A Phoenix-size submarine is best berthed at a pier, but most minisubs are made to be launched from a yacht. In a pinch, they can even be brought to the nearest body of water on a trailer. And surprisingly, one doesn’t need to be certified to operate one, since the Coast Guard regards them as small boats, whether above or below water. Homeland security concerns do apply, however. In August 2007, the New York City police department arrested artist Philip Riley for drifting within 200 feet of the Queen Mary II in his replica of the first personal submarine, the Revolutionary War-era Turtle. New York Police Commissioner Ray Kelly downplayed the incident as “marine mischief.”

Fortunately, miniature submarine technology has progressed a great deal since the original one-person, human-propelled Turtle was built more than 230 years ago. World War II-era U-boats could dive to 750 feet, but at lower depths, the extreme pressure forced rivets to pop out of the hull. Modern personal submarines can reach that depth with ease. Chronic adventurer Steve Fossett had Hawkes start building him the Deep Flight Challenger, a 14-foot-long sub capable of cruising the bottom of the 36,000-foot-deep Mariana Trench for up to four hours. Hawkes was ready to begin initial water tests on the vessel in September when Fossett disappeared while flying somewhere over Nevada.

But regardless of whether the sub they’re piloting is barely floating on the surface, like Philip Riley’ eggish Turtle, or can reach the depths that Steve Fossett hoped to see, owners always like to take their boats down a little further. “What you want to look at,” says Ellis Adams of Seattle, who owns a two-seat (“we could put three in there if you’re really chummy”) diesel electric known as the S-101, “is always 100 feet deeper than your maximum depth rating.”

These days, it’s not difficult to find personal vessels. At September’s Monaco Yacht Fair, for instance, Dutch company U-Boat Worx displayed its new two-place electric. The tiny $246,000 submarine is nice enough for the yacht and can dive up to 160 feet below the sea. U.S. Submarine has its economical two-person Triton 1000 listed in this year’s Neiman Marcus holiday catalog. The $1.44 million price is such a bargain that Neiman Marcus has already sold out its entire stock. Okay, so the store had only one, but U.S. Submarines is building another just for the catalog.

Check the internet for good buys too. That’s where Ellis Adams is advertising his S-101. Selling point: It is painted like an Orca whale. Bidding starts at $640,000.