Identifying Stages By Feel

[W W Meixner]

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.

JG...

Thank you for sourcing the standard...I hope I never have to do this...but depending on the number of cylinders...less is always better than more...there is still going to have to be distinctive differences to be able to ''feel'' which cylinder is which...

Referencing d....

To make things difficult...how about four AL 80's...all with SP MK 17's...and G250's/identical SPG's...configured the same...with identically configured harness assemblies...nothing distinctively different...

Challenging...if not impossible if there are no distinctive differences...that can be easily determined/identified by feel...

I wonder what the instructor...who is instructing on this standard does to ensure cylinder retrieval is being performed correctly...

Warren...

 

[rjack321]

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.

I would honestly find another agency that isnt having you remove and replace chakras but here you go:

Use a left and a right valve and sidemount them, by typical convention the left is deep BO, the right would be something like 50%. Knob goes out, if the reg is facing down (or up if you fancy that) then you know its on the correct side and *in theory* what's inside. Also orientation of the cam band strap on the bottom tells you which side it belong on.
Need more useless drilling? Add an al40. You can tell its small.
More? Add a conventionally rigged stage bottle (2 clips, rubber hose between them) with a 40" hose

4 bottles, all unique. Chakra away.

 

[rjack321]

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?

Or you could just plug in the BOV to a single large offboard with a QC6 or another high flow connector and be done with it.
I dont know what it is in the UK that has you all using onboard dil as a BOV feed. We don't do that over here. Maybe because at 100m you get about 1 breath from what's left of your onboard 3L dil bottle, less from a 2L. At that point you need another reg to breathe anyway and you have no wing now - so its going to be long long ascent.

 

[JohnnyC]

Yep, must be a new thing in the standards. Still stupid af.

 

[Gareth J]

Or you could just plug in the BOV to a single large offboard with a QC6 or another high flow connector and be done with it.
I dont know what it is in the UK that has you all using onboard dil as a BOV feed. We don't do that over here. Maybe because at 100m you get about 1 breath from what's left of your onboard 3L dil bottle, less from a 2L. At that point you need another reg to breathe anyway and you have no wing now - so its going to be long long ascent.

You are correct.
The last few years, most of my diving has been within recreational limits, so using the in board is less of an issue.
Until recently, I didn't have a BOV, so it was all a bit academic, I was reliant on the bailout stage and its regulator.

 

[Jaydubya]

I recall having to do this in OC cave class but don't recall having to do it in rebreather classes, cave or otherwise. But maybe we did -- it's been years. In OC cave class I engraved the rubber "handle" on the stage bottles with the same pattern that I use for my cookies, spools, and reels. Telling the bottles apart was easy since I had an 80 and a 40.