Aosta Class Crusier

[snip]

The last of the Hexagons, the Astoa class trades some armor for additional speed and also gains minelaying capabilities.

Four Ships
--IRS Aosta
--IRS Dertona (Sunk August 1914)
--IRS Verona
--IRS Param

Aosta, Imperial Roman Republic Cruiser laid down 1899

Displacement:
   3,500 t light; 3,628 t standard; 4,012 t normal; 4,319 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (314.96 ft / 308.40 ft) x 42.65 ft x (20.51 / 21.71 ft)
   (96.00 m / 94.00 m) x 13.00 m  x (6.25 / 6.62 m)

Armament:
      6 - 5.51" / 140 mm 45.0 cal guns - 79.37lbs / 36.00kg shells, 125 per gun
     Quick firing guns in deck mounts, 1897 Model
     2 x Single mounts on centreline ends, evenly spread
     4 x Single mounts on side ends, evenly spread
      8 - 2.95" / 75.0 mm 45.0 cal guns - 13.23lbs / 6.00kg shells, 250 per gun
     Quick firing guns in deck mounts, 1897 Model
     6 x Single mounts on sides, evenly spread
     2 x Single mounts on sides, aft deck aft
      2 hull mounts in casemates- Limited use in all but light seas
      Weight of broadside 582 lbs / 264 kg

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   0.79" / 20 mm   308.40 ft / 94.00 m   7.84 ft / 2.39 m
     Main Belt covers 154 % of normal length
     Main belt does not fully cover magazines and engineering spaces

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   1.97" / 50 mm         -               -
   2nd:   0.59" / 15 mm         -               -

   - Protected deck - single deck:
   For and Aft decks: 1.57" / 40 mm
   Forecastle: 1.18" / 30 mm  Quarter deck: 1.18" / 30 mm

   - Conning towers: Forward 3.94" / 100 mm, Aft 0.00" / 0 mm

Machinery:
   Coal fired boilers, complex reciprocating steam engines,
   Direct drive, 2 shafts, 12,000 ihp / 8,952 Kw = 20.96 kts
   Range 4,750nm at 10.00 kts
   Bunker at max displacement = 691 tons (100% coal)

Complement:
   251 - 327

Cost:
   £0.411 million / $1.642 million

Distribution of weights at normal displacement:
   Armament: 107 tons, 2.7 %
      - Guns: 107 tons, 2.7 %
   Armour: 391 tons, 9.7 %
      - Belts: 70 tons, 1.8 %
      - Armament: 42 tons, 1.0 %
      - Armour Deck: 257 tons, 6.4 %
      - Conning Tower: 21 tons, 0.5 %
   Machinery: 1,849 tons, 46.1 %
   Hull, fittings & equipment: 969 tons, 24.1 %
   Fuel, ammunition & stores: 512 tons, 12.8 %
   Miscellaneous weights: 185 tons, 4.6 %
      - Hull below water: 25 tons
      - Hull above water: 70 tons
      - On freeboard deck: 80 tons
      - Above deck: 10 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     1,970 lbs / 893 Kg = 23.5 x 5.5 " / 140 mm shells or 0.5 torpedoes
   Stability (Unstable if below 1.00): 1.55
   Metacentric height 2.9 ft / 0.9 m
   Roll period: 10.5 seconds
   Steadiness   - As gun platform (Average = 50 %): 69 %
         - Recoil effect (Restricted arc if above 1.00): 0.17
   Seaboat quality  (Average = 1.00): 1.54

Hull form characteristics:
   Hull has low quarterdeck ,
     a ram bow and a cruiser stern
   Block coefficient (normal/deep): 0.521 / 0.529
   Length to Beam Ratio: 7.23 : 1
   'Natural speed' for length: 17.56 kts
   Power going to wave formation at top speed: 56 %
   Trim (Max stability = 0, Max steadiness = 100): 45
   Bow angle (Positive = bow angles forward): -20.00 degrees
   Stern overhang: -3.28 ft / -1.00 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
      - Forecastle:   10.00 %,  15.58 ft / 4.75 m,  15.58 ft / 4.75 m
      - Forward deck:   40.00 %,  15.58 ft / 4.75 m,  15.58 ft / 4.75 m
      - Aft deck:   40.00 %,  15.58 ft / 4.75 m,  15.58 ft / 4.75 m
      - Quarter deck:   10.00 %,  6.56 ft / 2.00 m,  6.56 ft / 2.00 m
      - Average freeboard:      14.68 ft / 4.48 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 158.9 %
      - Above water (accommodation/working, high = better): 105.6 %
   Waterplane Area: 8,932 Square feet or 830 Square metres
   Displacement factor (Displacement / loading): 86 %
   Structure weight / hull surface area: 65 lbs/sq ft or 317 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.89
      - Longitudinal: 2.92
      - Overall: 1.00
   Cramped machinery, storage, compartmentation space
   Adequate accommodation and workspace room
   Excellent seaboat, comfortable, can fire her guns in the heaviest weather

Misc Distribution
--Below Water (25t)
----20t 10x350mm Torpedos (45 Pattern A)
----2t Additional Torpedo Handing Equipment
----5t Additional Pumps
--Above Water (70t)
----10t Improved Officer Accommodations
----10t Improved Crew Accommodations
----20t Additional Troop Compliment
----5t Construction Reserve
--On Deck (80t)
----30t Additional Troop Compliment
----10t Flag Facilities
----5t Admiralty Accommodations
----30t Mines and Minelaying Equipment
----5t Construction Reserve
--Above Deck (10t)
----5t Improved Aquisition Structures
----5t Additional Searchlights

[snip]

The three surviving ships of this class were scrapped in 1926H1.