Second stage connection

[rx7diver]

@AfterDark,

I didn't see this mentioned above, but I don't think things can get much simpler and safer for a solo diver diving deeper depths, than diving independent doubles (with a complete reg on each cylinder), and diving sixths. If you prefer to dive them back-mounted, and your rotator cuff issues make it impossible for you to reach your valves, then have you thought about inverting the tanks?

You could still use your nylon tank straps (rather than SS doubles bands). Your only additional cost would be custom-length reg, SPG, and inflator hoses. And you would probably want some valve protectors (so you can stand up the upside-down cylinders).

ETA: Poseidon Odins (for example) don't care which side (left or right) they're worn on.

rx7diver

 

[happy-diver]

Mate I've set your rig as my desktop background and still getting off
on the humongous amount of extra Orings you've got going in there

I showed your rig to this no extra Orings zealot party pooper scooper

and well, you can see the result


I've got four Air 1 might bolt them all together and play em like a harp

Anyone that builds this kinda stuff has my vote!



Ultra ultra ultra ultra magnificent!

 

[AfterDark]

@AfterDark,

I didn't see this mentioned above, but I don't think things can get much simpler and safer for a solo diver diving deeper depths, than diving independent doubles (with a complete reg on each cylinder), and diving sixths. If you prefer to dive them back-mounted, and your rotator cuff issues make it impossible for you to reach your valves, then have you thought about inverting the tanks?

You could still use your nylon tank straps (rather than SS doubles bands). Your only additional cost would be custom-length reg, SPG, and inflator hoses. And you would probably want some valve protectors (so you can stand up the upside-down cylinders).

ETA: Poseidon Odins (for example) don't care which side (left or right) they're worn on.

rx7diver

Many years ago I considered inverting my tanks but decided it was too much trouble and expense. Also the weight goes up because due to valve protection. In Europe upside down small doubles were a "thing" 30 or so years ago. I 1st started using IDs in the 1980's and I have still not found the need to be to reach my valves. When I 1st started using IDs I did drills removing the tanks from my back and wearing them on chest to be able to turn the valves, it was all for not, 30+ years later I still have never had to do it for real. Since I'm slowing down, diving less, doing different and more benign dives I suspect I'll never be in a situation that requires tanks removal.

I maintain my gear and confirm everything works pre dive. Before I use this rig I'll soap bubble test all the connections after I check each one for tightness. As I've post several times now, this is the same basic rig I've used for years, the only change I've made is remove 2 second stages and replace them with one and add a 2nd stage to the right hand 1st for donation. When I have 2 second stages either one can be used for donation. The elbow and valves are old friends no worries.

 

[AfterDark]

Mate I've set your rig as my desktop background and still getting off
on the humongous amount of extra Orings you've got going in there

I showed your rig to this no extra Orings zealot party pooper scooper

View attachment 674706

and well, you can see the result


I've got four Air 1 might bolt them all together and play em like a harp

Anyone that builds this kinda stuff has my vote!



Ultra ultra ultra ultra magnificent!

Mate, I like cut of your jib! When are you going unveil your version of this rig? Surly with 4 AIR 1 you are going to at least try it out? play em like a harp LOL!! Maybe you can get a crowd of those extra Orings zealot party pooper scooper together and cull the herd a bit, sorta speak.

 

[AfterDark]

Here's a few shot of my double hose setup.
Is that an elbow and on/off switch on that 156?

Oh my lord it is!!!!

Oh no how many O rings are in that LP splitter?!?!

Another O ring death trap by AD!

 

[halocline]

I remember someone else on the vintage forum came up with the idea to feed a pilot with 2 first stages. I thought it was a bad idea because it basically turns the entire loop from one first stage to the other into a big IP chamber with multiple failure points, including the fact that a free flow caused by a 2nd stage malfunction will drain both tanks. I haven't looked closely at all the details of your proposed set up, but it looks very complicated to me and in the end you still have less redundancy because you are relying on one 2nd stage for all your back gas.

It's your decision to dive however you want, but I just don't see why you would go to such lengths to avoid regulator switching. It's a simple and easy skill that every sidemount diver quickly learns on every dive. If there's any problem with removing a 2nd stage from your mouth momentarily during a dive, that is clearly a technique issue, not a gear issue. I'm sure you know that, you've been around a long time, but I'm only bringing it up because I don't understand what other benefit this set up provides, at the expense of less redundancy and way more complexity.

But, if you are going to do it, please avoid using an Air1 or pilot for it. Those 2nd stages have a quirk where the diaphragm, acting also as an exhaust valve, can collapse in an uncontrolled free flow. It's happened to me a few times, and the venturi assist in that situation is very strong. And they breathe really wet inverted. So even though I love my pilots, I don't use them cave diving, only single tank OW dives. For cave diving I use 109s (converted to balanced) or D300s, both of which I never have any problems with on dives and could fix underwater if necessary.

If I've misunderstood your configuration or reason for using it, I apologize.

 

[AfterDark]

I remember someone else on the vintage forum came up with the idea to feed a pilot with 2 first stages. I thought it was a bad idea because it basically turns the entire loop from one first stage to the other into a big IP chamber with multiple failure points, including the fact that a free flow caused by a 2nd stage malfunction will drain both tanks. I haven't looked closely at all the details of your proposed set up, but it looks very complicated to me and in the end you still have less redundancy because you are relying on one 2nd stage for all your back gas.

It's your decision to dive however you want, but I just don't see why you would go to such lengths to avoid regulator switching. It's a simple and easy skill that every sidemount diver quickly learns on every dive. If there's any problem with removing a 2nd stage from your mouth momentarily during a dive, that is clearly a technique issue, not a gear issue. I'm sure you know that, you've been around a long time, but I'm only bringing it up because I don't understand what other benefit this set up provides, at the expense of less redundancy and way more complexity.

But, if you are going to do it, please avoid using an Air1 or pilot for it. Those 2nd stages have a quirk where the diaphragm, acting also as an exhaust valve, can collapse in an uncontrolled free flow. It's happened to me a few times, and the venturi assist in that situation is very strong. And they breathe really wet inverted. So even though I love my pilots, I don't use them cave diving, only single tank OW dives. For cave diving I use 109s (converted to balanced) or D300s, both of which I never have any problems with on dives and could fix underwater if necessary.

If I've misunderstood your configuration or reason for using it, I apologize.

Well you certainly have a lot to post for someone who hasn't read the details. You even got a like from a now lurker evidently, how nice! No need to apologize my friend. I would suggest you read the details and understand my long history of using back mounted ID's as a matter of fact this same setup with 2 156's complete with elbows and inline shutoffs sans octo 2nd stage has been my solo rig for the past 5-6 years. Before that sans elbows and inline shutoffs with back then 2 109's it's use by me dates back to the 1980's and I mean everything you see in the 1st picture except for cool OMS DTA, back then it was SS bands and also the PDC in the console. The regs, tanks, all have hundreds of trouble free diving hours to their credit. The were regs upgraded by me to 156s. The hoses have all been changed since then.


Regulator switches are nothing new to either I could probably do them narc'd, there really is no skill involved just remove one and replace it with another, any trained chimp could to that on the 3rd try I'd bet but, I say why should I bother if I can change it? It only cost me to have the AIR serviced everything else I already have and use. All your concerns are addressed on page 2 post 10 I think go read it and get back to me if you'd like, I would.

 

[halocline]

Well you certainly have a lot to post for someone who hasn't read the details.

I didn't say I haven't read the details. I said I haven't looked closely at them, which means carefully considering every aspect of every detail of what you wrote. I'm sorry I wasn't clearer.

Bottom line, you are removing redundancy in the form of an alternate 2nd stage for your back gas, for no apparent reason other than the convenience of not having to switch regulators. You are also adding considerable complexity to a long proven system of diving. You posted this thread presumably to get some feedback on this set up. I gave you mine.

 

[AfterDark]

I didn't say I haven't read the details. I said I haven't looked closely at them, which means carefully considering every aspect of every detail of what you wrote. I'm sorry I wasn't clearer.

Bottom line, you are removing redundancy in the form of an alternate 2nd stage for your back gas, for no apparent reason other than the convenience of not having to switch regulators. You are also adding considerable complexity to a long proven system of diving. You posted this thread presumably to get some feedback on this set up. I gave you mine.

I need to edit some of this post
I don't understand how adding a 2nd stage reduces redundancy perhaps you can enlighten me, please . The inlines isolates the AIR from a 1st stage failure and out of control free flow, by turning off the inline the free flow is redirected to the OVR on the 1st stage and the AIR becomes useable on the other tank to end the dive and surface. If I use this rig on charters I need a donation regulator, in the past with the 2 second stages that wasn't an issue but with one 2nd stage it does.

The 2nd stage on the right tank is the redundancy in case of a 2nd stage AIR failure. The air remaining in one tank at anytime during the dive is enough to get me home if I've done my switches on time. Which I always do.

no apparent reason other than the convenience of not having to switch regulators It is the only reason other than those AIRs breath really nice!

 

[grantctobin]

I remember someone else on the vintage forum came up with the idea to feed a pilot with 2 first stages. I thought it was a bad idea because it basically turns the entire loop from one first stage to the other into a big IP chamber with multiple failure points, including the fact that a free flow caused by a 2nd stage malfunction will drain both tanks. I haven't looked closely at all the details of your proposed set up, but it looks very complicated to me and in the end you still have less redundancy because you are relying on one 2nd stage for all your back gas.

It's your decision to dive however you want, but I just don't see why you would go to such lengths to avoid regulator switching. It's a simple and easy skill that every sidemount diver quickly learns on every dive. If there's any problem with removing a 2nd stage from your mouth momentarily during a dive, that is clearly a technique issue, not a gear issue. I'm sure you know that, you've been around a long time, but I'm only bringing it up because I don't understand what other benefit this set up provides, at the expense of less redundancy and way more complexity.

But, if you are going to do it, please avoid using an Air1 or pilot for it. Those 2nd stages have a quirk where the diaphragm, acting also as an exhaust valve, can collapse in an uncontrolled free flow. It's happened to me a few times, and the venturi assist in that situation is very strong. And they breathe really wet inverted. So even though I love my pilots, I don't use them cave diving, only single tank OW dives. For cave diving I use 109s (converted to balanced) or D300s, both of which I never have any problems with on dives and could fix underwater if necessary.

If I've misunderstood your configuration or reason for using it, I apologize.

There’s a great Twain quote with to do with wrestling and a farm animal. I’ve made my case and you’ve asserted that both my and @halocline claims are baseless because you haven’t experienced them in your aeons of diving. To note, I’ve had two shutoffs fail. One generic OEM as you’ve posted in your images, and one Omni-Swivel. If you’re going to continue using them, please put an OPV on each first stage in the event of runaway IP, as the shutoff will prevent your second from being one AND not all second stages free flow before something else does (see @DA Aquamaster posts for references on that).