German submarine U-14 was a Type IIB U-boat of Nazi Germany's Kriegsmarine during World War II. It served with 3rd U-boat Flotilla from 18 January 1936 to 31 October 1939. U-14 completed six wartime patrols and sank nine ships totalling .
German Type IIB submarines were enlarged versions of the original Type IIs. U-14 had a displacement of when at the surface and while submerged. Officially, the standard tonnage was , however. The U-boat had a total length of , a pressure hull length of , a beam of , a height of , and a draught of . The submarine was powered by two MWM RS 127 S four-stroke, six-cylinder diesel engines of for cruising, two Siemens-Schuckert PG VV 322/36 double-acting electric motors producing a total of for use while submerged. She had two shafts and two propellers. The boat was capable of operating at depths of up to .
The submarine had a maximum surface speed of and a maximum submerged speed of . When submerged, the boat could operate for at ; when surfaced, she could travel at . U-14 was fitted with three torpedo tubes at the bow, five torpedoes or up to twelve Type A torpedo mines, and a anti-aircraft gun. The boat had a complement of twentyfive.
Early in the war, on 3 September 1939 in the evening, U-14 attacked a Polish submarine with one torpedo from a surface, and claimed to have sunk it. In reality the Polish submarine, , was not damaged as the torpedo launched by U-14 exploded prematurely. According to Jan Bartelski, the torpedo also missed the target.
After serving on six operational patrols, U-14 was used as a training boat and transferred to U-boat training flotillas, serving with the 23rd and 24th U-boat Flotillas until the end of the war. Despite the high casualties suffered by the Unterseebootwaffen (German submarine arm), U-14 suffered no known casualties during the war.
U-14 was scuttled on 5 May 1945 at Wilhelmshaven.