Attention SCUBA divers! Crush depth of scuba tanks? NOT burst strength of tanks from internal pressure, but?

Question

how much external pressure can tanks withstand before rupture?

(please read rest of details! )

I KNOW it will be far deeper than a person could actually dive with scuba tanks. I am not looking for the maximum depth a person could reach.

Go to the deepest part of the ocean, put weights on the tanks so they will sink instead of floating, and let them go. How deep do they reach before the water pressure crushes the tanks and releases the air?

Also, will the answer vary depending on whether the tanks are full or empty? Does the internal pressure of the tank help to resist the external pressure of the water?

Finally, can analogous values be found for propane tanks, CO2 tanks, etc?

Which ones would provide the greatest buoyancy?

I may not be expressing this properly. Please be patient with me. If you don't understand, ask for more details and I WILL provide them. Thanks to all who give serious replies!

Thanks Robert, rest assured, this is not for actual use, theoretical only.

I have to get the details correct or my editors will reject my work (again!)

Do the manufacturers have a website where I could contact them?

Answer 1

Scuba air tanks are designed for over 3,000 lbs per sq.
inch internal pressure and are well made I would imagine
that they would also withstand external pressures in
multi thousands of feet also pro bally if they were full they could
withstand more.. do not use a propane tank as a air tank
they are not designed for pressures over 200 lbs and what
are you going to use for a regulator ?
Be extremely careful you are threading on dangerous waters here..
U.S. Divers is one
also my gages are Oceanic Instruments.
my regulater is a Mares..
Hope that helps.