@Dan_P you can't talk about how a low pressure manifold system is superior to a high pressure or lack of manifold while decked out in UTD gear, posting from an official UTD youtube channel and not have everyone go straight to the only low pressure manifold system on the market. It is about the Z-system, whether you think it is or it isn't, it is the only option out there and you happen to teach for the only agency that uses or promotes it.
The video isn't
at all about superiority of
any one approach, it's about manifolds in general, and it speaks about a vast number of things but it's certainly not centered around any specific configuration. I never even mentioned the Z-system in the video, and I'm particularly sensitive about mentioning that it's my personal choice and
why.
I don't think this is a very fair point to criticize, to be honest.
Of the solutions mentioned in this thread (indies backmount, BCD with increasingly more massive tanks with whichever impact to bouyancy one might imagine), I think Z System is by far the less controversial, anyway.
Swapping tanks should never be a planned procedure with anything other than al80's, and those tanks are not practical for most true technical diving.
Al80's work very, very well for technical diving - heck, almost everyone uses them for deco- or stage tanks anyway?
I'm not sure I undertand what you mean correctly with this argument..?
Low pressure manifolds are a great system in theory, but the practical applications of them just don't really make sense because by your own logic, the probability vs consequence of failure doesn't balance out to warrant the extensive added expense of that system nor the annoyance of having to open and close valves on a regular basis.
You're weighing up pro´s and con´s against cost in dollars?
Fine, but you're then stuck with your sidemount rig, for your logic to hold true.
You then have to use that same rig for open water-, tech-, team-, oceanic boat diving, ice diving, the works.
Okay, that's possible, but that's a heck of a cheapscape solution to tinker about with indies on an icy oceanic dive because of the cost of a manifold and a couple of gas connectors.
In the grand scheme of things, it would have been a heck of a lot cheaper for me, personally, to start out with Z-system from Day 1. That's not even taking into account all the jacket-style BCD, split-fins, computer and backup computer, etc. -
purely looking at rig.
Use of others stage bottles is certainly not something you should ever do, however it does happen in rare circumstances, and there are individuals that would not be with us if those tanks did not have second stages on them. The KUR has second stages on all of their stage bottles despite having what is essentially a LP manifold attached to their rebreather because if they hadn't, at least one of their team members would have been dead because of it...
We could go into a lengthy discussion about rebreathers, but I'll keep it to being able to use the rebreather "base" as an open cirquit bailout platform, hence not requiring to add an extra LP hose with an extra reg, to it.
Those individuals you speak of, if they did get saved because someone had a spare reg on their staged tanks and everything worked out well, bene - but the QC was hardly the cause of their problems to begin with, and so the QC/reg shouldn't be the solution to them.
What if the "snatching" of those staged tanks actually ended up getting someone (else) killed?
The problem couldn't have been whether or not there was an extra reg on those tanks. It'll have been why the diver(s) who nicked them, weren't self-sufficient within their team.
I acknowledge that it'll might come off insensitive to say so, but all the same.
Surprised that one thing you hadn't mentioned as a con of that system is salt water ingress into the system. QC6 does not have a lot of water come in when you plug it in, but it does have some, and when diving in salt or any sort of contaminated water, you are blowing that all through the hoses/manifold/adapters/regulators and it does have a very real impact on how frequently you have to service regulators. I have seen the inside of some second stages from a guy that uses the z-system in salt water and it was UGLY. This was after the manufacturers recommended interval not an extended service interval. It is a concern that all CCR divers have and is part of why they try to avoid using quick connects in the water unless there is an emergency. Having it as SoP and required for any dive with more than 2 tanks makes that water ingress a very real thing you have to worry about.
I don't think it's a problem, no. I have serviced plenty gear from QC and non-QC systems, and don't really see much of a difference. Most of what I've heard from the RB80-sphere was that the salt ingress was never really a big issue there either.
I've seen plenty of ugly insides of regs within service interval without QCs and plenty with QCs that looked stellar.
I get that you'd like for the Z system to make sense but struggle to in light of your personal diving. That's fine, I don't have a problem with that.
From this side of the table, it's looking like a bang tidy solution, that's all.