WI more Allied heavy tanks in World War II?

[RamscoopRaider]

I did a post earlier breaking down what it would take to build 5000 M6s, 10,000 M3/M4/M10-M18 all up, was that wrong? Why does it take over 10,000 40 ton Sherman's to get 5000 55 ton M6s; is it the steel, the guns, the engines?

Why 'several times'? The M6 is about 1/3 more tank than the Sherman, why does it require 3 times the logistical footprint: is it the fuel consumption, the ammo consumption, the spare parts consumption

No doubt it will be more limited, there are 10 Shermans for every 1 M6, but the usefulness is an essentially contested concept. I'd say that heavy tanks battalions at the Corps or Army level would find no shortage of work to do, far beyond the limits of thinking when IOTL it was decided not to pursue that development path.

Combination of things, you are setting up a new production line for the M6, so you need to set up lines for all the sub-components that are not being built elsewhere already, in addition by reducing Sherman numbers you reduce the economies of scale its manufacturing gets, so drive up its unit cost and reduce its numbers even more. Then you have resources diverted for heavier LST's, heavier cranes, heavier recovery vehicles, heavier bridging equipment, extra and heavier tank transporters because of the longer routes need to be taken due to greater size, things which get less economies of scale than their middleweight variant, and reduce the economies of scale the middleweights get. You can't really calculate numbers for these things, too many variables, but over 10,000 is a good estimate, I may be conservative

Combination, extra fuel, extra ammo, supply line for different spare parts, much greater use of spare parts (no way in hell it will be near as reliable as the Sherman) heavier engineering requirements, heavier recovery requirements

By useful I mean they would be doing the same things Shermans did, as well as the Sherman's did. There were very few tasks a Heavy Tank would be better than a Sherman for

 

[Riain]

I see the 'logistics' used as if it's a magic wand, rather than simple accounting a schoolchild can do.

Logistics is a numbers game, a tank 1/3 larger than a Sherman will have a logistics footprint about 1/3 larger, not double or triple or 10 times as much. This will be balanced by the fact that its heavier armour will mean it is vulnerable to less weapons therefore will suffer less casualties, reducing the strain on logistics in that way to balance things out somewhat.

As for production, a gun is a gun, an engine an engine so the production cost will be for the steel which is only 1/3 more than a Sherman. Given the US built some 88,000 fully-tracked AFVs in 17 type One more type and 5000 less vehicles isn't going to be a problem.

As for why, the M6 carried the 76mm gun of a TD with more armour than a Sherman, so it can withstand the most fire and kill the toughest targets.

 

[Carl Schwamberger]

Except for the US losing over 10,000 Shermans for 5000 heavy tanks is not a good trade, and in theater the logistic requirements of a Heavy Tank Battalion is going to be several times that of a Sherman Battalion, it is going to be more limited in employment and not very much more useful

Do you have numbers for this? A quick look at the stats for the M6 & T20-T26 types vs the M4 don't show that large a difference. I was not a embarkation officer, but had some training & experience at it. Square surface of deck, cube/volume, and sometimes weight are the considerations. I am away from my notes but memory suggests folks should look up the actual capacity of the cranes fitted to the common cargo ships of the era. The Liberty model was not the only cargo ship type afloat. There were throughout the war many late model commercial cargo ships used, as well as the Victory ship class. I suspect some of the assumptions for capacity of cranes in commercial ports are off too.

Another point would be to look at the commonality of parts between the several models proposed here. While doing that keep in mind that Hunnicutt when researching his book on the M4 Medium tank identified 30,000+ changes to the M4 components during its production run. This included major changes like cast vs welded hull, completely different turret designs, different cannon. If all that can be accommodated production of components for a couple thousand new models looks less intimidating.

Yet another argument is over reduction of M4 production for a new model. this kind of steps lightly over the elimination of other equipment. Specifically a portion of the M10 TD and elimination of the M36 TD. One of the constraints of fielding either the T25 or T26 was the low availability of 90mm guns in 1944. The priority for the 1,200+ cannon made was to the M36 TD. Cancel that & the 90mm cannon are all available for a new tank model.

 

[Andras]

In Korea M26 and M46 tanks were twice as likely to break down as the (already worn out) Shermans. The M46 was slightly worse then the M26. Both types were eventually withdrawn in favor of more Shermans due to their mechanical unreliability.

This means that instead of 1 of 10 Shermans out for maintenance, 1 in 5 of your heavy tanks are. So not only are you shipping over fewer tanks, you have a large potion of them down for mechanical repair. Fewer tanks means less infantry support, which means far more infantry casualties then any reduction in losses in Sherman crews. The crew casualties suffered by Shermans were a vanishingly small portion of NWETO casualties.


eta- And the reason you can't build a large number of warship grade LSTs (i.e. post War LSTs) is because your warship construction slots are filled up. The OTL LSTs were knocked out in large numbers by building them as lightly as possible in merchant slips.

 

[Alamo]

I see the 'logistics' used as if it's a magic wand, rather than simple accounting a schoolchild can do.

Logistics is a numbers game, a tank 1/3 larger than a Sherman will have a logistics footprint about 1/3 larger, not double or triple or 10 times as much. This will be balanced by the fact that its heavier armour will mean it is vulnerable to less weapons therefore will suffer less casualties, reducing the strain on logistics in that way to balance things out somewhat.

The historical records begs to differ. You can't just scale things in such a fashion - the attributes of individual tanks must be taken into consideration. The performance of the M26 in Korea when compared to the Sherman is something of an eye opener in this regard. They required something like triple the man-hours in terms of maintenance, and were still less reliable in the field. There's a reason than the Shermans were brought in to replace their nominal successor, and it wasn't just due to tight mountain roads.

 

[FBKampfer]

To get production of 5000 heavy tanks, you'll need to either take one of the upper-mid level producers of M4's, or basically all of the smaller ones.

The loss of 10000 M4's seems approximately accurate, if not literally.


Additionally, you need separate logistics trains for the heavies, if you want them to be independent units (as is most sensible), requiring men, trucks, fuel for the trucks, new recovery vehicles, probably additional armorers and mechanics, etc.

Equating tank weight with its logistics train is sophomoric in the extreme and demonstrates a basic misunderstanding or simple ignorance of logistical issues, and their complexities.


Furthermore, there is simply no need for a heavy tank. Would they suffer fewer casualties? Maybe, but only equivalent to a few thousand men, given the numbers involved. There were just no German formations or positions that warranted a heavy tank.

 

[marathag]

The WWII Lst and Lct weren't designed for 40 ton tanks, hence the need for dockside cranes. The more heavily built postwar ships were more expensive and took longer to build.

The USN only built 22 new LSTs since 1945. The older LST soldiered on with Pattons, M60s and even M103s. They were mostly gone by time the M1 showed up

 

[marathag]

And they'd still be doing nothing a Sherman couldn't do.

They'd be doing the job that Jumbos ended up doing, because the regular M4s were not up to the breakthru role

 

[marathag]

To get production of 5000 heavy tanks, you'll need to either take one of the upper-mid level producers of M4's, or basically all of the smaller ones.

The loss of 10000 M4's seems approximately accurate, if not literally..

Type Factory Dates Number Produced
M4 (Sherman I) M4 5 U.S. Factories Jul 1942 – Jan 1944 6748
M4(105): (Sherman Ib) M4(105) Chrysler Detroit Tank Arsenal Feb 1943 – Mar 1945 1641
M4A1: (Sherman II) M4A1 4 U.S. Factories Feb 1942 – Jan 1944 6821
M4A1(76): (Sherman II) M4A1(76) Pressed Steel Car Company Jan 1944 – Jun 1945 3426
M4A2: (Sherman III) M4A2 4 U.S. Factories Apr 1942 – Jun 1944 7513
M4A2(76)W: M4A2(76)W 2 U.S. Factories Jun 1944 – Jun 1945 2915
M4A3: Sherman IV M4A3 Ford Motor Company Jun 1943 – Sep 1944 1690
M4A3(75)W: M4A3(75)W Fisher, Grand Blanc Arsenal Feb 1944 – Mar 1945 3071
M4A3(76)W: M4A3(76)W 2 U.S. Factories Mar 1944 – Apr 1945 4542
M4A3(105): M4A3(105) Chrysler Detroit Tank Arsenal Jun 1944 – Jun 1945 3039
M4A3E2: M4A3E2 Fisher, Grand Blanc Arsenal May 1944 – Jul 1944 254
M4A4: (Sherman V) M4A4 Chrysler Detroit Tank Arsenal Jul 1942 – Sep 1943 7499
M4A6: M4A6 Chrysler Detroit Tank Arsenal Oct 1943 – Feb 1944 75
Grand Total: 49,234

Pick a factory.

 

[173rd LRRP]

Very little tank on tank battles in Korea past Nov 1950. http://www.dupuyinstitute.org/ubb/Forum5/HTML/000016.html discussions go over this. Shermans were very good for infantry support and counter fire. Centurion was even better and was known to take several mortar hits without problems when set on British/Australian/Canadian outposts.

 

[9 Fanged Hummingbird]

They'd be doing the job that Jumbos ended up doing, because the regular M4s were not up to the breakthru role

Um, okay? I don't see how that is that a correction, the Sherman Jumbo did the job anyway so no need for a heavy tank.

 

[Pennsylvania]

Um, okay? I don't see how that is that a correction, the Sherman Jumbo did the job anyway so no need for a heavy tank.

Did they ever have a Sherman Jumbo with a 76mm gun, or even a 90mm gun?

 

[9 Fanged Hummingbird]

The 75mm was the standard Sherman gun, so yeah. I think some were also upgunned with the 76mm, but I'm not aware of any Sherman models packing a 90mm during the war.

 

[Alamo]

The 75mm was the standard Sherman gun, so yeah. I think some were also upgunned with the 76mm, but I'm not aware of any Sherman models packing a 90mm during the war.

There was the M36B1.

 

[marathag]

Um, okay? I don't see how that is that a correction, the Sherman Jumbo did the job anyway so no need for a heavy tank.

Only 254. And 3rd Army made hundreds more in their field workshops, by torching plates from knocked out tanks

They had to make their own heavy tanks

 

[Cryhavoc101]

It seems to me that the only reason that the US did not build 5000 M6 Heavy tanks from Sept 1942...is because they chose not to...not because they couldn't.

Now for a POD: Let surmise that the knowledge of the Tiger tank is learned earlier and perhaps intel scares the bejeezus out of the Allied leaders in 'confirming' that 1000s are being built and any thought of relying solely on the M4 dissapear

So instead of having Tank Destroyer battalions attached to each Division the powers that be decide instead to re-roll those units as heavy tank Battalions equipped with the M6 - with their expected mission to be both a breakthrough tank and to act as heavy Tank Destroyers (instead of the M10s).

Initial production of the tanks starts at Baldwin Locomotive at Eddystone, Pennsylvania - the Company who had finished the massive 600 acre Locomotive in 1928 with a capacity for 3000 Locomotives a year it had never realised more than a 3rd of that capacity and so had quickly been able to retask many parts of the factory into tank production and had been building the M3 Lee before getting the M6 order so had gained significant experience.

By May 1943 the factory along with The Fisher Body Tank Arsenal in Grand Blanc, MI had reached their combined goal of 250 tanks a month and several revisions of the design had been undertaken by this time to both improve the design and streamline production.

Arriving in theatre too late to impact the North African Campaign the M6 does however see service with the British and Americans during Operation Husky - of significant note is the 36 M6 tanks of the experienced 601st Heavy Tank Battalion which meet and defeated Tiger tanks (as well as Italian Semovente L. 40 and German Pz4s) during the 2nd day of the Battle of Gela (and in doing so earned its 2nd of 3 Presidential citations awarded to this unit during the war)

Battle experience throughout the Sicily campaign and subsequent Italian battles - lead to further improvements - including revised crew layout and increased armour across the upper hull glacis and turret front and addressing some reliability issues.

Meanwhile with increased numbers of Tiger tanks reported and a new heavy tank called the Panther* having entered service and expected to be seen in some numbers in France - the US look to try and replace the M6 with the heavier M29 - a very heavily armoured vehicle with a long 90mm Anti tank gun - however despite their best efforts this tank is not ready in time for the Normandy campaign and the M6 continues to carry the burden - but by wars end half the ETO US Army Heavy Tank Battalions had received M29 Heavy tanks.

*The Wallies originally thought that the Panther was a Heavy tank like the Tiger not an improved medium

 

[MattII]

21st Panzer was the only one close on D-Day, and had lost many of it's tanks by June 8. The big problem was not gaining Caen on time, before the area was reenforced by Panzer Lehr and 12th SS, that had more of the Big Cats.

I will note however that none of the landings achieved their aims, so it wasn't a uniquely British fault.

 

[Riain]

Type Factory Dates Number Produced
M4 (Sherman I) M4 5 U.S. Factories Jul 1942 – Jan 1944 6748
M4(105): (Sherman Ib) M4(105) Chrysler Detroit Tank Arsenal Feb 1943 – Mar 1945 1641
M4A1: (Sherman II) M4A1 4 U.S. Factories Feb 1942 – Jan 1944 6821
M4A1(76): (Sherman II) M4A1(76) Pressed Steel Car Company Jan 1944 – Jun 1945 3426
M4A2: (Sherman III) M4A2 4 U.S. Factories Apr 1942 – Jun 1944 7513
M4A2(76)W: M4A2(76)W 2 U.S. Factories Jun 1944 – Jun 1945 2915
M4A3: Sherman IV M4A3 Ford Motor Company Jun 1943 – Sep 1944 1690
M4A3(75)W: M4A3(75)W Fisher, Grand Blanc Arsenal Feb 1944 – Mar 1945 3071
M4A3(76)W: M4A3(76)W 2 U.S. Factories Mar 1944 – Apr 1945 4542
M4A3(105): M4A3(105) Chrysler Detroit Tank Arsenal Jun 1944 – Jun 1945 3039
M4A3E2: M4A3E2 Fisher, Grand Blanc Arsenal May 1944 – Jul 1944 254
M4A4: (Sherman V) M4A4 Chrysler Detroit Tank Arsenal Jul 1942 – Sep 1943 7499
M4A6: M4A6 Chrysler Detroit Tank Arsenal Oct 1943 – Feb 1944 75
Grand Total: 49,234

Pick a factory.

The plan was to build M6 at Baldwin Locomotive and Fisher Body works, so there is no need to take Sherman capacity from any of their lines. Given they don't use common engines or in 1942-43 common guns they only thing making 5000 M6s will take from Sherman production would be the steel allocation.

10/M18/M3s would be a different story given the M6 used 76mm and 37mm guns in common with these types. However was High velocity gun production a bottleneck in 1943?

 

[hipper]

Also, for example, the M26 used 4x as much gas as the Sherman to cover the same distance. You will never have the same speed of advance, will never get the big breakthroughs, and will have to fight all the way across France, instead of racing across in weeks.

This is the sort of thing that sounds reasonable except that it's not actually true. The 4th Bn grenadeer guards were equipped with Churchills which managed a top speed of about 15 -

21st Panzer was the only one close on D-Day, and had lost many of it's tanks by June 8. The big problem was not gaining Caen on time, before the area was reenforced by Panzer Lehr and 12th SS, that had more of the Big Cats.

That did mask the problem that 7th Armoured Division underperformed in Normandy.

In wargaming terms, they had hit their preservation limit early on.

Why would getting to Caen stop the Germans reinforcing the Eastern side of the Beachhead with armour preferentially to the western side?
I'm also fascinated to know why what metric the 7 th armoured Division in Normandy.

 

[Cryhavoc101]

On the subject of 21st Panzer getting to the beaches on D-day etc and 'underperforming British troops' not capturing Caen here is a map showing advances etc by midnight

Note the several kilometer wide gap between Juno and Sword beach that elements of 21st Pz advanced down (road to Luc)

I don't think that a different tank would have made any difference on D-day as the main reason Caen was not captured on D-day was delays on the beach and a force that was too weak to capture the town in the face of the only German armoured unit in the area.

The most important thing for the allies was not to lose!

Edit : here is the map