Rob Stewart and Third Dive

[nadwidny]

CO looks 'fine' (much below 10 ppm). The CO2 in the 50% probably wouldn't be noticeable at deco depths ≤20m ('1800ppm' equivalent at 3x pressure?). Might be common in nitrox membrane systems that concentrate heavier ambient gases (O2, CO2, argon)

Is there any precedent for deep commercial/sat divers to pass out on deck after rapid ascents that skip in-water Buhlmann decompression? I was under the impression they just strip down and walk themselves into a chamber. But maybe you don't here about the others.

No. The CO is not fine. There should be zero. None. While the values are within the crappy limits that CGA allows, the values also indicate there is a problem with the supplied air. I worked in a lab that dealt with this sort of thing and I've run thousands of samples of breathing air and other breathing gases. The numbers posted are not good. There is something going on with the fill system and I would expect a strong likelihood that a deeper analysis would find other issues.

And the CO2 is also not fine. The issue with the fatality and all the other stuff that went on probably isn't related to the breathing gas, but I am alarmed at what the Navy found out. Whoever filled those tanks has one shisty fill system. I hope they aren't around anymore.

 

[Alex Ouroboros]

10/50 as main dil tells me yet another massive negative about this destructor. Not only lazy but thick as **** too.
Was the planned depth 80m? (84 goes the bailout even at 1.4) erm no.
Could, sorry, should have done that all with non hypoxic gasses, I realise these points may or may not have made any difference to this days diving outcome but an instructor that doesn’t give a damn about proper gas matching for planned dives is giving the reaper an opportunity to come knocking one day, I also don’t see how an instructor can feel they have given their student the correct reinforcement of its importance, just makes me think they will be lazy in other aspects too, (and that’s based on personal experiences)

Sorry for the rant folks.

 

[justinthedeeps]

Honestly none of these individual details explain or prevent this accident.
It's going to be Human Factors.

A lot of heroes, very talented experienced people have joined the ocean and not come back. Many of them knowingly doing things beyond accepted limits.

Best if someone--ideally everyone--in the team or surface support remains well below their limits. At minimum, this is the instructor or guide.

Modern agencies are very strict and observant on instructor protocol now.

 

[Capt Jim Wyatt]

Modern agencies are very strict and observant on instructor protocol now.

Heh--at least they pay lip service.

 

[rjack321]

I hope they aren't around anymore.

Teaching CCR the Libyan way as continuing education in the US federal penitentiary perhaps?

 

[justinthedeeps]

No. The CO is not fine. There should be zero. None. While the values are within the crappy limits that CGA allows, the values also indicate there is a problem with the supplied air. I worked in a lab that dealt with this sort of thing and I've run thousands of samples of breathing air and other breathing gases. The numbers posted are not good. There is something going on with the fill system and I would expect a strong likelihood that a deeper analysis would find other issues.

And the CO2 is also not fine. The issue with the fatality and all the other stuff that went on probably isn't related to the breathing gas, but I am alarmed at what the Navy found out. Whoever filled those tanks has one shisty fill system. I hope they aren't around anymore.

While I agree that a <1 ppm CO reading is better than 1.5 ppm--and that it is good to strive for the lowest possible monoxide levels in breathing gases by proper compressor state and appropriate specific filters--this is indeed 'fine' in the context of this discussion. There is no physical, medical or scientific basis by which this would have contributed to the matter of this thread. If what I am reading is correct, the human body produces about this much CO naturally in exhaled breath.

It is of course good to be hyper-aware of carbon monoxide risks, but understanding at what levels there are risks or relevant effects is also a critical part of this awareness.