Hose instead of manifold?

[Wet 'n Curious]

This may be a "regulator" question but...

In lieu of using a manifold can you tie two tanks together through a standard 1st stage? I was thinking that by hooking a HP hose from a HP port on one of the 1st stages to an HP port on a second 1st stage, the pressure between the tanks should equal out between the two HP chambers and the hose. The primary would be hooked up to one of the 1st stage LPs as usual.

Am I missing something? Like sanity? or some pressure piston that won't let air flow in to an HP port - only out?

Why do this??? For resort shore diving. Doubles with a manifold can't really be used. Ultimate Products makes a decent bracket for two tanks that can be used with two separate setups, but I dreamed up the hose idea.

Thoughts???

[Scubaroo]

What happens if you have a first stage failure? You can't isolate the busted reg, and you've lost the redundancy of independant doubles. No benefit over diving single tank single reg, except that you've doubled the chances of a regulator failure by having two, and added two extra failure points (HP connections between the two regs). Not sure about it even being possible in the first place, but the above considerations should make it a moot point. Is the perceived benefit of breathing the two tanks down at the same rate worth the complexity and risk?

[canuckdiver]

there is available a "cheater bar" setup that allows you to connect two rental tanks together, using one first stage. Kind of like a non-isolation manifold.
Dacor still makes one I believe
Not commenting on the safty concerns of this setup, as there is a lot of opinions, and in the end you make you own decisions.
;)

[SPEEDSTER]

In other words, either dive them as independent doubles or manifolded doubles with isolator valve. I don't think it would work anyways, and if it did, I'd bet it would ruin the reg's pretty quickly.

Mike

[Wet 'n Curious]

Thanks for the reality check. I had already come to that conclusion. I figured an added pony bottle would have to substitute for the failure possiblity. I just want a bit more time when we are in the 130' ranges. The air disappears all too fast. Additionally, my computer calculates based on actual consumption and using the bottles separately allows it to only be hooked up to one of them.

[Wet 'n Curious]

http://www.technodivers.com/

FYI after poking around based on canucks idea - these guys have a non-isolated way to combine. Still has pretty much the same number of failure points though.

[Walter]

The HP port will not deliver enough air. I do not recommend the set up you were considering, but a regulator's HP port would be an impossible option.

I agree with others that you should dive them independently or use a manifold. Some manifolds have an isolation valve, others do not. IMHO, there is little difference between the two manifolds.

[canuckdiver]

That technodivers setup isn't quite what I was referring to.
Dacor used to sell one that had a ridgid manifold in the middle with an outlet, and a yoke on each end.

[Scubaroo]

Here's a (dodgey) picture of the type of crossover canuckdiver referred to:

http://www.barracudadive-colo.com/images/xover.jpg

Often see them used on eBay.

[canuckdiver]

that's the one!

was *pretty sure* I wasn't losing my mind there ;)

[Scubaroo]

Scubaroo once bubbled...
Often see them used on eBay. Honestly!

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=1300&item=1987774338

[cclark]

Just joined this board, and am scanning it for threads of interest..

I've been thinking about this for a while. I think the way to go is with 2 first stages, each with its own 2nd stage (eq to main and octopus), then hoses with an valve to allow interconnection between the "LP" ports of the second stages. Simple, and no special fittings necessary since we're dealing with standard shop air pressures.

I'll be configuring this setup in a week or two, and will report.

Yrs,
Chris

[lucid]

The things people will do to save a buck.
:rolleyes:

[O-ring]

They market it as a traveling manifold for tech divers that are on vacation and don't have their own tanks with them. I can't remember who makes it or what it is called, but it is in the print catalog in the valves section.

[Bob3]

The crossover manifolds that were of a solid design (as in the 2 above pictures) had some failure issues from getting tweaked too many times, the brazed joint would come apart with "entertaining" results.
The old style US Divers had a pigtail that was more amenable to abuse.