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Saturday, June 18, 2005

We did a design study, in 1971, for a 13.5in gun version of Cliff's fast batteship concep

Following the lead of what my friend Cliff had done with battleships with 6-12in guns, we did a design study for a battleship with 6-13.5in guns. The original specification was for a normal displacement of 29,000 tons, a prismatic coefficient of 0.59 and a midship coefficient of 0.97. The dimensions were 620ft x 95ft x 30.2ft. The armament was 6-13.5in/45 guns. I think that we were contemplating only having 40,000 SHP machinery. The weight budget looked like this:
  • Machinery: 2,900 tons
  • Protection: 10,496 tons
  • Hull: 12,180 tons
  • Armament: 1,104 tons
  • Miscellaneous: 2,320 tons
I found that in Springsharp, more could be achieved at this date (circa 1909). I moved our hull weight surplus into machinery for a 27 knot speed. This is the Springsharp report:
GB/BB/1909 13.5in Sketch Design, Great Britain Battleship laid down 1909

Displacement:
 24,898 t light; 25,899 t standard; 29,070 t normal; 31,607 t full load

Dimensions: Length overall / water x beam x draught
 620.00 ft / 620.00 ft x 95.00 ft x 30.20 ft (normal load)
 188.98 m / 188.98 m x 28.96 m  x 9.20 m

Armament:
      6 - 13.50" / 343 mm guns (3x2 guns), 1,230.19lbs / 558.00kg shells, 1909 Model
   Breech loading guns in turrets (on barbettes)
   on centreline ends, majority forward, 1 raised mount - superfiring
      8 - 6.00" / 152 mm guns (4x2 guns), 108.00lbs / 48.99kg shells, 1909 Model
   Quick firing guns in turrets (on barbettes)
   on side, all amidships
 Weight of broadside 8,245 lbs / 3,740 kg
 Shells per gun, main battery: 90

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 14.0" / 356 mm 405.00 ft / 123.44 m 17.00 ft / 5.18 m
 Ends: Unarmoured
   Main Belt covers 100 % of normal length

   - Torpedo Bulkhead:
  2.00" / 51 mm 405.00 ft / 123.44 m 28.00 ft / 8.53 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 14.0" / 356 mm 9.00" / 229 mm  14.0" / 356 mm
 2nd: 6.00" / 152 mm 4.00" / 102 mm  6.00" / 152 mm

   - Armour deck: 4.00" / 102 mm, Conning tower: 14.00" / 356 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Direct drive, 4 shafts, 88,454 shp / 65,987 Kw = 27.00 kts
 Range 7,500nm at 15.00 kts
 Bunker at max displacement = 5,709 tons

Complement:
 1,113 - 1,447

Cost:
 £2.300 million / $9.200 million

Distribution of weights at normal displacement:
 Armament: 1,031 tons, 3.5 %
 Armour: 10,461 tons, 36.0 %
    - Belts: 4,196 tons, 14.4 %
    - Torpedo bulkhead: 839 tons, 2.9 %
    - Armament: 2,035 tons, 7.0 %
    - Armour Deck: 3,105 tons, 10.7 %
    - Conning Tower: 285 tons, 1.0 %
 Machinery: 4,021 tons, 13.8 %
 Hull, fittings & equipment: 9,386 tons, 32.3 %
 Fuel, ammunition & stores: 4,172 tons, 14.4 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   37,244 lbs / 16,894 Kg = 30.3 x 13.5 " / 343 mm shells or 6.2 torpedoes
 Stability (Unstable if below 1.00): 1.19
 Metacentric height 6.4 ft / 1.9 m
 Roll period: 15.8 seconds
 Steadiness - As gun platform (Average = 50 %): 56 %
   - Recoil effect (Restricted arc if above 1.00): 0.32
 Seaboat quality  (Average = 1.00): 1.12

Hull form characteristics:
 Hull has raised forecastle, rise forward of midbreak
 Block coefficient: 0.572
 Length to Beam Ratio: 6.53 : 1
 'Natural speed' for length: 24.90 kts
 Power going to wave formation at top speed: 55 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 0.00 degrees
 Stern overhang: 0.00 ft / 0.00 m
 Freeboard (% = measuring location as a percentage of overall length):
    - Stem:  32.00 ft / 9.75 m
    - Forecastle (20 %): 30.00 ft / 9.14 m (0.00 ft / 0.00 m aft of break)
    - Mid (67 %):  30.00 ft / 9.14 m (22.00 ft / 6.71 m aft of break)
    - Quarterdeck (15 %): 22.00 ft / 6.71 m
    - Stern:  22.00 ft / 6.71 m
    - Average freeboard: 20.47 ft / 6.24 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 91.1 %
  - Above water (accommodation/working, high = better): 121.6 %
 Waterplane Area: 41,963 Square feet or 3,898 Square metres
 Displacement factor (Displacement / loading): 109 %
 Structure weight / hull surface area: 158 lbs/sq ft or 773 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.95
  - Longitudinal: 1.50
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is adequate
 Room for accommodation and workspaces is excellent

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