Petzl has updated the Zigzag for 2014. It has been designed to work in DdRT systems, only. It seems that it might be okay to use it with a RW, because the RW is providing friction by creating a bend in the line, similar to the additional friction in a DdRT system which is provided by installing the line over a limb. However, you would have to understand that this is a novel experimental use of the equipment, not endorsed by the manufacturer. That means you have to go into it with eyes wide open, and take full responsibility for using the equipment this way. Make sure to have a backup plan in place, and use extreme caution! By the way, it sounds like an expensive solution.
Petzl has some troubles with the Zigzag for sure. But nothing really dangerous as long as you check often, like you should with any other gear. It has good sides, and bad sides too, but i don't know one climbing gear that has only good sides...
I'm not a Petzl fan, i'm not a Zigzag fan, and i'm kind of paranoid when it comes to safety, but you may catch me using the Zig with a lot of joy.
Anyway. Petzl clearly asked to NOT use the zigzag in SRT like with a Wrench. Funny thing is that the Zigzag has been shown by some Petzl demonstrators in SRT with a Wrench above it...
I wont say it's not safe, but even if some demonstrators were playing the "do what i say and not what i do" card i would stick to Petzl's manual and respect their advice.
What is SRT? These days, this is a very interesting topic. Specifically, in the case of the Rope Wrench, we're talking about a revolutionary piece of equipment. The Wrench itself puts a bend in the rope creating friction, so that it is possible to ascend AND descend on the hitch below it. This would not be possible with a single hitch. In a sense, the rope Wrench performs the function of the limb of the tree which your rope travels over in a DdRT system. So, theoretically, it would be possible to use the ZZ under the Wrench. There has been some discussion on this very topic on Treebuzz, and if you're interested, I think it would be worth your while to go there and check it out.
Thanks Dogwood. In France (and other european countries) legislation says that we must not only respect EN standards but also what the brand noticed about its product. I know the ZZ works fine under a RW, but as Petzl said "no use with SRT" it is no use with SRT.
One of the reasons is that if there's a failure with the RW the ZZ is on one line and that would be dangerous. I know a RW failure has really really low probability, but the ZZ being possibly dangerous in SRT configuration has an higher one, so that has to be tooked in consideration.
Other reason is the RW is not EN standardized as a stoper (and as anything else by the way) so if the ZZ fails you can't count on the RW to take you back. Maybe can you, i don't know about that and i'd be pretty curious to be aware of it by the way... but EN standards say you can't. Once again this is in my mind because i got to deal wit it, i completly get that it's an other story for you guys.
Third reason is that Petzl don't like to share with other brands so they will continue to forbid this use as long as they wont produce their own solution. Wich by the way allready exists in facts if you use ropes under 11mm : the shunt that works good as a RW. But that's only in facts, Petzl, so far as i know, didn't communicate about that use. Wich is silly IMHO, and also silly that Petzl don't bring a version of the shunt for ropes between 10 and 13mm, but that's an other story.
I saw the discussion about SRT in Treebuzz, really interesting indeed. When i say SRT here it's in the classical popular way to mean it in opposition to DdRT, wich is also SRT indeed, but talking about the ZZ it has an important meaning using it that way. Even if it's not deeply correct.
I'll use SRT.s and SRT.d, things like that, as soon as new standardized acronyms will be spread. But for now i guess it's better to use old school acronyms as long as people understand it more that way. I guess it may take a while as many of us are still confused between DdRT and DRT...
From all reports the ZK-2/Zig Zag combination works pretty well. Of course you're voiding your life warranty by climbing on an experimental rope system
I have 2 concerns about using the Zig Zag SRT with the ZK-2:
The first one is about connection point durability. The Zig Zag has two life support connections to the rope. One is the metal friction component attachment to the rope. The other is the the carabiner attachment for the static leg of the DRT system. In SRT configuration all of the life support is on the metal friction hitch attachment. The ZK-2 is strong but is not life support, the climber really has to depend on the security of the metal friction component. I'm sure it's quite strong but... Petzl intended the load to be shared between the carabiner attachment and the friction component. To be sure the ZK-2 does create a load share but if the ZK-2 or tether fails, it's all on the metal hitch. Since Petzl has still not fully resolved a recurring cracking problem in the metal hitch for DRT mode, it could be expected that the cracking problem might be amplified in SRT mode.
The second problem I'm worried about is side loading the Zig Zag against a limb. When I climb SRT with the ZK-2 and cordage hitch I sometimes end up in an unavoidable situation where I'm passing a limb either ascending or descending and the rope angle compresses the ZK-2/Tether and hitch sideways against a limb or branch. My tether is flexible enough that it handles it well. Likewise the ZK-2 bumps its way around the limb pretty well. The cordage hitch has no problem. I would be very uncomfortable subjecting a Zig Zag to this kind of intense sideloading. I could avoid sideloading the Zig Zag but that is unpractical, a climbing system needs to be robust enough to withstand this fairly common climbing situation.
I think my first concern is manageable risk. If the ZK-2 tether and attachment to the Zig Zag are configured to life support quality (as shown in Wachin's photos) then the risk is significantly reduced.
I don't see a solution to the sideloading problem.
Tree climbing knowledge and technology began a few years in Taiwan, and in my learning process, I refer to the relevant knowledge of a large number of foreign (such as books, films, photographs, etc.), which contains Andrew Joslin (AJ) at Flickr. com many tree climbing photos. AJ's event photos provided me a lot of tree climbing techniques and concepts of information.
Through books, films, photographs, my careful consideration and implementation as well as understand the implications of the pros and cons. Of course, all this is performed in conditions of security priorities.
In Taiwan, tree climbing equipment are purchased from foreign websites (high price). But the biggest problem is that the tree climbing techniques to learn and implement. Therefore, a lot of things have to be groping attempt.
I am glad that my problem could get so many suggestions and response
About ZK2 used in the SRT, I will continue to go on learning.
The thing about the zigzag is that it does and is operated the same way as a hitch, but without the versatility of a hitch
Now I haven't played with one, but it doesn't look like you can adjust the friction( someone please correct me if I'm wrong)
When I went from doubled rope to single line, the first thing I noticed is that my hitch needed some refining
Maybe the zigzag is set perfectly for it, but it took me a while to find a hitch, and cord type and size that worked well for me on the RW
Moss your point about side loading is bang on, this can also happen in doubled rope configuration, bit concerning really
What is it about the zigzag that is so appealing to you Wachins?