EXCLUSIVE: Salty Secrets of 'Jaws' Revealed: How Production Went Over $3.5Million Budget, Broke Three Mechanical Sharks and Quickly Changed Two Scenes Last Minute

Blockbuster thriller Jaws captured the imagination of millions with its story of a killer great white shark terrorizing beachgoers at a small resort town – inspiring three sequels, Discovery Channel’s annual Shark Week programming block and the goofball spoof franchise Sharknado, RadarOnline.com can reveal.

Now we can reveal the secrets behind the making of the 1975 classic.

The film was based on the 1974 suspense novel by journalist Peter Benchley, who made a brief cameo in the movie as a news reporter.

Despite the success of the book and the film, Benchley said he came to regret writing such a sensational story about sharks. He thought his words encouraged excessive fear of the animals, and before his death in 2006, he became a vocal advocate for marine conservation.

Filmed on location on the island of Martha’s Vineyard in Massachusetts, Jaws was the first major feature to have scenes shot in the ocean – which took it well over its $3.5 million budget to cost the studio a stunning $8 million.

But all those extra clams weren’t such a bad deal in the end – the movie’s total box-office take was more than $470 million!

Director Steven Spielberg had nicknamed the movie’s three mechanical sharks Bruce – after his lawyer, Bruce Ramer – but when they kept breaking down, some disgruntled crew members began calling the film Flaws.

Adding to the production's money woes, the busted beasts cost $250,000 each.

Due to the repeated failure of the robot sharks, Spielberg cut back on the shark screen time and instead used John Williams’ ominous music to cue the impending arrival of the fierce man-eater.

In fact, the shark isn’t seen fully until one hour and 21 minutes into the two-hour movie.

"The film went from a Japanese Saturday matinee horror flick to more of a Hitchcock, the less-you-see-the-more-you-get thriller," Spielberg said.

Universal Pictures producers Richard Zanuck and David Brown wanted Spielberg to cast well-known actors, and Benchley said he pictured Paul Newman, Robert Redford and Steve McQueen headlining the movie.

But Spielberg was against hiring high-profile performers because, he said: "The superstar was gonna be the shark."

Many of the minor roles were played by real-life residents of Martha's Vineyard, including Deputy Hendricks, portrayed by local Jeffrey Kramer, who later became a television producer.

A string of actors were considered for the part of oceanographer Matt Hooper, including Jon Voight, Timothy Bottoms, Joel Grey and Jeff Bridges.

Spielberg’s friend George Lucas had just directed Richard Dreyfuss in American Graffiti and suggested he’d be suitable for Hooper. But Dreyfuss turned down the job – until he attended a screening of The Apprenticeship of Duddy Kravitz.

Dreyfuss was unhappy with his performance in the 1974 comedy, and he was worried he’d be unable to find more work, so he called Spielberg to accept the role in Jaws.

Roy Scheider got the part of Chief Martin Brody after eavesdropping on a conversation Spielberg was having at a Hollywood party, where he discussed having a shark leap out of the water onto a boat.

Scheider was fascinated and wanted to be part of the film, and since Spielberg loved his work in The French Connection, he later offered him the role.

Ben Hur legend Charlton Heston wanted to portray the police chief, but the director decided against it because of his “saving the day” parts in Airport 1975 and Earthquake.

Heston was so annoyed he vowed never to work with Spielberg and turned down his offer to play General Stilwell in 1941.

An early screenplay version had shark hunter Quint, portrayed by Robert Shaw, watching John Huston’s 1958 adaptation of Moby Dick.

But Gregory Peck – who plays Captain Ahab in that movie – owned the rights to Moby Dick and wouldn’t allow the Jaws filmmakers to use it, so the scene was cut.

Following test screenings, two scenes were changed.

Because the audience’s screams drowned out Scheider’s improvised quip: “You’re going to need a bigger boat,” his character’s reaction was lengthened and the volume of his line was increased.