 On 10 August , U @-@ 3 departed from Cattaro for what would be her final time for a patrol north of Brindisi . Two days later , while returning to Cattaro from the Straits of Otranto , U @-@ 3 launched a torpedo attack on the Italian armed merchant cruiser Citta di Catania . The torpedoes missed their mark and , in the ensuing action , U @-@ 3 was rammed by Citta di Catania , which destroyed the U @-@ boat 's periscope . When she attempted to surface , she was shelled by the escorting destroyers . She submerged to escape the artillery but was further damaged by a depth charge attack from the French destroyer Bisson while resting on the seabed . When U @-@ 3 surfaced the following day , she was shelled and sunk by Bisson . Fourteen of her crew were saved and captured , but seven died in the attack , including her commander , Linienschiffsleutnant Karl Strnad . U @-@ 3 had no successes during the war . 
