ARMOR ARRANGEMENT ON GERMAN TANKS
Tactical and Technical Trends, No. 29, July 15th 1943
The accompanying sketches show the armor arrangement on current models of the PzKw 2, 3, 4, and 6. These sketches are believed to be accurate and up-to-date. Armor thicknesses (circled figures) are given in millimeters; their equivalent in inches may be found in the article beginning on page 30. A question mark following some of these figures indicates that definite information is not available. Where two small figures appear in parentheses, it indicates that there are 2 plates at this point; in only 2 instances, namely on the PzKw 3, are the 2 plates separated to form so-called spaced armor.
The armament of these tanks is also shown.
Subsequently on January 5, 1943, Hitler decided to make all Panzer IV with 80 mm frontal armor. To simplify production, the vision ports on either side of the turret and on the right turret front were removed, while a rack for two spare road wheels was installed on the track guard on the left side of the hull. Complementing this, brackets for seven spare track links were added to the glacis plate. For operation in high temperatures, the engine's ventilation was improved by creating slits over the engine deck to the rear of the chassis, and cold weather performance was boosted by adding a device to heat the engine's coolant, as well as a starter fluid injector. A new light replaced the original headlight, and the signal port on the turret was removed. On March 19, 1943, the first Panzer IV with Schürzen skirts on its sides and turret was exhibited. The double hatch for the commander's cupola was replaced by a single round hatch from very late model Ausf. G. and the cupola was up-armored as well. In April 1943, the KwK 40 L/43 was replaced by the longer 75-millimetre (2.95 in) KwK 40 L/48 gun, with a redesigned multi-baffle muzzle brake with improved recoil efficiency.
A U.S. report on the German practice of mounting armor skirts (Schürzen) on panzers in WWII, from Tactical and Technical Trends, No. 40, December 16, 1943 is reprinted below: