The GB/DD/1918 design

I had thought that the machinery is too heavy for the power produced, but I was reluctant to make the date any later than 10 years more than the laid-down date. The machinery is 50 SHP/ton, so it is not that bad. I also wondered if the problem was that power to reach 35 knots is greater than would really be needed. I looked at some example ships. The A-class ships had 505 ton machinery that produced 34,000 SHP. The improvements in the GB/DD/1918 design include a 35 knot speed, a 4,200nm range at 12 knots, 8-21in TT, and 4-2pdr AA. This is the Springsharp report:

GB/DD/1918, Great Britain Destroyer laid down 1918 (Engine 1928)

Displacement:
 1,199 t light; 1,251 t standard; 1,350 t normal; 1,429 t full load

Dimensions: Length overall / water x beam x draught
 326.21 ft / 325.00 ft x 31.00 ft x 12.00 ft (normal load)
 99.43 m / 99.06 m x 9.45 m  x 3.66 m

Armament:
      4 - 4.70" / 119 mm guns in single mounts, 51.91lbs / 23.55kg shells, 1918 Model
   Quick firing guns in deck mounts with hoists
   on centreline ends, evenly spread, 2 raised mounts - superfiring
      4 - 1.57" / 40.0 mm guns (1x4 guns), 2.00lbs / 0.91kg shells, 1918 Model
   Anti-aircraft guns in deck mount 
   on side amidships, all raised guns
 Weight of broadside 216 lbs / 98 kg
 Shells per gun, main battery: 200
 8 - 21.0" / 533.4 mm above water torpedoes

Machinery:
 Oil fired boilers, steam turbines, 
 Direct drive, 2 shafts, 36,622 shp / 27,320 Kw = 35.00 kts
 Range 4,200nm at 12.00 kts
 Bunker at max displacement = 178 tons

Complement:
 110 - 144

Cost:
 £0.333 million / $1.332 million

Distribution of weights at normal displacement:
 Armament: 27 tons, 2.0 %
 Machinery: 728 tons, 53.9 %
 Hull, fittings & equipment: 444 tons, 32.9 %
 Fuel, ammunition & stores: 151 tons, 11.2 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   333 lbs / 151 Kg = 6.4 x 4.7 " / 119 mm shells or 0.2 torpedoes
 Stability (Unstable if below 1.00): 1.28
 Metacentric height 1.3 ft / 0.4 m
 Roll period: 11.2 seconds
 Steadiness - As gun platform (Average = 50 %): 55 %
   - Recoil effect (Restricted arc if above 1.00): 0.56
 Seaboat quality  (Average = 1.00): 1.11

Hull form characteristics:
 Hull has rise forward of midbreak
   and transom stern
 Block coefficient: 0.391
 Length to Beam Ratio: 10.48 : 1
 'Natural speed' for length: 20.80 kts
 Power going to wave formation at top speed: 70 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 3.00 degrees
 Stern overhang: 0.00 ft / 0.00 m
 Freeboard (% = measuring location as a percentage of overall length):
    - Stem:  23.00 ft / 7.01 m
    - Forecastle (20 %): 21.00 ft / 6.40 m
    - Mid (35 %):  21.00 ft / 6.40 m (13.00 ft / 3.96 m aft of break)
    - Quarterdeck (15 %): 13.00 ft / 3.96 m
    - Stern:  13.00 ft / 3.96 m
    - Average freeboard: 15.96 ft / 4.86 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 189.8 %
  - Above water (accommodation/working, high = better): 74.6 %
 Waterplane Area: 6,404 Square feet or 595 Square metres
 Displacement factor (Displacement / loading): 54 %
 Structure weight / hull surface area: 30 lbs/sq ft or 147 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.43
  - Longitudinal: 3.25
  - Overall: 0.52
 Hull space for machinery, storage, compartmentation is cramped
 Room for accommodation and workspaces is cramped