Nummer: 03504
| Area : | Western Area |
| Sea area : | North Atlantic |
| Date of attack : | 29.10.1940 |
| Time of attack : | 22:00 |
| Nationality of U-boat : | German |
| U-boat : | U 31 |
| Commander : | Prellberg |
| Grid : | AL 3880 |
| presumed target type : | Steam Freighter |
| presumed result : | sunk |
| Used weapon(s) : | Torpedo coup de grâce |
| Nationality of target : | British |
| Actual type of target : | Steam Freighter |
| Name of target : | Matina |
| Year of launch : | 1929 |
| Actual tonnage : | 5389 BRT |
| Actual result : | sunk |
| Footnote : | U-28 did not observe "Matina" going down. So the wreck sunk by U-31 on Oct.29th very probably was "Matina". |