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Thursday, December 08, 2005

A new GB/CL/1914 design

This is inspired by the sort of ship the Russians were building at the beginning of WWI. I wanted a multi-purpose light cruiser with decent protection and armament with a 30 knot speed. The armament is 7-6in QF, 2-3in AA, and 4-21in TT. The belt is 4in and the deck is 2in. The range is 5,000nm at 15 knots. This is the Springsharp report:
GB/CL/1914, Great Britain Light Cruiser laid down 1914

Displacement:
 6,618 t light; 6,836 t standard; 7,600 t normal; 8,211 t full load

Dimensions: Length overall / water x beam x draught
 513.31 ft / 512.00 ft x 52.00 ft x 18.00 ft (normal load)
 156.46 m / 156.06 m x 15.85 m  x 5.49 m

Armament:
      7 - 6.00" / 152 mm guns in single mounts, 108.00lbs / 48.99kg shells, 1914 Model
   Quick firing guns in deck mounts with hoists
   on centreline ends, majority forward, 2 raised mounts - superfiring
      2 - 3.00" / 76.2 mm guns in single mounts, 13.50lbs / 6.12kg shells, 1914 Model
   Anti-aircraft guns in deck mounts with hoists
   on side, all amidships
 Weight of broadside 783 lbs / 355 kg
 Shells per gun, main battery: 150
 4 - 21.0" / 533.4 mm above water torpedoes

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 4.00" / 102 mm 390.00 ft / 118.87 m 12.00 ft / 3.66 m
 Ends: Unarmoured
   Main Belt covers 117 % of normal length

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 2.00" / 51 mm       -   2.00" / 51 mm

   - Armour deck: 2.00" / 51 mm, Conning tower: 4.00" / 102 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Direct drive, 4 shafts, 59,938 shp / 44,714 Kw = 30.00 kts
 Range 5,000nm at 15.00 kts
 Bunker at max displacement = 1,376 tons

Complement:
 406 - 529

Cost:
 £0.811 million / $3.243 million

Distribution of weights at normal displacement:
 Armament: 98 tons, 1.3 %
 Armour: 1,540 tons, 20.3 %
    - Belts: 764 tons, 10.0 %
    - Torpedo bulkhead: 0 tons, 0.0 %
    - Armament: 53 tons, 0.7 %
    - Armour Deck: 691 tons, 9.1 %
    - Conning Tower: 33 tons, 0.4 %
 Machinery: 2,309 tons, 30.4 %
 Hull, fittings & equipment: 2,671 tons, 35.1 %
 Fuel, ammunition & stores: 982 tons, 12.9 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   8,682 lbs / 3,938 Kg = 80.4 x 6.0 " / 152 mm shells or 1.2 torpedoes
 Stability (Unstable if below 1.00): 1.28
 Metacentric height 2.9 ft / 0.9 m
 Roll period: 12.8 seconds
 Steadiness - As gun platform (Average = 50 %): 65 %
   - Recoil effect (Restricted arc if above 1.00): 0.33
 Seaboat quality  (Average = 1.00): 1.30

Hull form characteristics:
 Hull has rise forward of midbreak
 Block coefficient: 0.555
 Length to Beam Ratio: 9.85 : 1
 'Natural speed' for length: 22.63 kts
 Power going to wave formation at top speed: 58 %
 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 (% = measuring location as a percentage of overall length):
    - Stem:  25.00 ft / 7.62 m
    - Forecastle (20 %): 22.00 ft / 6.71 m
    - Mid (67 %):  22.00 ft / 6.71 m (14.00 ft / 4.27 m aft of break)
    - Quarterdeck (15 %): 14.00 ft / 4.27 m
    - Stern:  14.00 ft / 4.27 m
    - Average freeboard: 19.60 ft / 5.97 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 108.8 %
  - Above water (accommodation/working, high = better): 155.3 %
 Waterplane Area: 18,669 Square feet or 1,734 Square metres
 Displacement factor (Displacement / loading): 109 %
 Structure weight / hull surface area: 83 lbs/sq ft or 407 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.94
  - Longitudinal: 1.75
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is adequate
 Room for accommodation and workspaces is excellent
 Good seaboat, rides out heavy weather easily

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