DMM revolver + ATC: any experiences with this?

patto wrote: ...
Today I managed to catch a fall on a grigri without even the grigri engaging.....  AKA I gripped with my brake hand and my feed hand and it was the feed hand that seem to stop the fall!  Light climber, short fall..  Still it did surprise me a little.   But short fall and a bunch or quickdraws to add friction probably was a big part of it.
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A well known failure mode of the gri-gri: When the initial acceleration of the rope through the device is small (light leader, dainty plop, friction in intermediate pieces), then the assist-braking of the device does not activate ( petzl.com/US/en/Sport/Belay… "In fact, you may notice that if you slide your rope slowly through the device (especially for small diameter rope), it does not necessarily lock, and the rope slides freely through the device."). Therefore, keep that brake hand on the rope; let your belayer know that you're falling, even if it is a dainty fall...

In regard to the original OP question: I don't have data. That said, theory suggests that the reduction of friction on the carabiner surely reduces the braking ability of the system and decreases the range of falls that the belayer is likely to successfully hold. Philosophically, the purpose of the belay system is not to optimize rope to slip through the device for the convenience of the belayer; adding a revolver carabiner to the belay system seems like spraying a car's brake pads with WD-40 before going for a drive so that the car doesn't jerk to a stop when you slam on the brakes...

so basically it works because the revolver doesn't really function well as designed (which is pretty similar with other uses of the revolver).  duly noted....

patto wrote: An interesting side note....  As I'm sure you are aware the number of really hard catches is pretty damn low.  Two quick examples:

Today I managed to catch a fall on a grigri without even the grigri engaging.....  AKA I gripped with my brake hand and my feed hand and it was the feed hand that seem to stop the fall!  Light climber, short fall..  Still it did surprise me a little.   But short fall and a bunch or quickdraws to add friction probably was a big part of it.

A month or so ago I had a partner take a fall with only one piece between him and the deck and he was a decent stance above it.  I twinged my tricep catching that one.  Me yarding in half an armful of slack before it came tight might not have helped my tricep.   Minimal/no rope slippage on the catch but it was a hard catch, pretty close to FF1.

Yeah, you should get out of that terrible habit. It's a recipe for burned hands and dropped climbers. There's no reason for your guide hand to be above the belay device on the climbers strand for anything other than pulling in/paying out slack. When catching a fall, holding a hanging climber, or just not currently manipulating the slack, the best place for the guide hand to be is below the brake hand also holding the brake strand. The second best is maybe in your pocket. If you get in the habit of always bringing your guide hand back to the brake strand, that will be your default position and the muscle memory will serve you well when your climber takes a fall. Glad there was enough friction that you were able to arrest the fall, and without getting burned. Hope you're aware that could've turned out much worse. 

Em Cos wrote: 

Yeah, you should get out of that terrible habit. 

Which terrible habit is this?  Having my hand exactly where it needs to be to feed out slack?  Or to pull in slack.  I'll keep my guide hand where it is thanks.

Em Cos wrote:There's no reason for your guide hand to be above the belay device on the climbers strand for anything other than pulling in/paying out slack.

Aka your job as a belayer.  And sometimes this is even your job MID fall for falls close to the deck or on slab.

Em Cos wrote: If you get in the habit of always bringing your guide hand back to the brake strand, that will be your default position and the muscle memory will serve you well when your climber takes a fall. 

No.  That is certainly not my default position in belaying it will hamper good belaying in all sorts of situations.  In other situations I'll readily have two hands on the brake rope but it is hardly my default position.  My climber wants to climb.

Em Cos wrote:Glad there was enough friction that you were able to arrest the fall, and without getting burned. 

What makes you think I would have been burned?  My brake hand and gri-gri would have prevented rope movement.  

(Oh and yes I know of the stories of grigris and burnt guide hands.  But to get that you need to have rope being fed through the gri-gri.  How do you suppose that would occur in the braked position?)

Em Cos wrote:Hope you're aware that could've turned out much worse. 

You mean like the half dozen other falls that day which were slightly firmer and cause the grigri to lock up?  Hmmm, hardly much worse.

Of course if by all this your mere argument is that the guide hand gripping the rope during a fall is not helpful then I'd agree.  But if you can make a clear case why it REDUCES braking I'd like to hear it.

patto wrote:  But if you can make a clear case why it REDUCES braking I'd like to hear it.

The grigri uses tension to move the cam to stop the rope which arrests the fall. By having your hand above the grigri and taking some of the force of the fall, it reduces the tension in the rope. This lowered tension might not cam the grigri, making arresting the fall up to your hands, not the device.

patto wrote:
(Oh and yes I know of the stories of grigris and burnt guide hands.  But to get that you need to have rope being fed through the gri-gri.  How do you suppose that would occur in the braked position?)

If there is a loop of slack (or any slack for that matter) between your guide hand and the grigri then rope could burn your hand without sliding through the grigri.  That is how I suppose it would occur with the other hand in the braked position 

patto wrote: Which terrible habit is this?  Having my hand exactly where it needs to be to feed out slack?  Or to pull in slack.  I'll keep my guide hand where it is thanks.

Aka your job as a belayer.  And sometimes this is even your job MID fall for falls close to the deck or on slab.

No.  That is certainly not my default position in belaying it will hamper good belaying in all sorts of situations.  In other situations I'll readily have two hands on the brake rope but it is hardly my default position.  My climber wants to climb.

What makes you think I would have been burned?  My brake hand and gri-gri would have prevented rope movement.  

(Oh and yes I know of the stories of grigris and burnt guide hands.  But to get that you need to have rope being fed through the gri-gri.  How do you suppose that would occur in the braked position?)

You mean like the half dozen other falls that day which were slightly firmer and cause the grigri to lock up?  Hmmm, hardly much worse.

Of course if by all this your mere argument is that the guide hand gripping the rope during a fall is not helpful then I'd agree.  But if you can make a clear case why it REDUCES braking I'd like to hear it.

1. The one I bolded. "I gripped with my brake hand and my feed hand ". No, not having your hand where it needs to be to feed out or pull in slack, but gripping with your guide hand above the device to catch a fall. 

2. Your job as a belayer is to belay properly, including understanding how your belay device works and it's potential failure modes. There is, again, nothing wrong with pulling in slack during a fall - but you should not be gripping to catch a fall (intentionally or not) anywhere but on the brake strand below the device.

3. Yes, it would hamper good belaying in all sorts of situations. That's why it's not where your hand is always, just the default position. That means, it's a good place for your hand to be when you don't have a reason for your hand to be doing anything else at that moment. Those "all sorts of situations" where your guide hand is needed to belay well, are a good reason for it to not be in a default position. When the climber is falling, gripping the climber's strand hard is worse than useless, it could cause a bad accident. If you have this habit, it's not a bad idea to get a different default position into your muscle memory to prevent those types of accidents.

4. You know the stories of grigris and burned hands, but perhaps you don't fully understand them?

5. No, when I say it could've been much worse I am, of course, not referring to successfully caught falls. I'm referring to possibly a badly burned hand for you and possibly a ground fall for your climber, in the worst case scenario.

6. My argument is that the guide hand gripping the rope during a fall is not helpful, and potentially very dangerous. This is a well-known failure mode for the grigri and has resulted in dropped climbers. Zach Tom above references why. The fact that your hand is at best useless where you like to have it and could be useful on the brake strand should be enough to consider changing the habit, but your hand is at best useless and at worst the cause of a ground fall for your climber.

Apparently, you were not aware that it could have been much worse, so I'm glad I mentioned it and I hope this has helped raise your awareness. Happy belaying!

sourisse wrote:
So I'm curious if anyone here has experience actually catching lead falls with this setup, and what their thoughts are.

I think it's weird. If I saw that on my belayer, I'd either hand over a "real" 'biner to him, or go find a real belayer. I see no reason to reduce the capability of the system.

Sounds like they have expensive gear I would try to trick them into buying you dinner they must have some money

Em Cos wrote:

1......so... much.... conjecture.......

1. i dont agree with this at all. if you have a firm grip on the brake hand, when the climber falls and jerks the rope in the upper hand it will still create the tension difference across the cam to engage it.  i have belayed with a grigi for probably 25 years, and between gym climbing and outdoor climbing i have caught literally 1000's of falls while gripping the upper strand.  if you watch a lot of climbing videos you will see folks catching falls all day long with a hand on the upper rope. 

just think about it for a second, when you do a quick little grigri check and jerk on the climber strand, you have your hand on the..... wait for it.... climber strand! and it works. wow, magic!

now, if you are only gripping the top strand and not the brake strand, then i agree that you can definitely run into problems.  the brake hand is key for creating the tension difference across the cam.

having a hand on the upper strand puts you in more of a natural balanced stance to react during a fall. having both hands on the brake strand, particularly when the pile of rope is on your side, puts you in a shitty awkward, twisted position.  ugghhh.

gripping the climber strand gets listed as the cause of a lot of climbers fetting dropped, but i bet a dollar to a donut that the real root cause of these is not gripping the brake strand sufficiently.

slim wrote:

1. i dont agree with this at all. if you have a firm grip on the brake hand, when the climber falls and jerks the rope in the upper hand it will still create the tension difference across the cam to engage it.  i have belayed with a grigi for probably 25 years, and between gym climbing and outdoor climbing i have caught literally 1000's of falls while gripping the upper strand.  if you watch a lot of climbing videos you will see folks catching falls all day long with a hand on the upper rope. 

just think about it for a second, when you do a quick little grigri check and jerk on the climber strand, you have your hand on the..... wait for it.... climber strand! and it works. wow, magic!

now, if you are only gripping the top strand and not the brake strand, then i agree that you can definitely run into problems.  the brake hand is key for creating the tension difference across the cam.

having a hand on the upper strand puts you in more of a natural balanced stance to react during a fall. having both hands on the brake strand, particularly when the pile of rope is on your side, puts you in a shitty awkward, twisted position.  ugghhh.

gripping the climber strand gets listed as the cause of a lot of climbers fetting dropped, but i bet a dollar to a donut that the real root cause of these is not gripping the brake strand sufficiently.

It's actually both things. A gripped hand on the top keeps the grigri from engaging. Often enough, when a top hand gets rope burned the bottom hand reflexively drops the brake strand and grabs to try to help the burnt hand. It's a rare failure, sure, for the reason you said, but it happens. The key is to stop grabbing the top strand at all when catching a fall. I try to pull that hand way and focus on the bottom strand. 

slim wrote:

1. i dont agree with this at all. if you have a firm grip on the brake hand, when the climber falls and jerks the rope in the upper hand it will still create the tension difference across the cam to engage it.  i have belayed with a grigi for probably 25 years, and between gym climbing and outdoor climbing i have caught literally 1000's of falls while gripping the upper strand.  if you watch a lot of climbing videos you will see folks catching falls all day long with a hand on the upper rope. 

just think about it for a second, when you do a quick little grigri check and jerk on the climber strand, you have your hand on the..... wait for it.... climber strand! and it works. wow, magic!

now, if you are only gripping the top strand and not the brake strand, then i agree that you can definitely run into problems.  the brake hand is key for creating the tension difference across the cam.

having a hand on the upper strand puts you in more of a natural balanced stance to react during a fall. having both hands on the brake strand, particularly when the pile of rope is on your side, puts you in a shitty awkward, twisted position.  ugghhh.

gripping the climber strand gets listed as the cause of a lot of climbers fetting dropped, but i bet a dollar to a donut that the real root cause of these is not gripping the brake strand sufficiently.

Hey, either quote me or don't. 

Patto said that he/she was gripping the climber's strand such that it was his/her hand that stopped the fall, not the grigri. That's a potential problem, for reasons already stated. If you can keep your guide hand up there and still have it be a guide hand and not gripping during a catch, I guess that's fine - since it adds nothing to the effectiveness of the belay and is benign/useless at best, I really can't see the argument for it. But in Patto's case, the guide hand stopped the fall, not the grigri. I stand by that being a terrible habit, that will turn out ok until the day it doesn't. 

slim wrote:

1. i dont agree with this at all. if you have a firm grip on the brake hand, when the climber falls and jerks the rope in the upper hand it will still create the tension difference across the cam to engage it.  i have belayed with a grigi for probably 25 years, and between gym climbing and outdoor climbing i have caught literally 1000's of falls while gripping the upper strand.  if you watch a lot of climbing videos you will see folks catching falls all day long with a hand on the upper rope. 

just think about it for a second, when you do a quick little grigri check and jerk on the climber strand, you have your hand on the..... wait for it.... climber strand! and it works. wow, magic!

now, if you are only gripping the top strand and not the brake strand, then i agree that you can definitely run into problems.  the brake hand is key for creating the tension difference across the cam.

having a hand on the upper strand puts you in more of a natural balanced stance to react during a fall. having both hands on the brake strand, particularly when the pile of rope is on your side, puts you in a shitty awkward, twisted position.  ugghhh.

gripping the climber strand gets listed as the cause of a lot of climbers fetting dropped, but i bet a dollar to a donut that the real root cause of these is not gripping the brake strand sufficiently.

Exactly.

Em Cos wrote:
I stand by that being a terrible habit, that will turn out ok until the day it doesn't.

You can stand by that all you want.  But you logic does not follow on why it is so terrible.  If the brake strand is locked off and being gripped then all that will happen to the other hand is it moves slightly with the rope.  No rope burn, no disaster.

Going back to to gripping the non brake side.  It certainly isn't needed and I won't encourage it.  However there are many good reasons why your feed hand might be on the feed side during a surprise fall.  It is also VERY well documented that the reaction to grip with both hands is quite hard to repress.  (which has resulted in prussic above the device failures.)  Also like slim said once your hand is there it offers stability during the catch.

All that said I prefer to have two hands on the brake rope during a catch if it is practical.  But for many reasons that is not always practical.

Señor Arroz wrote:
It's actually both things. A gripped hand on the top keeps the grigri from engaging. Often enough, when a top hand gets rope burned

Hang on.  How does the top hand get burnt?  Your top hand has at least a foot of movement to it, by which stage the belay device would have become tight.  I've NEVER had movement through my feed hand.

Señor Arroz wrote:
the bottom hand reflexively drops the brake strand and grabs to try to help the burnt hand.

Um now you are just making stuff up.  My bottom hand isn't going to reflexively drop the brake stand.  The brake strand is my partners life and my life if I'm rappelling. It is ingrained knowledge.  Anybody who has reflexes to let go of their brake hand during a fall is not somebody I want belaying me.