Late War M4 Sherman Redesign

[Elan Vital]

To elaborate further on the time pressures facing Sherman production...you have to remember that from 30 June 1941 to 6 December 1941, the plan was for an ultimate 27 division army, to be:

9 x Corps HQs and Corps Troops
18 x Infantry Divisions (National Guard)
8 x Infantry Divisions (Regular Army)
1 x Infantry Division (Motorized, Regular Army)
2 x Cavalry Divisions + 1 Cavalry Brigade
4 x Armored Divisions

Four armored divisions with 1941 organization (2 light tk regts, 1 med tk regt / 265 light tanks and 161 medums) gives you a total of 1,060 light tanks and 644 mediums to equip your force.

Add in another division's worth of tanks for training and schools, and you still only need 1,325 lights and 805 mediums. That's possible to meet with a small tank force -- The US Armored Force knew that the hull mount design for the M3 Medium was obsolete and they suggested that production of the M3 Medium be limited to a small number (360 was bandied about), pending completion of the 75mm gun turret design.

BUT, the British needed lots of tanks for the Western Desert; so mass production of the M3 was ordered right away, and any chances of an actual M4 "Improved" went to zero right after Pearl Harbor, because the US Army now had to look seriously at having to build:

60~ Armored Divisions = 9,660 Medium Tanks
70~ Tank Battalions (Medium) = 3,570 Medium Tanks

To equip the Victory Plan, before Marshall did the "90 Division Gamble", in addition to supplying the UK and USSR with tanks...

I wonder what the plans would have been if France didn't fall. If I recall the US Army was still set to expand and some 1000 M2 Mediums had been ordered, but the battle of France would still show that it is no longer suitable.

 

[EwenS]

To elaborate further on the time pressures facing Sherman production...you have to remember that from 30 June 1941 to 6 December 1941, the plan was for an ultimate 27 division army, to be:

9 x Corps HQs and Corps Troops
18 x Infantry Divisions (National Guard)
8 x Infantry Divisions (Regular Army)
1 x Infantry Division (Motorized, Regular Army)
2 x Cavalry Divisions + 1 Cavalry Brigade
4 x Armored Divisions

Four armored divisions with 1941 organization (2 light tk regts, 1 med tk regt / 265 light tanks and 161 medums) gives you a total of 1,060 light tanks and 644 mediums to equip your force.

Add in another division's worth of tanks for training and schools, and you still only need 1,325 lights and 805 mediums. That's possible to meet with a small tank force -- The US Armored Force knew that the hull mount design for the M3 Medium was obsolete and they suggested that production of the M3 Medium be limited to a small number (360 was bandied about), pending completion of the 75mm gun turret design.

BUT, the British needed lots of tanks for the Western Desert; so mass production of the M3 was ordered right away, and any chances of an actual M4 "Improved" went to zero right after Pearl Harbor, because the US Army now had to look seriously at having to build:

60~ Armored Divisions = 9,660 Medium Tanks
70~ Tank Battalions (Medium) = 3,570 Medium Tanks

To equip the Victory Plan, before Marshall did the "90 Division Gamble", in addition to supplying the UK and USSR with tanks...

I wonder what the plans would have been if France didn't fall. If I recall the US Army was still set to expand and some 1000 M2 Mediums had been ordered, but the battle of France would still show that it is no longer suitable.

With more time to play with, probably skip the M3 Lee/Grant altogether.

With France still in play, and Britain a bit less desperate for tanks right now, maybe some production of foreign types in the USA (Hotchkiss & Somua types or Crusader).

See here for some of the driving factors pushing M3 development forward so rapidly.

British M3, M3A2, M3A3 and M3A5 Grants

 

[RyanC]

I wonder what the plans would have been if France didn't fall. If I recall the US Army was still set to expand and some 1000 M2 Mediums had been ordered, but the battle of France would still show that it is no longer suitable.

Speaking of that,

On 15 August 1940, the USG signed the contract with Chrysler to build the Detroit Arsenal Tank Plant (DATP) for $20~ million ($400M today in 2022), alongside the contract to produce 1,000 M2 Mediums in DATP at a rate of 100 a month finishing in August 1942.

That changed around 29 August 1940 (date not exact), when the USG realized that the M2 medium would be hopelessly obsolete by late 1941; and issued a contract modification that changed the 1,000 tanks from M2 Mediums to M3 Mediums; and M2 Medium production was shifted to Rock Island Arsenal to free up DATP resources to let them concentrate on the M3 Production design.

So if we go by orders of 1,000 tanks at 100 tanks a month for a ten month production run, the following hypothetical schedule comes out; when we combine it with Armored Force's desire to hold M3 Medium production to about 400 tanks and shift to the 75mm Gun Turret ASAP:

M2 Medium: October 1941 to August 1942
M3 Grant/Lee: July 1942 to October 1942 (Production terminates at 400 tanks)
M4 Sherman: September 1942 to June 1943
M5 Improved Sherman: May 1943 to Feb 1944

By contrast, in real life (IRL) production was:

M3: July 1941 to December 1942
M4: March 1942 onwards

This shows just how "time compressed" US tank design got; large amounts of components were recycled "forward" in each design:

M3 Lee/Grant: Suspension, Tracks, Engine of M2 Medium.
M4 Sherman: Lower Hull of M3, power train, engine, suspension, etc of M3 Lee/Grant.

In fact, the hull sponson gun design for the M3 apparently drew a lot of work from work done for the Howitzer Motor Carriage T3, it seems, allowing it to be designed for production faster, enabling a quicker "release for production" for the entire M3 Medium.

 

[RyanC]

I just OCRed a memo for General Marshall on the T23 (gas electric tank), dated 25 April 1944 that has some useful information for this thread.

In it, General Handy tells Marshall regarding the T23:

It is understood that in view of the great apparent promise of this design the order for 250 of these tanks was placed before any real tests had been conducted and that this action was necessary in order to avoid a delay of at least six to nine months.

Another memo I OCRed was dated 4 December 1943 and was a answer for General Devers as prepared by G-4; where they state:

Reference your message 14 November 1943, development and testing of T-25’s and T-26’s are progressing. 40 T-25’s and 10 T-26’s are being produced for service tests. Production of 250 T-26’s not favorably considered until first models have been tested. 90mm Gun is being mounted on M10A1 Gun Motor Carriage and designated “The T-71.” 500 T-71’s have been ordered for earliest possible production.

So if you want to change the course of US Armored history, you need to convince a lot of people in 1943ish to turn the T26 program into a concurrent program (testing done alongside design/production).

Huge Risks are involved. The Panther is the best example in WW2 of a "concurrent" program

 

[RyanC]

OCR'ers note: First Page has a typewritten in red note saying: 3 June 1944 "To be reopened 1 Sep 44 - as per Col. Sanger's instructions" ---gmd--​

THE ARMORED FORCE BOARD
FORT KNOX. KENTUCKY​

LTH/ms

5 May 1944​

SUBJECT: Armament for Medium Tanks for 1945 Production.

TO: The Commanding General, Army Ground Forces, Army War College, Washington, D. C.

1. The European Theater of Operations has been asked to state its requirements for armament for 1945 production of medium tanks. Colonel Heath who left London on Monday, 1 May 1944, brought the following tentative information which it is believed will he contained in the answer submitted by the European Theater of Operations stating requirements for armament. The requirements set forth herein must be considered as tentative until the official reply has been received, by the War Department from the European Theater of Operations The following requirements were tentatively set up in ETOUSA headquarters on Monday, May 1:

a. Armament. The theater wants armament as follows:

105-mm Howitzer (75% of the tanks).
90-mm Gun (25% of the tanks)

The two types of armament are definitely desired. The proportions must be considered as tentative.

b. Ammunition. Seventy (70) rounds of ammunition is the minimum acceptable in each tank, with both types of weapon. Seventy (70) rounds is to be considered as the minimum figure -- more rounds are urgently desired.

c. Mobility. The theater desired no reduction in mobility. Additional armor is not desired if it cuts into mobility. The theater considers the mobility of Medium Tank, M4A1, (radial engine), as unsatisfactory because it is under-powered. The standard of mobility desired is the Medium Tank, M4A3, (Ford engine).

d. Width. Widths greater than 124 inches are acceptable only if bridges capable of handling the wider tanks are furnished.

e. Bow Machine Gun. The bow machine gun to be retained.

f. It must be kept in mind that tanks must be moved by transporters.

g. Reduced unit ground pressure is desired.

2. In accordance with verbal instructions of Commanding General, Army Ground Forces, the following discussion and recommendations on means of meeting the European Theaters of Operations requirements are presented.

a. Medium Tank, T25E1.

(1) This tank has the following advantages:

(a) Has been designed with the 90-mm gun turret.
(b) Has a torque converter, which simplified, driving.
(c) Has an improved suspension, providing a smoother ride.
(d) Will provide improved ground pressure characteristics if equipped with the Medium Tank, T26E1, (24") track and suspension.
(e) Has a favorable silhouette.

(2) This tank has the following disadvantages:

(a) It will not meet the theater's stated requirement for ammunition. Extreme difficulty is being encountered in providing an accessible stowage of fifty-two (52) rounds of ammunition.
(b) A satisfactory turret for the 105-mm howitzer has not been built.
(c) This tank is a new design and its mechanical perfection is not yet complete. It must be expected that it will have to go through a period of "teething" troubles.
(d) Wide bridges are required if this tank is to be used.
(e) The rate of fire will be very slow unless vast improvement can be made in the ammunition stowage. This improvement is doubtful.
(f) Progress is slow on the development of a smokeless, flashless round of ammunition for the 90-mm gun.
(g) The time required to place this tank in production will be considerable and it is estimated that adequate quantities for combat service cannot be available before May 1945.
(h) Considerable training will be required when units previously equipped with Medium Tanks, M4 Series, are reequipped with this tank.
(i) When the T26E1 track and suspension are added the weight of the tank now at 78000 pounds will be increased between 2000 and 3000 pounds.

b. Medium Tank, M4A3, with 90-mm Turret. It is possible that the requirements for the European Theater of Operations can be met by mounting a 90-mm gun turret, similar to the T25 design, on the hull of the Medium Tank, M4A3. The hull of Medium Tank, M4A3, will be equipped during the latter part of 1944 production with the 23-inch track and the horizontal volute spring suspension.

(1) Such a tank will have the following advantages.

(a) It is estimated that between 60 and 70 rounds can be stowed in this tank without overcrowding the fighting compartment.
(b) There is in production in 1944, a 105-mm Howitzer turret on this tank.
(c) The mechanical components of this tank are very well developed and proven.
(d) The change in spare parts to insure adequate maintenance will be a minimum.
(e) The re-training required for troops to be re-equipped with this tank will be a minimum.
(f) This tank can use existing 124-inch bridges.
(g) This tank can be transported on existing transporters.
(h) The time required to place this tank in production will be a minimum, since no new hull and mechanical components are required. The principal design work required will be to design the stowage arrangements.

(2) This tank will have the following disadvantages:

(a) Increase in height of silhouette due to the greater height of the 90-mm turret. (Approximately 4-3/8 inches over the M4A3 with 76-mm gun and one foot higher than T25E1).
(b) Will have less armor protection than the Medium Tank, T25E1, but will be equal to the M4 on the hull and greater on the turret.
(c) The suspension will not provide as satisfactory riding characteristics as the Medium Tank, T25E1, suspension.
(d) Estimated weight of the Medium Tank, M4A3, with the 90-mm gun turret is as follows:

Weight of Medium Tank, M4A3 w/76-mm Gun and Horizontal Volute Spring Suspension (Actual)	76000 pounds.​
Weight of Turret Assembly, Medium Tank, T25E1	18740 pounds.​
Weight of Turret Assembly, Medium Tank, M4A3, w/76-mm Gun	14250 pounds.​
Difference	4490 pounds​
Estimated Gross Weight of Tank	80490 pounds.​

(3). A new tank involving a new hull design, to meet the requirements of ETO. Such a tank might be built by redesigning the hull of the T25E1 using mechanical components that have been developed for this tank. The main feature of such a redesign would be an increase in the cubic contents of the fighting compartment to permit the stowage of a minimum of 70 rounds of ammunition.

(a) Advantages.
(1) It would provide a hull more properly redesigned for the weapon to be mounted.
(2) A new design would specifically meet the ETO requirements.
(b) Disadvantages.
(1) It would be virtually impossible to complete a new hull design and incorporate production in 1945.
(2) Armor thickness would have to be reduced to accommodate the increased bulk. Thus the increased armor advantages of the T25E1 hull would would be lost.
c. The resulting hull to meet the specific characteristics of ETO would probably closely resemble the hull of the Medium Tank, M4A3.

3. Possible Compromises in Using the Medium Tank, T25E1. The most difficult requirement to meet in using this tank is the requirement for 70 rounds. It is estimated that a maximum of 52 rounds can be installed in the present tank. By eliminating the bow machine gun and bow machine gunner and using this space for ammunition, it is estimated that an additional 18 rounds could be stowed. This ammunition would be without water protection.

Modification of the Hull of the T25E1 to Install Sponsons. This would require increasing the height of the hull, adding considerable armor plate, and in effect, would amount to new hull design since the roof of the tank would have to be raised.

4. Since the European Theater of Operations has established requirements, it is believed highly desirable that they clarify their desires on the following points:

a. When are 90-mm gun tanks desired in combat? If the T25E1 is used, it is unlikely that combat quantities of these tanks can be manufactured before May or June 1945. If M4A3 tanks mounting the 90-mm gun are used, combat quantities might be provided in January 1945.

b. Will the theater accept the Medium Tank, T25E1, with the maximum stowage of 52 rounds of ammunition in order to obtain the advantages of the torqumatic drive, the improved suspension, and additional armor?

c. Will the theater accept Medium Tank, T25E1, with the bow gunner eliminated, in order to meet the requirement of 70 rounds of ammunition?

d. Since it is contemplated by the theater to have the entire 1945 production equipped with 90-mm gun and 105-mm Howitzer, does the theater desire gyrostabilizers on these weapons? The existing turret designs for mounting these guns does not incorporate the gyrostabilizer.

e. With reference to question c, above, if the theater accepts the Medium Tank, T25E1, with a maximum stowage of 52 rounds of ammunition, would the theater desire to introduce a full tracked armored ammunition carrier into the tank organizations to facilitate battle field re-supply of ammunition to individual tanks?

f. Will the theater accept the Medium Tank, M4A3, mounting a 90-mm gun including the following features, as meeting their requirement?

(1) 23-inch wide track.
(2) Horizontal Volute Spring Suspension.
(3) Gross weight of approximately 80,400 pounds.
(4) High speed reverse.
(5) Increase of silhouette 4-3/8 inches above M4A3 w/76-mm gun.
(6) Ammunition stowage between 60 and 70 rounds.

5. Medium Tank, T26E1. This tank has the same disadvantages and advantages as the Medium Tank, T25E1, except that its increased weight will reduce its mobility and it will thus not meet the European Theater of Operations requirements.

6. In the opinion of the Armored Board none of the available tanks are entirety suitable as 90-mm gun-carrying tanks. It appears that none of them will completely meet the requirements established by the European Theater of Operations. The Medium Tank, T25E1, has its principal deficiency in the matter of ammunition stowage and incomplete development. The Medium Tank, M4A3, with 90-mm gun turret has less disadvantage in the matter of ammunition stowage, but has greater advantages from the standpoint of being readily placed in production, causing less disturbance in the spare parts supply, and in the training of troops. In the opinion of the Armored Board, the use of a 90-mm turret on the M4A3 chassis: offers the most promising means of meeting the European Theater of Operations requirements. A powerful consideration in this opinion is the fact that, with proper support, the Medium Tank, M4A3, with 90-mm gun can be made available in combat quantities from six to eight months earlier than the T25E1. Both the Medium Tanks, T25E1, and the Medium Tank, M4A3, with the 90-mm gun, when ready for battle will weigh approximately 80,000 pounds. Thus it appears that neither solution -will entirely meet the European Theater of Operations desires in the matter of mobility. In any event, adoption of either the Medium Tank, T25E1, with T26 suspension, or the Medium Tank, M4A3, with the 90-mm gun, can be regarded as only an unsatisfactory expedient for providing a 90-mm gun tank. Every effort should be made to design a tank that will be a satisfactory 90-mm gun tank.

7. The most important consideration in determining which expedient will be used to meet the European Theater of Operations requirement is the question of when 90-mm gun tanks are required on the battle field in Europe. For this reason it is believed essential that the European Theater of Operations be queried on the points enumerated in paragraph 4, above.

8. The Armored Board recommends that:

a. Based upon the limited information at the present time available, the Medium Tank, M4A3, mounting a 90-mm gun turret be considered as the most promising means of meeting the European Theater of Operations requirement for a 90-mm gun tank.

b. Before a final decision is taken, the European Theater of Operations be asked to provide answers to the questions raised in paragraph 4, above.

c. The design begin immediately to provide a 90-mm gun tank of improved design that will meet the characteristics recently forwarded by the Armored Board.

/S/
FRANK R. WILLIAMS
Colonel, Infantry
President​

 

[RyanC]

NARA II, COLLEGE PARK, MD​ RG 165 NM 84 E486 Box 34 Folder 400 TANKS Medium T23​ DECLASSIFIED VIA NND 760139​

SECRET​

WAR DEPARTMENT
NEW DEVELOPMENTS DIVISION
WASHINGTON 25, D. C.​

23 May 1944​

MEMORANDUM FOR GENERAL HENRY:

Following are some of the more important happenings during your absence:

Medium Tanks​

G-4 called a meeting to consider ETO recommendations for 1945 type of medium tanks. The discussions developed the following:

a. 90mm gun can be furnished with M-4 type tanks; 105mm can be mounted on these vehicles and the change over can be effected at once.

b. By eliminating water protection of ammunition, the T-25 and T-26 tanks will take 72 rounds of 90mm ammunition.

c. Increasing the width of tracks on M-4 and T models present bridging problems; also injects transportation difficulties as present vehicles will probably not take new bridging equipment.

d. The present steel treadway bridge will not take vehicles weighing in excess of 40 tons or those that exceed 124" in width.

e. The present engineer bridge program calls for the development of 25 ton, 50 ton and 80 ton bridges, and the engineers feel certain that they can meet any bridge problems presented by the tank program except that they will have to make a study of transportation requirements.

The ETO tank requirements as compared to those of other theatres are so radical that further study is necessary to determine what course of action is to be taken; that is, whether to settle on one type of tank or go into production of several models. The decision reached was that AGF would make the study and submit specific recommendation to G-4.

With reference to ETO recommendation that the production of light tank T-24 be pressed, G-4 stated that the present program calls for 5600 of these vehicles of which number 1800 will be produced this year and the remainder 1945. The production model is now under test by AGF and it is expected that the T-24 will be standardized by June 15th. As soon as this is done, OPD will advise all theatres and get their requirements for the light tank

4. Characteristics of the 1945 medium tank as laid down by ETO can be found in Cable No. CM-In 13704, 18 May 1944.

 

[JWilly]

I wonder what the plans would have been if France didn't fall. If I recall the US Army was still set to expand and some 1000 M2 Mediums had been ordered, but the battle of France would still show that it is no longer suitable.

I think the French side of the Anglo-French Purchasing Committee had discussed ordering a large number of M3 mediums, to be paid for in cash, but hadn't yet finalized that order as of May 1940.

 

[kocovgoce]

yugoslavija so-122 or m4 with 122 mm gun

 

[Elan Vital]

I wonder what the plans would have been if France didn't fall. If I recall the US Army was still set to expand and some 1000 M2 Mediums had been ordered, but the battle of France would still show that it is no longer suitable.

I think the French side of the Anglo-French Purchasing Committee had discussed ordering a large number of M3 mediums, to be paid for in cash, but hadn't yet finalized that order as of May 1940.

Do you mean M2s? M3 didn't exist until after the battle.

I just OCRed a memo for General Marshall on the T23 (gas electric tank), dated 25 April 1944 that has some useful information for this thread.

In it, General Handy tells Marshall regarding the T23:

It is understood that in view of the great apparent promise of this design the order for 250 of these tanks was placed before any real tests had been conducted and that this action was necessary in order to avoid a delay of at least six to nine months.

Another memo I OCRed was dated 4 December 1943 and was a answer for General Devers as prepared by G-4; where they state:

Reference your message 14 November 1943, development and testing of T-25’s and T-26’s are progressing. 40 T-25’s and 10 T-26’s are being produced for service tests. Production of 250 T-26’s not favorably considered until first models have been tested. 90mm Gun is being mounted on M10A1 Gun Motor Carriage and designated “The T-71.” 500 T-71’s have been ordered for earliest possible production.

So if you want to change the course of US Armored history, you need to convince a lot of people in 1943ish to turn the T26 program into a concurrent program (testing done alongside design/production).

Huge Risks are involved. The Panther is the best example in WW2 of a "concurrent" program

The best way to get an optimized 90mm gun tank in time in hindsight would have been to order development of the "T25" at the same time as all the T2X variants in late 1942. It could even replace the 3" M7 versions that never saw the light of day since they are very similar in concept (T2X with a gun of larger size and weight than the 76).

 

[Grey Havoc]

Essentially, just as the M4 was entering production; they put out RFPs for an improved version; getting replies back from Aberdeen Proving Ground and Detroit Tank Arsenal with two different "improved" M4s.

Incidentally, there is an article regarding a lovely scratchbuilt model of the APG proposal in the July 2022 edition of Military Modelcraft International (there is a small bit of detail on the Detroit Arsenal submission as well).

 

[RyanC]

The best way to get an optimized 90mm gun tank in time in hindsight would have been to order development of the "T25" at the same time as all the T2X variants in late 1942. It could even replace the 3" M7 versions that never saw the light of day since they are very similar in concept (T2X with a gun of larger size and weight than the 76).

Regards that:

The present steel treadway bridge will not take vehicles weighing in excess of 40 tons or those that exceed 124" in width.

T25E1 card was 38.3 US tons combat loaded, and width was 124 inches.
T26E1 card was 42.85 US tons combat loaded and width was 134 inches.

In one of the letters I posted above, when discussing the T25, they say:

Wide bridges are required if this tank [T25] is to be used.

I think part of the issue with the T25/T26 was that the Army spent too much precious time dithering over whether or not to go there; because either tank would require all new bridging -- whether by using up all safety margins (T25) or going over them massively (T26) that eventually they went with the T26 because...if you're going to have to replace all that bridging...go big anyway.

 

[Elan Vital]

The best way to get an optimized 90mm gun tank in time in hindsight would have been to order development of the "T25" at the same time as all the T2X variants in late 1942. It could even replace the 3" M7 versions that never saw the light of day since they are very similar in concept (T2X with a gun of larger size and weight than the 76).

Regards that:

The present steel treadway bridge will not take vehicles weighing in excess of 40 tons or those that exceed 124" in width.

T25E1 card was 38.3 US tons combat loaded, and width was 124 inches.
T26E1 card was 42.85 US tons combat loaded and width was 134 inches.

In one of the letters I posted above, when discussing the T25, they say:

Wide bridges are required if this tank [T25] is to be used.

I think part of the issue with the T25/T26 was that the Army spent too much precious time dithering over whether or not to go there; because either tank would require all new bridging -- whether by using up all safety margins (T25) or going over them massively (T26) that eventually they went with the T26 because...if you're going to have to replace all that bridging...go big anyway.

Agreed, although it's a trade off between the potentially better mobility and reduced wear of the T25E1 (assuming use of the reinforced T26E1 components as was intended) and the Pak/KwK 40 resistance/immunity of the T26. Then again if all weight limits of logistics equipment were exceeded then it might also have been better to go all in and add a more powerful engine (Ford V12 or Chrysler A65 when the latter was considered for heavy tanks) for a couple extra thousand pounds.

If anything, considering the US had to change their logistical equipment anyway, going all in early (as in when T2X started) would have at least given the engineers more time to make the new bridging/transport equipment. Alas, Ordnance is rarely so clairvoyant.

 

[kocovgoce]

t 20

 

[RyanC]

Just OCRed this letter about bridges:

NARA II, COLLEGE PARK, MD​ RG 165 NM 84 E486 Box 33 Folder 400 TANKS​ DECLASSIFIED VIA NND 760139​

[OCR'ers Note – A torn off scrap of paper was stapled to the letter with the following handwritten on it:]​ Gen Barnes & G-4 are agreeable to this plan. [illegible signature]​

SECRET​

WAR DEPARTMENT
NEW DEVELOPMENTS DIVISION
WASHINGTON 25, D. C.​

22 December 1944​

MEMORANDUM FOR GENERAL BORDEN:

SUBJECT: One Kit Widening for 120 Foot D.D. Bailey Bridge.

Colonel Dean, Army Ground Forces called this office regarding the urgent need of shipping one kit widening for 120 foot D.D. Bailey bridge with the T-26 tank. Unless this kit is supplied at the time the tanks are shipped overseas, they will be unable to use the equipment.

Captain Pardue, Distribution Division, Army Service Forces was contacted regarding the possibility of including this bridge with the shipment of tanks and under the same shipping instructions. He advised that this was satisfactory and gave the following markings to be applied to the bridge shipment:

HAIL-AA-ORD 11-STO-S.A. 300 New York P.O.E.​

This will put the bridge on the same boat or with the same shipment as the T-26 tanks and all arrive at the same location.

This information was relayed to Colonel Sykes, Office Chief of Engineers to make arrangements that the bridge kit will arrive at the Port of Embarkation in time.

Colonel Dean was informed of the arrangements.

/S/
HAROLD W. LISSKE,
Major, G. S. C.​

 

[RyanC]

To swerve this back onto topic re the title: "Late war M4 Sherman Redesign":

I have a copy of I believe the complete T20 history

NATIONAL ARCHIVES II RG 156 NM-26 ENTRY 646A BOX A797 DECLASSIFIED VIA NND 735001 OFFICE CHIEF OF ORDNANCE TECHNICAL DIVISION WASHINGTON, D.C. MEDIUM TANK T20 SERIES HISTORY

And it includes a copy of the letter that started it all off:

O.O 451.25/517 (C)
Headquarters, SOS
May 24, 1942

EEB/h/ACM/ai

SPPDE/SPRMD 470.8

MEMORANDUM FOR THE CHIEF OF ORDNANCE

Subject: Production of Pilot Model Medium Tank M-4X

1. The Chief of Ordnance is authorized and directed to proceed with the construction of a pilot model of the medium tank, model M-4x. This confirms verbal authorization from the Commanding General, Headquarters, Services of Supply, to General Barnes, Office Chief of Ordnance, this date.

2. The general objectives for this tank model as tentatively approved by the Chief of Staff are for 4" armor, 75mm. full automatic armaments, 25 mph speed, and 32 ton weight limit. It is understood that General Motors (Fisher Division) are equipped to construct this pilot model without delay.

3. Research and development funds now available to the Chief of Ordnance are applicable to this project.

By command of Lieutenant General SOMERVELL:

LUCIUS D. CLAY,
Brigadier General, General Staff Corps
Deputy Chief of Staff for Requirements and Resources

 

[riggerrob]

Something I do wonder about, given the Meteor adaptation of the Merlin and all the Packard Merlins, why no like use in US tanks of the time?

Merlin engines were prioritized for high-altitude Spitfires, Lancasters and Mustangs because Rolls-Royce was a world leader in super-charger design.
OTOH the American Allison V-1710 engine looked similar, but lacked the super-charger needed to produce full power at 20,000 or 30,000 feet above sea level. So it would have made more sense to shift Allison production to AFVs. Note that Allison V-1710 had a long bell housing bolted to the front. That bell housing contained a propeller speed reduction unit that would be deleted in an AFV. Then V-1710 would need a bespoke, adaptor to the transmission.

 

[Magman H]

Post war Sherman Flamethrower Tank, T33.Jumbo ? with HVSS suspension and flame thrower coaxial gun. Only 3 Pilots were completed. as the end of WW2 the rest were cancelled. The T33 wasn’t completed until 1947. Two of the T33 tanks were converted in 1953 to Self Propelled Flamethrower T88. ( Information The Shadock Free Fr )

 

[kocovgoce]

the last sherman in the picture is a flamethrower. An interesting concept that maybe be modified to fire ss-10 missiles for example

 

[JWilly]

I wonder what the plans would have been if France didn't fall. If I recall the US Army was still set to expand and some 1000 M2 Mediums had been ordered, but the battle of France would still show that it is no longer suitable.

I think the French side of the Anglo-French Purchasing Committee had discussed ordering a large number of M3 mediums, to be paid for in cash, but hadn't yet finalized that order as of May 1940.

Do you mean M2s? M3 didn't exist until after the battle.

As we see in OTL orders placed by the FBPC for fighters, bombers and transport trucks, such orders were unconstrained by US military adoption of particular designs, before or after FBPC's decisions.

The French via FBPC purchased a large number of civilian-industrial-model transport trucks from General Motors...the ACKW353, and other related models. Later, that truck was adopted by the US military with a new cab-body, different tires and other modifications as the CCKW353 and related models.

The French via FBPC purchased Curtiss Hawk 75 aircraft before the USAAF did so. Ditto for the Lockheed 322, which became the P-38, and the DB-7 which after further design evolution became the A-20. Orders were placed for the Hawk 81 and the Hawk 87 as well, before those designs were adopted by the USAAF, though not received before the French defeat.

Both the French and the British also discussed with US manufacturers their interest in a high performance fighter, and those expressions of purchasing interest led to development of that plane being privately funded...and that plane was bought by the British before the USAAF eventually became interested and it became the P-51.

My understanding is that the French saw the shortcomings of the M2 Medium tank design, and had no interest in it, but instead specified to the manufacturers that they wanted a tank essentially equivalent to their own B1 design, i.e. a hull mounted 75mm gun with both AP and HE capability, and a separate turret with a high velocity smaller-caliber cannon with AP ammo. That's what the M3 Medium turned out to be; the French order however predated the formal designation of the M3. Saying that the French had ordered M3 Mediums is just convenient shorthand, since the design had no commonly known name before it became the M3 Medium.

 

[Rl3]

Just read:
"In 1953, Finland designed for Israel a version of the Sherman armed with a 75 mm cannon of Finnish production, but the project was not accepted by Israeli engineers."

(Source: https://tanks-encyclopedia.com/coldwar/Israel/M50-51_Super-Sherman.php)

Anyone got anything on this Finnish/Israeli program?


Regards
Pioneer

Here you have a cut-out from a brochure on the 75mm Finnish anti-tank gun, a drawings of the gun's mounting in the Sherman's turret plus a photo of the gun. It was designated as 75 K/44 and used German ammunition for the Pak 40 anti-tank gun, i.e. 75x715R.

Piotr

Since 75 K / 44 was mentioned here, I will add more photos of her.

 

[kocovgoce]

​

M4 with FL 10 OSCILLATING turret

 

[moin1900]

JAPANESE TURBINE POWERED M4A3 SHERMAN TANK

https://www.reddit.com/r/Warthunder/comments/9i9je3

View: https://www.reddit.com/r/Warthunder/comments/9i9je3/japanese_m4a3_powered_by_a_t53_turboshaft_engine/


Color Photo Sherman tank with turbine

https://global.kawasaki.com/en/corp/profile/division/gasturbine/history.html

 

[riggerrob]

In a whimsical “RCAF’46” thread, I speculated on a Canadian variant on the Sherman Firefly.
Insert a bit of hand-wavium and a 17-pounder gun arrives in Montreal during 1943. Montreal Locomotive Works is already up-to-their-elbows in Ram tank production, but still finds a few spare engineers to develop a new turret to accommodate the new gun. MLW with an almost stock 17-pounder gun, so need to extend the gun Langley farther forward. To balance, they extend the turret bustle well aft. When that is not enough to balance the turret and ease the load on traversing gears, MLW adds aa external turret basket …. then hangs a few spare track links from the extreme rear of the basket to fine-tune balance. The final turret has a pyramidal gun mantlet (ala. Israeli Merkva) and an extended bustle more like a Tiger II.
When MLW gets too busy building Sextons, they keep the foundry busy by casting Canadian-pattern Firefly turrets. Those turrets get sent by rail to Truro, Nova Scotia where an old railway factory swaps turrets from American-made Sherman’s before the tarpaulin-shrouded tanks complete their rail journey to Halifax and are shipped to the UK where their 17-pounder guns are installed.
Meanwhile, someone whispers in the ear of a CARDE engineer, so that pot-sabots get invented a year ahead of OTL.
Another mischief-maker whispers in the ear of another CARDE (Canadian Army Research and Development labs at Camp Valcartier, Quebec) engineer about the need for 17-pounder high-explosive ammo. After intervening in too many late-night fisticuffs, CARDE’s chief engineer assigns two separate teams to develop two distinct HE rounds. The first weighs the same as APDS and uses the same gunsight reticle while the second requires a split reticle to accommodate the two different velocities.
Ah!
Hindsight is always 20-20 …. but we can dream.

 

[JWilly]

Meanwhile, someone whispers in the ear of a CARDE engineer, so that pot-sabots get invented a year ahead of OTL.

Or better yet, someone visiting France in early 1940 hears somehow about Edgar Brandt & Company, an obscure ordnance developer that has a lot of radical ideas, but isn't very successful in selling to the French Army...and upon visiting their offices and lab, hits it off well with Mssr. Brandt and convinces him to set up a sales office in Quebec...resulting in the Canadian Army in 1940 buying WWI-surplus M1897 75mm guns from USA, and 75/57mm APDS rounds for those guns from France, plus a license to manufacture those rounds in Canada.

So, it is Canada that revolutionizes Allied WWII armor fighting by popularizing large caliber sabot ammo...in early 1941.

(And then there's HEAT ammo, but that's a separate story.)

 

[Foo Fighter]

In a whimsical “RCAF’46” thread, I speculated on a Canadian variant on the Sherman Firefly.
Insert a bit of hand-wavium and a 17-pounder gun arrives in Montreal during 1943. Montreal Locomotive Works is already up-to-their-elbows in Ram tank production, but still finds a few spare engineers to develop a new turret to accommodate the new gun. MLW with an almost stock 17-pounder gun, so need to extend the gun Langley farther forward. To balance, they extend the turret bustle well aft. When that is not enough to balance the turret and ease the load on traversing gears, MLW adds aa external turret basket …. then hangs a few spare track links from the extreme rear of the basket to fine-tune balance. The final turret has a pyramidal gun mantlet (ala. Israeli Merkva) and an extended bustle more like a Tiger II.
When MLW gets too busy building Sextons, they keep the foundry busy by casting Canadian-pattern Firefly turrets. Those turrets get sent by rail to Truro, Nova Scotia where an old railway factory swaps turrets from American-made Sherman’s before the tarpaulin-shrouded tanks complete their rail journey to Halifax and are shipped to the UK where their 17-pounder guns are installed.
Meanwhile, someone whispers in the ear of a CARDE engineer, so that pot-sabots get invented a year ahead of OTL.
Another mischief-maker whispers in the ear of another CARDE (Canadian Army Research and Development labs at Camp Valcartier, Quebec) engineer about the need for 17-pounder high-explosive ammo. After intervening in too many late-night fisticuffs, CARDE’s chief engineer assigns two separate teams to develop two distinct HE rounds. The first weighs the same as APDS and uses the same gunsight reticle while the second requires a split reticle to accommodate the two different velocities.
Ah!
Hindsight is always 20-20 …. but we can dream.

Not so far away from reality either. Just that little issue of people on the spot being able to select the right projects to major with.

A fine dream though and it would have shifted some of the force balance too which would have made Heer panzer crew lives that much harder.

 

[GregoryUSSR]

The M4 of the latest versions is a normal tank. Our tankers appreciated them. It was generally considered no worse than the T-34-85.

 

[Elan Vital]

For some curious reason, high capacity HE was required from any tank-mounted development of the 17pdr in 1942/43 but actual development of this round started and bore fruit much later.

The real missed opportunity was with the M10 which had been designed from the start to potentially accept a 17pdr gun, and such a possibility was mentionned both in September 1942 and July 1943. But it wasn't until April 1944 that conversions into the Achilles finally started even though this was much easier to do than Sherman, and thanks to the low weight of the M10, didn't increase roadwheel wear so much the tank had to be slowed down to 15 mph like the Firefly. Even stranger when the UK had been scrambling to get a 17pdr in a self-propelled form since 1941, but ignores the easiest conversion.

Since the installation of the 90mm was similar to that of the 17pdr, the 90mm M10 was also an option on the US side. Due to the weight of the 3" gun, the 90mm didn't change the defects already seen on the basic M10. The new M36 turret was not inherently needed to get the 90mm, but since it solved all the problems with the turret and gun balance, it further reduced weight and improved crew efficiency. The 90mm M10 itself was an acceptable stopgap until the M36.



For the T25/26, there was a clear problem in timing:


The T2X series were started in May of 1942. The 90mm gun was only considered in tanks starting in October 1942 (also over a year after the development of the comparable 17pdr started in the UK). Then the order to develop 90mm T2X series tanks was only made in May of 1943. Looking at improved transmissions to accomodate the full power of the Ford V12 didn't start until December 43, and it wasn't until July 1944 that the Americans truly realized how inadequate the 500hp engine would be on the T26, after the prototypes had been made.

So not only is the development of suitable powerplants for heavy 90mm tanks over a year out of sync, but the 90mm tanks based on a T2X chassis were themselves a year out of sync with the actual hull. There is little doubt that these time intervals prevented the T2X hull to be fully adapted to the extra weight of the 90mm turret, and that as long as a sufficient number of draughtsmen and engineers were available for the job, a 90mm tank program started simultaneously with the 75 and 76mm T2X (for example instead of the redundant 3" T2X) would be considerably more mature by 1944. Most of the pieces were there in 1942 and what was needed was the desire to use the V12 and the 90mm gun to put a clear impetus on the development of suspensions with wider tracks and of suitable transmissions.
Even if all of that was intended only as a "just in case" program.

But it might be better to continue such discussions in the what-if section.

 

[JWilly]

The Grant's and then Sherman's medium-length, medium-velocity 75mm guns, if provided from the beginning with Brandt-design tungsten carbide core APDS shells, would have met every tank-combat performance requirement at practical European combat ranges. No need for much heavier and longer guns, no need for larger ammo, no compromise of HE ammo performance since the candidate guns already had highly effective HE shells. No need for new rounds of tank and gun development, with the wider/heavier-tank-concomitant need for new bridges...at least not right away. 1940 Brandt 75mm APDS offered 900 m/sec muzzle velocity from guns equivalent to the Sherman gun, using artillery-grade propellant. It would have been a much easier solution, able to be implemented years sooner.

 

[Kat Tsun]

JAPANESE TURBINE POWERED M4A3 SHERMAN TANK

https://www.reddit.com/r/Warthunder/comments/9i9je3

View: https://www.reddit.com/r/Warthunder/comments/9i9je3/japanese_m4a3_powered_by_a_t53_turboshaft_engine/


Color Photo Sherman tank with turbine

https://global.kawasaki.com/en/corp/profile/division/gasturbine/history.html

Are there any higher resolution pictures of the T53 powered test hull?

 

[GregoryUSSR]

The Grant's and then Sherman's medium-length, medium-velocity 75mm guns, if provided from the beginning with Brandt-design tungsten carbide core APDS shells, would have met every tank-combat performance requirement at practical European combat ranges. No need for much heavier and longer guns, no need for larger ammo, no compromise of HE ammo performance since the candidate guns already had highly effective HE shells. No need for new rounds of tank and gun development, with the wider/heavier-tank-concomitant need for new bridges...at least not right away. 1940 Brandt 75mm APDS offered 900 m/sec muzzle velocity from guns equivalent to the Sherman gun, using artillery-grade propellant. It would have been a much easier solution, able to be implemented years sooner.

Still, it is better to immediately strive for progress and build reserves for modernization into the product. That would not put on tank boards and sandbags after. And insert new guns into the tower that do not fit there. A lot of people have passed this way.

 

[Foo Fighter]

That the M4 developed into a very useful beast cannot be denied. Lessons learned being incorporated into later builds made it so. Certain terrain made it vulnerable, especially in the early versions with ammunition storage vulnerability and short range infantry weapons/anti tank gun ambushes made short work of many designs.

 

[Scott Kenny]

Still, it is better to immediately strive for progress and build reserves for modernization into the product. That would not put on tank boards and sandbags after. And insert new guns into the tower that do not fit there. A lot of people have passed this way.

Sure it would be.

The next step from the Sherman 75mm with Brandt APDS would have been a 90mm turret, like how the T34 went from the 76mm to the 85mm.

The mechanical reliability requirements for US tanks were so high that it would have taken starting the T26 Heavy Tank project a year sooner to get any Pershings into battle.

 

[T. A. Gardner]

yugoslavija so-122 or m4 with 122 mm gun

Another Yugoslavian Sherman that was used was the M4A3E4. This variant used the M34 turret (normally a 75mm M3 gun) with the 76mm M1 installed instead.

Three of these were used in the movie Kelly's Heroes as a side note.

 

[T. A. Gardner]

While this is totally in the realm of a "What if," somebody could have--the Israeli's?--plopped an M 47 Patton turret on a M4 hull (same turret ring diameter as the M46 and M26) and then swapped out the 90mm for a British / NATO L7 105mm gun and updated fire controls...

 

[Scott Kenny]

While this is totally in the realm of a "What if," somebody could have--the Israeli's?--plopped an M 47 Patton turret on a M4 hull (same turret ring diameter as the M46 and M26) and then swapped out the 90mm for a British / NATO L7 105mm gun and updated fire controls...

That is definitely something I would have expected the Israelis to have put together. Would have had low ammunition capacity and be vulnerable to EVERYTHING on the battlefield, though.

 

[GregoryUSSR]

While this is totally in the realm of a "What if," somebody could have--the Israeli's?--plopped an M 47 Patton turret on a M4 hull (same turret ring diameter as the M46 and M26) and then swapped out the 90mm for a British / NATO L7 105mm gun and updated fire controls...

What for? This is too much. It's better to leave the old man alone. There are normal, modern tanks. We had a T-34-100 theme:

But it was abandoned. And did the right thing. That T-34, that M4 - they are too small and light for such large guns. Of course you can put it, but the output will be an extremely unbalanced machine. Israel did such experiments out of desperation. And if there are T-55, T-62, M48, M60 in sufficient quantity, then there is no sense in this.

 

[Elan Vital]

While this is totally in the realm of a "What if," somebody could have--the Israeli's?--plopped an M 47 Patton turret on a M4 hull (same turret ring diameter as the M46 and M26) and then swapped out the 90mm for a British / NATO L7 105mm gun and updated fire controls...

M47 had a 4" bigger turret ring, but M46E1 with the same turret had the 69" turret ring of Sherman so it should be possible with some ergonomics issues due to the smaller ring. But as noted by the others, if the Israelis could do this then they could upgrade the modern vehicles more instead. Indeed why would they even get M47 turrets instead of complete M47s?

 

[dan_inbox]

IDF captured quite a few M47s and M48s in the collapse of the Jordanian army in 1967.
AFAIK the M48s were used for the Magach fleet, as new units or as source of spares depending on the mark and status, but the M47s were only used for re-selling abroad.

 

[Kat Tsun]

While this is totally in the realm of a "What if," somebody could have--the Israeli's?--plopped an M 47 Patton turret on a M4 hull (same turret ring diameter as the M46 and M26) and then swapped out the 90mm for a British / NATO L7 105mm gun and updated fire controls...

Worse. It had a M26 Pershing turret:



As GregoryUSSR mentioned the T-34-100, this is the American equivalent, and the solution was the significantly bigger Pershing hull.

As a result of the Pershing experience, both the M46 and M47 had 73" diameter vice the M4/M26 69" diameter turret rings, and would be entirely incompatible with the Pershing and Sherman, at least not without significant work. At that point, it was easier to make a larger hull, rather than try to cram a big gun's equally big turret onto a tiny hull.

 

[Scott Kenny]

Worse. It had a M26 Pershing turret:

View attachment 711440

As GregoryUSSR mentioned the T-34-100, this is the American equivalent, and the solution was the significantly bigger Pershing hull.

As a result of the Pershing experience, both the M46 and M47 had 73" diameter vice the M4/M26 69" diameter turret rings, and would be entirely incompatible with the Pershing and Sherman, at least not without significant work. At that point, it was easier to make a larger hull, rather than try to cram a big gun's equally big turret onto a tiny hull.

But for a T-34/85 type upgrade to the Sherman, dropping T25/T26 turrets onto a bunch of Shermans would have been doable in WW2.

Just like how all the 76mm Shermans had T23 turrets installed, but drop the big 90mm in instead of the 76mm. Yes, it would have resulted in a very much disliked number of rounds onboard, the front line troops like having close to 100 rounds of ammunition onboard and demanded at least 75. The Sherman 105 assault guns only had about 60 rounds onboard, so I'd expect a Sherman 90 to have about the same.

This would have addressed the mechanical teething issues that the T26 had. Or rather, given the T26 time to resolve those issues to replace the M4 after WW2.

And it also would have addressed the issues the front line troops complaints about the poor HE shell in the 76mm.

Basically, instead of going from Sherman 75mm to Sherman 76mm using the T23 turret to Pershing, go straight from Sherman 75mm to Sherman 90mm using the T26 turret (or maybe T25, whichever was ready sooner) to Pershing. Same as the M46/47/48 development.