By Tom Stieghorst

GALVESTON, Texas — The 15-year-old Disney Magic will get new water features and more exciting slides in a September refurbishment that will be the biggest in the ship’s history.

The tone is set by the AquaDunk, a thrill slide in which riders step into a chamber, a door closes, the bottom falls out, and a plunge of 40 feet ensues before riders loop out over the ocean in an enclosed tube.

Also new will be “Twist N’ Spout,” which Disney executives describe as a family slide.

It will replace the tamer slide that goes into the Mickey Pool, which will be reborn as AquaLab after the renovations.

The general idea is to make the pool and water areas on the Disney Magic less age-specific, said Joe Lanzisero, senior creative vice president at Walt Disney Imagineering.

Lanzisero, the ship’s chief designer, led a preview tour of upgrades for a handful of journalists during a recent turnaround, using iPads to display renderings of the new features.

He said families on Disney ships prefer to stay together rather than be broken up into smaller units (although the Quiet Cove pool remains adults-only).

“We think now, between the family slide, the AquaLab, the thrill slide, that there should be something for everybody out there,” Lanzisero said.

Currently sailing from Galveston, the Disney Magic will spend the summer in the Mediterranean before its six-week drydock in Cadiz, Spain. Afterward, it will head to Miami to replace the Disney Wonder for the rest of 2013.

The pool deck will get the most noticeable makeover, but Disney is making changes throughout the ship to freshen it, change the predominant color scheme and replace some of the more dated concepts.

One area in need of an update, Lanzisero said, is the casual restaurant now called Parrot Cay, which has a quasi-tiki design. Under its new name, Carioca’s, it will get a more contemporary and “timeless” look, he said.

The children’s play areas will be redone, in part to accommodate Disney’s $4 billion acquisition of Marvel Entertainment, whose stable of superheroes, including the Avengers, will be represented for the first time at sea on the Disney Magic, Lanzisero said.

“We definitely wanted to do something with Marvel, especially for boys,” Lanzisero said.

Another big change will be additional space for Topsider, the upper-deck buffet restaurant, which will gain seats by enclosing some walkways and adjacent exterior deck areas. It will be rechristened Cabanas, given an Australian beach theme and have serving stations rather than cafeteria-style lines.

Two areas that won’t change much are Animator’s Palette and the adult restaurant Palo’s, which are both so popular that Disney plans to leave them essentially as they are.

The Magic will keep its art deco design elements but have a lighter, more aquatic color scheme.

The pool changes include building stairs beside the ship’s forward funnel to access the AquaDunk, a follow-on to the bigger AquaDuck water coaster developed for the Disney Dream and Fantasy.

The Disney Magic’s pool changes will also include adding waterplay features from newer Disney ships, such as bucket dumps and, for children under 3, an interactive Nephew’s Splash Zone with pop jets and bubblers similar to Nemo’s Reef on the Disney Dream.