Something about my anachronistic Inconstant design is bothering Springsharp 3.0b1 Beta

I was surprised that I am having so much trouble with Springsharp 3.0b1 Beta, tonight. It has been well-behaved as of late, so this is a nasty surprise. The problem has to do with boilers, percentage coal, and drives. I still have a drive error and can't tell why. I am trying to make an anachronistic Inconstant design. For whatever reason, this has triggered by Springsharp woes. I used my one rule for converting 1860's and 1870's guns to more modern guns, so that the anachronistic ship has 10-7.6in/40 BLR and 6-5.5in/50 QF guns. I moved all the guns to casemates on the hull, so that fixed my recoil and stability problems. The ship is pretty well-protected with a 3in deck and a 1in torpedo bulkhead. This is the Springsharp report:

Inconstant, anachronistic, Great Britain Cruiser laid down 1907 (Engine 1909)

Displacement:
 4,267 t light; 4,598 t standard; 5,684 t normal; 6,553 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
 (348.00 ft / 337.00 ft) x 50.00 ft x (25.50 / 28.30 ft)
 (106.07 m / 102.72 m) x 15.24 m  x (7.77 / 8.63 m)

Armament:
      10 - 7.60" / 193 mm 40.0 cal guns - 210.00lbs / 95.25kg shells, 150 per gun
   Breech loading guns in casemate mounts , 1907 Model
   10 x Single mounts on sides, evenly spread
  10 hull mounts in casemates- Limited use in heavy seas
      6 - 5.50" / 140 mm 50.0 cal guns - 85.00lbs / 38.56kg shells, 150 per gun
   Quick firing guns in casemate mounts , 1907 Model
   6 x Single mounts on sides, evenly spread
  6 hull mounts in casemates- Limited use in heavy seas
 Weight of broadside 2,610 lbs / 2,610 kg

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Ends: Unarmoured

   - Torpedo Bulkhead:
  1.00" / 25 mm 215.00 ft / 65.53 m 25.50 ft / 7.77 m

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

   - Armour deck: 3.00" / 76 mm, Conning tower: 4.00" / 102 mm

Machinery:
 Oil fired boilers, steam turbines, 
 ERROR: Revise drives, 2 shafts, 31,724 shp / 23,666 Kw = 25.50 kts
 Range 5,600nm at 16.00 kts
 Bunker at max displacement = 1,955 tons

Complement:
 326 - 425

Cost:
 £0.467 million / $1.867 million

Distribution of weights at normal displacement:
 Armament: 374 tons, 6.6 %
 Armour: 1,146 tons, 20.2 %
    - Belts: 0 tons, 0.0 %
    - Torpedo bulkhead: 203 tons, 3.6 %
    - Armament: 313 tons, 5.5 %
    - Armour Deck: 603 tons, 10.6 %
    - Conning Tower: 27 tons, 0.5 %
 Machinery: 1,442 tons, 25.4 %
 Hull, fittings & equipment: 1,541 tons, 27.1 %
 Fuel, ammunition & stores: 1,417 tons, 24.9 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   6,990 lbs / 3,170 Kg = 31.8 x 7.6 " / 193 mm shells or 1.3 torpedoes
 Stability (Unstable if below 1.00): 1.96
 Metacentric height 5.2 ft / 1.6 m
 Roll period: 9.2 seconds
 Steadiness - As gun platform (Average = 50 %): 62 %
   - Recoil effect (Restricted arc if above 1.00): 0.18
 Seaboat quality  (Average = 1.00): 1.24

Hull form characteristics:
 Hull has a flush deck,
   a ram bow and a round stern
 Block coefficient (normal/deep): 0.463 / 0.481
 Length to Beam Ratio: 6.74 : 1
 'Natural speed' for length: 18.36 kts
 Power going to wave formation at top speed: 63 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): -3.00 degrees
 Stern overhang: 6.00 ft / 1.83 m
 Freeboard (% = length of deck as a percentage of waterline length):
    Fore end,  Aft end
    - Forecastle: 20.00 %,  19.00 ft / 5.79 m,  17.00 ft / 5.18 m
    - Forward deck: 30.00 %,  17.00 ft / 5.18 m,  16.00 ft / 4.88 m
    - Aft deck: 35.00 %,  16.00 ft / 4.88 m,  16.00 ft / 4.88 m
    - Quarter deck: 15.00 %,  16.00 ft / 4.88 m,  17.00 ft / 5.18 m
    - Average freeboard:  16.59 ft / 5.06 m
 Ship tends to be wet forward

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 172.8 %
  - Above water (accommodation/working, high = better): 103.0 %
 Waterplane Area: 10,865 Square feet or 1,009 Square metres
 Displacement factor (Displacement / loading): 111 %
 Structure weight / hull surface area: 78 lbs/sq ft or 379 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.86
  - Longitudinal: 4.11
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is cramped
 Room for accommodation and workspaces is adequate
 Good seaboat, rides out heavy weather easily