M26 Pershing vs Japan

[ChristopherPerrien]

[

What I am looking at here is the shipping time lines for priority fast merchant ships.

The 10th Army asked for more tanks in mid- May 1945 and got 12 Pershings from the "Zone of the Interior" -- AKA the USA -- by Mid-June 1945. That was 30-45 days. The Pershings were landed by LCT coming from Hawaii.

The 10th Army also asked for the CDL's as soon as they knew they existed from Ordnance (Let's call that mid-May 1945) and per Hunnicutt, they arrived between late-June 1945 and VJ-Day from Depots in England. That means 45 days to 90ish days. More likely it is the latter than the former.

The ability of fast merchant ships operating outside of convoys from Europe and the West Coast to get to Hawaii, or from England to the East Coast by train to the West Coast and then by ship to Hawaii, means some really big things in terms of American 1945 logistical capability.

No convoys in the Atlantic, Indian Ocean and South Pacific is a huge increase in Allied shipping capacity, especially faster long distance shipping capacity.

While I understand you are using these issues to build a scenario for an Coronet, I think you are looking too hard at some numbers and not everything (logistical) that would have been entailed by introducing large numbers of new or novel weapon systems. You need trained tankers, mechanics, spare parts , etc.,organization, to provide support for these M26's and CDl's. No matter that America had the shipping capacity to move whatever amount of M26's(1,000's?) in mere days by mid 1945; The time in creating the necessary logistical tail to support them is worth giving more thought to, as to an accurate ATL/ What-if, besides just the numbers of tanks,ships and shipping times.

[binder001]

As far as logistical support to the CDL, don't forget that the US Army had deployed six battalions of CDLs to the ETO along with two Armored Group headquarters. Even though they didn't see massed combat, there was a fund of CDL knowledge in these men. Some would likely would have been moved from Europe to the Pacific. On a similar vein, the M26 was new but not truly new technology. The GAF engine in the M26 was a derivative of the Ford GAA that had been powering the M4A3 mediums. The 90mm gun had been in use with TD units since mid-1944. By the end of the war in Europe about 200 of the 300 M26s in the ETO had been issued to the troops, so again the Army was gaining experience with the type. So the Army did have a handle on the logistics and training requirements for the M26 and the CDL.

[Carl Schwamberger]

No refrence handy here, but I recall the CDL battalions designated for the Pacific were being refilled' with men from the CDL battalions in the ETO. That was a common practice in the summer of 1945, to strip the best officers & NCOs/technicians from the European units and send them to the PTO either in reorganized battalions or as veteran fillers for battalions still in the US. From veterans of the ETO of 1945 I've both read and heard first hand descriptions of the Army shaking out three or four battalions or aircraft squadrons to make up manpower for one to be sent to the Pacific.

[Mil-tech Bard]

There were 125 M26 Pershings scheduled in the plans for Olympic/Majestic. Three M26 companies out of Hawaii and four out of Luzon. So there was enough logistical support for those Pershings as a minimum. And as other had pointed out, they were using the same engine, transmission and tracks as a M4A3(HVSS) Sherman.

There were enough CDL tanks on Okinawa at the close of the war to put a CDL platoon on each major landing beach head.

The CDL was based on the M3 Grant and had the same engine, transmission and tracks as a M4 or M4A1. Which made up something like half of the US Army tanks on Okinawa and the Philippines.

The real issue for wargaming the Operation Olympic/Majestic landings is that they would not have happened on the planned date (01 Nov 1945).

First there was the Oct 1945 typhoon that hit Okinawa that would have damaged a large portion of the supplies and LCI/LSM/LST landing ships needed for the Kyushu landings.

MacArthur thought it would take 30 to 45 days to make up those losses. That puts the landings in Early to mid-December 1945.

Next, there is the issue of the Japanese high command issuing orders to start killing Allied POWs, civilian internees and civilians in occupied areas when the British "Operation Zipper" landings happened in Malaya on Sept 9th 1945, See:

Tennozan: The Battle of Okinawa and the Atomic Bomb by George Feifer, states at page 573:

"After the fall of Okinawa, Field Marshal Count Hisaichi Terauchi issued an order directing his prison camp officers to kill all their captives the moment the enemy entered his southeast Asia theater. That would have been when those 200,000 British landed to retake Singapore, less than three weeks after the Japanese surrender. There was a real chance that Terauchi's order would have been carried out, in case up to 400,000 people would have been massacred."

The American high command knew of these orders from code breaking, see:

http://www.strategypage.com/htmw/htmurp ... 00812.aspx

At the end of the war, before the atomic bombs were dropped, the Japanese high command sent orders to all commanders of prisoner of war camps to be prepared to kill all their prisoners on short notice, especially if enemy forces were nearby. The Allies became aware of this order, and when the Japanese finally agreed to surrender, the Japanese were told to rescind the "kill all prisoners" order, or else.

MacArthur had told his 8th Army commander General Eichenberger in April 1945 to prepare contingency plans for invading Java if the US Navy won the "Blockade or Invasion" show down in June 1945. He still had "Oboe Six" -- the invasion of Java -- in his back pocket when Adms Nimitz and King were set to re-opened the question of invasion in late August - early September 1945 as they were planning too when the A-bomb ended the war in August.

Based on what I have read, I think General Eichenberger could have gotten a Division sized task force from Mindanao to Java, with about two weeks supplies, in about two to three weeks once word that the Japanese were systematically killing Allied POWs and internees. The transports rolling up MacArthur's SWPA bases south of Mindanao would have been available and there was an Amphibian engineer Brigade that dropped off Australians in Borneo.

Eighth Army was going to be Operation Coronet's troops basis. So is was available for operations before then. But the Amphibian Engineer boat brigade he might have used for it was scheduled for Olympic/Majestic.

Once General Eichenberger's troops over ran murdered Dutch and Javanese civilians in the middle of Japanese mass killings. I don't see how the politics of saving Allied civilians would let Olympic/Majestic kick off before Christmas 1945 due to Amphibious shipping shortages.

That puts two months of Pershing production and CDL shipments in theater before the invasion of Japan.

[ChristopherPerrien]

That puts two months of Pershing production and CDL shipments in theater before the invasion of Japan.

Find and Dandy. But for one; While there might have been 5-6 Bn's of CDL's available at the end of the ETO-war(5 IIRC :roll: ). What is the use ? CDL's never did much in WWII or thereafter , so they look alot like a few other "BritIsh invented" luxury/novelty vehicles that never did much on the battlefield. They would only have subtracted resources of numbers of more general purpose/useful vehicles.

As to the real deal here , sure,, allow for another two months production of M26's , but where does that really matter or mean a dam thing when it would have/if it could have come to an invasion of Japan? Japan had no MBT's to speak of , so where would the Pershing have had any advantage over Shermans in its tactical effect?

US forces didn't need a heavy tank to invade Japan , there were no other tanks to fight, that the Sherman couldn't defeat readily. On the other hand if you insist on maximizing the numbers of Pershings during Coronet, you end up reducing the effectiveness of the US Army in general by introducing the extra logistical burden of a whole new "tail" for any units equipped with this, "Newer", "Heavier", and less "familiar" tank.

I.E.. FWIIW, If I was invading Japan in 45 , I'd much rather have 5 Shermans than 3 Pershings, if I could "trade" tanks. And given the certainty on what the fighting would have been composed of , I don't think it would have happened differently. M26's were never necessary in the Pacific theater.

[Mil-tech Bard]

That puts two months of Pershing production and CDL shipments in theater before the invasion of Japan.

Find and Dandy. But for one; While there might have been 5-6 Bn's of CDL's available at the end of the ETO-war(5 IIRC :roll: ). What is the use ? CDL's never did much in WWII or thereafter , so they look alot like a few other "BritIsh invented" luxury/novelty vehicles that never did much on the battlefield. They would only have subtracted resources of numbers of more general purpose/useful vehicles.

As to the real deal here , sure,, allow for another two months production of M26's , but where does that really matter or mean a dam thing when it would have/if it could have come to an invasion of Japan? Japan had no MBT's to speak of , so where would the Pershing have had any advantage over Shermans in its tactical effect?

US forces didn't need a heavy tank to invade Japan , there were no other tanks to fight, that the Sherman couldn't defeat readily. On the other hand if you insist on maximizing the numbers of Pershings during Coronet, you end up reducing the effectiveness of the US Army in general by introducing the extra logistical burden of a whole new "tail" for any units equipped with this, "Newer", "Heavier", and less "familiar" tank.

I.E.. FWIIW, If I was invading Japan in 45 , I'd much rather have 5 Shermans than 3 Pershings, if I could "trade" tanks. And given the certainty on what the fighting would have been composed of , I don't think it would have happened differently. M26's were never necessary in the Pacific theater.

Any combat history of the fighting on Okinawa would tell you how useful CDL's would have been in Kyushu.

The M26 Pershing's front turret and hull were proof from Japanese 47mm gunfire at point blank range -- unless you hit the Machine gun ports -- and the side turret and hull side covering the crew compartment required the 47mm to be at 150 yards or less to get a penetration.

The M4A3 Sherman's turret gun mantle had that level of protection versus a 47mm gun. E.B. Sledge's book has a passage where he describes a shoot out between Marine Shermans and 47mm guns where 47mm's bounced off the front turrets of a pair of Marine M4s and their return fire killed the 47mm's.

However, late model M4A3's hull could be punched through by a 47mm at 500 yards and both the turret and hull side could be punched through at a thousand yards.

Between it's armor, and the hitting 90mm gun versus concrete compared to the medium velocity 75mm gun, the combat power of three Pershings versus a 47mm armed Japanese anti-tank gun line supporting cave positions represented roughly that of 10 Sherman's.

It is a lot easier to move and support three Pershings and have three replacements in the cargo ships off shore than land 10 Shermans and obtain shipping space for 10 replacements.

[binder001]

[quote="ChristopherPerrien Find and Dandy. But for one; While there might have been 5-6 Bn's of CDL's available at the end of the ETO-war(5 IIRC :roll: ). What is the use ? CDL's never did much in WWII or thereafter , so they look alot like a few other "BritIsh invented" luxury/novelty vehicles that never did much on the battlefield. They would only have subtracted resources of numbers of more general purpose/useful vehicles..[/quote]

The CDL "never did much in WWII" because of restrictions on their use. In short version - the Brits and US were so worried that a premature use of the device would eliminate the shock value. They each agreed not to use the device without consultation with the other. The extreme secrecy involved with the project also kept frontline commanders from learning that such a resource was available. So the problem wasn't that the device didn't work, it worked well enough to inspire excessive secrecy. There are reports that the lights were relatively maintenance intensive, but the US crews had practiced in the California/Arizona desert before moving to England. The SIX battalions, along with the two armored group HQs and other support troops were held in England until the fall when several of the units started to be reconfigured from "Medium Tank Battalion, Special" to regular Medium Tank Battalions and sent to the continent. Two of the battalions, the 738th and 739th were held out as special operations armor units. The 738th went to FUSA and the 739th went to NUSA, both primarily as Mine Exploder units, but they also ended up operating some flame thrower tanks, some CDLs for guarding the bridge sites at Remagen, and other tasks. Somewhere in the ETOUSA were the bulk of the 300+ "T10 Shop Tractors", aka "Leaflets" or "Heaters" that had been produced. The M3/M3A1 CDL still retained a 75mm gun for offensive use. Army Ordnance had experimented with CDLs based on the later M4A3 versions, but these probably wouldn't have been available for the invasion of Japan.

[ChristopherPerrien]

Again CDLs :roll: , Even barring that they were so "top-secret" they were rarely used. I know of only one incident in WWII . "a nightime river crossing" that they were actually used and were considered "effective/useful". Past that , SQUAT! And I have my doubts to the one incident , because the judgment of the CDLs was done/written by advocates of them, not neutral observers.

But hell who cares. Let's waste 5/6/10/12/etc, battalions of tankers and alot of attendant support personnel and logistics, manning a few hundred OLD tanks with high maintenance issues just because, "THEY JUST MIGHT" prove useful in a tiny number of instances on few dark nights. :roll: And god knows , we'll know days in advance, just where and when those battalions will be able to prove their "usefulness" and we''ll be moving them there in advance.

CDLs sounds like good economic sense to me. Good tactical reasoning too. However where's the crystal ball to know days/weeks in advance the where and the when they might HAVE WORKED?????????? IF at all????

A flickering strobe light is something to shoot at and easily seen. All active light sources used in war have simple solutions/antidotes, which is why active IR and Xenon lights are no longer used either. After "ONE" time , I imagine the remedy to CDLs would be readily apparent -a pair of welder's googles or some other simple dark filter. And shoot.


Why do you think were they not used in korea , vietnam, or still today?

ERGO _" "Shinin rabbits" can be fun , till the rabbits start shooting back".

[binder001]

I have another note to add to your distatste for the CDL. Back in the 70's I used to be able to get various Armor studies via interlibrary loan. I can't remember the exact report but one observer wrote that with the desert sun filter applied to an 88mm gun sight he could clearly see the lighted slot on the CDL. I wish I could remember the exact report that mentioned this - it wouldn't bode well for the survival of the CDL crews after the Germans discovered that little fact.

By the way, CDLs weren't used in Korea, but towards the end of the conflict there was an increasing use of the tank-mounted searchlights on M46s. Later lights also appeared in Viet Nam on Army and Marine M48A3s.

[Carl Schwamberger]

We were still training with the xenon searchlights in the 1980s. Godawfull effective as I remember, & no they were not sitting ducks in the hands of properly trained company commanders. Consider getting flashed in the face by one or two for a second at 300 meters . Does nothing for your night vision. At fifty meters you might as well have been shot. I'll leave the indirect lighting, and direct lighting techniques for another time.

Back in the 1970s there were refrences in our training, and from combat vets, to strobe lights being used for battlefield illumination, and to dazzle enemy gunners. So in that sense the CDL principle was used in at least in the Viet Nam war.

Night vision devices have advanced far beyond what was available to us back in 1983, or 1991 for that matter. Then they were nice supplements but not a substitute for high powered illumination weapons.

From some old reading concerning the crossing of the Rhine River:

They were used by US forces in guarding bridges in the crossing of the Rhine. The Germans attacked the bridges at night using floating mines & swimmers. The armored CDL made them resistant to the artillery fire the Germans directed at the bridges. The German commando swimmers captured told the interrogators they were dazzled & disorientated by the American search lights flickering on the water.

[ChristopherPerrien]

Hi Carl and Binder,

To quote a highly respected character, "Ain't it the truth."

CDL's were CDL's, -Canal defense lights. They had lttle use offensively and their only record of success was defending a Rhine river bridge against an attack by a squad of german commandos.

Surely a, "strobe light", makes it slighty harder to walk across a discotech floor, BTDT(been there done that), which is what those German UDT's mentioned, and that i "sort of" inferred earlier.(Thanks Carl)

The German commando swimmers captured told the interrogators they were dazzled & disorientated by the American search lights flickering on the water.

And (thanks Binder) for the note of those 88 gunners.

I can't remember the exact report but one observer wrote that with the desert sun filter applied to an 88mm gun sight he could clearly see the lighted slot on the CDL.

I fail to see the use of C.D.L.'s as being positively tactically/ecomically effective for Coronet, if anything they would have subtracted from the overall offensive capability of US/Allied forces for Coronet. And I don't see the US Army of 1945, invading Japan ,having the need for CDL's . I.E.- We weren't gonna be sittin' on one side of the Yamoto river for coupla' months waiting on a "Banzaii" charge.

BTW, I have had the "privelege" :roll: , of working/living on a M60A1/RISE , for a few months in 1988, so I do slightly understand some of the complexities with the good ol' " CDL" system.

Mcuh regards, Chris

Let's get back to Pershings, As I think earlier in this topic, or somewhere else, that we have debated that the side armor protection of later modified Shermans was equal ,if not better than the side armour of M26's, which were both proof against Jap. 47MM AT guns at all but short ranges: Or/And also, "overall:", that the late model US Shermans were hardly less protected(if not equal or better ) to original M26 Pershings at various angles of attack.

I'll go find the relevant topics/posts soon, I think "Darrin" posted the original figs ,"somewhere", and I don't think there was any probelem with his math.

[Mil-tech Bard]

>>I fail to see the use of C.D.L.'s as being positively tactically/ecomically effective for Coronet,

Think fewer star shells fired.

There was a shortage at Okinawa due to Japanese night time infiltration tactics, as opposed to attacks.

[Mil-tech Bard]

>As I think earlier in this topic, or somewhere else, that we have debated that the side armor protection
>of later modified Shermans >was equal ,if not better than the side armour of M26's, which were both
>proof against Jap. 47MM AT guns at all but short ranges: Or/And also, "overall:", that the late model
>US Shermans were hardly less protected(if not equal or better )

There was no difference in the side armor basis of late model versus earlier Shermans (leaving out the 252 Jumbo assault tanks). The US Army Ordnance manuals make that very clear. Some Shermans that were upgraded got a armor plate welded over their dry ammo storage sponson area. That is it.

Everyone quoting thicker M4A3 side armor figures seems to be accessing the same flawed on-line data base.

Now, you _can_ add on armor to the front and sides of a Sherman, however, you run into both big landing craft and ground pressure mobility issues.

The late model M4A3 let alone M4A3 (HVSS) were too heavy for LCM-6.

M4A3 VVSS Shermans were, as Iwo Jima showed, suffering from too much ground pressure -- even with extended end pin connectors -- as it was. That is why the "E9" upgrade of VVSS Shermans with dual extended end pin connectors was created.

Plus earlier 2-inch front slope model Shermans, with enough add on armor to be effective versus 47mm, had the same over weight for LCM-6 landing craft issue.

All that having a up-armored M4 Sherman bought you compared to a Pershing -- in terms of landing craft -- is the ability to use the LCT-5 rather than getting up to an LCT-6 landing craft.

At Iwo Jima the USMC had to use LSM landing ships for its M4A3's for just that reason.

[Carl Schwamberger]

>As I think earlier in this topic, or somewhere else, that we have debated that the side armor protection
>of later modified Shermans >was equal ,if not better than the side armour of M26's, which were both
>proof against Jap. 47MM AT guns at all but short ranges: Or/And also, "overall:", that the late model
>US Shermans were hardly less protected(if not equal or better )

There was no difference in the side armor basis of late model versus earlier Shermans (leaving out the 252 Jumbo assault tanks). The US Army Ordnance manuals make that very clear. Some Shermans that were upgraded got a armor plate welded over their dry ammo storage sponson area. That is it.

Everyone quoting thicker M4A3 side armor figures seems to be accessing the same flawed on-line data base.

I wonder if there was a significant difference in the M$ series vs the T26 side armor, other than thickness. Looking at a M4 & M26 side by side I noticed the following:

1. the M4 hull is at least 10cm or four inches higher than the M26. Side by side the M4 hull looks even taller but we made a rough measurement.

2. The upper side armor of the M26 was sloped, vs the vertical side of the M4. It was not clear what difference there was in the slope behind the tracks.

3. Overall the M26 had the apperance of far less vulnerable sides due to the larger proportion of coverage by the tracks & rollers. The M4 had a larger area of vertical flat side exposed above the tracks.

4. The front underside or 'return; of the M26 was of less surface area than the M4, and the transition or nose was several cm lower than the M4. the apperance was of significantly less exposure of the lower front hull.

[ChristopherPerrien]

[i
Everyone quoting thicker M4A3 side armor figures seems to be accessing the same flawed on-line data base.

Now, you _can_ add on armor to the front and sides of a Sherman, however, you run into both big landing craft and ground pressure mobility issues.

The late model M4A3 let alone M4A3 (HVSS) were too heavy for LCM-6.

M4A3 VVSS Shermans were, as Iwo Jima showed, suffering from too much ground pressure -- even with extended end pin connectors -- as it was. That is why the "E9" upgrade of VVSS Shermans with dual extended end pin connectors was created.

Plus earlier 2-inch front slope model Shermans, with enough add on armor to be effective versus 47mm, had the same over weight for LCM-6 landing craft issue.

All that having a up-armored M4 Sherman bought you compared to a Pershing -- in terms of landing craft -- is the ability to use the LCT-5 rather than getting up to an LCT-6 landing craft.

At Iwo Jima the USMC had to use LSM landing ships for its M4A3's for just that reason.

High ground pressure was a common problem for all Shermans, as side armor it is my recollection that later model Shermans had thicker "side" armor on the top half of the hull (above the track)track than Pershings(103mm to 85MM IIRRC) but the Pershings actual hull armor was thicker than the lower hull armor on Shermans.

You pretty much made my case for equal front armor protection , although I think the Perhsing was slightly thicker a couple mm's, IIRC.

Like I said,IIRC< Darrin posted some interesting figs on this somewhere way back, which I have not found yet. Give me some time to find that, and it was not just some "bs". off the net.

True, the capabilities in armor penetration capabilities to the 75/76 gun as opposed to the 90mm were "dififerent", with thre 90 of course being better, but that I don't think matters much, as most concrete bunkers could defeat most rounds fired by either of these weapons . Big bunkers were really only suppressed by tanks , while other assets moved in for the kill. In respects to just flinging explosive at appertures or hitting them with an AT round , the difference between 75 and 90mm tank fire is not much different in effect to the receiver of such shells.

I.E. the 90mm Pershing was no better a "bunker buster " than the avg late model Sherman. And as far as avg battles would have went against the poorly armored and AT armed Japanese during "Cornet" the Sherman would have benn as effective as the Pershing , and the Sherman was lighter and there were alot more of them around and it was a more familiar tank and it was easier to both land , ship, and support them.

Now if you want to re-fight the "Western Front" I agree that it would have bene better to have a lesser number of Pershings than alot of Shermans on anumber of occasions, but even in that scenario, the point is quite debatable.

Let me try to find those figs.