It's still dark out at this industrial port. Most passengers aboard the Oasis of the Seas are sound asleep in their staterooms.

But below deck the crew of one of the world's largest cruise ship is preparing to turn the vessel around. They have just ended a week-long voyage taking 6,222 people throughout the Caribbean. In just hours, another 6,114 will start their vacations.

Suitcases need to be unloaded and loaded. Piles of trash and recycling are removed and an entire week's worth of food for the passengers — and 2,193 crew members — needs to be loaded onboard.

The clock is ticking. There are just 10 hours to essentially empty and restock a small town. If that weren't enough, housekeeping needs to turn over 2,700 staterooms for the new guests.

"I'm amazed every single time you do it," says Raimund Gschaider, associate vice president for hotel operations at Royal Caribbean International. "It's an orchestration of all different operations. Everything needs to be fine-tuned down to the last minute."

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    By 6:30 a.m., the first of 25 trucks are lined up on the dock, ready to unload their goods.

    The Oasis and its sister ships — the ?Allure of the Seas and the soon-to-sail ?Harmony of the Seas — are the three largest passenger ships in the world. While many passengers remember the zipline, the onboard surfing machine or the 25 different dining establishments, it's really what happens below desk that amazes.

    When the Oasis leaves for a week-long voyage to the Caribbean, it takes everything needed. The islands visited don't have the quantity — or the quality — of supplies to meet the needs of the ship, Gschaider says.

    "In a hotel, you get your supplies on a daily basis. You're never tied into a limited timeframe," he adds. "For us, we only have one go at it."

    That means when the ship pulls away from the dock in Florida, it must have 10,272 new rolls of toilet paper, 7,397 pounds of cheese and 330 cases of pineapples onboard. Not to mention 1,000 new lightbulbs, 30 replacement TVs, 1,899 pounds of coffee and 23 gallons of hand sanitizer. Every week.

    Orders are based on past trends and slightly adjusted each week to account for the age and nationalities of those sailing. If there is a big sporting event — say the college basketball championship tournament — more beer and hot dogs might be purchased.

    Here's a look at some of the items on one sailing:

    — Lobster tails: 5,400

    — Ice cream cones: 21,000

    — Tomatoes: 8,800 pounds

    — Lettuce: 9,000 pounds

    — Potatoes: 14,800 pounds

    — Apples: 2,600 pounds

    — Bananas: 5,400 pounds

    — Eggs: 46,800

    — Milk: 2,622 gallons

    — Chicken: 19,723 pounds

    — Beef: 18,314 pounds

    — Fish: 7,070 pounds

    — Hot dogs: 10,680

    — Beer: 31,900 bottles and 900 cans

    — Soda: 16,900 cans

    — Vodka: 820 bottles

    — Whiskey: 179 bottles

    — Scotch: 293 bottles

    — Rum: 765 bottles

    — White wine: 3,360 bottles

    — Red wine: 2,776 bottles