I am amazed at how accurate the 1971 concept for the Ger/BB/1915 design

The original specification for the Ger/BB/1915 design is pretty expansive, and has the extreme draft specified of 40 ft. I followed that specification as closely as possible, in terms of power and weights, except that I slightly reduced the draft. The power specified was 120,000 SHP, and that actually produces slightly more than 25 knots, not just the 20 knots envisioned, so that is good. The protection weight is so great that I had great difficulty in increasing the protection to that amount. The protection is really extreme, as 38,070 tons was specified on a 72,000 tons standard ship. This is the Springsharp report:

Ger/BB/1915, Germany Battleship laid down 1915 (Engine 1937)

Displacement:
 69,130 t light; 72,038 t standard; 75,300 t normal; 77,909 t full load

Dimensions: Length overall / water x beam x draught
 751.57 ft / 750.00 ft x 130.00 ft x 39.00 ft (normal load)
 229.08 m / 228.60 m x 39.62 m  x 11.89 m

Armament:
      9 - 18.00" / 457 mm guns (3 mounts), 2,916.00lbs / 1,322.68kg shells, 1915 Model
   Breech loading guns in turrets (on barbettes)
   on centreline ends, majority forward, 2 raised guns - superfiring
      24 - 5.00" / 127 mm guns (12x2 guns), 62.50lbs / 28.35kg shells, 1915 Model
   Quick firing guns in turrets (on barbettes)
   on side, all amidships, 4 raised mounts - superfiring
 Weight of broadside 27,744 lbs / 12,584 kg
 Shells per gun, main battery: 90

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 22.0" / 559 mm 400.00 ft / 121.92 m 23.00 ft / 7.01 m
 Ends: Unarmoured
   Main Belt covers 82 % of normal length

   - Torpedo Bulkhead:
  10.0" / 254 mm 400.00 ft / 121.92 m 39.00 ft / 11.89 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 22.0" / 559 mm 14.0" / 356 mm  22.0" / 559 mm
 2nd: 5.00" / 127 mm 5.00" / 127 mm  5.00" / 127 mm

   - Armour deck: 10.00" / 254 mm, Conning tower: 22.00" / 559 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 2 shafts, 120,277 shp / 89,727 Kw = 25.20 kts
 Range 7,500nm at 15.00 kts
 Bunker at max displacement = 5,871 tons

Complement:
 2,272 - 2,954

Cost:
 £8.435 million / $33.742 million

Distribution of weights at normal displacement:
 Armament: 3,468 tons, 4.6 %
 Armour: 37,997 tons, 50.5 %
    - Belts: 9,500 tons, 12.6 %
    - Torpedo bulkhead: 5,772 tons, 7.7 %
    - Armament: 7,511 tons, 10.0 %
    - Armour Deck: 14,368 tons, 19.1 %
    - Conning Tower: 845 tons, 1.1 %
 Machinery: 3,334 tons, 4.4 %
 Hull, fittings & equipment: 24,182 tons, 32.1 %
 Fuel, ammunition & stores: 6,170 tons, 8.2 %
 Miscellaneous weights: 150 tons, 0.2 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   138,171 lbs / 62,673 Kg = 47.4 x 18.0 " / 457 mm shells or 37.4 torpedoes
 Stability (Unstable if below 1.00): 1.11
 Metacentric height 9.0 ft / 2.7 m
 Roll period: 18.2 seconds
 Steadiness - As gun platform (Average = 50 %): 69 %
   - Recoil effect (Restricted arc if above 1.00): 0.52
 Seaboat quality  (Average = 1.00): 1.38

Hull form characteristics:
 Hull has a flush deck
 Block coefficient: 0.693
 Length to Beam Ratio: 5.77 : 1
 'Natural speed' for length: 27.39 kts
 Power going to wave formation at top speed: 51 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 3.00 degrees
 Stern overhang: 0.00 ft / 0.00 m
 Freeboard (% = measuring location as a percentage of overall length):
    - Stem:  30.00 ft / 9.14 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: 25.40 ft / 7.74 m
 Ship tends to be wet forward

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 58.9 %
  - Above water (accommodation/working, high = better): 162.8 %
 Waterplane Area: 77,667 Square feet or 7,216 Square metres
 Displacement factor (Displacement / loading): 104 %
 Structure weight / hull surface area: 232 lbs/sq ft or 1,135 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.95
  - Longitudinal: 1.68
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is excellent
 Room for accommodation and workspaces is excellent
 Good seaboat, rides out heavy weather easily