 "U-5" made an unsuccessful attack on a French battleship squadron off Punta Stilo on 3 November.In December, the ship's armament was augmented by a 3.7 cm/23 (1.5 in) quick-firing (QF) deck gun, and had her first radio receiver installed.In April 1915, Georg Ritter von Trapp assumed command of "U-5", and the following month, led the boat in sinking the French armored cruiser off Santa Maria di Leuca.