On 10 August, "Torsk" passed through the minefields in the Tsushima Strait, and the next day, she found and took aboard seven Japanese sailors from the merchant ship "Koue Maru" that had been sunk four days earlier. Later on the 11th, the submarine entered her patrol area. While patrolling off Dogo Island the next morning, she located a small freighter and sank her with a submerged torpedo attack. Off Ando Saki on 13 August, "Torsk" found several small fishing boats and another small freighter; she sank the latter and later that day, attempted to sink another cargo vessel in Wakasa Wan but her torpedoes missed.