Another attempt at the HMS Unapproachable concept

This version of the HMS Unapproachable differs from what I have been doing in having reciprocating engines, rather than turbines. This version also has coal-fired boilers. I have tried to achieve the weights in the specification, but there is an issue in that it takes more than 40,000 ihp to reach 25.5 knots, with Springsharp. I punted on the armament layout, and assume the 9.2in guns are all on the same level. The 4in QF guns are mounted above them, in casemates. This is the Springsharp report:

HMS Unapproachable October 1904, Great Britain Armoured Cruiser laid down 1904 (Engine 1912)

Displacement:
    16,340 t light; 17,075 t standard; 18,700 t normal; 20,000 t full load

Dimensions: Length overall / water x beam x draught
    554.00 ft / 554.00 ft x 75.00 ft x 26.50 ft (normal load)
    168.86 m / 168.86 m x 22.86 m  x 8.08 m

Armament:
      4 - 9.20" / 234 mm guns (2x2 guns), 389.34lbs / 176.60kg shells, 1904 Model
      Breech loading guns in turrets (on barbettes)
      on centreline ends, evenly spread
      12 - 9.20" / 234 mm guns (6x2 guns), 389.34lbs / 176.60kg shells, 1904 Model
      Breech loading guns in turrets (on barbettes)
      on side, all amidships
      12 - 4.00" / 102 mm guns in single mounts, 32.00lbs / 14.51kg shells, 1904 Model
      Quick firing guns in casemate mounts
      on side, evenly spread, all raised mounts
    Weight of broadside 6,614 lbs / 3,000 kg
    Shells per gun, main battery: 90

Armour:
   - Belts:        Width (max)    Length (avg)        Height (avg)
    Main:    6.00" / 152 mm    360.00 ft / 109.73 m    8.00 ft / 2.44 m
    Ends:    4.00" / 102 mm    194.00 ft / 59.13 m    8.00 ft / 2.44 m
    Upper:    4.00" / 102 mm    360.00 ft / 109.73 m    8.00 ft / 2.44 m
      Main Belt covers 100 % of normal length
      Main belt does not fully cover magazines and engineering spaces

   - Torpedo Bulkhead:
        1.50" / 38 mm    360.00 ft / 109.73 m    26.50 ft / 8.08 m

   - Gun armour:    Face (max)    Other gunhouse (avg)    Barbette/hoist (max)
    Main:    8.00" / 203 mm    5.00" / 127 mm        8.00" / 203 mm
    2nd:    8.00" / 203 mm    5.00" / 127 mm        8.00" / 203 mm
    3rd:    4.00" / 102 mm    4.00" / 102 mm        4.00" / 102 mm

   - Armour deck: 2.00" / 51 mm, Conning tower: 8.00" / 203 mm

Machinery:
    Coal fired boilers, complex reciprocating steam engines,
    Direct drive, 4 shafts, 55,488 ihp / 41,394 Kw = 25.50 kts
    Range 3,800nm at 15.00 kts
    Bunker at max displacement = 2,925 tons (100% coal)

Complement:
    799 - 1,039

Cost:
    £1.781 million / $7.123 million

Distribution of weights at normal displacement:
    Armament: 827 tons, 4.4 %
    Armour: 5,233 tons, 28.0 %
       - Belts: 1,468 tons, 7.9 %
       - Torpedo bulkhead: 529 tons, 2.8 %
       - Armament: 1,995 tons, 10.7 %
       - Armour Deck: 1,119 tons, 6.0 %
       - Conning Tower: 121 tons, 0.6 %
    Machinery: 3,675 tons, 19.7 %
    Hull, fittings & equipment: 6,606 tons, 35.3 %
    Fuel, ammunition & stores: 2,360 tons, 12.6 %
    Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
    Survivability (Non-critical penetrating hits needed to sink ship):
      19,743 lbs / 8,955 Kg = 50.7 x 9.2 " / 234 mm shells or 2.7 torpedoes
    Stability (Unstable if below 1.00): 1.09
    Metacentric height 3.8 ft / 1.2 m
    Roll period: 16.2 seconds
    Steadiness    - As gun platform (Average = 50 %): 59 %
            - Recoil effect (Restricted arc if above 1.00): 0.75
    Seaboat quality  (Average = 1.00): 1.17

Hull form characteristics:
    Hull has a flush deck
    Block coefficient: 0.594
    Length to Beam Ratio: 7.39 : 1
    'Natural speed' for length: 23.54 kts
    Power going to wave formation at top speed: 54 %
    Trim (Max stability = 0, Max steadiness = 100): 50
    Bow angle (Positive = bow angles forward): -2.00 degrees
    Stern overhang: -2.00 ft / -0.61 m
    Freeboard (% = measuring location as a percentage of overall length):
       - Stem:        24.00 ft / 7.32 m
       - Forecastle (20 %):    21.00 ft / 6.40 m
       - Mid (50 %):        21.00 ft / 6.40 m
       - Quarterdeck (15 %):    21.00 ft / 6.40 m
       - Stern:        21.00 ft / 6.40 m
       - Average freeboard:    21.24 ft / 6.47 m
    Ship tends to be wet forward

Ship space, strength and comments:
    Space    - Hull below water (magazines/engines, low = better): 132.3 %
        - Above water (accommodation/working, high = better): 151.3 %
    Waterplane Area: 30,231 Square feet or 2,809 Square metres
    Displacement factor (Displacement / loading): 97 %
    Structure weight / hull surface area: 143 lbs/sq ft or 699 Kg/sq metre
    Hull strength (Relative):
        - Cross-sectional: 0.95
        - Longitudinal: 1.57
        - Overall: 1.00
    Hull space for machinery, storage, compartmentation is cramped
    Room for accommodation and workspaces is excellent