An anachronistic USS Wampanoag cruiser

I thought that I would like to try an American cruiser, the Wampanoag, as an anachronistic design. I had to modify my anachronistic gun list, first. I will post that separately. I added some protection to the Wampanoag to see if I could increase the roll period. This design is done with the Springsharp 3.0b Beta. I am starting to develop some facility with the program and like it much better than 2.1, which I liked a lot. I like being able to visualize the freeboard and having control over gun lengths. I am still getting the "drive" error message, however. This is the Springsharp report:

Wampanoag, United States Cruiser laid down 1906

Displacement:
 3,500 t light; 3,658 t standard; 4,216 t normal; 4,662 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
 (339.00 ft / 335.00 ft) x 48.00 ft x (18.50 / 19.96 ft)
 (103.33 m / 102.11 m) x 14.63 m  x (5.64 / 6.08 m)

Armament:
      3 - 4.70" / 119 mm 45.0 cal guns - 52.35lbs / 23.75kg shells, 150 per gun
   Quick firing guns in deck and hoist mounts , 1906 Model
   3 x Single mounts on centreline, evenly spread
   Aft Main mounts separated by engine room
      10 - 5.00" / 127 mm 51.0 cal guns - 66.46lbs / 30.15kg shells, 150 per gun
   Quick firing guns in casemate mounts , 1906 Model
   10 x Single mounts on sides, evenly spread
      2 - 4.00" / 102 mm 50.0 cal guns - 33.88lbs / 15.37kg shells, 150 per gun
   Quick firing guns in deck and hoist mounts , 1906 Model
   2 x Single mounts on sides, forward deck aft
 Weight of broadside 889 lbs / 889 kg

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

   - Torpedo Bulkhead:
  0.70" / 18 mm 180.00 ft / 54.86 m 18.50 ft / 5.64 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 3.00" / 76 mm       -   2.00" / 51 mm
 2nd: 3.00" / 76 mm       -   2.00" / 51 mm
 3rd: 2.00" / 51 mm       -   2.00" / 51 mm

   - Armour deck: 1.00" / 25 mm

Machinery:
 Coal fired boilers, complex reciprocating steam engines, 
 ERROR: Revise drives, 2 shafts, 11,965 ihp / 8,926 Kw = 21.00 kts
 Range 5,000nm at 12.00 kts
 Bunker at max displacement = 1,003 tons (100% coal)

Complement:
 261 - 340

Cost:
 £0.419 million / $1.675 million

Distribution of weights at normal displacement:
 Armament: 194 tons, 4.6 %
 Armour: 372 tons, 8.8 %
    - Belts: 0 tons, 0.0 %
    - Torpedo bulkhead: 86 tons, 2.0 %
    - Armament: 88 tons, 2.1 %
    - Armour Deck: 197 tons, 4.7 %
    - Conning Tower: 0 tons, 0.0 %
 Machinery: 1,701 tons, 40.4 %
 Hull, fittings & equipment: 1,358 tons, 32.2 %
 Fuel, ammunition & stores: 716 tons, 17.0 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   2,618 lbs / 1,187 Kg = 50.4 x 4.7 " / 119 mm shells or 0.7 torpedoes
 Stability (Unstable if below 1.00): 1.33
 Metacentric height 2.8 ft / 0.8 m
 Roll period: 12.1 seconds
 Steadiness - As gun platform (Average = 50 %): 100 %
   - Recoil effect (Restricted arc if above 1.00): 0.40
 Seaboat quality  (Average = 1.00): 1.97

Hull form characteristics:
 Hull has a flush deck,
   a normal bow and a round stern
 Block coefficient (normal/deep): 0.496 / 0.508
 Length to Beam Ratio: 6.98 : 1
 'Natural speed' for length: 18.30 kts
 Power going to wave formation at top speed: 54 %
 Trim (Max stability = 0, Max steadiness = 100): 72
 Bow angle (Positive = bow angles forward): 0.00 degrees
 Stern overhang: 4.00 ft / 1.22 m
 Freeboard (% = length of deck as a percentage of waterline length):
    Fore end,  Aft end
    - Forecastle: 25.00 %,  21.00 ft / 6.40 m,  17.00 ft / 5.18 m
    - Forward deck: 30.00 %,  17.00 ft / 5.18 m,  17.00 ft / 5.18 m
    - Aft deck: 30.00 %,  17.00 ft / 5.18 m,  17.00 ft / 5.18 m
    - Quarter deck: 15.00 %,  17.00 ft / 5.18 m,  18.00 ft / 5.49 m
    - Average freeboard:  17.48 ft / 5.33 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 246.8 %
  - Above water (accommodation/working, high = better): 132.4 %
 Waterplane Area: 10,675 Square feet or 992 Square metres
 Displacement factor (Displacement / loading): 97 %
 Structure weight / hull surface area: 72 lbs/sq ft or 354 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.89
  - Longitudinal: 3.07
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is extremely poor
 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