 "U-523" departed Kiel on 9 February 1943 and sailed out into the mid-Atlantic.On the morning of 19 March the 5,848 ton American merchant ship SS "Mathew Luckenbach", part of Convoy HX 229 en route to the UK from New York City, was hit by two torpedoes fired by .The crew of eight officers, 34 crewmen and 26 armed guards (the ship was armed with one gun, one gun, and eight 20 mm guns) abandoned ship in three lifeboats and two rafts, and were picked up later by .