DURING THE 1940s, Cousteau was credited with launching the aqualung, which gave birth to modern scuba diving. In 1942, after trials with unsatisfactory underwater rebreathing apparatuses, Cousteau added a demand regulator, which extended the time spent underwater. The tests were conducted during exploration of wrecks, often with Dumas diving and Cousteau behind a camera. The following year, Cousteau tried out the prototype aqualung — and the rest is diving history. Underwater exploration became possible.
Like many inventions, it seems simple in retrospect. Cousteau and his engineer had essentially redesigned a car fuel-pressure regulator and invented a demand regulator that would automatically deliver fresh air when a diver breathed. This underwater breathing apparatus was patented in 1945 as CG45: “C” for Cousteau, “G” for Gagnan the engineer, and “45” for 1945. With an eye to international markets, Cousteau swiftly gave it the English name “aqualung.” The device was compact, portable and mountable on air tanks to allow for deeper dives of over an hour, with compression stops, compared with the shorter, shallower dives of its predecessor (only 30 minutes at depths under 30 feet). Divers could finally explore the depths and monitor marine life as if they, too, were born for the sea.