The German Type UE I submarine was an ocean-going single-hull submarine with saddle tanks built by AG Vulkan in Hamburg and Kaiserliche Werft Danzig. The Type UE I was equipped with two six-cylinder Benz engines for 900 horsepower (670 kW) for a surface top speed of 9.6 knots (17.8 km/h; 11.0 mph) to 10.6 knots (19.6 km/h; 12.2 mph). Armed with a single torpedo tube forward and aft, plus one 8.8 cm (3.5 in) SK L/30 deck gun (U-72 received a 10.5 cm (4.1 in) SK L/45 gun in 1917), its main weapon were the 38 mines in two minelaying tubes.