New Halcyon Rebreather?

[PEDiver]

The main reason for a BOV is, that in case of CO2 you don't need to switch regs.
Under this point of view the BOV of the Symbios might be useless.

I would argue that a BOV is great for sanity breaths and also for a quick switch to OC in case of an emergency to bailout to a safe gas. If you truly need to bailout, and stay on OC, you will want to eventually switch to your OC second stage, not stay on the BOV.

 

[SavageSeaCow]

I would argue that a BOV is great for sanity breaths and also for a quick switch to OC in case of an emergency to bailout to a safe gas. If you truly need to bailout, and stay on OC, you will want to eventually switch to your OC second stage, not stay on the BOV.

Unless you have a catastrophic failure of the flapper valve, bailing out should provide enough fresh gas for a co2 hit. Anything minor you should be able to bail then switch regs. That’s the one liability of the dual hose regulator BOV. If you predive your mushroom valves this shouldn’t be too much of an issue.

 

[rddvet]

I would argue that a BOV is great for sanity breaths and also for a quick switch to OC in case of an emergency to bailout to a safe gas. If you truly need to bailout, and stay on OC, you will want to eventually switch to your OC second stage, not stay on the BOV.

I would say if you’re bailing out to a small onboard cylinder, you need to go to a reg. If you’re plumbing off board dil which many of us are due to the risks of bailing to a 3L, then you stay on the bov. I won’t dive onboard dil for this very reason among others

 

[rddvet]

Unless you have a catastrophic failure of the flapper valve, bailing out should provide enough fresh gas for a co2 hit.

This is not fully accurate and why ,any of us don’t bail to onboard dil

@kensuf has a good story of why an onboard dil would not have been a good idea when his buddy had a co2 hit

 

[PEDiver]

I would say if you’re bailing out to a small onboard cylinder, you need to go to a reg. If you’re plumbing off board dil which many of us are due to the risks of bailing to a 3L, then you stay on the bov. I won’t dive onboard dil for this very reason among others

I currently have my Defender configured with onboard 3L so I have a necklaced second stage for bailout since my BOV is plumbed to the 3L. I've been thinking more and more lately about plumbing my BOV to my SM cylinder instead via a QC6 but have yet to make the switch. But I do agree bailing out to a 3L is far from ideal.

 

[grantctobin]

My BOV is plumbed to the 3L.

Is this a Thornton thing still? I thought it had gone the way of the dodo outside of them. Glad you're considering plumbing to offboard.

 

[PEDiver]

Is this a Thornton thing still? I thought it had gone the way of the dodo outside of them. Glad you're considering plumbing to offboard.

BOV plumbed to your onboard 3L is standard for the XCCR/Defender. I asked about this during my crossover and the answer mainly revolved around the idea that the 3L is fine for sanity breaths / quick switch to OC whereby you can then switch to your necklaced reg in the event you can't go back on the loop. My necklaced reg also breathes better than the BOV and the thought is, if you really need to bailout to OC, you would rather be on a reg you're comfortable with vs. having to use the BOV for a long duration of time.

I get the logic, but ultimately at the cost of one additional hose and a QC6, I can have the option of my necklaced reg or a BOV plumbed to my bailout cylinder and not having to worry about draining the 3L.

 

[rddvet]

Is this a Thornton thing still? I thought it had gone the way of the dodo outside of them. Glad you're considering plumbing to offboard.

Its definitely way more common still than I think it should be

 

[SavageSeaCow]

This is not fully accurate and why ,any of us don’t bail to onboard dil

@kensuf has a good story of why an onboard dil would not have been a good idea when his buddy had a co2 hit

We’re talking about a chest mounted unit so presumably it would be off board Dil. The question is about whether a BOV that essentially becomes a double hose open circuit regulator is a good idea for a CCR when you might be bailing due to CO2 hit potentially from a mushroom valve failure.

 

[davehicks]

We’re talking about a chest mounted unit so presumably it would be off board Dil. The question is about whether a BOV that essentially becomes a double hose open circuit regulator is a good idea for a CCR when you might be bailing due to CO2 hit potentially from a mushroom valve failure.

I'm not sure what a CO2 hit does to impact using the BOV. When you switch the BOV to OC, it closes off and seals the loop so any CO2 in there is out of the picture. The mushroom valves could have flown the coop entirely and the BOV in OC mode is going to work just fine.

That said, my Hollis BOV on my KISS has a piece of crap unbalanced 2nd stage. It's perfectly fine to quickly get off the loop. If I had to stay off the loop for an extended period, I would switch to my S600 strapped to the offboard dil/bailout.