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

[flymolo]

So, he would have been better off on EAN32? I mean, that's a Standard Gas, right?

He used the wrong gas for the dive. You can choose the wrong gas for a dive, whether you are choosing from Standard Gases or not.

He had a process for choosing a suitable gas. Whether the process was a Standard Gas matrix or a Best Mix process is irrelevant. He did not use the process, and that was the problem.

Standard gasses indicate the depth at which the gas should be used as well.

We also don’t know why he chose 24%. Wasn’t there a similar incident at this location where another diver was carrying air as bailout to a similar depth?

 

[tursiops]

Standard gasses indicate the depth at which the gas should be used as well.

We also don’t know why he chose 24%. Wasn’t there a similar incident at this location where another diver was carrying air as bailout to a similar depth?

Hmmm, just narcosis, or narcosis plus oxtox. Tough decision.

 

[formernuke]

Narcossis doesn't cause seizures.

Definitely ox tox. Narcossis was likely a contributing factor though

 

[stuartv]

No it won't. But it does change the mindset behind gas selection. You aren't making trade offs like with a best mix approach, you go down the list until you reach the gas which has a maximum depth below your absolute max depth.

So there is less chance for someone to consider "Perhaps I don't need helium that much."

No system is perfect, but I think that between this accident and the incident with Gus, I am hoping that they've taken a step back to think about ways to make their SOP more fail safe.

Of course you are making trade-offs if you elect to only use Standard Gases. If there is one gas for 150-200 foot dives and you are going to 155 feet, then you are making a BIG tradeoff by using a gas that is suitable for 200 feet.

I would totally expect a project like that to have "standard gases" - but I that does not at mean that they are necessarily Standard Gases.

I.e. Standard Gases is (I think) a pretty well-defined list of depth ranges and mixes. But, on a project like this one, their list of standard gases might work best for their project and yet not match the list of Standard Gases. E.g. if they know they are going to be doing a lot of diving at 170, the project might have a standard gas for the project that is "Best Mix" for 170,

Again, none of that changes what I said. Mistakes happen during blending. All the SOPs in the world won't change the fact that a tank that is supposed to be 18/45 might somehow end up analyzing as EAN26. If the diver is not self-disciplined and wise enough to refuse to dive that tank to 200', then I don't see how an SOP that defines a list of "standard" gases to be used will have any effect on that diver's decision. If "I could easily die from doing that" doesn't stop a person, is "it's against the rules in the SOP" really going to change their mind?

More questions: Was there a Dive Safety Officer (or whatever their title might be) involved in this dive? Did the DSO know what mix Eric was using, and what depth Eric's task would be occurring at? I presume there was at least someone logging diver names and times in and out of the water. Did that logging also include logging what gas(es) the diver was using? The planned runtime? The planned max depth?

 

[kierentec]

Of course you are making trade-offs if you elect to only use Standard Gases. If there is one gas for 150-200 foot dives and you are going to 155 feet, then you are making a BIG tradeoff by using a gas that is suitable for 200 feet.

I don’t want to derail the thread too much, but what do you see the BIG trade offs being between 18/45 and 21/35 for a 155’ dive (assuming you’re talking OC on this point)? We’re talking several minutes of deco…

 

[DOBY]

Did the DSO know what mix Eric was using, and what depth Eric's task would be occurring at? I presume there was at least someone logging diver names and times in and out of the water. Did that logging also include logging what gas(es) the diver was using? The planned runtime? The planned max depth?

Based on comments made here by team members the answers are a hard “NO”. But will happen, moving forward.

 

[Tracy]

Of course you are making trade-offs if you elect to only use Standard Gases. If there is one gas for 150-200 foot dives and you are going to 155 feet, then you are making a BIG tradeoff by using a gas that is suitable for 200 feet.

You mention a big trade off, what is it?
One a simple 30 minute dive to 155' with a standard gas of 21/35 instead of a best mix of 25/30. You would have a whole 4 minutes longer deco obligation.

Personally, I don't see that as a huge tradeoff to not run standard gases. What is the big trade you see?

 

[Whitrzac]

I'm not understanding why you all think standard gases would have made a difference.
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.

 

[stuartv]

I don’t want to derail the thread too much, but what do you see the BIG trade offs being between 18/45 and 21/35 for a 155’ dive (assuming you’re talking OC on this point)? We’re talking several minutes of deco…

You mention a big trade off, what is it?
One a simple 30 minute dive to 155' with a standard gas of 21/35 instead of a best mix of 25/30. You would have a whole 4 minutes longer deco obligation.

Personally, I don't see that as a huge tradeoff to not run standard gases. What is the big trade you see?

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.

 

[formernuke]

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.