German submarine U-559

30 October 1942: a sinking boat in the eastern Mediterranean

British aircraft and warships located and attacked U-559 in the eastern Mediterranean on 30 October 1942, eventually forcing the damaged submarine to the surface. Its commander, Hans Heidtmann, abandoned it with his surviving crew.

Lieutenant Anthony Fasson, Able Seaman Colin Grazier and Tommy Brown — a 16-year-old NAAFI canteen assistant, not a Royal Navy seaman — boarded from the destroyer HMS Petard and passed secret documents out to the waiting boat.

U-559 sank while Fasson and Grazier were still below deck, killing both men. Brown escaped with the recovered material.

What came out, and what did not

The recovered documents included the German Weather Short Code Book and Short Signal Book. The Enigma machine itself was not recovered; the submarine sank before it could be brought out.

The papers reached Bletchley Park on 24 November, twenty-five days after the boarding, and were used to regain access to the four-rotor U-boat cipher known as Shark.

What the prize was actually worth

This was not the first Allied success against Enigma. Its particular importance was helping overcome the 1942 blackout in Shark.

The documents supplied codebreaking aids and likely message cribs. Possessing them did not make every German naval message automatically readable.