Right now, the Queen Mary 2, launched last year, is the largest cruise ship afloat, weighing 150,000 tons. She's nearly four football fields long and carries about 3,800 passengers and crew. She may not hold that crown for long, however. Royal Caribbean is planning the Ultra-Voyager, expected to tip the scales at 160,000 tons and carry 4,000 plus. Both ships dwarf the puny Titanic — a mere 46,000 tons.

The average cruise vacationer is about 50 years old, with an above-average annual household income of $99,000 and has taken 3.3 trips. Most (83 percent) are married and have college educations (69 percent). However, more than 80 percent of U.S. adults have never been on a cruise. (If you're 43 years old, watch out: You're the hottest cruise prospect.)

— Source: Cruise Lines International Association.

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