-pitch climb, you're belaying a leader who takes a fall big enough to lift you off the belay? You'd then unweight the anchors, leaving the rope loop ring loaded.

In reply to jonny2vests:
For me, the main reason not to belay off the the rope loop is that I might untie with the plate still on the loop, and therefore drop it down the cliff.

In reply to graham F:

The catch has to happen before the anchor strand is loaded, so it depends how you have rigged the belay and how far you are lifted relative to the anchor. Having caught some leader falls in exactly this situation, what has happened with me is that sometimes the knot is ring-loaded and sometimes the loop is lifted through the harness until the knot jams at the bottom end, so that ring-loading doesn't happen. (In my case, I'm using half ropes, so have two rope loops clipped, each tied with a double bowline with Yosemite finish and barrel knot backup. One of these falls, by the way, was near factor-2.)

The Moyers slow-pull tests using a well-dressed and tensioned flat figure-eight to join two dynamic ropes had the knot capsizing once at a very low load---in the range of 590-750 lbf, but after that holding until the rope broke at the knot. In other words, even without a backup, a well-dressed and tensioned figure eight with, say, one-foot tail is not not going to roll off the end of the rope. Moreover, because in the belay situation a loop is loaded, the load is divided between both strands and the knot sees roughly half the load, suggesting that analogous capsizing in the belay situation could require 1200--1500 lbf to produce the effects Moyers observed.

But of course the main point is that you use a backup knot on your figure-eight knot or use a rethreaded bowline if you are going to belay off the rope loop with a single rope, which ends the whole discussion about the figure-eight knot capsizing.

In reply to jonny2vests:
I am finding it hard to understand what most of you are on about, i always belay from the rope loop as this is what i was taught, except down at the climbing wall where i use the abseil loop, could someone explain to me like you are explaining to a complete idiot? When clipping a sling on an anchor i usually clip it straight into my rope loop at the top and then belay off the bottom end, is this wrong? If so why? What is ring loading?

Any simple explanations will be received with thanks.

In reply to rgold:

I don't disbelieve you. I just need to understand how it happens.

In reply to rgold:

Many thanks for your input as always.

In reply to abcdefg:

Thanks, I'll have a look at that.

In reply to Wesley Orvis:

Read the other thread linked to above.

In reply to Removed User:

Perhaps this will help? It is referenced in one of the other threads. vimeo.com/40767916

In reply to rgold:

Thanks. That's exactly what I was looking for.