German Type UB I Submarine - Service

Service

During their trials the Type UB Is were found to be too small and too slow and had a reputation for being underpowered; one commander compared his Type UB I to a "sewing machine". According to authors R. H. Gibson and Maurice Prendergast in their 1931 book The German Submarine War, 1914–1918, the UBs did not have enough power to chase down steamers while surfaced and lacked the endurance to spend any extended amount of time underwater, exhausting their batteries after little over an hour's running. In-service use revealed another problem: with a single propeller shaft/engine combination, if either component failed, the U-boat was almost totally disabled.

Another reported problem with the Type UB Is was the tendency to break trim after the firing of torpedoes. The boats were equipped with compensating tanks designed to flood and offset the loss of the C/06 torpedo's 1,700-pound (770 kg) weight, but this system did not always function properly; as a result, when firing from periscope depth the boat could broach after firing or, if too much weight was taken on, plunge to the depths. When UB-15 torpedoed and sank Italian submarine Medusa in June 1915, the tank failed to properly compensate, forcing the entire crew to run to the stern to offset the trim imbalance.

Despite the problems, the "tin tadpoles", as the Germans referred to them, were in active service from March 1915 through the end of the war, with half of the twenty boats lost during the war. Boats of the class served in three navies: the German Imperial Navy, the Austro-Hungarian Navy, and the Bulgarian Navy. In German service, they served primarily in the Flanders Flotilla, the Baltic Flotilla, and the Constantinople Flotilla.