Launched in 1914, completed in 1915, displacement 650 (surfaced)-784 (submerged) tons, horsepower 500 (surfaced)-840 (submerged) hp, oil-fired internal combustion machinery (surfaced)-electric machinery (submerged) and an armament of 4 torpedo tubes, 8 dropping gear and 2 small guns.
Source
Archive Dutch Naval Staff 1886-1942 (National Archive at the Hague, Netherlands) inventory number 155. Fleets (the British Empire and foreign countries) on 1 February 1923.