The Hunt for Red October (1990)

Plot:

A new, technologically-superior Soviet sub, the Red October, is heading for the U.S. coast under the command of Marko Ramius. The American government thinks Ramius is planning to attack. A lone CIA analyst has a different idea: he thinks Ramius is planning to defect, but he has only a few hours to find him and prove it--because the entire Russian naval and air commands are trying to find him, too. The hunt is on!