Ditch the jet, buy a sub?

The latest hot asset among the world's billionaire elite, according to a recent story on Yahoo! News, isn't the newest or biggest private jet. It's a submarine. The news service reported that Microsoft magnate Paul Allen, film director James Cameron and Russian oil billionaire Roman Abramovich are among the 100 or so owners of private submarines plying the seven seas.

Some of these vessels are truly submersible luxury yachts, equipped with gyms, Jacuzzis and gourmet galleys. But not all subs are leviathans. Virgin Atlantic airline founder Sir Richard Branson, who is perhaps equally famous for his private space-travel enterprise Virgin Galactic, is also reaching out to inner space, developing a one-man submarine capable of diving seven miles deep.

Large or small, however, private subs are designed to maintain their occupants' stealth. Abramovich threw down this gauntlet in a 2007 interview: "If you can find my submarine, it's yours."

Granted, a submarine is a pretty private place to be, but the term "private submarine" strikes me as borderline bizarre–"private" compared with what? Makes you wonder where the term "private jet" came from, as well. (I prefer "personal jet"–like personal computer–assuming we're discussing aircraft used primarily for non-business transportation.)

As you might expect, at any rate, Yahoo's story focused on the conspicuous consumption involved in owning a private submarine. The article mentioned an $80 million sticker price, but failed to provide detail. A brief Internet search revealed that small subs start at less than half a million dollars. Allen's 40-foot sub (which, incidentally, is painted yellow) reportedly cost $12 million–a drop in the ocean compared with what he has spent on his fleet of aircraft. U.S. Submarines, a builder of private subs, lists a 118-foot, two-deck midsize model at $25 million, including a 30-by-15-foot observation bridge, five staterooms, five baths (running water ought not to be a problem), two kitchens, a gym and a wine cellar (though I have to wonder about any submarine that has a cellar). U.S. Submarines' Seattle 1000 has a range of 3,000 nautical miles and you can remain submerged sipping Chardonnay for as long as 20 days.

Which brings up another key difference between submarines and jets. The former are not conceived of as practical means of transportation, but rather as a novel form of entertainment–kind of like an inside-out version of your own private Sea World. While there is no shortage of examples of exquisitely outfitted business jets, efficient transportation remains their primary purpose. An executive jet might be a fun way to get where you're going, but the primary mission is still just that: getting there–fast.

Speaking of fun, you've probably heard of the "mile-high club" for those who have made love in an airborne aircraft. It seems there may also be a "mile-deep club" (pardon the implication) for those making whoopee beneath the waves. But there's a problem not found 41,000 feet up in the sky. Dolphins have been known to bang their noses against the windows of submarines' observation decks when people inside are conducting club "business."

"Dolphins are easily excited when they sense people making love," said Bruce Jones, president and founder of U.S. Submarines. "They get jealous."

As odd as it sounds, Jones recommends installing curtains.