Petzl Zyper

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Petzl Zyper

Postby jharman2 » Jan 19, 2013 11:09 am

Is anyone using the metal shock absorber from the Petzl Zyper [1] as their center cowstail attachment? To do so requires completely destroying the Zyper and re-threading the metal piece with your own dynamic rope. I've been using this rig for a few months and really like it. It is a really dynamic system and allows on-the-fly adjustment of the cowstail lengths. Couple questions:

1. Are there any safety concerns?
2. What size rope is best? I'm using 9.4mm but I think it may be a little skinny. I'm pretty sure the 9.4mm dynamic rope I have is double rope. I'd probably feel better with single rope.

[1] http://upload.wikimedia.org/wikipedia/c ... ZyperY.jpg
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Re: Petzl Zyper

Postby Scott McCrea » Jan 19, 2013 7:38 pm

What does it look like after you destroyed it?

I'm sure Petzl would frown on you mods, but I would guess that the rope hand and diameter would play a big role in how it works. Mud is probably not something they intend to be in the equation. But, I can't see much harm in what you're doing. As long as it mostly works, the worst that would happen is it would slide against the knot and stop.
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Re: Petzl Zyper

Postby Scott McCrea » Jan 19, 2013 7:40 pm

Have you seen this? The way to shorten a regular cows tail by two-thirds?
http://caveworthy.blogspot.com/2009/05/ ... -tail.html
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Re: Petzl Zyper

Postby caver.adam » Jan 22, 2013 3:23 pm

I use a prussic on my QAS line to change the length on the fly. No modification of any metal gear. Just have to tie two additional knots.
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Re: Petzl Zyper

Postby driggs » Jan 22, 2013 3:46 pm

I wonder if you could slip a length of bicycle innertube over the metal brake portion of the Zyper to protect it from mud, while having it still remain adjustable?

According to Storrick's site, the older Petzl Zyper was in a "cowstail" configuration, but used a giant 13mm rope! Your 9.4mm rope holds a static load without slipping?
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Re: Petzl Zyper

Postby NZcaver » Jan 23, 2013 6:12 am

I have one of those old Zyper cowstails somewhere, but I never used it caving. I had thought about chopping the rope and threading a thinner 9mm-ish dynamic rope more suited to caving cowstails through the 'buckle' part, but ended up using a Kong Slyde instead. It worked pretty well and was my cowstail of choice for a few years before simplicity won out and I went back to the old tied double cowstail again.
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Re: Petzl Zyper

Postby Caver John » Jan 23, 2013 7:35 am

I love my kong Slyde!
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Re: Petzl Zyper

Postby jharman2 » Jan 23, 2013 3:59 pm

driggs wrote:I wonder if you could slip a length of bicycle innertube over the metal brake portion of the Zyper to protect it from mud, while having it still remain adjustable?

According to Storrick's site, the older Petzl Zyper was in a "cowstail" configuration, but used a giant 13mm rope! Your 9.4mm rope holds a static load without slipping?


Cool! That's almost exactly what I have "built". Mine had the 13mm cord in it too before I cut it out.

The 9.4mm holds a static load. However, I do experience some "creep" after multiple loading cycles.
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Re: Petzl Zyper

Postby Mike Hopley » Jan 29, 2013 6:08 am

With the Petzl Zyper, you would be well advised to use rope of the same diameter as the original kit. Using thinner rope could cause your cowstail to slip at low loads, which could actually increase the impact force in a fall! Your cowstails should be no easier to pull through than the original rope was.

A Kong KISA is effective as a shock absorber, across a range of rope diameters (9 to 11 mm). The recommended threading pattern varies depending on the thickness of the rope and the conditions it will be used (wet or dry).

Note that such a cowstail will not be as effective as a true Via Ferrata lanyard, because there isn't enough rope to pull through in the event of an extreme fall (like, factor 10!). Nevertheless, it is far more effective than a standard caving cowstail at reducing impact force. This makes it a practical option for, say, bolt climbing.

I've used one of these, and it worked well -- although I'm back to just rope now, like NZcaver.
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