My "new" independent doubles setup

[SubseaSports]

A bit late to the party....I stopped reading at page 6 lol
Very interesting setup. I use to do quite a bit of ID diving before switching from smaller capacity tanks to larger ones. Now mostly, large tank with a bailout.
When I did dive ID I was going to go with a gas switch block but never justified buying one. I did have and AGA that I dived in the mix as well.
Thanks for sharing.

 

[AfterDark]

A bit late to the party....I stopped reading at page 6 lol
Very interesting setup. I use to do quite a bit of ID diving before switching from smaller capacity tanks to larger ones. Now mostly, large tank with a bailout.
When I did dive ID I was going to go with a gas switch block but never justified buying one. I did have and AGA that I dived in the mix as well.
Thanks for sharing.

The setup actually outperformed expectations. The tanks stay equal to within 100 - 200 psi thru out the dive with both inline valves opened. No switching is required, both valves can stay opened. The tanks can still be isolated from each other via the inline valves if required so the redundancy is not lost, and the tanks remain independent.
The AGA had the bottom mounted valves if my memory serves me correctly. I had considered a bottom mounted setup but valve guards I could make are too heavy and a lighter one manufactured by a local shop was too expensive to justify for the use it would get., IMO.

 

[Angelo Farina]

The setup actually outperformed expectations. The tanks stay equal to within 100 - 200 psi thru out the dive with both inline valves opened. No switching is required, both valves can stay opened. The tanks can still be isolated from each other via the inline valves if required so the redundancy is not lost, and the tanks remain independent.

That is what I was expecting! Good job! Can you post a photo of the final setup?

 

[AfterDark]

That is what I was expecting! Good job! Can you post a photo of the final setup?

Thanks Angelo, the setup hasn't changed, it's still looks the same as the second picture at the beginning of this thread. I haven't used those particular tanks, yet because I use 50 cuft tanks for shore diving with IDs and that's all the diving I had the chance to do this past season.
Thanks for all your input on this thread Angelo!

 

[Joris Vd]

The only clear issue with this setup is ofcourse the bottleneck of the second stage. If that one fails there is no backup.
One interesting thing could be to use qc-adapter on the second stage and put an extra second stage in your pocket?

 

[AfterDark]

The only clear issue with this setup is ofcourse the bottleneck of the second stage. If that one fails there is no backup.
One interesting thing could be to use qc-adapter on the second stage and put an extra second stage in your pocket?

No, evidently you missed the part about the second second stage mounted on the right-hand 1st stage. The system has 2 second stages. The only issues I've encountered with this system so far are like this one, made up by SB posters.
The right hand 1stage and the primary 2nd stage would have to fail at the same time for an OOA scenario.

 

[BlueTrin]

I didn’t know that these in-line valves existed.

That’s interesting.

 

[Joris Vd]

No, evidently you missed the part about the second second stage mounted on the right-hand 1st stage. The system has 2 second stages. The only issues I've encountered with this system so far are like this one, made up by SB posters.

I misread... In the first post I was under the impression you were running two separate setup according to the pics.

You might have thought I was trying to be snarky after having to defend the setup for 24 pages, but I wasn't. I just incorrectly understood the setup. Your defensiveness is quite inspiring though. I hope to be as grumpy as you one day.

Still... a really 'intricate' way to get around a shoulder problem.

The only thing I don't really see is why you would run this over a separate doubles regulator switching setup.
I know you said earlier an instructor thought you were in distress, but lets be honest, nowadays with so many people diving sidemount or primary donate, are we really that surprised if we see a regulator switch underwater??? i'd say no tbh.

It's alot less hoses, less ****, but this looks cooler I guess?

 

[BlueTrin]

I misread... In the first post I was under the impression you were running two separate setup according to the pics.

You might have thought I was trying to be snarky after having to defend the setup for 24 pages, but I wasn't. I just incorrectly understood the setup. Your defensiveness is quite inspiring though. I hope to be as grumpy as you one day.

No offense, but surely you could reckon that it’s as valid to think that you could make the effort to read the thread before to reply. Especially if you attack his so called grumpiness.

I would not worry about reaching (one day) his “grumpiness”, you are well on your way to excel in this domain.

 

[kelemvor]

I posted this in regulators but I also wanted to post it here where some may use IDs

Single 2nd stage independent doubles

One of the "drawbacks" of independent doubles (IDs) is the regulator changes. Removing a regulator from one's mouth at 100+ feet is something that some people might advise against.
It can also create the false image that you maybe in trouble.

For example: A DM once told me post dive that when he saw me drop my regulator from my mouth @130FSW so he began moving towards me thinking I may be narc'd and in need of help. He came over to me after the switch was complete and gave me the OK sign which I returned not knowing why.
Since I started diving when divers were still doing a fair share of DIY of their own gear I guess it's ingrained me. So because I can I've rigged a configuration that eliminates the regulator switches while using my IDs and a newly serviced SP AIR 2nd stage because it is capable of being connected on either side or both sides at the same time using 2 1st stage in this case 2 retro fit and upgraded SP MK5s both with solid IPs of 135psi and I have it already.

Gear I used is the aforementioned second stage that can be connected from both the right and left, 2 on/off inline valves, 2 90 degree elbows, and 2 LP regulator hoses long enough to route under my arms; also 2 1st stages with similar IP's, and lastly 2 over pressure relief valves installed in a LP port on each 1st stage. Since only one second stage is used, a second 2nd stage is used on the right hand 1st stage in case of 2nd stage failure or for donation as an octo if used with a buddy(s). For access to both tanks an AIR type inflator can be added to give the diver a third 2nd stage option.

The left side 1st stage is connected to the left side of the 2nd stage by the elbow. The right tank is connected to the right side of the same 2nd stage the same way. The 2nd stage is necklaced and the LP hoses are routed under my arms. Tank switches are made by push/pulling the inline valves on and off instead of switching regulators.

There maybe a slight reduction in redundancy however the diver still has 2 second stages that can access either tank thru a separate 1st stage so the reduction is slight. To have trouble more than one problem with what has been a rock solid system over many years and dives has to happen in the right combination to be OOA thru equipment failure. The AIR and a 1st stage failure on the right hand tank would leave the diver no options. If a AIR inflator is part of the system on the left hand tank then that would be the last resort. If not it would be as if a single tank diver with a primary and octo reg had a 1st stage failure.

The on/off valve and elbows can be seen as weak points but after using both for 5 years without issues, I have confidence in their use and reliability.
The elbows can be eliminated but then the hoses would have to route over my shoulders and the valves would stick straight out.
I like them streamlined under my arms. Here's a few pics:
View attachment 674826
This is the current configuration I dive when I dive doubles to reach my NDL. There are the same 2 SPGs and LP inflator, no octo reg. The next picture is the same rig with one AIR 2nd stage connected to 2 1st stage and a octo reg on the right hand 1st stage, left tank in the picture.

View attachment 674785
Sans B/P wing What can't be seen here are 2 SPGs, 1 2nd stage with elbow and inline on the 1st stage on left side of the picture. It is actually the right hand tank. The yellow hose protector was on the hose was on when I acquired it in a used reg purchase.

View attachment 674794
This shows that the left tank is "on" in use, the right tank "off" not in use
View attachment 674795
This shows the right tank "on" and the left "off"

I'm surprised nobody else has come up with this. All the benefit of backmount doubles without the manifold. I guess the drawback is that you've got an extra hose to manage. Not the end of the world, but that's a pet peeve of mine.

Personally, I did the sidemount id doubles thing. It works fine, but I think I'm pretty much done with double tanks. I just had my third back surgery two months ago, and at this point I'm just hoping to lift a single tank rig next summer.