For weeks, the cast and crew of “Jaws” kept hearing the same four words over their walkie-talkies while shooting the film’s climactic ocean battle. That familiar message terrified Steven Spielberg, 27 years old at the time, with only one theatrical feature to his name. If one of the production’s three animatronic great whites broke down, it could mean another wasted day. All the setbacks put the film more than 100 days behind schedule and doubled its budget to $8 million.

“We didn’t know how they were ever going to finish this movie,” remembers Jeffrey Kramer, who played a sheriff’s deputy in the film. “There were rumors all around the set that the studio was going to shut us down.”

Spielberg, who had been entrusted with turning Peter Benchley’s bestselling novel about a rampaging shark into a cinematic event, feared he’d be fired. Yet he was determined not to betray how much the pressure weighed on him.

“His nails were bitten to the stubs,” remembers Carl Gottlieb, the film’s co-writer. “But that was the only manifestation of his nerves. Steven knew he needed to lead by example. That meant concentrating on his job and keeping his cool even when everything around him was going to hell.”

And everything that could go to hell, did. Filming just off Martha’s Vineyard had been Spielberg’s idea. He thought making “Jaws” on the open water would give it authenticity. It turned out to be an agonizing ordeal. Boats filled with pleasure cruisers drifted into shots; the waves and weather were unpredictable, so maintaining continuity was nearly impossible; and everyone kept getting seasick. When they weren’t retching over the side of the boat, the actors oft