Second stage connection

[AfterDark]

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).

Done that years ago, a keen observer would have seen one in the 1st picture evidently you are not.

Well there is a saying about standing the test of time, I think it applies here.

Perhaps you should take better care of your gear? Two shutoffs fail in how long a period of time?
I've used those same 2 shutoffs with no failures for quite awhile add to that the 3rd one I use on my DBLhose no failures. I heard the same claim of failures 10 years ago when I posted my backup light mounted on my left shoulder on a .........RETRACTOR OMG! Even had one ninny tell me I was going to become entangled because a knife can't cut wire! The EFin things are made of plastic twist and break the cheap plastic hook snap! How these kind of people survive I do not know. Since then I bought 2 more retractors and again no issues or failures.

I use warm tap water to rinse my gear and leave the regs to soak until the water cools off.

 

[sea_ledford]

I think the set up os cool! It's a clusterf!@k of complexity, but it's still cool.

I was going to comment that it seems an awful lot of work to prevent a conversation with DMs and 3 or 4 reg switches, but apparently that's what you were after! Good job!

 

[AfterDark]

I think the set up os cool! It's a clusterf!@k of complexity, but it's still cool.

I was going to comment that it seems an awful lot of work to prevent a conversation with DMs and 3 or 4 reg switches, but apparently that's what you were after! Good job!

Just eliminating regulator switches. DMs do not concern me. One time a DM saw me with my mask on my head like I've been doing since I was 10 years old. He told me .25 every time he sees me do that.
I told him ok but it will be coming out of your tip at the end of the day.

It is not really complex but it does have a lot of connections. In use it just comes down to tank switches and air management by pushing one valve up the other down to switch tanks.

The inlines are right in front of my face easy to find. To open move the inline switch in the direction of the air flow, intuitive I don't need to see it. To close is down towards/against the air flow.
The 2nd stage is necklaced and the hoses route under my arms not over my shoulders.

 

[Angelo Farina]

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.

At the end of the seventies my friend Marco (another CMAS instructor) did buy the Pilot, as he was beginning to dive very deep (more than 60m with air), Below 75m the 109 was not performing so well anymore, so the Pilot was needed.
The Pilot was fine down to 100m, but then the limiting factor became the first stage, the first gen MK5, the one without SPEC and with just two LP ports, was limiting the air flow at such depths. So he started using his two MK5 first stages connected with the two posts of his twin tanks, with two LP hoses feeding the Pilot on both sides. I did never dive with him below 60m, but he reported that the improvement was clearly perceivable, and this was the reason for using a Pilot with two LP hoses and two first stages.
However, one or two years later Scubapro released the new version of the MK5, with the SPEC chamber and the multiport turret, including a central "high flow" port and the new "high flow" hose. Using it, the Pilot was fed with enough air with just one first stage, so my friend did buy the new MK5 and got rid of the second hose.
When using the Pilot with two hoses, he was using the second IP port of the right MK5 for connecting a 109, and the second IP port of the left MK5 for connecting the BCD hose.
So the setup was very similar to the one used by @AfterDark .
At that time twin tanks did not have a separation manifold, but they had a a separation RESERVE.
So any concern of having the system freeflowing and wasting all the air was simply a no-problem.
For such deep dives Marco was always carrying a third tank for deco, and this was enough redundancy in case of failure of the Pilot.

 

[AfterDark]

@Angelo Farina the main difference between Marco's setup and mine is the Pilot 2nd stage and the inlines. With my setup the AIR only need contend with one IP at a time because the tank not being used is not feeding the AIR. Both my tanks will end the dive with approx. the same psi regardless of the 1st stage IPs. Both 1st stages have IPs within +/- 5psi, that small of a difference isn't going to be noticed using the AIR with the diving I'm doing these days. If it becomes an issue I've got MK5 service kits and spring shims just waiting to be installed.

 

[Angelo Farina]

@Angelo Farina the main difference between Marco's setup and mine is the Pilot 2nd stage and the inlines. With my setup the AIR only need contend with one IP at a time because the tank not being used is not feeding the AIR. Both my tanks will end the dive with approx. the same psi regardless of the 1st stage IPs. Both 1st stages have IPs within +/- 5psi, that small of a difference isn't going to be noticed using the AIR with the diving I'm doing these days. If it becomes an issue I've got MK5 service kits and spring shims just waiting to be installed.

Did you try keeping both inline valves open at the same time?
If the two first stages are well matched, you possibly could get an even usage of the two tanks, removing the need of periodically alternate their usage.

 

[AfterDark]

Did you try keeping both inline valves open at the same time?
If the two first stages are well matched, you possibly could get an even usage of the two tanks, removing the need of periodically alternate their usage.

I need to make sure the AIR is good with a dive using it as a primary, a formality really but I'd like to know for sure. Yeah, after that I'll get it together for real not for photos and do a few dives with it and try that out. I need to finish the refinishing job on my steel 50's and use those, a lighter load than the 72's in the picture.

 

[lexvil]

While I’m a fan of the AIR 1, it may be a good idea to run a safe second during the testing.

 

[James79]

While I’m a fan of the AIR 1, it may be a good idea to run a safe second during the testing.

Earlier in the thread he details having a 109 on the right hand 1st as an octo/safe second.

 

[lexvil]

Earlier in the thread he details having a 109 on the right hand 1st as an octo/safe second.

Ok, missed it when I looked at the pic. Got the 25 and bits today.