Nummer: 18017
| Area : | Western Area |
| Sea area : | US East Coast |
| Date of attack : | 07.05.1944 |
| Time of attack : | 04:32 |
| Nationality of U-boat : | German |
| U-boat : | U 548 |
| Commander : | Zimmermann |
| Grid : | BB 6964 |
| presumed target type : | Destroyer |
| presumed result : | sunk |
| Used weapon(s) : | Acoustic homing torpedo (gnat) |
| Convoy : | ONM.234 |
| Date of observation : | 07.05.1944 |
| Nationality of target : | Canadian |
| Actual type of target : | Fregate |
| Name of target : | Valleyfield (K.329) |
| Year of launch : | 1930 |
| Actual tonnage : | 1445 ts |
| Actual result : | sunk |
| Position of target : | 46.03n 52.24w |
| Convoy : | ONM.234 |
| Route of convoy : | United Kingdom - North America |
| Remark to convoy : | 1st series: Jul 1941 to Mar 1943 ON and ONS combined, later ON mit continuing and ONS with new numbering (counter traffic HX and SC) |