Wrong Amagi!
Amagi class as in the sister ship of Akagi. Idea I had for the original ships (Other then SMS Baden) was that they could modify ship hulls, but not build new ones. And yeah, Amagi was probably too badly damaged by the Kanto Earthquake to be towed...but hey.
The modern one was actually suggested by the Grand Chieftain of the native triubes (one of the three Triachs), He suggested that the three-deck configuration was like a representation of the nature of the nation as a whole.
In any case, the Battle Fleet: [Earler Baden refits included since she spanned all the periods of the fleet's history)
SMS Baden was the first of the fleet. She is identical to the Kaiserlichemarine ship and as such can be found under the Real Designs-Germany section of the Archives. She went through a series of refits.
SMS Baden-1940's Refit
In the aftermath of the battle with KMS Adm. Scheer, Baden was sent to America for a major refit. This included radar, additional antiaircraft armament, re-engining, and increased elevation for the main battery.
SMS Baden-1960's BBG Refit
As missiles became a more integral part of naval warfare, Baden was converted into a BBG design. The most notable technology introduced was the Mk15 GMLS. This was a modification of the standard Mk11 GMLS used by the USN. Modifications eventually allowed a wider range of missiles to be fired, including ASROC.
SMS Baden-1994 Refit
The last refit applied before she became a museum ship, this included updates to the radar, the new Fischadler Strike Missile, and lastly the experimental Lichtstrahl LADS. More a tech demonstrator then a proper SLEP refit, as even the Dreieinig engineers could only keep a ship operational for so long.
BBGN Lettow-Vorbeck 2012 Refit
Though called a comprehensive SLEP refit, this was actually a new construction vessel. The ship was utilized mostly as a training vessel, as it was obvious to even the most traditional Admirals that the Battleship's days lay in the past. Was also intended as a testbed for certain experimental weapons. (Advanced Fleet, will be shown later)
Next will be the Surface Combat Fleet, cruisers and destroyers.