Nummer: 20421
| Area : | Arctic Ocean |
| Date of attack : | 30.01.1944 |
| Time of attack : | 04:20 |
| Nationality of U-boat : | German |
| U-boat : | U 957 |
| Commander : | Schaar |
| Grid : | AB 6301 |
| presumed target type : | Destroyer |
| presumed result : | damaged |
| Number of torpedoes/mines : | 1 |
| Used weapon(s) : | Torpedo with preset course |
| Convoy : | JW.56B |
| Footnote : | U-957 heard a Gnat detonation after 4 min. |
| Convoy : | JW.56B |
| Route of convoy : | Loch Ewe - (Iceland) - Kola Fjord - (Arkhangelsk) |
| Remark to convoy : | Since Dec 1942, former PQ (counter traffic = RA) |