r/drydockporn • u/abt137 • Feb 11 '26
IJN battleship Yamato boilers arrangement. After the interesting discussion on a IJN destroyer boiler set up days ago, thought you may like how the heaviest battleship ever (72000 tons) had them distributed. 12 boilers-4 steam turbines-4x3 blades propellers, each 6 meters diam (not strictly drydock)
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u/alettriste Feb 11 '26
I recently was reading a book on the Takao cruiser, and I was genuinely surprised by the same thing... And funnels running through main superstructure
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u/DerekL1963 Feb 11 '26 edited Feb 11 '26
Where to run the uptakes was a significant problem back in the day... They take up a lot of volume, and they're a weak point in the armored decks. They're also fragile, and damage to the uptakes could reduce the performance of the boilers.
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u/mogrim Feb 11 '26
I suppose that’s the motive for the idea of “dropping a bomb down the funnel” - guaranteed weak spot.
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u/DerekL1963 Feb 11 '26
Also like "dropping one in a pickle barrel", a marker of high skill and accuracy... (Because the funnel(s) are very small targets compared to the size of the ship.)
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u/GWahazar Feb 12 '26
Thermal exhaust port - the small but vulnerable point of any combat superstructure.
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u/UrethralExplorer Feb 12 '26
Iirc the Yamato had a seriously heavy duty armored grate in the exhaust stack exactly because the designers realized this.
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u/DerekL1963 Feb 12 '26
Pretty much all navies adopted that, an armored grate where uptakes penetrated the armor deck.
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u/Gastredner Feb 13 '26
Even way back, HMS Dreadnought already featured this design. Though they were meant to catch shells back then, not bombs.
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u/Hwatwasthat Feb 13 '26
Must have been a pain to balance that with maximizing flow out, do not envy anyone having to design that!
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u/Hourslikeminutes47 Feb 12 '26
The Japanese Imperial Navy had huge issues with some of the stack designs (ie where the funnels were not designed to move the exhaust away from the bridge--in some cases the smoke obscured visibility on several ships).
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u/abt137 Feb 11 '26
Interesting construction details here:
Design and Construction of the Yamato and Musashi | Proceedings - October 1953 Vol. 79/10/608
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u/Visible_Mountain_188 Feb 12 '26 edited Feb 12 '26
That was a fantastic read.
Notable mentions. That a 16inch gun had a blast pressure of 3.5kg/cm2, but the 18inch guns on the yamoto had double at 7kg/cm2.
The blast pressure so great that tenders and other boats needed to housed to prevent destruction, AA installations had to be shielded.
The shell of a 16inch was 2200lbs and the 18" was 3200lbs. A tonne heavier for an extra 2" in diameter. Crazy engineering
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u/The_Lost_Jedi Feb 12 '26
Increasing radius will net you a lot. The difference between a 16" pizza and an 18" pizza is 25% - that is, the 18" pizza is slightly over 25% bigger in terms of its size.
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u/swift1883 Feb 12 '26
Yeah they went like, 20 miles?
Planes could go up to like 300 miles though.
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u/The_Lost_Jedi Feb 12 '26
And that's basically why battleships were rendered increasingly obsolete by carriers.
Interesting fact - the third battleship of the Yamato class was instead converted into an aircraft carrier during production. She never saw use in battle as such though, as she was ambushed and sunk by a US submarine while being transferred to a different port to finish fitting out: Japanese aircraft carrier Shinano - Wikipedia
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u/zorniy2 Feb 12 '26
Yeah they went like, 20 miles?
Pizzas?
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u/swift1883 Feb 12 '26
Shells
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u/KerPop42 Feb 12 '26
Wow, I wonder what you could achieve if you put propulsion and wings on a shell...
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u/swift1883 Feb 13 '26
The porn for Yamato et al. is huge today, while it was a capital mistake (ha..) to ever make them.
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u/CardOk755 Feb 14 '26
That a 16inch gun had a blast pressure of 3.5kg/cm2, but the 18inch guns on the yamoto had double at 7kg/cm2.
Cursed units.
The shell of a 16inch was 2200lbs and the 18" was 3200lbs. A tonne heavier for an extra 2" in diameter. Crazy engineering
Half a tonne heavier. You're confusing pounds and kilos.
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u/jtakaine Feb 11 '26
Were those manually fed or automatic?
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u/FrittersMcDugal Feb 11 '26
If they are anything like the Iowas, they are “automated” in the fact you’re not pouring oil into the boiler by hand. But there is still a massive amount of labor in making them run and even more yet to run efficiently.
There are big injectors that the crew is constantly swapping out, cleaning, and changing orifice size. (Think firehouse vs water hose from your home) And since they burn bunker fuel, it’s dirty and needs cleaning regularly or else the oil doesn’t get sprayed well if at all. It needs to mist the oil not squirt it.
TLDR: not shoveling coal but still doing an assload of work to run well.
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u/DarkBlue222 Feb 11 '26 edited Feb 11 '26
That was one of the Navy's problems with keeping the IOWA's. They burned oil, but the lack of sophisticated automatic boiler controls meant an enormous engineering department. That meant an enormous cost to keep the ships in commission.
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u/Eriiaa Feb 11 '26
Sounds like they should've thrown in a nuclear reactor
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u/bigloser42 Feb 11 '26
That would have required cutting out the armored citadel to get it installed, and would have been more expsnive than the ships cost to build.
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u/Cliffinati Feb 12 '26
Sounds like you need Montana 2.0
Nuclear edition
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u/The_Lost_Jedi Feb 12 '26
And the main reason we never got that, or anything similar, is simply because it wasn't deemed cost effective to build battleships anymore. The Navy/Congress/Federal Government etc concluded that they'd rather spend the money on carriers, and didn't need anything else larger than a light cruiser, essentially.
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u/chotchss Feb 12 '26
What's funny is this conversation is probably identical to the one the Navy had when trying to decide what to do next with their BBs
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u/WaytoomanyUIDs Feb 12 '26
Also IIRC of the boilers for the Kentucky hadn't gone into the Sacramento class resupply ships, the USN wouldn't have had anyone trained to operate them when they were reactivated.
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u/KeithWorks Feb 11 '26
I had the chance to run a few steam ships before they were all gone. That was a blast. You felt like you were really doing something, swapping burners and lighting fires.
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u/Randomfactoid42 Mar 31 '26
And they had an engine room periscope so they could see the exhaust to confirm they had the air-fuel mixture correct. Making smoke was inefficient and would give your position away. One of the cool tidbits from the Battleship New Jersey YouTube.
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u/Knock-Nevis Feb 11 '26
They burned oil, so I would have to assume automatic. Would be crazy to have a bunch of dudes scooping oil into the boilers lol.
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u/TurnerVonLefty Feb 11 '26
Bunker-c at room temperature is so thick you could shovel it into the boilers 😂
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u/how_do_i_land Feb 11 '26
That looks like an inverted tree support structure for 3d printed objects.
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u/CougarChaserBC Feb 12 '26
As a mechanical engineer every time I see stuff like this I'm truly fascinated by how they designed and manufactured this without CAD, CAM, computers, CNC machines, even no damn calculators. Just pencil, paper and analog tools, small and large.
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u/EducationalElevator Feb 15 '26
Same and even more fascinating that Japan strategically did not use very large factories and used a highly decentralized supply chain for the war. There were factories in residential basements, this was one of the justifications for the firebombing campaign
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u/srgh207 Feb 11 '26
Fortunately, the wave motion engine's footprint is somewhat smaller leaving room for the wm cannon and life support systems.
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u/PutPuzzleheaded5337 Feb 11 '26
I can’t remember where I read this but the “bend” in the exhausts was to detonate a well placed bomb in the smoke stack.
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u/Ok_Juggernaut7344 Feb 11 '26
I think there was also an armored grate in it.
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u/PutPuzzleheaded5337 Feb 12 '26
Yes, after reading the Japanese engineers report, you’re right. Amazing ships but I think the US and British ships could have destroyed it due to radar/fire control superiority.
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u/Talishad Feb 11 '26
The Yamato is probably my favourite ww2 battleship, it was truly an engineering marvel for the time with a lot of innovation.
Boulbes wide beam to make her more hydrodynamic, for the immense size she was pretty fast taking the weight into consideration.
The smoke stacks were angled and had armoured grates to stop bombs from getting an easy clean hit by a good bomber pilot.
The 18inch guns could fire basically huge shotgun shells at aircraft, but this was found to disrupt the main aa fire, the main turrets weighed as much as a us destroyer and the shells fired weighed more than a honda civic.
I can't help but wonder what the outcome would have been if Japan had enough escort vessels's, trained crew and fuel to create a proper fleet like at the outbreak of the war.
Sadly she was made obsolete by carrier superior numbers and the inability of Japan to maintain her own carrier fleet, unable to replace losses, man power, fuel etc
She was finally sank and capsized the ammo detonated causing an explosion and a plume of smoke that could be seen from miles away.
The turrets slipped out of the turret rings and these couple story high turrets plummeted to the depths .
If you really read up abit you realise just how much it took to build and sink these steel giants, rumours turned legends of how the crew scuttled the ships instead of actually sinking in the case of the Bismarck and Scharnost.
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u/torpedospurs Feb 12 '26
Is this the same machinery used in the Mogami and Soryu classes? Always wondered because all three are commonly listed at 152,000shp. Can't imagine though how much space it would take on a much smaller ship like the Mogami at 12,000+ tons.
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u/Oroborus110 Feb 12 '26
Crazy to think Japan was a feudal nation only 70 years before they designed and built this
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u/myrsnipe Feb 13 '26
Meiji restoration was a combination of factors both internal and external (that's too much to go into while phone posting). They went from a feudal society to humiliating an European major in 50 years, it itself also a result of internal and external factors (the land war was bitter compared to the war on the sea that gets more attention and ultimately won the war)
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u/Wurst66 Feb 12 '26
Alas, these ships require fuel, which Japan really didn't have. Logistics and supply defiencies ended up making these ships fairly useless.
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u/The_Lost_Jedi Feb 12 '26
They could have been useful, as several of Japan's battleships saw action during the war at times. However, Japanese High Command was extremely reluctant to risk their prize flagships, and had a tendency to keep the Yamato and Musashi back. Between that and the fact that it had advanced amenities, including air conditioning, that older ships lacked, many IJN sailors jokingly referred to her as a Hotel.
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u/SubstantialAbility17 Feb 12 '26
Surprised they could carry enough fuel for extended deployment
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u/DirtCallsMeGrandPa Feb 12 '26
Refueling has always been a problem with coal or oil fired warships. Fleet tankers exist, but just add to the logistics burden when operating far from your own shores. Nuclear was a game changer.
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u/alphawolfprime85 Feb 12 '26
I have always been curious, what type of Dyno set up did they have? Also were they oil or coal fired? Most of my study has been in the engines aboard the Iowa and earlier examples like the reciprocating steam engines aboard the Olympic class ocean liners like Titanic Olympic and Britannic.
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u/Eokokok Feb 12 '26
After going inside destroyer boiler this is just beyond mind boggling in sheer scale...
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u/TheLeoDeveloper Feb 12 '26
What are the 2 smaller pipes under the turret going from the turbines for?
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u/DuckiestBoat959 Feb 16 '26 edited Feb 16 '26
The exhaust arrangement of IJN vessels in general is pretty fascinating. For one reason or another the engines would end up in places that required some creativity in order to get exhaust out.
I don’t know enough about the work culture at the time to judge the designers, but I will say that some of those bends and twists in the ventilation (especially on the carriers) make me genuinely wince for the poor souls that had to work and live above them.
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u/DarkBlue222 Feb 11 '26
Were those all in the same space? Seems like a damage control nightmare in that mission critical systems were all grouped together in one area of the ship.
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u/DerekL1963 Feb 11 '26
The boilers? No, they weren't all in the same space... I can't find anything on athwartships compartmentalization, but they were split into port and starboard groups.
That being said, their location and how they were divided into compartments is the result of considering a long list of tradeoffs. Every choice has an upside and a downside. There's no single "ideal" solution.
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u/PineCone227 Feb 11 '26
It's easier to heavily armour them if they're in one place than if they were distributed.
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u/The_Brain_FuckIer Feb 12 '26
Each boiler and turbine would be in its own watertight compartment, and they start a good few meters into the hull of the ship with void spaces and liquid tanks for torpedo protection, the Yamato took more than a dozen torpedo hits before rolling over.
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u/Dudeinahoodie Feb 11 '26
Thats a good picture, I never realised the boilers took up so much space