An American fast armoured cruiser: the US/CA/1915

I thought that an American fast armoured cruiser, laid down in 1915 might be an interesting design study. Since the ship is American, the main armament would need to be 8in guns, probably in triple turrets. Since the ship is an armoured cruiser, the armour basis needed to be at least 6 inches. The speed is a rather modest 30 knots, but that is adequate for this date. The ships built to this design would function as third class battleships on distant stations. This is the Springsharp report:

US/CA/1915, United States Armoured Cruiser laid down 1915

Displacement:
 13,862 t light; 14,452 t standard; 15,730 t normal; 16,752 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
 (660.91 ft / 650.00 ft) x 70.00 ft x (22.00 / 23.13 ft)
 (201.45 m / 198.12 m) x 21.34 m  x (6.71 / 7.05 m)

Armament:
      12 - 8.00" / 203 mm 55.0 cal guns - 275.00lbs / 124.74kg shells, 120 per gun
   Breech loading guns in turret on barbette mounts, 1915 Model
   4 x Triple mounts on centreline ends, evenly spread
  2 raised mounts - superfiring
      8 - 5.00" / 127 mm 51.0 cal guns - 65.00lbs / 29.48kg shells, 150 per gun
   Quick firing guns in deck and hoist mounts, 1915 Model
   8 x Single mounts on sides, forward deck aft
      4 - 3.00" / 76.2 mm 45.0 cal guns - 13.62lbs / 6.18kg shells, 150 per gun
   Anti-air guns in deck mounts, 1915 Model
   4 x Single mounts on sides, aft deck forward
      Weight of broadside 3,874 lbs / 1,757 kg
      6 - 21.0" / 533 mm, 20.00 ft / 6.10 m torpedoes - 1.283 t each, 7.697 t total
 In 2 sets of deck mounted side rotating tubes

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 6.00" / 152 mm 430.00 ft / 131.06 m 16.00 ft / 4.88 m
 Ends: Unarmoured
   Main Belt covers 102 % of normal length
   Main belt does not fully cover magazines and engineering spaces

   - Torpedo Bulkhead:
  1.00" / 25 mm 430.00 ft / 131.06 m 22.00 ft / 6.71 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 6.00" / 152 mm 3.00" / 76 mm  6.00" / 152 mm
 2nd: 2.00" / 51 mm 1.00" / 25 mm  2.00" / 51 mm

   - Armoured deck - multiple decks: 2.00" / 51 mm For and Aft decks

   - Conning towers: Forward 6.00" / 152 mm,  Aft 0.00" / 0 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 4 shafts, 85,892 shp / 64,076 Kw = 30.00 kts
 Range 6,500nm at 14.00 kts
 Bunker at max displacement = 2,301 tons

Complement:
 701 - 912

Cost:
 £2.009 million / $8.034 million

Distribution of weights at normal displacement:
 Armament: 1,089 tons, 6.9 %
    - Guns: 1,082 tons, 6.9 %
    - Torpedoes: 8 tons, 0.0 %
 Armour: 3,933 tons, 25.0 %
    - Belts: 1,707 tons, 10.8 %
    - Torpedo bulkhead: 350 tons, 2.2 %
    - Armament: 815 tons, 5.2 %
    - Armour Deck: 980 tons, 6.2 %
    - Conning Tower: 81 tons, 0.5 %
 Machinery: 3,253 tons, 20.7 %
 Hull, fittings & equipment: 5,586 tons, 35.5 %
 Fuel, ammunition & stores: 1,868 tons, 11.9 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   19,242 lbs / 8,728 Kg = 75.2 x 8.0 " / 203 mm shells or 2.7 torpedoes
 Stability (Unstable if below 1.00): 1.12
 Metacentric height 3.6 ft / 1.1 m
 Roll period: 15.5 seconds
 Steadiness - As gun platform (Average = 50 %): 57 %
   - Recoil effect (Restricted arc if above 1.00): 0.61
 Seaboat quality  (Average = 1.00): 1.14

Hull form characteristics:
 Hull has rise forward of midbreak,
   an extended bulbous bow and a cruiser stern
 Block coefficient (normal/deep): 0.550 / 0.557
 Length to Beam Ratio: 9.29 : 1
 'Natural speed' for length: 25.50 kts
 Power going to wave formation at top speed: 53 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 22.00 degrees
 Stern overhang: -2.00 ft / -0.61 m
 Freeboard (% = length of deck as a percentage of waterline length):
    Fore end,  Aft end
    - Forecastle: 18.00 %,  27.00 ft / 8.23 m,  26.00 ft / 7.92 m
    - Forward deck: 17.00 %,  26.00 ft / 7.92 m,  26.00 ft / 7.92 m
    - Aft deck: 50.00 %,  18.00 ft / 5.49 m,  18.00 ft / 5.49 m
    - Quarter deck: 15.00 %,  18.00 ft / 5.49 m,  18.00 ft / 5.49 m
    - Average freeboard:  20.87 ft / 6.36 m
 Ship tends to be wet forward

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 129.7 %
  - Above water (accommodation/working, high = better): 170.6 %
 Waterplane Area: 31,754 Square feet or 2,950 Square metres
 Displacement factor (Displacement / loading): 107 %
 Structure weight / hull surface area: 127 lbs/sq ft or 621 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.98
  - Longitudinal: 1.12
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is cramped
 Room for accommodation and workspaces is excellent