separate octopus vs. bcd inflator/second stage combo

[RobPNW]

Like many divers, I started that way too. No more.
There are several issues in practice.
From a maintenance standpoint, unless it's easily detached like Atomic or Aqualung, a safe second rarely gets the same post-dive rinse attention that your main second stage gets. The spindle of the exhaust valve is quite prone to corrosion (except for the $300 titanium Atomic SS1), and I've serviced more than one safe second with a stuck-open exhaust valve. That could be a problem when you need buoyancy.
As for your question about the "hose dump", if you are referring to the cable pull dump on the bcd shoulder, you cannot use that while breathing from the reg except for the Aqualung model with a split linkage and the ability to pull on the hose center. And there was an old long thread arguing against using the pull dump in the first place. There is at least one photo circulating of a completely torn off elbow from too vigorous use of the cable pull.
But the real challenge is on a shared air ascent. Unless you practice it, controlling your own buoyancy as your bcd gas expands is a bit of a challenge with the reg in your mouth, and your other arm linked with your OOA diver. You may need to remove the reg to lift the hose to vent, if you fall behind with expanding gas, and you're already task loaded from the OOA emergency. Can be a challenge to avoid corking, especially if your buddy is panicked and you have to also reach over to vent his bcd, along with your own.
Defenders will say that "it's just practice", and they're right. But it's a poorer performing second stage; it's prone to corrosion, and having my necklaced second right there after handing off my primary is just too easy.

Understand all. I was referring to the Airsource from Aqualung with the exhaust half way up the corrugated hose. I'm one of those guys who needs to get my hands on something to get a feel for whether I trust it. That exhaust and the quick release sound like points of failure for little benefit but I would like to see one in person.

Honestly, I'm just joining what I think is an interesting discussion. I'm in the process of mentally building my new BP&W new kit and thinking through all the options and details first. I can get something similar to dealer cost on some of the regulators. So, for a little over a $100 more, I can get a SP G260 as an octo and have a duplicate of my primary on a necklace. Same model, both solid, same breathing, same maintenance etc.

 

[Curious_George]

The air mcdoodle is a great choice for divers who plan to never get into tech diving and find the complexity of a separate inflator/octo too much to keep up with. Great choice as well for those would otherwise constantly let their octo drag the bottom/coral. It’s also probably handy if one wants to breathe from their wing.

As has been said before - my octo is on a necklace right where I left it and plenty easy to find.

 

[Gareth J]

I really don't like combo units. I've tried a few, e.g. Scubapro and the Air2. I've also regularly seen it go to s*** when they've been used on courses and exercises. They where far more popular in the 90's than now. The disadvantage of having been an Instructor for a long time, is I have seen things go wrong and go well. Things that repeatedly go wrong are a warning bell, Air2's are in that category.

I would dive with you if you used a combo unit, if I was on a twinset, or any thing else where I had independent bailout. A conventional cylinder / regulator setup, then no. But on a conventional setup, you would be my AAS, and I really don't trust Air2's.

My CCR came with an Air2 when it left the factory. It was removed before I used the unit, and replaced with a regulator on a necklace. These days, they come with a BOV, which I now have fitted. In all the years I have had my unit, the only two modifications I have made, both when I first got it, was to remove the Air2, and to fit a backplate in place of the factory Harness.
On my course, the unit I had was fitted with an Air2. All of my dives, I carried a bailout cylinder, although the first day technically I didn't need to!

In fairness, I carry a bailout cylinder on 90% of my dives anyway. Thats because I mostly dive CCR. If not on CCR I'm on a twinset (for teaching). I have used a single cylinder once this year in open water, teaching. The only other occasion I dive single cylinder is on some overseas dives (not that I have been overseas this year).

 

[scubadada]

The air mcdoodle is a great choice for divers who plan to never get into tech diving and find the complexity of a separate inflator/octo too much to keep up with. Great choice as well for those would otherwise constantly let their octo drag the bottom/coral. It’s also probably handy if one wants to breathe from their wing.

As has been said before - my octo is on a necklace right where I left it and plenty easy to find.

It's just dazzling what stupid comments are made on SB. I dived an Air2 for many years, it was a perfectly adequate primary donate system, works just fine. The reg is at the same level as your exhaust hose, no deeper. Get yourself a couple thousand more dives before you think you are an expert in you comment.

 

[napDiver]

As others stated, it's all about your specific case. Diving environment, teammates, skill level, backup plan, etc...

My normal recreational setup diving with no overhead/deco ceiling, I have a primary donate 1st and an SS1 on a necklace.

Case 1: OOA diver, I primary donate and switch to my SS1. Note, that diver will never recieve my SS1. I will not allow them to and with it on a necklace theyll be more successful grabbing the reg from mouth. If you are ascending to the surface with them, remember to dump your bcd and that they do the same. You should be capable of doing this via SS1 or shoulder/kidney dump. I dont have any issues staying in trim, using my kidney dump while ascending, and dumping their inflator/other dumps if need be.

Case 2: primary reg failure, I have dove my SS1 many dives as my primary down to 100 ft and had no problems. When its properly tuned it breathes as well as my S600. Only two minor issues for me with ss1... (a) turning my head to the right from 60 to 90 degrees is impossible without pulling my mouth partially out of the reg. Can be fixed with a longer corrugated hose as my LP hose is long enough, but I dont like the extra clutter. Plus a single kick to helicopter spin me fixes this issue. (b) if Im diving back facing floor and head facing surface it breathes wet.

So if my primary fails, 1) switch to ss1, signal to buddy end dive and broken primary, 2) safety stop or what have you while staying extra close to buddy, 3) surface.

Case 3) ss1 free flow... this assumes it's not a minor leak but half to full free flow. 1) signal to buddy and disconnect LP QD hose, 2) reconnect and check if it's still a problem, 3) if it's still a problem disconnect and signal to buddy broken and to end dive, 4) safety stop if needed, 5) surface

Case 4) ss1 stuck auto inflating, if it's just a slow inflate then I'd just let my buddy know. If it's real bad where I can't maintain bouyancy, 1) hold my dump while disconnecting the LP hose, 2) signal to buddy my problem, 3) reconnect and see if it's still stuck, 4) if still stuck, signal buddy its broken and end dive, 5) I'd try to keep it connected until we get to the surface, but if I can't, I'll disconnect it, 6) surface as fast as safely possible if my ss1 is disconnected

Case 5) ss1 is disconnected and buddy has catastrophic failure, 1) buddy breathe off my primary and/or 2) CESA if needed

In summary, for me theres only two minor and one major edge cons. The minor con of OOA diver where I cant see 60-90 degrees to the right without kicking to rotate myself or I can't invert myself with my back towards the floor without breathing wet. Those arent really issues for me. The only real major con for me is specifically, broken ss1 that auto inflates so badly I need to disconnect it and before we reach the surface my buddy has a catastrophic failure and we need to buddy breathe. If they had the failure before I disconnect, it wouldn't be a problem. If my 2nd regulator wasnt integrated, then I'd still have two regs that can be breathe from and wouldnt need to end dive. For me, the chances of this is so low, I'll gladly use my SS1 every time

Anyways sorry for the long post, hope it helps

 

[Edward3c]

In the 1990s I dived with an AIR2 as the octo, that was until I was buddied with someone else with an AIR2. Near the end of the dive my SPG fell off. My buddy didn’t donate his primary, so I took the AIR2; now I had his buoyancy controls!

Before diving again I fitted a proper octopus as I didn’t want to be in the situation where someone else had my buoyancy controls. Additionally, the breathing quality of the AIR2 at depth wasn’t good.

 

[Curious_George]

just dazzling what stupid comments are made on SB

Look, most of this discussion is people stating their opinion. I find it laughable that best response you can come up with is that someone else’s comment is "stupid".

 

[scubadada]

Look, most of this discussion is people stating their opinion. I find it laughable that best response you can come up with is that someone else’s comment is "stupid".

That was not my comment at all. I successfully dived an Air2 for many years and found it a perfectly good 2nd. It does not drag on the bottom, as you seem to say. It has nothing to do with "breathing off your wing". Have you ever dived an Air2 or equivalent? I have the feeling that you are parroting much of what you have heard on SB, is that true, or are you speaking from your own experience? Your post was an embarrassment.

 

[johndiver999]

As others stated, it's all about your specific case. Diving environment, teammates, skill level, backup plan, etc...

My normal recreational setup diving with no overhead/deco ceiling, I have a primary donate 1st and an SS1 on a necklace.

Case 1: OOA diver, I primary donate and switch to my SS1. Note, that diver will never recieve my SS1. I will not allow them to and with it on a necklace theyll be more successful grabbing the reg from mouth. If you are ascending to the surface with them, remember to dump your bcd and that they do the same. You should be capable of doing this via SS1 or shoulder/kidney dump. I dont have any issues staying in trim, using my kidney dump while ascending, and dumping their inflator/other dumps if need be.

Case 2: primary reg failure, I have dove my SS1 many dives as my primary down to 100 ft and had no problems. When its properly tuned it breathes as well as my S600. Only two minor issues for me with ss1... (a) turning my head to the right from 60 to 90 degrees is impossible without pulling my mouth partially out of the reg. Can be fixed with a longer corrugated hose as my LP hose is long enough, but I dont like the extra clutter. Plus a single kick to helicopter spin me fixes this issue. (b) if Im diving back facing floor and head facing surface it breathes wet.

So if my primary fails, 1) switch to ss1, signal to buddy end dive and broken primary, 2) safety stop or what have you while staying extra close to buddy, 3) surface.

Case 3) ss1 free flow... this assumes it's not a minor leak but half to full free flow. 1) signal to buddy and disconnect LP QD hose, 2) reconnect and check if it's still a problem, 3) if it's still a problem disconnect and signal to buddy broken and to end dive, 4) safety stop if needed, 5) surface

Case 4) ss1 stuck auto inflating, if it's just a slow inflate then I'd just let my buddy know. If it's real bad where I can't maintain bouyancy, 1) hold my dump while disconnecting the LP hose, 2) signal to buddy my problem, 3) reconnect and see if it's still stuck, 4) if still stuck, signal buddy its broken and end dive, 5) I'd try to keep it connected until we get to the surface, but if I can't, I'll disconnect it, 6) surface as fast as safely possible if my ss1 is disconnected

Case 5) ss1 is disconnected and buddy has catastrophic failure, 1) buddy breathe off my primary and/or 2) CESA if needed

In summary, for me theres only two minor and one major edge cons. The minor con of OOA diver where I cant see 60-90 degrees to the right without kicking to rotate myself or I can't invert myself with my back towards the floor without breathing wet. Those arent really issues for me. The only real major con for me is specifically, broken ss1 that auto inflates so badly I need to disconnect it and before we reach the surface my buddy has a catastrophic failure and we need to buddy breathe. If they had the failure before I disconnect, it wouldn't be a problem. If my 2nd regulator wasnt integrated, then I'd still have two regs that can be breathe from and wouldnt need to end dive. For me, the chances of this is so low, I'll gladly use my SS1 every time

Anyways sorry for the long post, hope it helps

I have never seen an Air 2 on a necklace. I have never considered that, primarily because I suppose, to dump air, I normally raise the air 2 and press the deflate button. If it was constrained to my neck, this option would be lost.

How do you normally dump air?

It sounds like you have thought out the various emergency scenarios in good detail.

 

[johndiver999]

.... Unless you practice it, controlling your own buoyancy as your bcd gas expands is a bit of a challenge with the reg in your mouth, and your other arm linked with your OOA diver. You may need to remove the reg to lift the hose to vent, if you fall behind with expanding gas, and you're already task loaded from the OOA emergency. Can be a challenge to avoid corking, especially if your buddy is panicked and you have to also reach over to vent his bcd, along with your own.
Defenders will say that "it's just practice", and they're right. But it's a poorer performing second stage; it's prone to corrosion, and having my necklaced second right there after handing off my primary is just too easy.

In an air sharing, ascent scenario with a normal BC, a diver who does not use a pull dump, will need to locate the BC inflator (with their single free hand) and then raise it and press the deflate button to vent air.

With an Air 2, in an identical situation (with no alternative dump options being used or available) .. Then the diver has to grab the AIR 2 from their mouth, raise it, press the deflate button and simultaneously exhale for a duration of less than 4 seconds.

I really see VERY little difference in the two scenarios AND it could probably be effectively argued that it is easier to locate an AIR 2 (that is in your mouth) than a standard BC inflator that can be floating around somewhere. But I do completely agree, that a diver should practice ascending with their AIR 2 many, many times - until it becomes trivial.

I am surprised you reference poor performance with the AIr2. I recently started using an Atomic SS1 and I am somewhat embarrassed to say, it is tuned BETER than my primary second stage that is 30 years old- it breathes better at depth LOL. In any regard, the poor performance "issue" is addressed by tuning of the device.

Lastly, your comment about the sticky deflate button. That is 100% on point. It really seems to be a weakness in the design. It can make it difficult to orally inflate the BC, especially if you have weak hands or your strength is compromised by cold.

On the other hand, a Q-tip, vinegar and some silicone spray has kept my Air 2's working for years and years without replacing parts on the deflate mechanism.