5800 PSI....and here's the thing. At the depth of the Titanic, it's ONLY TWO HUNDRED METERS away from the submersible's maximum depth. Talk about stupid. Since it has previous dives, each time stresses the hull. It does have a life span. There wasn't enough of a cushion if you ask me. The DeepSea Challenger could do it. It's withstood over EIGHT TONS PSI a few times to the bottom of the Mariana's Trench. That's almost 36,000 feet.
Supposedly the view port on the sub was only rated to 1400meters cause they didn't want to spend money on better.. and the owner of that company many times has complained that safety is over-rated and a pain and not worth doing....