Submersible Vehicles Carry Researchers to the Depths

But satellites and drilling rigs don't normally come to people's minds when they think of deep-sea exploration. For most people, undersea research means going down to the ocean bottom in a manned submersible (undersea exploration vessel). And many oceanographers agree that observations made from the surface can go only so far. A manned submersible enables them to get close to whatever they want to observe and see it with their own eyes. It also permits them to collect exactly the samples they want to study.

A submersible named the Trieste I holds the deep-diving record: a descent to a depth of 10,912 meters (35,800.5 feet) in the Challenger Deep of the Mariana Trench. The Trieste was not a true submarine, however, but a bathyscaph (from the Greek words for deep and tub). Like a hot-air balloon, it was designed to travel up and down. Not coincidentally, it was designed by Auguste Piccard (oh GOOST pee KAHR), a famous Swiss designer of high-altitude balloons. The vehicle's cigar-shaped outer hull contained several large compartments filled with gasoline, which is lighter than water. For ballast, it carried some 8 metric tons (9 tons) of iron shot, attached to the hull by powerful electromagnets. To make the Trieste sink, the pilot released enough gasoline to lose buoyancy. To make it rise, he turned off one or more of the magnets long enough to drop the needed amount of ballast. The pilot and copilot sat in a pressurized steel sphere beneath the hull.

The Trieste made a series of successful dives beginning in 1953. On Jan. 23, 1960, it carried two men–Jacques Piccard, son of the inventor, and Lieutenant Don Walsh of the U.S. Navy—on the first-ever descent into the Challenger Deep. At the bottom of the trench, the men saw what appeared to be a bright-red shrimp and something they believed to be a type of flatfish. Most scientists, skeptical that fish could live at such a depth, insisted that the explorers had actually seen a strange type of creature known as a sea cucumber. Little information was gathered by the Trieste's dive—all Piccard and Walsh could do was sit in one place and observe—but it demonstrated that descending to the deepest parts of the ocean was possible.