The GB/DD/1921 design

I was going to just settle for a modest increase in speed and range, but I decided at the last minute to add a fifth 4.7in QF gun to the GB/DD/1921 design. The maximum speed is now 36 knots with a range of 4,500nm at 12 knots. This is the Springsharp report:

GB/DD/1921, Great Britain Destroyer laid down 1921 (Engine 1931)

Displacement:
 1,348 t light; 1,409 t standard; 1,520 t normal; 1,609 t full load

Dimensions: Length overall / water x beam x draught
 336.21 ft / 335.00 ft x 32.00 ft x 13.00 ft (normal load)
 102.48 m / 102.11 m x 9.75 m  x 3.96 m

Armament:
      5 - 4.70" / 119 mm guns (4 mounts), 51.91lbs / 23.55kg shells, 1921 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), 1.95lbs / 0.89kg shells, 1921 Model
   Anti-aircraft guns in deck mount 
   on side amidships, all raised guns
 Weight of broadside 267 lbs / 121 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, 43,455 shp / 32,417 Kw = 36.00 kts
 Range 4,500nm at 12.00 kts
 Bunker at max displacement = 200 tons

Complement:
 121 - 158

Cost:
 £0.489 million / $1.957 million

Distribution of weights at normal displacement:
 Armament: 33 tons, 2.2 %
 Machinery: 836 tons, 55.0 %
 Hull, fittings & equipment: 479 tons, 31.5 %
 Fuel, ammunition & stores: 172 tons, 11.3 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   338 lbs / 153 Kg = 6.5 x 4.7 " / 119 mm shells or 0.2 torpedoes
 Stability (Unstable if below 1.00): 1.31
 Metacentric height 1.5 ft / 0.4 m
 Roll period: 11.1 seconds
 Steadiness - As gun platform (Average = 50 %): 51 %
   - Recoil effect (Restricted arc if above 1.00): 0.57
 Seaboat quality  (Average = 1.00): 1.03

Hull form characteristics:
 Hull has rise forward of midbreak
   and transom stern
 Block coefficient: 0.382
 Length to Beam Ratio: 10.47 : 1
 'Natural speed' for length: 21.15 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): 194.7 %
  - Above water (accommodation/working, high = better): 77.0 %
 Waterplane Area: 6,786 Square feet or 630 Square metres
 Displacement factor (Displacement / loading): 53 %
 Structure weight / hull surface area: 31 lbs/sq ft or 153 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.42
  - Longitudinal: 2.94
  - Overall: 0.51
 Hull space for machinery, storage, compartmentation is cramped
 Room for accommodation and workspaces is cramped