Sirena-class submarine

Class overview
Operators	Regis Marina
Preceded by	Argonauta class
Succeeded by	Perla class
Built	1931–1934
In commission	1933–1948
Completed	12
Lost	11
Scrapped	1
General characteristics
Type	Submarine
Displacement	691 t (680 long tons) (surfaced) 850 t (837 long tons) (submerged)
Length	60.18 m (197 ft 5 in)
Beam	6.45 m (21 ft 2 in)
Draft	4.7 m (15 ft 5 in)
Installed power	1,350 bhp (1,010 kW) (diesels) 800 hp (600 kW) (electric motors)
Propulsion	2 shafts; diesel-electric 2 × diesel engines 2 × electric motors
Speed	14 knots (26 km/h; 16 mph) (surfaced) 7.5 knots (13.9 km/h; 8.6 mph) (submerged)
Range	5,000 nmi (9,300 km; 5,800 mi) at 8 knots (15 km/h; 9.2 mph) (surfaced) 72 nmi (133 km; 83 mi) at 4 knots (7.4 km/h; 4.6 mph) (submerged)
Armament	1 × single 100 mm (3.9 in) deck gun 2–4 × single 13.2 mm (0.52 in) machine guns 6 × 533 mm (21 in) torpedo tubes (4 bow, 2 stern)

The Sirena-class submarines were the second sub-class of the 600 Series of coastal submarines built for the Regia Marina (Royal Italian Navy) during the early 1930s. Of the dozen boats built of this class, only one survived World War II.