 On 7 December "Iku-Turso" was sortied to intercept the Soviet freighter "Ivan Papanin" sailing from Stockholm.The submarine was informed of the departure time of the target and the likely route and so "Iku-Turso" patrolled in the international waters off Sandhamn and Svenska Högarne during the night.Unidentified patrol boats harassed the submarine and forced it to dive and by the time "Iku-Turso" was able to reach periscope depth there were no freighters in sight.