Johnny Depp scores a double hat trick with Captain Jack Sparrow in Pirates of the Caribbean: Dead Man's Chest.

The first "Pirates of the Caribbean" film was a $650 million worldwide success. So Disney, along with the film's cast and crew, signed on to make two more - at the same time. The first sequel, "Dead Man's Chest," arrives Friday.

The simultaneous-shooting strategy has worked for other blockbusters. Peter Jackson made all three "Lord of the Rings" movies in one epic effort for a cumulative box-office total of more than $3 billion. Robert Zemeckis doubled up on the "Back to the Future" sequels and released them a year apart, generating more than $575 million in global ticket sales.

Making two mega-budget movies at once brings benefits and challenges, says "Pirates" producer Jerry Bruckheimer. "We could never do this any other way," he says. 

The stars - Johnny Depp, Orlando Bloom and Keira Knightley - are in demand and busy with other projects. So is director Gore Verbinski. That means there would be a three- or four-year lag-time between sequels, Bruckheimer says, and "by then, the audience has moved on."

So when the filmmakers set out to make a "Pirates" sequel, they doubled-up their investment. Screenwriters Ted Elliott and Terry Rossio crafted a two-part story based on ideas introduced in the first film, Bruckheimer says. Verbinski and the actors committed to a year of work on the project, and Disney cut a hefty check.

"That's a gamble for (the studio)," Bruckheimer says. "You never know, sequels sometimes can fall flat on their face."

Disney "didn't have much apprehension at all," says spokesman Dennis Rice.

The fantastic chemistry between the filmmakers and the stars "gave us confidence that we had a bona fide franchise in the making," he says, "and it was worth taking the calculated risk."

Verbinski knew there were ample stories to explore in the "Pirates" world, he says, which inspired him to take on the two films.

Captain Jack Sparrow (Depp) has debts to settle and an un-piratelike honest streak to reconcile. Will Turner (Bloom) and Elizabeth Swann (Knightley) share a developing romance increasingly plagued by grown-up problems. The entire seafaring community is subject to the eradication of pirates as the East India Trading Co. dominates ocean commerce.

"There's really a bounty to be harvested here," Verbinski says. "It was daunting, but something I felt I had to jump into."

The real work was logistical, says the director, who coordinated the massive, multi-location shoot and kept track of the evolution of each of the characters.

"It's like having two of those 5,000-piece puzzles and they're all scattered together," he says. "Usually when you make a movie, there's some sort of light at the end of the tunnel. When you make two of them, there isn't."

Beginning in February 2005, shooting spanned several months and various Caribbean locations. The massive crew filmed scenes entirely out of order to maximize their time in each place, often spending the morning on the second movie and the afternoon on the third. Or vice versa.

"It can get very confusing," says Depp. "You've got to really keep track of the math."

The actors relied on Verbinski for that.

"He has it all in his head," Bloom says. "He's pretty amazing."

It was an exciting challenge, Verbinski says, adding "I didn't quite expect how exhausting it would be."

Next month, Verbinski and the "Pirates" cast and crew go back to work to put the finishing touches on the third "Pirates" installment. That one's due Memorial Day weekend, 2007.