According to a statement from the Finnish Navy, the audio signal picked up by anti-submarine surveillance in the western Gulf of Finland did not come from a submarine, but from either a cargo vessel or one of the Silja Line ferries.
The Navy’s detailed analysis of the audio sample thus rejects the theory that a submarine would have been in the area on Sunday.
A further two observations that were previously thought to have been caused by submarines are now believed by naval sources to have probably been from what is termed “natural causes”.
In the Archipelago Sea, close to the islet of Örö, a naval patrol vessel detected a radar image on Saturday. The vessel’s captain was so sure of the observation that he dropped warning depth charges.
On Sunday, meanwhile, civilians on shore near Porvoo saw something that was believed to be a submarine periscope. Coast Guard vessels and a helicopter searched but found nothing unusual.
