Unidentified "Gurtelpanzer-Kreuzer", c1892 (?)
There is no date on these drawings and I am not aware of any ships Germany built which resembled their particulars -- 3 stacks, twin rounded turrets. It resembles a battleship, but the type's name translates roughly as "armored belt cruiser". As the turrets resemble those of the Brandenburg class pre-dreadnoughts of 1893, it may date from that era. It appears to have 16 single 8.8cm guns (or maybe a mix of 8.8cm and 1.05cm), 4 above-water torpedo tubes, and 3 stacks. It may have been created as a variant on the Brandenburgs by exchanging the centerline turret found on those ships for additional boilers which in turn demanded a third stack, or perhaps this was a design created before a decision was made to build battleships instead of cruisers.
A rough measurement from the plan indicates a waterline length of 124 meters -- longer than the Brandenburgs (114m).
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Peter Klein writes to add:
From my point of view it does not resemble a battleship-design. As only sign for that I could identify the 2-shaft drive. It seems to be one of the design-studies which lead to the first German Armoured cruiser Fürst Bismarck. It still presents the general layout and appearance of the Kaiserin Augusta, but with two twin-mountings for heavier guns and of course an armoured belt. You're right if you compare the twin-mounts with those of the Brandenburg-class battleships. As those they resemble not turrets, but shields that turn with the gun's-plattform. Also the armoured coast-defence ships of the Siegfried type had similiar installations, but for just one 24cm gun in each of the three independent turning shields.
Cashan emails from Poland to point out the strong similarities to the Brandenburg class highlighted in this painting. Notice the distinctive "cheek" torpedo tubes common to the two classes.