Galeb-class minelayer

The Galeb class was built as wartime M 1-class minesweepers by three German shipbuilding yards during 1917–1919. Their German designations and builders were: M 97, M 100 and M 112 — Joh. C. Tecklenborg, Geestemünde; M 106 — Reiherstieg, Hamburg; M 121 and M144 — Neptun, Rostock.[2] The M 1 class comprised 137 ships built between 1914 and 1918, divided into three sub-classes, M1914, M1915 and M1916, each with progressive improvements. The six ships of the Galeb class were all of the M1916 sub-class.[3] The ship hulls were of transverse steel frame construction with a box keel.[4] They had a raised forecastle and a round tug stern, a single tall funnel and two masts. The fore-mast was encircled by the bridge, and the main-mast was located immediately forward of the aft gun mount.[3]

The ships had a waterline length of 56.1 m (184 ft 1 in),[5][6] an overall length of 59.58–59.63 m (195 ft 6 in – 195 ft 8 in),[5] a beam of 7.3 m (23 ft 11 in), and a normal draught of 2.15 m (7 ft 1 in). They had a designed displacement of 508 tonnes (500 long tons),[5][6] and 548–560 tonnes (539–551 long tons) at deep load.[5] The overall length and deep load displacement of the Yugoslav vessels varied slightly due to their construction by different shipyards.[3] They used steam generated by two coal-fired marine boilers to drive two three-cylinder vertical triple expansion engines driving two propeller shafts,[4][6] each with a single 1.97 m (6 ft 6 in) diameter propeller. A single rudder was located between the propellers.[7] The boilers were located in separate boiler rooms, and the engines were installed in a single engine room.[3] Their engines were rated at 1,840–1,850 indicated horsepower (1,370–1,380 kW) and were designed to propel the ship at a top speed of 16 knots (30 km/h; 18 mph). They carried 115 tonnes (113 long tons) of coal, which gave them a range of 2,000 nmi (3,700 km; 2,300 mi) at 14 knots (26 km/h; 16 mph).[5] The crew consisted of 40 officers and men.[8]

The ships of the class had good seakeeping characteristics, were responsive to ship controls, and had a good turning circle. With their minesweeping gear extended, they could maintain a maximum speed of 12.5–13 knots (23.2–24.1 km/h; 14.4–15.0 mph). They were equipped to two yawls as ship's boats.[8] They were armed with two 105 mm (4.1 in) SK L/45 naval guns, and carried 120 rounds for each gun. They could carry 30 naval mines.[8]

Some of the crew of Labud in February 1928

The six minesweepers were bought as unarmed "tugs" by the government of the Kingdom of Serbs, Croats and Slovenes (later Yugoslavia) on 20 July 1921, for 1,400,000 marks each. Their German designations were M97, M100, M106, M112, M121 and M144. Taken into service in the navy of the new kingdom, they were initially classified as mining tenders,[10] or mine carriers (Serbo-Croatian: minonosci).[9] They were renamed Orao (Eagle), Galeb (Seagull), Gavran (Raven), Jastreb (Hawk), Kobac (Sparrow Hawk), and Sokol (Falcon), respectively.[11][15] They were utilised as training ships for the fledgling navy, and engaged in show the flag cruises along the Adriatic coast and islands, introducing the navy to the populace. They also exercised alongside the eight 250t-class torpedo boats the navy had acquired from defeated Austria-Hungary after World War I, as a means of assessing training standards.[16] In 1923, Gavran was renamed Labud (Swan).[11][15] In 1932, the British naval attaché reported that Yugoslav ships were engaging in little gunnery training, and few exercises or manoeuvres, due to reduced budgets.[17] In August 1935, the seaplane carrier Zmaj accompanied by Galeb, Labud and Kobac visited the Greek island of Corfu.[18] By 1936, the class had been re-classified as minelayers.[19] In 1938–39 Jastreb was refitted for oil-firing only.[15][20]

After World War II broke out, the ships were brought to a heightened state of readiness, although Yugoslavia remained neutral. In the weeks prior to the April 1941 German-led Axis invasion of Yugoslavia, the ships of the class laid several protective minefields along the coast. It is likely that mines laid near the island of Zlarin off the port of Šibenik by Labud and Kobac resulted in the loss of the 1,726-gross register ton (GRT) passenger steamer Prestolonaslednik Petar and the 1,204 GRT passenger steamer Karađorđe on 2 April, when they were directed to make port at Šibenik instead of the Bay of Kotor.[16] During the invasion, which commenced on 6 April, the ships of the class were captured in port by the Italians.[15] Kobac's crew defected with their ship to the newly-created fascist puppet state the Independent State of Croatia (Serbo-Croatian: Nezavisna Država Hrvatska, NDH) at Šibenik on 10 April, but she was soon after seized by the Italian navy. The crews of Galeb and Labud also sailed to Šibenik in an attempt to join the NDH navy, but were intercepted and captured by the Italians on 17 and 21 April respectively.[21][22] Also on 17 April,[21] Sokol and Orao were captured at Split while undergoing repairs. During the chaos of the surrender, Orao was sabotaged by an explosive charge in a boiler.[23] Jastreb was captured at the Bay of Kotor.[16] They were soon put into commission in the Italian navy as follows:

Zirona was damaged and beached near Benghazi on 24–25 November 1941 after a British air raid, and was destroyed by the Italians on 28 November.[15][26] Selve was damaged by a Royal Air Force air raid at Benghazi on 6 November 1942, and burned out,[27] finally being broken up in 1948.[24] Eso was torpedoed by Royal Navy aircraft 7 km (4.3 mi) east of Djerba Island off the Tunisian coast on 19 January 1943,[15][28] while on escort duty with the Palestro-class torpedo boat San Martino and two other vessels.[29] Unie was destroyed by an explosion at Bizerta following an air raid by the United States Army Air Forces on 30 January 1943.[30] The last of the class to be sunk during the war was Zuri, which had been renamed Oriole in June 1942.[20] She was scuttled by her crew on 10 July 1943 at Augusta, Sicily, in the face of advancing British troops,[15] following damage sustained in an air attack south of Messina.[31] The surviving vessel, Vergada, was recovered and handed back to the Royal Yugoslav Navy-in-exile at Malta on 7 December 1943.[21] She remained in service through the rest of the war, and became part of the post-war Yugoslav Navy, serving as Pionir from August 1945, and as Zelengora from 1955. She was finally disposed of in 1962.[15][24]