The GB/CS/1915 design from the Red Book

I have had trouble with getting a good result from Springsharp with the GB/CS/1914 scout cruiser. This and a fast gunboat design were conceived by my friend Cliff, back in 1971, as what he wanted to build, starting in 1915. I have tried to stay close to his concept, while working at having an acceptable Springsharp report. The main concern I have about what the design is the roll period is probably too short. The ship has an ambitious 32 knot speed and carries 4-6in QF guns with 4-21in TT. I worked in some light protection, and Springsharp did that while still letting me get by with the fast, light combatant strength (between 0.5 and 1.0). This is the Springsharp report:

GB/CS/1915, Great Britain Scout Cruiser laid down 1915 (Engine 1941)

Displacement:
 2,780 t light; 2,880 t standard; 3,200 t normal; 3,456 t full load

Dimensions: Length overall / water x beam x draught
 409.21 ft / 405.00 ft x 41.00 ft x 15.00 ft (normal load)
 124.73 m / 123.44 m x 12.50 m  x 4.57 m

Armament:
      4 - 6.00" / 152 mm guns in single mounts, 108.00lbs / 48.99kg shells, 1915 Model
   Quick firing guns in deck mounts with hoists
   on centreline ends, evenly spread, 2 raised mounts - superfiring
 Weight of broadside 432 lbs / 196 kg
 Shells per gun, main battery: 150
 4 - 21.0" / 533.4 mm above water torpedoes

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 2.00" / 51 mm 270.00 ft / 82.30 m 9.00 ft / 2.74 m
 Ends: Unarmoured
   Main Belt covers 103 % of normal length
   Main belt does not fully cover magazines and engineering spaces

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 2.00" / 51 mm 2.00" / 51 mm  2.00" / 51 mm

   - Armour deck: 2.00" / 51 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 2 shafts, 48,338 shp / 36,060 Kw = 32.00 kts
 Range 5,400nm at 15.00 kts
 Bunker at max displacement = 576 tons

Complement:
 212 - 276

Cost:
 £0.456 million / $1.825 million

Distribution of weights at normal displacement:
 Armament: 54 tons, 1.7 %
 Armour: 635 tons, 19.8 %
    - Belts: 201 tons, 6.3 %
    - Torpedo bulkhead: 0 tons, 0.0 %
    - Armament: 42 tons, 1.3 %
    - Armour Deck: 392 tons, 12.2 %
    - Conning Tower: 0 tons, 0.0 %
 Machinery: 1,222 tons, 38.2 %
 Hull, fittings & equipment: 870 tons, 27.2 %
 Fuel, ammunition & stores: 420 tons, 13.1 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   1,512 lbs / 686 Kg = 14.0 x 6.0 " / 152 mm shells or 0.6 torpedoes
 Stability (Unstable if below 1.00): 1.33
 Metacentric height 2.2 ft / 0.7 m
 Roll period: 11.7 seconds
 Steadiness - As gun platform (Average = 50 %): 51 %
   - Recoil effect (Restricted arc if above 1.00): 0.36
 Seaboat quality  (Average = 1.00): 1.02

Hull form characteristics:
 Hull has raised forecastle, rise forward of midbreak
 Block coefficient: 0.450
 Length to Beam Ratio: 9.88 : 1
 'Natural speed' for length: 20.12 kts
 Power going to wave formation at top speed: 64 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 6.00 degrees
 Stern overhang: 2.00 ft / 0.61 m
 Freeboard (% = measuring location as a percentage of overall length):
    - Stem:  21.00 ft / 6.40 m
    - Forecastle (20 %): 18.00 ft / 5.49 m (17.00 ft / 5.18 m aft of break)
    - Mid (50 %):  16.00 ft / 4.88 m (15.00 ft / 4.57 m aft of break)
    - Quarterdeck (15 %): 14.00 ft / 4.27 m
    - Stern:  14.00 ft / 4.27 m
    - Average freeboard: 15.97 ft / 4.87 m
 Ship tends to be wet forward

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 136.7 %
  - Above water (accommodation/working, high = better): 122.4 %
 Waterplane Area: 10,589 Square feet or 984 Square metres
 Displacement factor (Displacement / loading): 88 %
 Structure weight / hull surface area: 45 lbs/sq ft or 219 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.57
  - Longitudinal: 1.44
  - Overall: 0.62
 Hull space for machinery, storage, compartmentation is cramped
 Room for accommodation and workspaces is excellent