 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. 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 (20.7 ft) and a draft of 3.79 metres (12.4 ft). 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 ( 1,220 shp; 910 kW) total ) for a maximum of 11 knots (20 km / h; 13 mph) when submerged. 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 cm (2.6 in) L / 26 deck gun.
