Glauco-class submarine

The "Glauco" class was a pair of submarines ordered by the Portuguese government, but were taken over and completed for the (Royal Italian Navy) during the 1930s. They played a minor role in the Spanish Civil War of 1936–1939 supporting the Spanish Nationalists.
Design and description.
The "Glauco"-class submarines were improved versions of the preceding . They displaced surfaced and submerged. The submarines were long, had a beam of and a draft of .
For surface running, the boats were powered by two diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a electric motor. They could reach on the surface and underwater. On the surface, the "Glauco" class had a range of at ; submerged, they had a range of at .
The boats were armed with eight internal torpedo tubes, four each in the bow and stern. They carried a total of 14 torpedoes. They were also armed with two deck guns, one each fore and aft of the conning tower, for combat on the surface. Their anti-aircraft armament consisted of one or two machine guns.
Service.
Both boats were built by CRDA in its Trieste shipyard. The submarines had initially been ordered in 1931, but were acquired by the Italians when Portugal cancelled the order. Both boats were launched in 1935, and they saw action in the Spanish Civil War and the Second World War. "Glauco" was badly damaged by the British destroyer HMS "Wishart"" "and scuttled by her own crew on 27 June 1941, west of Gibraltar; "Otaria" was surrendered to the Allies in 1943 and used for training until it was sent to the junkyard in 1948.