Nummer: 17305
| Area : | Western Area |
| Sea area : | North Atlantic |
| Date of attack : | 09.10.1943 |
| Time of attack : | 07:27 |
| Nationality of U-boat : | German |
| U-boat : | U 645 |
| Commander : | Ferro |
| Grid : | AL 0279 |
| presumed target type : | Steam Freighter |
| presumed tonnage : | 6500 BRT |
| presumed result : | sunk |
| Used weapon(s) : | Torpedo(es) |
| Convoy : | SC.143 |
| Date of observation : | 09.10.1943 |
| Time of observation : | 06:45 |
| Nationality of target : | American |
| Actual type of target : | Steam Freighter |
| Name of target : | Yorkmar |
| Year of launch : | 1919 |
| Actual tonnage : | 5612 BRT |
| Actual result : | sunk |
| Position of target : | 56.38n 20.30w |
| Convoy : | SC.143 |
| Route of convoy : | Sydney (Nova Scotia) - United Kingdom |
| Remark to convoy : | Slow (Atlantic) Convoys since Aug 1940, fast ones = HX, counter traffic = ON. |