German submarine U-997

German submarine U-997 was a Type VIIC/41 U-boat built for Nazi Germany's Kriegsmarine for service during World War II. She was laid down on 7 December 1942 by Blohm & Voss, Hamburg as yard number 197, launched on 18 August 1943 and commissioned on 23 September 1943 under Oberleutnant zur See Hans Lehmann.

Service history
The boat's service career began on 23 September 1943 with the 5th Training Flotilla, followed by 12 months active service, with a succession of three flotillas, namely 9th Flotilla on 1 May 1944, then 13th Flotilla on 1 June 1944, and finally with 14th Flotilla on 1 March 1945.

Wolf packs
U-997 took part in seven wolfpacks, namely
 * Grimm (31 May – 6 June 1944)
 * Trutz (17 August – 1 September 1944)
 * Grimm (13 September – 1 October 1944)
 * Regenschirm (14 – 16 October 1944)
 * Panther (16 October – 8 November 1944)
 * Stier (21 November – 25 December 1944)
 * Hagen (15 – 21 March 1945)

Fate
U-997 was sunk by aircraft on 13 December 1945 in the North Atlantic, in position 55.83333°N, -10.08333°W, as part of Operation Deadlight.