Sirena-class submarine

The Sirena class was the second sub-class of the Italian 600 Series of coastal submarines, a dozen boats built for the Regia Marina between 1931 and 1934. It was an improved and enlarged version of the Argonauta class, about 61.5 metres long, with two diesel engines giving a surface speed of 14 knots and an armament of six 533 mm torpedo tubes and a 100 mm deck gun. Construction was shared among four yards: Odero Terni Orlando at Muggiano, Tosi at Taranto, the Cantieri Riuniti dell'Adriatico yard at Monfalcone, which built the lead boat Sirena and several of her sisters, and the Quarnaro yard at Fiume. Only one of the twelve survived the Second World War, and the design was the basis for the Yugoslav Sutjeska class.