U-571

[Jimbuna]

In reality, the submarine U-571 was never actually captured. The submarines U-559 and U-110 were the ones captured with the codebooks but by the British Navy in August 1941, four months before the United States entered the war. U-570 however was in fact a u-boat captured in late 1941 (by Britain) near Iceland, and subsequently deployed as HMS Graph until early 1944. Its appearance was used by the Royal Navy to fool German ships and submarines, and destroy them by surprise.

HMS Bulldog took the first enigma machine from a U-boat (U-110).

The British sailors climbed into the conning tower and began a search of the deserted submarine. The bookshelves still contained books of every description - navigation manuals, seamanship manuals, code books and signal books. The Bulldog's telegraphist pointed to an interesting piece of equipment that looked like a typewriter. This, along with all the books from the shelves, was transferred with utmost care to HMS Bulldog. It was important that everything was kept dry as the code books and signal books were printed in ink that disappeared if they were dropped in seawater.

http://www.iwm.org.uk/upload/package...a/enigma12.htm