Nummer: 00309
| Area : | Western Area |
| Sea area : | Kattegat |
| Date of attack : | 24.09.1939 |
| Time of attack : | 10:37 |
| Nationality of U-boat : | German |
| U-boat : | U 4 |
| Commander : | Klot-Heydenfeldt |
| Grid : | AO 4146 |
| presumed target type : | Steam Freighter id |
| presumed tonnage : | 1500 BRT |
| presumed result : | sunk |
| Number of torpedoes/mines : | 3 |
| Used weapon(s) : | Torpedo(es) |
| Date of observation : | 24.09.1939 |
| Nationality of target : | Swedish |
| Actual type of target : | Steam Freighter |
| Name of target : | Gertrud Bratt |
| Year of launch : | 1927 |
| Actual tonnage : | 1510 BRT |
| Actual result : | sunk |
| Position of target : | 58.40n 09.52e |
