Need Sherman v Mark IV source material, pls...

[JonS]

many people think because it's a German tank it's superior.

Of course they do. Aliens don't hang Panther turrets off the bottom of their UFOs just it looks kewl, you know. And the Martians didn't ship a PzI back to Mars because they thought it worse than a Sherman.

[Lt Belenko]

Well, the PZIV LOOKS a lot meaner and tougher than the Sherman, that's for sure.

That's how I make force selection in QBs - pick the meanest toughest LOOKing unit.

[JasonC]

Which Sherman against which Mark IV?

If you cherry pick both, you can find narrow circumstances in which the IV is marginally better, but very briefly. Over most of the time and models available, the Sherman is better - by a wide margin both early and late, more nearly equal in the middle time frame (of the period they opposed each other, I mean).

When the Sherman first appeared, most IVs were still sporting short 75L24 guns and were hopelessly outclassed by the Sherman, and most of the German tank fleet it initially faced were IIIs with 50mm guns, not IVs. The Germans were in the process of upgunning their IV fleet to longer 75mm guns, initially 75L43 and not much later, 75L48s. But the older models were still in existence in 1942 with the longs scarce and mostly sent to Russia. 1943 is the transition year for the Germans when the majority of the fleet becomes upgunned - but still a third of the German tank fleet had older and weaker weapons in mid 1943. It takes time for older models built under previous conditions and assumptions to be lost in combat or (more rarely) modified.

In North Africa, the Shermans they faced were the early models without uparmoring. They were still much better protected than the IV, and that remained true throughout their fighting against each other. The front hull armor of the Sherman is as effective as that of the Tiger I, with slope effects included. The turret is softer but still much more effective than even the strongest front hull plate of the IV, while the IVs turret is quite weak - not quite like the side armors of either, but still penetrable to all likely combat ranges, even to the relatively weak gun on the short 75 Shermans.

The Sherman has a weaker gun until it is upgunned, which happened in the second half of 1944 basically. All the 1944 production after about February was upgunned types. But there was still a large park of the older types in the field, and US armor losses were so low they didn't go anywhere. The 76s came in mostly as upgraded to the fleet, in the later arriving armor divisions and as leavening replacements to the older formations. (The Brits already had a quarter Fireflies by summer and are another matter).

The short 75 Shermans are not all created equal, either. The later wet stowage models had significantly better armor protection and survivability. The German 75L48 could penetrate them at short range, but at medium range - 800 to 900 yards - were already having trouble penetrating their hull front. The Sherman is still penetrating every plate of the IV at those ranges. At 1200-1300 yards, it starts bouncing from the IVs hull front, and either side needs a turret hit to go in (from the front, mind - all penetrate in side aspect throughout). Open the range further again, and now the IV has trouble even against the Sherman turret front, while the Sherman can still kill through the IVs turret front most of the time.

Understand, the penetration of the Sherman's short 75 isn't static either. It improves when the US gets APCBC ammunition, which they had in 1944 and especially by summer.

Partly balancing those penetration issues, the 75L48 is a higher velocity gun and the IV has better optics, making it more likely to hit at longer range. It also has a somewhat lower profile. But in most cases, if the engagement starts in the range windows where either can penetrate the other, the first shooter is likely to be the first hitter and the first hitter is likely to win. That is the consistent report of the men in the field - the tank specs matter less than other tactical factors, above all who got the drop on the opponent.

Later, the Shermans get 76mm guns to go with their improved armor and it is no contest, the Shermans are better in every important respect. At that point it is a mid 1944 tank vs a mid 1943 tank, and the Sherman kills any range and aspect with any hit, using a gun of equal velocity, while the IV has serious issues with the Sherman hull front beyond close range. This is about as good a match up as the Panzer IV itself enjoyed over the T-34/76 in 1943, in favor of the Sherman 76.

As for their operational records, there is no question the Germans did quite poorly with their armor in the west, and the lesser vehicles - which the IV counts as in this period - cannot have done well against Shermans in relative terms. The US loses remarkably few mediums in the whole campaign, Shermans and TDs combined. A tiny portion of the number built, for example. The Germans did enjoy a lopsided kill ratio in the east against the Russians, but not so in the west.

The highest you can stretch the relative losses inflicted in the German's favor in the west as a whole would put it at 3:2, and 1:1 is closer to reality. And that outperformance is pretty much all slurped up by the superior portion of the German fleet mix, the Panthers, Tigers, and uparmored tank destroyers. The vanilla IVs and StuGs certainly did not break unity in their loss rates vs. Shermans. They faced bad operational odds and situations of course, but they were also used rather recklessly, and their field performance was pretty bad.

The only occasions you can find where German armor met US in the war and bested it are the first period in Tunisia where the Americans are extremely green, and the first week or so of the bulge fighting where the Germans have high local odds, including odds in the non armor supporting arms (infantry and artillery etc). Even those two occasions reverse in less than a month with losses to the German armor involved reaching 50%. They did better against the Brits in Normandy, and you can find a few cases of defensive use with more or less equal trading (e.g. Anzio). Every other large scale use of German armor aggressively in the west is a disaster - Gela, Salerno, Lehr in Normandy, Mortain, the Panzer brigades at the westwall, Lorraine in September, etc.

The notion that the German armor was superior in field performance and inflicted lopsided losses on its opponents is a myth in the west. It is true with the Russians and to a lesser extent supported by a few cases vs the Brits (Villars, Goodwood), but it simply didn't happen vs. the Americans. They came, they saw, they got their heads handed to them and ran off again. Not all to Shermans, to be sure, but all the same.

[Killkess]

And I maintain that the Sherman was slightly superior even to that. It wasn't until the Pz. IV received the L/48 gun that I think it deserves to be considered superior.

Michael

IIRC the difference in performance between L43 and L48 was marginal. The difference in muzzle velocity was only about 1% between the guns. The L43 uses ammonition with much higher chamber pressures compared to the L48. The design of the chamber, breech and so on was quit cumbersome for the L43 to deal with the high pressures. The L48 was much better suited for a tank turret.

[John Kettler]

WriterJWA,

I made a bad mistake in describing the Sherman gyrostabilizer. It stabilizes in elevation, NOT azimuth. Somehow, I got the two reversed. This rather heavy handed on the religious angle account by a PTO USMC Sherman crewman clearly indicates both what the device did and generally, how it worked. From the way he writes, he has direct experience with it. Also of interest is the equipment destruction priority--gyrostabilizer first.

http://www.grunt.com/corps/scuttlebutt/marine-corps-stories/the-gyrostabilizer/

Regards,

John Kettler

[dieseltaylor]

Humph! A bigger load of tosh is hard to imagine! I know speakers who like analogies ....

One of the keys to the effectiveness of both the Army and Marine Corps Sherman tanks was a little 6 x 8 inch black box called the Gyrostabilizer that was mounted alongside the .75 mm. Cannon and coaxial .30 caliber machine gun in the 15-ton Turret. The Gyrostabilizer was one of WWII's best-kept secrets. Our five-man crew had clear, urgent instructions that if we ever had to abandon tank, the Gyrostabilizer was the first and most important item to be destroyed. Also, the firing pin in the .75 mm cannon was to be removed and the back plates on all the machine guns were to be dismantled. There was a vital purpose to that little black box. As the tank was underway, often-times over extremely steep and rough terrain, the gyroscope inside the box, spinning in a vertical plane, kept the turret guns steady and level. No matter how much the tank bounced around, up and down, the gunner could stay on his target and fire on the move. The Gyrostabilizer gave us an unprecedented advantage in moving combat. Before its marvelous inception, tanks usually had to fully stop in order for the gunner to come on target. This made the tank a target itself. In my own life I need a Gyrostabilizer for the ups and downs of daily living. It seems there is much rough terrain, both small rocky bumps and great gullies. Right in my own home and family or with close loved ones and friends, I need steadiness.

Or in the course of my work there are plenty of rough spots and unexpected challenges. The loss of position, an incompatible boss or coworker puts my attitude to the test. The loss of my job. Or how about sickness, a serious illness or loss of a loved one? All of the above can be very rough terrain. What, or better yet, who gives you and me true stability? Jesus Christ is God's amazing Gyrostabilizer. He can and will keep us level and stable when we trust Him and cast upon Him all of our cares, anxieties and needs daily, for it deeply matters to Him about you and about me.

Apparently a .75mm gun !

[PzKpfw 1]

One thing to add the gyro stabalizer was only installed in 75mm Shermans. It was not installed on the 76mm models. Also as noted before 75mm M62 APCBC was more then capable of dealing with the PzKpfw IV H etc. Infact M62 was the round most fired in the ETO, the US converted thousands of M72 rounds to M62 after the Insigny live fire tests. Although its interesting the Soviets had no problems with the M72 rounds vs German armor.

Regards, John Waters

[Vanir Ausf B]

Also as noted before 75mm M62 APCBC was more then capable of dealing with the PzKpfw IV H etc. Infact M62 was the round most fired in the ETO, the US converted thousands of M72 rounds to M62 after the Insigny live fire tests. Although its interesting the Soviets had no problems with the M72 rounds vs German armor.

Hey John, we are having a little discussion about this over at the CMFI forum. The question of when M62 became available has come up since it represents a very significant performance increase over M61 against the Pz IV. Armor penetration tests and tables from 1943 and 1944 (at least through the Isginy tests in July '44) do not list M62. In fact, I'm not sure what the exact difference is between M62 and M61.

[John Kettler]

Pzkpfw1,

If you see a Grant or a Lee sporting something akin to a muzzle brake on the 75mm, it, too, is fitted with the gyrostabilizer. Here's a September 1944 POPULAR SCIENCE article on this somewhat revolutionary weapon. Starts page 82. Most information I've ever seen on the mysterious box.

http://books.google.com/books?id=AiEDAAAAMBAJ&printsec=frontcover&lr=&rview=1#v=onepage&q&f=false

The perception the article may've created is thoroughly dispelled in the same thread from whence came the link. Some of the sources cited in opposition include former WW II tankers from the 4th AD and official documents from the Armor School at Ft. Knox.

http://www.ww2f.com/armor-armored-fighting-vehicles/42966-main-gun-stabilizer-revealed.html

Westinghouse ad featuring the gyrostabilizer. Inset has an AP article regarding the Sherman in which Radio Berlin characterized the gyrostabilizer as a "special innovation" which "considerably interested" German experts.

http://books.google.com/books?id=YFAEAAAAMBAJ&pg=PA3&lpg=PA3&dq=Sherman+tank+gun+stabilizer&source=bl&ots=t5gf59Xfed&sig=wmDAVGxClS2148V4BiWWaNp6rzA&hl=en&ei=JADYTsy5OeOuiQLN7an-CQ&sa=X&oi=book_result&ct=result&resnum=6&ved=0CFIQ6AEwBQ#v=onepage&q=Sherman%20tank%20gun%20stabilizer&f=false

This is another short, but good, thread on the gyrostabilizer, including excerpts from several War Office tests.

http://theminiaturespage.com/boards/msg.mv?id=250226

dieseltaylor,

I thought the material on the box itself and the associated security was worthwhile, but could well have foregone the second paragraph. I did notice the subcaliber main armament, but did you notice the gyrostabilizer itself was 6x8 inches, making for a very space saving installation?!

Regards,

John Kettler

[akd]

Some people set up test ranges

Post reported. p.s. don't follow his link. looks like it earns him cash.

[PzKpfw 1]

Hey John, we are having a little discussion about this over at the CMFI forum. The question of when M62 became available has come up since it represents a very significant performance increase over M61 against the Pz IV. Armor penetration tests and tables from 1943 and 1944 (at least through the Isginy tests in July '44) do not list M62. In fact, I'm not sure what the exact difference is between M62 and M61.

Vanir, sorry about the late reply, my post should have said M61 APCBC, NOT M62. M61 performed better vs face hardened armor & sloped armor then M72 AP. The M72 conversion was to M61 APCBC.

Regards, John Waters