Writer Edmund H. North worked closely with Forester's story, compressing events and time lines to make the plot taut. Along with the director, he decided to use a documentary-style technique, switching back-and-forth from a fairly insular war room to action taking place on remote battleships. The action is made more realistic when the human element of men in a game of wits and nerves is involved. The use of Edward R. Murrow reprising his wartime broadcasts from London also lends an air of authenticity and near-documentary feel. The film credits identify the actual Director of Operations as Capt. R. A. B. Edwards and "Capt. Shepard" as fictional. The Shepard-Davis interplay added human interest to the storyline.