Nummer: 18313
| Area : | Western Area |
| Sea area : | English Channel |
| Date of attack : | 20.07.1944 |
| Time of attack : | 14:38 |
| Nationality of U-boat : | German |
| U-boat : | U 309 |
| Commander : | Mahrholz |
| Grid : | BF 3533 |
| presumed target type : | Steam Freighter |
| presumed tonnage : | 6800 BRT |
| presumed result : | damaged |
| Number of torpedoes/mines : | 3- |
| Used weapon(s) : | Torpedo with gyro-angle and zig-zaggig course |
| Convoy : | unknown |
| Actual tonnage : | ---- -- |
| Actual result : | hit not ascertained |
| Footnote : | U-309 fired a spread of three LTUs and heard a detonation after 9:30 min. |
| Convoy : | unknown |