On April the 26th 2006, the German submarine U 32 (NATO S 182) arrived at the Spanish base of Rota. She had left the Bay if Eckernförde on April the 11th and cruised for two weeks submerged and with no contact whatsoever with the surface. This was an historical record for a submarine with a conventional propulsion. By conventional we meant simply non-nuclear. The propulsion system of the U 32 is actually a technological wonder that had been in development for decades: the hydrogen-oxygen fuel cell. The theory for this type of energy was developed early in the 20th Century and experiments were made for its application on submarines during World War II. The technology was not advanced enough back then and the most advanced submarines needed a snorkel to contact the surface to stay submerged for longer periods. After the war, nuclear reactors solved that problem aboard submarines and the development of fuel cells was no longer a priority.
In the early 1980s, the shipyard Howaldtswerke-Deutsche Werft (HDW) in Kiel started developing the idea again. By the end of the decade the Federal German Navy changed its construction plans for submarines, and a the development for a new class started. A long list of companies were involved in the design, that was basically centred around the shipyards HDW and Nordseewerke in Emden. A very long process started, involving the computer technic from the Norwegian Navy and the strong cooperation with the Italian Navy from 1994 on. The result was the submarine class 212 A. The work on the construction started in 1998. And on 2004 The first 4 submarines for the German Navy were almost fully tested. Further 4 were built for the Italian Navy under the name Todaro-class. This u-boats are the basis for the type 214, conceived by Germany for foreign navies. There have been many further developments on the class including current projects to build units for the Norwegian Navy.
The fact is that the class 212 A submarines are apparently the most silent and hard to detect submarines in the world.