Deep, Deeper, Freakin' Deep!

[Rick Inman]

Hydra 8
Depth : 500 / 520 / 534 metres (1988) (Operation at sea - world record)
Divers : Th. Arnold - S. Icart - J.G. Marcel Auda - R. Peilho - P. Raude - L. Schneider

Sorry if this is the wrong forum for this question, but I'm looking all over and I can't find the standard DIR mix for this dive.

 

[RonFrank]

How pointless.

Sounds like an incredible waste of time, and money not to mention the risk involved.

My cuz routinely hits 2000ft, but she's no fool. She does so for scientific exploration in a Johnson Sea Link or similar submersible!

 

[Tigerman]

Im not sure how the depths people work at are today, but there approxmately 250 "north sea divers" who conducted dives in the north sea between 1960 and 1980 that supposedly where as deep as 3-400 meters.

Problem is of course that according to some statistics 20% of these divers died between the age of 20 and 50 years, while the normal rate of death for that age group in the general population is 4-5%.
Also Haukeland university hospital has estimated that 98% of the divers in question has gotten their quality of life reduced from this career and 65% of them is diagnosed with PTSD.
None of the north sea divers has retired at the retirement age, which is 67 years.

 

[DeepSeaDan]

How pointless.

Sounds like an incredible waste of time, and money not to mention the risk involved.

My cuz routinely hits 2000ft, but she's no fool. She does so for scientific exploration in a Johnson Sea Link or similar submersible!

....those still working at great depth are VERY well paid for their skill, & they do some extraordinary work down there, the kind of work experience that must be lived to be fully appreciated & understood. The experimental work done by Comex, Duke & many others before them & since have greatly contributed to the safety & well-being of saturation divers - all divers in fact; their work has increased our knowledge of human physiology u/w, and make no mistake...

...all of the recreational diving communities knowledge of mixed gas diving comes directly from the work / experiences of the military & commercial diving worlds...

...so a little thanks & a wee drop of respect would not be unreasonable.

DSD

 

[ianr33]

Sylvia set the "solo women's record" in a Jim Suit that was tethered to a submersible. She later broke the women's record in the Deep Rover vehicle at 1,000 meters.

Sylvia in JIM suit, note umbilical and submersible in the background.

Sylvia in the Deep Rover submersible during training dives off the California Coast.
Note the EDGE decompression computer I put on the right manipulator arm as a joke.

I would recommend she take Fundies.

Her trim is just horrible

 

[TimAZ]

Well for a surface consumption rate (SAC) of 0.6 cubic feet per minute and 15 breaths per minute there are .04 cubic feet per breath at the surface. So to breath a 80 cu ft cylinder down in one breath the ambient pressure would have to be increased by a factor of 2000 (80 cu ft/.04 cu ft/breath). Since there is one atmosphere at the surface, and 33 fsw (or 10 msw) for each additional atmosphere you would have to be almost 66,000 feet down (or 20,000 meters). But the ocean is not that deep. But...if you dug a 6 mile deep mine shaft at the deepest place in the ocean and filled it with salt water you could breathe an 80 in one breath.

Of course the ambient pressure would be 30,000 psi (or 203 MPa) so an aluminum cylinder might well fail. Maybe with steel (yeah right).

You go first.

But since a tank is "empty" when it reaches ambient pressure, wouldn't you get that one breath at half that depth?

 

[Mr Carcharodon]

But since a tank is "empty" when it reaches ambient pressure, wouldn't you get that one breath at half that depth?

I am not sure I follow you. How did you arrive at half that depth?

There would be a number of things going very wrong at that depth. First off as has already been pointed out if the pressure outside the tank is greater than the pressure inside the tank no gas is going to come out. The tank, regulator and certainly all the elastomer hoses would be crushed by the ambient pressure. And this does not address the physiological issues with those sorts of depths. The general assumption is that fluid filled tissue is incompressible but that is an approximation based on an imbedded assumption about how high the ambient pressure can be.

How can anyone not want to explore the abyss and find out what is down there? As a species we have just skimmed the surface. I would think we could solve the engineering issues associated with deep exploration but I expect there probably are physiological issues that are not yet understood or perhaps even solvable. The work that has already been done with heliox mixes and submersibles are a start. But I wonder what it would take to push the limits to 2000 m or 3000 m and beyond.

Anyway in two weeks I will be doing a blackwater dive with the bottom several thousand feet below, off the Kona coast, waiting to see what comes up at night. But wouldn't it be nice to push down just a little deeper. To see the creatures of the abyss, the creatures of the night, in their world. But it is our world too so why do we not know them?

 

[Lucy's Diver]

Navy Experimental Diving Unit

These guys basically experiment on people. They press guys to 2000 fsw or more. The pool under that chamber is pressed as well so they do dives in it at that pressure.