GUE and Sidemount position ?

[tbone1004]

@Dan_P in backmounted tanks you have a HP manifold. justification is to have access to breathing gas out of both cylinders in event of a regulator failure.
With UTD's low pressure manifold you do not gain that advantage and as such it is not warranted. If the first stage fails, then the gas in that cylinder is lost, no way around that

 

[JohnnyC]

This looks like a GUE statement on sidemount:

View attachment 425729

Fake news!!!! A real GUE would never have a computer!

 

[Dan_P]

in backmounted tanks you have a HP manifold. justification is to have access to breathing gas out of both cylinders in event of a regulator failure.
With UTD's low pressure manifold you do not gain that advantage and as such it is not warranted. If the first stage fails, then the gas in that cylinder is lost, no way around that

The solution in this logic would be to manifold on the HP side.
Regardless of solution, HP or LP, the motivation to manifold in backmount, should be similarly valid in sidemount, surely?

I gather that some divers don't believe in manifolding backmounted tanks either, in which case I'd then understand why those divers would unequivocally prefer indies in sidemount, too.
I'm on about when there's a difference in view, depending on whether the tanks are backmounted or sidemounted.

On another note, yes, UTD's Z-system is manifolded on the LP side. I'd like to expand on the logic behind that choice.
One reason is that a LP-connection can be swapped, whereas it's more difficult (I dare say, impossible) to connect a tank against a system pressurized to 200 bar.
The benefit being ability to swap a new gas or tank onto the whole system, ensuring a consistency across all environments 100% of the dive, regardless how many tanks are needed.

As you say, there is a trade-off: if I lose a 1.-stage, the gas is potentially unaccessible - however, let's consider the scenarios to get a real sense of what that actually means:

Single-tank - literally no difference from single tank backmount. If a failure occurs on the 1.-stage, I can enter gasshare and then fix the problem or end the dive.

Double-tank - on NDL dives that require more gas, it might be logistically sensible to bring a second tank, of course. The team's rock bottom gas reserve covers two divers, so even if I'm completely OOG, I have a solution in place, but: even if I didn't, for this scenario to become problematic, I'd have to choose draining one tank to below 35 bar while I'm still on the bottom and then lose the other.
In reality, a non-issue in this scenario.

3+ tanks - if I need 3 or more tanks, I'm doing a technical dive. In that case, apart from my team, I myself still have a redundancy on 1.-stages: I never have more than 2 of my 1.-stages plugged in.
It is easy to swap one over if I'm even bothered to, or need to. That's without taking into account that I have a team around me, too.
If failing 1.-stages and subsequent gas availability in an autonomous or solo diver is the concern, that logic would dictate it's more concerning to have only 1 available 1.-stage to 1 deco tank, as is the case in manifolded backmount doubles with a single deco tank. If that 1.-stage goes, I can't rotate over my other ones.

Further, if I have a manifold failure, having the manifold on the LP side means I don't lose all my gas. I can revert to a team mate for donation and rotate all my gas to his/her system, or - in lieu with a more autonomous path, carry a spare 2.-stage, if I so choose.

The logic behind chosing the LP side to manifold, is that it gives the option of scalability, which doesn't hold true with a HP manifold solution, all without compromising on actual redundancy - rather actually increasing it.

However, I'm more on about the general notion of manifolding, rather than any one specific system/organisation. My question is, if it makes sense to manifold tanks, one would surely be interested in manifolding them regardless of the positioning of the tanks (somehow, whether HP or LP)?

 

[Doby45]

The solution in this logic would be to manifold on the HP side.

Even if you "manifold" off the HP port, when you shut the valve off you lose access to the gas in that tank.

 

[Dan_P]

Even if you "manifold" off the HP port, when you shut the valve off you lose access to the gas in that tank.

I don't mean HP manifold off the first stage, if accessing "all" bottom gas from one 1.-stage is the determining factor - rather off the valve (for instance, lola with flexible hoses, or any other solution of similar nature).

In either case, though (off valve or off 1.-stage), connecting a new tank would be unfeasible or impossible.

My point is, relevant to diving scenarios, it's not a necessary feature, and it has downsides.
It's not necessary unless I'm dismissing rock bottom gas planning and/or team diving principles.
And it comes with the risk of losing all gas if there is a leak on the HP (valve side) connection, same as in backmounted doubles.

In summary, the downsides to individual tanks is constant across the positioning of the tanks, surely.
So where lies the issue in manifolding sidemount tanks (somehow) compared to manifolding backmounted tanks?

 

[MichaelMc]

Should we move the manifold stuff to a new thread? It is not about GUE position on side mount, and could get long.

 

[Dave Bevan]

Should we move the manifold stuff to a new thread? It is not about GUE position on side mount, and could get long.

I think this is a great idea.

 

[Dan_P]

Should we move the manifold stuff to a new thread? It is not about GUE position on side mount, and could get long.

In fairness, the discussion is on the OPs interest as to whether (extrapolating "how" and "if") GUE might incorporate a sidemount solution.

I second that this shouldn't be about tooting for any one solution, nor bashing any - but implementation is hardly irrelevant to the question at hand. That's all there's to it IMHO.