Japanese titanium alloy deep sea diving survey ship

The Japanese manned deep-sea survey ship "deep-sea 6500" can dive 6500 meters into the ocean to investigate earthquake occurrence, seabed topography, geology and deep-sea organisms. At a depth of 6500 meters, objects per square centimeter bear 680 kilograms of water pressure. The cockpit of the ship is set in a spherical pressure shell made of lightweight and strong titanium alloy to ensure that the passengers will not be hurt by water pressure. The hull is made of buoyant materials to keep the submersible floating. During deep diving, the ballast tank puts in and releases seawater to adjust buoyancy.