The GB/CL/1916 design

This is my GB/CL/1916 design for a cruiser designed for overseas service and convoying. This type is intended to replace ships such as the cruisers Challenger and Highflyer. Good seakeeping is therefore a priority with a sufficient gun armament to fight German raiding light cruisers, if any were to be dispatched. This is the Springsharp report:

GB/CL/1916, Great Britain Light Cruiser laid down 1916 (Engine 1919)

Displacement:
 6,391 t light; 6,640 t standard; 7,436 t normal; 8,072 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
 (528.07 ft / 525.00 ft) x 51.00 ft x (18.00 / 19.20 ft)
 (160.96 m / 160.02 m) x 15.54 m  x (5.49 / 5.85 m)

Armament:
      10 - 6.00" / 152 mm 50.0 cal guns - 114.33lbs / 51.86kg shells, 150 per gun
   Quick firing guns in deck and hoist mounts, 1916 Model
   2 x Twin mounts on centreline aft
   6 x Single mounts on sides, forward deck aft
      Weight of broadside 1,143 lbs / 519 kg
      4 - 21.0" / 533 mm, 20.00 ft / 6.10 m torpedoes - 1.287 t each, 5.148 t total
 In 2 sets of deck mounted side rotating tubes

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 3.00" / 76 mm 410.00 ft / 124.97 m 8.00 ft / 2.44 m
 Ends: Unarmoured
 Upper: 3.00" / 76 mm 300.00 ft / 91.44 m 8.00 ft / 2.44 m
   Main Belt covers 120 % of normal length
   Main belt does not fully cover magazines and engineering spaces

   - Torpedo Bulkhead:
  0.70" / 18 mm 410.00 ft / 124.97 m 17.00 ft / 5.18 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 4.00" / 102 mm 3.00" / 76 mm  4.00" / 102 mm

   - Protected deck - single deck: 2.00" / 51 mm For and Aft decks
 Forecastle: 2.00" / 51 mm  Quarter deck: 2.00" / 51 mm

   - Conning towers: Forward 4.00" / 102 mm,  Aft 0.00" / 0 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 2 shafts, 43,738 shp / 32,628 Kw = 28.00 kts
 Range 5,500nm at 16.00 kts
 Bunker at max displacement = 1,432 tons

Complement:
 399 - 520

Cost:
 £0.918 million / $3.673 million

Distribution of weights at normal displacement:
 Armament: 326 tons, 4.4 %
    - Guns: 321 tons, 4.3 %
    - Torpedoes: 5 tons, 0.1 %
 Armour: 1,799 tons, 24.2 %
    - Belts: 694 tons, 9.3 %
    - Torpedo bulkhead: 181 tons, 2.4 %
    - Armament: 203 tons, 2.7 %
    - Armour Deck: 689 tons, 9.3 %
    - Conning Tower: 33 tons, 0.4 %
 Machinery: 1,553 tons, 20.9 %
 Hull, fittings & equipment: 2,713 tons, 36.5 %
 Fuel, ammunition & stores: 1,045 tons, 14.1 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   11,955 lbs / 5,423 Kg = 110.7 x 6.0 " / 152 mm shells or 1.9 torpedoes
 Stability (Unstable if below 1.00): 1.07
 Metacentric height 2.1 ft / 0.6 m
 Roll period: 14.8 seconds
 Steadiness - As gun platform (Average = 50 %): 83 %
   - Recoil effect (Restricted arc if above 1.00): 0.74
 Seaboat quality  (Average = 1.00): 1.66

Hull form characteristics:
 Hull has low quarterdeck ,
   a normal bow and a cruiser stern
 Block coefficient (normal/deep): 0.540 / 0.549
 Length to Beam Ratio: 10.29 : 1
 'Natural speed' for length: 22.91 kts
 Power going to wave formation at top speed: 53 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 7.00 degrees
 Stern overhang: -3.00 ft / -0.91 m
 Freeboard (% = length of deck as a percentage of waterline length):
    Fore end,  Aft end
    - Forecastle: 25.00 %,  25.00 ft / 7.62 m,  23.00 ft / 7.01 m
    - Forward deck: 25.00 %,  23.00 ft / 7.01 m,  22.00 ft / 6.71 m
    - Aft deck: 21.00 %,  22.00 ft / 6.71 m,  22.00 ft / 6.71 m
    - Quarter deck: 29.00 %,  14.00 ft / 4.27 m,  15.00 ft / 4.57 m
    - Average freeboard:  20.40 ft / 6.22 m
 Ship tends to be wet forward

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 136.9 %
  - Above water (accommodation/working, high = better): 192.9 %
 Waterplane Area: 18,512 Square feet or 1,720 Square metres
 Displacement factor (Displacement / loading): 123 %
 Structure weight / hull surface area: 87 lbs/sq ft or 423 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.93
  - Longitudinal: 1.92
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is cramped
 Room for accommodation and workspaces is excellent
 Ship has slow, easy roll, a good, steady gun platform
 Excellent seaboat, comfortable, can fire her guns in the heaviest weather