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WC Ropeman as crevasse rescue pulley?


Coldfinger

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Seeing as Denali season is getting underway, I was wondering about something I've run across and though it'd be a good time to post it here and not the Gear Critic.

 

So..... I have run across a rescue set up where the primary pulley (i.e. the one attached directly to the anchor in a z system) has been replaced by a Ropeman.

 

Any of you have any experience with this?

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First thought is that rope diameter may be a factor. WC Ropeman is only designed for use ropes to 8.5mm, so the 8.1mm Rando is out. The Petzl MiniTraxon goes to 8 mm.

 

Some thought would need to be used on how you could release tension with a device like this in the event of a tricky crevasse lip, if that became necessary.

 

Personally, I've just used the standard prusik knot.

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No experience, but I can't imagine that it would be very efficent as the rope would have to run over the cam, not a pulley, unless there is some kind of modification. A Petzl Minitraxion would be ideal as the primary pulley IMNSHO.

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I was initially skeptical, but it occurred to me that folks use biners as pulleys, so why not the ropeman.

 

Well, I'm sure it would work, but pulleys are more efficient than carabiners and I would bet the ropeman as well. Assuming a two person system as per the link, I think hauling efficiency would be key. With more hands to pull that becomes less important.

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Seemed weird to me but it's here: Link

 

I was initially skeptical, but it occurred to me that folks use biners as pulleys, so why not the ropeman.

 

That system does have the advantage of a c pulley to the fallen climber.

 

interesting link.

The last time I looked into these things, I thought the canadian mtn guides assoc taught to do crevasse rescue this way and called it the drop c?

 

With the assumption of a frictionless system and a force of one unit on the pulling end, the ropeman in the drop c setup would be experiencing 2 unit of force pulling onto the anchor. With a normal z-c setup, the anchor pulley would feel a unit force of 4. When you think about the friction that gets involved with twice the unit of force pulling on it, you can see that the drop c setup makes the ropeman less of a concern than in the zc setup.

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With the assumption of a frictionless system and a force of one unit on the pulling end, the ropeman in the drop c setup would be experiencing 2 unit of force pulling onto the anchor. With a normal z-c setup, the anchor pulley would feel a unit force of 4. When you think about the friction that gets involved with twice the unit of force pulling on it, you can see that the drop c setup makes the ropeman less of a concern than in the zc setup.

And that is why we have mathematicians.

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I wish I could describe the reasoning with the unit forces and how they multiply through the system but I need drawings to make sense of it. and I lack the computer wherewithal to do that quickly and logically. easy on a bar napkin though.

 

A physicist would be able to apply a real world friction to my system and give a better answer, but alas, I don't care that much.

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I was initially skeptical, but it occurred to me that folks use biners as pulleys, so why not the ropeman.

 

 

I don't know if you've actually tried to use a system that uses biners as pulleys or not, but in my experience, using biners instead of pulleys sucks. Particularly with just a couple of people trying to do the pulling, the friction of the biners makes pulling really really hard if you're actually trying to haul someone up.

 

My solution is to use Revolver carabiners instead of pulleys. The decrease in friction is very significant. (With two people pulling, it can make the difference between being able to actually lift the victim and not being able to lift him.) Revolvers have other uses as well, so they aren't single purpose crevasse rescue gear like pulleys.

 

 

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Was thinking of using the revolver on the z, but coming back to the haulers or on the loop if I happen to be in the crevasse.

 

Have the ropeman anyway and then stumbled on that diagram using it as a ratchet instead of a pulley and fill in the blank prussik or tibloc.

 

Never seen that one before.

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If anyone hasn't seen it yet, check out the Micro (not Mini) Traxion for this job. It's the total shizz!

 

+1

Wow! Half the weight at 3 oz. In addition to the crevasse kit, it could be used to haul packs on the hard pitches. Nice find!

Edited by DPS
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$95 bucks...

 

Hey goobers, take a standard pulley apart, go down to NAPA, buy a closed sealed bearing and save yourself $50. If NAPA is too far for your butt to go, and you are sitting your ass down at the computer go to Grainger.com, or MSC.com, or Bergbearing.com, or ... mcmaster.com and buy a damned closed sealed bearing.

 

Or be smarter yet and buy a cheaper, LIGHTER, NON SEALED bearing that is just as good. Oh no, once every 10 years you might have to grease the bearing! Of course no one actually uses their pullies except once in a blue moon so the one grease job that they got in the factory will be perfectly good for any crevasse rescue you will participate in in the next 30 years.

 

NOW, if you are a guide and are teaching folks ALL THE TIME and therefore USING your pullies ALL THE TIME, then yes, it might make sense to go to a closed bearing system. If you are not a guide, don't waste your $$$ on a closed bearing. Get the cheaper bearings. Likewise the DRY OPEN bearings will have higher throughput in terms of EFFICIENCY than any closed bearing, but will not last as long.

 

You did notice that Petzl posted their bearings "efficiency". They did this because its piss poor and therefore made it a selling point since few know better!

If Petzl were actually selling these buggers to actual CLIMBERS instead of RESUCE Personnel they would be selling open higher efficiency bearings.

 

Petzl must be laughing all the way to the bank every time some ignorant sucker buys one of these things.

 

Don't be a stupid ignorant sucker.

 

PS. 2 biners/garda hitch act as a far better ratchet, therefore don't need another piece of equipment via the ropeman. Heck a prussic works fine, and it releases unlike a ropeman or this overpriced hunk of junk from Petzl.

If anyone hasn't seen it yet, check out the Micro (not Mini) Traxion for this job. It's the total shizz!
Edited by Wastral
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Hey goobers, take a standard pulley apart, go down to NAPA, buy a closed sealed bearing and save yourself $50.

 

I must be a goober because I'm not clear on the bearing issue. Will a closed sealed bearing give you the same functionality of the pulley and rachet combo of the Micro Traxion? Do closed sealed bearings only rotate in one direction or something?

Edited by DPS
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Hey goober, I am NOT going down to NAPA to buy something I will be using far more often as an ascender or top rope self belay than to haul somebody out of a crevasse so that's why I wanted to avoid buying a pulley I ain't likely to use more than once in a while (never mind carrying a pulley around everywhere). I already got me a revolver and a ropeman, so no cash was the idea.

 

Minitraxions are the shiz for that too, don't wanna buy one tho.

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I already got me a revolver

 

The Revolvers seem pretty ideal, any idea of how well the rope tracks in the pulley in z haul systems?

Should track fine, just not the most efficient diameter, I'd bring one mainly for rope drag on long leads on one rope.

 

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I already got me a revolver

 

The Revolvers seem pretty ideal, any idea of how well the rope tracks in the pulley in z haul systems?

 

It doesn't generally.

 

As far as I know from what I have read and looked at from pictures and peoples usage descriptions, ropemans and this widget from petzl cannot be released when under tension as they are a cam device. Are you trying to kill your partner in the crevasse that you just hauled up under a lip?

 

I can see how said widget would be useful for rockclimbing(pack hauling), but for crevasse rescue? Ug, no. Already are carrying gear that does this function anyways. Why would I carry yet another heavier piece of gear? Its 2oz's for Pete's sake.

Edited by Wastral
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Mainly as the ropeman, minitrax or even prussiks are also great for climbing out of a crevasse. Known and seen folks fall in but none got pulled out. Not that I would ever be unprepared for a rescue, but as a two man team you'd better get yourself out. Kinda seems folks tend to forget that and emphasize hauling in these topics.

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As far as I know from what I have read and looked at from pictures and peoples usage descriptions, ropemans and this widget from petzl cannot be released when under tension as they are a cam device. Are you trying to kill your partner in the crevasse that you just hauled up under a lip?

 

I can see how said widget would be useful for rockclimbing(pack hauling), but for crevasse rescue? Ug, no. Already are carrying gear that does this function anyways. Why would I carry yet another heavier piece of gear? Its 2oz's for Pete's sake.

 

Hey Wastrel, I'm not fully sure what you are saying about going to Napa. Do they have some kind of ulta-light bearings with the concave we all like so that the rope tracks in it? And we should go get that? It weighs less than 2oz? Can you post a link and a picture of this so the rest of us can get up to speed.

 

As far as your statement that you can't be backing off one of these in a Z-pulley situation, why couldn't you just pull the rope a fraction of an inch up and easily just release the cam to lower so that your buddy doesn't get his head whacked on the lip of the crevasse, as you say? I will admit I just got mine and have only used it 2 times, neither to pull a dude out of a crevasse:-)...hopefully never have too...but I didn't even try to set it up for that either. Why can't you release just the cam? I'm not clear on that either.

 

$95 bucks...

 

Hey goobers, take a standard pulley apart, go down to NAPA, buy a closed sealed bearing and save yourself $50. If NAPA is too far for your butt to go, and you are sitting your ass down at the computer go to Grainger.com, or MSC.com, or Bergbearing.com, or ... mcmaster.com and buy a damned closed sealed bearing.

 

Or be smarter yet and buy a cheaper, LIGHTER, NON SEALED bearing that is just as good. Oh no, once every 10 years you might have to grease the bearing! Of course no one actually uses their pullies except once in a blue moon so the one grease job that they got in the factory will be perfectly good for any crevasse rescue you will participate in in the next 30 years.

 

NOW, if you are a guide and are teaching folks ALL THE TIME and therefore USING your pullies ALL THE TIME, then yes, it might make sense to go to a closed bearing system. If you are not a guide, don't waste your $$$ on a closed bearing. Get the cheaper bearings. Likewise the DRY OPEN bearings will have higher throughput in terms of EFFICIENCY than any closed bearing, but will not last as long.

 

You did notice that Petzl posted their bearings "efficiency". They did this because its piss poor and therefore made it a selling point since few know better!

If Petzl were actually selling these buggers to actual CLIMBERS instead of RESUCE Personnel they would be selling open higher efficiency bearings.

 

Petzl must be laughing all the way to the bank every time some ignorant sucker buys one of these things.

 

Don't be a stupid ignorant sucker.

 

PS. 2 biners/garda hitch act as a far better ratchet, therefore don't need another piece of equipment via the ropeman. Heck a prussic works fine, and it releases unlike a ropeman or this overpriced hunk of junk from Petzl.

 

Have you actually used this? Seem to me that the friction you'd get would be crazy high. To the point where you'd just unrope and leave yer buddy stuck upside down in the crevasse. If that's the case, it might be better to map out a route that doesn't involve any big crevasses and leave all this junk at home? Or be like John Frieh and go so fast (and light) over them that the crevasses don't feel yer weight:-)

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Bill is your post for real? Ok, try the obvious 101. Bearing goes INSIDE the pulley. They are standard sized. Likewise standard drill sizes fit their OD's if you wish to change standard bearing size, unless you want a 100% press fit. Not needed in this case though. Sealed bearings are heavy. Non sealed non greased bearings are lighter and have higher efficiency. Its not like they don't have shields, they do, they just aren't waterproof shields. Who cares if water gets in? You do if you use it all the time because over time said water will bring dirt as well and EVENTUALLY, the efficiency of the non shielded bearing will have an efficiency lower than the closed greased bearing. Oh no, you mean I gotta clean it once every blue moon!

 

Why can you NOT release in a crevasse situation using a cam device? Really? What is going to stop the whole danged rope from swishing through? Once the cam lets go there is nothing stopping the puller from dropping the guy in the crevasse and the rope down to never never land. THAT is why you want a prussic. That being said. If said cam device cannot be locked open like the ropeman, then its possible to use. That petzel one can be locked open and Poof goes your buddy into never never land as you are desperately trying to flick that tiny little lever with frozen gloves to get it to engage and take the pressure off of you the puller. Add in that cams stop something VERY HARD putting large stresses on your snow anchor which is already marginal to start with as its in puff snow and well... Hard snow or ice? Pff, haul a tank on it. Soft snow. Yikes. Barely touch it and it moves.

 

Yes, in any situation its always faster for the guy in the hole to get himself out. 2,3 man is the same. With 4 guys on a team its probably faster to just have the 3 haul the typical guy out all of 5 feet while he helps a bit. Actually 3 man is worse. You can have 2 guys dangling in the hole instead of only 1. Naturally, the mountaineers who seem to teach everyone around here, don't bother to teach how to undo this situation... IE if you can do the 1 or 2 man in the hole with YOU and only YOU up top, then one is prepared. Unless one knows this they are not prepared. Likewise they teach everyone to pull on the rope with their arms... 1 guy squatting can generate more power and force than any 2 guys pulling with their backs and arms.

 

Its a damned good thing that very few actually fall into crevasses. 75% of folks don't know their ass from their elbows who supposedly "do".

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