Fwd: Re: [MV] Extra Armour On WW2 Shermans

From: islander (islander@midmaine.com)
Date: Thu Sep 07 2000 - 23:57:09 PDT


****sorry if this is a dupe, but looks like it never made it through the
list server so far as I can tell****

Hello Brandon and Geoff,

>I can't speak to the effectiveness of the added track on the sides of the
>tank, but from a metallurgical standpoint it shouldn't have too much of an
>effect.

Indeed, they did not except for something like AT Rifle rounds (this was
not an issue for Shermans but was for German AFVs in the East). It would
appear that these field modifications were done more for morale reasons
since they lacked any real benefit against any type of AT round used by
the Germans.

Truth is that the Panzerfaust (30, 60, 100) had PLENTY of extra punch
when matched against every single Allied tank. The 60 and 100 could
penetrate 200mm of armor at 30deg angle. This is about 3-6 times the
thickness of most Allied tanks' frontal and side armor. So adding a
couple of mm of metal on the outside did absolutely nothing to help.
Same for the Panzerschreck, but it had less penetrating power (though
still plenty vs. an Allied tank)

The Germans used "skirt" armor to combat Soviet AT Rifles, but then found
to be quite effective against rocket propelled charged round (bazooka,
PIAT) impacts. The skirts could not ensure the vehicle would remain
operational after a hit, but it did give the crew a very good chance of
escaping direct harm. Downside (and there is ALWAYS a downside <g>) was
that they could become hung up on objects while moving and reduced
visibility in some cases.

Sandbags were used by Allied tankers in the hopes of offering better
protection as well. However, they were actually something that HELPED
the Panzerfaust get in a good kill hit. The sand basically helped the
shaped charge maintain its focus better and also aided in creating a more
optimal standoff point of contact. So it might have looked cool, but in
practice it was not such a good idea against either PF/PS or solid shot
rounds.

>I've heard that the extra weight would put severe strain on on the tank's
>drivetrain. How negative?

Extra plates of armor only effectively added about 50% of their thickness
to the equation. For example, if you have a 40mm armor plate with a 20mm
plate welded on top the resulting effective protection was equal to
roughly 50mm and not 60mm. So the extra weight caused mobility and
mechanical problems while only adding half the benefit of its thickness.

Remember that tanks, even when kitted out of the factory, were often
already straining their parts and optimal ground pressure. After crews
got done attaching everything but the kitchen sink this was made far
worse. This was especially true for earlier Shermans since they had
pretty bad ground pressure ratings from the get go. The latter HVSS
suspension system helped out a LOT in this regard (reduction from about
14psi to 10psi).

Also the welded-on armor was not necessarily face hardened, and therefore
was not as effective as the armor underneath it. Some Shermans were
reinforced with armored plates taken off of other Shermans (beyond
repair) so they were a bit better off since those plates were face
hardened.

Sources? Uhm... my partner has all of this stuff and he is a tad busy at
the moment. The above comes out of about 3 years worth of detailed
ballistics and physics research for a WWII simulation, comprising various
reports as well as commentary from contemporary physicists. There is a
good book out called "Death Traps", but I forget the author (who was
responsible for repairing/recovering AFVs in the ETO).

Hope this helps!

Steve



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