TIME – For an industry rife with superstitions -it’s bad luck to rename ships, step aboard with your left foot, sight a redhead before you sail -Friday the 13th would seem an unlikely day for Royal Caribbean Cruises Ltd.’s (RCL) newest vessel, Oasis of the Seas, to make her debut arrival in Port Everglades, Florida.

Yet there she was, delayed two days by the stormy Atlantic on the way over from a shipyard in Finland, her 16 decks dwarfing the passing Miami skyline.

The US$1.4B megaship – the largest passenger ship ever made, with room for 6,296 guests – is nearly half again as big as the last biggest cruise ship, RCL’s Freedom of the Seas.

She’s as big as a supertanker or a container ship. Flatten the deck and you could launch F-18s off it. If you were sitting on the 20th floor of a high-rise next to the ship, you’d be able to talk to the sunbathers beside one of the pools.

The buzz has been just as big, says CruiseCritic.com’s editor Carolyn Spencer Brown. “I’ve been covering the industry for 14 years, and I’ve never seen people so excited about it. And these aren’t ship geeks.”

Filling a ship that humongous in the middle of an economic storm will take a lot more than ship geeks too. Across the industry, the number of passengers isn’t down, but sales and revenues are hurting because of discounts as deep as the blue seas.

RCL’s third-quarter net income fell to US$230 million, compared with last year’s US$411 million – while sales were US$1.8B, a 14% decrease.

“Average pricing is less than normal,” says Royal Caribbean International’s CEO, Adam Goldstein, “but we’re hopeful that we’ll recover pricing as quickly as possible.”

That’s important because a cruise-ship company owns its properties, unlike hotel companies that manage resorts, so RCL bears all the ships’ finance and carrying costs.

Oasis is a giant leisure machine, with more spas, pools, bars and activities than you could probably hit in a week. Royal Caribbean calls itself the Nation of Why Not–“as in, Why not try rock climbing?” says Goldstein.

“You don’t have to try surfing on the Flowrider, but it’s there.” You can get certified for scuba diving, take an ice-skating lesson, ride a zip line, play basketball, spar in a boxing ring, have a massage or see a version of the Broadway show Hairspray.

“They’re thinking outside the box,” says JoAnne Kochneff, owner of Travel by Gagnon, an independent agency in Grand Rapids, Mich., who has been on 60 cruises.

“For someone who thinks cruising is eating yourself sick at the buffet, sitting in a smoky casino or lounging by the pool, this ship will change their mind.”

To build the world’s biggest cruise ship RCL also had to build the world’s widest one, at 208 ft., and that change in naval architecture allowed the company to rethink what a cruise ship could be.

The upper decks have been split open in the middle of the ship to create a light-filled atrium with 12,000 plants tended by a full-time horticulturist. The open space, which the company calls Central Park, helps eliminate one of the worries that have caused travelers to shun ships–the fear of feeling cooped up.

“One of the ironies of cruising is that you’re out on the open seas,” says Brown, “yet spend all your time indoors.”

To secure a berth on this baby, you’ll need to shell out a minimum of US$1,529 for a seven-night cruise, which breaks down to US$218 a day. Not terrible for food, lodging and a Broadway show, not to mention the jazz revues, pools and aqua theater at your disposal.

A luxury suite can put you out US$7,609 a week, or US$1,087 per day.

Capacity across the industry has increased – 15 ships have launched this year, including Carnival’s Dream, and 12 set sail next year – so there are deals of less than US$60 per day out there.

“Hotels are shaking in their boots,” says Peter Yesawich, CEO of Y Partnership, a marketing firm, “and they should be.”

The design also allows the company to create areas throughout the ship that target specific demographics, such as families.

With a carousel on deck and buffets featuring animals carved from fruit, along with science labs, crafts centers and play theater, the company is trying to broaden its appeal.

But the goal is to lure not only parents but folks in their 40s with incomes of US$90,000 or more.

The industry isn’t quite there yet. According to the Cruise Lines International Association, the average cruiser’s age is 50-down from 56 in 2002 – but RCL is hoping Oasis cracks the code.

The search for younger customers not only drives the multiple activities, the super spas and the entertainment; it’s also driving the trend to shorter hops.

“Younger people aren’t going to sail for 24 days down the coast of South America,” says Yesawich.

“They don’t have that vacation time.” That’s one reason Oasis is based in the Caribbean and set up for seven-day voyages.

The cruise industry is basically a duopoly, with two players–Carnival, which owns Cunard, Holland America, Princess and Seabourn, among others, and Royal Caribbean, which also owns Celebrity and a few international lines–controlling 70% of the market.

There are three segments: contemporary, at US$200 and under per day; premium, US$250 and up; and luxury, at US$300 and above.

Royal Caribbean and Carnival operate mostly in the contemporary segment.

An estimated 13 million cruisers set sail in 2008, and the Cruise Lines International Association says cruising has grown worldwide 7% on average each year for the past 20 years.

But industry executives believe the market is underpenetrated – if so, it must be one of the few markets left that is–with only 20% of Americans having ever taken a cruise. Robin Farley, an analyst at UBS, says only 5% of vacationers opt for cruises each year, “just larger than the number of people who go to Branson, Mo.”

To cruise lines, every passenger is a potential ATM, which is why they’ll do anything to avoid leaving with empty berths. A full ship is important to the atmosphere, and to employees’ pockets, as tips are an important income boost.

If you board, you might buy drinks, spa treatments, snorkeling excursions or even airbrush tattoos. And gamble. So the 103% occupancy rates RCL has maintained through the recession have been worth the deep discounting.

“It’s been a frustrating time,” admits Goldstein, “but in this downturn it’s critical to satisfy our customers and hope they’ll come back and pay a higher price.”

Your ticket accounts for more than 70% of revenue–Royal Caribbean had sales of US$6.5B last year, with US$574 million in earnings–and ancillary charges, easily paid with a swipe of your onboard ID, made up about a quarter of those revenues.

In the past 10 years, the ships have added acupuncture, personal trainers, spinning classes and premium restaurants. One line even offers Botox treatments. The bigger the boat, the more opportunities, which is why Kochneff, for one, expects cruise companies to introduce more sea monsters like Oasis.

So far the industry has built up a good repeat business. Its core customers are a passionate bunch. “Cruising traditionally is about creating communities at sea,” says Brown, “and they do extend it to land.”

There is ample reward for the devotion. Frequent cruisers get cabin upgrades, cocktails with the captain. “People lust after this status,” says Yesawich.

A happy repeat customer is great, but “if ships are sailing full, you can only grow passenger volume at the rate you’re adding capacity,” says Farley. Yesawich sees some pent-up demand.

According to his yearly Travel Monitor survey, 40% of active travelers say they’re interested in taking a cruise in the next two years. “That’s a remarkable number,” he says. “Only a handful of places score higher. This business is going to explode.”

Matthew Jacob, a senior leisure analyst at Majestic Research, is more cautious.

“They’re trying to overcome people’s reluctance by making staterooms bigger and showing that they have more amenities than shuffleboard, with the onboard water parks,” says Jacob. “But when it comes down to it, you’re still on a ship. And that’s not for everybody. And it never will be.”

According to Yesawich, Oasis is tailor-made for first-timers–hence the park, the golf, the shows. “Getting them on the ship is the big hurdle,” says Brown.

“So the way to get a ton of them up the gangplank is to make it as much like land as possible.” Apparently, irony floats.