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Monday, January 09, 2006

A new series starting with the US/CL/1914

In a lost series of drawings from 1976, I had this concept for an American light cruiser for 1914 or thereabouts. The design is rather like the British Town class, except with 5in guns. I had thought that the 5in/51 QF gun had a good range and rate of fire, probably with a 60 lb. shot/shell, so that the piece was still fairly hard-hitting. This is the Springsharp report:
US/CL/1914, United States Light Cruiser laid down 1914

Displacement:
 5,645 t light; 5,842 t standard; 6,600 t normal; 7,206 t full load

Dimensions: Length overall / water x beam x draught
 478.75 ft / 475.00 ft x 49.00 ft x 17.00 ft (normal load)
 145.92 m / 144.78 m x 14.94 m  x 5.18 m

Armament:
      5 - 5.00" / 127 mm guns in single mounts, 62.50lbs / 28.35kg shells, 1914 Model
   Quick firing guns in deck mounts with hoists
   on centreline ends, majority forward, 2 raised mounts - superfiring
      4 - 5.00" / 127 mm guns in single mounts, 62.50lbs / 28.35kg shells, 1914 Model
   Quick firing guns in deck mounts with hoists
   on side, all amidships
      2 - 3.00" / 76.2 mm guns in single mounts, 13.50lbs / 6.12kg shells, 1914 Model
   Anti-aircraft guns in deck mounts 
   on side, evenly spread
 Weight of broadside 590 lbs / 267 kg
 Shells per gun, main battery: 180
 4 - 21.0" / 533.4 mm above water torpedoes

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 4.00" / 102 mm 400.00 ft / 121.92 m 12.00 ft / 3.66 m
 Ends: Unarmoured
   Main Belt covers 130 % of normal length

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 4.00" / 102 mm 2.00" / 51 mm  3.00" / 76 mm
 2nd: 4.00" / 102 mm 2.00" / 51 mm  3.00" / 76 mm

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

Machinery:
 Oil fired boilers, steam turbines, 
 Direct drive, 4 shafts, 50,206 shp / 37,454 Kw = 29.00 kts
 Range 5,400nm at 15.00 kts
 Bunker at max displacement = 1,364 tons

Complement:
 365 - 475

Cost:
 £0.675 million / $2.699 million

Distribution of weights at normal displacement:
 Armament: 74 tons, 1.1 %
 Armour: 1,523 tons, 23.1 %
    - Belts: 773 tons, 11.7 %
    - Torpedo bulkhead: 0 tons, 0.0 %
    - Armament: 99 tons, 1.5 %
    - Armour Deck: 620 tons, 9.4 %
    - Conning Tower: 30 tons, 0.5 %
 Machinery: 1,934 tons, 29.3 %
 Hull, fittings & equipment: 2,115 tons, 32.0 %
 Fuel, ammunition & stores: 955 tons, 14.5 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   7,519 lbs / 3,410 Kg = 120.3 x 5.0 " / 127 mm shells or 1.2 torpedoes
 Stability (Unstable if below 1.00): 1.31
 Metacentric height 2.8 ft / 0.8 m
 Roll period: 12.3 seconds
 Steadiness - As gun platform (Average = 50 %): 54 %
   - Recoil effect (Restricted arc if above 1.00): 0.22
 Seaboat quality  (Average = 1.00): 1.07

Hull form characteristics:
 Hull has rise forward of midbreak
 Block coefficient: 0.584
 Length to Beam Ratio: 9.69 : 1
 'Natural speed' for length: 21.79 kts
 Power going to wave formation at top speed: 59 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 4.00 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 (37 %):  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: 17.20 ft / 5.24 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 104.3 %
  - Above water (accommodation/working, high = better): 124.1 %
 Waterplane Area: 16,767 Square feet or 1,558 Square metres
 Displacement factor (Displacement / loading): 110 %
 Structure weight / hull surface area: 77 lbs/sq ft or 377 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.96
  - Longitudinal: 1.40
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is adequate
 Room for accommodation and workspaces is excellent

1 comment:

Simon Langer said...

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I'll come by again.

Many thanks,

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