Setting-This is the russian sub Red October. The setting has no major differences and they are both set in the North Atlantic during the time of the Cold War.
Characters-This is Jones a sonar genius who operates from the USS Dallas. There is a Russian spy on the Red October to keep her captain (Marko Ramius) in line. In the movie they do not show a Russian POV on him but in the book it is touched upon at the Kremlin.
Plot Events-In the movie Jack Ryan is dropped from a helicopter into the sea where he is pulled into the sub but in the book he is taken tot he Dallas in a rescue pod. Also in the movie the crew of the Red October in the movie rows rescue rafts to the U.S. ship the Interceptor. But in the book they are taken via the rescue sub. In the movie captain Ramius is shot in the shoulder but in the book he is shot in the leg.
Resolution-At the end of the movie the Russian sub hunting the Red October blows itself up but in the book the U.S. stages an explosion to simulate the Red October dying.