A "moderate dimensions" ship: GB/BB/1915 small

Many authorities, including Lord Brassey, were advocating battleships of "moderate dimensions" in the late 19th and early 20th Century. Back in the early 1970's, we had experimented with such a ship design to see what could be achieved. This version, which I just created, has my 17in/45 gun, which weighed 138.6 tons, and fired an AP shot of 2814 lbs at a velocity of 2,850 ft/sec. The original specification did not specify a gun caliber, but the guns were clearly large, as the barrels were quite long. The main armament is 6-17in/45 BLR and the secondary armament is 10-5.5in QF guns. The belt is only 10in. The design depends on having the lightest weight machinery allowed. This is the Springsharp report:

GB/BB/1915 Small, Great Britain Battleship laid down 1915 (Engine 1950)

Displacement:
 27,456 t light; 28,879 t standard; 30,134 t normal; 31,138 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
 (628.00 ft / 625.00 ft) x 100.00 ft x (25.00 / 25.72 ft)
 (191.41 m / 190.50 m) x 30.48 m  x (7.62 / 7.84 m)

Armament:
      6 - 17.00" / 432 mm 45.0 cal guns - 2,814.00lbs / 1,276.41kg shells, 80 per gun
   Breech loading guns in turret on barbette mounts, 1915 Model
   2 x Triple mounts on centreline, forward deck forward
  1 raised mount - superfiring
      10 - 5.50" / 140 mm 45.0 cal guns - 83.90lbs / 38.05kg shells, 150 per gun
   Quick firing guns in deck and hoist mounts, 1915 Model
   10 x Single mounts on sides, forward deck aft
  2 raised mounts - superfiring
      Weight of broadside 17,723 lbs / 8,039 kg

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 10.0" / 254 mm 320.00 ft / 97.54 m 16.00 ft / 4.88 m
 Ends: Unarmoured
   Main Belt covers 79 % of normal length

   - Torpedo Bulkhead:
  4.00" / 102 mm 320.00 ft / 97.54 m 24.40 ft / 7.44 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 12.0" / 305 mm 8.00" / 203 mm  12.0" / 305 mm

   - Armoured deck - multiple decks: 4.00" / 102 mm For and Aft decks
 Forecastle: 3.00" / 76 mm  Quarter deck: 4.00" / 102 mm

   - Conning towers: Forward 10.00" / 254 mm,  Aft 0.00" / 0 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 4 shafts, 70,682 shp / 52,729 Kw = 25.00 kts
 Range 5,400nm at 15.00 kts
 Bunker at max displacement = 2,259 tons

Complement:
 1,143 - 1,486

Cost:
 £3.873 million / $15.490 million

Distribution of weights at normal displacement:
 Armament: 2,579 tons, 8.6 %
 Armour: 9,652 tons, 32.0 %
    - Belts: 2,401 tons, 8.0 %
    - Torpedo bulkhead: 1,156 tons, 3.8 %
    - Armament: 2,344 tons, 7.8 %
    - Armour Deck: 3,542 tons, 11.8 %
    - Conning Tower: 209 tons, 0.7 %
 Machinery: 1,691 tons, 5.6 %
 Hull, fittings & equipment: 13,535 tons, 44.9 %
 Fuel, ammunition & stores: 2,678 tons, 8.9 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   55,000 lbs / 24,948 Kg = 22.4 x 17.0 " / 432 mm shells or 9.9 torpedoes
 Stability (Unstable if below 1.00): 1.18
 Metacentric height 6.8 ft / 2.1 m
 Roll period: 16.1 seconds
 Steadiness - As gun platform (Average = 50 %): 63 %
   - Recoil effect (Restricted arc if above 1.00): 0.94
 Seaboat quality  (Average = 1.00): 1.27

Hull form characteristics:
 Hull has rise forward of midbreak,
   a ram bow and a cruiser stern
 Block coefficient (normal/deep): 0.675 / 0.678
 Length to Beam Ratio: 6.25 : 1
 'Natural speed' for length: 25.00 kts
 Power going to wave formation at top speed: 52 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): -2.00 degrees
 Stern overhang: -1.00 ft / -0.30 m
 Freeboard (% = length of deck as a percentage of waterline length):
    Fore end,  Aft end
    - Forecastle: 25.00 %,  28.00 ft / 8.53 m,  26.00 ft / 7.92 m
    - Forward deck: 42.00 %,  26.00 ft / 7.92 m,  26.00 ft / 7.92 m
    - Aft deck: 18.00 %,  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:  23.56 ft / 7.18 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 77.9 %
  - Above water (accommodation/working, high = better): 192.6 %
 Waterplane Area: 48,982 Square feet or 4,551 Square metres
 Displacement factor (Displacement / loading): 112 %
 Structure weight / hull surface area: 219 lbs/sq ft or 1,068 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.92
  - Longitudinal: 2.04
  - 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