The GB/CB/1915 from the Blue Book

The specification of the first ship in the "Blue Book" from the early 1970's is quite simple and agressive:

38 Knots  850ft x 95ft
V/sqrt(L) = 1.3  Displacement=29,000 tons  180,000 SHP
4-13.5in guns    sqrt(L)=29.155
V/sqrt(L)= 1.303389247
7.215 SHP/ton  SHP required=209,235.1
calculation 18 July 1973

The Springsharp design is feasible only using the lightest allowed machinery and higher power:

GB/CB/1915 Fast (Red Book), Great Britain Battlecruiser laid down 1915 (Engine 1950)

Displacement:
 27,234 t light; 28,109 t standard; 28,966 t normal; 29,652 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
 (855.86 ft / 850.00 ft) x 95.00 ft x (31.00 / 31.48 ft)
 (260.87 m / 259.08 m) x 28.96 m  x (9.45 / 9.60 m)

Armament:
      4 - 13.50" / 343 mm 45.0 cal guns - 1,350.00lbs / 612.35kg shells, 90 per gun
   Breech loading guns in turret on barbette mounts, 1915 Model
   2 x Twin mounts on centreline ends, evenly spread
      12 - 4.00" / 102 mm 45.0 cal guns - 32.00lbs / 14.51kg shells, 120 per gun
   Breech loading guns in deck and hoist mount, 1915 Model
   1 x Single mount on sides, forward deck aft
      Weight of broadside 5,784 lbs / 2,624 kg

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 5.00" / 127 mm 490.00 ft / 149.35 m 17.00 ft / 5.18 m
 Ends: Unarmoured
   Main Belt covers 89 % of normal length
   Main belt does not fully cover magazines and engineering spaces

   - Torpedo Bulkhead:
  1.50" / 38 mm 490.00 ft / 149.35 m 31.00 ft / 9.45 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 8.00" / 203 mm 5.00" / 127 mm  8.00" / 203 mm
 2nd: 4.00" / 102 mm 2.00" / 51 mm  4.00" / 102 mm

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

   - Conning towers: Forward 8.00" / 203 mm,  Aft 0.00" / 0 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 4 shafts, 271,924 shp / 202,855 Kw = 38.00 kts
 Range 4,200nm at 14.00 kts
 Bunker at max displacement = 1,542 tons

Complement:
 1,109 - 1,443

Cost:
 £3.439 million / $13.756 million

Distribution of weights at normal displacement:
 Armament: 959 tons, 3.3 %
 Armour: 6,515 tons, 22.5 %
    - Belts: 1,756 tons, 6.1 %
    - Torpedo bulkhead: 843 tons, 2.9 %
    - Armament: 968 tons, 3.3 %
    - Armour Deck: 2,785 tons, 9.6 %
    - Conning Tower: 163 tons, 0.6 %
 Machinery: 6,505 tons, 22.5 %
 Hull, fittings & equipment: 13,255 tons, 45.8 %
 Fuel, ammunition & stores: 1,732 tons, 6.0 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   45,842 lbs / 20,794 Kg = 37.3 x 13.5 " / 343 mm shells or 5.5 torpedoes
 Stability (Unstable if below 1.00): 1.17
 Metacentric height 6.2 ft / 1.9 m
 Roll period: 16.0 seconds
 Steadiness - As gun platform (Average = 50 %): 68 %
   - Recoil effect (Restricted arc if above 1.00): 0.44
 Seaboat quality  (Average = 1.00): 1.36

Hull form characteristics:
 Hull has low quarterdeck ,
   an extended bulbous bow and a cruiser stern
 Block coefficient (normal/deep): 0.405 / 0.408
 Length to Beam Ratio: 8.95 : 1
 'Natural speed' for length: 29.15 kts
 Power going to wave formation at top speed: 54 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 9.00 degrees
 Stern overhang: 0.00 ft / 0.00 m
 Freeboard (% = length of deck as a percentage of waterline length):
    Fore end,  Aft end
    - Forecastle: 20.00 %,  37.00 ft / 11.28 m,  34.00 ft / 10.36 m
    - Forward deck: 30.00 %,  34.00 ft / 10.36 m,  32.00 ft / 9.75 m
    - Aft deck: 19.00 %,  32.00 ft / 9.75 m,  32.00 ft / 9.75 m
    - Quarter deck: 31.00 %,  24.00 ft / 7.32 m,  24.00 ft / 7.32 m
    - Average freeboard:  30.46 ft / 9.28 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 112.6 %
  - Above water (accommodation/working, high = better): 279.2 %
 Waterplane Area: 49,852 Square feet or 4,631 Square metres
 Displacement factor (Displacement / loading): 119 %
 Structure weight / hull surface area: 170 lbs/sq ft or 831 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.93
  - Longitudinal: 1.86
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is cramped
 Room for accommodation and workspaces is excellent
 Good seaboat, rides out heavy weather easily