/ GriGri for multi-pitch trad

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Rich Tyler - on 27 Apr 2013
Hi Guys,

Just wanted to get a census of peoples views on using a grigri for multi-pitch trad routes over a standard style ATC or bug style belay device.

It is often cited that the main concern with using a grigri for trad is the lack of dynamic belaying which can ultimately shock the runners, whilst on a multi-pitch stance this can be hard to manage with any belay device so just wanted peoples thoughts on this.

Obviously the grigri can only be used on single ropes so i understand this is a factor in many peoples decision.

Richie
petegunn on 27 Apr 2013
In reply to Rich Tyler: Not very good if you need to bail, abseil.
Jamie B - on 27 Apr 2013
In reply to Rich Tyler:

I'd use something that is lighter and more versatile.
neilwiltshire on 27 Apr 2013
In reply to Rich Tyler:

I'd say there's a number of problems using a Grigri for trad.

- The more trad you do, the more you abseil. Grigri's aren't well suited to this
- The more trad you do, the more you will want to use a pair of half ropes to help eliminate rope drag. Grigri's cannot cope with this.
- The more multipitching you do, the more fed up you will get of belaying from above with the device on your waist (hard work), you will eventually buy an ATC Guide of Petzl Reverso anyway which is life changing when belaying from above!

I say make life easier for yourself from the start and buy an ATC Guide and learn how to use it in guide mode.

James S - on 27 Apr 2013
In reply to Rich Tyler: generally a bad idea i'd say, heavier and far less versatile than a standard device. in fact i cant see a single pro for taking a grigri rather than a standard device.
David Coley - on 27 Apr 2013
In reply to Rich Tyler:
Depends on the length of the route and if you plan to use a single. For 2 pitch uk trad, no point. For a 23 pitch route where the second will be half asleep by hour 18, a great idea.
LJC - on 28 Apr 2013
In reply to Rich Tyler: Grigris are more versatile than you give them credit for.

You can belay directly off an anchor (as in guide mode) and its much easier to release and lower if needed.

You can rappel easily and if you know some basic rope work you can set up a retrievable ab with only minimal extra faff and gear.

The dynamic belay is a bit of a ukc fallacious argument. On the ground you can give a softer sport style catch if appropriate. The idea that a belay plate is softer due to slippage isn't true on comparison to a person moving to soften a catch. Up on a stance, I really don't think I want my belayer letting rope slip through a plate to soften my fall, I want the rope totally locked off. I think that the vast majority of people climbing aren't on routes with such marginal gear as to require shock lessening tactics from their belayer. Just put some good gear in!

Having said all this, I think if you need to ask about a grigri on a multipitch, you should probably stick with what you know and improve your technique with basic gear before experimenting.

The downsides? Weight, and incompatibility with half ropes. The grigri is my default device as long as I don't want to be cutting the grams, or using halves. It's no surprise that a grigri is a mandatory piece of gear for big walls, aid or free
Robert Durran - on 28 Apr 2013
In reply to LJC:
>..... incompatibility with half ropes.

The most obvious problem! As a matter of interest, are Grigris used in America where no one seems to use or appreciate the advantages of double ropes?
AJM - on 28 Apr 2013
In reply to Robert Durran:

I climbed once or twice with a yank who used a grigri for almost everything. With proper dynamic belaying the increased impact force is probably taken away. Means you have to be happy falling further though I suppose but that didn't seem to bother him.

They're popular for belaying aid as well aren't they?
rocky57 - on 28 Apr 2013
In reply to AJM:
> (In reply to Robert Durran)
>
> I climbed once or twice with a yank who used a grigri for almost everything.

I've now got this mental picture of an american wearing a harness racked with about a dozen grigri's.
LJC - on 28 Apr 2013
In reply to Rich Tyler: To be honest, I imagine a grigri in a crack would be as strong as a hex to lob on...
highclimber - on 28 Apr 2013
In reply to Rich Tyler: Just get a petzl reverso or similar. more versatile, lighter and cheaper. Grigris are excellent but not really conducive to multipitch trad climbing.
redcal - on 28 Apr 2013
In reply to Rich Tyler: was very gri gri friendly in the states, but not really in trad multi pitch settings, still mostly used a guide plate. multi pitch bolted stuff we would occasionally trail a second rope to ab and climb on a singe rope which lent itself to belaying the 2nd with a gri gri. Ultimately a very useful single pitch tool, but limited in multi pitch scenarios..
Trevor Langhorne on 28 Apr 2013
In reply to LJC:

I am not sure where you have got your information from but you are presenting a restricted set of points and have not differentiated between what is fine for bringing up your second and what is fine for belaying your leader.

Petzl do not recommend a GriGri except on sports routes - reason: shock loading. In my view the manufacturer probably has a fair grip of the factors involved. Having said that I can see no reason why they can't be used to bring a second up (given the proviso that a single rope of appropriate diameter is used) as the forces are so low that the dynamic capabilities of a standard belay plate will not come into play.

> You can belay directly off an anchor (as in guide mode) and its much easier to release and lower if needed.
>
I presume you are talking about bringing up a second. If not I guess that you forgot to mention the caveat that for direct belaying you must have absolutely solid multi-directional anchors. If the anchor pops there is nothing the belayer can do but follow the anchor down the crag. Having your body in the system between anchcors and your climbing partner can add extra dynamic capability to the set up.

> Up on a stance, I really don't think I want my belayer letting rope slip through a plate to soften my fall, I want the rope totally locked off. I think that the vast majority of people climbing aren't on routes with such marginal gear as to require shock lessening tactics from their belayer. Just put some good gear in!
>
I presume that you are referring to the leader being belayed. Research done by BD (I think it was them, may have been in a belay device review in the American Magazine "Climbing") showed that all belay plates when held correctly for leader belaying only generate sufficient friction to hold a force up to somewhere between 2 and 3kN (depending on the slickness of the device). Any force above this value will automatically lead to rope slippage whether or not you or your belayer want it. Belay gloves can be handy. This rope slippage is what keeps the forces in the system down.Using a Grigri removes this energy dissipation option thus the forces experienced by the climbers, rope and gear can be much bigger.

You are correct that the vast majority of climbers aren't doing lots of marginally protected routes; howeverit is not always possible to place good gear wherever you want, people can miss really obvious placements, they can deliberately pass a runner to avoid getting pumped placing it (or to avoid filling up a useful hold) and even bomber runners can be dislodged by rope movement; all these factors can turn what should have been a short ride into something more exciting with a lot more energy to be dissipated hence peak forces rise - putting a GriGri in just helps increase these forces.

If you want to see just how easy it is to generate large forces in small falls have a look at the DMM video compating nylon and dyneeema slings.

You are quite right to suggest that the op should only be using techniques that they are confident and experienced with.





LJC - on 29 Apr 2013
In reply to Trevor Langhorne:
> (In reply to LJC)
>
> [...]
> I presume you are talking about bringing up a second. If not I guess that you forgot to mention the caveat that for direct belaying you must have absolutely solid multi-directional anchors.
>
Yes, of course I mean bringing up a second. Who would realistically try to belay a leader directly off an anchor whilst in guide mode (as mentioned)?

> [...]
> all belay plates when held correctly for leader belaying only generate sufficient friction to hold a force up to somewhere between 2 and 3kN (depending on the slickness of the device). Any force above this value will automatically lead to rope slippage whether or not you or your belayer want it. Belay gloves can be handy. This rope slippage is what keeps the forces in the system down.Using a Grigri removes this energy dissipation option thus the forces experienced by the climbers, rope and gear can be much bigger.
>
This is assuming a completely static belay. The movement of the belayer upwards during a fall is going to completely negate any extra force which may be caused by a grigri camming the rope tight in comparison to a plate catch - surely by an order of magnitude? I've caught loads of falls, indoors and outdoors, on both regular plates and grigris. I've never felt any rope slippage with a Reverso or ATC even on some fairly short nasty high ff falls (which of course is anecdotal), but I can only assume was due to my movement during the fall.


> You are correct that the vast majority of climbers aren't doing lots of marginally protected routes; howeverit is not always possible to place good gear wherever you want, people can miss really obvious placements, they can deliberately pass a runner to avoid getting pumped placing it (or to avoid filling up a useful hold) and even bomber runners can be dislodged by rope movement; all these factors can turn what should have been a short ride into something more exciting with a lot more energy to be dissipated hence peak forces rise - putting a GriGri in just helps increase these forces.
>
I don't see how any of these scenarios have relevance. Bad gear happens, and if it's so poor it drops out, a difference in belay plate wont help. I understand that a small range of placements may benefit from reduced peak loading which plate slippage may provide, but so will movement from your belayer, unless he is lashed down tight to the 3rd pitch belay? Yes, anchors should be omnidirectional, but the OP wasn't asking about this.

> If you want to see just how easy it is to generate large forces in small falls have a look at the DMM video compating nylon and dyneeema slings.
>
Very true. Don't climb above your cowstail, or attach to the anchor with your rope.

> You are quite right to suggest that the op should only be using techniques that they are confident and experienced with.
>
Amen. I'm only giving the other side of the story. I've been told off by a stranger for belaying single-pitch trad on a grigri (which isn't the situation the op was referring to), and it's just a flawed argument to say it's not appropriate. Look at some El Cap vids and see what they are all using.

I do however use a guide plate a lot of the time.

martinph78 on 29 Apr 2013
In reply to Rich Tyler: I can't add much to the above, except I tried one on single pitch routes and glad I hadn't taken it on a multi-pitch route. I have since sold it.

I found that if you are belaying close to the ground (i.e. sat on the edge of the crag) it wanted to turn over when weighted which made it very difficult to release. Even without it turning over, I found having it close to the rock/touching made it very awkward to try and use the release handle. Not sure I'd fancy using it in a guide mode where it would be hanging against the rock.Finally, I also found there was more chance of dropping it when attaching than with an ATC for example. Yeah, yeah, I know it's possible to drop anything, but I don't remove my bug from my carabiner completely when inserting the rope, you have to with the Gri-Gri.



Jonny2vests - on 29 Apr 2013
In reply to LJC:

I'd like to know how the belayer is supposed to move around to supply this dynamic belay halfway up a multi pitch trad route.
Jonny2vests - on 29 Apr 2013
In reply to Robert Durran:
> (In reply to LJC)
> >..... incompatibility with half ropes.
>
> The most obvious problem! As a matter of interest, are Grigris used in America where no one seems to use or appreciate the advantages of double ropes?

I've never seen anyone belaying trad with a Grigri in the States or Canada. Obviously they've all been led astray by UKC if LJC is to be believed.
LJC - on 29 Apr 2013
In reply to Rich Tyler: Climber goes down, belayer goes up? I thought that was obvious. I was mentioning it in a big wall context, not that all Americans regularly belay sketchy gear, multi pitch trad routes, with double ropes stuffed in one grigri.
jon on 29 Apr 2013
In reply to Martin1978:

> Not sure I'd fancy using it in a guide mode where it would be hanging against the rock

Grigris work just fine in 'guide' mode. I use mine often like this. Just orient it so the lever doesn't jam against the rock. What I DON'T like is using a single rope for trad. Yanks do it all the time... and carry dozens of slings to try to reduce drag and trail a second rope purely to rap on. Just plain daft.
Jonny2vests - on 29 Apr 2013
In reply to jon:
> (In reply to Martin1978)
>
> [...]
>
> What I DON'T like is using a single rope for trad. Yanks do it all the time... and carry dozens of slings to try to reduce drag and trail a second rope purely to rap on. Just plain daft.

Yeah, especially when 30m is generally considered a short pitch. It's bizarre.
Trevor Langhorne on 29 Apr 2013
In reply to LJC:
> (In reply to Trevor Langhorne)

A final couple of points before I pack my Grigri and head for Kalymnos.

> This is assuming a completely static belay. The movement of the belayer upwards during a fall is going to completely negate any extra force which may be caused by a grigri camming the rope tight in comparison to a plate catch - surely by an order of magnitude? I've caught loads of falls,....... but I can only assume was due to my movement during the fall.
>
Best not to assume or guess in circumstances which could have terminal consequences!

> I don't see how any of these scenarios have relevance. Bad gear happens, and if it's so poor it drops out, a difference in belay plate wont help. I understand that a small range of placements may benefit from reduced peak loading which plate slippage may provide, but so will movement from your belayer, unless he is lashed down tight to the 3rd pitch belay? Yes, anchors should be omnidirectional, but the OP wasn't asking about this.
>
Obviously i didn't express myself very well. If a fall ends up being longer than expected due to protection being missed or falling out then I think a dynamic belaying device becomes even more important to keep the shock loading on the belayer and gear as low as possible. Like you I have held many leader falls, from hip belaying with a hawser laid and kernmantel ropes, through using sticht plates, tubular "plates" like ATC and VC Pro)and, of course the Grigri (Marks 1 and 2). Personally I like my VC Pro.

> Amen. I'm only giving the other side of the story. I've been told off by a stranger for belaying single-pitch trad on a grigri (which isn't the situation the op was referring to), and it's just a flawed argument to say it's not appropriate. Look at some El Cap vids and see what they are all using.
>
Just because lots of people do it does not make it safe! Look at photo's of Livesey and the like from the late 70's. Once you have finished admiring their sartorial elegance you may notice that no quick draws were used, wires were clipped with two caraabiners forming like a mini chain. We all did it but that didn't stop one crab from twisting round and unclipping itself from the other crab with obvious consequences.

Enjoy your climbing.

SARS on 29 Apr 2013
In reply to LJC:

I'm with you. When I lived out in California I saw grigris being used quite a bit.

I think using a grigri for trad is fine. The dynanic belay argument is pretty weak - the best way to give a dynamic belay is to do a little jump if the leader falls. The extra 1 inch of give a standard plate gives isn't going to add up to much.

I might not use it so much for multi pitch though, just because of the weight issue.

As for single versus half ropes - well personally I much prefer using long slings and extending than using half ropes. Maybe I've spent to much time climbing with yanks, but when I came back to the UK and had to get used to half ropes again (because of climbing partners' insistence) it was tough. Half ropes are a big hassle for many reasons.
David Coley - on 29 Apr 2013
In reply to Trevor Langhorne:

In my mind it comes down to this:
1. a gri gri has the potential to increase forces.
2. a standard plate has the potential to be let go of when the second gets smashed into the rock, or because they are half asleep after 12 hours on the job, are cold and wet and it's got dark now you are on pitch twenty.

So, one might say, it all depends on the route and the climbers.

It is worth pointing out that it is rare to see someone climbing multi pitch aid with anything but a grigri-type device; and on aid the gear really can be shit and the falls massive.
Robert Durran - on 29 Apr 2013
In reply to SARS:
>
> As for single versus half ropes - well personally I much prefer using long slings and extending than using half ropes. Maybe I've spent to much time climbing with yanks, but when I came back to the UK and had to get used to half ropes again (because of climbing partners' insistence) it was tough. Half ropes are a big hassle for many reasons.

Care to give some examples?

I would pay good money to watch an American try to climb Right wall on a single rope.

Jonny2vests - on 29 Apr 2013
In reply to SARS:
> (In reply to LJC)
>

> I think using a grigri for trad is fine. The dynanic belay argument is pretty weak - the best way to give a dynamic belay is to do a little jump if the leader falls. The extra 1 inch of give a standard plate gives isn't going to add up to much.
>
> I might not use it so much for multi pitch though, just because of the weight issue.

Not only that, but I'm still waiting for someone to tell me how you leap into the air on a multipitch trad belay. Who constructs a trad belay with that in mind?
SARS on 29 Apr 2013
In reply to Jonny2vests:

Sure, but do you really think the slippage in a standard plate adds up to much?
Jonny2vests - on 29 Apr 2013
In reply to SARS:
> (In reply to Jonny2vests)
>
> Sure, but do you really think the slippage in a standard plate adds up to much?

I don't know is the answer, which is why I think guessing whether its safe isn't wise. Maybe someone has done some tests?
SARS on 29 Apr 2013
In reply to Robert Durran:

Well mainly I'm a lazy bastsrd and can't be arsed to carry, bring up and then coil two ropes quite frankly. And I just don't see the issue with extending. On multi pitch I simply find two ropes becomes tiresome.

I don't know Right Wall so can't comment. Done plenty of circuitous routes on singles though.

Jonny2vests - on 30 Apr 2013
In reply to SARS:
> (In reply to Robert Durran)
>
> Well mainly I'm a lazy bastsrd and can't be arsed to carry, bring up and then coil two ropes quite frankly. And I just don't see the issue with extending. On multi pitch I simply find two ropes becomes tiresome.
>
> I don't know Right Wall so can't comment. Done plenty of circuitous routes on singles though.

I might take a single on something I know well or trying to do fast because I agree, it is (slightly) less faff, and you tend to put less runners in anyway if its speedy territory. But if I'm on some big route for the first time, that I might bail on or think the second might struggle on or might need to wander unpredictably or might need to run pitches together, then give me doubles any day.
jkarran - on 30 Apr 2013
In reply to Rich Tyler:

If it's all you've got that you can use then use it. If it's not then it's probably not the best tool you have with you. To be honest, unless you have a very good reason for using it I'd save the weight and just take the krab it's on for an Italian hitch. That's coming from a GriGri fan.

jk
Neil Williams - on 30 Apr 2013
In reply to jkarran:

I know that was partly in jest, but just in case anyone does do that... because the krab a GriGri goes on is "metal on metal", if you're going to do that check it for damage first, if it's got any significant scrapes it could damage or unduly wear the rope.

Neil
HeMa on 30 Apr 2013
In reply to Jonny2vests:
> (In reply to SARS)
>> (In reply to LJC)
>> I think using a grigri for trad is fine. The dynanic belay argument is >> pretty weak - the best way to give a dynamic belay is to do a little
>> jump if the leader falls. The extra 1 inch of give a standard plate
>> gives isn't going to add up to much.
>>
>> I might not use it so much for multi pitch though, just because of the
>> weight issue.
>
> Not only that, but I'm still waiting for someone to tell me how you leap
> into the air on a multipitch trad belay. Who constructs a trad belay
> with that in mind?

I do, always build the anchor high, makes life a lot easier (when using guidemode, grigri or what ever to bring up the 2nd(s), or to move around the stand). When the powerpoint is above yer head, leader falls the belayer can go a little less than 1 m up without even touching the powerpoint. I think that helps to reduce the impact on marginal gear quite a bit more than 15cm of rope slippage through the tube-type belay device. NO?

And as someone already stated, a belay should ALWAYS be multidirectional if there's climbing above it (not really needed if you're at the top, but still a good idea).
jkarran - on 30 Apr 2013
In reply to Neil Williams:

It wasn't in jest. The Two metal parts are of comparable hardness and properly deburred, the GriGri doesn't do the krab any harm. I frequently use my GriGri krab for other things (it's generally the only screwgate I have with me), the only burrs on it are grit rash!

jk
Martin W on 30 Apr 2013
In reply to Jonny2vests:
> (In reply to SARS)
> > do you really think the slippage in a standard plate adds up to much?
>
> I don't know is the answer, which is why I think guessing whether its safe isn't wise. Maybe someone has done some tests?

As Trevor Langhorne already mentioned above, tests have been done on slippage in ATC-style belay devices. IIRC DMM reported their results on here back when they first introduced the Revolver krab. It's entirely possible that BD have done similar testing, they're thorough like that. One online reference is https://www.thebmc.co.uk/ae-microwire-failure:

Experimental measurements using popular belay devices have shown that the peak force in the rope running to the belayer can reach up to 2.5kN, reducing to less than 1.5kN with a thin rope and a slick belay device.

I don't know where the BMC got their figures from but you could always contact them and ask.

To my mind there seems to be a bit of a mismatch between the arguments that (a) it's possible to give a dynamic belay with a Grigri from a stance on a multi-pitch route, and (b) the Grigri is better if your belayer is likely to fall asleep/lose concentration.

UPDATE: The info from DMM re slippage/maximum force in a belay plate was posted here: http://www.ukclimbing.com/forums/t.php?t=83567#x1151112 (Simon Marsh was with DMM at the time he posted that, I don't know whether he still is).

UPDATE 2: Simon is still listed on DMM's web site, as responsible for overseas sales.
jkarran - on 30 Apr 2013
In reply to Martin W:

> To my mind there seems to be a bit of a mismatch between the arguments that (a) it's possible to give a dynamic belay with a Grigri from a stance on a multi-pitch route, and (b) the Grigri is better if your belayer is likely to fall asleep/lose concentration.

Where's the mismatch? They look like two quite different, non contradictory statements to me?

You can give a 'dynamic belay' from many belay stances (the majority I can recall) if you so desire.

A sleepy belayer with a GriGri is more likely to catch you than a sleepy belayer with something slick lke an ATC.

Combine the two statements and I'd still go for a sleepy-belayer hard catch over a sleepy-belayer drop every time!

jk
Neil Williams - on 30 Apr 2013
In reply to jkarran:

Useful to know, cheers. I always tended to keep a dedicated krab but maybe as you say I don't need to.

Neil
jkarran - on 30 Apr 2013
In reply to Neil Williams:

There's no harm in checking but that particular combo has never given me any cause for concern.

jk
Jonny2vests - on 30 Apr 2013
In reply to Martin W:

Thanks Martin, but I was talking about a test that compares impact forces on the top runner when using a Grigri vs a standard plate.
Jonny2vests - on 30 Apr 2013
In reply to HeMa:

Interesting that you build the anchor with a dynamic belay in mind. Surely a lot of the time, you simply don't get that choice?
Robert Durran - on 30 Apr 2013
In reply to Jonny2vests:
> (In reply to HeMa)
>
> Interesting that you build the anchor with a dynamic belay in mind. Surely a lot of the time, you simply don't get that choice?

I wonder how many people actually do construct a belay with an upward force in mind. Very few I suspect!

Ciro - on 30 Apr 2013
In reply to Rich Tyler:

To the OP, if you want a device that does it all, get an alpine up:


http://www.gocragging.com/Climbing_Technology_Alpine_Up_p/ct_alpine_up.htm

note that the manufacturers *don't* recommend assisted locking mode for hand placed pro though.

To those who think an inch can't make much difference, if you're always belaying from a standing stance, and ready to move with the catch it probably doesn't, but if you're sitting in a hanging belay, or caught off guard and don't give, assuming the slippage happens as the rope reaches the end of its elasticity - which seems a reasonable assumption given that'll be the point of peak load on the device - it could make a huge difference to the peak load on the top runner.

Obviously there's a tradeoff as others have mentioned if you are multi day bigwalling and your belayer might fall asleep, but i know which i prefer for a regular multipitch climb.
Robert Durran - on 30 Apr 2013
In reply to Ciro:
> (In reply to Rich Tyler)
>
> To the OP, if you want a device that does it all, get an alpine up:

http://www.gocragging.com/Climbing_Technology_Alpine_Up_p/ct_alpine_up.htm

If this is as good as the single rope Click-Up, then it will be an awesome bit of kit (especially for old farts such as myself to whom the operation of a grgri is a counterintuitive mystery!). However, the Click-Up certainly has very little "give" in the way it locks if that bothers people (obviously, as with Grigri, no problem for sport climbing - just very safe).
Jonny2vests - on 30 Apr 2013
In reply to Robert Durran:
> (In reply to Jonny2vests)
> [...]
>
> I wonder how many people actually do construct a belay with an upward force in mind. Very few I suspect!

Anchors that an take an upward pull? That's reasonably normal isn't it? I don't however routinely build into a trad belay the facility that lets me get pulled up as if I was belaying on the ground, which is often more than a metre.
HeMa on 30 Apr 2013
In reply to Jonny2vests:
> (In reply to HeMa)
>
> Interesting that you build the anchor with a dynamic belay in mind. Surely a lot of the time, you simply don't get that choice?

To be honest, dynamic belay isn't the point. Rather an added bonus. I build the powerpoints high up for easier use of guide mode, easier to move around the stand and generally more hassle free place.

Oddly enough, I really can't remember more than 2 or 3 occations where I couldn't do this. But then again, I do mainly climb on granite or gneiss. Which means the routes go up cracks and cracks make rather easy to build belays.
rgold - on 01 May 2013
In reply to Rich Tyler:

My take is that most of the time the difference between locking devices and tube-style devices is moot. The rope has to slip and run through the tube-style devices in order to realize their theoretical load-limiting advantages, and this doesn't seem to happen all that much, probably because the total amount of friction in a typical climbing system prevents loading the belayer at or beyond the slipping threshold. The net result is that most of the time Grigris and tube-style devices result in the same static belay, so use whatever you want.

I don't think the so-called "dynamic belaying" techniques used by sport climbers are relevant to multipitch trad climbing; there are way too many circumstances where the precisely-timed jump needed to obtain load reduction just isn't going to happen, and the CAI belaying tests indicate that simple lifting of the belayer has a minor effect on peak load---nothing like the "order of magnitude" suggested earlier.

There is, in principle, a way to get a bit of load reduction from slippage through a tube-style device without the rope running through the belayer's brake hand: this is what the CAI testers called the "inertial phase" of the belay, when the rope slipping through the plate pulls the belayer's hand up to the plate. (Rope only slips through the belayer's hand in the next phase, when the hand can't move anymore).

However, the inertial phase reduction, which is might be similar to what you might get from a screamer (and so depends on the actual length of the fall and not the fall factor), is often, at least from my observations, precluded because belayers tend to keep their brake hand very close to the belay plate.

So if Grigris and tubes effectively, in the field, have the same loading effects almost all the time, what about the relatively rare circumstances when a combination of fall severity and low systemic friction cause the rope to run through the belayer's hands? This certainly has a "safety valve" effect that isn't available from a Grigri, but it comes at the expense of a potential loss of control of the belay, or at least the burning of the belayer's hands, since in my experience only a minority of belayers use gloves. As ropes get thinner and thinner, the chances of loss of control and burning increase.

Put all this together and I think that most of the time it doesn't matter, but when it might matter you're still better off with some kind of locking device, especially if you aren't going to wear gloves for belaying.

Although Grigri's don't work on half ropes, we now have The Mammut Smart Alpine, the Climbing Technology Alpine Up, and the Edelrid Micro and Mega Juls, all of which provide (assisted) locking on half and twin ropes, and so the discussion is still relevant for these other systems even if the Grigri can't accommodate them. In fact, it is even more relevant because the thinner ropes used in double-rope systems are harder to hang on to.

SARS on 01 May 2013
In reply to rgold:

That is a very sensible post. Thanks.

And you've now also got me interested into looking at other locking devices for half ropes.
Jonny2vests - on 01 May 2013
In reply to SARS:
> (In reply to rgold)
>
> That is a very sensible post. Thanks.
>
> And you've now also got me interested into looking at other locking devices for half ropes.

this Alpine Up thingy sounds like the dog's.
jon on 01 May 2013
In reply to Jonny2vests:

This might be a good point to say that rgold is one of the few American advocates of double ropes.
Jonny2vests - on 01 May 2013
In reply to jon:

Yes, our paths have crossed.

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