The 35 knot version of the GB/CB/1915 design study

The GB/CB/1915 design study uses an imaginery 15in/45 guns and has a 35 knot speed specified. What makes that especially difficult is that the draft is shallow at 25.9ft. The specification was very over-optimistic:

Length: 850ft     Light displacement: 35,000 tons   Normal:  36,500 tons
Beam:   105ft     Full load: 39,000 tons
Depth:   45ft     Cp: 0.57  Cm: 0.97
Draft:   25.9ft
8-15in/45 guns    Speed: 35 knots   154,000 SHP  184,500 SHP max.

This is the Springsharp report for the version that does whatever it takes to reach 35 knots:

GB/CB/1915 design study, Great Britain Battlecruiser laid down 1915 (Engine 1950)

Displacement:
 38,888 t light; 40,649 t standard; 43,392 t normal; 45,586 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
 (855.48 ft / 850.00 ft) x 105.00 ft x (25.90 / 27.02 ft)
 (260.75 m / 259.08 m) x 32.00 m  x (7.89 / 8.23 m)

Armament:
      8 - 15.00" / 381 mm 45.0 cal guns - 1,950.00lbs / 884.51kg shells, 90 per gun
   Breech loading guns in turret on barbette mounts, 1915 Model
   4 x Twin mounts on centreline ends, evenly spread
  2 raised mounts - superfiring
      16 - 5.50" / 140 mm 45.0 cal guns - 85.00lbs / 38.56kg shells, 150 per gun
   Quick firing guns in deck and hoist mounts, 1915 Model
   16 x Single mounts on sides, evenly spread
  4 raised mounts
      Weight of broadside 16,960 lbs / 7,693 kg

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 8.00" / 203 mm 565.00 ft / 172.21 m 9.00 ft / 2.74 m
 Ends: Unarmoured
 Upper: 5.00" / 127 mm 565.00 ft / 172.21 m 9.00 ft / 2.74 m
   Main Belt covers 102 % of normal length

   - Torpedo Bulkhead:
  2.00" / 51 mm 565.00 ft / 172.21 m 25.90 ft / 7.89 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 3.00" / 76 mm  4.00" / 102 mm

   - Protected 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, 290,772 shp / 216,916 Kw = 35.00 kts
 Range 6,500nm at 18.00 kts
 Bunker at max displacement = 4,937 tons

Complement:
 1,503 - 1,954

Cost:
 £5.428 million / $21.711 million

Distribution of weights at normal displacement:
 Armament: 2,618 tons, 6.0 %
 Armour: 10,572 tons, 24.4 %
    - Belts: 2,799 tons, 6.4 %
    - Torpedo bulkhead: 1,083 tons, 2.5 %
    - Armament: 2,631 tons, 6.1 %
    - Armour Deck: 3,846 tons, 8.9 %
    - Conning Tower: 213 tons, 0.5 %
 Machinery: 6,956 tons, 16.0 %
 Hull, fittings & equipment: 18,741 tons, 43.2 %
 Fuel, ammunition & stores: 4,504 tons, 10.4 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   68,819 lbs / 31,216 Kg = 40.8 x 15.0 " / 381 mm shells or 8.8 torpedoes
 Stability (Unstable if below 1.00): 1.15
 Metacentric height 7.0 ft / 2.1 m
 Roll period: 16.7 seconds
 Steadiness - As gun platform (Average = 50 %): 51 %
   - Recoil effect (Restricted arc if above 1.00): 0.82
 Seaboat quality  (Average = 1.00): 1.03

Hull form characteristics:
 Hull has rise forward of midbreak,
   a normal bow and a cruiser stern
 Block coefficient (normal/deep): 0.657 / 0.662
 Length to Beam Ratio: 8.10 : 1
 'Natural speed' for length: 29.15 kts
 Power going to wave formation at top speed: 58 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 8.00 degrees
 Stern overhang: -3.00 ft / -0.91 m
 Freeboard (% = length of deck as a percentage of waterline length):
    Fore end,  Aft end
    - Forecastle: 34.00 %,  39.00 ft / 11.89 m,  34.00 ft / 10.36 m
    - Forward deck: 33.00 %,  34.00 ft / 10.36 m,  34.00 ft / 10.36 m
    - Aft deck: 18.00 %,  26.00 ft / 7.92 m,  26.00 ft / 7.92 m
    - Quarter deck: 15.00 %,  26.00 ft / 7.92 m,  28.00 ft / 8.53 m
    - Average freeboard:  32.19 ft / 9.81 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 100.8 %
  - Above water (accommodation/working, high = better): 271.9 %
 Waterplane Area: 68,810 Square feet or 6,393 Square metres
 Displacement factor (Displacement / loading): 115 %
 Structure weight / hull surface area: 201 lbs/sq ft or 981 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.96
  - Longitudinal: 1.44
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is adequate
 Room for accommodation and workspaces is excellent