Nazario Sauro-class

The Sauro class is a series of diesel-electric submarines developed for the Italian Navy during the 1970s. Designed to counter Soviet underwater forces, the vessels were constructed by Italcantieri (later Fincantieri) at the Monfalcone shipyard. The class succeeded the Toti, Tang, and Tench classes and was followed by the Todaro class.

Eight submarines were produced in four distinct batches. Batch I, consisting of the Nazario Sauro and Carlo Fecia di Cossato, entered service between 1979 and 1980. Batch II, including the Leonardo da Vinci and Guglielmo Marconi, followed in 1982. The Italian Navy later ordered two additional pairs: Batch III (Salvatore Pelosi and Giuliano Prini) and Batch IV (Primo Longobardo and Gianfranco Gazzana Priaroggia), which were delivered between 1988 and 1995.

The propulsion system features Grandi Motori Trieste diesel engines and an electric motor. Batches I through III were equipped with Magneti Marelli electric engines, while Batch IV integrated an ABB motor. Sensor and processing suites transitioned from SMA radar and Elsag-USEA sonar in earlier batches to STN Atlas Elektronik sonar and combat systems in later units. Periscopes were initially supplied by Barr & Stroud, with later vessels using Kollmorgen optics. The armament configuration across all batches consists of bow torpedo tubes for the deployment of Whitehead A-184 series torpedoes or naval mines.

Operational history includes the retirement of the first two batches between 2001 and 2010. The Nazario Sauro (S 518) was decommissioned in 2002 and subsequently preserved as a museum ship in Genoa. Four vessels from Batches III and IV remain in active service. These units underwent modernizations between 1999 and 2005, which included updates to acoustic sensors, weapons control systems, and communication suites. A proposal for the United States to acquire retired units for refurbishment and resale to Taiwan was discussed but not implemented.