Nummer: 27813
| Area : | Pacific Ocean |
| Sea area : | US West Coast |
| Date of attack : | 24.12.1941 |
| Nationality of U-boat : | Japanese |
| U-boat : | I-21 |
| Commander : | Matsumura |
| presumed target type : | Tanker |
| presumed result : | damaged |
| Used weapon(s) : | Gunfire |
| Date of observation : | 23.12.1941 |
| Nationality of target : | American |
| Actual type of target : | Steam Tanker |
| Name of target : | Idaho |
| Year of launch : | 1919 |
| Actual tonnage : | 6418 BRT |
| Actual result : | damaged |
| Position of target : | 35n 121w |