Two hundred eighty-one years after the publication of "Robinson Crusoe" (and, perhaps more to the point, three decades after "Gilligan's Island"), the director and star of "Forrest Gump" reteam to update the venerable shipwreck survivor genre with the solidly crafted "Cast Away." Interwoven with timely observations about the centerless chaos of life in the modern world, helmer Robert Zemeckis' classy adventure drama has no shortage of compelling moments, though the straightforward concept starts to wear out its welcome a bit toward the end of the film's epic 143-minute running time.

   "Gump's" Tom Hanks stars as Chuck Noland (no-land, get it?), a time-obsessed FedEx executive dedicated to rush, rush, rushing packages around the world. Initially he's too busy even to spend Christmas with his girlfriend ("What Women Want's" Helen Hunt), but his carefully calibrated life is destroyed when a plane crash dumps him on an uninhabited island in the South Pacific. Without ready sources of essentials such as water, food and fire, the hero has to bone up on his Boy Scout skills fast if he wants to survive.

   Survive he does, of course, eventually transforming into a wild-bearded, wiry island rat reduced to carrying on extended conversations with a volleyball. The filmmakers pulled off the resulting radical change in Hanks' appearance by shutting down the production for a year so the actor could do a reverse "Raging Bull" and drop a startling amount of weight in the middle of the movie. This stunt lends an authenticity to Hanks' largely unspoken performance that, combined with Zemeckis' Spielberg-ian mastery of accessible cinematic storytelling, gives the island sequences a simple power future man-vs.-nature films will have a hard time topping. That said, Zemeckis and screenwriter William Broyles Jr. lose some momentum in the long-winded final act, which would have worked better if it had followed Hanks' example and gotten rid of some unneeded flab.    Starring Tom Hanks, Helen Hunt and Nick Searcy. Directed by Robert Zemeckis. Written by William Broyles Jr. Produced by Steve Starkey, Tom Hanks, Robert Zemeckis and Jack Rapke. A Fox release. Drama. Rated PG-13 for some intense images and action sequences. Running time: 143 min.