The F/BB/1937 design HAD to have 18in guns

I felt like any ship laid down in 1937 that didn't need to follow restrictive treaties needed 18in guns. The F/BB/1937 has eight in two quadruple turrets mounted forward. The armour basis was increased to 15in, the deck to 8in, and the speed to 31 knots. The speed increase was costly, as achieving adequate seakeeping involved increasing freeboard and length. The need for hull strength ballooned the displacement, making achieving the minimum acceptable seakeeping that much more difficult. This is the Springsharp report:

F/BB/1937, France Battleship laid down 1937

Displacement:
 60,805 t light; 63,293 t standard; 66,700 t normal; 69,426 t full load

Dimensions: Length overall / water x beam x draught
 862.80 ft / 857.00 ft x 118.00 ft x 34.00 ft (normal load)
 262.98 m / 261.21 m x 35.97 m  x 10.36 m

Armament:
      8 - 18.00" / 457 mm guns (2x4 guns), 2,916.00lbs / 1,322.68kg shells, 1937 Model
   Breech loading guns in turrets (on barbettes)
   on centreline, all forward, 1 raised mount - superfiring
      18 - 5.51" / 140 mm guns (6x3 guns), 83.72lbs / 37.98kg shells, 1937 Model
   Quick firing guns in turrets (on barbettes)
   on side, all amidships, all raised mounts - superfiring
      16 - 3.94" / 100 mm guns (8x2 guns), 30.51lbs / 13.84kg shells, 1937 Model
   Anti-aircraft guns in deck mounts with hoists
   on side, all amidships, all raised mounts - superfiring
      48 - 1.85" / 47.0 mm guns (24x2 guns), 3.17lbs / 1.44kg shells, 1937 Model
   Anti-aircraft guns in deck mounts 
   on side, evenly spread, 18 raised mounts
 Weight of broadside 25,475 lbs / 11,555 kg
 Shells per gun, main battery: 80

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 15.0" / 381 mm 570.00 ft / 173.74 m 16.00 ft / 4.88 m
 Ends: 5.00" / 127 mm 241.00 ft / 73.46 m 12.00 ft / 3.66 m
   46.00 ft / 14.02 m Unarmoured ends
   Main Belt covers 102 % of normal length

   - Torpedo Bulkhead:
  4.00" / 102 mm 570.00 ft / 173.74 m 30.00 ft / 9.14 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 15.0" / 381 mm 12.0" / 305 mm  15.0" / 381 mm
 2nd: 5.00" / 127 mm 5.00" / 127 mm  5.00" / 127 mm

   - Armour deck: 8.00" / 203 mm, Conning tower: 15.00" / 381 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 4 shafts, 234,595 shp / 175,008 Kw = 31.00 kts
 Range 8,500nm at 15.00 kts
 Bunker at max displacement = 6,133 tons

Complement:
 2,074 - 2,697

Cost:
 £31.164 million / $124.656 million

Distribution of weights at normal displacement:
 Armament: 3,184 tons, 4.8 %
 Armour: 25,847 tons, 38.8 %
    - Belts: 6,436 tons, 9.6 %
    - Torpedo bulkhead: 2,531 tons, 3.8 %
    - Armament: 4,577 tons, 6.9 %
    - Armour Deck: 11,772 tons, 17.6 %
    - Conning Tower: 532 tons, 0.8 %
 Machinery: 6,502 tons, 9.7 %
 Hull, fittings & equipment: 25,272 tons, 37.9 %
 Fuel, ammunition & stores: 5,895 tons, 8.8 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   98,262 lbs / 44,571 Kg = 33.7 x 18.0 " / 457 mm shells or 16.5 torpedoes
 Stability (Unstable if below 1.00): 1.13
 Metacentric height 8.0 ft / 2.4 m
 Roll period: 17.5 seconds
 Steadiness - As gun platform (Average = 50 %): 52 %
   - Recoil effect (Restricted arc if above 1.00): 0.65
 Seaboat quality  (Average = 1.00): 1.04

Hull form characteristics:
 Hull has rise forward of midbreak
 Block coefficient: 0.679
 Length to Beam Ratio: 7.26 : 1
 'Natural speed' for length: 29.27 kts
 Power going to wave formation at top speed: 55 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 5.00 degrees
 Stern overhang: 3.00 ft / 0.91 m
 Freeboard (% = measuring location as a percentage of overall length):
    - Stem:  32.00 ft / 9.75 m
    - Forecastle (20 %): 28.00 ft / 8.53 m
    - Mid (67 %):  28.00 ft / 8.53 m (20.00 ft / 6.10 m aft of break)
    - Quarterdeck (15 %): 20.00 ft / 6.10 m
    - Stern:  20.00 ft / 6.10 m
    - Average freeboard: 25.68 ft / 7.83 m
 Ship tends to be wet forward

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 81.4 %
  - Above water (accommodation/working, high = better): 188.4 %
 Waterplane Area: 79,538 Square feet or 7,389 Square metres
 Displacement factor (Displacement / loading): 104 %
 Structure weight / hull surface area: 234 lbs/sq ft or 1,143 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.97
  - Longitudinal: 1.30
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is excellent
 Room for accommodation and workspaces is excellent