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Wednesday, March 22, 2006

The F/BB/1923 design

The main improvements in the F/BB/1923 design are the 29 knot speed and the main armament now being 9-16.5in guns in triple turrets. The freeboard is a foot higher, and this ship is not wet forward. The protection against gunfire seems adequate, while the underwater protection is above-average (if it will take 11 torpedoes, that is how I would rate the design). The AA armament is sub-standard, but in 1923, it matters little. This is the Springsharp report:
F/BB/1923, France Battleship laid down 1923

Displacement:
 47,998 t light; 50,041 t standard; 53,000 t normal; 55,367 t full load

Dimensions: Length overall / water x beam x draught
 789.71 ft / 785.00 ft x 108.00 ft x 33.00 ft (normal load)
 240.70 m / 239.27 m x 32.92 m  x 10.06 m

Armament:
      9 - 16.54" / 420 mm guns (3x3 guns), 2,260.56lbs / 1,025.37kg shells, 1923 Model
   Breech loading guns in turrets (on barbettes)
   on centreline ends, majority forward, 1 raised mount - superfiring
      16 - 5.51" / 140 mm guns (8x2 guns), 83.72lbs / 37.98kg shells, 1923 Model
   Quick firing guns in turrets (on barbettes)
   on side, all amidships, all raised mounts - superfiring
      4 - 3.54" / 90.0 mm guns in single mounts, 22.24lbs / 10.09kg shells, 1923 Model
   Anti-aircraft guns in deck mounts with hoists
   on side, all amidships
      16 - 1.85" / 47.0 mm guns in single mounts, 3.17lbs / 1.44kg shells, 1923 Model
   Anti-aircraft guns in deck mounts 
   on side, evenly spread, 8 raised mounts
 Weight of broadside 21,824 lbs / 9,899 kg
 Shells per gun, main battery: 80

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 14.0" / 356 mm 550.00 ft / 167.64 m 16.00 ft / 4.88 m
 Ends: 5.00" / 127 mm 195.00 ft / 59.44 m 12.00 ft / 3.66 m
   40.00 ft / 12.19 m Unarmoured ends
   Main Belt covers 108 % of normal length

   - Torpedo Bulkhead:
  3.00" / 76 mm 550.00 ft / 167.64 m 30.00 ft / 9.14 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 14.0" / 356 mm 11.0" / 279 mm  14.0" / 356 mm
 2nd: 5.00" / 127 mm 5.00" / 127 mm  5.00" / 127 mm

   - Armour deck: 6.00" / 152 mm, Conning tower: 14.00" / 356 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 4 shafts, 159,715 shp / 119,147 Kw = 29.00 kts
 Range 7,500nm at 15.00 kts
 Bunker at max displacement = 5,327 tons

Complement:
 1,746 - 2,270

Cost:
 £13.727 million / $54.910 million

Distribution of weights at normal displacement:
 Armament: 2,728 tons, 5.1 %
 Armour: 20,003 tons, 37.7 %
    - Belts: 5,688 tons, 10.7 %
    - Torpedo bulkhead: 1,832 tons, 3.5 %
    - Armament: 4,763 tons, 9.0 %
    - Armour Deck: 7,295 tons, 13.8 %
    - Conning Tower: 426 tons, 0.8 %
 Machinery: 5,338 tons, 10.1 %
 Hull, fittings & equipment: 19,928 tons, 37.6 %
 Fuel, ammunition & stores: 5,002 tons, 9.4 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   72,365 lbs / 32,824 Kg = 32.0 x 16.5 " / 420 mm shells or 11.2 torpedoes
 Stability (Unstable if below 1.00): 1.07
 Metacentric height 6.4 ft / 2.0 m
 Roll period: 17.9 seconds
 Steadiness - As gun platform (Average = 50 %): 54 %
   - Recoil effect (Restricted arc if above 1.00): 0.78
 Seaboat quality  (Average = 1.00): 1.09

Hull form characteristics:
 Hull has rise forward of midbreak
 Block coefficient: 0.663
 Length to Beam Ratio: 7.27 : 1
 'Natural speed' for length: 28.02 kts
 Power going to wave formation at top speed: 53 %
 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:  31.00 ft / 9.45 m
    - Forecastle (20 %): 27.00 ft / 8.23 m
    - Mid (67 %):  27.00 ft / 8.23 m (19.00 ft / 5.79 m aft of break)
    - Quarterdeck (15 %): 19.00 ft / 5.79 m
    - Stern:  19.00 ft / 5.79 m
    - Average freeboard: 24.68 ft / 7.52 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 87.5 %
  - Above water (accommodation/working, high = better): 177.7 %
 Waterplane Area: 65,725 Square feet or 6,106 Square metres
 Displacement factor (Displacement / loading): 101 %
 Structure weight / hull surface area: 218 lbs/sq ft or 1,065 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.97
  - Longitudinal: 1.29
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is adequate
 Room for accommodation and workspaces is excellent

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