Leon Battista Alberti's attempt
Devices for swimming, diving, and recovering objects underwater appear in many technical manuscripts of the Renaissance, which illustrated their military as well as civilian applications.
Such mechanisms were used by Leon Battista Alberti in his failed attempt of approximately 1446 to salvage the wreck of one of the two Roman ships resting on the bed of Lake Nemi.
The project?depicted in an illustration attributable to Francesco di Giorgio's circle?aroused tremendous interest. Indeed, it may have inspired some of the underwater devices and buoyancy-based apparatus shown in Renaissance manuscripts.
Salvaging the ships
After the attempts by Francesco De Marchi?who explored them with a diving bell in 1535?and other later tries, the two Nemi boats were salvaged by Guido Ucelli between 1929 and 1931 by means of a partial drainage of the lake. However, the vessels were destroyed in a fire during World War II.
The ships were 201 and 213 feet long respectively. Built in the reign of Caligula, they provided superb evidence of Roman artistic and technological achievement.