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Tuesday, January 10, 2006

The US/CL/1916 design

To make the US/CL/1916 design work, lighter machinery was required than was allowed by Springsharp for this date. This ship is basically the US/CL/1914 with the forecastle lengthened, the 5in guns replaced with 6in guns, the armour basis reduced to 3in, and the speed increased to a competitive 33 knots. That meant lengthening the ship to 535ft on the waterline and increasing the displacement to achieve adequate strength. This is the resulting Springsharp report:
US/CL/1916, United States Light Cruiser laid down 1916 (Engine 1937)

Displacement:
 7,570 t light; 7,844 t standard; 8,450 t normal; 8,935 t full load

Dimensions: Length overall / water x beam x draught
 538.82 ft / 535.00 ft x 53.00 ft x 18.00 ft (normal load)
 164.23 m / 163.07 m x 16.15 m  x 5.49 m

Armament:
      6 - 6.00" / 152 mm guns (5 mounts), 108.00lbs / 48.99kg shells, 1916 Model
   Quick firing guns in deck mounts with hoists
   on centreline ends, majority forward, 2 raised mounts - superfiring
      6 - 6.00" / 152 mm guns (4 mounts), 108.00lbs / 48.99kg shells, 1916 Model
   Quick firing guns in deck mounts with hoists
   on side, all amidships
      4 - 4.00" / 102 mm guns (2x2 guns), 32.00lbs / 14.51kg shells, 1916 Model
   Anti-aircraft guns in deck mounts 
   on side, evenly spread
 Weight of broadside 1,424 lbs / 646 kg
 Shells per gun, main battery: 120
 12 - 21.0" / 533.4 mm above water torpedoes

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 3.00" / 76 mm 410.00 ft / 124.97 m 12.00 ft / 3.66 m
 Ends: Unarmoured
   Main Belt covers 118 % of normal length

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

   - Armour deck: 2.00" / 51 mm, Conning tower: 3.00" / 76 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 4 shafts, 93,827 shp / 69,995 Kw = 33.00 kts
 Range 5,400nm at 15.00 kts
 Bunker at max displacement = 1,091 tons

Complement:
 439 - 572

Cost:
 £1.274 million / $5.096 million

Distribution of weights at normal displacement:
 Armament: 178 tons, 2.1 %
 Armour: 1,528 tons, 18.1 %
    - Belts: 601 tons, 7.1 %
    - Torpedo bulkhead: 0 tons, 0.0 %
    - Armament: 147 tons, 1.7 %
    - Armour Deck: 753 tons, 8.9 %
    - Conning Tower: 27 tons, 0.3 %
 Machinery: 2,601 tons, 30.8 %
 Hull, fittings & equipment: 3,264 tons, 38.6 %
 Fuel, ammunition & stores: 880 tons, 10.4 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   8,376 lbs / 3,799 Kg = 77.6 x 6.0 " / 152 mm shells or 1.1 torpedoes
 Stability (Unstable if below 1.00): 1.21
 Metacentric height 2.8 ft / 0.8 m
 Roll period: 13.4 seconds
 Steadiness - As gun platform (Average = 50 %): 53 %
   - Recoil effect (Restricted arc if above 1.00): 0.53
 Seaboat quality  (Average = 1.00): 1.06

Hull form characteristics:
 Hull has rise forward of midbreak
 Block coefficient: 0.579
 Length to Beam Ratio: 10.09 : 1
 'Natural speed' for length: 23.13 kts
 Power going to wave formation at top speed: 62 %
 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:  26.00 ft / 7.92 m
    - Forecastle (20 %): 23.00 ft / 7.01 m
    - Mid (67 %):  23.00 ft / 7.01 m (15.00 ft / 4.57 m aft of break)
    - Quarterdeck (15 %): 15.00 ft / 4.57 m
    - Stern:  15.00 ft / 4.57 m
    - Average freeboard: 20.60 ft / 6.28 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 116.0 %
  - Above water (accommodation/working, high = better): 130.0 %
 Waterplane Area: 20,343 Square feet or 1,890 Square metres
 Displacement factor (Displacement / loading): 104 %
 Structure weight / hull surface area: 93 lbs/sq ft or 453 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.93
  - Longitudinal: 1.85
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is cramped
 Room for accommodation and workspaces is excellent

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