U-boat type XXI – was a revolutionary German submarine from World War II.
In the design of its hull was a major concern with the hydrodynamics: all structures that could cause some drag (like cannon) were eliminated. The result is that with this new format it has gained more speed when submerged.
Also offered better accommodation for its occupants. He had a freezer for storing food, shower and sink. So a crew that normally would spend weeks at sea on a mission to patrol without showering or shaving have better housing and work.
It was equipped with sophisticated electronic instruments: radar, passive sonar detectors and electromagnetic waves.

Its armament included 23 torpedoes or 17 mines torpedoes + 12. Had six launch tubes located in the bow. It was equipped with a hydraulic system that allowed recharge launch 18 torpedoes in under 20 minutes.

Its maximum speed at the surface was 15.5 knots (29km / h), 17.5 knots submerged (32Km / h) with maximum range of 15,500 nautical miles.