On 9 July 1941, one week after Romania launched "Operation München" as part of "Operation Barbarossa", "Viscolul" and "Vijelia", together with the 250t-class torpedo boat "Năluca", engaged an enemy submarine near Mangalia. "Năluca" was the first to arrive at the scene and subsequently located and engaged the Soviet "Shchuka"-class submarine "Shch-206". In the first part of the battle, "Năluca" attacked the submarine with 20 mm rounds, but the latter submerged in order to escape. The Romanian torpedo boat subsequently used depth charges, being soon joined by the two motor torpedo boats. At 2:56 pm, the Soviet submarine was confirmed sunk by "Viscolul", none of her crew of 38 survived.