Yamato, where could it have done the most damage?

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Carl Schwamberger
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Re: Yamato, where could it have done the most damage?

#16

Post by Carl Schwamberger » 19 Dec 2016, 03:04

Mil-tech Bard wrote:I would suggest that the Yamato surface action group that was being sent to Biak, ...

...A sound IJN naval victory at Biak would have made a Leyte landing...problematic.
Interesting proposal. At that date any cancellation or postphonement ofa Phillipines campaign would not have diverted resources anywhere else to make much of a stratigic gain for the US anywhere else.

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Re: Yamato, where could it have done the most damage?

#17

Post by Mil-tech Bard » 19 Dec 2016, 20:42

Carl,

If MacArthur had lost his light cruiser squadron, halk his escorts and a regimental combat team worth of sea lift to the Yamato. Exactly how willing would he have been to jump to Leyte in lieu of Mindanao?

You are looking at a 1-to-3 month delay of landings west of Biak.

So when Halsey said the Japanese were weak at Leyte from his carrier raids, MacArthur would have been farther away in terms of land based air power than he was in out time line.

Mindanao would have looked much better than Leyte under those circumstances.


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Re: Yamato, where could it have done the most damage?

#18

Post by Kingfish » 19 Dec 2016, 21:03

Carl Schwamberger wrote:
Kingfish wrote:Unless I am mistaken, the only time the IJN ran a TF to Guadacanal for the express purpose of surface engagement was the battle of Savo Island. All the others were for other tasks, and whatever naval battles occurred were the result of coincidence that both sides had SAGS in the vicinity.

That is why I don't see the IJN sending Yamato down the slot.
In most of those cases the Japanese did prudently expect the USN to attempt to intervene. There were aspects to those battles that were a suprise to the Japanese, but they did not dismiss the posibility surface actions could occur & planned their actions on that contingent. In all five surface action off Guadalcanal both sides had intel of possible enemy SAGS near & a fair idea of the logical enemy intent. The battles were the result of good and bad planning by each side & not random encounters.
They were random in terms of timing. Both sides certainly went into Ironbottom sound expecting action, but as you pointed out there were only 5 encounters when the two locked horns.
The gods do not deduct from a man's allotted span the hours spent in fishing.
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Re: Yamato, where could it have done the most damage?

#19

Post by Carl Schwamberger » 01 May 2017, 19:41

Mil-tech Bard wrote:Carl,

If MacArthur had lost his light cruiser squadron, halk his escorts and a regimental combat team worth of sea lift to the Yamato. Exactly how willing would he have been to jump to Leyte in lieu of Mindanao?

You are looking at a 1-to-3 month delay of landings west of Biak.

So when Halsey said the Japanese were weak at Leyte from his carrier raids, MacArthur would have been farther away in terms of land based air power than he was in out time line.

Mindanao would have looked much better than Leyte under those circumstances.
Was there that much stratigic gain in defeating Japan from the PI operations? There was the paralle campaign to Okinawa, the massacre of the Japanese cargo shipping was far along, & the air raids from the Marinas around the corner. Running two paralle Pacific offensives was useful insurance in 1943/44. but at this point a set back in PI does not alter Japans stratigic situation in any significant way. Even from the PoV of the moment it does not look that way.

Scattering the amphib fleet & sinking for US ships in the Leyte Gulf looks more like a operational victory, but I cant see it setting back Japans surrender in any notable way.

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Re: Yamato, where could it have done the most damage?

#20

Post by Carl Schwamberger » 01 May 2017, 19:57

Kingfish wrote:
Carl Schwamberger wrote:
Kingfish wrote:Unless I am mistaken, the only time the IJN ran a TF to Guadacanal for the express purpose of surface engagement was the battle of Savo Island. All the others were for other tasks, and whatever naval battles occurred were the result of coincidence that both sides had SAGS in the vicinity.

That is why I don't see the IJN sending Yamato down the slot.
In most of those cases the Japanese did prudently expect the USN to attempt to intervene. There were aspects to those battles that were a suprise to the Japanese, but they did not dismiss the posibility surface actions could occur & planned their actions on that contingent. In all five surface action off Guadalcanal both sides had intel of possible enemy SAGS near & a fair idea of the logical enemy intent. The battles were the result of good and bad planning by each side & not random encounters.
They were random in terms of timing. Both sides certainly went into Ironbottom sound expecting action, but as you pointed out there were only 5 encounters when the two locked horns.
The first the Savo island battle was deliberate as the Japanese objective was to inerdict the invasion force & the USN object to defend it. The Japanese knew there was a amphib fleet in the sound & the USN leaders felt the the odds were in favor of a enemy attack.

The second, third and fourth battles were as deliberate as can be, the USN set out to interdict the bombardment force, & the supply group if possible. In all three cases they did interdict the bombardment force. The Japanese suspected there would be a US effort to intercept & were prepared for exactly that. They had some indication from their radio traffic analysis the USN surface forces were 'active'. I cant recall if they had any air or sub scout reports of the US warships being at sea.

The fifth surface battle, Tassafaronga, may have been a random encounter. I dont know enough details.

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Re: Yamato, where could it have done the most damage?

#21

Post by Mil-tech Bard » 03 May 2017, 04:33

Carl Schwamberger

The logistical bases set up in the Philippines were absolutely vital to the two Operation Downfall invasions. And the decision to make those Operation Downfall logistical bases goes back to the 1944 Philippines base (FILBAS) agreement.

Page 304 of WASHINGTON COMMAND POST: THE OPERATION DIVISION lays out the various Pacific command conferences of
WW2. There were two Washington DC theater commander -- JCS conferences in March 1943 and Feb-Mar 1944 and four Joint Theater
Commander conferences in the Pacific:

Pearl Harbor - Jan 1944
Hollandia - Nov 1944
Guam - Feb 1945
Manila - July 1945.

When you cross reference WASHINGTON COMMAND POST with Coakley and Leighton's GLOBAL LOGISTICS AND STRATEGY 1943-1945 to find out what the subjects of these conferences were about, since all high level military strategy is logistical in nature. Chapter XXIII showed the Nov 1944 conference at Hollandia was primarily about the coming Luzon campaign and it hammered out the "FILBAS" Agreement (See page 566).

The agreement had the following points:
o MacArthur would support the XXIV Corps staging to Okinawa from
Leyte

o The Navy abandoned an earlier promise to crew US Army small
coastal freighters, the Coast Guard would instead

o MacArthur would create the logistical infrastructure to stage nine
POA Infantry/Marine divisions for future operations against the China
coast

o Nimitz gave up any further claim to US Army service units in the
closed out South Pacific theater
Of those points, only the first two were carried out in full. Mac could never get his shipping squared away in time for Navy needs for the larger Formosa operation that Iwo Jima and Okinawa later replaced. So Nimitz started requesting the Army South Pacific service units again.

However, when you look at the logistical staging for Operation Olympic, you realize a couple of things. First, MacArthur never stopped trying to fulfill the FILBAS logistical objectives. There were exactly nine infantry divisions staging from the Philippines for Operation Olympic.

Second, two of those Olympic divisions were being staged from the Southern Philippines.

This fact wasn't just a matter of "that is just where they were they were" after MacArthur went haring off after liberating Filipinos.

There were hard logistical limits on both the port capacity of Manila after Japanese destruction of facilities there in Feb-Mar 1945 and what could go over the beach and small ports of Leyte.

In addition, the limits of even world class port clearance facilities of the time made ships of more than 6,000 tons and more than four cargo holds "problematic" in terms of rapidly unloading cargo via cranes and cargo nets. It was not until the ISO container revolution that you got the expansion of cargo ships to the Midway class carrier sizes we see today.

The two divisions to be staged from the Southern Philippines for Olympic had to be staged from there because that is where the port capacity was, and all the islands in between needed to captured to allow unimpeded sea movement for MacArthur's small freighters, impressed Aussie fishing smacks and tug-barge shipments to those ports prior to that staging.

The Southern Philippines campaign never made it to the JCS level for reappraisal after Luzon. It happened because Nimitz's sign off for it in Nov 1944 FILBAS agreement.

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Re: Yamato, where could it have done the most damage?

#22

Post by Takao » 04 May 2017, 00:46

Carl Schwamberger wrote: The fifth surface battle, Tassafaronga, may have been a random encounter. I dont know enough details.
Tassafaronga was a planned encounter. The US Navy knew the Japanese were carrying out a reinforcement/resupply mission, knew an approximation of the Japanese force, and specified that the Japanese landing would be about 2300hrs of Tassafarong(this was later modified that the Japanese might arrive earlier than 2300hrs).

The Operations Plan and some AARs of the battle can be found here:
http://destroyerhistory.org/actions/ind ... 0&pid=4287

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Re: Yamato, where could it have done the most damage?

#23

Post by Mil-tech Bard » 05 May 2017, 01:37

Carl Schwamberger,

The Philippines happened as they did because Formosa was too close to Japanese land based airpower and too far from American land based airpower.

See the photo of the planned land based air coverage for an invasion of Formosa without taking Leyte and Luzon from Nimitz's Causeway Joint Staff Study attached.
Attachments
Page 67 from CAUSEWAY,JOINT STAFF STUDY -- Jun 1944 -- a606376.jpg
Planned land based air coverage for Causeway-Formosa Invasion Operation

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Re: Yamato, where could it have done the most damage?

#24

Post by Carl Schwamberger » 14 May 2017, 23:53

Mil-tech Bard wrote:Carl Schwamberger

The logistical bases set up in the Philippines were absolutely vital to the two Operation Downfall invasions. And the decision to make those Operation Downfall logistical bases goes back to the 1944 Philippines base (FILBAS) agreement.

...
Ok, so at this point the plans, and the preparations so far as they were along, were assuming the use of the Phillipines as a base for Op DOWNFALL. Does "vital" in this mean Op Downfall cannot be supported at all, or mean extensive and expensive alteration of preparations, or something else I am missing?

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Re: Yamato, where could it have done the most damage?

#25

Post by Mil-tech Bard » 30 Jul 2017, 15:40

Carl,

Sorry to take so long in getting back to you.

First, see the following conclusion from 'History of Planning Division, ASF. Volume 5" -- Labeled 1802.pdf in the Combined Arms Research Library - Digital Library -- which was the March 1944 War Department Strategic Planning Division evaluation of the Formosa operation in terms of losses it would incure.
LOGISTIC STUDY OF A PLAN FOR INVASION OF FORMOSA

CONCLUSIONS:
The foregoing logistic plan is, from a mechanical standpoint, adequate to support the operation. From a practical logistic standpoint, assuming the operation to be tactically sound, the plan is one of great hazard involving an extended line of communication for the assault and follow-up troops and their subsequent maintenance. The extreme distances from the staging and base areas require that the assault forces be mounted in APAs and AKAs. Although LSTs are capable, of accomplishing the trip, their low speed of 8-9 knots, compared with the 15 knot normal capability of the fast convoys, would seriously prejudice the safety of the fleet, the convoy, and its immediate escort. A damaged vessel will be a loss, because when crippled it would be inexpedient to escort it back to a distant base. To convoy it will dissipate the strength of the escort assigned to the convoy, and the reduced speed would hazard the loss of the escorts for the individually convoyed ships. In addition an APA is capable of carrying only 26 LCVPs and 3 LCM (3)s. An AKA can carry 16 LCVPs and 8 LCM (3). LST's would not be available. Therefore the assault against the formidable objective of FORMOSA would be mounted under serious handicap and might well prejudice the operation. A defeat would entail enormous losses
which would be extremely expensive in personnel, materials, time, and the support of public confidence. A loss in the amount of 30 APA's and 12 AKA's would delay further operations in the Pacific a minimum of twelve months. The replacement of combat loaders is the criterion.
NB: Admiral King lost the "Formosa versus Luzon" Debate in March 1944 and it took until September 1944 for him to give up the idea. The War Deprtment would not support an invasion of Formosa unless Luzon was captured first. And if Luzon was captured first, what was the point of invading Formosa.

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Re: Yamato, where could it have done the most damage?

#26

Post by Mil-tech Bard » 30 Jul 2017, 16:03

>> Does "vital" in this mean Op Downfall cannot be supported at all, or mean extensive and expensive alteration of preparations, or something else I am missing?

Short form Yes, the Philippines were vital. Without Formosa, somewhere had to be the logistical node between the West Coast of the USA and Japan to stage combat forces to invade the Japanese home Islands

See these definitions from "History of Planning Division, ASF. Volume 5 -- 1799"

Staged Division Manpower slice -- 25,000
Assault Division Manpower slice - 40,000

Directly quoted passages defining ASF project for Philippines base development in another volume of History of Planning Division, ASF --
1. "Logistic Study for Projected Operations, ASF-P-SL-5,11 informally furnished to technical service representatives on 23 February 1945, is one of a series on operations in the Pacific and deals with the maximum base development of the Philippines. This study will serve as a basis for preparation of War Department projects and for development of troop and other personnel requirements for service installations.
and projects to provide emergency resupply on Luzon for Olympic and Coronet.
d. Emergency supply for KYUSHU and HONSHU operations.

After forces have been mounted in the PHILIPPINES for the
operations against KYUSHU and HONSHU, supply will be from
the UNITED STATES with emergency supply only from LUZON.

On LUZON, a 30-day emergency stock of all classes of supplies will be maintained as follows:

For 13 divisions at 40,000 men from D+10 to D+90 of
KYUSHU operation (see ASF-P-SL-2). Supplies available for
KYUSHU operation.

For 25 divisions at 40,000 men from D+0 to D+150 of
HONSHU operation (see ASF-P-SL-1). Supplies available for
HONSHU operation. Second priority KYUSHU operation.

When you go look up "Project ASF-P-SL-1" in "History of Planning Division, ASF" you find in addition to coronet, there were three to four further nine division operations to complete the conquest of the Japanese Home Islands in the Summer and Fall 1946 plus a 25 division expeditionary force to China in the Fall-Winter 1946 to complete the extermination of the Japanese armies in China.

These planned for operations are where General Marshall et all talk about 1,000,000 American casualties from a conquest of Japan.

Assuming four each nine Division assaults -- Hokkaido, Northern and Southern Honshu, plus Shokaku -- That is 27 divisions at 35% casualties...Plus 25-35 more Divisions in China operations...

35% of a 20K combat element division slice is 7,000 casualties.

7,000 times 62 divisional assaults = 434,000 casualties.

All AFTER Coronet.

I'd say General Marshall's figures were well documented. And his "Atomic Diplomacy" academic critics are idiots.

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