During World War II, novelist Ernest Hemingway took a very hands-on approach while performing his patriotic duties--risking his life and literary legacy on the open waters around Cuba.

According to a story in The Daily Beast, Hemingway took his Cuba U-boat patrols very seriously: "If he spotted a U-boat, not only would he call for backup, he wanted to attack the sub himself. So he took some hand grenades and Thompson machine guns with him on his boat. Of course, trying to attack one of the subs was suicidal. If he had tried--if he'd gotten alongside the sub--U-boat captains would have sunk him."

The article was written by Terry Mort, author of the new book, "The Hemingway Patrols: Ernest Hemingway and His Hunt for U-Boats." It was part of The Daily Beast's new feature, "Just the Fact," interviewing authors about an unexpected fact in their historical books--a useful introduction to any new title.