The Bedford Incident

One to see.

Wikipedia:

The Bedford Incident is a 1965 AngloAmerican Cold War film starring Richard Widmark and Sidney Poitier, and co-produced by Richard Widmark. The cast also features Eric Portman, James MacArthur, Martin Balsam and Wally Cox, as well as early appearances by Donald Sutherland and Ed Bishop. The screenplay by James Poe is based on the 1963 book by Mark Rascovich. This in turn was patterned after Herman Melville‘s Moby-Dick; at one point in the film the captain is advised he is “no longer hunting whales”.