Farnborough came into contact with SM U-68 off Britain's west coast on 22 March 1916. At approximately 07:00, U-68 fired a torpedo at Farnborough that narrowly missed the ship's bow. Farnborough continued the deception of being a merchant ship and continued at her same speed and course. At 07:20, U-68 surfaced about astern of Farnborough, moved to the ship's port quarter, and fired a shot across the Q-ship's bow.Messimer, pp. 86–87. Farnborough stopped, blew off steam, and launched a boat to simulate a surrender. As U-68 closed to , Farnborough raised the British White ensign, uncovered her guns and opened fire with three of her five 12-pounder guns. The British gunners scored several hits on the U-boat out of 21 rapidly fired rounds. As U-68 began to sink, Campbell steered Farnborough over U-68s location and dropped a depth charge that blew the bow of the submarine out of the water. This was the first use of the depth charge in action.Tarrant, p.27 As U-68 began going down by the stern, Farnboroughs gunners scored another five hits on the U-boat's conning tower. U-68 sank at position off Dingle in southern Ireland, with the loss of her entire crew of 38 men.
