[1][2][3] Another of his major achievements was the "torretta butoscopica", (direct translation: exploration turret), a one-man atmospheric pressure underwater observation chamber deployed by a lifting cable from a ship, provided with a telephone, and supplied with breathing air from the surface, which he designed, built and tested.

He worked on the case of the Spanish steamship Cruz, sunk on Scoglio del Catalano (Catalan Cliff) on the west coast of Sardinia.

[1] Gianni's most widely known achievement was probably the discovery of the wreck of the SS Egypt, sunk in the Atlantic Ocean off the coast of Brest in Brittany, France, at a depth of about 120m and carrying a precious cargo of gold bullion and silver.

[4][5][citation needed] The tragedy occurred at a time of great euphoria given the real possibility of recovering the valuable sunken treasure of the Egypt.

[6] The operation achieved a resounding success at the international level since it was the first step in the world of deep-water recovery, something considered impossible at the time, carried out by Italian divers and which became possible thanks to the organization left by Gianni and the use of his inventions, especially the "torretta butoscopica".

Congratulations were sent from all over the world, including from George V (King of the United Kingdom), Benito Mussolini,[citation needed] and then-communications minister Costanzo Ciano.