Rebreathers (CCR) What Recreational divers need to know

[lowviz]

Except at 100' with a hypoxic loop, a BOV switch can be the difference between bringing up a brain-dead corpse or a viable resuscitation. ...//...

Yes, but this is a numbers game for the partially informed. Play the odds.

Would you consider the reason for an RB diver being unresponsive as most likely due to hypoxia? If so, would you be willing to guesstimate that likelihood as being at a greater than 50% probability?

 

[Gareth J]

Again, I'm not getting some of this discussion. If you've taken a rescue course, you have already discussed and even done some rescues on unresponsive divers found on the bottom. The steps are the same no matter what configuration the unresponsive diver is wearing.

1. Do not put yourself in danger. Two victims is worse than one.
2. Do get the diver to the surface. If they are unresponsive, they need to be on the surface for proper medical attention.
3. If the breathing device (regulator, mouthpiece) is in the unresponsive diver's mouth, try to keep it in place while you safely (as safely as possible) get them to the surface.

There's lots of other stuff and details, but this is the essence of rescuing an unresponsive diver of any flavor. Whether OC recreational, OC technical (twins, stages, etc) or Rebreather, you do the same stuff - get them up if you can do it safely.

Farting about underwater trying to figure out which lever is what or whether the bottle is stage or bailout or what button to press is just wasting valuable time. Get them on the surface if you can do it safely.

I don't disagree with any of your points.
The one big issue with any rebreather is the breathing loop. It adds two complications.
Positive buoyancy - you have three buoyancy cells to deal with, Jacket/wing, drysuit, and breathing loop.
In many ways this is the lesser concern because it should mean the diver reaches the surface.
Negative buoyancy - flooding the loop, will run a very high risk that the diver becoming so negative that you are unable to either get them to the surface or keep them on the surface.
Switching a BOV to OC stops the risk of the loop flooding. Where you don't have a BOV, flushing the loop ensures has the added benefit that there is expanding gas in the loop reducing the risk of flooding.

 

[TONY CHANEY]

Again, I'm not getting some of this discussion. If you've taken a rescue course, you have already discussed and even done some rescues on unresponsive divers found on the bottom. The steps are the same no matter what configuration the unresponsive diver is wearing.

1. Do not put yourself in danger. Two victims is worse than one.
2. Do get the diver to the surface. If they are unresponsive, they need to be on the surface for proper medical attention.
3. If the breathing device (regulator, mouthpiece) is in the unresponsive diver's mouth, try to keep it in place while you safely (as safely as possible) get them to the surface.

There's lots of other stuff and details, but this is the essence of rescuing an unresponsive diver of any flavor. Whether OC recreational, OC technical (twins, stages, etc) or Rebreather, you do the same stuff - get them up if you can do it safely.

Farting about underwater trying to figure out which lever is what or whether the bottle is stage or bailout or what button to press is just wasting valuable time. Get them on the surface if you can do it safely.

Some of the best advice given on this thread! Rescue protocol is the same just like a code Blue situation...BLS vs ACLS/PALS. (Basic Life Support vs. Advanced Cardiac Life Support). When in doubt, do the basic. I have dived with mixed teams a lot, SM, BM, RB, etc. and as a new rebreather diver and past mixed team diver, I can add that the RB diver has less situational awareness due to having to monitor hand sets and computers. Please go to the extra length to get our attention.
Great thread!

 

[stuartv]

This whole discussion reminds of a funny (only after the fact) story that happened to my CCR buddy a few weeks ago.

He was diving some deep wrecks off the coast of Ireland. The wrecks ranged from around 55m to 90m, depending on which wrecks they were diving each day. He was part of a group excursion of tech divers. I think they were all on CCR. My buddy and his buddy got in for one of their dives and were descending. They stopped not too far down, for my buddy to equalize. He was having trouble because of a bit of a cold, so they were paused in their descent. As they hung there, another diver came down and passed them on the anchor line. Literally, as they watched him go by, they saw him pass out and start to "fall" to the bottom.

They successfully caught him and got him to the surface. It turned out he had forgotten to turn on his O2 cylinder on his CCR. And, of course, had hypoxic dil.

The funny part was that he came back to consciousness on the deck of the boat, after they got him out of the water. As soon as he became conscious, he immediately put his DSV back in his mouth and breathed off it - and immediately passed right back out.

Apparently, in the end, he turned out fine. But, man! How lucky was he for two other divers to actually see him pass out and catch him before he sank and was lost!

 

[lowviz]

This whole discussion reminds of a funny (only after the fact) story that happened to my CCR buddy a few weeks ago..

...//... The funny part was that he came back to consciousness on the deck of the boat, after they got him out of the water. As soon as he became conscious, he immediately put his DSV back in his mouth and breathed off it - and immediately passed right back out. ...

I love this thread.

This is for you, stuartv, thanks for the laugh! It reminds me of something I've enjoyed reading more than once: Why Smart People Defend Bad Ideas

Not my words below they are from the link above. I'm not that smart. But I so love the following:

“Put simply, the fact that you’re not dead yet doesn’t mean that the things you’ve done up until now shouldn’t have, by all that is fair in the universe, already killed you. You might just need a few more data points for the law of averages to catch up, and put a permanent end to your short term thinking.”

 

[bowlofpetunias]

@stuartv For clarification my only goal in starting this thread was to get CCR and Basic OC divers interacting so they can hopefully dive safely together whether as buddies or just sharing a site.

I would only Demand information if I a CCR diver and I had a responsibility for each other during the dive and the CCR diver did not voluntarily initiate the necessary pre dive conversation. If they weren't willing to give me the information needed to dive safely with them I would not dive with them. My choice.. their choice.. simple.

A discussion about the dynamics of "Group diving" locally would be off topic for this thread.

 

[JohnnyC]

Seeing as this is the beginning scuba section, and I recognize that people have different definitions of "beginner," I'm not sure that a beginning scuba diver would have the skill, mindset, or wherewithal to affect a rescue of a CCR diver, and maybe the best advice would be to ask for another buddy instead of trying to put them in a situation they're not equipped to deal with.

Even someone who has certified as a rescue diver will be dealing with variables that they've never trained for, and potentially never seen before. The hard truth is that we as CCR divers accept that there is an increased risk when we go bubbleless. Expecting someone without any understanding of what we are doing to be a reasonable buddy and make intelligent choices probably isn't fair to them in the first place.

This thread is definitely making me reevaluate my own choices when diving in a mixed team. I think I'm going to change my own policy to only dive CCR with other divers who have piloted a CCR before. There are just too many variables to deal with when you're talking about non-CCR divers.

 

[bowlofpetunias]

Seeing as this is the beginning scuba section, and I recognize that people have different definitions of "beginner," I'm not sure that a beginning scuba diver would have the skill, mindset, or wherewithal to affect a rescue of a CCR diver, and maybe the best advice would be to ask for another buddy instead of trying to put them in a situation they're not equipped to deal with.

Even someone who has certified as a rescue diver will be dealing with variables that they've never trained for, and potentially never seen before. The hard truth is that we as CCR divers accept that there is an increased risk when we go bubbleless. Expecting someone without any understanding of what we are doing to be a reasonable buddy and make intelligent choices probably isn't fair to them in the first place.

This thread is definitely making me reevaluate my own choices when diving in a mixed team. I think I'm going to change my own policy to only dive CCR with other divers who have piloted a CCR before. There are just too many variables to deal with when you're talking about non-CCR divers.

Awesome point IMHO. If reading this thread makes an Open Water diver or a Rebreather diver rethink their position and decide not to dive with a mixed team we have potentially saved a life. If it leads to better communication or understanding pre dive the outcome could potentially be the same.

 

[bowlofpetunias]

I love this thread.

This is for you, stuartv, thanks for the laugh! It reminds me of something I've enjoyed reading more than once: Why Smart People Defend Bad Ideas

Not my words below they are from the link above. I'm not that smart. But I so love the following:

“Put simply, the fact that you’re not dead yet doesn’t mean that the things you’ve done up until now shouldn’t have, by all that is fair in the universe, already killed you. You might just need a few more data points for the law of averages to catch up, and put a permanent end to your short term thinking.”

Brilliant thanks for the link I will have to read that myself

 

[northernone]

Situation reversed yesterday for me.

Met up with an internet buddy for a dive. I was in recreational gear and he showed up with a rebreather.

His briefing was in water:
"here is how to deploy the bailout regulator if you need air."
- demonstrates his pony bottle hose routing. -
"If I'm unconscious and my mouthpiece is in my mouth turn this switch so I'll be breathing OC."
-demonstrates his bail out valve -
"If I'm unconscious and the mouthpiece is out of my mouth I'll be heavier to bring to the surface"
-shows me his BCD inflator-

Off we go.
Cameron