belay plates on cave rope

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belay plates on cave rope

Postby ek » Mar 28, 2008 11:38 am

Are belay plates/Sticht plates, such as the Black Diamond ATC and the Petzl Reverso safe to use for belaying (single person loads) on (possibly wet and/or muddy) cave rope?

How about the auto-braking functionality for belaying from above that some of the newer devices, like the Reverso and the ATC Guide, have? Is that safe for use for belaying single-person loads on cave rope in cave conditions?

Finally, how about the Petzl Grigri?
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Re: belay plates on cave rope

Postby paul » Mar 29, 2008 2:10 pm

ek wrote:Are belay plates/Sticht plates, such as the Black Diamond ATC and the Petzl Reverso safe to use for belaying (single person loads) on (possibly wet and/or muddy) cave rope?

How about the auto-braking functionality for belaying from above that some of the newer devices, like the Reverso and the ATC Guide, have? Is that safe for use for belaying single-person loads on cave rope in cave conditions?

Finally, how about the Petzl Grigri?


Sticht plates and similar designs depend entirely on being able to pull the rope at 180 degrees to the direction of the rope being belayed so need to be in front of the belayer and there must be enough room to bring the controlling hand back in order to bring the rope 180 degrees away from the belayed rope.

The Gri-Gri is usable as a belay device for caving ropes (used by my local Cave Rescue organisation) however, care must be taken to always hold the controlling rope until safely locked-off as it may not autolock on a sudden load and also it releases suddenly when depressing the handle after autolocking. Care must be taken to prevent the autolocking being released unintentionally by allowing the device to press against any surface.
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Re: belay plates on cave rope

Postby ek » Mar 29, 2008 3:02 pm

paul wrote:Sticht plates and similar designs depend entirely on being able to pull the rope at 180 degrees to the direction of the rope being belayed so need to be in front of the belayer and there must be enough room to bring the controlling hand back in order to bring the rope 180 degrees away from the belayed rope.

That doesn't really address the question of how they perform with static or semi-static rope, with thick sheaths, in the presence of water and mud.

In many sport caving situations, the conditions specified above can be met.

In addition, devices like the Petzl Reverso and Black Diamond ATC Guide have an auto-braking mode for belaying and upward-moving climber from above. I am particularly interested in how well this works on stiff, wet, muddy ropes.
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Re: belay plates on cave rope

Postby chrismc » Mar 29, 2008 3:34 pm

I know from experience that if you rappel a nuisance drop on wet, muddy, hanging-in-a-waterfall using a Munter hitch, be prepared to eat a lot of mud. The friction does a nice job of cleaning the crud off the rope and depositing it on your face. I'd expect a similar experience using a Sticht plate. I now carry an 8 on me if I know the cave has many short (<50ft) drops, as it is much quicker than a rack on rappels that are more like "controlled jumps down".

To actually answer your post.. I have tried an ATC (genuine Black Diamond, the most ornery of them) on a caving rope, and couldn't even stuff the rope into it. A wider-mouth ATC-device may be usable (Pyramid, Piranha, etc...), but I personally wouldn't bother. A standard aluminum 8 is much better for this usage, and the bends are mild enough to work with well-used caving rope.
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Re: belay plates on cave rope

Postby ek » Mar 29, 2008 4:53 pm

But I'm talking about for belaying. I am interested in whether or not an ATC provides adequate braking friction on cave rope with cave conditions.

It's pretty undisputed that an ATC is a poor choice of caving descender. After all, it has very little mass, which means that it gets hot quickly, and it wears through rapidly when used on a gritty rope. I'm interested in whether or not it is a reasonable choice as a belay device, when you have a rope that will fit through it without too much trouble. There is one major advantage of an ATC for belaying: I go caving with a lot of people who know how to belay with ATCs, and in no other way.

ATC-like devices that can be rigged for auto-braking function, such as the ATC Guide and Petzl Reverso, would be useful in their own right if safe.

I would be reluctant--by which I mean unwilling--to use a figure 8 to belay on a cave rope. I'd use a Munter hitch on the figure 8's attachment carabiner first. A factor-1 fall on a UIAA semi-static rope produces up to the same peak impact force as a factor-2 fall on a UIAA single dynamic rope (12kN, by the standard). Figure 8 descenders are considered acceptable for belaying climbers on top-rope (where the absolute maximum fall factor is 1, but really it's always much less), but not for lead, because of they don't provide adequate braking friction. That suggests strongly that Figure 8 descenders are generally unsuitable for belaying on semi-static rope (or totally static polyester rope!), since fall forces for low fall factors on these ropes can be similar to forces experienced in a lead fall.

Some figure 8 descenders have small eyes large enough to be used as belay plates themselves. They tend to work like belay plates--just not as well. But if I'm going to be using a belay plate in a cave, I'd prefer to use a device that has that as its primary function.

It is also worth mentioning that the Petzl Pirana is not a belay plate--it is a figure 8 style descender that is designed to be used with "rapid style", i.e. the rope wrapped around the carabiner instead of the body of the device.

I still await an answer regarding the safety of belaying with an ATC or other belay plate on semi-static rope which may be wet and/or muddy. It sucks, but is it safe...
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Re: belay plates on cave rope

Postby dcfdrescue2 » Mar 29, 2008 6:08 pm

I know you are looking for info on belay plates, of which I have none, however, I am curious if the Tandem Prussik Belay (TPB) is used at all in the caving community. The TPB works well in a wide variety of environments and is a tested, rated system that is cheap as heck.
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Re: belay plates on cave rope

Postby ek » Mar 29, 2008 6:46 pm

The Tandem Triple-Wrap Prusik belay (for a good description, see pages 8-9) is commonly used in cave rescue. It is an essential part of NCRC training (see page 7). Its main advantages are that it reliably catches falling 2-person loads, and passes the "whistle test" (if the belayer is incapacitated, the T3WP belay still catches the falling rescue load). Its main disadvantage is that it is non-releasable when loaded, which makes it a method of secondary consideration for sport use, especially given the availability of the Munter hitch which is highly effective for belaying single-person loads, is releasable when loaded and doubles as a fixed brake lower, and is faster to tie than two Prusiks.

My specific interest in belay plates for belaying sport caving loads is that I know a lot of folks who only know how to belay this way. Some of them do so when caving, and I am wondering if it is considered safe.
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Re: belay plates on cave rope

Postby chrismc » Mar 30, 2008 10:49 am

Ah yes, I completely missed the "belaying" part of your question. All said, I guess I'd have to attack the validity of the test case. I'm not exactly sure what you mean by "sport caving loads". In my experience, there is not a need for an "active" belayer in SRT. There is a bottom belayer when one is rappelling, but when one is climbing there is not a belayer. This isn't to say that there couldn't be, but the general consensus among people I've ever caved with is that if you are going to ascend a rope, you know what you are doing. Having a second belay line could be disastrous for some long, gnarly drops with rope tangling issues. The only other situation I could see is an exposed traverse, which I would handle with a horizontally anchored work positioning, or safety line which would enable connection to your QAS. What exact usage did you have in mind?

Now if you are talking about climbing in-cave, my answer would be that I would not be using static caving rope, but climbing rope instead and the discussion is a moot point. I can't think of a good scenario where I would ever be taking a "fall" (FF anywhere close to 1.0) on caving rope. Having said that, I haven't crossed the "rock climbing in a cave" moral boundary yet, and still have the caving/climbing "separation of church and state" firmly ingrained in my psyche. Nonetheless, I would never personally put myself in a situation to take a FF2 fall on anything but nice, gooey dynamic climbing rope. I can't see a valid reason to ever mix an ATC with caving rope.

FWIW, I have used a Figure-8 for belaying a lead climber (and catching a lead fall), and I have never heard that it shouldn't be used for that. It will go through more rope to catch a fall due to less friction, but it certainly does catch the fall. It probably catches it more smoothly and with less force than an ATC as well (due to running through more rope ). Obviously you have to watch how run-out your climber is, and make sure he has enough pro in to avoid hitting the deck, but certainly usable. My preferred belay device is a Trango Pyramid, however. I will not use belay devices with moving parts (Grigri). I also think that the auto-locking devices encourage laziness and inattentiveness among the belayer- a view that any trip to a climbing gym would encourage.

All my opinion, though, no facts to back it up.
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Re: belay plates on cave rope

Postby ek » Mar 30, 2008 11:36 am

chrismc wrote:Ah yes, I completely missed the "belaying" part of your question. All said, I guess I'd have to attack the validity of the test case. I'm not exactly sure what you mean by "sport caving loads". In my experience, there is not a need for an "active" belayer in SRT. There is a bottom belayer when one is rappelling, but when one is climbing there is not a belayer. This isn't to say that there couldn't be, but the general consensus among people I've ever caved with is that if you are going to ascend a rope, you know what you are doing. Having a second belay line could be disastrous for some long, gnarly drops with rope tangling issues. The only other situation I could see is an exposed traverse, which I would handle with a horizontally anchored work positioning, or safety line which would enable connection to your QAS. What exact usage did you have in mind?

You'd want a belay when climbing a long ladder, or when you have one person who is adequately skilled to climb up natural feature, and others who feel uncomfortable climbing it without a belay.

I can't think of a good scenario where I would ever be taking a "fall" (FF anywhere close to 1.0) on caving rope.

This isn't really relevant to belaying, but such a situation would occur if you were clipped into either the first or last bolt on a traverse line and that bolt blew out. (In order for a traverse line to have a "last bolt", the anchor for the drop must not be backed up, except by the rest of the traverse line leading up to it--then the last bolt of the traverse line is the anchor for the drop. This situation happens occasionally, but this is only considered safe if the caver and rope would not be severely hurt by the failure of that bolt. More frequently, a traverse line leads up to two bolts.) The fall factor would not be 1, but it would be high. Though assuming you are clipped in with a cowstail, the cowstail should effectively reduce the fall factor. If you managed to take a fall of factor 2 onto this bolt with your cowstail, and it blew out at the peak impact force of your cowstail, then the cowstail would probably not be effectively absorbing much more energy when the second (or second-to-last) bolt in the traverse line arrests your fall--in this case, it really is just the cave rope that is absorbing the fall's energy.

Poor rigging could also cause you to experience a high fall factor due to the failure of one anchor component.

FWIW, I have used a Figure-8 for belaying a lead climber (and catching a lead fall), and I have never heard that it shouldn't be used for that. It will go through more rope to catch a fall due to less friction, but it certainly does catch the fall. It probably catches it more smoothly and with less force than an ATC as well (due to running through more rope ). Obviously you have to watch how run-out your climber is, and make sure he has enough pro in to avoid hitting the deck, but certainly usable.

I've always been taught that this is a no-no...however, looking at Petzl's and Black Diamond's manufacturer recommendations, it appears that they're OK with their figure-8's being used to belay lead climbers.

I guess if belaying a leader with hip belay is considered safe, belaying with a figure-8 should be considered safe as well.

I also think that the auto-locking devices encourage laziness and inattentiveness among the belayer- a view that any trip to a climbing gym would encourage.

I think that the use of Grigris at climbing gyms fails to imbue activeness and attentiveness in new belayers. People who learn to belay on Grigris tend to be awful belayers, at least until they've unlearned their bad habits. Whereas people who learn to belay with belay plates tend to be great at belaying with Grigris, since you can use exactly the same technique for belaying someone on toprope. This technique (where you return the rope to the braking position and keep a brake hand on the rope at all times) is even a superior technique for belaying with a Grigri, because it works even with a slippery rope or a rope that is thinner than the Grigri's specifications permit (within reason).

Since I view indoor climbing as practice for outdoor climbing, and outdoor climbing as the real thing (or as practice for caving), I think that folks who run climbing gyms should be more concerned about the effect of their Grigris on people's belaying skills that they would then apply in "real climbing." However, not everybody views it this way, and using Grigris is good for risk management...at least until the newfangled Grigri belayer, not understanding the concept of the "braking position", tries to lower the climber by pulling the lever without a brake hand on the rope...

Having a device with an auto-locking mode for belaying from above, however, is useful, because, without that, you have three options for belaying from above:

(1) Get in a stance where you will be able to comfortably operate the belay device, without a redirect, and belay normally. This is often not possible.
(2) Use a redirect, putting nearly twice the force on the anchor when the climber falls, and deal with the increased friction, and increased complexity, of the resulting system.
(3) Leave your belay device on you gear loop and belay your partner with a Munter hitch (if you know how). Hope you don't have to lower your partner, as the Munter imparts wear and (usually) twist to the rope.

Having a device with an auto-braking mode for belaying from above also enables you to have a hand free for rope management or any other task that needs to be done while belaying (e.g. holding pressure on that wound of yours...), and allows you to belay two seconds simultaneously on separate ropes or separate ends of the rope.

It is also worth mentioning that the ATC Guide and Petzl Reverso (and Reversino) do not have moving parts--they accomplish their auto-locking function in an entirely different way (skip ahead to "chapter 2").

I am curious as to why you categorically avoid devices with moving parts. Racks, as well as bobbins with spring clips for inserting the rope, are rappel devices with moving parts...
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Re: belay plates on cave rope

Postby chrismc » Mar 31, 2008 9:47 am

ek wrote:You'd want a belay when climbing a long ladder, or when you have one person who is adequately skilled to climb up natural feature, and others who feel uncomfortable climbing it without a belay.

I guess I'd view this as a safety issue. While I fully acknowledge that different cavers have different skill sets and who feel comfortable in different situations, I don't have the same feeling about safety. If its a safety issue, I tend to view it in black & white. Either its safe or its not. Is there exposure that could lead to an injury if an accident occured? If so, then precautions need to be taken. Accidents aren't usually foreseen, so be trusting someone's judgement that they will not have an accident, you are setting up for an incident. Within the "its safe" realm, there are many "right answers", and I'm good with agreeing to disagree as long as its safe.

ek wrote:Poor rigging could also cause you to experience a high fall factor due to the failure of one anchor component.

Good point.

ek wrote:
FWIW, I have used a Figure-8 for belaying a lead climber...

I've always been taught that this is a no-no...however, looking at Petzl's and Black Diamond's manufacturer recommendations, it appears that they're OK with their figure-8's being used to belay lead climbers.

I guess if belaying a leader with hip belay is considered safe, belaying with a figure-8 should be considered safe as well.

I have belayed with a hip belay before as well, under well-controlled circumstances. To help understand modern rope techniques, I think its important to fully understand the strengths and weaknesses of historical techniques, as this will help us use safe and efficient techniques in the future. I have also tested the Dulfersitz, or body, rappel. Man, are racks nice.

ek wrote:I am curious as to why you categorically avoid devices with moving parts. Racks, as well as bobbins with spring clips for inserting the rope, are rappel devices with moving parts...

While I have lots of answers for that (usually something about "more parts to break", "more things that can go wrong"), the truth is probably just a stubborn traditionalist ethic. If there's a bolt placed right next to perfectly good natural pro, there's a good chance I'll remove that as well. One of my pet peeves is a beautiful crack climb marred up with a bolt ladder.
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Re: belay plates on cave rope

Postby hunter » Mar 31, 2008 10:13 am

Ek,
Minor point but ATC type devices are generally refered to as belay tube devices ( http://storrick.cnchost.com/VerticalDev ... lates.html ). A belay plate is a different type and you don't see them much any more.

I've never seen it justified in the literature but for the scenario you describe an ATC should work fine. As long as it isn't 9mm the device will lock fine on static rope. The main issue I can see is that unlocking the device and taking in rope will be a bit sticky. I've seen static used for TR only in climbing gyms with ATCs (and Gri-Gris). The caveats I would worry about are:
-no slack when using static (as mentioned above)
-cave rope will eat an ATC fast if you have to lower or rappel on it
-check the diameter recommended for the device. The reverso doesn't work so well on 9mm rope. Petzl sells the Reversino specifically for thinner ropes.

For Auto lock with a Reverso/ATC Guide I am less certain and would have to try it. The auto lock feature will lock but may be tough to unlock. This is an issue if you rig such that the device and anchor are out of reach.

Gri-gri is also tough. I've seen it used for TR belay in gyms but I wouldn't use it in a cave due to the dirt and grit. First, it's possible to jam a gri-gri with sufficient dirt. Second, there was an incident a while back where someone was being lowered with a gri-gri attached directly to an anchor and placed in the dirt. As the individual was being lowered the rope broke at the belay device (and the guy was killed). The accident analysis finally concluded that either a piece of glass or a piece of metal was sucked into the gri-gri and cut the rope. They attempted to duplicate the scenario and hand fed glass into a gri-gri while lowering. They didn't get the rope to fail but got some spectacular damage (matching the actual damage0. Given the level of sharp crystal material in caves I would not be happy using a gri-gri.

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Re: belay plates on cave rope

Postby ek » Mar 31, 2008 10:39 am

chrismc wrote:I guess I'd view this as a safety issue.

I'd agree with that. That's the justification for belaying.

While I fully acknowledge that different cavers have different skill sets and who feel comfortable in different situations, I don't have the same feeling about safety. If its a safety issue, I tend to view it in black & white. Either its safe or its not.

I think that's a dangerous view to take. Different actions carry with them varying elements of risk. I think it distorts reality, and one's judgement of it, to pretend that there are exactly two discrete risk states. Is cave diving "safe"?

I have a friend who takes a black and white view of safety, in the sense that he engages in dangerous activities without recognizing that there is risk involved, and then when the risk gets to a certain level or he becomes aware of the risk, he starts freaking out because it's "unsafe." I know that you do not fit this description. Still, I think that, that you don't fit this description suggests that you really do cope with what you realize to be varying degrees of risk on a sliding scale.

Is there exposure that could lead to an injury if an accident occured? If so, then precautions need to be taken.

You mean like sending the most experienced person first? :big grin:

Seriously though, do you ever chimney without a belay? Imagine if you didn't--the person going first would have to place bolts on the way. This would entail an enormous increase in complexity and time, during which everybody else would be at risk of getting hypothermic, and during which everyone, especially the bolter, would be using up energy reserves, increasing the risk of someone making a mistake and getting hurt.

There are obstacles in caves that are easily bypassed by experienced cavers--with a real but minuscule chance of the obstacle causing injury--but which would be almost certain to trap an inexperienced caver, or someone who is not physically fit (e.g. keyhole-shaped passage). You can be walking upright, trip on a stone, fall, and break something. At what point does something begin to be considered unsafe?

Another example of a common practice that violates the notion of safe-or-unsafe is the use of handlines on exposed climbs. If a climb is unsafe without a handline, then in a certain sense it is also unsafe with the handline, in that you could accidentally let go of the handline. Still, the idea is that, with the addition of the handline, the climb is made easy enough to be deemed "safe enough."

Accidents aren't usually foreseen, so be trusting someone's judgement that they will not have an accident, you are setting up for an incident.

Overcomplication also sets everyone up for an incident. You have to find a happy medium, and ultimately, especially in a group of experienced cavers, what that translates into is each individual making personal judgements about what he or she feels comfortable doing.

There are three other situations where I think you'd agree that it is acceptable for one person to progress without a belay, and then to belay others. The first is when the belay is for progress capture rather than safety--for instance, if you have a difficult mud slope, but there is not a high probability of injury associated with sliding down it. Then it is reasonable to belay someone up it who has a great deal of difficulty climbing it, because it increases the overall efficiency of the team--they would take so long to get up it without a rope to rest on and use for stability that the increased complexity if setting up the belay is justified even though it doesn't protect against any credible threat to the person's safety.

The second is where there are two paths to get to a destination, and one is exposed but not difficult, and the other is not exposed but difficult. At least for some people. For instance, in Knox Cave in NY, to get past a certain point in the cave, there is an exposed climb, or a tight vertical squeeze where you have to remove your helmet and exhale to get through. Some people simply cannot make it through the Lemon Squeeze in Knox Cave, so if that is the case, they can be belayed up the exposed climb by someone who has made it through.

The third is when someone insists on a belay on territory that you'd think nobody in their right mind would want a belay on. Simple solution--provide the belay.

chrismc wrote:
ek wrote:I am curious as to why you categorically avoid devices with moving parts. Racks, as well as bobbins with spring clips for inserting the rope, are rappel devices with moving parts...

While I have lots of answers for that (usually something about "more parts to break", "more things that can go wrong"), the truth is probably just a stubborn traditionalist ethic.

But why do you use a rappel device that has moving parts? Just because it's been around for a long time?

chrismc wrote:If there's a bolt placed right next to perfectly good natural pro, there's a good chance I'll remove that as well. One of my pet peeves is a beautiful crack climb marred up with a bolt ladder.

I hope, in cases where there is no blanket permission to modify exiting protection, that you ask the landowners first!
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Re: belay plates on cave rope

Postby NZcaver » Mar 31, 2008 11:21 am

hunter wrote:Gri-gri is also tough. I've seen it used for TR belay in gyms but I wouldn't use it in a cave due to the dirt and grit. First, it's possible to jam a gri-gri with sufficient dirt. Second, there was an incident a while back where someone was being lowered with a gri-gri attached directly to an anchor and placed in the dirt.

I read about that incident. Not to split hairs too much... but if an "automatic" belay device like the GriGri, I'D, Cinch, SUM, etc is used properly, the device should be in a position where it is not resting on the wall/floor etc. The same applies with any belay device really. Plus the belayer's control hand (which always stays on the rope and is usually gloved in a cave environment) should effectively clean the rope of large debris before it has a chance to be fed into the device.

I've used my GriGri on 11mm static rope in controlled (single person load) circumstances, and have no major qualms with it used this way. When I've tried my ATC on the same rope, I've been a lot less happy with the results - both when rappelling and belaying carefully (ie from the top of a ladder climb). Of course ATC's handle nicely on supple dynamic ropes, which they are designed for. The GriGri, I think, is more forgiving of the handling properties of 11mm static rope than most tube/plate belay devices.

Of course if your standard caving descender is a Stop (or similar), you could just belay with that. Otherwise use a Munter hitch on a carabiner. Either way, the belayer obviously needs to pay close attention and keep slack to a minimum.
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Re: belay plates on cave rope

Postby hunter » Mar 31, 2008 12:01 pm

I read about that incident. Not to split hairs too much... but if an "automatic" belay device like the GriGri, I'D, Cinch, SUM, etc is used properly, the device should be in a position where it is not resting on the wall/floor etc. The same applies with any belay device really. Plus the belayer's control hand (which always stays on the rope and is usually gloved in a cave environment) should effectively clean the rope of large debris before it has a chance to be fed into the device.


True enough. I suspect the design of the gri-gri will still tend to increase damage to the rope when sharp grit goes through it. Of course this is also more of a concern when you are lowering or rappelling (as opposed to a TR belay).

I looked for the article to post a link to and the page google comes up with doesn't work anymore. It was a good report I thought.

The GriGri, I think, is more forgiving of the handling properties of 11mm static rope than most tube/plate belay devices.

Yeah, the ATC is sticky on 11mm (it will still lock though). This is where the manufacturers specs come in. The gri-gri is made for larger ropes and tube type devices vary. I would expect the Reverso to handle well on 11mm cave rope but it shouldn't be used on anything under 10.

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Re: belay plates on cave rope

Postby ek » Mar 31, 2008 12:04 pm

hunter wrote:Ek,
Minor point but ATC type devices are generally refered to as belay tube devices ( http://storrick.cnchost.com/VerticalDev ... lates.html ). A belay plate is a different type and you don't see them much any more.

Good call. Belay tubes are related to belay plates and operate on the same principle, but they are different types of devices. Thank you!

I've never seen it justified in the literature but for the scenario you describe an ATC should work fine. As long as it isn't 9mm the device will lock fine on static rope.

Then 9mm should lock fine too, so long as the belay tube permits 9mm dynamic rope, right?

I've seen static used for TR only in climbing gyms with ATCs (and Gri-Gris).

I hope it was semi-static!

NZcaver wrote:Of course if your standard caving descender is a Stop (or similar), you could just belay with that.

I've used a Petzl Stop as a fixed brake lower with 9mm cave rope. It slipped a lot--I had to tie it off to keep it from slipping. I'd be worried about its ability to catch a load in time on thin cave rope.
Eliah Kagan
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Syracuse University Outing Club

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ek
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