Yugoslav submarine Hrabri

Yugoslav naval policy in the interwar period lacked direction until the mid-1920s.[1] It was generally accepted by the Yugoslav government that the Adriatic coastline was effectively a sea frontier, which the naval arm was responsible for securing with the resources made available. In 1926, a modest ten-year construction program was initiated to build up a force of submarines, coastal torpedo boats, and torpedo and conventional bomber aircraft to perform this role. The Hrabri-class submarines were one of the first new acquisitions aimed at developing a naval force capable of meeting this challenge.[2]

Hrabri (Brave) was built for the Kingdom of Serbs, Croats and Slovenes (later Yugoslavia) by the Vickers-Armstrong Naval Yard, on the River Tyne, in the United Kingdom.[3] Her design was based on the British L-class submarine of World War I, and she was built using parts originally assembled for HMS L67, which was never completed.[4] Like her sister submarine Nebojsa, she had an overall length of 72.05 metres (236 ft 5 in), a beam of 7.32 m (24 ft), and a surfaced draught of 3.96 m (13 ft). Her surfaced displacement was 991 tonnes (975 long tons) or 1,183 tonnes (1,164 long tons) submerged, and her crew consisted of 45 officers and enlisted men.[3] She had an operational depth of 60 m (200 ft).[5]

For surface running, Hrabri-class boats were powered by two diesel engines which were rated at 2,400 brake horsepower (1,800 kW) that drove two propeller shafts. When submerged, the propellers were driven by two electric motors generating 1,600 shaft horsepower (1,200 kW). They could reach a top speed of 15.7 knots (29.1 km/h; 18.1 mph) on the surface and 10 knots (19 km/h; 12 mph) using their electric motors when submerged.[6] On the surface, the boats had a range of 3,800 nautical miles (7,000 km; 4,400 mi) at 10 knots (19 km/h; 12 mph).[7]

The boats were armed with six bow-mounted 533 mm (21 in) torpedo tubes, and carried twelve torpedoes.[6] They were also equipped with two 102 mm (4 in) deck guns (one forward and one aft of the conning tower), and one machine gun.[3]

Hrabri was launched in 1927, as the first submarine of the navy of the Kingdom of Serbs, Croats and Slovenes, which later became the Royal Yugoslav Navy.[3] Along with Nebojša, she left the Tyne in late January 1928.[8] In company with the Yugoslav submarine tender Hvar, the two submarines arrived in the Bay of Kotor on the southern Adriatic coast on 8 April 1928.[9] In May and June 1929, Hrabri, Nebojša, Hvar and six torpedo boats accompanied the light cruiser Dalmacija on a cruise to Valletta, Malta, the Greek island of Corfu in the Ionian Sea, and Bizerte in the French protectorate of Tunisia. According to the British naval attaché, the ships and crews made a very good impression while visiting Malta.[10]

In June and July 1930, Hrabri, Nebojša and the fleet auxiliary Sitnica again cruised the Mediterranean, visiting Alexandria in Egypt and Beirut in Lebanon.[11] In 1932, the British naval attaché reported that Yugoslav ships engaged in few exercises or manoeuvres due to reduced budgets.[12] In 1934, Hrabri again visited Valletta and also the Kelibia Roads off the coast of Tunisia.[13] In August 1935, Hrabri visited Malta; this time in company with the more modern French-designed submarine Osvetnik.[14] In August and September 1937, Hrabri, along with the other French-made submarine Smeli and the depot ship Zmaj, visited Greece, including the port of Piraeus, and the islands of Crete and Corfu.[15]

When the German-led Axis invasion of Yugoslavia began on 6 April 1941, she was located in the Bay of Kotor along with the three other submarines of the flotilla.[16] On 10 April, Hrabri and Osvetnik received orders for an operation against the Italian enclave of Zara on the Dalmatian coastline, but the mission did not proceed.[17] Later during the invasion she was captured by the Italian XVII Corps at the Bay of Kotor.[5][18] She was given the number N3 by the Italians but was not recommissioned, and was scrapped later that year due to her poor condition.[3][6]

• List of ships of the Royal Yugoslav Navy