The German Navy has six modern Type 212 submarines and since mid-December none of them are available for service. One damaged its steering mechanism on December 19th when U-35 struck a rock off Norway. The other five 212s are either undergoing repairs or maintenance or waiting for a dry dock to become available for essential work. There were other problems, similar to those that have kept many German warplanes and armored vehicles out of action since the 1990s. That was a lack of spare parts.
Defense spending was sharply cut in the 1990s. This was the “peace dividend”, the expected savings from the demise of the Soviet Union and its enormous military (including the second largest fleet on the planet.) The Type 212s entered service during this period and the failure to buy sufficient spare parts soon led to subs being sidelined until the spares could be manufactured. In some cases spares were obtained by taking components from subs sidelined for something else so that two subs would not be out of action. But this was more expensive and the situation just kept getting worse until there were no subs available for service and that situation won’t be rectified until early 2018 and won’t improve much until the navy gets a lot more money for spares and maintenance.
Germany could use its U-Boats right now because they provided a major threat to increasingly aggressive Russian warships in the Baltic and North Sea. That was always the intent, even though the 212s were developed simply to replace the Cold War era Type 209s and keep a prosperous export business (subs) going. In late 2005 Germany commissioned its first Type 212 submarine, U-31. This was quickly followed by U-32 and two more in 2006 and 2007. Two more entered service in 2015 and 2016. Another two were planned but never ordered. Italy also has four Type 212s.
Type 212s are special boats, as they were among the first use 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 1,450 ton 212's are much smaller than nuclear boats (57 meters/188 feet long, compared to twice as long 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 always paid attention to who the Germans export these boats to. Most of the exports are the less expensive Type 2014, which are 212s without a lot of the highly classified tech.