Nummer: 20911
| Area : | Arctic Ocean |
| Sea area : | North Norway |
| Date of attack : | 05.11.1944 |
| Time of attack : | 22:48 |
| Nationality of U-boat : | German |
| U-boat : | U 997 |
| Commander : | Lehmann |
| Grid : | AC 8265 |
| presumed target type : | Destroyer |
| presumed result : | sunk |
| Number of torpedoes/mines : | 1 |
| Used weapon(s) : | Acoustic homing torpedo (gnat) |
| Footnote : | U-997 heard a gnat detonation after 2:13 min. |