D. K. Brown's concept for the GB/CB/1907

Back in 2001, D. K. Brown, the naval architect and author, told me that my battlecruiser design needed eight guns and 6in side armour to really be viable. I thought that it would be interesting to apply that to the GB/CB/1907 design that I did earlier today. The speed necessarily has to be reduced (to 34 knots). I modifed the secondary armament to be 10-6in QF guns. That actually was my friend Cliff's original concept, but he decided that he could put one gun on the centerline aft, in a superfiring position, and still get the same broadside with one less gun. This is the Springsharp report:

GB/CB/1907 very fast (Alt version), Great Britain Battlecruiser laid down 1907 (Engine 1927)

Displacement:
    24,643 t light; 25,621 t standard; 28,450 t normal; 30,713 t full load

Dimensions: Length overall / water x beam x draught
    770.00 ft / 770.00 ft x 88.00 ft x 28.00 ft (normal load)
    234.70 m / 234.70 m x 26.82 m  x 8.53 m

Armament:
      8 - 12.00" / 305 mm guns (4x2 guns), 864.00lbs / 391.90kg shells, 1907 Model
      Breech loading guns in turrets (on barbettes)
      on centreline ends, evenly spread
      10 - 6.00" / 152 mm guns in single mounts, 108.00lbs / 48.99kg shells, 1907 Model
      Quick firing guns in deck mounts with hoists
      on side, all amidships
    Weight of broadside 7,992 lbs / 3,625 kg
    Shells per gun, main battery: 90

Armour:
   - Belts:        Width (max)    Length (avg)        Height (avg)
    Main:    6.00" / 152 mm    465.00 ft / 141.73 m    8.00 ft / 2.44 m
    Ends:    Unarmoured
    Upper:    6.00" / 152 mm    345.00 ft / 105.16 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    550.00 ft / 167.64 m    27.00 ft / 8.23 m

   - Gun armour:    Face (max)    Other gunhouse (avg)    Barbette/hoist (max)
    Main:    8.00" / 203 mm    5.00" / 127 mm        7.00" / 178 mm
    2nd:    4.00" / 102 mm    4.00" / 102 mm        4.00" / 102 mm

   - Armour deck: 2.00" / 51 mm, Conning tower: 8.00" / 203 mm

Machinery:
    Oil fired boilers, steam turbines,
    Direct drive, 4 shafts, 190,436 shp / 142,065 Kw = 34.00 kts
    Range 7,500nm at 18.00 kts
    Bunker at max displacement = 5,093 tons

Complement:
    1,094 - 1,423

Cost:
    £2.543 million / $10.173 million

Distribution of weights at normal displacement:
    Armament: 999 tons, 3.5 %
    Armour: 6,214 tons, 21.8 %
       - Belts: 1,704 tons, 6.0 %
       - Torpedo bulkhead: 1,099 tons, 3.9 %
       - Armament: 1,542 tons, 5.4 %
       - Armour Deck: 1,709 tons, 6.0 %
       - Conning Tower: 161 tons, 0.6 %
    Machinery: 6,011 tons, 21.1 %
    Hull, fittings & equipment: 11,419 tons, 40.1 %
    Fuel, ammunition & stores: 3,807 tons, 13.4 %
    Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
    Survivability (Non-critical penetrating hits needed to sink ship):
      36,969 lbs / 16,769 Kg = 42.8 x 12.0 " / 305 mm shells or 4.6 torpedoes
    Stability (Unstable if below 1.00): 1.19
    Metacentric height 5.7 ft / 1.7 m
    Roll period: 15.5 seconds
    Steadiness    - As gun platform (Average = 50 %): 60 %
            - Recoil effect (Restricted arc if above 1.00): 0.60
    Seaboat quality  (Average = 1.00): 1.19

Hull form characteristics:
    Hull has rise forward of midbreak
    Block coefficient: 0.525
    Length to Beam Ratio: 8.75 : 1
    'Natural speed' for length: 27.75 kts
    Power going to wave formation at top speed: 56 %
    Trim (Max stability = 0, Max steadiness = 100): 50
    Bow angle (Positive = bow angles forward): -2.00 degrees
    Stern overhang: -2.00 ft / -0.61 m
    Freeboard (% = measuring location as a percentage of overall length):
       - Stem:        34.00 ft / 10.36 m
       - Forecastle (20 %):    29.00 ft / 8.84 m
       - Mid (73 %):        29.00 ft / 8.84 m (21.00 ft / 6.40 m aft of break)
       - Quarterdeck (15 %):    21.00 ft / 6.40 m
       - Stern:        21.00 ft / 6.40 m
       - Average freeboard:    27.24 ft / 8.30 m

Ship space, strength and comments:
    Space    - Hull below water (magazines/engines, low = better): 122.9 %
        - Above water (accommodation/working, high = better): 221.3 %
    Waterplane Area: 46,191 Square feet or 4,291 Square metres
    Displacement factor (Displacement / loading): 108 %
    Structure weight / hull surface area: 160 lbs/sq ft or 779 Kg/sq metre
    Hull strength (Relative):
        - Cross-sectional: 0.96
        - Longitudinal: 1.44
        - Overall: 1.00
    Hull space for machinery, storage, compartmentation is cramped
    Room for accommodation and workspaces is excellent