Is it OK to turn off O2 in Rebreather Training?

[JohnnyC]

Only to the people I don’t like.
Some people call it abrasive, I call it an intolerance and impatience with stupidity.

But I wasn’t trying to be abrasive here. I didn’t post the reason publicly because potential students come from this board, and I didn’t want him to look bad to a potential student.

I have had conversations through PM with him and a few others that didn’t understand. Seriously, it’s not your fault as a new rebreather diver if you don’t know this. I think it’s your instructors fault. It’s simple concepts that aren’t being explained or understood.

I’ll give you another that I hear ALL THE TIME.

If you’re in the ocean and run completely out of DIL, what do you have to do? The instructor’s answer all the time is BAIL OUT. That’s the wrong answer.

The purpose of DIL is make up gas. It’s gas to get you to the bottom. You can’t breathe pure oxygen, so you need something to get you there. But, you’re on the bottom in 200’ of water and your DIL is gone. Do you need to bailout? NO! You have to abort the dive, but as you start ascending your loop volume is increasing and your PPO2 is plummeting. So you add oxygen.

I’ve co-taught with half dozen instructors who overlook this, and when I lay it out just like that they go, “oh yeah, that’s right”. I’d much rather be on the loop than on open circuit if it can be helped. Especially in a cave.

I'm not sure how much of that is overlooking the obvious, and how much is agency standards requiring bailout being the first option to deal with anything so that's their default response. I know when I did my Meg MOD1, everything was a bailout scenario. However, my MOD1 instructor was also an exploration cave diver and expressed his displeasure at this concept, and thus saw fit to teach multiple failure responses.

A good friend of mine will respond with "bail out" to every failure scenario, appended with a wink. He then goes on to explain every other facet of failure management to his students.

It seems that SCR, open loop, feathering O2, etc. have all been relegated to conversational aspects only for most MOD1 courses.

 

[Superlyte27]

I'm not sure how much of that is overlooking the obvious, and how much is agency standards requiring bailout being the first option to deal with anything so that's their default response. I know when I did my Meg MOD1, everything was a bailout scenario. However, my MOD1 instructor was also an exploration cave diver and expressed his displeasure at this concept, and thus saw fit to teach multiple failure responses.

A good friend of mine will respond with "bail out" to every failure scenario, appended with a wink. He then goes on to explain every other facet of failure management to his students.

It seems that SCR, open loop, feathering O2, etc. have all been relegated to conversational aspects only for most MOD1 courses.

I get that, and I do teach that when in doubt, bailout. Especially at MOD1. But as you can imagine, at 200’, we’re not teaching mod 1, nor are we at the back of a cave.

 

[Pavao]

Only to the people I don’t like.
Some people call it abrasive, I call it an intolerance and impatience with stupidity.

But I wasn’t trying to be abrasive here. I didn’t post the reason publicly because potential students come from this board, and I didn’t want him to look bad to a potential student.

I have had conversations through PM with him and a few others that didn’t understand. Seriously, it’s not your fault as a new rebreather diver if you don’t know this. I think it’s your instructors fault. It’s simple concepts that aren’t being explained or understood.

I’ll give you another that I hear ALL THE TIME.

If you’re in the ocean and run completely out of DIL, what do you have to do? The instructor’s answer all the time is BAIL OUT. That’s the wrong answer.

The purpose of DIL is make up gas. It’s gas to get you to the bottom. You can’t breathe pure oxygen, so you need something to get you there. But, you’re on the bottom in 200’ of water and your DIL is gone. Do you need to bailout? NO! You have to abort the dive, but as you start ascending your loop volume is increasing and your PPO2 is plummeting. So you add oxygen.

I’ve co-taught with half dozen instructors who overlook this, and when I lay it out just like that they go, “oh yeah, that’s right”. I’d much rather be on the loop than on open circuit if it can be helped. Especially in a cave.

Only to the people I don’t like.
Some people call it abrasive, I call it an intolerance and impatience with stupidity.

But I wasn’t trying to be abrasive here. I didn’t post the reason publicly because potential students come from this board, and I didn’t want him to look bad to a potential student.

I have had conversations through PM with him and a few others that didn’t understand. Seriously, it’s not your fault as a new rebreather diver if you don’t know this. I think it’s your instructors fault. It’s simple concepts that aren’t being explained or understood.

I’ll give you another that I hear ALL THE TIME.

If you’re in the ocean and run completely out of DIL, what do you have to do? The instructor’s answer all the time is BAIL OUT. That’s the wrong answer.

The purpose of DIL is make up gas. It’s gas to get you to the bottom. You can’t breathe pure oxygen, so you need something to get you there. But, you’re on the bottom in 200’ of water and your DIL is gone. Do you need to bailout? NO! You have to abort the dive, but as you start ascending your loop volume is increasing and your PPO2 is plummeting. So you add oxygen.

I’ve co-taught with half dozen instructors who overlook this, and when I lay it out just like that they go, “oh yeah, that’s right”. I’d much rather be on the loop than on open circuit if it can be helped. Especially in a cave.

Oh, I’ll play too...

Being in a cave and out of dil, your solution to ascend and lower PPO2 may not be doable, specially if you’d have to go deeper before reaching the exit, but there’s an just as easy/simple solution to that

Hint... Another advantage of a BOV

 

[Superlyte27]

It seems that SCR, open loop, feathering O2, etc. have all been relegated to conversational aspects only for most MOD1 courses.

I think those things are in my standards. I’ll go and look now. I know that I’ve been teaching them. Thankfully, I can exceed standards if they’re not in there. But I’m pretty sure they are. I’m looking now.

 

[Superlyte27]

Oh, I’ll play too...

Being in a cave and out of dil, your solution to ascend and lower PPO2 may not be doable, specially if you’d have to go deeper before reaching the exit, but there’s an just as easy/simple solution to that

Hint... Another advantage of a BOV

Depends on the cave. If you’re in Indian and you’re out of DIL, you’re screwed. I hope you planned your bailout properly. If you’re in Ginnie, where the vast majority of the dive is at 100’. You’re probably golden. But, you are right, it’s situationally dependent.

 

[Pavao]

Depends on the cave. If you’re in Indian and you’re out of DIL, you’re screwed. I hope you planned your bailout properly. If you’re in Ginnie, where the vast majority of the dive is at 100’. You’re probably golden. But, you are right, it’s situationally dependent.

Dude, take a breath at your OC bailout gás and exhale it into the loop, lol. So simple isn’t it?
Be honest, did you just have that “oh, that’s right” moment?

 

[Superlyte27]

Nope, no mention of SCR mode in my standards until CCR Cave

 

[Superlyte27]

Dude, take a breath at your OC bailout gás and exhale it into the loop, lol. So simple isn’t it?
Be honest, did you just have that “oh, that’s right” moment?

LOL, that’s funny.
Don’t you think it would just be easier to plug in the whip from your bailout tank to your MAV?

 

[Superlyte27]

You guys set em up, I’ll keep knocking them down. LOL

 

[Superlyte27]

Admit it, you just had one of those, “oh that’s right moments”.