itchcock at sea. After the death of their son, John and Rea Ingram (Sam Neill and Nicole Kidman) board their boat the Saracen to cruise away their troubles off the Australian coast. A hysterical marine hitchhiker, Hughie (Billy Zane), claims he’s the sole survivor of the Orpheus, which is nearby and adrift. Food poisoning, he says. When John sails over to check out the Orpheus, Hughie morphs into a monster and hijacks Rea and the Saracen. Suddenly, it’s Kidman vs. Zane in the boat-length gloom. What begins as an effort to drown sorrows (Rea mourning her son) evolves into a primordial battle of the sexes. Phillip Noyce (who later directed Michael Caine in “The Ugly American”) pulls no punches in this nasty but wholly satisfying, smart thriller. Wild-eyed Zane is a knock-out.