Virginian diver dead at 190 feet - Roaring River State Park, Missouri

[flymolo]

Fair enough, and my apologies for the way I expressed myself.

The post I was responding to mentioned tradeoffs to using a best mix approach. In the specific example I gave, the tradeoff is not big, for one short-ish dive.

My underlying point remains. I cannot see any negative to standardizing a project on the specific gases that are best for that project, rather than limiting yourself to a generic list of "Standard Gases". On the other hand, there is potential for negatives (though possibly not huge) when choosing to limit your choices to a generic list.

Example that maybe better illustrates my point: If you go to do recreational wreck dives out of Morehead City, North Carolina, the shops there bank EAN30, not EAN32 - though EAN32 is a Standard Gas and EAN30 is not. For the specific circumstances there, standardizing on EAN30 is better.

Similarly, ANY given project may have specific gases that are better for that project than the ones in the generic Standard Gases matrix.

I don't think it makes sense to turn this thread into a referendum on standard gasses.

 

[Bierstadt]

Indeed not. It's a reminder about not diving with horribly inappropriate gas mixes, safety margins, the narcotic effect of CO2, checking mixes during your buddy check, and including gas mix checking in team SOP. These are not things unknown to us and are not things anyone should die because of; they have been writ in blood too many times.

 

[tursiops]

Indeed not. It's a reminder about not diving with horribly inappropriate gas mixes, safety margins, the narcotic effect of CO2, checking mixes during your buddy check, and including gas mix checking in team SOP. These are not things unknown to us and are not things anyone should die because of; they have been writ in blood too many times.

Unfortunately, "You can't tell ME what to do!" and "I've never had a problem!" will always cause it to keep happening.

 

[hehatemefrisbee]

Indeed not. It's a reminder about not diving with horribly inappropriate gas mixes, safety margins, the narcotic effect of CO2, checking mixes during your buddy check, and including gas mix checking in team SOP. These are not things unknown to us and are not things anyone should die because of; they have been writ in blood too many times.

This seems pretty straightforward! I cannot understand how it wasn't checked prior to them diving, and how more stringent safety measures pre dive were not adhered to. I am a basic ass recreation diver and my dive buddy and I know to check each other's gear because that's just what you do

 

[lermontov]

Unfortunately, "You can't tell ME what to do!" and "I've never had a problem." will always cause it to keep happening.

The GUE code seems to have a better handle on this, if it works for them on a large scale it should/could work in smaller situations like this. Maybe thats the appropriate model for a exploration model with large numbers. What did they do say in Pearce resurgence trips?

Commercial diving has similar strict protocols I suspect

disclosure- Im not a GUE adherent

 

[formernuke]

No need to really get into code or standard gassed etc, though might help.

Just stay with the basics recreational nitrox, 1.4 PPO2 for OC, rebreather I guess is 1.0 or 1.1 for diluent gas PPO2 and dive 1.3.

Doesn't get any simpler than that.

 

[DOBY]

No need to really get into code or standard gassed etc, though might help.

Just stay with the basics recreational nitrox, 1.4 PPO2 for OC, rebreather I guess is 1.0 or 1.1 for diluent gas PPO2 and dive 1.3.

Doesn't get any simpler than that.

Plus set END to 100ft.

 

[rjack321]

thats my reading of it too. The question I have though, and it comes back to the SOP systems they employed, is what was the rationale for this mix? and was it an approved choice as per the management of the project? was it a case of group think? (or Abilene paradox as has been mentioned before )or the more experienced influencing the less and nobody questioned it?

From one of the team members. Apparently, the deceased's gas choices and whether he was supposed to be offboarding another dil with the 24-26% as a deco BO mix is all a complete mystery to the project team, his buddy and the surface manager. Take away from this what you will (ps not my heart like here)

 

[L13]

Choosing not to use HE for a short setup dive was his choice. Everyone else on the team was using mixes with HE in them.

How about using a gas to rich for the dive.

The lack of HE is as important as the excess O2. Even if the gas had not been to rich, without HE, it would have been too narcotic and too dense.

 

[rjack321]

The lack of HE is as important as the excess O2. Even if the gas had not been to rich, without HE, it would have been too narcotic and too dense.

To me, the intended 24% is a very odd nitrox mix that almost nobody just makes up unintentionally. And both cylinders having the exact same analysis suggests that it was not a case of a different nitrox being topped with air. The 24% sure seems intentional. It's also 1.6 ppO2 at the planned depth of the last bottle drop at 190ft. The 26% is a consistent error which I suspect is probably analyzer related.

So on the whole, my guess is the lp50s were his BO/deco gas. I suspect there was supposed to be a different offboard source of dil. But Eric plugged in the wrong diluent source at the start or forgot to switch diluent sources - probably by accident. Project stage bottles can have lots of QC6s on them and sidemount CCRs are partly built in the water and there are few if any QC6 /gas change protocols outside of the RB80 community - and one reason why SM CCRs are highly specialized tools that don't conform to standard CCR build & splash checklists. Lots of loose hoses around with QC6s on the ends and no established team switch protocols is a recipe for plugging in the wrong one.

Unfortunately, the offboard dil issue is not part of the deceased gear inventory, accident narrative, or report. And the dive team is silent on how this project and the gas plans were organized. So we'll never know more unless witnesses are compelled to testify under oath or something extreme like that.

My guess is only a guess, but not realizing which gas was actually plugged in, getting extremely narced during the descent with a modestly high workload of bottles, some urgent panicky punching of both MAV buttons unable to comprehend why the ppO2 wasn't dropping. This is an accident that could happen to others - and almost did only a few scant months before.

I would not be so quick to judge the deceased as some kind of narcosis junky for diving 24-26% dil at 190ft - I don't think that was the case.