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Friday, May 27, 2005

I just redid the GB/CB/1905 with what I learned today (Updated)

I just tried my friend Cliff's design for the GB/CB/1905 fast battlecruiser, without raised gun mounts. I hadn't realized that the "above freeboard" number was for indicating raised guns. It turns out that is apparently how you are suposed to designate superfiring guns. You probably don't know about the GB/CB/1905 design, which I have written about repeatedly, and have my original drawings at Kentishknock.com. The armament is 4-12in/45 guns and 9-6in guns. The design has a 4in belt with a 2.5in deck, as presently defined. The A/T bulkhead is 1.5in. The result is very close to Cliff's original concept. My only fudge is raising the SHP/ton for the machinery above what SpringSharp is willing to concede for 1905. Well, my other fudge is to use oil fuel, but that was Cliff and my decision for our ships: to use only oil fuel. I also believe that a higher SHP/ton was achievable in 1905. The British were simply not prepared to accept the higher SHP/ton for large ships, because they opted for reliability rather than performance. They could do more, as the Swift could produce 60 SHP/ton from a plant designed in 1905-1906. I updated the design lengthen the belt to cover the machinery spaces completely. This is the SpringSharp report:
GB/CB/1905, Great Britain Battlecruiser laid down 1905 (Engine 1912)

Displacement:
 22,095 t light; 22,830 t standard; 25,400 t normal; 27,456 t full load

Dimensions: Length overall / water x beam x draught
 770.00 ft / 770.00 ft x 85.00 ft x 27.00 ft (normal load)
 234.70 m / 234.70 m x 25.91 m  x 8.23 m

Armament:
      4 - 12.00" / 305 mm guns (2x2 guns), 850.00lbs / 385.55kg shells, 1905 Model
   Breech loading guns in turrets (on barbettes)
   on centreline ends, evenly spread
      4 - 6.00" / 152 mm guns in single mounts, 108.00lbs / 48.99kg shells, 1905 Model
   Quick firing guns in deck mounts with hoists
   on side, all forward
      5 - 6.00" / 152 mm guns in single mounts, 108.00lbs / 48.99kg shells, 1905 Model
   Quick firing guns in deck mounts with hoists
   on side, all aft
 Weight of broadside 4,372 lbs / 1,983 kg
 Shells per gun, main battery: 90

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 4.00" / 102 mm 650.00 ft / 198.12 m 18.00 ft / 5.49 m
 Ends: Unarmoured
   Main Belt covers 130 % of normal length

   - Torpedo Bulkhead:
  1.50" / 38 mm 650.00 ft / 198.12 m 26.00 ft / 7.92 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 9.00" / 229 mm 6.00" / 152 mm  9.00" / 229 mm
 2nd: 2.00" / 51 mm       -         -

   - Armour deck: 2.50" / 64 mm, Conning tower: 9.00" / 229 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Direct drive, 4 shafts, 155,302 shp / 115,855 Kw = 33.00 kts
 Range 7,500nm at 15.00 kts
 Bunker at max displacement = 4,626 tons

Complement:
 1,005 - 1,307

Cost:
 £2.105 million / $8.421 million

Distribution of weights at normal displacement:
 Armament: 554 tons, 2.2 %
 Armour: 5,821 tons, 22.9 %
    - Belts: 1,882 tons, 7.4 %
    - Torpedo bulkhead: 938 tons, 3.7 %
    - Armament: 811 tons, 3.2 %
    - Armour Deck: 2,023 tons, 8.0 %
    - Conning Tower: 168 tons, 0.7 %
 Machinery: 6,192 tons, 24.4 %
 Hull, fittings & equipment: 9,528 tons, 37.5 %
 Fuel, ammunition & stores: 3,305 tons, 13.0 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   33,592 lbs / 15,237 Kg = 38.9 x 12.0 " / 305 mm shells or 4.1 torpedoes
 Stability (Unstable if below 1.00): 1.31
 Metacentric height 6.4 ft / 1.9 m
 Roll period: 14.2 seconds
 Steadiness - As gun platform (Average = 50 %): 66 %
   - Recoil effect (Restricted arc if above 1.00): 0.32
 Seaboat quality  (Average = 1.00): 1.31

Hull form characteristics:
 Hull has rise forward of midbreak
 Block coefficient: 0.503
 Length to Beam Ratio: 9.06 : 1
 'Natural speed' for length: 27.75 kts
 Power going to wave formation at top speed: 53 %
 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:  31.00 ft / 9.45 m
    - Forecastle (20 %): 27.00 ft / 8.23 m
    - Mid (67 %):  27.00 ft / 8.23 m (19.00 ft / 5.79 m aft of break)
    - Quarterdeck (15 %): 19.00 ft / 5.79 m
    - Stern:  19.00 ft / 5.79 m
    - Average freeboard: 24.68 ft / 7.52 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 125.2 %
  - Above water (accommodation/working, high = better): 205.4 %
 Waterplane Area: 43,730 Square feet or 4,063 Square metres
 Displacement factor (Displacement / loading): 112 %
 Structure weight / hull surface area: 142 lbs/sq ft or 695 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.97
  - Longitudinal: 1.27
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is cramped
 Room for accommodation and workspaces is excellent
 Good seaboat, rides out heavy weather easily

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