David Kahn's
Seizing the Enigma is an excellent read on how the Allies used SIGINT to combat U-boat depredations. The victory in the Atlantic, mainly accomplished by summer of 1943, was not a matter of "chance". It was a matter of devoted investigation, as well as using aircraft (both land-based and shipborne) to close the Mid-Atlantic gap, and the simple hardy bravery of merchantmen sailing under various flags straight into an arena where not only subs were aiming at you, but often nature itself was hostile.
Link is
here for anyone interested in reading his book, which focuses on SIGINT rather than the more mundane difficulties faced by seamen sailing that crossing. (I have no affiliation, just grabbed the first link for the book itself).
As an aside, Kahn also crafted some of the most devilish crossword puzzles I've ever encountered, probably (in my opinion) due to his expertise in crypto. His grids are usually very open, and he seems to avoid key break-in signatures like rare letters (Z, K, X, etc), so you have a 25-letter answer that gives you very few tells at all. I don't think he does them any more, but for years he contributed to the NYT crossword, and in that hard puzzle-space stands out as one of the most difficult puzzle authors.