Richard Fain, chairman and CEO, Royal Caribbean Cruises Ltd. officially takes ownership of Oasis of the Seas .

The hype has been enormous — seminars touting the retractable roofs, interior balconies, ziplining, aqua theater, an elevator bar and a promenade that features real grass the employees have to mow. Heck, they’ve even signed Rihanna to provide entertainment in December. But despite the webinars, CLIA classes, brochures and emails telling the travel industry between the lines that Royal Caribbean’s Oasis of the Seas will invigorate profits, it’s now looking like … well, hype.

Even the world’s largest ship can’t overcome the plummet in discretionary income to persuade folks to book sooner than a few weeks out in this fourth quarter. Travel agents are telling Cruise Week that at the end of October, there’s still plenty of vacancy on Oasis for Christmas and New Years sailings, even though the $1.5 billion vessel is the most talked about new cruise ship to come along in years, the publication points out. This includes everything from the inside Category Q spaces to balcony categories, although the suites at the top of the pricing chain are sold out.

It’s the same story for the first quarter of 2010, too: suites sell, while agents paddle to get vacationers to commit to the rest of the ship. That 40 percent additional space to entertain as many as 6,360 passengers per sailing may turn into 40 percent more booking headaches as the recession continues.

And since Oasis also carries another accolade — world’s most expensive cruise ship — slow bookings can’t be too welcome within the accounting department at Royal Caribbean, particularly with sister ship Allure of the Seas hot on its heels in the shipyards.  Oasis is scheduled from December 2009 to April 2010 to offer 7-night trips from Ft. Lauderdale to St. Thomas, St. Maarten and the Bahamas. Beginning in May, the itinerary changes to Haiti, Jamaica and Mexico out of Port Everglades, one of the few large enough at the moment to allow Oasis to dock.

“It’s in the DNA of our company, about every 10 years, to take more or less a fresh sheet of paper and create the greatest cruise ship in the world,” CEO Adam Goldstein has said. He’d better hope he also reinvents American travel habits in the next 12 days as well.

Photography: Royal Caribbean Cruises Ltd.