It's really quite easy if you are a movie buff. If you have seen the movie, and both of you are old enough to have seen it, you will have seen the hull number and the name of one ship in the close up. The second ship is in the distance steaming into the scene and then they switch to the first ship for the closeup. One ship(closeup ship) is homeported on the east coast where the movie takes place and the second ship(distance shot) is on the west coast where they filmed some of the scenes. There is also a submarine and an ocean liner involved. That's the clues and of course you need to study Coast Guard History.