T7 was a sea-going torpedo boat operated by the Royal Yugoslav Navy between 1921 and 1941, after spending World War I in Austro-Hungarian Navy service. Originally 96 F, she was a 250t-class torpedo boat, and saw active service during World War I, performing convoy, patrol, escort and minesweeping tasks, and anti-submarine operations. Following Austria-Hungary's defeat in 1918, 96 F was allocated to the Navy of the Kingdom of Serbs, Croats and Slovenes, which later became the Royal Yugoslav Navy, and was renamed T7. At the time, she and the seven other 250t-class boats were the only modern sea-going vessels of the fledgling maritime force.

T7
a black and white photograph of a small ship underway
T7's sister ship, T3. The only significant external difference was that T7 had two funnels.
History
Austria-Hungary
Name: 96 F
Builder: Ganz & Danubius
Laid down: 24 February 1915
Launched: 7 July 1916
Commissioned: 23 November 1916
Out of service: 1918
Fate: Assigned to the Kingdom of Serbs, Croats and Slovenes
Kingdom of Yugoslavia
Name: T7
Acquired: March 1921
Out of service: April 1941
Fate: Captured by Italy
Italy
Name: T7
Acquired: April 1941
Out of service: September 1943
Independent State of Croatia
Name: T7
Acquired: September 1943
Fate: Run aground by British MTBs on 24 June 1944 and then destroyed
General characteristics
Class and type: 250t-class, F-group sea-going torpedo boat
Displacement:
  • 266 t (262 long tons)
  • 330 t (325 long tons) (full load)
Length: 58.5 m (191 ft 11 in)
Beam: 5.8 m (19 ft 0 in)
Draught: 1.5 m (4 ft 11 in)
Installed power:
Propulsion:
Speed: 28 knots (52 km/h; 32 mph)
Range: 1,200 nmi (2,200 km; 1,400 mi) at 16 knots (30 km/h; 18 mph)
Complement: 38–41
Armament:

During the interwar period, T7 and the rest of the navy were involved in training exercises and cruises to friendly ports, but activity was limited by reduced naval budgets. The ship was captured by the Italians during the German-led Axis invasion of Yugoslavia in April 1941. After her main armament was modernised, she served with the Royal Italian Navy under her Yugoslav designation, conducting coastal and second-line escort duties in the Adriatic. Following the Italian capitulation in September 1943, she was handed over by the Germans to the Navy of the Independent State of Croatia. She was driven aground by British motor torpedo boats in June 1944 and destroyed by the British Army to prevent her salvage.

BackgroundEdit

In 1910, the Austria-Hungary Naval Technical Committee initiated the design and development of a 275-tonne (271-long-ton) coastal torpedo boat, specifying that it should be capable of sustaining 30 knots (56 km/h; 35 mph) for 10 hours. This specification was based an expectation that the Strait of Otranto, where the Adriatic Sea meets the Ionian Sea, would be blockaded by hostile forces during a future conflict. In such circumstances, there would be a need for a torpedo boat that could sail from the Austro-Hungarian Navy (German: kaiserliche und königliche Kriegsmarine) base at the Bocche di Cattaro (Bay of Kotor) to the Strait during the night, locate and attack blockading ships and return to port before morning. Steam turbine power was selected for propulsion, as diesels with the necessary power were not available, and the Austro-Hungarian Navy did not have the practical experience to run turbo-electric boats. Stabilimento Tecnico Triestino (STT) of Trieste was selected for the contract to build the first eight vessels, designated the T-group. Another tender was requested for four more boats, but when Ganz & Danubius reduced their price by ten percent, a total of sixteen boats were ordered from them, designated the F-group.[1] The F-group designation signified the location of Ganz & Danubius' main shipyard at Fiume.[2] 96 F was the fifteenth boat of the F-group to be completed.[3]

Description and constructionEdit

The 250t-class F-group boats had a waterline length of 58.5 metres (191 ft 11 in), a beam of 5.8 m (19 ft), and a normal draught of 1.5 m (4 ft 11 in). While their designed displacement was 266 tonnes (262 long tons), they displaced about 330 tonnes (325 long tons) fully loaded.[2] The crew consisted of 38–41 officers and enlisted men.[2][1] The boats were powered by two AEG-Curtiss steam turbines driving two propellers, using steam generated by two Yarrow water-tube boilers,[1] one of which burned fuel oil and the other coal. The turbines were rated at 5,000 shaft horsepower (3,700 kW) with a maximum output of 6,000 shp (4,500 kW), and were designed to propel the boats to a top speed of 28 knots (52 km/h; 32 mph).[2] They carried 20 tonnes (19.7 long tons) of coal and 34 tonnes (33.5 long tons) of fuel oil,[4] which gave them a range of 1,200 nautical miles (2,200 km; 1,400 mi) at 16 knots (30 km/h; 18 mph).[2] The F-group had two funnels rather than the single funnel of the T-group.[1] Due to inadequate funding, 96 F and the rest of the 250t class were essentially coastal vessels, despite the original intention that they would be used for "high seas" operations.[5] They were the first small Austro-Hungarian Navy boats to use turbines, and this contributed to ongoing problems with them.[1]

The boats were armed with two Škoda 66 mm (2.6 in) L/30[a] guns, and four 450 mm (17.7 in) torpedo tubes.[1] They could also carry 10–12 naval mines.[2] 96 F was the second-to-last of its group to be completed, and was laid down on 24 February 1915, launched on 7 July 1916 and completed on 23 November of that year.[3]

CareerEdit

World War I and the interwar periodEdit

During World War I, 96 F was used for convoy, patrol, escort and minesweeping tasks, and anti-submarine operations.[1] In 1917, one of the 66 mm (2.6 in) guns on each boat of the class was placed on an anti-aircraft mount.[2] On the night of 11 May 1917, the Huszár-class destroyer Csikós, accompanied by 96 F and two other 250t-class boats, were pursued in the northern Adriatic by an Italian force of five destroyers, but were able to retire to safety behind a minefield. On 3 June, the destroyers Wildfang and Csikós, along with 96 F and another 250t-class boat, had a brief encounter with three Italian MAS boats off the mouth of the Tagliamento river in the far north of the Adriatic.[7]

96 F survived the war intact.[1] In 1920, under the terms of the previous year's Treaty of Saint-Germain-en-Laye by which rump Austria officially ended World War I, she was allocated to the Kingdom of Serbs, Croats and Slovenes (KSCS, later Yugoslavia). Along with three other 250t-class F-group boats, 87 F, 93 F and 97 F, and four 250t-class T-group boats, she was transferred in March 1921 to the Navy of the KSCS, which later became the Royal Yugoslav Navy (Serbo-Croatian Latin: Kraljevska Jugoslovenska Ratna Mornarica, KJRM).[8] Renamed T7 in KJRM service,[2] she and the other seven 250t-class boats were, at the outset, the only modern sea-going vessels in the KJRM.[9] In 1925, exercises were conducted off the Dalmatian coast, involving the majority of the navy.[10] In May–June 1929, six of the eight 250t-class torpedo boats accompanied the light cruiser Dalmacija, the submarine tender Hvar and the submarines Hrabri and Nebojša, on a cruise to Malta, the Greek island of Corfu in the Ionian Sea, and Bizerte in the French protectorate of Tunisia. It is not clear if T7 was one of the torpedo boats involved. The ships and crews made a very good impression while visiting Malta.[11] In 1932, the British naval attaché reported that Yugoslav ships engaged in few exercises, manoeuvres or gunnery training due to reduced budgets.[12]

World War IIEdit

Map of the Independent State of Croatia showing the location of Murter Island

In April 1941, Yugoslavia entered World War II when it was invaded by the German-led Axis powers. At the time of the invasion, T7 was assigned as the flagship of the 3rd Torpedo Division located at Šibenik, which included her three F-group sisters.[13] On 8 April, the four boats of the 3rd Torpedo Division, along with other vessels, were tasked to support an attack on the Italian enclave of Zara (Zadar) on the Dalmatia coast. They were subjected to three Italian air attacks and, after the last one, sailed from the area of Zaton into Lake Prokljan, where they remained until 11 April.[14] On 12 April, the 3rd Torpedo Division arrived at Milna on the island of Brač, and refused to follow orders to sail to the Bay of Kotor.[15] All four F-group boats, including T7, were captured by the Italians.[16]

T7 was then operated by the Italians under her Yugoslav designation, conducting coastal and second-line escort duties in the Adriatic. Her guns were replaced by two 76 mm (3 in) L/40 anti-aircraft guns,[17] but no other significant alterations were made to her.[18] The Italians capitulated in September 1943, and once under German control, T7 was handed over to the Navy of the Independent State of Croatia, serving under her Yugoslav designation. Her crew came under the influence of the Yugoslav Partisans, and were preparing to mutiny when the Germans intervened.[1][19] On 24 June 1944, she and the German S-boats S 154 and S 157 of the 7th S-Boat Flotilla were sailing between Šibenik and Rijeka, protecting German sea supply routes along the Adriatic, when they were attacked by the Royal Navy Fairmile D motor torpedo boats MTB 659, MTB 662 and MTB 670 near the island of Kukuljari, south of Murter Island.[20] Considering T7 one of the few significant threats to British boats in the region, the British commander ordered MTB 670 to launch a torpedo attack. The two torpedoes missed, so the MTBs pursued and approached the ship from abaft the beam. T7 opened fire at 150 yards (140 m). The MTBs returned fire with their forward and port guns, and within 30 seconds they had disabled her weapons and set her ablaze. At a speed of about 12 knots (22 km/h; 14 mph), T7 suddenly veered starboard, narrowly avoiding a collision with MTB 662 (it is not known whether her steering was damaged or if her crew was attempting to perform a ram) before running aground on Murter Island.[21] The MTBs rescued 21 crew.[20] The British crews later examined the wreck, capturing five more sailors and leaving her flooded and burning. A British Army demolition team destroyed the hulk to ensure it could not be salvaged.[21]

See alsoEdit

NotesEdit

  1. ^ L/30 denotes the length of the gun. In this case, the L/30 gun is 30 calibre, meaning that the gun was 30 times as long as the diameter of its bore.[6]

FootnotesEdit

  1. ^ a b c d e f g h i Gardiner 1985, p. 339.
  2. ^ a b c d e f g h Greger 1976, p. 58.
  3. ^ a b Greger 1976, p. 60.
  4. ^ Jane's Information Group 1989, p. 313.
  5. ^ O'Hara, Worth & Dickson 2013, pp. 26–27.
  6. ^ Friedman 2011, p. 294.
  7. ^ Cernuschi & O'Hara 2016, p. 67.
  8. ^ Vego 1982, p. 345.
  9. ^ Chesneau 1980, p. 355.
  10. ^ Jarman 1997a, p. 733.
  11. ^ Jarman 1997b, p. 183.
  12. ^ Jarman 1997b, p. 451.
  13. ^ Niehorster 2016.
  14. ^ Terzić 1982, p. 333.
  15. ^ Terzić 1982, p. 404.
  16. ^ Greger 1976, pp. 58 & 60.
  17. ^ Brescia 2012, p. 151.
  18. ^ Chesneau 1980, p. 304.
  19. ^ Chesneau 1980, p. 357.
  20. ^ a b Paterson 2015, p. 223.
  21. ^ a b Reynolds 2009, Chapter 7.

ReferencesEdit

  • Brescia, Maurizio (2012). Mussolini's Navy. Barnsley, South Yorkshire: Seaforth Publishing. ISBN 978-1-59114-544-8.
  • Cernuschi, Enrico & O'Hara, Vincent P. (2016). "The Naval War in the Adriatic Part II: 1917–18". In Jordan, John (ed.). Warship 2016. London, England: Bloomsbury. pp. 62–75. ISBN 978-1-84486-438-6.
  • Chesneau, Roger, ed. (1980). Conway's All the World's Fighting Ships, 1922–1946. London, England: Conway Maritime Press. ISBN 978-0-85177-146-5.
  • Friedman, Norman (2011). Naval Weapons of World War One. Annapolis, Maryland: Naval Institute Press. ISBN 978-1-84832-100-7.
  • Gardiner, Robert, ed. (1985). Conway's All the World's Fighting Ships, 1906–1921. London, England: Conway Maritime Press. ISBN 978-0-85177-245-5.
  • Greger, René (1976). Austro-Hungarian Warships of World War I. London, England: Ian Allan. ISBN 978-0-7110-0623-2.
  • Jane's Information Group (1989) [1946/47]. Jane's Fighting Ships of World War II. London, England: Studio Editions. ISBN 978-1-85170-194-0.
  • Jarman, Robert L., ed. (1997a). Yugoslavia Political Diaries 1918–1965. 1. Slough, Berkshire: Archives Edition. ISBN 978-1-85207-950-5.
  • Jarman, Robert L., ed. (1997b). Yugoslavia Political Diaries 1918–1965. 2. Slough, Berkshire: Archives Edition. ISBN 978-1-85207-950-5.
  • Niehorster, Leo (2016). "Balkan Operations Order of Battle Royal Yugoslavian Navy 6th April 1941". World War II Armed Forces: Orders of Battle and Organizations. Leo Niehorster. Retrieved 29 November 2016.
  • O'Hara, Vincent; Worth, Richard; Dickson, W. (2013). To Crown the Waves: The Great Navies of the First World War. Annapolis, Maryland: Naval Institute Press. ISBN 978-1-61251-269-3.
  • Paterson, Lawrence (2015). Schnellboote: A Complete Operational History. Barnsley, South Yorkshire: Seaforth Publishing. ISBN 978-1-84832-083-3.
  • Reynolds, Leonard (2009). Dog Boats at War. Stroud, Gloucestershire: The History Press. ISBN 978-0-7524-5045-2.
  • Terzić, Velimir (1982). Slom Kraljevine Jugoslavije 1941: Uzroci i posledice poraza [The Collapse of the Kingdom of Yugoslavia in 1941: Causes and Consequences of Defeat] (in Serbo-Croatian). 2. Belgrade, Yugoslavia: Narodna knjiga. OCLC 10276738.
  • Vego, Milan (1982). "The Yugoslav Navy 1918–1941". Warship International. XIX (4): 342–361. ISSN 0043-0374.