UTD Z-side mount with isolatable manifold

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As demonstrated to me by AG at UTD HQ San Diego before my Bikini/Truk Trips a few months ago...

Come on now! Do you always have to reference your Truk trips and ww2 wrecks? Enough is enough already.
 
...you have to open BOTH tank valves THEN isolate, and then expeditiously go through the 9 point failure drill like you would and as you learned in conventional backmount (taking into account the QC6 connections as well).

I chose to retain the original Distribution Block -again because I didn't like that Isofold Valve Wheel poking my back & neck- and more familiarization with the original solution of plugging in the back-up QC regulator (or going to a redundant tank reg) after disconnecting both male QC6 tank whips. I'd rather automatically disconnect and by-pass the Distribution Block, plug in the QC back-up and abort the dive rather than go through the 9 point failures drill with an installed Z-Isofold manifold.

I took the B#$%ni/T#$k references out from the above quote! lol

Anyway, that procedure doesn't seem right. I figured the first thing I would do is isolate the back manifold, that may eliminate the leak immediately if it happens the be on the side with the tank that was closed (which would be as fast as conventional), if that doesn't eliminate the leak I would turn on the closed tank and then close the open tank (that's where more gas than I would care to lose would occur). I would then immediately abort the dive (I don't know why you would take time to screw around with 'failure drills'). If I did not have enough gas in my only available tank then I guess I would have to fumble with the QC back-up reg on my way up.

Can you elaborate more on the 9 point failure drill for this system?
 
(I'm gearing up and going on a road trip down south to San Diego to dive HMCS Yukon wreck all day Sat 31Aug, so I'll leave y'all with this for now)

A very cursory overview of the 9 Failures Heuristic Model:

For conventional backmount manifolded doubles, the two main objectives are: Determine which side the failure/leak/malfunction is actually occurring, and whether it is due to a post failure or a manifold failure.

The 9 Failures are inductively simplified as follows:

Right Post Failures: Either Fixable (#1) or Non-Fixable (#2).
Right Side Failure in general vicinity of Manifold Crossover to Isolator Knob (#3).

Left Post Failures: Either Fixable (#4) or Non-Fixable (#5)
Left Side Failure in general vicinity of Manifold Crossover to Isolator Knob (#6).

Mistakenly perceiving the Failure on the Right Side, when it's really on the Left (#7).
Mistakenly perceiving the Failure on the Left Side, when it's really on the Right (#8).

Manifold Valve broken/leaking or absolutely have no idea where the Failure is . . .(#9)

Similarly for Z-sidemount with the Isofold:

Right Regulator Failures: Either Fixable (#1) or Non-Fixable (#2).
Right Side Failure in general vicinity of Hose connection to Isofold (#3).

Left Regulator Failures: Either Fixable (#4) or Non-Fixable (#5).
Left Side Failure in general vicinity of Hose connection to Isofold (#6).

Right Tank Valve Failure (#7) or Left Tank Valve Failure (#8);
and Z-system gas delivery interruption (#9).

QC6 connection/disconnection scenarios & options are also part of the problem solving outline above for Z-sidemount with Isofold. To recap for Z-Isofold: If you hear bubbles, open both tank valves and isolate; if no bubbles but you have breathing gas interruption -then open both tank valves but do not isolate. In each case go through your 9 Failure heuristics and flow checks once the problem is solved. (Also you're supposed to be with teammates as well --ask for their help or long hose donation as needed).
 
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That initially sounded more complicated to me than it actually is. Most of the steps would be answered right from the start, the rest would be answered during the isolation process.
 
the original solution of plugging in the back-up QC regulator (or going to a redundant tank reg)

Hold on, so your procedure for fixing problems is converting it into a standard sidemount system? So....why not just START with independent tanks if that's your final solution?

Also, according to your 9 Failure Heuristic Model...independent sidemount would have 6 failure points (all besides those relating to isofold). Right?
 
Hold on, so your procedure for fixing problems is converting it into a standard sidemount system? So....why not just START with independent tanks if that's your final solution?
My prerogative -I dive both horgarthian/DIR longhouse backmount & sidemount doubles on the same overseas trips often in between dives . . . Z-system as elaborated fully above works for me.
Also, according to your 9 Failure Heuristic Model...independent sidemount would have 6 failure points (all besides those relating to isofold). Right?
Enumerate & explicate it for conventional sidemount yourself.
 
What sort of principled philosophy favors increased failure points and more complex emergency responses, in order to achieve nothing more than alleviating the need to properly communication/train a gas donation in a precisely identical manner across different configurations?

Trying to view this from as many perspectives as I can, and with maximum empathy, but it just doesn't add up..
 
What sort of principled philosophy favors increased failure points and more complex emergency responses, in order to achieve nothing more than alleviating the need to properly communication/train a gas donation in a precisely identical manner across different configurations?

Trying to view this from as many perspectives as I can, and with maximum empathy, but it just doesn't add up..
Very well Andy . . .you stick with what you're trained with (and what you've purchased as well!:wink:).

MSorpa (Mike) in a PM essentially pointed out that my present Z-system configuration "evolution" is now conventional sidemount with an attached Distribution Block feature. Perhaps I'll make the transformation to the less complex, more simpler kit someday. . .

[Had four backmount double AL11L tank air dives on the HMCS Yukon yesterday Sat, off Mission Beach San Diego --not wrecks in tropical Truk, Bikini or Vanuatu!-- all in zero to 2 meter visibility at best; at a bottom depth ave of 21m and time ranges of 30 to 50 minutes in 12 deg C water temperature (24C air temp) --so nice to be home in SoCal temperate waters:wink:]
 
MSorpa (Mike) in a PM essentially pointed out that my present Z-system configuration "evolution" is now conventional sidemount with an attached Distribution Block feature. Perhaps I'll make the transformation to the less complex, more simpler kit someday. . .

To me, Z-system is a simple sidemount system, that breaks multiple fundamental tech principles in an effort to work like back-mount. That isn't a dive determined necessity (other solutions exist) - it is an agency dogma mandated necessity. It has no need to work like back-mount, it isn't back-mount. It is workable... but it isn't optimal - not if the diver respects the principles of minimal failure points and K.I.S.S in respect to configuration and procedures.

I just don't see the benefit of compromising a majority of important principles in order to effect one single principle. Especially when that principle ('from the mouth' donation) is of much less critical nature.
 
https://www.shearwater.com/products/peregrine/

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