The big question about ccr… which one

[GiraffeMarineSalvage]

I don't get the hype and hope for Solid State O2 sensors.

One word: trust.
Rebreather manufacturers have done an awesome job working within constraints of galvanic oxygen sensors (and developing rules to reduce likelihood of multiple failures at an inopportune time) but when in comes to anything giving life critical readings it sure would be better if failed sensors gave null readings instead of lying..

 

[SavageSeaCow]

One word: trust.
Rebreather manufacturers have done an awesome job working within constraints of galvanic oxygen sensors (and developing rules to reduce likelihood of multiple failures at an inopportune time) but when in comes to anything giving life critical readings it sure would be better if failed sensors gave null readings instead of lying..

Add to that the issues of faulty calibration etc. and ss does seem to have a lot to offer. Not necessarily perfect but a big step in the right direction.

 

[Superlyte27]

Glad you used sound judgement and learned from others.
My CCR instructor actually made a point to bring up a fatality related to a CCR diver attempting to force themselves through a restriction they were unable to fit through and we went through what should have been done with the benefits of hindsight. I believe it was a different incident than the one you alluded to (and I am not personally familiar with Ginnie Springs), but seems like pure speculation diving an mCCR was a contributing factor to the incident you vaguely referenced as opposed to central contributing factor likely being diving beyond the safe capacity of the combination of team/diver/equipment at a given moment in time.

You would be wrong in your assumption.

 

[Superlyte27]

If someone is catatonic aren't you bailing them out because of potential break through, flooding or caustic? Assuming a BOV of course.

I'm in the group of people waiting on SS sensors (and building a solid base of OC deco diving knowledge) before making any move into CCR so my questions are simply academic.

No BOV and you’re not moving a catatonic diver from CCR to bailout. But, even if you were, it’s still a lot to deal with.

 

[Superlyte27]

Add to that the issues of faulty calibration etc. and ss does seem to have a lot to offer. Not necessarily perfect but a big step in the right direction.

It just doesn’t matter to me. I’m cheap, so I hate buying sensors every year, but they work so well now, who cares. I have four. If they all four agree, awesome. If they don’t agree, super easy to figure out what’s wrong. It’s just not a big deal to me.

But I have a pretty good handle on CCR at this point.

 

[GiraffeMarineSalvage]

You would be wrong in your assumption.

Do you have more information to share?
By "diving beyond the safe capacity of the combination of team/diver/equipment at a given moment in time" I broadly include the equipment not being right for the dive that was dove and would consider that human error as opposed to a fault of the equipment (as I said I don't know the specifics and am not even certain which fatality you're referencing, but was it so narrow only safe dive would have been sidemount or with chestmount that needed to be Superman'd with HUD?)

 

[Superlyte27]

Do you have more information to share?
By "diving beyond the safe capacity of the combination of team/diver/equipment at a given moment in time" I broadly include the equipment not being right for the dive that was dove and would consider that human error as opposed to a fault of the equipment (as I said I don't know the specifics and am not even certain which fatality you're referencing, but was it so narrow only safe dive would have been sidemount or with chestmount that needed to be Superman'd with HUD?)

The “leaky valve” on a sidewinder is actually an oriface through a chunk of Ruby. A single droplet of water renders that oriface useless forever and according to KISS has to be sent back for replacement.

You can search SB and see the cause of death, which could have been prevented several ways. 1. Use of a HUD would have saved him 2. A rebreather not prone to o2 failure (and there’s some speculation that he had a roll off, but in my case, it was my 3rd Ruby failure in 6 months) would have saved him. 3. A controller like Shearwater uses that catches the low PPO2 and fires a solenoid would have saved him. 4. A vibrating handset like Optima and Liberty uses that vibrates when PPO2 gets too low would have saved him.

Counting on something like a “leaky valve” to continue leaking without a HUD just seems like a stupid way to die. At least with ECCR you can hear a solenoid fire. You can even distinguish between the two different sounds of a solenoid firing with oxygen and without oxygen.

 

[211ratsbud]

I

You can search SB and see the cause of death, which could have been prevented several ways. 1. Use of a HUD would have saved him 2. A rebreather not prone to o2 failure (and there’s some speculation that he had a roll off, but in my case, it was my 3rd Ruby failure in 6 months) would have saved him. 3. A controller like Shearwater uses that catches the low PPO2 and fires a solenoid would have saved him. 4. A vibrating handset like Optima and Liberty uses that vibrates when PPO2 gets too low would have saved him.

I constructed a MCCR with 1. HUD (nerd), 2. Needle mav (not prone to falling), 3. ( No solution there except that you can set the needle mav for really long slow decay), 4. Petrel 3 analog.

Still full attention is required

I've played with the vibrating alarm which is truly obnoxious when it needs to be. It warns currently if my ppo2 is .69 or below (arbitrary for the most part). I've used it with alarm values of 1.1. forcing engagement. it's definitely a nice feature. If someone doesn't prefer it they can disable it.

 

[GiraffeMarineSalvage]

The “leaky valve” on a sidewinder is actually an oriface through a chunk of Ruby. A single droplet of water renders that oriface useless forever and according to KISS has to be sent back for replacement.

You can search SB and see the cause of death, which could have been prevented several ways. 1. Use of a HUD would have saved him 2. A rebreather not prone to o2 failure (and there’s some speculation that he had a roll off, but in my case, it was my 3rd Ruby failure in 6 months) would have saved him. 3. A controller like Shearwater uses that catches the low PPO2 and fires a solenoid would have saved him. 4. A vibrating handset like Optima and Liberty uses that vibrates when PPO2 gets too low would have saved him.

Counting on something like a “leaky valve” to continue leaking without a HUD just seems like a stupid way to die. At least with ECCR you can hear a solenoid fire. You can even distinguish between the two different sounds of a solenoid firing with oxygen and without oxygen.

Thanks for elaborating. To me the main causative factor was failing to diligently taking responsibility for knowing PPO2, which as you note would be made easier with #1, which prevented timely recognition of #2, consequences of preceding did not have #3 as "parachute," and #4 might have been helpful assuming diver didn't have on coldwater wetsuit/dry suit, and #5 critical gear needs diligent design and maintenance whether it's a O2 sensor, leaky valve, or solenoid (personally I could see quality needle valves eventually replacing fixed leaky valves on vast majority of mCCRs but believe mCCRs/hCCRs will continue to have a strong market position in rebreather diving long into the future..).

 

[Superlyte27]

Thanks for elaborating. To me the main causative factor was failing to diligently taking responsibility for knowing PPO2, which as you note would be made easier with #1, which prevented timely recognition of #2, consequences of preceding did not have #3 as "parachute," and #4 might have been helpful assuming diver didn't have on coldwater wetsuit/dry suit, and #5 critical gear needs diligent design and maintenance whether it's a O2 sensor, leaky valve, or solenoid (personally I could see quality needle valves eventually replacing fixed leaky valves on vast majority of mCCRs but believe mCCRs/hCCRs will continue to have a strong market position in rebreather diving long into the future..).

It doesn’t matter what thermals you have on, you can feel the vibration of the handset. I doubt you’ll see many more hccr or mccr in the future than they’re are right now. I think the trend is actually moving the opposite direction. Even KISS is building an ECCR rebreather now.