A GB/CA/1921 design

This is another attempt at a fast, British 1921-style heavy armoured cruiser. The ship has 9-10in/50, 16-5.5in/50 QF, 6-4.7in AA, and 24-2pdr AA guns. The armour basis is 8in. This is the Springsharp report:

GB/CA/1921, Great Britain Armoured Cruiser laid down 1921 (Engine 1937)

Displacement:
 24,231 t light; 25,234 t standard; 26,899 t normal; 28,230 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
 (760.07 ft / 755.00 ft) x 88.00 ft x (26.00 / 26.99 ft)
 (231.67 m / 230.12 m) x 26.82 m  x (7.92 / 8.23 m)

Armament:
      9 - 10.00" / 254 mm 50.0 cal guns - 529.32lbs / 240.10kg shells, 120 per gun
   Breech loading guns in turret on barbette mounts, 1921 Model
   3 x Triple mounts on centreline ends, majority forward
  1 raised mount - superfiring
      16 - 5.50" / 140 mm 50.0 cal guns - 88.07lbs / 39.95kg shells, 150 per gun
   Quick firing guns in turret on barbette mounts, 1921 Model
   8 x Twin mounts on sides, aft deck forward
  4 raised mounts - superfiring
      6 - 4.70" / 119 mm 45.0 cal guns - 52.35lbs / 23.75kg shells, 150 per gun
   Anti-air guns in deck and hoist mounts, 1921 Model
   6 x Single mounts on sides, forward deck aft
  6 raised mounts
      24 - 1.57" / 40.0 mm 45.0 cal guns - 1.97lbs / 0.89kg shells, 150 per gun
   Anti-air guns in deck mounts, 1921 Model
   6 x 2 row quad mounts on sides, evenly spread
  6 raised mounts
      Weight of broadside 6,534 lbs / 2,964 kg

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 8.00" / 203 mm 435.00 ft / 132.59 m 16.00 ft / 4.88 m
 Ends: Unarmoured
   Main Belt covers 89 % of normal length
   Main belt does not fully cover magazines and engineering spaces

   - Torpedo Bulkhead:
  1.00" / 25 mm 435.00 ft / 132.59 m 26.00 ft / 7.92 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 9.00" / 229 mm 6.00" / 152 mm  9.00" / 229 mm
 2nd: 4.00" / 102 mm 3.00" / 76 mm  4.00" / 102 mm

   - Armoured deck - multiple decks: 3.00" / 76 mm For and Aft decks
 Forecastle: 3.00" / 76 mm  Quarter deck: 3.00" / 76 mm

   - Conning towers: Forward 8.00" / 203 mm,  Aft 0.00" / 0 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 4 shafts, 173,434 shp / 129,382 Kw = 34.00 kts
 Range 5,400nm at 17.00 kts
 Bunker at max displacement = 2,996 tons

Complement:
 1,049 - 1,365

Cost:
 £5.593 million / $22.373 million

Distribution of weights at normal displacement:
 Armament: 1,632 tons, 6.1 %
 Armour: 7,509 tons, 27.9 %
    - Belts: 2,386 tons, 8.9 %
    - Torpedo bulkhead: 418 tons, 1.6 %
    - Armament: 1,904 tons, 7.1 %
    - Armour Deck: 2,646 tons, 9.8 %
    - Conning Tower: 155 tons, 0.6 %
 Machinery: 4,807 tons, 17.9 %
 Hull, fittings & equipment: 10,284 tons, 38.2 %
 Fuel, ammunition & stores: 2,668 tons, 9.9 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   39,909 lbs / 18,103 Kg = 79.8 x 10.0 " / 254 mm shells or 4.9 torpedoes
 Stability (Unstable if below 1.00): 1.11
 Metacentric height 5.0 ft / 1.5 m
 Roll period: 16.4 seconds
 Steadiness - As gun platform (Average = 50 %): 54 %
   - Recoil effect (Restricted arc if above 1.00): 0.53
 Seaboat quality  (Average = 1.00): 1.08

Hull form characteristics:
 Hull has a flush deck,
   an extended bulbous bow and small transom stern
 Block coefficient (normal/deep): 0.545 / 0.551
 Length to Beam Ratio: 8.58 : 1
 'Natural speed' for length: 29.60 kts
 Power going to wave formation at top speed: 57 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): 9.00 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,  28.00 ft / 8.53 m
    - Forward deck: 30.00 %,  28.00 ft / 8.53 m,  25.00 ft / 7.62 m
    - Aft deck: 35.00 %,  25.00 ft / 7.62 m,  25.00 ft / 7.62 m
    - Quarter deck: 15.00 %,  25.00 ft / 7.62 m,  25.00 ft / 7.62 m
    - Average freeboard:  26.37 ft / 8.04 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 105.3 %
  - Above water (accommodation/working, high = better): 220.6 %
 Waterplane Area: 47,286 Square feet or 4,393 Square metres
 Displacement factor (Displacement / loading): 114 %
 Structure weight / hull surface area: 159 lbs/sq ft or 775 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.97
  - Longitudinal: 1.34
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is adequate
 Room for accommodation and workspaces is excellent

I was interested to read about A.P. Tulley's research

John W. Fox, on the NavWarGames Yahoo Group, pointed out a good article by A.P. Tulley about how the mystery surrounding the loss of the Japanese battleship Kongo was solved. My research is about the 1650's and the Dutch navy, but I can relate to Tully's persistence in solving the mystery about the Kongo's loss. Not many writers even realized that there was a mystery.

A Belted Cruiser: the GB/CA/1905

I have been thinking a lot about 1880's design standards. One thread of development in that period were belted cruisers. They had a relatively thick, but narrow belt of armour. That was the main protection, although there would have been some deck armour, as well. My design has 8-9.2in/50 BLR and 16-4in QF guns. The belt is just 10ft wide, but is 8in thick. The speed is a more modern 25 knots. This is the Springsharp report:

GB/CA/1905, Great Britain Belted Cruiser laid down 1905 (Engine 1910)

Displacement:
 10,209 t light; 10,764 t standard; 12,948 t normal; 14,694 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
 (492.00 ft / 485.00 ft) x 65.00 ft x (25.00 / 27.71 ft)
 (149.96 m / 147.83 m) x 19.81 m  x (7.62 / 8.45 m)

Armament:
      8 - 9.20" / 234 mm 50.0 cal guns - 380.00lbs / 172.37kg shells, 150 per gun
   Breech loading guns in turret on barbette mounts, 1905 Model
   2 x Twin mounts on centreline ends, evenly spread
   2 x Twin mounts on sides amidships
   Aft Main mounts separated by engine room
      16 - 4.00" / 102 mm 45.0 cal guns - 32.00lbs / 14.51kg shells, 150 per gun
   Quick firing guns in casemate mounts, 1905 Model
   16 x Single mounts on sides amidships
  8 raised mounts
      Weight of broadside 3,552 lbs / 1,611 kg

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 8.00" / 203 mm 390.00 ft / 118.87 m 10.00 ft / 3.05 m
 Ends: Unarmoured
   Main Belt covers 124 % of normal length

   - Torpedo Bulkhead:
  1.00" / 25 mm 390.00 ft / 118.87 m 25.00 ft / 7.62 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 7.00" / 178 mm 4.00" / 102 mm  6.00" / 152 mm
 2nd: 4.00" / 102 mm 4.00" / 102 mm  4.00" / 102 mm

   - Armoured deck - multiple decks: 2.00" / 51 mm For and Aft decks
 Forecastle: 2.00" / 51 mm  Quarter deck: 2.00" / 51 mm

   - Conning towers: Forward 5.00" / 127 mm,  Aft 0.00" / 0 mm

Machinery:
 Coal fired boilers, steam turbines, 
 Direct drive, 4 shafts, 42,596 shp / 31,776 Kw = 25.00 kts
 Range 5,400nm at 16.00 kts
 Bunker at max displacement = 3,930 tons (100% coal)

Complement:
 606 - 788

Cost:
 £0.996 million / $3.985 million

Distribution of weights at normal displacement:
 Armament: 909 tons, 7.0 %
 Armour: 3,453 tons, 26.7 %
    - Belts: 1,275 tons, 9.8 %
    - Torpedo bulkhead: 361 tons, 2.8 %
    - Armament: 919 tons, 7.1 %
    - Armour Deck: 838 tons, 6.5 %
    - Conning Tower: 59 tons, 0.5 %
 Machinery: 1,936 tons, 15.0 %
 Hull, fittings & equipment: 3,912 tons, 30.2 %
 Fuel, ammunition & stores: 2,738 tons, 21.1 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   20,351 lbs / 9,231 Kg = 52.3 x 9.2 " / 234 mm shells or 3.1 torpedoes
 Stability (Unstable if below 1.00): 1.17
 Metacentric height 3.5 ft / 1.1 m
 Roll period: 14.6 seconds
 Steadiness - As gun platform (Average = 50 %): 69 %
   - Recoil effect (Restricted arc if above 1.00): 0.76
 Seaboat quality  (Average = 1.00): 1.37

Hull form characteristics:
 Hull has low quarterdeck ,
   a ram bow and a cruiser stern
 Block coefficient (normal/deep): 0.575 / 0.589
 Length to Beam Ratio: 7.46 : 1
 'Natural speed' for length: 22.02 kts
 Power going to wave formation at top speed: 55 %
 Trim (Max stability = 0, Max steadiness = 100): 50
 Bow angle (Positive = bow angles forward): -3.00 degrees
 Stern overhang: -2.00 ft / -0.61 m
 Freeboard (% = length of deck as a percentage of waterline length):
    Fore end,  Aft end
    - Forecastle: 25.00 %,  26.00 ft / 7.92 m,  24.00 ft / 7.32 m
    - Forward deck: 30.00 %,  24.00 ft / 7.32 m,  24.00 ft / 7.32 m
    - Aft deck: 13.00 %,  24.00 ft / 7.32 m,  24.00 ft / 7.32 m
    - Quarter deck: 32.00 %,  16.00 ft / 4.88 m,  16.00 ft / 4.88 m
    - Average freeboard:  21.64 ft / 6.60 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 108.8 %
  - Above water (accommodation/working, high = better): 169.9 %
 Waterplane Area: 22,523 Square feet or 2,092 Square metres
 Displacement factor (Displacement / loading): 120 %
 Structure weight / hull surface area: 119 lbs/sq ft or 583 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.92
  - Longitudinal: 2.19
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is adequate
 Room for accommodation and workspaces is excellent
 Good seaboat, rides out heavy weather easily

A fast Italian cruiser: It/CL/1942

I wanted my 1942 Italian light cruiser to be pretty fast, but to have some protection. I wanted more than the Capitani Romani class. I have 9-5.3in DP guns, 8-57mm AA guns, 12-37mm AA guns, and 8-21in TT. The speed is 37 knots. The ship can theoretically survive one torpedo hit. This is the Springsharp report:

It/CL/1942, Italy Light Cruiser laid down 1942 (Engine 1950)

Displacement:
 7,691 t light; 7,935 t standard; 8,604 t normal; 9,139 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
 (586.59 ft / 580.00 ft) x 55.00 ft x (20.00 / 20.87 ft)
 (178.79 m / 176.78 m) x 16.76 m  x (6.10 / 6.36 m)

Armament:
      9 - 5.30" / 135 mm 50.0 cal guns - 78.00lbs / 35.38kg shells, 150 per gun
   Dual purpose guns in turret on barbette mounts, 1942 Model
   3 x Triple mounts on centreline ends, majority forward
  1 raised mount - superfiring
      8 - 2.24" / 57.0 mm 70.0 cal guns - 6.00lbs / 2.72kg shells, 0 per gun
   Anti-air guns in deck and hoist mounts, 1942 Model
   4 x Twin mounts on sides, forward deck aft
  4 raised mounts
      12 - 1.46" / 37.0 mm 70.0 cal guns - 1.75lbs / 0.79kg shells, 150 per gun
   Breech loading guns in deck mounts, 1942 Model
   6 x Twin mounts on sides, aft deck forward
  6 raised mounts
      Weight of broadside 771 lbs / 350 kg
      8 - 21.0" / 533 mm, 22.00 ft / 6.71 m torpedoes - 1.509 t each, 12.073 t total
 In 2 sets of deck mounted side rotating tubes

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 2.00" / 51 mm 380.00 ft / 115.82 m 12.00 ft / 3.66 m
 Ends: Unarmoured
   Main Belt covers 101 % of normal length
   Main belt does not fully cover magazines and engineering spaces

   - Torpedo Bulkhead:
  0.60" / 15 mm 380.00 ft / 115.82 m 20.00 ft / 6.10 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 2.00" / 51 mm 1.00" / 25 mm  2.00" / 51 mm

   - Armoured deck - single deck: 1.00" / 25 mm For and Aft decks
 Forecastle: 1.00" / 25 mm  Quarter deck: 1.00" / 25 mm

   - Conning towers: Forward 2.00" / 51 mm,  Aft 0.00" / 0 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 4 shafts, 117,970 shp / 88,006 Kw = 37.00 kts
 Range 5,400nm at 16.00 kts
 Bunker at max displacement = 1,204 tons

Complement:
 446 - 580

Cost:
 £4.771 million / $19.084 million

Distribution of weights at normal displacement:
 Armament: 231 tons, 2.7 %
    - Guns: 219 tons, 2.5 %
    - Torpedoes: 12 tons, 0.1 %
 Armour: 1,077 tons, 12.5 %
    - Belts: 372 tons, 4.3 %
    - Torpedo bulkhead: 169 tons, 2.0 %
    - Armament: 116 tons, 1.3 %
    - Armour Deck: 402 tons, 4.7 %
    - Conning Tower: 18 tons, 0.2 %
 Machinery: 2,822 tons, 32.8 %
 Hull, fittings & equipment: 3,561 tons, 41.4 %
 Fuel, ammunition & stores: 913 tons, 10.6 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   8,846 lbs / 4,012 Kg = 118.8 x 5.3 " / 135 mm shells or 1.3 torpedoes
 Stability (Unstable if below 1.00): 1.15
 Metacentric height 2.6 ft / 0.8 m
 Roll period: 14.2 seconds
 Steadiness - As gun platform (Average = 50 %): 54 %
   - Recoil effect (Restricted arc if above 1.00): 0.31
 Seaboat quality  (Average = 1.00): 1.10

Hull form characteristics:
 Hull has a flush deck,
   an extended bulbous bow and large transom stern
 Block coefficient (normal/deep): 0.472 / 0.480
 Length to Beam Ratio: 10.55 : 1
 'Natural speed' for length: 27.46 kts
 Power going to wave formation at top speed: 62 %
 Trim (Max stability = 0, Max steadiness = 100): 49
 Bow angle (Positive = bow angles forward): 9.00 degrees
 Stern overhang: 2.00 ft / 0.61 m
 Freeboard (% = length of deck as a percentage of waterline length):
    Fore end,  Aft end
    - Forecastle: 20.00 %,  29.00 ft / 8.84 m,  25.00 ft / 7.62 m
    - Forward deck: 30.00 %,  25.00 ft / 7.62 m,  22.00 ft / 6.71 m
    - Aft deck: 34.00 %,  22.00 ft / 6.71 m,  19.00 ft / 5.79 m
    - Quarter deck: 16.00 %,  19.00 ft / 5.79 m,  19.00 ft / 5.79 m
    - Average freeboard:  22.38 ft / 6.82 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 181.7 %
  - Above water (accommodation/working, high = better): 196.6 %
 Waterplane Area: 21,544 Square feet or 2,001 Square metres
 Displacement factor (Displacement / loading): 114 %
 Structure weight / hull surface area: 94 lbs/sq ft or 457 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.92
  - Longitudinal: 2.17
  - Overall: 1.00
 Hull space for machinery, storage, compartmentation is cramped
 Room for accommodation and workspaces is excellent

An Atlanta-style light cruiser

I wanted to see what an Atlanta-style fast light cruiser would be like. I call my design the "US/CL/1940 AA". My ship has 16-5in/38 DP guns and has a 34 knot speed:

US/CL/1940 AA, United States Light Cruiser laid down 1940 (Engine 1950)

Displacement:
 7,687 t light; 7,951 t standard; 8,625 t normal; 9,165 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
 (546.43 ft / 540.00 ft) x 54.00 ft x (20.50 / 21.43 ft)
 (166.55 m / 164.59 m) x 16.46 m  x (6.25 / 6.53 m)

Armament:
      12 - 5.00" / 127 mm 38.0 cal guns - 58.00lbs / 26.31kg shells, 150 per gun
   Dual purpose guns in turret on barbette mounts, 1940 Model
   4 x Twin mounts on centreline ends, evenly spread
  2 raised mounts - superfiring
   4 x Twin mounts on centreline ends, evenly spread
  4 double raised mounts
      4 - 5.00" / 127 mm 38.0 cal guns - 58.00lbs / 26.31kg shells, 150 per gun
   Dual purpose guns in turret on barbette mounts, 1940 Model
   2 x Twin mounts on sides, forward deck aft
      12 - 1.57" / 40.0 mm 45.0 cal guns - 2.00lbs / 0.91kg shells, 150 per gun
   Breech loading guns in deck mounts, 1940 Model
   2 x Quad mounts on sides, aft deck forward
  2 raised mounts - superfiring
   1 x Quad mount on centreline, aft deck aft
      Weight of broadside 952 lbs / 432 kg
      8 - 21.0" / 533 mm, 22.00 ft / 6.71 m torpedoes - 1.501 t each, 12.009 t total
 In 2 sets of deck mounted side rotating tubes

Armour:
   - Belts:  Width (max) Length (avg)  Height (avg)
 Main: 4.00" / 102 mm 355.00 ft / 108.20 m 12.00 ft / 3.66 m
 Ends: Unarmoured
   Main Belt covers 101 % of normal length
   Main belt does not fully cover magazines and engineering spaces

   - Torpedo Bulkhead:
  0.60" / 15 mm 355.00 ft / 108.20 m 20.50 ft / 6.25 m

   - Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
 Main: 2.00" / 51 mm 1.00" / 25 mm  2.00" / 51 mm
 2nd: 2.00" / 51 mm 1.00" / 25 mm  2.00" / 51 mm

   - Armoured deck - single deck: 2.00" / 51 mm For and Aft decks
 Forecastle: 2.00" / 51 mm  Quarter deck: 2.00" / 51 mm

   - Conning towers: Forward 5.00" / 127 mm,  Aft 0.00" / 0 mm

Machinery:
 Oil fired boilers, steam turbines, 
 Geared drive, 4 shafts, 88,421 shp / 65,962 Kw = 34.00 kts
 Range 5,400nm at 16.00 kts
 Bunker at max displacement = 1,214 tons

Complement:
 446 - 581

Cost:
 £3.858 million / $15.432 million

Distribution of weights at normal displacement:
 Armament: 214 tons, 2.5 %
    - Guns: 202 tons, 2.3 %
    - Torpedoes: 12 tons, 0.1 %
 Armour: 1,952 tons, 22.6 %
    - Belts: 700 tons, 8.1 %
    - Torpedo bulkhead: 162 tons, 1.9 %
    - Armament: 288 tons, 3.3 %
    - Armour Deck: 757 tons, 8.8 %
    - Conning Tower: 45 tons, 0.5 %
 Machinery: 2,115 tons, 24.5 %
 Hull, fittings & equipment: 3,406 tons, 39.5 %
 Fuel, ammunition & stores: 938 tons, 10.9 %
 Miscellaneous weights: 0 tons, 0.0 %

Overall survivability and seakeeping ability:
 Survivability (Non-critical penetrating hits needed to sink ship):
   11,828 lbs / 5,365 Kg = 189.2 x 5.0 " / 127 mm shells or 1.9 torpedoes
 Stability (Unstable if below 1.00): 1.02
 Metacentric height 2.1 ft / 0.6 m
 Roll period: 15.7 seconds
 Steadiness - As gun platform (Average = 50 %): 51 %
   - Recoil effect (Restricted arc if above 1.00): 0.56
 Seaboat quality  (Average = 1.00): 1.03

Hull form characteristics:
 Hull has a flush deck,
   an extended bulbous bow and large transom stern
 Block coefficient (normal/deep): 0.505 / 0.513
 Length to Beam Ratio: 10.00 : 1
 'Natural speed' for length: 26.50 kts
 Power going to wave formation at top speed: 62 %
 Trim (Max stability = 0, Max steadiness = 100): 49
 Bow angle (Positive = bow angles forward): 9.00 degrees
 Stern overhang: 2.00 ft / 0.61 m
 Freeboard (% = length of deck as a percentage of waterline length):
    Fore end,  Aft end
    - Forecastle: 20.00 %,  28.00 ft / 8.53 m,  24.00 ft / 7.32 m
    - Forward deck: 30.00 %,  24.00 ft / 7.32 m,  21.00 ft / 6.40 m
    - Aft deck: 35.00 %,  21.00 ft / 6.40 m,  18.00 ft / 5.49 m
    - Quarter deck: 15.00 %,  18.00 ft / 5.49 m,  18.00 ft / 5.49 m
    - Average freeboard:  21.40 ft / 6.52 m

Ship space, strength and comments:
 Space - Hull below water (magazines/engines, low = better): 140.9 %
  - Above water (accommodation/working, high = better): 176.3 %
 Waterplane Area: 20,299 Square feet or 1,886 Square metres
 Displacement factor (Displacement / loading): 125 %
 Structure weight / hull surface area: 97 lbs/sq ft or 473 Kg/sq metre
 Hull strength (Relative):
  - Cross-sectional: 0.93
  - Longitudinal: 2.02
  - Overall: 1.01
 Hull space for machinery, storage, compartmentation is cramped
 Room for accommodation and workspaces is excellent