Aztec Ship Designs 1913

[TacCovert4]

While the current built program is maxxing out capacity for the Sultanate, design studies have been started for the next generation of Aztec Battleship.  The first concept, a rugged ship designed for Caribbean Operations.

BB-X, Aztec Battleship laid down 1916

Displacement:
   28,535 t light; 30,277 t standard; 31,948 t normal; 33,286 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (584.46 ft / 574.15 ft) x 91.86 ft x (29.53 / 30.62 ft)
   (178.14 m / 175.00 m) x 28.00 m  x (9.00 / 9.33 m)

Armament:
      12 - 14.17" / 360 mm 45.0 cal guns - 1,435.69lbs / 651.22kg shells, 110 per gun
     Breech loading guns in turret on barbette mounts, 1916 Model
     4 x 3-gun mounts on centreline ends, evenly spread
      2 raised mounts - superfiring
      14 - 3.94" / 100 mm 50.0 cal guns - 32.30lbs / 14.65kg shells, 200 per gun
     Quick firing guns in deck and hoist mounts, 1913 Model
     14 x Single mounts on sides, evenly spread
      16 - 0.31" / 8.0 mm 70.0 cal guns - 0.02lbs / 0.01kg shells, 1,500 per gun
     Machine guns in deck mounts, 1916 Model
     8 x Twin mounts on centreline, evenly spread
      8 double raised mounts
      Weight of broadside 17,681 lbs / 8,020 kg

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   15.7" / 400 mm   426.51 ft / 130.00 m   13.12 ft / 4.00 m
   Ends:   Unarmoured
     Main Belt covers 114 % of normal length

   - Torpedo Bulkhead - Additional damage containing bulkheads:
      1.57" / 40 mm   393.70 ft / 120.00 m   26.25 ft / 8.00 m
   Beam between torpedo bulkheads 65.62 ft / 20.00 m

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   16.5" / 420 mm   6.69" / 170 mm      15.7" / 400 mm
   2nd:   2.95" / 75 mm   1.38" / 35 mm      2.95" / 75 mm

   - Armoured deck - multiple decks:
   For and Aft decks: 4.53" / 115 mm
   Forecastle: 0.00" / 0 mm  Quarter deck: 3.35" / 85 mm

   - Conning towers: Forward 16.54" / 420 mm, Aft 0.00" / 0 mm

Machinery:
   Oil fired boilers, steam turbines,
   Electric motors, 4 shafts, 38,018 shp / 28,361 Kw = 21.00 kts
   Range 8,000nm at 12.00 kts
   Bunker at max displacement = 3,009 tons

Complement:
   1,194 - 1,553

Cost:
   £4.668 million / $18.672 million

Distribution of weights at normal displacement:
   Armament: 3,707 tons, 11.6 %
      - Guns: 3,707 tons, 11.6 %
   Armour: 12,153 tons, 38.0 %
      - Belts: 3,807 tons, 11.9 %
      - Torpedo bulkhead: 602 tons, 1.9 %
      - Armament: 4,085 tons, 12.8 %
      - Armour Deck: 3,301 tons, 10.3 %
      - Conning Tower: 359 tons, 1.1 %
   Machinery: 1,416 tons, 4.4 %
   Hull, fittings & equipment: 10,422 tons, 32.6 %
   Fuel, ammunition & stores: 3,414 tons, 10.7 %
   Miscellaneous weights: 836 tons, 2.6 %
      - Hull below water: 336 tons
      - Above deck: 500 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     44,752 lbs / 20,299 Kg = 31.4 x 14.2 " / 360 mm shells or 7.1 torpedoes
   Stability (Unstable if below 1.00): 1.00
   Metacentric height 4.4 ft / 1.3 m
   Roll period: 18.4 seconds
   Steadiness   - As gun platform (Average = 50 %): 70 %
         - Recoil effect (Restricted arc if above 1.00): 1.28
   Seaboat quality  (Average = 1.00): 1.40

Hull form characteristics:
   Hull has a flush deck,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.718 / 0.721
   Length to Beam Ratio: 6.25 : 1
   'Natural speed' for length: 23.96 kts
   Power going to wave formation at top speed: 47 %
   Trim (Max stability = 0, Max steadiness = 100): 50
   Bow angle (Positive = bow angles forward): 15.00 degrees
   Stern overhang: 3.28 ft / 1.00 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
      - Forecastle:   15.40 %,  26.25 ft / 8.00 m,  23.79 ft / 7.25 m
      - Forward deck:   30.00 %,  23.79 ft / 7.25 m,  19.69 ft / 6.00 m
      - Aft deck:   39.20 %,  19.69 ft / 6.00 m,  19.69 ft / 6.00 m
      - Quarter deck:   15.40 %,  19.69 ft / 6.00 m,  19.69 ft / 6.00 m
      - Average freeboard:      21.08 ft / 6.43 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 88.3 %
      - Above water (accommodation/working, high = better): 141.0 %
   Waterplane Area: 42,955 Square feet or 3,991 Square metres
   Displacement factor (Displacement / loading): 101 %
   Structure weight / hull surface area: 203 lbs/sq ft or 993 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.95
      - Longitudinal: 1.72
      - Overall: 1.00
   Adequate machinery, storage, compartmentation space
   Excellent accommodation and workspace room
   Ship has slow, easy roll, a good, steady gun platform
   Good seaboat, rides out heavy weather easily

336t - Electric Drives
300t - 1910 FC
200t - Flag Facilities

Decks: 
Main - 100mm w/15mm Splinter
Quarter - 70mm w/15mm Splinter

[snip]

Something I remember coming up with another big armored behemoth (IIRC the Maori CrossMirage from N3) such as this was that about as thick as you could go with armor in this period for big plates of belt and deck sections is about 350mm without running into massive quality control problems (these are not as great a concern with something smaller such as a turret face). So while I dont think the 400mm belt is impossible, it boarders on impractical IME presuming my recollection of the topic is accurate.

That said, its a tough nut to crack and makes me glad I have 410mm guns in the pipe now. More comments when its not super late at night.

[Kaiser Kirk]

Something I remember coming up with another big armored behemoth (IIRC the Maori CrossMirage from N3) such as this was that about as thick as you could go with armor in this period for big plates of belt and deck sections is about 350mm without running into massive quality control problems (these are not as great a concern with something smaller such as a turret face). So while I dont think the 400mm belt is impossible, it boarders on impractical IME presuming my recollection of the topic is accurate.

That said, its a tough nut to crack and makes me glad I have 410mm guns in the pipe now. More comments when its not super late at night.

That's something that came up on Wesworld as well.
It's not really discussed in detail in N7 that I know of and basically is a realism consideration.

From what I recall, the quality control issue leads to more rejects. Plus, the thickness in excess of 350mm is less effective than expected.
So 350mm = 350mm.  360mm =  358mm?  type thing.  Still, you see various ships with more because sometimes that's the only real option.
I don't know if naval armor caused the 'shatter gap' effect, probably not as naval shells were slower than HV tank rounds.
For my part I'm not going to do that math for any combats... the belt+ (any protected deck/2) is enough extra figuring :)

As a realsim matter it's a good reason to transition to interior belts and exterior decapping plates, which is a later tech. Ironically while the Italians specified the exterior plate for use as a decapper, the Americans kinda got there by accident, seeking to prevent outboard flotation loss with modest armoring of the outer shell.

[TacCovert4]

Something I remember coming up with another big armored behemoth (IIRC the Maori CrossMirage from N3) such as this was that about as thick as you could go with armor in this period for big plates of belt and deck sections is about 350mm without running into massive quality control problems (these are not as great a concern with something smaller such as a turret face). So while I dont think the 400mm belt is impossible, it boarders on impractical IME presuming my recollection of the topic is accurate.

That said, its a tough nut to crack and makes me glad I have 410mm guns in the pipe now. More comments when its not super late at night.

That's something that came up on Wesworld as well.
It's not really discussed in detail in N7 that I know of and basically is a realism consideration.

From what I recall, the quality control issue leads to more rejects. Plus, the thickness in excess of 350mm is less effective than expected.
So 350mm = 350mm.  360mm =  358mm?  type thing.  Still, you see various ships with more because sometimes that's the only real option.
I don't know if naval armor caused the 'shatter gap' effect, probably not as naval shells were slower than HV tank rounds.
For my part I'm not going to do that math for any combats... the belt+ (any protected deck/2) is enough extra figuring :)

As a realsim matter it's a good reason to transition to interior belts and exterior decapping plates, which is a later tech. Ironically while the Italians specified the exterior plate for use as a decapper, the Americans kinda got there by accident, seeking to prevent outboard flotation loss with modest armoring of the outer shell.

Well, this one is a design study. And maybe a 50mm splinter bulkhead behind a 350mm belt?

[Kaiser Kirk]

Well, this one is a design study. And maybe a 50mm splinter bulkhead behind a 350mm belt?

On the one hand a similar armor arrangement was tried on the Gangut class.
but I have a feeling that multi-layer armor systems fall afoul of the intent with placing the interior belts as a higher tech..

The period approach would be to have "protective deck -multiple decks" which best describes the Pennsylvania class this seems to Echo.
Then you define the lowest protective deck as behind the belt and Xmm thick.
With 88% hull space, you're well within the margins.

The 100mm guns are really a little light. For a 1916 ship you're looking at FC out to 12km, and wanting to seriously damage a 1000ton DD, or a cruiser. 100mm won't be very effective.

[TacCovert4]

Redesigned.  Trying for the epitome of 'slow and tough'.

BB-X, Aztec Battleship laid down 1916

Displacement:
   28,018 t light; 29,834 t standard; 31,098 t normal; 32,109 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (565.07 ft / 557.74 ft) x 91.86 ft x (30.35 / 31.21 ft)
   (172.23 m / 170.00 m) x 28.00 m  x (9.25 / 9.51 m)

Armament:
      12 - 14.17" / 360 mm 45.0 cal guns - 1,435.70lbs / 651.22kg shells, 120 per gun
     Breech loading guns in turret on barbette mounts, 1916 Model
     4 x 3-gun mounts on centreline ends, evenly spread
      2 raised mounts - superfiring
      16 - 3.94" / 100 mm 50.0 cal guns - 32.30lbs / 14.65kg shells, 160 per gun
     Quick firing guns in deck and hoist mounts, 1913 Model
     16 x Single mounts on sides, evenly spread
      Weight of broadside 17,745 lbs / 8,049 kg

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   13.8" / 350 mm   459.32 ft / 140.00 m   13.12 ft / 4.00 m
   Ends:   Unarmoured
     Main Belt covers 127 % of normal length

   - Torpedo Bulkhead - Additional damage containing bulkheads:
      1.97" / 50 mm   426.51 ft / 130.00 m   22.97 ft / 7.00 m
   Beam between torpedo bulkheads 52.49 ft / 16.00 m

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   13.8" / 350 mm   6.30" / 160 mm      13.8" / 350 mm
   2nd:   2.95" / 75 mm   1.97" / 50 mm      2.95" / 75 mm

   - Protected deck - multiple decks:
   For and Aft decks: 6.30" / 160 mm
   Forecastle: 2.36" / 60 mm  Quarter deck: 2.36" / 60 mm

   - Conning towers: Forward 13.78" / 350 mm, Aft 0.00" / 0 mm

Machinery:
   Oil fired boilers, steam turbines,
   Electric motors, 4 shafts, 45,034 shp / 33,595 Kw = 22.00 kts
   Range 6,000nm at 12.00 kts
   Bunker at max displacement = 2,275 tons

Complement:
   1,170 - 1,522

Cost:
   £4.709 million / $18.836 million

Distribution of weights at normal displacement:
   Armament: 3,726 tons, 12.0 %
      - Guns: 3,726 tons, 12.0 %
   Armour: 12,091 tons, 38.9 %
      - Belts: 3,509 tons, 11.3 %
      - Torpedo bulkhead: 713 tons, 2.3 %
      - Armament: 3,322 tons, 10.7 %
      - Armour Deck: 4,253 tons, 13.7 %
      - Conning Tower: 294 tons, 0.9 %
   Machinery: 1,678 tons, 5.4 %
   Hull, fittings & equipment: 9,608 tons, 30.9 %
   Fuel, ammunition & stores: 3,080 tons, 9.9 %
   Miscellaneous weights: 916 tons, 2.9 %
      - Hull below water: 440 tons
      - Above deck: 476 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     37,900 lbs / 17,191 Kg = 26.6 x 14.2 " / 360 mm shells or 6.2 torpedoes
   Stability (Unstable if below 1.00): 1.03
   Metacentric height 4.7 ft / 1.4 m
   Roll period: 17.9 seconds
   Steadiness   - As gun platform (Average = 50 %): 51 %
         - Recoil effect (Restricted arc if above 1.00): 0.94
   Seaboat quality  (Average = 1.00): 1.02

Hull form characteristics:
   Hull has a flush deck,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.700 / 0.703
   Length to Beam Ratio: 6.07 : 1
   'Natural speed' for length: 23.62 kts
   Power going to wave formation at top speed: 51 %
   Trim (Max stability = 0, Max steadiness = 100): 50
   Bow angle (Positive = bow angles forward): 10.00 degrees
   Stern overhang: 3.28 ft / 1.00 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
      - Forecastle:   20.00 %,  22.97 ft / 7.00 m,  19.69 ft / 6.00 m
      - Forward deck:   30.00 %,  19.69 ft / 6.00 m,  16.40 ft / 5.00 m
      - Aft deck:   35.00 %,  16.40 ft / 5.00 m,  16.40 ft / 5.00 m
      - Quarter deck:   15.00 %,  16.40 ft / 5.00 m,  16.40 ft / 5.00 m
      - Average freeboard:      17.81 ft / 5.43 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 119.5 %
      - Above water (accommodation/working, high = better): 114.7 %
   Waterplane Area: 41,067 Square feet or 3,815 Square metres
   Displacement factor (Displacement / loading): 97 %
   Structure weight / hull surface area: 203 lbs/sq ft or 989 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.95
      - Longitudinal: 1.45
      - Overall: 1.00
   Cramped machinery, storage, compartmentation space
   Adequate accommodation and workspace room

420t - Electric Drives
20t - Additional DC Pumps

100t - Flag Facilities
376t - 1910 FC

Forecastle and Quarterdeck - Single 60mm Deck slopes and flat.

F/A Deck:
Main - 100mm flat, 150mm slopes (slopes behind above-water portion of belt)
Splinter - 25mm flat, 40mm slopes (slopes meet bottom of belt)

[TacCovert4]

As for the secbat being 'light'....that's unfortunately a function of my available guns.  I can either go with a 15cm gun or a 10cm gun.  The former is a bit slow for taking on destroyers and torpedo boats, a major threat in the Caribbean.  The latter too light for taking on cruisers, though 36cm HE could be used for cruisers.  So given the theater of operations, and the fact that shell splashes of 10 and 15 centimeter guns are just too alike to use a mixed battery effectively, 10cm is the better solution for now, though hopefully a 12 or 13 centimeter gun would be ready by any mid-life refit.

[snip]

I think your TDS is too deep, your unnecessarily cramping the rest of the internals. Make your beam between bulkheads something in the 22m range (look for when it starts getting the Machinery, Storage, Compartmentalization space below 100% at least) and use the saved length from that on the main belt to make it taller. That might also help with getting you a larger sability cushion than .03 befor there might be trouble.

[TacCovert4]

I think your TDS is too deep, your unnecessarily cramping the rest of the internals. Make your beam between bulkheads something in the 22m range (look for when it starts getting the Machinery, Storage, Compartmentalization space below 100% at least) and use the saved length from that on the main belt to make it taller. That might also help with getting you a larger sability cushion than .03 befor there might be trouble.

Bumping it to 22m beam, I can shorten my belt to 110m with plenty of room to spare on the essential spaces. And take my belt height to 5m, so 2 full decks high.......still does nothing for stability.  Something about these short-fat-slow BBs, stability is just a nightmare to work out.

[Jefgte]

IMO, you could have better BB with some adjustments...
Sorry, no vexation
;)

Displacement:
   28,018 t light; 29,834 t standard; 31,098 t normal; 32,109 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (565.07 ft / 557.74 ft) x 91.86 ft x (30.35 / 31.21 ft)
   (172.23 m / 170.00 m) x 28.00 m  x (9.25 / 9.51 m)

Armament:
      12 - 14.17" / 360 mm 45.0 cal guns - 1,435.70lbs / 651.22kg shells, 120 per gun
     Breech loading guns in turret on barbette mounts, 1916 Model
     4 x 3-gun mounts on centreline ends, evenly spread
      2 raised mounts - superfiring
      16 - 3.94" / 100 mm 50.0 cal guns - 32.30lbs / 14.65kg shells, 160 per gun
     Quick firing guns in deck and hoist mounts, 1913 Model
     16 x Single mounts on sides, evenly spread
      Weight of broadside 17,745 lbs / 8,049 kg
Use 150/45 (1905) of the Saladin class for secondary
Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   13.8" / 350 mm   459.32 ft / 140.00 m   13.12 ft / 4.00 m
   Ends:   Unarmoured
     Main Belt covers 127 % of normal length => 127% is too much
Add Ends:   4.72" / 120 mm   ft /  m    ft /  m
Add Upper:   4.72" / 120 mm   ft /  m    ft /  m
   - Torpedo Bulkhead - Additional damage containing bulkheads:
      1.97" / 50 mm   426.51 ft / 130.00 m   22.97 ft / 7.00 m => 28.35ft
   Beam between torpedo bulkheads 52.49 ft / 16.00 m => 22.00m

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   13.8" / 350 mm   6.30" / 160 mm      13.8" / 350 mm
   2nd:   2.95" / 75 mm   1.97" / 50 mm      2.95" / 75 mm

   - Protected deck - multiple decks:
   For and Aft decks: 6.30" / 160 mm => 100 to 120 There is no naval bombers in 1916
   Forecastle: 2.36" / 60 mm  Quarter deck: 2.36" / 60 mm

   - Conning towers: Forward 13.78" / 350 mm, Aft 0.00" / 0 mm => 150 to 200

Machinery:
   Oil fired boilers, steam turbines,
   Electric motors, 4 shafts, 45,034 shp / 33,595 Kw = 22.00 kts
   Range 6,000nm at 12.00 kts
   Bunker at max displacement = 2,275 tons

Complement:
   1,170 - 1,522

Cost:
   £4.709 million / $18.836 million

Distribution of weights at normal displacement:
   Armament: 3,726 tons, 12.0 %
      - Guns: 3,726 tons, 12.0 %
   Armour: 12,091 tons, 38.9 %
      - Belts: 3,509 tons, 11.3 %
      - Torpedo bulkhead: 713 tons, 2.3 %
      - Armament: 3,322 tons, 10.7 %
      - Armour Deck: 4,253 tons, 13.7 %
      - Conning Tower: 294 tons, 0.9 %
   Machinery: 1,678 tons, 5.4 %
   Hull, fittings & equipment: 9,608 tons, 30.9 %
   Fuel, ammunition & stores: 3,080 tons, 9.9 %
   Miscellaneous weights: 916 tons, 2.9 %
      - Hull below water: 440 tons
      - Above deck: 476 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     37,900 lbs / 17,191 Kg = 26.6 x 14.2 " / 360 mm shells or 6.2 torpedoes
Survivability is not top, you could have certainly 20,000 Kg
   Stability (Unstable if below 1.00): 1.03 => not enough
   Metacentric height 4.7 ft / 1.4 m
   Roll period: 17.9 seconds
   Steadiness   - As gun platform (Average = 50 %): 51 %
         - Recoil effect (Restricted arc if above 1.00): 0.94 => too high, your hull is mechanical stressed
   Seaboat quality  (Average = 1.00): 1.02

Hull form characteristics:
   Hull has a flush deck,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.700 / 0.703 => too high
   Length to Beam Ratio: 6.07 : 1
   'Natural speed' for length: 23.62 kts
   Power going to wave formation at top speed: 51 %
   Trim (Max stability = 0, Max steadiness = 100): 50
   Bow angle (Positive = bow angles forward): 10.00 degrees
   Stern overhang: 3.28 ft / 1.00 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
      - Forecastle:   20.00 %,  22.97 ft / 7.00 m,  19.69 ft / 6.00 m
      - Forward deck:   30.00 %,  19.69 ft / 6.00 m,  16.40 ft / 5.00 m
      - Aft deck:   35.00 %,  16.40 ft / 5.00 m,  16.40 ft / 5.00 m
      - Quarter deck:   15.00 %,  16.40 ft / 5.00 m,  16.40 ft / 5.00 m
      - Average freeboard:      17.81 ft / 5.43 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 119.5 %
      - Above water (accommodation/working, high = better): 114.7 %
   Waterplane Area: 41,067 Square feet or 3,815 Square metres
   Displacement factor (Displacement / loading): 97 %
   Structure weight / hull surface area: 203 lbs/sq ft or 989 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.95
      - Longitudinal: 1.45
      - Overall: 1.00
   Cramped machinery, storage, compartmentation space
   Adequate accommodation and workspace room
  => you could certainly have:
Ship has slow, easy roll, a good, steady gun platform
   Excellent seaboat, comfortable, can fire her guns in the heaviest weather

[TacCovert4]

IMO, you could have better BB with some adjustments...
Sorry, no vexation
;)

Displacement:
   28,018 t light; 29,834 t standard; 31,098 t normal; 32,109 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (565.07 ft / 557.74 ft) x 91.86 ft x (30.35 / 31.21 ft)
   (172.23 m / 170.00 m) x 28.00 m  x (9.25 / 9.51 m)

Armament:
      12 - 14.17" / 360 mm 45.0 cal guns - 1,435.70lbs / 651.22kg shells, 120 per gun
     Breech loading guns in turret on barbette mounts, 1916 Model
     4 x 3-gun mounts on centreline ends, evenly spread
      2 raised mounts - superfiring
      16 - 3.94" / 100 mm 50.0 cal guns - 32.30lbs / 14.65kg shells, 160 per gun
     Quick firing guns in deck and hoist mounts, 1913 Model
     16 x Single mounts on sides, evenly spread
      Weight of broadside 17,745 lbs / 8,049 kg
Use 150/45 (1905) of the Saladin class for secondary
Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   13.8" / 350 mm   459.32 ft / 140.00 m   13.12 ft / 4.00 m
   Ends:   Unarmoured
     Main Belt covers 127 % of normal length => 127% is too much
Add Ends:   4.72" / 120 mm   ft /  m    ft /  m
Add Upper:   4.72" / 120 mm   ft /  m    ft /  m
   - Torpedo Bulkhead - Additional damage containing bulkheads:
      1.97" / 50 mm   426.51 ft / 130.00 m   22.97 ft / 7.00 m => 28.35ft
   Beam between torpedo bulkheads 52.49 ft / 16.00 m => 22.00m

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   13.8" / 350 mm   6.30" / 160 mm      13.8" / 350 mm
   2nd:   2.95" / 75 mm   1.97" / 50 mm      2.95" / 75 mm

   - Protected deck - multiple decks:
   For and Aft decks: 6.30" / 160 mm => 100 to 120 There is no naval bombers in 1916
   Forecastle: 2.36" / 60 mm  Quarter deck: 2.36" / 60 mm

   - Conning towers: Forward 13.78" / 350 mm, Aft 0.00" / 0 mm => 150 to 200

Machinery:
   Oil fired boilers, steam turbines,
   Electric motors, 4 shafts, 45,034 shp / 33,595 Kw = 22.00 kts
   Range 6,000nm at 12.00 kts
   Bunker at max displacement = 2,275 tons

Complement:
   1,170 - 1,522

Cost:
   £4.709 million / $18.836 million

Distribution of weights at normal displacement:
   Armament: 3,726 tons, 12.0 %
      - Guns: 3,726 tons, 12.0 %
   Armour: 12,091 tons, 38.9 %
      - Belts: 3,509 tons, 11.3 %
      - Torpedo bulkhead: 713 tons, 2.3 %
      - Armament: 3,322 tons, 10.7 %
      - Armour Deck: 4,253 tons, 13.7 %
      - Conning Tower: 294 tons, 0.9 %
   Machinery: 1,678 tons, 5.4 %
   Hull, fittings & equipment: 9,608 tons, 30.9 %
   Fuel, ammunition & stores: 3,080 tons, 9.9 %
   Miscellaneous weights: 916 tons, 2.9 %
      - Hull below water: 440 tons
      - Above deck: 476 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     37,900 lbs / 17,191 Kg = 26.6 x 14.2 " / 360 mm shells or 6.2 torpedoes
Survivability is not top, you could have certainly 20,000 Kg
   Stability (Unstable if below 1.00): 1.03 => not enough
   Metacentric height 4.7 ft / 1.4 m
   Roll period: 17.9 seconds
   Steadiness   - As gun platform (Average = 50 %): 51 %
         - Recoil effect (Restricted arc if above 1.00): 0.94 => too high, your hull is mechanical stressed
   Seaboat quality  (Average = 1.00): 1.02

Hull form characteristics:
   Hull has a flush deck,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.700 / 0.703 => too high
   Length to Beam Ratio: 6.07 : 1
   'Natural speed' for length: 23.62 kts
   Power going to wave formation at top speed: 51 %
   Trim (Max stability = 0, Max steadiness = 100): 50
   Bow angle (Positive = bow angles forward): 10.00 degrees
   Stern overhang: 3.28 ft / 1.00 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
      - Forecastle:   20.00 %,  22.97 ft / 7.00 m,  19.69 ft / 6.00 m
      - Forward deck:   30.00 %,  19.69 ft / 6.00 m,  16.40 ft / 5.00 m
      - Aft deck:   35.00 %,  16.40 ft / 5.00 m,  16.40 ft / 5.00 m
      - Quarter deck:   15.00 %,  16.40 ft / 5.00 m,  16.40 ft / 5.00 m
      - Average freeboard:      17.81 ft / 5.43 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 119.5 %
      - Above water (accommodation/working, high = better): 114.7 %
   Waterplane Area: 41,067 Square feet or 3,815 Square metres
   Displacement factor (Displacement / loading): 97 %
   Structure weight / hull surface area: 203 lbs/sq ft or 989 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.95
      - Longitudinal: 1.45
      - Overall: 1.00
   Cramped machinery, storage, compartmentation space
   Adequate accommodation and workspace room
  => you could certainly have:
Ship has slow, easy roll, a good, steady gun platform
   Excellent seaboat, comfortable, can fire her guns in the heaviest weather

On the matter of the stability, and mechanical stresses, I think that's just going to come down to sheer mass at play.  Every time I fiddle with this design, it just doesn't change anything notable without screwing up something else pretty badly.  I think I'm just going to have to bite the bullet and either pull a whole turret off, or raise the tonnage to 30,000t-31,000t.  The 27-28kt range is just too light to get 12 x 36cm guns, plus a secondary of any worth, plus heavy armor.....and have a ship that is stable and not mechanically stressed.

[TacCovert4]

As you can see......far better seakeeping and finer lines, and even better armor distribution (depending on opinion).  But stability is still marginal and mechanical stress is still pretty garbage.  I think that ultimately I'm just going to have to bite the bullet and accept that I can't get an adequate battleship, even a slow one, on less than 30,000t.  I'm going to have to make major sacrifices somewhere.


BB-X, Aztec Battleship laid down 1916

Displacement:
   27,613 t light; 29,419 t standard; 30,575 t normal; 31,500 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (587.46 ft / 580.71 ft) x 91.86 ft x (30.35 / 31.13 ft)
   (179.06 m / 177.00 m) x 28.00 m  x (9.25 / 9.49 m)

Armament:
      12 - 14.17" / 360 mm 45.0 cal guns - 1,435.69lbs / 651.22kg shells, 120 per gun
     Breech loading guns in turret on barbette mounts, 1916 Model
     4 x 3-gun mounts on centreline ends, evenly spread
      2 raised mounts - superfiring
      16 - 3.94" / 100 mm 50.0 cal guns - 32.30lbs / 14.65kg shells, 160 per gun
     Quick firing guns in deck and hoist mounts, 1913 Model
     16 x Single mounts on sides, evenly spread
      Weight of broadside 17,745 lbs / 8,049 kg

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   13.8" / 350 mm   459.32 ft / 140.00 m   13.12 ft / 4.00 m
   Ends:   4.72" / 120 mm     98.43 ft / 30.00 m   13.12 ft / 4.00 m
     22.97 ft / 7.00 m Unarmoured ends
     Main Belt covers 122 % of normal length

   - Torpedo Bulkhead - Additional damage containing bulkheads:
      1.97" / 50 mm   426.51 ft / 130.00 m   29.53 ft / 9.00 m
   Beam between torpedo bulkheads 72.18 ft / 22.00 m

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   13.8" / 350 mm   6.30" / 160 mm      13.8" / 350 mm
   2nd:   2.95" / 75 mm   1.97" / 50 mm      2.95" / 75 mm

   - Protected deck - multiple decks:
   For and Aft decks: 4.72" / 120 mm
   Forecastle: 2.36" / 60 mm  Quarter deck: 2.36" / 60 mm

   - Conning towers: Forward 11.81" / 300 mm, Aft 0.00" / 0 mm

Machinery:
   Oil fired boilers, steam turbines,
   Electric motors, 4 shafts, 43,179 shp / 32,212 Kw = 22.00 kts
   Range 5,500nm at 12.00 kts
   Bunker at max displacement = 2,081 tons

Complement:
   1,155 - 1,502

Cost:
   £4.670 million / $18.680 million

Distribution of weights at normal displacement:
   Armament: 3,726 tons, 12.2 %
      - Guns: 3,726 tons, 12.2 %
   Armour: 11,513 tons, 37.7 %
      - Belts: 3,730 tons, 12.2 %
      - Torpedo bulkhead: 917 tons, 3.0 %
      - Armament: 3,322 tons, 10.9 %
      - Armour Deck: 3,295 tons, 10.8 %
      - Conning Tower: 249 tons, 0.8 %
   Machinery: 1,609 tons, 5.3 %
   Hull, fittings & equipment: 9,849 tons, 32.2 %
   Fuel, ammunition & stores: 2,962 tons, 9.7 %
   Miscellaneous weights: 916 tons, 3.0 %
      - Hull below water: 440 tons
      - Above deck: 476 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     37,339 lbs / 16,937 Kg = 26.2 x 14.2 " / 360 mm shells or 6.4 torpedoes
   Stability (Unstable if below 1.00): 1.02
   Metacentric height 4.6 ft / 1.4 m
   Roll period: 18.1 seconds
   Steadiness   - As gun platform (Average = 50 %): 56 %
         - Recoil effect (Restricted arc if above 1.00): 0.99
   Seaboat quality  (Average = 1.00): 1.12

Hull form characteristics:
   Hull has a flush deck,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.661 / 0.664
   Length to Beam Ratio: 6.32 : 1
   'Natural speed' for length: 24.10 kts
   Power going to wave formation at top speed: 48 %
   Trim (Max stability = 0, Max steadiness = 100): 50
   Bow angle (Positive = bow angles forward): 10.00 degrees
   Stern overhang: 3.28 ft / 1.00 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
      - Forecastle:   20.00 %,  19.69 ft / 6.00 m,  19.69 ft / 6.00 m
      - Forward deck:   30.00 %,  19.69 ft / 6.00 m,  16.40 ft / 5.00 m
      - Aft deck:   35.00 %,  16.40 ft / 5.00 m,  16.40 ft / 5.00 m
      - Quarter deck:   15.00 %,  16.40 ft / 5.00 m,  16.40 ft / 5.00 m
      - Average freeboard:      17.55 ft / 5.35 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 87.4 %
      - Above water (accommodation/working, high = better): 116.8 %
   Waterplane Area: 41,279 Square feet or 3,835 Square metres
   Displacement factor (Displacement / loading): 97 %
   Structure weight / hull surface area: 205 lbs/sq ft or 999 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.96
      - Longitudinal: 1.50
      - Overall: 1.00
   Adequate machinery, storage, compartmentation space
   Adequate accommodation and workspace room

420t - Electric Drives
20t - Additional DC Pumps

100t - Flag Facilities
376t - 1910 FC

Forecastle and Quarterdeck - Single 60mm Deck slopes and flat.

F/A Deck:
Main - 80mm flat, 120mm slopes (slopes behind above-water portion of belt)
Splinter - 20mm

[Kaiser Kirk]

As you can see......far better seakeeping and finer lines, and even better armor distribution (depending on opinion).  But stability is still marginal and mechanical stress is still pretty garbage.  I think that ultimately I'm just going to have to bite the bullet and accept that I can't get an adequate battleship, even a slow one, on less than 30,000t.  I'm going to have to make major sacrifices somewhere.

I'm not sure why you're having stability issues.
My Tiamat class is only 1400 tons heavier, a little slower, wider, more heavily armed, 450 tons less armor (differently arranged), and 1.15 stability with a slow & easy role.

Best guess is your hull is too narrow and too long.
Pennsylvania was 29.6m wide, you're only 28m.

On the Hull Tab - try clicking on Normal Tonnage. That will lock that.
Then go add 4m to the hull width and see what happens.
Your BC should plummet, your seakeeping may still be ok.

You may need to shave some deck armor further to make weight,
or since your hull speed is 24, but you're only going 22, you could reduce your hull length.

Ships like this make me wish we had a bathymetric map in use.
Historically the depth would impose a number of restrictions on different navies, the Aztec being one.

I've read the USN for a while limited the max depth as 7.5m to allow working off the mexican shore. Likewise the baltic is shallow, Suez wasn't yet passable to this depth, there were restrictions in Indonesia, and many harbors couldn't take deep hulls. All of which falls under the category of nitpicking record keeping Snip has saved you from :)

[Kaiser Kirk]

I still can't figure out why your ship was having it's problems.
I suspect the program is having a conniption fit over something.

Anyhow, I tried putting it in from scratch, and building the hull the Parthian way....short and beamy.
I got your ship down to 27,000 tons, good seakeeping, slow & easy roll, and 1.20 stability.

Chalchiuhticue, Aztec Parthian Gilgamesh laid down 1916

Displacement:
   27,000 t light; 28,795 t standard; 29,962 t normal; 30,895 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (535.99 ft / 524.93 ft) x 104.99 ft x (30.35 / 31.14 ft)
   (163.37 m / 160.00 m) x 32.00 m  x (9.25 / 9.49 m)

Armament:
      12 - 14.17" / 360 mm 45.0 cal guns - 1,435.21lbs / 651.00kg shells, 120 per gun
     Breech loading guns in turret on barbette mounts, 1916 Model
     4 x 3-gun mounts on centreline ends, evenly spread
      16 - 3.94" / 100 mm 50.0 cal guns - 33.07lbs / 15.00kg shells, 160 per gun
     Quick firing guns in deck and hoist mounts, 1916 Model
     16 x Single mounts on sides, evenly spread
      Weight of broadside 17,752 lbs / 8,052 kg

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   13.8" / 350 mm   341.21 ft / 104.00 m   13.12 ft / 4.00 m
   Ends:   4.72" / 120 mm   183.69 ft / 55.99 m   13.12 ft / 4.00 m
     Main Belt covers 100 % of normal length

   - Torpedo Bulkhead - Additional damage containing bulkheads:
      1.97" / 50 mm   341.21 ft / 104.00 m   29.10 ft / 8.87 m
   Beam between torpedo bulkheads 78.74 ft / 24.00 m

   - Hull void:
      0.00" / 0 mm     0.00 ft / 0.00 m   0.00 ft / 0.00 m

   - Gun armour:   Face (max)   Other gunhouse (avg)   Barbette/hoist (max)
   Main:   13.8" / 350 mm   6.30" / 160 mm      13.8" / 350 mm
   2nd:   2.95" / 75 mm   1.97" / 50 mm      2.95" / 75 mm

   - Protected deck - multiple decks:
   For and Aft decks: 4.72" / 120 mm
   Forecastle: 2.36" / 60 mm  Quarter deck: 2.36" / 60 mm

   - Conning towers: Forward 13.78" / 350 mm, Aft 0.00" / 0 mm

Machinery:
   Oil fired boilers, steam turbines,
   Electric motors, 4 shafts, 45,074 shp / 33,625 Kw = 22.00 kts
   Range 5,655nm at 12.00 kts
   Bunker at max displacement = 2,100 tons

Complement:
   1,138 - 1,480

Cost:
   £4.651 million / $18.604 million

Distribution of weights at normal displacement:
   Armament: 3,726 tons, 12.4 %
      - Guns: 3,726 tons, 12.4 %
   Armour: 10,870 tons, 36.3 %
      - Belts: 3,245 tons, 10.8 %
      - Torpedo bulkhead: 723 tons, 2.4 %
      - Armament: 3,314 tons, 11.1 %
      - Armour Deck: 3,301 tons, 11.0 %
      - Conning Tower: 286 tons, 1.0 %
   Machinery: 1,679 tons, 5.6 %
   Hull, fittings & equipment: 9,476 tons, 31.6 %
   Fuel, ammunition & stores: 2,961 tons, 9.9 %
   Miscellaneous weights: 1,249 tons, 4.2 %
      - Hull below water: 451 tons
      - Hull void weights: 300 tons
      - On freeboard deck: 100 tons
      - Above deck: 398 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     42,590 lbs / 19,319 Kg = 29.9 x 14.2 " / 360 mm shells or 7.2 torpedoes
   Stability (Unstable if below 1.00): 1.20
   Metacentric height 7.5 ft / 2.3 m
   Roll period: 16.1 seconds
   Steadiness   - As gun platform (Average = 50 %): 71 %
         - Recoil effect (Restricted arc if above 1.00): 0.64
   Seaboat quality  (Average = 1.00): 1.32

Hull form characteristics:
   Hull has a flush deck,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.627 / 0.630
   Length to Beam Ratio: 5.00 : 1
   'Natural speed' for length: 22.91 kts
   Power going to wave formation at top speed: 53 %
   Trim (Max stability = 0, Max steadiness = 100): 54
   Bow angle (Positive = bow angles forward): 10.00 degrees
   Stern overhang: 6.56 ft / 2.00 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
      - Forecastle:   20.00 %,  25.49 ft / 7.77 m,  23.85 ft / 7.27 m
      - Forward deck:   30.00 %,  23.85 ft / 7.27 m,  20.57 ft / 6.27 m
      - Aft deck:   35.00 %,  20.57 ft / 6.27 m,  20.57 ft / 6.27 m
      - Quarter deck:   15.00 %,  20.57 ft / 6.27 m,  20.57 ft / 6.27 m
      - Average freeboard:      21.85 ft / 6.66 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 94.4 %
      - Above water (accommodation/working, high = better): 147.6 %
   Waterplane Area: 41,333 Square feet or 3,840 Square metres
   Displacement factor (Displacement / loading): 96 %
   Structure weight / hull surface area: 200 lbs/sq ft or 975 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.91
      - Longitudinal: 2.29
      - Overall: 1.00
   Adequate machinery, storage, compartmentation space
   Excellent accommodation and workspace room
   Ship has slow, easy roll, a good, steady gun platform
   Good seaboat, rides out heavy weather easily

431t- Turbogenerators
20t - additional DC pumps

100t - flag facilities

373t - 1910 FC
25t - LR radio

Forecastle & Quarterdeck - single 60mm deck slopes and flat.

F/A Deck
Main Armored Deck : 100mm
Lower splinter deck : 20mm