Hello!

Well, for the Fixe pulley that is. Here's a link to the 'owner's' manual for the Fixe pulley. I know this is the current manual, because I just bought a new Fixe yesterday and the paper manual that came with it is the same as this electronic version in the link below - taken directly from Petzl's website:

http://www.petzl.com/files/all/technica ... 5450-F.pdf

Take a look at the left diagram on page 2 that shows a Fixe pulley being used with a Petzl Basic as a progress capture system. BTW, peripheral to the topic, the diagram also shows one of the unique ways a Fixe can be connected - note how the two carabiners interlock.

First let's be sure what's what in the diagram. Going by the diagram on the right and the force comparison table, it is inescapable that the weight represents the load and is designated as 'P' in the force comparison table, and the force we have to pull with is designated as 'F'.

So what's wrong? The capture device is on the wrong side of the pulley!!! If the pull rope is released, the ascender will clamp to the rope, but the weight will pull the ascender toward the pulley creating a 'blocking' stop. But what makes this arrangement not only bad and wrong, but dangerous as well, is that the ascender can move on the carabiner and get into some really awful binds that may very well damage the ascender resulting failure and loss of the load.

If you check the other two diagrams, they are also wrong. And we believe the manufacturer recommendations, because they're always right and they test all the configurations they recommend.

Do you mean the illustration labeled:

'Simple hauling system with anti-slip lock'

if not, what is the illustration label?

There are three illustrations on the second page showing with progress capture - all three are all wrong.

This is fairly acceptable and that the drawings are correct. For (uncited) reference I have seen this method described in at least two different caving texts, in addition to the Petzl documentation.

Have you tried this out in practice?

Here is one of the lines of reasoning to to run the hauls like this: The carabiner which connects the ascender to the pulley is not in a life support role, other than holding the ascender up. If the ascender is run to hold the rope in tension (on the other side of the pulley than is shown in the petzl diagrams) then the carabiner is essential. When hauling, the ascender will run up the rope and can do all sorts of strange things - possibly loading the carabiner gate or twisting. When the load is re-applied to the ascender (e.g. when resetting the haul system) the system might load the gate of the carabiner or a twisted ascender, compromising the ability of the ascender/system to hold the load.

Yes, I did try it. The ascender got in an awful twisted, disoriented bind. The following is a quote from the caving rescue book, "Life on a Line" by Dr. Dave Merchant:

"…we come to the infamous “Fixed side pulley method” promoted by Petzl (but many others produce ‘tribute’ models to the Fixe pulley these days). Here the pulley’s fixed sides are put to advantage by crossing two karabiners – one for the anchor and one for the rope clamp. Now that’s fine so far, but what many people then do is put the rope clamp in compression (it’s in the product instructions, which doesn’t help!).

The explanation is that the karabiner connecting to the rope clamp sits astride the body of the pulley and so can’t rotate, and that’s true to a limited extent. What can still happen, and does with a$$-quaking regularity, is the rope clamp migrates around the karabiner instead, lifting it up, twisting it round and ruining your day. Not only is this a gate-loading problem it can get so rammed up against the pulley that you can’t shift it. It’s just as easy to put the rope clamp in tension (photo to the right), and use the same preventative methods we’ve talked about above."

The part I put in bold – exactly what happened the first time I tried it.

This first pic shows the orientation of the ascender under 'ideal' conditions (Sorry about the background clutter) Even under hoped for operation, the orientation of the ascender and the cam is horrendous:



Here's what can easily happen (what Dr. Merchant described) - I don't want my life hanging on this and I didn't show it 'migrated' to the gate side of the biner which would apply pressure to the gate:


Then there are the less spectacular issues as shown in the next pic. What I'm showing here is notice the pulley does not swing fully inside the biner. That's because the curvature of the biner interferes with the holes in the pulley preventing free rotation and a bind:


A possible remedy would be to use a larger biner as shown in the next pic. Well that fixes the pulley binding, but now look what's happening at the ascender connection - now it's in a bind:


And finally a pic of a simple solution to the tension configuration to keep the ascender from 'riding' up the rope when you take in rope:


I guess the point is that even with the best outcome with a compression configuration, first pic, the orientation of the ascender, the relationship of the rope, cam, and housing is quite questionable. I don’t know of anyone that would want their life hanging on that.

The simple weight minimizes, if not completely eliminates, the cross-loading, etc. in the tension configuration. Another solution would be tape or lashing with cordage or even throwline to secure the biner in a stable position.

"The simple weight minimizes, if not completely eliminates, the cross-loading, etc. in the tension configuration. Another solution would be tape or lashing with cordage or even throwline to secure the biner in a stable position."

Wouldn't a friction hitch combined with a prussik minding pulley do the same thing without the concern of cross loading/locking? That's all that I have ever done when needing to configure a tackle.

Sure, a prusik and prusik minding pulley is likely how I'd do it and I realize that's a standard and common way to accomplish a progress capture, but the Petzl rigging diagrams remain incorrect. Plus, in a cave environment, which we're not in, prusiks may not hold well once goo and water enter the picture.

I just want to give a heads up about the Petzl diagrams so someone wouldn't rig up one of these things and wind up in a big problem.

What edition of Life on a Line do you have, Ron? I only have the 2003 version.

In looking at that version LoaL, Merchant clearly states that rigging the ascender in a compression set-up is preferable for using the Fixie pulley (p.104), although expresses similar concerns as you for swing-cheek pulleys (as you've shown in your last photo - in fact this is his preferred technique for swing-cheek pulleys). Interesting difference if you have the newer edition.

For another reference, Alpine Caving Techniques (2003, from the 2000 French edition) by Marbach and Tourte shows the same sort of set-up as shown in the Petzl documentation.

Also, I think you'll see that the ascender does not rotate as much if you clip the rope in the channel - in your photos the rope is pushed into the cam by the carabiner in the upper holes of the ascender.

A rogue climber (Pat) is visiting currently. In an attempt to shift the public's perception of how Rogues treat doors, we have put our efforts into making this refrigerator door more functional. Here you can seem me using one of these haul systems to position the door:

I don't know what edition I have, I'll check it, but I've only had my edition of LOAL for about 18 months, so it's likely it's the latest edition.

If I do have his latest edition, obviously subsequent experiences with the compression configuration has changed his opinion completely.

Yep, I should have the rope captured in the channel with the biner and that would help in situations where the pulley remains straight and in line with the rope. But still as Dr. Merchant emphatically states, the ascender can travel around the biner, creating some very bad situations, one of which is gate loading.

At best we'd have an ascender in compression, which I don't think in and of itself would be a bad thing depending on the specific application, but we also have a biner in compression and the ascender is resting on the curve of the biner. No doubt the configuration could work, but it could also produce some problems that are difficult to resolve, not to mention undesireable.

Looks less than optimal to me. Almost to the point of being, well, wrong.

I don't think it is a mistake though. Seems like they are pretty aware of the way it is shown.

I bet you Dr. Karl Prusik wouldn't like it either.

I don't think it's a mistake either - would you recommend or use it in a life-support role?

I believe this is the edition I read recently, and I kind of thought the same thing. He seemed to favor the compression technique and even described it's use with the Petzl rescue pulley.

I was sceptical, so a friend and I set up a few different combinations to see how they reacted, or if they even worked at all.

All systems were set up as progress capture on a horizontal 3:1 "Z rig" with a Petzl Rescue, heightec Pulsar, and DMM untra O biners.

Trailing clamps seem to be pretty well tested, so we started with the "infamous" compression setup. Unsuported


This setup fed rope well during the pull stroke and would hold the load fairly predictably, although the whole thing felt somewhat dicey as the clamp would creep under load and was free to move. While it caught progress, when slightly twisted with a hand it didn't take much effort with to capsize the system.



Once this happened I was no longer able to haul or relese the load properly. The system jammed up and wasn't able to be fixed until weight was taken off it.



Next we added a biner to the existing system to keep in in line and hopefully keep it from rotating. The results were encouraging.



Adding the second biner seemed to greatly improve how well the system functioned. While I was able to twist the system with my hands, the effects were much less than the unsuported system. It took a lot more effort and the system reset properly on the next stroke.



The second support biner seems to position the compression biner so it can't fully rotate.



This system turned out to be quite surprising. While I was able to induce a malfuncion by twisting with my hands, as of yet we weren't able to duplicate that with use, even rough use.

With these particular comonents, in this particular configuration and orientation it seems to be a fairly well-behaved system, though I'd be very interested to hear what the manufacturers of this stuff have to say about using equipment in this manner.


200# test



The big question still remains........

Going by this pic and info on the web:
http://www.lifeonaline.com/

I have the second edition, and that would be where I got his quote:

"…we come to the infamous “Fixed side pulley method” promoted by Petzl (but many others produce ‘tribute’ models to the Fixe pulley these days). Here the pulley’s fixed sides are put to advantage by crossing two karabiners – one for the anchor and one for the rope clamp. Now that’s fine so far, but what many people then do is put the rope clamp in compression (it’s in the product instructions, which doesn’t help!).

The explanation is that the karabiner connecting to the rope clamp sits astride the body of the pulley and so can’t rotate, and that’s true to a limited extent. What can still happen, and does with a$$-quaking regularity, is the rope clamp migrates around the karabiner instead, lifting it up, twisting it round and ruining your day. Not only is this a gate-loading problem it can get so rammed up against the pulley that you can’t shift it. It’s just as easy to put the rope clamp in tension (photo to the right), and use the same preventative methods we’ve talked about above."

he must have had a change of mind from one edition to the next if the above quote isn't in your edition.