SM U-4 (Austria-Hungary)

SM U-4

U-4 on a prewar postcard
History
Austria-Hungary
Name:	SM U-4
Ordered:	1906
Builder:	Friedrich Krupp Germaniawerft, Kiel
Yard number:	136
Laid down:	12 March 1907
Launched:	20 November 1908
Commissioned:	29 August 1909
Fate:	Ceded to France as war reparation and scrapped, 1920
Service record
Commanders:	Lothar Leschanowsky (August – September 1910, April – September 1911) Rudolf Singule (September 1912 – July 1913) Hermann Jüstel (July 1913 – April 1915) Edgar Wolf (April 1915) Rudolf Singule (April 1915 – November 1917) Franz Rzemenowsky von Trautenegg (from November 1917)
Victories:	12 ships (18,264 GRT) sunk 3 ships (13 GRT) taken as prize 1 warship (5,400 GRT) damaged
General characteristics
Class and type:	U-3-class submarine
Displacement:	240 t surfaced 300 t submerged
Length:	138 ft 9 in (42.29 m)
Beam:	14 ft (4.3 m)
Draft:	12 ft 6 in (3.81 m)
Propulsion:	2 × shafts 2 × kerosene 4-cylinder two-stroke engines, 600 bhp (450 kW) total 2 × electric motors, 320 shp (240 kW) total
Speed:	12 knots (22 km/h) surfaced 8.5 knots (15.7 km/h) submerged
Range:	1,200 nmi (2,200 km) at 12 knots (22 km/h), surfaced 40 nmi (74 km) at 3 knots (5.6 km/h), submerged
Complement:	21
Armament:	2 × 45 cm (17.7 in) torpedo tubes (both front) 3 torpedoes

SM U-4 or U-IV was a U-3-class submarine or U-boat built for and operated by the Austro-Hungarian Navy (German: Kaiserliche und Königliche Kriegsmarine or K.u.K. Kriegsmarine) before and during the First World War. The submarine was built as part of a plan to evaluate foreign submarine designs, and was the second of two boats of the class built by Germaniawerft of Kiel, Germany.

U-4 was authorized in 1906, begun in March 1907, launched in November 1908, and towed from Kiel to Pola in April 1909. The double-hulled submarine was just under 139 feet (42 m) long and displaced between 240 and 300 tonnes (260 and 330 short tons), depending on whether surfaced or submerged. The design of the submarine had poor diving qualities and several modifications to U-4's diving planes and fins occurred in her first years in the Austro-Hungarian Navy. Her armament, as built, consisted of two bow torpedo tubes with a supply of three torpedoes, but was supplemented with a deck gun, the first of which was added in 1915.

The boat was commissioned into the Austro-Hungarian Navy in August 1909, and served as a training boat—sometimes making as many as ten cruises a month—through the beginning of the First World War in 1914. At the start of that conflict, she was one of only four operational submarines in the Austro-Hungarian Navy U-boat fleet. Over the first year of the war, U-4 made several unsuccessful attacks on warships and captured several smaller vessels as prizes. In July 1915, she scored what Conway's All the World's Fighting Ships, 1906–1921 calls her greatest success when she torpedoed and sank the Italian armored cruiser Giuseppe Garibaldi, the largest ship hit by U-4 during the war.