The Ger/DD/1915 design vs. my original concept

My Ger/DD/1915 destroyer design was predicated on very lightweight machinery. The displacement was to be 800 tons and the dimensions were 240ft x 26ft. The armament was 2-4in QF guns, 4-21in TT, and 20 mines. The speed was not specified, but the best that I could do with Springsharp was about 32 knots. This is a comparison between the original concept and the Springsharp design:

            Original     Springsharp
Armament:    20 tons        8 tons
Machinery:  444 tons      410 tons
Hull:       272 tons      275 tons
Misc:        64 tons       88 tons
Oil Fuel:   200 tons      119 tons
Feedwater:   50 tons

This is the Springsharp report:

Ger/DD/1915, Germany Destroyer laid down 1915 (Engine 1950)

Displacement:
 712 t light; 734 t standard; 800 t normal; 853 t full load

Dimensions: Length overall / water x beam x draught
 243.77 ft / 240.00 ft x 26.00 ft x 11.00 ft (normal load)
 74.30 m / 73.15 m x 7.92 m  x 3.35 m

Armament:
     2 - 4.00" / 102 mm guns in single mounts, 32.00lbs / 14.51kg shells, 1915 Model
   Quick firing guns in deck mounts with hoists
   on centreline ends, evenly spread
 Weight of broadside 64 lbs / 29 kg
 Shells per gun, main battery: 150
 4 - 21.0" / 533.4 mm above water torpedoes

Machinery:
 Oil fired boilers, steam turbines,
 Geared drive, 2 shafts, 27,020 shp / 20,157 Kw = 32.00 kts
 Range 2,600nm at 15.00 kts
 Bunker at max displacement = 119 tons

Complement:
 74 - 97

Cost:
 £0.129 million / $0.518 million

Distribution of weights at normal displacement:
 Armament: 8 tons, 1.0 %
 Machinery: 410 tons, 51.2 %
 Hull, fittings & equipment: 275 tons, 34.3 %
 Fuel, ammunition & stores: 88 tons, 11.0 %
 Miscellaneous weights: 20 tons, 2.5 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   229 lbs / 104 Kg = 7.2 x 4.0 " / 102 mm shells or 0.2 torpedoes
 Stability (Unstable if below 1.00): 1.18
 Metacentric height 0.9 ft / 0.3 m
 Roll period: 11.5 seconds
 Steadiness - As gun platform (Average = 50 %): 52 %
   - Recoil effect (Restricted arc if above 1.00): 0.28
 Seaboat quality  (Average = 1.00): 1.04

Hull form characteristics:
 Hull has rise forward of midbreak
 Block coefficient: 0.408
 Length to Beam Ratio: 9.23 : 1
 'Natural speed' for length: 15.49 kts
 Power going to wave formation at top speed: 74 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 2.00 degrees
 Stern overhang: 3.00 ft / 0.91 m
 Freeboard (% = measuring location as a percentage of overall length):
    - Stem:  22.00 ft / 6.71 m
    - Forecastle (20 %): 21.00 ft / 6.40 m
    - Mid (22 %):  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: 14.84 ft / 4.52 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 175.7 %
  - Above water (accommodation/working, high = better): 73.5 %
 Waterplane Area: 3,859 Square feet or 359 Square metres
 Displacement factor (Displacement / loading): 58 %
 Structure weight / hull surface area: 27 lbs/sq ft or 130 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.44
  - Longitudinal: 6.49
  - Overall: 0.58
 Hull space for machinery, storage, compartmentation is cramped
 Room for accommodation and workspaces is cramped