Using ATC guide at a belay at the end of a traverse

I've been told that using the ATC in guide mode at a belay at the end of a traverse is not a good idea because it may fail to autolock. Thus, I've always belayed off my harness at the end of a traverse. However, I have played around with the ATC in guide mode and it seems like the autolock still engages even if the rope is coming in horizontal. Of course, when I've played around with this, the ATC was free to rotate about the carabiner that attaches the ATC to the anchor. I suppose there could be situations where that wouldn't happen.

Anyway, I'd like to know more about why this use of ATC in guide mode is not advised. I haven't been able to come across anything that discusses this in detail. Does anyone know where I can read more about this? Or could anyone provide an explanation for how autolock fails when guide mode is used at the end of a traverse?

Thanks!

The issue you're talking about comes into play if you are belaying two seconds and they are approaching from different angles. Say one falls near the end of the traverse, and is hanging below the belay now. The device is oriented down. The other second is before the traverse and still has gear above him. He falls, but the orientation of the device will not let it autolock.

Yes what Larry said. And...

Even with one follower you must be certain that the device can move freely and and orientate itself in the direction of pull which is towards the last piece of protection. This can be done easily by keeping all the slack out of the system so the device is already orientated properly. This should never ever be a hands-free situation. One hand on the brake!! I have witnessed this type of failure which led to a 30 foot ground fall and some badly sprained ankle's. Luckily it didn't end up worse.

Guide Mode.

For use by "Guides Only."

None of this is an issue if you are properly employing your brake hand and braking force.

The autoblocking feature of "guide mode" belaying is to provide assistance, not dismiss you from your responsibilities as a belayer.

I think it's highly situational.

Thin Air Traverse, Cathedral Ledge:
I noticed that the device would not engage in autoblock. Note that the two bolt anchor, and how I set it up, the anchor itself is kind of oriented for a downward force (not sideways). Also my last piece of pro may have been higher than the anchor. <<< This might be the key, I can't remember.

Anchor after Thin Air Traverse
Not the best picture, I believe this is after the last piece of pro has been removed. Also its quite obvious the 2nd is going for a ride before/ if the autoblock were to engage.

Updraft Traverse to Rap Tree, Gunks
After finishing P1 of Updraft, I slung the tree in the plumb-line with an 8' dyneema then traversed 40' right. Also probably rose in height 4-6'. (The dyneema extension brought the redirect lower than the final anchor) I noticed that the autoblock was rising up and aligning perfectly with the redirect, autoblock was working fine. To note, I am sure the autoblock would not have engaged after the redirect (last piece) was removed. And also, a cordalette on a slung tree meant the final anchor was setup oriented towards the traverse. This may have something to do with it.

Conclusion: Be aware

Tom, in the photo, you are pulling down on the brake. You should be pulling towards the last piece or towards the climber if the last piece has been removed keeping climber strand and brake strand parallel. The way you are pulling will reduce the devices ability to lock.

The device doesn't know or care which direction is up or down. It just sees forces.

The key, as others have said, is that the device is free to orient in the direction of force from the falling or hanging climber. As long as that's true, it will lock.

The whole issue with two climbers is that a pull in one direction from one climber/rope may break this rule and prevent the device from orienting properly for a pull in a different direction with the other climber/rope.

It's much more useful to understand principles than to memorize rules.

If belaying two seconds, make sure you redirect both ropes to orient the pull on the ATC Guide from the same direction, generally by clipping both ropes into the same piece.
The problem rises if your last piece before the anchor is far and a fall is possible, that would cause both ropes to enter the device at different angles...

This issue can also occur with sideways loading with one rope and follower. New skinny, slick ropes (somewhere around 9.2mm and smaller) can invert in the belay device and circumvent the auto-locking effect. This does not tend to be a major problem on the ATC-Guide but is a known issue on other plaquettes (notably the Kong GiGi and the Eldelrid MegaJul). This inversion occurs easiest with sideways loading, but on the other devices mentioned could occur with sufficient load and a sufficiently skinny rope even with a "straight down" load.

As noted by others, one solution is to maintain a brake hand (generally a good idea regardless). Another is to ensure the the device orients to the load (on a traverse this can make a sliding-x with limiter knots a good idea for the anchor rigging). Another would be to simply belay with a different device (GriGri and munter hitch both come to mind). You could also employ an auto-locking munter or possibly a stuflesser if you still wanted that added "hands free" security. I haven't tried it on an ATC-guide, so not sure how fiddly it would be on that device, but you could also give each climber their own braking carabiner if you're worried about one climber falling and circumventing the other's belay.

powhound84 wrote: Interesting take. Care to explain?

POWhound84..... The first time sombody used that set up on ME, I fell off and was about 15 feet below a roof..... Mr Wana Be Guide, mumbled something about "can you take your weight off?"

Me: "no way, just lower me to the deck"

Then I went for a ride, to the DECK... 20 feet sort of controlled....

The Next Time somebody had me on one of those, and he was a "guide" with certs, (but I wasn't paying a dime) I fall off and pendo 20 feet right, again out over nothing (guide training skips the "protect your second" now, I guess) So I'm in the air and ask to be lowered so I can start over.....

Mr. Jr Guide says: "uhnn.. can you take some weight off???"

Me: "no way, Just lower me to the ground"

Then I went for a ride, ALMOST to the Deck.... stopped about 4 feet up....

So you see, one needs to be a "GUIDE" to know how to use one of those deals correctly.

Guy Keesee wrote: POWhound84..... The first time sombody used that set up on ME, I fell off and was about 15 feet below a roof..... Mr Wana Be Guide, mumbled something about "can you take your weight off?" Me: "no way, just lower me to the deck" Then I went for a ride, to the DECK... 20 feet sort of controlled.... The Next Time somebody had me on one of those, and he was a "guide" with certs, (but I wasn't paying a dime) I fall off and pendo 20 feet right, again out over nothing (guide training skips the "protect your second" now, I guess) So I'm in the air and ask to be lowered so I can start over..... Mr. Jr Guide says: "uhnn.. can you take some weight off???" Me: "no way, Just lower me to the ground" Then I went for a ride, ALMOST to the Deck.... stopped about 4 feet up.... So you see, one needs to be a "GUIDE" to know how to use one of those deals correctly.

Lowering in guide mode is about the only time it's nice to be 245 lbs and climbing.

Guy Keesee wrote: The Next Time somebody had me on one of those, and he was a "guide" with certs, (but I wasn't paying a dime) I fall off and pendo 20 feet right, again out over nothing (guide training skips the "protect your second" now, I guess) So I'm in the air and ask to be lowered so I can start over..... Mr. Jr Guide says: "uhnn.. can you take some weight off???" Me: "no way, Just lower me to the ground" Then I went for a ride, ALMOST to the Deck.... stopped about 4 feet up.... So you see, one needs to be a "GUIDE" to know how to use one of those deals correctly.

To be fair, it depends on what those certs are. If a Single Pitch Instructor, the GriGri is the tool to use as the plaquette is not within the scope of the cert. This is not to say that any user employing a plaquette is absolved from knowing how to actually use one, but it shouldn't necessarily be linked to a cert. This is a chronic issue that I can never seem to address fast enough: climbers using a plaquette without the knowledge and skills necessary to effect a lower safely.