The Oasis of the Seas will meet its first obstacle on Saturday when it exits the Baltic Sea and must squeeze under the Great Belt Bridge, which is just 30cm taller than the ship - even after its telescopic smokestacks are lowered.
To be on the safe side, the ship - which rises about 20 stories high - will speed up so that it sinks deeper into the water when it passes below the span, said Lene Gebauer Thomsen, a spokeswoman for the operator of the Great Belt Bridge.
Once home, the $1.5 billion ($NZ2.07 billion) floating extravaganza will have more, if less visible, obstacles to duck: a sagging US economy, questions about the consumer appetite for luxury cruises and criticism that such sailing behemoths are damaging to the environment and diminish the experience of traveling.
Travel guide writer Arthur Frommer has railed against Oasis and other mega-ships he calls "floating resorts," suggesting that voyages on such large vessels are "a dumbing down of the cruise experience." Oasis of the Seas, which is nearly 40% larger than the industry's next-biggest ship, was conceived years before the economic downturn caused desperate cruise lines to slash prices to fill vacant berths.
"Obviously we did not want or anticipate she'd be born into the most significant economic downturn since the Depression," Royal Caribbean International President & CEO Adam Goldstein told The Associated Press in an interview earlier this month.
"Even in this environment, we're excited about her."
It sets sail as cruise lines clamour to increase capacity, adding newer - and bigger - ships to their fleets.
The Oasis of the Seas has 2700 cabins and can accommodate 6300 passengers and 2100 crew members. Company officials are banking that its novelty will help guarantee its success.
The enormous ship features various "neighbourhoods" - parks, squares and arenas with special themes. One of them will be a tropical environment, including palm trees and vines among the total 12,000 plants on board. They will be planted after the ship arrives in Fort Lauderdale.
In the stern, a 750-seat outdoor theater - modeled on an ancient Greek amphitheater - doubles as a swimming pool by day and an ocean front theater by night. The pool has a diving tower with spring boards and two 10-metre high-dive platforms. An indoor theater seats 1300.
Accommodations include loft cabins, with floor-to-ceiling windows, and 487-m luxury suites with balconies overlooking the sea or promenades.
One of the "neighbourhoods," named Central Park, features a square with boutiques, restaurants and bars, including a bar that moves up and down three decks, allowing customers to get on and off at different levels.
The liner also has four swimming pools, volleyball and basketball courts, and a youth zone with theme parks and nurseries for children.
Frommer suggests that such ships should never even leave port: "Who would know the difference?" "If the life on ship were a vital one, then you might justify building a ship so large," Frommer told the AP in an e-mail exchange.
"But when the activities programme consists largely of ziplines, surf-boarding, rock-climbing, a boxing ring, and imitations of Cirque de Soleil, when the lecture program deals with napkin-folding (the subject matter on other humongous ships operated by the same company), then there doesn't seem much appeal to well-read, intellectually curious people."
Paul Motter, editor of Cruisemates.com, has said that other critics have also complained that these huge ships flood ports of call, dumping 5000 people all at once in an area.
Motter said suites are sold out for most of the trips. Junior suites are mostly sold out and there is availability in inside, ocean view and balcony rooms.
He said ticket prices are still high for the Oasis, running $1299 ($NZ1800) to $4829, ($NZ6700) compared with $509 ($NZ705) to $1299 ($NZ1800) on the company's next most popular ship, Freedom of the Seas.
While environmentalists have said that the ship does not do enough to reduce air pollution and burns more fuel than a land-based resort, engineers at shipbuilder STX Finland said environmental considerations played an important part in planning the vessel. It dumps no sewage into the sea, reuses its waste water and consumes 25 percent less power than similar, but smaller, cruise liners.
"I would say this is the most environmentally friendly cruise ship to date," said Mikko Ilus, project engineer at the Turku yard. "It is much more efficient than other similar ships." The Oasis of the Seas is due to make its US debut on Nov. 20 at its home port, Port Everglades in Florida.
