A design study for a compact German battleship

I have a pencil sketch for a compact battleship, with the notation that the full load displacement was 30,000 tons. The two turrets, situated forward, one superfiring, seem to have 16.5in guns, from the size. The layout and length are clearly defined. I estimated the other specifications, and found that the basic concept was sound, as I was easily able to get the Springsharp design to work. it does require lightweight machinery. This is the report:

Ger/BB/1915 Design Study, Enter country Enter ship type laid down 1915 (Engine 1931)

Displacement:
 28,012 t light; 29,224 t standard; 30,000 t normal; 30,621 t full load

Dimensions: Length overall / water x beam x draught
 620.94 ft / 620.00 ft x 105.00 ft x 30.00 ft (normal load)
 189.26 m / 188.98 m x 32.00 m  x 9.14 m

Armament:
      6 - 16.50" / 419 mm guns (2x3 guns), 2,246.06lbs / 1,018.80kg shells, 1915 Model
   Breech loading guns in turrets (on barbettes)
   on centreline, all forward, 1 raised mount - superfiring
      16 - 5.00" / 127 mm guns in single mounts, 62.50lbs / 28.35kg shells, 1915 Model
   Quick firing guns in deck mounts with hoists
   on side, all amidships, 4 raised mounts - superfiring
 Weight of broadside 14,476 lbs / 6,566 kg
 Shells per gun, main battery: 75

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 14.0" / 356 mm 340.00 ft / 103.63 m 17.00 ft / 5.18 m
 Ends: Unarmoured
   Main Belt covers 84 % of normal length

   - Torpedo Bulkhead:
  3.00" / 76 mm 340.00 ft / 103.63 m 30.00 ft / 9.14 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 16.0" / 406 mm 9.00" / 229 mm  14.0" / 356 mm
 2nd: 2.00" / 51 mm       -         -

   - Armour deck: 4.00" / 102 mm, Conning tower: 14.00" / 356 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 4 shafts, 48,081 shp / 35,869 Kw = 23.00 kts
 Range 4,500nm at 12.00 kts
 Bunker at max displacement = 1,397 tons

Complement:
 1,139 - 1,481

Cost:
 £3.930 million / $15.719 million

Distribution of weights at normal displacement:
 Armament: 1,810 tons, 6.0 %
 Armour: 11,171 tons, 37.2 %
    - Belts: 3,714 tons, 12.4 %
    - Torpedo bulkhead: 1,132 tons, 3.8 %
    - Armament: 2,710 tons, 9.0 %
    - Armour Deck: 3,323 tons, 11.1 %
    - Conning Tower: 291 tons, 1.0 %
 Machinery: 1,438 tons, 4.8 %
 Hull, fittings & equipment: 13,594 tons, 45.3 %
 Fuel, ammunition & stores: 1,988 tons, 6.6 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   52,047 lbs / 23,608 Kg = 23.2 x 16.5 " / 419 mm shells or 10.0 torpedoes
 Stability (Unstable if below 1.00): 1.04
 Metacentric height 5.8 ft / 1.8 m
 Roll period: 18.4 seconds
 Steadiness - As gun platform (Average = 50 %): 91 %
   - Recoil effect (Restricted arc if above 1.00): 0.97
 Seaboat quality  (Average = 1.00): 1.82

Hull form characteristics:
 Hull has a flush deck
 Block coefficient: 0.538
 Length to Beam Ratio: 5.90 : 1
 'Natural speed' for length: 24.90 kts
 Power going to wave formation at top speed: 46 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 2.00 degrees
 Stern overhang: -2.00 ft / -0.61 m
 Freeboard (% = measuring location as a percentage of overall length):
    - Stem:  27.00 ft / 8.23 m
    - Forecastle (20 %): 25.00 ft / 7.62 m
    - Mid (50 %):  25.00 ft / 7.62 m
    - Quarterdeck (15 %): 25.00 ft / 7.62 m
    - Stern:  25.00 ft / 7.62 m
    - Average freeboard: 25.16 ft / 7.67 m
 Ship tends to be wet forward

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 74.9 %
  - Above water (accommodation/working, high = better): 187.8 %
 Waterplane Area: 44,910 Square feet or 4,172 Square metres
 Displacement factor (Displacement / loading): 105 %
 Structure weight / hull surface area: 213 lbs/sq ft or 1,042 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.90
  - Longitudinal: 2.53
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is excellent
 Room for accommodation and workspaces is excellent
 Ship has slow, easy roll, a good, steady gun platform
 Excellent seaboat, comfortable, can fire her guns in the heaviest weather