"U-43"s fourth and final success on her fourth patrol took place on the morning of 17 July when she sank the 3,509-ton British merchant ship "Fellside", a straggler from convoy OA-184, about north-west of Bloody Foreland ("Cnoc Fola"), Donegal.The U-boat's first torpedo passed under the vessel, but the second struck the ship and caused her to sink within five minutes.