German submarine U-17 was a Type IIB U-boat of Nazi Germany's Kriegsmarine. It was built in Germaniawerft, Kiel, where it was laid down on 1 July 1935 and commissioned on 3 December 1935, under the command of Werner Fresdorf.
German Type IIB submarines were enlarged versions of the original Type IIs. U-17 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. (All the photos only show one propeller) 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-17 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.
Its career consisted of four patrols, all served while under the 1st U-boat Flotilla where it sank three ships for a total of . Later in the war it served under the 22nd U-boat Flotilla as a training boat, including Oberleutnant zur See Walter Sitek as an instructor. Sitek had previously avoided imprisonment after the disabling and sinking of by in February 1942. He swam to Pico Island in the Azores, made his way through neutral Spain and returned to the Kriegsmarine to serve as an instructor on U-17, , and .
On 5 May 1945 U-17 was scuttled at Wilhelmshaven at the western entrance of the Raeder lock.