Historic Battle of Midway wrecks surveyed

[Minmus Taster]

The aircraft carriers Akagi, Kaga, and Yorktown have been surveyed. Yorktown was discovered by Robert Ballard years ago but hadn't been seen since and Kaga was located recently in 2019. Akagi was also located that year but only via sonar and is just now being dived on. The two other Japanese carriers, Soryu and Hiryu, have not been found.

USS Yorktown:

Spoiler

USS Yorktown was located by Dr. Robert Ballard in 1998. She's lying intact on the sea bed perfectly preserved at a depth of 5074 Meters. She's listing onto her starboard side but mostly intact. The recent survey found her in much the same condition as when she was first identified.

The Yorktown's superstructure.

The Yorktown's Stern

IJN Kaga:

Spoiler

While light debris from the ship was found in 1999 the wreck of the Kaga wasn't located until 2019. Her wreck is in far worse shape then her American counterpart. She's lying at a depth of around 5400 Meters and is totally destroyed. Kaga was hit by multiple bombs which ignited her hanger decks causing explosions so massive that men from other ships thought it must have killed everyone on board. Everything above her original Battlecruiser hull has broken up and is lying around the ship. The ships is almost totally buried with the bow of the ship being covered in silt. The devastation is so widespread that many points don't resemble a ship at all, let alone an aircraft carrier.

A recognizable section of Kaga's hull.

A surviving turret, a rare sight on Kaga's mangled wreck.

A strangely unsettling images of the wreck.

IJN Akagi:

Spoiler

IJN Akagi was found the same year as her fleetmate in 5490 Meters of water but was not surveyed until this year. She's more intact then her sister (though it's sadly a low bar), the former flagship of the Japanese force that day is in a sorry state on the bottom. She sustained slightly less severe damage then Kaga but still suffered the same violent end to internal explosions. The recent survey found that the ship has some damage but still has recognizable features unlike the Kaga.

The Bow of Akagi, with the intact seal of the emperor still on her bow.

A damaged portion of the Akagi's superstructure

Possibly an anchor off Akagi's stern

And here's the video these images were taken from:

 

Edited September 17, 2023 by Minmus Taster

[tater]

Very cool.

IMO, the best book on the battle itself by far is called Shattered Sword. It debunks a number of myths that largely entered English language histories after the book Midway: The Battle That Doomed Japan by Mitsuo Fuchida and Masatake Okumiya.

 

[SunlitZelkova]

I once had an email correspondence with one of the authors of Shattered Sword. I was only 13 at the time and my question was kind of dumb (“what would have happened if Yamamoto survived his shoot down?”) but he kindly provided a response.

I later joined their online forum called Tully’s Port. Lots of nice discussions there about the book and other topics related to the Pacific War.

[tater]

What's interesting about that book is that is is very much centered on the IJN, and their doctrine, etc. Fuchida's book you would think would be the same—as the author was actually there—but many elements of the battle that have been well understood in the Japanese literature are very much not what Fuchida presented. That said, when I was a kid and had just read Fuchida, my dad's publishing company came out with some kid's books on WW2, and after I read them I sent the editor a long list of errors in every book, many of which in the Midway kid's book I corrected with references to Fuchida (happily none were the issues the Shattered Sword debunks).

[magnemoe]

18 hours ago, tater said:

What's interesting about that book is that is is very much centered on the IJN, and their doctrine, etc. Fuchida's book you would think would be the same—as the author was actually there—but many elements of the battle that have been well understood in the Japanese literature are very much not what Fuchida presented. That said, when I was a kid and had just read Fuchida, my dad's publishing company came out with some kid's books on WW2, and after I read them I sent the editor a long list of errors in every book, many of which in the Midway kid's book I corrected with references to Fuchida (happily none were the issues the Shattered Sword debunks).

Yes, one of the old debunked Fuchida's ideas it that the decks of the Japanese carriers was full of planes who was reloading who was false, the planes was still in the hangar.  Something I imagine the US dive bomber pilots would see and probably also show on cameras on the planes. Planes filled with petrol in an enclosed hangar then an bomb exploding there is also much more an problem than on the flight deck. 
Probably that Kaga hangar went up as an fuel air bomb who might set off more stuff but its very hard to set off military explosives 

[FleshJeb]

I've never read Shattered Sword, but Jon Parshall is a frequent guest on this podcast. it's a fun ride:

https://www.youtube.com/@UnauthorizedHistoryPacificWar/videos

[tater]

On 9/18/2023 at 8:40 AM, FleshJeb said:

I've never read Shattered Sword, but Jon Parshall is a frequent guest on this podcast. it's a fun ride:

https://www.youtube.com/@UnauthorizedHistoryPacificWar/videos

Thanks for this. Now in my podcast feed. Quite good.

[tater]

Only issue with the podcast so far is them characterizing the F4F as outclassed by the A6M (Zero). This is flatly wrong. The Zero was a nice airplane, and while it outperformed the F4F in a few ways, it underperformed in a few ways that absolutely leveled the playing field.

Zero had longer range, better maneuverability (in most speed regimes, but not all), and 20mm guns in the wings.

F4F, depending on version was faster flat out at sea level (regardless both were within a few knots of each other), and while 0.50 cal was objectively  less destructive than 20mm per rnd, they had more firing time, and longer range—most importantly, Japanese aircraft were incredibly vulnerable to damage. The last plus for the F4F was ability to absorb damage. So USN/USMC pilots could learn from mistakes that IJN pilots could not—because the latter got hit with a few API rounds, and went down in flames, while many US pilots landed F4Fs with literally 100s of holes in them.

F4F never had a K/D <1 with the Zero. The two aircraft were a very close match.

I might have to send them an email

Edited September 22, 2023 by tater

[SunlitZelkova]

4 hours ago, tater said:

Only issue with the podcast so far is them characterizing the F4F as outclassed by the A6M (Zero). This is flatly wrong. The Zero was a nice airplane, and while it outperformed the F4F in a few ways, it underperformed in a few ways that absolutely leveled the playing field.

Zero had longer range, better maneuverability (in most speed regimes, but not all), and 20mm guns in the wings.

F4F, depending on version was faster flat out at sea level (regardless both were within a few knots of each other), and while 0.50 cal was objectively  less destructive than 20mm per rnd, they had more firing time, and longer range—most importantly, Japanese aircraft were incredibly vulnerable to damage. The last plus for the F4F was ability to absorb damage. So USN/USMC pilots could learn from mistakes that IJN pilots could not—because the latter got hit with a few API rounds, and went down in flames, while many US pilots landed F4Fs with literally 100s of holes in them.

F4F never had a K/D <1 with the Zero. The two aircraft were a very close match.

I might have to send them an email

The First Team: Pacific Naval Air Combat from Pearl Harbor to Midway by John Lundstrom covers this nicely.

Having read this book, I think there were two the key things that made USN flyers ultimately prevail over the IJNAS, rather than aircraft themselves-

1. The USN practiced deflection shooting. This is when you shoot at a target while it is turning. It seems like an obvious thing if you’re like me and play combat games like War Thunder a lot, but very few air forces did this at the time. The IJN was stuck trying to get on the tails of fighters before they could fire a shot.

2. Radar ground control intercepts. The IJN had nothing like this, and it gave the USN a huge edge in intercepting incoming strikes.

Both sides were a really interesting bunch though. The First Team details the profiles of each pilot, and gives a fair bit of detail on the Japanese side too. If the late war was characterized by masses of Hellcats and Corsairs flying against inexperienced kamikazes, the early war had some of the finest airmen to ever face off against each other.

At the same time, I think superior tactics and intelligence on the part of the Americans leveled the playing field more than the average history accepts.

[tater]

24 minutes ago, SunlitZelkova said:

The First Team: Pacific Naval Air Combat from Pearl Harbor to Midway by John Lundstrom covers this nicely.

Yeah, both books (which I have).

25 minutes ago, SunlitZelkova said:

Having read this book, I think there were two the key things that made USN flyers ultimately prevail over the IJNAS, rather than aircraft themselves-

It helped of course that the two aircraft were in fact very evenly matched. From my gajillion hours flying ww2 combat sims, I actually prefer the F4F-3 to the folding-wing -4, because the -3 has about the same ammo load, but only 4 guns (the later Eastern built (the aircraft name for General Motors) Wildcats were also 4 guns)—leaving it with substantially more firing time. On the -4 I actually don't use the outer 2 guns and save them just in case I go Winchester on the other 4. Sims are not real life, obviously, but the accounts of battles (Lundstrom is awesome), do show the incredible advantage of survivability.

I actually think from a doctrinal POV, the IJN had it exactly wrong given the highly selective and rigorous nature of their pilot training (Sakai's book, Samurai!, among others details this). They worked hard to create fantastic pilots, then put them in an aircraft absolutely focused on "offensive" capability to a fault. They rejected so many candidates, their stable of up and coming pilots was not high enough to meet the demands of a total war. In combat units, their radios were sort of marginal, so many pilots removed them to save weight—for more maneuverability! Pilot armor? LOL—heavy! Self-sealing gas tanks? Those are also heavy!  Many pilots also elected not to take the parachutes they were issued. The next result was great, but completely irreplaceable pilots. As fresh pilots came to the front, this was exacerbated, because the vets had the early war combat experience when they dominated to fall back on, but the new guys had to learn on the job, where literally any mistake was often deadly. The USN (USMC/USAAF as well) had by Japanese measures, an effectively endless stream of new pilots—"good enough" as the training was not nearly as selective. These good enough pilots could improve in combat because they could actually make mistakes and still get home—then learn from those mistakes.

"Good judgment comes from experience; experience comes from bad judgment"

Hard to get the former when bad judgement is fatal.

The US could have afforded (in terms of pilots) to make an especially capable, but more vulnerable aircraft—the Japanese really didn't have that luxury, IMHO. They would have done better preserving their pilots, even if it was against their offensive... spirit.

They really did the same with ASW doctrine. Unpopular posting because considered "defensive." So the US submarine service absolutely wrecks their merchant marine. USN SS force killed way less tonnage than the U-boats—but the U-boats had ~0 impact on tonnage shipped (only 1-2% of ships in convoys sunk over the whole war), and the US Fleet Boats sank nearly all the Japanese Merchant Marine.

[DerekL1963]

On 9/21/2023 at 10:11 PM, tater said:

They really did the same with ASW doctrine.  Unpopular posting because considered "defensive." So the US submarine service absolutely wrecks their merchant marine. USN SS force killed way less tonnage than the U-boats—but the U-boats had ~0 impact on tonnage shipped (only 1-2% of ships in convoys sunk over the whole war), and the US Fleet Boats sank nearly all the Japanese Merchant Marine.

You really do have to be careful comparing Allied apples to Japanese oranges.  The U-boats had less effect on the Allied war effort than you might think because we built Liberty and Victory ships by the gross lot.   On the other hand, the Japanese started the war with the merchant marine on the back foot - they didn't have enough but to barely supply their civilian needs, let alone the expanded needs of wartime industry.  And they never managed to climb out of that hole.  They simply couldn't (and didn't) build enough shipping to make up for their losses.  Thus it's not clear that improved ASW doctrine would have helped much, because they couldn't mass produce the escorts needed to implement that doctrine.

You also have to consider that the main strength of the Allied ASW effort wasn't just better doctrine or having sufficient capable escorts...   It was hunter killer groups (built around the baby carriers the Japanese didn't have and couldn't build.)  It was long range maritime patrol aircraft.  And not just Coastal Command in the Bay of Biscay! (To which there couldn't be a Japanese equivalent, because the US sub bases weren't in range of any reasonable aircraft.) The Liberators out of Iceland had a huge effect - and they were essentially spares strategic bombers (which the Japanese didn't have).  It was about Huff Duff (high frequency direction finding) which exploited Doenitz's requirement that U-boats frequently phone home (which US subs in the Pacific didn't do).  And Ultra/Enigma.  And littler things like radar (which the Japanese never quite managed to master and put into mass production), and Leigh Lights.  Etc... etc...

The Battle of the Atlantic turned out different from the Battle of the Pacific because the Allies put a great deal of effort into the Battle of the Atlantic which the Japanese didn't have to put into a mirror equivalent in the Pacific.

[tater]

19 minutes ago, DerekL1963 said:

You really do have to be careful comparing Allied apples to Japanese oranges.  The U-boats had less effect on the Allied war effort than you might think because we built Liberty and Victory ships by the gross lot.   On the other hand, the Japanese started the war with the merchant marine on the back foot - they didn't have enough but to barely supply their civilian needs, let alone the expanded needs of wartime industry.  And they never managed to climb out of that hole.  They simply couldn't (and didn't) build enough shipping to make up for their losses.  Thus it's not clear that improved ASW doctrine would have helped much, because they couldn't mass produce the escorts needed to implement that doctrine.

Absolutely true. Mark Parillo's excellent book is a fine reference here. But while they did not have enough merchant shipping, they were also really lax about defending what they had. How many Kaibokan could have been built with the metal wasted on Yamato and her sisters? They also of course lacked opsec (regular signal intelligence was important, but so was code breaking). WRT the u-boats, though, aside from codebreaking, and sigint (they were a chatty Kathy force, a bad idea for submarines), the reality is that convoying with escorts was highly effective. Once we started doing that, sinkings plummeted. The IJN never did anything as complete as USN/RN convoy doctrine.

25 minutes ago, DerekL1963 said:

You also have to consider that the main strength of the Allied ASW effort wasn't just better doctrine or having sufficient capable escorts...   It was hunter killer groups (built around the baby carriers the Japanese didn't have and couldn't build.)  It was long range maritime patrol aircraft.  And not just Coastal Command in the Bay of Biscay! (To which there couldn't be a Japanese equivalent, because the US sub bases weren't in range of any reasonable aircraft.) The Liberators out of Iceland had a huge effect - and they were essentially spares strategic bombers (which the Japanese didn't have).  It was about Huff Duff (high frequency direction finding) which exploited Doenitz's requirement that U-boats frequently phone home (which US subs in the Pacific didn't do).  And Ultra/Enigma.  And littler things like radar (which the Japanese never quite managed to master and put into mass production), and Leigh Lights.  Etc... etc...

The Battle of the Atlantic turned out different from the Battle of the Pacific because the Allies put a great deal of effort into the Battle of the Atlantic which the Japanese didn't have to put into a mirror equivalent in the Pacific.

All very true.

The trick is that the Japanese—an island nation like the UK—knew all this ahead of time. The whole point of the war was to secure resources in the planned wider Empire (arguably the NEI was the whole point). For a bunch of guys who planned their initial push outwards so effectively, they utterly failed to think about the logistics. Course I think the Axis writ-large was an abject failure at logistics.

[DerekL1963]

1 hour ago, tater said:

How many Kaibokan could have been built with the metal wasted on Yamato and her sisters?

You do have to be careful with that line of thought...  In 1937, the Japanese had no idea that WWII wouldn't turn out the way they thought it would.  Plus it runs counter to IJN doctrine of the era, which favored a small number of technologically and operationally superior units.  (That the Yamato would turn out to be neither until she was refitted with Wave Motion technology was also unknown to them.)  And that doctrine was in turn based on the reality that they well understood - they could not hope to compete with US in numbers or over the long run.  They simply lacked the industrial capacity and easy access to the needed resources.
 

1 hour ago, tater said:

For a bunch of guys who planned their initial push outwards so effectively, they utterly failed to think about the logistics. Course I think the Axis writ-large was an abject failure at logistics.

As I said above, the Japanese (more the IJN than the IJA) certainly understood their position with relationship to the industrial capacity of the US.  But rather than deterring them from war, it lead them into the clutches of that wily seductress, the short war fallacy.  (The IJN were also inclined to that by their near religious devotion to Mahan's increasingly outmoded doctrines.)

[tater]

Yes. 
 

They kept losing the “decisive battle” and not realizing it. Regardless, they also did try to mirror the RN, and WW1 provided an object lesson i the power of submarines to disrupt commerce.

As I said, it was a doctrine failure, as was pilot training vs aircraft design choices. Same problem. Capable offensive surface units for their offensive doctrine, and short war goals vs units to protect commerce. Maneuverable  but vulnerable aircraft that don’t protect the irreplaceable aircrew. Also favors short war.

Edited September 26, 2023 by tater

[tater]

Yamamoto realized the power of the US economy, and suggested they needed to win in 6 months, then decided to launch an attack that was guaranteed to competely enrage us, making a short war impossible. Even had the declaration of war arrived on time, which was to plan “just in time,” the US is still  enraged I think. Course that makes little difference, we had a war plan (Orange), and with small changes of specific locations it’s exactly what we did.

[SunlitZelkova]

1 hour ago, tater said:

They kept losing the “decisive battle” and not realizing it. Regardless, they also did try to mirror the RN, and WW1 provided an object lesson i the power of submarines to disrupt commerce.

Rather than a “decisive battle”, I think the problem for Japan was that the battle ended up being a campaign. The Solomons operations in late ‘42 to 43 drained the IJN of a lot of strength and experienced pilots as much as, if not more than Midway did, and Japan just had no chance of keeping up with the US ability to replace losses.

Lack of surface search radar didn’t help either, and gave the US an edge despite excellent Japanese night-fighting capabilities.

1 hour ago, tater said:

Even had the declaration of war arrived on time, which was to plan “just in time,” the US is still  enraged I think.

That wasn’t a declaration of war, just a notification they were abandoning diplomacy. So the US would be enraged even if the 14 part document arrived on time.

IIRC the US actually decoded the whole message ahead of the Japanese embassy.

[tater]

37 minutes ago, SunlitZelkova said:

Rather than a “decisive battle”, I think the problem for Japan was that the battle ended up being a campaign. The Solomons operations in late ‘42 to 43 drained the IJN of a lot of strength and experienced pilots as much as, if not more than Midway did, and Japan just had no chance of keeping up with the US ability to replace losses.

Yes.

Again, irreplaceable pilots. And they never had the logistical capability to maintain a far-flung empire.

39 minutes ago, SunlitZelkova said:

That wasn’t a declaration of war, just a notification they were abandoning diplomacy. So the US would be enraged even if the 14 part document arrived on time.

It was effectively their declaration, it ended all negotiations (de facto war, therefore).

Would not have changed the war much—but a more politically savvy policy would have tried to to not start a war with the US. They might have had a crack at just declaring war on the NEI (Netherlands already occupied by their ally, Germany). Maybe also the UK, then play to India to join them. They'd have to do something neither of the Axis did to have a chance—treat the people they invade as liberated friends, instead of subhuman slaves. Such a counterfactual might have been slightly less likely to fail.

[RCgothic]

The battle between F4Fs and Zeros with one side suffering disproportionate casualties brings to mind a "Lanchester Square Collapse".

Also it would appear that Zeros favouring heavy short-range firepower and manoeuvrability folds in with the doctrine of getting on the target's tail rather than deflection shooting where more individual shots from further away might be more useful.

[magnemoe]

On 9/22/2023 at 7:11 AM, tater said:

Yeah, both books (which I have).

It helped of course that the two aircraft were in fact very evenly matched. From my gajillion hours flying ww2 combat sims, I actually prefer the F4F-3 to the folding-wing -4, because the -3 has about the same ammo load, but only 4 guns (the later Eastern built (the aircraft name for General Motors) Wildcats were also 4 guns)—leaving it with substantially more firing time. On the -4 I actually don't use the outer 2 guns and save them just in case I go Winchester on the other 4. Sims are not real life, obviously, but the accounts of battles (Lundstrom is awesome), do show the incredible advantage of survivability.

I actually think from a doctrinal POV, the IJN had it exactly wrong given the highly selective and rigorous nature of their pilot training (Sakai's book, Samurai!, among others details this). They worked hard to create fantastic pilots, then put them in an aircraft absolutely focused on "offensive" capability to a fault. They rejected so many candidates, their stable of up and coming pilots was not high enough to meet the demands of a total war. In combat units, their radios were sort of marginal, so many pilots removed them to save weight—for more maneuverability! Pilot armor? LOL—heavy! Self-sealing gas tanks? Those are also heavy!  Many pilots also elected not to take the parachutes they were issued. The next result was great, but completely irreplaceable pilots. As fresh pilots came to the front, this was exacerbated, because the vets had the early war combat experience when they dominated to fall back on, but the new guys had to learn on the job, where literally any mistake was often deadly. The USN (USMC/USAAF as well) had by Japanese measures, an effectively endless stream of new pilots—"good enough" as the training was not nearly as selective. These good enough pilots could improve in combat because they could actually make mistakes and still get home—then learn from those mistakes.

"Good judgment comes from experience; experience comes from bad judgment"

Hard to get the former when bad judgement is fatal.

The US could have afforded (in terms of pilots) to make an especially capable, but more vulnerable aircraft—the Japanese really didn't have that luxury, IMHO. They would have done better preserving their pilots, even if it was against their offensive... spirit.

They really did the same with ASW doctrine. Unpopular posting because considered "defensive." So the US submarine service absolutely wrecks their merchant marine. USN SS force killed way less tonnage than the U-boats—but the U-boats had ~0 impact on tonnage shipped (only 1-2% of ships in convoys sunk over the whole war), and the US Fleet Boats sank nearly all the Japanese Merchant Marine.

The US also rotated experienced pilots back to train the new one, they was even better than the old pre war trainers as they had recent combat experience. 
US also trained hundreds of thousands or pilots, the ones just passed was second pilot on heavy bombers or transports the top ones flew from carriers.  
In both Japan and Germany it was an lack of fuel to train new pilots anyway but this was more an problem later I think. 

In short Japan and Germany planed for an short less than an year long war as they knew they could not win an long one. 

[tater]

3 hours ago, RCgothic said:

The battle between F4Fs and Zeros with one side suffering disproportionate casualties brings to mind a "Lanchester Square Collapse".

Also it would appear that Zeros favouring heavy short-range firepower and manoeuvrability folds in with the doctrine of getting on the target's tail rather than deflection shooting where more individual shots from further away might be more useful.

Longer firing time on the .50s means the pilots can do that, and have more opportunities to fire—and improve their shooting. A6M only had 60 rpg on the 20mm. The 0.30 cal cowl guns were effectively useless vs USN fighters.

The best features of the Zero were the range (huge), and the rate of climb. That fact that it could turn well is fine in a turn fight, but the best possible way to fly the A6M is to make a pass, then climb away. The 2 aircraft (F4F-4) had identical flat out speed, the -3 was a couple mph faster on the deck—the ROC of the F4F was grossly lower. It was like 2/3 the ROC of the Zero. So 1 v 1, in an even fight, if the Zero doesn't control the fight he's doing something wrong. Course fights are never even in the real world—generally if they are even you've already done something wrong. The Japanese fighter aircraft at the start of the war (IJN, and IJA) did so very well not because their planes were better, and not always just because they had veteran pilots (experience in China), but because they were, as is said, "the firstest with the mostest." If you're the RAF in Burma, and 50 aircraft come sweeping over your airfield as you try to get airborne with 6 fighters—you're going to have a Bad Time™. Doesn't matter if they are Brewster Buffaloes (the aircraft with the best K/D of the war, BTW, in the hands of the Finns), Hurricanes—or even if they were given F6Fs via time machine.

It doesn't seem to get talked about this way in many histories, but the fact that US pilots could learn from mistakes I think is important. Also, they'd get rotated home to train up new pilots, so the green aircrew at least had the combat experience of their trainers imparted to them—vs flying off Rabaul until you were dead for the Japanese.

2 hours ago, magnemoe said:

The US also rotated experienced pilots back to train the new one, they was even better than the old pre war trainers as they had recent combat experience. 

I just read this after saying the same thing, lol.

[Minmus Taster]

It's been awhile but I wanted to share some images I found off various sites of Akagi and Kaga.

Kaga:

Spoiler

A better view of some of the miraculously intact casemates on the port side

A collapsed portion of hull at the severed stern, Kaga's fantail broke off when she sank.

Akagi:

Spoiler

Anti aircraft guns still attached to the wreck, Akagi is actually more intact than I first thought, large portions of the ship are actually intact up to the flight deck level.

Above the Akagi's sleek battlecruiser bow, the ship's hull is quite badly buried in the mud, at some places even deeper than Kaga.

A section of flight deck peeled back like a tin can, while akagi's profile is recognizable the flight and hanger decks have collapsed downward leaving what one historian described as a 'bathtub' shape.

The side of akagi's hull underneath what's left of her bridge, another anti aircraft gun is visible.

A blurry image of a casemate, similar to what was seen on Kaga, this image alone tells you Akagi is much better preserved than her fleetmate.

Not actually sure what this is, the reddit post I found this on claimed it was 'near miss' damage from one of the bombs that hit to the side of the ship.

Over the stern of the Akagi

The name of the Akagi has been painted over to hide the ships identity during the battle, but the researchers  could still make out the outline of 'Akagi'.

There are more images including ones from other expeditions I did not include.

[magnemoe]

On 12/4/2023 at 4:19 PM, Minmus Taster said:

It's been awhile but I wanted to share some images I found off various sites of Akagi and Kaga.

Kaga:

  Hide contents

A better view of some of the miraculously intact casemates on the port side

A collapsed portion of hull at the severed stern, Kaga's fantail broke off when she sank.

Akagi:

  Hide contents

Anti aircraft guns still attached to the wreck, Akagi is actually more intact than I first thought, large portions of the ship are actually intact up to the flight deck level.

Above the Akagi's sleek battlecruiser bow, the ship's hull is quite badly buried in the mud, at some places even deeper than Kaga.

A section of flight deck peeled back like a tin can, while akagi's profile is recognizable the flight and hanger decks have collapsed downward leaving what one historian described as a 'bathtub' shape.

The side of akagi's hull underneath what's left of her bridge, another anti aircraft gun is visible.

A blurry image of a casemate, similar to what was seen on Kaga, this image alone tells you Akagi is much better preserved than her fleetmate.

Not actually sure what this is, the reddit post I found this on claimed it was 'near miss' damage from one of the bombs that hit to the side of the ship.

Over the stern of the Akagi

The name of the Akagi has been painted over to hide the ships identity during the battle, but the researchers  could still make out the outline of 'Akagi'.

There are more images including ones from other expeditions I did not include.

Casemate guns on a aircraft carrier make so much sense, all other was dropping them from battleships  The was very close to the waterline, probably why they survived so they would be wet something who was an major issue with casemates in addition as you could not use them for anti air. 
Yes back before WW 2 it was an fear that carriers could be involved in gun action during night as night carrier operation was not an thing.  In fact the first aircraft carrier clash in WW 2 was almost an nighttime gun duel between British and Japanese carriers, that would thrown an curve ball in designs  Now the US had an more sensible design with the 4 dual 6" guns forwards and back of the tower, they was later replaced with 5" dual role guns. 
For its better to have an cruiser escorting the carrier to protect it against surface attacks and add more AAA. Or better an Iowa class battleship who are so fun to fight at night.