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

[rjack321]

You think the made the switch at depth or had the wrong gas plugged in from the start of the dive? IIRC in the report it say he didn't have a stage on him... if he didn't have a stage he couldn't have made the wrong switch. If he dropped the stage, his switch to nx would have been deliberate.

My understanding he was assigned to deploy safety bottles at 190ft. So yes he would have had gases other than the 2x 50s with 24/26% in them. Those dropped safety bottles would almost certainly have had QC6 males on them.

He toxed on the way down, not the way up. And if he had used offboard dil on the way down, just plugging in his EAN at the bottom wouldn't change his loop contents. In fact, he probably wouldn't have injected any dil into his loop for the remainder of the ascent and we never would have heard about this setup dive.

 

[rjack321]

There are zero good reasons to have a tank of 26 or 24…

You'd be surprised how many people advocate ppO2 of 1.6 as a deep BO since you "won't be down there very long"

 

[berndo]

He toxed on the way down, not the way up. And if he had used offboard dil on the way down, just plugging in his EAN at the bottom wouldn't change his loop contents.

Yeah, good point.

 

[rjack321]

Label the cylinder. Trace the hose. Treat it like any second stage with different gases.

Unfortunately this is rarely done on the sidewinder in particular. 1) due to the location of the QC6 female and 2) from the way this unit is taught.

 

[crofrog]

You'd be surprised how many people advocate ppO2 of 1.6 as a deep BO since you "won't be down there very long"

Sure there are a lot of bad reasons.

 

[rjack321]

Sure there are a lot of bad reasons.

And exactly how many times have you chosen a CCR bailout gas again?

 

[crofrog]

And exactly how many times have you chosen a CCR bailout gas again?

Ah the comeback of someone who can not refute the point and resorts to an ad hominem attack instead.

On a real dive answer is 0, but choosing a gas is an academic exercise done well before you get in the water so let me know how that’s relevant.

As far as good reasons to choose weak nitrox Is it the fact that it’s more narcotic, or had a higher gas density that makes it a good choice?

But I could be wrong so what are some of the good reasons to choose it as your bailout gas?

 

[DOBY]

Choosing a deep BO with a pO2 above 1.4 might be ok while wreck diving where the vis is good enough to be able to ascend a couple of ata’s and still see the wreck to get to the up line. But it’s not a good idea on low vis wrecks (like the Great Lakes) or in a cave where you might be at a high pO2 for awhile…….IMHO.

 

[lermontov]

Choosing a deep BO with a pO2 above 1.4 might be ok while wreck diving where the vis is good enough to be able to ascend a couple of ata’s and still see the wreck to get to the up line. But it’s not a good idea on low vis wrecks (like the Great Lakes) or in a cave where you might be at a high pO2 for awhile…….IMHO.

To what advantage?
The thing I like about ccr over OC is that you have a lot more time and options to resolve problems, the issue with choosing a high po2 BO is it takes away those advantages and puts you under more stress in what could be an already stressful situation. It can also reduce the option using it as an offboard dil.

If you are classifying it as a deep BO then you no doubt have a deco gas somewhere and youll have calculated a worse case scenario wouldn't you?

 

[DOBY]

To what advantage?
The thing I like about ccr over OC is that you have a lot more time and options to resolve problems, the issue with choosing a high po2 BO is it takes away those advantages and puts you under more stress in what could be an already stressful situation. It can also reduce the option using it as an offboard dil.

If you are classifying it as a deep BO then you no doubt have a deco gas somewhere and youll have calculated a worse case scenario wouldn't you?

I totally agree with you. Was just pointing out why some wreck divers might do it is all. Didn’t say I agree with it.

As I said in my post “it’s not a good idea.” i.e: to use a deep BO with a pO2 above 1.4. I tend to keep on-board Dil at a pO2 at 1.0 ata and OC BO at 1.2 ata max. And of course you would be carrying a shallow deco gas.