Husøya, Norway: Frigate KNM Stavanger drops grenades on unknown sonar contact
On September 19, 1990, the Norwegian frigate KNM Stavanger had sonar contact with an unknown “U-boat” in the Norwegian Sea off Ona lighthouse, Husøya, dropped hand grenades and fired three Terne rockets.
Background
The KNM Stavanger had a sonar contact with an unknown “U-boat” in the Norwegian Sea off Ona lighthouse, Husøya, Norway. The ship sent international warning signals but received no response, so it dropped hand grenades into the water. At 5:30 p.m. it fired three Terne rockets. The sonar contact ended, and the next day the search was called off. The case is listed in Ole Jonny Brænne's survey of unidentified submarine objects in Norway in the International UFO Reporter. The account follows the entry in George M. Eberhart's chronology UFOs and Intelligence (CUFOS) and the sources cited there; it is not an independent determination by From Beyond Space.