The Swiftsure and Triumph design requires very lightweight machinery

I had done a design for the light battleships Swiftsure and Triumph, in the usual anachronistic style. The hull is flush-decked, with a flared bow. The armament is in two twin 10in turrets, two triple 7.5in turrets, in the superfiring position, and four twin 7.5in turrets, on the beam. There are also 16-3in QF guns in twin mounts with shields. The armour basis is 7in with a 2in deck. The speed is 20 knots. This is the Springsharp report:

Swiftsure and Triumph (anachronistic), Great Britain Battleship laid down 1912 (Engine 1910)

Displacement:
 12,221 t light; 12,815 t standard; 14,050 t normal; 15,038 t full load

Dimensions: Length overall / water x beam x draught
 471.54 ft / 470.00 ft x 70.00 ft x 24.00 ft (normal load)
 143.72 m / 143.26 m x 21.34 m  x 7.32 m

Armament:
      4 - 10.00" / 254 mm guns (2x2 guns), 500.00lbs / 226.80kg shells, 1912 Model
   Breech loading guns in turrets (on barbettes)
   on centreline ends, evenly spread
      6 - 7.50" / 191 mm guns (2x3 guns), 210.94lbs / 95.68kg shells, 1912 Model
   Breech loading guns in turrets (on barbettes)
   on centreline ends, evenly spread, all raised mounts
      8 - 7.50" / 191 mm guns (4x2 guns), 210.94lbs / 95.68kg shells, 1912 Model
   Breech loading guns in turrets (on barbettes)
   on side, all amidships
      16 - 3.00" / 76.2 mm guns (8x2 guns), 13.50lbs / 6.12kg shells, 1912 Model
   Quick firing guns in deck mounts with hoists
   on side, all amidships, all raised mounts - superfiring
 Weight of broadside 5,169 lbs / 2,345 kg
 Shells per gun, main battery: 100

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 7.00" / 178 mm 300.00 ft / 91.44 m 16.00 ft / 4.88 m
 Ends: 3.00" / 76 mm 170.00 ft / 51.82 m 16.00 ft / 4.88 m
   Main Belt covers 98 % of normal length

   - Torpedo Bulkhead:
  2.00" / 51 mm 300.00 ft / 91.44 m 24.00 ft / 7.32 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 10.0" / 254 mm 7.00" / 178 mm  10.0" / 254 mm
 2nd: 5.00" / 127 mm 4.00" / 102 mm  5.00" / 127 mm
 3rd: 5.00" / 127 mm 4.00" / 102 mm  5.00" / 127 mm
 4th: 2.00" / 51 mm 1.00" / 25 mm  2.00" / 51 mm

   - Armour deck: 3.00" / 76 mm, Conning tower: 10.00" / 254 mm

Machinery:
 Coal fired boilers, complex reciprocating steam engines, 
 Direct drive, 2 shafts, 19,430 ihp / 14,495 Kw = 20.00 kts
 Range 5,600nm at 12.00 kts
 Bunker at max displacement = 2,223 tons (100% coal)

Complement:
 644 - 838

Cost:
 £1.152 million / $4.607 million

Distribution of weights at normal displacement:
 Armament: 646 tons, 4.6 %
 Armour: 5,216 tons, 37.1 %
    - Belts: 1,773 tons, 12.6 %
    - Torpedo bulkhead: 533 tons, 3.8 %
    - Armament: 1,421 tons, 10.1 %
    - Armour Deck: 1,364 tons, 9.7 %
    - Conning Tower: 125 tons, 0.9 %
 Machinery: 1,295 tons, 9.2 %
 Hull, fittings & equipment: 5,064 tons, 36.0 %
 Fuel, ammunition & stores: 1,829 tons, 13.0 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   20,807 lbs / 9,438 Kg = 41.6 x 10.0 " / 254 mm shells or 4.0 torpedoes
 Stability (Unstable if below 1.00): 1.03
 Metacentric height 3.1 ft / 1.0 m
 Roll period: 16.6 seconds
 Steadiness - As gun platform (Average = 50 %): 75 %
   - Recoil effect (Restricted arc if above 1.00): 0.89
 Seaboat quality  (Average = 1.00): 1.51

Hull form characteristics:
 Hull has a flush deck
 Block coefficient: 0.623
 Length to Beam Ratio: 6.71 : 1
 'Natural speed' for length: 21.68 kts
 Power going to wave formation at top speed: 47 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 4.00 degrees
 Stern overhang: -2.00 ft / -0.61 m
 Freeboard (% = measuring location as a percentage of overall length):
    - Stem:  22.00 ft / 6.71 m
    - Forecastle (18 %): 18.00 ft / 5.49 m
    - Mid (50 %):  18.00 ft / 5.49 m
    - Quarterdeck (15 %): 18.00 ft / 5.49 m
    - Stern:  18.00 ft / 5.49 m
    - Average freeboard: 18.29 ft / 5.57 m
 Ship tends to be wet forward

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 91.3 %
  - Above water (accommodation/working, high = better): 130.9 %
 Waterplane Area: 24,578 Square feet or 2,283 Square metres
 Displacement factor (Displacement / loading): 108 %
 Structure weight / hull surface area: 139 lbs/sq ft or 680 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.94
  - Longitudinal: 1.80
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is adequate
 Room for accommodation and workspaces is excellent
 Ship has slow, easy roll, a good, steady gun platform
 Excellent seaboat, comfortable, can fire her guns in the heaviest weather