Panzer II w/ 37mm

[ArmchairSamurai]

Hello all.

I am not sure if this post really belongs here or not, but I just found the photo below and I find the theoretical implications fascinating. It sure looks like a Panzer II turret with a 37mm gun. Sure enough, it is. This turret was used on the Atlantik Wall as a static defensive position, and the configuration was never applied to the tank from which the turret is taken. I dug a little deeper and found this article: Panzer II Turret with 37mm found buried in Poland

What do you all think? Would be interesting to speculate Panzer IIs running around either with the 2 cm KwK 30 or the 3.7 cm KwK 36 the Panzer III had OTL in the early war, meanwhile, the Panzer III went with the 5 cm KwK 38 that was advocated for by some but ultimately passed over until later in the war. Interesting stuff.

 

[Cjc]

Well the stuart did fine enough I guess with its 37mm gun I don't see why the panzer 2 couldn't do the same.

 

[JWilly]

When considering re-arming an AFV, the first question always is: what's the tank's turret ring diameter, vs. the desired gun's (a) full recoil distance past the turret rotational axis as the gun would be mounted, and (b) longest ammo length in line with the breech with the breechblock open. Those two dimensions show whether the gun would be able to be fired at relatively long range, i.e. while elevated, and whether the gun would be loadable.

A second and more strategic question is, what is the AFV's strategic purpose, not in the past when it was designed and first fielded, but in the future?

This question arose multiple times in WWII for the Germans...for instance, in regard to the SdKfz 234/2 "Puma"...and also for the French, British and USA, mostly in regard to armored car armament.

The PzKpfW II originally was built as a light battle tank. It could fight relatively effectively against many of the opposing tanks of the late 30s.

But by 1940, its role was mostly reconnaissance and penetration screening. As such, it was doctrinally expected to advance to contact with the enemy, then retreat so as to be able to report back what it had observed. German reconnaissance specifically directed that forward reconnaissance elements were not to fight the enemy. But, for the Germans and all other armies, getting compliance with this doctrine was difficult. Recon personnel wanted to fight, and were eager in many cases to take more powerful equipment on "recon" missions so that they could engage the enemy forces they found.

Certainly that happened with Puma: certain panzer division recon commanders worked directly with Bussing, misleading the 234's manufacturer into thinking that there was high-command authorization for the upgunned "Puma" design. That lasted for less than a year, until it was sorted out that the seven divisions that had received Pumas were taking higher losses among their recon elements, because the recon personnel were encouraged by the heavier armament to fight instead of immediately withdrawing, Thereafter 234 production was switched to a more doctrinally consistent 2.0cm gun.

My guess is that it might have happened with PzKpfW II as well, if it had been upgunned to the 3.7cm L/45.

 

[Pioneer]

When considering re-arming an AFV, the first question always is: what's the tank's turret ring diameter, vs. the desired gun's (a) full recoil distance past the turret rotational axis as the gun would be mounted, and (b) longest ammo length in line with the breech with the breechblock open. Those two dimensions show whether the gun would be able to be fired at relatively long range, i.e. while elevated, and whether the gun would be loadable.

A second and more strategic question is, what is the AFV's strategic purpose, not in the past when it was designed and first fielded, but in the future?

I like your analogy JWilly

ArmchairSamurai, please don't take my following thought process as criticism or belittling - it's just my blunt non-filtered thought process under the effects of COVID mate.


I'm only speculating, but could it be that this 3.7cm armed turret was only feasible because it was mounted on such a bunker complex, which is immediately larger and more stable than the hull of the PzKpfw II?
If one looks at the turret arrangement of the PzKpfw II (see attachment), one will notice that by definition of its small turret size, that the 2cm KwK 30 cannon and the MG 34 are well spaced apart. This seperation of weapons arrangement I assume was because the commander seating arrangement and ability to operate within the turret and servicing the 2 cm cannon (see attached photo to appriciate how close the back of the turret the existing 2cm KwK 30 is).
One can only assume the 37mm gun would have to be fitted closer further to the centreline of the turret, because of its greater bulk and accessibility to serving it.
I can only assume the 3.7cm KwK 36 incorporated a recoiling system, which travelled the breech further into the turret on firing....Now I'm no buckethead, but I've had the privilege of being in the Leopard 1 and M1 when firing and whether its a 37mm, 105mm or 120mm, they're all gonna hurt you face in one form or another on firing if you are partially or fully behind that breech when it recoils.

Then I guess there's the issue of ammunition storage and handling within the confines of the small PzKpfw II turret and hull.
How many rounds of 3.7cm do you think you'd safely and ergonomically fit in the confines of a PzKpfw II? (Keeping in mind you have the loader/radio operator already sitting on the floor. (With the 3.7cm KwK 36 being larger, centred and recoiling, will the loader be able to function effectively as a loader?)

How much difference in additional weight will this make to the operation of the PzKpfw II?
How much effect will this the additional weight of the gun mantlet, the 3.7cm KwK 36 and the given 3.7cm ammunition effect the general overall performance of the PzKpfw II? (Ground pressure and PWR immediately comes to mind for me.). This might dictate wider tracks to offset the ground pressure, these tracks themself would add further weight.....

So, getting back to the modified bunker-mounted 3.7cm KwK 36/PzKpfw II turret arrangement, everything roomy under the turret ring might be why such a modification was workable (to a degree)

Regards
Pioneer

 

[poky]

Gun depression and elevation could also be part of. In a bunker with fixed lines of fire and low to the ground depression is less needed but in a mobile tank depression is very handy

 

[Cjc]

When considering re-arming an AFV, the first question always is: what's the tank's turret ring diameter, vs. the desired gun's (a) full recoil distance past the turret rotational axis as the gun would be mounted, and (b) longest ammo length in line with the breech with the breechblock open. Those two dimensions show whether the gun would be able to be fired at relatively long range, i.e. while elevated, and whether the gun would be loadable.

A second and more strategic question is, what is the AFV's strategic purpose, not in the past when it was designed and first fielded, but in the future?

This question arose multiple times in WWII for the Germans...for instance, in regard to the SdKfz 234/2 "Puma"...and also for the French, British and USA, mostly in regard to armored car armament.

The PzKpfW II originally was built as a light battle tank. It could fight relatively effectively against many of the opposing tanks of the late 30s.

But by 1940, its role was mostly reconnaissance and penetration screening. As such, it was doctrinally expected to advance to contact with the enemy, then retreat so as to be able to report back what it had observed. German reconnaissance specifically directed that forward reconnaissance elements were not to fight the enemy. But, for the Germans and all other armies, getting compliance with this doctrine was difficult. Recon personnel wanted to fight, and were eager in many cases to take more powerful equipment on "recon" missions so that they could engage the enemy forces they found.

Certainly that happened with Puma: certain panzer division recon commanders worked directly with Bussing, misleading the 234's manufacturer into thinking that there was high-command authorization for the upgunned "Puma" design. That lasted for less than a year, until it was sorted out that the seven divisions that had received Pumas were taking higher losses among their recon elements, because the recon personnel were encouraged by the heavier armament to fight instead of immediately withdrawing, Thereafter 234 production was switched to a more doctrinally consistent 2.0cm gun.

My guess is that it might have happened with PzKpfW II as well, if it had been upgunned to the 3.7cm L/42.

Consdering both us and ussr doctrine quickly moved to hole armored battalions acting as recon elements it seems to me those divisions had the right of it, lot eseyer to scout if you can push through the enemys screen.

 

[JWilly]

Consdering both us and ussr doctrine quickly moved to hole armored battalions acting as recon elements it seems to me those divisions had the right of it, lot eseyer to scout if you can push through the enemys screen.

A whole battalion cannot be on point, and first to see the enemy and estimate their numbers, armament and defensive preparedness. That has to be a particular vehicle.

And, German WWII panzer divisions already had "whole battalions" tasked with recon. But--recon, not fighting.

In 1944, German statistics showed that recon elements that were equipped and permitted to fight the enemy tended to not report as often, because they were dead. And, divisions that got early and complete recon reports were more effective than those that allowed their recon forces to try to fight. That's why the seemingly exciting Puma idea was quashed, and replaced with something much less exciting to those who are not objective-evidence-driven, but statistically more role-effective.

 

[Cjc]

Consdering both us and ussr doctrine quickly moved to hole armored battalions acting as recon elements it seems to me those divisions had the right of it, lot eseyer to scout if you can push through the enemys screen.

A whole battalion cannot be on point, and first to see the enemy and estimate their numbers, armament and defensive preparedness. That has to be a particular vehicle.

And, German WWII panzer divisions already had "whole battalions" tasked with recon. But--recon, not fighting.

In 1944, German statistics showed that recon elements that were equipped and permitted to fight the enemy tended to not report as often, because they were dead. And, divisions that got early and complete recon reports were more effective than those that allowed their recon forces to try to fight. That's why the seemingly exciting Puma idea was quashed, and replaced with something much less exciting to those who are not objective-evidence-driven, but statistically more role-effective.

I would recommend looking up ussr recon battalions, and us calvery regiments. Gust getting recon reports means nothing, gust because you got one dosnt mean its any good if all your recon saw was the enemys screen. That bit the Germans (and Americans as well) in the ass multiple times during the war, its why recon in force is the standard these days. Getting an enemy to engage your recon gives one a lot more information then what is generally considered recon.

 

[JWilly]

Getting an enemy to engage your recon gives one a lot more information then what is generally considered recon.

Then the argument is not for just an up-armed PzKpfW II, but an entirely different theory of how mechanized forces conduct recon, from the one that Germany used through most of WWII.

And whether recon-to-contact-then-retreat or recon-that-overpowers-screens is the doctrine, there is no effective recon taking place unless the recon elements survive long enough to report. So if they're to fight through screens, they must be equipped well enough to at least initially survive.

KwK 3.7cm guns wouldn't have been available to mount in PzKpfW IIs until they began to be removed from PzKpfW IIIs. By that time, PzKpfW II's frontal armor no longer was survivable in combat against even second tier AT guns...and it was known relatively early that the PzKpfW II suspension and powertrain could not handle the additional frontal armor to achieve that survivability.

It would have been common in recon-that-overpowers-screens for the defenders to be hidden well enough to get the first shot. Given those facts, if the German doctrine had been recon-that-overpowers-screens, then a mid-war PzKpfW II...no matter what gun it carried...would have had no efficient role in recon, because it would have been combat-ineffective against AT guns.

With such a recon doctrine, the efficient gun instead would have been one that could fire (1) effective single-round masking smoke to permit withdrawal, and (2) effective HE/fragmentation to counterattack AT guns. That would have been the 7.5cm L/24. But the smallest vehicle that could carry that gun and enough armor to have a chance of surviving first contact was the PzKpfW III chassis, with or without a turret.

 

[JWilly]

I may not have adequately responded to the full import of the OP's actual suggestion:

Would be interesting to speculate Panzer IIs running around either with the 2 cm KwK 30 or the 3.7 cm KwK 36 the Panzer III had OTL in the early war, meanwhile, the Panzer III went with the 5 cm KwK 38 that was advocated for by some but ultimately passed over until later in the war.

In 1939-40, Germany built 3.7cm guns as fast as they could. All of them were prioritized for either PzKpfW III tanks or PaK 36 towed guns.

Germany produced 5.0cm guns in the same production facilities that built 3.7cm guns. They could not keep building 3.7cm guns at the prior rate and build 5.0cm guns. The two gun calibers utilized all of the same factories and production halls, and most of the exact same machine tools. And, those production resources were working three shifts a day plus weekends.

Germany's armaments ministry did not switch to manufacture of the 5.0cm L/60 as soon as national leadership had originally directed because the L/60 barrel required new barrel rifling lathes, which were expensive and time consuming to build. Germany instead built a generation of 5.0cm L/42 guns specifically because that barrel length could be manufactured using the existing rifling lathes that previously had been used for 3.7cm L/45.

It must be recognized that a suggestion to install 3.7cm L/45 in new and existing PzKpfW II and simultaneously install 5.0cm L/60 (i.e. KwK 38), or even 5.0cm L/42, in new and existing PzKpfW III, could only have been accomplished once enough guns of the two calibers had been built and/or enough additional machine tools had been built to increase gun production capabilities...or else new-AFV production would have had to be cut to be consistent with the total 3.7cm-and-5.0cm gun production capacity, some of which now would be going toward PzKpfW II.

 

[Cjc]

Getting an enemy to engage your recon gives one a lot more information then what is generally considered recon.

Then the argument is not for just an up-armed PzKpfW II, but an entirely different theory of how mechanized forces conduct recon, from the one that Germany used through most of WWII.

And whether recon-to-contact-then-retreat or recon-that-overpowers-screens is the doctrine, there is no effective recon taking place unless the recon elements survive long enough to report. So if they're to fight through screens, they must be equipped well enough to at least initially survive.

KwK 3.7cm guns wouldn't have been available to mount in PzKpfW IIs until they began to be removed from PzKpfW IIIs. By that time, PzKpfW II's frontal armor no longer was survivable in combat against even second tier AT guns...and it was known relatively early that the PzKpfW II suspension and powertrain could not handle the additional frontal armor to achieve that survivability.

It would have been common in recon-that-overpowers-screens for the defenders to be hidden well enough to get the first shot. Given those facts, if the German doctrine had been recon-that-overpowers-screens, then a mid-war PzKpfW II...no matter what gun it carried...would have had no efficient role in recon, because it would have been combat-ineffective against AT guns.

With such a recon doctrine, the efficient gun instead would have been one that could fire (1) effective single-round masking smoke to permit withdrawal, and (2) effective HE/fragmentation to counterattack AT guns. That would have been the 7.5cm L/24. But the smallest vehicle that could carry that gun and enough armor to have a chance of surviving first contact was the PzKpfW III chassis, with or without a turret.

I mean I literally said Germany reconnaissance dacron was bad during ww2 and the Americans and ussr switched to reconnaissance in force during the war (Germany baken was really saved erly in the war by having air superiority during a time when most people were not very good at hiding things)

And yes the PzKpfW III would have been a better tank for this, thing is Germany really didn't have enough as is, so useing PzKpfW II with a up gun is really gust making the best of a bad situation.

These days recon (agenst a per power) is generally handled by MBT's with over strength IFV support.

 

[Foo Fighter]

As an ex gunner/loader I look at this from a slightly different angle. A cramped turret would reduce situational awareness via increased workload. The reduction in efficiency would make it a bit pointless, a fixed emplacement is not such a problem.