After the Austro-Hungarian Navy had competitively evaluated three foreign submarine designs, it selected the Germaniawerft 506d design, also known as the Type UD, for its new U-7 class of five submarines.^[7] The Navy ordered five boats on 1 February 1913.^[8]

The U-7 class was seen by the Austro-Hungarian Navy as an improved version of its U-3 class, which was also a Germaniawerft design.^{[8][Note 1]} As designed for the Austro-Hungarian Navy, the boats were to displace 695 tonnes (684 long tons) on the surface and 885 tonnes (871 long tons) while submerged. The doubled-hulled boats were to be 69.50 metres (228 ft) long overall with a beam of 6.30 metres (20 ft 8 in) and a draft of 3.79 metres (12 ft 5 in). The Austrian specifications called for two shafts with twin diesel engines (2,300 metric horsepower (2,269 bhp; 1,692 kW) total) for surface running at up to 17 knots (31 km/h; 20 mph), and twin electric motors (1,240 PS (1,223 shp; 912 kW) total) for a maximum of 11 knots (20 km/h; 13 mph) when submerged.^[8] The boats were designed with five 45 cm (17.7 in) torpedo tubes; four located in the bow, one in the stern. The boats' armament was to also include a single 6.6 centimetres (2.6 in) L/26 deck gun.^[8]

U-8 and sister boat U-7 were both laid down on 1 November 1913, the first two boats of the class begun.^[9] Her construction was slated to be complete within 29 to 33 months.^[8]

Neither U-8 nor any of her sister boats were complete when World War I began in August 1914.^[9] With the boats under construction at Kiel, the Austrians became convinced that it would be impossible to take delivery of the boats, which would need to be towed into the Mediterranean past Gibraltar, a British territory.^{[8][Note 2]} As a result, U-8 and her four sisters were sold to the Imperial German Navy on 28 November 1914.^{[2][Note 3]}

U-8 was renumbered by the Germans as U-67 when her class was redesignated as the Type U 66. The Imperial German Navy had the submarines redesigned and reconstructed to German standards, which increased the surface displacement by 96 tonnes (94 long tons) and the submerged by 48 tonnes (47 long tons). The torpedo load was increased by a third, from 9 to 12, and the deck gun was upgraded from the 6.6 cm (2.6 in) gun originally specified to an 8.8 cm (3.5 in) Uk L/30 one.^[2]

U-67 was launched on 15 May 1915.^[2] On 4 August, SM U-67 was commissioned into the Imperial German Navy under the command of Kapitänleutnant Erich von Rosenberg-Grusczyski.^[1] On 28 October 1915, U-67 was assigned to the IV. U-Halbflotille in which she remained for the duration of the war.^[10]

In March 1916, Kapitänleutnant Hans Nieland replaced von Rosenberg-Grusczyski as the captain of U-67,^[1] and it was under his command that U-67 was most successful, sinking 17 ships with a combined a total of 39,720 gross register tons (GRT), while damaging a further four of 19,048 GRT.^[11] U-67's most successful month was April 1917, when she sank four ships of 15,223 GRT in a span of twelve days.^{[11][Note 4]}

Nieland was succeeded as commander of U-67 by Oberleutnant zur See Helmuth von Rabenau in December 1917. Under his command during the last eleven months of the war, U-67 sank no more ships. During her service career under three commanders, U-67 had completed thirteen war patrols. She was surrendered to the British on 20 November 1918, nine days after the Armistice, and broken up at Fareham in 1921.^[1]

• Helgason, Guðmundur. "WWI U-boats: U 67". German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. Retrieved 12 January 2015.
• Photos of cruises of German submarine U-54 in 1916-1918.
• A 44 min. German film from 1917 about a cruise of the German submarine U-35.
• Room 40: Archived 2018-10-15 at the Wayback Machine original documents, photos and maps about World War I German submarine warfare and British Room 40 Intelligence from The National Archives, Kew, Richmond, UK.