Ship number 798 - Super Yamato(A-150 battleship)

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Ship number 798
Ship number 798 was to be the most powerful battleship in the world. It was the first Super Yamato-class ship (A-150), but due to the changing war situation, the Japanese abandoned this project. The keel was never laid, but one or two 510mm guns were produced at the Naval Arsenal in Kure to be used by the Super Yamato-class ships.
The Imperial Japanese Navy (IJN), after withdrawing from the Second London Conference in 1936, began designing and building new ships, which according to the Japanese “Doctrine of Decisive Battle” (艦隊決戦). They were to be faster and more heavily armed than the U.S. Navy, which were to destroy America’s main fleet, just as in 1905 the Japanese destroyed the Russian fleet at the Battle of Tsushima.For this purpose, the 4. The Naval Armament Reinforcement Program, which aimed to build 80 new ships for the IJN, including 4 powerful Yamato-class battleships. In 1939, Japanese intelligence reported that the U.S. Navy was planning to build new warships that would be armed with 18-inch guns. The Japanese knew that the American 18-inch guns would be a formidable threat to the Yamato-class ships. It was decided in 1939 that an even more powerful ship than the Yamato was needed. Work on the design of the new battleship began in 1939. To facilitate the design work, the design was based on a Yamato-class ship. The Super Yamato-class ships were to have powerful 510mm guns and a large number of smaller-caliber guns.Plans for the construction of the ships were included in the 5th Naval Armaments Supplement Programme of 1941. Work on 510 mm guns for ships of this class had already begun. The first gun was ready at the end of 1941. Due to the huge weight of the shell (over 2 tons with the propelling charge), work began on a special autoloader and turrets for the Super Yamato.Sources say that the ship could have had two different configurations of size and equipment. All of them are certain that the Super Yamato was supposed to have three double towers equipped with 510mm guns. The design work was completed in early 1941, and the keel for 798 was to be laid in 1942 at the Yokosuka Naval Shipyard. The second ship, number 799, was to be built at the Kure Naval Shipyard.These ships were supposed to be ready in 1946-47, but due to the defeat at Midway, the Japanese Navy needed aircraft carriers and support ships, so plans to build Super Yamato ships were abandoned.At the end of the war, due to the lack of steel, the prototype 510mm guns were melted down to steel mills, and the ship plans were destroyed. From an economic point of view, Japan was neither able to build such powerful ships nor to match the US economy.
Construction description
The standard displacement of the A-150 project battleship with six 510 mm guns was 64,000 tons (according to other sources – 72,000 tons). length of the waterline - 262 meters; maximum width – 38.9 meters, which corresponded to the Yamato-class battleships. The draught at the standard displacement of 10.4 meters also corresponded to the Yamato class. The power plant consisted of 12x boilers and 4x Kanpon turbines with a total output of 150,000 hp. The design speed is 27 knots, fuel capacity 6400 tons, cruise range 7200 miles at a speed of 16 knots.
There is also a theory that Super Yamato was supposed to have 8 510 mm guns and a displacement of about 100,000 tons, but from a realistic and practical point of view, such a ship would be very difficult logistically to build and supply.

Super Yamato art




510mm/45 (20.1") Type 98
Main artillery of ship number 798. Although it is called the Type 98, it is only a guess because the Japanese simply called it A Gun (拳銃) for secrecy. These were enlarged Type 94 guns from the battleship Yamato. A single gun with a breech weighed 223.4 tons. A single turret weighed 2,736 tons, which was only 36 tons more than the turret of the Yamato-class ship. The anti-tank shells for this gun weighed about 2,000 kg, and with a propelling charge 2,500 kg.

  1. Gun characteristics:
  • Gun Weight: 223.4 tons (227 mt) with breech mechanism
  • Gun Length oa: 927.6 in (23.560 m)
  • Bore Length: 900 in (22.840 m)
  • Date Of Design: 1941
  • Rate of fire: 1 - 1,5 - 2 rounds per minute
  1. Ammunition


  • Bursting Charge - 32kg
  • Weight - 1950kg
  • Speed - 780m/s


  • Bursting Charge: 84kg
  • Weight: 1858kg
  • Speed: 805m/s
  1. Mount/Turret Data
  • Weight: 2736t
  • Gun elevations: -5/+45 degrees
  • Elevation rate: 10 degrees per second
  • Train rate: 2,25 degrees per second
510mm/45 (20.1") Type 98

155 mm 15.5 cm/60 (6.1") 3rd Year Type
This gun was to be mounted exactly the same as in the Yamato-class ships.

155 mm 15.5 cm/60 (6.1") 3rd Year Type

Aft_155_mm_gun_turret_Yamato_300px (1)

100 mm 10 cm/65 (3.9") Type 98
They were to be mounted on the sides of the superstructure to strengthen the anti-aircraft defense.

100 mm 10 cm/65 (3.9") Type 98


25 mm/60 (1") Type 96
They were to be the main line of defense against aircraft. Arranged very much like in the battleship Yamato

25 mm/60 (1") Type 96


13,2 mm Type 93
Another anti-aircraft weapon

13,2 mm Type 93


Ship number 798 was to have powerful armor for the spirit of reasons.

  1. To withstand hits from American ships
  2. In order to withstand their own broadside salvos, which were more powerful than those on the battleship Yamato.
  • Engine room
    - Main belt armor (waterline): 410 mm VH
    - Main belt armor (underwater): 200-45 mm NVNC
    - Deck armor (horizontal): 200 mm MNC
    - Deck armor (inclined): 230 mm MNC
    - Bulkhead (bottom): 100-50 mm CNC

  • Ammo stowage
    - Main belt armor (waterline): 410 mm VH
    - Main belt armor (underwater): 200-75 mm NVNC
    - Magazine bottom armor: 80-50 CNC
    - Deck armor (horizontal): 200 mm MNC
    - Deck armor (inclined): 230 mm MNC
    - Side splinter protection: 16 mm DS

  • Main gun
    - Barbette: upper 550 mm VH, lower 490 mm VH
    - Turret front: 660 mm VH
    - Turret side: 250 mm VH
    - Turret back: 190 mm NVNC
    - Turret roof: 270 mm VH

  • Secondary gun
    - Barbette: 25 mm DS + 50 mm CNC
    - Turret: 25 mm HT

  • Main steering room
    - Roof: 200 mm MNC
    - Side: 300-360 mm VC
    - Bottom: 25 mm DS

  • Auxiliary steering room
    - Roof: 200 mm MNC
    - Side: 250 mm VC - 300 mm VH
    - Bottom: 20 mm DS

  • Funnel
    - Uptake: 380 mm MNC
    - Some part of funnel: 50 mm CN

Armor Placement

General characteristics

  • Crew - 3345
  • Standard displacement: 64,000 t
  • Full-load displacement: 72,809 t
  • Max length: 263.40 m
  • Max width: 38.9 m
  • Average draft at trial state: 10.4 m
  • Main boiler: 12x Ro-Go Kampon boiler
  • Main engine: 4x Kampon turbine
  • Power: 153,553 SHP
  • Speed: 27.46 kt
  • Aircrafts: 6 seaplanes


  1. Main Artillery
  • 3х2 - 510mm/45 (20.1") Type 98
  1. Secondary Armament

There are two variants of secondary armament that were supposed to be used on the 798 ship, I will present them below.

  1. First variant
  • 2х3 - 155 mm 15.5 cm/60 (6.1") 3rd Year Type
  • 12x2 - 100 mm 10 cm/65 (3.9") Type 98
  • 52x3 - 25 mm/60 (1") Type 96
  • 2х2 - 13,2 mm Type 93
  1. Second variant
  • 14x2 - 100 mm 10 cm/65 (3.9") Type 98
  • 52x3 - 25 mm/60 (1") Type 96
  • 2х2 - 13,2 mm Type 93
How should ship number 798 be armed?
  • First variant
  • Second variant
  • no
0 voters
  1. Equipment
  • Type 21 air-surface radar
  • Type 22 surface radar
  • Type 13 air radar
  • E27 radio detector

Super Yamato-class ship number 798, if the Japanese had fully completed it, would have been the most powerful battleship in History. In the game, if you were to add it, you would have to do a few things to prevent it from dominating naval battles. My suggestion is:

  1. A maximum of 1 ship per team at a time for Battle
  2. Powerful ships that will keep her in check (Montana-class ships, modernized Iowa, German super battleships, etc.)
  3. introduce it as an event ship and let you play with it by fighting, for example, bots like “Battelship Battel of Earth”
  4. You can also do the same as the Americans with Yamato-class ships, i.e. introduce aircraft strike groups to sink such ships, instead of 1 plane, you can give the player command over the wing of torpedo planes or dive bombers.
    5.Introduce submarines that will hunt battleships (just like the Americans hunted down Japan’s most powerful aircraft carrier)

This ship was, as it turned out later, a blind road in the development of ships, because in the future the most important ships were aircraft carriers, not battleships.I know that a lot of people will be against this proposal, but this ship is a floating monster that even if it cost $250, I would buy it anyway. I encourage you to discuss in the comments and to share your own knowledge on this subject.
Finally, I apologize for the linguistic and logical errors because unfortunately English is not my main language and I had to use google translator.


Design A-150 battleship - Wikipedia
超大和型戦艦 - Wikipedia
Japan 51 cm/45 (20.1") “A” Type 98 (?) - NavWeaps
Super Yamato-class Battleship, No.798 (A-150) - The Strongest Weapon of the Japanese Empire - Japan - War Thunder - Official Forum
Battleships the Size of Supercarriers? Imperial Japan’s Crazy Plan For a ‘Super-Yamato’ | The National Interest
Yamato class genesis – Warship Projects 1900-1950
History of Warfare The Second World War in The East The History of Warfare | PDF | Empire Of Japan | Battle Of Midway (
Battleships Axis and Neutral Battleships in World War II | PDF (
USNI Japanese Cruisers of The Pacific War (1997) | PDF (
Conways All The Worlds Fighting Ships 1922-1946 | PDF (


Given that the bar for construction is far lower in naval (looking at you, Kronshtadt), I see no reason why the A-150-class couldn’t eventually come to the game. I voted for the first configuration, because who wouldn’t want those 155s? I find it really amusing that on top of all of those guns, they still felt the need to put two dual 13.2mm machine guns on it. What are those gonna get that the 156 25mm guns won’t? +1


+1 ^

Would be neat, however it doesn’t even meet the minimum requirement for the game.

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is classified as an unfinished prototype

Because two guns were built? What about the ship for them to go on? There’s nothing to be called a prototype. Also I understand what the suggestion rules are, but iirc naval ship implementation requires for a ships to have been laid down (this means the keel).

The laying of the keel is generally considered the official beginning of a ships construction, for larger ships it’s often an event milestone that’s noted as being equal to the launching/first floating.

Equipment and armament are important, but until there is a hull to put them on they are not considered as a ships fit merely potential.

The lack of detailed plans does not help either. Ships are complicated beasts, more so than many understand, and armoured behemoths are in desperate need of structural and internal layout details to prevent the inevitable bias calls for/against.

The Kronshtadt is often mentioned in such instances, together with the
Z 46/47 etc. But these were layed down, with photos available,. The ‘Super Yamato’ never got this far and simply doesn’t meet the Devs minimum criteria.

Maybe one day such advanced paper projects will arrive as alternatives get thin, but I believe we are still a few years away.

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The laying of the keel is considered enough for a ship suggestion as an partially started ship.

However A-150 fits in our other unfinished vehicle criteria of a unique part of a ship was built. As stated in the suggestion one or two guns were made.

What constitutes an (unfinished) prototype:

  • Vehicle was (partially) constructed
  • Vehicle-specific parts (i.e. guns, powerplants, etc.) were built

Does the vehicle you intend to suggest meet the criteria above? Fantastic! In that case, you have a more obscure vehicle which at least in some capacity existed in the real world and is therefore a valid vehicle to be suggested.

I do not recall any other plans were made for an 51cm gun.
Therefore the A-150 becomes a valid suggestion to be made


Whether or not any guns manufactured remains a moot point as you can’t have vehicle specific parts without a specific vehicle. The design was not finalised and several options remained at the point the project was scrapped.

Its been discussed at length several times. There was a thread just a few months ago that went through the exact same points.

Honestly, Design A-150 would be neat to see in-game so it does have my tentative +1. However, as others have brought up the lack of detailed records on it could indeed be a serious issue in modeling the ship accurately.

Luckily though there was a stop-gap solution considered by the Japanese NGS (which was still squabbling over building an even bigger A-150) where Yamato and Musashi would be re-gunned with the 51cm twins intended for the A-150s. So that might be an alternative solution to the lack of sources for the A-150s

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It’s shooting Armourd personal carriers!!! I need it !!!

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A Moderator already stated that it doesn’t go against their rules. So what you’re saying is redundant. Your arguing that the ship not having a hull shouldn’t be added however going by what the Suggestion moderator said which is the message above yours. States that if even only certain parts of the ship were made this includes just the turrets. Then it is a completely valid suggestion and could be implemented.

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And as I stated although the guns were built there is no finalised design and so cannot count as vehicle specific.

Plus the guns were also considered for refit to Yamato and Musashi so the idea of them being A150 specific also invalidates the condition.

In fact Yamato class refit ships are more valid according to the rules than the “Super Yamato” as both hull and existed, just neither ship survived to see the idea progress.

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These are the moderator’s words. They’re saying it does, you a random with 0 authority on what is and what doesn’t count so you have no say.

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Does the ship itself needing to be laid down still apply? Iirc someone from the development team or one of the community managers said it did (I can’t remember who). There was outrage about the Kronshtadt and someone came out and stated why it was added.

Does this ship only meet the requirements to be suggested rather implemented under current rules, I think this is where people are getting it confused.

(Look up)

I’d rather get clarification, because we’re being told two different things from different entities of Gaijin.

Moderators aren’t God’s, they merely interpret the language of the rules as they see them. Is questioning now forbidden?

If the ship was added it would be necessarily be modelled with purely speculative performance, hull design and armour layout. Even the turret for the gun would have to be a guesstimate based on the 46cm gun equivalent if true figures don’t get dug up. It was obviously based on the A140F6 but wasn’t the same.

The whole result has the potential to be an addition of disastrous proportion. Anything but average in every respect would make the Kronshtadt controversy look boring. Naval is already a mess, this would only make it worse, even more so as the other nations would require counters and that would certainly push the bracket in to paper design territory.

Yamato class genesis – Warship Projects 1900-1950 - the author used original Wartime references and still admits a lot of the A140/150 information is lost and and admits the drawings for the type are ‘speculative’.

It’s not the question of questioning, it’s when you start inserting your own statements and acting like that its fact. However, I am wrong in 1 part. Which is what is defined as incomplete.

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I have been thinking about this one. It fits the rules and your write up is very interesting.

However I don’t think I can support the addition of this one.

Yamato alone would need paper BB’s or almost paper BB’s for many nations such as Montana, Lion 16e-38, Littorio design UP.41 with its’ 16’s, Germany would need H-41 and France doesn’t have an option but should receive the Alsace class. All of that and the only one that is even suggest-able is the Lion because 1 gun was built.

For this ship, particularly with autoloaders there is no counterplay, there is not nerfing it to a manageable level its armour and firepower are too good. Let’s not forget that Yamato was designed to battle several ships at once, limiting her and her successor to 1 per game just puts her onto the playing field she was designed for.

I think that’s all I have to say, it’s already loose on the rules when all other nations are relying on the ‘Paper ships’ mentioned in a devblog long long ago and Japan can already expect the best ship in-game that was actually built.

Still of course a very nice writeup.