Identifying Stages By Feel

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These are some seriously stupid standards. Do I have to unplug the Al80's QC6 that feeds my BOV and drop this cylinder in the silt too?
 
These are some seriously stupid standards. Do I have to unplug the Al80's QC6 that feeds my BOV and drop this cylinder in the silt too?

This is one of the issues I considered, and have currently settled on the BOV being connected to the inboard DIL. Despite the low volume of available gas inboard.

My 'best' solution currently, would be to have a switching block [1] that, by default connects everything to the inboard DIL, allowing me to plug in the off board bailout.
The consideration then, is do you connect the off board bailout to the switch block, or plan to do it in water? Can you easily disconnect in water if required, and reconnect?
In truth, for most recreational diving you wouldn't need to plug in before entering the water. On deeper, high risk dive you would enter the water with everything connected.
You would also need to consider the additional task loading / practice drills to become instinctive and skilled in its operation. Maintenance, considerations, kit configuration issues with other team divers.

Strictly speaking, we are diverging from the OP. But the issue of bailout, AAS regulators, BOV, are all interconnected.
One argument is that you have one setup for OC and one for CC divers, and never the two shall meet, i.e. a bit GUE - you only dive with other GUE divers. Whilst for some that might work, I think for the majority it doesn't.
Certainly for me, it wouldn't. I dive with a wide variety of divers, including new divers, and very experienced divers (even GUE [2]).
I do a lot of club diving, but also, a lot of turn up and dive, or 'guesting' with other groups.

Gareth

[1] There is an issue with switch blocks. Incorrect operation, incorrect switch position. Additional failure points. So in itself it's a whole new assessment. At what depth is your switch block restricting gas flow (when you have elevated breathing rates due to CO2)?
[2] Perhaps they are not GUE if they are diving with me?
 
Different manufacturer seconds stages is lame. What happens when you have to swap one on the surface before a dive, your whole "OMGICAN'TSEETHANKGODFORPOSEIDON" goes out the window. Not to mention needing to source a bazillion different parts kits.

ETA: I am not a GUE. I like other colors beside red drysuits. That doesn't mean things like reasonable bailout volumes easily accessible isn't a smart thing to do.
 
These are some seriously stupid standards. Do I have to unplug the Al80's QC6 that feeds my BOV and drop this cylinder in the silt too?

Yes, it comes right after the lights out drysuit removal and replacement drill.

No, and it is not like the Blue Grotto death either. It's a silly confined water thing, emphasis on silly, that involves identifying cylinders by feel. You can do it in the damn pool I suppose. The only relevance of the standard is that it prompted me to ask if there was a "protocol" for cylinder identification by feel. That answer seems to be no.
 
Can you post the standards? Granted the copies I have are all several years old, but the only bailout drills that involve zero vis is simply a switch to a bailout gas, nothing about identifying cylinders, etc. That's not quite the same thing as dropping a bunch of tanks, swimming up to them randomly, and identifying them. I'd be curious to see how that standard is written.
 
For the comment that it isn't the same as the death in Blue Grotto there you had a student breathing a gas that they couldn't verify the po2. Here the same thing could happen if the wrong cylinder was selected and due to not being able to read the mod or mix% they could possibly get on the wrong mix. Doesn't it all boil down to don't breathe a mix that you don't know the po2? On a breather or OC?
 
For the comment that it isn't the same as the death in Blue Grotto there you had a student breathing a gas that they couldn't verify the po2. Here the same thing could happen if the wrong cylinder was selected and due to not being able to read the mod or mix% they could possibly get on the wrong mix. Doesn't it all boil down to don't breathe a mix that you don't know the po2? On a breather or OC?

Yes and No.

On OC you choose when to switch to a stage, it is not an emergency procedure. Yes, delaying a switch changes the decompression profile. This is less of a problem now than 15 years ago, we use mixed gas computers, then it was hard tables. A computer can give you a new schedule on the fly. Your only risk of delaying a switch to travel or deco gas is the effect on your available gas, and you shouldn't have such a tight gas plan [1].

On CC a switch to a stage cylinder (bailout and deco gas), is not part of the normal dive plan. It is part of the emergency plan. If you need to switch to bailout, that is an immediate and critical requirement that can't be delayed. A switch to OC from CC is the must sub-optimal action you can take [2].
It's an action you may need to take now, immediately, no delay. You are switching because whatever is in the loop is trying to kill you now, you no longer have a safe breathing gas.

Gareth

[1] Granted a loss of one of your gases will already have put pressure on your available gases.
[2] Yes - basic CC qualification is "if in doubt. bailout", advanced courses are about trying to stay on the loop.
 
The point of the exercise, as I understand it, is to avoid precisely the scenario you identify - under supervision, and it can be done in confined water. And, there is no requirement that you breathe off the cylinders immediately. You just have to demonstrate you can identify by feel and reattach to the correct sides. In a class setting, having completed the drill, you would be free to visually confirm MOD before having to actually bail out. As I said, the drill is dumb and takes 10 seconds. So, I really don't think that it is a Blue Grotto sort of scenario unless the instructor was dogpiling a bunch of stuff on top of the standard.

It just caused me to ask whether this was a "thing" and there was a protocol for the cylinder identification. Given that some folks insist on a standardized steak knife, it wouldn't have surprised me if this issue had been addressed.

@JohnnyC, the actual standard in rev 21.0.1 of IANTD Trimix (which may or may not be current, I just found it online). The part dealing with rebreathers as opposed to OC, reads, in part:

16. (RB) Remove and Recovery of stage cylinders while swimming:
a. Follow a means of reference (pool wall, guide line, ship railing, etc.) with eyes closed
b. Remove stage cylinders
c. Swim a distance of at least 15 feet (4.6 meters) reverse direction
d. Return to stage cylinders and replace them on correct sides, identifying each cylinder by feel.
 

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