What do you think about watching a film about a 77-year-old man wordlessly floundering around on a foundering boat for 106 minutes? Well if that man is Robert Redford, the director is young hotshot J.C. Chandor, and the film is “All Is Lost,” then you’re talking about an hour and a half of gripping, enthralling moviewatching. The plot: On a solo voyage in the Indian Ocean, an unnamed man (Redford) wakes to find his 39-foot yacht taking on water after a collision with a shipping container. His navigation equipment and radio are disabled and, without a motor, he works hard and cleverly to repair his boat and create a plan of action to save himself. But things get worse: he sails into a violent storm, which all but destroys the ship and his rations, and he’s left to float aimlessly under an unrelenting sun, circling sharks and dwindling supplies. Now the ever-resourceful sailor finds himself staring his mortality in the face. Redford gives a tour-de-force performance — indeed, this 77-year-old can handle himself well on the open seas.Extras: Commentary with writer-director-producer J.C. Chandor and producers Neal Dodson and Anna Gerb; “Big Film, Small Film” featurette; four vignettes: “The Story,” “The Filmmaker: J.C. Chandor,” “The Actor: Robert Redford” and “The Sound of All Is Lost”; “Preparing for the Storm” featurette with storyboards, VFX Reel, pre-shooting and time-lapse footage. Vitals: Director: J.C. Chandor. Stars: Robert Redford. 2013, CC, MPAA rating: PG-13, 106 min., Drama, Box office gross: $2.871 million, Lionsgate.