Nummer: 23811a
| Area : | Mediterranean |
| Sea area : | Western Mediterranean |
| Date of attack : | 13.11.1942 |
| Time of attack : | 06:15 |
| Nationality of U-boat : | German |
| U-boat : | U 431 |
| Commander : | Dommes |
| Grid : | CH 8324 |
| presumed target type : | Destroyer |
| presumed tonnage : | 1870 ts |
| presumed result : | sunk |
| Used weapon(s) : | Torpedo(es) |
| Convoy : | Force R |
| Date of observation : | 13.11.1942 |
| Nationality of target : | Dutch |
| Actual type of target : | Destroyer |
| Name of target : | Isaac Sweers |
| Year of launch : | 1940 |
| Actual tonnage : | 1628 ts |
| Actual result : | sunk |
| Position of target : | 37.23n 02.12e |
| Footnote : | U-431 observed the sinking on an destroyer after two hits, and saw a tanker afire and stopped after one hit. The missed tanker was "Dingledale". |
| related attacks : | Angriff 1 |
| Convoy : | Force R |
| Route of convoy : | Mediterranean: RN Task Force |
| Remark to convoy : | Short-time Task Forces of the Royal Navy |