Brin-class submarine

The Brin-class submarine was a group of five long-range submarines built for the Royal Italian Navy (Regia Marina) during the 1930s.

Design and description
The Brin-class submarines were improved versions of the preceding Archimede-class submarine. Two boats were replacements for submarines of that class that were secretly transferred to the Nationalists during the Spanish Civil War in 1937. They displaced 1000 t surfaced and 1254 t submerged. The submarines were 72.47 m long, had a beam of 6.68 m and a draft of 4.54 m. The class was partially double hulled.

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 550 hp electric motor. They could reach 17.3 kn on the surface and 7.8 kn underwater. On the surface, the Brin class had a range of 9000 nmi at 8 kn, submerged, they had a range of 90 nmi at 4 kn.

The boats were armed with eight internal 53.3 cm torpedo tubes, four each in the bow and stern. They carried a total of 14 torpedoes. They were also armed with one 100 mm deck gun for combat on the surface. The gun was initially mounted in the rear of the conning tower, but this was re-sited on the forward deck later in the war in the surviving boats and the large conning tower was re-built to a smaller design. The light anti-aircraft armament consisted of one or two pairs of 13.2 mm machine guns.