800kg bombs at Midway

According to Shattered Sword, the B5Ns in the Japanese attack on Midway June 4 carried 800kg land attack bombs, presumably a general purpose HE weapon. It seems an odd choice to me. There would not seem to any targets on Midway which would require a weapon of this power, nor AFAIK were they aiming for precise targets. At Pearl Harbor B5Ns on land attack carried one 250kg and six 60kg bombs, 610kg total, less total weight but likely better coverage against dispersed targets like aircraft, revetments, gun positions, etc.

One thing the Japanese were not trying to do was crater the runways on Eastern Island, since they hoped to be using them themselves in a couple of days. So what were the 800kg bombs for?

 

I believe the targets for the B5Ns from Soryu were the aircraft hangers on the eastern part of Midway. Just a guess, but maybe the Japanese wanted to ensure that there would be no support infrastructure left for landing American fighters and bombers? Theoretically, the bombs would only have wiped out the hangers and equipment, and not damage the runways.

You raise a good question.

 

Possible bunker busters...

 

No. Unless they were dive bombers carrying these bombs, bunker busters would be inaccurate to say the least.

 

Okay...how bout destroying under ground networks then...?

 

Looking at List of Japanese World War II navy bombs - Wikipedia, the free encyclopedia
The No.80 which it mentiones as having been used at Midway looks like it might have been characterized as a SAP as it "will penetrate 400 mm of reinforced concrete.[SUP]"[/SUP]

 

Didn't they convert 16 inch naval shells into bombs? Seems like they'd weigh about the same-1600lbs ish.

 

Didn't they convert 16 inch naval shells into bombs? Seems like they'd weigh about the same-1600lbs ish.

Yes, and they are also listed as 800kg, but they were armor-piercing, specifically for use against our battleships. SS describes the weapons at Midway as land attack bombs, unfortunately no further detail, but that sounds like a GP/HE type weapon.

It seems puzzling that they would use any type 800kg bombs against the defenses or facilities at Midway - at least it's got me puzzled.​

 

The #80 in the Japanese lexicon was a Land Bomb, and should actually be considered somewhere between GP and SAP. The modified 16" AP shells (Type 99 #80 & Type 2 #80) had bursting charges somewhere between 2.8% and 4.4% depending on the Type & Model, the Type 2 #50 Model 1 SAP had a bursting charge of 12.5% - they were for naval targets. The thin skinned #50 & #80 Land bombs had bursting charges of around 40%. In short, they had some penetration, and alot of blast.

The Kate level bombers from Soryu & Hiryu were scheduled to hit Eastern & Sand Is. coming in from the NE to start off the proceedings, targeting aviation type soft targets i.e. fuel tanks, hangers, PBYs ... and the runways on Eastern Is. Tactical surprise if achieved would hole the runways, preventing takeoff, while the blast could level the area, toss any ready aircraft etc., the Vals could then attack the hard points - in theory anyway.

You have to wonder what Nagumo thought when his carriers came under attack from B-17's while his Midway strike force was waiting to land???

I think Parshall & Tully were more inclined to quote things like Japanese carrier CAP #'s, times, pilot's names etc. in order to dispell myth veiled as fact, than to tell the whole Midway story.

 

In the attack on Midway Island, the Hiryu expended 17 #80 bombs and the Soryu expended 18 #80 bombs.

The airfield was most definitely a main target of the #80s, since the Japanese themselves hit it with some 12 #80 bombs.

See here:Japanese Story of the Battle of Midway

After all, repairs to a bomb damaged runway can be quickly accomplished. So, I don't think that the would be too concerned if Midway's airfield was well cratered when they landed. Since they would likely have it operational again in hardly any time.

 

Takao,

While it appears under "The Japanese Story of Midway", in reality it's Nagumo's After-Action Report i.e. "Action Report by the C-in-C of the First Air Fleet" from 1942. It's not a balanced Japanese account at all, and it's hugely self-serving, not a bit of scholarship. For example check out the losses claimed over Midway; those 12 #80 bomb hits on the runways were what his pilots claimed - 1 in 3 hit the runways? - not likely, the pilot's claims were hugely inflated, the runways were indeed targtted, but as to the rest? He left out all kinds of things, such as the US PoW's were interogated then murdered, and dropped in the sea, the list goes on, missing logs, deliberate lies... some are debatable as to what he knew and didn't, I would take it all with a huge grain of salt.

 

Wondered about : "The enemy, however, having lost two of their powerful carriers and many of his air personnel, would undoubtedly be unable to effect any large-scale operation in the near future. It is believed that the enemy will surely strike back at some time, and every precaution should be taken against this." -Weren't there large scale operations after this event? Guess it depends upon definition of "near future"?

 

Nagumo was wrong of course, the USN had only lost Yorktown, the Japanese (by that time, down to just Hiryu) had attacked her twice, but thought they had struck 2 different Yorktown Class ships. The US would embark on what became the Guadalcanal Campaign shortly thereafter, large enough for the Japanese as it turns out.

 

In what way were the authors wrong?

 

Whom are you quoting? The USN or the IJN?

 

I think the first sentence is a effort to put a positive spin on the outcome. 'See! We kicked ass, they wont be back soon!' The second sentence is a cover the ass statement. "..at sometime," is awfully vague & 'sometime' might be anywhere from a month to a year.

My take is the IJN leadership was becoming nonplussed by the US not yet asking for a armistice. The Pacific war was their show and the lack of a defeated US was a tad embarassing. Failing to gain the objectives at Midway was one level of losing face, but losing four carriers was major league embarassing.

 

I didn't say Parshall & Tully were wrong, not at all. I consider their work to be 1st rate; it's well researched and noted, has an extensive bibliography, and worthwhile appendices. I highly recommend it, but not as the complete story of Midway. Rather, it is the story of the Japanese "Shattered Sword", using many works of Japanese research. Taken in its entirety, the book's over 600 pages long, of that, the physical attack on Midway amounts primarily to Japanese pilot after action reports and takes up 4 pages, plus a diagram; not exactly all inclusive, little of the American account is included anywhere in this book, the author's acknowledge this.

Instead Parshall & Tully focused primarily on 3 sources that until their book, had undo influence on US works on the Battle of Midway, sources that were flawed that they were out to refute. They are; the "Nagumo Report" (which Takao provided a link to), the US Strategic Bombing Survey, basically post-war interviews of Japanese officers, and "Midway, The Battle That Doomed Japan", by Fuchida Mitsuo/Okumiya Masatake. They do an admirable job of doing so; "quote things like Japanese carrier CAP #'s, times, pilot's names etc." was part of the process "in order to dispell myth veiled as fact,".

 

The primary battle that the authors wanted to tell was the destruction of the IJN carriers. While including more info about the attack on Midway Island itself would have been nice; this was not of real importance on what was unfolding back at the US and IJN carrier groups.

 

... very succinct and to the point. And here I thought you wanted an argument in defence of my statement, silly me.