Why settle for a cabin cruiser when you can own a vessel that dives below the surface?U.S. Submarines builds personal luxury craft for Captain Nemo wannabes.

The most popular model, the $620,000 Triton 650, can be launched from a yacht to take two passengers as low as 650 feet. For spendthrift adventurers, there's the $20 million Seattle 1000. With five staterooms, a galley, a dining room, a living room, and floor-to-ceiling viewing portals, the 118-foot sub holds eight passengers and a crew of four, and is capable of eight-day transatlantic journeys. On the surface, it looks and operates like a conventional yacht, but when the weather gets rough it can simply slip beneath the waves.

U.S. Submarines, 954/467-9028;