Z-system advantages

[Dan_P]

I don't see that as an advantage over a manifolded twinset though... I prefer having gas to breathe over having gas to inflate my wing.

Personal preference is cricket. I have nothing to put on that, at all.

When it comes to the gas logistics of the Z-system, though, I'd note the following:
Going through the scenarios, you'll never be OOG from any failure because you've selected Z system over backmounted doubles.

On single tank, you're in exactly the same situation whether you're on Z system or backmount.

On doubles, you have enough gas to get home in either case.
Even if you were in the worst possible situation (40m end of dive, or thirds at maximum penetration), you'd still be in good shape if a 1.-stage goes.
The only way one's not, is if one 1) can't manage gear and 2) can't manage gas and 3) can't manage the team. In that case, yes, one might be better off on backmounted doubles (talk about an equipment solution to a skills problem).

With 3+ tanks, I always have redundancies, and I'm significantly better off with the Z system than backmounted doubles when I do staged/deco dives, for a number of reasons.

I think the ability to easily access gas from two dedicated bottles in the event of a 1.-stage failure (which is a feature I don't need), comes at the expense of using that rig for anything but those two tanks.
I.e. I'd be sacrificing my scalability/consistency for a solution that really doesn't do anything for me but be more forgiving if I have 3 major failures that are directly related to lack of skill plus a fourth that has to be a specific one.

I really think gas logistics is a non-argument, to be honest. That being said, if anyone wants to use any system at all, that's fine - I'm just saying there's nothing to put on Z system in terms of gas logistics.

If there is any scenario that actually validifies choosing backmounted doubles over Z system for gas logistical reasons, I'd be most interested in hearing which it might be.

 

[DevonDiver]

Logistically, I have experienced a range of benefits to the Z system when travelling by both sea, air and land, across regions.

I'm interested to see if there's a single non-UTD trained diver or instructor that shares your perspective. I've never once met a diver outside of UTD that lauded the Z-system.

The only people I have ever seen promoting the Z-System are UTD instructors. Go figure... it's the only system you're allowed to teach/dive in... and it's a system manufactured and sold by your agency. That constitutes a very vested interest.

 

[RainPilot]

it's the only system you're allowed to teach/dive in...

Not true. I dive and teach independent sidemount for RAID and Z for UTD. There is no proscription on my diving from UTD.

FWIW I prefer the Z for my personal diving. All these strange systems people have come up with in order to facilitate gas donation. Every hose length known to man in every combination.

Andy, have you actually dived the manifold before? I'm genuinely curious.

Oh and it's not koolaid in my case. There is a laundry list of things I disagree with UTD on. If I left the agency tomorrow, the two things I would DEFINITELY keep are the Z and rock bottom gas planning.

 

[Dan_P]

The only people I have ever seen promoting the Z-System are UTD instructors. Go figure... it's the only system you're allowed to teach/dive in... and it's a system manufactured and sold by your agency. That constitutes a very vested interest.

The system you're not allowed to teach in, your competition, you're bashing vigorously - talking about interests.

The point being that a diligent technical diver educates themselves from the latest, and most respected sources, not just gulping down a single ideology or agency-imposed dogma.

The words seem nice enough, but what you're really doing, is calling a rig an "ideology or agency-imposed dogma" because you don't agree with it.

It really comes across as though you can't imagine anyone disagreeing with you on this for any other reason than them being a zealot...
I'm not saying the Z system is the universal truth to the sidemount question.
I'm saying I see benefits to that configuration - and I'm not bashing divers who opt for other configurations.

As you speak of dogma, you're actively teaching and seemingly advocating deep air.
Referencing "latest, and most respected sources", it really doesn't get an aweful lot more dogmatic than deep air.
It's just a worn page in some book from when nitrox and trimix were "voodoo".

GUE took onboard and adopted the findings of more contemporary studies into gas density issues. As have I.

What has GUE got to do with this?

And which studies are you talking about?
I say 5g/L gas density is a reasonable limit, equivalent to 30m on air. That's based on scientific study.
You teach close to 8g/L. Where did that come from?

The reason I mention your practice is because 1) you're slantering mine on baseless personal views, and 2) because the agency you teach for (by extention, and more relevant, you) prescribe diving to 50m on air (look in your standards and tell me that's not a doctrinary demand rather than guideline), which is well in excess of reasonable, unless you're using the phrases "more contemporary studies" and "flannel" interchangeably.

I don't believe that technical diving is exemplified by regurgitating what agencies disseminate. Perhaps so at a rudimentary level of novice tech diving, but experienced technical divers should have the motivation and inclination to do their own research and adopt their own value systems.

You're taking digs at divers for using a specific configuration, but if you run the 50m course you advertise, you're required to do it on air, to 44m-50m depth.
You're either "regurgitating what agencies disseminate", or breaking their standards.

Reversely, if I want to dive indies, there's noone stopping me - I'm free to pursue training in that configuration as much as I like - UTD just don't offer indies training is all.

Dan, you seem preoccupied with PADI. It's currently my teaching agency of choice; for a number of reasons. I've had 3 teaching agencies before that. And there'll be a new agency soon. What's most significant is that my diving beliefs and teaching practices haven't changed between agencies. This is technical diving, not open water courses...

I'm not preoccupied with that organization - rather, I'm taking to retort in conversation with a person who bashes left and right the way I dive, and effectively calls me a "spoonfed drone".
An organization is not at the core of what I'm saying - what you practice compared to what you preach, is.

Do I use air for 40-50m dives?
Yes, I do - when the dive warrants it. And Dan.. I've done more 40-50 air decompression dives than you've done dive in total.. and then some. I've also done dives, long ago, far beyond 50m using air...

Take note: this is quintessential Turkey's Logic.

Dives don't flipping well warrant hypercapnia - just because you can bring your learning drivers to a closed cirquit and pull off a few laps with them blind drunk behind the wheel doesn't mean drunk driving and having survived makes you the big banana.
And it doesn't make your learning drivers capable of pulling it off on the motorway, either.

There's a vast difference between saying "what I was told is..." and saying "what I believe is..."

If you don't really believe in what you're being told, I get why you'd come out with a statement like that.

 

[decompression]

I'll toss in 2 PSI, I teach for 3 Agencies and I would say 2 of them are definitely benefiting from me being trained in the third. I'm able to offer the best "fit" in Sidemount to whom ever comes through my door. And it's unfortunate that an entire agency is condemned for a few debatable points versus the overwhelming benefit to the industry and environment by producing highly skilled, knowledgable and passionate divers. This is done by high agency standards and not just a one-off instructor or two that have a desire for the same result.

 

[DevonDiver]

The system you're not allowed to teach in, your competition,...you're actively teaching and seemingly advocating deep air....You teach close to 8g/L.......The reason I mention your practice is because ....

You do realize these are all spurious assumptions... and that you actually have NO IDEA what, or how, I teach. Right?

Is this the propaganda that UTD teaches you?

The words seem nice enough, but what you're really doing, is calling a rig an "ideology or agency-imposed dogma" because you don't agree with it.

Actually, all I did was draw attention to the state of Z-system across the broader sidemount community... it's lack of adoption beyond the UTD fringe and the general negative impression that it receives across social media from the spectrum of non-UTD divers...

I furthermore drew attention, through deductive reasoning, that it's popularity ONLY within UTD seems most logically due to it solving a dogmatic, not practical problem.

Ergo.... nobody outside UTD... have ever seen a practical problem with non-manifolded sidemount. Therefore, the problem isn't practical if nobody else experiences it.... it's a problem rooted in adherence to a rigid doctrine and belief system.

It really comes across as though you can't imagine anyone disagreeing with you on this for any other reason than them being a zealot...

You DO seem to be responding very defensively and making a mass of assumptions... in a rush to deny critique of the rig. And there's shades of personal attack... which isn't very kind... and tends to indicate you're a little emotionally effected to have anyone 'dare' to question your personal belief system. Just saying... and no insult intended... that a moment of self-reflection might aid you ability to perceive what's been said... instead of resorting to a typically defensive knee-jerk reaction.

 

[DevonDiver]

Not true. I dive and teach independent sidemount for RAID and Z for UTD. There is no proscription on my diving from UTD.

Apologies. To clarify.. "The only thing you're allowed to dive with inside a UTD team, or on UTD training".

I acknowledge that UTD, like any agency, has no power to police or sanction a divers' decisions beyond the training structure, or formal agency diving teams etc...

Out of interest... why don't you use Z-System for your RAID courses also? I'm in the process of familiarizing myself with their standards and procedures at this time - but not read into the sidemount course standards yet. Do they specifically specify independent cylinders?

 

[RainPilot]

Out of interest... why don't you use Z-System for your RAID courses also? I'm in the process of familiarizing myself with their standards and procedures at this time - but not read into the sidemount course standards yet. Do they specifically specify independent cylinders?

Please understand that I am speaking only for myself here, and my particular circumstances.

Some background:

My wife started diving in 2004 when I began to seriously dive again. It was a pastime we could both do together, and since I was deployed around 40-45 weeks a year, it was vital that we spend the time we had together, together. She enjoys diving but has never been particularly passionate about it and has no intention of ever becoming a "serious" diver. She finished her Rescue course and thats where it ended.

She has had back issues for a really long time and we had to get creative with finding equipment configs that wouldn't give her problems with the shore entries and thick wetsuits we needed in Cape Town waters. Eventually we settled on a 7 liter 300 bar cylinder since, with her air consumption, that was good for a 50 minute dive easily, by which time we were cold anyway.

Fast forward a couple of years and we are out here diving warm waters for longer times, and access to 300 bar fills is more challenging. She used AL80 back mount a couple of times but getting up the ladders etc was putting a lot of strain on her back, to the extent that she was laid up in bed a couple of times and told me she was done with diving.

At around this time I was changing over to RAID for my CCR diving and met the UTD folks for the region. I had been looking for training to be a better diver and found that the skills for UTD (like GUE) are VERY high, it was the first time I had felt challenged in my diving for a LOOOONG time.

This was when SM first came to my attention as an OW option. I had previously discarded it for my wife because she had no desire to relearn all the procedures and skills she had been using over the years. When I saw the Recreational Z-system I realized that here was an option for her. It would allow her to dive with one tank and still keep the same donation procedures etc etc that she was familiar with, and if she dived with 2 smaller tanks there would still be no change.

I encouraged her to do the UTD SM course with me, I chose to use the iso manifold since I was planning to go tech later and she used a simple distribution block. When she started she couldn't believe how simple the transition was and my dive buddy was back!

After around 100 or so dives on the Z, RAID released their SM courses and I went and did the PADI Tec SM course in order to gain some experience in independent SM. I felt a great deal of frustration in the learning curve I needed to donate gas quickly, pulling on a bungeed reg before I realized which one i was breathing off etc. The "my mouth to your mouth, always" that I had carried from BM to Z-SM was so natural that it took me a while to get used to it.

After the course, I did another 40 or so dives on independent SM in order to build the muscle memory I needed but it still isn't as fluid as the Z for me.

To your question, if I got very creative with the interpretation of the standards I could teach the manifold for RAID. However, I choose not to for a simple reason. My students will go forth into the world and dive in a variety of places and quite possibly, end up with cave training or diving with yourself (Andy) later. If they arrive with 200 SM dives but all on the Z, they will be at a serious disadvantage going into a course where they are prescribed independent SM.

What I do now is introduce them to the concept, and where possible I add in an OW dive where I let them use my rig so that they are aware of the existence and pros and cons of the system. A nice thing is that the nature of the system makes it super easy to use, tank handling remains the same, hose tidying before exit is a 2 second task since the second stages all stay on the harness and OOG etc is a doddle. So far, in terms of ease of use, all my students have had a BIG preference for the Z.

Since I am not an overhead diver (yet), the discussions around failure points and entanglements etc are not applicable to me or my diving. For slinging on as many tanks as you need and going OW diving, I have found nothing that compares for ease of use.

 

[tbone1004]

The system you're not allowed to teach in, your competition, you're bashing vigorously - talking about interests.

I am unaware of an agency that teaches sidemount outside of ISE that would not allow you to use the Z-system when teaching sidemount btw. Plenty of instructors that may not allow it for their students, but I'm not aware of any that wouldn't allow the Z-system to be used.

I'm also not entirely sure why @DevonDiver 's choice to use deep air is relevant to this discussion, but you do realize that where he lives, helium is basically not attainable yes? You can't just go out and choose to do a 100m OC dive on helium in the Phillipines like you can in Europe or the US so they have to dive deep air if they want to go down that deep

 

[DevonDiver]

I'm also not entirely sure why @DevonDiver 's choice to use deep air is relevant to this discussion,..

I'm mystified how/why I'm suddenly a deep air diver at all? LOL

I'm running a 45m normoxic course (Tec45tmx) in a couple of weeks.....which, apparently, is an impossibility if you're to believe the UTD propaganda.. LOL

Trimix is readily available here in Subic, albeit far more expensive than in the USA.

Long gone are the days of 50-90m deep air... I haven't seen that sort of diving done anywhere since even before agencies like UTD have existed...