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Thursday, January 03, 2008

A British fast battleship

I was dismayed at the size of ship that was necessary to have a 32 knot British battleship with 9-16in/45 guns. The side armour is substantial, as it is 17ft high and a uniform 16in, inclined outward at 16 degrees. To do that in Springsharp took a ship that is 59,061 tons Standard displacement. This is the Springsharp report:
GB/BB/1939, Great Britain Battleship laid down 1939 (Engine 1950)

Displacement:
 56,457 t light; 59,061 t standard; 62,990 t normal; 66,133 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
 (869.23 ft / 862.00 ft) x 118.00 ft x (33.50 / 34.88 ft)
 (264.94 m / 262.74 m) x 35.97 m  x (10.21 / 10.63 m)

Armament:
      9 - 16.00" / 406 mm 45.0 cal guns - 2,100.00lbs / 952.54kg shells, 120 per gun
   Breech loading guns in turret on barbette mounts, 1939 Model
   3 x Triple mounts on centreline ends, majority forward
  1 raised mount - superfiring
      20 - 4.50" / 114 mm 45.0 cal guns - 45.95lbs / 20.84kg shells, 150 per gun
   Dual purpose guns in turret on barbette mounts, 1939 Model
   10 x Twin mounts on sides, evenly spread
  4 raised mounts
      48 - 1.57" / 40.0 mm 45.0 cal guns - 2.00lbs / 0.91kg shells, 150 per gun
   Anti-air guns in deck mounts, 1939 Model
   8 x 2 row sextuple mounts on sides, evenly spread
  8 raised mounts
      Weight of broadside 19,915 lbs / 9,033 kg

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 16.0" / 406 mm 565.00 ft / 172.21 m 17.00 ft / 5.18 m
 Ends: Unarmoured
   Main Belt covers 101 % of normal length

   - Torpedo Bulkhead:
  6.00" / 152 mm 565.00 ft / 172.21 m 33.50 ft / 10.21 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 16.0" / 406 mm 12.0" / 305 mm  16.0" / 406 mm
 2nd: 3.00" / 76 mm 2.00" / 51 mm  3.00" / 76 mm

   - Armoured deck - multiple decks: 7.00" / 178 mm For and Aft decks
 Forecastle: 7.00" / 178 mm  Quarter deck: 7.00" / 178 mm

   - Conning towers: Forward 12.00" / 305 mm,  Aft 0.00" / 0 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 4 shafts, 233,559 shp / 174,235 Kw = 32.00 kts
 Range 8,500nm at 17.00 kts
 Bunker at max displacement = 7,071 tons

Complement:
 1,987 - 2,584

Cost:
 £26.676 million / $106.702 million

Distribution of weights at normal displacement:
 Armament: 3,267 tons, 5.2 %
 Armour: 26,305 tons, 41.8 %
    - Belts: 6,629 tons, 10.5 %
    - Torpedo bulkhead: 4,202 tons, 6.7 %
    - Armament: 4,657 tons, 7.4 %
    - Armour Deck: 10,408 tons, 16.5 %
    - Conning Tower: 409 tons, 0.6 %
 Machinery: 5,588 tons, 8.9 %
 Hull, fittings & equipment: 21,297 tons, 33.8 %
 Fuel, ammunition & stores: 6,533 tons, 10.4 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   117,729 lbs / 53,401 Kg = 57.5 x 16.0 " / 406 mm shells or 25.4 torpedoes
 Stability (Unstable if below 1.00): 1.23
 Metacentric height 9.4 ft / 2.9 m
 Roll period: 16.2 seconds
 Steadiness - As gun platform (Average = 50 %): 52 %
   - Recoil effect (Restricted arc if above 1.00): 0.44
 Seaboat quality  (Average = 1.00): 1.04

Hull form characteristics:
 Hull has a flush deck,
   an extended bulbous bow and small transom stern
 Block coefficient (normal/deep): 0.647 / 0.652
 Length to Beam Ratio: 7.31 : 1
 'Natural speed' for length: 31.67 kts
 Power going to wave formation at top speed: 55 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 12.00 degrees
 Stern overhang: 0.00 ft / 0.00 m
 Freeboard (% = length of deck as a percentage of waterline length):
    Fore end,  Aft end
    - Forecastle: 20.00 %,  34.00 ft / 10.36 m,  27.00 ft / 8.23 m
    - Forward deck: 30.00 %,  27.00 ft / 8.23 m,  24.00 ft / 7.32 m
    - Aft deck: 35.00 %,  24.00 ft / 7.32 m,  24.00 ft / 7.32 m
    - Quarter deck: 15.00 %,  24.00 ft / 7.32 m,  24.00 ft / 7.32 m
    - Average freeboard:  25.61 ft / 7.81 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 67.7 %
  - Above water (accommodation/working, high = better): 188.7 %
 Waterplane Area: 79,722 Square feet or 7,406 Square metres
 Displacement factor (Displacement / loading): 115 %
 Structure weight / hull surface area: 210 lbs/sq ft or 1,026 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.98
  - Longitudinal: 1.20
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is excellent
 Room for accommodation and workspaces is excellent

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