Amazon Ad

Wednesday, March 28, 2007

Near the limits of what is possible: a 40-knot GB/CB/1905

This is probably not a desirable thing to do, but I had wondered what was possible with the GB/CB/1905 design. It may be that by increasing the freeboard, I might have gotten another knot or two from the ship, but settled for 40 knots. I implemented various weight-saving measures and went to six shafts. Six shafts on a ship with an 85ft beam is not very practical, to say the least. The power plant must use the lightest machinery possible, and really, this is an anachronistic design, as it seems necessary to use geared turbines before their time, to satisfy Springsharp 3.0b1 Beta. Yesterday's design is probably more like what is practically achievable with acceptable protection (if you don't mind a 4in belt, at least). This is an older photo of a ship of the class:

By clicking on the image, you can pop the larger version of the photo. This is the Springsharp report:
GB/CB/1905 very extreme, Great Britain Battlecruiser laid down 1905 (Engine 1950)

Displacement:
 21,902 t light; 22,620 t standard; 23,667 t normal; 24,504 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
 (778.00 ft / 770.00 ft) x 85.00 ft x (28.00 / 28.70 ft)
 (237.13 m / 234.70 m) x 25.91 m  x (8.53 / 8.75 m)

Armament:
      4 - 12.00" / 305 mm 45.0 cal guns - 850.00lbs / 385.55kg shells, 90 per gun
   Breech loading guns in turret on barbette mounts , 1905 Model
   2 x Twin mounts on centreline ends, evenly spread
      9 - 6.00" / 152 mm 50.0 cal guns - 100.00lbs / 45.36kg shells, 150 per gun
   Quick firing guns in deck and hoist mounts , 1905 Model
   8 x Single mounts on sides, evenly spread
   1 x Single mount on centreline, aft evenly spread
 Weight of broadside 4,300 lbs / 4,300 kg

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 4.00" / 102 mm 410.00 ft / 124.97 m 12.00 ft / 3.66 m
 Ends: Unarmoured
   Main Belt covers 82 % of normal length
   Main belt does not fully cover magazines and engineering spaces

   - Torpedo Bulkhead:
  1.00" / 25 mm 410.00 ft / 124.97 m 28.00 ft / 8.53 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 4.00" / 102 mm 3.00" / 76 mm  4.00" / 102 mm
 2nd: 3.00" / 76 mm 1.00" / 25 mm  3.00" / 76 mm

   - Armour deck: 2.00" / 51 mm, Conning tower: 4.00" / 102 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 6 shafts, 316,443 shp / 236,066 Kw = 40.00 kts
 Range 5,400nm at 15.00 kts
 Bunker at max displacement = 1,883 tons

Complement:
 953 - 1,240

Cost:
 £2.260 million / $9.039 million

Distribution of weights at normal displacement:
 Armament: 923 tons, 3.9 %
 Armour: 3,389 tons, 14.3 %
    - Belts: 854 tons, 3.6 %
    - Torpedo bulkhead: 425 tons, 1.8 %
    - Armament: 492 tons, 2.1 %
    - Armour Deck: 1,547 tons, 6.5 %
    - Conning Tower: 71 tons, 0.3 %
 Machinery: 7,570 tons, 32.0 %
 Hull, fittings & equipment: 10,427 tons, 44.1 %
 Fuel, ammunition & stores: 1,765 tons, 7.5 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   22,968 lbs / 10,418 Kg = 26.6 x 12.0 " / 305 mm shells or 2.6 torpedoes
 Stability (Unstable if below 1.00): 1.21
 Metacentric height 5.6 ft / 1.7 m
 Roll period: 15.1 seconds
 Steadiness - As gun platform (Average = 50 %): 53 %
   - Recoil effect (Restricted arc if above 1.00): 0.39
 Seaboat quality  (Average = 1.00): 1.01

Hull form characteristics:
 Hull has low quarterdeck ,
   a ram bow and a cruiser stern
 Block coefficient (normal/deep): 0.452 / 0.457
 Length to Beam Ratio: 9.06 : 1
 'Natural speed' for length: 27.75 kts
 Power going to wave formation at top speed: 61 %
 Trim (Max stability = 0, Max steadiness = 100): 52
 Bow angle (Positive = bow angles forward): -2.00 degrees
 Stern overhang: 0.00 ft / 0.00 m
 Freeboard (% = length of deck as a percentage of waterline length):
    Fore end,  Aft end
    - Forecastle: 20.00 %,  34.00 ft / 10.36 m,  32.00 ft / 9.75 m
    - Forward deck: 30.00 %,  32.00 ft / 9.75 m,  30.00 ft / 9.14 m
    - Aft deck: 20.00 %,  30.00 ft / 9.14 m,  30.00 ft / 9.14 m
    - Quarter deck: 30.00 %,  22.00 ft / 6.71 m,  23.00 ft / 7.01 m
    - Average freeboard:  28.61 ft / 8.72 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 157.1 %
  - Above water (accommodation/working, high = better): 255.8 %
 Waterplane Area: 41,817 Square feet or 3,885 Square metres
 Displacement factor (Displacement / loading): 104 %
 Structure weight / hull surface area: 153 lbs/sq ft or 748 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.94
  - Longitudinal: 1.80
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is cramped
 Room for accommodation and workspaces is excellent

No comments:

Amazon Context Links