Das Boot (1981)
Das Boot (, German meaning "The Boat") is a 1981 German epic war film written and directed by Wolfgang Petersen, produced by Günter Rohrbach, and starring Jürgen Prochnow, Herbert Grönemeyer, and Klaus Wennemann. It has been exhibited both as a theatrical release and as a TV miniseries, and in several different home video versions of various running times.
More at Wikipedia.