Japanese 20inch (510mm) guns

[Chris Loosa]

I was wondering if there is a possibility of the Japanese receiving the 20 inch double barrel turrets that was planned for the next generation design of the yamato class battleships. Shikishima was going to be the first of its kind designated the A-150 class of battleship for the Japanese.

Edited September 7, 2020 by Chris Loosa

[TsAGI]

Not just the Japanese but also the Germans had plans for 50.8cm guns for their H44 class. Maybe this could be an Axis wonder weapon quirk where they have access to bigger guns?

[draconins]

While I love to have this, I think this should be part of future minor update. However I have complaint if Shikishima name being used, as it is very fictional name for A150, and only used in WoW to my knowledge. This is especially more so for a ship which already lead for the class for pre dreadnought battleship which is covered in timeline of UAD.

Most reference of probable actual name A-150 would be either Omi or Kii. Kii basically a planned lead ship name which is originally planned for other old ship though it was cancelled due to washington treaty. Omi is another name in that class which was cancelled. Kii is also probable name of cancelled fourth Yamato class.

 

[Cptbarney]

1 hour ago, draconins said:

While I love to have this, I think this should be part of future minor update. However I have complaint if Shikishima name being used, as it is very fictional name for A150, and only used in WoW to my knowledge. This is especially more so for a ship which already lead for the class for pre dreadnought battleship which is covered in timeline of UAD.

Most reference of probable actual name A-150 would be either Omi or Kii. Kii basically a planned lead ship name which is originally planned for other old ship though it was cancelled due to washington treaty. Omi is another name in that class which was cancelled. Kii is also probable name of cancelled fourth Yamato class.

 

https://en.wikipedia.org/wiki/Japanese_battleship_Shikishima

No it isn't. The name has been used before, Japanese BB's are named after provinces or alternate names of japan, i guess you can use mountains as well but those were for battlecruisers and CV's (1943).

https://en.wikipedia.org/wiki/Japanese_ship-naming_conventions

Fourth name for the yammy would of been izumo, settsu. if we go by how the ships were named (yamato central province, musashi east sea, shinano east mountain, next probs would of been echigo or wakaza if we go by the order they did it in).

Also reusing names has been thing for a long time now, theres only soo many names you can use before having to reuse them, shikashima is fine, but i prefer settsu or echigo. Fits in nicer.

[draconins]

4 hours ago, Cptbarney said:

https://en.wikipedia.org/wiki/Japanese_battleship_Shikishima

No it isn't. The name has been used before, Japanese BB's are named after provinces or alternate names of japan, i guess you can use mountains as well but those were for battlecruisers and CV's (1943).

Sorry I don't understand what do you mean here? What I am saying is that Shikishima is lead class already existing ships. I had many referring to name of Kii or Omi as possible name either for 4th Yamato or new A-150, and the names were already planned to be used for cancelled ships. Both were old provinces of Japan and does fit into convention.

4 hours ago, Cptbarney said:

https://en.wikipedia.org/wiki/Japanese_ship-naming_conventions

 

Fourth name for the yammy would of been izumo, settsu. if we go by how the ships were named (yamato central province, musashi east sea, shinano east mountain, next probs would of been echigo or wakaza if we go by the order they did it in).

 

Also reusing names has been thing for a long time now, theres only soo many names you can use before having to reuse them, shikashima is fine, but i prefer settsu or echigo. Fits in nicer.

Based on what Wakaza being suggested? I have heard Echigo but that was mainly fandom, but i read this was suggested as 5th Yamato (Kai Yamato), planned as improved shinano/Yamato, referred as hull 797, this was superseded by A-150 design. Battleship Settsu already used and actually active as "target ship" during world war II, so I doubt it would be using this name.  If you use wiki, Kii is even listed as 4th Yamato in https://en.wikipedia.org/wiki/Yamato-class_battleship

Also I am pretty sure that Izumo would not be used, she is active cruiser/training ship (from 1943) at world war II.

For name, I think they can repeat but there are so many old provinces name has not yet been used. Even just old name of japan many has not yet been used, for example

• Oyashima/Yashima
• Akitsukuni
• Mizuho (this actually used even for a seaplane carrier)
• Hinomoto

Also Fujimi made Kii as name for their model for A-150.

[Cptbarney]

8 minutes ago, draconins said:

Sorry I don't understand what do you mean here? What I am saying is that Shikishima is lead class already existing ships. I had many referring to name of Kii or Omi as possible name either for 4th Yamato or new A-150, and the names were already planned to be used for cancelled ships. Both were old provinces of Japan and does fit into convention.

Based on what Wakaza being suggested? I have heard Echigo but that was mainly fandom, but i read this was suggested as 5th Yamato (Kai Yamato), planned as improved shinano/Yamato, referred as hull 797, this was superseded by A-150 design. Battleship Settsu already used and actually active as "target ship" during world war II, so I doubt it would be using this name.  If you use wiki, Kii is even listed as 4th Yamato in https://en.wikipedia.org/wiki/Yamato-class_battleship

Also I am pretty sure that Izumo would not be used, she is active cruiser/training ship (from 1943) at world war II.

For name, I think they can repeat but there are so many old provinces name has not yet been used. Even just old name of japan many has not yet been used, for example

• Oyashima/Yashima
• Akitsukuni
• Mizuho (this actually used even for a seaplane carrier)
• Hinomoto

Also Fujimi made Kii as name for their model for A-150.

Well i didn't see the name for Kii at first, although no one can be certain if that was the name she would of had, unless echigo was intended for the fifth yammy. regardlessthe  A-150 is a different ship entirely (different guns, armour, internals, secondary layout, equipment etc), only due to the japanese burning the documents we aren't able to decern what she would of been named as so reusing names isn't a problem at all.

Shikashima is used in a patrol boat today so reusing lead ship names isn't a problem at all. They could of used settsu for the fifth name (for yammy) if they really wanted too maybe to give it a new lease of life, but i guess they probs would of used echigo or maybe Aki. I mean queen elizabeth was the name for a class of battleships is now being used for a new class of CV's so lead class wouldn't alter that at all.

Also it was owari that was the sister ship for kii not omi. Regardless none of this matters anyways if we don't get 20.1inches since then we can't make any A-150 BB's.

At least i learnt something new though never knew izumo was even used then although her name as the fifth yammy or if japan could a sixth yammy wouldn't be unusual or strange, im not against kii however seeing her and a few times even playing with her in wows as a BB and here as a super bb would be somewhat werid, but oh well.

Oh and strangely enough wargaming choose Yashima as the name for the A-150 but got rid of it because they thought it sounded and looked too much like shimakaze. So they change it to Shikashima, but the name seems to have grown on me.

I like too see up to 533mm guns but i know that won't happen for obvious reasons (maybe if we push enough).

[draconins]

Owari is indeed second named Kii class, however third and fourth planned were Suruga and Omi, though not yet had formal "naming". Both are old provinces of Japan. In english wiki this is not present, but checking japanese wiki, it is there https://ja.wikipedia.org/wiki/紀伊型戦艦 .  Also in https://www.navypedia.org/ships/japan/jap_bb_kii.htm.

The name itself indeed used in the future as Minesweeper and Supply ship. Suruga itself is another possible name for the improved Yamato. Other possible names are Harima and Iyo, both to my knowledge never used in Japanese military ship.

On reusing the name IJN probably can, but likelihood is low given relatively "new" the naming standard at the time, and as I said there are too many names still not yet used, not to mention IJN has some names which is almost being used but cancelled. IJN may even actually planned use Owari for that, but yes this is speculation. However, I believe Shikishima is kind of bad speculation and mainly I do not want confusion in UAD with the old actual class Shikishima, if they somehow make premade library for it. Historical reuse for IJN I can remember were Azuma, Kongou, Fuso, Hiei, Ryujo, but those were ironclads. Those name were reused in completely different vessel and military era, Ryujo and Azuma not even following the convention. Shikishima is also basically still used as training though already stricken but not scrapped until after the war. From available previous name, it would rather make more sense to reuse Asahi (sunk since 1942) as it is another poetic name for Japan, the name itself is now reused twice already by after war Japan .

On the topic of big gun I think while it is nice to have I would rather the main issues (especially formation) fixed and other main features added first. This large gun probably can be added relatively easy as minor update but likely mostly imply increasing cosmetic size and stat. And even prior this, the quad guns.

Nonetheless bigger gun is nice once they begin working into tech higher than 1940, eg 1945.

For the thread starter, sorry for being off-topic.

[Bluishdoor76]

10 hours ago, Cptbarney said:

Also reusing names has been thing for a long time now, theres only soo many names you can use before having to reuse them, shikashima is fine, but i prefer settsu or echigo. Fits in nicer.

How many Enterprise's have there been so far? like 4 or something around that?

the US army is the worse when it comes to naming equipment tho :P

[slayer6]

On 9/8/2020 at 3:03 PM, TsAGI said:

Not just the Japanese but also the Germans had plans for 50.8cm guns for their H44 class. Maybe this could be an Axis wonder weapon quirk where they have access to bigger guns?

That quirk could also include the drawback of their FCS being knocked out easier...

[TsAGI]

On 9/19/2020 at 1:32 PM, slayer6 said:

That quirk could also include the drawback of their FCS being knocked out easier...

Did Japan have that problem too? I know Bismarck knocked her radar clean off with the blast of her 15" guns

[draconins]

On 9/21/2020 at 3:11 AM, TsAGI said:

 I know Bismarck knocked her radar clean off with the blast of her 15" guns

The search radar specifically, not whole radar set. Other including FCS were intact until the tower being destroyed by direct fire in later action.

 

On 9/21/2020 at 3:11 AM, TsAGI said:

Did Japan have that problem too?

IJN knew the blast effect early on, and many of its equipment placed, hardened, tested, or shielded for this problem. There was a 28 October 1942 Musashi test trial, which include the testing of newly equipped radar, (not september 1942 as some other source says). During the trials the radar display is damaged by gun blast. This was fixed by at least November for second trial on 28 November 1942. No further report of blast damage on radar in Yamato or Musashi after this. Source http://www.combinedfleet.com/musashi.htm

Also most Yamato radar antenna and primary FCS set is very high compared to Bismarck. Bismarck's first and third radar sits relatively low about 3m above  and 15m behind turret, while second is approximately 15m above turret. For comparison, Yamato the prominent search radar sits approximately 20 meter above top of turret and 20m behind the turret. Blast pressure measured during trials at Kamegakubi test range was 7.0 kg/cm2 (100 psi) at a point 15 m (50 feet) in front of the muzzle.

 

[TsAGI]

6 hours ago, draconins said:

The search radar specifically, not whole radar set. Other including FCS were intact until the tower being destroyed by direct fire in later action.

 

IJN knew the blast effect early on, and many of its equipment placed, hardened, tested, or shielded for this problem. There was a 28 October 1942 Musashi test trial, which include the testing of newly equipped radar, (not september 1942 as some other source says). During the trials the radar display is damaged by gun blast. This was fixed by at least November for second trial on 28 November 1942. No further report of blast damage on radar in Yamato or Musashi after this. Source http://www.combinedfleet.com/musashi.htm

Also most Yamato radar antenna and primary FCS set is very high compared to Bismarck. Bismarck's first and third radar sits relatively low about 3m above  and 15m behind turret, while second is approximately 15m above turret. For comparison, Yamato the prominent search radar sits approximately 20 meter above top of turret and 20m behind the turret. Blast pressure measured during trials at Kamegakubi test range was 7.0 kg/cm2 (100 psi) at a point 15 m (50 feet) in front of the muzzle.

 

Do you have a source for the second part? If it's a lengthy book or journal I would like to read more about it myself

[draconins]

15 hours ago, TsAGI said:

Do you have a source for the second part? If it's a lengthy book or journal I would like to read more about it myself

I assume positioning of radar? If you have correctly scaled drawing of Yamato and Bismarck, and know the positions of the radars you can measure its position. The search radars actually prominent enough. You can use anatomy of the ship book for both of them (Anatomy of the ship : Janusz Skulski and  Bismarck: Stefan Draminski and Anatomy of the ship: Battleship Bismarck by Stefan Draminski). The Yamato one has new edition with some additional (and some removed) called Battleships Yamato and Musashi (Anatomy of The Ship).

Both are physical books, and not really lengthy as it is mostly drawings. For Yamato drawing though, I prefer "Super Illustration: Imperial Japanese Navy Battleship Yamato". The scale drawing for external look is larger and more detailed. However if your interest is on internal layout, the anatomy of the ship series would be much better.

If you mean about blast pressure of Yamato guns, you can see http://www.navweaps.com/Weapons/WNJAP_18-45_t94.php.

[TsAGI]

On 9/24/2020 at 2:18 AM, draconins said:

I assume positioning of radar? If you have correctly scaled drawing of Yamato and Bismarck, and know the positions of the radars you can measure its position. The search radars actually prominent enough. You can use anatomy of the ship book for both of them (Anatomy of the ship : Janusz Skulski and  Bismarck: Stefan Draminski and Anatomy of the ship: Battleship Bismarck by Stefan Draminski). The Yamato one has new edition with some additional (and some removed) called Battleships Yamato and Musashi (Anatomy of The Ship).

Both are physical books, and not really lengthy as it is mostly drawings. For Yamato drawing though, I prefer "Super Illustration: Imperial Japanese Navy Battleship Yamato". The scale drawing for external look is larger and more detailed. However if your interest is on internal layout, the anatomy of the ship series would be much better.

If you mean about blast pressure of Yamato guns, you can see http://www.navweaps.com/Weapons/WNJAP_18-45_t94.php.

Oooh thanks a lot!

[Joryl]

you can also literally tour the full Yamato in VR including below deck which is quite awesome. 

 

[ReefKip]

20 inch seems interesting. However IRL it was an impractical caliber size. For what you need a 20inch that an 18 inch could not perform equally well? You just smash the target harder that would have been smashed by 18inch already.

Wanna see how quadruple turret 20 inch will work. Must be one hell of a recoil system to handle those firing at the same time. Which the game does not take into account. Yamato was already  forced to riple fire because the pressure from the recoil of all the guns firing was simply to much for the ship to handle.

Edited October 12, 2020 by ReefKip

[TsAGI]

10 hours ago, ReefKip said:

20 inch seems interesting. However IRL it was an impractical caliber size. For what you need a 20inch that an 18 inch could not perform equally well? You just smash the target harder that would have been smashed by 18inch already.

Wanna see how quadruple turret 20 inch will work. Must be one hell of a recoil system to handle those firing at the same time. Which the game does not take into account. Yamato was already  forced to riple fire because the pressure from the recoil of all the guns firing was simply to much for the ship to handle.

If all dimensions are proportional it would be about 37% heavier. But then you would need more propellant to accelerate the shell up to speed, so not necessarily a 37% increase in kinetic energy and momentum. Also keep in mind Japanese iron was of lower quality than other naval powers, and the Japanese steelworks industry was incapable of producing steel as high quality as other nations. This would have severely impacted the gun's performance.

[ReefKip]

2 minutes ago, TsAGI said:

If all dimensions are proportional it would be about 37% heavier. But then you would need more propellant to accelerate the shell up to speed, so not necessarily a 37% increase in kinetic energy and momentum. Also keep in mind Japanese iron was of lower quality than other naval powers, and the Japanese steelworks industry was incapable of producing steel as high quality as other nations. This would have severely impacted the gun's performance.

Maybe 20 inch would have a slightly more momentum when plunging fire is used. Seing that it has more weight behind it when coming down.

 But also looking at potential targets to hit in ww2. 18 inch would have done the job nicely enough . 20 inch is just overkill and it faces the issue of overpenning battleships doing less overall damage.But this is something the japs found out themselves because i believe they tested the guns and found the performance not satisfactory if my memory is correct.

To bad yamato never hit anything of worth with her guns IRL. 18inch is a caliber i would have loved reading damage reports about. She near missed an escort  carrier and the splinters and shockwave was enough to damage the engine and electrical equipment onboard.

 

[disc]

The Japanese perspective was that each ship needed to be qualitatively better than its American counterpart, because the IJN would not be able to match the USN in numbers. Battleships were seen as the final arbitrators of sea power, so they would need to outgun the enemy. When designing the Yamato in the 1930s, the Japanese thought a 20in gun would be good because of its immense range, armor penetration, and destructive power. They believed that this would be vital in the theorized big gun Tsushima-type showdown between Japan and the US.

But a gun this size would be very hard to make and might take a long time to appear. It was decided to use 18in instead on the Yamato, as this would still have a big qualitative advantage but would not be as troublesome to build. After the Yamato, proceeding designs would use a 20in gun. This way, if/when the US realized that the IJN had made the jump to 18in guns, any answering US 18in design would be overmatched by yet bigger guns. It was thus planned that the IJN would have a significant gun advantage until about 1950.

[ReefKip]

8 hours ago, disc said:

The Japanese perspective was that each ship needed to be qualitatively better than its American counterpart, because the IJN would not be able to match the USN in numbers. Battleships were seen as the final arbitrators of sea power, so they would need to outgun the enemy. When designing the Yamato in the 1930s, the Japanese thought a 20in gun would be good because of its immense range, armor penetration, and destructive power. They believed that this would be vital in the theorized big gun Tsushima-type showdown between Japan and the US.

But a gun this size would be very hard to make and might take a long time to appear. It was decided to use 18in instead on the Yamato, as this would still have a big qualitative advantage but would not be as troublesome to build. After the Yamato, proceeding designs would use a 20in gun.

9 hours ago, disc said:

This way, if/when the US realized that the IJN had made the jump to 18in guns, any answering US 18in design would be overmatched by yet bigger guns. It was thus planned that the IJN would have a significant gun advantage until about 1950.

 

Another mistake the japanese made is that even if the Americans would have build their own Super BB,s instead of going the carrier route, they still would be able to produce more of them with higher technological advancements compared to the japs. so still this quality above quantity aproach was extremely short sighted. and thus their perspective was flawed from the start. even  from a 1930,s perspective.   but looking at the japanese Plan for the pacific war against the US. it was short sighted overall. The plan was to bait the American Fleet into a decisive battle, which the Japs would win. after which they Hoped the Americans would surrender. this aproach was extremely Naive and optimistic as Japan was in no way capable of preventing the US to wage war by destroying it,s production and Resource Facilities. Which was needed to decisively put the US out of the war,

 

 

9 hours ago, disc said:

This way, if/when the US realized that the IJN had made the jump to 18in guns, any answering US 18in design would be overmatched by yet bigger guns. It was thus planned that the IJN would have a significant gun advantage until about 1950.

except that the American reply would come alot faster then the japanese counter-reply. Japanese industry did roughly 4 years producing the yamato and Musashi i believe? US industry would have those ships ready in atleast half the time. if not even less then that. look at US carrier Production for reference.So japs produce 20 Inch Ship. Americans spot them and have a 22 Inch ship ready in less then 2 Years, which is entirely plausible with all Industry which was focused on carriers now put into Super BB,s.  with which the Americans have  atleast 3-4 years  of Dominance until the Next generation of Japanese 24 Inch gun Battleships  are ready and on it goes like that. it gives no advantage at all to the japs.except at the start of the War in which the Americans have yet to reply to the first Super BB.

For our time line 18 Inch was enough to counter what the Americans put out in the war. 20 inch even if the war went according like Japan had planned,defeating most of The US's Pacific fleet in the first year, would have no advantage.


The  Japanese plan for bigger calibre  for every  new Generation Battleship sounds alot like the German Plan for their Tanks in WW2. in which the plan was to release a new Generation of Tanks every year with heavier armor and firepower. but atleast that made sense as the Germans could guarantee a technological and quality edge over their enemies. unlike Japan which used outdated equipment when Mid-War aproached. combined with a much lesser developed industrial base which did not allow them to keep the edge they had Early war. and you get a japanese dream instead of a plan.

[Shiki]

5 hours ago, ReefKip said:

Another mistake the japanese made is that even if the Americans would have build their own Super BB,s instead of going the carrier route, they still would be able to produce more of them with higher technological advancements compared to the japs. so still this quality above quantity aproach was extremely short sighted. and thus their perspective was flawed from the start. even  from a 1930,s perspective.   but looking at the japanese Plan for the pacific war against the US. it was short sighted overall. The plan was to bait the American Fleet into a decisive battle, which the Japs would win. after which they Hoped the Americans would surrender. this aproach was extremely Naive and optimistic as Japan was in no way capable of preventing the US to wage war by destroying it,s production and Resource Facilities. Which was needed to decisively put the US out of the war,

except that the American reply would come alot faster then the japanese counter-reply. Japanese industry did roughly 4 years producing the yamato and Musashi i believe? US industry would have those ships ready in atleast half the time. if not even less then that. look at US carrier Production for reference.So japs produce 20 Inch Ship. Americans spot them and have a 22 Inch ship ready in less then 2 Years, which is entirely plausible with all Industry which was focused on carriers now put into Super BB,s.  with which the Americans have  atleast 3-4 years  of Dominance until the Next generation of Japanese 24 Inch gun Battleships  are ready and on it goes like that. it gives no advantage at all to the japs.except at the start of the War in which the Americans have yet to reply to the first Super BB.

For our time line 18 Inch was enough to counter what the Americans put out in the war. 20 inch even if the war went according like Japan had planned, defeating most of The US's Pacific fleet in the first year, would have no advantage.

The  Japanese plan for bigger calibre  for every  new Generation Battleship sounds alot like the German Plan for their Tanks in WW2. in which the plan was to release a new Generation of Tanks every year with heavier armor and firepower. but atleast that made sense as the Germans could guarantee a technological and quality edge over their enemies. unlike Japan which used outdated equipment when Mid-War aproached. combined with a much lesser developed industrial base which did not allow them to keep the edge they had Early war. and you get a japanese dream instead of a plan.

You're speaking from the benefit of hindsight, which isn't a good place to start when you're trying to say "from the perspective of the 1930s." In 1936, when the initial requirements for the Yamato class were drafted, the Japanese plan was in no way shortsighted or flawed. The 'decisive combat between surface fleets' was the fundamental doctrine of every major navy going into the late 1930s and early 1940s- and it's worth noting that, had the Americans followed War Plan Orange as they had intended prior to the destruction of their major surface elements at Pearl Harbour, we might well have seen a battleship gun duel in the western Marianas - just as the Japanese had planned for. They were counting on the morale shock of losing the majority of the American fighting fleet and even the temporary inability for the Americans to replace them in order to, if not win a short war, then at least gain a negotiated settlement with terms at least mostly favorable to the Japanese.

You're also seriously overestimating American industrial capacity. Even if we assume that they can build a so-called 'super battleship' in two years or less - which they can't, not then, not now, and not ever - the design and testing process, not to mention the massive lead times necessary to construct 51-56 cm guns and their turrets, would preclude their installation on any such warship. Even if you started in 1939, you would not have those ships ready before 1944-45, as an extraordinarily generous estimate. You'd be better off building larger numbers of modern, fast 406-mm-gun combatants (which is what the USN did, for those very reasons listed among others). One can't look at carrier construction and compare it to battleship construction because battleships require significantly more extra weight that has to be produced with major lead times (armour plate - which even the industrially-giant US had maxed out its capacity for by 1943 - and heavy artillery).

As far as the 'calibre race' of 406-457-506 mm (or 410-460-510 mm if you're Japanese) goes, it's a simple logic of being able to 'outrange the enemy.' If there was a real, serious threat to the American battle fleet from their Japanese counterparts, it was their fighting range. The Japanese extensively drilled to open fire from a longer range than their American counterparts - on the order of 6,000 metres or more. A larger, heavier shell keeps its stability in flight better and retains more kinetic energy on impact, losing less 'punch' over distance. It's a fault, perhaps, that the Japanese didn't develop anything like the 'super heavy' shell, but even then, Japanese shells were generally heavier than their comparable American counterparts until just prior to the war (1,020 kg for Nagato's 41 cm vs. Colorado's original 957 kg for its 16in Mk.1).

Ultimately, the point I'm trying to make is this: it wasn't an unreasonable assumption to continue the pursuit of ever-larger battleships and larger artillery while they continued to be the ultimate arbiters of naval combat. You do not plan to lose a war, you plan to win one.

To quote Bagnasco's The Littorio Class:

• From the doctrinal point of view, battleships continued to be the fundamental and indispensable part of every fleet;
• From the technical standpoint, only a large displacement could offer assurance from threats of guns, torpedoes, and bombs and it would have been a mistake to abandon building battleships as long as other ships with these characteristics existed or could be built, given the uncertain outcome of the conferences on the limitation of naval armaments.

If you want to learn about Japanese naval doctrines and planning prior to the war, I recommend Kaigun. It's an incredibly good English-language source on the subject. If you can read Japanese, I can offer several other titles, but they're a bit pricey (one I would like goes for over $650 USD in its used condition).

Edited October 13, 2020 by Shiki

[ReefKip]

1 hour ago, Shiki said:

You're speaking from the benefit of hindsight, which isn't a good place to start when you're trying to say "from the perspective of the 1930s." In 1936, when the initial requirements for the Yamato class were drafted, the Japanese plan was in no way shortsighted or flawed. The 'decisive combat between surface fleets' was the fundamental doctrine of every major navy going into the late 1930s and early 1940s- and it's worth noting that, had the Americans followed War Plan Orange as they had intended prior to the destruction of their major surface elements at Pearl Harbour, we might well have seen a battleship gun duel in the western Marianas - just as the Japanese had planned for. They were counting on the morale shock of losing the majority of the American fighting fleet and even the temporary inability for the Americans to replace them in order to, if not win a short war, then at least gain a negotiated settlement with terms at least mostly favorable to the Japanese.

You're also seriously overestimating American industrial capacity. Even if we assume that they can build a so-called 'super battleship' in two years or less - which they can't, not then, not now, and not ever - the design and testing process, not to mention the massive lead times necessary to construct 51-56 cm guns and their turrets, would preclude their installation on any such warship. Even if you started in 1939, you would not have those ships ready before 1944-45, as an extraordinarily generous estimate. You'd be better off building larger numbers of modern, fast 406-mm-gun combatants (which is what the USN did, for those very reasons listed among others). One can't look at carrier construction and compare it to battleship construction because battleships require significantly more extra weight that has to be produced with major lead times (armour plate - which even the industrially-giant US had maxed out its capacity for by 1943 - and heavy artillery).

As far as the 'calibre race' of 406-457-506 mm (or 410-460-510 mm if you're Japanese) goes, it's a simple logic of being able to 'outrange the enemy.' If there was a real, serious threat to the American battle fleet from their Japanese counterparts, it was their fighting range. The Japanese extensively drilled to open fire from a longer range than their American counterparts - on the order of 6,000 metres or more. A larger, heavier shell keeps its stability in flight better and retains more kinetic energy on impact, losing less 'punch' over distance. It's a fault, perhaps, that the Japanese didn't develop anything like the 'super heavy' shell, but even then, Japanese shells were generally heavier than their comparable American counterparts until just prior to the war (1,020 kg for Nagato's 41 cm vs. Colorado's original 957 kg for its 16in Mk.1).

Ultimately, the point I'm trying to make is this: it wasn't an unreasonable assumption to continue the pursuit of ever-larger battleships and larger artillery while they continued to be the ultimate arbiters of naval combat. You do not plan to lose a war, you plan to win one.

To quote Bagnasco's The Littorio Class:

• From the doctrinal point of view, battleships continued to be the fundamental and indispensable part of every fleet;
• From the technical standpoint, only a large displacement could offer assurance from threats of guns, torpedoes, and bombs and it would have been a mistake to abandon building battleships as long as other ships with these characteristics existed or could be built, given the uncertain outcome of the conferences on the limitation of naval armaments.

If you want to learn about Japanese naval doctrines and planning prior to the war, I recommend Kaigun. It's an incredibly good English-language source on the subject. If you can read Japanese, I can offer several other titles, but they're a bit pricey (one I would like goes for over $650 USD in its used condition).

I am not speaking from the benefit of Hindsight. i am speaking from Knowing American industrial Might. which was already very well known in the 1930,s are you denying this was known?even yamamoto refered to this i am also speaking from a grand Startegic perspective. while you are speaking from a tactical perspective.  even if everything went according to plan and they could have destroyed most of the american fighting fleet. What could they do with that Short window of naval dominance?

-they could not reach and destroy American industrial centre,s. those were on the mainland for ever outside Japanese reach. a land invasion is out of the question.

-they could not cut off America from any vital resource, because Again. those were on the mainland which caused America to be self sufficient. not depending on trade. which Japan was. so a blockade is out of the question as well,

so what is stopping America to just take those losses. and rebuild their fleet? absolutely nothing. so yes the plan was Short sighted because your dealing with America here. Not Germany for instance. which is a country that relies  on Import of Resources to fight a prolonged war. that is the Mistake you are making.Which japan also made.Counting on the Moral Blow after Pearl Harbour to force the Americans into Submission was not going to happen, unconditional surrender was the focus by then. The entire plan relies on America Wimping out on losses. how is this not Short sighted?

America making Super BB,s in 2 years or less is plausible. The Iowa class battleships were constructed  over 2,5 years as well. and this while America was also focussing their Naval efforts on Building Aircraft Carrier,s at the same time. Now considering we are discussing a situation in which America refrained from Building those carriers and choose to Compete with the japanese on Making Super BB,s. this would have taken them much less amount of time to produce such BB,s. America would both produce them faster and in larger quantities then the Japanese. That picture you have is totally irrelevant to the hypothetical situation we are discussing. because it shows American BB production while being held back by Carrier production. but for something else it is useable. for example it shows Ships like Littorio being produced in a way slower time then Iowa while having less displacement and overall resources needed. Because italy just like japan had a smaller Resource source and industrial base to put into the building of those ships. America did not face this leading them to completing Much heavier designs much quicker then italy completed lighter designs. this can be extended to japan as well.

[madham82]

2 hours ago, Shiki said:

 

As far as the 'calibre race' of 406-457-506 mm (or 410-460-510 mm if you're Japanese) goes, it's a simple logic of being able to 'outrange the enemy.' If there was a real, serious threat to the American battle fleet from their Japanese counterparts, it was their fighting range. The Japanese extensively drilled to open fire from a longer range than their American counterparts - on the order of 6,000 metres or more. A larger, heavier shell keeps its stability in flight better and retains more kinetic energy on impact, losing less 'punch' over distance. It's a fault, perhaps, that the Japanese didn't develop anything like the 'super heavy' shell, but even then, Japanese shells were generally heavier than their comparable American counterparts until just prior to the war (1,020 kg for Nagato's 41 cm vs. Colorado's original 957 kg for its 16in Mk.1).

Very good post, but this part has me intrigued. Just comparing the ranges of the Nagato and North Carolina (which the NC was built in response too), their ranges are very close (40K vs 37K yds). Yamato was more like 45K yrds. Iowa ended up just over 41K. Where exactly did the Japanese envision a range advantage? A couple of thousand yards isn't going to be a qualitative advantage. My guess here is they were thinking the US would not build anything more advanced than the Colorados (which was like 34K) and the like, which IMO is short-sighted thinking. Could be the reality behind their thinking, but I had always heard the idea behind Yamato was to build a ship that could carry the firepower and armor to make up for numerical inferiority, not that range was a real factor. 

Also I find it hard to understand their thinking on range fighting when you have to observe the shell splashes. That means your ability to see the splashes is the deciding factor (i.e. the visible horizon and your own optics), not the range of the guns. Since they did not invest in radar for "blind" firing, or utilize seaplanes for spotting. 

[Shiki]

24 minutes ago, madham82 said:

Very good post, but this part has me intrigued. Just comparing the ranges of the Nagato and North Carolina (which the NC was built in response too), their ranges are very close (40K vs 37K yds). Yamato was more like 45K yrds. Iowa ended up just over 41K. Where exactly did the Japanese envision a range advantage? A couple of thousand yards isn't going to be a qualitative advantage. My guess here is they were thinking the US would not build anything more advanced than the Colorados (which was like 34K) and the like, which IMO is short-sighted thinking. Could be the reality behind their thinking, but I had always heard the idea behind Yamato was to build a ship that could carry the firepower and armor to make up for numerical inferiority, not that range was a real factor. 

Also I find it hard to understand their thinking on range fighting when you have to observe the shell splashes. That means your ability to see the splashes is the deciding factor (i.e. the visible horizon and your own optics), not the range of the guns. Since they did not invest in radar for "blind" firing, or utilize seaplanes for spotting. 

The range advantage they calculated they had was based on the superiority of their optical equipment and the known ranges of the American Standard-type battleships, which they had been able to observe discreetly during the USN's 'Fleet Problems' of the 1930s. Colorado was the basis of their assumptions, since at that time the North Carolina hadn't been constructed yet (and even during the earliest phases of her design process, was slated to receive 356 mm rather than 406 mm). Even if the U.S. decided to construct new 406-mm-armed battleships - which they knew would become a reality as soon as the naval treaties were allowed to lapse without renewal - the range advantage of the Japanese 460 mm over the North Carolina's 406 mm would be enough to ensure at least a temporary superiority. Yamato was, after all, designed not to completely surpass all American future construction - an impossibility, one that the designers were very well aware of - but rather to overwhelm existing older 406-mm-gun battleships. Practically speaking, Yamato is pretty well meant to slug it out with however many Colorados or Nelsons you want to send her way. She's invulnerable to their gunfire at all reasonable ranges (invulnerable to most gunfire period at all reasonable ranges) whilst they simultaneously have no protection against her guns at all.

As far as fighting at range, the practical limit for naval gunnery is 35,000 metres, no matter the era or what kind of optical or radar-directed fire control equipment you happen to be using. The Japanese did not invest extensively into radar until after the Sea Battle off Savo Island, what is known in Western media as the Battle of Cape Esperance (11-12 October 1942), but they did drill with aircraft spotting throughout the 1930s (as did every other major navy). That may have been short-sighted on their part, but like most things, their lack of natural resources (the entire reason they went to war in the first place) and the poor base quality of those that were available precluded their adoption of quite a few advanced technologies.

I have also included a rather decisive comparison of a modern battleship of inferior calibre (often-noted to have guns as powerful as 406 mm) vs. Yamato.

Edited October 13, 2020 by Shiki

[Shiki]

1 hour ago, ReefKip said:

I am not speaking from the benefit of Hindsight. i am speaking from Knowing American industrial Might. which was already very well known in the 1930,s are you denying this was known?even yamamoto refered to this i am also speaking from a grand Startegic perspective. while you are speaking from a tactical perspective.  even if everything went according to plan and they could have destroyed most of the american fighting fleet. What could they do with that Short window of naval dominance?

-they could not reach and destroy American industrial centre,s. those were on the mainland for ever outside Japanese reach. a land invasion is out of the question.

-they could not cut off America from any vital resource, because Again. those were on the mainland which caused America to be self sufficient. not depending on trade. which Japan was. so a blockade is out of the question as well,

so what is stopping America to just take those losses. and rebuild their fleet? absolutely nothing. so yes the plan was Short sighted because your dealing with America here. Not Germany for instance. which is a country that relies  on Import of Resources to fight a prolonged war. that is the Mistake you are making.Which japan also made.Counting on the Moral Blow after Pearl Harbour to force the Americans into Submission was not going to happen, unconditional surrender was the focus by then. The entire plan relies on America Wimping out on losses. how is this not Short sighted?

America making Super BB,s in 2 years or less is plausible. The Iowa class battleships were constructed  over 2,5 years as well. and this while America was also focussing their Naval efforts on Building Aircraft Carrier,s at the same time. Now considering we are discussing a situation in which America refrained from Building those carriers and choose to Compete with the japanese on Making Super BB,s. this would have taken them much less amount of time to produce such BB,s. America would both produce them faster and in larger quantities then the Japanese. That picture you have is totally irrelevant to the hypothetical situation we are discussing. because it shows American BB production while being held back by Carrier production. but for something else it is useable. for example it shows Ships like Littorio being produced in a way slower time then Iowa while having less displacement and overall resources needed. Because italy just like japan had a smaller Resource source and industrial base to put into the building of those ships. America did not face this leading them to completing Much heavier designs much quicker then italy completed lighter designs. this can be extended to japan as well.

I'm not attempting to argue whether or not the Japanese were doomed as a result of their decision to go to war with the United States - that's a subject that's been beaten to death and beyond, right into Asphodel. However, the concept of their plan - which you're saying is short-sighted - is a tactical opinion. Unless you've switched tack from the 'decisive battle' to the overall conduct of the war, grand strategy is not in the purview of the discussion. The entire point is, from a technical and tactical point of view, there's no reason to not go for the larger calibre gun if it's feasible.

As far as American industrial capacity, there is still no method by which the United States can construct a super-battleship in two years or less, especially if it's armed with guns larger than 45.7 cm. The largest calibre that they seriously considered and had actual experience building was 45.7 cm, after all: you can still see the 18in/48 at the Dahlgren Naval Surface Warfare Center in Virginia today. Beyond that calibre - especially jumping to 22in/56 cm - is a completely new field that you have to design, test, and produce an entirely new weapon for. There are basic sketch profiles for twin and triple 457 mm gunhouses, but nothing for anything beyond that, because the USN's surface warfare experts came to the conclusion that - with the known limitations of naval gunnery for the time - that that was the largest calibre you would need.

Going further into this, while one can produce an Essex in around 24 months, one also has to consider that you need so much less to build an Essex than a battleship of comparable displacement. Even the fastest battleship time, Indiana at 29 months, is only possible with the complete mobilization of the American workforce to a war footing - and Indiana is less than half the standard displacement of any potential American super-battleship with guns of that size. Considering that the US had a steel shortage starting in 1943 and had completely maxed out their armour production capacity by that point in time with their construction programmes, it's not unrealistic to say that any super-battleships would have been the first to be axed (the fate of Montana). If anything, the U.S. would have been tapped out for production earlier with anything on that scale - even if you axe the carriers entirely, armour production capacity as well as the speed of creating large-calibre naval guns are a hard cap on how quickly you can produce a battleship. Carriers require significantly less armour than battleships, after all. This goes without going into the other logistical infeasibilities of such ships, like their inability to use the Panama Canal (which would kill them before they made it out of sketch stage), the massive infrastructure overhaul required to transport the materials for their building (their gun turrets would be as heavy as a WWI-era light cruiser), or the requirement to build new slips and dredge anchorages to handle them.

Finally, Littorio and Vittorio Veneto's building times are inflated in that the first pair didn't actually start construction until about 5 months after they were initially laid down. Their actual building times were on the order of 27 and 26 months, respectively - and their displacements were nearly the size of those afforded to Iowa by the time they were finished, despite their nominal '35,560-metric ton' designation.

Basically, this entire conversation boils down to me trying to explain that: "You're right that Japan would lose, but for all the wrong reasons."

Edited October 13, 2020 by Shiki