Bail Out Breather options?

[stuartv]

This is not for me. I am a long way from needing a BOB.

A buddy of mine just got home from a couple of weeks of very deep wreck diving. He dives an X. For his deepest dives, he was carrying 2 x 3L steels, 2 additional 3L steels - one backup of O2 and a second 3L just for gas for his wing and drysuit. Then he also had 4 x AL80 of actual BO gas.

I told him it sounds like he should really think about ditching all that and starting to use a BOB. His response boiled down to "I'm not sure how the plumbing would look" and "I have never seen any wreck divers using them."

I suggested he have a look at the KISS Sidekick mCCR. It seems like an obvious choice for use as a BOB. Is it?

What other CCRs would be good to look at as a BOB to go with an X as a primary (for deep wreck diving)?

 

[Jeremy Williams]

I dunno... that’s far beyond my needs too.

The Sidekick seems very reasonable... But I’d have to look at the FlexCCR just because of the many commonalities with the XCCR.

 

[JohnnyC]

CCR or SCR? Both ideas have merit, and it's a choice that needs to be made.

The simplicity of a PSCR like an RB-80 type running off nothing but bailout has lots of appeal in terms of requiring limited babysitting. Plug in your bottom gas, let the injectors take care of making sure there's enough volume at depth, and drive on. If you've gotta bail, it's fresh gas of a known PO2.

An mCCR isn't a great choice because you have to actively fly the unit even when you're not on it. No matter what you've gotta shut down your O2. When you bailout in anger, are you gonna remember to turn your gas back on when you're trying to suck a vacuum on the unit? Your only choice is a cut-off on the leaky valve, again, something you've gotta remember to play with during a sporty situation. And if you forget to turn off the O2, not only are you gonna waste gas as it pisses out the OPV, but you're also gonna be left with an unsafe PO2, which you'll need to rectify before breathing on it. People espouse mCCR's specifically because they require a more active diver. A BOB wants the least amount of attention required.

An eCCR should be similar to a PSCR in terms of attention required, essentially not much, as realistically the ADV is gonna control volume on the way down, and since you're not metabolizing any of the O2, it should pretty much just sit there until needed. Provided you're smart with your dil choice, you shouldn't have to worry about PO2 being safe. However, it's another thing that is gonna require monitoring.

On top of that choice, you've gotta decide if it's going to be a fully redundant system or if you're going to share resources between the units. Are you going to run one dil bottle for both units? Gonna share O2 if you're running a CCR? A Sidekick with a sphere and a Gambrill sleeve is a nice little standalone package, but you've gotta babysit it. An eCCR with onboard O2 isn't too difficult, there are several on the market and realistically O2 volume needs to be minimal. A Flex with a little 1L O2 squeezed in between the counterlungs could work well. An SF2 with a small tank strapped to it would also be a viable package. A PSCR just requires you plug in gas with a safe bottom PO2 before descent, and it's bailout that can be shared with the primary unit.

Carrying a CCR for bailout means you're still gonna need to carry some form of OC gas since you have no appreciable volume to fall back on. The fact is that no matter what your choice is, you're still going to have to carry an appreciable amount of OC gas in case of hypercapnia. Running a BOB doesn't mean you don't have to carry gas, it just means that you can carry less of it. The problem is, you're replacing a dirt simple solution with something complicated, so the juice really needs to be worth the squeeze.

Don Six dives a BOB. And he's opinionated. Would be a good person to pick his brain.

 

[Aquanomad]

Sidekick, side winder, flex, dive soft sm, sf2, anf maybe some of the chest mounts like the triton. Those seem to be the commercially available units. Iv been eye balling a side winder a while now to add to my revo. I think the mounting and routing would be clean. I like the dive soft bc its an all in one unit. Bottles on board. Plus I can remove at 20' and grab an o2. Just dont like being locked into their electronics and all of the bells and whistles. I had 2 flexs'. Just too long for me and adding the bottles made it pretty massive. The side kick has had a lot of field time but still requires mounting bottles and any of the side mounts are going to require some good spot on rigging and wob may not be ideal if out of position.

 

[JohnnyC]

Sidewinder won't work with a backmounted unit. If you want to use a Sidewinder, the other rebreather needs to be a sidemount unit as well. If I could get a Flex for cheap, it would be fun to play with one and see if there's a good way to get it to work.

 

[Aquanomad]

Seen a few guys using it with an Inspo with good success.

 

[happy-diver]

An old thing from one of the Thai cave rescue diver dudes

 

[Vicko]

There is a eCCR version of flex going around, might be a good choice.
I know of 2 divers using 2 sidemount liberties with no oc bailout except a stage of 02, their logic being that at depth OC bailout will not solve their hypercapnia problem anyway.

 

[tbone1004]

@JohnnyC Matt Vinzant is using one underneath his Meg, but it does require some changes in the backplate to stand it off. Probably not ideal on a boat where it messes with your CoG

@Vicko I wouldn't use a flex, even as an eCCR since it is not self-contained and is too long to mount something like a sphere on the bottom.

@stuartv have him look up Anthony Tedeschi who is wreck diving actively with bailout rebreathers. Edd Sorenson is using them now as well. The Liberty is IMO the best option for a BoB because it is eCCR, fully self contained, actually has a BoB mode on it's handset for dealing with the solenoid and what not. The other one is he should be looking at a rack for X-CCR for boat diving, the "standard" method for mounting backmount rebreathers is really inefficient IMO.

 

[kensuf]

A BOB won't get him out of needing appropriate amount of inflation gas and/or oxygen. If he really needs 4x 3L steels to provide enough lift and oxygen, he's still going to need that.

OTOH, he may be able to reduce what he is carrying by prioritizing and organizing some of his gases differently. Example, a bailout O2 deco bottle with an inflator hose on it may help him get rid of one of those 3L steel bottles (the redundant O2). An intermediate deco gas with an inflator on it may allow him to get rid of the 3L he's carrying to provide redundant lift.

Heck, even switching the spare oxygen bottle to a 6ft3 bottle (which should be good for about 3 hours) may lighten his load.