Maximum Twin Turret Armament Study

[Delta Force]

I decided to see what the maximum amount of guns you could carry in twin turrets on a battleship of 35,000 with battlecruiser levels of armor. The designs would be something like an Agincourt.

13.5 Inch Twin Turret Study, CSA Battleship Turret Study laid down 1920

Displacement:
   35,000 t light; 37,713 t standard; 40,244 t normal; 42,270 t full load

Dimensions: Length overall / water x beam x draught
   787.40 ft / 787.40 ft x 104.99 ft (Bulges 111.55 ft) x 28.87 ft (normal load)
   240.00 m / 240.00 m x 32.00 m (Bulges 34.00 m)  x 8.80 m

Armament:
     18 - 13.50" / 343 mm guns (9x2 guns), 1,500.00lbs / 680.39kg shells, 1920 Model
     Breech loading guns in turrets (on barbettes)
     on centreline ends, majority forward, 3 raised mounts - superfiring
     18 - 5.50" / 140 mm guns in single mounts, 75.00lbs / 34.02kg shells, 1920 Model
     Breech loading guns in casemate mounts
     on side, all amidships
     6 - 1.58" / 40.0 mm guns in single mounts, 2.00lbs / 0.91kg shells, 1920 Model
     Breech loading guns in deck mounts
     on centreline ends, evenly spread, all raised mounts - superfiring
   Weight of broadside 28,362 lbs / 12,865 kg
   Shells per gun, main battery: 120

Armour:
  - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   10.0" / 254 mm   510.00 ft / 155.45 m   17.26 ft / 5.26 m
   Ends:   Unarmoured
     Main Belt covers 100 % of normal length

  - Torpedo Bulkhead and Bulges:
      1.50" / 38 mm   510.00 ft / 155.45 m   32.15 ft / 9.80 m

  - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   12.0" / 305 mm   4.00" / 102 mm      10.0" / 254 mm
   2nd:   1.50" / 38 mm         -         3.00" / 76 mm

  - Armour deck: 3.00" / 76 mm, Conning tower: 12.00" / 305 mm

Machinery:
   Oil fired boilers, steam turbines,
   Electric motors, 4 shafts, 54,309 shp / 40,514 Kw = 23.00 kts
   Range 12,000nm at 12.00 kts
   Bunker at max displacement = 4,557 tons

Complement:
   1,419 - 1,846

Cost:
   £9.394 million / $37.576 million

Distribution of weights at normal displacement:
   Armament: 2,957 tons, 7.3 %
   Armour: 12,384 tons, 30.8 %
      - Belts: 3,779 tons, 9.4 %
      - Torpedo bulkhead: 910 tons, 2.3 %
      - Armament: 4,173 tons, 10.4 %
      - Armour Deck: 3,218 tons, 8.0 %
      - Conning Tower: 304 tons, 0.8 %
   Machinery: 1,899 tons, 4.7 %
   Hull, fittings & equipment: 17,361 tons, 43.1 %
   Fuel, ammunition & stores: 5,244 tons, 13.0 %
   Miscellaneous weights: 400 tons, 1.0 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     53,906 lbs / 24,451 Kg = 43.8 x 13.5 " / 343 mm shells or 8.6 torpedoes
   Stability (Unstable if below 1.00): 1.19
   Metacentric height 7.4 ft / 2.2 m
   Roll period: 17.3 seconds
   Steadiness   - As gun platform (Average = 50 %): 50 %
         - Recoil effect (Restricted arc if above 1.00): 0.67
   Seaboat quality  (Average = 1.00): 1.20

Hull form characteristics:
   Hull has raised forecastle
   Block coefficient: 0.555
   Length to Beam Ratio: 7.06 : 1
   'Natural speed' for length: 28.06 kts
   Power going to wave formation at top speed: 38 %
   Trim (Max stability = 0, Max steadiness = 100): 42
   Bow angle (Positive = bow angles forward): 0.00 degrees
   Stern overhang: 0.00 ft / 0.00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      29.53 ft / 9.00 m
      - Forecastle (20 %):   22.97 ft / 7.00 m (19.69 ft / 6.00 m aft of break)
      - Mid (50 %):      19.69 ft / 6.00 m
      - Quarterdeck (15 %):   19.69 ft / 6.00 m
      - Stern:      19.69 ft / 6.00 m
      - Average freeboard:   20.87 ft / 6.36 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 90.6 %
      - Above water (accommodation/working, high = better): 153.2 %
   Waterplane Area: 57,988 Square feet or 5,387 Square metres
   Displacement factor (Displacement / loading): 100 %
   Structure weight / hull surface area: 218 lbs/sq ft or 1,065 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.99
      - Longitudinal: 1.07
      - 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

Main belt armor sloped 20 degrees, giving a vertical height of 16.5 feet. Relative thickness to a 90 degree impact is 10.64 inches.

Misc Weight (400 tons):
250 tons fire control system
25 tons radar
25 tons long range wireless
25 tons night fighting gear
25 tons crane and catapult for floatplane
10 tons 2x floatplanes
40 tons reserve

[Delta Force]

15 Inch Twin Turret Study, CSA Battleship Turret Study laid down 1920

Displacement:
   35,175 t light; 37,959 t standard; 40,502 t normal; 42,535 t full load

Dimensions: Length overall / water x beam x draught
   787.40 ft / 787.40 ft x 104.99 ft (Bulges 111.55 ft) x 28.87 ft (normal load)
   240.00 m / 240.00 m x 32.00 m (Bulges 34.00 m)  x 8.80 m

Armament:
      14 - 15.00" / 381 mm guns (7x2 guns), 2,000.00lbs / 907.18kg shells, 1920 Model
     Breech loading guns in turrets (on barbettes)
     on centreline ends, majority forward, 2 raised mounts - superfiring
      18 - 5.50" / 140 mm guns in single mounts, 75.00lbs / 34.02kg shells, 1920 Model
     Breech loading guns in casemate mounts
     on side, all amidships
      4 - 1.58" / 40.0 mm guns in single mounts, 2.00lbs / 0.91kg shells, 1920 Model
     Breech loading guns in deck mounts
     on centreline ends, evenly spread, all raised mounts - superfiring
   Weight of broadside 29,358 lbs / 13,317 kg
   Shells per gun, main battery: 120

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   10.0" / 254 mm   510.00 ft / 155.45 m   17.26 ft / 5.26 m
   Ends:   Unarmoured
     Main Belt covers 100 % of normal length

   - Torpedo Bulkhead and Bulges:
      1.50" / 38 mm   510.00 ft / 155.45 m   32.15 ft / 9.80 m

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   12.0" / 305 mm   4.00" / 102 mm      10.0" / 254 mm
   2nd:   1.50" / 38 mm         -         3.00" / 76 mm

   - Armour deck: 3.00" / 76 mm, Conning tower: 12.00" / 305 mm

Machinery:
   Oil fired boilers, steam turbines,
   Electric motors, 4 shafts, 54,582 shp / 40,718 Kw = 23.00 kts
   Range 12,000nm at 12.00 kts
   Bunker at max displacement = 4,576 tons

Complement:
   1,426 - 1,855

Cost:
   £9.778 million / $39.113 million

Distribution of weights at normal displacement:
   Armament: 3,141 tons, 7.8 %
   Armour: 11,887 tons, 29.3 %
      - Belts: 3,780 tons, 9.3 %
      - Torpedo bulkhead: 910 tons, 2.2 %
      - Armament: 3,663 tons, 9.0 %
      - Armour Deck: 3,229 tons, 8.0 %
      - Conning Tower: 305 tons, 0.8 %
   Machinery: 1,908 tons, 4.7 %
   Hull, fittings & equipment: 17,839 tons, 44.0 %
   Fuel, ammunition & stores: 5,326 tons, 13.2 %
   Miscellaneous weights: 400 tons, 1.0 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     52,848 lbs / 23,972 Kg = 31.3 x 15.0 " / 381 mm shells or 8.2 torpedoes
   Stability (Unstable if below 1.00): 1.21
   Metacentric height 7.7 ft / 2.3 m
   Roll period: 16.9 seconds
   Steadiness   - As gun platform (Average = 50 %): 50 %
         - Recoil effect (Restricted arc if above 1.00): 0.67
   Seaboat quality  (Average = 1.00): 1.20

Hull form characteristics:
   Hull has raised forecastle
   Block coefficient: 0.559
   Length to Beam Ratio: 7.06 : 1
   'Natural speed' for length: 28.06 kts
   Power going to wave formation at top speed: 38 %
   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 (% = measuring location as a percentage of overall length):
      - Stem:      29.53 ft / 9.00 m
      - Forecastle (20 %):   22.97 ft / 7.00 m (19.69 ft / 6.00 m aft of break)
      - Mid (50 %):      19.69 ft / 6.00 m
      - Quarterdeck (15 %):   19.69 ft / 6.00 m
      - Stern:      19.69 ft / 6.00 m
      - Average freeboard:   20.87 ft / 6.36 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 94.1 %
      - Above water (accommodation/working, high = better): 153.0 %
   Waterplane Area: 58,181 Square feet or 5,405 Square metres
   Displacement factor (Displacement / loading): 98 %
   Structure weight / hull surface area: 224 lbs/sq ft or 1,091 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.99
      - Longitudinal: 1.10
      - Overall: 1.00
   Hull space for machinery, storage, compartmentation is adequate
   Room for accommodation and workspaces is excellent

Main belt armor sloped 20 degrees, giving a vertical height of 16.5 feet. Relative thickness to a 90 degree impact is 10.64 inches.

Misc Weight (400 tons):
250 tons fire control system
25 tons radar
25 tons long range wireless
25 tons night fighting gear
25 tons crane and catapult for floatplane
10 tons 2x floatplanes
40 tons reserve

[Delta Force]

16.5 Inch Twin Turret Study, CSA Battleship Turret Study laid down 1920

Displacement:
   35,350 t light; 37,933 t standard; 40,475 t normal; 42,508 t full load

Dimensions: Length overall / water x beam x draught
   787.40 ft / 787.40 ft x 104.99 ft (Bulges 111.55 ft) x 28.87 ft (normal load)
   240.00 m / 240.00 m x 32.00 m (Bulges 34.00 m)  x 8.80 m

Armament:
      10 - 16.50" / 419 mm guns (5x2 guns), 2,500.00lbs / 1,133.98kg shells, 1920 Model
     Breech loading guns in turrets (on barbettes)
     on centreline ends, majority forward, 2 raised mounts - superfiring
      18 - 5.50" / 140 mm guns in single mounts, 75.00lbs / 34.02kg shells, 1920 Model
     Breech loading guns in casemate mounts
     on side, all amidships
      4 - 1.58" / 40.0 mm guns in single mounts, 2.00lbs / 0.91kg shells, 1920 Model
     Breech loading guns in deck mounts
     on centreline ends, evenly spread, all raised mounts - superfiring
   Weight of broadside 26,358 lbs / 11,956 kg
   Shells per gun, main battery: 120

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   11.0" / 279 mm   510.00 ft / 155.45 m   17.26 ft / 5.26 m
   Ends:   Unarmoured
     Main Belt covers 100 % of normal length

   - Torpedo Bulkhead and Bulges:
      1.50" / 38 mm   510.00 ft / 155.45 m   32.15 ft / 9.80 m

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   14.0" / 356 mm   4.00" / 102 mm      12.0" / 305 mm
   2nd:   1.50" / 38 mm         -         3.00" / 76 mm

   - Armour deck: 3.00" / 76 mm, Conning tower: 12.00" / 305 mm

Machinery:
   Oil fired boilers, steam turbines,
   Electric motors, 4 shafts, 54,554 shp / 40,697 Kw = 23.00 kts
   Range 12,000nm at 12.00 kts
   Bunker at max displacement = 4,574 tons

Complement:
   1,426 - 1,854

Cost:
   £9.503 million / $38.014 million

Distribution of weights at normal displacement:
   Armament: 2,996 tons, 7.4 %
   Armour: 12,099 tons, 29.9 %
      - Belts: 4,158 tons, 10.3 %
      - Torpedo bulkhead: 910 tons, 2.2 %
      - Armament: 3,499 tons, 8.6 %
      - Armour Deck: 3,228 tons, 8.0 %
      - Conning Tower: 305 tons, 0.8 %
   Machinery: 1,907 tons, 4.7 %
   Hull, fittings & equipment: 17,948 tons, 44.3 %
   Fuel, ammunition & stores: 5,125 tons, 12.7 %
   Miscellaneous weights: 400 tons, 1.0 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     54,991 lbs / 24,943 Kg = 24.5 x 16.5 " / 419 mm shells or 8.7 torpedoes
   Stability (Unstable if below 1.00): 1.21
   Metacentric height 7.7 ft / 2.3 m
   Roll period: 16.9 seconds
   Steadiness   - As gun platform (Average = 50 %): 48 %
         - Recoil effect (Restricted arc if above 1.00): 0.61
   Seaboat quality  (Average = 1.00): 1.18

Hull form characteristics:
   Hull has raised forecastle
   Block coefficient: 0.559
   Length to Beam Ratio: 7.06 : 1
   'Natural speed' for length: 28.06 kts
   Power going to wave formation at top speed: 38 %
   Trim (Max stability = 0, Max steadiness = 100): 40
   Bow angle (Positive = bow angles forward): 0.00 degrees
   Stern overhang: 0.00 ft / 0.00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      29.53 ft / 9.00 m
      - Forecastle (20 %):   22.97 ft / 7.00 m (19.69 ft / 6.00 m aft of break)
      - Mid (50 %):      19.69 ft / 6.00 m
      - Quarterdeck (15 %):   19.69 ft / 6.00 m
      - Stern:      19.69 ft / 6.00 m
      - Average freeboard:   20.87 ft / 6.36 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 90.5 %
      - Above water (accommodation/working, high = better): 152.9 %
   Waterplane Area: 58,161 Square feet or 5,403 Square metres
   Displacement factor (Displacement / loading): 100 %
   Structure weight / hull surface area: 225 lbs/sq ft or 1,098 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.99
      - Longitudinal: 1.12
      - Overall: 1.00
   Hull space for machinery, storage, compartmentation is adequate
   Room for accommodation and workspaces is excellent

Main belt armor sloped 20 degrees, giving a vertical height of 16.5 feet. Relative thickness to a 90 degree impact is 11.71 inches.

Misc Weight (400 tons):
250 tons fire control system
25 tons radar
25 tons long range wireless
25 tons night fighting gear
25 tons crane and catapult for floatplane
10 tons 2x floatplanes
40 tons reserve

[Delta Force]

18 Inch Twin Turret Study, CSA Battleship Turret Study laid down 1920

Displacement:
   35,350 t light; 37,691 t standard; 40,222 t normal; 42,246 t full load

Dimensions: Length overall / water x beam x draught
   787.40 ft / 787.40 ft x 104.99 ft (Bulges 111.55 ft) x 28.87 ft (normal load)
   240.00 m / 240.00 m x 32.00 m (Bulges 34.00 m)  x 8.80 m

Armament:
      8 - 18.00" / 457 mm guns (4x2 guns), 3,000.00lbs / 1,360.78kg shells, 1920 Model
     Breech loading guns in turrets (on barbettes)
     on centreline ends, evenly spread, 2 raised mounts - superfiring
      18 - 5.50" / 140 mm guns in single mounts, 75.00lbs / 34.02kg shells, 1920 Model
     Breech loading guns in casemate mounts
     on side, all amidships
      4 - 1.58" / 40.0 mm guns in single mounts, 2.00lbs / 0.91kg shells, 1920 Model
     Breech loading guns in deck mounts
     on centreline ends, evenly spread, all raised mounts - superfiring
   Weight of broadside 25,358 lbs / 11,502 kg
   Shells per gun, main battery: 108

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   11.0" / 279 mm   510.00 ft / 155.45 m   17.26 ft / 5.26 m
   Ends:   Unarmoured
     Main Belt covers 100 % of normal length

   - Torpedo Bulkhead and Bulges:
      1.50" / 38 mm   510.00 ft / 155.45 m   32.15 ft / 9.80 m

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   14.0" / 356 mm   4.00" / 102 mm      12.0" / 305 mm
   2nd:   1.50" / 38 mm         -         3.00" / 76 mm

   - Armour deck: 3.00" / 76 mm, Conning tower: 12.00" / 305 mm

Machinery:
   Oil fired boilers, steam turbines,
   Electric motors, 4 shafts, 54,285 shp / 40,497 Kw = 23.00 kts
   Range 12,000nm at 12.00 kts
   Bunker at max displacement = 4,555 tons

Complement:
   1,419 - 1,846

Cost:
   £9.716 million / $38.863 million

Distribution of weights at normal displacement:
   Armament: 3,104 tons, 7.7 %
   Armour: 11,762 tons, 29.2 %
      - Belts: 4,157 tons, 10.3 %
      - Torpedo bulkhead: 910 tons, 2.3 %
      - Armament: 3,175 tons, 7.9 %
      - Armour Deck: 3,217 tons, 8.0 %
      - Conning Tower: 303 tons, 0.8 %
   Machinery: 1,898 tons, 4.7 %
   Hull, fittings & equipment: 18,186 tons, 45.2 %
   Fuel, ammunition & stores: 4,872 tons, 12.1 %
   Miscellaneous weights: 400 tons, 1.0 %

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     53,127 lbs / 24,098 Kg = 18.2 x 18.0 " / 457 mm shells or 8.4 torpedoes
   Stability (Unstable if below 1.00): 1.20
   Metacentric height 7.6 ft / 2.3 m
   Roll period: 17.0 seconds
   Steadiness   - As gun platform (Average = 50 %): 48 %
         - Recoil effect (Restricted arc if above 1.00): 0.61
   Seaboat quality  (Average = 1.00): 1.16

Hull form characteristics:
   Hull has raised forecastle
   Block coefficient: 0.555
   Length to Beam Ratio: 7.06 : 1
   'Natural speed' for length: 28.06 kts
   Power going to wave formation at top speed: 38 %
   Trim (Max stability = 0, Max steadiness = 100): 40
   Bow angle (Positive = bow angles forward): 0.00 degrees
   Stern overhang: 0.00 ft / 0.00 m
   Freeboard (% = measuring location as a percentage of overall length):
      - Stem:      29.53 ft / 9.00 m
      - Forecastle (20 %):   22.97 ft / 7.00 m (19.69 ft / 6.00 m aft of break)
      - Mid (50 %):      19.69 ft / 6.00 m
      - Quarterdeck (15 %):   19.69 ft / 6.00 m
      - Stern:      19.69 ft / 6.00 m
      - Average freeboard:   20.87 ft / 6.36 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 92.5 %
      - Above water (accommodation/working, high = better): 153.2 %
   Waterplane Area: 57,971 Square feet or 5,386 Square metres
   Displacement factor (Displacement / loading): 99 %
   Structure weight / hull surface area: 229 lbs/sq ft or 1,116 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.98
      - Longitudinal: 1.13
      - Overall: 1.00
   Hull space for machinery, storage, compartmentation is adequate
   Room for accommodation and workspaces is excellent

Main belt armor sloped 20 degrees, giving a vertical height of 16.5 feet. Relative thickness to a 90 degree impact is 11.71 inches.

Misc Weight (400 tons):
250 tons fire control system
25 tons radar
25 tons long range wireless
25 tons night fighting gear
25 tons crane and catapult for floatplane
10 tons 2x floatplanes
40 tons reserve

[Borys]

Ahoj!
I drool looking at those thin belts ....
Borys

[Sachmle]

Ahoj!
I drool looking at those thin belts ....
Borys

And I get a migraine trying to figure out how to fit 9 13.5" twin turrets and superstructure, and deck level casemates, on 240m.

[snip]

And I get a migraine trying to figure out how to fit 9 13.5" twin turrets and superstructure, and deck level casemates, on 240m.

Simple answer: you cant.

[Darman]

And I get a migraine trying to figure out how to fit 9 13.5" twin turrets and superstructure, and deck level casemates, on 240m.

Very very glad I wasn't the only one.  i spent about 5 minutes trying to wrap my head around that and then i realized he had done more ships...

[TexanCowboy]

And all 9 are on the centerline....I mean, unless he went to Japanese style carrier funnels and a really, really small island...and it probably still wouldn't fit.

[Kaiser Kirk]

And I get a migraine trying to figure out how to fit 9 13.5" twin turrets and superstructure, and deck level casemates, on 240m.

Simple answer: you cant.

Doesn't seem that impossible to me.

Agincourt was 7 x Twin 12" on 192m.   
Going from 12" to 13.5" will mean Barbette radius will increase slightly by just a couple feet.  Barrel length will increase, adding ~6.25ft to each gun. However, when one gun is superimposed, the extra length means less.

All and all, this vessel needs to fit in two more twins on an additional 48m / 157 ft. midsection. 

I would think two turrets would fit in that space. - especially if you go with making compact little pyramids like her aft guns.   Imagine one three turret pyramid "aft", one "amidships" and one "fore".  Ta Da - 18 guns.

[Sachmle]

She's ~787' long with 15% quarterdeck and 20% forecastle. That's 118' and 157' respectively that is unavailable for weapons mounts. That leaves 512' for all weapons and superstructure. Using a line drawing of Conqueror to get the sizing of the RN 13.5"/45 Mark V(L) gun in the Mark II turret you get ~180' per group of three. That's 540' total, but there is only 512' available. So, 9 won't fit, IMHO. 7 is pushing it. Granted this is using Nelrod layouts for the groupings.

Included a drawing. Total space is 512' guns are 67' each. 1pix=1' scale. Notice the lack of room for anything else, not to mention that they can't even all fit together.

[Delta Force]

Well, compared to Agincourt, each barrel is 5.625 feet longer, and the barrel length itself adds 50.625 feet to a ship that is 115.9 feet longer.

As for the casemates, I didn't know you could put them on deck, so I'll have to fix that. I've never seen casemates on deck in any photos.

[Sachmle]

Well, compared to Agincourt, each barrel is 5.625 feet longer, and the barrel length itself adds 50.625 feet to a ship that is 115.9 feet longer.

As for the casemates, I didn't know you could put them on deck, so I'll have to fix that. I've never seen casemates on deck in any photos.

If you don't set them as below deck in SS2 they're considered to be on main deck level. As for a photo of a ship w/ deck level casemates, check this photo of Derfflinger

[TexanCowboy]

Doesn't seem that impossible to me.

Agincourt was 7 x Twin 12" on 192m.   
[/quote]

Yes, but Agincourt had two side turrets. These are all centerline, so...where do the funnells go?

[Kaiser Kirk]

What side turrets?
My book doesn't show any, nor does the image on Wiki.

http://en.wikipedia.org/wiki/File:HMS_Agincourt_Skizze.jpg

Sachmle's work is interesting, but looking at Agincourt, or say Arkansas, I don't think 35% of the ship was off limits.
http://www.blueprintbox.com/watermark-gif.php?img=./data/media/24/bb-33-uss-arkansas-1934.gif
Plus, even if you stuck to those limits -if the edge of barbette comes to that spot, then the barrels can project fore and aft into that space, which recovers another 20m or so.

On the casement deck mounts- I've always been bedeviled by the fact that if I then extend the upperbelt to actually armor the darn things, I get a warning about belt to tall for hull.