Rebreathers (CCR) What Recreational divers need to know

[scubadada]

This is a very good thread, thanks @bowlofpetunias

There is a slowly increasing number of rebreathers on the boats I dive on out of Boynton Beach, West Palm, and Jupiter, Florida. Sometimes the rebreather divers are doing one long technical dive on one of the wrecks, while the rest of us are doing 2 recreational dives. Sometimes, they are doing the same recreational drifts we are doing. Occasionally, one of the rebreather divers has ended up being my buddy. In that case, I have the discussion that @stuartv has described, above. Mainly, I just want to know how I can assist in an emergent situation and have a passing familiarity with their particular equipment.

Back in 2007, my son and I did a "rebreather experience" with Divetech on Grand Cayman while they were still at Cobalt Coast. It was a half day, very well spent. We learned a bit about rebreathers, assisted in assembly, went on an hour dive at Turtle Reef (about 20 minutes were spent neutrally buoyant ), and assisted in breakdown. Though I may never dive a rebreather again, much of what I learned will always be valuable to me.

Diving on a mixed boat with a rebreather? Need or want a buddy? I'd be glad to dive with you

 

[boulderjohn]

There is a slowly increasing number of rebreathers on the boats I dive on out of Boynton Beach, West Palm, and Jupiter, Florida.

That has been my observation while diving in the Pompano Beach area as well. I sense that the percentage of scuba diving occupied by rebreather divers is expanding rapidly, and it is becoming more and more important for all of us to understand them.

 

[JohnnyC]

Of course if you are diving with a CCR buddy a buddy check and directions are necessary.

Simple to me is...

If I see a CCR diver with a slung cylinder.. I know he has a chance of sharing air.. If he doesn't i will assume not
If I see red lights flashing.. I will try to point it out to him.
If he doesn't respond I will look for a bail out lever or button like in the picture
I need to keep the mouthpiece in place so his loop doesn't fill
If I can get him to the surface while doing that great if not I get help
I can only do what I can do and I hope non of this is ever needed.

Here's the problem, the things you've mentioned are based on assumptions, and each of them has issues.

1) Maybe, maybe not. What if it's deep bailout and sharing will put you to sleep? What if he doesn't have anything slung but he's diving an SCR with a long hose. You may not see any slung tanks, but it doesn't mean he can't share air.
2) What if the red light you see is on their HUD? Red light doesn't mean bad. What if you can't get his attention because he's focused on some other task? (which leads into 3)
3) Just because he doesn't respond doesn't mean you should throw the lever. Unless you know for sure beforehand, you could cause some issues.
4) What if he's bailed out and you're only seeing him in the middle of switching to a second stage? Sure, he shouldn't have the loop out of his mouth until he's got another viable air source already in hand and ready to go, but people to goofy stuff all the time.
5) That's not a bad idea, but grabbing a CC diver and swimming up without double checking all the other things first could be quite disastrous if you're not fully capable of controlling the situation during ascent.
6) The best way to deal with this is to talk with the diver beforehand and get a solid idea of his/her wants/needs and how to go about accomplishing those. Trying to make a checklist for diving with a CC buddy is doomed to fail because each situation is very individual, and dependent on several other things.

I don't want you to think I'm being purposely argumentative, I just wanted to point out some flaws in your train of thought. Because each situation "depends" as stuartv says, you can't just go with a set of rules and assume it's the right choice. The right choice will be very situationally dependent and really the only "rule" you should have is "talk to your buddy beforehand and make sure you both understand the plan."


ETA: I think scubadada's rebreather experience is HUGELY advantageous for an OC diver to partake in simply because many of the things covered in an experience like that will directly impact your ability to dive with a CCR diver. Even understanding the basic concepts of rebreather function and physiology will go a long way to expanding your mental toolbox in the event you're in a situation where you're diving a mixed team.

 

[KevinNM]

Not a common case for sure but it does happen. I imagine the same thing happens with a group of cave divers swimming around the cavern area during deco with OW people around.

I saw a couple in Catfish sink (entrance to mantatee). They pretty much just hanging there with their DPVs and bailouts looking like they were sleeping. And then I looked back and they were not there any more.

 

[MadUKDiver]

A long time ago Stephen Hawkins (aka Dive Mole) put together a buddy info page for people diving with CCR (AP Inspiration specifically). Seems his website is long gone but Wayback Machine has an archive here

He also produced a 'card' that could be laminated which (hopefully he won't mind) I've attached to this post.

 

[RainPilot]

A long time ago Stephen Hawkins (aka Dive Mole) put together a buddy info page for people diving with CCR (AP Inspiration specifically). Seems his website is long gone but Wayback Machine has an archive here

He also produced a 'card' that could be laminated which (hopefully he won't mind) I've attached to this post.

I really like that card. I think I need to do something similar for my unit.

 

[northernone]

One thing I forgot to mention. If you need air do NOT take the reg from my mouth to get it. With a rebreather the trendy "what's in my mouth is breathable, I'll donate my primary" thinking does not work.

If I'm not diving with you and not prepared to share air I'm possibly useless as a shark as an air source.

It entirely depends on the individual rebreather diver and his equipment configuration. The predive discussion differs greatly.

To illustrate, I've dove 4 different rebreathers along side OC divers in a recreational context, one buddy has experienced diving with me on 3 different units.

1. Alternative air source attached to a bail out tank AND a second o2 cylinder and a reg not to be donated and blinky lights to watch. Slow but significant buoyancy loss if flooded.
2. No alternative air source, no blinky lights. Minimal change in buoyancy if flooded.
3. Air2 alternative air source, different blinky lights. Slow but significant buoyancy loss if flooded
4. BAIL OUT valve for me, alternative air source for my buddy. (Second dive, no alternative air source, loaned the pony tank to another diver) Slow but significant buoyancy loss if flooded.

Each of those configurations require a different briefing.

To keep my answer basic, ask your buddy for the information specific to his rebreather.

Regards,
Cameron

 

[northernone]

A long time ago Stephen Hawkins (aka Dive Mole) put together a buddy info page for people diving with CCR (AP Inspiration specifically). Seems his website is long gone but Wayback Machine has an archive here

He also produced a 'card' that could be laminated which (hopefully he won't mind) I've attached to this post.

Thank you!

An excellent resource to help a competent buddy.

 

[sunnyboy]

I totally agree with JohnnyC. In addition, it should be pointed out that rebreather divers are a lot like the proverbial herd of cats. If you line up 10 rebreather divers, you are very likely to get 10 totally different rigs, where the differences are NOT insignifcant. You are also as likely to get 10 totally different sets of protocols, checklists, and procedures.

In other words, ASSUME NOTHING when it comes to rebreather divers, with the possible exception that, same as every other diver, the thing that goes into the mouth should contain breathable gas for the diver.

 

[sunnyboy]

I should add that if you are diving with a rebreather diver, then you SHOULD ASK for a briefing on the gear and what the diver would want you do do in the event of something happening underwater.

One caveat: choose the time to ask carefully. If the diver is "doing something" to or with the unit, then let them finish. Getting interrupted on OC is bad, but on a rebreather it can be catestrophic.

Also, if you ask nicely when they aren't busy, and they just blow you off and won't talk, then maybe find someone else to dive with and ignore them. Bad manners exist in OC as well as rebreathers. Most rebreather divers I know will tell you if they don't want to talk, but will usually say "ask in X minutes" or similar.