DIR- Generic Marked stages filled with lower O2?

[RainPilot]

There is no single gas that everyone agrees on that goes into a 100, 120, 150, or even a 200 bottle.

Past 20 and 70, the MOD =/= and particular gas although it's usually just no more than 2 options. 120 is 35/25 for some folks and 30/30 for others for instance. 150 is 21/35 for some and 25/25 for others. 190 is usually just 21/35... The disparities are real.

I feel like these "different MOD for same gas" issues could be easily fixed by us all standardizing on a meaning. My take is that MOD is Max Operating Depth with a 1.6 PO2, with TOD being Target Operating Depth with a PO2 of 1.2 or whatever the plan requires.

I mark MOD, even on bottom stages, since if I have a 120' marked tank, even if I plan to switch shallower, that will not lead to a safety concern, whereas in an emergency someone looking at my tank will know that it is switchable up to the marking depth, which gives them and me more options when needing to use that gas for an ascent vs planned bottom stage.

The neck tape with analysis is for me to use, the side / bottom markings are for everyone else to verify or for emergency (eg I hand over a bailout to a diver with lost gas, they can immediately compare the depth to the MOD sticker and make a judgement on what they want to do with it. That of course means that the MOD must be correct for the gas in that tank.

 

[MarkA]

21/35 backgas with up to 15 min deco on 32%. I think it's a nice stepping stone to Tec 1

Interesting that the deco gas is 32% instead of 50%.

Are the cylinders and regulators in Alsace M26 for nitrox?

 

[iliketopetsharks]

Interesting that the deco gas is 32% instead of 50%.

Are the cylinders and regulators in Alsace M26 for nitrox?

For dives in this range, 50% doesn't make much of a difference compared to 32% which is easier to source.

M26? Ha haha hahahaaaa. No. I think i've seen like 2 cylinders with M26 valves in my life. Both were collecting dust in a corner of a dive shop....

 

[PfcAJ]

I mean, i don't disagree, but could you elaborate a bit further?

It’s a pointless class.

If you aren’t ready for t1, then you simply aren’t ready to tech dive.

It’s full on nonsense like 32% as a single deco gas, and all these subsequent issues with bottle marking.

It’s just a money grab.

 

[eightytwenty]

Permanently marked bottles was something that Trey would always harp on pretty hard. I remember talking to Todd Kincaid, and he mentioned that him and Jarrod used to do the masking tape and sharpie MOD labels, and George would rag on them constantly for it. Eventually, as Todd told it, someone died using temporary MOD labels, and suddenly Jarrod and him realized the cost of a couple more bottles was a whole lot cheaper than their lives.

I know that anecdote isn't completely on topic, but it stands to show that bottles should be permanently marked if it's at all possible. That being said, filling your permanently marked bottles with gases that shouldn't be in them is total weenery. Not that hard to own a 100 bottle for 32% and a 70 bottle for 50%, especially considering the bad time you'll have if you bring a lower FO2 gas on a dive with real deco. I also can only imagine that if you don't have a 100 bottle or whatever, you could borrow one from someone who does...

I personally value mine and my teammates lives higher than the $100 or so it costs for an Al80 and stage rigging. If someone doesn't see it that way, I don't want to be in the water with them.

 

[NothingClever]

I know that anecdote isn't completely on topic…

I think it’s precisely on topic.

That being said, filling your permanently marked bottles with gases that shouldn't be in them is total weenery.

Concur.

 

[steinbil]

I personally value mine and my teammates lives higher than the $100 or so it costs for an Al80 and stage rigging. If someone doesn't see it that way, I don't want to be in the water with them.

I wholeheartedly agree with the sentiment, even though an AL80 stage-rigged is $600 here.

 

[PfcAJ]

Permanently marked bottles was something that Trey would always harp on pretty hard. I remember talking to Todd Kincaid, and he mentioned that him and Jarrod used to do the masking tape and sharpie MOD labels, and George would rag on them constantly for it. Eventually, as Todd told it, someone died using temporary MOD labels, and suddenly Jarrod and him realized the cost of a couple more bottles was a whole lot cheaper than their lives.

I know that anecdote isn't completely on topic, but it stands to show that bottles should be permanently marked if it's at all possible. That being said, filling your permanently marked bottles with gases that shouldn't be in them is total weenery. Not that hard to own a 100 bottle for 32% and a 70 bottle for 50%, especially considering the bad time you'll have if you bring a lower FO2 gas on a dive with real deco. I also can only imagine that if you don't have a 100 bottle or whatever, you could borrow one from someone who does...

I personally value mine and my teammates lives higher than the $100 or so it costs for an Al80 and stage rigging. If someone doesn't see it that way, I don't want to be in the water with them.

You don’t even have to go back to the George days. Wrong gas in wrong bottle continues to kill people nowadays.

 

[rddvet]

You don’t even have to go back to the George days. Wrong gas in wrong bottle continues to kill people nowadays.

People quickly forget about the most noteable example in recent years of the guy in Ginnie on Oxygen cause he didn't analyze. (I'm obviously simplifying the story). But people get a little butt hurt and reactive when you bring it up because he was a well-liked dude. But also a dude who was known for some stupid stuff like what got him killed. You can be both a nice guy and a complacent idiot that kills yourself and endangers others at the same time.