Three large U-cruisers, designated Type 139, were ordered from Germaniawerft of Kiel, in August 1916. Displacing nearly 2,000 tons, and with a surface speed of 15 knots (28 km/h; 17 mph), they were armed with 24 torpedoes and two 15 cm deck guns, and had a cruising range of around 17,000 nautical miles (31,000 km; 20,000 mi). They carried a large enough complement to furnish captured vessels with prize crews and their intended purpose was to capture or destroy merchant ships on the surface; their large-calibre deck guns and comparatively high speed allowed them to engage even armed merchant vessels.[1]