/ Caving near-miss using toothed cam pulley

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grunkalunka - on 21 Sep 2012
So I had an exciting near miss during an introductory caving trip recently and wondered if anyone had any views / comments:

A group of four of us are taking it in turns to ascend a fixed ladder under instruction from the guide, with each person tied to the end of a safety rope running up through what I understand to be a toothed cam pulley on a fixed belay. At the top of the ladder the guide is taking in the rope and explaining that if anyone falls then the pulley cam will catch them. As way of example he suggests to the last person ascending the rope that they lean back, at which point the rope runs clean through the pulley with the toothed cam bouncing up and down and the poor beginner bounces his way down only to be caught by the guide mere inches above the ground. Thankfully serious injury was avoided.

Now the guides quick reaction in managing to grab the rope (also thankfully injury free) definitely saved the chap who fell from a couple of broken legs but it was definitely a very close thing and could have easily been much nastier. A few seconds later and (apart from hitting the ground) I very much doubt anyone would have been able to hold the rope at speed. There was no back-up to the pulley and probably a foot of slack rope between the chap who leant back and the pulley. I also reckon there would have been a fair bit of slack rope between the guide who was belaying and the pulley. The pulley was something similar to this http://www.petzl.com/en/pro/progress-capture-pulleys/pro-traxion with some really mean teath, so I don't think it's similar to the old GriGri problem I've heard of where the rope would sneak through if your fall started off slowly.

Anyone any experience of using these pulleys before for anything other than hauling gear? Any suggestions for ways the system should have been backed up? It seemed a bit risky to trust just one pulley - granted a belay plate is a bit similar but at least you always have that locked off, whereas from the look of it the toothed cam on the pulley would only bite if shock loaded hard.

Iím just a lowly sport climbing boulderer so my technical rope work is rudimentary at best, so comments appreciated.

IPPurewater on 21 Sep 2012
In reply to grunkalunka: The pulley is not a belay device ! In my opinion it should not have been used in this case. I would have used an Italian Hitch or a belay plate.

Choose your caving partners carefully. It is much more difficult to rescue someone in a cave than it is above ground.

IPP
butteredfrog - on 21 Sep 2012
In reply to grunkalunka:

Not sure on your leaders thinking here; Italian hitch and a bit less reliance on the metalwork would be my choice!
butteredfrog - on 21 Sep 2012
In reply to IPPurewater:
> (In reply to grunkalunka) The pulley is not a belay device ! In my opinion it should not have been used in this case. I would have used an Italian Hitch or a belay plate.
>
> Choose your caving partners carefully. It is much more difficult to rescue someone in a cave than it is above ground.
>
> IPP

+1

biscuit - on 21 Sep 2012
In reply to butteredfrog:

+2

Italian hitch for me. A belay device in guide mode would give him the 'locking off' he seemed to want.
grunkalunka - on 21 Sep 2012
I'm beginning to wonder if he thought that the pulley had been locked off - it definately had a latch to catch and lock the cam down onto the rope - in which case the second might leant back before he'd had a chance to check it. Still doesn't sound like the best of ideas though, and relies heavily on the performance of one piece of gear.
Andy DB - on 21 Sep 2012
In reply to grunkalunka: Yes not a belay device so not designed to hold a fall suspect the cam has difficulty to engage at high rope speeds. This device does what it says on the tin 'progress capture' which means won't allow a loaded rope to return though it. I also believe you can lock the cam out the way so could have also been user error?
matthewtraver - on 21 Sep 2012
In reply to grunkalunka:

Damn... that seems like a pretty stupid idea on the guide's part. I've only ever used a munter/Italian hitch or a Petzl Stop underground. I've seen mini-traxions bounce and jitter on hauls before to the point where cam tooth sort of over extends itself and misses grabbing the rope. That could've been what happened?
jkarran - on 21 Sep 2012
In reply to grunkalunka:

> Anyone any experience of using these pulleys before for anything other than hauling gear? Any suggestions for ways the system should have been backed up? It seemed a bit risky to trust just one pulley.

In my experience (Minitraxion) they're very reliable so long as the rope is running the right way and the cam is not locked up in freewheel position.

Firstly are you sure it was rigged right with the cam on the rope and in good order, not full of mud?

Secondly I don't see how anyone could catch a fast-falling caver by hand using a rope without injury. Are you certain that's what actually happened, not that the retracted cam snagged the flailing rope and dropped into its active position or that the belayer had failed to take in the slack.

I don't mean to question your honesty, I just can't see that what you saw is actually what you described. Were you underground in the dark? How much of this did you see up close, how much was described to you by someone potentially covering their own back? What was the actual device used? What action has the guiding company taken?

jk
grunkalunka - on 21 Sep 2012
In reply to jkarran:

Aprpeciate the comments - not going to mention locations / guides / companies for exactly the point you make, that it was dark and I wasn't belaying, so it's down to memory and recollection!

Definately wasn't full of mud from where I was sitting next to it, but it could well have been that the cam was stuck on some grit or dirt and is why it didn't bite (had a look at it while the guide was taking a breather with the guy who fell and the action of the cam gelt smooth but very slightly gritty - but would have thought they are designed for this).

Im my opinion he was lucky to catch the guy and ended up with his hands basically jammed against the pulley - was wearing thick rubber gloves so may have given him a bit of protection / or made it harder to stop the rope running through his hands?

unclesamsauntibess - on 21 Sep 2012
In reply to grunkalunka: the "guide" sounds like a proper Munter. Pun intended.
alastairbegley - on 21 Sep 2012
In reply to unclesamsauntibess:
there are also other serious implications to using a device which can't be freed while loaded underground. As you really don't want to be hanging off a belt very long at all, if there is water involved and you can't be freed and get stuck under a waterfall it can and has caused fatalities in the past
Stuart (aka brt) - on 21 Sep 2012
In reply to jkarran:
> (In reply to grunkalunka)
>
> [...]
>
> In my experience (Minitraxion) they're very reliable so long as the rope is running the right way and the cam is not locked up in freewheel position.
>
> Firstly are you sure it was rigged right with the cam on the rope and in good order, not full of mud?
>
> Secondly I don't see how anyone could catch a fast-falling caver by hand using a rope without injury. Are you certain that's what actually happened, not that the retracted cam snagged the flailing rope and dropped into its active position or that the belayer had failed to take in the slack.
>
> I don't mean to question your honesty, I just can't see that what you saw is actually what you described. Were you underground in the dark? How much of this did you see up close, how much was described to you by someone potentially covering their own back? What was the actual device used? What action has the guiding company taken?
>
> jk

Have to agree with this.

The Traxions are used extensively in underground situations (from personal, instructed, and rescue use); the manner in which you describe its use - a lifeline belay on a ladder ascent - is very common (and I'd say de-facto in the Dales for instructed groups).

My bet is is the unit (presume Traxion as you weren't specific) was threaded wrong, with a very unlikely second scenario being the "guide" got to actuate the cam if it had been in its free running pulley mode (personally I don;t think they would have time).

Whether using Stops, Grigri's, Traxions as a belay it's definitely worth checking it "lock" the way it should when load is applied.

Mark Reeves - on 21 Sep 2012
In reply to Stuart (aka brt): Traxions were never really designed to take a dynamic fall. Because there was slack in the system although on top rope the fall was still dynamic.

The post above mentioned it being threaded the wrong way, I do doubt that as the guide wouldn't have been able to take in the rope.

They were design to haul and could be used in a rescue situation, but personally I would never use them to belay a person climbing due to the risk of a dynamic fall. A gri-gri would be much better and worked just as well in that scenario, it is also designed to take a dynamic fall.
Stuart (aka brt) - on 22 Sep 2012
In reply to Mark Reeves:

Agreed their design isn't intended for dynamic belaying, though it's somewhat moot as cavers use low stretch rope. Using it in this way is "within its limits". So the mantra is no slack as you don't want a fall; hence it's not illogical to use mechanical grab devices - it's pretty much standard for CIC and canny level 2s.

By threaded wrong I should have been clearer; with the cam disengaged.

A technical debate on kit isn't needed here I suspect, user error (as it so often is) would be my guess still.
muppetfilter - on 22 Sep 2012
In reply to Mark Reeves: The traxion is not a very suitable piece of kit for rescue (other than in place of a jammer) The one way nature and the fact it can't be released under load makes it a bad choice for a belay device.
Stuart (aka brt) - on 22 Sep 2012
In reply to muppetfilter:
> (In reply to Mark Reeves) The traxion is not a very suitable piece of kit for rescue (other than in place of a jammer) The one way nature and the fact it can't be released under load makes it a bad choice for a belay device.

They can be released under tension.
phizz4 - on 22 Sep 2012
In reply to grunkalunka: As the guide was at the top of the pitch he would have had to disable the toothed cam in order to lower the rope back down for the next climber. The likely hood is that he did not then re-engage the cam beofre the last client began to climb. The traxion is not like a gri-gri, it's toothed cam has to be manually engaged/disengaged. You can release it under tension but it is not an easy/rapid action.
HardenClimber - on 22 Sep 2012
In reply to Foxy:
> (In reply to unclesamsauntibess)
> there are also other serious implications to using a device.....

Devices like this are used for belays (hopefully with a dynamic rope rather than a semi-static srt rope, but it's easy to see where that can get muddled)on situations like ladders where there should only be a short fall.

Whilst they can be freed it needs some planning & thought. The hang may 'awkward' to get at and there may be real time pressure (person hanging in a waterfall), waist belt (often used still). They are not a simple fix to belaying ladders etc.

(did the rope get damaged?)
(given rigging at pitch heads the rope may have had some drag on it so the 'free' running may not have been a bit slowed)
deepsoup - on 22 Sep 2012
In reply to Stuart (aka brt):

> The Traxions are used extensively in underground situations (from personal, instructed, and rescue use); the manner in which you describe its use - a lifeline belay on a ladder ascent - is very common (and I'd say de-facto in the Dales for instructed groups).

Are ladders descended by groups as well as ascended?
OwenM - on 22 Sep 2012
In reply to grunkalunka: Surely, if your using a toothed device like this where there's a lot of slack in the system, there's a danger of the teeth ripping the sheath. This has happened in the past with people using jummers on a back rope when soloing. The result was the jummer (and climber) sliding down with the sheath whilst the mantle part of the rope stayed where it was.
David Coley - on 22 Sep 2012
In reply to OwenM:
> (In reply to grunkalunka) Surely, if your using a toothed device like this where there's a lot of slack in the system, there's a danger of the teeth ripping the sheath. This has happened in the past with people using jummers on a back rope when soloing. The result was the jummer (and climber) sliding down with the sheath whilst the mantle part of the rope stayed where it was.



Do you have a link to a first hand report of that? Thanks.
stonemaster - on 22 Sep 2012
In reply to OwenM: Hmm. Hard to visualize this. The mantle is the sheath while the kern is the core. It should have been the kern remaining intact while the mantle is sliding down after being ripped, perhaps?
JamButty - on 22 Sep 2012
In reply to Mark Reeves:
> (In reply to Stuart (aka brt)) Traxions were never really designed to take a dynamic fall. Because there was slack in the system although on top rope the fall was still dynamic.

+1, this to me is all about dynamic failure. On a static lockoff process this pulley is ok, but not where there could be any stretch. The only time I've ever used camming teeth underground is on the ascenders, which again lock off when you are static.
Belays again as others Italian hitch usually.
Glad noone was injured....
Stuart (aka brt) - on 22 Sep 2012
In reply to JamButty:

We'll never know what happened; some facts on the kit though.

Reading the manual for the Traxion (certainly the Pro version) testing at FF 0.5 on 10+mm ropes low stretch didn't rip the sheath.

At FF 1 ripping of the sheath at circa 5.5Kn for 10+mm rope. But this in itself is moot as we're talking about lifelining a ladder... a FF1 equals hitting the deck!

As for ascending on jammers: ever stopped to think what would happen if that rebelay above your head failed? The closer you get their is an increase in FF. It's why a rule of thumb is if a rebelay is needed less than five metres from the pitch head or another rebelay, you'd place two bolts (not to say this happens).
OwenM - on 23 Sep 2012
In reply to David Coley:
> (In reply to OwenM)
> [...]
>
>
>
> Do you have a link to a first hand report of that? Thanks.

No I can't think where i read it now, it was a long time ago maybe early seventies.

needvert on 23 Sep 2012
Of note:

If minitrax is fine enough for solo top roping...
Dave Williams - on 23 Sep 2012
In reply to Stuart (aka brt):
> (In reply to jkarran)
> [...]
>
>
> The Traxions are used extensively in underground situations (from personal, instructed, and rescue use); the manner in which you describe its use - a lifeline belay on a ladder ascent - is very common (and I'd say de-facto in the Dales for instructed groups).
>

As a long-time caver in the Dales, I'd agree with the above. They're widely used by CICs and L2s.

I've always wondered at the continuing fascination with teaching beginners to climb ladders. Ladders do still have their (very limited) use in caving admittedly but it's far more sensible to teach beginners SRT from the very start. This can be done above ground, in daylight, using pre-rigged trees, towers etc. This is obviously safer as you take darkness and unfamiliar surroundings out of the equation. Even lifelining ladders could be done above ground initially. It always concerns me when I see groups being shown how to turn their caving lights on, then disappearing underground with ladders, Traxions etc.

FWIW, I agree with others on this thread and think the OP's experience is simply down to some form of human error.

Dave

jimtitt - on 23 Sep 2012
In reply to David Coley:
> (In reply to OwenM)
> [...]
>
>
>
> Do you have a link to a first hand report of that? Thanks.

You can read this one about how cavers die (mis)using ascenders. http://www.caves.org/section/vertical/nh/45/ivyaccrpt.html

David Coley - on 23 Sep 2012
In reply to jimtitt: Sad story.
ads.ukclimbing.com
Oceanrower - on 24 Sep 2012
In reply to Dave Williams:
> (In reply to Stuart (aka brt))
> [...]
>
> As a long-time caver in the Dales, I'd agree with the above. They're widely used by CICs and L2s.
>
> I've always wondered at the continuing fascination with teaching beginners to climb ladders. Ladders do still have their (very limited) use in caving admittedly but it's far more sensible to teach beginners SRT from the very start.


Not done much on the Mendips then?

Of the many, many caves, I can only think of Thrupe Lane, Rhino Rift and Hunters Hole where you would use SRT over a ladder.


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