Pier Capponi was one of four Mameli-class submarines built for the Regia Marina (Royal Italian Navy) during the 1920s.

[1] For surface running, the boats were powered by two 1,550-brake-horsepower (1,156 kW) diesel engines, each driving one propeller shaft.

On the surface, the Mameli class had a range of 4,360 nautical miles (8,070 km; 5,020 mi) at 8 knots (15 km/h; 9.2 mph); submerged, they had a range of 110 nmi (200 km; 130 mi) at 3 knots (5.6 km/h; 3.5 mph).

They were also armed with a single 102-millimeter (4 in) deck gun forward of the conning tower for combat on the surface.

[3] During World War II, the Royal Navy submarine HMS Rorqual torpedoed and sank her in the Tyrrhenian Sea south of Stromboli at 38°32′N 015°19′E / 38.533°N 15.317°E / 38.533; 15.317 (Pier Capponi) on 31 March 1941.