Nummer: 00901a
| Area : | Western Area |
| Sea area : | North Sea |
| Date of attack : | 21.12.1939 |
| Time of attack : | 07:25 |
| Nationality of U-boat : | German |
| U-boat : | U 21 |
| Commander : | Frauenheim |
| Grid : | AN 4577 |
| presumed target type : | Steam Freighter |
| presumed tonnage : | 4000 BRT |
| presumed result : | sunk |
| Number of torpedoes/mines : | 1 |
| Used weapon(s) : | Torpedo(es) |
| Date of observation : | 21.12.1939 |
| Nationality of target : | Swedish |
| Actual type of target : | Steam Freighter |
| Name of target : | Mars |
| Year of launch : | 1882 |
| Actual tonnage : | 1475 BRT |
| Actual result : | sunk |
| Position of target : | ENE May Island |
| Footnote : | "Mars" and "Carl Henkel" had both been damaged by mines laid from U-22/Jenisch on Dec.15th off Blyth, and were each sunk by a coup de grâce from U-21/Frauenheim on Dec.21st, 1939. |
| related attacks : | Angriff 1 |
| updated on: | 00.00.0000 |
| Remark: | May Island |