Using AIR 2

[rhwestfall]

Of course, my setup is the best

Nope, mine is....

And my mother can...

 

[Angelo Farina]

I find it interestng that the US and European (including UK, whether they like it or not) approaches differ in what problem they are most concerned about. In the US the focus seems to be on OOA emergencies and seem to assume that equipment failure, specifically in the first stage are unlikely. The emphasis is on alternate sources of air, either a fully redundant twin, pony, or a buddy to supply air. On the other hand, the European setup seems more concerned with regulator failure, emphasizing redundant first stages on a single air source.

I think the difference is fairly subtle in the real world, but interesting none the less.

I can answer for Cmas (Bsac usually is very similar).
The recommendation for two independent regs on two separate valves is due not specifically for addressing the risk of a first stage failure (which is rare), but for addressing the most frequent cause of OOA emergencies triggered by an hardware failure, that is air loss due to a free flowing second stage (either the primary or the secondary) or by an o-ring failure.
In Cmas we teach students to quickly close the valve of the free-flowing reg and to breath from the other. Ideally the two regs are identical, with a recommendation to have a slightly longer hose on the one designed to be donated to a buddy. An Air2 is welcome, but just as a third additional air source.
In the american system, the octopus is primary aimed to be donated, not to be used by the owner, as when a problem occurs, both the primary and the secondary are affected, and the diver should rely on the additional air source OF HIS BUDDY, not his one.
Here instead we prefer a more self-reliant approach. When the primary reg fails, before asking air to his buddy, a diver should usually be able to get air from his own completely independent secondary reg.
Which should get gas from the main tank, or optionally from a pony.
Here we do not recommend a single small tank with a single valve.
We recommend a large main tank, carrying at least 3000 liters, or better 3500 (15 liters × 232 bars provide 3480 liters).
A reserve valve ensures that, even if the diver is slow closing the valve of the free flowing reg, the tank will not get empty. After closing the affected valve, you pull the reserve and you get at least 50 bars, that is 750 liters: plenty enough for a slow ascent and a safety stop.
A manifolded compact twin tank can provide the same degree of redundancy, but only if the dive is done with the manifold valve closed, and breathing alternatively from the two regs, as with two separate tanks in side mount.

 

[lexvil]

Nope, mine is....

And my mother can...

…tie her combat boots faster…

 

[johndiver999]

Going off on a tangent (because this is SB)...

Since I've started diving with a pony I've been thinking that it gives me another option for donating air, which is to just give them the pony and send therm up on their own while I follow on my back gas. Sure, if someone is panicking and need to be managed then primary donate and control the ascent, but if they are fine, but having an equipment failure or uncomplicated OOA and can manage themselves, I'm liking the though of giving that another 40 CuFt of air and not needing to be physically attached to someone else.

Thoughts?

Have you ever heard of anyone doing this, for real?

 

[CT-Rich]

I have been using an AIR2 for about 10 years. I did adjust the cracking pressure so it draws a little hard and doesn’t dribble air. I do like those suggesting it is death trap because of the venting on accent issue. TBH I use the dump valve on the right shoulder of my BCD. I haven’t held a power inflator over my head in years.

I haven’t seen any one deploying their Octopus to make sure it works in ages. I test my Air2 pretty often because I handle it on every dive, it’s right there. I find it every time I add air to my BCD. I never really understood the fear mongering that surrounds them. I don’t think I would use if I was a DM or instructor or anyone else with a high probability of being mugged for air, but that has not been issue for me.

I put the dislike of AIR2 in the same class with people that complain about fins, dive watches/DC and gear that is marginally gadgety. They didn’t buy it, haven’t used used and still feel like they need to have a rabid opinion on it, based on?

 

[OMyMyOHellYes]

I put the dislike of AIR2 in the same class with people that complain about fins, dive watches/DC and gear that is marginally gadgety. They didn’t buy it, haven’t used used and still feel like they need to have a rabid opinion on it, based on?

Jealousy. Shear jealousy.

 

[happy-diver]

I say to those that despise this instrument such that you learn said instrument intimately
for when you will ultimately be challenged by becoming a rampaging horde of divers all
mouths open, no air to breathe, nightmare for some, AIR2 aficionados you may become

 

[John C. Ratliff]

I can answer for Cmas (Bsac usually is very similar).
The recommendation for two independent regs on two separate valves is due not specifically for addressing the risk of a first stage failure (which is rare), but for addressing the most frequent cause of OOA emergencies triggered by an hardware failure, that is air loss due to a free flowing second stage (either the primary or the secondary) or by an o-ring failure.
In Cmas we teach students to quickly close the valve of the free-flowing reg and to breath from the other. Ideally the two regs are identical, with a recommendation to have a slightly longer hose on the one designed to be donated to a buddy. An Air2 is welcome, but just as a third additional air source.
In the american system, the octopus is primary aimed to be donated, not to be used by the owner, as when a problem occurs, both the primary and the secondary are affected, and the diver should rely on the additional air source OF HIS BUDDY, not his one.
Here instead we prefer a more self-reliant approach. When the primary reg fails, before asking air to his buddy, a diver should usually be able to get air from his own completely independent secondary reg.
Which should get gas from the main tank, or optionally from a pony.
Here we do not recommend a single small tank with a single valve.
We recommend a large main tank, carrying at least 3000 liters, or better 3500 (15 liters × 232 bars provide 3480 liters).
A reserve valve ensures that, even if the diver is slow closing the valve of the free flowing reg, the tank will not get empty. After closing the affected valve, you pull the reserve and you get at least 50 bars, that is 750 liters: plenty enough for a slow ascent and a safety stop.
A manifolded compact twin tank can provide the same degree of redundancy, but only if the dive is done with the manifold valve closed, and breathing alternatively from the two regs, as with two separate tanks in side mount.

Angelo,

This is interesting to me, being a vintage diver, as I feel that the newer, more modern regulators with this tendency to free flow extensively without being able to stop it is a result of over-engineering the first and/or second stage. Free flow can occur because of a regulator malfunction, whereby the first stage doesn’t stop the flow at the assigned IP. This is a regulator malfunction, and should be quite rare. Dacor years ago patented an anti-free flow second stage for regulators which were quite sensitive, which meant that these Dacor second stages would stop free flows in about 4 seconds. The idea did not catch on (maybe because of Dacor’s patent, but that’s now expired).

I feel that piston first stages are perhaps more prone to this type of malfunction due to reliance on O-ring(s) to maintain the pressure differentials. The diaphragm second stages are not immune, but would have to have something really break before this type of malfunction (not stopping flow at the IP) would occur.

Now, like I said, this diver is a vintage diver, and I dive double hose regulators extensively. The Mistral-type regulator (upstream single stage) such as the U.S. Divers Company/Le Spiro Mistral, the Healthways Gold Label Scuba regulator, and earlier versions were pretty well immune to this type of malfunction, and with only about 6 moving parts, very easily serviced. Maybe that’s why J.Y. Cousteau preferred the Mistral to all the other regulators that came out subsequently.

SeaRat