Stop that, Lawrence! The subject of today’s lecture is the German Naval four-wheel Enigma, known to them as Triton and to the Allies as Shark. Introduced on 2 February of last year (1942), it wasn’t until the recovery of the beached German U-boat U-559 on 30 October that Bletchley Park got the material they needed to break the code. A couple of weeks ago, on 13 December, Bletchley Park finally busted Shark, and the internal communications of the German Navy became an open book to the Allies once more.