Comparative Debate on AAS Configuration Options

[DevonDiver]

I'm starting this thread as an off-shoot to a current discussion on AIRII systems. Most of the debates about any singular AAS configuration seem to disintegrate into a 'my system is better than yours' arguement. For the sake of clarity, I thought it might be interesting to compare and contrast the percieved pros and cons of varied AAS configurations, in a logical and side-by-side manner.

I've included a poll, so that readers can get an understanding of the relative popularity of these configurations amongst the participants (not thinking for a moment that SB membership accurately represents the true state of the diving community as a whole).

So, to get the ball rolling, I am listing 3 major configuration alternatives, that encompass the primary methods used for air-sharing. Feel free to add to the pros, cons and potential failures... however, lets try not to be biased or resort into a non-productive justification of our favoured configuration. Let's try to be critical, but fair.


'Standard' Octopus - secondary donation

This is the typical configuration, as demonstrated in most entry-level scuba manuals/videos etc. The diver has a regular length primary regulator and a donated alternate air source that is secured by a pull-release attachment, within the 'triangle' formed by their chin and bottom corners of their rib cage. Typically, the AAS hose will be slightly longer than the primary hose. The diver donates the AAS, maintaining the primary regulator for their own use when air-sharing.

WHY DIVERS USE IT
That is what they used on their OW course
That is how their local dive shop sells regulators
Don't need any specialized configuration
They rent it, and that is how it comes

PROs
The 'rescuer' does not lose/change their air-source during the initial stages of air-sharing, when stress is highest.
Many/most divers are taught this method during entry-level courses
Longer AAS hose allows a reduction in forced proximity by air-sharing divers
Relatively intuitive and fool-proof procedure to obtain air and ascend

CONs
It requires a secondary, dedicated, AAS regulator and hose (less streamlining)
Stowage error can lead to obstruction of the AAS at a critical time
Some divers allow the AAS to dangle, where it can get broken or filled with silt etc
AAS is not guaranteed to work at the point of air-sharing

WHERE IT CAN ALL GO WRONG
Divers might not stow the AAS properly (let it hang/stick it in a pocket etc) making it unavailable immediately in an emergency
Victim may 'steal' the primary, in which case the AAS is not immediately available close to the rescuers mouth
Improper buddy checks will not identify any failures in the AAS until it is actually needed


'Long Hose' - Primary donation



This is often labelled as a 'DIR', 'Hogarthian' or 'Tech' approach to air-sharing, due to its popularity with technical and overhead environment divers. As interest and involvement in technical/cave and advanced wreck diving grows, this practice (like many) has increasingly migrated into the sphere of recreational/open water diving. The configuration consists of a short length (22-24") hose attached to the AAS, which is bungeed in a necklace around the divers neck. The AAS may be permanently attached to the necklace (tie-wraps) or can remain deployable (mouthpiece through a loop in the necklace). The primary air-source is held on a longer hose (5-7') that is secured/routed in a steamlined manner. Typical primary hose routing is either to wrap it around the body/neck, or to bungee it to the cylinder. In an out-of-air (OOA) emergency, the donor provides his long-hose primary regulator to the victim and immediately secures his own AAS to breath from during ascent.

WHY DIVERS USE IT
Wish to utilise percieved 'best practice' procedures from advanced diving development
Operating in a restricted environment
Prefer to maintain a standard configuration in all diving environments (and use long hose for advanced diving activities)
Believe that it is more streamlined
Capacity to ascend without forced close proximity

PROs
Very long hose prevents any forced proximity between air-sharing divers, allowing a more normal, relaxed ascent
Very long hose provides capacity to air-share in restricted environments (one diver behind the other)
Necklace stowed secondary is immediately available to the diver (with practice, can even be accessed without hands)
Victim is assured that the donated regulator is working
AAS will not dangle

CONs
Diver requires training to properly stow and deploy the long hose
Rescuer has to change air-sources whilst effecting a rescue to an OOA diver
Many divers are not familiar with long-hose configurations and related procedures

WHERE IT CAN ALL GO WRONG
Victim may instinctively attempt to secure the AAS, which has a very short hose and/or may be permanently attached to the necklace
Donor may trap/entangle the long hose, preventing effective donation


Inline Octopus (AIRII) - Primary donation


This configuration utilises an 'in-line' or combined low-pressure inflator (LPI) and alternate air-source (AAS) in one unit. The unit is fed by a single, dedicated hose that feeds the LPI and provides breathing air.

WHY DIVERS USE IT
Seek to minimalize/streamline/reduce bulk and/or weight in their configuration
One less hose

PROs
Reduces one hose from the overal regulator configuration
AAS does not require a specific attachment method (held by the LPI hose)
Victim is assured that the donated reg is working

CONs
Combined LPI/AAS are heavier than an LPI alone and, thus, can dangle below the diver (fill with silt, get damaged or generally annoy)
AAS hose length dictated by LPI hose length - can be too short to allow a diver full head/neck mobility
More complex, task loaded operation to breath from AAS whilst operating LPI to inflate/deflate BCD
Less intuitive for both the donor and reciever
Requires extended length primary hose, which may not be routed in a streamlined, entanglement aware manner
LPI/AAS can become tangled in BCD straps, snorkel etc, due to location and being 'free-hanging'
Dedicated hose required for LPI/AAS, which may not be easily replaceable if it fails or diver uses rental regs

WHERE IT CAN ALL GO WRONG
Donor may not have a long/extended length primary hose, thus forcing close proximity (stress factor) during emergency ascent
Donor might struggle to control buoyancy on ascent, causing sinking and/or uncontrolled ascent
AAS/LPI might become entangled on the donors BCD and not immediately available
Victim might be stressed into panic when they search for, and cannot locate, a traditional AAS (increasing risk of primary snatch)

 

[DaleC]

To this list I will add two other options; single reg on backgas + single reg on pony (this could also include BM indies and SM rigs), and single reg/no octo. For purposes of equipment analysis, I would ascribe the same level/lack of skill to all donors and recipients.

The configurations:

1. Octo kept in golden triangle
2. Octo kept on bungied short hose
3. Octo inline with BC inflator
4. Octo on pony/seperate tank
5. No octo

Observations:

Rigs 2, 3, and 5 require primary donation.
Rigs 2, 3, and 5 require additional training in regards to the donor (above that provided in most basic OW courses).
Rig 5 requires additional training in regards to donor and recipient.
Rigs 2, 3 and 4 have easy to locate octos from the donors POV.
Rigs 1, 2, 3, 4 and 5 all have (potentially) difficult to find octos from the recipients POV.
Rigs 1 and 4 have the potential for the octo to come loose from it's attachment point.
Rigs 2, 4 (and perhaps 3) allow for workable distance between donor and recipient.
Rigs 2 and 3 have the potential for the donors functional impairment if the wrong reg is taken.

My personal perspectives (YMMV):

1. I have come to dislike this system immensely as the octo location is too vague to be reliable and octo keepers vary greatly in their ability to actually hold and/or release the octo. The primary can be hard to recover if lost. I also find that people who use this configuration tend not to breath their octo's routinely predive due to the hassle of deploying and restowing.

2. I like this system a lot as the octo is always in an easily accessable location (under the chin) and the primary is easy to recover if lost. Primary donation allows the donor to control the event. Predive tests are easy. The one downside is that, if the recipient somehow manages to take the octo instead of the primary, the shorthose is inadequate and could result in loss of situational control for the donor. There is no denying that one reg is not configured for the recipients use.

3. I like this system for the above stated reasons (though its primary can be hard to locate if standard length and lost) It's limitations also being the same at the recreational level. For more demanding dives I can see the combination of inflator and octo becoming a limiting factor (complexity, one failure resulting in two losses) but will admit to not using one in that manner.

4. Another very good system IMO with no drawbacks (I don't consider slinging a tank a drawback) that I can see and the added benefit of providing a completely redundant air source to the donor. This is my main system when diving deep solo or with others while using an expermental/unknown primary rig.

5. A system that is perfectly valid but has it's place only when moderately deep solo or in the company of other divers trained in buddy breathing. It requires a skillset that modern trained divers simply do not possess.

 

[knowone]

All my gear and configurations are different and all over the place
The closest to standardisation is a secondary clipped to a shoulder D ring
I build and configure all my gear
All my gear works
It never sees the inside of a shop that works on these things
I use long hoses on primarys and secondarys
I attempt to be aware of potential problems with other divers regarding OOA
I have never been OOA unless there is a reasonable situation to be OOA in
I will NEVER donate my primary
Drills are drills
My configuration and attitude changes depending on the dive and divers.
Any of the above may change due to forseen or unforseen circumstances

I WILL NEVER EVER DONATE MY PRIMARY.

Unless a primary is all I have?

 

[vladimir]

I use the bungied secondary and primary on a 40" hose routed under my arm, based on my brief tech training and the ScubaBoard's influence. I could probably use Dale's option 5, "no octo," because I'll probably never donate gas. I never have, in almost 800 dives, including a rescue of a drowning diver. I have a decent SAC--about .5--but when I do have buddies they're usually half my size. We're usually in warm clear water less than 20 meters deep, almost always less than 30 meters deep. But, if the improbable or unusual should happen, it will be good to have an easily deployed gas source for the unlucky bastard.

 

[beanojones]

You, uh, skipped one. Air II and long hose.

Or Shadow plus and Maximus, etc. They got it right the very first time. 40" under arm reg with a inline reg on the standard inflator hose. None of the drawbacks: Standard hose, etc.

 

[DevonDiver]

None of the drawbacks: Standard hose, etc.

They all have drawbacks. This isn't about pimping our chosen configurations... it's about pros and cons. I'd love to hear more about your configuration, but I don't believe for a second that anything mentioned in this thread is ideal, for everyone, on every dive. Any chance of some balance and detail?

 

[ajduplessis]

At the end of the day there is no right or wrong option. You have to evaluate every option available add decide what's the best for you.

If I had to enforce/train someone it would be the long hose, it is the best option for all diving conditions and environments. :gun:

 

[BDSC]

I'm a little curious about something. You listed as a "Con" on the AIR II set-up the following:

"Requires extended length primary hose, which may not be routed in a streamlined, entanglement aware manner"

So how is this a "CON" for this set-up and not a "Con" for the "Long Hose Primary Donation"? Couldn't you just as easily say the same for both? If the person with a LHPD has his long hose routed properly, couldn't the guy with the AIR II system have his routed properly as well? If the guy with the AIR II doesn't have his properly routed, could the guy with the LHPD not have his routed properly?

You also list as a "Con" for the AIR II system the following:

"Combined LPI/AAS are heavier than an LPI alone and, thus, can dangle below the diver (fill with silt, get damaged or generally annoy)"

and:

"LPI/AAS can become tangled in BCD straps, snorkel etc, due to location and being 'free-hanging'"

But if you simply clip it to the BC wouldn't that take care of these?

I have an AIR II and mine maybe hangs down a couple of inches from the BC at most. You'd have to be crawling on the bottom for it to fill with sand.

I fully admit that the AIR II in some diving situations may not be ideal like cave diving but if you are going to list something as a "Con", make it a real life diving situation and not something that has an easy fix to it.


Another possible "Pro" that I have seen listed in other threads for the AIR II is that because you are likely to use your inflator during the dive, you instinctively know right where it is, and because of that "memory effect" you will be able to quickly reach for it without fumbling around trying to find your octo. So if that is indeed a "pro" for the AIR II, would it then be a 'Con" for the std. rig to have to fumble around trying to find your octo?

 

[waterpirate]

I do not think there will be any fair or balanced decisions born out here. IMHO the choices are made and gear configured by the enviroment in which you dive, and how the person who trained you educated you. Enviroment dictates the gear. Standard gear assumes a standard enviroment and that is the flaw. There is no standard enviroment, so no one configuration would fit.

 

[Splitlip]

You, uh, skipped one. Air II and long hose.

Or Shadow plus and Maximus, etc. They got it right the very first time. 40" under arm reg with a inline reg on the standard inflator hose. None of the drawbacks: Standard hose, etc.

I did this for a long time. I had my Air II (actually Atomic SS1) on a 19" corrugated hose with a BPW. I wore a console accross my chest and tucked the infaltor behind that.
My rig morphed over time. I am essentially diving a HOG rig today. I have a D-ring on my right hip for my lobster bag and such. My long hose is 5'-6" long and routes directly under my right arm, across my chest to my left shoulder, behind my neck and over my right shoulder to my mouth.

More on the 5-6 hose. I liked th 40" hose, but when out of my mouth on deck, it was too long. I used a 5 ft hose for a while, but that was "tight". When I got it to where I could move my head correctly, the hose seemed to conflict with my right shoulder D-ring and my necklaced alternate. Somebody here suggested I try a 6ft hose. I did. Better but then it was too long. So I had a 5-6 hose made. Just right.

A plus to routing behind the neck; unless I am head down while upside down, it is impossible to lose the 2nd stage.