Interesting Ship Concepts

[Carthaginian]

Something I've been playing with... what is the smallest EFFECTIVE 18" "treaty battleship" one can design. I basically wanted to hybridize the Yamato and the South Dakota, to try and come up with a ship with 18" guns that a nation could produce in effective numbers. I'm aware that she'd probably be less effective than a ship on equal tonnage with equal protection and 8-9 16" guns... but it was fun to try and trim her down!

Maybe next I will play with something in the 20" range (though she'd be a treaty-buster) for similar effect!

Treaty Study #1, 18" Battleship laid down 1932

Displacement:
   33,295 t light; 35,250 t standard; 36,400 t normal; 37,320 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (700.00 ft / 700.00 ft) x 100.00 ft x (28.00 / 28.60 ft)
   (213.36 m / 213.36 m) x 30.48 m  x (8.53 / 8.72 m)

Armament:
      6 - 18.00" / 457 mm 40.0 cal guns - 3,000.01lbs / 1,360.78kg shells, 100 per gun
     Breech loading guns in turret on barbette mounts, 1932 Model
     3 x Twin mounts on centreline ends, majority forward
      1 raised mount - superfiring
      12 - 6.00" / 152 mm 45.0 cal guns - 100.00lbs / 45.36kg shells, 250 per gun
     Breech loading guns in turret on barbette mounts, 1932 Model
     6 x Twin mounts on sides, evenly spread
      8 - 3.00" / 76.2 mm 50.0 cal guns - 14.99lbs / 6.80kg shells, 600 per gun
     Anti-air guns in deck mounts, 1932 Model
     8 x Single mounts on sides, evenly spread
      8 raised mounts
      16 - 1.50" / 38.1 mm 60.0 cal guns - 1.50lbs / 0.68kg shells, 1,500 per gun
     Breech loading guns in deck mounts, 1932 Model
     8 x Twin mounts on sides, evenly spread
      8 raised mounts
      Weight of broadside 19,344 lbs / 8,774 kg

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   12.0" / 305 mm   425.00 ft / 129.54 m   16.00 ft / 4.88 m
   Ends:   Unarmoured
     Main Belt covers 93 % of normal length

   - Torpedo Bulkhead - Additional damage containing bulkheads:
      2.00" / 51 mm   425.00 ft / 129.54 m   36.00 ft / 10.97 m
   Beam between torpedo bulkheads 90.00 ft / 27.43 m

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   14.0" / 356 mm   8.00" / 203 mm      12.0" / 305 mm
   2nd:   4.00" / 102 mm   4.00" / 102 mm      4.00" / 102 mm
   3rd:   0.50" / 13 mm         -               -

   - Armoured deck - multiple decks:
   For and Aft decks: 5.00" / 127 mm

   - Conning towers: Forward 12.00" / 305 mm, Aft 0.00" / 0 mm

Machinery:
   Oil fired boilers, steam turbines,
   Geared drive, 4 shafts, 100,000 shp / 74,600 Kw = 27.00 kts
   Range 6,060nm at 12.00 kts
   Bunker at max displacement = 2,070 tons

Complement:
   1,316 - 1,712

Cost:
   £14.090 million / $56.358 million

Distribution of weights at normal displacement:
   Armament: 2,635 tons, 7.2 %
      - Guns: 2,635 tons, 7.2 %
   Armour: 12,297 tons, 33.8 %
      - Belts: 3,584 tons, 9.8 %
      - Torpedo bulkhead: 1,132 tons, 3.1 %
      - Armament: 3,447 tons, 9.5 %
      - Armour Deck: 3,849 tons, 10.6 %
      - Conning Tower: 284 tons, 0.8 %
   Machinery: 2,952 tons, 8.1 %
   Hull, fittings & equipment: 14,962 tons, 41.1 %
   Fuel, ammunition & stores: 3,105 tons, 8.5 %
   Miscellaneous weights: 450 tons, 1.2 %
      - Hull below water: 200 tons
      - Hull above water: 200 tons
      - On freeboard deck: 50 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     61,688 lbs / 27,981 Kg = 21.2 x 18.0 " / 457 mm shells or 9.7 torpedoes
   Stability (Unstable if below 1.00): 1.20
   Metacentric height 7.0 ft / 2.1 m
   Roll period: 15.9 seconds
   Steadiness   - As gun platform (Average = 50 %): 51 %
         - Recoil effect (Restricted arc if above 1.00): 0.87
   Seaboat quality  (Average = 1.00): 1.24

Hull form characteristics:
   Hull has low quarterdeck ,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.650 / 0.652
   Length to Beam Ratio: 7.00 : 1
   'Natural speed' for length: 26.46 kts
   Power going to wave formation at top speed: 52 %
   Trim (Max stability = 0, Max steadiness = 100): 41
   Bow angle (Positive = bow angles forward): 0.00 degrees
   Stern overhang: 0.00 ft / 0.00 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
      - Forecastle:   20.00 %,  32.00 ft / 9.75 m,  27.00 ft / 8.23 m
      - Forward deck:   30.00 %,  27.00 ft / 8.23 m,  25.00 ft / 7.62 m
      - Aft deck:   30.00 %,  25.00 ft / 7.62 m,  24.00 ft / 7.32 m
      - Quarter deck:   20.00 %,  16.00 ft / 4.88 m,  16.00 ft / 4.88 m
      - Average freeboard:      24.15 ft / 7.36 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 74.0 %
      - Above water (accommodation/working, high = better): 196.0 %
   Waterplane Area: 53,624 Square feet or 4,982 Square metres
   Displacement factor (Displacement / loading): 110 %
   Structure weight / hull surface area: 213 lbs/sq ft or 1,038 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.95
      - Longitudinal: 1.62
      - Overall: 1.00
   Excellent machinery, storage, compartmentation space
   Excellent accommodation and workspace room
   Good seaboat, rides out heavy weather easily