Question CCR Suggestion for Remote Boating Trips - Sanity Check

[lermontov]

Again, thanks to all the detailed threads here, I stumbled across a potential issue with the Revo, and perhaps BMCL's in general that's a big deal to me--caustic cocktail when going in to a head-down position. As mentioned, my primary reason for diving is macro photography, and for me that often means going nearly inverted to take the shot I want. Granted, there shouldn't be water in the loop to begin with, but finding out all at once sounds like a game over...

I appreciate learning from others

Cheers!

who told you that ? sounds like scare mongering -you need significant water in the loop in the first place to get a cocktail and if you had that much water then youd likely have to bail out anyway. I go head down all the time with no issues. trust me it doesnt just sneak up on you like your implying you can tell immediastely if you have water in the loop and theres a few ways to deal with it. If you have enough waster to make a cocktail youl feel resistasnce in the breathing first as well as gurgling sounds

 

[MrBlenny]

who told you that ? sounds like scare mongering -you need significant water in the loop in the first place to get a cocktail and if you had that much water then youd likely have to bail out anyway. I go head down all the time with no issues. trust me it doesnt just sneak up on you like your implying you can tell immediastely if you have water in the loop and theres a few ways to deal with it. If you have enough waster to make a cocktail youl feel resistasnce in the breathing first as well as gurgling sounds

I've been digging through some older threads here and came across it as a concern. Also agree that if I go the CCR route, I'll be bailing the moment I suspect the loop might be compromised, but if I can choose a unit helps mitigate the issue, that's of interest to be sure. Since there's no holy grail (yet) for units, I'm trying my best to learn the pro's and con's of various design types. I really like some aspects of the Revo, and other aspects, less so. And all of this is predicated on my very limited knowledge of rebreather design. Once I know a bit more, I'm hoping to find an instructor that teaches at least a few of the units that seem like good fits.

 

[lermontov]

I've been digging through some older threads here and came across it as a concern. Also agree that if I go the CCR route, I'll be bailing the moment I suspect the loop might be compromised, but if I can choose a unit helps mitigate the issue, that's of interest to be sure. Since there's no holy grail (yet) for units, I'm trying my best to learn the pro's and con's of various design types. I really like some aspects of the Revo, and other aspects, less so. And all of this is predicated on my very limited knowledge of rebreather design. Once I know a bit more, I'm hoping to find and instructor that teaches at least a few of the units that seem like good fits.

great -sounds like your approching it all the right way, always a good sign

 

[Wibble]

I've been digging through some older threads here and came across it as a concern. Also agree that if I go the CCR route, I'll be bailing the moment I suspect the loop might be compromised, but if I can choose a unit helps mitigate the issue, that's of interest to be sure. Since there's no holy grail (yet) for units, I'm trying my best to learn the pro's and con's of various design types. I really like some aspects of the Revo, and other aspects, less so. And all of this is predicated on my very limited knowledge of rebreather design. Once I know a bit more, I'm hoping to find an instructor that teaches at least a few of the units that seem like good fits.

Revo…. Uniquely the Revo has both scrubbers above the cells and lungs. This means that aside from a full flood — hint, you’d be bailed out by then — so a head up, down, left, right position simply cannot result in a caustic cocktail as water cannot flow through the scrubberS.

All other single stack rebreathers (that is virtually all of them) have the cells on the top end of the scrubber stack so will have water flow through the scrubber when head down.

 

[mr_v]

Revo…. Uniquely the Revo has both scrubbers above the cells and lungs. This means that aside from a full flood — hint, you’d be bailed out by then — so a head up, down, left, right position simply cannot result in a caustic cocktail as water cannot flow through the scrubberS.

All other single stack rebreathers (that is virtually all of them) have the cells on the top end of the scrubber stack so will have water flow through the scrubber when head down.

You can get caustic cocktail without a full flood provided that you make a few moves that can let the water in through the scrubber. Not a big deal, just bail out. I did.

For robustness and ease of assembly, you can't beat rEvo. Follow these rules:

- Head up or down makes terrible WOB
- If you suspect a flood, bailout
- Bring $ to replace the lungs (every decade or so)

Otherwise, you're good.

 

[MrBlenny]

Revo…. Uniquely the Revo has both scrubbers above the cells and lungs. This means that aside from a full flood — hint, you’d be bailed out by then — so a head up, down, left, right position simply cannot result in a caustic cocktail as water cannot flow through the scrubberS.

Great info. So, short of swimming on my back (no real reason to), the sorb will stay dry?

All other single stack rebreathers (that is virtually all of them) have the cells on the top end of the scrubber stack so will have water flow through the scrubber when head down.

So the lack of a CL water trap in the Revo is mitigated by the design topology. Do you find the (comparatively) oversized cover to be difficult to properly seat? I know from some pond plumbing projects that larger threaded caps and fittings can be a pita to deal with, but that may not really correlate here.

 

[MrBlenny]

You can get caustic cocktail without a full flood provided that you make a few moves that can let the water in through the scrubber. Not a big deal, just bail out. I did.

For robustness and ease of assembly, you can't beat rEvo. Follow these rules:

- Head up or down makes terrible WOB

This is surprising to me; I would think the position of the lungs would be at their best in those orientations since they and the divers lungs would be in the same water column depth. It seems my intuition was wrong.

- If you suspect a flood, bailout

Agreed. Since it's my boat I can always get back in the water once the issue is properly resolved on deck.

- Bring $ to replace the lungs (every decade or so)

Otherwise, you're good.

I could *probably* justify getting a new unit once a decade, so new lungs sounds reasonable enough

 

[broncobowsher]

The large cover on the rEvo isn't an issue to get to fit. It is double O-ring, not threaded. If anything the battery box needs a little nudge for the cover to seat. Takes half a second to do and is second nature to building one.

 

[MrBlenny]

The large cover on the rEvo isn't an issue to get to fit. It is double O-ring, not threaded. If anything the battery box needs a little nudge for the cover to seat. Takes half a second to do and is second nature to building one.

I wasn't thinking it was threaded per say, but was wondering if it was fussy about tightening. I've come across warping issues with face seals in some instances (non-diving) where there was a narrow zone between loose/leaking and over-tightened (warped) leaking. Sounds like this is not at issue with the Revo.

 

[rddvet]

Sounds like this is not at issue with the Revo.

It's got a bunch of issues, but that's not one of them.
Do yourself a favor and look at how many proprietary parts there are on a Revo, and look through threads about the stupid things like expensive required routine maintenance (supposedly it's cheaper now) and the need to send in for counterlung repairs.