How many US Aircraft Carriers were enough?

[SaparotRob]

I'm reading "The Ultimate Battle" by Bill Sloan on they are on the 9th wave and it does not seem anywhere near that many.

Per "The Last Great Battle of - Bloody Okinawa" by Wheelan:

"The Japanese fell short of their goal of "one plane one ship," but sank 36 American warships, and damaged 368 other vessels at Okinawa. The Navy's losses were the highest of the Pacific war: 4,907 sailors and officers killed, and 4,824 wounded. Japan lost an estimated 1,600 suicide and conventional planes at Okinawa."

Hit reply by error

 

[EwenS]

4,000+ Kamikazes lined up ready to go. Several hundred put a number of fleet carriers out of way during Okinawa.

For Operation Iceberg most of the air cover had to be delivered by carrier aviation due to the distances involved. As Okinawa is only 350 miles from southern Kyushu, the target area for Operation Olympic scheduled for 1 Nov 1945, far greater land based air power could be brought to bear, especially fighter cover, to augment a much larger force of CV/CVL/CVE than was assembled for Iceberg.

Okinawa would have provided a base for the 5th, 7th, 8th and 13th Air Forces plus 2 Marine Aircraft Wings and the first two squadrons of the RAF Tiger Force, plus 20th AF B-29s in the Marianas and 7th AF fighters on Iwo Jima.

As for the carrier groups themselves lessons had been learned. CAG compositions were being adjusted, CVLs would be fighter only but CVs with more SB2C, more radar picket destroyers with more SP fighter control radars and the first Project Cadillac AEW Avengers.

The downside was that the Japanese had worked out exactly which areas and beaches the landings would take place on.

Allied Order of Battle for Operation DOWNFALL

Project Cadillac

The most technologically-advanced response to the increasing kamikaze threat was the US Navy’s Project Cadillac, which included the development of the world’s first AEW (Airborne Early Warning) sys…

weaponsandwarfare.com

 

[SaparotRob]

Great link EwenS. Thanks.

 

[Thumpalumpacus]

To expand on @EwenS's link:

By May 1943, a range of 50nm between an aircraft carrying the radar set and the remote base station had been achieved. Progress was remarkably rapid considering the long list of new technologies involved.

A new radar, designated AN/APS-20, was developed. It operated in the S-band (10cm wavelength) with a theoretical range of 130nm to detect a single low-altitude aircraft. (The practical detection range for a single Overwater target, taking sea-surface backscatter into account, was 45nm. Larger formations could be reliably detected at 100nm.) The radar included integral IFF and automatic orientation of the PPI image to true north, so that relayed radar image would not be affected by the aircraft's heading. The base station could be any facility, such as a ship's CIC, equipped with the necessary receiving equipment and PPI displays within a 100nm range of the airborne radar.

To deploy this system on an aircraft carrier required an aircraft capable of carrying a rotating radar antenna 2.4m in diameter and 1040kg of equipment, still capable of launching from and trapping on existing Essex-class aircraft carriers. The only aircraft that could meet these requirements was the TBM Avenger. A TBM-3 was taken off the Eastern Aircraft assembly line and delivered to the Navy's Johnsville (PA) Air Development Center for modification. It emerged with the cockpit aft of the pilots seat faired over to make room for the radars electronics, stations for two operators in the aft fuselage, all armament and armor removed, small vertical fins added to the horizontal tail to aid directional stability and, most noticeably, a large faired radome hanging below the fuselage. The XTBM-3W, as this strange-looking aircraft was dubbed, first flew on 5 August 1944. Such was the urgency of this project that flight testing was hurriedly completed and an order for 27 addition conversions followed immediately. The first of these was delivered in March 1945 and successful carrier qualification trials were conducted on Ranger (CV 4) off San Diego between April and June. The plan was to have four-plane detachments deployed on Enterprise, Hornet (CV 12) and Bunker Hill in time to support the projected invasion of Kyushu, Operation Olympic, scheduled for 1 November. By extending the range at which kamikaze raids could be detected and the reliability with which they could be tracked, in particular low-altitude formations that could often elude sea-level radars until they were too close to intercept, these first AEW aircraft offered the best hope of blunting the anticipated kamikaze onslaught. An additional side-benefit, no doubt appreciated by every destroyerman in the US Navy, was the replacement of surface radar pickets with aircraft.

Stuff like this is why I read here. I had no idea AEW was introduced that early.

 

[GrauGeist]

Just the first invasion stage was impressive, Operation Olympic, slated for 1 November (X-Day) landing on Kyushu.
It would involve:
42 Aircraft Carriers
24 Battleships
400 Destroyers
14 U.S. Divisions (Army and Marines)

Also planned for deployment against Japanese strongholds, was the JB "Loon" (American version of the V-1) and the TDR-1, which was a TV controlled drone.

 

[Conslaw]

Just to complete the picture here is the US CVE build history.

The whole US CVE programme was kicked off by FDR in Oct 1940. After various discussions about the complexity of ship required, a C3 merchant hull was requisitioned in March 1941 to become AVG/ACV/CVE-1 Long Island on completion in June 1941.

There was then some discussions about converting 3 large transports as AVG-2 - 4 which came to nothing.

In early 1941 negotiations with Britain resulted in 6xC3 incomplete hulls being acquired by the USN for Lend Lease Lease to Britain. These became Archer, Avenger, Biter, Charger, Dasher and Tracker. Charger was reacquired by the USN in Oct 1941 principally, at that time, with the intention of assisting in training FAA pilots for the RN. The final ship, Tracker, became the model for the remaining C3 conversions.

The FY42 programme saw the requisitioning of 20 more C3 hulls then building which became the Bogue class. 10 were Lend Leased to the RN. These completed between Aug 1942 and June 1943.

Another 24 C3 conversions were ordered as part of the FY43 programme (some sources say FY42), starting May 1942. Initially these were to be split between the USN and RN, but eventually only 1 ship remained with the USN, Prince William completed April 1943. By that stage they were running out of C3 hulls in the merchant shipbuilding programmes to convert.

During 1942 the USN converted 4 of its precious Cimarron class fleet oilers to CVE in time for Operation Torch in Nov 1942. These became the Sangamon class. These proved better ships than the C3 conversions and led to the development of the final CVE class (see below).

The orders for CVE placed in 1942 need to be viewed against the background of the U-boat campaign then taking place against shipping on the US east coast and Caribbean, with large numbers of ships being sunk and no end in sight. At this time both the USN and the RN were placing orders for huge numbers of escort ships, just as many as the yards could cope with building. By late 1943 the position had changed dramatically but no one could foresee that in mid-1942. Late 1943 saw for example the cancellation of some 400 DE that had been ordered in 1942.

Then in June 1942 FDR intervened again and demanded another 50 CVE be built. This seems to have been prompted by an offer from Henry J Kaiser looking for work for one of his yards in Vancouver, Washington (not Canada). He had a CVE design prepared by Gibbs & Cox the Naval architects. This offer was accepted,and after some refinement the Casablanca class was born. 50 ships in FY43 (or FY42 in some sources) laid down between Nov 1942 and March 1944 and completed in the space of the year between July 1943 and July 1944. Initially these were to be split between the USN and RN, with at least 5 earmarked for the latter, but all ended up with the USN while the RN standardised with CVE based on the C3 hull.

By 1943 when the FY44 programme was being considered, attention turned to a better CVE based on the Sangamon class tanker hull. 15 Commencement Bay class were ordered with construction commencing in Sept 1943. 10 of these completed between Nov 1944 and the end of the war with the remainder by Feb 1946. Another 8 were ordered for FY45 of which 2 commissioned Dec1944/Jan 1945, another two completed but never commissioned and went straight to reserve before turning up in one of the Dirty Harry movies in the 1970s. The remaining 4 were suspended in Aug 1945 and subsequently scrapped on the slips.

In March 1945 FDR authorised another 12 but construction of these had not begun by the time the war ended so they were cancelled.

If Henry J Kaiser hadn't been able to make that offer to build 50 CVE in 1942 and make good on his mass production effort, then we might not have seen so many CVE.

A few years ago, I was in Vancouver Washington, and I visited the site of the shipyard where those CVEs were built. Of course, a lot of it isn't there anymore, but what strikes me is even now, that area is not very densely populated. I'm surprised they were able to find the manpower to build them with all the competing demands for labor. Maybe they ferried people from Portland, across the Columbia River.

 

[EwenS]

A few years ago, I was in Vancouver Washington, and I visited the site of the shipyard where those CVEs were built. Of course, a lot of it isn't there anymore, but what strikes me is even now, that area is not very densely populated. I'm surprised they were able to find the manpower to build them with all the competing demands for labor. Maybe they ferried people from Portland, across the Columbia River.

There was mass migration in the USA in WW2 to man all the shipyards and industrial plants. And many women joined the workforce. Have you heard of Rosie the Rivetter? This from just one site:-


Prosperity returned as the country mobilized for World War II. Eight months before the bombing of Pearl Harbor, the Tolan Committee investigating the migration of destitute citizens changed its name to the Committee on National Defense Migration. It went from a committee preventing people from migrating to one worried that not enough people would migrate to fill the jobs required by defense mobilization. Preparation for war generated a new wave of migration.

The South, with a glut of surplus labor, provided workers to the industrialized Midwest and an industrializing West. Most defense industries were located in the North and West, thus wasting a rare opportunity to change the course of southern social and economic life. The Willow Run bomber plant, constructed by Henry Ford near Detroit, attracted a flood of new laborers from other regions despite the urging of Office of Production Management to build defense plants in areas with labor surpluses, such as the South.

California became a magnet for regional migration. Historian James N. Gregory explains in American Exodus, "the effects were particularly stunning in California, which received more federal defense dollars than any other state, some ten percent of total war-era expenditures." All of those defense dollars attracted a mammoth migration of 621,000 people from Oklahoma, Arkansas, Texas, and Missouri that dwarfed the number of people who left these states during the 1930s Dust Bowl, an ecological disaster that ruined agriculture. And increasing numbers of African Americans from the South gave California its first significant black population.

In addition you had skilled workers encouraged to move to new plants to allow their experience to be spread amongst the unskilled recruits.

 

[pinehilljoe]

When it came to the wartime shipbuilding programmes such as the Maximum Effort Programme of 1942, orders were being placed for as many ships of each type as possible up to the capacity that each yard could take. At the same time yards tended to specialise in particular types of ship. So in 1940 2 Cleveland class cruisers ordered from Federal in New Jersey were cancelled to allow that yard to concentrate on producing destroyers, with new cruiser orders being placed elsewhere.

Priorities also changed as the war went on. Bethlehem Quincy for example got 8 Baltimore class cruiser orders in 1940, and laid down 4 in 1941. Then carriers took priority so the next 4 weren't laid down until 1943, by which time it was clear more 8" cruisers were needed following losses in the Solomons in late 1942. More orders were then placed for these in other yards as well. But these ships only began to enter service in 1945.

When it comes to large warships, cruiser sized and above, FDR seems to have been very careful about building for the current war not the next. Hence his opposition to the Midway class. But US industry achieved some remarkable feats in reducing shipbuilding times. An Essex in 2 years instead of 3 for example.

1942 the urgency was for DE for the U-boat campaign. In late 1943 with the Allies beating the U-boat some 400 DE were cancelled. 1943 saw a vast increase in assault shipping construction for D-Day and the Pacific campaigns.

Every effort was made to maximise the use of building facilities. At Philadelphia Navy Yard they built 2 Baltimore class cruisers simultaneously from 1943 in a single dry dock intended for a cancelled Montana class battleship. Both were floated out the same day but their final completion dates were 6 months apart in Jan & July 1945.

In terms of fast carrier group organisation from late 1943 onwards each task group would consist of 3-5 carriers (numbers grew in each group as new carriers completed) with an escort of 2-3 fast Battleships, a cruiser division of 4 ships, generally of the same class, an Atlanta class AA cruiser and approx 16 destroyers. These usually comprised the most modern units available. So as the war went on Sumner and eventually Gearing class destroyers supplemented and then displaced less modern Fletcher class ships. There were exceptions. At one point (Marianas of Leyte I cant remember which) the fast Battleships were concentrated in a single task group separate from all the carriers. And in spring 1945 there was a separate night carrier group for a short time with just 2 carriers, and a few cruisers and destroyers for escort.

For Operation Olympic, the invasion of Kyushu, Japan in Nov 1945 the USN would have fielded Enterprise plus 14 Essex class and 7 CVL in 5 TG divided between the 3rd and 5th Fleets. To that would have been added 4 or 5 fleet and 4 light fleet carriers from the British Pacific Fleet in two TG. Plus all the escorts and support ships.

Very informative post. Much of the post is corroborated by Conways All the Worlds Fighting Ships 22-42, and Clarke Reynold's "The Fast Carriers".

If the War had continued to 1946, the Pacific Fleet would be so large that TF-38 and T-58 would both be at Sea, 38 flagged by ADM Towers, 58 flagged by ADM Sherman.

 

[EwenS]

Very informative post. Much of the post is corroborated by Conways All the Worlds Fighting Ships 22-42, and Clarke Reynold's "The Fast Carriers".

If the War had continued to 1946, the Pacific Fleet would be so large that TF-38 and T-58 would both be at Sea, 38 flagged by ADM Towers, 58 flagged by ADM Sherman.

It wouldn't have taken until 1946. It was planned for Operation Olympic scheduled for Nov 1945.

 

[GrauGeist]

Operation Coronet was planned for 1 March 1946, landing in the area near Tokyo, assuming that Operation Olympic was successful in securing the southern areas of Kyushu as well as key areas on the Asian mainland.
Coronet was planned to have both US and British assets involved.

 

[SaparotRob]

A "what-if". I have read some of the details of Operation Downfall. All the forces to attack Kyushu. All the defenses of Kyushu. What if the Allies skipped Kyushu and went straight to Honshu? Sort of like the landings at Normandy being just a feint when the real invasion will be at Calais. Japan would not be able to redeploy easily. I know there would logistical complications and Kyushu out of range of land based aircraft from Okinawa. I was thinking of "Island hopping" on a grander scale since Kyushu seemed to have so much dug in force.
I am very thankful that this invasion wasn't necessary.

 

[EwenS]

Operation Coronet was planned for 1 March 1946, landing in the area near Tokyo, assuming that Operation Olympic was successful in securing the southern areas of Kyushu as well as key areas on the Asian mainland.
Coronet was planned to have both US and British assets involved.

Operation Olympic would also have involved "British assets".

The British Pacific Fleet would have provided 2 carrier groups as part of the Third Fleet. 8 or 9 CV/CVL (depending on refit program) plus supporting Battleships, cruisers and destroyers supported by their own fleet train. It would have included ships manned by Australians, Canadians and New Zealander. You can get a feel for the composition of the BPF in Aug 1945 here -

BPF Warships.htm

In addition the first elements of the heavy bomber Tiger Force would have arrived on Okinawa. The Airfield Construction Service units earmarked to build their airfields arrived at Eniwetok just as the war was ending in Aug. The "Special Missions Wing" consisting of 9 and 617 squadrons with their 12,000lb Tallboy bombs and some 40 Lancasters were scheduled to deploy in late Sept 1945. With the end of the war the ACS units were diverted to aid the reoccupation of Hong Kong from the end of Aug 1945.

By the time of Operation Coronet the BPF would have expanded further. Tiger Force would also have grown, plans being for 20 Lancaster squadrons, a pathfinder Mosquito squadron and a Mosquito recce squadron plus supporting transport and Air Sea Rescue units.

A Commonwealth Corps of 3 army divisions was planned for Coronet, initially as a floating reserve. The 6th Canadian Div was being reorganised and equipped in Canada when the war ended. They would have been joined in Canada by the 3rd British Div in late 1945. In addition Australia was to raise a new division, the 10th, from units taken from existing divisions. The US insisted that all be armed with US weapons and organised on US lines to simplify logistics. They would probably have been landed from RN landing ships and craft. Britain had been lobbying for a greater ground element for Coronet but this was rejected by the US. MacArthur specifically rejected any involvement of Indian troops.

 

[GrauGeist]

Southern Kyushu had air bases that were used by the Japanese to reach Iwo Jima and Okinawa. Taking the southern portion of Kyushu would eliminate the Japanese from reaching vital Allied foreward bases on Iwo and Okinawa as well as provide airfields for Allied operations pushing northward.

The Japanese homeland has few coastal areas suitable for beach landings and they had each of those locations well defended both in manpower and emplacements.

If you get a chance, look up Operation Ketsugo (Ketsu-Go). This was Imperial Japan's defense strategy to oppose the impending Allied landings and invasion.

 

[EwenS]

A "what-if". I have read some of the details of Operation Downfall. All the forces to attack Kyushu. All the defenses of Kyushu. What if the Allies skipped Kyushu and went straight to Honshu? Sort of like the landings at Normandy being just a feint when the real invasion will be at Calais. Japan would not be able to redeploy easily. I know there would logistical complications and Kyushu out of range of land based aircraft from Okinawa. I was thinking of "Island hopping" on a grander scale since Kyushu seemed to have so much dug in force.
I am very thankful that this invasion wasn't necessary.

Firstly, the Japanese had substantial forces on Honshu in Aug 1945, and were mobilising others, which would have avoided the need to try to redeploy troops from Kyushu. Map here of their dispositions.

https://history.army.mil/books/wwii/MacArthur%20Reports/MacArthur%20V1/Images/p_125.jpg

Coronet was going to be a much larger operation than Olympic, 25 divisions landed in the first 30 days, with major elements deploying from the US west coast direct to the landing zone as well as from bases in the Philippines and around the Pacific. The landings were fully expected to be hard fought. US air power was vital to success. The whole point of seizing southern Kyushu (not the whole island) was to provide air bases to cover Coronet. Without those bases then the whole landing would need to be covered by the carriers of Third and Fifth Fleets until sufficient space could be obtained to allow construction of airfields. That would only have been on the same scale as planned for Olympic plus of course from Iwo Jima. But the airfields there were pretty much at max range for the P-47N and P-51D fighters deployed there, and there was little or no space to deploy more.

Normandy provides a good example of what could be achieved in Airfield construction. But the earliest strips there were for emergency landings, then rearming and refuelling with aircraft returning to England at night and after that for basing units as space increased. One problem in Japan is that much of the territory consisted of rice paddy fields with banks around them making Airfield construction more difficult.

Amongst the units planned for deployment were 2 Armoured divisions. These redeployed from Europe to the US in July / Aug 1945. By the time leave was given, and they were trained in amphibious techniques and re-equipped there is no way they would be ready in Nov 1945. Plans called for all the Armoured units to be equipped with a mix of M24 Pershing, M4 Sherman and M24 Chaffee. Mass production of M24 Pershing was only beginning to ramp up in summer 1945.

There were also plans for an artificial harbour for Coronet just like the Mulberries off Normandy. This was seen as essential to the logistic support of forces ashore. Problem is construction of the various elements was only beginning on the US west coast as a rush program as the war ended. No way would it have been ready by Nov 1945.

A good starting point to the plans is here

Chapter 13: "DOWNFALL"- The Plan for the Invasion of Japan

I'd also recommend this book.
Amazon product ASIN 1591143160
View: https://www.amazon.co.uk/dp/1591143160/

 

[SaparotRob]

Firstly, the Japanese had substantial forces on Honshu in Aug 1945, and were mobilising others, which would have avoided the need to try to redeploy troops from Kyushu. Map here of their dispositions.

https://history.army.mil/books/wwii/MacArthur%20Reports/MacArthur%20V1/Images/p_125.jpg

Coronet was going to be a much larger operation than Olympic, 25 divisions landed in the first 30 days, with major elements deploying from the US west coast direct to the landing zone as well as from bases in the Philippines and around the Pacific. The landings were fully expected to be hard fought. US air power was vital to success. The whole point of seizing southern Kyushu (not the whole island) was to provide air bases to cover Coronet. Without those bases then the whole landing would need to be covered by the carriers of Third and Fifth Fleets until sufficient space could be obtained to allow construction of airfields. That would only have been on the same scale as planned for Olympic plus of course from Iwo Jima. But the airfields there were pretty much at max range for the P-47N and P-51D fighters deployed there, and there was little or no space to deploy more.

Normandy provides a good example of what could be achieved in Airfield construction. But the earliest strips there were for emergency landings, then rearming and refuelling with aircraft returning to England at night and after that for basing units as space increased. One problem in Japan is that much of the territory consisted of rice paddy fields with banks around them making Airfield construction more difficult.

Amongst the units planned for deployment were 2 Armoured divisions. These redeployed from Europe to the US in July / Aug 1945. By the time leave was given, and they were trained in amphibious techniques and re-equipped there is no way they would be ready in Nov 1945. Plans called for all the Armoured units to be equipped with a mix of M24 Pershing, M4 Sherman and M24 Chaffee. Mass production of M24 Pershing was only beginning to ramp up in summer 1945.

There were also plans for an artificial harbour for Coronet just like the Mulberries off Normandy. This was seen as essential to the logistic support of forces ashore. Problem is construction of the various elements was only beginning on the US west coast as a rush program as the war ended. No way would it have been ready by Nov 1945.

A good starting point to the plans is here

Chapter 13: "DOWNFALL"- The Plan for the Invasion of Japan

I'd also recommend this book.
Amazon product ASIN 1591143160
View: https://www.amazon.co.uk/dp/1591143160/

Well, so much for my cunning plan.

 

[pinehilljoe]

Very informative post. Much of the post is corroborated by Conways All the Worlds Fighting Ships 22-42, and Clarke Reynold's "The Fast Carriers".

If the War had continued to 1946, the Pacific Fleet would be so large that TF-38 and T-58 would both be at Sea, 38 flagged by ADM Towers, 58 flagged by ADM Sherman.

you're correct, I'm on travel and don't have my copy of Fast Carrier to check. ADM Towers, one of the pioneers of Naval Aviation, finally got a major Sea Command when the War ended.

 

[Greg Boeser]

There was mass migration in the USA in WW2 to man all the shipyards and industrial plants. And many women joined the workforce. Have you heard of Rosie the Rivetter? This from just one site:-


Prosperity returned as the country mobilized for World War II. Eight months before the bombing of Pearl Harbor, the Tolan Committee investigating the migration of destitute citizens changed its name to the Committee on National Defense Migration. It went from a committee preventing people from migrating to one worried that not enough people would migrate to fill the jobs required by defense mobilization. Preparation for war generated a new wave of migration.

The South, with a glut of surplus labor, provided workers to the industrialized Midwest and an industrializing West. Most defense industries were located in the North and West, thus wasting a rare opportunity to change the course of southern social and economic life. The Willow Run bomber plant, constructed by Henry Ford near Detroit, attracted a flood of new laborers from other regions despite the urging of Office of Production Management to build defense plants in areas with labor surpluses, such as the South.

California became a magnet for regional migration. Historian James N. Gregory explains in American Exodus, "the effects were particularly stunning in California, which received more federal defense dollars than any other state, some ten percent of total war-era expenditures." All of those defense dollars attracted a mammoth migration of 621,000 people from Oklahoma, Arkansas, Texas, and Missouri that dwarfed the number of people who left these states during the 1930s Dust Bowl, an ecological disaster that ruined agriculture. And increasing numbers of African Americans from the South gave California its first significant black population.

In addition you had skilled workers encouraged to move to new plants to allow their experience to be spread amongst the unskilled recruits.

Yup. My wife's grandmother moved to the West Coast to help build Liberty ships for the duration of the war.

 

[pinehilljoe]

One of the most famous photos of the War, I'd surrender!

 

[SaparotRob]

And that ain't all of 'em either.