Amazon Ad

Friday, September 28, 2007

An alternative Ger/CM/1914 design

There is a sketch of the largest ship in the family of specifications for fast German minelayers. That ship is flush-decked. That inspired me to try a flush-decked alternative to what I last wrote about. This would be a Ger/CM/1914 that tries to have a more typical draft, or at least not an oddly deep draft. That is the main difference. The ship might well not have had the mines on the upper deck, but I kept them there. The Germans only used 5in guns in my alternate universe, of course. This is at least a more rational design, in my opinion, although not quite as fast:
Ger/CM/1914, Germany Cruiser Minelayer laid down 1914 (Engine 1950)

Displacement:
 3,323 t light; 3,414 t standard; 3,733 t normal; 3,989 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
 (437.95 ft / 435.00 ft) x 38.00 ft x (17.00 / 17.81 ft)
 (133.49 m / 132.59 m) x 11.58 m  x (5.18 / 5.43 m)

Armament:
      3 - 5.00" / 127 mm 45.0 cal guns - 65.00lbs / 29.48kg shells, 150 per gun
   Quick firing guns in deck and hoist mounts, 1914 Model
   1 x Single mount on centreline forward
   1 x Single mount on centreline, aft deck forward
      Weight of broadside 195 lbs / 88 kg

Armour:
   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 3.00" / 76 mm 2.00" / 51 mm  3.00" / 76 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 2 shafts, 99,257 shp / 74,046 Kw = 39.00 kts
 Range 4,800nm at 15.00 kts
 Bunker at max displacement = 575 tons

Complement:
 238 - 310

Cost:
 £0.562 million / $2.248 million

Distribution of weights at normal displacement:
 Armament: 51 tons, 1.4 %
 Armour: 31 tons, 0.8 %
    - Armament: 31 tons, 0.8 %
 Machinery: 2,195 tons, 58.8 %
 Hull, fittings & equipment: 908 tons, 24.3 %
 Fuel, ammunition & stores: 411 tons, 11.0 %
 Miscellaneous weights: 138 tons, 3.7 %
    - On freeboard deck: 138 tons

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   740 lbs / 335 Kg = 11.8 x 5.0 " / 127 mm shells or 0.3 torpedoes
 Stability (Unstable if below 1.00): 1.21
 Metacentric height 1.7 ft / 0.5 m
 Roll period: 12.4 seconds
 Steadiness - As gun platform (Average = 50 %): 60 %
   - Recoil effect (Restricted arc if above 1.00): 0.25
 Seaboat quality  (Average = 1.00): 1.10

Hull form characteristics:
 Hull has a flush deck,
   a normal bow and large transom stern
 Block coefficient (normal/deep): 0.465 / 0.474
 Length to Beam Ratio: 11.45 : 1
 'Natural speed' for length: 23.66 kts
 Power going to wave formation at top speed: 70 %
 Trim (Max stability = 0, Max steadiness = 100): 55
 Bow angle (Positive = bow angles forward): 7.00 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 %,  24.00 ft / 7.32 m,  22.00 ft / 6.71 m
    - Forward deck: 25.00 %,  22.00 ft / 6.71 m,  20.00 ft / 6.10 m
    - Aft deck: 40.00 %,  20.00 ft / 6.10 m,  18.00 ft / 5.49 m
    - Quarter deck: 15.00 %,  18.00 ft / 5.49 m,  18.00 ft / 5.49 m
    - Average freeboard:  20.11 ft / 6.13 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 194.2 %
  - Above water (accommodation/working, high = better): 175.5 %
 Waterplane Area: 11,095 Square feet or 1,031 Square metres
 Displacement factor (Displacement / loading): 73 %
 Structure weight / hull surface area: 36 lbs/sq ft or 173 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.42
  - Longitudinal: 2.56
  - Overall: 0.51
 Hull space for machinery, storage, compartmentation is cramped
 Room for accommodation and workspaces is excellent

No comments:

Amazon Context Links