Not a movie I haven't seen, but a prior generation's iconic movie about the Titanic was 1958's A Night to Remember.
Interesting trivia, Bernard Fox appears in both the 1958 and the 1997 films. In the 1958 film he plays the young lookout, Frederick Fleet who first spotted the iceberg and in the 1997 film he plays Archibald Gracie IV, one of the wealthy passengers.