Stage/deco/BO reg with inline shutoff

[flymolo]

Best to assume you won't hear it.
On a DPV with a thick hood and my bleh tinnitus, I can barely hear an actual free flowing 2nd. I'm more like to feel the bubbles in my armpit.



You have backmounted BO/dil but no 2nd stage or BOV on the left post? That's unusual.

I have a long hose off the right post and a qc6 off the left post, which plugs into the dil mav. The dil mav has two hoses which route to a bov and the head itself

 

[macado]

How often do you guys replace your opvs? i've got one on a ccr o2 reg and one on my left post backgas reg (for when i'm diving ccr since the second stage gets replaced with a qc6). Now i'm a feeling a bit anxious about leaving it on there all the time...

I just replace them when they start leaking or maybe when I rebuild a first stage. I try not to overthink it. I literally have a bag cheap DGX OPVs ($5USD) in my save-a-dive kit. I guess I'm pretty lucky. Mine don't leak that often and I've "saved" more people than I've had to use them myself. I consider these OPVs basically a disposable items. I never bothered with the rebuildable ones honestly.

I think a lot of people seem to forget (it goes without saying..) is why is the OPV leaking? In my experience It's probably 50/50 shot that it's a very slow IP creep on the first stage. People don't notice it because once they add diluent or O2 it drops the IP enough to not "leak."

I'm only halfway through my mod1 yet so still very new to the silence of CCR diving, but I feel like you would definitely hear if you accidentally purged a BO reg, no?

Depends. I seem to be hyper-sensitive to bubble noise even with a thick hood. I can literally hear bubbles escaping through my hood at Ginnie on deco if I'm the only one around on CCR and solo. I personally can absolutely hear a purged regulator on CCR.

With a mixed teams (CCR / OC) and scooter then it's harder to notice for me. Lots of factors. On scooters it is extremely easy for regs to free flow. If it's a stage I am not breathing I make sure to crack the valve on/off frequently to re-pressurize.

My standard rebreather configuration is two sidemounted bailouts with a with bungeed necklace regulator that is always on. My 2nd bottle is off but charged. I make sure to re-charge it frequently. It's sort of a habit, every so often I just re-crack the valve on/off and go about my dive.

 

[Degenerate]

Best to assume you won't hear it.
On a DPV with a thick hood and my bleh tinnitus, I can barely hear an actual free flowing 2nd. I'm more like to feel the bubbles in my armpit.[/QUOTE

How thick is your hood? Are you with a mixed team? DPV or no DPV? In a 10mm+ hood I don’t think it’s super likely to hear.

Good point about the DPV, didn't think about that really.
I use a 5/7mm hood, would definitely hear bubbles if not on a DPV, but doubtful if I was using one.

 

[flymolo]

Good point about the DPV, didn't think about that really.
I use a 5/7mm hood, would definitely hear bubbles if not on a DPV, but doubtful if I was using one.

all it takes is one nearby oc diver to ruin the blissful silence

 

[Degenerate]

all it takes is one nearby oc diver to ruin the blissful silence

I've been accused of that for a while now until I finally had enough and took the plunge to CCR, the silence is the best part so far

 

[tbone1004]

all it takes is one nearby oc diver to ruin the blissful silence

being on a wreck or reef with just CCR's and then a cattle boat shows up.... uggh

 

[rjack321]

I have a long hose off the right post and a qc6 off the left post, which plugs into the dil mav. The dil mav has two hoses which route to a bov and the head itself

What unit is this? I assume you're doing this to simultaneously offboard to a new dil and new BOV gas.

I guess I would put one of the highland ones on that left post 1st. But I don't like having all your eggs in that one BO/dil basket. A leak at the BOV or anywhere from the female QC6 downstream takes out both and you're forced to add dil from the long hose or bail depending on what's happening. I split my feeds, one for dil & wing and a 2nd to the BOV.

But you could instead take one hose direct off the 1st stage to the BOV. Just leave the hose on the 1st stage and unscrew it from the BOV when breaking things down.

Then the 2nd hose to the QC6 and dil MAV

No OPV needed anymore as you either have a loose LP hose with nothing on the end of it or you have the BOV 2nd stage to safely leak.

 

[flymolo]

What unit is this? I assume you're doing this to simultaneously offboard to a new dil and new BOV gas.

I guess I would put one of the highland ones on that left post 1st. But I don't like having all your eggs in that one BO/dil basket. A leak at the BOV or anywhere from the female QC6 downstream takes out both and you're forced to add dil from the long hose or bail depending on what's happening. I split my feeds, one for dil & wing and a 2nd to the BOV.

But you could instead take one hose direct off the 1st stage to the BOV. Just leave the hose on the 1st stage and unscrew it from the BOV when breaking things down.

Then the 2nd hose to the QC6 and dil MAV

No OPV needed anymore as you either have a loose LP hose with nothing on the end of it or you have the BOV 2nd stage to safely leak.

interesting ideas, thanks. I’m diving a fathom and usually run dil/bo off a set of manifolded lp50s

 

[Lanny]

Adding an in-line shut off to a stage cylinder is solving a problem that is easily fixable by other means, and introduces a number of more serious issues and failure points. I don't know of any reputable tech or cave instructor who would advocate this. I have seen dislodged stage regulators a few times, and you can easily fix by depressurising and tightening the DIN wheel. Even if you have a failure that cannot be rectified, then feathering the valve will allow you to access the gas without wasting too much. You will still be fine if you practice safe gas planning - subtracting stage gas from back gas/SM gas in cave, or 1.5 times deco gas in vertical diving. I do use shut offs for my CCR, but would go as far as to say they have no place in OC diving.

 

[rddvet]

interesting ideas, thanks. I’m diving a fathom and usually run dil/bo off a set of manifolded lp50s

you don’t have a necklaces reg on the left post? My wife dives her fathom with bm 50s set up in a “dir configuration”. Long hose right post and necklaces reg left post. She also runs a bov. I know Charlie and a couple other people don’t dive a necklaced reg on the left side mounted bailout but I’ve never seen that in the bm bailout setup. I personally don’t have a reg attached to my left sm bottle just the qc6. It feels wrong to not have a reg on the left sm bottle but I’ve gone round and round with several of the fathom instructors about it, and it seems although it’s nontraditional it’s acceptable. I have a second stage with a female qc6 in my pocket just in case. The lack of a reg in the bm setup is not as common among fathoms I believe.