CSA 15" Battleships studies

[Guinness]

Two reasonably well fleshed out studies. Both limited to 30,000 tons (light). One fast, one slower but better armed and protected. Which one would you build?

1914BB 1912 engines 25 knots, CSA Battleship laid down 1914 (Engine 1912)

Displacement:
   30,000 t light; 32,036 t standard; 33,910 t normal; 35,409 t full load

Dimensions: Length overall / water x beam x draught
   670.00 ft / 660.00 ft x 98.00 ft x 31.64 ft (normal load)
   204.22 m / 201.17 m x 29.87 m  x 9.64 m

Armament:
      8 - 15.00" / 381 mm guns (4x2 guns), 2,000.00lbs / 907.18kg shells, 1914 Model
     Breech loading guns in turrets (on barbettes)
     on centreline, evenly spread, 2 raised mounts
     Aft Main mounts separated by engine room
      14 - 5.50" / 140 mm guns in single mounts, 75.00lbs / 34.02kg shells, 1914 Model
     Breech loading guns in casemate mounts
     on side, all amidships
      10 - 1.00" / 25.4 mm guns (5x2 guns), 0.50lbs / 0.23kg shells, 1914 Model
     Anti-aircraft guns in deck mounts
     on side, evenly spread, all raised mounts
      8 - 3.50" / 88.9 mm guns in single mounts, 20.00lbs / 9.07kg shells, 1914 Model
     Quick firing guns in deck mounts with hoists
     on side, all amidships, all raised mounts - superfiring
   Weight of broadside 17,215 lbs / 7,809 kg
   Shells per gun, main battery: 140

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   13.5" / 343 mm   430.00 ft / 131.06 m   15.00 ft / 4.57 m
   Ends:   4.00" / 102 mm   210.00 ft / 64.01 m   10.00 ft / 3.05 m
     20.00 ft / 6.10 m Unarmoured ends
   Upper:   4.00" / 102 mm   430.00 ft / 131.06 m   12.00 ft / 3.66 m
     Main Belt covers 100 % of normal length

   - Torpedo Bulkhead:
      2.00" / 51 mm   430.00 ft / 131.06 m   24.00 ft / 7.32 m

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   15.0" / 381 mm   6.00" / 152 mm      14.0" / 356 mm
   2nd:   4.00" / 102 mm   4.00" / 102 mm      3.00" / 76 mm
   4th:         -      1.00" / 25 mm            -
   5th:   2.00" / 51 mm         -         2.00" / 51 mm

   - Armour deck: 3.50" / 89 mm, Conning tower: 14.00" / 356 mm

Machinery:
   Oil fired boilers, steam turbines,
   Direct drive, 4 shafts, 70,000 shp / 52,220 Kw = 25.00 kts
   Range 7,400nm at 12.00 kts
   Bunker at max displacement = 3,372 tons

Complement:
   1,249 - 1,624

Cost:
   £3.817 million / $15.268 million

Distribution of weights at normal displacement:
   Armament: 1,855 tons, 5.5 %
   Armour: 12,191 tons, 36.0 %
      - Belts: 4,990 tons, 14.7 %
      - Torpedo bulkhead: 764 tons, 2.3 %
      - Armament: 3,116 tons, 9.2 %
      - Armour Deck: 3,006 tons, 8.9 %
      - Conning Tower: 316 tons, 0.9 %
   Machinery: 2,791 tons, 8.2 %
   Hull, fittings & equipment: 12,763 tons, 37.6 %
   Fuel, ammunition & stores: 3,910 tons, 11.5 %
   Miscellaneous weights: 400 tons, 1.2 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     43,527 lbs / 19,743 Kg = 25.8 x 15.0 " / 381 mm shells or 6.8 torpedoes
   Stability (Unstable if below 1.00): 1.10
   Metacentric height 5.8 ft / 1.8 m
   Roll period: 17.1 seconds
   Steadiness   - As gun platform (Average = 50 %): 52 %
         - Recoil effect (Restricted arc if above 1.00): 0.70
   Seaboat quality  (Average = 1.00): 1.21

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0.580
   Length to Beam Ratio: 6.73 : 1
   'Natural speed' for length: 25.69 kts
   Power going to wave formation at top speed: 49 %
   Trim (Max stability = 0, Max steadiness = 100): 43
   Bow angle (Positive = bow angles forward): 21.80 degrees
   Stern overhang: 0.00 ft / 0.00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      25.00 ft / 7.62 m
      - Forecastle (20 %):   23.00 ft / 7.01 m
      - Mid (50 %):      18.00 ft / 5.49 m
      - Quarterdeck (20 %):   18.00 ft / 5.49 m
      - Stern:      18.00 ft / 5.49 m
      - Average freeboard:   19.91 ft / 6.07 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 89.4 %
      - Above water (accommodation/working, high = better): 136.3 %
   Waterplane Area: 46,428 Square feet or 4,313 Square metres
   Displacement factor (Displacement / loading): 103 %
   Structure weight / hull surface area: 196 lbs/sq ft or 958 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.95
      - Longitudinal: 1.48
      - 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

Misc Weights:
250 t Fire Control
25 t Marconi
10 t Marconi
65 t Flag Facilities
50 t Reserve

-----------------------------------------------------------------------------------------

1914BB 1912 engines 21 knots 10 guns, CSA Battleship laid down 1914 (Engine 1912)

Displacement:
   30,000 t light; 32,293 t standard; 34,164 t normal; 35,662 t full load

Dimensions: Length overall / water x beam x draught
   615.00 ft / 605.00 ft x 100.00 ft x 31.67 ft (normal load)
   187.45 m / 184.40 m x 30.48 m  x 9.65 m

Armament:
      10 - 15.00" / 381 mm guns (5x2 guns), 2,000.00lbs / 907.18kg shells, 1914 Model
     Breech loading guns in turrets (on barbettes)
     on centreline ends, majority aft, 2 raised mounts - superfiring
      14 - 5.50" / 140 mm guns in single mounts, 75.00lbs / 34.02kg shells, 1914 Model
     Breech loading guns in casemate mounts
     on side, all amidships
      10 - 1.00" / 25.4 mm guns (5x2 guns), 0.50lbs / 0.23kg shells, 1914 Model
     Anti-aircraft guns in deck mounts
     on side, evenly spread, all raised mounts
      8 - 3.50" / 88.9 mm guns in single mounts, 20.00lbs / 9.07kg shells, 1914 Model
     Quick firing guns in deck mounts with hoists
     on side, all amidships, all raised mounts - superfiring
   Weight of broadside 21,215 lbs / 9,623 kg
   Shells per gun, main battery: 135

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   14.0" / 356 mm   395.00 ft / 120.40 m   16.00 ft / 4.88 m
   Ends:   4.00" / 102 mm   190.00 ft / 57.91 m   10.00 ft / 3.05 m
     20.00 ft / 6.10 m Unarmoured ends
   Upper:   5.00" / 127 mm   395.00 ft / 120.40 m   12.00 ft / 3.66 m
     Main Belt covers 100 % of normal length

   - Torpedo Bulkhead:
      2.00" / 51 mm   395.00 ft / 120.40 m   24.00 ft / 7.32 m

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   15.0" / 381 mm   6.00" / 152 mm      14.0" / 356 mm
   2nd:   5.00" / 127 mm   5.00" / 127 mm      3.00" / 76 mm
   4th:         -      1.00" / 25 mm            -
   5th:   2.00" / 51 mm         -         3.00" / 76 mm

   - Armour deck: 4.00" / 102 mm, Conning tower: 15.00" / 381 mm

Machinery:
   Oil fired boilers, steam turbines,
   Direct drive, 2 shafts, 35,000 shp / 26,110 Kw = 20.56 kts
   Range 7,400nm at 12.00 kts
   Bunker at max displacement = 3,369 tons

Complement:
   1,256 - 1,633

Cost:
   £4.019 million / $16.077 million

Distribution of weights at normal displacement:
   Armament: 2,277 tons, 6.7 %
   Armour: 13,378 tons, 39.2 %
      - Belts: 5,226 tons, 15.3 %
      - Torpedo bulkhead: 702 tons, 2.1 %
      - Armament: 3,762 tons, 11.0 %
      - Armour Deck: 3,348 tons, 9.8 %
      - Conning Tower: 340 tons, 1.0 %
   Machinery: 1,396 tons, 4.1 %
   Hull, fittings & equipment: 12,550 tons, 36.7 %
   Fuel, ammunition & stores: 4,164 tons, 12.2 %
   Miscellaneous weights: 400 tons, 1.2 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     44,615 lbs / 20,237 Kg = 26.4 x 15.0 " / 381 mm shells or 7.4 torpedoes
   Stability (Unstable if below 1.00): 1.10
   Metacentric height 6.0 ft / 1.8 m
   Roll period: 17.2 seconds
   Steadiness   - As gun platform (Average = 50 %): 52 %
         - Recoil effect (Restricted arc if above 1.00): 0.73
   Seaboat quality  (Average = 1.00): 1.35

Hull form characteristics:
   Hull has a flush deck
   Block coefficient: 0.624
   Length to Beam Ratio: 6.05 : 1
   'Natural speed' for length: 24.60 kts
   Power going to wave formation at top speed: 43 %
   Trim (Max stability = 0, Max steadiness = 100): 39
   Bow angle (Positive = bow angles forward): 23.50 degrees
   Stern overhang: 0.00 ft / 0.00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      23.00 ft / 7.01 m
      - Forecastle (20 %):   21.00 ft / 6.40 m
      - Mid (40 %):      17.00 ft / 5.18 m
      - Quarterdeck (20 %):   17.00 ft / 5.18 m
      - Stern:      17.00 ft / 5.18 m
      - Average freeboard:   18.36 ft / 5.60 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 83.5 %
      - Above water (accommodation/working, high = better): 121.2 %
   Waterplane Area: 45,248 Square feet or 4,204 Square metres
   Displacement factor (Displacement / loading): 98 %
   Structure weight / hull surface area: 204 lbs/sq ft or 996 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.95
      - Longitudinal: 1.56
      - 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

Misc Weights:
250 t Fire Control
25 t Marconi
10 t Marconi
65 t Flag Facilities
50 t Reserve

[Borys]

I'd prefer better gunnery from either ...
Otherwise quite immpressive, although I'm a bit worried about 4" UB.
Borys

[Guinness]

Yeah, the 4" UB is a compromise, but I also see it as an evolutionary step toward AON protection. Really in a 15" gunned and bigger world, a UB has just about stopped making sense (which is of course why the concept of AON came about). I can give the fast design a 5" UB (as well as 5" casemate faces and surrounding armor) at the price of .25" of armored deck, which might be a worthwhile compromise.

Somewhere around 15% steadiness is the price of superimposing 15" twin turrets. I can live with that. I think average steadiness is a good enough gun platform. The difference in roll period either way is only about 1 second.

[Borys]

True 'bout the Fire Platform - my 70% designs have a 17,1 second roll.
:)

As concerns the UB -  it was knee-jerk reaction from me. I was thinking about the 8"-10" Second Calibre Main Guns of the latest PDNs. Or longer range 12" fire.

Hmm - a 3"-4" plate keeps out the 6" guns, which everybody here has on their battelships by the spade.

Maybe I should rethink my design phylosophy ...

Borys