Redundant Octos & 2nd Stages Unable to Deliver Air?

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I was at 110' descending in Lake Michigan and my primary started to freeflow. If I had switched to my pony the dive would have ended before we saw the best preserved wooden ship I have ever seen. My octo was there, I used it until I could ascend 10' and clear the freeflow. Lost 200psi, but was able to continue the dive without further incident. So, I dive with three, I want access to that large tank of gas if I can get it.
 
I was taught to ditch the octo if using a pony. Too many regs and the chances your primary second stage won't work and the oct will are very low.

That said, if you sling your pony I don't think keeping the octo is that much of an issue as the chance of you mistaking the pony reg for the octo is smaller, if you BM the pony, then definitely get rid of the octo. Personally, I'd ditch the octo just to keep it clean.
 
I was at 110' descending in Lake Michigan and my primary started to freeflow. If I had switched to my pony the dive would have ended before we saw the best preserved wooden ship I have ever seen. My octo was there, I used it until I could ascend 10' and clear the freeflow. Lost 200psi, but was able to continue the dive without further incident. So, I dive with three, I want access to that large tank of gas if I can get it.
You could have cleared in while on the pony and then went back, no?
 
Sorry, I suppose to be the guy who triggered this duscussion with my posts about the way I used ny pony in a far past time..
I must clarify that I did never talk about "ditchibg an octopua" when using a pony.
I do not like the octopus.
Of course I had to use it several times, whenever tanks with double valves were not available.
But when tanks with double valves are available, I prefer to use two fully independent regs, particularly if it is a twin tank.
Most tanks here are single, steel, 15 liters, 232 bars, no reserve, convertible DIN/yoke. So this is what I can easily rent here, and what I use mostly (with two separate complete regs).
However, for demanding dives (solo, overhead, deco, strong currents, low visibility, etc.), or when there was some serious chance of being separated by my buddy, or when I was responsible of other divers as I was working as an instructor or DM, I did choose to add also a pony to my basic setup of a large tank with two fully independent regs.
At this point the choice is between moving one of the two regs from the main tank to the pony, or to simply add a third complete reg for the pony.
In the end I prefer the second option. This allows to give air to two buddies/students simultaneously (which happened to me in half a dozen of cases), or to continue the dive using the second main reg, when the first one fails (usually due problems at the first stage - and this is the reason for which I do not like an octopus, as in my experience the first stage fails much more frequently).
So I do not see the problem being discussed here: if the main tank has only one valve, so the basic setup is a single first stage and two second stages, when you add a pony there is no reason for keeping the crap octopus, it becomes substantially useless and can only become cause of problems (i.e., freeflowing and you cannot close its valve).
Better to leave only one reg on the main tank, and add another on the pony.
When instead the main tank, as in my case, has two valves and two fully independent regs, I would prefer NOT to remove one of them.
We are talking on adding a pony because an extreme dive is planned, so you need all the possible gas reserve and all the possible redundancy.
If the conditions are not so extreme, then I happily remove the pony, not my second fully independent reg on the main tank, which is also a decent redundancy for mild risk dives, without the inconvenience, weight and risk of entanglement caused by the pony tank.
So I use 3 setups only:
1) small tank (11l) with single valve and reg with octopus: diving at less than 10m, in super-benign conditions (warm water, no current, perfect visibility, proven buddy, possibly no suit and no BCD)
2) normal main tank (15l) with double valves, two fully independent regs: normal recreational dives with wife or sons as buddy (wearing the same equipment). This is what I did use in the last 30 years for most of my dives.
3) large main tank (possibly twin) with reserve and plus a pony, with a total of 3 fully independent regs: extreme dives with deco stops or overhead, or when responsible of a group of beginners. I did the last dive in this configuration more than 30 years ago.
I know that some divers use an intermediate setup, using a small 11-liters tank with single valve plus a pony, for dives corresponding to my profile n. 2).
I prefer my setup n. 2) for these dives, avoiding the bulky pony, but I understand that not everywhere you find 15-liters tanks with double valves, hence this hybrid setup of a small 11l tank plus pony (without octopus, of course) can be the only available option for getting some redundancy in such places.
 
You could have cleared in while on the pony and then went back, no?
No, that several minutes on the pony at 110' means the pony will be short for when it is needed. No, I am not planning it that close, but for the same reason I don't want it that close either, and a couple minutes can make it that close. So, if I put it in my mouth I am starting my ascent, no other option, period. BM pony only. I necklace the Octo and color code the pony regulator to avoid any confusion of regulators. Primary around my neck, octo on necklace and pony reg on magnet on right abdomen with tucked hose. I have no issue with confused regulators. I switch between pony and no pony very often and too lazy to remove reg. So I have adapted and it works for me.
 
A torn diaphragm or failed exhaust valve makes a second stage useless. Not something that would likely occur in the middle of a dive, but either one would do it.
I believe on my regulators, you could breathe by pressing the purge button, but that would obviously be FAR from ideal. During open water we practiced breathing from a regulator positioned below us, but off the bubbles and pressing the purge button. I don't think I've ever done that again since.
 
Sorry, I suppose to be the guy who triggered this duscussion with my posts about the way I used ny pony in a far past time..
This was a topic I've been curious about for some time, and have actually learned something because there does seem to be several ways a 2nd stage might stop working, but the octo would still be useful.
This allows to give air to two buddies/students simultaneously (which happened to me in half a dozen of cases), or to continue the dive using the second main reg, when the first one fails (usually due problems at the first stage - and this is the reason for which I do not like an octopus, as in my experience the first stage fails much more frequently).
Interesting use case. This is a good example of tailoring your equipment to the dives you do.
 
A torn diaphragm or exhaust does not make the reg unusable. If calm, you can press the purge and carefully inhale fro the stream of bubbles.
 
How about this one that i witnessed earlier this year:
A diver was very close to a small (3 footer) Giant Pacific Octopus, modeling for photographers. Suddenly the gpo grabs her primary reg and snatches it away! We helped her get the secondary as the octopus was not letting go!
Gods Pocket May 05, 2023-58.jpg
 
I have had a full failure at 60 feet. First stage failed closed with still 2500psi. left in tank.
Pony bottle bailed me out. This was a result of inadequate reg service. Yes lesson learned. The second stage is a good idea if you are diving with a buddy. But as indicated above, there is buddy breathing. But creates more of a task load. A positive scenario is when you are sick and required to blow chunks. You switch to the octopus, do your business, then switch back to your primary. I have twin tanks, a manifold with 2 first stages . one has a octo for myself. the other has a octo on a 9 foot hose, for someone else. In a perfect dive they are never used. But better safe than sorry.
Make sure they are properly maintained.

Hope this helps.
 

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