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Monday, July 30, 2007

An attempt at William Hovgaard's "Battleship-Cruiser" in 1903

I wanted to see what could be done with using 1903 technology to implement William Hovgaard's Battleship-Cruiser concept. He wanted a fast battleship that might sacrifice a few guns to still have heavy armour and a high speed. I was able to have 8-12in/45, 12-6in QF guns, an 10in belt, and 24 knots speed. To do that with reciprocating engines and coal-fired boilers demands a very large ship. My Springsharp design is 25,911 tons standard. This is the Springsharp report:
GB/BB/1903, Great Britain Battleship-Cruiser laid down 1903

Displacement:
 24,902 t light; 25,911 t standard; 28,487 t normal; 30,547 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
 (593.00 ft / 585.00 ft) x 90.00 ft x (29.00 / 30.78 ft)
 (180.75 m / 178.31 m) x 27.43 m  x (8.84 / 9.38 m)

Armament:
      8 - 12.00" / 305 mm 45.0 cal guns - 850.00lbs / 385.55kg shells, 90 per gun
   Breech loading guns in turret on barbette mounts, 1903 Model
   2 x Twin mounts on centreline ends, evenly spread
   2 x Twin mounts on sides, forward deck aft
      12 - 6.00" / 152 mm 45.0 cal guns - 100.00lbs / 45.36kg shells, 150 per gun
   Quick firing guns in casemate mounts, 1903 Model
   6 x Single mounts on sides, forward deck aft
   6 x Single mounts on sides, aft deck forward
      Weight of broadside 8,000 lbs / 3,629 kg

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 10.0" / 254 mm 380.00 ft / 115.82 m 8.00 ft / 2.44 m
 Ends: 4.00" / 102 mm 120.00 ft / 36.58 m 12.00 ft / 3.66 m
   85.00 ft / 25.91 m Unarmoured ends
 Upper: 7.00" / 178 mm 380.00 ft / 115.82 m 8.00 ft / 2.44 m
   Main Belt covers 100 % of normal length
   Main belt does not fully cover magazines and engineering spaces

   - Torpedo Bulkhead:
  1.00" / 25 mm 380.00 ft / 115.82 m 26.00 ft / 7.92 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 10.0" / 254 mm 7.00" / 178 mm  10.0" / 254 mm
 2nd: 5.00" / 127 mm 4.00" / 102 mm  5.00" / 127 mm

   - Protected deck - single deck: 3.00" / 76 mm For and Aft decks
 Forecastle: 3.00" / 76 mm  Quarter deck: 3.00" / 76 mm

   - Conning towers: Forward 10.00" / 254 mm,  Aft 0.00" / 0 mm

Machinery:
 Coal fired boilers, complex reciprocating steam engines, 
 Direct drive, 4 shafts, 57,734 ihp / 43,070 Kw = 24.00 kts
 Range 4,800nm at 14.00 kts
 Bunker at max displacement = 4,635 tons (100% coal)

Complement:
 1,096 - 1,425

Cost:
 £2.790 million / $11.162 million

Distribution of weights at normal displacement:
 Armament: 1,462 tons, 5.1 %
 Armour: 7,044 tons, 24.7 %
    - Belts: 2,480 tons, 8.7 %
    - Torpedo bulkhead: 366 tons, 1.3 %
    - Armament: 1,736 tons, 6.1 %
    - Armour Deck: 2,261 tons, 7.9 %
    - Conning Tower: 201 tons, 0.7 %
 Machinery: 8,617 tons, 30.2 %
 Hull, fittings & equipment: 7,779 tons, 27.3 %
 Fuel, ammunition & stores: 3,585 tons, 12.6 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   19,976 lbs / 9,061 Kg = 23.1 x 12.0 " / 305 mm shells or 2.5 torpedoes
 Stability (Unstable if below 1.00): 1.22
 Metacentric height 6.2 ft / 1.9 m
 Roll period: 15.2 seconds
 Steadiness - As gun platform (Average = 50 %): 96 %
   - Recoil effect (Restricted arc if above 1.00): 0.52
 Seaboat quality  (Average = 1.00): 1.35

Hull form characteristics:
 Hull has rise forward of midbreak,
   a ram bow and a cruiser stern
 Block coefficient (normal/deep): 0.653 / 0.660
 Length to Beam Ratio: 6.50 : 1
 'Natural speed' for length: 24.19 kts
 Power going to wave formation at top speed: 52 %
 Trim (Max stability = 0, Max steadiness = 100): 71
 Bow angle (Positive = bow angles forward): -3.00 degrees
 Stern overhang: -3.00 ft / -0.91 m
 Freeboard (% = length of deck as a percentage of waterline length):
    Fore end,  Aft end
    - Forecastle: 30.00 %,  24.00 ft / 7.32 m,  24.00 ft / 7.32 m
    - Forward deck: 33.00 %,  24.00 ft / 7.32 m,  24.00 ft / 7.32 m
    - Aft deck: 22.00 %,  16.00 ft / 4.88 m,  16.00 ft / 4.88 m
    - Quarter deck: 15.00 %,  16.00 ft / 4.88 m,  16.00 ft / 4.88 m
    - Average freeboard:  21.04 ft / 6.41 m
 Ship tends to be wet forward

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 155.0 %
  - Above water (accommodation/working, high = better): 146.2 %
 Waterplane Area: 40,444 Square feet or 3,757 Square metres
 Displacement factor (Displacement / loading): 92 %
 Structure weight / hull surface area: 147 lbs/sq ft or 715 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.96
  - Longitudinal: 1.45
  - 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
 Good seaboat, rides out heavy weather easily

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