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Saturday, June 02, 2007

The Ger/DL/1915 design

The Ger/DL/1915 design is less capable than I had hoped. I think that I had visions of a 35knot speed or better. These were the original specifications:
Ger/DL/1915  332ft x 32ft   5-5in guns and 4-23.6in TT
   Displacement of 1,800 tons  Cp=0.60  Cm=0.80  draft=12.7ft
Fuel 450 tons  displacement of 2,250 tons full load
Power output=20SHP/ton of displacement   45,000 SHP with 50SHP/ton machinery
Weights  900 tons machinery   fuel consumption 12.1 tons per hour for 37.4 hours

This is the Springsharp report:
Ger/DL/1915, Germany Destroyer Leader laid down 1950

Displacement:
 1,293 t light; 1,352 t standard; 1,606 t normal; 1,809 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
 (334.70 ft / 332.00 ft) x 32.00 ft x (13.00 / 14.08 ft)
 (102.02 m / 101.19 m) x 9.75 m  x (3.96 / 4.29 m)

Armament:
      5 - 5.00" / 127 mm 50.0 cal guns - 66.16lbs / 30.01kg shells, 150 per gun
   Quick firing guns in deck and hoist mounts , 1950 Model
   4 x Single mounts on centreline ends, majority forward
   1 x Single mount on centreline, forward deck aft
 Weight of broadside 331 lbs / 331 kg
 4 - 23.6" / 599 mm above water torpedoes

Armour:
   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 1.00" / 25 mm 1.00" / 25 mm  1.00" / 25 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 2 shafts, 38,438 shp / 28,675 Kw = 33.00 kts
 Range 6,000nm at 16.00 kts
 Bunker at max displacement = 457 tons

Complement:
 126 - 164

Cost:
 £1.439 million / $5.754 million

Distribution of weights at normal displacement:
 Armament: 99 tons, 6.2 %
 Armour: 35 tons, 2.2 %
    - Belts: 0 tons, 0.0 %
    - Torpedo bulkhead: 0 tons, 0.0 %
    - Armament: 35 tons, 2.2 %
    - Armour Deck: 0 tons, 0.0 %
    - Conning Tower: 0 tons, 0.0 %
 Machinery: 741 tons, 46.1 %
 Hull, fittings & equipment: 475 tons, 29.6 %
 Fuel, ammunition & stores: 313 tons, 19.5 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   435 lbs / 198 Kg = 7.0 x 5.0 " / 127 mm shells or 0.3 torpedoes
 Stability (Unstable if below 1.00): 1.20
 Metacentric height 1.3 ft / 0.4 m
 Roll period: 12.0 seconds
 Steadiness - As gun platform (Average = 50 %): 54 %
   - Recoil effect (Restricted arc if above 1.00): 0.64
 Seaboat quality  (Average = 1.00): 1.01

Hull form characteristics:
 Hull has rise forward of midbreak,
   a normal bow and a round stern
 Block coefficient (normal/deep): 0.407 / 0.423
 Length to Beam Ratio: 10.38 : 1
 'Natural speed' for length: 18.22 kts
 Power going to wave formation at top speed: 67 %
 Trim (Max stability = 0, Max steadiness = 100): 53
 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: 18.00 %,  22.00 ft / 6.71 m,  20.00 ft / 6.10 m
    - Forward deck: 15.00 %,  20.00 ft / 6.10 m,  20.00 ft / 6.10 m
    - Aft deck: 52.00 %,  12.00 ft / 3.66 m,  12.00 ft / 3.66 m
    - Quarter deck: 15.00 %,  12.00 ft / 3.66 m,  12.00 ft / 3.66 m
    - Average freeboard:  14.78 ft / 4.51 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 168.9 %
  - Above water (accommodation/working, high = better): 92.0 %
 Waterplane Area: 6,567 Square feet or 610 Square metres
 Displacement factor (Displacement / loading): 73 %
 Structure weight / hull surface area: 33 lbs/sq ft or 163 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.46
  - Longitudinal: 2.20
  - Overall: 0.54
 Hull space for machinery, storage, compartmentation is cramped
 Room for accommodation and workspaces is adequate

2 comments:

eltf177 said...

Question: the Ger/DL/1915 is obviously a 1915 design, yet you have a laydown date of 19150 listed. Was that supposed to be the engine date?

Jim said...

Yes, I should have made the laydown date 1915 and the engine date 1950, to get the needed SHP/ton machinery weight. I justify that on the fact that the British Swift achieved 60 SHP/ton about 1908. I am asking for less than that. In this version, the machinery can produce 51.87 SHP/ton of machinery weight.

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