A further variant: the F/CA/1917 Mod.B

On the next page of the Red Book, the French fast cruiser is modified further with a heavier armament and lighter protection. The armament is 6-11in (35 ton) BLR and 8-6in QF (6 ton) guns. I followed the weights as closely as I could. The machinery is intended to be 30 SHP/ton and to have 191,400 SHP. The protection drops to only 1,207 tons, in the specification. I was not able to hit these numbers exactly, but I came close. By the time I adjusted the displacement to achieve an adequate strength and seakeeping, the SHP dropped, along with the machinery weight. This is the new Springsharp report:

F/CA/1917 Mod.A, France Heavy Cruiser laid down 1917 (Engine 1923)

Displacement:
 17,768 t light; 18,499 t standard; 19,900 t normal; 21,021 t full load

Dimensions: Length overall / water x beam x draught
 730.08 ft / 729.00 ft x 80.00 ft x 24.00 ft (normal load)
 222.53 m / 222.20 m x 24.38 m  x 7.32 m

Armament:
      6 - 11.00" / 279 mm guns (2x3 guns), 665.50lbs / 301.87kg shells, 1917 Model
   Breech loading guns in turrets (on barbettes)
   on centreline, all forward, 1 raised mount - superfiring
      8 - 6.00" / 152 mm guns in single mounts, 108.00lbs / 48.99kg shells, 1917 Model
   Quick firing guns in deck mounts with hoists
   on side, all aft
 Weight of broadside 4,857 lbs / 2,203 kg
 Shells per gun, main battery: 120
 6 - 21.0" / 533.4 mm above water torpedoes

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 3.00" / 76 mm 370.00 ft / 112.78 m 9.00 ft / 2.74 m
 Ends: Unarmoured
   Main Belt covers 78 % of normal length
   Main belt does not fully cover magazines and engineering spaces

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

   - Armour deck: 1.00" / 25 mm, Conning tower: 8.00" / 203 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 4 shafts, 176,586 shp / 131,733 Kw = 35.20 kts
 Range 6,500nm at 15.00 kts
 Bunker at max displacement = 2,521 tons

Complement:
 837 - 1,089

Cost:
 £3.560 million / $14.241 million

Distribution of weights at normal displacement:
 Armament: 607 tons, 3.1 %
 Armour: 2,292 tons, 11.5 %
    - Belts: 438 tons, 2.2 %
    - Torpedo bulkhead: 0 tons, 0.0 %
    - Armament: 1,010 tons, 5.1 %
    - Armour Deck: 717 tons, 3.6 %
    - Conning Tower: 127 tons, 0.6 %
 Machinery: 5,902 tons, 29.7 %
 Hull, fittings & equipment: 8,967 tons, 45.1 %
 Fuel, ammunition & stores: 2,132 tons, 10.7 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   18,002 lbs / 8,165 Kg = 27.1 x 11.0 " / 279 mm shells or 1.8 torpedoes
 Stability (Unstable if below 1.00): 1.19
 Metacentric height 4.9 ft / 1.5 m
 Roll period: 15.2 seconds
 Steadiness - As gun platform (Average = 50 %): 53 %
   - Recoil effect (Restricted arc if above 1.00): 0.53
 Seaboat quality  (Average = 1.00): 1.06

Hull form characteristics:
 Hull has rise forward of midbreak
 Block coefficient: 0.498
 Length to Beam Ratio: 9.11 : 1
 'Natural speed' for length: 27.00 kts
 Power going to wave formation at top speed: 57 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 2.00 degrees
 Stern overhang: 0.00 ft / 0.00 m
 Freeboard (% = measuring location as a percentage of overall length):
    - Stem:  31.00 ft / 9.45 m
    - Forecastle (20 %): 26.00 ft / 7.92 m
    - Mid (73 %):  26.00 ft / 7.92 m (18.00 ft / 5.49 m aft of break)
    - Quarterdeck (15 %): 18.00 ft / 5.49 m
    - Stern:  18.00 ft / 5.49 m
    - Average freeboard: 24.24 ft / 7.39 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 119.3 %
  - Above water (accommodation/working, high = better): 201.0 %
 Waterplane Area: 38,773 Square feet or 3,602 Square metres
 Displacement factor (Displacement / loading): 105 %
 Structure weight / hull surface area: 151 lbs/sq ft or 738 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.96
  - Longitudinal: 1.43
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is cramped
 Room for accommodation and workspaces is excellent