SEMT Pielstick
Designated "hunter submarines" () by the French Navy the "Aréthuse" class were designed as attack submarines specifically for operations in the Mediterranean Sea. The design retained a small silhouette and great manoeverability. They had a standard displacement of , surfaced and submerged. "Argonaute" is long with a beam of and a draught of . The "Aréthuse" class were the first French submarines to use a diesel-electric propulsion system and were powered by two 12-cylinder SEMT Pielstick diesel engines driving one shaft rated at surfaced. They also mounted two electric generators that produced connected to one electric motor for use while submerged rated at . The generators were placed on spring suspensions and the motor was attached directly to the shaft creating a near-silent operational environment while submerged. "Argonaute" had a maximum speed of surfaced and submerged.