why yamato cannot be built currently in game (armor weight)

[christian]

it seems several people (including me) have tried to build ships like the yamato which historically had really damn tough armor 

so i decided to run around a bit and throw armor on my ship and see how much it actually weighted and also pulled up a steel supplier who had a steel calculator for pieces of steel (assuming it uses standard steel density) 
www.maiak-m.bg/en/calculator/i1/Steel-sheets-and-plates.html 
so first i used this for the armor of the yamato which seems accurate i.imgur.com/6HPAB6f.jpg and also navypedia www.navypedia.org/ships/japan/jap_bb_yamato.htm

the deck which was 200mm thick being 39 meters wide and 105 meters long (taking into account the barbettes do not have armor over them) 

this gives 6430 tons which is quite heavy and is already a significant part of yamatos armor weight considering all her armor combined weighed 22k tons
but when building a 63200ton ship in game with an 8 inch deck considering deck armor weight scales with ship tonnage we will be taking the lowest weight for the yamato at 63200 tons
results are the deck armor only weights around 14971 tons which seems to indicate that armor in game weights A LOT more than it should

calculating the belt armor being 5.8 meters tall 410mm thick 105mm long it comes out at a weight of 1960 tons this surprises me a lot because i thought it would be way heavier so i went the calculator is probably broken
www.chapelsteel.com/weight-steel-plate.html
went and used this which pumped out almost the exact same number (had to convert to inches so i might have lost a few tonnes there) 

in short my conclusion from this is that armor weights too much compared to real life (im assuming armor to be pure steel of course) 


(this test was done with armor level 18 i suspect weight to be 2-6% lower with max tech on) 

although what interests me is how effective armor is at 17 ap tech and 18 armor tech a 14 inch gun can barely punch through 18.4 inches of plate at 5000 yards 
while in real life comparing it to a 14 inch gun in this example lets say the american 14 inch gun it has almost 5 inches less pen in game achieving 600 mm pen in real life (26 inches of armor)

im not sure if the higher weight of armor on ships was done to compensate for the fact guns now also perform worse or how it all fits together and il probably comment on how the gun and armor balance flows 

in real life the yamato was immune to itself from 20k yards to 30k yards if you take -1 18 inch guns all thats needed to make yourself immune to these guns is 12.5 inches of belt armor and 7 inches of roof armor (with lvl 17 ap tech and 18 armor tech of course this is probably gonna need to be thicker once you face +1 18 inch guns in fact i know it is gonna need to be thicker) whats interesting is that 16 +1 guns will penetrate 13 inches of belt thus 13 inches of belt is needed to survive 16+1 guns

also for some reason deck penetration has not been reduced significantly while deck penetration at long range has 

i think the new armor system of armor becoming more effective while also being lighter but still being far heavier than real life and guns performing worse than they should are confusing people quite a bit

[pedroig]

1. For the Yamato and Iowa class ships they used RHA armour, which is steel made to MIL-DTL-46177, today's equivalent would be 4340, which does have a different density than 10 series steel, 1030 being probably the most common steel out there currently.

2. You are discounting the superstructure required to support said armour, in your weight calculations, still not enough to make up for the entire difference, but makes it closer than what one may think.

3. There are many confusing design decisions in the game, but at least they are consist throughout. It doesn't really take into account what else is around the armour, or where the belt actually is on a given class. Overall, it would be better to do a backwards conversion of RHA equivalency to KCA and then use RHA penetration values for the projectiles. Which would better explain why for example a 105 mm gun can have better RHA penetration over a 150 mm gun.

Also interesting read:


USN Test results of Shinano Turret Armor

[elouda]

Remember that belt will also include fore and aft belt bulkheads, and on Yamato these were part of the 'hexagonal' citadel structure so will weigh somewhat more than simple flat ones. Also note Yamato's belt is inclined 20 degrees, so 5.8m high belt is going to be ~6.17m in its 'height' dimension.

Some quick estimates;
General armour weight estimate = 40lb per in per sqft = 40lb/144in3 = 0.2778lb/in3 = ~7670kg/m3 which is fairly close to 4340 (~7850kg/m3), so lets split the difference at 7750kg/m3.

Belt = 6.17m high x ~110m long x 0.41m thick = 278m3 = 2156 tons
Belt ends = ~6.5m high x ~45m long (hexagon) x 0.29m thick = 85m3 = 675 tons
Lower belt = ~8m high x 110m long x ~0.16m (average) = 140m3 = 1091 tons
This is a total of about ~3900 tons

Deck = ~115m (hex - barbettes) x ~34.5m x ~0.22m = 873m3 = 6765 tons
Upper deck = ~150m x ~34.5m x ~0.04m = 207m3 = 1604 tons
Total of about ~8400 tons

These two add up to around ~12300 tons, which is about ~55% of the total armour weight of 22500-23000t. Accounting for the additional bulkheads, the 'bottom' armour under the magazines, etc. will probably add up to another few thousand. This means structural support for the armour is going to be another ~8000-9000 tons, or about ~35-40% of the total.

[christian]

May 25, 2019 9:49:13 GMT -6 pedroig said:

1. For the Yamato and Iowa class ships they used RHA armour, which is steel made to MIL-DTL-46177, today's equivalent would be 4340, which does have a different density than 10 series steel, 1030 being probably the most common steel out there currently.

2. You are discounting the superstructure required to support said armour, in your weight calculations, still not enough to make up for the entire difference, but makes it closer than what one may think.

3. There are many confusing design decisions in the game, but at least they are consist throughout. It doesn't really take into account what else is around the armour, or where the belt actually is on a given class. Overall, it would be better to do a backwards conversion of RHA equivalency to KCA and then use RHA penetration values for the projectiles. Which would better explain why for example a 105 mm gun can have better RHA penetration over a 150 mm gun.

Also interesting read:


USN Test results of Shinano Turret Armor

regarding the "superstructure" which in reality is support of the armor should not be counted as armor in the first place when the game considers 1 inch armor (usually just regarded as structural parts of hull outer plating if this was the case the yamatos armor tonnage would skyrocket 

in the first place its important to note that either way armor in game is heavier than it was in real life they could reasonably make a yamato in 1937 with the insane amount of armor as shown in real life even to the point of them giving it bottom citadelle armor (which no other ships had to the same extent yamato had 80mm) and only weighing in at 63200 tons yet in game with that tonnage we cannot do the same 

also the fact that the structure for the ship already seems to be built 
for example on a 63200 ton hull you get 47515 tons to play with totally clean no machinery nothing which means there is already over 16k tons of pure structure to support said armor 

do keep in mind most penetration formulas on american guns are based on the usn standard penetration formula 

yamatos armor is indeed interesting especially the fact the turrets are literally impenetrable by anything which is what im trying to do in game

i wish the game was more realistic in terms of armor weight because as far as i can see not taking into account any of the 32 mm plating or the 50mm decks to prevent deck damage from muzzle blast the superstructure armor the superstructure weight at all or nothing else of the ship the ships in game seem to weight WAYYY TOO MUCH which honestly dissapoints me because i was hoping to be able to make massive ships of doom

also the underperformance of 17 inch + guns really annoys me specifically the 20 inch guns which weight twice as much as 16 inch guns if not more yet barely have 3 inches more pen when in real life these guns approached 1000mm of rha pen

[alexbrunius]

May 25, 2019 10:29:15 GMT -6 elouda said:

Remember that belt will also include fore and aft belt bulkheads, and on Yamato these were part of the 'hexagonal' citadel structure so will weigh somewhat more than simple flat ones.

Actually the hexagonal sides shorten the length of the belt compared to a flat citadel / 90 degree angles and makes it overall lighter. The most optimal theoretical shape to minimize armor weight and maximize volume covered is a circle/sphere and hexagon sides are closer to this than a square/box shape.

[christian]

May 25, 2019 11:06:34 GMT -6 alexbrunius said:

May 25, 2019 10:29:15 GMT -6 elouda said:

Remember that belt will also include fore and aft belt bulkheads, and on Yamato these were part of the 'hexagonal' citadel structure so will weigh somewhat more than simple flat ones.

Actually the hexagonal sides shorten the length of the belt compared to a flat citadel and makes it overall lighter. The most optimal shape is a circle and hexagon is closer to this than a square.

good point that is actually the case so what could be done was extend the belt as if it was totally flat and the ends were also flat and then take that as the "real" number


4853 tons
is the total weight for 2 plates being perfectly straight going from 60 to 190 on the scale aka covering all the barbettes and giving the same cover as the wierd shaped citadelle

this number is higher than it else would be especially because the shapes on the end of the citadelle are not 410mm thick and are 300-330mm thick 

[elouda]

May 25, 2019 11:06:34 GMT -6 alexbrunius said:

May 25, 2019 10:29:15 GMT -6 elouda said:

Remember that belt will also include fore and aft belt bulkheads, and on Yamato these were part of the 'hexagonal' citadel structure so will weigh somewhat more than simple flat ones.

Actually the hexagonal sides shorten the length of the belt compared to a flat citadel / 90 degree angles and makes it overall lighter. The most optimal theoretical shape to minimize armor weight and maximize volume covered is a circle/sphere and hexagon sides are closer to this than a square/box shape.

They shorten the length of the belt, but they increase the length of the end bulkheads - thats why I used ~110m for the belt length instead of the full citadel length of ~135m, and used ~45m instead of ~34m for the end lengths.

[christian]

May 25, 2019 10:29:15 GMT -6 elouda said:

Remember that belt will also include fore and aft belt bulkheads, and on Yamato these were part of the 'hexagonal' citadel structure so will weigh somewhat more than simple flat ones. Also note Yamato's belt is inclined 20 degrees, so 5.8m high belt is going to be ~6.17m in its 'height' dimension.

Some quick estimates;
General armour weight estimate = 40lb per in per sqft = 40lb/144in3 = 0.2778lb/in3 = ~7670kg/m3 which is fairly close to 4340 (~7850kg/m3), so lets split the difference at 7750kg/m3.

Belt = 6.17m high x ~110m long x 0.41m thick = 278m3 = 2156 tons
Belt ends = ~6.5m high x ~45m long (hexagon) x 0.29m thick = 85m3 = 675 tons
Lower belt = ~8m high x 110m long x ~0.16m (average) = 140m3 = 1091 tons
This is a total of about ~3900 tons

Deck = ~115m (hex - barbettes) x ~34.5m x ~0.22m = 873m3 = 6765 tons
Upper deck = ~150m x ~34.5m x ~0.04m = 207m3 = 1604 tons
Total of about ~8400 tons

These two add up to around ~12300 tons, which is about ~55% of the total armour weight of 22500-23000t. Accounting for the additional bulkheads, the 'bottom' armour under the magazines, etc. will probably add up to another few thousand. This means structural support for the armour is going to be another ~8000-9000 tons, or about ~35-40% of the total.

first of all the deck is not 220 mm thick its 200 mm thick 
second of all the belt armor is not 6.17 meters high its 5.8 meter high angled the PLATE itself is 5.8 meters tall which means sloped it reaches less than 5.8 meters up

structural support for armor is not considered in the armor weight at all no nation does this and nobody will ever do it because it makes no sense having things which are inherently not armor count as armor (unless you consider structural steel armor)

armor weight of a ship in tonnage is the pure weight of the armor plates nothing else this means sure the 410mm plate might not be able to sit there without support but the support is still not counted as armor weight this means in the 22k tons armor that support is not counted

in addition to this its worth nothing the yamatos armor is surprisingly structurally well made to save on weight of the armor

also the fact that when you create a battleship in game you do not have acces to a large amount of the tonnage on a 63200 ton ship you have acces to 47000 tons which means 16k tons go to crew structure watertight compartments and whatever else the ship needs im quessing this is also general ships sturcture

armor structure is not accounted for and still does not fix the problem that is being unable to build ships as heavily armored in real life by a large amount 

also your completely forgetting the turret the aft rudder house the conning tower which is coated in 500mm thick armor and the barbettes probably weighting more than the belt armor combined 

the barbettes are extremely thick are very large and likely weight alot 

also the turrets themselves the gun houses weight alot and compromise over half the turrets weight and the 50-30mm plating added to stop the guns from blasting the deck the secondary gun armor the superstructure armor and so on all adds up the plating on the outside (32mm) in that 22k armor weight there is absolutely 0 room for structural support for the armor 

[christian]

also i noticed a comment someone else made so i will post it here because it has major significance



"Okay. I am testing around abit quickly to figure out how the armor formulas in RTW2 works.

Starting out with 1920 start UK and a 5000 ton ship that is given 10 inch belt armor we get that the armor weight is given as 1687 ton.
Now if we try to make a ship that is 8 times as large 40000 ton we get that the armor weight is given as 5589 ton ( 3.313 times that of the 8 times smaller tonnage ship )
If we compare 10000 ton vs 80000 ton and same belt we get 2538 ton vs 10960 ton ( 4.32 times that of the 8 times smaller tonnage ship )

Comparing deck armor for a 5000 ton ship and 10 inch deck we get 4576 ton. An 8 times larger 40000 ton ship with 10 inch deck get 14869 ton ( 3.2 times that of the 8 times smaller tonnage ship )

Comparing deck armor for a 10000 ton ship and 10 inch deck we get that the armor weight is given as 6889 ton.
The same ship that is 8 times as large 80000 ton we get that the armor weight is given as 29159 ton ( 4.23 times that of the 8 times smaller tonnage ship )


Let's now look at even thicker armor.
20 inch belt on 10000 ton ship gives us 5076 tons of armor
20 inch belt on 80000 ton ship gives us 21921 tons of armor ( 4.32 times that of the 8 times smaller tonnage ship, identical to the ratio increase with 10 inch belt )
We can also see that 20 inch armor yields exactly 2 times as heavy armor as 10 inch armor would, which is to be expected for the same tonnage of ship.


In a perfect 100% theoretical world where all hull shapes were identical we would expect all these ratios were exactly 4.0 ( area scale for 8x volume ).


Based on these findings it seems to me that the increase in armor weight as tonnage increases is overly favorable to "smaller" tonnages of ships ( 5000-20000 tons ), and overly punishing towards larger tonnages of ships ( above 40000 ). I want to return and do a more detailed breakdown with smaller intervals later when I have time to spare."

comment was by alexbrunius he deserves all ze praise for this

[amurtiger]

May 25, 2019 9:49:13 GMT -6 pedroig said:

1. For the Yamato and Iowa class ships they used RHA armour, which is steel made to MIL-DTL-46177, today's equivalent would be 4340, which does have a different density than 10 series steel, 1030 being probably the most common steel out there currently.

In practical terms the density of 4340 and 1030 steels are exactly the same ( 7.85 g/cm3 ), any problems the Japanese might have had in making better ( or merely different ) quality armor would not have offered a weight benefit in terms of weight saving.

[elouda]

May 25, 2019 11:17:43 GMT -6 christian said:

May 25, 2019 10:29:15 GMT -6 elouda said:

Remember that belt will also include fore and aft belt bulkheads, and on Yamato these were part of the 'hexagonal' citadel structure so will weigh somewhat more than simple flat ones. Also note Yamato's belt is inclined 20 degrees, so 5.8m high belt is going to be ~6.17m in its 'height' dimension.

Some quick estimates;
General armour weight estimate = 40lb per in per sqft = 40lb/144in3 = 0.2778lb/in3 = ~7670kg/m3 which is fairly close to 4340 (~7850kg/m3), so lets split the difference at 7750kg/m3.

Belt = 6.17m high x ~110m long x 0.41m thick = 278m3 = 2156 tons
Belt ends = ~6.5m high x ~45m long (hexagon) x 0.29m thick = 85m3 = 675 tons
Lower belt = ~8m high x 110m long x ~0.16m (average) = 140m3 = 1091 tons
This is a total of about ~3900 tons

Deck = ~115m (hex - barbettes) x ~34.5m x ~0.22m = 873m3 = 6765 tons
Upper deck = ~150m x ~34.5m x ~0.04m = 207m3 = 1604 tons
Total of about ~8400 tons

These two add up to around ~12300 tons, which is about ~55% of the total armour weight of 22500-23000t. Accounting for the additional bulkheads, the 'bottom' armour under the magazines, etc. will probably add up to another few thousand. This means structural support for the armour is going to be another ~8000-9000 tons, or about ~35-40% of the total.

first of all the deck is not 220 mm thick its 200 mm thick 
second of all the belt armor is not 6.17 meters high its 5.8 meter high angled the PLATE itself is 5.8 meters tall which means sloped it reaches less than 5.8 meters up

I used 220mm because as it says at the beginning, its a rough estimate. 220mm accounts for both the 230mm sections, as well as the sloped sections adding extra weight without having to factor that in. Just using 200mm will lowball it massively.

Generally when belt heights are given they are line of sight heights as part of the ships freeboard and draught, sometimes listed also as how much is above and below the waterline at specific loading conditions. In this case I don't have a detailed enough diagram of Yamato's scheme to make an estimation if this is the case here, but feel free to use 5.8m in there if you want to.

structural support for armor is not considered in the armor weight at all no nation does this and nobody will ever do it because it makes no sense having things which are inherently not armor count as armor (unless you consider structural steel armor)

armor weight of a ship in tonnage is the pure weight of the armor plates nothing else this means sure the 410mm plate might not be able to sit there without support but the support is still not counted as armor weight this means in the 22k tons armor that support is not counted

Do you actually have anything to base this assumption on? Certainly the bracing, rivets, etc. to hold those plates in place is accounted for, it would not be a stretch to also include any additional structural reinforcement where needed to support that armour weight.

also the fact that when you create a battleship in game you do not have acces to a large amount of the tonnage on a 63200 ton ship you have acces to 47000 tons which means 16k tons go to crew structure watertight compartments and whatever else the ship needs im quessing this is also general ships sturcture

Yes, that is because there's this portion of a ship called the 'hull' which takes up a fair bit of weight. USN design studies generally allotted something like ~40% of displacement to the hull and fittings (~15200t out of 32000t for the New Mexico for example, or ~19400t out of 42500t for the 1920s South Dakota).

also your completely forgetting the turret the aft rudder house the conning tower which is coated in 500mm thick armor and the barbettes probably weighting more than the belt armor combined

the barbettes are extremely thick are very large and likely weight alot

also the turrets themselves the gun houses weight alot and compromise over half the turrets weight and the 50-30mm plating added to stop the guns from blasting the deck the secondary gun armor the superstructure armor and so on all adds up the plating on the outside (32mm) in that 22k armor weight there is absolutely 0 room for structural support for the armor

Turrets - generally turret armour is accounted for as part of armament weight, and RTW also follows this convention.

Aft rudder house & conning tower - See "Accounting for the additional bulkheads, the 'bottom' armour under the magazines, etc. will probably add up to another few thousand" - both of these are rather small despite being well protected, so will fit inside that estimate

Barbettes - this is actually a good catch, see below for estimate

Upper 50-30mm deck - Accounted for, see original post

Secondary gun armour - Again, typically considered armament weight. Secondary gun barbettes are thin enough to fit into the overhead the conning tower, etc. fit into

Superstructure - Yamato has no armoured superstructure. This is all hull & fittings weight.

Hull plating - See above about hull & fittings. Not armour.

Barbettes;

Rough estimate puts them at ~14.5m diameter & ~3.4m height below deck and ~1m/3.5m height above deck (AY/B). At ~410mm below deck and 560mm above deck. This gives a total volume of ~65.3m3 per turret below deck, and ~26.5m3 for A/Y above deck, and ~90m3 for B. This a total of ~339m3 for the 3 turrets, which is about ~2630 tons.

[christian]

May 25, 2019 12:14:01 GMT -6 elouda said:

May 25, 2019 11:17:43 GMT -6 christian said:

first of all the deck is not 220 mm thick its 200 mm thick 
second of all the belt armor is not 6.17 meters high its 5.8 meter high angled the PLATE itself is 5.8 meters tall which means sloped it reaches less than 5.8 meters up

I used 220mm because as it says at the beginning, its a rough estimate. 220mm accounts for both the 230mm sections, as well as the sloped sections adding extra weight without having to factor that in. Just using 200mm will lowball it massively.

Generally when belt heights are given they are line of sight heights as part of the ships freeboard and draught, sometimes listed also as how much is above and below the waterline at specific loading conditions. In this case I don't have a detailed enough diagram of Yamato's scheme to make an estimation if this is the case here, but feel free to use 5.8m in there if you want to.

structural support for armor is not considered in the armor weight at all no nation does this and nobody will ever do it because it makes no sense having things which are inherently not armor count as armor (unless you consider structural steel armor)

armor weight of a ship in tonnage is the pure weight of the armor plates nothing else this means sure the 410mm plate might not be able to sit there without support but the support is still not counted as armor weight this means in the 22k tons armor that support is not counted

Do you actually have anything to base this assumption on? Certainly the bracing, rivets, etc. to hold those plates in place is accounted for, it would not be a stretch to also include any additional structural reinforcement where needed to support that armour weight.

also the fact that when you create a battleship in game you do not have acces to a large amount of the tonnage on a 63200 ton ship you have acces to 47000 tons which means 16k tons go to crew structure watertight compartments and whatever else the ship needs im quessing this is also general ships sturcture

Yes, that is because there's this portion of a ship called the 'hull' which takes up a fair bit of weight. USN design studies generally allotted something like ~40% of displacement to the hull and fittings (~15200t out of 32000t for the New Mexico for example, or ~19400t out of 42500t for the 1920s South Dakota).

also your completely forgetting the turret the aft rudder house the conning tower which is coated in 500mm thick armor and the barbettes probably weighting more than the belt armor combined

the barbettes are extremely thick are very large and likely weight alot

also the turrets themselves the gun houses weight alot and compromise over half the turrets weight and the 50-30mm plating added to stop the guns from blasting the deck the secondary gun armor the superstructure armor and so on all adds up the plating on the outside (32mm) in that 22k armor weight there is absolutely 0 room for structural support for the armor

Turrets - generally turret armour is accounted for as part of armament weight, and RTW also follows this convention.

Aft rudder house & conning tower - See "Accounting for the additional bulkheads, the 'bottom' armour under the magazines, etc. will probably add up to another few thousand" - both of these are rather small despite being well protected, so will fit inside that estimate

Barbettes - this is actually a good catch, see below for estimate

Upper 50-30mm deck - Accounted for, see original post

Secondary gun armour - Again, typically considered armament weight. Secondary gun barbettes are thin enough to fit into the overhead the conning tower, etc. fit into

Superstructure - Yamato has no armoured superstructure. This is all hull & fittings weight.

Hull plating - See above about hull & fittings. Not armour.

Barbettes;

Rough estimate puts them at ~14.5m diameter & ~3.4m height below deck and ~1m/3.5m height above deck (AY/B). At ~410mm below deck and 560mm above deck. This gives a total volume of ~65.3m3 per turret below deck, and ~26.5m3 for A/Y above deck, and ~90m3 for B. This a total of ~339m3, which is about ~2630 tons.

if we consider hull plating and the 25mm superstructure not armor then where do we draw the line between structure and armor 
either way it dosent change the fact armor weights to much even with structural support im ending up at over 30k tons for armor 

in addition to this according to the math if we take 3 barbettes and the armor calculations you did aka 2630x3 + 12300 tons we end up at 20k tons which basically ensures that the yamato armor was not with structure included

[elouda]

May 25, 2019 13:29:19 GMT -6 christian said:

if we consider hull plating and the 25mm superstructure not armor then where do we draw the line between structure and armor 
either way it dosent change the fact armor weights to much even with structural support im ending up at over 30k tons for armor 

in addition to this according to the math if we take 3 barbettes and the armor calculations you did aka 2630x3 + 12300 tons we end up at 20k tons which basically ensures that the yamato armor was not with structure included

I'm not disagreeing that armour is too heavy! Just trying to get a more accurate sense of how Yamatos protection breaks down.

On the flip side, Hull & Fittings is probably too light.

The total of 2630t was for all 3 barbettes, should probably have been clearer about that.

[christian]

May 25, 2019 13:33:52 GMT -6 elouda said:

May 25, 2019 13:29:19 GMT -6 christian said:

if we consider hull plating and the 25mm superstructure not armor then where do we draw the line between structure and armor 
either way it dosent change the fact armor weights to much even with structural support im ending up at over 30k tons for armor 

in addition to this according to the math if we take 3 barbettes and the armor calculations you did aka 2630x3 + 12300 tons we end up at 20k tons which basically ensures that the yamato armor was not with structure included

I'm not disagreeing that armour is too heavy! Just trying to get a more accurate sense of how Yamatos protection breaks down.

On the flip side, Hull & Fittings is probably too light.

The total of 2630t was for all 3 barbettes, should probably have been clearer about that.

yeah ok makes sense then

although it is to be noted hull playing technically counts as armor (surface level coating) for example the brooklyn was covered in 16mm antifragmentation armor

either way armor needs to be reduced a bit in weight its a bit funky 

[archelaos]

May 25, 2019 13:33:52 GMT -6 elouda said:

May 25, 2019 13:29:19 GMT -6 christian said:

if we consider hull plating and the 25mm superstructure not armor then where do we draw the line between structure and armor 
either way it dosent change the fact armor weights to much even with structural support im ending up at over 30k tons for armor 

in addition to this according to the math if we take 3 barbettes and the armor calculations you did aka 2630x3 + 12300 tons we end up at 20k tons which basically ensures that the yamato armor was not with structure included

I'm not disagreeing that armour is too heavy! Just trying to get a more accurate sense of how Yamatos protection breaks down.

On the flip side, Hull & Fittings is probably too light.

The total of 2630t was for all 3 barbettes, should probably have been clearer about that.

Springsharp gives about 24k ton as hull and fittings, but much lower armour weights. Remember also that fuel is around 6k ton.