Navy chief of staff Admiral Juha Vauhkonen said that it is not possible to say with any certainty whether or not the underwater object detected in the Gulf of Finland on Monday was a submarine. The Admiral described the sighting as a category four case, meaning either a possible submarine or other underwater activity.
“An analysis of the data about the case will be available only within days, perhaps even weeks,” he said.
Vauhkonen said in the event that the object is found to be a submarine that violated Finnish waters, the matter would then be investigated by the Finnish Border Guard. He did not want to speculate on whether or not there were any similarities with a search for a submarine in the Stockholm archipelago by Swedish officials.
“Similar cases or situations have not occurred often. The last similar case in the Gulf of Finland dates back to 2004 and at the time we were forced to use warning depth charges on two separate occasions,” Vauhkonen noted.
First sighting Monday morning
The first indication of the presence of the underwater object came at 11.00 Monday morning and the second was made in the wee hours of Tuesday morning at 1.30 am. A warning was given to the object at 3.00 am, Vauhkonen said. However he did not disclose the size of the object or the depth at which it was detected.
The admiral said that the navy’s fixed surveillance network received a sound marking near Helsinki, which in turn led the operations centre to step up its underwater surveillance. The Navy also said that it issued an order to a territorial integrity vessel (AKT1) to deploy in the area where the sonar reading was detected.
“At the same time we sent out a request for coast guard boats in the Gulf of Finland to support the operation,” he added.
He said that the vessels arrived at the location of the object Monday afternoon around 2.30 to monitor the area. Later on in the afternoon a decision was made to also deploy an AKT2 vessel that was in port at the time.
The Navy said that the next sonar reading was detected at 1.30 Tuesday morning and continued readings were detected at 1.5-hour intervals. By this time the Navy had deployed the missile boat Hanko, the minelayer Uusimaa and the coast guard vessel Turva in the area. At around 03.00 am the captain of the Uusimaa decided to detonate a warning charge using low-impact depth charges.
Vauhkonen said that low-impact depth charges are used when there is sufficient evidence that there may be a submarine or other underwater activity in the area.
He concluded that the navy will continue to monitor the area using its fixed surveillance system.