Forty knots and 4-17in guns

I wanted to see if the GB/CB/1921 Super Fast design could be extended to reach 40 knots. I was successful, by increasing the dimensions and displacement. I also took the liberty of replacing the 4in QF guns with the more substantial 5in guns. The result is a ship that can outrun smaller ships in a seaway, even if they somehow were nominally faster. Light weight machinery is essential, of course. I was able to coerce 39.6 SHP/ton from Springsharp. This is not unreasonable for a ship laid down in 1921, as much earlier ships had achieved 50 to 60 SHP/ton. Of course, the power output is very great. It could only fit into the ship if it is higher power output for size and weight. The armour plan is unchanged but the armament is now 4-17in BLR and 12-5in QF guns. The roll period is very good at 15.6 seconds. This is the Springsharp report:

GB/CB/1921 Super Fast Mod.A  Red Book, Great Britain Battlecruiser laid down 1921 (Engine 1945)

Displacement:
 32,693 t light; 33,885 t standard; 35,800 t normal; 37,332 t full load

Dimensions: Length overall / water x beam x draught
 881.66 ft / 879.00 ft x 94.00 ft x 31.00 ft (normal load)
 268.73 m / 267.92 m x 28.65 m  x 9.45 m

Armament:
      4 - 17.00" / 432 mm guns (2x2 guns), 2,456.50lbs / 1,114.25kg shells, 1921 Model
   Breech loading guns in turrets (on barbettes)
   on centreline ends, evenly spread
      12 - 5.00" / 127 mm guns in single mounts, 62.50lbs / 28.35kg shells, 1921 Model
   Quick firing guns in deck mounts with hoists
   on centreline ends, evenly spread
 Weight of broadside 10,576 lbs / 4,797 kg
 Shells per gun, main battery: 80

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 6.00" / 152 mm 520.00 ft / 158.50 m 12.00 ft / 3.66 m
 Ends: Unarmoured
   Main Belt covers 91 % of normal length
   Main belt does not fully cover magazines and engineering spaces

   - Torpedo Bulkhead:
  1.00" / 25 mm 520.00 ft / 158.50 m 29.00 ft / 8.84 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 6.00" / 152 mm 4.00" / 102 mm  6.00" / 152 mm
 2nd: 3.00" / 76 mm 3.00" / 76 mm  3.00" / 76 mm

   - Armour deck: 2.00" / 51 mm, Conning tower: 6.00" / 152 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 6 shafts, 390,931 shp / 291,635 Kw = 40.00 kts
 Range 7,500nm at 15.00 kts
 Bunker at max displacement = 3,446 tons

Complement:
 1,300 - 1,691

Cost:
 £9.257 million / $37.029 million

Distribution of weights at normal displacement:
 Armament: 1,322 tons, 3.7 %
 Armour: 5,435 tons, 15.2 %
    - Belts: 1,591 tons, 4.4 %
    - Torpedo bulkhead: 558 tons, 1.6 %
    - Armament: 1,128 tons, 3.2 %
    - Armour Deck: 2,017 tons, 5.6 %
    - Conning Tower: 140 tons, 0.4 %
 Machinery: 9,872 tons, 27.6 %
 Hull, fittings & equipment: 16,064 tons, 44.9 %
 Fuel, ammunition & stores: 3,107 tons, 8.7 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   32,840 lbs / 14,896 Kg = 13.4 x 17.0 " / 432 mm shells or 3.4 torpedoes
 Stability (Unstable if below 1.00): 1.20
 Metacentric height 6.4 ft / 1.9 m
 Roll period: 15.6 seconds
 Steadiness - As gun platform (Average = 50 %): 52 %
   - Recoil effect (Restricted arc if above 1.00): 0.60
 Seaboat quality  (Average = 1.00): 1.03

Hull form characteristics:
 Hull has rise forward of midbreak
 Block coefficient: 0.489
 Length to Beam Ratio: 9.35 : 1
 'Natural speed' for length: 29.65 kts
 Power going to wave formation at top speed: 59 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 4.00 degrees
 Stern overhang: -1.00 ft / -0.30 m
 Freeboard (% = measuring location as a percentage of overall length):
    - Stem:  38.00 ft / 11.58 m
    - Forecastle (20 %): 35.00 ft / 10.67 m
    - Mid (40 %):  35.00 ft / 10.67 m (27.00 ft / 8.23 m aft of break)
    - Quarterdeck (15 %): 27.00 ft / 8.23 m
    - Stern:  27.00 ft / 8.23 m
    - Average freeboard: 30.44 ft / 9.28 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 148.2 %
  - Above water (accommodation/working, high = better): 235.3 %
 Waterplane Area: 54,516 Square feet or 5,065 Square metres
 Displacement factor (Displacement / loading): 100 %
 Structure weight / hull surface area: 185 lbs/sq ft or 902 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.96
  - Longitudinal: 1.55
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is cramped
 Room for accommodation and workspaces is excellent