Well, I think there's one obvious answer to this question: Lothar-Guenther Buchheim's
Das Boot, the 1973 novel which inspired the film. It's available in various English translations, of which I have two: one by J. Maxwell Brownjohn (published in 1974) which reads very well but is a little 'loose' with the German, and another recently re-printed in the Cassell Military Paperbacks series (no translator named: just says 'this translation copyright Alfred A. Knopf 1975') which is a little more faithful to the German in some respects (e.g. present tense narration), but annoyingly not in others: all the measurements have been converted into Imperial units, which somewhat ruins the 'immersion' factor (another pun
).
But it's a great novel, whatever translation you can get hold of. Or if you can read German, even better!