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Wednesday, April 05, 2006

The F/CA/1937 design

The F/CA/1937 design is a modest improvement over its predecessor. I was only able to achieve a 1/2 knot speed increase (to 33.5 knots) and added more 10cm AA guns to bring to the total to 16, now correctly categorized as "mount and hoist". The freeboard was increased by a foot to improve the seakeeping, and the displacement needed to rise to achieve adequate strength. This is the Springsharp report:
F/CA/1937, France Cruiser laid down 1937 (Engine 1942)

Displacement:
 14,834 t light; 15,453 t standard; 16,500 t normal; 17,338 t full load

Dimensions: Length overall / water x beam x draught
 671.80 ft / 667.00 ft x 66.00 ft x 23.00 ft (normal load)
 204.76 m / 203.30 m x 20.12 m  x 7.01 m

Armament:
      9 - 9.45" / 240 mm guns (3x3 guns), 421.80lbs / 191.32kg shells, 1937 Model
   Breech loading guns in turrets (on barbettes)
   on centreline ends, majority forward, 1 raised mount - superfiring
   Main guns limited to end-on fire
      8 - 5.12" / 130 mm guns (4x2 guns), 67.03lbs / 30.41kg shells, 1937 Model
   Dual purpose guns in deck mounts with hoists
   on side, all amidships
      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
      32 - 1.85" / 47.0 mm guns (16x2 guns), 3.17lbs / 1.44kg shells, 1937 Model
   Anti-aircraft guns in deck mounts 
   on side, evenly spread, 12 raised mounts
 Weight of broadside 4,922 lbs / 2,233 kg
 Shells per gun, main battery: 100
 8 - 21.7" / 549.9999 mm above water torpedoes

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 4.00" / 102 mm 460.00 ft / 140.21 m 16.00 ft / 4.88 m
 Ends: Unarmoured
   Main Belt covers 106 % of normal length
   Main belt does not fully cover magazines and engineering spaces

   - Torpedo Bulkhead:
  1.00" / 25 mm 460.00 ft / 140.21 m 22.00 ft / 6.71 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 4.00" / 102 mm 3.00" / 76 mm  4.00" / 102 mm
 2nd: 2.00" / 51 mm 2.00" / 51 mm  2.00" / 51 mm

   - Armour deck: 2.50" / 64 mm, Conning tower: 4.00" / 102 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 4 shafts, 135,902 shp / 101,383 Kw = 33.50 kts
 Range 6,500nm at 15.00 kts
 Bunker at max displacement = 1,885 tons

Complement:
 727 - 946

Cost:
 £8.362 million / $33.448 million

Distribution of weights at normal displacement:
 Armament: 615 tons, 3.7 %
 Armour: 3,695 tons, 22.4 %
    - Belts: 1,217 tons, 7.4 %
    - Torpedo bulkhead: 374 tons, 2.3 %
    - Armament: 600 tons, 3.6 %
    - Armour Deck: 1,448 tons, 8.8 %
    - Conning Tower: 56 tons, 0.3 %
 Machinery: 3,550 tons, 21.5 %
 Hull, fittings & equipment: 6,973 tons, 42.3 %
 Fuel, ammunition & stores: 1,666 tons, 10.1 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   20,207 lbs / 9,166 Kg = 47.9 x 9.4 " / 240 mm shells or 2.5 torpedoes
 Stability (Unstable if below 1.00): 1.10
 Metacentric height 3.2 ft / 1.0 m
 Roll period: 15.5 seconds
 Steadiness - As gun platform (Average = 50 %): 55 %
   - Recoil effect (Restricted arc if above 1.00): 1.04
 Seaboat quality  (Average = 1.00): 1.10

Hull form characteristics:
 Hull has rise forward of midbreak
 Block coefficient: 0.570
 Length to Beam Ratio: 10.11 : 1
 'Natural speed' for length: 25.83 kts
 Power going to wave formation at top speed: 58 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 5.00 degrees
 Stern overhang: 2.00 ft / 0.61 m
 Freeboard (% = measuring location as a percentage of overall length):
    - Stem:  32.00 ft / 9.75 m
    - Forecastle (20 %): 26.00 ft / 7.92 m
    - Mid (67 %):  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: 23.84 ft / 7.27 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 140.7 %
  - Above water (accommodation/working, high = better): 169.2 %
 Waterplane Area: 31,315 Square feet or 2,909 Square metres
 Displacement factor (Displacement / loading): 105 %
 Structure weight / hull surface area: 134 lbs/sq ft or 652 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.96
  - Longitudinal: 1.54
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is cramped
 Room for accommodation and workspaces is excellent

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