The short version of the F/CA/1917 fast belted cruiser

The short version of the F/CA/1917 fast belted cruiser is something of a failure. I had greatly overestimated what might be possible when I created the concept. I was going to build six of the ships for my building program, but I had ignored hull strength and seakeeping considerations. The ship had 8-9.4in guns in two quadruple turrets mounted forward and then had 8-4in QF guns aft. the narrow belt was 8in. The speed is much lower and the deck armour is much lighter than I had planned. I would expect that a 729ft version would work better. This is the Springsharp report:

F/CA/1917, France Armoured Cruiser laid down 1917 (Engine 1931)

Displacement:
 17,282 t light; 17,984 t standard; 18,952 t normal; 19,726 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
 (679.05 ft / 676.00 ft) x 75.00 ft x (21.00 / 21.72 ft)
 (206.97 m / 206.04 m) x 22.86 m  x (6.40 / 6.62 m)

Armament:
      8 - 9.40" / 239 mm 50.0 cal guns - 439.64lbs / 199.42kg shells, 150 per gun
   Breech loading guns in turret on barbette mounts, 1917 Model
   8 x Quad mounts on centreline, forward deck forward
  1 raised mount - superfiring
      8 - 4.00" / 102 mm 45.0 cal guns - 32.00lbs / 14.51kg shells, 150 per gun
   Quick firing guns in deck and hoist mounts, 1917 Model
   4 x Twin mounts on sides, aft deck forward
      Weight of broadside 3,773 lbs / 1,711 kg
      6 - 21.0" / 533 mm, 22.00 ft / 6.71 m torpedoes - 1.409 t each, 8.455 t total
 In 2 sets of deck mounted side rotating tubes

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 8.00" / 203 mm 340.00 ft / 103.63 m 8.00 ft / 2.44 m
 Ends: Unarmoured
   Main Belt covers 77 % of normal length
   Main belt does not fully cover magazines and engineering spaces

   - Torpedo Bulkhead:
  1.00" / 25 mm 340.00 ft / 103.63 m 20.00 ft / 6.10 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 8.00" / 203 mm 5.00" / 127 mm  8.00" / 203 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, 145,427 shp / 108,488 Kw = 33.00 kts
 Range 4,800nm at 15.00 kts
 Bunker at max displacement = 1,742 tons

Complement:
 806 - 1,049

Cost:
 £2.917 million / $11.668 million

Distribution of weights at normal displacement:
 Armament: 936 tons, 4.9 %
    - Guns: 927 tons, 4.9 %
    - Torpedoes: 8 tons, 0.0 %
 Armour: 4,839 tons, 25.5 %
    - Belts: 954 tons, 5.0 %
    - Torpedo bulkhead: 252 tons, 1.3 %
    - Armament: 1,394 tons, 7.4 %
    - Armour Deck: 2,117 tons, 11.2 %
    - Conning Tower: 123 tons, 0.6 %
 Machinery: 4,349 tons, 22.9 %
 Hull, fittings & equipment: 7,158 tons, 37.8 %
 Fuel, ammunition & stores: 1,670 tons, 8.8 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   27,075 lbs / 12,281 Kg = 65.2 x 9.4 " / 239 mm shells or 3.1 torpedoes
 Stability (Unstable if below 1.00): 1.10
 Metacentric height 3.9 ft / 1.2 m
 Roll period: 16.0 seconds
 Steadiness - As gun platform (Average = 50 %): 51 %
   - Recoil effect (Restricted arc if above 1.00): 0.60
 Seaboat quality  (Average = 1.00): 1.01

Hull form characteristics:
 Hull has low quarterdeck ,
   an extended bulbous bow and a cruiser stern
 Block coefficient (normal/deep): 0.623 / 0.627
 Length to Beam Ratio: 9.01 : 1
 'Natural speed' for length: 26.00 kts
 Power going to wave formation at top speed: 59 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 6.00 degrees
 Stern overhang: -2.00 ft / -0.61 m
 Freeboard (% = length of deck as a percentage of waterline length):
    Fore end,  Aft end
    - Forecastle: 20.00 %,  29.00 ft / 8.84 m,  28.00 ft / 8.53 m
    - Forward deck: 30.00 %,  28.00 ft / 8.53 m,  27.00 ft / 8.23 m
    - Aft deck: 23.00 %,  27.00 ft / 8.23 m,  27.00 ft / 8.23 m
    - Quarter deck: 27.00 %,  19.00 ft / 5.79 m,  19.00 ft / 5.79 m
    - Average freeboard:  25.27 ft / 7.70 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 128.0 %
  - Above water (accommodation/working, high = better): 241.2 %
 Waterplane Area: 37,884 Square feet or 3,520 Square metres
 Displacement factor (Displacement / loading): 110 %
 Structure weight / hull surface area: 133 lbs/sq ft or 650 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.97
  - Longitudinal: 1.32
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is cramped
 Room for accommodation and workspaces is excellent