Armor and Optics
The lower hull of the Sturmtiger was that of the Tiger I and remained unchanged. Nominally, the armor on the Tiger I consisted of a lower front hull plate 100 mm thick, a short glacis 60 mm thick and a reclined driver’s plate 100 mm thick. The sides were a uniform 80 mm thick and vertical on both lower and upper section, and 80 mm thick on the back. Due to manufacturing tolerance allowance of 0 to +5%, many of these plates ended up being recorded as slightly thicker i.e. 102 mm instead of 100 mm.
For the Sturmtiger, the turret was removed, as was the roof of the hull over the fighting compartment. Further, the driver’s plate was mostly gone, with the top half of it cut-off across the full width. Replacing all of this was a large flat-sided box containing all the crew and the main gun. The front of this box was made from a single slab of armor plate 150 mm thick angled back at 45 degrees which extended down to a point about halfway along the length of the glacis. It was held to the front of the hull by two substantial armor plates bolted over the joint. In the front of the plate was a large, armored ball-mount 69 mm thick for the 38 cm mortar and a small ball-mount for the forward-firing M.G.34 machine gun. The gun and mount were also protected by a 150 mm thick mantlet. On the left of the gun was a rectangular opening which took the aiming telescope and, below this, a pair of small visors under a small cowl were placed for the driver. The sides and rear were made from slabs of armor 80 mm thick but angled inwards towards the roof, which was 40 mm thick. On the prototype, an additional 50 mm thick slab of armor was bolted to the lower front hull of the Sturmtiger, but this feature was dropped from production vehicles, presumably to save weight.
Sources: 38 cm RW61 auf Sturmmörser Tiger ‘Sturmtiger’ - Tank Encyclopedia (tanks-encyclopedia.com)
