A fair and balanced look at Air2s and other combination inflators

[KeithG]

If you're getting it serviced at a dealer, it shouldn't matter. Especially if they're honoring the parts for life program. DIY? That might be an issue, but not an insurmountable one.

i was thinking more about issues in the field since i now DIY my regs because all of my LDS haven proven that they are incompetent when it comes to servicing our regs. having them try to properly service 2 different things?

we had a "false" issue at CoCoView a while ago. The DM rejected my divebudys reg since it was "leaking". I was forced to take it to the shop, but at least the reg tech knew his stuff. When i returned and reported that reg tech had declared the reg was in perfect order the DM was still not convinced it was okay to use. I had to explain the Sherwood dry bleed system to the DM to make them happy.

 

[2airishuman]

Thank you to everyone who moved the discussion forward.

The shoulder dump presents a potential problem as the pull dumps are typically hard to have fine control. Unlike the lower dump where you can reach back and pull the line while pushing against the dump allowing very precise control, the pull dumps are basically on/off, and can encourage stepwise ascents. Not a huge problem, but something that does remove a bit of precise control. With a typical inflator, the proper way to control the ascent while vertical is not to hold the inflator above your head, but to hold the deflate button down the whole time in the normal position, and raise and lower the whole inflator so that the wing auto-dumps itself as you ascent. You control the ascent rate by raising or lowering the inflator to control the amount of air in the wing/bcd. Very very few divers do this, very very few instructors know how to do this and teach it, but it's something that the Air2 absolutely can't do.

You can do that with an Air2, but not while sharing air.

I wasn't trained that way but might try it sometime. Interesting.

3. absolutely not true. The secondary length is definitely able to be fixed. Here's why. Your neck should always be in the same position relative to the first stage, regardless of how tall you are, how big you are, etc. if the rig is adjusted so the first stage is in an appropriate position. There are typically 2 hose lengths, 22" and 24" *depends on how your first stage is setup, the 24" I see with doubles kits where the hoses come down first then over I.e. Apeks Tek3/DS4, but for singles and most regulators now, the 22" is perfect*. I use shorter hoses because my Poseidons stick out farther than normal regulators for the hose connection, but 22" is probably the most common length.

Physiology varies. I have more back curvature and a longer jaw than many people and need a longer hose as a result.

4. If you're using a backmounted pony, why do you need 3 second stages? If you can't breathe on your primary any more either due to a failure or having donated it, why would you want to breathe on the Air2, and if you are, why carry the pony?

One configuration, which CuzzA and dumpsterDiver use, involves connecting the pony to the under-chin regulator. That makes it readily available and easily identifiable as the pony reg. The Air2 would then be used in an air sharing situation. I use a slung pony instead.

Why is a "safe second" or "octopus" or "combination inflator" even *necessary* at all for recreational diving?

It is my understanding that buddy-breathing ascents are no longer taught because there were too many student injuries while learning the skill.

Even if I were in a buddy team that had that skill, I would want to be able to assist another diver outside my buddy team in an OOA situation.

They are not standardized and each may look quite different. A standard inflator has the dump on the end. Inflate on the side. No confusion even when a mfg uses a fancy one. I have seen this happen in a class when even after going over two different types of integrated inflators (Scuba Pro and Aqualung) a student not used to seeing them had some difficulty deciding which one to push. Another item is the size. Someone with very small hands may have difficulty as well manipulating it.

+1, I had never considered that.

Stop posting on stuff you have never used in open water

Stop reading my threads if you don't like them.

 

[CuzzA]

This may be worth the watch for anyone considering a 5th Gen Air2.


http://www.scubapro.com/media/399498/press_release_2015_08_air2.pdf

 

[tbone1004]

One configuration, which CuzzA and dumpsterDiver use, involves connecting the pony to the under-chin regulator. That makes it readily available and easily identifiable as the pony reg. The Air2 would then be used in an air sharing situation. I use a slung pony instead.

uhh what? Why would you use the air2 in an AAS situation when you have a pony regulator under your chin that like is going to breathe better, but certainly as well as the Air2, is more comfortable to breathe on, easier to access, and is coming from an independent gas source that because you're a smart person, did the rock bottom calculation on how much gas you need to get up? I just don't see why you would need 3 second stages for an open water recreational dive when we only need 2 inside of a cave where things like CESA's aren't an option

 

[CuzzA]

uhh what? Why would you use the air2 in an AAS situation when you have a pony regulator under your chin that like is going to breathe better, but certainly as well as the Air2, is more comfortable to breathe on, easier to access, and is coming from an independent gas source that because you're a smart person, did the rock bottom calculation on how much gas you need to get up? I just don't see why you would need 3 second stages for an open water recreational dive when we only need 2 inside of a cave where things like CESA's aren't an option

Right, I would donate my primary and switch to the pony.

IMO, there should be a good reason why someone would use an air2. One less hose and standard reg isn't a good enough reason. The only reason I can come up with is where a slung pony is not an option for the type of diving the individual is doing. Therefore, back mount it which would require the pony reg to be necklaced or clipped off somewhere easily accessible. Now you're managing 3 regs, which would be a little messy and could cause confusion. In that case, the Air2 makes sense.

 

[2airishuman]

uhh what? Why would you use the air2 in an AAS situation when you have a pony regulator under your chin that like is going to breathe better, but certainly as well as the Air2, is more comfortable to breathe on, easier to access, and is coming from an independent gas source that because you're a smart person, did the rock bottom calculation on how much gas you need to get up? I just don't see why you would need 3 second stages for an open water
recreational dive when we only need 2 inside of a cave where things like CESA's aren't an option

I suppose you could ask DD but I don't know how to get reach him now that he is no longer on SB. As I understand it:
1) It makes the configuration modular since they then still have an alternate air source when diving without the pony
2) It allows gas from the primary cylinder to be shared. DD dives with a 13 cf pony, I believe. There is not an SPG for the pony that is visible during the dive, and the tank valve for the pony cannot be reached without removing kit. I think it's an interesting question how much gas you have to be prepared to share, but 13 cf under those circumstances probably isn't enough.

When I am on a recreational dive with a pony/stage bottle, it's slung, and it has its own reg bungeed to the bottle. I don't get rid of the secondary under my chin just because I have it. I don't think you would in a cave, either.

 

[tbone1004]

that's because we don't use pony bottles in a cave. If you need/want redundancy, dive a redundant rig, don't half a$$ it with an undersized pony bottle.

1. I can see that, but then why dive with the pony at all?
2. dive an appropriately sized pony bottle if you're going to dive one, or go to a redundant rig. Whether you do a 2 tank dive on a set of doubles, or a pair of singles is the same amount of space on the boat. Less if you have the pair of tanks plus a pony bottle. Same amount of regulators, but more tanks to maintain. I'm a firm believer that if you feel you need redundancy then go to doubles or sidemount, pony bottles are a waste.

if you're not removing the secondary under your chin, then why are you bringing the pony bottle? If you fear for a first stage failure, dive an H-valve, if you fear for running out of gas, manage your gas better. If you want an independent gas source in case you have to share air, then dive doubles or sidemount. I have a pair of bands that use cam bands to mount independent tanks for doubles. I take it with me when I am going somewhere that I want to dive doubles but do not have access to a set of doubles. Sure I can't shut down my left tank easily since it is a pair of righty valves, and you have to dive them like independent doubles, but it's better than dragging a pony bottle around.

 

[2airishuman]

. I'm a firm believer that if you feel you need redundancy then go to doubles or sidemount, pony bottles are a waste.

if you're not removing the secondary under your chin, then why are you bringing the pony bottle?

I typically dive a single + slung pony on deep dives, typically anything over 30 feet. Often these are solo dives but I follow the same self-reliant practices whether I'm solo or with a buddy. Typically these are freshwater dives where deep equals cold. Less often, I use manifolded doubles.

For recreational dives, a pony bottle provides redundancy for a broad range of failures:
1) Most importantly, it provides safety in the event of rare, abrupt disruptions of the gas supply caused by mechanical failures, such as delamination of the 1st stage HP seat, blockage of the tank valve by a foreign object, or a failure of the valve neck o-ring.
2) It allows recovery from a 2nd stage freeflow caused by icing, without having to end the dive.
3) It provides an alternative source of gas in the event of running out of air due to, for example, a stuck SPG needle.

If you fear for a first stage failure, dive an H-valve, if you fear for running out of gas, manage your gas better.

How many dives do you have with H-valves? I tried it for a while, and found it to be a huge hassle:
1) The most serious problem is that with 7.25" diameter cylinders, which is what I use, the H valve handle is susceptible to damage and roll-on during transport, because it projects beyond the cylinder diameter.
2) I was unable to get truly satisfactory hose routing. The H valve outlet is lower than the main valve outlet, and the first stage I had in the H valve outlet would tend to hit my wing. My cylinders have modular valves on alternate sides, so I can make them up into manifolded doubles, and neither the left or right H valve configuration was ideal (though the routing problems were different).

H valves do nothing to address blockage of the dip tube, and they don't increase the total amount of gas available.

If you want an independent gas source in case you have to share air, then dive doubles or sidemount.

That's fine if you want to do it. Maybe it works for you.

I find that manifolded doubles are more difficult to handle above the water than individual cylinders of the same size, plus a pony, at least for shore dives, which is most of my diving.

I have a pair of bands that use cam bands to mount independent tanks for doubles. I take it with me when I am going somewhere that I want to dive doubles but do not have access to a set of doubles. Sure I can't shut down my left tank easily since it is a pair of righty valves, and you have to dive them like independent doubles, but it's better than dragging a pony bottle around.

I have a similar setup. It has its advantages in some circumstances particularly for long shallow dives. Typically it is heavier and less convenient for the amount of gas that I actually want to carry. If I am planning a dive where I am going to breathe 99cf and keep a reserve of 40cf split between two cylinders then the lightest possible configuration is a 120cf plus a 19cf. Double LP72s weigh more, double AL80s with necessary ballast weigh considerably more.

 

[tbone1004]

double 72's are roughly 60lbs empty. A 120 and AL19 is roughly 50lbs, so I'll give you that, but you have to add the ballast in there as double 72's will require significantly less ballast than a 120/19 combo. Somewhere between 8-10lbs, so if you're wearing that and can remove it, then you're at a wash. I also find them easier to walk around with than big singles because they sit close to your body and you don't have to make two trips or have a swinging bottle on your side that can catch any waves.

To each his own, I just don't see the point in them when light doubles are cheap and easy.

I don't like or advocate for H-valves for the same reason I don't like or advocate pony bottles.

 

[rhwestfall]

2) It allows recovery from a 2nd stage freeflow caused by icing, without having to end the dive.

That there is the #1 reason I dove with a pony on single tank dives in COLD water (Tobermory). Even on shallow(ish) dives like the Niagara II (which is usually one of the coldest damn dives in Tobermory), even at 70' compared to the Arabia or Forest City at >100'), I've seen freeze flow after freeze flow. Diving a 19 - 30 gives you the gas to get it shut down and thawed. You can also hand it off and ascend independently.

Nothing wrong with pony bottles...