Did anyone think about

[Tanthalas]

the fact that you have to train your officers?  I just thought of it, so i poresent... a Gunery trainer

Italia TC-1905, Italia Training Cruiser laid down 1905

Displacement:
   1,694 t light; 1,942 t standard; 2,000 t normal; 2,047 t full load

Dimensions: Length overall / water x beam x draught
   200.00 ft / 200.00 ft x 60.00 ft x 12.00 ft (normal load)
   60.96 m / 60.96 m x 18.29 m  x 3.66 m

Armament:
      4 - 10.00" / 254 mm guns (2x2 guns), 500.00lbs / 226.80kg shells, 1905 Model
     Breech loading guns in turrets (on barbettes)
     on centreline ends, evenly spread
      6 - 5.00" / 127 mm guns in single mounts, 62.50lbs / 28.35kg shells, 1905 Model
     Breech loading guns in casemate mounts
     on side, all amidships
      2 - 3.00" / 76.2 mm guns (1x2 guns), 13.50lbs / 6.12kg shells, 1905 Model
     Breech loading guns in a deck mount with hoist
     on side
   Weight of broadside 2,402 lbs / 1,090 kg
   Shells per gun, main battery: 150
   1 - 20.0" / 508 mm submerged torpedo tubes

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   1.00" / 25 mm   1.00" / 25 mm      1.00" / 25 mm
   2nd:   1.00" / 25 mm   1.00" / 25 mm            -

Machinery:
   Coal fired boilers, simple reciprocating steam engines,
   Direct drive, 1 shaft, 567 ihp / 423 Kw = 10.00 kts
   Range 1,000nm at 10.00 kts
   Bunker at max displacement = 105 tons (100% coal)

Complement:
   149 - 194

Cost:
   £0.323 million / $1.291 million

Distribution of weights at normal displacement:
   Armament: 300 tons, 15.0 %
   Armour: 68 tons, 3.4 %
      - Belts: 0 tons, 0.0 %
      - Torpedo bulkhead: 0 tons, 0.0 %
      - Armament: 68 tons, 3.4 %
      - Armour Deck: 0 tons, 0.0 %
      - Conning Tower: 0 tons, 0.0 %
   Machinery: 80 tons, 4.0 %
   Hull, fittings & equipment: 1,206 tons, 60.3 %
   Fuel, ammunition & stores: 306 tons, 15.3 %
   Miscellaneous weights: 40 tons, 2.0 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     1,303 lbs / 591 Kg = 2.6 x 10.0 " / 254 mm shells or 0.7 torpedoes
   Stability (Unstable if below 1.00): 1.31
   Metacentric height 3.8 ft / 1.2 m
   Roll period: 13.0 seconds
   Steadiness   - As gun platform (Average = 50 %): 80 %
         - Recoil effect (Restricted arc if above 1.00): 0.48
   Seaboat quality  (Average = 1.00): 1.59

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0.486
   Length to Beam Ratio: 3.33 : 1
   'Natural speed' for length: 14.14 kts
   Power going to wave formation at top speed: 36 %
   Trim (Max stability = 0, Max steadiness = 100): 50
   Bow angle (Positive = bow angles forward): 0.00 degrees
   Stern overhang: 0.00 ft / 0.00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      15.56 ft / 4.74 m
      - Forecastle (20 %):   9.90 ft / 3.02 m
      - Mid (50 %):      9.90 ft / 3.02 m
      - Quarterdeck (15 %):   9.90 ft / 3.02 m
      - Stern:      9.90 ft / 3.02 m
      - Average freeboard:   10.35 ft / 3.16 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 134.8 %
      - Above water (accommodation/working, high = better): 95.8 %
   Waterplane Area: 7,571 Square feet or 703 Square metres
   Displacement factor (Displacement / loading): 74 %
   Structure weight / hull surface area: 125 lbs/sq ft or 610 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.84
      - Longitudinal: 4.54
      - Overall: 1.00
   Hull space for machinery, storage, compartmentation is cramped
   Room for accommodation and workspaces is adequate
   Ship has slow, easy roll, a good, steady gun platform
   Excellent seaboat, comfortable, can fire her guns in the heaviest weather

[The Rock Doctor]

Gran Colombia retains an ex-ACM battleship and an ex-IC armored cruiser for this purpose.

I like the idea, but think she'd be rather crowded above-deck.  Perhaps consider dumping one of the two big turrets, and adding some armor - then she can double as a monitor during military operations.