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Tuesday, August 30, 2005

I have a very German-looking drawing of the Ger/CS/1909

In the Fall of 2001, I did a series of German-looking drawings for ship designs from the 1971 building program game. I just did a Springsharp design for the Ger/CS/1909 design that works out pretty well. Springsharp is challenged by destroyer-type ships, and I needed to do two things to make the design work. The main issue was seakeeping ability. To achieve adequate performance, I needed to lighten the machinery by advancing the date and I needed to increase the freeboard by several feet. That was sufficient. I had originally struggled with this ship and had lowered speed and increased the draft abnormally. An odd feature of Springsharp is that it looks at the armament settings for guns in the list that are set to zero and gives warning messages. Here is the Springsharp report:
Ger/CS/1909, Germany Scout Cruiser laid down 1909 (Engine 1941)

Displacement:
 1,574 t light; 1,631 t standard; 1,800 t normal; 1,935 t full load

Dimensions: Length overall / water x beam x draught
 350.45 ft / 350.00 ft x 37.00 ft x 12.00 ft (normal load)
 106.82 m / 106.68 m x 11.28 m  x 3.66 m

Armament:
      4 - 5.00" / 127 mm guns in single mounts, 62.50lbs / 28.35kg shells, 1909 Model
   Quick firing guns in deck mounts with hoists
   on centreline, evenly spread
   Aft Main mounts separated by engine room
 Weight of broadside 250 lbs / 113 kg
 Shells per gun, main battery: 150
 2 - 21.0" / 533.4 mm above water torpedoes

Machinery:
 Oil fired boilers, steam turbines, 
 Direct drive, 2 shafts, 52,349 shp / 39,052 Kw = 35.00 kts
 Range 4,000nm at 15.00 kts
 Bunker at max displacement = 305 tons

Complement:
 137 - 179

Cost:
 £0.221 million / $0.882 million

Distribution of weights at normal displacement:
 Armament: 31 tons, 1.7 %
 Machinery: 994 tons, 55.2 %
 Hull, fittings & equipment: 549 tons, 30.5 %
 Fuel, ammunition & stores: 226 tons, 12.6 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   459 lbs / 208 Kg = 7.3 x 5.0 " / 127 mm shells or 0.3 torpedoes
 Stability (Unstable if below 1.00): 1.47
 Metacentric height 2.2 ft / 0.7 m
 Roll period: 10.5 seconds
 Steadiness - As gun platform (Average = 50 %): 51 %
   - Recoil effect (Restricted arc if above 1.00): 0.27
 Seaboat quality  (Average = 1.00): 1.02

Hull form characteristics:
 Hull has raised forecastle, rise forward of midbreak
 Block coefficient: 0.405
 Length to Beam Ratio: 9.46 : 1
 'Natural speed' for length: 18.71 kts
 Power going to wave formation at top speed: 70 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 1.00 degrees
 Stern overhang: 0.00 ft / 0.00 m
 Freeboard (% = measuring location as a percentage of overall length):
    - Stem:  26.00 ft / 7.92 m
    - Forecastle (20 %): 22.00 ft / 6.71 m (21.00 ft / 6.40 m aft of break)
    - Mid (32 %):  22.00 ft / 6.71 m (14.00 ft / 4.27 m aft of break)
    - Quarterdeck (15 %): 14.00 ft / 4.27 m
    - Stern:  14.00 ft / 4.27 m
    - Average freeboard: 16.82 ft / 5.13 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 191.4 %
  - Above water (accommodation/working, high = better): 152.8 %
 Waterplane Area: 7,997 Square feet or 743 Square metres
 Displacement factor (Displacement / loading): 60 %
 Structure weight / hull surface area: 34 lbs/sq ft or 165 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.44
  - Longitudinal: 2.42
  - Overall: 0.52
 Hull space for machinery, storage, compartmentation is cramped
 Room for accommodation and workspaces is excellent

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