From economics to submersibles
Originally an economics student and teacher, Piccard joined his father Auguste’s submersible project in 1948. Father and son dived in Trieste in 1953. After the U.S. Navy bought the craft in 1958, Jacques served as a consultant, teaching its new operators how to use and maintain it.
The Challenger Deep descent
On 23 January 1960 Piccard and U.S. Navy officer Don Walsh descended to Challenger Deep in the Mariana Trench, roughly eleven kilometres below the surface. A pressure sphere protected the occupants, a light-liquid float supplied buoyancy, and releasable ballast controlled ascent and descent. The expedition also depended on surface and maintenance support.
References: [3]
Drift missions and lake observation
Piccard subsequently developed medium-depth submersibles. Auguste Piccard carried members of the public in Lake Geneva in 1964. In 1969 he led the Ben Franklin team on a month-long submerged drift in the Gulf Stream. His later F.-A. Forel submersible supported lake and coastal investigations.