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

[L13]

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.

Totally agree with this point!

 

[PfcAJ]

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.

30% can be a standard gas if your team chooses it to be so.

GUEs standard gases different the WKPPs standard gases which are different from say Monroe County sheriffs standard gases. But the strengths of having the standard gases are there in all cases.

 

[rjack321]

30% can be a standard gas if your team chooses it to be so.

GUEs standard gases different the WKPPs standard gases which are different from say Monroe County sheriffs standard gases. But the strengths of having the standard gases are there in all cases.

Exactly "standard gases" are a bit of a "when in Rome" kinda thing. For the wrecks of Bell Island Newfoundland, the sand is right around 130ft. Not many people actually swim along the sand, but the dive shop has standardized on 28% so it's feasible if you wanted to be that deep and there's generally little risk that their clients will be breaking MODs. Supplying 32% would not really extend anyone's bottom times cause people get too cold before they run out of NDLs anyway. But 28% is an improvement over air and acts as a safety factor to minimize the "unwarranted DCS" hits that happen rarely. It makes sense in the context and is a reasonable balanced choice for their situation.

Having a standard gas plan with standard BO gases and a standard dil is "normal" for the projects I work on - which aren't as deep as Roaring River but much more remote.

 

[Wibble]

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.

Air top on a 32%?
Mix for 45m/150ft?
Non He mix because He wasn't available?
Non He mix to switch to for deep deco?

Wasn't there so can't double guess. There's many perfectly valid reasons for choosing a gas.

 

[lermontov]

Air top on a 32%?
Mix for 45m/150ft?
Non He mix because He wasn't available?
Non He mix to switch to for deep deco?

Wasn't there so can't double guess. There's many perfectly valid reasons for choosing a gas

can you identify a perfectly valid reason why he would use this gas as dil on the dive in question?

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.

wasn't his computer was set to 24% so it seems it was intentional

 

[rjack321]

wasn't his computer was set to 24% so it seems it was intentional

I don't believe a trimix diver would intentionally plan to use 24% as dil at 190ft in a cave. I mean you "could" attempt to breath it down by shutting off the O2 add and descending slowly. Basically turning your CCR into a nitrogen generator. Helium was available to the rest of the project divers/team.

Alternatively you can operate under the assumption that he meant to change diluents or use an alternative helium containing dil, also with a lower O2 content. But for whatever reason was distracted or failed to confirm the switch. This is similar to the WKPP fatality about 5 years ago with the failed switch from the 70ft bottle shallow to a deeper trimix and he also toxed at ~150ft+. And similar to Gus' use of the wrong dil in Roaring River just a few months prior. There is considerable precedent for this kind of mistake.

 

[Vicko]

Well, once you have a bunch of experienced and "experienced" divers who are also friends in a group you sort of stop second guessing them. That's why 3 people, so far, used wrong diluents on the same project.


I hate diving with really good divers because it leads me to act like them, and I'm sure I'm not the only impressionable diver in the world. So if I was diving with some of the most famous cave divers in the world and I accidently brought the wrong dill I could see myself doing something stupid to not look like a bad diver and stop the project for the day. I can see myself not checking my dill po2 at depth, not making sure the correct gas is plumbed in or not calling the dive when I notice something actually is wrong.

 

[Wibble]

can you identify a perfectly valid reason why he would use this gas as dil on the dive in question?

wasn't his computer was set to 24% so it seems it was intentional

I wasn't there and I cannot possibly double guess what happened. Merely stated that there are many perfectly valid reasons for choosing or using 24% gas.

 

[L13]

...
I hate diving with really good divers because it leads me to act like them, and I'm sure I'm not the only impressionable diver in the world. So if I was diving with some of the most famous cave divers in the world and I accidently brought the wrong dill I could see myself doing something stupid to not look like a bad diver and stop the project for the day.

...

I have the same problem, but at the same time I love how much I can learn from them. In the end I love it more than I hate it, but I have to take extra care to check my ego in those situations.

It's kind of ironic, no matter how good or bad the other diver is, they are both a hazard and a resource that needs to be understood. An exceptional diver is an exceptional resource, but also an indirect hazzard.

 

[PfcAJ]

Well, once you have a bunch of experienced and "experienced" divers who are also friends in a group you sort of stop second guessing them. That's why 3 people, so far, used wrong diluents on the same project.


I hate diving with really good divers because it leads me to act like them, and I'm sure I'm not the only impressionable diver in the world. So if I was diving with some of the most famous cave divers in the world and I accidently brought the wrong dill I could see myself doing something stupid to not look like a bad diver and stop the project for the day. I can see myself not checking my dill po2 at depth, not making sure the correct gas is plumbed in or not calling the dive when I notice something actually is wrong.

I promise you, you will gain far more respect by calling attention to a problem than you would by hiding it.

You will 100% absolutely be blackballed forever from just about any respectable project if you are dishonest and/or willingly violate standards and procedures.