Northwest Dive Club

I was talking to a friend yesterday about my discomfort about diving with CCR folks. We talked a fair bit about bailout and rescue procedures, but the one thing neither of us could really come up with was an answer to this question: How do I know that a CCR diver is doing all the pre-dive preparation and checking that he is supposed to do? With an OC diver, I know exactly what they should do, and if necessary, I can more or less force them to do it. But do CCR divers have written checklists I can ask to see, or how else can I know whether the person is going through his proper sequence? A number of rebreather accidents I have read about seem to be as a result of someone NOT properly setting up or checking his unit, so I think the question is a reasonable one.

from my experience as a mixed team diver there are things to look for and every dive i do i ask lots of questions, poke at things and ask "whats that for" , ask how much life is left on there scrubber, also you can know what the readings on a hud are. it is still up to them to fully set it up right though, i cant tell you the number of times josh has bagged a dive because he did not want to rush setting up his meg and go thru all the steps to do it safely, was i bummed? yes but i knew he was making the right call.

iam sure the ccr crew will fill in more but thats my perspective from the oc side. in the end if you feeel safe with someone it shouldnt matter if they are a recycler, they are either carefull and thorough or not.

really great question too by the way.

There are two main steps to CCR preparation for a dive, the pre-dive assembly of the unit and the buddy check/dive site checks. You won't be able to "verify" that someone has done all the items on the pre-dive checklist, because divers typically do this at home the night before, etc. There are about 25 steps to this, if memory serves. This is an extremely critical procedure for a CCR diver, and doing pos/neg checks for the breathing loop valves, head and breathing loop w/ counterlungs is critical, packing the scrubber properly is critical, properly calibrating the computer/HUD, replacing aging O2 sensors, getting o-rings seated properly if they become dislodged, sterilizing the loop every week... all of this is extremely important and CCR divers do not take any of this lightly. But, as a matter of reality there 's no way you'll be there watching them do this stuff, so you have to trust that if a diver has gotten to that particular level of diving they've done so responsibly and with the proper training (for instance, you're not allowed to actually take possession of your breathing loop/DSV until you're certified). But, there are analogous amounts of trust that go into diving with an OC diver. You have to assume that they have had their tanks properly inspected, gasses analyzed accurately, o-rings replaced when needed, regs serviced on time, computers set for the dive profile and gas types/supplies, etc. - each diver is responsible for him/herself at the end of the day, along with the duties of being a good buddy. Proper gear maintenance and dive preparation *is* a form of being a good dive buddy.

As for the second phase (day of), I wouldn't think of it as "catching" someone or "forcing" them to do something you identify as them not having done, I'd think of it as being able to do the in water buddy check, understanding what someone is doing when they're pre-breathing their unit (activating the scrubber) and just generally being a good, helpful dive buddy. The day-of check involves doing a pos/neg of the breathing loop with the counterlung exhaust valve shut, to check for leaks. Pre-breathing the unit to "warm it up" at .4 PPO2 or higher for a few minutes (usually on the walk from the car into the water and while putting on fins, etc.), then checking all the valves for good connection, SPGs for adequate gas supplies, lock and unlock the diluent add valve, O2 constant flow for confirmation of connection, bubble check and just generally noticing if anything looks out of place, and also to familiarize yourself with the CCR diver's gear configuration (connections and releases, where SSs are located, etc.). Of course, all of this is specific to my unit, the COPIS Megalodon - and every unit is slightly different.

CCR divers take into account when they are diving in a mixed team or paired up with a diver who is not as familiar with his/her unit. I remember the first time I dove with John using his KISS Classic, it took about 5-10 minutes for him to explain the basics to me about what he wanted me to do if something went wrong, what I might or might not notice about his diving being different than mine, etc. It's better to learn in steps than all at once, as burntchef and Ken now know. Each dive they probably learn a little more about CCRs and it's additive. Plus, we all talk about gear all the time just for fun, so I think there's a certain amount of "osmosis" that goes on.

I hope this was helpful and thanks for asking!

LCF wrote:I was talking to a friend yesterday about my discomfort about diving with CCR folks. We talked a fair bit about bailout and rescue procedures, but the one thing neither of us could really come up with was an answer to this question: How do I know that a CCR diver is doing all the pre-dive preparation and checking that he is supposed to do? With an OC diver, I know exactly what they should do, and if necessary, I can more or less force them to do it. But do CCR divers have written checklists I can ask to see, or how else can I know whether the person is going through his proper sequence? A number of rebreather accidents I have read about seem to be as a result of someone NOT properly setting up or checking his unit, so I think the question is a reasonable one.

Good question- and Calvin and Howard hit the major points already, but I'll chime in anyway.

If you want to do a good thorough buddy check on a CCR buddy, you have to invest the time to learn a little bit about that unit- they are not standardized, although there are many similarities. CCRs are actually very simple beasts, at the core- they just look intimidating. Once you learn how one works, and it doesn't take very long, you're gonna find that "learning" another one is pretty easy.

The predive check that Calvin and I were taught mostly involves checking to see if valves are turned on, manual add valves are working, and nothing is leaking- we can check each other over in less than a minute, without rushing.

When I'm diving without a CCR buddy, I check myself (Easier than it sounds) and ask my OC buddy to look for leaks when we go under.

Next time you see me at the cove, you're welcome to come get the nickle tour of my Meg, if you want.



edit- almost forgot- yes, the Meg has a written predive check sheet- I'll copy it and post it here later. I'm pretty sure all CCRs have them. That would be the best way to be a good buddy with a CCR diver, I suppose.

Great discussion, we should workshop through mixed team protocols sometime Lynne, maybe some other CCR divers with dissimilar units could come and you may see how simple it is to identify the key components to each unit and verify what the CCR diver may need in rescue situations. Possibly other curious diver such as yourself will join us too. Sounds like a date should be made?

mattwave wrote:Great discussion, we should workshop through mixed team protocols sometime Lynne, maybe some other CCR divers with dissimilar units could come and you may see how simple it is to identify the key components to each unit and verify what the CCR diver may need in rescue situations. Possibly other curious diver such as yourself will join us too. Sounds like a date should be made?

I would come be a part of that, if you set something up, Matt- let me know if you do.

Nailer99 wrote:I would come be a part of that, if you set something up, Matt- let me know if you do.

I would, too, as an OC guy...

I absolutely love diving with a mixed team. one it is fun to dive with your friends still that dive CCR and two if i have a problem there is no handing me a regulator, but the give me a fresh new bottle of gas. unused and ready for me to finished the dive. yes of course by finish i mean abort and do any nesessary stops. on the other side if they have a situation at hand i am like a freaking gas station for them, i have my doubles and my deco gases for them to share.

Josh, Calvin would you agree you like having a mobile gas station with you?

But i also agree with Burntchef ask questions whats that thingy do. I still learn every time i dive with someone on a CCR another reason why they love it so much.

I just don't care for how unsimple it is to just go diving.

Maverick wrote:I just don't care for how unsimple it is to just go diving.

It seemed pretty unsimple to me too!

scottsax wrote:

Nailer99 wrote:I would come be a part of that, if you set something up, Matt- let me know if you do.

I would, too, as an OC guy...

i haven't yet dived with anyone on a rebreather yet, but a class or seminar like this would be a great way for me to learn about CCRs as well as how to be a buddy to a CCR diver. keep us posted if this develops.

I would be very happy if somebody put a seminar thing like that together. A lot of my discomfort with the idea of diving in mixed teams is simply due to my own ignorance.

It's agreed then, next how about a date, we should should start at the shop in the classroom then migrate to the beach, labor day weekend is out, and so is the following weekend, how about the one after that?

The weekend of the 12th would work for me.

As long as it's not Friday, I'm in...

If the weekend's good for me, I'll volunteer to come out with both my Evo and an older Drager SCR, perhaps Nailer or Calvin can do the Meg, and we can scrounge up a KISS to do a very high level run through of unit-specific differences that might matter. There are some really interesting ones including where things are located, which way gas flows through the loop, whether leaving the gas valve on could cause problems, the interesting bits around offboard gasses, etc.

I don't know how much rebreather divers learn about units other than their own, but perhaps a seminar like this would be interesting to some of them just for cross-training, as my guess is that most rebreather teams are "mixed" around here, too.

LCF wrote:I don't know how much rebreather divers learn about units other than their own, but perhaps a seminar like this would be interesting to some of them just for cross-training, as my guess is that most rebreather teams are "mixed" around here, too.

I'm just starting to learn the ins and outs of a few other units; but once you learn one, it's fairly easy to figure out the basics of where the 02 and dilluent addition controls are. Those, the P02 display, and how to open or close the Dive Surface Valve, along with venting the counterlungs, are the really important stuff to know about your buddy's CCR- I know it sounds kinda complicated when I write it all out like that, but trust me- it's not.

my o2 cents:

-if at all possible I prefer pairing up CCR with CCR and OC with OC, no ego trips, it's just that there are quite a few differences just between CCR units to explain... it's a lot to explain if you are not familiar at all with rebreathers, I've found it's almost hopelessly so, and I often consider myself a solo diver in such cases (actually I like to keep that mindset to some extent all the time anyway). that said, I enjoy diving with folks who dive a wide range of rigs, OC, eCCR and mCCR and I feel that there is very little another diver will be able to do for me in any case, adequate prevention is the main cure for rebreathers, IMHO.

-for an OC/CCR mix team, I have my OC buddy do a basic buddy check, looking for anything loose, dangling and anything unclipped before we get in the water. I ask for a bubble check at 15 ft, having the diver swim around me, or I do a spin in front of them, with them aware that anything but a tiny fiz from a swivel pin or a pressure gauge should be addressed and that any bubbles at all coming from the loop hoses or counter lungs is bad and requires my attention. I explain that bubbles on descent are unusual and best to bring them to my attention, after that bubbles being released upon ascent, much like from a dry suit or a wing is normal. I do a really basic explanation that on the surface, po2 is nearly identicle to %02, such as .5 indicates 50% o2. I explain that anything ever below .21 at any depth is deadly bad. Even if they are tec divers I explain that I fly between .7 and 1.3 (without getting too much into what partial pressure really means), that since I dive a manual injection rig, that it's not as exacting and not to be as alarming if there is some variation between .9 and 1.3, even as high as 1.5 at depth for short periods, while more than momentary deviations from a constant set point for eCCR's (typically .7 upon initial descent and 1.3 at depth) on the other hand can be a sign of a problem with the set point controller or o2 supply.

I also let them know that if I am conscious but out of it, that it's probably safest to add dilluent, which will lower my po2 if too high while increasing it above what is needed for consiousness if too low, that it's usually good either way, assuming normaxic mixes. If i'm unconscious I asked to be corked to the surface via inflation of wing and that they come up at a safe ascent rate, focusing on their safety primarily.

That is about as complicated as I get, I figure anything else is too much to absorb at once. On following dives with the same person, I will add layers accordingly, going into how to read my HUD and so on.

hope that's valuable, great thread!
g

I dove with LoanWolf this weekend. He's got a Revo.

The big difference between buddying up with a CCR vs. OC is this..............................

Pez7378 wrote:The big difference between buddying up with a CCR vs. OC is this..............................

"..................................." ? He left a trail of breadcrumbs?

Pez7378 wrote:I dove with LoanWolf this weekend. He's got a Revo.

The big difference between buddying up with a CCR vs. OC is this..............................

Uh......you mean "there is no difference?" Or did Joe stick an icepick in your neck as you were about to type a long explanation, causing your finger to stay on the "." key for a few seconds before you quietly slid to the floor, twitching?

Josh you have such an active imagination. How long before the twitching stops?

There was no difference. I dove. He dove. We both dove together!

Pez7378 wrote:Josh you have such an active imagination. How long before the twitching stops?

There was no difference. I dove. He dove. We both dove together!

Joe will need to jam a second icepick into your neck in order to counteract the twitching from the first one.

Probably.



Makes sense, anyway.


Only one way to be sure, right?

I think it would be a great thing to do so count me and my rEvo in. This weekend as it is a holiday weekend is probably not a good one.
There really is not too much of a difference in a CCR or OC buddy check. And only one real difference in the water and that is rescue technique.

1. Buddy check. There are only a few differences.
a. No S-Drill – as we do not have a long hose to pass off. But OC should pass to us in the buddy check.
b. CCR O2 and Dill bottles - do not touch the valves as we have them only open a turn or so not full and back a little like OC.
c.Bailout bottles – The bottom mix which should be slung on the left side will be on and deco bottles will be charged and off as with OC.
2. Rescue Technique – This you should go over with your dive buddy no matter if they are CCR or OC diver as the units are different so the technique is different.
a.With OC you grab the 2nd stage and push the head back into the manifold and then inflate the BC.
b. With CCR it is best to reach over the shoulder form behind and hold the DSV (mouthpiece) in and press the diluent button. This does two things, fills the loop with new good gas and inflates the counter lungs to give positive buoyancy as a BC would. Each unit is different as to where the dil button is located.
i. On my rEvo it is located on the bottom left side of the case and marked with “press button to rescue” and an arrow pointing at the button.
ii. The Meg it is located on left side counter lung on the front. And has a lock-off that must be opened before it will operate.
iii. The KISS it is a button on the back side of the head of the unit.

One thing I like all my OC buddies to have is LP inflator hoses on their deco bottles. That way if I have a O2 failure all I have to do is come over and get a shot off their 100% or 50% bottles every 3 to 5 minutes or so and can stay on my unit. Or if I have a dil failure I can take a shot of their back gas to replenish the loop if I have to. Over all there should be no concerns with a mixed group as there is very little difference in diving. Other than OC is noisy as hell in the water.

Greg

to dredge up another thread, Leon (from innerspace AKA megalodon) and I are going to start working on this workshop. We should be in need of some crash test dummies in the next several weeks. We also hope to video it and make that available for the "open circuit buddy for the rebreather diver". The hope is to allow more mixed 'team' diving and less solo diving due to loss of buddies when making the switch from OC.

You guys in?