WW2 USN Strategic Bombing Capability

[wuzak]

From the USSBS:

The total tonnage of bombs dropped by Allied planes in the Pacific war was 656,400. Of this, 160,800 tons, or 24 percent, were dropped on the home islands of Japan. Navy aircraft accounted for 6,800 tons, Army aircraft other than B-29s for 7,000 tons, and the B-29s for 147,000 tons. By contrast, the total bomb tonnage in the European theater was 2,700,000 tons of which 1,360,000 tons were dropped within Germany's own borders.

Approximately 800 tons of bombs were dropped by China-based B-29s on Japanese home island targets from June 1944 to January 1945. These raids were of insufficient weight and accuracy to produce significant results.

By the end of November 1944, 4 months after seizure of the islands, the first of the long-range bomber bases in the Marianas became operational. The number of planes originally available was small and opposition was significant. Losses on combat missions averaged 3.6 percent. The tonnage dropped prior to 9 March 1945 aggregated only 7,180 tons although increasing month by month. The planes bombed from approximately 30,000 feet and the percentage of bombs dropped which hit the target areas averaged less than 10 percent. Nevertheless, the effects of even the relatively small tonnage hitting the selected targets were substantial. During this period, attacks were directed almost exclusively against aircraft, primarily aircraft engine, targets. The principal aircraft engine plants were hit sufficiently heavily and persistently to convince the Japanese that these plants would inevitably be totally destroyed. The Japanese were thereby forced into a wholesale and hasty dispersal program. The continuing pressure of immediate military requirements for more and more planes during the campaigns in the Pacific had prevented any earlier moves to disperse. When dispersal could no longer be avoided, the necessary underground tunnels, dispersed buildings, and accessory facilities such as roads, railroad spurs and power connections were not ready. As a result the decline in aircraft engine production, which shortages in special steels requiring cobalt, nickel and chrome had initiated in mid-1944, became precipitous.

On 9 March 1945, a basic revision in the method of B-29 attack was instituted. It was decided to bomb the four principal Japanese cities at night from altitudes averaging 7,000 feet. Japanese weakness in night fighters and antiaircraft made this program feasible. Incendiaries were used instead of high-explosive bombs and the lower altitude permitted a substantial increase in bomb load per plane. One thousand six hundred and sixty-seven tons of bombs were dropped on Tokyo in the first attack. The chosen areas were saturated. Fifteen square miles of Tokyo's most densely populated
area were burned to the ground. The weight and intensity of this attack caught the Japanese by surprise. No subsequent urban area attack was equally destructive. Two days later, an attack of similar magnitude on Nagoya destroyed 2 square miles. In a period of 10 days starting 9 March, a total of 1,595 sorties delivered 9,373 tons of bombs against Tokyo, Nagoya, Osake, and Kobe destroying 31 square miles of those cities at a cost of 22 airplanes. The generally destructive effect of incendiary attacks against Japanese cities had been demonstrated.

Thereafter, urban area attacks alternated with visual and radar attacks against selected industrial or military targets. In April, an extensive program of sowing minefields in channels and harbors at night was added. In the aggregate, 104,000 tons of bombs were directed at 66 urban areas; 14,150 tons were directed at aircraft factories; 10,600 tons at oil refineries; 4,708 at arsenals; 3,500 tons at miscellaneous industrial targets; 8,115 tons at air fields and sea-plane bases in support of the Okinawa operation; and 12,034 mines were sown.

Bombing altitudes after 9 March 1945 were lower, in both day and night attacks. Japanese opposition was not effective even at the lower altitudes, and the percentage of losses to enemy action declined as the number of attacking planes increased. Bomb loads increased and operating losses declined in part due to less strain on engines at lower altitudes. Bombing accuracy increased substantially, and averaged 35 to 40 percent within 1,000 feet of the aiming point in daylight attacks from 20,000 feet or lower.

Monthly tonnage dropped increased from 13,800 tons in March to 42,700 tons in July, and, with the activation of the Eighth Air Force on Okinawa, would have continued to increase thereafter to a planned figure of 115,000 tons per month, had the war not come to an end.

Three-quarters of the 6,740 tons of bombs dropped by carrier planes on the Japanese home islands were directed against airfields, warships, and miscellaneous military targets, and one-quarter against merchant shipping and other economic targets. Most of the warships sunk in home ports had already been immobilized for lack of fuel. The accuracy of low-level carrier plane attack was high, being at least 50 percent hits within 250 feet of the aiming point. The attack against the Hakodate-Aomori rail ferries in July 1945 sank or damaged all twelve of the ferries, 17 steel ships, and 149 smaller ships.

United States Strategic Bombing Survey: Summary Report (Pacific War)

I assume the 6,70 tons of bombs dropped by the USN on the Home Islands was around June/July? That the USAAF dropped 42,700 tons in July alone puts the amount of bombs dropped by the USN in perspective.

 

[XBe02Drvr]

Boys, boys, boys, are we letting our egos get the better of our wisdom here? Young and impetuous, or "mature" and well researched, do we really need to hurl personal insults? Why can't everybody count to ten then recheck their source data before replying to a post they disagree with? I came to this forum to learn, not to spectate at pissing contests and food fights. R E S P E C T! 'Nuf said.

 

[Zipper730]

FBJ,

No - if you were so smart your would have realized that the Japanese still had a huge deployed army in China and have indicated they were not going to surrender.

Wait, I was under the impression that the Japanese were extending feelers for surrender prior to the deployment of the nuclear bombs? I remember hearing statements from Admiral Leahy and General Eisenhower to this effect.

If you're going to rant about the cruel use of nukes like some revisionist, your time here will be short.

I'm not sure why people would regard the use of the nuclear weapons as so unusually cruel with the available knowledge: For most intents and purposes, a nuclear bombing does exactly what a high explosive and incendiary attack does -- it flattens lots of buildings and produces a firestorm with the end result being a whole lot of rubble and debris -- the big difference is that it does it way faster and with one bomb.

Since the attack was an airburst the long term exposure to radiation was actually fairly low: Short term the exposure was massive due to the fission reaction itself and some precip. While the knowledge that deaths would ensue from radiation was understood: I'm not entirely certain if was realized that the more ugly details such as birth defects was actually known at the time.

 

[FLYBOYJ]

FBJ,

Wait, I was under the impression that the Japanese were extending feelers for surrender prior to the deployment of the nuclear bombs? I remember hearing statements from Admiral Leahy and General Eisenhower to this effect.

They where, but this was not a unified attempt within the Japanese leadership and there were many who were totally against any kind of surrender.

Kyūjō incident - Wikipedia, the free encyclopedia

 

[Zipper730]

They where, but this was not a unified attempt within the Japanese leadership and there were many who were totally against any kind of surrender.

Kyūjō incident - Wikipedia, the free encyclopedia

True, but that occurred even with the use of nuclear weapons

 

[XBe02Drvr]

From what I've read, I don't think the American leadership (who didn't have a good understanding of the inner workings of the Japanese power structure) trusted the ability of the intermediaries to actually effect a cessation of hostilities. The die-hard fanatics were vocal and visible. MacArthur, an "Asia man" practically from birth, probably understood it best, but he was a field commander far from Washington. Witness the miracles he accomplished running the occupation.
The post-Hiroshima "revisionist" generation (myself included) are living in a different world and a different sensibility from what existed at the time. I can't imagine having the responsibility of sending a million and a half American boys into the teeth of ninety million men, women, and children armed with a death wish and everything from Kamikazes to pipe bombs, swords, scythes and kitchen knives. Hiroshima and Nagasaki, horrific as they were, pale by comparison.

 

[pinehilljoe]

USN Carrier based aircraft may not have been as effective as land based for Strategic Targets, but if the War had continued, I am sure we would have used every means possible. Any aircraft that could carry a bomb would have been used on Tactical and Strategic targets,

The Eighth was redeploying to the Far East, along with the Tiger Force.

 

[GrauGeist]

Here's a very good overview of the Allied operation during the final stages of the war, leading up to the end. It has the proposed invasion plans outlined, too.

It also covers the continuation of combat, as several overseas districts continued the fight even after Japan formally surrendered. I'd have to go back and look, but I believe the final cessation of hostilities were in mid September in Singapore.

It also covers Japanese forces overseas, by district complete with totals.

This is just Chapter 14, but at the bottom of the page, you have an option to go to the previous chapter or go to the table of contents, if you wish to read more.
Chapter 14: Japan's Surrender

 

[XBe02Drvr]

I don't think the USN were too keen on twins W, even their own F7F was delayed/revised/land-based.
( & don't forget they were 'dry ships' as far as glycol goes too, supposedly, even though P-51s were trialed)

Seems big singles such as the Boeing XF8B, Martin Mauler & Douglas Skyraider were more favoured.

Demonstrations with Mosquitoes, Venturas, et al to the contrary, operating such aircraft on carriers of the day on a routine basis just wouldn't have been practical. It wasn't until the 50s and 60s when angled decks, hydraulic arresting gear, steam catapults, and tricycle gear combined to make big twins on a carrier into a practical operation. And then they were designed-from-scratch Naval aircraft, not converted landlubbers. Now I know some of you will point to some of the first AJ1s and A3Ds operating from straight decks in the 50s. True enough, but that was never anything but a super hairy operation dictated by the need for a sea-going nuclear deterrent. With the accident rate to prove it!
BTW, did you know the AJ1 was actually a tri-motor? Besides the two wing mounted props, it had a jet engine in the tail.

 

[GrauGeist]

Demonstrations with Mosquitoes, Venturas, et al to the contrary, operating such aircraft on carriers of the day on a routine basis just wouldn't have been practical. It wasn't until the 50s and 60s when angled decks, hydraulic arresting gear, steam catapults, and tricycle gear combined to make big twins on a carrier into a practical operation. And then they were designed-from-scratch Naval aircraft, not converted landlubbers. Now I know some of you will point to some of the first AJ1s and A3Ds operating from straight decks in the 50s. True enough, but that was never anything but a super hairy operation dictated by the need for a sea-going nuclear deterrent. With the accident rate to prove it!
BTW, did you know the AJ1 was actually a tri-motor? Besides the two wing mounted props, it had a jet engine in the tail.

The USN was looking into a twin built along their guidelines prior to WWII, it was the XF5F (and the USAAC got involved and their version was the XP-50), they even looked into a navalized version of the P-39 (converted to a tail-dragger) and various versions of the P-51. None of those avenues panned out, however.

As it turns out, the short-lived XF5F project led to the F7F.

 

[XBe02Drvr]

And did the F7F ever turn out to be useful/practical as a carrier bird? Don't remember seeing any pix of it in that application.

 

[XBe02Drvr]

And as for Cobras, Mustangs, etc, landlubbers seldom convert gracefully to carrier ops. Different kind of regime, requires a different breed of bird.

 

[wuzak]

Demonstrations with Mosquitoes, Venturas, et al to the contrary, operating such aircraft on carriers of the day on a routine basis just wouldn't have been practical. It wasn't until the 50s and 60s when angled decks, hydraulic arresting gear, steam catapults, and tricycle gear combined to make big twins on a carrier into a practical operation. And then they were designed-from-scratch Naval aircraft, not converted landlubbers. Now I know some of you will point to some of the first AJ1s and A3Ds operating from straight decks in the 50s. True enough, but that was never anything but a super hairy operation dictated by the need for a sea-going nuclear deterrent. With the accident rate to prove it!
BTW, did you know the AJ1 was actually a tri-motor? Besides the two wing mounted props, it had a jet engine in the tail.

618 Squadron were to operate Mosquitoes from carriers.

Originally they were to use the Highball bomb against the Tirpitz, but that was changed to flying from carriers against the Japanese fleet, again with the Highball.

They were deployed to Australia in December 1944, but did not go into service and were disbanded in July 1945.

No. 618 Squadron RAF - Wikipedia, the free encyclopedia

Given that the Mosquito's wing span was the same as the Grumman TBF Avenger, that it was slightly longer and heavier it would not be beyond the imagination that the Mosquito could operate from a carrier. The main disadvantage was the size of teh Mosquito whem stowed, due to the twin engines, and the glycol coolant required to be stored on the ship.

But the RN carriers operated Sea Hurricanes and Seafires, so the last would not have been as much of an issue.

The Mosquito (B.IV) could carry a similar bomb load to the TBF but could carry it 50% further and ~100mph faster.

 

[stona]

In June 1945 the US Intelligence was reporting that.

"Japan might surrender at any time"

but that this depended on the terms of surrender and there was an understanding that the Japanese believed.

""that unconditional surrender would be the equivalent of national extinction, and there are as yet no indications that they are ready to accept such terms."

Since the defeat at Saipan and Tojo's resultant resignation the so called 'peace army' had been gaining influence in Japan. As early as September 1944 the Swedish Minister in Tokyo was approached unofficially (in the name of Prince Konoye?) to sound out Allied terms for peace. This approach and another in March came to nought, but it did establish that those advocating peace in Japan saw the demand for unconditional surrender as their biggest obstacle.

The Suzuki cabinet that came to power in April 1945 had an unspoken mandate from the Emperor to seek peace, but events moved fast. The Soviet Union announced that it would not renew the neutrality pact after April 1946 and then Germany surrendered in May. On June 3rd the Soviet Ambassador (Malik) in Tokyo was approached with a view to Soviet mediation in a peace process. Nothing came of this. At the end of June the Japanese government, through its Ambassador (Sato) in Moscow, asked the Soviet government to mediate directly in ending the war in the Far East. A series of signals between Moscow and Tokyo were intercepted and decoded by the Americans who therefore knew exactly what was going on. Once again unconditional surrender and terms which did not include preservation of the Imperial system were not acceptable to the Japanese. The Soviets in any case delayed until Stalin had left for Potsdam.The Japanese were desperate to surrender, but not on any terms.

It was in view of these accurate intelligence assessments by the Americans that the decision to use the atomic bomb was taken.

There were other factors, the US was worried about the future role and influence of its allies in the region (mainly Britain, but the USSR and France too) if the war dragged on and they became more committed.
The primary factors were an unwillingness to allow the war to drag on as Japan was strangled to death, as per the June plan agreed by the Chief's of Staff, an understandable unwillingness to undertake an invasion unless absolutely unavoidable, and what the Americans saw as Japanese intransigence in their unwillingness to acknowledge their defeat and accept an unconditional surrender.

What would you have done? The brave decision, not the easy one, was to drop the bomb(s) and I find it completely justified. It's easy to take the moral high ground seventy years later when blissfully unaware of the factors that forced the decision, not so easy when the facts are known. The facts never seem to bother some people

Cheers

Steve

 

[michaelmaltby]

And there was still a huge, undefeated, Japanese army in China that was largely unaffected by either the Communists or the Nationalist forces.

 

[stona]

& how was this huge army going to get back to Nippon? By sampan?
Do you imagine the USN/USAAF would allow that?

But they were relevant. The distaste for an invasion of the Japanese islands meant that serious consideration was given to a plan to encircle them and bomb and strangle them to death. This would have entailed seizing bases on the Chinese mainland and as MacArthur pointed out, the seizure of a ring of bases around Japan would disperse Allied forces even more than they already were, and (if an attempt was made to seize positions on the China coast) might very well lead to long-drawn-out operations on the Asiatic mainland. It was his objection to this plan that more or less forced the Chiefs of Staff to adopt the June 18th Plan for the final subjugation of Japan. It did not involve operations in China, but did involve the huge risk of two invasions. The salient points were.

1. Air bombardment and blockade of Japan from bases in Okinawa, Iwo Jima, the Marianas, and the Philippines.

2. Assault of Kyushu on 1 November 1945, and intensification of blockade and air bombardment.

3. Invasion of the industrial heart of Japan through the Tokyo Plain in central Honshu, tentative target date 1 March 1946.

This envisaged a continuation of the war, with all the expense in blood and treasure of almost another 12 months, if everything went according to plan.
Many at the June meetings knew that the atomic bomb was expected to be ready in a matter of months, some knew that a test was expected in the next four to five weeks.
I don't think it is difficult to see why the decision to drop the bomb(s) was taken, but that did not make it an easy decision to take.

Cheers

Steve

 

[michaelmaltby]

"... I don't think it is difficult to see why the decision to drop the bomb(s) was taken, but that did not make it an easy decision to take."

If there ever was a situation that warranted the use of such a weapon ... it was the preemption of invasion of the Homeland by the use of the bombs ... it saved the lives of both allies and Japanese, IMCO.

It was fortunate, in hindsight, that Truman came to office with absolutely no awareness of the Manhattan Project and had to evaluate the available tools with the forthcoming military obstacles in short order.

 

[stona]

If there ever was a situation that warranted the use of such a weapon ... it was the preemption of invasion of the Homeland by the use of the bombs ... it saved the lives of both allies and Japanese, IMCO.

It obviously saved Allied lives and the potential Japanese casualties as the islands were first isolated, conventionally bombed for another 9 months/a year (best case scenario) and then invaded would surely have been many times the number inflicted by the two atomic bombs.

With the benefit of hindsight the decision to use atomic weapons is even more of a 'no brainer' than it was at the time. There were many who had reservations about using the bombs, at least directly on Japanese cities, and some who didn't want to use them at all. Fortunately cooler heads prevailed.

Cheers

Steve

 

[Shinpachi]

Awesome logic and plan on the desk, Steve.
I frankly admire

 

[Shinpachi]

& how was this huge army going to get back to Nippon? By sampan?
Do you imagine the USN/USAAF would allow that?

Japanese army in China did not have to go back to Japan as they were deployed there to build up new Chinese Empire.
It was a simple story