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Sunday, February 11, 2007

A revised GB/CB/1905 battlecruiser done with Springsharp 3.0 Beta

I have revised my GB/CB/1905 design, done with Springsharp 3.0 Beta. I am getting somewhat better at using the program and had also decided to use coal-fired boilers, as that is more usual for 1905. The ship can still make 33 knots, with lighter weight machinery. I am still getting a Springsharp error that I do not understand. As you just saw, this is the photograph of one of the ships:

I lowered the freeboard by a foot, since there is plenty of seakeeping ability. This is the new Springsharp 3.0 freeboard display. I did that to save weight. I also lowered the maximum speed to the originally designed 33 knots. I fixed the bow type to be a ram. I had wondered why I was not able set that as an option. This is the Springsharp report:
GB/CB/1905, Great Britain Battlecruiser laid down 1905 (Engine 1909)

Displacement:
 24,223 t light; 25,054 t standard; 28,729 t normal; 31,669 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
 (778.00 ft / 770.00 ft) x 85.00 ft x (27.00 / 29.21 ft)
 (237.13 m / 234.70 m) x 25.91 m  x (8.23 / 8.90 m)

Armament:
      4 - 12.00" / 305 mm 45.0 cal guns - 871.37lbs / 395.24kg shells, 90 per gun
   Breech loading guns in turret on barbette mounts , 1905 Model
   2 x Single mounts on centreline ends, evenly spread
      9 - 6.00" / 152 mm 45.0 cal guns - 108.92lbs / 49.41kg shells, 150 per gun
   Breech loading guns in deck mounts , 1905 Model
   1 x Single mount on centreline, aft evenly spread
   8 x Single mounts on sides, evenly spread
 Weight of broadside 4,466 lbs / 4,466 kg

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 4.00" / 102 mm 540.00 ft / 164.59 m 16.00 ft / 4.88 m
 Ends: Unarmoured
   Main Belt covers 108 % of normal length
   Main belt does not fully cover magazines and engineering spaces

   - Torpedo Bulkhead:
  2.00" / 51 mm 540.00 ft / 164.59 m 27.00 ft / 8.23 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 8.00" / 203 mm 6.00" / 152 mm  8.00" / 203 mm

   - Armour deck: 2.00" / 51 mm, Conning tower: 8.00" / 203 mm

Machinery:
 Coal fired boilers, steam turbines, 
 ERROR: Revise drives, 4 shafts, 172,585 shp / 128,748 Kw = 33.00 kts
 Range 6,200nm at 15.00 kts
 Bunker at max displacement = 6,615 tons (100% coal)

Complement:
 1,103 - 1,434

Cost:
 £2.428 million / $9.710 million

Distribution of weights at normal displacement:
 Armament: 908 tons, 3.2 %
 Armour: 5,190 tons, 18.1 %
    - Belts: 1,438 tons, 5.0 %
    - Torpedo bulkhead: 1,079 tons, 3.8 %
    - Armament: 791 tons, 2.8 %
    - Armour Deck: 1,720 tons, 6.0 %
    - Conning Tower: 162 tons, 0.6 %
 Machinery: 8,629 tons, 30.0 %
 Hull, fittings & equipment: 9,962 tons, 34.7 %
 Fuel, ammunition & stores: 4,505 tons, 15.7 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   31,789 lbs / 14,419 Kg = 36.8 x 12.0 " / 305 mm shells or 3.6 torpedoes
 Stability (Unstable if below 1.00): 1.39
 Metacentric height 7.0 ft / 2.1 m
 Roll period: 13.5 seconds
 Steadiness - As gun platform (Average = 50 %): 62 %
   - Recoil effect (Restricted arc if above 1.00): 0.30
 Seaboat quality  (Average = 1.00): 1.25

Hull form characteristics:
 Hull has low quarterdeck ,
   a ram bow and a cruiser stern
 Block coefficient (normal/deep): 0.569 / 0.580
 Length to Beam Ratio: 9.06 : 1
 'Natural speed' for length: 27.75 kts
 Power going to wave formation at top speed: 55 %
 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 (% = length of deck as a percentage of waterline length):
    Fore end,  Aft end
    - Forecastle: 30.00 %,  31.00 ft / 9.45 m,  27.00 ft / 8.23 m
    - Forward deck: 34.00 %,  27.00 ft / 8.23 m,  27.00 ft / 8.23 m
    - Aft deck: 3.00 %,  27.00 ft / 8.23 m,  27.00 ft / 8.23 m
    - Quarter deck: 33.00 %,  19.00 ft / 5.79 m,  21.00 ft / 6.40 m
    - Average freeboard:  25.17 ft / 7.67 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 143.1 %
  - Above water (accommodation/working, high = better): 216.8 %
 Waterplane Area: 46,499 Square feet or 4,320 Square metres
 Displacement factor (Displacement / loading): 111 %
 Structure weight / hull surface area: 141 lbs/sq ft or 690 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.98
  - Longitudinal: 1.22
  - 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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