Small Fast Ligth-Destroyer

[ledeper]

Enter ship name, Enter country Enter ship type laid down 1910

Displacement:
   497 t light; 516 t standard; 585 t normal; 640 t full load

Dimensions: Length overall / water x beam x draught
   250,95 ft / 246,06 ft x 26,25 ft x 9,02 ft (normal load)
   76,49 m / 75,00 m x 8,00 m  x 2,75 m

Armament:
      2 - 4,00" / 102 mm guns in single mounts, 32,00lbs / 14,51kg shells, 1910 Model
     Quick firing guns in deck mounts
     on centreline, all forward, 1 raised mount
      2 - 1,57" / 40,0 mm guns in single mounts, 1,95lbs / 0,89kg shells, 1910 Model
     Quick firing guns in deck mounts
     on side, all amidships
   Weight of broadside 68 lbs / 31 kg
   Shells per gun, main battery: 190
   4 - 21,0" / 533,4 mm above water torpedoes

Machinery:
   Oil fired boilers, steam turbines,
   Direct drive, 1 shaft, 11.792 shp / 8.797 Kw = 28,10 kts
   Range 2.000nm at 14,00 kts
   Bunker at max displacement = 123 tons

Complement:
   59 - 77

Cost:
   £0,064 million / $0,256 million

Distribution of weights at normal displacement:
   Armament: 8 tons, 1,5 %
   Machinery: 282 tons, 48,2 %
   Hull, fittings & equipment: 159 tons, 27,2 %
   Fuel, ammunition & stores: 88 tons, 15,0 %
   Miscellaneous weights: 48 tons, 8,2 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     164 lbs / 75 Kg = 5,1 x 4,0 " / 102 mm shells or 0,2 torpedoes
   Stability (Unstable if below 1.00): 1,34
   Metacentric height 1,1 ft / 0,3 m
   Roll period: 10,4 seconds
   Steadiness   - As gun platform (Average = 50 %): 62 %
         - Recoil effect (Restricted arc if above 1.00): 0,14
   Seaboat quality  (Average = 1.00): 1,24

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0,351
   Length to Beam Ratio: 9,38 : 1
   'Natural speed' for length: 15,69 kts
   Power going to wave formation at top speed: 65 %
   Trim (Max stability = 0, Max steadiness = 100): 50
   Bow angle (Positive = bow angles forward): 15,00 degrees
   Stern overhang: 0,00 ft / 0,00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      18,24 ft / 5,56 m
      - Forecastle (20 %):   10,99 ft / 3,35 m
      - Mid (50 %):      10,99 ft / 3,35 m
      - Quarterdeck (15 %):   10,99 ft / 3,35 m
      - Stern:      10,99 ft / 3,35 m
      - Average freeboard:   11,57 ft / 3,53 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 175,8 %
      - Above water (accommodation/working, high = better): 75,2 %
   Waterplane Area: 3.695 Square feet or 343 Square metres
   Displacement factor (Displacement / loading): 54 %
   Structure weight / hull surface area: 21 lbs/sq ft or 101 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0,43
      - Longitudinal: 2,21
      - Overall: 0,50
   Hull space for machinery, storage, compartmentation is cramped
   Room for accommodation and workspaces is cramped
   Good seaboat, rides out heavy weather easily

[Ithekro]

The cross-sectional is too low and the Block Coefficient is too low (by most standards).  Makes for a fine light destroyer though.  I had similar problems simming historical Chilean destroyers from 1900.  Their listed figures place them with a Block Coefficient that is far too low and messes up several other factors.  The only reason I kept them was because they were what Chile had for real.

[maddox]

http://www.navalism.org/index.php?topic=327.0

1 - Destroyers have a minimal overall and cross-sectional strength of 0.50 - this is to represent lightweight destroyer machinery, as realistic speeds cannot be met with keeping composite strength to 1.00.  For ships of composite strength below 1.00, we as mods reserve the right to deal out damage or even loss in heavy weather.

[The Rock Doctor]

A length to beam ratio of around 10.5:1 to 11:1, with a BC of .4, ought to work, I'd think.