Another look at the British semi-Dreadnought: GB/BB/1903

The British almost built a class of battleships that were in the "semi-Dreadnought" category. They would have carried 4-12in and 12-9.2in guns. They were what the Lord Nelson and Agamenon should have been. This is the Springsharp report:

GB/BB/1903, Great Britain Battleship laid down 1903 (Engine 1908)

Displacement:
 18,189 t light; 19,180 t standard; 21,093 t normal; 22,623 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
 (483.00 ft / 475.00 ft) x 82.00 ft x (27.00 / 28.71 ft)
 (147.22 m / 144.78 m) x 24.99 m  x (8.23 / 8.75 m)

Armament:
      4 - 12.00" / 305 mm 45.0 cal guns - 850.00lbs / 385.55kg shells, 90 per gun
   Breech loading guns in turret on barbette mounts, 1903 Model
   2 x Twin mounts on centreline ends, evenly spread
      12 - 9.20" / 234 mm 50.0 cal guns - 380.00lbs / 172.37kg shells, 150 per gun
   Breech loading guns in turret on barbette mounts, 1903 Model
   6 x Twin mounts on sides, evenly spread
      16 - 3.00" / 76.2 mm 50.0 cal guns - 14.29lbs / 6.48kg shells, 150 per gun
   Quick firing guns in deck and hoist mounts, 1903 Model
   16 x Single mounts on sides, evenly spread
  16 raised mounts
      Weight of broadside 8,189 lbs / 3,714 kg

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 12.0" / 305 mm 315.00 ft / 96.01 m 9.00 ft / 2.74 m
 Ends: 5.00" / 127 mm 160.00 ft / 48.77 m 16.00 ft / 4.88 m
 Upper: 9.00" / 229 mm 315.00 ft / 96.01 m 8.00 ft / 2.44 m
   Main Belt covers 102 % of normal length

   - Torpedo Bulkhead - Additional damage containing bulkheads:
  2.00" / 51 mm 315.00 ft / 96.01 m 27.00 ft / 8.23 m
 Beam between torpedo bulkheads 58.00 ft / 17.68 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 12.0" / 305 mm 9.00" / 229 mm  12.0" / 305 mm
 2nd: 10.0" / 254 mm 7.00" / 178 mm  10.0" / 254 mm
 3rd: 2.00" / 51 mm 2.00" / 51 mm  2.00" / 51 mm

   - Armoured deck - multiple decks:
 For and Aft decks: 3.00" / 76 mm
 Forecastle: 3.00" / 76 mm  Quarter deck: 3.00" / 76 mm

   - Conning towers: Forward 12.00" / 305 mm, Aft 9.00" / 229 mm

Machinery:
 Coal fired boilers, complex reciprocating steam engines, 
 Direct drive, 4 shafts, 21,257 ihp / 15,857 Kw = 19.00 kts
 Range 4,500nm at 14.00 kts
 Bunker at max displacement = 3,443 tons (100% coal)

Complement:
 874 - 1,137

Cost:
 £1.772 million / $7.089 million

Distribution of weights at normal displacement:
 Armament: 1,918 tons, 9.1 %
    - Guns: 1,918 tons, 9.1 %
 Armour: 8,378 tons, 39.7 %
    - Belts: 3,019 tons, 14.3 %
    - Torpedo bulkhead: 629 tons, 3.0 %
    - Armament: 2,635 tons, 12.5 %
    - Armour Deck: 1,749 tons, 8.3 %
    - Conning Towers: 345 tons, 1.6 %
 Machinery: 1,932 tons, 9.2 %
 Hull, fittings & equipment: 5,961 tons, 28.3 %
 Fuel, ammunition & stores: 2,904 tons, 13.8 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   30,266 lbs / 13,728 Kg = 35.0 x 12.0 " / 305 mm shells or 5.1 torpedoes
 Stability (Unstable if below 1.00): 1.12
 Metacentric height 4.6 ft / 1.4 m
 Roll period: 16.1 seconds
 Steadiness - As gun platform (Average = 50 %): 79 %
   - Recoil effect (Restricted arc if above 1.00): 0.76
 Seaboat quality  (Average = 1.00): 1.59

Hull form characteristics:
 Hull has a flush deck,
   a ram bow and a cruiser stern
 Block coefficient (normal/deep): 0.702 / 0.708
 Length to Beam Ratio: 5.79 : 1
 'Natural speed' for length: 21.79 kts
 Power going to wave formation at top speed: 48 %
 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: 20.00 %,  22.00 ft / 6.71 m,  21.00 ft / 6.40 m
    - Forward deck: 30.00 %,  21.00 ft / 6.40 m,  19.00 ft / 5.79 m
    - Aft deck: 30.00 %,  19.00 ft / 5.79 m,  20.00 ft / 6.10 m
    - Quarter deck: 20.00 %,  20.00 ft / 6.10 m,  21.00 ft / 6.40 m
    - Average freeboard:  20.23 ft / 6.17 m
 Ship tends to be wet forward

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 95.4 %
  - Above water (accommodation/working, high = better): 134.6 %
 Waterplane Area: 31,275 Square feet or 2,906 Square metres
 Displacement factor (Displacement / loading): 103 %
 Structure weight / hull surface area: 154 lbs/sq ft or 752 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.93
  - Longitudinal: 1.93
  - Overall: 1.00
 Adequate machinery, storage, compartmentation space
 Excellent accommodation and workspace room
 Ship has slow, easy roll, a good, steady gun platform
 Excellent seaboat, comfortable, can fire her guns in the heaviest weather