Clancy did embellish a few things and speculated rather a bit to make an entertaining scenario.

All told, a good solid read, and accurate in a bunch of not-quite critical details, but don't lean too hard on the edges of the story.

Same with Red Storm Rising. Very well told, close to a solid "what if", but lots of little touches to make it entertaining as well.

It is ML depending on what we're calling ML. Is gradient descent/MLE ML? If yes, then the Dallas (the US sub) in Red October was using ML.