"Extra turret plate?" Topic

Anybody know what the extra metal plate on the turret roof of this Panzer IV is? It looks pretty thin, so unlikely to add much protection to the turret roof and it is an unlikely place to be hit by Russian AT rifle rounds which is what the turret and hull skirts were for.
goo.gl/images/ZLNiGb

I would say it's anti-grenade protection. Some added spaced armour is better than none.

They were added to some German tanks as extra protection against strafing aircraft. You also see the same thing on Panthers, especially the more vulnerable engine deck…

Damon.

If you are talking about the skirts on IvH then the concept is to impede the effectiveness of a round. HE-P will explode early and cause less spalling. HE-AT will ignite the gas stream early and rarely penetrate the compartment. sABOT will be the least affected but could fail to penetrate due to a reduced velocity.

After posting I found that indeed some late models did have a plate added to the top. Learn something everyday!

Sand bags and track treaded were common ‘extra' armor for the USA. Even n Vietnam these two were used plus ammo cans filled with dirt.

Nope, roof armor. See this Panther:

Damon.

Could it be to keep snow from clogging the exhaust fan or interfering with the periscopes, etc.? It doesn't look thick enough to provide much protection.

Just guessing,
Mark

BTW the caption on the PzIV photo is a little suspect to me. It says it is from the Winter of '43, but I'm fairly sure the tank depicted in a PzIVJ with no zimmerit & either 3 or 4 return rollers (can't see exactly because of the picture cropping), so could only have come after Sept '44 when Zimmerit was discontinued. Could also be an early H retrofitted too, but I don't think it has the side visors for the fighting compartment, nor does it have the bolted on 30mm plates on the hull front early Hs without Zimmerit often had. So I think this is more like winter '44 or '45 IMHO…

Damon.

Interesting. Never seen this kind of armor on a Pz IV, or a Panther, before.

They were added to some German tanks as extra protection against strafing aircraft.

Seems plausible to me. The plates look similar to schurzen, which was 8mm mild steel plate.

If you look at the upper right corner of the plate on the Pz IV, you can get an impression of the plate's thickness. There is clearly some thickness present, but less than a finger width. So 8mm (about 1/3rd of an inch) looks about right to me. Also note how the plate bows downward a bit over the width of the turret. So probably not a very hard/stiff/brittle plate. All seems to fit.

If you are talking about the skirts on IvH then the concept is to impede the effectiveness of a round. HE-P will explode early and cause less spalling. HE-AT will ignite the gas stream early and rarely penetrate the compartment. sABOT will be the least affected but could fail to penetrate due to a reduced velocity.

Schurzen was developed and adopted to defend against HE rounds up to 76.2mm, and 14.5mm ATR rounds. HEAT and SABOT were not a threat on the battlefield when it was developed and adopted, and any impact it had on those rounds was a lucky side-effect rather than a reason for mounting it.

The effect on kinetic energy penetrators was not so much to slow the projectile, but rather to turn it. Kinetic energy penetrators tend to turn into the plate, and frequently pass through pointing a slightly different direction than their direction of travel. This is particularly true in cases of substantial over-penetration (ie: the projectile passes through the plate reasonably easily). German tests (and AARs after it was deployed) describe the slide-slap scars on the underlying armor plates that testified to the effectiveness of the schurzen in its intended role.

If I wanted to defend from .50cal, 20mm, or even 23mm rounds from strafing aircraft, I could see using the same techniques that protect me from 14.5mm ATRs.

However, I must wonder if it was effective in this role. First, it is only spaced a few inches off of the roof armor. I doubt that rounds passing through could be much off-axis before they struck the underlying armor. Second, the plates cover only portions of the upper surface. Fire from automatic weapons will find such gaps pretty regularly. If you are defending about automatic weapons, you tend to over-lap your plating, rather than leaving gaps between the plates.

All of this indicates to me that if this was indeed intended to defend against aircraft automatic weapons fire, it was probably a field expedient -- not terribly well thought out, and not successful enough to warrant being widely adopted. Which would explain why it was rare enough to be seen in only a few pics.

Just some ponderings…

-Mark
(aka: Mk 1)

Could it be protection against this: en.wikipedia.org/wiki/RPG-43

Separate double plates of armour are more effective than the same thickness of both together.
The jerries did a bunch of experiments before adopting the double thickness shields on atg.
There are several effects going on.
As I understand it anyhow.

It's also possible that the plates didn't offer quite the extra protection they hoped for.
I read of some experimentation with extras like sandbags on shermans. The conclusion was that their main benefit was to morale. There's very little done on that one though.

Could it be protection against this: link

Unlikely. It would be a spectacular throw to get it to land at the right angle on the top of the turret.
As I understand it spaced armour has 2 effects against KE rounds. It strips the penetrating cap off the round and it causes it to tumble. Both impare it's ability to penetrate the next layer of armour.

Amazing how few people seem to read the actual OT before spewing forth their … "knowledge" …

@War Drone

A common feature on TMP.

It would be unlikely to be hit by anti-tank rifle bullets unless it was a vulnerable target point. In which case it probably was and that is why it is there.

Separate double plates of armour are more effective than the same thickness of both together

Or not so much.

link

15+15 mm armour plates can be penetrated at up to 5 degrees from 50 meters, but solid 30 mm armour plates cannot be penetrated at that distance at all.

It was added to help protect against strafing aircraft. i generally have seen it on Panthers though and dont recall ever seeing it on panzerIVs. used to cover the engine deck as well.
link
link