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Saturday, October 14, 2006

The Heavily-Armed Battleship from the January 1902 Senior Officer's War Course

On page 15 of John Robert's book, Battlecruisers (about British battlecruisers), he has the high-level specification for a heavily-armed battleship and a lightly-armed battleship that were used in the "Senior Officers' War Course, January 1902". There are no dimensions, just a displacement, speed, armament, and armour. I extrapolated from that description to create a Springsharp design:
GB/BB/1902 Heavily Armed, Great Britain Battleship laid down 1902

Displacement:
 14,614 t light; 15,372 t standard; 17,604 t normal; 19,390 t full load

Dimensions: Length overall / water x beam x draught
 480.00 ft / 480.00 ft x 78.00 ft x 25.00 ft (normal load)
 146.30 m / 146.30 m x 23.77 m  x 7.62 m

Armament:
      4 - 12.00" / 305 mm guns (2x2 guns), 864.00lbs / 391.90kg shells, 1902 Model
   Breech loading guns in turrets (on barbettes)
   on centreline ends, evenly spread
      8 - 8.00" / 203 mm guns (4x2 guns), 256.00lbs / 116.12kg shells, 1902 Model
   Breech loading guns in turrets (on barbettes)
   on side, all amidships
      12 - 7.00" / 178 mm guns in single mounts, 171.50lbs / 77.79kg shells, 1902 Model
   Breech loading guns in casemate mounts 
   on side, evenly spread
   12 guns in hull casemates - Limited use in heavy seas
 Weight of broadside 7,562 lbs / 3,430 kg
 Shells per gun, main battery: 90

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 10.0" / 254 mm 360.00 ft / 109.73 m 8.00 ft / 2.44 m
 Ends: 8.00" / 203 mm 120.00 ft / 36.58 m 8.00 ft / 2.44 m
 Upper: 6.00" / 152 mm 360.00 ft / 109.73 m 8.00 ft / 2.44 m
   Main Belt covers 115 % of normal length

   - Torpedo Bulkhead:
  1.50" / 38 mm 360.00 ft / 109.73 m 25.00 ft / 7.62 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 11.0" / 279 mm 7.00" / 178 mm  11.0" / 279 mm
 2nd: 8.00" / 203 mm 5.00" / 127 mm  8.00" / 203 mm
 3rd: 7.00" / 178 mm 7.00" / 178 mm  7.00" / 178 mm

   - Armour deck: 1.50" / 38 mm, Conning tower: 11.00" / 279 mm

Machinery:
 Coal fired boilers, complex reciprocating steam engines, 
 Direct drive, 2 shafts, 15,182 ihp / 11,326 Kw = 18.00 kts
 Range 4,600nm at 15.00 kts
 Bunker at max displacement = 4,018 tons (100% coal)

Complement:
 763 - 993

Cost:
 £1.628 million / $6.510 million

Distribution of weights at normal displacement:
 Armament: 945 tons, 5.4 %
 Armour: 5,618 tons, 31.9 %
    - Belts: 2,251 tons, 12.8 %
    - Torpedo bulkhead: 500 tons, 2.8 %
    - Armament: 1,905 tons, 10.8 %
    - Armour Deck: 802 tons, 4.6 %
    - Conning Tower: 160 tons, 0.9 %
 Machinery: 2,300 tons, 13.1 %
 Hull, fittings & equipment: 5,750 tons, 32.7 %
 Fuel, ammunition & stores: 2,990 tons, 17.0 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   21,422 lbs / 9,717 Kg = 24.8 x 12.0 " / 305 mm shells or 3.4 torpedoes
 Stability (Unstable if below 1.00): 1.20
 Metacentric height 4.8 ft / 1.5 m
 Roll period: 14.9 seconds
 Steadiness - As gun platform (Average = 50 %): 85 %
   - Recoil effect (Restricted arc if above 1.00): 0.65
 Seaboat quality  (Average = 1.00): 1.70

Hull form characteristics:
 Hull has a flush deck
 Block coefficient: 0.658
 Length to Beam Ratio: 6.15 : 1
 'Natural speed' for length: 21.91 kts
 Power going to wave formation at top speed: 43 %
 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:  22.00 ft / 6.71 m
    - Forecastle (20 %): 18.00 ft / 5.49 m
    - Mid (50 %):  18.00 ft / 5.49 m
    - Quarterdeck (15 %): 18.00 ft / 5.49 m
    - Stern:  18.00 ft / 5.49 m
    - Average freeboard: 18.32 ft / 5.58 m
 Ship tends to be wet forward

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 111.4 %
  - Above water (accommodation/working, high = better): 129.9 %
 Waterplane Area: 28,899 Square feet or 2,685 Square metres
 Displacement factor (Displacement / loading): 99 %
 Structure weight / hull surface area: 141 lbs/sq ft or 687 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.94
  - Longitudinal: 1.73
  - 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

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