Canadian Navy Lake Ontario USO 1975

On September 4, 1975, HMCS Nipigon (DDE-266), a Canadian Navy destroyer escort operating in Lake Ontario for exercises, detected an unknown subsurface contact moving at approximately 75 knots — a speed far beyond any known submarine or underwater vehicle. The contact was tracked on sonar for 40 minutes as it maneuvered in the deep water of Lake Ontario. A US Navy research vessel in the area confirmed the sonar contact. Toward the end of the 40-minute tracking period, the contact surfaced and crew of the Nipigon observed a cylindrical object breach the water surface before ascending vertically and departing at high speed. The Toronto Coast Guard was notified. Given the proximity to the United States border and to a nuclear generating facility, the incident was reported to the FBI via the US Embassy in Ottawa. The FBI received a summary from Canadian Naval Intelligence. The case represents a documented transmedium encounter in a fresh-water body rather than ocean, an unusual geographic setting for such events.