Diving air to 60m

[Tchau]

60m with good viz and conditions and warm water is very different than cold and dark. The former I’d be ok with if for a particular reason. The latter - **** that. Can’t see **** anyhow after 30m so there would have to be a pretty good reason for me.

I’ve been totally composed at depth in lovely water. I’ve equally been freaked out much shallower in cold dark current wishing it was time to go up.

You are absolutely right.

 

[John Bantin]

Hey John, how would you plan this dive than... in this dark, cold water quarry to 60 (or maybe 70m)? Would you go OC or rebreather, would you dive air or trimix? What would you do?

And have you ever done deep(ish) dives on a single tank with air in a cold water quarry. When you did...where you lucky or competent?

Of course underestimation of risks and probably inexperience coupled with equipment failure (bcd) caused the chain of events that made this a disaster. But if the BCD trigger didn't happen, for all we know they could have made a "normal" bounce dive to 60m on air with a single tank, and come out "heroes", thinking they were really very experienced and good divers! Deep air is not dangerous, diving a single tank to that depth is not dangerous... come with us... we do it all the time!

Yes, I have made many dives in quarries with water at 4°C. I have tested regulators at depth in northern Sweden in February and dived under ice in Finland. I dived prototype Prisms and Inspirations in the early '90s, before they went into production. I was lucky in that I was paid to do it - but enough about me.
Last Sunday, I went with my wife and her friend to the same place (Chepstow) to check their kit before they went off to dive in US lakes. They used single 12-lire tanks with air and consequently limited their depth to 100-feet (30m). We discovered a slightly leaking drysuit inflator (replaced) and an unreliable BC inflator (replaced). Nobody died. Lucky or competent?

 

[Diving Dubai]

Well, what do you expect diving a stupid gas, at a stupid depth, with a stupid gas volume?

In theory with just a 10min bottom time, with MY SAC the dive to 60m is doable on a single 12l steel, honouring a 60 bar reserve on the surface. Using my wife's ridiculous SAC then a 14min bottom time with the same would be okay

I say theory because that's from the warm and safe position of looking at a planner on my computer (but with known and accurate consumption's etc)

Would I make that dive IRL - Nope!

 

[beester]

In theory with just a 10min bottom time, with MY SAC the dive to 60m is doable on a single 12l steel, honouring a 60 bar reserve on the surface. Using my wife's ridiculous SAC then a 14min bottom time with the same would be okay

Do the math... a 60b reserve on a 12L tank (720bLiter) is not enough reserve to make it up gas sharing with your buddy. Even if your SAC doesn't rise at all and you do a direct to surface ascend without any stops you would be cutting it very very close. With a raised SAC and any form of slow down during ascend you run out of gas.

Before you think I'm talking just as an armchair theorist... i've done a gas sharing ascend from 70m to first gas switch at 21m, trust me 720L was no way enough, and we were calm and in control.

 

[Storker]

Do the math... a 60b reserve on a 12L tank (720bLiter) is not enough reserve to make it up gas sharing with your buddy.

I believe @Diving Dubai was only considering his own gas requirements, and assuming everything goes well.

I think we all agree that that's not healthy gas planning.

 

[beester]

Imagine all the boys sitting around the cabin full of smoke relaxing having a drink telling jokes making a dive plan

and in bursts Jacques, "Merde there's no diving mon'Amies I've just come back from the next century where they
don't do anything, and apparently we cant go diving until someone comes up with an invention to boost helium!"

Funny... Cousteau is mentioned a lot when it comes to deep air diving, however he was also the first to put a limit on the depth for air dives (90m) after the death of Maurice Fargues (GRS). Next they were also one of the first experimenting with trimix and heliox (see conshelf 1, 2 and 3) and the later britannic expedition. Finally they worked together with COMEX, the agency known for their deep saturation dive experiments (hydra).

So I'm quite sure that JJ Cousteau wouldn't be surprised, and would keep up with current technology and scientific understanding, in fact he and his team were evolving all the time, experimenting with different diving gases, different equipment, rebreathers, scooters... unlike some posting on this topic

 

[Kay Dee]

60m with good viz and conditions and warm water is very different than cold and dark.

Totally agree!!! Very VERY different settings. Cold and poor vis would concern me more than just cold and dark, but I'd like to be dialing in the helium long before 60m in either of those conditions.

 

[cathal]

The implication is that air killed. Incompetence kills. Many people should not even be in the water. Air just makes it more difficult. Water kills.

Applying this argument in the context of drunken driving:

The implication is that alcohol killed. Incompetence kills. Many people should not even be in a car. Alcohol just makes it more difficult. Cars kill.

Through constant scientific advances we know that air and depth are an unsafe combination for the vast majority of the diving population. Like anything in life there are the outliers, people whom the rules physiologically do not apply. They got lucky in the gene pool. But it is unwise to adopt safety norms that are only applicable to the outliers. Its the vast majority to whom we should adopt our standards to protect then by default we protect the outliers as well.

 

[Bob DBF]

Next they were also one of the first experimenting with trimix and heliox (see conshelf 1, 2 and 3) and the later britannic expedition.

The US Navy (NEDU) was experimenting with mixed gasses for diving in 1924 and by 1939 was using Heliox gas for divers on the the salvage of the USS Squalus.

The death of Maurice Fargues was in 1947.



Bob

 

[InTheDrink]

Yes, I have made many dives in quarries with water at 4°C. I have tested regulators at depth in northern Sweden in February and dived under ice in Finland. I dived prototype Prisms and Inspirations in the early '90s, before they went into production. I was lucky in that I was paid to do it - but enough about me.
Last Sunday, I went with my wife and her friend to the same place (Chepstow) to check their kit before they went off to dive in US lakes. They used single 12-lire tanks with air and consequently limited their depth to 100-feet (30m). We discovered a slightly leaking drysuit inflator (replaced) and an unreliable BC inflator (replaced). Nobody died. Lucky or competent?

Competent. Tick.
Lucky. Tick.

No man or woman is beyond chance. To think otherwise is a fool’s game.

SB is highly conservative in its views. I take risks that probably wouldn’t go down so well here.

But dying is somewhat arbitrary so just be glad despite the tigers for some reason the god chose not to take you.

Because but for the gods you would not speak. You’re one mother ******* lucky dude. Also competent. Still lucky.