Side Armor on German Tanks.

[SilentOtto]

Has anyone come across any thing that discusses the effectiveness of
the additional armor that was added to later war German tanks?

I'm talking about the side protection that is most commonly seen on
later war MK IVs and Stugs.

What's the proper name for it?

Aside from the obvious answer of additional protection, was the
rational for such armor?

Was it to defeat shaped charges, add protection against weapons like
bazookas, cause HEAT rounds to pre-detonate, protect the drive wheels
or what?

I've always been curious about the details of such armor, and how much
additional protection it actually provided.

Thanks.

[Timo A. Nieminen]

Post by SilentOtto
Has anyone come across any thing that discusses the effectiveness of
the additional armor that was added to later war German tanks?
I'm talking about the side protection that is most commonly seen on
later war MK IVs and Stugs.
What's the proper name for it?

Chamberlain & Doyle, Encyclopedia of German tanks of World War
Two gives "Schuerzen" ("ue" = u with umlaut), translated as "armour
skirts", "skirt armour", or "armoured skirts". My dictionary gives "apron"
as a literal translation.

Post by SilentOtto
Aside from the obvious answer of additional protection, was the
rational for such armor?
Was it to defeat shaped charges, add protection against weapons like
bazookas, cause HEAT rounds to pre-detonate, protect the drive wheels
or what?

Yes, protection against shaped charge warheads. They're thin (5mm was
typical?), and mild steel. Pz IVJ used heavy wire mesh (as used on some
modern tanks).

Post by SilentOtto
I've always been curious about the details of such armor, and how much
additional protection it actually provided.

At the very least, it was believed to work well enough to be worth using.
That it is still used today to protect, e.g., turret sides on tanks,
infantry positions, etc., goes to show it works, at least somewhat.

[David H Thornley]

Post by SilentOtto
Was it to defeat shaped charges, add protection against weapons like
bazookas, cause HEAT rounds to pre-detonate, protect the drive wheels
or what?

Cause hollow-charge weapons to pre-detonate, in the hope that they'd
be less effective. Hollow-charge weapons would include bazooka
rounds and HEAT rounds.

I read some speculation a long time ago, and completely failed to
follow up, that this may not have been entirely a good idea. Hollow-
charge weapons function best with a certain standoff distance, which
was badly understood during WWII, and it's conceivable that some
of them might have worked better with a greater standoff
distance, provided by the standoff armor.

It was far too thin to provide any significant protection other
than to detonate hollow-charge rounds early.

[Michael Emrys]

It was far too thin to provide any significant protection other than to
detonate hollow-charge rounds early.

I have heard it bruited about that the original intent for Shuertzen
(the plate kind) was to provide added protection against anti-tank
rifles, which the Soviets fielded in great numbers throughout the war.
Later they, as well as the mesh variety (which were presumably much
cheaper to produce and repair/replace than even thin armor plate) would
also function against HC weaponry.

Michael

[Tero Mustalahti]

Post by Michael Emrys

It was far too thin to provide any significant protection other than
to detonate hollow-charge rounds early.

I have heard it bruited about that the original intent for Shuertzen
(the plate kind) was to provide added protection against anti-tank
rifles, which the Soviets fielded in great numbers throughout the war.

Yes. There is little actual written evidence to support the AT rifle
theory, but then again there is little evidence that would confirm the
hollow-charge theory either... Development and deployment dates of the
Schuerzen would seem to support the AT rifle theory. Their development
was started before the Germans captured Bazookas from US troops and also
before the first Soviet hollow charge AT weapons (the RPG-43 hand
grenade) were encountered, but the 14.5 mm AT rifles were common from
early 1942 on. Then again, the Germans also developed and deployed the
Zimmerit paste despite the fact that apart from captured German stocks
the Soviets did not manufacture or use magnetic mines at all...

What we DO know is that the Schuerzen did work quite well against the
Soviet 14.5 mm AT rifle rounds. The thin armor plate was enough to make
the bullet yaw, after which it no longer had any chances of penetrating
the actual side armor even at close ranges. Their performance against
HEAT rounds is more controversial, as has been already pointed out.


Tero P. Mustalahti

[JJR]

Post by Tero Mustalahti
Yes. There is little actual written evidence to support the AT rifle

theory

Still there is quite a lot in the net, including original WWII papers on
lonesentry.com, so this theory made its way into wiki description of Soviet
standard PTRD ATR rifle. For another hint here is a pic from wartime Russian
ATR manual http://tnij.org/clzh .

Post by Tero Mustalahti
What we DO know is that the Schuerzen did work quite well against the
Soviet 14.5 mm AT rifle rounds. The thin armor plate was enough to make
the bullet yaw, after which it no longer had any chances of penetrating
the actual side armor even at close ranges.

In fact you would have to sneak really close to get through side armor, not
necessarily an easy thing to do with this cumbersome rifle. So it was rather
used as a sniping weapon, with soldiers specifically encouraged to try for
weak spots like periscopes and hatches, or to stop the tank by damaging
bogie wheels/track suspension.

Post by Tero Mustalahti
Their performance against
HEAT rounds is more controversial, as has been already pointed out.

Looks like actual WWII soldiers had different idea - there is plenty of
pictures (even under link given above) showing Russian tanks in Berlin with
hastily mounted side protection against Panzerfaust and -schreck,
improvised of confiscated German wire beds. What's even more convincing,
contemporary Strykers in Iraq also feature similar arrangements - this
wouldn't be done if their performance were controversial.

--
pzdr,
Jedrzej

"How horrible, fantastic it is that we should be digging trenches and trying
on gas-masks here because of a quarrel in a far away country between people
of whom we know nothing."
Neville Chamberlain -- 27 September 1938

[David H Thornley]

Post by JJR

Post by Tero Mustalahti
Their performance against
HEAT rounds is more controversial, as has been already pointed out.

Looks like actual WWII soldiers had different idea - there is plenty of
pictures (even under link given above) showing Russian tanks in Berlin with
hastily mounted side protection against Panzerfaust and -schreck,

Well, they made them, but that doesn't make it a good idea. Plenty of
US tanks carried piles of sandbags, for example, which cut performance
and were ineffectual against the AT weapons the crews were worried
about. Some Bomber Command bombers kept IFF on where it could only hurt
them, in the vain hope that it might interfere somehow with German radar.

Given a choice to do something that might help crew safety a little
bit, crews will often do it. People are not always rational and
calculating when being shot at.

Post by JJR
improvised of confiscated German wire beds. What's even more convincing,
contemporary Strykers in Iraq also feature similar arrangements - this
wouldn't be done if their performance were controversial.

There's a difference.

Hollow-charge weapons do best at a certain standoff distance, governed
by the physics involved (which I do not understand well). They were
not well understood during WWII, and therefore the distance from the
armor that a hollow-charge weapon was detonated had little to do with
the ideal distance. Postwar, there was a good deal of research on these
things.

Therefore, modern hollow-charge rounds detonate at the right distance
from the armor for maximum penetration, and anything that will increase
that distance will hurt penetration. WWII hollow-charge rounds did not
in general detonate at the right distance, and probably a lot of them
detonated too close. It's entirely possible that spaced armor pushed
at least some detonations back to where they were more effective.

Again, I don't understand the details, I don't know how to calculate
the best standoff distance, and I don't really know what the detonation
distances were for WWII weapons, so this is speculation.

[Walt]

If someone mentioned the Monroe Effect, I missed it:

Monroe effect

The Monroe effect refers to the characteristics of the detonation of a
volume of explosive around a hollow or void, a shaped charge.
Explosive energy is released directly away from (normal to) the
surface of an explosive, so shaping the explosive will concentrate the
explosive energy in the void. If the void is properly shaped (usually
conically), a high-velocity jet of plasma will form.

In military applications, a Monroe-effect shaped-charge warhead can be
expected to penetrate solid steel armor equal to 150-250% of the
warhead diameter.

http://www.knowledgerush.com/kr/encyclopedia/Monroe_effect/

The plasma jet is what pentrates the armor of course. That is why the
velocity of the warhead is immaterial. Get that jet going and you are
through the armor.



Walt

[Tero Mustalahti]

Post by Walt
In military applications, a Monroe-effect shaped-charge warhead can be
expected to penetrate solid steel armor equal to 150-250% of the
warhead diameter.

150% was typical for WW2 HC weapons and 250% for (early) 1950s HC
weapons -- at that time already called "HEAT" for "High Explosive,
Anti-Tank" in US milspeak, I believe. Modern penetration optimized
hollow charge weapons can reach up to ten times (1000%) the warhead
diameter, although 7-8 times is a more common figure for weapons in
actual service. Of course modern heavy armored vehicles tend to have
something else than just steel at least in the frontal armor and
increasingly in the sides as well.

Post by Walt
The plasma jet is what pentrates the armor of course. That is why the
velocity of the warhead is immaterial. Get that jet going and you are
through the armor.

Yes. It is notable, however, that it is not the temperature of the jet
that does the penetrating. It does not "burn through" or melt the armor.
The essential thing is the very high velocity of the jet and the
enormous pressure that it puts on the armor. The actual process is for a
major part hydrodynamic (in those pressures solid matter behaves almost
like a liquid), so you could say that the jet "flows through" the armor.


Tero P. Mustalahti

[Walt]

Post by Tero Mustalahti
Yes. It is notable, however, that it is not the temperature of the jet
that does the penetrating. It does not "burn through" or melt the armor.
The essential thing is the very high velocity of the jet and the
enormous pressure that it puts on the armor. The actual process is for a
major part hydrodynamic (in those pressures solid matter behaves almost
like a liquid), so you could say that the jet "flows through" the armor.
Tero P. Mustalahti

I didn't know that about the method of penetration. Thanks.

The US developed in WWII HEAT rounds for both the 75mm gun and the
105mm gun used by the M-8 SPG and ther M-7 SPG respectively.

So even a lowly M-7 could in theory kill a Panther or Tiger. I never
managed the trick playing Advanced Squad Leader though.



Walt

[Michael Emrys]

Post by Walt
So even a lowly M-7 could in theory kill a Panther or Tiger.

A direct hit even by ordinary 105mm HE, although it probably would not
achieve an armor penetration, would still likely achieve a mission
kill. Disabling running gear, shattering optics, possibly knocking the
turret off its races, or simply discouraging the crew by shaking them
up severely would do the job. The preferred method of attacking armor
with M7s still remains using indirect fire though.

Michael

[Tero Mustalahti]

Post by Michael Emrys

Post by Walt
So even a lowly M-7 could in theory kill a Panther or Tiger.

A direct hit even by ordinary 105mm HE, although it probably would not
achieve an armor penetration, would still likely achieve a mission kill.

Possibly, but it would likely require several hits. In fact getting a
single hit mission kill against a heavily armored tank like a Panther or
Tiger with 105 mm HE would almost certainly require either a side hull
or rear hit or a lot of luck. Disabling the running gear might not save
the day either, since the tank can still shoot back even if it can't move.

Post by Michael Emrys
Disabling running gear, shattering optics, possibly knocking the turret
off its races, or simply discouraging the crew by shaking them up
severely would do the job.

Yes, but none of those are automatic or even very likely on a single
shot basis in a frontal encounter. With a larger HE shell the picture
changes significantly, but 105 mm simply does not pack that much punch.


Tero P. Mustalahti

[Michael Emrys]

...none of those are automatic or even very likely on a single shot
basis in a frontal encounter.

True, but to put the matter in perspective, getting a single shot kill
in a frontal encounter against a Panther or a Tiger even with 76mm HVAP
or 17pdr APDS wasn't guaranteed either.

In the part of my post you chose not to quote, I made it clear that
dueling with German armor using M7s was not a good way to reach
retirement age.

Michael

[Tero Mustalahti]

Post by Michael Emrys

...none of those are automatic or even very likely on a single shot
basis in a frontal encounter.

True, but to put the matter in perspective, getting a single shot kill
in a frontal encounter against a Panther or a Tiger even with 76mm HVAP
or 17pdr APDS wasn't guaranteed either.

It wasn't guaranteed with any WW2 direct fire weapon at least in the
cases of Panther and Tiger II. But if I had to shoot one with a 105 mm
howitzer, I would rather use HEAT than HE.


Tero P. Mustalahti

[Walt]

Post by Tero Mustalahti
It wasn't guaranteed with any WW2 direct fire weapon at least in the
cases of Panther and Tiger II. But if I had to shoot one with a 105 mm
howitzer, I would rather use HEAT than HE.
Tero P. Mustalahti

Plus an M-7 crew wasnot likely to be very well trained on direct fire
with HEAT. I hope it didn't come up very often.



Walt

[David H Thornley]

Post by Walt
Plus an M-7 crew wasnot likely to be very well trained on direct fire
with HEAT. I hope it didn't come up very often.

I've read that gunners who actually saw the enemy thought things must
be going very, very wrong. I don't know if they got any training
in direct fire, but they certainly didn't get much experience.

[Walt]

Seems like when the fuse hits the armor (or the schurzen or whatever)
the electrical flow created by the fuse goes to the rear of the
warhead and the explosion is propagated back to front. The (usual)
conical nature of the shape charge then propagates the molton jet into
the target. That is the Monroe Effect.

Seems like we learned a way to make field expedient shape charges with
coke bottles (this was back in the 70's so I could be
misremembering). The Master Chief who taught that course could do
anything with explosives though.

To get in some WWII content, there was a PFC Towle who got the Medal
olf Honor engaging Tigers with the really inadequate 66mm rocket
launcher. Wikipedia:

Towle joined the Army from his birth city of Cleveland, Ohio, and by
September 21, 1944 was serving as a private in Company C, 504th
Parachute Infantry Regiment, 82nd Airborne Division. On that day, near
Oosterhout in the Netherlands during Operation Market Garden, Towle
engaged a German force with his rocket launcher in an attempt to
disable two enemy tanks and a half track. He was killed during the
battle and posthumously awarded the Medal of Honor six months later,
on March 15, 1945.

Towle, aged 19 at his death, was buried at Calvary Cemetery in his
hometown of Cleveland.


-------------------------

Walt