Germany has commissioned its firstType 212 submarines. The first one, U-31, is now undergoing sea trials. Three more are under construction. These are special boats, as they possess fuel cells (for AIP, or Air Independent Propulsion) , which enable them to quietly operate underwater for weeks at a time. They still have diesel propulsion, but this is only used for surface travel. The 212's are also very quiet, quieter than most nuclear boats in service. This makes them an even match for a current nuclear boat equipped with better sensors. The 1,500 ton 212's are much smaller than nuclear boats (188 feet long, compared to 360 feet and 6,200 tons for the new U.S. Virginia class SSNs). The nuclear boats are used for a lot more than hunting other ships, and subs, while the 212's are mainly attack boats, and well designed and equipped for it. While Germany is an American ally, their development of fuel cell technology for subs, and use of these boats in their own navy, are making this technology mature, and eventually available to many more nations. These 212 boats are, expensive (about half a billion dollars each), but that's less than a third the cost of a nuclear boats. The 212's are also highly automated, requiring a crew of only 27. But with six torpedo tubes, and a dozen torpedoes (plus anti-ship missiles, launched from the tubes, as well as mines), they could be, in the wrong hands, a major threat to the U.S. fleet. Cheaper to buy, cheaper to run (you don't need as many skilled sailors for the crew) and very lethal, American admirals are watching very closely who the Germans export these boats to.