Marathona Class Cruiser - Flying Off Conversion

[snip]

A conversion under consideration for practical study of flying off decks. The old scout cruiser IRS Marathona, the rest of her class headed to the breakers, may have some usefulness here.

Marathona, Roman Imperial Republic Flying Off Deck Conversion (OG Engines) laid down 1908

Displacement:
   3,036 t light; 3,109 t standard; 3,292 t normal; 3,438 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (423.22 ft / 410.11 ft) x 42.65 ft x (13.94 / 14.39 ft)
   (129.00 m / 125.00 m) x 13.00 m  x (4.25 / 4.39 m)

Armament:
      2 - 3.94" / 100 mm 45.0 cal guns - 30.86lbs / 14.00kg shells, 200 per gun
     Quick firing guns in deck mount, 1909 Model
     1 x Twin mount on centreline, aft deck aft
      4 - 0.26" / 6.5 mm 110.0 cal guns - 0.01lbs / 0.00kg shells, 10,000 per gun
     Machine guns in deck mounts, 1911 Model
     4 x Single mounts on sides, aft evenly spread
      4 raised mounts
      Weight of broadside 62 lbs / 28 kg

Armour:
   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   0.39" / 10 mm         -               -
   2nd:   0.20" / 5 mm         -               -

Machinery:
   Oil fired boilers, steam turbines,
   Direct drive, 2 shafts, 34,000 shp / 25,364 Kw = 29.21 kts
   Range 3,500nm at 10.00 kts
   Bunker at max displacement = 329 tons

Complement:
   216 - 282

Cost:
   £0.337 million / $1.349 million

Distribution of weights at normal displacement:
   Armament: 9 tons, 0.3 %
      - Guns: 9 tons, 0.3 %
   Armour: 4 tons, 0.1 %
      - Armament: 4 tons, 0.1 %
   Machinery: 1,628 tons, 49.5 %
   Hull, fittings & equipment: 1,015 tons, 30.8 %
   Fuel, ammunition & stores: 256 tons, 7.8 %
   Miscellaneous weights: 380 tons, 11.5 %
      - Hull below water: 160 tons
      - Hull above water: 160 tons
      - On freeboard deck: 45 tons
      - Above deck: 15 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     1,445 lbs / 655 Kg = 47.4 x 3.9 " / 100 mm shells or 0.4 torpedoes
   Stability (Unstable if below 1.00): 1.51
   Metacentric height 2.8 ft / 0.9 m
   Roll period: 10.7 seconds
   Steadiness   - As gun platform (Average = 50 %): 53 %
         - Recoil effect (Restricted arc if above 1.00): 0.02
   Seaboat quality  (Average = 1.00): 1.09

Hull form characteristics:
   Hull has rise forward of midbreak,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.472 / 0.478
   Length to Beam Ratio: 9.62 : 1
   'Natural speed' for length: 20.25 kts
   Power going to wave formation at top speed: 60 %
   Trim (Max stability = 0, Max steadiness = 100): 49
   Bow angle (Positive = bow angles forward): 20.00 degrees
   Stern overhang: 5.05 ft / 1.54 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
      - Forecastle:   20.00 %,  22.15 ft / 6.75 m,  22.15 ft / 6.75 m
      - Forward deck:   20.00 %,  22.15 ft / 6.75 m,  22.15 ft / 6.75 m
      - Aft deck:   45.00 %,  9.84 ft / 3.00 m,  9.84 ft / 3.00 m
      - Quarter deck:   15.00 %,  9.84 ft / 3.00 m,  9.84 ft / 3.00 m
      - Average freeboard:      14.76 ft / 4.50 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 171.3 %
      - Above water (accommodation/working, high = better): 136.7 %
   Waterplane Area: 11,371 Square feet or 1,056 Square metres
   Displacement factor (Displacement / loading): 86 %
   Structure weight / hull surface area: 55 lbs/sq ft or 266 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.86
      - Longitudinal: 1.34
      - Overall: 0.90
   Cramped machinery, storage, compartmentation space
   Excellent accommodation and workspace room

Removed following items:
--4x140L50 guns
--2x75L50 guns
--All MISC items

Add following (Both)
--One twin 100mm gun mount
--Four single 6.5mm MG mounts
--Add 300t MISC Weight

Airgroup Calc
Waterplane: 1670.81
Max Airgroup: 25
Reduced for Flightdeck Cruiser status: 12

Max Weight 960
Adjusted for Conversion 1440
Avalible MISC Wieght : 320
Max Airgroup: 2 (320t)

Misc Weight Distribution
-Below Water (160t)
--160t Airgroup
-Above Water (160t)
--160t Airgroup
-On Deck (45t)
--30t Flying Off Deck Reinforcement
--1t 1912 Fire Control
--10t Short Range Wireless
--4t Construction Reserve
-Above Deck (15t)
--5t Additional Optical Spotting Equipment
--5t Flying Off Deck Managment Equipment
--5t Improved Signaling Equipment