The Italian built, but US Navy operated TRIESTE is famous for having
taken two men (Dr Jacques Piccard and Lt Donald Walsh) to the bottom of the deepest
part of the ocean floor The Challenger Deep near the Philippines, in
the Pacific Ocean. Trieste took nearly five hours to sink the 11 Kilometers to reach
the ocean floor.
Built in the early 50's, Trieste dives by filling its body with water and by carrying over 9 tons of steel shot as ballast. Inside the balloon-like body is a resevoir of gaseoline - the incoming water compresses the gaseoline - enabling the hull to withstand the incredible pressure of the sea at depths of several miles below the ocean surface
To rise back to the surface, the Trieste jettisoned the steel shot - the gaseoline making the vessel light enough to float back up to the surface.
The crew sat in the pressurised ball slung under the belly of the vessel.