Spica-class torpedo boat

The Spica class was a class of torpedo boats of the Regia Marina (Royal Italian Navy) during World War II. These ships were built as a result of a clause in the Washington Naval Treaty, which stated that ships with a tonnage of less than 600 could be built in unlimited numbers. Thirty-two ships were built between 1934 and 1937, thirty of which entered service with Italy and two of which were sold to the Swedish Navy in 1940. The two units in Swedish service were classified as destroyers until 1953, then re-classified as corvettes. Although commonly referred to as torpedo boats due to their smaller displacement, the Spica class armament was similar to destroyers (their design was influenced by the Maestrale-class destroyer then in development) and were intended for anti-submarine operations but had to fight aircraft and surface forces. Twenty-three vessels were lost during the war.

Design
The design work started in 1932, and two prototypes, Spica and Astore, were built. The hull was 80 m long, and displacement was around 720 ST standard rather than the 600 ST permitted by the Washington treaty. Propulsion consisted of a two-shaft, geared turbine layout with two Yarrow–type boilers.

The gun armament consisted of three 100 mm/47 caliber dual-purpose guns in single mountings in 'A', 'X', and 'Y' positions and three or four twin 13.2 mm anti-aircraft machine guns, later replaced by 6 to 11 Breda 20/65 modello 35 20 mm cannons in various configurations. (Lupo, for example, replaced her eight machine-guns by 1941 with three twin 20 mm guns; two abreast the bridge and one between the funnel and second main gun, leaving the former MG platform immediately abaft the funnel vacant.)

They also carried four 450 mm torpedo tubes; two single tubes for each side in the first group, with later groups having varying configurations including a centreline twin and two single beam mounts, before settling on two centreline twin mounts in the last vessels. Some earlier ships were reportedly refitted with the all-centreline arrangement during the war. This weapon had a shorter range and a smaller warhead than the 533 mm torpedoes in use on destroyers.

Ships
Notes to table: