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

[Hiszpan]

I think @stuartv and @beldridg give a credible explanation of what might have happened. I base my opinion on the fact that he has had a 26% in his tanks while labeled them 24% and used 24% on his dive computer. I think it was not an analyzing error or his unintentional mistake. I think he did that on purpose to dive a conservative setting vs what he really had in tanks, to give himself extra buffor of security at deco (his computer would have showed him more deco obligation as he in reality had to do, because his computer was thinking he is inhaling more Nitrogen.) That is a common practice in OC if the depth of the dive presents no danger of pO2 being the curtailing factor of such practice. Therefore one has to ask - would he do both, consciously plan a gas too hot for his intended dive AND trick his computer to allow him go even deeper on that gas than he should?

 

[flymolo]

I think @stuartv and @beldridg give a credible explanation of what might have happened. I base my opinion on the fact that he has had a 26% in his tanks while labeled them 24% and used 24% on his dive computer. I think it was not an analyzing error or his unintentional mistake. I think he did that on purpose to dive a conservative setting vs what he really had in tanks, to give himself extra buffor of security at deco (his computer would have showed him more deco obligation as he in reality had to do, because his computer was thinking he is inhaling more Nitrogen.) That is a common practice in OC if the depth of the dive presents no danger of pO2 being the curtailing factor of such practice. Therefore one has to ask - would he do both, consciously plan a gas too hot for his intended dive AND trick his computer to allow him go even deeper on that gas than he should?

how would "giving himself an extra buffer (of 2%) on deco" account for the fact he toxed on the bottom? these theories are getting wildly speculative

 

[Whitrzac]

I think @stuartv and @beldridg give a credible explanation of what might have happened. I base my opinion on the fact that he has had a 26% in his tanks while labeled them 24% and used 24% on his dive computer. I think it was not an analyzing error or his unintentional mistake. I think he did that on purpose to dive a conservative setting vs what he really had in tanks, to give himself extra buffor of security at deco (his computer would have showed him more deco obligation as he in reality had to do, because his computer was thinking he is inhaling more Nitrogen.) That is a common practice in OC if the depth of the dive presents no danger of pO2 being the curtailing factor of such practice. Therefore one has to ask - would he do both, consciously plan a gas too hot for his intended dive AND trick his computer to allow him go even deeper on that gas than he should?

Your opinion is wrong. For the simple reason he was diving a rebreather.

 

[tursiops]

That is a common practice in OC if the depth of the dive presents no danger of pO2 being the curtailing factor of such practice.

It is NOT a common practice in technical diving; you try not to lie to your computer.
Especially when you are on a CCR.

 

[iarf]

I think @stuartv and @beldridg give a credible explanation of what might have happened. I base my opinion on the fact that he has had a 26% in his tanks while labeled them 24% and used 24% on his dive computer. I think it was not an analyzing error or his unintentional mistake. I think he did that on purpose to dive a conservative setting vs what he really had in tanks, to give himself extra buffor of security at deco (his computer would have showed him more deco obligation as he in reality had to do, because his computer was thinking he is inhaling more Nitrogen.) That is a common practice in OC if the depth of the dive presents no danger of pO2 being the curtailing factor of such practice. Therefore one has to ask - would he do both, consciously plan a gas too hot for his intended dive AND trick his computer to allow him go even deeper on that gas than he should?

Diving CCR, assuming a setpoint is held, any 2 nitrox diluent mixes will present identical ongassing and identical decompression schedules on a given model.

There's a lot of wild speculation in this thread.

 

[Tracy]

That is a common practice in OC if the depth of the dive presents no danger of pO2 being the curtailing factor of such practice.

No, it isn't.
And it shouldn't be.
I'm not sure where you learned it, but it is wrong. If you give your computer bad information, it will in turn give you bad information back.
Maybe you are referring to recreational single tank nitrox diving, but that isn't what he was doing.
Even that is bad practice, if you want conservatism, you can change it in your computer settings, you don't have to give it bad information.

I remember inputting incorrect helium contents into computers back when some of the algorithms had a massive helium penalty. But that was considerably different than inputting incorrect oxygen information.

 

[Vicko]

I think @stuartv and @beldridg give a credible explanation of what might have happened. I base my opinion on the fact that he has had a 26% in his tanks while labeled them 24% and used 24% on his dive computer. I think it was not an analyzing error or his unintentional mistake. I think he did that on purpose to dive a conservative setting vs what he really had in tanks, to give himself extra buffor of security at deco (his computer would have showed him more deco obligation as he in reality had to do, because his computer was thinking he is inhaling more Nitrogen.) That is a common practice in OC if the depth of the dive presents no danger of pO2 being the curtailing factor of such practice. Therefore one has to ask - would he do both, consciously plan a gas too hot for his intended dive AND trick his computer to allow him go even deeper on that gas than he should?

That's a practice left over from old aladins and similar computers where you could not change conservatism, but you could change your mix. It should have died out in the 80-s or 90-s but somehow people keep doing it.
And on a rebreather that is constantly analysing the gas you are breathing does absolutely nothing.

 

[Nitrogenius]

Mostly, yes. Both tanks were 26/00, but mis-analyzed to 24/00. Computer was set to 24/00, so no reason to believe it was a simple switchup of tanks. AFAIK, members of the team have confirmed they did not know about the mix, and that they were diving with Helium (and lower PO2) at those depths. Check out the Human Diver Blog and the NSS-CDS report.

Thanks for the links.. This is very helpful!

 

[lermontov]

"I'm going to do a 130 foot dive to stage some bottles. I'll use EAN24 for that. It's not deep enough to need helium." He prepared his cylinders and his computers based on that.

Then, time passed. In his mind, his cylinders/gear were all ready to go. Then, somebody said "hey, can you also do a quick bounce and stage these additional cylinders at 190 while you're in?"

i doubt this is an accurate account, according to the report the dive plan was established from the get go
you dont ad hoc a dive if your supposed to be acting as safety diver for divers 1 and 2 that were going to 225' and possibly 300'.

"At 1112HRS Diver 3 and the Victim entered the spring to set stage bottles at depths of 130 ffw, and 190 ffw. Diver 3 and the Victim, along with other divers setting shallower stage bottles were also acting as safety divers for the deeper team (Divers 1 and 2). Their estimated run time was 30 minutes."

My guess is it was noted and timed pretty carefully due to the numbers of diver in the water and the restrictions that needed to be navigated, we need to give the team credit for that surely

what would be of interest is what was diver 3 using as gas and what was his controller set at, this would establish if the plan to go to 190' was understood by eric and the gas that diver 3 took was suitable for the dive and if so what was it?

Ironically the gas (190') he was carrying could have been used to help him, but due to stress and narcosis he probably didnt think of it

 

[rjack321]

Ironically the gas (190') he was carrying could have been used to help him, but due to stress and narcosis he probably didnt think of it

If it had been used as a diluent instead of the onboard nitrox we almost for sure wouldn't be having this conversation at all