ENEMY USE OF SKIRTING ON TANKS
Tactical and Technical Trends, No. 42, January 13th 1944
An examination of German Pz Kw 3 and 4 tanks in Sicily, and a number of SP guns has confirmed prior reports that the Germans are using skirting both around the turret and along the sides of the hull. A prior reference to enemy use of armor skirting on German tanks may be found in Tactical and Technical Trends No. 40, p. 11.
On one Pz Kw tank, 1/4-inch mild steel plates were placed around the sides and rear of the turret, and extended from the turret top to the bottom, almost flush with the top of the superstructure. The front edges on both sides had been turned in, so as to line up with the front of the turret, thus filling the space between the turret and the outer mild steel plate. Doors are provided in the outer plate immediately opposite the doors of the turret. The plate is bolted on to brackets by 3/8-inch bolts and studs. The plates stand out about 18 inches from the top and 12 inches from the bottom of the turret. The depth of the plate is approximately 20 inches.
The skirting of 3/16 inch mild steel plates is in sections of 3 feet 9 inches x 3 feet 3 inches. It extends from the top of the superstructure to about the tops of the bogies, and for the full length of the hull. The sections are held in place by slots in them which match the supporting clips on a 1/4-inch angle-iron rail, welded on to the top of the superstructure and extending the full length of the hull, and by 5 brackets bolted on to the track mudguards. The angle-iron is spaced about 15 inches outwards away from the hull, and the brackets about 8 inches away from the mudguards.
Three other Pz Kw 4 tanks, similarly equipped with skirting were also seen, and a Pz Kw 3 tank had both sides completely covered with sheets of 3/16 inch boiler plate extending the whole length of the tank, and reaching from turret-top level to the tops of the bogies.
The 7.5-cm Stu.K. 42 SP equipment on a Pz Kw 3 chassis has been seen with similar additional side plates. The plates, which extend vertically from the top of the equipment to the tops of the bogies, and laterally from the fifth bogie to the rear of the front-drive sprocket, are in three sections, the front section being cut to conform roughly with the shape of the equipment. A 15-cm s.F.H. 18 on Pz Kw 4 tank chassis is also reported to have been similarly equipped.
It would appear from available information that the use of spaced skirting on German armored vehicles and self-propelled guns is being adopted as standard practice. The fact that the side plates are in sections and held in place by clips suggests that they are detachable. This would, of course, be a great convenience in loading for transportation by rail.
It is believed that the skirting is designed to cause premature explosion of hollow charge, HE and AP HE shell, and thus minimize their effect. Although the plates have been described as mild steel, other sources have erroneously described them as armor.
Particular attention is drawn to the difficulty of recognition of tanks and SP equipments with this extensive skirting. Almost all of the features which are of primary importance in identification are obscured (see last sentence, Tactical and Technical Trends, No. 40, p. 11).
THE AusF. H
The next version, the Ausf. H, began production in April 1943 and received the designation Sd. Kfz. 161/2. This variant saw the integrity of the glacis armor improved by manufacturing it as a single 80-millimetre (3.15 in) plate. To prevent adhesion of magnetic anti-tank mines, which the Germans feared would be used in large numbers by the Allies, Zimmerit paste was added to all the vertical surfaces of the tank's armor.
The vehicle's side and turret were further protected by the addition of 5-millimetre (0.20 in) side-skirts and 8-millimetre (0.31 in) turret skirts. During the Ausf. H's production run its rubber-tired return rollers were replaced with cast steel; the hull was fitted with triangular supports for the easily-damaged side-skirts. A hole in the roof, designed for the Nahverteidigungswaffe, was plugged by a circular armored plate due to shortages of this weapon. These modifications meant that the tank's weight jumped to 25 tonnes (27.56 short tons), reducing its speed, a situation not improved by the decision to adopt the Panzer III's six-speed SSG 77 transmission, which was inferior to that of earlier-model Panzer IVs.
Panzer IV Auf.J with missing sideskirts Russia 1944.
The Ausf. J was the final production model, and was greatly simplified compared to earlier variants to speed construction. This shows an exported Finnish model.
Despite addressing the mobility problems introduced by the previous model, the final production version of the Panzer IV—the Ausf. J—was considered a retrograde from the Ausf. H. Born of German necessity to replace heavy losses, it was greatly simplified to speed production.
The electric generator that powered the tank's turret traverse was removed, so the turret had to be rotated manually. The space was later used for the installation of an auxiliary 200-litre (44 imp gal) fuel tank; road range was thereby increased to 320 kilometres (198.84 mi), The pistol and vision ports in the turret were removed, and the engine's radiator housing was simplified by changing the slanted sides to straight sides. In addition, the cylindrical muffler was replaced by two flame-suppressing mufflers. By late 1944, Zimmerit was no longer being applied to German armored vehicles, and the Panzer IV's side-skirts had been replaced by wire mesh, while to further speed production the number of return rollers was reduced from four to three.
In a bid to augment the Panzer IV's firepower, an attempt was made to mate a Panther turret—carrying the longer 75 mm (2.95 in) L/70 tank gun—to a Panzer IV hull. This was unsuccessful, and confirmed that the chassis had, by this time, reached the limits of its adaptability in both weight and available volume.