“Jaws” was a thrill to watch. Filming it, however, was another story.

In 1973, producers Richard D. Zanuck and David Brown purchased the film rights to Peter Benchley’s new novel “Jaws.” They handed directing duties to a 26-year-old Steven Spielberg, who had become an overnight success for his now-classic TV movie “Duel.”

Spielberg recruited his friend, TV writer Carl Gottlieb, to adapt the screenplay. Gottlieb famously promised, “If we do our jobs right, people will feel about going in the ocean the way they felt about taking a shower after ‘Psycho’.”

Spielberg stripped away most of the book’s subplots, believing the shark was the real star. To make the film seemingly more real, he cast relatively unknown actors: Roy Scheider as police chief Martin Brody, Richard Dreyfuss as marine biologist Matt Hooper and Robert Shaw as the crusty shark hunter, Quint.

Determined to shoot in the ocean instead of a Hollywood tank, Spielberg commissioned three pneumatically powered sharks. Constructed in California over five months by 40 effects technicians, the mechanical sharks could swim, thrash their tails, gnash their teeth and dive. Each was nicknamed “Bruce” after Spielberg’s lawyer, Bruce Ramer. Once completed, they were transported to Massachusetts for filming.

Each shark required 14 operators and was mounted on an underwater sled during filming. Spielberg chose Martha’s Vineyard for its shallow sandy seabed, gentle tides and unbroken horizon. Renamed Amity in the film, the village doubled as a fictional tourist town on Long Island’s south shore. 

In May 1974, Spielberg and his crew arrived with a $3.5 million budget and plans to finish filming in 55 days.

But chaos quickly followed. The mechanical sharks regularly malfunctioned: hoses burst, kelp clogged gears and sleds ran aground. Unpredictable weather and drifting sailboats caused frequent delays. Seasick actors and crew didn’t help.

Everybody complained. Frustrated crew members began referring to the project as “Flaws.” 

Filming finally wrapped after 159 days—more than double the original schedule—and nearly $5.5 million over budget. 

Spielberg later admitted, “I thought my career as a filmmaker was over.”

To Hollywood moguls, summer was considered a dumping ground for low-brow teen flicks. But that changed in June 1975 when Universal released Jaws, which became history’s first-ever summer movie blockbuster.

In just 10 days, the film recouped its entire production cost and went on to become the highest-grossing movie of all time until Star Wars dethroned it two years later.

And Spielberg? He never had to worry about his career again.