What a drag. Top Gun was about the best of the best flitting around the skies, kept aloft by a lonely impulse of delight. This list of History's Worst 5 Submarines catalogues the worst of the worst lumbering around in the briny deep. Such a vessel is a millstone dragging down the fortunes of its navy, its parent military, or the society that puts it to sea. Call it Bottom Gun. Now, it's possible to rank hardware, including submersibles and their armament, purely by technical characteristics. The crummiest piece of kit -- condemned by shoddy design, faulty construction work, or premature obsolescence -- is the bottom-feeder on such a list. In the case of submarines, then, tallying up speed, submerged endurance, acoustic properties, and kindred statistics offers a reputable way to proceed. But it tells only part of the story.