I am disappointed with what I could get from the US/CL/1918 design

I thought that I should be able to achieve a 35 knot speed from my US/CL/1918 design, but the best that I could do was 33 knots. This is a ship that has 9-6in/55 QF guns, 4-3in AA guns, and 6-21in TT. The belt is 3in and the deck is 2in. This is the Springsharp report:

US/CL/1918, United States Light Cruiser laid down 1918 (Engine 1941)

Displacement:
 7,681 t light; 7,951 t standard; 8,566 t normal; 9,058 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
 (611.44 ft / 605.00 ft) x 55.00 ft x (17.00 / 17.76 ft)
 (186.37 m / 184.40 m) x 16.76 m  x (5.18 / 5.41 m)

Armament:
      9 - 6.00" / 152 mm 55.0 cal guns - 115.00lbs / 52.16kg shells, 150 per gun
   Quick firing guns in turret on barbette mounts, 1918 Model
   3 x Triple mounts on centreline ends, evenly spread
  2 raised mounts - superfiring
      4 - 3.00" / 76.2 mm 45.0 cal guns - 13.62lbs / 6.18kg shells, 150 per gun
   Anti-air guns in deck mounts, 1918 Model
   4 x Single mounts on sides, aft deck forward
      Weight of broadside 1,089 lbs / 494 kg
      6 - 21.0" / 533 mm, 20.00 ft / 6.10 m torpedoes - 1.295 t each, 7.769 t total
 In 2 sets of deck mounted carriage/fixed tubes

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 3.00" / 76 mm 420.00 ft / 128.02 m 12.00 ft / 3.66 m
 Ends: Unarmoured
   Main Belt covers 107 % of normal length
   Main belt does not fully cover magazines and engineering spaces

   - Torpedo Bulkhead:
  0.60" / 15 mm 420.00 ft / 128.02 m 17.00 ft / 5.18 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 3.00" / 76 mm 2.00" / 51 mm  3.00" / 76 mm

   - Protected deck - single deck: 2.00" / 51 mm For and Aft decks

   - Conning towers: Forward 4.00" / 102 mm,  Aft 0.00" / 0 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 4 shafts, 86,340 shp / 64,409 Kw = 33.00 kts
 Range 5,600nm at 15.00 kts
 Bunker at max displacement = 1,107 tons

Complement:
 444 - 578

Cost:
 £1.424 million / $5.697 million

Distribution of weights at normal displacement:
 Armament: 311 tons, 3.6 %
    - Guns: 303 tons, 3.5 %
    - Torpedoes: 8 tons, 0.1 %
 Armour: 1,715 tons, 20.0 %
    - Belts: 610 tons, 7.1 %
    - Torpedo bulkhead: 159 tons, 1.9 %
    - Armament: 219 tons, 2.6 %
    - Armour Deck: 692 tons, 8.1 %
    - Conning Tower: 36 tons, 0.4 %
 Machinery: 2,282 tons, 26.6 %
 Hull, fittings & equipment: 3,373 tons, 39.4 %
 Fuel, ammunition & stores: 885 tons, 10.3 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   10,699 lbs / 4,853 Kg = 99.1 x 6.0 " / 152 mm shells or 1.6 torpedoes
 Stability (Unstable if below 1.00): 1.12
 Metacentric height 2.5 ft / 0.8 m
 Roll period: 14.5 seconds
 Steadiness - As gun platform (Average = 50 %): 51 %
   - Recoil effect (Restricted arc if above 1.00): 0.39
 Seaboat quality  (Average = 1.00): 1.03

Hull form characteristics:
 Hull has rise forward of midbreak,
   a normal bow and a cruiser stern
 Block coefficient (normal/deep): 0.530 / 0.537
 Length to Beam Ratio: 11.00 : 1
 'Natural speed' for length: 24.60 kts
 Power going to wave formation at top speed: 56 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 7.00 degrees
 Stern overhang: 3.00 ft / 0.91 m
 Freeboard (% = length of deck as a percentage of waterline length):
    Fore end,  Aft end
    - Forecastle: 20.00 %,  28.00 ft / 8.53 m,  24.00 ft / 7.32 m
    - Forward deck: 15.00 %,  24.00 ft / 7.32 m,  24.00 ft / 7.32 m
    - Aft deck: 50.00 %,  16.00 ft / 4.88 m,  16.00 ft / 4.88 m
    - Quarter deck: 15.00 %,  16.00 ft / 4.88 m,  16.00 ft / 4.88 m
    - Average freeboard:  19.12 ft / 5.83 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 157.1 %
  - Above water (accommodation/working, high = better): 172.9 %
 Waterplane Area: 22,792 Square feet or 2,117 Square metres
 Displacement factor (Displacement / loading): 115 %
 Structure weight / hull surface area: 96 lbs/sq ft or 470 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.99
  - Longitudinal: 1.09
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is cramped
 Room for accommodation and workspaces is excellent