The Casabianca (ex-Bourgogne) is a first-generation nuclear attack submarine of the French Navy. She is named in honour of the famous submarine of the Free French Naval Forces Casabianca. She is the third of the Rubis series. Between 1993 and June 1994, she undertook a major refitting which upgraded her to the level of the Améthyste, arming her for anti-submarine as well as anti-surface ship warfare. Her underwater endurance is 60 days, dictated by food supplies. She is designed to operate at seas 220 days per year, and is thus staffed by two crews that relay each other from one patrol or exercise to the next.