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Friday, September 07, 2007

The GB/BB/1910 design study revisited

If my friend Cliff had decided to build battleships for 1910, instead of battlecruiser, he was considering building the GB/BB/1910 design. He had me prepare a preliminary design for him. This was a ship armed with just 6-13.5in guns. I have added a secondary battery of 14-4in guns, as they would have been part of the design. Cliff liked heavy armour, so the ship has a 14in belt, turret faces, and barbettes. He was determined that the standard displacement be 29,000 tons. This is the Springsharp report:
GB/BB/1910, Great Britain Battleship laid down 1910

Displacement:
 27,726 t light; 28,814 t standard; 32,272 t normal; 35,039 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
 (626.00 ft / 620.00 ft) x 95.00 ft x (30.20 / 32.38 ft)
 (190.80 m / 188.98 m) x 28.96 m  x (9.20 / 9.87 m)

Armament:
      6 - 13.50" / 343 mm 45.0 cal guns - 1,350.00lbs / 612.35kg shells, 90 per gun
   Breech loading guns in turret on barbette mounts, 1910 Model
   3 x Twin mounts on centreline ends, evenly spread
  1 raised mount - superfiring
      14 - 4.00" / 102 mm 45.0 cal guns - 32.27lbs / 14.64kg shells, 150 per gun
   Quick firing guns in deck and hoist mounts, 1910 Model
   14 x Single mounts on sides, forward deck aft
  2 raised mounts - superfiring
      Weight of broadside 8,552 lbs / 3,879 kg

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 14.0" / 356 mm 375.00 ft / 114.30 m 8.00 ft / 2.44 m
 Ends: Unarmoured
 Upper: 9.00" / 229 mm 375.00 ft / 114.30 m 8.00 ft / 2.44 m
   Main Belt covers 93 % of normal length
   Main belt does not fully cover magazines and engineering spaces

   - Torpedo Bulkhead:
  2.00" / 51 mm 375.00 ft / 114.30 m 30.20 ft / 9.20 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 14.0" / 356 mm 10.0" / 254 mm  14.0" / 356 mm
 2nd: 4.00" / 102 mm 2.00" / 51 mm  4.00" / 102 mm

   - Armoured deck - multiple decks: 5.00" / 127 mm For and Aft decks
 Forecastle: 5.00" / 127 mm  Quarter deck: 5.00" / 127 mm

   - Conning towers: Forward 14.00" / 356 mm,  Aft 0.00" / 0 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Direct drive, 4 shafts, 129,984 shp / 96,968 Kw = 29.00 kts
 Range 8,000nm at 15.00 kts
 Bunker at max displacement = 6,224 tons

Complement:
 1,203 - 1,565

Cost:
 £2.460 million / $9.842 million

Distribution of weights at normal displacement:
 Armament: 1,404 tons, 4.3 %
 Armour: 10,729 tons, 33.2 %
    - Belts: 3,054 tons, 9.5 %
    - Torpedo bulkhead: 838 tons, 2.6 %
    - Armament: 2,384 tons, 7.4 %
    - Armour Deck: 4,147 tons, 12.9 %
    - Conning Tower: 306 tons, 0.9 %
 Machinery: 5,371 tons, 16.6 %
 Hull, fittings & equipment: 10,223 tons, 31.7 %
 Fuel, ammunition & stores: 4,546 tons, 14.1 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   46,581 lbs / 21,129 Kg = 37.9 x 13.5 " / 343 mm shells or 6.6 torpedoes
 Stability (Unstable if below 1.00): 1.22
 Metacentric height 6.7 ft / 2.0 m
 Roll period: 15.5 seconds
 Steadiness - As gun platform (Average = 50 %): 52 %
   - Recoil effect (Restricted arc if above 1.00): 0.44
 Seaboat quality  (Average = 1.00): 1.03

Hull form characteristics:
 Hull has rise forward of midbreak,
   a ram bow and a cruiser stern
 Block coefficient (normal/deep): 0.635 / 0.643
 Length to Beam Ratio: 6.53 : 1
 'Natural speed' for length: 24.90 kts
 Power going to wave formation at top speed: 60 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): -3.00 degrees
 Stern overhang: -2.00 ft / -0.61 m
 Freeboard (% = length of deck as a percentage of waterline length):
    Fore end,  Aft end
    - Forecastle: 30.00 %,  29.00 ft / 8.84 m,  27.00 ft / 8.23 m
    - Forward deck: 38.00 %,  27.00 ft / 8.23 m,  27.00 ft / 8.23 m
    - Aft deck: 17.00 %,  19.00 ft / 5.79 m,  19.00 ft / 5.79 m
    - Quarter deck: 15.00 %,  19.00 ft / 5.79 m,  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): 95.3 %
  - Above water (accommodation/working, high = better): 172.8 %
 Waterplane Area: 44,502 Square feet or 4,134 Square metres
 Displacement factor (Displacement / loading): 113 %
 Structure weight / hull surface area: 167 lbs/sq ft or 814 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.94
  - Longitudinal: 1.80
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is adequate
 Room for accommodation and workspaces is excellent

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