Ostro was one of eight s built for the (Royal Italian Navy) during the 1920s. She was named after a southerly wind, Ostro, common in the Mediterranean and Adriatic. The ship played a minor role in the Spanish Civil War of 1936âÂÂ1937, supporting the Nationalists.
The Turbine-class destroyers were enlarged and improved versions of the preceding . They had an overall length of , a beam of and a mean draft of . They displaced at standard load, and at deep load. Their complement was 12 officers and 167 enlisted men.
The Turbines were powered by two Parsons geared steam turbines, each driving one propeller shaft using steam supplied by three Thornycroft boilers. The turbines were rated at for a speed of in service, although her sister ships reached speeds in excess of during their sea trials while lightly loaded. They carried enough fuel oil to give them a range of at a speed of .
Their main battery consisted of four guns in two twin-gun turrets, one each fore and aft of the superstructure. Anti-aircraft (AA) defense for the Turbine-class ships was provided by a pair of AA guns in single mounts amidships and a twin-gun mount for machine guns. They were equipped with six torpedo tubes in two triple mounts amidships. The Turbines could carry 52 mines.
Ostro was laid down by Gio. Ansaldo & C. at their Genoa shipyard on 29 April 1925, launched on 2 January 1928 and completed on 9 October. Upon her completion, Ostro, together with other vessels of her class conducted exercises in the Tyrrhenian Sea and visited Monaco to attend the celebrations of the local Italian community. Together with , and the ship was assigned to the 1st Squadron of the I Destroyer Flotilla based at La Spezia. In 1929 she carried out a training cruise of the coast of Spain, and in 1930 another one in the Dodecanese and Aegean Sea. In 1931 Ostro together with , and as well as older , and formed 1st Destroyer Flotilla, part of II Naval Division. In 1934 after another reorganization Ostro as well as , and were again reunited, now forming the 4th Destroyer Squadron, part of II Naval Division.
After the Civil War started in Spain in July 1936, both Italy and Nazi Germany supported the Nationalists of General Franco, whereas Soviet Union was actively supporting the Republicans. During the first year of the war, the Soviets used the Republican controlled ports of Bilbao and Santander in the North of Spain adjacent to the French border, but after their fall in the summer of 1937, the USSR was forced to use ports in the Mediterranean to continue supplying the Republicans. Both Italy and Germany deployed their submarines in the Mediterranean in early 1937 to interdict with Republican shipping, but without much success. On 3 August 1937 Franco made an urgent plea with Mussolini to use the Italian fleet to prevent the passage of a large Soviet transport convoy, which just departed from Odessa. Originally, only submarines were supposed to be used, but Mussolini was convinced by Franco to use Italian surface ships too against the Soviets. The Italian blockade was put into effect immediately, with two cruisers, and , eight torpedo boats and eight destroyers, including Ostro being deployed in and around the Strait of Sicily and Strait of Messina.
In the evening of 13 August 1937 Ostro, under command of captain Teodorico Capone, while patrolling off Bizerte, just north of the island of Linosa, spotted and attacked Spanish Republican steamer sailing from Cartagena to Odessa in ballast. At 20:43 the Spanish ship was struck by a torpedo and sank in the position , off Pantelleria. Twenty-three members of the ship's crew were picked up by the British steamer , and landed in Algiers on 17 August.
On 30 August 1937 , under command of captain Virgilio Rusca, was on patrol together with Ostro, when they encountered Soviet steamer around 16:00. The destroyers continued shadowing the ship until the darkness fell, and around 21:00 launched two torpedoes at the Soviet vessel, and Ostro launched one. The cargo ship was hit by two torpedoes in quick succession and rapidly sank in the position