IJN Hiyo - Guide 334

The Hiyo class, converted aircraft carriers of the Imperial Japanese Navy, are today's subject.
Read more about the the ships here:
The Japanese Aircraft Carriers Junyo and Hiyo - Warship IX
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[@Drachinifel]

Pinned post for Q&A :)

[@potatomasher1852]

Had the Japanese Navy's 1920s Number 13 Battleship program been actually implemented, how would other WNT members react? Do you think Japan would see a need for a ship like the Yamato-class in the 1930s and how effective would they be in WW2? Finally, what do you think a No. 13 battleship refit look like?

[@AdelineLowry]

You've often mentioned that converted carriers were far less efficient than purposefully designed carriers. Considering the Hiyos were purposefully designed to be converted, how efficient were they compared to other carriers?

[@michaelkovacic2608]

How large was the speed difference of a typical WW2 battleship with a full fuel load vs with almost empty tanks? For example, the Bismarck-class could store over 7000 tons of fuel oil, therefore I would expect quite a bit of speed difference. Furthermore, could this explain why Bismarck didn't refuel in Norway before heading out into the Atlantic? Since Prinz Eugen would have to refuel earlier anyway, it may have seemed like a good idea to go to sea without full tanks in exchange for perhaps an extra knot of speed for the dash through the Denmark Strait.

[@airplanemaster1]

Do you see torpedo boats?

[@m8rshall]

Drach - What did you do for the Kings Coronation? Only asking as this video was posted on the day!

[@VosperCDN]

Pretty metal of the DD captain to put his ship in the way of those torpedoes. Took his oath to protect the carrier to the limit.

[@jamesm3471]

I’m gonna guess that 100/100 Japanese DD captains would rather take a couple enemy torpedoes for their carrier, even if it costs them their tin can and the their life, than have to sink it themselves with their own torpedoes, after watching it burn for hours first. You’re still right about it being bad•ss though.

[@fearthehoneybadger]

When two torpedoes were heading towards the Taiho, a pilot that had just taken off saw them and crashed his plane into one. The other torpedoe struck home and, due to poor design and damage control, the carrier still sunk.

[@bkjeong4302]

@@fearthehoneybadger More the DamCon than the design, to be honest. Taiho could have been saved if not for the idiotic decision to try to vent the avgas fumes by sending it throughout the entire ship, causing her to basically fart herself to death.

[@thewick-j1837]

​@@bkjeong4302 poor training and an early doctrine for damage control definitely played a huge part but a poor ventilation system and a severe sensitivity to shock made the carrier extremely vulnerable even with a well trained damage control team.

[@fearthehoneybadger]

@@bkjeong4302 A combination of the two. The ship's design included such errors as a sealed hangar deck and a deeper than normal elevator well. When a fuel line was severed by the torpedoe, fuel built up in the well and, when the damage control officer foolishly activated the ventilators and circulated the fumes around the ship, the hanger, full of fumes due to it having no ventilation from outside, exploded, sending flames around the ship to cause additional explosions. Yes, the damage control chief screwed up, but, it was the ship's design that made it far more vulnerable to his goof.

[@mattblom3990]

The highlighting of the the 5" guns on the blueprints is a cool effect. I've noticed you use that at least once before recently. It's a nice quality of life addition to the channel.

[@erikth1986]

It is often difficult to see small details on a ship in a black and white possibly censored picture of a moving ship taken from a moving ship. This is a great addition indeed.

[@Drachinifel]

I'm going to try and incorporate it into more videos going forward.

[@Alighierian]

@@Drachinifel It is indeed pretty nice. As for specific feedback: It might be worthwhile to experiment a bit more with opacity for the mask, and the gradient size around the POI's. I feel the effect could use a bit more contrast, especially when highlighting the smaller items.

[@BleedingUranium]

@@Drachinifel Yes please! It's often quite a task to track down the specific placement of all the armament on a given ship, especially smaller stuff like light AA, and especially especially if you're not already familiar with the ship. Basically any online written source tends to just state that they were present without specifics, most photos often aren't great for finding details like every last Oerlikon, and while video game models (game-dependant) and model kits tend to be fairly good, they aren't always 100%.

[@jasonkrantz3643]

@@Alighierian seconded!

[@SoloRenegade]

the fact an unarmored carrier is one that actually survived the war.....

[@jamesm3471]

Her skipper must have read about the previous World War’s Battle of Jutland, made a trip down to New Zealand before hostilities, and stocked up on Māori warrior garb to wear into battle!

[@kristianfischer9814]

Not for lack of trying on the part of the USN.

[@jamesm3471]

They sank damn near everything they saw that was still floating, eventually.

[@alexzenz760]

Armor is overrated....

[@VersusARCH]

Few carriers were armored.

[@sse_weston4138]

YES I HAVE BEEN WAITING THIS GUIDE FOREVER! It is also interesting to note that Izumo and Kashiwara Marus were not the first of NYK to be subsidized with plans to convert them into aircraft carriers. The sisterships Asama and Tatsuta Marus (and later half sister Chichibu Maru) were meant for conversion into aircraft carriers. It was only until NYK had the two newer hulls that would become Hiyo and Junyo that the Imperial Navy passed up the older liners. Instead Asama, Tatuta (exTatsuta) and Kamakura (ex Chichibu) Marus would all be sunk as troopships; each with heavy loss of life might I add.

[@tonymanero5544]

Learn from Ryan Shymanski of USS New Jersey that the SS United States, around 1950, with something like 200,000 shp, was subsidized to have warship like build as a potential troop carrier.

[@grondhero]

7:08 I was multitasking and at first I thought those subs were torpedo blisters on the carrier.

[@ph89787]

One thing you left out Drach was that Jun'yo was in the background during the Naval Battle of Guadalcanal. As her Zeroes first provided CAP for the damaged Hiei and the Convoy that steamed down the slot on 14 November. Of course that didn't work out when aircraft from Henderson Field and Enterprise showed up. Supposedly, one of Jun'yo's Kates had found Enterprise but by the time she launched a strike Enterprise moved on.

[@Drachinifel]

The episode was already well over time 😀

[@Aelxi]

@@Drachinifel **also laughs in 10min guides** Made another episode for Junyo then!!

[@mbryson2899]

He's got a lot of folks such as yourself to help, an aspect of this channel I very much appreciate.. 😁

[@blakek4750]

My grandfather (97, still with us) snuck about Junyo when it was in port due to be scrapped. Still has photos that his buddy took of him posing on the flight deck.

[@MangoTroubles-007]

He didn't have to sneak aboard her, US Navy officials boarded her and accessed she was a total loss and scrapped her. People like you who lie for attention need their accounts removed.

[@blakek4750]

@@MangoTroubles-007 high IQ reply here bud. If you take issue with my use of the word "snuck", perhaps consider that my grandfather was a Marine Corps radio operator and therefore had no reason to be onboard Junyo. The photos suggest Junyo was a restricted area at the time. You or I weren't there in 1945 but my grandfather certainly was. I'm no liar. Try again.

[@ph89787]

6:56 The bomb hits to Hiyo were from Enterprise’s VB-10 and the torpedo was from Belleau Wood’s VT-24. Jun’yo’s hits were a bit more complicated as Enterprise’s VB-10 and Lexington’s VB-16 claimed the credit.

[@jamesm3471]

“Not Enterprise again! I’m so sick of those guys!” -Every IJN Admiral in WW2

[@Raptor747]

Enterprise: "I will not suffer an enemy carrier to live." It's kind of funny how Enterprise and Saratoga must have felt like ancient relics by the late-war period that somehow were still on the front lines and kicking ass.

[@yoseipilot]

@@jamesm3471 They could have done better to sink her easy

[@ph89787]

@@Raptor747 by the end of the war. Saratoga was reassigned as a training carrier. But Enterprise was supposed to have returned to the frontlines and had the Japanese not surrendered. She would have participated in Operation Downfall.

[@baconpwn]

​@@ph89787 "And this is how you catch a torpedo." - Saratoga, teaching the next generation

[@Emperorvalse]

One of my favorites. For some reason I love the small Japanese carriers, they were not that effective but these two kept fighting with all their tiny might.

[@Heike--]

Any time a Japanese light carrier shows up in a battle you know it will be sunk in short order. If it lives, it had engine trouble and didn't contribute to the battle.

[@hanzzel6086]

​@@Heike-- Aye, but that didn't stop them trying! Although it really should have....

[@zeedub8560]

Even Hosho. She was with the Main Force at Midway with a few obsolete planes, but suddenly she was the only operational carrier in the area and launched her planes as scouts. One of her planes photographed the burning Hiryu.

[@EliteF22]

Love their experimental island design which became the basis for Taiho and Shinano's islands.

[@gregorywright4918]

It makes sense given their cruise liner origins, although it broke with IJN tradition to try to vent below the flight deck off to the sides. Most of the other nation's carriers brought the smoke up through the island, though the angling was cute.

[@malakaman9468]

The most beautiful carrier class, for sure. That trunked funnel is so graceful...

[@GrahamWKidd]

30 minutes and 2,000 views. So whose been sitting home on a Saturday waiting for the latest Drach 5 minute guide then?

[@yes_head]

I'm always amazed to learn about a Japanese capital ship that actually survived WWII.

[@Ragefps]

There were actually a surprising amount sitting around the home islands at the end.

[@jamesbird6140]

Have you ever done videos on important military ports. Sasebo is a fascinating place. I lived there for 5 years. From what I was told it was just a fishing village until the IJN took an interest in this amazing natural harbor. The giant dry dock that is now the core of the US morning basin was also interesting

[@matthewfinkenbinder5846]

Great as usual. A recommendation on the note of interesting converted carriers: U.S.S. Wolverine and U.S.S. Sable. America's coal fired, hangerless, armor less, SIDE PADDLE WHEEL aircraft carriers. They might not have seen action but nonetheless played a vital role and were unique in naval history. Also of note is the Wolverine (then Seeandbee) was the largest built passenger steam paddlewheeler on the lakes (maybe ever?) so was remarkable even before her conversion.

[@gregorywright4918]

You can do that when you know they will only steam on land-locked lakes where the most dangerous antagonist might be a drunk Canadian moose.

[@matthewfinkenbinder5846]

@@gregorywright4918 won't argue that. Anywhere else it would be impractical but they were none the less important. Wasting a true carrier for landing and takeoff qualifying which would have to be done where they'd risk sub attack or mines is risky and ties up a useful CV. These two provided a cheap, safe alternative that didn't tie up a combat useful ship. Something like 1600 pilots qualified on them. That's a hell of a return on investment.

[@Rocketsong]

@@gregorywright4918 Well, the most dangerous adversary is clearly a newly minted ensign learning to land. ;-)

[@USAAmutual45]

@@gregorywright4918 A moose bit my sister...

[@jwenting]

@@Rocketsong and the notorious Great Lakes weather.

[@ThanatosZine]

The highlighting of gun positions on line drawings while you're talking about them is a great addition. Those things can be hard to locate when you only have a few seconds.

[@roho10011]

I’ve always had a soft spot for this class; they were handsome ships (if not the most effective). Thanks for the content!

[@jamesm3471]

I was always surprised the Hiyō Maru and Jun’yō Maru survived the war as long as they did. It’s not like they were of Shōkaku and Zuikaku quality.

[@1pierosangiorgio]

yep. US aviators and submarine commanders would target the better targets first + luck!

[@jamesm3471]

@@1pierosangiorgio Tell that to the IJN Shōhō! First real day on the job, and the poor girl, a _Light_ Carrier, gets hit with more ordinance in ten minutes than most of Pearl took in 2 hours!

[@1pierosangiorgio]

@@jamesm3471 true! that ship should be made into a honorary member of the 1905 Russian baltic fleet.

[@yoseipilot]

@@1pierosangiorgio It’s depend what they spotted first

[@jamesm3471]

@@1pierosangiorgio Haha! I’d be outraged if it didn’t!

[@BleedingUranium]

Yay another Japanese guide! Hiyou and Junyou always seemed interesting, but I didn't know much about them specifically; the angled funnel through the island is super cool. And I'm really loving this new practice of highlighting armament locations on the plans, it's immensely helpful for stuff like smaller-calibre AA placement. Most places, even rather technical ones, tend to gloss over actual placement, leaving one to try to figure it out by squinting at grainy photos or comparing various video game models and/or model kits to see which of them seems most correct.

[@-Castial-]

Really loved the way you present the ships in your newer videos

[@dennisharrington6055]

Thanks. I really like your work. Museum ships all over the US, but it’s a tough gig, Mother Nature has ALL the time in the world, and don’t need money.

[@mikejames4648]

As always Drach, informative and enjoyable, with just a touch of dry wit.

[@mbryson2899]

_USS Trigger_ also torpedoed _Hiyo._ They thought they'd scored four hits but two turned out to be prematures. Thanks for another excellent "Five" Minute Guide, Uncle Drach. 👍

[@theblackbear211]

Another fine job. Thanks.

[@schlirf]

To quote my favorite game, Complete Carriers At War: "Hi Yo, Hiho!"

[@jamesfee1966]

The merchant ship at 1:57 with 10 x quad torpedo launchers!!!

[@craigyork-lz5us]

The sub at 7:26 looks to be one of the Ha-201 class of small coastal submarines that almost made it into service late in the war. They were most comparable to the German Type XXIII U-boats, with streamlined hulls intended for high underwater speed.

[@Ralph-yn3gr]

I've always liked these ships. Not entirely sure why. Just have a soft spot for them. I wish we'd taken Jun'yo as a war prize and rebuilt her into a museum. We could have parked her in Pearl Harbor to really dive into the Japanese side of things.

[@ph89787]

I refuse to live in a world where a Japanese carrier is preserved and not Enterprise.

[@panzerschliffehohenzollern4863]

​​@@ph89787 Damm shame what they did to CV-6.

[@Ralph-yn3gr]

@@ph89787 They should have preserved her as well. I never said they were mutually exclusive.

[@bkjeong4302]

@@ph89787 I had this very implausible but hilarious idea of an alternate history scenario where, because Halsey ignores the Japanese bait at Leyte Gulf, Zuikaku ends up surviving the war in a badly battered state. The Americans want to use her as a nuclear test target, but Chang Kai-Shek says no and takes her as a war prize. Then she gets captured by the communists during the Chinese Civil War and gets refitted for handling jets and an angled deck. Later on, the Indians buy Enterprise off of the Americans instead of a British carrier and refit her to handle jets and an angled deck. Then one of the various conflicts between China and India erupts into full-blown war. And then we get Enterprise vs Zuikaku: Round 5, Jet Age edition and with nukes.

[@GearGuardianGaming]

​​@@Ralph-yn3gr idk if its true or not, but according to wikipedia, USA did take junyo as a war prize. But they also found it to be beyond repair and sold it for scrap in japan. Edit for spelling...stupid fat thumbs.

[@Eulemunin]

Lovely ships in both forms.

[@ronalddevine9587]

It would be interesting to see a video on the current Japanese Navy, or Maritime Force as I believe it is called. They were a formidable power.

[@keefymckeefface8330]

Drach simply doesn't do modern stuff- too much is classified to be able to get full picture.

[@LuqmanHM]

Last time i am this early, Japanese ww2 aircraft carriers was still a thing to be worry about

[@Masada1911]

Today Japanese aircraft carriers are something to get excited about

[@LuqmanHM]

​@@Masada1911 for sure with those F35s😊

[@jamesm3471]

Yeah before piss poor damage control and the Japanese Navy’s own Long Lance torpedoes sank them all…

[@CAP198462]

@@Masada1911 that is not an aircraft carrier, it’s an mobile emergency landing field.

[@adrianjorgensen3750]

I’ve actually been to Kashiwa in Nara prefecture. It’s famous for an amazing shrine.

[@VintageCarHistory]

Hi! Yo! A ship named by putting two greetings together.

[@comentedonakeyboard]

You're welcome😂

[@christophercripps7639]

For a warship built to beefed up mercantile standards, Jinyo sure survived more hits than presumed purpose built warships. Very telling about IJ near the end- need to use an aircraft carrier as a merchant ship: merchant fleet devastared + no carrier capable pilots & av gas.

[@gregorywright4918]

She was often delivering aircraft to southern bases, and she still had the speed to evade most subs, though breakdowns would plague her and lead to more hits.

[@Heike--]

Something never talked about was how hard it was for the Japanese to get replacement aircraft from the factories in Japan to the front lines in the Pacific. Tons and tons of aircraft crashed during the flight out, or got lost and ran out of fuel over the ocean. It was a significant number, and got worse as the war went on due to loss of pilot expertise.

[@Ryvaken]

This is less the history of a warship and more a story of well-deserved sadness and regret.

[@korbell1089]

I am 62 years old and today I learned that there was a ship called the HMS Unicorn! My granddaughters love unicorns.😅😅 And to think that for years I thought the best British name for a ship was HMS Buttercup, how naive I was!

[@airplanemaster1]

For other cute names, you can never go wrong with the Flower class corvettes. And the fact there could have been an HMS Pansy

[@m8rshall]

There's at least 2 - Drach did a video on the other Ship of the line HMS Unicorn that is still around and that you can visit!

[@Nexusgamer8472]

We only name ships/subs HMS Unicorn because it's the national animal of Scotland (i'm not making this up this is an actual fact, although given that the national animal of Wales is a Dragon makes it more believable)

[@MrWhy6]

I love british ship names. My favorite is indefatigable no matter what they say they made that word up.

[@benwilson6145]

the almost 200 year old HMS Unicorn is still afloat and berthed in Dundee

[@erikvandootingh7402]

Thr number of torpedo strikes these ships survived really shows how much simple size matters, when we give so much attention to armor and torpedo defense systems.

[@bkjeong4302]

Yamato is another case study in this-her TDS was one of the few legitimate design flaws with her, and a big one at that (it was the fatal weakness to an otherwise excellent protection scheme), but her sheer size meant she still took 9 torpedo hits all to one side to actually be mortally wounded and even then went down slowly enough that the USN sped up the process with three more torpedoes.

[@matthewrobinson4323]

Excellent video, as always. Informative and entertaining.

[@michaelsnyder3871]

The following is mostly based on the article in Warship magazine by Hans Lengerer and Tomoko Rehm-Takahara but Conway's, Chesneau, Watts, Stille, Brown, Jenshura, Jung & Mickel, Dunnigen & Nofi, Beerbaum, et al, were reviewed. These two ships had just been laid down as large, fast (24 knot) passenger liners. They were subsidized by the government to include features that would allow them to be quickly converted to carriers. A major limitation on air group was the height of the hangers, the lower hanger having barely ten feet of height, preventing the folding and unfolding of the wings of the B5N and B6N. In addition, the conditions in the lower hanger were very bad, especially as far as ventilation. In this case, however, the extent of the conversion caused the construction to take longer, especially with decision to replace the high temperature, high pressure commercial boilers with standard Navy boilers, resulting in mismatched machinery that never performed as well as expected despite excellent trials results. This class introduced the first integrated island/stack on a Japanese carrier. Despite this immense effort, the end result was a 25 knot “Hiryu” without the armor or anti-torpedo protection at nearly the cost in steel of a “Shokaku” class carrier. Note. References differ as to whether all the machinery or just the boilers were replaced or even if the machinery was replaced at all. The commercial boilers were a new, almost experimental (for the Japanese commercial shipbuilding industry) high temperature, high pressure type, with supporting accessories not normally seen in Japanese naval or commercial boilers. The turbines were designed to match the performance of the boilers. The IJN engineering staff assigned to the ship, even if former mercantile personnel mobilized to active duty, would have been unfamiliar with the operation and maintenance of such a plant. Some references state that the ships were only good for 22.5 knots “sea speed”, this despite Navy trials at expected operational displacements which produced speeds in excess of 25 knots. The lower “sea speed” could have been the result of operating the ships at higher displacements than planned, with a result typical for all warships. The USS Wasp, a similar sized warship, made 29 knots at trials displacement, which meant she was good for about 28 knots at battle displacement and but could drop to as low as 26 knots at emergency load displacement. Another possibility was that the ships retained their commercial boilers, and that the boilers were operated at full load during trials with the builder’s staff present and available to assist, but the ships’ engineering staff preferred under service conditions to operate the unfamiliar boilers at lower temperatures and pressures as a safety measure and to reduce the maintenance demands. Add that situation to operating at full load, rather than expected battle loads, and time out of drydock in tropical waters, then a 25 knot ship becomes good for only 22.5 knots. Historically, the hulls were requisitioned by the IJN in 1940 after the keels had been laid. Interestingly, these ships are a parallel example of the extensive type of conversions the USN intended in its XCV program from 1922 to 1941 for ships such as the SS Leviathan, SS Washington and SS President Coolidge among others.

[@gregorywright4918]

There's a reference in one or two works to them being based on the SS Bremen, just scaled down, but that could explain the high-pressure boilers. Most works I've seen say they were replaced with Kampon boilers, the standard IJN set. Would be interesting to see design sheets for the original cruise liners. Laid down 30 Nov. 1939, sold to IJN while building 10 Feb. 1941, launched 24 June 1941, commissioned 31 July 1942. The time from sale to launch was only 4 months, so they were probably not converted very much before launch, just finished for hitting the water, but that is usually when the boilers and engines are sealed in. Might be enough time to upgrade the boilers. That would make some sense as it would mean the boiler staff would be familiar with Kampons. The longer time from launch to commissioning would be the changes to rip out the cruise liner fittings and install hangar deck, flight deck, island and gun sponsons. Of the XCV you listed, the Leviathan had the same speed but was much bigger (and German-built, with higher-pressure boilers), while the other two were similar sized but only about 20 knots.

[@michaelsnyder3871]

@@gregorywright4918 The USN XCV program was mostly intended to get auxiliary carriers into service to serve the Battle Line with air defense, scouting, ASW and observation. Since the USN Battle Line at emergency full displacement was at best 18 knots (thanks to USS Oklahoma), 20kt carriers would be fine. This would release the fleet carriers to seek out the enemy forces, destroy their carriers, reduce the island air bases and establish air supremacy over the battle area. From 1919, the USN knew from gaming that hundreds of aircraft would be needed with the Fleet, along with at least a 100% reserve to counter attrition. The first working powder catapult entered service in 1926, while flying off platforms were ineffective from 1922 on. That meant Fleet aviation would depend on flight decks, captured island bases and flying boats with their tenders. SS Leviathan went to the breakers in 1938. She had been launched back in 1914 and was coal fueled until no earlier than 1922 or later than 1932 when her boilers were converted to oil. Still she would have featured a flight deck over 900 feet in length. She could have operated F5Fs, A-20s and B-25s. But again, most of the primary sources were burned by the Navy Ministry staff and so we will probably never know the whole story. Still, the IJN put destroyer plants in auxiliaries converted to light carriers.

[@mikhailiagacesa3406]

CVLs kickin' it.

[@olivermcgimpsey841]

Loving this channel 😊

[@jamessearcy7079]

One comment I'd like to make about the torpedo bombers for fighters trade mentioned in the Hiyo's aircraft complements: though I've never seen it stated explicitly, I suspect it's because they couldn't operate B5N2s except in favorable wind conditions. Parshall and Tully mention that Kaga had difficulty operating her B5N2s in unfavorable wind conditions because they could not take off without 30+ knot wind speed over the flight deck and Kaga could only make 28. Hiyo and Junyo had shorter decks and slower speeds than Kaga did, so it follows that they would have great difficulty launching an armed Kate without at least a ten or fifteen knot wind.

[@laytonlacorte8107]

It wouldn't be a Drach video about a WWII IJN vessel without him talking shit about the Japanese AA guns.

[@bkjeong4302]

Or specifically the Japanese 25mm.

[@kittyo9633]

Thank you sir

[@水雲-e6k]

The novelty of these aircraft carriers is that it can pass through costs and international treaty loopholes It is important to create alliances with former enemies, to increase common values and perceptions, and to share war lessons to face new challenges and shape the future

[@vincentcondron588]

Very nice video about this conversion of this ship but this has just gave me the idea of the MAC conversions for the royal navy could you do a video for us

[@happysadsmile7628]

This I interesting, also I have a suggestion for a ship from the Royal Thai navy, the Thonburi class, HTMS Sri Ayudhya.

[@paigehamilton4772]

Wow, she took one hell of a beating and made it home

[@petestorz172]

For about the same displacement as Shokaku, these conversions carried just 65%-70% of the number of planes. Though carrying 15-20 fewer planes, the USN Independence class CVLs were probably more effective, since they could steam and keep pace with USN full-sized fleet carriers.

[@johncunningham6928]

True, but the Independence class were originaly light cruisers, not passenger liners...

[@gregorywright4918]

The Shokakus had an extra 2,000 tons and 100 feet in length, which meant a much bigger hanger deck, thus a bigger air group. They had triple the SHP, and engines designed to be run often at the max, compared to the Hiyos breaking down so much due to being pushed too hard. The Independences were less than half her size, but built on the hulls of Cleveland-class cruisers with 4 shafts and 100,000 SHP.

[@petestorz172]

@@gregorywright4918, actually, it looks like I was off by more than that. The Shokakus were ~32,000 tons, the Hiyos ~24,000 tons, and for further comparison, the Yorktowns were ~20,000 tons. The Shokakus were ~125' longer and ~8' wider than the Hiyos. OTOH, the Yorktowns were ~50" longer but ~4.5" narrower The Yorktowns, though smallest, carried the most aircraft or were similar to the Shokakus. The Hiyos carrying 65%-70% of the Shokakus was more due to space efficiency and utilization than simple displacement. WRT the Independence class CVLs, being based on Cleveland class light cruisers, they had more powerful engines (nearly double the Hiyos). My point, though, was that they could operate with the Enterprise and Essexes, having similar speed.

[@jasonz7788]

Awesome thanks 👍

[@cloudy7937]

Personally I love the how the Junyo and Hiyo look, they have the hull form of the Soryu/Shokaku classes with the island shape resembling that of the Taiho and Shinano

[@gbcb8853]

The name Akikaze is immortalised in the sub film "Run Silent, Run Deep". Although its fate was heroic, two years earlier it had been the site of a war crime (Wiki).

[@nowthenzen]

Of note both Hiyō 飛鷹 and Jun'yō 隼鷹 had Double hulls which might explain why they were able to survive all those torpedo hits.

[@michaelsnyder3871]

This is as good a time to discuss the issue of warship speed. The “Fletcher” class has generally been rated at 37 knots, yet by 1944, actually maximum sustained war speed was closer to 32 knots. First, US trials, while being more realistic than Italian or French, did not replicate the actual wartime displacement and conditions that the trial ship would face. The British trials were not only more realistic, but their design requirements also often stated that a certain speed would be maintained six months out of dock, either in the Atlantic or in tropical conditions. A few months at sea and a ship could have an amazing amount of growth on its hull, creating additional resistance. Trials runs were standardized for specific locations to regularize outcomes among different ships. Ships would make faster runs in deep water compared to more shallow water. Machinery wore down, and if not overhauled regularly or replaced, shaft power steadily declined. Despite most machinery being designed with reserve power and thus, could be run at overload conditions, machinery that was run at overload for trials or during service for any amount of time would suffer damage that would reduce service speeds for the rest of a ship’s life. Displacement grew from continued service. Each paint job (lead or oil based paint) on a capital ship, both external and internal, painted over the previous job, would add a couple tons more to displacement. Administrative and life support equipment for peacetime operations could add another couple of tons. And so on and so on. A ship that made 21 knots in 1916 and was not maintained or overhauled regularly and saw the normal progression in gaining displacement, might be hard put to make 18 knots in 1939. Additional issues came from natural growth on the hull. There were resistant paints, the US Navy’s hull paint being the best, even in the opinion of the British. If the ship was not dry-docked periodically, especially in the tropics, growth could lead to speed loss of as much as a ½ knot every six months. To validate a referenced speed or determine a fairly accurate speed under various conditions, the first data needed is what speed at what displacement was made for how long under what conditions. The next step is to determine battle displacement, the optimum displacement a Navy would hope to engage at, where main belts were sufficiently high enough above the waterline, or sufficient reserve buoyancy was maintained or where the liquid filled parts of the torpedo protection system were at optimum fill. For every 1,000 tons difference between trials displacement and battle displacement, reduce speed by a quarter knot for ships over 20,000 tons. For ships between 5,000 and 20,000 tons, take ½ knot off for every 750 tons and for ships less than 5,000 tons take a knot off for every 500 tons. For example, a battleship makes 32 knots at 45,000 tons trial displacement. Optimum battle displacement is 50,000 tons. Speed at that displacement is 32 - (5 x ¼) or 30.75 knots. A cruiser runs at 35 knots at 5,000 tons and battle displacement is 6,500 tons. Battle displacement speed is 35 - (2 x ½) or 34 knots. A 1,500-ton destroyer makes 37 knots, battle displacement is 2,000 tons, so 37 - (2 x 1) or 35 knots. This destroyer maintained the 37 knots for two hours. Our standard is six hours. For each hour above or below six hours, add or subtract one knot for ships under 5,000 tons. The result is a wartime maximum sustained speed at battle displacement of 33 knots. For ships between 5,000 and 20,000 tons, use a ½ knot and for ships over 20,000 tons, use a ¼ knot. This formula works fairly well across a large spectrum of ships. If you look in Fraccaroli’s data tables on Italian warships of WW2 or Conway’s comments, you’ll find the statements that Italian ships would make X knots on trials, but realistically could expect Y knots under wartime conditions. The formulas above help to explain the difference. Another impact was the steadily increasing number of powered mounts and electronics. These required more electrical output from the turbo generators. Each steam plant was designed to produce a given volume of steam which was fed through the propulsion turbines and through the turbo generators. The more steam drawn on by the turbo generators, the less steam for the propulsion plant. An extreme example was the initial tests of the steam catapult by the British after WW2. The test carrier (a “Colossus” class “light” carrier converted to an aviation repair ship), during a series of continual launches, lost speed and eventually came to a complete halt, the propulsion machinery receiving less and less steam, because the steam was being drawn off for the catapult.

[@AGallion]

For a long time I thought Hiyo and Junyo had both survived the war, I never once thought that Hiyo was sunk with Taiho and Shokaku at the Marianas Turkey Shoot.

[@fxgjolteon4781]

Funny you should post a video on Hiyo, I was just thinking about her. After visiting CV-12 about a year ago now, I saw on her (for lack of a better word) kill sheet a carrier, I searched for quite a few months with seemingly no real answer on which CV it was, until I found a document saying it was the Hiyo, is this true?

[@ph89787]

I think that was Zuikaku and that's a joint one with Yorktown.

[@bkjeong4302]

That would be Zuikaku, which was incidentally the killer of the original Lexington (alongside her sister Shokaku).

[@fxgjolteon4781]

I thought the CV-16 Lexington sank Zuikaku

[@ph89787]

@@fxgjolteon4781 let me rephrase that. Yorktown and Hornet damaged Zuikaku at Philippine Sea. Lexington, Essex and Langley sank her at Leyte Gulf.

[@bjorntrollgesicht1144]

Well, one can say she's mid way between a freighter and a carrier.

[@dylanwight5764]

If I had a penny for every time a maritime company with a name that sounds like Kye Zha produced a vessel capable of being converted into an aircraft carrier, I'd have two pennies. Which isn't a lot but it's strange it happened twice!

[@anumeon]

She carriered on 'til the bitter end.

[@dougjb7848]

Get out.

[@Paludion]

The japanese navy really had the capacity to remain an offensive force from beginning to end of WW2, if they had more trained pilots and better aircraft (the Zero was good in 1941-42 but the tide turned when new and improved allied aircraft appeared). That goes to show you need to invest as much in people as in equipment.

[@paulsteaven]

It's really a good thing that their industry can't keep up with the Imperial Japanese military's demand. A6M Zero is already full of compromises even before the war started.

[@AsbestosMuffins]

if the US had better torpedoes earlier on they would have been on the bottom of the ocean in '42 and '43

[@gregorywright4918]

@@AsbestosMuffins Interesting what-ifs on both sides, but note the general IJN propensity for under-armoring their ships and aircraft. They got better range and more bang for the ton, but could not take the hits like the better-protected USN ships.

[@Fulcrum205]

They couldn't replace the Zero because they didn't have an engine of the required horsepower. The late war Japanese fighters like the Ki-84, Ki-100, etc were constantly battling engine problems. You also have to remember that the aircraft that defeated the Zero were already well along in development when the war started. For example Hellcat started in 1938, Corsair in 38, FTD in 1937. I think the early success of the Zero made the Japanese military rather complacent about developing its successor.

[@hanzzel6086]

In 1941, they probably had some of the best pilots in the world. The problem was that their traditions/doctrine prevented experienced pilots from being cycled back to help train/cycled to anothership/unit. So when they came up with a solution to something, it stayed in (and died with) those units and personal. Which left new personnel making the same mistakes and using the same outdated tactics. Which meant that when they started taking heavy loses, their combat potential fell through the floor.

[@haraldhannelius]

The Finns allegedly had a deal with all the companies running carferries between Finland and Sweden to be able to install mine rails on their car decks.

[@Ah01]

Would make big and clumsy minelayers with very limited amount of places in the archipelago to which they would have deep enough passages. Let alone being enormous sitting ducks for any countermeasures.. modern small freighters would be of much more use.

[@redjacc7581]

I guess IJN Yubari is next :P

[@kittyo9633]

Hope so

[@jony663]

Another great video. Towards the end of the video, what was the submarine along her side?

[@Aelvir114]

1:45 That’s definitely not 1941, or any configuration of Kitakami. Looks like a hodgepodge of her in 1941 (because the 10 quad torpedo-tubes) and 1945 (because of the fore and aft twin 127 mm guns). When she had 10 quad torpedo-tubes, her main armament consisted of only 4 single 140 mm/50 guns, while she didn’t get those replaced until 1945, which replaced them with 2 twin 127 mm/40 DP guns in the regular unshielded A1 mounts, where she also had her remaining 6 quad torpedo-tubes (4 quad were removed in 1942) removed. Weirdly, I’ve not seen any instance of her having the A1 Mod 1 shielded mounts shown in the drawing. Her AA in 1941 was just 2 twin 25 mm guns, which was supplemented with an additional 2 triple 25 mm in 1942, and in 1945 it was overhauled to the 2 twin 127 mm/40 DP guns and 31 single and 12 triple 25 mm guns. The drawing seems to show only 2 twin 127 mm/40 DP guns and 18 single and 6 triple 25 mm guns. Definitely seems like her 1945 configuration but her 1941 torpedo armament retained for some reason (I’d imagine the missing 6 triple and 13 single 25 mm AA guns are replaced by the torpedo launchers)

[@Bhoenix]

okay but why did they put ten quad launchers on a ship what the hell were they trying to sink

[@thhseeking]

@@Bhoenix Everything :P

[@ROBERTN-ut2il]

Hiyo, Silver !!

[@christophersnyder1532]

As I recall, Junyo helped ferry many of the survivors of the battleship Musashi, after the Leyte operations. Take care, and all the best.

[@Philistine47]

The IJN's obsession with "clever" deception bites them again. These ships weren't laid down until 1939, by which time Treaty considerations were already null and void; so imagine if they'd just built them as CVs from the start. (Perhaps as repeat _Hiryus?)_ They could have had much more capable ships for the same investment. Though, granted, the quality of the _ship_ is only part of the story with aircraft carriers. Having 50% greater aircraft capacity only matters if you actually have the aircraft to fill the more capacious deck.

[@rupertboleyn3885]

That would've put construction back considerably. They'd have needed to arrange for engines, etc., probably need to use a naval rather than civilian slipway, and so on. They'd also need to find the money, as they'd be paying for the whole (more expensive) ships not just 2/3rds of them. I agree it wasn't the best use of resources, but I think the mistake was made earlier, when the idea was first adopted.

[@EliteF22]

You make a very good point at the end. Being part of carrier division 3, they were given the lowest priority for replenishment. Their airgroup was also constantly poached to replenish the two main divisions.

[@gregorywright4918]

They are 7,000 tons bigger, but only have half the sets of geared turbines and shafts and one third the SHP compared to the Hiryus. They lasted longer, but that was by skipping the first three "major" naval air battles and suffering engine problems in the fourth.

[@marckyle5895]

@@rupertboleyn3885 They would have been commissioned as a fleet carrier just when Japan needed them.

[@westcoaststacker569]

Are those subs/decoys? purpose built for torpedo protection 7:08

[@jermainerace4156]

The number of times "survived but spent the rest of the war as a hulk" happens around the 1943/44 mark is very suggestive of just how badly Japan planned for this war. They really did think they could end in in one big battle, so they never even considered that they might need to replace their entire naval air arm a few times, including the pilots, crews, etc.

[@TheLoremistress]

I love these videos but it always makes me sad when a warship who saw action is scrapped.

[@Engine33Truck]

Interestingly, two of my favorite Japanese aircraft carriers. Idk why I’ve always had a soft spot for them, but I do. I wonder if there’s any intention to try to find what’s left of Hiyō, Taihō, and Shōkaku

[@spoddie]

7:20 翔鶴 is Shō-kaku not Shi-kaku. The English word show (v) is close to the pronunciation of Shō

[@rembrandt972ify]

The official name of the ship was the IJN Hiyo Silver, Away! Sorry, I couldn't resist.

[@kpaasial]

Also applies to USS Ranger.

[@rembrandt972ify]

@@kpaasial Only if it is sailing alone... 🤩

[@comeslittorissaxonici7395]

Or perhaps "Hiyo Silver Lining"?

[@jaydeister9305]

[@williamromine5715]

How was it able to limp home after being hit by so many torpedoes?

[@AbeBSea]

Are those Sen Takas I see moored next to the hulk?

[@thhseeking]

I was wondering the same thing. I had to do some searching, but they're Ha-201 (Sentaka-Shō) subs, not I-201. They were designed as coastal subs. Kind of a Japanese version of the Type XXIII, but a little more elegant.

[@kylelee9474]

🏆

[@whitneychan433]

The junyo was the lucky ship....one of few INJ carriers to survive ww2....

[@mikepette4422]

Hiyo ! Yes Hi Yo to yoo tooo ! 😉😉

[@bluewave2536]

Can you review the only two "battleships" Chinese Navy ever owned? The DingYuan and ZhiYuan?

[@GreyWolfLeaderTW]

Japanese conceals plans for building/converting new ships so they could build up their Navy "At a speed at which the enemy could not match." *United States laughs in pumping out destroyers and liberty ships at a rate of one every two weeks.

[@gregorywright4918]

It did make for a tough 1942, but mid-43 things turned as the new-builds came online.

[@Ragefps]

Everyone seems to love her looks but come on people, the Shokaku class is far more elegant and purposeful

[@bkjeong4302]

Agreed thoroughly.

[@ph89787]

Agreed. But I put the Yorktowns ahead of them.

[@mikepette4422]

Did I just see a design for a cruiser with FOURTY Torpedo tubes ?

[@bkjeong4302]

Yes. Say hello to Kitakami and (some of) her siblings. They were originally your average early interwar light cruisers, but then they got refitted as “torpedo cruisers” capable of launching 40 long lances (20 per broadside)….only to be sent to the Aleutians instead of the Solomons theatre where they’d actually have been of some use, and then get refitted for various other purposes, losing their torpedoes in the process. Drach has a guide on them.

[@Ragefps]

If you got a good thing flaunt it I guess. God forbid a shell/bomb hit set a warhead off though. The thing would go up like an atomic test barge.

[@marckyle5895]

@@Ragefps 19,200 kg (20 tons) of just the torp warheads will ruin your day. Not to mention any possible reloads stashed nearby. It'd look like HMS Invincible at Jutland.

[@marckyle5895]

@@bkjeong4302 "Say hello to my torpy friend"

[@Ragefps]

​@@marckyle5895I would not like to be in formation with her that's for sure​

[@guaporeturns9472]

I am curious about the multi rocket AA armament

[@jamesm3471]

It grossly underwhelmed, and more often than not, blew up its gunners’ faces, making the damage control guys regret their choice in day job…

[@guaporeturns9472]

@@jamesm3471 It seems Japanese maritime AA systems were decidedly inferior to most major navies of the time.

[@bkjeong4302]

@@guaporeturns9472 Significantly worse than the Americans and arguably the British, but I’d still put them ahead of the Germans.

[@guaporeturns9472]

@@bkjeong4302 oh yeah? I didn’t realize Germans were that bad

[@44WarmocK77]

@@guaporeturns9472 depends on the rocket or missile. The R4M was extremely effective, the Taifun, Fliegerfaust and some of the guided SAMs (like Enzian or Wasserfall, but to be fair: these never saw real combat outside of test launches against enemy targets) - not so much. ^^

[@christerschoultz3759]

One question there seems to be no answer to is, where the hell did Japan get the money and steel to build all these ships, like the Yamato-series? The Japanese are short of like all commodities necessary.

[@bkjeong4302]

Steel wasn’t the big bottleneck; the amount of available infrastructure was. As for money….Japan spent about 1/3 of its total budget on its navy (all ships and facilities).

[@Philistine47]

They got the resources they needed vua trade - in the case of iron and steel, largely from trade with the US. That made the eventual US embargo a particular threat.

[@christerschoultz3759]

@@bkjeong4302yes, but what did they sell to afford these huge ships!

[@christerschoultz3759]

@@Philistine47 what did they trade?

[@PLee-vu6mp]

@@christerschoultz3759 that’s a topic I hope asianometry would cover lol

[@brownwrench]

Ed McMahon used Hiyo as a catchphrase

[@williamswenson5315]

Was there a proposed hull named, Silver?"

[@tonypegler9080]

Where the merchant ships sunk by uboats during WW2 covered by insurance or Govt cpmpensation ?

[@Elderberry_Shrub]

Such good-looking ships

[@rupertboleyn3885]

I generally find carriers fairly unattractive, but these two are definitely an exception.

[@himanetotemo9821]

隼鷹（Jyunyou） 飛鷹（Hiyou）

[@scocon8658]

My guess is, while the IJN may have paid for their large carriers with gold, this class of warship was funded by silver. Making the ship, Wait for it... Hiyo Silver. b-dum-tss Puns are presents of mind ;)

[@Muinko]

Kinda miss the early French steam ships now

[@khaelamensha3624]

Mmh we can share a bottle of wine on this 😉

[@matstick199]

Hyio, my name is Skyler White yo

[@kennethwilson8633]

Boom

[@garybrown4449]

Br unarmored car was late WW2 yes .

Interesting how often she was hit by submarine torpedos

[@Bhoenix]

What the hell kind of ship needs 40 torpedo tubes bro what were they planning on fighting, kaijus?

[@michaelusswisconsin6002]

Surprised she wasn’t kicked on the ground by the USN.

[@thereal_TwentySeven]

You know when your using capital ships as transports, that something has gone seriously awry.

[@kanrakucheese]

Operation Magic Carpet?

[@thereal_TwentySeven]

@@kanrakucheese What I meant was the Japanese using Battleships and Carriers to ferry supplies instead of doing... what capital ships are usually supposed to be doing. It shows how crippled they were by that point in the war.

[@bkjeong4302]

@@thereal_TwentySeven To be fair, in the case of battleships, it wasn’t as if any battleships on either side were doing the job of a capital ship (for the most part) by that point in the war. Being turned into a gigantic CLAA or a gigantic monitor isn’t much if at all of an improvement over being the world’s most heavily armed military transport.