TORONTO -- The legendary Hercules may be one powerful character, but he's about to get blown out of the water -- ever so gently, mind you -- by a good-natured cowpoke and a high-tech space ranger.

Disney Cruise Line has featured a Broadway-style stage show called "Hercules: The Muse-ical" as part of the live entertainment lineup on one or both of its ships since they were launched in the late 1990s. On one ship, the Magic, Hercules was replaced in 2005 by a show called "Twice Charmed," which provides a new spin on the traditional Cinderella story.

Now it's almost time for the mythical Greek hero to walk the plank on Disney's other ship, the Wonder. Taking his place will be an elaborate new production called "Toy Story: The Musical," based on Disney's groundbreaking and wildly popular Toy Story movies. A troupe of about 20 actors, singers and dancers has been rehearsing here since shortly after Thanksgiving, and the show is tentatively scheduled to open aboard the Wonder during a cruise in late March.

In mid-December, a number of Disney executives and creative team members from Los Angeles and Orlando converged on the Queen Street rehearsal facilities in downtown Toronto to watch a partial run-through and to talk about the challenges of adapting an animated movie into a musical production within the limiting confines of a cruise ship.

"There's no doubt that Hercules will be missed," conceded Jim Urry, vice president of entertainment for the cruise line. "Passengers tell us they love it. But sometimes you have to take a chance and change things. If the project you're working on has no risk, then it won't provide much reward, either."

"It's a dilemma," agreed Tom McAlpin, DCL's president. "We have more repeat travelers, and some don't necessarily want to see the same shows on every cruise."

Both Disney cruise ships sail to the Caribbean from Florida's Port Canaveral, with the Magic taking seven-day cruises and the Wonder alternating three- and four-day trips.

With only two ships, Disney is among the smallest cruise lines in the business, but because it's owned by an entertainment colossus, it places more emphasis on top-notch shipboard productions than many traditional cruise lines. And its passengers may simply expect more from Disney in entertainment.

"The greatest strength for Disney is its brand," said Anne Hamburger, executive vice president of Disney Creative Entertainment. "But the greatest challenge for Disney is also its brand."

Ms. Hamburger, an award-winning independent Broadway producer, was hired by Disney seven years ago to oversee the development of major stage shows, parades and other events at its worldwide parks and aboard its cruise ships. She said she relishes the opportunity to introduce live theater to audiences that have never seen it before -- both adults and children -- and she's adapted to the trade-offs required when working for a big corporation.

"When I was on my own, I had total artistic freedom, but it was very wearing, always working to raise money," she said. "At Disney, when they believe in what you're doing, they fund it properly."

Among the many new productions Ms. Hamburger has engineered for Disney was "Finding Nemo: The Musical," which premiered at Disney's Animal Kingdom in 2006. It was that show that helped pave the way for "Toy Story: The Musical."

"It was the first time we tried making a non-musical story into a musical, and we had such success with it," Hamburger said. "That's what led us to this."

The stage version of Toy Story has much the same plot as the original movie and includes most of the same characters: Woody, the cowboy; Buzz Lightyear, the space ranger; Woody's girlfriend, Bo Peep; Mr. Potato Head; Slinky the dachshund; Rex the dinosaur; Hamm the pig; the green toy soldiers and the red monkeys.

Several of the characters are portrayed by actors hidden inside oversized, inflatable puppets, and their lines are prerecorded. But Woody, Buzz and Bo Peep's faces are visible, and their words and songs are performed live.

Integrating the live and recorded elements of the production is no easy task, according to director Stefan Novinski, because it requires precise timing. But he added that as the actors become more proficient in operating their puppets, distinct personalities -- the puppets' personalities, that is -- have begun to emerge.

"We're discovering the range of the puppets, and it keeps improving as we go," Mr. Novinski said. "It's like rehearsing a show while the actors are taking acting lessons."

Many of the costumes are still being prepared, and the most complex one is Buzz Lightyear's space ranger suit, said costume designer Ann Closs-Farley. It includes flashing lights, a moveable transparent dome and retractable wings. And the outfit is surprisingly versatile, she added, suitable for wearing by both 6-foot-5 Noel Douglas Orput, who plays Buzz, and his understudy, who is just 5-foot-3.

Among the more formidable challenges for Ms. Hamburger's creative team was putting together a lavish, Broadway-style production within the severely limited space that's available on board a cruise ship. Not only are the backstage areas and wings smaller than those of a standard theater, but also the props and set pieces must share storage space with those from two other onboard productions, Disney Dreams and The Golden Mickeys.

Those problems were minimized by creating props that could be folded up or be deflated. Also, like other live Disney productions, "Toy Story: The Musical" relies heavily on lighting and video animated projections.

In developing a new stage show for the cruise line, there's one Disney title that would seem to have been a natural for a seagoing venue -- the hugely popular "Pirates of the Caribbean" franchise. So why did DCL go with Toy Story and not Pirates?

"I figured you might ask that," said Matt Almos, creative director for Toy Story. "The truth is we've got a number of 'blue sky projects' that we're kicking around for the future, and yes, one of them is a Pirates adaptation.

"But Pirates has a lot of action scenes, and those are very tough to stage. We haven't cracked it just yet. But I wouldn't be surprised if someday we do."

That may happen by the time the cruise line has taken delivery of the two new ships it's had on order for the past year. The vessels, both about a third larger than the Magic and Wonder, are due to be added to the Disney fleet in 2011 and 2012.

Until then, DCL president McAlpin said he thinks that current passengers will be more than pleased with the new Toy Story musical aboard the Wonder.

"Our guests have high expectations, and we don't plan to disappoint them," he said. "They're going to get a real Disney show."

For more information on Disney cruises, call 1-800-951-3532 or check online at www.disneycruise.com.