Another run at the GB/PGL/1906

I thought I would try again to produce an acceptable design for the GB/PGL/1906. This was my friend Cliff's idea of a large, fast, destroyer-like vessel armed with 3-5in QF guns with no torpedo tubes. The ship would be able to make a top speed of 36 knots and would be 340ft long. I tried cranking the year for the machinery out to 1937, but could only muster a power to weight ratio of not quite 56 SHP/ton. Remember that the real British super-destroyer Swift could do as much as 64 SHP/ton, when pressed. That was in 1907! Here is the Springsharp report:

GB/PGL/1906, Great Britain Fast Large Gunboat laid down 1906 (Engine 1937)

Displacement:
 1,504 t light; 1,552 t standard; 1,627 t normal; 1,687 t full load

Dimensions: Length overall / water x beam x draught
 340.87 ft / 340.00 ft x 35.00 ft x 15.00 ft (normal load)
 103.90 m / 103.63 m x 10.67 m  x 4.57 m

Armament:
      3 - 5.00" / 127 mm guns in single mounts, 62.50lbs / 28.35kg shells, 1906 Model
   Breech loading guns in deck mounts with hoists
   on centreline ends, majority forward, all raised mounts - superfiring
 Weight of broadside 188 lbs / 85 kg
 Shells per gun, main battery: 150

Machinery:
 Oil fired boilers, steam turbines, 
 Direct drive, 4 shafts, 52,813 shp / 39,398 Kw = 36.00 kts
 Range 2,750nm at 12.00 kts
 Bunker at max displacement = 134 tons

Complement:
 127 - 166

Cost:
 £0.205 million / $0.818 million

Distribution of weights at normal displacement:
 Armament: 23 tons, 1.4 %
 Machinery: 944 tons, 58.0 %
 Hull, fittings & equipment: 536 tons, 33.0 %
 Fuel, ammunition & stores: 123 tons, 7.6 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   311 lbs / 141 Kg = 5.0 x 5.0 " / 127 mm shells or 0.2 torpedoes
 Stability (Unstable if below 1.00): 1.40
 Metacentric height 1.9 ft / 0.6 m
 Roll period: 10.8 seconds
 Steadiness - As gun platform (Average = 50 %): 51 %
   - Recoil effect (Restricted arc if above 1.00): 0.20
 Seaboat quality  (Average = 1.00): 1.02

Hull form characteristics:
 Hull has rise forward of midbreak, raised quarterdeck 
 Block coefficient: 0.319
 Length to Beam Ratio: 9.71 : 1
 'Natural speed' for length: 18.44 kts
 Power going to wave formation at top speed: 67 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 2.00 degrees
 Stern overhang: 0.00 ft / 0.00 m
 Freeboard (% = measuring location as a percentage of overall length):
    - Stem:  25.00 ft / 7.62 m
    - Forecastle (36 %): 23.00 ft / 7.01 m
    - Mid (36 %):  23.00 ft / 7.01 m (15.00 ft / 4.57 m aft of break)
    - Quarterdeck (15 %): 15.00 ft / 4.57 m (3.00 ft / 0.91 m before break)
    - Stern:  15.00 ft / 4.57 m
    - Average freeboard: 15.23 ft / 4.64 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 198.2 %
  - Above water (accommodation/working, high = better): 99.4 %
 Waterplane Area: 7,367 Square feet or 684 Square metres
 Displacement factor (Displacement / loading): 52 %
 Structure weight / hull surface area: 36 lbs/sq ft or 176 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.50
  - Longitudinal: 2.70
  - Overall: 0.59
 Hull space for machinery, storage, compartmentation is cramped
 Room for accommodation and workspaces is adequate