Missing sub

[Rod Speed]

But hydrogen cylinders are at a much higher pressure than 400 bar

[Chris Hogg]

Quite. But as has been pointed out by several here, you'd never get the gas out of the bottle to fill the lift bag in the first place. And what's the solubility in seawater at those depths and temperatures of whatever gas you attempted to use. It may all just dissolve.

[Rod Speed]

You would with hydrogen.

Nope.

[Clive Arthur]

Steam? Some sort of pyrotechnics and an insulated balloon?

Metallic Sodium to produce hot H2 on contact with seawater?

[Andrew]

I'm sure I read somewhere that Boeing have already refuted that claim.

[Andrew]

After seeing how F1 car front wings and other appendages made from carbon fibre, disintegrate into fragments on impact, I wonder if there are any recognisable bits of the central tube left.

[John Walliker]

I don't need to because flotation bags are often open at the bottom. John

[John Walliker]

I have never seen a commercial gas cylinder (including hydrogen) at 400bar or more. I'm sure that hydrogen or nitrogen or air could be compressed to such pressures if there was a need that justified the extra cost of the stronger cylinder. (Yes, I do know about critical points.) However, using kerosene or gasoline (petrol) is much easier when buoyancy is needed. John

[Rod Speed]

Then you need to get out more, particularly with hydrogen.

And it doesnt have to be a commercial gas cylinder anyway.

Hydrogen gas cylinders are already MUCH heavier than nitrogen or air.

[Chris Hogg]

Generally described as open bottom parachute lift bags, e.g.

and Lots more out there.

Rod Speed is a know-nothing.

[SteveW]

Usually, the larger ones are at 210 to 230bar, while the medium sized ones are (IIRC from the 1990s) around 160bar.

[Fredxx]

They could be vented to maintain constant volume and hence lift.

And I thought you were a chemist. Nothing to do with bags bursting.

Anyone with the slightest interest in chemistry would know that lithium dissolved in ammonia is the lightest liquid known to man under normal conditions with less than 50% of the density of sea-water.

[Fredxx]

Hydrogen can be stored at pressures of 500 bar. I don't see why that couldn't be applied to other gases apart from perhaps oxygen.

[Fredxx]

Feel free to cite any link of the the solubility of hydrogen at pressures of 400 bar.

I know you'd rather not.

[Rod Speed]

Not feasible with the air bag tearing up to the suface at a hell of a rate

More of your mindless bullshit with that stupid claim about anyone with the slightest interest in chemistry.

Have fun explaining how you get it down there to use it as a lift bag.

[Rod Speed]

700 in fact.

[Rod Speed]

Thats irrelevant given that the hydrogen wouldnt be dissolving as it fills the lift bag which starts uninflated.

[Chris Hogg]

It was a question. I have no idea what the solubility is, high or low.

[Colin Bignell]

I don't blame them. Think of the lawsuits if they claimed any responsibility for the design.

[Andy Burns]

What I read is that he bought carbon fibre from Boeing that was past its shelf life for use in airplanes ...