The movie is fun, but leaves out a lot. What it keeps in, though, follows the book pretty well.
If you like Monsarrat's fiction, here's a book with some of his short stories, and the truth about The Cruel Sea, including the real name of HMS Compass Rose: http://www.subsim.com/radioroom/show...9&postcount=90
those short stories are great! I read them a couple of years ago.