"Open Water 3: Cage Dive" is the latest installment in a longstanding horror series — one that the original filmmakers never asked for.

More than 40 years after “Jaws” turned the fear of shark-infested waters into a classic horror trope, the concept keeps giving rise to new iterations, most recently with Liongate’s release of “Open Water 3: Cage Dive.” The low-budget project opens in limited theatrical release and VOD August 11, and it’s a curious outcome for what was a sensation at the 2003 Sundance Film Festival and became a $54 million worldwide hit.

At this point, the franchise carries no earmarks of its indie roots — OW3 is a gimmicky story about Australian tourists whose cage-diving excursion with Great Whites goes horribly wrong — but the team behind the original installment never expected the concept to last this long. They didn’t even consider it a horror film.

In 2002, filmmaker Chris Kentis and his wife, Laura Lau, wrapped a passion project that had consumed two years of effort. Based on a true story about scuba divers abandoned by their boat in the Great Barrier Reef, the microbudget production focused on the experiences of a couple (Daniel Travis and Blanchard Ryan) whose diving excursion takes a morbid turn when they resurface to find themselves alone in the ocean. The situation gets increasingly dire as sharks swarm in.

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Shot with consumer cameras in real shark-infested waters, the minimalist production generated a deep-seated terror out of the fleeting glimpses of sharks in the water and the characters’ mounting desperation, but its slow-burn approach focused as much on the couple’s dynamic as the threat to their lives. The gradual exposition made it a tough sell when the filmmakers submitted the movie to festivals.

“Every festival in existence rejected it,” Lau said in a recent interview with her husband. “It was sad. We were dismissed by so many people. I had been hiding rejection letters from Chris.”

Nevertheless, Kentis knew that the movie was having a tough time getting out there. “Every rejection was devastating,” he said, noting that the slow opening of the project and its lo-fi production values likely turned off many festivals. “You look at this submission and everyone’s unknown, the budget’s minuscule, and it looks like shit because that’s what we could afford.”

That changed in the fall, when then-Hamptons International Film Festival programming head Rajendra Roy received a VHS submission of “Open Water.” When he began watching the movie, it hadn’t been rewound, so he was immediately aware of the extreme tension that forms the film’s centerpiece: the protagonists frantically swimming about as ominous dorsal fins swirled around them.

“The first act of the film was super banal, and my guess was that the previous viewer gave up after 10 minutes,” said Roy, who’s now the chief film curator at MOMA. “I didn’t. Shit got good once they got in the water.”

Kentis was keen on keeping the movie’s perspective on the same plane as his characters, rather than attempting to film the sharks underwater. “What do you don’t see can be scarier than what you do,” he told IndieWire in 2004. “I take pride in the fact that we really wanted to treat the sharks differently than what I’ve seen in other films. Pretty much any film with a shark is kind of the same thing — somebody falls in the water and the shark rips them apart. We wanted to take a more realistic approach.”

When the movie premiered at the Hamptons, Kentis was nervous. He’d tried to transfer the movie to a film print, but was stuck with showing it on a lower-quality tape at the screening. “I assumed everybody hated it,” he said. Then, the movie landed a rave from Variety, and buzz started circulating; the filmmakers worked on a tighter cut of the movie and resubmitted to Sundance, which accepted “Open Water” for the 2003 edition, where it was the first sale out of the festival.

The experience was overwhelming for the filmmaking duo. “It was really one of those Sundance Cinderella stories,” Kentis said. “Our eyes were glazed over looking at all the movie stars, and then there was this whole bidding war for the movie, and we couldn’t believe the numbers. It’s just a huge thing to be hit with, a lot at once.”

Read More: IndieWire at the New York Premiere For ‘Open Water’

When Lionsgate picked up the movie for $2.5 million, Kentis and Lau faced another challenge. The studio wanted to give the movie a wide release and play up its horror qualities, which was never the couple’s intention. “It didn’t quite represent the movie,” Kentis said. “I still see it as a drama, with talking heads. It wasn’t within the ‘Jaws’ genre.”

Still, they went along with the release strategy. “I knew if we had sharks, there was something that could be exploited there,” Kentis said. “If we could get past the gatekeepers, it would work in our favor, because it’s a great story — look what these people did with no money on consumer cameras.” It paid off, with hype for the film building on the hysteria over the similarly micro-budgeted horror phenomenon “Blair Witch,” released just four years earlier. (A headline about “Open Water” in the Wall Street Journal labeled it “Blair Fish.”) Since Lionsgate had released both films, Kentis and Lau were eventually contacted by the “Blair Witch” directors and hit it off. “The connection was pretty strong,” Kentis said, “but they really started the whole found footage thing, and that wasn’t our film.”

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