stage tanks and OOA procedure

[mania]

OK I have a question concerning OOA procedures with stages.
Let's imagine 2 divers team. Gas switch. First diver switches to stage. shows OK. Now the second diver. switches and -let's imagine - the first stage of the regulator broke down (which is possible). So now two questions:
1. What is OOA procedure? You can't use the bottom gas and the long hose because it would be blocked by the stage hose running on top of the long hose and only half of it would be released.....
2. Both divers planned deco gas properly so there is enough for both of them. But how do you share the deco gas using really short stage tank hose?

I was looking for a detailed procedures of OOA when using stage tanks but couldn't find one....

Mania

 

[DIR-Atlanta]

1. What is OOA procedure? You can't use the bottom gas and the long hose because it would be blocked by the stage hose running on top of the long hose and only half of it would be released.....

To begin with, this is not an OOA situation, provided the team has managed its gas properly. The second diver should still have plenty of gas in the doubles, so what he would do is switch immediately to his necklace. Once everything was under control (stage bottle shut off and stowed, long hose unclipped, etc), then he goes back on his long hose and the team can begin to make their ascent/exit.

If the guy has a brain cramp and doesn't think to go to his backup, then his buddy donates the stage reg, and then goes to his backup - this is the prescribed procedure for all OOA situations (i.e. donate from the mouth and then go to the backup).

2. Both divers planned deco gas properly so there is enough for both of them. But how do you share the deco gas using really short stage tank hose?

I think you are confused on the difference between a stage tank and a deco tank. A stage tank normally contains the same mix that is in your doubles, and is used to extend bottom time (like to penetrate further into a cave or something). A deco tank usually contains a different mix from your back gas, and is used to facilitate off-gassing from whatever you breathed on the dive.

If it is a stage bottle that failed, then that does not affect the deco requirement, except possibly to shorten it (depends on where in the dive the failure occurred). You will still have all your deco gas in its own separate bottle, so no issues there.

For loss of deco gas, there is a procedure to get both team members safely to the surface. This is one of the things that is taught in GUE Tech 1.

I hope that clarifies things. If not, then feel free to ask more questions.

 

[ScubaMilo]

My response would be donate what I'm breathing(deco botttle) and go back to back gas.
There would be no obstruction of the long hose at this point.(if needed)
my buddy and I would then alternate breathing from the deco bottle extend stops to
1 1/2 times the normal stop.(not buddy breathing)
So I would breathe deco gas at first stop he would breathe back gas.
Next stop we switch me back gas him deco gas.
Back and forth, face to face until we reach our next switch or the surface which ever comes next.
Hope this is what you were asking for,
I am assuming we are talking about a deco switch.
Milo

 

[limeyx]

OK I have a question concerning OOA procedures with stages.
Let's imagine 2 divers team. Gas switch. First diver switches to stage. shows OK. Now the second diver. switches and -let's imagine - the first stage of the regulator broke down (which is possible). So now two questions:
1. What is OOA procedure? You can't use the bottom gas and the long hose because it would be blocked by the stage hose running on top of the long hose and only half of it would be released.....
2. Both divers planned deco gas properly so there is enough for both of them. But how do you share the deco gas using really short stage tank hose?

I was looking for a detailed procedures of OOA when using stage tanks but couldn't find one....

Mania

1) This should be covered in your accelerated deco/tech training classes.

Assuming you are just curious about how "other" people do it:

- before you put the stage reg in your mouth, you are going to pressurize the first stage and purge the second. So in this case you would know before even putting the deco reg behind your head that it was busted.

- Even if you did put the deco reg behind your head to breathe it, you have plenty of room to keep the long hose in. You can also just stow the deco reg back on the tank.
Worst case, you can go to your backup 2nd stage under your chin.

- the 40" hose is shareable. I would extend the stops by 50% with one diver taking the stage reg for 1/2 the extended stop time, the other on back gas (no buddy breathing) and then switch reg around. Then ascend to the next shallower stop etc.


I think your post is relating to a diver going to his deco bottle, seeing it is broken and signaling OOA.

First
1) The diver is NOT OOA -- he just goes to his own long hose or necklace reg
2) if he does signal OOA (forgets he has a long hose) -- save the lecture for after the dive and donate your stage (it is long enough, you may need to get in a little close)
3) once you have fixed the "emergency" either notify the other diver that he has two perfectly good working regs within 1 foot of his mouth.

If the other diver is really panicked, you now deploy your own long hose. you have plenty of time to untangle/fully deploy it. Then you give the other diver your long hose and get the stage reg back and share it as above.

GUE/DIR training is always to donate whatever reg is in your mouth (back gas, bottom stage, deco stage) because
- you know it is working
- you know it is the right gas for the depth you are at
- you know right where it is and can get to it quickly
- it should always be deployable quickly and easily.


But DONT LEARN TO DECO DIVE ON THE INTERNET!! Take the right training.

 

[mania]

OK
Yes - I was talking about deco switch.
Yes I had some training (I'm Adv. Nitrox IANTD).

And now - I'm trying to imagine the situation - which after all is not impossible - thet diver 2 lost all his gas. Both - the bottom one and the deco one.
If the dive was properly planned diver 1 has enough gas to get both of them out.
Now what is the procedure.

My point was - the routing of hoses in this case in fact blockes the long hose. So diver 1 has to either handle the stage tank (with deco gas) to diver 2 and switch to bottom gas. Or has to unroute the long hose (which means talking regulator out, maybe switching to his backup one, then get the long hose from under the stage one, handle the long hose and get back to deco gas). The second situation for a panicked diver that has no gas at all is way too long....
And it's easy of there is only one stage tank. What if we have two or more????

Still no clear procedure. We have clear procedure - step by step for an easy OOG situation but I can't find a step by step procedure for such situation.

limeyx - because I have some trainig in deco dives I'm the last one to learn it from internet. But was trying to find procedures for a situation I was practicing lately....

Mania

 

[DIR-Atlanta]

Still no clear procedure. We have clear procedure - step by step for an easy OOG situation but I can't find a step by step procedure for such situation.

There is a very clear procedure - limeyx and I both described it. In an OOG situation, you always donate the reg in your mouth and go to the backup on the necklace. It doesn't matter where you are in the dive, how many bottles you are carrying, or how much deco gas you have left. You always donate from the mouth and switch to your backup.

Once the diver has gas, then you (and your team) figure out what to do next. That will be situationally dependent, based on where you are in the dive and what team resources are (or may become) available.

because I have some trainig in deco dives I'm the last one to learn it from internet. But was trying to find procedures for a situation I was practicing lately....

I'm curious - when you took your Adv Nitrox course (which is a deco course), what did your instructor say about handling an OOG situation at deco?

 

[mania]

here is what I had during the course - exactly OOG at deco
http://www.scubaboard.com/showthread.php?t=106603&highlight=advanced+nitrox

Anyway thanks all
Mania

 

[*Floater*]

For loss of deco gas, there is a procedure to get both team members safely to the surface. This is one of the things that is taught in GUE Tech 1.

I hope that clarifies things. If not, then feel free to ask more questions.

What's the procedure?

In particular, if you have 2 divers each with an AL40 of EAN50 for deco and plenty of backgas, but one of them loses the deco gas, then would you share the remaining deco gas (evenly?) or would the guy who lost it deco on backgas supposing he had enough? And if you share, then do you have one guy breathe half the bottle first, and then give the result to the second guy, or do you pass it back and forth every 5 min or every deco stop or something else? And also would you hand the bottle off to the other guy once you are done or between switches, or just hand the reg for him to breathe?

For purposes of this question let's assume there's no O2 bottle hanging from the boat or available to be dropped down and that the lost gas is completely lost (it leaked out, no reg switch or fix possible). And also assume backgas breaks aren't needed.

Edit: I added some questions.

 

[onfloat]

Double the deco. Your rock bottom in your back gas should cover a loss of deco gas for one AL40 of EAN50

 

[*Floater*]

Double the deco. Your rock bottom in your back gas should cover a loss of deco gas for one AL40 of EAN50

Okay so this would be the main DIR solution I take it.

Let's say your buddy only needs 30 cu.ft. of that AL40 to finish his deco. Should he then pass the rest to you so that you can both get out of the water a little faster or a little cleaner? And if yes, then should he pass just the reg or the whole bottle?