Air 2 free flow while scootering

[chris kippax]

Hi guys
Yesterday the wife and I went for a dive at the Gold Coast Seaway. A fairly routine dive site that we had both dived previously, on this dive though we were to be using 2 Apollo AV-1 scooters for the first time. We started the dive very slowly and we're just slowly familiarising ourselves with the scooters. We stayed close and observed each other and everything looked OK. I did notice that when the wife was propelling forward there were some bubbles/turbulence coming from here prop. After 26 minutes into the dive she signalled to me that she was OOA. I deployed my backup and we just took a minute too stabilise our breathing and take stock of the situation. We were about 200 meters from the exit in a heavily used boating channel. So the decision was made too tow the wife while air sharing, it was interesting but quite easy. I powered my scooter while she held my tank valve and let her scooter hang behind. We made it too the exit with about 70bar to spare and exited with minimal drama. We checked over all her gear and no leaks/faults were found. Upon reflection the bubbles I saw were a steady free flow from her airsource 3 aqualung Octo inflator.
Is there any way she can prevent this from happening as I recommend she gets a quality reg as a back up and go to a standard inflator, but she is quite attached to her air 3. Thanks Chris

 

[g1138]

Hard to say without having it on the bench.
If it's tuned very finely, you could tighten it down. This would increase it's cracking pressure and possibly breathing resistance depending on how the internals are made.

Tweaking your Air 2 slightly in how it hangs could help too. Once you catch any reg in the right downstream of water flow you can get it to free flow; Venturi then takes over and it keeps going.
If your wife had it draped on her arm, the prop wash would have surely been flowing into the purge, which at the right speed can cause a free flow.

I got my octo to free flow recently while chasing a fish. I quickly jostle and twisted it differently in it's bungee loop and it stopped. It's a traditional rec setup, not bungee backup; mounted above the right hip.

 

[Shiprat]

Both my wife and I dive with AV-1's and we both have Airsource 2's as our safe seconds. Free flowing Airsources has never been an issue for either of us. I would guess you can simply tighten the tuning in your wife's if you already done so. Be careful not to let the Airsource get into the propeller intake when riding the scooter. That was an issue for me early on but I've since clipped off my airsource to keep it from dangling freely.

 

[andrewy]

thats why they inventedeth DIR your second should be really a lower performer like scubapro m50/r109
and stay on your neck away from the prop. seriously makes things much simpler.

 

[syntaxerrorsix]

thats why they inventedeth DIR your second should be really a lower performer like scubapro m50/r109
and stay on your neck away from the prop. seriously makes things much simpler.

There is never a good reason to use a low performing regulator. Especially if you are are wearing it on a necklace and are going to be the one breathing from it. That just doesn't pass the common sense test.

Proper posture, streamlined, secure gear will prevent water pressure from pressing on the 2nd stage diaphragm.

 

[PfcAJ]

An unbalanced 2nd stage is the move for the necklaced backup regulator. Its not as sensitive as a balanced adjustable but still breaths just fine. You can 'detune' an adjustable reg with the knob, but all you're doing is increasing pressure on the seat and increasing wear so that when you do move the adjustment knob out it'll leak.

There is never a good reason to use a low performing regulator. Especially if you are are wearing it on a necklace and are going to be the one breathing from it. That just doesn't pass the common sense test.

Proper posture, streamlined, secure gear will prevent water pressure from pressing on the 2nd stage diaphragm.

 

[syntaxerrorsix]

An unbalanced 2nd stage is the move for the necklaced backup regulator. Its not as sensitive as a balanced adjustable but still breaths just fine. You can 'detune' an adjustable reg with the knob, but all you're doing is increasing pressure on the seat and increasing wear so that when you do move the adjustment knob out it'll leak.

It only needs to be adjusted when you plan to breathe off it. I've not noted any significant wear between it or my primary when comparing the HP seat. To each their own. If I'm on my backup it's likely my work load has just increased. I'll spring for the $4 dollar seat every couple years for a better breathing reg.

ETA I understand it's a DIR thing. Not trying to undermine anyone's training or opinion on the matter.

 

[digdug87]

More than likely the speed of the scooter was causing lower pressure outside of the regulator, than inside. This in turn caused the regulator to open, just like it is designed to do. You may want to look for cover or plug for the mouth piece of regulator.

 

[andrewy]

There is never a good reason to use a low performing regulator. Especially if you are are wearing it on a necklace and are going to be the one breathing from it. That just doesn't pass the common sense test.

Proper posture, streamlined, secure gear will prevent water pressure from pressing on the 2nd stage diaphragm.

I said lower performer not low performer . as for instance my G250 is balanced too loose and will be triggered by water flow while scootering if used as secondary. Position, trim or securing gear has nothing to do with it. water flows front to back . for necklace i use M50, harder to get now, but bullet proof when i need to donate my primary and will not freeze.
I am sure you can de-tune anything not to free flow, but why bother. again this is just my 2 cents im sure others have different opinions.

 

[redacted]

An unbalanced 2nd stage is the move for the necklaced backup regulator. Its not as sensitive as a balanced adjustable but still breaths just fine. You can 'detune' an adjustable reg with the knob, but all you're doing is increasing pressure on the seat and increasing wear so that when you do move the adjustment knob out it'll leak.

Balanced vs unbalanced is not a variable in the sensetivity of a 2nd stage (propensity to freeflow). It is much more regulated by case, cover, diaphragm, lever, and poppet design; and proper adjustment and tuning. For 2nds t6hat do not have a seat saver feature, wear (setting) of the seat occurs almost entirely when the reg is not in use. When the reg is under pressure force of the seat against the orifice is just enough to stop the flow of gas. That force is the same whether it is provided entirely by a mechanical spring or by a combintion od mechanical and pneumatic spring. An adjustable 2nd, like a 109 or 156, allowa an alternate 2nd to be detuned a bit during the dive to resist the effects of current, surge, or scootering.