Robert Redford plays the unnamed hero, an old man sailing alone in the middle of the Indian Ocean. While he is asleep his boat is holed just above the waterline by a drifting cargo container. Enough water flows through to short out the boat’s electrical systems and destroy his communications equipment.
He calmly and methodically takes action to get clear of the hazard, repair the damage and try to get help, but a lot of things go wrong.
This movie is refreshingly free of the wishful thinking that permeates so many adventure stories. Nature appears stunningly powerful and sometimes annoyingly perverse. The hero is hardly superhuman. He’s in great physical shape for his age but he is no CGI-enhanced superman. He’s smart and resourceful but he makes a number of mistakes, sometimes because he is under pressure and sometime out of cantankerous stubbornness.
I know just a little bit about sailing–just enough that I was able to understand what the hero was trying to do. Someone who knows absolutely nothing about the subject might have trouble following the story. There’s no explanatory dialog of the form “I’m trying to do X in order to accomplish Y.” The hero is all alone and not given to talking to himself.
On the other hand it’s probably a good thing that I don’t know too much about sailing. I might have spent the whole movie picking on technical flaws. (In particular a lot of people seem to be asking why he didn’t have one of these.) Sometimes it may be good to have just the right amount of ignorance.