SM U-11 (Austria-Hungary)

SM U-11 or U-XI was a U-10-class submarine in the Austro-Hungarian Navy (German: Kaiserliche und Königliche Kriegsmarine or K.u.K. Kriegsmarine) during World War I. She was originally a German Type UB I submarine commissioned into the German Imperial Navy (German: Kaiserliche Marine) as SM UB-15.

SM U-11
SM U-11
German Empire
Name: UB-15
Ordered: 15 October 1914
Builder: AG Weser, Bremen[1]
Yard number: 224
Laid down: 9 November 1914[2]
Commissioned: 11 April 1915[2]
Fate: Transferred to Austria-Hungary, 14 June 1915[1][Note 1]
Service record as UB-15
Commanders: Heino von Heimburg (4–17 June 1915)[2]
Victories: 1 warship (245 GRT) sunk[2]
Name: SM U-11
Acquired: 14 June 1915[1]
Commissioned: 18 June 1915[3]
Fate: War reparation to Italy; scrapped at Pola, 1920[1]
Service record as U-11[4]
  • Lüdwig Eberhardt (June–August 1915)
  • Karl Edler von Unczowski (September–October 1915)
  • Robert Teufl von Fernland (October 1915–August 1916)
  • Johann Krsnjavi (August 1916–May 1917)
  • Ludwig Müller (May–July 1917)
  • Wladimir Pfeifer (July–September 1917)
  • Eugen Hornyák Edler von Horn (September 1917–January 1918)
  • Hugo Pistel (January–June 1918)
  • Alfons Graf Montecuccoli (June–August 1918)
  • Alois Sernetz (August–October 1918)
Victories: None
General characteristics [5]
Class and type: German Type UB I submarine
Type: U-10-class submarine
  • 127 tonnes (125 long tons) surfaced
  • 141 tonnes (139 long tons) submerged
Beam: 3.15 m (10 ft 4 in)
Draught: 3.03 m (9 ft 11 in)
  • 6.5 knots (12.0 km/h; 7.5 mph) surfaced
  • 5.5 knots (10.2 km/h; 6.3 mph) submerged
  • 1,500 nmi (2,800 km; 1,700 mi) at 5 knots (9.3 km/h; 5.8 mph) surfaced
  • 45 nmi (83 km; 52 mi) at 4 knots (7.4 km/h; 4.6 mph) submerged
Complement: 17

SM UB-15 was constructed in Germany and shipped by rail to Pola, where she was assembled and launched. She was commissioned into the German Imperial Navy in April and sank an Italian submarine in June. The boat was handed over to Austria-Hungary and commissioned as SM U-11 on 14 June. In early 1916, U-11 fired on a British submarine, but missed. After the end of the war, U-11 was handed over to Italy as a war reparation and scrapped at Pola by 1920.

Design and constructionEdit

U-11 was a small coastal submarine that displaced 127 tonnes (125 long tons) surfaced and 141 tonnes (139 long tons) submerged. She featured a single shaft, a single 60 bhp (45 kW) Körting diesel engine for surface running, and a single 120 shp (89 kW) electric motor for submerged travel.[1] U-11 was capable of up to 6.5 knots (12.0 km/h; 7.5 mph) while surfaced and 5.5 knots (10.2 km/h; 6.3 mph) while submerged at a diving depth of up to 50 metres (160 ft). She was designed for a crew of 17 officers and men.[1]

U-11 was equipped with two 45 cm (17.7 in) torpedo tubes located in the front and carried a complement of two torpedoes.[1] German Type UB I submarines were additionally equipped with a 8 mm (0.31 in) machine gun, but it is not clear from sources if U-11 – a former German boat – was fitted with one, or if it was, retained it in Austro-Hungarian service. In October 1916, U-11's armament was supplemented with a 66 mm (2.6 in)/18 (2.6 in) gun.[1]

UB-15 was laid down on 9 November 1914 at AG Weser in Bremen. The submarine was shipped by rail in sections to Pola Navy Yard, where the sections were riveted together. There is no known surviving record of how long it took for UB-15's sections to be assembled. However, a similar ship (UB-3) was built in two weeks.[6]

Operational historyEdit


SM UB-15 was commissioned into the German Imperial Navy under the command of Oberleutnant zur See Heino von Heimburg on 11 April.[2] An Austro-Hungarian Navy officer was assigned to the boat for piloting and training purposes. On 10 June, UB-15 sank the Italian submarine Medusa for a loss of 245 tons off Porto di Piave Vecchia in the Northern Adriatic.[7][8][Note 2] Like all Type UB I and U-10 class submarines, UB-15 was equipped with compensating tanks designed to flood and offset the loss of one of the 1,700-pound (770 kg) C/06 torpedoes.[9] However, they did not always function correctly; when firing from periscope depth the boat could broach after firing or, if too much weight was taken on, plunge to the depths. When UB-15 torpedoed and sank Medusa, the tank failed to properly compensate, forcing all of the crewmen to run to the stern to offset the trim imbalance and prevent the ship from sinking.[9]


On 18 June, UB-15 was handed over to the Austro-Hungarian Navy and commissioned as U-11 under the command of Linienschiffsleutnant Lüdwig Eberhardt.[3] U-11 retained its German crew until 18 June 1916, when they were replaced by an all Austro-Hungarian one.[10] In early 1916, U-11 unsuccessfully attacked the British submarine B8 in the Gulf of Fiume.[11] U-11 sank no ships in her Austro-Hungarian service,[4] and was handed over to Italy as a war reparation and scrapped at Pola by 1920.[1]

Summary of raiding historyEdit

Date Name Nationality Tonnage
10 June 1915 Medusa   Regia Marina 245 Sunk


  1. ^ Sources differ as to exactly when the U-boat was transferred over to the Austro-Hungarian navy. See Stern, p. 193.
  2. ^ Sources differ as to whether the U-boat was under German or Austro-Hungarian ownership when she sank the Medusa. See Stern, p. 193.


  1. ^ a b c d e f g h i j Gardiner, p. 343.
  2. ^ a b c d e Helgason, Guðmundur. "WWI U-boats: UB 15". German and Austrian U-boats of World War I - Kaiserliche Marine - Retrieved 4 November 2008.
  3. ^ a b Freivogel 2007, p. 10.
  4. ^ a b Helgason, Guðmundur. "WWI U-boats: KUK U11". German and Austrian U-boats of World War I - Kaiserliche Marine - Retrieved 4 November 2008.
  5. ^ Gröner 1991, p. 49.
  6. ^ Messimer, p. 126–27.
  7. ^ Helgason, Guðmundur. "Ships hit during WWI: Medusa". German and Austrian U-boats of World War I - Kaiserliche Marine - Retrieved 4 November 2008.
  8. ^ Compton-Hall, p. 235.
  9. ^ a b Stern, p. 25.
  10. ^ Erwin Sieche. "The Austro-Hungarian Submarine Force". "Austro-Hungarian Warships In Photographs, Vol. 2. 1896-1918". Retrieved 8 February 2010.
  11. ^ Compton-Hall, p. 240.
  12. ^ Helgason, Guðmundur. "Ships hit by UB 15". German and Austrian U-boats of World War I - Kaiserliche Marine - Retrieved 26 January 2015.