Developed in France by IFREMER and COMEX, SAGA is the first prototype of a new generation of industrial submarines capable of carrying out underwater operations using divers or robots at close proximity to the work site without surface assistance. SAGA (28 meters long, 550 tons submerged displacement, 6 crew members) has a hyperbaric compartment for 4 to 6 divers. Several important innovations, in particular with regards to energy, give SAGA an exceptional autonomy, essential for performing deep underwater operations. The submarine was launched in October 1987 and has just completed to three-year qualification programme. Since May 1990 SAGA holds the world record of the deepest (-317 m) diver lock-out operation from a submarine. This paper presents the new technologies used for the construction of SAGA and draws up a first appraisal of this ambitious project.