The spherical bathyscaphe Trieste that took 2 people to the bottom of Challenger Deep was 7 feet in diameter.
If the vessel had a yield strength in compression in equal to that of 4340-HR steel (901 x 10^6Pa) and a safety factor of 2 was employed, what would the wall thickness need to be to withstand the pressure at the bottom of Challenger Deep (1086 atm) ?