Nummer: 13117
| Area : | Western Area |
| Sea area : | North Atlantic |
| Date of attack : | 30.10.1942 |
| Time of attack : | 23:28 |
| Nationality of U-boat : | German |
| U-boat : | U 409 |
| Commander : | Maßmann |
| Grid : | CF 9864 |
| presumed target type : | Steam Freighter |
| presumed tonnage : | 6000 BRT |
| presumed result : | sunk |
| Used weapon(s) : | Torpedo(es) |
| Convoy : | SL.125 |
| Date of observation : | 30.10.1942 |
| Time of observation : | 20:15 |
| Nationality of target : | British |
| Actual type of target : | Motor Freighter |
| Name of target : | Silverwillow |
| Year of launch : | 1930 |
| Actual tonnage : | 6373 BRT |
| Actual result : | sunk |
| Position of target : | 35.08n 16.44w |
| Convoy : | SL.125 |
| Route of convoy : | Sierra Leone (Freetown) - United Kingdom (Liverpool) |
| Remark to convoy : | Since Sep 1939; from May 1943 combined with MKS in Atlantic, counter traffic = OS. |