The A7V-U was a proposed evolution of the cumbersome Sturmpanzer A7V. The A7V became Germany;s first-ever locally-designed and produced combat tank and, while about 100 were ordered in early-1917, just twenty of these made it into the fighting of World War 1 (1914-1918). In service, and armed primary with a 57mm main gun while manned by no fewer than eighteen men, these proved hard to maneuver and unreliable and was therefore not deemed a success. The A7V-U was presented as its successor and attempted to right many of the wrongs inherent in the original A7V.
The Germans were not blind to the progress being made at their expense involving the rhomboidal British tanks. These steel beasts had a strong trench crossing capability and provided some protection against battlefield dangers all the while able to bring cannon and machine gun fire to bear. What they lacked as a true traversing turret with which to mount their primary armament in (the French FT-17 by Renault used this to good effect).
As such, German engineers adopted the British rhomboidal design for their own creation - the A7V-U. The tank held its track system outboard of a primary, centralized fighting cabin and ran over-and-under the side structures. The Holt tractor chassis of the A7V was retained in the body of the beast. Instead of a single 57mm fit, 2 x 57mm guns were installed and these in side-mounted sponsons as in the British tanks of the war. Over the fighting cabin was fitted a smaller superstructure with vision slits to help improve on the crew's situational awareness in the heat of battle. The complete design weighed some 40 tons.
A pilot vehicle was completed in June of 1918 before the end of the war (which arrived in the November 1918 Armistice). However, the tank was shown to possess a heavy bow, an abnormally high Center-of-Gravity (CoG) and overall weight issues which made for an imbalanced machine and impractical combat platform.
Despite these issues, the German government committed to twenty of the type in September of 1918 assuming the problems would be ironed out by the time production would ensue. However all that came to moot when the war ended in November of that year - effectively ending work on the A7V-U.