Settembrini-class submarine

The Settembrini class was a pair of submarines built for the Regia Marina (Royal Italian Navy) during the late 1920s. They played a minor role in the Spanish Civil War of 1936–1939 supporting the Spanish Nationalists.

Design and description
The Settembrini class was an improved and enlarged version of the preceding Mameli-class submarines. They displaced 938 LT surfaced and 1135 LT submerged. The submarines were 69.11 m long, had a beam of 6.61 m and a draft of 4.45 m. They had an operational diving depth of 80 m. Their crew numbered 56 officers and enlisted men.

For surface running, the boats were powered by two 1500 bhp diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a 700 hp electric motor. They could reach 17.5 kn on the surface and 7.7 kn underwater. On the surface, the Settembrini class had a range of 6200 nmi at 7.3 kn; submerged, they had a range of 100 nmi at 3 kn.

The boats were armed with eight 53.3 cm torpedo tubes, four each in the bow and stern for which they carried a total of 12 torpedoes. They were also armed with a single 102 mm deck gun forward of the conning tower for combat on the surface. Their anti-aircraft armament consisted of two or four 13.2 mm machine guns.

Service history
During the Spanish Civil War, Luigi Settembrini made one patrol in the Eastern Mediterranean in September 1937 during which she sank a Soviet cargo ship.