"It's safe to say that virtually every big yacht of distinction at one time or another passes through Fort Lauderdale, simply because it has one of the largest concentrations of skilled boat craftsmen in the world," says Bob Saxon of Campers & Nicholson, Inc., one of the world's top yacht brokerage and charter management firms.

Still, Saxon and others in the industry are awed by the ever-increasing size of yachts, which are generally defined as boats longer than 85 feet. "But anymore we refer to boats in the 85- to 100-foot range as 'starter yachts,'" says Saxon. "That shows you how crazy the scene has gotten as the boats get bigger and bigger. Just five or six years ago, you could feel pretty special if you had a 100-foot yacht. These days that marker is 200 feet. You go to Monaco in the summer or, say, St. Martin in the winter, and they are just wall-to-wall with 200- and 300-foot yachts. It's mind-boggling."

Indeed, Showboats International, which tracks such things, recently reported that there were more than 250 so-called "starter yachts" scheduled for 2005. That's almost double the number ordered as recently as 2001, when 139 were launched. And industry insiders say there are probably more than 50 yachts of more than 200 feet now under construction, a process that could take anywhere from three to five years.

Considered against other luxury purchases-jewelry, fancy cars, private planes, multiple vacation homes-yachts are surely the most indulgent, conspicuous and hardest to justify in terms of making an investment that will hold its value. Beyond the purchase price-figure at least $10 million for something guaranteed to draw attention (Larry Ellison's Octopus is said to have cost $250 million)-upkeep alone can cost millions of dollars a year. Most owners seldom use their yachts more than a month or so a year but must still pay a crew to keep them ready to go.

"Yachts are like racehorses," says Saxon. "It's not good to let them sit." That's why about 60 percent of all yacht owners put their vessels in charter service. It's not a money-making proposition so much as it is a way to keep the yacht in good working order and, with luck, recoup some of the costs.

And it's not as if the mega-yacht owners can entertain big crowds on their boats. Even the 300-foot-plus yachts have a legal capacity of only 12 guests plus crew; the same goes for many 100-foot yachts. That's because they must abide by international Safety of Lives at Sea (SOLAS) regulations, which require vessels carrying more than 12 passengers to follow much stricter safety and construction guidelines, essentially the same rules and specifications followed by big cruise ships.

So with all these caveats, what's the appeal of the mega-yacht?

"It's the private-island fantasy," says Showboat International's Gilbert. "It's self-contained luxury, secure and safe. And you can take it just about anywhere in the world."

It's also about exclusivity, a way for the ultra-wealthy to separate themselves from those who are merely rich.

"Yachts have always been about status," says broker Croke, who's with Fort Lauderdale-based Merle Wood and Associates, which specializes in yachts of 120 feet and more. "Not only are the yachts getting bigger, but the playthings associated with them are becoming fancier. Used to be you could have a yacht and not pay a great deal of attention to your tenders, as long as you had one. Not anymore. These days, if you have a 300-foot yacht and you take it, say, to Monaco, then you want a 100-foot chase boat to accompany it. That way when you and your friends want to bop off to St. Tropez for the day, you can hop on the chase boat, which will get you there in a hurry, rather than crank up the yacht, which might only go 17 knots. Everything just keeps getting bigger and better, and faster and more costly."

Indeed, the market for mega-yachts seems to be so strong that the only limiting factor, beyond where to keep them, is where to build them. All of the big yachts these days come from shipbuilding yards in Europe, primarily Germany, Holland, France and Italy. Shipbuilders in the United States haven't developed the capacity to go much beyond the 200-foot range. The largest yacht ever built in the U.S. is a 204-footer from a Seattle shipyard. One of Florida's leading yacht builders, Tampa-based Lazzara Yachts, has seen its offerings increase in size over the years from 68 feet to 80 feet to 106 feet. In 2004, Lazzara introduced its first 110-footer, with formal dining for 10, a sky lounge with a 42-inch plasma TV, and 16-cylinder engines that can push the craft at speeds up to 30 knots.