The birth of the world's first deep-sea submersible

Bathysphere, a submersible launched nearly 100 years ago, helps realize scientists' desire to directly observe deep-sea creatures .

In 1925, American naturalist William Beebe proposed the idea of ​​a diving vehicle that could take people into the deep sea. As of the late 1920s, the greatest depth to which humans could safely dive with a diving helmet was only a few hundred feet (1 ft equals about 0.3 m). Submarines at that time reached a maximum depth of 117m, but had no windows, so they were useless for Beebe's goal of observing deep-sea animals. The greatest depth that humans had ever gone down to at that time was 160 m with armor, but these suits also made movement and observation very difficult.

William Beebe (left) and Otis Barton (right) with the Bathysphere submersible. (Photo: Rare Historical Photos).

Beebe hoped to create a ship that could both dive much deeper than the record at the time, and also allow him to clearly observe and record wildlife in the deep ocean. Eventually, Beebe teamed up with engineer Otis Barton , who had ambitions of becoming a deep-sea explorer. Barton designed the ship to be spherical, because the spherical shape helps withstand enormous pressure.

The sphere had holes for three 76mm thick windows made from fused quartz, the strongest transparent material of its time. A door weighing 180kg will be closed before the ship submerges. Oxygen is supplied from high-pressure tanks placed inside the sphere, while devices containing soda lime and calcium chloride are mounted on the inside of the ship's walls to absorb moisture and released CO _{2 .} There was a lamp mounted right in one of the windows to illuminate the creatures outside. The ship is also equipped with a telephone system to help people inside contact above.

Beebe named the ship Bathysphere after the genus Bathytroctes , a group of deep-sea fish. To operate, the ship is lowered into the water using cables.

After the first version of the sphere was cast in June 1929, experts found it was too heavy to be lifted and lowered into the sea by a winch. This caused Barton to melt the sphere and recast it.

The final design became lighter, being a hollow sphere of 25mm thick cast steel with a diameter of 1.45m. When on land, its weight is 2.25 tons. The steel cable is 910m long and weighs 1.35 tons. The ship is also equipped with cameras, thermometers and depth gauges.

On June 11, 1930, Bathysphere descended to a depth of 400m, then reached 900m in 1934. Through these dives, the ship demonstrated its capabilities but also revealed its weaknesses. It is very difficult to operate and poses great risks. Breaking the connecting cable can bring death to observers.

Simulate the Bathysphere submersible operating in the deep sea. (Photo: Else Bostelmann).

Beebe continued to conduct research during the 1930s. But by then, he felt he had made enough observations with the Bathysphere, and that continuing to dive would be too costly for the knowledge he had gained. When World War II broke out, Bermuda was converted into a military base, significantly destroying the natural environment and making it impractical to study it more closely.

After Beebe discontinued use of the Bathysphere, it remained the property of the New York Zoological Society. The ship was stored until it was displayed at the New York World's Fair in 1939. In 1957, the ship was displayed at the New York Aquarium.

Although the Bathysphere's technology gradually became obsolete and was replaced by more advanced submersibles, the ship made it possible for researchers to observe deep-sea animals in their natural environment for the first time, making money set an example for many other researchers to follow in the future. Therefore, Bathysphere's contributions to oceanography and deep-sea exploration are still remarkable.